Abul Kalam, M & Hj Hassan, M 2011, 'Design, Modification and Testing of a Catalytic Converter for Natural Gas Fueled Engines', Arabian Journal for Science and Engineering, vol. 36, no. 5, pp. 677-688.
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Ahmad, RT, Nguyen, TV, Vigneswaran, S & Ho, DP 2011, 'Removal of effluent organic matter by purolite fluidised bed and submerged membrane hybrid system', Desalination and Water Treatment, vol. 32, no. 1-3, pp. 194-200.
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In this study, Purolite® A500PS was used to remove effluent organic matter in a fluidised bed and submerged membrane hybrid system (SMHS). It was found that the fluidised bed purolite column can effectively remove 73% of dissolved organic compound (DOC) from synthetic biologically treated sewage effluent (BTSE). DOC removal can be reduced further, by up to 95% when the fluidised bed purolite column was combined with a treatment by granular activated carbon column. Purolite® was also used as an adsorbent in the SMHS. The results showed that critical flux of the SMHS depend on the purolite size. Critical fluxes of SMHS were 30 and 35 L/m2.h where 0.1 g/L of purolite of sizes below 150 μm and 150-300 μm were used respectively. The removal efficiency of natural organic matter from synthetic BTSE by SMHS was a function of purolite dose. The removal efficiency increased from less than 60% to more than 70% when the purolite dose increased from 0.05g/L to 0.1g/L. © 2011 Desalination Publications. All rights reserved.
Aldridge, LP, Vessalas, K, Fernando, K, Costa, MD, Thomas, P & Ray, AS 2011, 'Comparison of durability measures of concrete as a function of cure times', Concrete in Australia, vol. 36, no. 4, pp. 42-47.
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This work forms part of a project for evaluating techniques of estimating concrete durability to improve service life. Here compressive strength, chloride diffusivity, void volume, and sorptivity from water cured concretes were measured at seven, 28 and 56 days to evaluate the concrete durability as a function of curing. It was concluded that while void volume and sorptivity were useful as quality control measures they did not reflect the increase in durability found when concrete was cured. This was in contrast to the chloride diffusivity and compressive strength results which showed marked differences during the curing of the concrete. For this study four concrete mixes were prepared using identical compositions of water, sand, and aggregates and having the same amount of cementitious materials with four different compositions: (1) Ordinary Portland Cement (OPC) (2) OPC with 20% replacement of a commercial fly ash (3) OPC with 40% replacement of the same fly ash, and (4) OPC with 20% replacement by pitchstone fines. Pitchstone fines are a waste product made during the production of expandable perlite aggregate which previous work has shown to act as a supplementary cementitious material.
Al-Harthy, AS, Stewart, MG & Mullard, J 2011, 'Concrete cover cracking caused by steel reinforcement corrosion', Magazine of Concrete Research, vol. 63, no. 9, pp. 655-667.
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The paper reviews previously reported predictive models on corrosion-induced crack initiation and propagation and presents new additional results of ongoing accelerated corrosion tests conducted at The University of Newcastle. In addition to eight concrete specimens previously tested, six new specimens were tested to study the effect of reinforcement confinement, concrete strength (24 and 8 MPa), cover (10 and 20 mm) and reinforcing bar diameter (16 and 27 mm) on corrosion-induced cracking. Time-dependent crack widths were measured for different reinforced concrete slabs for corrosion rates up to 169 μA/cm2. It was found that predictions of time to crack initiation are highly scattered and can differ by as much as two orders of magnitude. It was also found that crack initiation and propagation times increase with increasing cover and decrease with increasing reinforcing bar diameter and compressive strength. In addition, the rate of crack propagation is 10–50% higher for reduced reinforcement confinement such as at the edge of a slab or corner of a column. The experimental results are compared with existing crack initiation and propagation predictive models allowing for the accuracy of existing models to be assessed and showing potential areas for further research.
Al-Mahmoud, F, Castel, A, François, R & Tourneur, C 2011, 'Anchorage and tension-stiffening effect between near-surface-mounted CFRP rods and concrete', Cement and Concrete Composites, vol. 33, no. 2, pp. 346-352.
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Al-Rifai, JH, Khabbaz, H & Schaefer, AI 2011, 'Removal of pharmaceuticals and endocrine disrupting compounds in a water recycling process using reverse osmosis systems', SEPARATION AND PURIFICATION TECHNOLOGY, vol. 77, no. 1, pp. 60-67.
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A detailed investigation was carried out to evaluate the occurrence, persistence and fate of a range of micropollutants at different processing points at a full-scale water recycling plant (WRP) in Queensland, Australia. The WRP, which combines an advanced water treatment plant (AWTP) with a wastewater treatment plant (WWTP), produces high quality recycled water for industrial users. The concentrations of 11 pharmaceuticals from various therapeutic categories and two endocrine disrupting chemicals were examined in full-scale microfiltration and reverse osmosis membrane facilities. Salicylic acid was the most abundant analyte in the WWTP influent, with a concentration range of 11-38 μg/L, followed by bisphenol A with concentrations ranging from 6 to 23 μg/L. The concentration of all analytes decreased on average by one order of magnitude following primary and secondary treatment. Gemfibrozil, primidone and carbamazepine were found to have lower removal efficiencies (74-78%) than other compounds during these stages, which could indicate lower biodegradability. The microfiltration and reverse osmosis systems were found to further lower the pollutant concentrations by an order of magnitude. The overall removal efficiencies in the final recycled water were above 97%, resulting in product water concentrations of lower than 0.1 μg/L for most compounds. An exception to this finding was observed for bisphenol A, which was detected in concentrations up to 0.5 μg/L in the final recycled water. © 2010 Elsevier B.V. All rights reserved.
AlTaee, A & Sharif, AO 2011, 'Alternative design to dual stage NF seawater desalination using high rejection brackish water membranes', Desalination, vol. 273, no. 2-3, pp. 391-397.
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Dual stage NF membrane desalination process was proposed as an alternative approach to RO seawater desalination. Despite of being cheaper than RO desalination, dual stage NF process is not commercially applied yet due to the low overall recovery rate. In an attempt to increase the process recovery rate and to reduce the operation complicity, brackish water RO membrane was used instead of NF in the second stage. ROSA software was used in this study to verify the applicability and cost-effectiveness of the NF-BW dual stage desalination process. Similarly to dual stage NF desalination process, an NF membrane was used in the first stage and BW membrane in the second stage. Permeate from NF membrane was used as a feed into the BW membranes. The effect of membrane type and seawater salinity on the process performance was investigated. For any given recovery rate and seawater salinity, the simulation results showed that the overall cost of NF-NF was slightly lower than the NF-BW process but that was on the cost of higher permeate TDS. For instance, at 43,000mg/l feed salinity the difference in the specific power consumption between NF-NF and NF-BW process was 0.38kWh/m3. The permeate TDS was 125mg/l for NF-BW and 1030mg/l for NF-NF process. The difference in the permeate TDS between NF-NF and NF-BW process increased with increasing the feed salinity. In dual stage NF process, a low permeate was achieved at low recovery rate. For example, at 43,000mg/l feed salinity the permeate TDS from dual stage NF process was 359mg/l when the overall recovery rate was 22%. It was also found that the effect of BW membrane type on the process efficiency was insignificant. Finally, the energy requirements of NF-NF and NF-BW were compared to a single stage RO desalination process. The specific power consumption at 43,000mg/l feed salinity was 4.58kWh/m3, 4.2kWh/m3 and 3.86kWh/m3 for RO, NF-BW and NF-NF process respectively. © 2011 Elsevier B.V.
Amarjargal, A, Tijing, LD & Kim, CS 2011, 'One-pot synthesis of silver-titanium dioxide nanocomposites using ethylene glycol medium and their antibacterial properties', Digest Journal of Nanomaterials and Biostructures, vol. 6, no. 4, pp. 1957-1965.
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We report here for the first time a one-pot simultaneous synthesis and antibacterial properties of Ag-TiO2 nanocomposites via ethylene glycol medium. The salient features of this method include simple operation, large scale production and one medium (solvent) to produce two different nanoparticles. Clusters of Ag and TiO2 nanoparticles with an average size of 20 - 30 nm and narrow size distribution are formed after annealing at 400 and 500 oC. The annealed Ag-TiO2 nanoparticles show excellent antibacterial properties under visible-light irradiation.
Anbazhagan, P, Buddhima, I & Amarajeevi, G 2011, 'Characterization of Clean and Fouled Rail Track Ballast Subsurface Using Seismic Surface Survey Method: Model and Field Studies', Journal of Testing and Evaluation, vol. 39, no. 5, pp. 831-841.
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Abstract The efficiency of track foundation material gradually decreases due to insufficient lateral confinement, ballast fouling, and loss of shear strength of the subsurface soil under cyclic loading. This paper presents characterization of rail track subsurface to identify ballast fouling and subsurface layers shear wave velocity using seismic survey. Seismic surface wave method of multi-channel analysis of surface wave (MASW) has been carried out in the model track and field track for finding out shear wave velocity of the clean and fouled ballast and track subsurface. The shear wave velocity (SWV) of fouled ballast increases with increase in fouling percentage, and reaches a maximum value and then decreases. This character is similar to typical compaction curve of soil, which is used to define optimum and critical fouling percentage (OFP and CFP). Critical fouling percentage of 15 % is noticed for Coal fouled ballast and 25 % is noticed for clayey sand fouled ballast. Coal fouled ballast reaches the OFP and CFP before clayey sand fouled ballast. Fouling of ballast reduces voids in ballast and there by decreases the drainage. Combined plot of permeability and SWV with percentage of fouling shows that after critical fouling point drainage condition of fouled ballast goes below acceptable limit. Shear wave velocities are measured in the selected location in the Wollongong field track by carrying out similar seismic survey. In-situ samples were collected and degrees of fouling were measured. Field SWV values are more than that of the model track SWV values for the same degree of fouling, which might be due to sleeper’s confinement. This article also highlights the ballast gradation widely followed in different countries and presents the comparison of Indian ballast gradation with international gradation standards. Indian ballast contains a coarser particle size when compared to other countries. The upper ...
Anbazhagan, P, Lijun, S, Buddhima, I & Cholachat, R 2011, 'Model track studies on fouled ballast using ground penetrating radar and multichannel analysis of surface wave', Journal of Applied Geophysics, vol. 74, no. 4, pp. 175-184.
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Ansari, Y, Merifield, R, Yamamoto, H & Sheng, D 2011, 'Numerical analysis of soilbags under compression and cyclic shear', Computers and Geotechnics, vol. 38, no. 5, pp. 659-668.
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Aryal, R, Baral, B, Vigneswaran, S, Naidu, R & Loganathan, P 2011, 'Seasonal influence on urban dust PAH profile and toxicity in Sydney, Australia', WATER SCIENCE AND TECHNOLOGY, vol. 63, no. 10, pp. 2238-2243.
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Road dust is one of the major threats to the urban environment due to wash-off of dust to the surrounding catchments during wet weather period. The dust contains wide range of toxic contaminants such as heavy metals, polycyclic aromatic hydrocarbons (PAHs) and endocrine disrupting chemicals. Among the toxic contaminants, PAHs are of environmental concern due to their potential carcinogenic and mutagenic effect besides endocrine disruptive behaviour. Eighteen road dust samples from Sydney were collected in different time periods for a year and analysed for 16 US EPA PAHs. Total PAHs content range in the dust was 9-105 μg/g. Total and individual PAH contents were highest in the finest size fraction (<75 μm) and in winter compared to the other seasons. The PAH profiles in the different particle sizes were similar but different between the four seasons. The concentrations of higher molecular weight PAHs (4- and 5-rings) were much greater than the concentrations of lower molecular weight PAHs (2- and 3-rings). Toxicity equivalency factor application showed that the longer the dry weather period the higher the total PAHs content and toxicity in the dust. © IWA Publishing 2011.
Aryal, R, Kandasamy, J, Vigneswaran, S, Naidu, R & Lee, SH 2011, 'Review of stormwater quality, quantity and treatment methods part 1: Stormwater quantity modelling', Environmental Engineering Research, vol. 16, no. 4, pp. 71-78.
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A review of stormwater quantity and quality in the urban environment is presented. The review is presented in three parts. The first part reviews the mathematical methods for stormwater quantity and has been undertaken by examining a number of stormwater models that are in current use. The important feature of models, their applications, and management has been discussed. Different types of stormwater management models are presented in the literatures. Generally, all the models are simplified as conceptual or empirical depending on whether the model is based on physical laws or not. In both cases if any of the variables in the model are regarded as random variables having a probability distribution, then the model is stochastic model. Otherwise the model is deterministic (based on process descriptions). The analytical techniques are presented in this paper.
Aryal, R, Vigneswaran, S & Kandasamy, J 2011, 'Application of Ultraviolet (UV) Spectrophotometry in the Assessment of Membrane Bioreactor Performance for Monitoring Water and Wastewater Treatment', Applied Spectroscopy, vol. 65, no. 2, pp. 227-232.
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Ultraviolet (UV) spectroscopy has been widely used in monitoring water and wastewater treatment. In this study UV spectroscopy was used to investigate fouling development on the membrane surface of membrane bioreactors. The chemistry of mixed liquor present in the membrane bioreactor and the foulant deposited on the membrane surface was compared by analyzing the UV spectra. The mixed liquor showed different spectra than did the foulant. The foulant spectra showed a shift in absorbance peaks with operation time. The particle size distribution (<450 nm) was also examined to explain the UV fingerprints.
Aryal, R, Vigneswaran, S, Loganathan, P, Kandasamy, J & Mohammed, T 2011, 'Hydrous iron oxide for removal of inorganic contaminants in simulated stormwater: A batch sorption kinetics study', KOREAN JOURNAL OF CHEMICAL ENGINEERING, vol. 28, no. 8, pp. 1706-1712.
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Urban stormwater runoff, which consists of inorganic and organic contaminants, is a major source of pollutants to receiving waters and therefore they need to be removed. Simultaneous removal of contaminants, Cd2+, Cu2+, Ni2+, Zn2+ (heavy metal cations), and SeO42- (oxyanion) from a simulated stormwater by a hydrous ferric oxide (HFO) was studied in batch and column sorption experiments. In the batch experiment the rate of sorption of the ions was rapid at the beginning and reached equilibrium in approximately 300 min. The amounts of ions sorbed were proportionate to the respective initial concentration of the ions added to the HFO. Cluster analysis showed that all heavy metals had similar sorption behavior, whereas Se had a distinctly different sorption process. Of the three different kinetic models tested the pseudo-first order kinetic model fitted the data the best. The column experimental results beyond 180 min were consistent with those of the batch experiment that the removal efficiencies of the ions were in proportion to the ion concentration in the feed. Below 180 min, Cu appeared to be preferentially removed than Zn. © 2011 Korean Institute of Chemical Engineers, Seoul, Korea.
Atabani, AE, Badruddin, IA, Mekhilef, S & Silitonga, AS 2011, 'A review on global fuel economy standards, labels and technologies in the transportation sector', Renewable and Sustainable Energy Reviews, vol. 15, no. 9, pp. 4586-4610.
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Atallah, SS, El Saliby, I, Baalbaki, R & Talhouk, SN 2011, 'Effects of different irrigation, drying and production scenarios on the productivity, postharvest quality and economic feasibility of Origanum syriacum, a species typically over-collected from the wild in Lebanon', Journal of the Science of Food and Agriculture, vol. 91, no. 2, pp. 337-343.
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Background: The potential of Origanum syriacum L. to become a cultivated crop in Lebanon rather than being harvested from the wild was investigated at the production, postharvest and economic levels. Three irrigation schemes were tested on growth paramet
Bjarnadottir, S, Li, Y & Stewart, MG 2011, 'A probabilistic-based framework for impact and adaptation assessment of climate change on hurricane damage risks and costs', Structural Safety, vol. 33, no. 3, pp. 173-185.
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This paper presents a probabilistic-based framework to assess the potential hurricane risks to residential construction under various wind speed change scenarios due to potential climate change. Every year hurricane (cyclone) hazards cause extensive economic losses and social disruption around the world. Annual hurricane damage in the United States (US) is around $6 billion in recent years. Hurricane intensity or/and frequency may change due to the increase in sea surface temperature as a result of climate change. Implications of the changing hazard patterns on hurricane risk assessment warrants an investigation to evaluate the potential impact of climate change. The framework includes probabilistic models of hurricane occurrence and intensity and conditional damage state probabilities (vulnerability model) for typical residential construction in the US, and an assessment of the cost-effectiveness of various climate change adaptation strategies. A case study of Miami-Dade County, Florida is presented to illustrate the framework under various scenarios of change in maximum annual wind speed over 50. years. Demographic information, such as median house value and changes in house numbers, and distribution of houses on different exposure, is used to estimate the time-dependent probable damage with or without possible climate change induced change in wind speed. This study shows that climate change may have a substantial impact on the damage and loss estimation in coastal areas, and that certain adaptation strategies can cost effectively decrease the damage, even if the wind speed does not change. © 2011 Elsevier Ltd.
Bjarnadottir, S, Li, Y & Stewart, MG 2011, 'Social vulnerability index for coastal communities at risk to hurricane hazard and a changing climate', Natural Hazards, vol. 59, no. 2, pp. 1055-1075.
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This paper presents the development of the Coastal Community Social Vulnerability Index (CCSVI) in order to quantify the social vulnerability of hurricane-prone areas under various scenarios of climate change. The 2004-2005 Atlantic hurricane seasons is estimated to have caused $150 billion dollars in damages, and in recent years, the annual hurricane damage in the United States is estimated at around $6 billion. Hurricane intensity or/and frequency may change due to the increase in sea surface temperature as a result of climate change. Climate change is also predicted to cause a rise in sea levels, potentially resulting in higher storm surges. The CCSVI combines the intensity of hurricanes and hurricane-induced surge to create a comprehensive index that considers the effects of a changing climate. The main contributing factors of social vulnerability (such as race, age, gender, and socioeconomic status) in hurricane-prone areas are identified through a principal components analysis. The impact of social characteristics on the potential hurricane damage under various scenarios of climate change are evaluated using Miami-Dade County, Florida, as a case study location. This study finds that climate change may have a significant impact on the CCSVI. © 2011 Springer Science+Business Media B.V.
Bolch, T, Peters, J, Yegorov, A, Pradhan, B, Buchroithner, M & Blagoveshchensky, V 2011, 'Identification of potentially dangerous glacial lakes in the northern Tien Shan', Natural Hazards, vol. 59, no. 3, pp. 1691-1714.
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Bourouni, K, Ben M’Barek, T & Al Taee, A 2011, 'Design and optimization of desalination reverse osmosis plants driven by renewable energies using genetic algorithms', Renewable Energy, vol. 36, no. 3, pp. 936-950.
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Renewable energy sources (RES) for powering desalination processes is a promising option especially in remote and arid regions where the use of conventional energy is costly or unavailable. Reverse Osmosis (RO) is one of the most suitable desalination processes to be coupled with different renewable energy sources such as solar and wind.
If RES/RO systems are optimally designed, some combinations can be cost effective and reliable. However, the design of such systems is complex because of uncertain renewable energy supplies, load demands and the non-linear characteristics of some components.
In such system, different scenarios can be suggested; i.e combinations of PV panels, type and number of batteries, type and number of turbines, etc. Therefore, it is difficult to determine the optimal configuration with classical techniques. The development of a tool to integrate all parameters involved and compare between the possible scenarios is very important.
This paper presents a new model based on the Genetic Algorithms allowing the generation of several individuals (possible solutions) for coupling small RO unit to RES. A particular interest is focused on the hybrid systems (PV/WIND/Batteries/RO). The objective function to minimize corresponds to the total water cost (Capital cost plus Operational costs).
Finally, a case study of PV/RO unit, installed since 2007 in Ksar Ghilène village in southern Tunisia, is presented.
Carpi, LC, Rosso, OA, Saco, PM & Ravetti, MG 2011, 'Analyzing complex networks evolution through Information Theory quantifiers', Physics Letters A, vol. 375, no. 4, pp. 801-804.
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Castel, A & François, R 2011, 'Modeling of steel and concrete strains between primary cracks for the prediction of cover-controlled cracking in RC-beams', Engineering Structures, vol. 33, no. 12, pp. 3668-3675.
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Castel, A, Coronelli, D, François, R & Cleland, D 2011, 'Modelling the Stiffness Reduction of Corroded Reinforced Concrete Beams after Cracking', MODELLING OF CORRODING CONCRETE STRUCTURES, vol. 5, pp. 219-230.
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Castel, A, Coronelli, D, Vu, NA & François, R 2011, 'Structural Response of Corroded, Unbonded Posttensioned Beams', Journal of Structural Engineering, vol. 137, no. 7, pp. 761-771.
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Chanan, AP, Ghetti, IB & Kandasamy, JK 2011, 'Challenges of managing coastal areas through climate change', PROCEEDINGS OF THE INSTITUTION OF CIVIL ENGINEERS-MUNICIPAL ENGINEER, vol. 164, no. 2, pp. 83-88.
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In Australia the strongest natural fluctuation of climate from year to year is the El Niño southern oscillation. La Niña years are associated with an increased probability of wetter and cooler conditions, whereas El Niño years are drier and hotter then normal. For an urbanised coastal council such as Kogarah there are a number of impacts associated with climate change. For instance, the risk of flooding may be increased due to more intense rainfalls coupled with rising sea levels. Coastal councils may also experience increased coastal flooding and erosion due to increased storm surges and rising sea levels. Water restrictions are already in place due to severe droughts, and it is predicted that councils will have limited water supply available for the irrigation needed to provide parks and well-maintained sporting facilities for the community. Given that the science of climate change is not an exact science there are obvious technical and sociopolitical challenges to be addressed. This paper shares Kogarah Council's experiences in dealing with these challenges and provides a snapshot of programmes currently being implemented in response to climate change. By investing in proactive measure to reduce risk and vulnerability it is possible to build resilience to climate change.
Chanan, AP, Kandasamy, J & Vigneswaran, S 2011, 'Role of case study research in training the renaissance water engineer', Global Journal of Engineering Education, vol. 13, no. 3, pp. 110-116.
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Contemporary water management challenges around Australia highlight water engineers' inability to understand the community's needs. Developing new technologies is not enough. Implementation of these technologies can only take place if the engineers understand the motives and desires of people that are related to the new technology and the effects on the community as a whole. Renaissance water engineers who are able to go beyond their own technical specialty and understand the broader implications of the technological solutions they develop, are needed to solve Australia's water problems. Our ability to produce such engineers depends on our ability to first prepare renaissance engineering academics within our higher education institutions. It is, therefore, imperative to re-examine current practices in engineering PhDs. The engineering discipline is urged to embrace the case study research approach as a vital means of training renaissance water engineers. © WIETE 2011.
Chanan, AP, Vigneswaran, S, Kandasamy, J & Simmons, B 2011, 'Lessons for a viable water recycling industry', PROCEEDINGS OF THE INSTITUTION OF CIVIL ENGINEERS-WATER MANAGEMENT, vol. 164, no. 5, pp. 213-219.
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The platform on which the labour government came to power in Australia in November 2007 included a policy of setting a national wastewater recycling target of 30% by the year 2015. A similar target-based approach was followed by the solid waste recycling industry in Australia the policy of which focused on supply and did not adequately acknowledge the price competitiveness of the product and its demand. This paper highlights the lessons from the solid waste recycling industry and applies them to the water recycling sector. A sound water pricing regime that reflects the true costs of water and a competitive water industry is offered as a better policy alternative to setting recycling targets.
Chang, C-Y, Tanong, K, Xu, J & Shon, H 2011, 'Microbial community analysis of an aerobic nitrifying-denitrifying MBR treating ABS resin wastewater', BIORESOURCE TECHNOLOGY, vol. 102, no. 9, pp. 5337-5344.
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A two-stage aerobic membrane bioreactor (MBR) system for treating acrylonitrile butadiene styrene (ABS) resin wastewater was carried out in this study to evaluate the system performance on nitrification. The results showed that nitrification of the aerobic MBR system was significant and the highest TKN removal of approximately 90% was obtained at hydraulic retention time (HRT) 18 h. In addition, the result of nitrogen mass balance revealed that the percentage of TN removal due to denitrification was in the range of 8.7â19.8%. Microbial community analysis based on 16s rDNA molecular approach indicated that the dominant ammonia oxidizing bacteria (AOB) group in the system was a b-class ammonia oxidizer which was identified as uncultured sludge bacterium (AF234732). A heterotrophic aerobic denitrifier identified as Thauera mechernichensis was found in the system. The results indicated that a sole aerobic MBR system for simultaneous removals of carbon and nitrogen can be designed and operated for neglect with an anaerobic unit.
Chen, Z, Ngo, H, Guo, W, Wang, XC & Luo, L 2011, 'Probabilistic Assessment of Recycled Water Schemes in Australia Using MATLAB Toolbox', Journal of Water Sustainability, vol. 1, no. 3, pp. 333-344.
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Hundreds of recycled water schemes have been successfully established in Australia. However, water quality and risks on human health and the environment associated with particular end uses (e.g. irrigation, industrial uses, non-potable urban uses, groundwater recharges, indirect and direct potable reuses) are still of great concern which can limit the application and extension of recycled water. This study analyses representative recycled water schemes in Australia with regard to the sources and corresponding risks of recycled water, risk assessment approaches as well as practical risk control methods towards various end uses. To quantify the risks, this study proposes a probabilistic assessment approach for existing and future water recycling schemes. With the assistance of MATLAB toolbox, the model was able to fit observed data to probability distribution functions (PDFs) and express the percent removal in PDF rather than point values. This approach could be helpful in quantifying risk or percent removal of potential hazards which involve a degree of variability and randomness. The analytical results, when couple with other environmental assessment tools are convinced to be useful for integrated water planning and management in Australia.
Chiemchaisri, W, Chiemchaisri, C, Dumrongsukit, C, Threedeach, S, Ngo, HH & Vigneswaran, S 2011, 'Removal of water-borne microorganisms in floating media filter-microfiltration system for water treatment', BIORESOURCE TECHNOLOGY, vol. 102, no. 9, pp. 5438-5443.
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Floating plastic media pre-filter (PP) in combination with microfiltration membrane (MF) was applied to the removal of water-borne microorganism from surface water. The system was operated with and with-out coagulant addition. Jar-test results suggested
Ching, YC, Ching, YC, Kalam, A & Iskandar, IY 2011, 'Comparison Use of Suspended Cell System and Polyurethane Base Immobilized Cell System in Biological Treatment of Wastewater', RESEARCH JOURNAL OF CHEMISTRY AND ENVIRONMENT, vol. 15, no. 2, pp. 849-855.
Chong, WT, Naghavi, MS, Poh, SC, Mahlia, TMI & Pan, KC 2011, 'Techno-economic analysis of a wind–solar hybrid renewable energy system with rainwater collection feature for urban high-rise application', Applied Energy, vol. 88, no. 11, pp. 4067-4077.
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Chowdhury, MSN, Hossain, MS, Das, NG & Barua, P 2011, 'Environmental variables and fisheries diversity of the Naaf River Estuary, Bangladesh', Journal of Coastal Conservation, vol. 15, no. 1, pp. 163-180.
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El Saliby, I, Erdei, L, Shon, HK & Kim, J-H 2011, 'Development of visible light sensitive titania photocatalysts by combined nitrogen and silver doping', JOURNAL OF INDUSTRIAL AND ENGINEERING CHEMISTRY, vol. 17, no. 2, pp. 358-363.
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In this study we present the effects of non-metal (nitrogen) and metal/non-metal (silver/nitrogen) dopants on titanium dioxide (TiO2) in synthesising visible-light reactive photocatalysts. Nanopowders of TiO2-N and TiO2-NâAg were synthesised using a simple procedure at room temperature. For nitrogen doping, a dispersion of Degussa P-25 was treated with ammonium hydroxide. The obtained modified catalyst was further treated with silver nitrate powder to facilitate silver-nitrogen co-doping. The produced catalysts were characterised using X-ray diffraction, X-ray photoelectron spectroscopy, and specific surface area measurements. Scanning electron microscopy/energy dispersive X-ray and transmission electron microscopy were adapted to detect changes in the morphology and in the chemical composition of synthesised catalysts. The results show that both the morphology and appearance of catalysts were modified to yield nanopowders of yellowish color and relatively high specific surface area. Methylene blue (MB) dye was used as a model aquatic contaminant in 23 mg/L concentration to study the performance of these novel photocatalysts in an aerobic mixed batch reactor system under white light irradiation. Both nitrogen and nitrogen-silver co-doping lead to visible light sensitivity and the new catalysts showed remarkable activities in the decolorisation of MB.
El Saliby, I, Erdei, L, Shon, HK, Kim, JB & Kim, J-H 2011, 'Preparation and characterisation of mesoporous photoactive Na-titanate microspheres', CATALYSIS TODAY, vol. 164, no. 1, pp. 370-376.
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Mesoporous Na-titanate microspheres were fabricated by a simple low temperature hydrothermal synthesis. Microsphereswereobtained after treating TiO2 (Degussa P-25) with a mixture of sodium hydroxide (NaOH) and hydrogen peroxide (H2O2) at 25â¦C and 80 â¦C. The as-prepared powders were characterised by X-ray diffraction, N2 adsorptionâdesorption measurements and scanning electron microscope/energy dispersive X-ray spectroscopy. The as-prepared microspheres were calcined at 550 â¦C to investigate the effect of calcination on morphology and characteristics. Microspheres were tested for the adsorption and photodecomposition of methylene blue (MB) under ultraviolet light. The results revealed that microspheres with average diameter of 700nmwere formed by self-assembly of tiny TiO2 nanoparticles during the reaction at 25 â¦C, whereas spherical aggregation of nanofibres was detected in powders produced at 80 â¦C. Calcination of samples had low impact on morphology, adsorption and photocatalytic degradation of MB. These novel materials are effective adsorbents of MB, and also capable of its photodecolorisation.
El Saliby, I, Shon, HK, Kandasamy, J & Kim, J-H 2011, 'Synthesis, characterisation and separation of photoreactive Hydrogen-titanate nanofibrous channel', Separation and Purification Technology, vol. 77, no. 2, pp. 202-207.
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Australia is the world's largest wool producing country, accounting for about 25â30% of world production. As a biotemplate, we explored the possibility of using wool to produce micro-channel of Hydrogentitanate nanofibres through morphology transcription of wool microfibres. Hydrothermal method was adopted to synthesise titanate nanofibres. A facile method of impregnation followed by incineration at 600 â¦C was utilised to prepare the nanofibrous channel. Anatase undoped nanofibrous (average nanofibre diameter = 44 nm) channel of around 50min length and an average diameter of 9.5mwere obtained. The photocatalytic activity of nanofibrous channel was monitored under UV irradiation for the decomposition of humic acid in aqueous solution using an aerobic batch reactor system. The photodegradation results showed that UV254 absorbing moeities and DOC were respectively reduced by 82% and 66% after 3 h of photoreaction at 1 g/L catalyst load. The novel nanofibrous channel could be easily separated from the aqueous suspension by sedimentation after the end of the photocatalytic reaction.
Fang, F, Ni, B, Li, W, Sheng, G & Yu, H 2011, 'A simulation-based integrated approach to optimize the biological nutrient removal process in a full-scale wastewater treatment plant', Chemical Engineering Journal, vol. 174, no. 2-3, pp. 635-643.
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Fatahi, B, Engelbert, D, Mujic, S & Khabbaz, H 2011, 'Effects of preloading on soft clay improvement using Deep Soil Mixing', Australian Geomechanics Journal, vol. 46, no. 3, pp. 63-71.
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Poor performing soils, particularly soft clays, are more prevalent around lakes and coastal environments, where demand for construction is generally higher. It is therefore critical that suitable ground improvement techniques be developed and refined to ensure these sites perform satisfactorily under applied structural loads. There is a clear trend in geotechnical construction to further develop technologies such as Deep Soil Mixing (DSM), using cement, lime, fly ash or bottom ash, with an aim to improve the mechanical properties of problematic soils. In this study, the influence of surcharge (10 kPa to 120 kPa) applied during curing on soil-cement columns is investigated using two different clay types, namely kaolinite and bentonite. Preload provides confinement and pre-compression during curing, which in turn increases the bearing capacity of the treated ground. The results of unconfined compressive strength tests are analysed to illustrate how the mechanical properties of the clays composed of differing cement content are influenced under varying surcharges applied instantly after mixing. The results indicate that mechanical properties of cement treated soft clays, including strength and stiffness can be enhanced through the application of surcharge immediately after construction, during the curing phase. This could potentially provide a cost effective and environmentally friendly alternative by reducing the required cement content being added to soil to achieve a given strength.
Fatahi, B, Khabbaz, H & Ho, HL 2011, 'Effects of geotextiles on drainage performance of ballasted rail tracks', Australian Geomechanics Journal, vol. 46, no. 4, pp. 91-102.
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Naturally soft soils are mostly found around coastal regions, where the construction of ballasted rail tracks is required to have a more thorough consideration regarding filtration. Any poor filter design on weak ground inevitably leads to a critical change in ballast characteristics. It is noticeable that such a change results in several issues including significant migration of finer particles about the subballast-subgrade interface and the deficiency of subballast filtration. These problems eventually reduce the drainage ability of the rail sub-system and may cause severe damage which can only be remedied by frequent and costly track maintenance. It is therefore important that geosynthetics such as geotextiles are introduced to the rail track system as an additional filter layer, which is able to retain the desirable filtering characteristics. This paper investigates the impact of non-woven geotextiles on filtration behaviour of subballast in the laboratory, while adopting different granular filter (subballast) thicknesses varying from 0 mm to 50 mm. The research findings demonstrate a notable difference in the cumulative fine loss per unit volume within a given period of time between two distinctive tests - with and without geotextiles, thus emphasising the beneficial application of this geosynthetic material. Empirical estimation of permeability and properties of subballast, including grading curves after testing, are carefully carried out and the results are presented in this paper. The results indicate that the thickness of granular subballast can be significantly reduced by including geotextiles. This paper, in turn, evaluates the potential combination of the track substructure and geotextiles to achieve the optimum filter design and more importantly, alleviate the cost of track maintenance.
Fatahi, B, Khabbaz, SH & Basack, S 2011, 'Effects of salinity and sand content on liquid limit and hydraulic conductivity', Australian Geomechanics Journal, vol. 46, no. 1, pp. 67-76.
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Soil conditions of construction sites have become worse than ever due to the overpopulation in the metropolitan areas throughout the world. Likewise, the prevention of environmental risks due to individual activities is one of the most important subjects in the geo-environmental problems. Saline soils may induce several problems in geotechnical engineering projects such as infrastructure embankments, road construction and clay liners. Effect of the various concentrations of sodium chloride (NaCl) on several different soils including bentonite, kaolinite and fine sand mixtures has been evaluated. In addition, influence of salinity and the period of submergence on the hydraulic conductivity of soil samples collected from a certain area of east coast of India was investigated. The results show that the liquid limit of the mixtures generally decreases with an increase in the salt concentration. Liquid limit decreased significantly with an increase in NaCl concentration up to a certain level. However, a further increase in the concentration does not induce any significant decrease in liquid limit. Furthermore, the soil hydraulic conductivity increase with the salt concentration and with increase in the period of submergence, the hydraulic conductivity of the soil increases asymptotically.
Fredlund, DG, Sheng, D & Zhao, J 2011, 'Estimation of soil suction from the soil-water characteristic curve', Canadian Geotechnical Journal, vol. 48, no. 2, pp. 186-198.
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Soil-water characteristic curves (SWCCs) are routinely used for the estimation of unsaturated soil property functions (e.g., permeability functions, water storage functions, shear strength functions, and thermal property functions). This paper examines the possibility of using the SWCC for the estimation of in situ soil suction. The paper focuses on the limitations of estimating soil suctions from the SWCC and also suggests a context under which soil suction estimations should be used. The potential range of estimated suction values is known to be large because of hysteresis between drying and wetting SWCCs. For this, and other reasons, the estimation of in situ suctions from the SWCC has been discouraged. However, a framework is suggested in this paper for estimating the median value for in situ soil suction along with a likely range of soil suction values (i.e., maximum and minimum values). The percentage error in the estimation of soil suction from the SWCC is shown to be lowest for sand soils and highest for clay soils.
Gao, W, Wu, D, Song, C, Tin-Loi, F & Li, X 2011, 'Hybrid probabilistic interval analysis of bar structures with uncertainty using a mixed perturbation Monte-Carlo method', Finite Elements in Analysis and Design, vol. 47, no. 7, pp. 643-652.
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This paper presents a mixed perturbation Monte-Carlo method for static and reliability analysis of structural systems with a mixture of random and interval parameters/loadings. Using a combination of the Taylor expansion, matrix perturbation theory and random interval moment method, the expressions for the mean value and standard deviation of random interval structural responses are developed. The Monte-Carlo simulation method is employed to determine the lower and upper bounds of the mean values and standard deviations of structural displacements and stresses. The structural reliability is not a deterministic value but an interval as the structural stress responses are random interval variables. The lower and upper bounds of probability of failure and reliability of structural elements and systems are investigated based on the first-order second-moment reliability method and interval approach. Three numerical examples are used to illustrate the effectiveness of the proposed method. © 2011 Elsevier B.V.
Gao, Y, Fang, J, Zhang, J, Ren, L, Mao, Y, Li, B, Zhang, M, Liu, D & Du, M 2011, 'The impact of the herbicide atrazine on growth and photosynthesis of seagrass, Zostera marina (L.), seedlings', Marine Pollution Bulletin, vol. 62, no. 8, pp. 1628-1631.
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Geng, X, Indraratna, B & Rujikiatkamjorn, C 2011, 'Effectiveness of partially penetrating vertical drains under a combined surcharge and vacuum preloading', Canadian Geotechnical Journal, vol. 48, no. 6, pp. 970-983.
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This paper considers the consolidation of a layer of clay in which partially penetrating prefabricated vertical drains (PVDs) are used in conjunction with a combined surcharge and vacuum preloading. Analytical solutions for partially penetrating PVDs are derived by considering vacuum pressure (suction), time-dependent embankment surcharge, well resistance, and smear zone. Three-dimensional seepage with a virtual vertical drain is assumed to reflect real seepage into the soil beneath the tip of a PVD. Analytical solutions were then used to examine the length of the vertical drain and vacuum pressure on soft clay to determine the consolidation time and degree of consolidation, associated settlement, and distribution of suction along the drain. The proposed solutions are then employed to analyse a case history. Finally, an appropriate PVD length in relation to clay thickness and drain spacing is recommended for various loading patterns.
Grover, DP, Balaam, J, Pacitto, S, Readman, JW, White, S & Zhou, JL 2011, 'Endocrine disrupting activities in sewage effluent and river water determined by chemical analysis and in vitro assay in the context of granular activated carbon upgrade', Chemosphere, vol. 84, no. 10, pp. 1512-1520.
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As part of endocrine disruption in catchments (EDCAT) programme, this work aims to assess the temporal and spatial variations of endocrine disrupting chemicals (EDCs) in River Ray, before and after the commissioning of a full-scale granular activated carbon (GAC) plant at a sewage treatment works (STW). Through spot and passive sampling from effluent and river sites, estrogenic and anti-androgenic activities were determined by chemical analysis and in vitro bio-assay. A correlation was found between chemical analyses of the most potent estrogens (estrone (E1), 17β-estradiol (E2), 17α-ethinylestradiol (EE2)) and yeast estrogen screen (YES) measurement, both showing clearly a reduction in estrogenic activity after the commissioning of the GAC plant at the STW. During the study period, the annual average concentrations of E1, E2 and EE2 had decreased from 3.5ngL -1, 3.1ngL -1 and 0.5ngL -1 to below their limit of detection (LOD), respectively, with a concentration reduction of at least 91%, 81% and 60%. Annual mean estrogenic activity measured by YES of spot samples varied from 1.9ngL -1 to 0.4ngL -1 E2 equivalent between 2006 and 2008 representing a 79% reduction. Similarly, anti-androgenic activity measured by yeast anti-androgen screen (anti-YAS) of spot samples was reduced from 148.8 to 22.4μgflutamideL -1, or by 85%. YES and anti-YAS values were related to each other, suggesting co-existence of both types of activities from chemical mixtures in environmental samples. The findings confirm the effectiveness of a full-scale GAC in removing both estrogenic and anti-androgenic activities from sewage effluent. © 2011 Elsevier Ltd.
Grover, DP, Zhou, JL, Frickers, PE & Readman, JW 2011, 'Improved removal of estrogenic and pharmaceutical compounds in sewage effluent by full scale granular activated carbon: Impact on receiving river water', Journal of Hazardous Materials, vol. 185, no. 2-3, pp. 1005-1011.
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Sewage effluents are widely recognised as the main source of emerging contaminants, such as endocrine disrupting chemicals (EDCs) and pharmaceuticals in surface waters. A full-scale granular activated carbon (GAC) plant has been installed as an advanced technology for the removal of these contaminants, in a major sewage treatment works (STW) in South-West England as part of the UK National Demonstration Programme for EDCs. This study presented for the first time, an assessment of the impact of a recently commissioned, post-tertiary GAC plant in the removal of emerging contaminants in a working STW. Through regular sampling followed by solid-phase extraction and analysis by liquid chromatography-tandem mass spectrometry (LC-MS/MS), a significant reduction in the concentrations of steroidal estrogens was observed (>43-64%). In addition, significant reductions were observed for many of the pharmaceutical compounds such as mebeverine (84-99%), although the reduction was less dramatic for some of the more widely used pharmaceuticals analysed, including carbamazepine and propranolol (17-23%). © 2010 Elsevier B.V.
Guo, W, Ngo, HH, Wu, Z, Hu, AYJ & Listowski, A 2011, 'Application of bioflocculant and nonwoven supporting media for better biological nutrient removal and fouling control in a submerged MBR', Sustainable Environment Research, vol. 21, no. 1, pp. 53-58.
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The study aims at modifying a submerged membrane bioreactor (SMBR) with attached-growth nonwoven media and a new green bioflocculant (GBF) (developed at Environmental Engineering R & D laboratory, University of Technology, Sydney) addition to treat a high strength domestic wastewater for reuse. The performance of the SMBR was evaluated in terms of organic and nutrient removal as well as membrane fouling control. The results indicated that the integrated SMBR system could eliminate more than 95% dissolved organic carbon and chemical oxygen demand from the influent. The system achieved 100% of nitrification during 60 d of operation. The denitrification was primarily based on conventional nitrification-denitrification process occurring in the anoxic zone. The total nitrogen removal efficiency and simultaneous nitrification and denitrification were 93 ± 3 and 96 ± 1% respectively. Although a relatively long solids retention time (50 d) were adopted, over 98% of total phosphorus in the influent was removed through biological phosphorus removal. The results also show that the addition of GBF could improve microbial activity and reduce membrane fouling. During the experiment, the transmembrane pressure developed marginally (4.5 kPa).
Guruprasad, B, Indraratna, B, Nghiem, LD & Regmi, G 2011, 'A neural network approach to predict the performance of recycled concrete used in permeable reactive barriers for the treatment of acidic groundwater', Quarterly Journal of Engineering Geology and Hydrogeology, vol. 44, no. 2, pp. 199-209.
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Hai, FI, Tadkaew, N, McDonald, JA, Khan, SJ & Nghiem, LD 2011, 'Is halogen content the most important factor in the removal of halogenated trace organics by MBR treatment?', Bioresource Technology, vol. 102, no. 10, pp. 6299-6303.
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Hashim, NH, Nghiem, LD, Stuetz, RM & Khan, SJ 2011, 'Enantiospecific fate of ibuprofen, ketoprofen and naproxen in a laboratory-scale membrane bioreactor', Water Research, vol. 45, no. 18, pp. 6249-6258.
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Ho, D, Vigneswaran, S, Ngo, HH, Shon, HK, Kandasamy, J, Chang, CY & Chang, JS 2011, 'Photocatalysis of trimethoprim (TRI) in water', Sustainable Environment Research, vol. 21, no. 3, pp. 149-154.
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The advantage of the use of photocatalysts to treat persistent organic pollutants (POP) was demonstrated with the decomposition of trimethoprim (TRI), an antibiotic most frequently detected in municipal wastewaters and surface waters. In this study, the oxidation process by UV/TiO2 was employed as an alternative to advanced oxidation process (AOP) to remove residual antibiotics from water. High concentrations of TRI were used to study the efficiency of photocatalysis. Both batch and continuous photoreactors were used. The decomposition of TRI by TiO2/UV photooxidation occurred gradually over time. On the other hand, with UV irradiation alone, the reduction of TRI mineralization was relatively small. The effect of light intensity showed there was no significant impact of UV light intensity on the degradation of TRI in the range of increasing intensities studied. The simulation using first-order kinetics provided a good fit with the experimental data. In the continuous system, the feed flow rate was adjusted to maximize the percentage of mineralization of targeted compounds inside the photoreactor. A lower flow rate, i.e., higher detention time, achieved higher percentage of TRI mineralization. The results indicated that TiO2/UV irradiation was effective in removing TRI.
Hokmabadi, AS, Fakher, A & Fatahi, B 2011, 'Seismic Strain Wedge Model for analysis of single piles under lateral seismic loading', Australian Geomechanics Journal, vol. 46, no. 1, pp. 31-41.
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One of the most effective methods of analysing a single pile and pile groups under lateral loading is Strain Wedge Model (SWM). SWM has a number of advantages in comparison with traditional p-y curves, but this model could traditionally only be used to analyse piles under monotonie loads. In the present paper, SWM has been modified to consider dynamic lateral loading. Based on this new method, called Seismic Strain Wedge Model (SSWM), a computer code has been developed for lateral analysis of piles. Using this computer code, some case studies have been analysed and the results show good agreement with test data. This paper introduces SSWM as a simple and powerful solution to analyse piles under lateral seismic loading.
HU, H 2011, 'Dynamic Modeling and Its Sliding Controller of MR Shock Absorber under Impact Load', Journal of Mechanical Engineering, vol. 47, no. 13, pp. 84-84.
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An MR shock absorber under impact load is investigated. A single-rod long-stroke impact absorber is developed. Based on Bingham model and its structure of MR damper under impact load, a dynamic model of MR damper under impact load is derived, which is composed of annular damping hole's friction damping force, coulomb damping force, inertia damping force, throttle damping force, structure additional damper force and other friction forces. By applying the least square algorithm, important parameters in the dynamic model are identified. Experimental results confirm the accuracy of the derived and fitted dynamic model. According to its strong nonlinearity, wide frequency range and high peak-value of acceleration characteristics of impact load, an output target tracer using sliding control strategy is designed and simulated on the basis of constructing hardware-in-the-loop platform. The control effects of three control strategies, namely, On-Off strategy, PID strategy and sliding mode control strategy, are compared and analyzed. The results show that the vibration peak value of MR impact absorber under sliding mode control strategy is reduced by 27.33%, and its piston stroke is reduced by 48.75%, thus being the most ideal control effect. ©2011 Journal of Mechanical Engineering.
Hu, Y, Wu, C, Lukaszewicz, M, Dragos, J, Ren, J & Haskett, M 2011, 'Characteristics of Confined Blast Loading in Unvented Structures', International Journal of Protective Structures, vol. 2, no. 1, pp. 21-43.
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Confined blast loading occurs in many scenarios and the effects of confined blast loading may result in more serious damage to buildings due to multiple shock reflections (Shi et al. 2009). However, spherical charges are assumed for all confined explosive-effects computations in modern standards for blast-resistant design such as UFC-3-340-02 (2008) and the soon-to-be published ASCE Standard for the Blast Protection of Buildings (ASCE forthcoming) without consideration of effects of charge shape on the distribution of reflected overpressure and impulse. As confinement is an aggravation factor of explosion effects, analysis and design of infrastructure under critical scenarios of confined blast loading should take the aggravation factor into consideration. This paper is to develop a numerical model for prediction of blast loads inside unvented structures as a result of variation of the charge shape, charge orientation, geometries and volumes of confined chambers. A finite element program, AUTODYN (Century Dynamics, 2003), is utilized extensively to generate a model which is capable of being calibrated with the experimental results conducted by Wu et al. (2010) in external conditions and by Zyskowski et al. (2004) in a confined small box. The calibrated AUTODYN model is then used to conduct parametric studies to analyze the effects of the variation of charge shape, charge orientation, chamber geometry and chamber volume on the peak reflected overpressure and impulse on the walls of the chamber. The quasi-static overpressure for fully confined blast loading is characterized and the simulated results are used to derive the relationships between the quasi-static overpressure and scaled distance for the fully confined blast loading. Discussion is made on characteristics of fully confined blast loading inside chambers.
Huang, M, Liu, Y & Sheng, D 2011, 'Simulation of yielding and stress–stain behavior of shanghai soft clay', Computers and Geotechnics, vol. 38, no. 3, pp. 341-353.
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Huang, Z, Chen, X, Yisgedu, T, Meyers, EA, Shore, SG & Zhao, J-C 2011, 'Ammonium Octahydrotriborate (NH4B3H8): New Synthesis, Structure, and Hydrolytic Hydrogen Release', Inorganic Chemistry, vol. 50, no. 8, pp. 3738-3742.
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Huang, Z, Chen, X, Yisgedu, T, Zhao, J-C & Shore, SG 2011, 'High-capacity hydrogen release through hydrolysis of NaB3H8', International Journal of Hydrogen Energy, vol. 36, no. 12, pp. 7038-7042.
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Husnawan, M, Masjuki, HH & Mahlia, TMI 2011, 'The interest of combining two additives with palm olein as selected lubricant components', Industrial Lubrication and Tribology, vol. 63, no. 3, pp. 203-209.
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PurposeThe purpose of this paper is to study the effect of palm olein, amine phosphate and 4‐nonyl phenoxy acetic acid (NPAA) added to a commercial lubricant in terms of tribological properties such as wear and coefficient of friction.Design/methodology/approachA tribological study on the lubrication performance of a lubricant‐based palm oil (PO) containing anti‐wear and antioxidant combined corrosion inhibitor additive was carried out using a universal sliding wear machine. In this experiment, amine phosphate and NPAA were selected as additive to be mixed with PO (palm olein) in several concentrations and commercial lubricant 20W‐50 for the tests. Various PO blended samples with additional 1 and 3 percent additive were used in this study. The experiments were performed under 252 rpm sliding speed for 2 h where the oil temperature reached 100°C.FindingsThe analysis showed that the average wear coefficient and the mean wear scar diameter (MWSD) which is normalized to the 1.4 KPa water pressure generates lower values for the PO containing additives than 100 percent PO, commercial lubricant and their blended. The coefficients of friction and wear were also lower for the samples with additives compared to other. To consolidate the result, viscosity of used samples is checked and shows the additives improved the viscosity stability. Finally, the overall study concluded that PO‐added additives have the potential to be one of the ingredients in effective lubricant oil.Research limitations/implicationsThe paper is limited to findings based on a Universal Sliding Machine Test under certain conditions. The tes...
Indraratna, B, Ngo, NT & Rujikiatkamjorn, C 2011, 'Behavior of geogrid-reinforced ballast under various levels of fouling', Geotextiles and Geomembranes, vol. 29, no. 3, pp. 313-322.
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This paper presents a study of how the interface between ballast and geogrid copes with fouling by coal fines. The stress-displacement behavior of fresh and fouled ballast, and geogrid reinforced ballast was investigated through a series of large-scale direct shear tests where the levels of fouling ranged from 0% to 95% Void Contamination Index (VCI), at relatively low normal stresses varying from 15 kPa to 75 kPa. The results indicated that geogrid increases the shear strength and apparent angle of shearing resistance, while only slightly reducing the vertical displacement of the composite geogrid-ballast system. However, when ballast was fouled by coal fines, the benefits of geogrid reinforcement decreased in proportion to the increasing level of fouling. A conceptual normalized shear strength model was proposed to predict this decrease in peak shear stress and peak angle of shearing resistance caused by coal fines at a given normal stress. © 2011.
Indraratna, B, Nguyen, VT & Rujikiatkamjorn, C 2011, 'Assessing the Potential of Internal Erosion and Suffusion of Granular Soils', Journal of Geotechnical and Geoenvironmental Engineering, vol. 137, no. 5, pp. 550-554.
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Indraratna, B, Rujikiatkamjorn, C, Ameratunga, J & Boyle, P 2011, 'Performance and Prediction of Vacuum Combined Surcharge Consolidation at Port of Brisbane', Journal of Geotechnical and Geoenvironmental Engineering, vol. 137, no. 11, pp. 1009-1018.
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Indraratna, B, Rujikiatkamjorn, C, Geng, X-Y, McIntosh, G & Kelly, R 2011, 'Soft Soils Improved by Prefabricated Vertical Drains: Performance and Prediction', Soils and Rocks, vol. 34, no. 4, pp. 379-388.
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The use of prefabricated vertical drains with vacuum preloading and surcharge preloading is now common practice and is proving to be one of the most effective ground improvement techniques known. The factors affecting its performance, such as the smear zone, the drain influence zone, and drain unsaturation, are discussed in this paper. In order to evaluate these effects a large scale consolidation test was conducted and it was found that the proposed Cavity Expansion Moreover, the procedure for converting an equivalent 2-D plane strain multi-drain analysis that considers the smear zone and vacuum pressure are also described. The conversion procedure was incorporated into finite element codes using a modified Cam-clay theory. Numerical analysis was conducted to predict excess pore pressure and lateral and vertical displacement. Three case histories are analyzed and discussed, including the sites of Muar clay (Malaysia), the Second Bangkok International Airport (Thailand), and the Sandgate railway line (Australia). The predictions were then compared with the available field data, which include settlement, excess pore pressure, and lateral displacement. Further findings verified that smear, drain unsaturation, and vacuum distribution can significantly influence consolidation so they must be modeled appropriately in any numerical analysis to obtain reliable predictions.
Indraratna, B, Su, L-J & Rujikiatkamjorn, C 2011, 'A new parameter for classification and evaluation of railway ballast fouling', Canadian Geotechnical Journal, vol. 48, no. 2, pp. 322-326.
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The physical condition of railway ballast should be regularly inspected and accordingly, ballast cleaning should be carried out to maintain the safe operation of a track. This paper reviews current methods commonly used for evaluating the degree of ballast fouling, and due to their limitations, a new parameter — “relative ballast fouling ratio”— is proposed. Categories of fouling based on the proposed method are derived from the particle gradation curves taken from past literature. Comparisons between these methods demonstrate that the newly proposed relative ballast fouling ratio would best represent the influence of the type and gradation of fouling material.
Ip, KH, Stuart, B, Ray, A & Thomas, P 2011, 'ESEM-EDS Investigation of the Weathering of a Heritage Sydney Sandstone', Microscopy and Microanalysis, vol. 17, no. 2, pp. 292-295.
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AbstractThe degradation of Sydney sandstone used to build the heritage St Mary's Cathedral in Sydney, Australia, has been investigated using environmental scanning electron microscopy combined with energy dispersive X-ray spectroscopy. This technique provided the structural details of the cementing clay and an elemental characterization the sandstone. The observed differences in the elemental composition of the unweathered and weathered sandstones were associated with changes to the clay microstructure upon weathering. The results support the substitution theory that Fe3+ replaces Al3+ in the kaolinite clay component upon weathering. An examination of the impurities present prior to a nonstructural iron removal treatment revealed the presence of minerals that may provide a source of the elements responsible for the substitution process.
Ip, KH, Stuart, BH, Thomas, PS & Ray, A 2011, 'Characterisation of poly(vinyl alcohol)-montmorillonite composites with higher clay contents', POLYMER TESTING, vol. 30, no. 7, pp. 732-736.
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Polymer composites comprised of poly(vinyl alcohol) and montmorillonite with higher clay loadings have been prepared and characterised. The extent of intercalation in the composites was examined over a range of compositions using scanning electron microscopy energy dispersive spectroscopy and x-ray diffraction. The incorporation of an acidification step followed by washing the clay results in a homogenous polymer-clay film. The source of montmorillonite was found to have an effect on the morphology of the clay in the resulting composite. Montmorillonite was obtained from two sources and different clay structures within the polymer clay composites were identified in each case, indicating that the choice of clay is an important consideration when producing poly(vinyl alcohol) montmorillonite composites with higher clay content.
Jayawardhana, M, Zhu, X & Liyanapathirana, R 2011, 'An experimental study on distributed damage detection algorithms for structural health monitoring', Journal of Physics: Conference Series, vol. 305, pp. 012068-012068.
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Jayed, MH, Masjuki, HH, Kalam, MA, Mahlia, TMI, Husnawan, M & Liaquat, AM 2011, 'Prospects of dedicated biodiesel engine vehicles in Malaysia and Indonesia', Renewable and Sustainable Energy Reviews, vol. 15, no. 1, pp. 220-235.
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Jegatheesan, V, Shu, L, Nghiem, LD, Shon, HK & Chang, C-Y 2011, 'Challenges in Environmental Science and Engineering CESE-2010 26 September-1 October 2010, The Sebel, Cairns, Queensland, Australia Total Water Management for the Sustainability of Freshwater in the Future', DESALINATION AND WATER TREATMENT, vol. 32, no. 1-3, pp. 1-3.
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Jeong, S, Nateghi, F, Nguyen, TV, Vigneswaran, S & Tu, TA 2011, 'Pretreatment for seawater desalination by flocculation: Performance of modified poly ferric silicate (PFSi-delta) and ferric chloride as flocculants', DESALINATION, vol. 283, pp. 106-110.
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Submerged microfiltration system coupled with in-line flocculation as pretreatment for seawater reverse osmosis has the potential to remove organic compounds and mitigate fouling. The effect of flocculation on the performance of microfiltration (MF) was investigated using two flocculants, namely, modified poly ferric silicate (PFSi-δ) and ferric chloride (FeCl3). The experimental results were analysed in terms of organic removal efficiency and critical flux. Both PFSi-δ and FeCl3 were found to be suitable as pretreatment because of their capacity in removing organic compounds. The results show that PFSi-δ was better than FeCl3 in terms of removing turbidity and dissolved organic carbon (DOC), particularly in removing hydrophilic compounds. The highest DOC removals of 68% and 57% were obtained when PFSi-δ at a dose of 1.2 mg Fe3+/L and FeCl3 at 3 mg Fe3+/L were used, respectively. It was observed that PFSi-δ (1.2 mg Fe3+/L) and FeCl3 (3 mg Fe3+/L) led to an increase of critical flux from 20 L/m2 h to 35 L/m2 h and 55 L/m2 h, respectively. © 2011 Elsevier B.V. All rights reserved.
Jeong, S, Nguyen, TV & Vigneswaran, S 2011, 'Submerged membrane coagulation hybrid system as pretreatment to organic matter removal from seawater', Water Supply, vol. 11, no. 3, pp. 352-357.
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In this study, a commonly used ferric chloride was utilised as coagulant for removing organic compounds from seawater. More than 57% of dissolved organic carbon (DOC) was removed at optimum dosage of 3 mg Fe+3/L. The coagulation by FeCl3 at optimum dosage could remove a majority (95%) of hydrophobic compounds. The results from Liquid Chromatography – Organic Carbon Detector showed that only <0.02 mg/L of hydrophobic compounds was found after coagulation. In addition, the modified fouling index decreased considerably from 15,848 s/L2 with raw seawater to 3,025 s/L2 with seawater after coagulation. In-line coagulation coupled with submerged membrane system (ICSMS) was also trialled. It is observed that critical flux was increased from 20 L/m2·h in the conventional submerged membrane system to 55 L/m2 h in ICSMS. The ICSMS could remain the high DOC removal efficiency (more than 70%) at filtration rate of 20 L/m2 h when keeping the development of trans-membrane pressure was significant lower than that of conventional submerged membrane system.
Johir, MAH, Aryal, R, Vigneswaran, S, Kandasamy, J & Grasmick, A 2011, 'Influence of supporting media in suspension on membrane fouling reduction in submerged membrane bioreactor (SMBR)', Journal of Membrane Science, vol. 374, no. 1-2, pp. 121-128.
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In this study, the SMBR was compared in terms of membrane fouling with and without the addition of suspended medium in the membrane reactor. The effectiveness of medium in suspension in submerged membrane bioreactor (SMBR) was evaluated at different filtration flux. The SMBR was operated at a flux of 5-30L/m2h (corresponding hydraulic retention time of 10-1.7h) with and without suspended medium. The suspended medium used in this study was granular activated carbon (GAC; particle size 300-600mm) at air scouring (aeration) rates of 0.5-1.5m3m-2 membrane areah-1. At higher aeration rate of 1.5m3/m2 membrane areah, the effect of flux on membrane resistance was found to be negligible. The reduction of aeration rate from 1.5 to 1.0m3m-2 membrane areah-1 resulted in a sudden rise of TMP. The addition of suspended medium prevented a sudden rise of TMP (total membrane resistance reduced from 51×1011 to 20×1011m-1). The organic removal efficiency remained high irrespective of flux. The molecular weight distribution (MWD) and excitation emission matrix (EEM) analysis of SMBR effluent showed a range of organic (composed of amino acids, biopolymers, humics and fulvic acids type substances) removed by the GAC both by scouring and adsorption mechanisms. © 2011 Elsevier B.V.
Johir, MAH, George, J, Vigneswaran, S, Kandasamy, J & Grasmick, A 2011, 'Removal and recovery of nutrients by ion exchange from high rate membrane bio-reactor (MBR) effluent', Desalination, vol. 275, no. 1-3, pp. 197-202.
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In this study a membrane bioreactor (MBR) with ion-exchange as post-treatment was investigated for organic removal and nutrient recovery. The MBR was operated at a short HRT of 4h in order to mainly remove organic carbon. This was followed by an ion-exchange process to remove and later recover the nitrogen and phosphorus from the MBR effluent. The increase in membrane resistance was reduced by 90% (from 0.061 to 0.006m-1d-1) when the air scouring rate was increased from 0.5 to 1.5m3/m2membrane areah. The organic removal rate in terms of DOC was 85-90%. The bio-polymer in the molecular weight range of 24,500Da was retained by the membrane of the MBR while humic type substances and lower molecular organic matter (molecular weight of 360-60Da) were not effectively removed by the membrane. The ion-exchange process effectively removed the nutrients from the effluent of the MBR. The retention of PO43- and NO3- by the two ion-exchange columns in series was 85% and 95% respectively. Over 95-98% phosphate and nitrate recovery was obtained during regeneration of columns with 1% NaCl of 20 bed volumes. This integrated process can remove pollutants and at the same time recover nutrients and thus open a new source for nitrogen and phosphorous. © 2011 Elsevier B.V.
Kalam, MA & Masjuki, HH 2011, 'An experimental investigation of high performance natural gas engine with direct injection', Energy, vol. 36, no. 5, pp. 3563-3571.
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Kalam, MA, Masjuki, HH, Jayed, MH & Liaquat, AM 2011, 'Emission and performance characteristics of an indirect ignition diesel engine fuelled with waste cooking oil', Energy, vol. 36, no. 1, pp. 397-402.
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Kalam, MA, Masjuki, HH, Varman, M & Liaquat, AM 2011, 'Friction and wear characteristics of waste vegetable oil contaminated lubricants', International Journal of Mechanical and Materials Engineering, vol. 6, no. 3, pp. 431-436.
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In this paper, a four-ball tribotester was used with standard test method IP-239 to evaluate friction and wear characteristics of normal lubricant, additive added lubricant and waste vegetable oil (WVO) contaminated lubricants. The balls used in four-ball tribotester were based on carbon-chromium steel ball bearings. The results obtained to present friction and wear characteristics are coefficient of friction (μ), wear scar diameter (WSD), flash temperature parameter (FTP), viscosity index (VI) and total acid number (TAN). Each test was conducted for five different loads from 50 kg to 90 kg with an interval of 10 kg. The lubricant was contaminated with WVO from 1% to 5%. The normal lubricant (as sample A) was used for comparison purposes. The test results showed that WVO contaminated lubricants with suitable anti-wear additive can reduce wear and friction coefficient. The objective of this investigation is to develop a new lubricant based on waste palm oil (such as WVO).
Khan, I, François, R & Castel, A 2011, 'Mechanical Behavior of Long-Term Corroded Reinforced Concrete Beam', MODELLING OF CORRODING CONCRETE STRUCTURES, vol. 5, pp. 243-258.
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Khorshed, C, Vigneswaran, S, Kandasamy, J, Aryal, R & Dharmapalan, D 2011, 'Assessment of water treatment processes: detailed organic matter characterisation and membrane fouling indices at the Loddon Water Treatment Plant, Victoria, Australia', Water Supply, vol. 11, no. 3, pp. 274-280.
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Recent advances in membrane technology have led to its broad application, and reverse osmosis (RO) systems now represent the fastest growing segment of the desalination market. Its performance is hindered by membrane fouling. In this study pre-treatment methods to reduce RO fouling were investigated including flocculation, adsorption and ion exchange. Detailed organic characterisations were made in terms of florescence spectroscopy excitation emission matrix (EEM), UV254 absorbance and liquid chromatography-organic carbon detection (LCOCD). The different pre-treatment methods were assessed in terms of the fouling potential. This was quantified in terms of the modified fouling index measured using a dead-end cell micro-filtration (MF) unit. The existing pre-treatment of granular activated carbon (GAC) filter led to a good organic removal. Among the pre-treatment methods tested in the laboratory, purolite ion exchange/adsorption was found to be better than FeCl3 flocculation in terms of the amount as well as the wide range of organics removal. A pre-treatment of flocculation with Poly-ferric-silicate (PFSi) as flocculent gave a higher removal of organic matter compared to other pre-treatments tested. DOC was reduced from 11.5 to 4.25 mg/L, and it removed mostly the humic type substances.
Kreit, A, Al-Mahmoud, F, Castel, A & François, R 2011, 'Repairing corroded RC beam with near-surface mounted CFRP rods', Materials and Structures, vol. 44, no. 7, pp. 1205-1217.
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Kus, B, Kandasamy, J, Vigneswaran, S, Shon, HK & Areerachakul, N 2011, 'Water quality of membrane filtered rainwater', DESALINATION AND WATER TREATMENT, vol. 32, no. 1-3, pp. 208-213.
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Although most Australians receive their domestic supply from reticulated mains or town water, there are vast areas with very low population densities and few reticulated supplies. In many of these areas rainwater collected in tanks is the primary source of drinking water. Heavy metals are a concern as their concentration in rainwater tanks was found to exceed recommended levels suitable for human consumption. This paper reports on experimental investigations where rainwater collected from a typical domestic roof in Sydney, Australia was treated in two stages of filtration including granular activated carbon (GAC) as a pre-treatment adsorption filter media and a metallic membrane from Steri-flow Filtration Systems Pty. Ltd. The quality of the treated rainwater was compared against the drinking water standards to determine its suitability as a supplement for potable water supply. The pollutants analysed were heavy metals, total coliform and faecal coliforms, total organic carbon, total suspended solids and turbidity. The results indicate that before treatment, the rainwater already complied with many of the parameters specified in drinking water standards. The metallic membrane performed well in removing suspended particles and heavy metals from the rainwater. The performance of the metallic membrane is greatly improved by the use of pre-treatment such as GAC which was used in this experiment.
Kus, BG, Kandasamy, JK, Vigneswaran, S & Shon, H 2011, 'Water Quality in Rainwater Tanks in Rural and Metropolitan Areas of New South Wales, Australia', Journal of Water Sustainability, vol. 1, no. 1, pp. 33-43.
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This paper compares the water quality of rainwater tanks throughout the Sydney metropolitan area to that in rural New South Wales, Australia. The water quality is compared against the Australian Guidelines for Water Recycling (AGWR) to determine if the untreated rainwater from both areas can be considered suitable for non-potable water supply without filtration. Additionally this paper reports on a set of experiments where rainwater collected from a typical domestic roof in Sydney, New South Wales, Australia was treated by a pre-treatment of granular activated carbon (GAC) adsorption filter followed by micro-filtration. The GAC column removed the pollutants through an adsorption mechanism. GAC is a macroporous solid with a very large surface area providing many sites for adsorption and it is this property that makes it an efficient adsorbent. The parameters analysed were ammonia, anions and cations, heavy metals, nitrate and nitrite, pH, total hardness, total organic carbon, total suspended solids and turbidity. The results indicate that before treatment, the rainwater already complied to many of the parameters specified in the AGWR, certain pollutants have the potential at times to exceed the AGWR. The water quality was within the AGWR limits after the treatment. The micro- filtration flux values demonstrate that rainwater was able to be filtered through the membranes under low gravitational heads that are typically available in a rainwater tank while still producing sufficient membrane flux and pollutant removal rates.
Lee, JH, Zhou, JL & Kim, SD 2011, 'Effects of biodegradation and sorption by humic acid on the estrogenicity of 17β-estradiol', Chemosphere, vol. 85, no. 8, pp. 1383-1389.
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The removal of 17β-estradiol (E2) by biodegradation and sorption onto humic acid (HA) was examined at various HA concentrations. Subsequently, estrogenicity associated with E2 removal was estimated using E-screen bioassay. Results showed that E2 biodegradation and its subsequent transformation to estrone (E1) were significantly reduced with increasing HA concentration. In addition, the presence of nutrients enhanced the biodegradation of E2. Overall, E2 biodegradation was the dominating contributor to its removal, which demonstrated a significantly negative correlation with E2 sorption at various HA concentrations. The sorption of E2 by HA was significantly enhanced with increasing HA concentration. Estrogenicity associated with residual E2 showed that there existed a significant difference among various HA concentrations, with the lowest value in the absence of HA. The findings suggest that the presence of HA and nutrients in natural waters should be considered in assessing estrogenicity of environmental samples due to complex sorption and biodegradation processes. © 2011 Elsevier Ltd.
Leung, A, Wiltshire, J, Blencowe, A, Fu, Q, Solomon, DH & Qiao, GG 2011, 'The effect of acrylamide-co-vinylpyrrolidinone copolymer on the depression of talc in mixed nickel mineral flotation', Minerals Engineering, vol. 24, no. 5, pp. 449-454.
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Li, J & Hao, H 2011, 'A Two-Step Numerical Method for Efficient Analysis of Structural Response to Blast Load', International Journal of Protective Structures, vol. 2, no. 1, pp. 103-126.
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Even with modern computer power, detailed numerical modeling and simulation of structure response to blast loads are still extremely expensive and sometimes prohibitive because it is very time consuming and requires huge computer memory. Often compromise has to be made between simulation efficiency and simulation accuracy. A lot of research efforts have been spent on improving the computational efficiency. Most of these researches concentrate on simplifying the structures, such as simplifying a structure to an equivalent SDOF system, use smeared reinforcement steel and concrete model, use substructure approach to only model part of the structure in detail. Although these approaches under certain conditions yield reliable predictions, each of them has its associated limitations. Recently a two-step method was developed to improve the computation and modeling efficiency of structure response to blast loads. Instead of simplifying the structure, the proposed method calculates the structural responses in two steps. The first step calculates the structural responses in the loading phase and the second calculates the free vibration responses with the velocity profile of the structure at the end of the loading phase as initial conditions. Using a reinforced concrete beam as the example, it was found that the proposed method yields reliable predictions of the overall beam deflection and stress in longitudinal reinforcement bars with less than 10% computational time as compared to a detailed FE model simulation. However, the predicted stress in hoop reinforcements near the beam supports is not as good. In this paper, the method is improved by also including displacement response at the end of the forced-vibration phase as the initial conditions in the free vibration analysis. The same reinforced concrete beam is used. The results show that including the displacement initial conditions in the two-step method leads to an improved prediction of the beam re...
Li, J & Hao, H 2011, 'Development of a Simplified Numerical Method for Structural Response Analysis to Blast Load', Procedia Engineering, vol. 14, pp. 2558-2566.
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The response of structural concrete elements under extremely short duration dynamic loads is of great concern nowadays. The most prevailing method to this problem is based on SDOF simplification. It is well known that the SDOF model can reliably predict the overall structural component response if the response follows predominantly a predefined damage mode such as shear or flexural mode. However, it cannot reliably predict localized failure of structures. Moreover, reliable deflection shape and damage criterion, which are critical for developing the equivalent SDOF model, are difficult to define. Therefore, although most design and analysis are still based on SDOF approach, more and more analyses are conducted with detailed Finite Element (FE) modelling. However, due to the short time duration as well as the huge loading magnitude, it is extremely difficult and time consuming to perform FE structural response analysis to blast loads, even with modern computer power. In this paper, a numerical approach, which substantially reduces the modelling and computational effort in analysing structural responses to blast load, is presented. Based on the short duration of blast load, the structural response is divided into two parts: forced vibration phase and free vibration phase. In the proposed method, the response during the forced vibration phase is approximately solved using the SDOF approach. Using the estimated response quantities at the end of the forced vibration phase as the initial conditions, a detail FE model in LS-DYNA is established and free vibration response is solved. This approach, while yielding reasonably accurate response calculations, substantially reduces the modelling and computational effort. To demonstrate the method, a reinforced concrete beam is analysed using both the conventional detailed FE modelling and the proposed approach. Comparisons of the numerical results from the two methods demonstrate the reliability of the proposed metho...
Li, J, Dackermann, U, Xu, Y-L & Samali, B 2011, 'Damage identification in civil engineering structures utilizing PCA-compressed residual frequency response functions and neural network ensembles', STRUCTURAL CONTROL & HEALTH MONITORING, vol. 18, no. 2, pp. 207-226.
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This paper presents a non-destructive, global, vibration-based damage identification method that utilizes damage pattern changes in frequency response functions (FRFs) and artificial neural networks (ANNs) to identify defects. To extract damage features and to obtain suitable input parameters for ANNs, principal component analysis (PCA) techniques are applied. Residual FRFs, which are the differences in the FRF data from the intact and the damaged structure, are compressed to a few principal components and fed to ANNs to estimate the locations and severities of structural damage. A hierarchy of neural network ensembles is created to take advantage of individual information from sensor signals. To simulate fieldtesting conditions, white Gaussian noise is added to the numerical data and a noise sensitivity study is conducted to investigate the robustness of the developed damage detection technique to noise. Both numerical and experimental results of simply supported steel beam structures have been used to demonstrate effectiveness and reliability of the proposed method.
Li, X, Hai, FI & Nghiem, LD 2011, 'Simultaneous activated carbon adsorption within a membrane bioreactor for an enhanced micropollutant removal', Bioresource Technology, vol. 102, no. 9, pp. 5319-5324.
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Li, X, Hai, FI, Tadkaew, N, Gilbertson, S & Nghiem, LD 2011, 'Strategies to enhance the removal of the persistent pharmaceutically active compound carbamazepine by membrane bioreactors', Desalination and Water Treatment, vol. 34, no. 1-3, pp. 402-407.
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Li, Y & Stewart, MG 2011, 'Cyclone Damage Risks Caused by Enhanced Greenhouse Conditions and Economic Viability of Strengthened Residential Construction', Natural Hazards Review, vol. 12, no. 1, pp. 9-18.
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Hurricanes and tropical cyclones constitute significant sources of economic loss and social disruption. Furthermore, according to the Intergovernmental Panel on Climate Change, enhanced greenhouse conditions may increase the intensity and/or frequency of tropical cyclones (hurricanes), which potentially will result in more wind damage. The paper develops a risk-cost-benefit framework to assess regional cyclone damage risks and economic viability of several hazard mitigation strategies to address the challenge of potential increase in wind damage due to enhanced greenhouse conditions, using residential construction in North Queensland, Australia as an example. The analysis includes a probabilistic wind model to account for cyclone intensity and frequency, and a vulnerability function to represent the potential damage for a given wind speed. Increases in mean annual maximum wind speed from 0 to 25% over 50 years are considered to represent the uncertainty in changing wind hazard patterns as a result of climate change. The effect of regional changes to building inventory, rate of retrofitting, cost of retrofit, reduction in vulnerability, and discount rate will be considered. The risk-based cost-benefit analysis can be used to help optimize the timing and extent of retrofitting existing houses to adapt to the potential impact of enhanced greenhouse conditions. © 2011 ASCE.
Lin, ZW, Li, YJ, Zhu, JG, Wang, XL, Dou, SX, Guo, YG, Lei, G, Wang, Y, Philips, M, Cortie, M, Li, YC, Choi, K-Y & Shi, X 2011, 'Visualization of vortex motion in FeAs-based BaFe1.9Ni0.1As2 single crystal by means of magneto-optical imaging', JOURNAL OF APPLIED PHYSICS, vol. 109, no. 7, pp. 0-0.
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Superconductivity has been found in newly discovered iron-based compounds. This paper studies the motion of magnetic vortices in BaFe1.9Ni 0.1As2 single crystal by means of the magneto-optical imaging technique. A series of magneto-optical images reflecting magnetic flux distribution at the crystal surface were taken when the crystal was zero-field cooled to 10 K. The behavior of the vortices, including penetration into and expulsion from the single crystal with increasing and decreasing external fields, respectively, is discussed. The motion behavior is similar to that observed in high-Tc superconducting cuprates with strong vortex pinning; however, the flux-front is irregular due to randomly distributed defects in the crystal. © 2011 American Institute of Physics.
Listowski, A, Ngo, H, Guo, W, Vigneswaran, S, Shin, H & Moon, H 2011, 'Greenhouse Gas (GHG) Emissions from Urban Wastewater System: Future Assessment Framework and Methodology', Journal of Water Sustainability, vol. 1, no. 1, pp. 113-125.
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Over the last two decades much scientific effort has been expended on the radiative gaseous emissions in the atmosphere. Although there are no regulatory requirements for managing gaseous emissions at present, the long term indications are, that impact relater to air pollution must embrace the broad diversity and challenges associated with urban wastewater cycle management. This study has been considered as a precursor to development of a comprehensive impact assessment of gaseous emission from urban wastewater infrastructure and treatment facilities. It has been carried out in consideration of the future climate change scientific projections, including socio-economic and environmental impacts. Major progress could be gained from systemic approaches in relation to factors influencing emission and the collected data demonstrates correlation between wastewater quality, treatment and energy used with the level of emission. An early attempt was made to attribute environmental impact and costs on per capita basis, as the weight of responsibility to take action is shifting to the community and individuals. The presented framework and methodology offers reliable evaluation of gaseous emissions is an integrated context comprising technology, environment, social and economic factors.
Listowski, A, Ngo, HH, Guo, WS & Vigneswaran, S 2011, 'A novel integrated assessment methodology of urban water reuse', WATER SCIENCE AND TECHNOLOGY, vol. 64, no. 8, pp. 1642-1651.
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Wastewater is no longer considered a waste product and water reuse needs to play a stronger part in securing urban water supply. Although treatment technologies for water reclamation have significantly improved the question that deserves further analysis is, how selection of a particular wastewater treatment technology relates to performance and sustainabiiity? The proposed assessment model integrates; (i) technology, characterised by selected quantity and quality performance parameters; (ii) productivity, efficiency and reliability criteria; (iii) quantitative performance indicators; (iv) development of evaluation model. The challenges related to hierarchy and selections of performance indicators have been resolved through the case study analysis. The goal of this study is to validate a new assessment methodology in relation to performance of the microfiltration (MF) technology, a key element of the treatment process. Specific performance data and measurements were obtained at specific Control and Data Acquisition Points (CP) to satisfy the input-output inventory in relation to water resources, products, materiai flows, energy requirements, chemicals use, etc. Performance assessment process contains analysis and necessary linking across important parametric functions leading to reliable outcomes and results.
Liu, K, Law, SS & Zhu, XQ 2011, 'A Bonding Damage Detection Method with Force-Based Beam Element', Procedia Engineering, vol. 14, pp. 1174-1182.
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Liu, MD & Indraratna, BN 2011, 'General Strength Criterion for Geomaterials Including Anisotropic Effect', International Journal of Geomechanics, vol. 11, no. 3, pp. 251-262.
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Liu, S-G, Ni, B-J, Li, W-W, Sheng, G-P, Tang, Y & Yu, H-Q 2011, 'Modeling of the Contact–Adsorption–Regeneration (CAR) activated sludge process', Bioresource Technology, vol. 102, no. 3, pp. 2199-2205.
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Liu, W, Wang, J, Wang, J, Ding, W & Almagbile, A 2011, 'Measurable Realistic Image-based 3D Mapping', Archives of Photogrammetry, Cartography and Remote Sensing, vol. 22, pp. 297-310.
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This paper proposes and demonstrates a 3D map concept that is realistic and image-based, that enables geometric measurements and geo-location services. Additionally, image-based 3D maps provide more detailed information of the real world than 3D model-based maps. The image-based 3D maps use geo-referenced stereo images or panoramic images. The geometric relationships between objects in the images can be resolved from the geometric model of stereo images. The panoramic function makes 3D maps more interactive with users but also creates an interesting immersive circumstance. Actually, unmeasurable image-based 3D maps already exist, such as Google street view, but only provide virtual experiences in terms of photos. The topographic and terrain attributes, such as shapes and heights though are omitted. This paper also discusses the potential for using a low cost land Mobile Mapping System (MMS) to implement realistic image 3D mapping, and evaluates the positioning accuracy that a measureable realistic image-based (MRI) system can produce. The major contribution here is the implementation of measurable images on 3D maps to obtain various measurements from real scenes.
Loth, L, Osmani, MG, Kalam, MA, Chakraborty, RK, Wadsworth, J, Knowles, NJ, Hammond, JM & Benigno, C 2011, 'Molecular Characterization of Foot-and-Mouth Disease Virus: Implications for Disease Control in Bangladesh', Transboundary and Emerging Diseases, vol. 58, no. 3, pp. 240-246.
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Luo, L, Wang, XC, Guo, W & Ngo, H 2011, 'Novel conceptual models for thermodynamic analysis of urban water systems', Journal of Water Sustainability, vol. 1, no. 2, pp. 13-23.
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Urban water system (UWS) can be thermodynamically analysed by calculating the entropy budget based on the increase of entropy due to internal and/or external contributions. From different internal and external parts, two novel conceptual models of thermodynamic analysis for an UWS were proposed. For conceptual model 1, natural UWS as a pseudo-reversible process is internal contribution, while the external part of the UWS is artificial water cycle. When the entropy change of the natural UWS is equal to zero, the entropy change of the UWS is considered as the entropy change by the artificial water cycle. The calculations of entropy change for artificial water cycle are based on water balance and purification reactions of selected kinds of typical pollutants in the UWS. For conceptual model 2, the internal entropy change of the UWS is water body, and it is assumed to be zero due to dynamically equilibrium of the water body. The calculation of external entropy change caused by the natural water cycle was proposed to be dependent on meteorological and hydrological data whilst the external entropy change caused by the artificial water cycle could be obtained from mass balance and treatment process analysis.
Mahlia, TMI & Chan, PL 2011, 'Life cycle cost analysis of fuel cell based cogeneration system for residential application in Malaysia', Renewable and Sustainable Energy Reviews, vol. 15, no. 1, pp. 416-426.
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Mahlia, TMI, Razak, HA & Nursahida, MA 2011, 'Life cycle cost analysis and payback period of lighting retrofit at the University of Malaya', Renewable and Sustainable Energy Reviews, vol. 15, no. 2, pp. 1125-1132.
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Mahlia, TMI, Taufiq, BN, Ong, KP & Saidur, R 2011, 'Exergy analysis for day lighting, electric lighting and space cooling systems for a room space in a tropical climate', Energy and Buildings, vol. 43, no. 7, pp. 1676-1684.
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Mainali, B, Ngo, HH, Guo, W, Pham, TTN & Johnston, A 2011, 'Feasibility assessment of recycled water use for washing machines in Australia through SWOT analysis', RESOURCES CONSERVATION AND RECYCLING, vol. 56, no. 1, pp. 87-91.
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Sustainable urban water consumption has become a critical issue in Australia due to increasing urbanization, the countryâs dry climate and its increasingly variable rainfall. Water recycling is considered vital to alleviate the demand on limited water supplies. The demands on water utilities to develop water recycling capacity and supplies are therefore expected to intensify in Australia. Dual reticulation systems have already been introduced in many cities in Australia and this is likely to expand to many other cities in the future. Developed and proposed dual reticulation schemes in Australia demand the substantial replacement of tap water with recycled water to ensure system optimisation and the sustainability of water supplies. This study successfully applies Strengths, Weaknesses, Opportunities, and Threats (SWOT) analysis as a research tool to assess the feasibility of use of recycled water in washing machine applications. Through the identification of the reuse schemes' strengths (elements to leverage and build on) and weaknesses (areas to seek assistance and support) in addition to community opportunities (areas to leverage for program advantages) and threats (elements that could hinder the scheme), the positive aspects for the use of recycled water in washing machines is observed. Further study to address the specific concerns of the general public and the development of guidelines for this new end use is however essential to guide the implementation of recycled water schemes.
Mainali, B, Ngo, HH, Guo, WS, Pham, TTN, Wang, XC & Johnston, A 2011, 'SWOT analysis to assist identification of the critical factors for the successful implementation of water reuse schemes', DESALINATION AND WATER TREATMENT, vol. 32, no. 1-3, pp. 297-306.
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The reuse of urban wastewater has been recognised as an important alternative source of water and is a key aspect of sustainable water policy. As it is a promising innovation, a number of direct and indirect water reuse projects have been instigated and proposed, both nationally and internationally. However there is some uncertainty regarding the effectiveness and impact of these water reuse schemes (WRS). This study investigates the applicability of Strengths, Weaknesses, Opportunities, and Threats (SWOT) as an analysis tool for formulating the critical factors in terms of the implementation of water reuse schemes. Basically, this work adopts an existing multiple case study design method and makes use of SWOT to analyse all critical factors for each selected water reuse scheme. The strengths and weaknesses of successful and unsuccessful WRS are analysed followed by an assessment of the corresponding external opportunities and threats. On this basis, the critical factors considered for the successful implementation of the WRS are identified. A qualitative investigation using SWOT analysis has therefore been successfully implemented. © 2011 Desalination Publications. All rights reserved.
Mazandarani, A, Mahlia, TMI, Chong, WT & Moghavvemi, M 2011, 'Fuel consumption and emission prediction by Iranian power plants until 2025', Renewable and Sustainable Energy Reviews, vol. 15, no. 3, pp. 1575-1592.
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Meng, F, Zhou, Z, Ni, B-J, Zheng, X, Huang, G, Jia, X, Li, S, Xiong, Y & Kraume, M 2011, 'Characterization of the size-fractionated biomacromolecules: Tracking their role and fate in a membrane bioreactor', Water Research, vol. 45, no. 15, pp. 4661-4671.
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Mohammadnejad, M, Ghazvini, M, Mahlia, TMI & Andriyana, A 2011, 'A review on energy scenario and sustainable energy in Iran', Renewable and Sustainable Energy Reviews, vol. 15, no. 9, pp. 4652-4658.
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Mohammed, T, Vigneswaran, S & Kandasamy, J 2011, 'Biofiltration as pre-treatment to water harvesting and recycling', Water Science and Technology, vol. 63, no. 10, pp. 2097-2105.
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This paper presents the results of the long term biofilter experiments conducted with raw stormwater collected from a canal at Carlton, in Sydney. Anthracite and granular activated carbon (GAC) were used as a single filter media in biofilter columns. Media heights of 75 and 40 cm were used. The filter columns were operated at filtration velocities of 0.12 and 0.25 m/h. The removal efficiency for turbidity and DOC for the GAC filter media were found to be 75% and almost 100% respectively. The removal efficiency for the anthracite filter was much lower. Molecular weight distribution analysis showed an almost similar trend to the DOC removal. Compared with anthracite filter media, the GAC biofilter removed a much larger range of organic compounds present in the stormwater. The GAC biofilter removes organic matter earlier as compared to anthracite. Based on a limited sample of stormwater, the removal efficiency for phosphorus was upto 74% and that of nitrogen was up to 30%. In general GAC filter shows higher heavy metal removal efficiency than anthracite. The removal of zinc, iron, lead and nickel were good. However the concentration of heavy metal in the raw surface water sample was low.
Moreno-de las Heras, M, Saco, PM, Willgoose, GR & Tongway, DJ 2011, 'Assessing landscape structure and pattern fragmentation in semiarid ecosystems using patch-size distributions', Ecological Applications, vol. 21, no. 7, pp. 2793-2805.
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Mullai, P, Arulselvi, S, Ngo, H-H & Sabarathinam, PL 2011, 'Experiments and ANFIS modelling for the biodegradation of penicillin-G wastewater using anaerobic hybrid reactor', BIORESOURCE TECHNOLOGY, vol. 102, no. 9, pp. 5492-5497.
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The performance of an anaerobic hybrid reactor (AHR) for treating penicillin-G wastewater was investigated at the ambient temperatures of 30-35 degrees C for 245 days in three phases. The experimental data were analysed by adopting an adaptive network-ba
Mullard, JA & Stewart, MG 2011, 'Corrosion-induced cover cracking: New test data and predictive models', ACI Structural Journal, vol. 108, no. 1, pp. 71-79.
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This paper presents an improved model that will be used to predict the timing of corrosion-induced cover cracking for reinforced concrete (RC) structures in chloride environments. An accelerated corrosion experimental program measured concrete cover cracking for RC slabs based on various concrete covers, concrete tensile strengths, and reinforcing bar diameters. A new empirical crack propagation model based on the test data was then developed. A correction factor for concrete confinement is proposed to account for bars located at edges and corners of RC structures. A rate of loading correction factor is applied to allow the cracking times for accelerated corrosion rates to be adjusted for the lower corrosion rates 'generally found in RC structures. A statistical analysis of model accuracy is used to account for variabilities between model prediction and experimental data. Copyright © 2011, American Concrete Institute. All rights reserved.
Nghiem, LD & Cath, T 2011, 'A scaling mitigation approach during direct contact membrane distillation', Separation and Purification Technology, vol. 80, no. 2, pp. 315-322.
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Nghiem, LD, Hildinger, F, Hai, FI & Cath, T 2011, 'Treatment of saline aqueous solutions using direct contact membrane distillation', Desalination and Water Treatment, vol. 32, no. 1-3, pp. 234-241.
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Nguyen, TT, Ngo, HH, Guo, W, Phuntsho, S & Li, J 2011, 'A new sponge tray bioreactor in primary treated sewage effluent treatment', BIORESOURCE TECHNOLOGY, vol. 102, no. 9, pp. 5444-5447.
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The new attached growth sponge tray bioreactor (STB) was evaluated at different operating conditions for removing organics and nutrients from primary treated sewage effluent. This STB was also assessed when using as a pre-treatment prior to micro-filtration (MF) for reducing membrane fouling. At a short hydraulic retention time (HRT) of 40min, the STB could remove up to 92% of DOC and 40-56% of T-N and T-P at an organic loading rate (OLR) of 2.4kg COD/m3 spongeday. This OLR is the best for the STB as compared to the OLRs of 0.6, 1.2 and 3.6kg COD/m3 spongeday. At 28mL/min of flow velocity (FV), STB achieved the highest efficiencies with 92% of DOC, 87.4% of T-P, and 54.8% of T-N removal. Finally, at the optimal OLR and FV, the STB could remove almost 90% of organic and nutrient, significantly reduce membrane fouling with HRT of only 120min. © 2010 Elsevier Ltd.
Nguyen, TV, Zhang, R, Vigneswaran, S, Ngo, HH, Kandasamy, J & Mathes, P 2011, 'Removal of organic matter from effluents by Magnetic Ion Exchange (MIEX (R))', DESALINATION, vol. 276, no. 1-3, pp. 96-102.
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Magnetic Ion Exchange Resin (MIEX®) is effective in removing the majority of organic carbon from biologically treated wastewater. It removed 77% of dissolved organic carbon (DOC) from synthetic wastewater when operated in batch mode using a MIEX® concentration of 10. mL/L. A pseudo second-order reaction rate model namely the Ho model was used for the kinetic study and it was found that it provided a realistic description of the adsorption kinetics of DOC. A fluidised bed MIEX® contactor effectively removed organic matter from synthetic biologically treated sewage effluent with more than 60% DOC removal even after 172 bed volumes. The regenerated MIEX® resin did not display any significant reduction in its ability to remove organic matter. © 2011 Elsevier B.V.
Ni, B, Liu, H, Nie, Y, Zeng, RJ, Du, G, Chen, J & Yu, H 2011, 'Coupling glucose fermentation and homoacetogenesis for elevated acetate production: Experimental and mathematical approaches', Biotechnology and Bioengineering, vol. 108, no. 2, pp. 345-353.
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AbstractHomoacetogenesis is an important potential hydrogen sink in acetogenesis, in which hydrogen is used to reduce carbon dioxide to acetate. So far the acetate production from homoacetogenesis, especially its kinetics, has not been given sufficient attention. In this work, enhanced production of acetate from anaerobic conversion of glucose through coupling glucose fermentation and homoacetogenesis is investigated with both experimental and mathematical approaches. Experiments are conducted to explore elevated acetate production in a coupled anaerobic system. Acetate production could be achieved by homoacetogenesis with a relative high acetate yield under mixed fermentation conditions. With the experimental observations, a kinetic model is formulated to describe such a homoacetogenic process. The maximum homoacetogenic rate (km,homo) is estimated to be 28.5 ± 1.7 kg COD kg−1 COD day−1 with an uptake affinity constant of 3.7 × 10−5 ± 3.1 × 10−6 kg COD m−3. The improved calculation of homoacetogenic kinetics by our approach could correct the underestimation of homoacetogenesis in anaerobic fermentation processes, as it often occurs in these systems supported by literature analysis. The model predictions match the experimental results in different cases well and provide insights into the dynamics of anaerobic glucose conversion and acetate production. Furthermore, acetate production via homoacetogenesis increases by about 40% through utilizing the fed‐batch coupling system, attributed to a balance between the hydrogen production in the acetogenesis phase and the hydrogen consumption in the homoacetogenesis phase. This work provides an effective way for increased anaerobic acetate production, and gives us a better understanding about the homoacetogenic kinetics in the ana...
Ni, B, Xie, W, Chen, Y, Fang, F, Liu, S, Ren, T, Sheng, G, Yu, H, Liu, G & Tian, Y 2011, 'Heterotrophs grown on the soluble microbial products (SMP) released by autotrophs are responsible for the nitrogen loss in nitrifying granular sludge', Biotechnology and Bioengineering, vol. 108, no. 12, pp. 2844-2852.
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AbstractIn this work, nitrogen loss in the nitrite oxidation step of the nitrification process in an aerobic‐granule‐based reactor was characterized with both experimental and modeling approaches. Experimental results showed that soluble microbial products (SMP) were released from the nitrite‐oxidizing granules and were utilized as a carbon source by the heterotrophs for denitrification. This was verified by the fluorescence in situ hybridization (FISH) analysis. Microelectrode tests showed that oxygen diffusion limitation did result in an anoxic micro‐zone in the granules and allowed sequential utilization of nitrate as an electron acceptor for heterotrophic denitrification with SMP as a carbon source. To further elucidate the nitrogen loss mechanisms, a mathematic model was formulated to describe the growth of nitrite oxidizers, the formation and consumption of SMP, the anoxic heterotrophic growth on SMP and nitrate, as well as the oxygen transfer and the substrate diffusion in the granules. The results clearly indicate that the heterotrophs grown on the SMP released by the autotrophs are responsible for the nitrogen loss in the nitrifying granules, and give us a better understanding of the aerobic granules for nitrogen removal. Biotechnol. Bioeng. 2011;108: 2844–2852. © 2011 Wiley Periodicals, Inc.
Ni, B, Zeng, RJ, Fang, F, Xie, W, Xu, J, Sheng, G, Sun, Y & Yu, H 2011, 'Evaluation on factors influencing the heterotrophic growth on the soluble microbial products of autotrophs', Biotechnology and Bioengineering, vol. 108, no. 4, pp. 804-812.
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AbstractIn this work, the heterotrophic growth on the microbial products of autotrophs and the effecting factors were evaluated with both experimental and modeling approaches. Fluorescence in situ hybridization (FISH) analysis illustrated that ammonia oxidizers (AOB), nitrite oxidizers (NOB), and heterotrophs accounted for about 65%, 20%, and 15% of the total bacteria, respectively. The mathematical evaluation of experimental data reported in literature indicated that heterotrophic growth in nitrifying biofilm (30–50%) and granules (30%) was significantly higher than that of nitrifying sludge (15%). It was found that low influent ammonium resulted in a lower availability of soluble microbial products (SMP) and a slower heterotrophic growth, but high ammonium (>150 mg N L−1) feeding would lead to purely AOB dominated sludge with high biomass‐associated products contained effluent, although the absolute heterotrophic growth increased. Meanwhile, the total active biomass concentration increased gradually with the increasing solids retention time, whereas the factions of active AOB, NOB, and heterotrophs varied a lot at different solids retention times. This work could be useful for better understanding of the autotrophic wastewater treatment systems. Biotechnol. Bioeng. 2011; 108:804–812. © 2010 Wiley Periodicals, Inc.
Ni, B-J, Rittmann, BE & Yu, H-Q 2011, 'Soluble microbial products and their implications in mixed culture biotechnology', Trends in Biotechnology, vol. 29, no. 9, pp. 454-463.
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Ni, B-J, Ruscalleda, M, Pellicer-Nàcher, C & Smets, BF 2011, 'Modeling Nitrous Oxide Production during Biological Nitrogen Removal via Nitrification and Denitrification: Extensions to the General ASM Models', Environmental Science & Technology, vol. 45, no. 18, pp. 7768-7776.
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Ni, B-J, Sheng, G-P & Yu, H-Q 2011, 'Model-based characterization of endogenous maintenance, cell death and predation processes of activated sludge in sequencing batch reactors', Chemical Engineering Science, vol. 66, no. 4, pp. 747-754.
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Oh, H-J & Pradhan, B 2011, 'Application of a neuro-fuzzy model to landslide-susceptibility mapping for shallow landslides in a tropical hilly area', Computers & Geosciences, vol. 37, no. 9, pp. 1264-1276.
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Ong, HC, Mahlia, TMI & Masjuki, HH 2011, 'A review on emissions and mitigation strategies for road transport in Malaysia', Renewable and Sustainable Energy Reviews, vol. 15, no. 8, pp. 3516-3522.
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Ong, HC, Mahlia, TMI & Masjuki, HH 2011, 'A review on energy scenario and sustainable energy in Malaysia', Renewable and Sustainable Energy Reviews, vol. 15, no. 1, pp. 639-647.
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Ong, HC, Mahlia, TMI, Masjuki, HH & Norhasyima, RS 2011, 'Comparison of palm oil, Jatropha curcas and Calophyllum inophyllum for biodiesel: A review', Renewable and Sustainable Energy Reviews, vol. 15, no. 8, pp. 3501-3515.
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Park, C-H, Tijing, LD, Yun, Y & Kim, CS 2011, 'A novel electrical potential sensing method for in vitro stent fracture monitoring and detection', Bio-Medical Materials and Engineering, vol. 21, no. 4, pp. 213-222.
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This article describes a preliminary investigation and prototype fabrication of a novel potential sensing method to continuously monitor vascular stent fractures. A potential measurement system consisting of Wheatstone bridge circuit and signal conditioning circuit was designed for the cardiovascular stent durability and fatigue test. Each end of a bare and polyurethane-covered Nitinol vascular stent was electrically connected to the potential measurement system and then immersed either in simulated body fluid (SBF) media or distilled water at 36.4 ± 1 °C. When the stent experienced fracture (i.e., a cut), its electrical potential decreased with an increase in electrical resistance. This method successfully measured fractures in the stent regardless of location. Furthermore, the number of cycles at the onset of stent fracture was accurately detected and continuously monitored using this technique. Thus, the present fracture detection method, which to our knowledge is the first ever report to use electrical potential measurement for stent durability test, gives a fast, real-time, accurate and efficient detection of fractures in stent during in vitro fatigue and durability test.
Pham, TTN, Ngo, HH, Guo, W, Dang, HPD, Mainali, B, Johnston, A & Listowski, A 2011, 'Responses of community to the possible use of recycled water for washing machines: A case study in Sydney, Australia', RESOURCES CONSERVATION AND RECYCLING, vol. 55, no. 5, pp. 535-540.
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Recycled water is a valuable resource that has potential to free up potable water supplies and recharge systems while improving the environment. Recycled water for washing machine could be one of the options as new end use of recycled water to alleviate the demand on existing and limited water supplies. This paper summarizes the findings of a research survey in Sydney, Australia to explore the attitudes and opinions of community towards the use of recycled water for different purposes, especially for the washing machine. The survey showed that 97% of the respondents were aware of the persisting water shortage problem while more than 60% of the respondents supported the use of recycled water for washing clothes. This paper exposes the basic concern of participants for using recycled water in washing machine. Health issue was found as the most concerns of the community. The survey also presents the further conditions to be considered for using recycled water for washing machine according to the participants' opinions. Correlation between knowledge and attitudes of respondents was also found in this survey.
Phuntsho, S, Listowski, A, Shon, HK, Le-Clech, P & Vigneswaran, S 2011, 'Membrane autopsy of a 10 year old hollow fibre membrane from Sydney Olympic Park water reclamation plant', DESALINATION, vol. 271, no. 1-3, pp. 241-247.
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Membrane autopsy was performed for a 10. year old polypropylene (PP) hollow fibre microfiltration membrane from Sydney Olympic Park water reclamation plant. The properties of the membrane were studied using scanning electron microscope (SEM) imaging, contact angle, bubble test, thermogravimetric analysis, tensile strength test and functional group. The old and fouled membrane exhibited a significant difference in surface properties and material strength in comparison to the virgin membrane. The old and fouled membrane surface is less hydrophilic and less negatively charged indicating that aged membrane is more vulnerable to fouling than virgin membrane. The fibre material of the old fouled membrane appears less flexible and brittle. Foulant analysis indicated that major components of the metallic elements were silicon and calcium. The dissolved organic matter was mainly composed of biopolymers (hydrophilic) and humic substances (hydrophobic). © 2011 Elsevier B.V.
Phuntsho, S, Shon, HK, Hong, S, Lee, S & Vigneswaran, S 2011, 'A novel low energy fertilizer driven forward osmosis desalination for direct fertigation: Evaluating the performance of fertilizer draw solutions', JOURNAL OF MEMBRANE SCIENCE, vol. 375, no. 1-2, pp. 172-181.
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Forward osmosis (FO) is a novel and emerging low energy technology for desalination. It will be particularly more attractive, if the draw solution separation and recovery are not necessary after FO process. The application of this new concept is briefly described here in this paper for the desalination of saline water for irrigation, using fertilizer as a draw agent. Instead of separating the draw solution from desalinated water, the diluted fertilizer draw solution can be directly applied for fertigation. We report the results on the commonly used chemical fertilizers as FO draw solution. Based on the currently available FO technology, about nine different commonly used fertilizers were finally screened from a comprehensive list of fertilizers and, their performances were assessed in terms of pure water flux and reverse draw solute flux. These results indicate that, most soluble fertilizers can generate osmotic potential much higher than the sea water. The draw solutions of KCl, NaNO3 and KNO3 performed best in terms of water flux while NH4H2PO4, (NH4)2HPO4, Ca(NO3)2 and (NH4)2SO4 had the lowest reverse solute flux. Initial estimation indicates that, 1kg of fertilizer can extract water ranging from 11 to 29L from sea water. © 2011 Elsevier B.V.
Phuntsho, S, Shon, HK, Vigneswaran, S & Cho, J 2011, 'Assessing membrane fouling potential of humic acid using flow field-flow fractionation', JOURNAL OF MEMBRANE SCIENCE, vol. 373, no. 1-2, pp. 64-73.
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Flow field-flow fractionation (FlFFF), although a separation technique, has many similarities with the crossflow membrane filtration system, thereby making it an ideal tool for studying membrane fouling. This study reports the assessment of the fouling potential of humic acid on ultrafiltration membrane using asymmetrical FlFFF. The fouling potential of organic matter was assessed by quantifying the reversible and irreversible adsorption of humic acid on the membrane through analysis of FlFFF fractogram. A strong correlation was observed between the reversible/irreversible adsorption data analysed and the membrane fouling potential. This assessment was further complimented by moment analysis results in order to interpret the fouling potential of humic acid. However, further researches are necessary before this approach can serve as an alternative index for measuring membrane fouling propensity. © 2011 Elsevier B.V.
Pradhan, B 2011, 'Use of GIS-based fuzzy logic relations and its cross application to produce landslide susceptibility maps in three test areas in Malaysia', Environmental Earth Sciences, vol. 63, no. 2, pp. 329-349.
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Pradhan, M, Aryal, R, Vigneswaran, S & Kandasamy, J 2011, 'Application of air flow for mitigation of particle deposition in submerged membrane microfiltration', Desalination and Water Treatment, vol. 32, no. 1-3, pp. 201-207.
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This study investigates the effect of microfiltration operating conditions on membrane fouling of colloidal particles of kaolin clay. Experiments were conducted with a flat sheet membrane submerged in a suspension prepared from kaolin clay powder of size varying from 0.1 to 4 mm (Sigma) with a mean particle size 2.10 mm. The particle size distribution of clay was unimodal and the concentration of kaolin clay was similar to the biomass concentration in a membrane bioreactor (10 g/L). The effects of scouring and permeate flux rates were studied in terms of the membrane fouling rate. A linear relationship between the transmembrane pressure (TMP) and particle deposition was established for different air flow rates and permeate flow rates. Air scouring was more effective at a low permeate flux. There was only a minor change in the mean particle size of deposited colloidal particles on the membrane at a given flux under varying air flows and at the beginning all had a similar rise in TMP. However, at the later stages as particles accumulated on the membrane surface there was a significant rise in TMP. 15 LMH flux was observed as critical flux beyond which a rise in the permeate flux showed a sharp rise in the TMP which varied with air flow rates and particle deposition. The sharp TMP rise that occurred during the initial few hours of operation indicated that air flow for fouling mitigation strategies should target this period to optimise the membrane process. The study showed that air flow and flux rates are the two major governing factors for particle deposition on the membrane surface.
Rahman, MM, Billah, MM, Rahman, ATMM, Kalam, MA & Ahsan, A 2011, 'Numerical investigation of heat transfer enhancement of nanofluids in an inclined lid-driven triangular enclosure', International Communications in Heat and Mass Transfer, vol. 38, no. 10, pp. 1360-1367.
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Regmi, G, Indraratna, B, Nghiem, LD & Banasiak, L 2011, 'Evaluating waste concrete for the treatment of acid sulphate soil groundwater from coastal floodplains', Desalination and Water Treatment, vol. 32, no. 1-3, pp. 126-132.
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Regmi, G, Indraratna, B, Nghiem, LD, Golab, A & Prasad, BG 2011, 'Treatment of Acidic Groundwater in Acid Sulfate Soil Terrain Using Recycled Concrete: Column Experiments', Journal of Environmental Engineering, vol. 137, no. 6, pp. 433-443.
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Saidur, R, Hasanuzzaman, M, Mahlia, TMI, Rahim, NA & Mohammed, HA 2011, 'Chillers energy consumption, energy savings and emission analysis in an institutional buildings', Energy, vol. 36, no. 8, pp. 5233-5238.
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Saminathan, S, Liu, H, Nguyen, TV & Vigneswaran, S 2011, 'Organic matter removal from biologically treated sewage effluent by flocculation and oxidation coupled with flocculation', Desalination and Water Treatment, vol. 32, no. 1-3, pp. 133-137.
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Flocculation alone and flocculation coupled with oxidation process were used for removing organic matter from biologically treated sewage effluent. The performances of different flocculants such as ferric sulphate, ferric nitrate, ferric chloride, and aluminium sulphate were experimentally evaluated. Among the flocculants tested, ferric chloride was selected because of its highest dissolved organic carbon (DOC) removal efficiency (67%) and the large size of the floc (mean size d(0.5) = 53.04 μm). The optimum dosage of FeCl3 was determined as 16 mg (Fe3+)/L. Different fractionation of organic matter before and after the flocculation process was analyzed. It was observed that FeCl3 could remove 90% of hydrophobic compounds and 61% of hydrophilic compounds. Oxidation process by Fenton reagent coupled with flocculation was also trialed. It is observed that DOC removal efficiency of Fenton reagent coupled with flocculation could reach 86%. The combination of flocculation and Fenton reagent increased the hydrophilic removal to 85%.
Sarker, L, Xiang, Y, Uy, B & Zhu, X 2011, 'Damage detection of circular cylindrical shells by Ritz method', Journal of Physics: Conference Series, vol. 305, pp. 012117-012117.
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Shafie, SM, Mahlia, TMI, Masjuki, HH & Andriyana, A 2011, 'Current energy usage and sustainable energy in Malaysia: A review', Renewable and Sustainable Energy Reviews, vol. 15, no. 9, pp. 4370-4377.
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Shane, DT, Rayhel, LH, Huang, Z, Zhao, J-C, Tang, X, Stavila, V & Conradi, MS 2011, 'Comprehensive NMR Study of Magnesium Borohydride', The Journal of Physical Chemistry C, vol. 115, no. 7, pp. 3172-3177.
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Shao, W, Bouzerdoum, A, Phung, SL, Su, L, Indraratna, B & Rujikiatkamjorn, C 2011, 'Automatic Classification of Ground-Penetrating-Radar Signals for Railway-Ballast Assessment', IEEE Transactions on Geoscience and Remote Sensing, vol. 49, no. 10, pp. 3961-3972.
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Sharma, G, Choi, J, Shon, HK & Phuntsho, S 2011, 'Solar-powered electrocoagulation system for water and wastewater treatment', DESALINATION AND WATER TREATMENT, vol. 32, no. 1-3, pp. 381-388.
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The objective of this study is to investigate the feasibility of solar powered electrocoagulation (SPEC) for wastewater treatment using aluminium electrodes. Optimisation of various operating parameters such as pH, voltage/current, electrodes gap, pollutant concentration etc. were first performed using direct electrical current. SPEC reactor was designed by connecting with photovoltaic panel (PV) either directly or through a set of batteries and charge control system. SPEC process system was sensitive to variation of solar radiation when connected directly with PV panels. SPEC reactor operated for five different times in a day (4 April 2010) yielded highest organics removal of 85% for UV abs and turbidity removal of 87% at midday (10:00 AM-2:00 PM) under optimum operating conditions. Use of batteries and charge controller with PV panels provided more consistent and efficient performance for the SPEC reactor. The variation in organics and turbidity removal was within the range of 10% for experiments conducted on three different times in a day (9 April 2010) with highest removals at 10:30 AM in the morning. This study indicates that, SPEC is a potential alternative for small scale decentralised water and wastewater purification system. © 2011 Desalination Publications. All rights reserved.
Sharma, G, Shon, HK, Aryal, R & Phuntsho, S 2011, 'Performance evaluation of microfiltration with electrocoagulation and chemical coagulation pretreatment', DESALINATION AND WATER TREATMENT, vol. 34, no. 1-3, pp. 141-149.
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One of the significant parameters to be considered for evaluating the process and economic viability of crosssflow microfiltration (MF) is flux stability. The MF economics are dependent on the flux decay through the membrane caused by membrane fouling. This work aims to evaluate the performance of MF by electro and chemical coagulation as pretreatments. The performance of MF was found to be sensitive to pH of feed solution, coagulant dosing and generation time. Acrylonitrile butadiene styrene (ABS) MF membrane of pore size 0.4 μm was used in this study. Without pretreatment normalised flux declined by 94% after 160 min of MF operation using model wastewater. However with pretreatments, the MF flux was significantly improved. The optimum performance for MF with both electro and chemical coagulation pretreatments occurred at isoelectric point where the highest removal of organic and turbidity was observed. With chemical coagulation under optimum conditions (30 mg/l alum dose and pH 6.5), MF did not experience any flux decline. MF performed better with chemical coagulation compared to electrocoagulation (EC). Also organic matter removal was found to be more for chemical coagulation than for EC. © 2011 Taylor & Francis Group, LLC.
Shekarchian, M, Moghavvemi, M, Mahlia, TMI & Mazandarani, A 2011, 'A review on the pattern of electricity generation and emission in Malaysia from 1976 to 2008', Renewable and Sustainable Energy Reviews, vol. 15, no. 6, pp. 2629-2642.
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Sheng, D 2011, 'Review of fundamental principles in modelling unsaturated soil behaviour', Computers and Geotechnics, vol. 38, no. 6, pp. 757-776.
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Sheng, D & Zhou, A-N 2011, 'Coupling hydraulic with mechanical models for unsaturated soils', Canadian Geotechnical Journal, vol. 48, no. 5, pp. 826-840.
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This paper presents an alternative method to couple the hydraulic component with the mechanical component in a constitutive model for unsaturated soils. Some pioneering work on hydromechanical coupling is reviewed. Generalized constitutive relations on coupled hydromechanical behaviour are introduced. These generalized constitutive relations are then incorporated into existing mechanical and hydraulic models for unsaturated soils. A new coupling mechanism is proposed based on the fact that soil-water characteristic equations are usually obtained for constant stress, not constant volume. The proposed coupling mechanism also satisfies the intrinsic relationship between the degree of saturation and the volumetric strain for undrained compression. Numerical examples are presented to show the performance of the proposed model in predicting soil behaviour along drying and loading paths. Finally, the model is validated against experimental data for different soils.
Sheng, D, Augarde, CE & Abbo, AJ 2011, 'A fast algorithm for finding the first intersection with a non-convex yield surface', Computers and Geotechnics, vol. 38, no. 4, pp. 465-471.
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Sheng, D, Zhou, A & Fredlund, DG 2011, 'Shear Strength Criteria for Unsaturated Soils', Geotechnical and Geological Engineering, vol. 29, no. 2, pp. 145-159.
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Shear strength is one of the fundamental properties of unsaturated soils. It has been found to change with matric suction. Various shear strength equations have been proposed for predicting the shear strength versus suction relationship for unsaturated soils. Some of these equations are based on regression analysis of experimental data, while some are embodied in more complex stress-strain constitutive models. In this paper, a variety of shear strength equations are examined and compared with respect to their fit of experimental data. Data for specimens prepared from initially slurry conditions as well as data for initially compacted soil specimens are analysed. The advantages and limitations associated with various proposed shear strength equations are discussed in this paper. © 2009 Springer Science+Business Media B.V.
Shon, HK, Okour, Y, El Saliby, I, Kim, JB & Kim, J-H 2011, 'Effect of Phosphorous on the Properties of Titania Produced from Ti-Salt Flocculated Sludge in Water Treatment', Journal of Nanoscience and Nanotechnology, vol. 11, no. 8, pp. 7456-7458.
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In this study, the removal of phosphorous (P) using Ti-salt flocculation of biologically treated sewage effluent (BTSE) was investigated for a year. The pH, alkalinity and concentration of P, before and after Ti-salt flocculation, were measured and compared. The sludge of Ti-salt flocculation was incinerated at 600 C to produce titania nanoparticles which found to be doped with P. Titania nanoparticles were characterised and their photocatalytic activity under UV light irradiation were also tested. Results indicated that the removal of P, which exceeded 97% in average, was not affected by the pH and the alkalinity of BTSE. The concentration of P in titania had no effect on the characteristics of titania nanoparticles in different seasons. Titania nanoparticles exhibited superior properties in terms of BET surface area and photocatalytic activity.
Shon, HK, Vigneswaran, S, Kandasamy, J, Kim, JB & Kim, JH 2011, 'Advanced characterization techniques of organic matter in aqueous solutions', Applied Chemistry for Engineering, vol. 22, no. 1, pp. 1-14.
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Water is the most precious resource to human being, but it is polluted by different organic compounds. Organic matter (OM) in aqeous solutions is one of the important parameters of concern for human and environmental impact, and thus, it is essential to better characterize specifically targeted organic matter in aggregated and individual level of concentrations. This review presents different analytical tools and protocols to investigate detailed properties and characterization. Physical, chemical and biological aspects of OM are envisaged in terms of traditional and advanced measurement methods.
Silitonga, AS, Atabani, AE, Mahlia, TMI & Sebayang, AH 2011, 'Techno-economic analysis and environmental impact of fuel economy labels for passenger cars in Indonesia', Renewable and Sustainable Energy Reviews, vol. 15, no. 9, pp. 5212-5217.
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Silitonga, AS, Atabani, AE, Mahlia, TMI, Masjuki, HH, Badruddin, IA & Mekhilef, S 2011, 'A review on prospect of Jatropha curcas for biodiesel in Indonesia', Renewable and Sustainable Energy Reviews, vol. 15, no. 8, pp. 3733-3756.
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Singh, G, Kandasamy, J, Shon, HK & Cho, J 2011, 'Measuring treatment effectiveness of urban wetland using hybrid water quality - Artificial neural network (ANN) model', DESALINATION AND WATER TREATMENT, vol. 32, no. 1-3, pp. 284-290.
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Constructed wetlands are now commonly used as tertiary treatment for urban stormwater. The wetlands have primary advantage over other forms of treatment as they remove dissolved organics and heavy metals in conjunction with other pollutants. The effectiveness of a wetland is a primary concern for validating its compliance with design objectives and regulatory requirements. The treatment in a wetland is however complex and is dependent on input pollutants, hydraulics, physicochemical balance and biota within the wetland. Several models are available for wetlands but have limitations in simulating the physico-chemical and biological processes within the wetland. The aim of this paper is to introduce a hybrid modelling approach that involves both a deterministic model and artificial neural network (ANN) for testing the effectiveness of a constructed wetland at Olympic Park, Homebush, Sydney, Australia. This novel approach allows a combination of calibrated water quality and neural based models to predict the water quality from the wetland. The models were calibrated and validated using water quality monitoring data measured for eight months in both influent and effluent streams of the wetland. The calibrated hybrid models were then tested for treatment effectiveness for range of wet, dry and median flows conditions within the catchments. A water quality index was developed and used to quantify the effectiveness of the wetland.
Stewart, MG 2011, 'Life-safety risks and optimisation of protective measures against terrorist threats to infrastructure', Structure and Infrastructure Engineering, vol. 7, no. 6, pp. 431-440.
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A decision support analysis considers fatality risks and cost-effectiveness of protective measures, expressed in terms of expected cost spent on risk reduction per life saved for terrorist threats to infrastructure. The analysis is applicable to any item of infrastructure, but in this paper, it is applied to commercial buildings in the US. Risks may be compared with risk acceptance criteria in the form of quantitative safety goals. The risk acceptability and costeffectiveness of protective measures includes cost of the protective measures, attack probability, reduction in risk due to protective measures, probability of fatality conditional on successful terrorist attack and number of exposed individuals. The risk-based approach developed herein provides a means for initial risk screening based on the broad levels of risk and its acceptability. © 2011 Taylor & Francis.
Stewart, MG & Mueller, J 2011, 'Cost-Benefit Analysis of Advanced Imaging Technology Full Body Scanners for Airline Passenger Security Screening', Journal of Homeland Security and Emergency Management, vol. 8, no. 1.
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The Transportation Security Administration (TSA) has been deploying Advanced Imaging Technologies (AITs) that are full-body scanners to inspect a passenger's body for concealed weapons, explosives, and other prohibited items. The terrorist threat that AITs are primarily dedicated to is preventing the downing of a commercial airliner by an IED (Improvised Explosive Device) smuggled on board by a passenger. The cost of this technology will reach $1.2 billion per year by 2014. The paper develops a preliminary cost-benefit analysis of AITs for passenger screening at U.S. airports. The analysis considered threat probability, risk reduction, losses, and costs of security measures in the estimation of costs and benefits. Since there is uncertainty and variability of these parameters, three alternate probability (uncertainty) models were used to characterise risk reduction and losses. Economic losses were assumed to vary from $2-$50 billion, and risk reduction from 5-10 percent. Monte-Carlo simulation methods were used to propagate these uncertainties in the calculation of benefits, and the minimum attack probability necessary for full body scanners to be cost-effective were calculated. It was found that, based on mean results, more than one attack every two years would need to originate from U.S. airports for AITs to pass a cost-benefit analysis. However, the attack probability needs to exceed 160-330 percent per year to be 90 percent certain that full body scanners are cost-effective.
Stewart, MG, Ellingwood, BR & Mueller, J 2011, 'Homeland security: a case study in risk aversion for public decision-making', International Journal of Risk Assessment and Management, vol. 15, no. 5/6, pp. 367-367.
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Governments and their regulatory agencies normally exhibit risk-neutral attitudes in their decision-making. However, for low probability-high consequence events many decision-makers tend to be risk-averse because of the catastrophic or dire nature of the hazard or event. The degree of risk averseness can be described by utility theory. This paper will infer utility functions that reflect the level of risk averseness of regulatory agencies when adopting new safety measures - such as investing $75 billion per year of the homeland security budget to avert terrorist attacks in the USA. The utility analysis considers threat probability, risk reduction caused by regulatory action, cost of regulatory action, and losses. The expected utilities using an identical risk-averse utility function for: 1 no enhanced security expenditure 2 regulatory action associated with $75 billion of enhanced homeland security expenditure are compared and made equal to each other by modifying the risk-averse utility function. This means that both policy options are equally preferable so if the decision-maker is more risk-averse than suggested by the risk-averse utility function then regulatory action is preferable. It will be shown that the level of risk averseness needed to justify current expenditures for homeland security is considerable. Copyright © 2011 Inderscience Enterprises Ltd.
Stewart, MG, Wang, X & Nguyen, MN 2011, 'Climate change impact and risks of concrete infrastructure deterioration', Engineering Structures, vol. 33, no. 4, pp. 1326-1337.
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Atmospheric CO2 is a major cause of reinforcement corrosion in bridges, buildings, wharves, and other concrete infrastructure in Australia, United States, United Kingdom and most other countries. The increase in CO2 levels associated with global warming will increase the likelihood of carbonation-induced corrosion. Moreover, temperature rises will increase corrosion rates. Clearly, the impact of climate change on existing and new infrastructure is considerable, as corrosion damage is disruptive to society and costly to repair. The paper describes a probabilistic and reliability-based approach that predicts the probability of corrosion initiation and damage (severe cracking) for concrete infrastructure subjected to carbonation and chloride-induced corrosion resulting from elevated CO2 levels and temperatures. The atmospheric CO2 concentration and local temperature and relative humidity changes with time over the next 100 years in the Australian cities of Sydney and Darwin are projected based on nine General Circulation Models (GCMs) under (i) high CO2 emission scenario, (ii) medium CO2 emission scenario, and (iii) CO2 emission reduction scenario based on policy intervention. The probabilistic analysis included the uncertainty of CO2 concentration, deterioration processes, material properties, dimensions, and predictive models. It was found that carbonation-induced damage risks can increase by over 400% over a time period to 2100 for some regions in Australia. Damage risks for chloride-induced corrosion increase by no more than 15% over the same time period due to temperature increase, but without consideration of ocean acidity change in marine exposure. Corrosion loss of reinforcement is not significant. The results were most sensitive to increases in atmospheric CO2. © 2011 Elsevier Ltd.
Su, Y, Wu, C & Griffth, MC 2011, 'Modelling of the bond–slip behavior in FRP reinforced masonry', Construction and Building Materials, vol. 25, no. 1, pp. 328-334.
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Swaminathan, K, Grassman, TJ, Yang, L-M, Gu, Q, Mills, MJ & Ringel, SA 2011, 'Optically-aligned visible/near-infrared dual-band photodetector materials and devices on GaAs using metamorphic epitaxy', Journal of Applied Physics, vol. 110, no. 6, pp. 063109-063109.
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A monolithic, epitaxially-integrated, vertically-aligned, multi-band photodetector architecture has been demonstrated via the successful growth and fabrication of metamorphic back-to-back n-i-p/p-i-n In0.61Ga0.39P/In0.14Ga0.86As visible/near-IR dual-detector devices. The back-to-back diode design enables simultaneous and independent operation of detectors in both bands with low optical cross talk (<−10 dB outside the 690–720 nm range) and complete electrical isolation between the sub-detectors. The high electronic quality of the resultant metamorphic materials was confirmed via deep level transient spectroscopy, which revealed total trap concentrations of 5 × 1012 cm−3 for the In0.14Ga0.86As and 2 × 1014 cm−3 for the In0.61Ga0.39P sub-detectors, enabling low, room temperature reverse bias (−2 V) dark current densities of 4 × 10−8 A cm−2 and 7 × 10−12 A cm−2, respectively. High responsivity and specific detectivity values, at a working bias of −2 V, were measured: 0.41 A/W and 8.6 × 1011 cm Hz1/2/W for the In0.14Ga0.86As sub-detectors (at 980 nm), and 0.30 A/W and 2.0 × 1014 cm Hz1/2/W for the In0.61Ga0.39P sub-detectors (at 680 nm). The successful integration of high-quality lattice-mismatched materials, combined with the excellent sub-detector performances, demonstrate the potential for extending such a multi-band photodetector technology to achieve simultaneous detection of a wide range of wavelength bands with tunable cut-off wavelengths.
Swaminathan, K, Yang, L-M, Grassman, TJ, Tabares, G, Guzman, A, Hierro, A, Mills, MJ & Ringel, SA 2011, 'Metamorphic In_020Ga_080As p-i-n photodetectors grown on GaAs substrates for near infrared applications', Optics Express, vol. 19, no. 8, pp. 7280-7280.
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Tadkaew, N, Hai, FI, McDonald, JA, Khan, SJ & Nghiem, LD 2011, 'Removal of trace organics by MBR treatment: The role of molecular properties', Water Research, vol. 45, no. 8, pp. 2439-2451.
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Thomas, PS, Stuart, BH, McGowan, N, Guerbois, JP, Berkahn, M & Daniel, V 2011, 'A study of ochres from an Australian aboriginal bark painting using thermal methods', JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY, vol. 104, no. 2, pp. 507-513.
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The potential of thermogravimetric analysis (TG) as a tool for the characterisation of ochre paint used in indigenous Australian bark paintings has been investigated. TG has been combined with differential scanning calorimetry (DSC) and mass spectrometry
Tijing, LD, Jung, MY, Kim, D-W & Kim, CS 2011, 'Deposition Behavior of Self-Assembled Monolayers and Bacteria on Metallic Surfaces Using an Electrochemical Quartz Crystal Nanobalance', Journal of Nanoscience and Nanotechnology, vol. 11, no. 2, pp. 1354-1358.
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This paper presents an investigation on the deposition behavior of self-assembled monolayers (SAMs) and bacteria on titanium and gold surfaces using an electrochemical quartz crystal nanobalance (EQCN). The tests included alkanethiol and alkanesilane and three bacteria, namely: E. coli, P. fluorescens and K. aerogenes. The mass change with respect to immersion time was measured by EQCN. The results showed SAM formation on both titanium and gold surfaces, but SAM formation on gold was generally higher by 26–74% as compared to that of titanium. On the other hand, bacteria also adhered well on the two metal surfaces. E. coliand P. fluorescens had high affinity on gold and titanium surfaces, respectively, while K. aerogenes was more adherent to titanium. The results showed that titanium and gold are good metals for biomaterials yet at the same time, their bioinert property provide excellent condition for bacterial adhesion. Therefore, there is a need for proper surface preparation to optimize the use of titanium and gold as biomaterials
Tijing, LD, Lee, D-H, Kim, D-W, Cho, YI & Kim, CS 2011, 'Effect of high-frequency electric fields on calcium carbonate scaling', Desalination, vol. 279, no. 1-3, pp. 47-53.
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The present study conducted an investigation on the effect of high-frequency electric fields (HFEF) in calcium carbonate (CaCO3) scale formation on heated copper tube surfaces. Artificial hard water at varying CaCO3 hardness was used. Calcium carbonate scales were formed on a heated copper tube surface, the fouling thermal resistance was calculated, and the calcium content of the deposited CaCO3 scale was measured by an inductively coupled plasma mass spectroscopy (ICP-MS), and the cooling water was analyzed during the scaling process. No-treatment and HFEF-treatment cases were conducted and compared. The calcium content of the deposited scale dropped by 4–49% in HFEF-treatment case. The lower calcium content of the deposit corresponded to thinner deposits. Water analyses showed consistently lesser percentage drop in HFEF-treatment case primarily due to less fouling deposition. The asymptotic fouling thermal resistance in HFEF-treatment case had a maximum decrease of 88% (i.e., from 4.5 × 10− 4 to 5.4 × 10− 5 m2K/W).
Tijing, LD, Yu, M-H, Kim, C-H, Amarjargal, A, Lee, YC, Lee, D-H, Kim, D-W & Kim, CS 2011, 'Mitigation of scaling in heat exchangers by physical water treatment using zinc and tourmaline', Applied Thermal Engineering, vol. 31, no. 11-12, pp. 2025-2031.
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Tu, KL, Chivas, AR & Nghiem, LD 2011, 'Effects of membrane fouling and scaling on boron rejection by nanofiltration and reverse osmosis membranes', Desalination, vol. 279, no. 1-3, pp. 269-277.
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Tu, KL, Nghiem, LD & Chivas, AR 2011, 'Coupling effects of feed solution pH and ionic strength on the rejection of boron by NF/RO membranes', Chemical Engineering Journal, vol. 168, no. 2, pp. 700-706.
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Valipour, HR & Crews, K 2011, 'Efficient finite element modelling of timber beams strengthened with bonded fibre reinforced polymers', Construction and Building Materials, vol. 25, no. 8, pp. 3291-3300.
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This paper presents development and application of a simple and efficient frame finite element (FE) able to estimate the load-carrying capacity of timber beams flexurally strengthened with externally bonded fibre reinforced polymer (FRP) strips and near-surface mounted FRP bars. The developed element is able to model collapse due to timber crushing under compression, timber fracture under tension and FRP rupture and it is developed in the framework of a flexibility-based fibre element formulation. Furthermore, a novel method based on central difference method in conjunction with composite Simpson's integration scheme along the element axis is developed to take account of shear-slip. The developed model is employed to predict the loading capacity and the applied load-mid span deflection response of timber beams strengthened with FRP and the numerically simulated responses agree well with the corresponding experimental results. The major features of this frame FE are its simplicity and efficiency compared with more complex and computationally expensive FEs which makes it a suitable tool for practical use in design-oriented parametric studies.
Walsh, KM, Choi, M, Oberg, K, Kulke, MH, Yao, JC, Wu, C, Jurkiewicz, M, Hsu, L-I, Hooshmand, SM, Hassan, M, Janson, ET, Cunningham, JL, Vosburgh, E, Sackler, RS, Lifton, RP, DeWan, AT & Hoh, J 2011, 'A pilot genome-wide association study shows genomic variants enriched in the non-tumor cells of patients with well-differentiated neuroendocrine tumors of the ileum', Endocrine Related Cancer, vol. 18, no. 1, pp. 171-180.
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Genetic studies of midgut carcinoid cancer have exclusively focused on genomic changes of the tumor cells. We investigated the role of constitutional genetic polymorphisms in predisposing individuals to ileal carcinoids. In all, 239 cases and 110 controls were collected fromthree institutions: the Uppsala University Hospital; the Dana-Farber Cancer Institute; and the MD Anderson Cancer Center, and were genotyped using microarrays assaying >300 000 single nucleotide polymorphisms. Association with rs2208059 in KIF16B approached statistical significance (Mantel-Haenszel odds ratio=2.42, P=4.16×10 -7) at a Bonferroni-corrected level (<1.62×10-7). Using two computational algorithms, four copy-number variants (CNVs) were identified in multiple cases that were absent in study controls and markedly less frequent in ∼1500 population-based controls. Of these four constitutional CNVs identified in blood-derived DNA, a 40 kb heterozygous deletion in Chr18q22.1 corresponded with a region frequently showing loss of heterozygosity (LOH) in ileal carcinoid tumor cells based on our meta-analysis of previously published cytogenetic studies (69.7% LOH, 95% confidence interval =60.0-77.9%). We analyzed the constitutional 40 kb deletion on chr18 in our study samples with a real-time quantitative PCR assay; 14/226 cases (6.19%) and 2/97 controls (2.06%) carried the CNV, although the exact boundaries of each deletion have not been determined. Given the small sample size, our findings warrant an independent cohort for a replication study. Owing to the rarity of this disease, we believe these results will provide a valuable resource for future work on this serious condition by allowing others to make efficient use of their samples in targeted studies. © 2011 Society for Endocrinology Printed in Great Britain.
Wang, XC, Luo, L, Chen, R & Ngo, HH 2011, 'Thermodynamic analysis of an urban water system with reclaimed water as supplemental water resource', DESALINATION AND WATER TREATMENT, vol. 32, no. 1-3, pp. 307-315.
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The natural water system maintains its dynamic equilibrium through a hydrological cycle that involves a series of natural processes. Such a natural water cycle has been much disturbed by human activities in the process of water use. An urban water system was thus modeled in this paper as a series of artificial water cycles overlaid upon the natural water cycle. The system was thermodynamically analyzed by calculating the entropy budget as ÎS = ÎiS + ÎeS where ÎiS and ÎeS are the entropy increases due to natural and artificial contributions, respectively. The natural water cycle free from human disturbance should possess the nature of self maintenance of water and materials balance and could be assumed as a pseudo-reversible process with ÎiS 0. ÎeS was then supposed as to be contributed by artificial disturbances on water quantity such as by water withdrawal, and on water quality such as by pollutant discharge. A series of models were developed for calculating ÎeS. As a result of scenario analysis of urban water system in Xi'an, a metropolitan in northwestern China, using these models, it was indicated that under the current condition of water supply and wastewater treatment, if 20% of the treated wastewater could be reused, ÎeS would be decreased by 15.22% from the current level, while if the percent of treated wastewater reuse could be increased to 40%, ÎeS would be decreased by 29.93%. Thermodynamic analysis thus provided a tool for quantitative evaluation of the effect of urban wastewater reclamation and reuse.
Wang, Y, Zhu, X, Hao, H & Ou, J 2011, 'Spectral Element Model Updating for Damage Identification Using Clonal Selection Algorithm', Advances in Structural Engineering, vol. 14, no. 5, pp. 837-856.
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A spectral element model updating procedure is presented to identify damage in a structure using Guided wave propagation results. Two damage spectral elements (DSE1 and DSE2) are developed to model the local (cracks in reinforcement bar) and global (debonding between reinforcement bar and concrete) damage in one-dimensional homogeneous and composite waveguide, respectively. Transfer matrix method is adopted to assemble the stiffness matrix of multiple spectral elements. In order to solve the inverse problem, clonal selection algorithm is used for the optimization calculations. Two displacement-based functions and two frequency-based functions are used as objective functions in this study. Numerical simulations of wave propagation in a bare steel bar and in a reinforcement bar without and with various assumed damage scenarios are carried out. Numerically simulated data are then used to identify local and global damage of the steel rebar and the concrete-steel interface using the proposed method. Results show that local damage is easy to be identified by using any considered objective function with the proposed method while only using the wavelet energy-based objective function gives reliable identification of global damage. The method is then extended to identify multiple damages in a structure. To further verify the proposed method, experiments of wave propagation in a rectangular steel bar before and after damage are conducted. The proposed method is used to update the structural model for damage identification. The results demonstrate the capability of the proposed method in identifying cracks in steel bars based on measured wave propagation data.
Wu, C 2011, 'Special Issue on Protection of Structures against Blast Loading', Journal of Performance of Constructed Facilities, vol. 25, no. 5, pp. 358-359.
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Wu, C & Zhou, Y 2011, 'Simplified Analysis of Foam Cladding Protected Reinforced Concrete Slabs against Blast Loadings', International Journal of Protective Structures, vol. 2, no. 3, pp. 351-365.
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Protection of infrastructure against blast loading has been receiving more attention in recent years due to occasional engineering explosion accidents, e.g., chemical plant explosion, and intentional man-made explosions, e.g., rising terrorist attacks. An effective solution to mitigate blast effects on these buildings is to protect them with sacrificial foam claddings for absorption of blast energy. However, little research has been conducted to analyze the effectiveness of metallic foam protected reinforced concrete (RC) structural members under airblast loads. This paper is to develop a numerical model to analyze the mitigation of blast effects on foam cladding protected RC members with consideration of interaction of blast load, foam layer and protected structural member. This numerical model is a simplified SDOF system where the deformability of the RC flexural member is considered in the form of the supporting spring. The stiffness of the spring K is estimated from the resistance deflection function of the RC member which is derived from combined moment curvature and moment rotation models. Material testing was conducted on aluminum foam specimens to obtain the stress stain curve which was idealised as a rigid-perfectly plastic-locking model. The resistance deflection curve of the RC slab and the idealised rigid-perfectly plastic-locking model for foam specimen were incorporated into the coupled SDOF interaction model for dynamic analysis. A field blast testing on foam protected RC slab was conducted and the accuracy of the coupled SDOF interaction model was validated by experimental data from the blast testing of the foam protected RC slab.
Wu, C, DeWan, A, Hoh, J & Wang, Z 2011, 'A Comparison of Association Methods Correcting for Population Stratification in Case–Control Studies', Annals of Human Genetics, vol. 75, no. 3, pp. 418-427.
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SummaryPopulation stratification is an important issue in case–control studies of disease‐marker association. Failure to properly account for population structure can lead to spurious association or reduced power. In this article, we compare the performance of six methods correcting for population stratification in case–control association studies. These methods include genomic control (GC), EIGENSTRAT, principal component‐based logistic regression (PCA‐L), LAPSTRUCT, ROADTRIPS, and EMMAX. We also include the uncorrected Armitage test for comparison. In the simulation studies, we consider a wide range of population structure models for unrelated samples, including admixture. Our simulation results suggest that PCA‐L and LAPSTRUCT perform well over all the scenarios studied, whereas GC, ROADTRIPS, and EMMAX fail to correct for population structure at single nucleotide polymorphisms (SNPs) that show strong differentiation across ancestral populations. The Armitage test does not adjust for confounding due to stratification thus has inflated type I error. Among all correction methods, EMMAX has the greatest power, based on the population structure settings considered for samples with unrelated individuals. The three methods, EIGENSTRAT, PCA‐L, and LAPSTRUCT, are comparable, and outperform both GC and ROADTRIPS in almost all situations.
Wu, C, Huang, L & Oehlers, DJ 2011, 'Blast Testing of Aluminum Foam–Protected Reinforced Concrete Slabs', Journal of Performance of Constructed Facilities, vol. 25, no. 5, pp. 464-474.
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Wu, C, Yu, L & Zhou, Y 2011, 'Numerical Analysis of Metallic Foam Using Microstructure Model', International Journal of Protective Structures, vol. 2, no. 4, pp. 499-513.
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It has become a critical issue that the human life and civil facility have been threatened by the increasing terroristic explosive attack. The application of cellular materials is an effective and feasible measure to mitigate blast and impact loading on buildings due to their energy absorption capacity. The Finite Element code such as LSDYNA has been used to simulate the mechanical behaviours of cellular materials. However, most of numerical models regarded the cellular materials as homogeneous materials on the macro level which may affect the accuracy of simulation, because none of them can reflect the pore structure of cellular materials, especially for the irregular metallic foam structures. Therefore, in this study, two main microstructure models (2D/3D metallic foam) were developed for numerical simulation of closed-cell metal. In the microstructure model of metallic foam, the cell walls were represented by thin shell elements and the solid wall material of the cells is modelled as bi-linear stress-strain relationship based on the material properties of the cell wall material of metallic foam. The numerical models were validated through comparing simulated results with analytical values of plateau phase stress-strain response under static condition. With the validated microstructure models, a series of parametric studies were conducted, in order to have a better understanding about the mechanical properties of closed-cell metallic foam. The emphases of this study were on the differences between static and dynamic performances of closed-cell metallic foam specimens in both 2D and 3D cases, the relationship between dynamic increase factor and nominal strain rate.
Xie, W-M, Zhang, R, Li, W-W, Ni, B-J, Fang, F, Sheng, G-P, Yu, H-Q, Song, J, Le, D-Z, Bi, X-J, Liu, C-Q & Yang, M 2011, 'Simulation and optimization of a full-scale Carrousel oxidation ditch plant for municipal wastewater treatment', Biochemical Engineering Journal, vol. 56, no. 1-2, pp. 9-16.
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Xing, W, Ngo, HH, Guo, WS, Listowski, A & Cullum, P 2011, 'Evaluation of an integrated sponge - Granular activated carbon fluidized bed bioreactor for treating primary treated sewage effluent', BIORESOURCE TECHNOLOGY, vol. 102, no. 9, pp. 5448-5453.
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An integrated fluidized bed bioreactor (iFBBR) was designed to incorporate an aerobic sponge FBBR (ASB-FBBR) into an anoxic granular activated carbon FBBR (GAC-FBBR). This iFBBR was operated with and without adding a new starch based flocculant (NSBF) to treat synthetic primary treated sewage effluent (PTSE). The NSBF contains starch based cationic flocculants and trace nutrients. The results indicate that the iFBBR with NSBF addition could remove more than 93% dissolved organic carbon (DOC), 61% total nitrogen (T-N) and 60% total phosphorus (T-P) at just a very short hydraulic retention time of 50min. The optimum frequency of adding NSBF to the iFFBR is four times per day. As a pretreatment to microfiltration, the iFFBR could increase 5L/m2h of critical flux thus reducing the membrane fouling. In addition, better microbial activity was also observed with high DO consumption (>66%) and specific oxygen uptake rate (>35mg O2/gVSSh). © 2010 Elsevier Ltd.
Xu, H, Wang, J & Zhan, X 2011, 'GNSS Satellite Autonomous Integrity Monitoring (SAIM) using inter-satellite measurements', Advances in Space Research, vol. 47, no. 7, pp. 1116-1126.
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Yancheng, LI, Jianchun, LI & SAMALI, B 2011, 'Dynamic Performance of a Novel Magnetorheological Pin Joint', Journal of System Design and Dynamics, vol. 5, no. 5, pp. 706-715.
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Magnetorheological fluid (MRF) has received significant attention lately and MRF based devices have been proposed for structural control applications in recent years. The unique characteristics of MR fluid lies in its abilities to reversibly, repeatedly and instantly change from a free flowing liquid to a semi-solid state when exposed to a magnetic field. The electric power required to drive the MR devices can be easily provided by a battery. Possessing such unique properties, MR fluid based devices, such as MR damper, have become promising candidates in the semi-active control for civil structure applications. However, most of the published research has focused on application of MR dampers instead of exploring other type of MR devices. In addition, MR based devices exhibit complex nonlinear hysteresis behaviour and thus making their modelling a challenging task.
In this paper, a novel MR fluid based device, namely MR pin joint, is proposed as a smart structural member in development of an intelligent civil structure that can suppress unwanted vibrations to ensure safety and serviceability of the structure. After design and fabrication, experiments have been conducted to characterise dynamic behaviours of the new device under different harmonic excitations with various input currents. Response time of the MR pin joint is compared when the MR pin joint is driven under different applied currents and moving speeds. Test data shows that the MR pin joint possesses a unique behaviour in the moment-angular velocity plot. A hyperbolic hysteresis model is proposed to model such unique behaviour. The investigation presented in the paper explores dynamic performance of MR pin joint. Finally, a parametric model is developed following the investigation on the correlation of coefficients in the proposed model with the loading conditions and applied currents.
Yang, B, Ying, G-G, Zhao, J-L, Zhang, L-J, Fang, Y-X & Nghiem, LD 2011, 'Oxidation of triclosan by ferrate: Reaction kinetics, products identification and toxicity evaluation', Journal of Hazardous Materials, vol. 186, no. 1, pp. 227-235.
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Yang, Y, Fu, J, Peng, H, Hou, L, Liu, M & Zhou, JL 2011, 'Occurrence and phase distribution of selected pharmaceuticals in the Yangtze Estuary and its coastal zone', Journal of Hazardous Materials, vol. 190, no. 1-3, pp. 588-596.
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The occurrence and geochemical behavior of nine pharmaceutical compounds were investigated along the Yangtze River Estuary and its coastal area, by sampling and analysis of pharmaceuticals in sediment, suspended particulate matter (SPM), colloidal and soluble phases. In addition, the impact of sewage input was examined by sampling from sewage treatment plants (STP) effluent and its upstream and downstream in the Yangtze River. Although at relatively low concentrations in SPM and sediments, several pharmaceuticals were found at elevated concentration in filtered water samples from STP-affected sites. STP is therefore an important input of pharmaceuticals in the study area. Colloidal phase was further separated from bulk water samples using cross-flow ultrafiltration (CFUF), confirming it being an effective sorbent for pharmaceuticals with high sorption capacity which are 2-4 orders of magnitude higher than SPM. Moreover, mass balance calculations showed that significant percentages of selected pharmaceutical compounds were associated with aquatic colloids, indicating colloids as a reservoir for these contaminants in the Yangtze estuarine system. © 2011 Elsevier B.V.
Yang, Y, Li, J, Wang, H, Song, X, Wang, T, He, B, Liang, X & Ngo, HH 2011, 'An Electrocatalytic Membrane Reactor with Self‐Cleaning Function for Industrial Wastewater Treatment', Angewandte Chemie International Edition, vol. 50, no. 9, pp. 2148-2150.
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Yang, Y, Li, J, Wang, H, Song, X, Wang, T, He, B, Liang, X & Ngo, HH 2011, 'An Electrocatalytic Membrane Reactor with Self‐Cleaning Function for Industrial Wastewater Treatment', Angewandte Chemie, vol. 123, no. 9, pp. 2196-2198.
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Industrial wastewater has become a global issue due to its high concentration of pollutants, especially refractory organic compounds.[1] Membrane technology has attracted considerable attention in industrial wastewater purification over the past decades owing to its high flexibility regarding water quality and low investment costs. However, inherent membrane fouling caused by concentration polarization and pore blocking leads to low plant reliability and limits wide industrial application in wastewater treatment.[2] Controlling and mitigating membrane fouling has become the most critical problem in the field of membrane technology for water and wastewater treatment.
Yisgedu, TB, Chen, X, Lingam, HK, Huang, Z, Highley, A, Maharrey, S, Behrens, R, Shore, SG & Zhao, J-C 2011, 'Synthesis, Structural Characterization, and Thermal Decomposition Study of Mg(H2O)6B10H10·4H2O', The Journal of Physical Chemistry C, vol. 115, no. 23, pp. 11793-11802.
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Zhang, R, Castel, A & François, R 2011, 'Influence of steel–concrete interface defects owing to the top-bar effect on the chloride-induced corrosion of reinforcement', Magazine of Concrete Research, vol. 63, no. 10, pp. 773-781.
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This paper deals with the influence of the steel–concrete interface condition on the reinforcement corrosion in a chloride environment. Two large-sized concrete members were cast including horizontal reinforcements at different levels in order to create voids under the upper horizontal bars caused by the well-known ‘top-bar effect'. The walls were then sawn into small-sized specimens including one rebar. These small specimens were submitted to wetting–drying cycles in salt water (natural corrosion process). The polarisation resistance technique was performed to monitor the steel corrosion during the ageing up to 55 weeks. Chloride profiles were regularly measured and specimens were broken to observe the corrosion pattern. Results show that, first, a good-quality steel–concrete interface significantly reduces the corrosion rate in comparison with the specimen with interfacial defects. Second, before concrete cracking, the corrosion pattern observed is completely different between the specimens with or without defect. Perfect interface specimens show a typical local pitting corrosion pattern owing to chloride attack. However, specimens affected by the ‘top-bar effect' show a generalised corrosion along the steel surface affected by the void (surface under the horizontal steel bars in regard to concrete casting direction). Macrocell corrosion seems to develop between the lower surface affected by the void acting as an anode and the upper surface where the bond is perfect as the cathode. The concrete cracking is delayed for specimens affected by the ‘top-bar effect' in spite of a higher corrosion rate. This delay can be attributed to the time necessary for the rust to fill the voids.
Zhao, YX, Gao, BY, Cao, BC, Yang, ZL, Yue, QV, Shon, HK & Kim, J-H 2011, 'Comparison of coagulation behavior and floc characteristics of titanium tetrachloride (TiCl4) and polyaluminum chloride (PACl) with surface water treatment', CHEMICAL ENGINEERING JOURNAL, vol. 166, no. 2, pp. 544-550.
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Coagulation behavior of Titanium tetrachloride (TiCl4) and polyaluminum chloride (PACl) was comparatively investigated in terms of the removal of turbidity and natural organic matter (NOM) with surface water. The growth, breakage and re-growth nature of flocs were also compared. The results show that the removals of chemical oxidation demand (CODMn) and dissolved organic carbon (DOC) were 51.5% and 78.4% at optimal dosage for TiCl4 and 29.8% and 41.0% for PACl, respectively. The floc breakage and re-growth indicated that TiCl4 and PACl coagulation occurred not only by charge neutralization but also by a form of sweep flocculation. Besides, flocs formed by PACl had better recoverability than the flocs formed by TiCl4. Sludge produced from TiCl4 flocculation was calcined at 600 â¦C to produce TiO2, and the photocatalytic activity in removing reactive brilliant red (K-2BP) was evaluated in comparison with commercially available TiO2 (P-25). The photocatalytic oxidation rates of K-2BP after 2 h photocatalytic reaction were 91.4% and 92.9% for as-prepared TiO2 and P-25, respectively.
Zhao, YX, Gao, BY, Rong, HY, Shon, HK, Kim, J-H, Yue, QY & Wang, Y 2011, 'The impacts of coagulant aid-polydimethyldiallylammonium chloride on coagulation performances and floc characteristics in humic acid-kaolin synthetic water treatment with titanium tetrachloride', CHEMICAL ENGINEERING JOURNAL, vol. 173, no. 2, pp. 376-384.
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Coagulation of humic acidâkaolin synthetic water was conducted with Titanium tetrachloride (TiCl4) and/or polydimethyldiallylammonium chloride (PD) to assess the effect of coagulant aid PD on coagulation behavior and floc characteristics. Coagulation behavior was investigated in terms of the reduction of turbidity and the removal of natural organic matter (NOM). The results show that the humic acid (HA) removal increased with the addition of PD depending on the doses of it and TiCl4, and the HA removal was more enhanced by PD at low TiCl4 doses than at higher ones. In addition, PD-TiCl4 (PD dosed firstly, followed by TiCl4 addition) gave better turbidity and HA removal than TiCl4-PD (TiCl4 dosed firstly, followed by PD addition) in this investigation. The growth, breakage, regrowth and fractal nature of flocs was investigated by use of Mastersizer 2000. TiCl4 plus cationic polymer PD exhibited an apparent improvement on floc size and floc grow rate, and they were both in the following order: PD-TiCl4 > TiCl4-PD > TiCl4. Compared with TiCl4, the dual-coagulants significantly improved the floc recoverability. Besides, the dual-coagulants gave more compact floc structure than TiCl4 coagulant at each coagulant dose under investigation and the values of fractal dimension (Df) were in the order of TiCl4-PD > PD-TiCl4 > TiCl4.
Zhao, YX, Gao, BY, Shon, HK, Cao, BC & Kim, J-H 2011, 'Coagulation characteristics of titanium (Ti) salt coagulant compared with aluminum (Al) and iron (Fe) salts', JOURNAL OF HAZARDOUS MATERIALS, vol. 185, no. 2-3, pp. 1536-1542.
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In this study, the performance of titanium tetrachloride (TiCl4) coagulation and flocculation is compared with commonly used coagulants such as aluminum sulfate (Al2(SO4)3), polyaluminum chloride (PACl), iron chloride (FeCl3), and polyferric sulfate (PFS) in terms of water quality parameters and floc properties. TiCl4 flocculation achieved higher removal of UV254 (98%), dissolved organic carbon (DOC) (84%) and turbidity (93%) than other conventional coagulants. Charge neutralization and physical entrapment of colloids within coagulant precipitates and adsorption, seemed to play a significant role during TiCl4 flocculation, while the main mechanism for conventional coagulants was bridge-aggregation and adsorption. The aggregated flocs after TiCl4 flocculation showed the fastest growth rate compared to the other coagulants, with the largest floc size (801m) occurring within 8 min. The floc strength factor of PACl, Al2(SO4)3, PFS, FeCl3 and TiCl4 was 34, 30, 29, 26 and 29, respectively, while the floc recovery factor of the TiCl4 coagulant was the lowest. Based on the results of the above study, it is concluded that the TiCl4 flocculation can reduce the hydraulic retention time of slow and rapid mixing, however, careful handling of sludge is required due to the low recoverability of the aggregated floc.
Zhao, YX, Gao, BY, Shon, HK, Kim, J-H & Yue, QY 2011, 'Effect of shear force, solution pH and breakage period on characteristics of flocs formed by Titanium tetrachloride (TiCl4) and Polyaluminum chloride (PACl) with surface water treatment', JOURNAL OF HAZARDOUS MATERIALS, vol. 187, no. 1-3, pp. 495-501.
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The growth, breakage and regrowth nature of flocs formed by Titanium tetrachloride (TiCl4) and polyaluminum chloride (PACl) was comparatively evaluated with surface water treatment. A series of jar experiments were conducted to investigate the impacts of different operating parameters such as shear force, solution pH and a breakage period on floc strength and re-aggregation potential. Results indicated that the responses of flocs to different operating parameters depend on the coagulant used. The ability of floc to resist breakage decreased with the increase of shear force and breakage period. Floc strength properties were also measured in response to increasing shear force, with the results suggesting that the order of floc strength was TiCl4 > PACl. Floc regrowth of the two coagulants after exposure to high shear was limited, and flocs formed by TiCl4 displayed weaker recoverability. The flocs generated in acid conditions were more recoverable than those generated in alkaline conditions no matter which coagulant was used.
Zhao, YX, Gao, BY, Shon, HK, Kim, J-H, Yue, QY & Wang, Y 2011, 'Floc characteristics of titanium tetrachloride (TiCl4) compared with aluminum and iron salts in humic acid-kaolin synthetic water treatment', SEPARATION AND PURIFICATION TECHNOLOGY, vol. 81, no. 3, pp. 332-338.
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The floc strength and regrowth properties of TiCl4, FeCl3, and Al2 SO4)3 were comparatively evaluated using humic acidâkaolin synthetic water sample. At the given optimum dosage (20 mg/L as Ti, 8 mg/L as Fe, and 2 mg/L as Al, respectively), the floc growth, breakage and regrowth of TiCl4, FeCl3, and Al2(SO4)3 were investigated by use of a laser diffraction particle sizing device. Jar tests were conducted to investigate the impact of shear force and breakage period on floc breakage and re-aggregation potential. Results indicated that the responses of flocs to increasing shear force and breakage period depend on the coagulant used. The ability of floc to resist breakage decreased with the increase of shear force. Floc strength properties were also measured in response to increasing shear force, with the results suggesting that the order of floc strength was TiCl4 > FeCl3 > Al2(SO4)3. Floc regrowth of these three coagulants after exposure to high shear was limited, and flocs formed by TiCl4 displayed the weakest recoverability. Similar results were obtained when breakage period was different.
Zhao, YX, Gao, BY, Shon, HK, Wang, Y, Kim, J-H & Yue, QY 2011, 'The effect of second coagulant dose on the regrowth of flocs formed by charge neutralization and sweep coagulation using titanium tetrachloride (TiCl4)', JOURNAL OF HAZARDOUS MATERIALS, vol. 198, pp. 70-77.
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Characteristics of flocs formed by charge neutralization and sweep coagulation using titanium tetrachloride (TiCl4) were investigated with humic acidâkaolin suspension by continuous optical monitoring. This paper focused on the regrowth ability of broken flocs after addition of second TiCl4 dose. Variation of floc size and the fractal dimension of flocs versus second TiCl4 dose after regrowth were investigated. Second TiCl4 dose was added during the floc breakage period, and addition time of second TiCl4 dose was also investigated. The results showed that, when coagulated by charge neutralization at pH 6, an appropriate second TiCl4 dose improved regrowth ability of broken flocs at low initial TiCl4 doses. While for high initial TiCl4 doses, second TiCl4 dose lowered floc re-growth ability. When coagulated by sweep coagulation at pH 10, second TiCl4 dose made regrown flocs larger than those without second TiCl4 dose. Floc structure analysis showed that it was determined by not only the fractal dimension of flocs, but also the chemical characteristics of floc surface. Addition time of second TiCl4 dose had a great effect on floc regrowth ability, suggesting that the broken flocs had better regrowth when second TiCl4 dose was added at the end of the breakage period.
Zhu, XQ, Law, SS & Jayawardhan, M 2011, 'Experimental study on Statistical Damage Detection of RC Structures based on Wavelet Packet Analysis', Journal of Physics: Conference Series, vol. 305, pp. 012107-012107.
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Ahmad, A, Huang, S, Wang, JJ & Dissanayake, G 1970, 'A new state vector for range-only SLAM', 2011 Chinese Control and Decision Conference (CCDC), 2011 23rd Chinese Control and Decision Conference (CCDC), IEEE, Mianyang, Sichuan, China, pp. 3404-3409.
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This paper considers the simultaneous localization and mapping (SLAM) problem where the range-only sensor is used. Landmark initialization is a critical issue in range-only SLAM due to the lack of bearing information from the robot to the landmarks. A new state vector is proposed to be used in solving the range-only SLAM. In the new state vector, the landmark position is represented in different ways under different situations. This new representation avoids the need of multiple hypotheses on the landmark positions implemented in most of the existing range-only SLAM algorithms. Simulation and experimental results demonstrate the effectiveness of the new range-only SLAM algorithm using the new state vector within the least squares framework. © 2011 IEEE.
Altaee 1970, 'Forward Osmosis: Potential use in Desalination and Water Reuse', Journal of Membrane and Separation Technology, AIChE Annual Meeting, Lifescience Global.
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There has been a recurring interest in using Forward Osmosis (FO) process in water treatment and desalination. The recent advance in membrane technology has encouraged further investment in the process technology. Despite the promising results from pilot and bench scale experiments the technology is still not commercialized yet. Obviously, this is due to the complicated nature of the process which usually involves multiple stages of treatment in addition to the FO membrane process. Unfortunately, most of the recent studies were focused on studying the FO process alone and didn't provide enough data about the actual cost of the process as whole which includes the osmotic agent regeneration stage/s. This issue resulted in some uncertainties about the total cost of the water treatment by the process. Furthermore, more data are required to evaluate the impact of the osmotic agent losses on the overall cost and efficiency. More data are required to evaluate the effect of salt diffusion from seawater to the draw solution on the product water quality. This is particularly important due to the salt accumulation in the system when the draw solution is recycled and reused. In case if the draw solution is regenerated by membrane treatment, a suitable membrane should be selected to ensure an optimal salt rejection. For power generation by Pressure Retarded Osmosis (PRO) process, there was an evident progress. However, the process is site specific; i.e. it is dependent of the availability of the draw and donor solution. This suggested that the process is applicable to certain areas but can't be generalized. A quick review on the FO processes applications in water treatment and power generation is covered here to assess its potential use based on the recent development that have been made so far.
Altaee, A 1970, 'Alternative design to dual stage NF seawater desalination using high rejection brackish water membranes', Separations Division - Core Programming Topic at the 2011 AIChE Annual Meeting, pp. 23-39.
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Dual stage NF membrane desalination process was proposed as an alternative approach to RO seawater desalination. Despite of being cheaper than RO desalination, dual stage NF process is not commercially applied yet due to the low overall recovery rate. In an attempt to increase the process recovery rate and reducing the operation complicity, Brackish Water RO membrane was used instead of NF in the second stage. ROSA software was used in this study to verify the applicability and cost-effectiveness of the NF-BW dual stage desalination process. Similarly to dual stage NF desalination process, an NF membrane was used in the first stage and BW membrane in the second stage. Permeate from NF membrane was used as a feed into the BW membranes. The effect of membrane type and seawater salinity on the process performance was investigated. For any given recovery rate and seawater salinity, the simulation results showed that the overall cost of NF-NF was slightly lower than the NF-BW process but that was on the cost of higher permeate TDS. For instance, at 43000 mg/l feed salinity the difference in the specific power consumption between NF-NF and NF-BW process was 0.38 kWh/m3. The permeate TDS was 125 mg/l for NF-BW and 1030 mg/l for NF-NF process. The difference in the permeate TDS between NF-NF and NF-BW process increased with increasing the feed salinity. In dual stage NF process, a low permeate was achieved at low recovery rate. For example, at 43000 mg/l feed salinity the permeate TDS from dual stage NF process was 359 mg/l when the overall recovery rate was 22%. It was also found that the effect of BW membrane type on the process efficiency was insignificant. Finally, the energy requirements of NF-NF and NF-BW were compared to a single stage RO desalination process. The specific power consumption at 43000 mg/l feed salinity was 4.58 kWh/m3, 4.2 kWh/m3 and 3.86 kWh/m3 for RO, NF-BW and NF-NF process respectively.
Altaee, A 1970, 'Forward osmosis: Potential use in desalination and water treatment', International Congress on Energy 2011 - Topical Conference at the 2011 AIChE Annual Meeting, pp. 79-99.
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There has been a recurring interest in using Forward Osmosis (FO) process in water treatment and desalination. The recent advance in membrane technology has encouraged further investment in the process technology. Despite the promising results from pilot and bench scale experiments the technology is still not commercialized yet. Obviously, this is due to the complicated nature of the process which usually involves multiple stages of treatment in addition to the FO membrane process. Unfortunately, most of the recent studies were focused on studying the FO process alone and didn't provide enough data about the actual cost of the process as whole which includes the osmotic agent regeneration stage/s. This issue resulted in some uncertainties about the total cost of the water treatment by the process. Furthermore, more data are required to evaluate the impact of the osmotic agent losses on the overall cost and efficiency. More data are required to evaluate the effect of salt diffusion from seawater to the draw solution on the product water quality. This is particularly important due to the salt accumulation in the system when the draw solution is recycled and reused. In case if the draw solution is regenerated by membrane treatment, a suitable membrane should be selected to ensure an optimal salt rejection. For power generation by Pressure Retarded Osmosis (PRO) process, there was an evident progress. However, the process is site specific; i.e. it is dependent of the availability of the draw and donor solution. This suggested that the process is applicable to certain areas but can't be generalized. A quick review on the FO processes applications in water treatment and power generation is covered here to assess its potential use based on the recent development that have been made so far.
Altaee, A 1970, 'Forward osmosis: Potential use in desalination and water treatment', Catalysis and Reaction Engineering Division - Core Programming Topic at the 2011 AIChE Annual Meeting, pp. 100-120.
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There has been a recurring interest in using Forward Osmosis (FO) process in water treatment and desalination. The recent advance in membrane technology has encouraged further investment in the process technology. Despite the promising results from pilot and bench scale experiments the technology is still not commercialized yet. Obviously, this is due to the complicated nature of the process which usually involves multiple stages of treatment in addition to the FO membrane process. Unfortunately, most of the recent studies were focused on studying the FO process alone and didnt provide enough data about the actual cost of the process as whole which includes the osmotic agent regeneration stage/s. This issue resulted in some uncertainties about the total cost of the water treatment by the process. Furthermore, more data are required to evaluate the impact of the osmotic agent losses on the overall cost and efficiency. More data are required to evaluate the effect of salt diffusion from seawater to the draw solution on the product water quality. This is particularly important due to the salt accumulation in the system when the draw solution is recycled and reused. In case if the draw solution is regenerated by membrane treatment, a suitable membrane should be selected to ensure an optimal salt rejection. For power generation by Pressure Retarded Osmosis (PRO) process, there was an evident progress. However, the process is site specific; i.e. it is dependent of the availability of the draw and donor solution. This suggested that the process is applicable to certain areas but cant be generalized. A quick review on the FO processes applications in water treatment and power generation is covered here to assess its potential use based on the recent development that have been made so far.
AlTaee, A & Sharif, AO 1970, 'Alternative design to dual stage NF seawater desalination using high rejection brackish water membranes', Desalination, Elsevier BV, pp. 391-397.
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Dual stage NF membrane desalination process was proposed as an alternative approach to RO seawater desalination. Despite of being cheaper than RO desalination, dual stage NF process is not commercially applied yet due to the low overall recovery rate. In an attempt to increase the process recovery rate and reducing the operation complicity, Brackish Water RO membrane was used instead of NF in the second stage. ROSA software was used in this study to verify the applicability and cost-effectiveness of the NF-BW dual stage desalination process. Similarly to dual stage NF desalination process, an NF membrane was used in the first stage and BW membrane in the second stage. Permeate from NF membrane was used as a feed into the BW membranes. The effect of membrane type and seawater salinity on the process performance was investigated. For any given recovery rate and seawater salinity, the simulation results showed that the overall cost of NF-NF was slightly lower than the NF-BW process but that was on the cost of higher permeate TDS. For instance, at 43000 mg/l feed salinity the difference in the specific power consumption between NF-NF and NF-BW process was 0.38 kWh/m 3. The permeate TDS was 125 mg/l for NF-BW and 1030 mg/l for NF-NF process. The difference in the permeate TDS between NF-NF and NF-BW process increased with increasing the feed salinity. In dual stage NF process, a low permeate was achieved at low recovery rate. For example, at 43000 mg/l feed salinity the permeate TDS from dual stage NF process was 359 mg/l when the overall recovery rate was 22%. It was also found that the effect of BW membrane type on the process efficiency was insignificant. Finally, the energy requirements of NF-NF and NF-BW were compared to a single stage RO desalination process. The specific power consumption at 43000 mg/l feed salinity was 4.58 kWh/m 3, 4.2 kWh/m 3 and 3.86 kWh/m 3 for RO, NF-BW and NF-NF process respectively.
Ansari, YHH, Merifield, RS & Sheng, DC 1970, 'A numerical study on the applicability of the piezocone interpretation methods for hydraulic conductivity of clays', Computer Methods for Geomechanics: Frontiers and New Applications, pp. 442-448.
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During the last three decades, attempts have been made to obtain genuine interpretation methods for estimating the fl ow characteristics of fi ne grained soils through piezocone dissipation tests. Interpretation of these dissipation tests is however often based on various simplifying assumptions and has not been extensively calibrated against experimental or numerical results. In this research, piezocone penetration and dissipation tests are modelled numerically using large deformation fi nite element analysis with contact formulation. The effectiveness of the two widely used interpretation methods of Teh & Houlsby (1991) and Sully & Campanella (1994) is studied. It is found that the reliability of these methods is signifi cantly affected by the assumptions adopted. In addition, irrespective of their accuracy, the interpretation methods in the literature are found to be only applicable to normally consolidated to lightly overconsolidated soils.
Askari, M, Li, J & Samali, B 1970, 'Semi-Active LQG Control of Seismically Excited Nonlinear Buildings using Optimal Takagi-Sugeno Inverse Model of MR Dampers', Procedia Engineering, East Asia-Pacific Conference on Structural Engineering and Construction, Elsevier BV, Hong Kong, pp. 2765-2772.
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A novel semi-active control method for a seismically excited nonlinear benchmark building equipped with magnetorheological (MR) dampers is presented and evaluated in this paper. While Linear Quadratic Gaussian (LQG) controller is designed to estimate the optimal control force of a MR damper, the required voltage input for the damper to produce such control force is achieved by a proposed optimal Takagi- Sogeno(T-S) fuzzy inverse model. The proposed T-S fuzzy inverse model of dampers is derived using subtractive clustering, non-dominated sorting genetic algorithm II (NSGAII) and adaptive neuro-fuzzy inference systems (ANFIS). The effectiveness of this strategy is illustrated and verified using simulated response of a 20-storey full-scale nonlinear benchmark building excited by several historical earthquake records. The designed semi-active system is compared with the performances of active control as well as clipped optimal control (COC) systems, which are based on the same nominal controller as is used in this study. The results are discussed based on the evaluation criteria suggested for the benchmark problem by International Association for Structural Control and Monitoring (IASCM) for comparison with other algorithms and demonstrate the superiority of this scheme over other strategies.
Aslani, F & Nejadi, S 1970, 'A Comparison of the Bond Characteristics in Conventional and Self-Compacting Concrete, Part I: Experimental Results', 9th International Symposium on High Performance Concrete, International Symposium on High Performance Concrete, New Zealand Concrete Society, Rotorua, New Zealand, pp. 435-442.
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Self-compacting concrete (SCC) is a very flowing material that can flow through the reinforcement and fill the formworks without any need of vibration during the concrete placement process. The material properties of SCC including bond characteristics must be well understood in order to use this type of high performance concrete in structural members broadly. This paper presents a comparison of the experimental results from the nine recent investigations on the bond strength of SCC and conventional concrete (CC). The comparison is based on the measured bond between reinforcing steel and concrete by utilizing the pullout test on the embedded bars at various heights in mock-up structural elements to assess the top-bar effect and on single bars in small prismatic specimens and conducting the beam tests. The investigated affecting parameters on bond strength are: the steel bar diameter, concrete compressive strength, types of bar (plain or deformed), embedded length of the bar, concrete type, concrete cover, curing age of concrete, casting direction of concrete and height of the embedded bar along the formwork.
Aslani, F & Nejadi, S 1970, 'A Comparison of the Bond Characteristics in Conventional and Self-Compacting Concrete, Part II: Code Provisions and Empirical Equations', 9th International Symposium on High Performance Concrete, International Symposium on High Performance Concrete, New Zealand Concrete Society, Rotorua, New Zealand, pp. 443-450.
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Self-compacting concrete (SCC) is a highly workable concrete that flows through complex structural elements under its own weight. It is cohesive enough to fill the spaces of almost any size and shape without segregation or bleeding. This makes SCC become more practical wherever concrete placing is difficult, such as in heavily-reinforced concrete members or in complicated formworks. Bond behaviour between concrete and reinforcement is a primary factor in design of reinforced concrete structures. This study presents a comparison between code provisions and empirical equations with the experimental results from the recent studies on the bond strength of SCC and conventional concrete (CC). The comparison is based on the measured bond between reinforcing steel and concrete by utilizing the pullout test on the embedded bars at various heights in mock-up structural elements to assess the top-bar effect and on single bars in small prismatic specimens; and conducting the beam tests. The investigated varying parameters on bond strength are: the steel bar diameter, concrete compressive strength, concrete type, curing age of concrete and height of the embedded bar along the formwork.
Aslani, F & Nejadi, S 1970, 'Comparison of Creep Prediction Models for Self-Compacting and Conventional Concrete', 9th International Symposium on High Performance Concrete, International Symposium on High Performance Concrete, New Zealand Concrete Society, Rotorua, New Zealand, pp. 1-10.
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Realistic prediction of concrete creep is of crucial importance for durability and long-term serviceability of concrete structures. To date, research about the behaviour of self-compacting concrete (SCC) members, especially concerning the long-term performance, is rather limited. Hence, the realistic SCC creep strain prediction is an important requirement of the design process of this type of concrete structures. SCC is quite different from conventional concrete (CC) in mixture proportions and applied materials, particularly in the presence of aggregate which is limited. This paper reviews the accuracy of the creep prediction models proposed by six international codes of practice, including: CEB-FIP 1990, ACI 209R (1992), Eurocode 2 (2001), AASHTO (2004), AASHTO (2007) and AS 3600 (2009). The predicted creep strains are compared with actual measured creep strains in 60 mixtures of SCC and 17 mixtures of CC. The affecting parameters on the creep of SCC including: the water to binder ratio, binder to aggregate ratio, sand ratio, and curing age are investigated and discussed.
Aslani, F & Nejadi, S 1970, 'Comparison of Shrinkage Prediction Models for Self-Compacting and Conventional Concrete', 9th International Symposium on High Performance Concrete, 9th International Symposium on High Performance Concrete Committee, New Zealand Concrete Society, Rotorua, New Zealand, pp. 1-10.
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One of the reasons for the use of self-compacting concrete (SCC) is to improve the long-term behaviour and durability of concrete structures. However, shrinkage of SCC may be larger than conventional concrete (CC) because SCC has higher binder content and a lower coarse aggregate volume. Therefore, accurate prediction of the shrinkage deformation is an important aspect of the long term behaviour of concrete. In this study, experimental shrinkage results for 154 mixtures of SCC and 18 mixtures of CC are compared with the shrinkage strains that are calculated using the following models: CEB-FIP 1990, ACI 209R (1992), Eurocode 2 (2001), AASHTO (2004), AASHTO (2007) and AS 3600 (2009). The influence of various parameters, such as mixture design, cement content, filler content, aggregate content, and water cement ratio (w/c) on the shrinkage of SCC are also compared and discussed.
Aslani, F & Nejadi, S 1970, 'Comparison of the Analytical Models to Determine Modulus of Elasticity of Self-Compacting Concrete and Conventional Concrete', Structural Engineers World Congress 2011, Structural Engineers World Congress, SEWC, Como, Italy, pp. 1-11.
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Self-compacting concrete (SCC) can be placed under its own weight with no vibration efforts and is cohesive enough to be handled without segregation and bleeding. Modification in the mix design may have an influence on the materialâs mechanical properties. Therefore, it is important to investigate that whether all of the assumed hypotheses for conventional concrete (CC) to design the structures are also valid for SCC construction. Indubitably, the modulus of elasticity (MOE) is one of the most important mechanical properties which influences the durability and service life of reinforced concrete. MOE represents the stress-strain relationship of concrete in the elastic range and depends on the stiffness of the cement paste and aggregate, porosity, the interfacial transition zone, size of samples, and mixture proportions. This paper reviews the accuracy of the seven models for prediction of MOE for SCC and fifteen models for CC. The predicted MOE models are compared with the actual measured experimental values in 110 mixtures of SCC and 32 mixtures of CC.
Aslani, F & Nejadi, S 1970, 'Evaluation and Comparison of Analytical Models to Determine the Bond Characteristics of Steel Fibre Reinforced Self-Compacting Concrete', 9th International Symposium on High Performance Concrete, International Symposium on High Performance Concrete, New Zealand Concrete Society, Rotorua, New Zealand, pp. 1-8.
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Steel fibre reinforced self-compacting concrete (SFRSCC) can be placed and compacted under its self weight with little or no mechanical vibration. It is at the same time cohesive enough to be casted without segregation or bleeding. Steel fibres improve many of the properties of self-compacting concrete (SCC) elements including tensile strength, ductility, toughness, energy absorption capacity, fracture toughness and cracking. Although the available research regarding the influence of steel fibres on the properties of SFRSCC is limited, this paper investigates the bond characteristics between steel fibre and SCC. This by comparison of the five analytical models including (i.e. Naaman et al. (1991a,b), Dubey (1999), Cunha (2007), Soranakom (2008) and Lee et al. (2010)) with the experimental results from the four recently conducted single fibre pull-out tests. The influence of the fibre end hook, embedded length, fibre orientation angle, on the bond characteristic between fibre and SCC are determined and discussed. The accuracy of each analytical model also has been examined.
Aslani, F & Nejadi, S 1970, 'Evaluation and Comparison of the Analytical Models to Determine Tensile Strength of Self-Compacting Concrete and Conventional Concrete', Structural Engineers World Congress 2011, Structural Engineers World Congress, SEWC, Como, Italy, pp. 1-11.
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Differences in mixture proportions and applied materials between self-compacting concrete (SCC) and conventional concrete (CC) can result in an essentially effect on the physical properties and on the mechanical properties. Therefore, it is important to investigate that whether all of the assumed hypotheses for CC to design the structures are also valid for SCC construction. The tensile strength (TS) of concrete is important to predict the initiation of cracking of concrete members when it is subjected to external loads or by shrinkage alone. For design considerations, the shear, punching, anchorage, crack control, and minimum reinforcement directly depend on the tensile strength of the concrete. Relation between tensile and compressive strength of concrete changes by various factors including, the aggregate type and particle size distribution, age of the concrete, curing process and air content. This paper reviews the accuracy of the six models for SCC and nineteen models for CC for determining the TS of concrete. The predicted results are compared with the actual measured TS of concrete from the previously conducted experimental results in 86 mixtures of SCC and 26 mixtures of CC.
Aslani, F & Nejadi, S 1970, 'Evaluation and Comparison of the Analytical Models to Predict Creep and Shrinkage Behavior of Self-Compacting Concrete', Structural Engineers World Congress 2011, Structural Engineers World Congress, SEWC, Como, Italy, pp. 1-10.
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In the structures whose long-term behavior should be monitored and controlled, creep and shrinkage effects have to be included precisely in the analysis and design procedures. Creep and shrinkage, vary with the constituent and mixtures proportions, and depend on the curing conditions and work environment as well. Self-compacting concrete (SCC) contains combinations of various components, such as aggregate, cement, superplasticizer, water-reducing agent and other ingredients which affect the properties of the SCC including creep and shrinkage of the SCC. Hence, the realistic prediction creep and shrinkage strains of SCC are an important requirement of the design process of this type of concrete structures. In this study, three proposed creep models and four shrinkage models available in the literature are compared with the measured results of 52 mixtures for creep and 165 mixtures for shrinkage of SCC. The influence of various parameters, such as mixture design, cement content, filler content, aggregate content, and water cement ratio (w/c) on the creep and shrinkage of SCC are also compared and discussed.
Aslani, F & Nejadi, S 1970, 'Evaluation of Experimental Results to Determine the Bond Characteristics of Steel Fiber Reinforced Self-Compacting Concrete', Structural Engineers World Congress 2011, Structural Engineers World Congress, SEWC, Como, Italy, pp. 1-8.
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Steel fibers can improve many of the properties of self-compacting concrete (SCC) elements including tensile resistance and crack control, ductility, toughness, energy absorption capacity, and resistance to fatigue. However, the structural behavior depends on the composite action of the concrete and steel in resisting the external loads. If steel fiber undergoes the same strain or deformation as the surrounding concrete, no slip occurs between the two materials under load and a prefect bond exists. Indubitably, prediction of accurate behavior of the composite material requires precise modeling and determining of the bond characteristics. In fiber reinforced concrete (FRC), the interface between fiber and cement paste is the weakest link of the micro-structure. Therefore, the study of the behavior of fiber-paste interface is vital for understanding the mechanism of the composite behavior. This paper presents a comparison of the experimental results from the four recent investigations on the bond characteristics of steel fiber reinforced self-compacting concrete (SFRSCC). The comparison is based on the measured bond stresses between steel fiber and SCC by utilizing a single fiber pullout test. The influences of the fiber end hook, embedded length, fiber orientation angle, concrete age, and concrete cover on the pullout test of the fibers were also investigated.
Azari, B, Fatahi, B & Khabbaz, H 1970, 'Application of Creep Ratio Concept for Estimating Post-Constriction Settlement of Deep Soft Clay Deposits', ICAGE 2011 - Proceedings of the International Conference on Advances in Geotechnical Engineering, International Conference on Advances in Geotechnical Engineering, Curtin University, Perth, Australia, pp. 127-133.
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Two main different approaches have been previously proposed to predict time dependent behaviour of soft soils. (I) end of primary consolidation is unique although creep starts simultaneously with primary consolidation (Hypothesis A); (II) As creep and primary consolidation commence at the same time and creep is a time dependant phenomenon, then end of primary consolidation cannot be unique (Hypothesis B). In Hypothesis A, soil settlement is divided into two parts: primary consolidation and secondary compression which follows by primary consolidation. In Hypothesis B, soil settlement is estimated based on elasto-viscoplastic constitutive model simulating soil creep and consolidation settlement simultaneously. In this study, details of first approach based on creep ratio ( ) concept is discussed with a worked example to be used by practicing geotechnical engineers.
Ball, JE, Babister, MK & Retallick, ME 1970, 'Revisiting the design flood problem', 34th IAHR Congress 2011 - Balance and Uncertainty: Water in a Changing World, Incorporating the 33rd Hydrology and Water Resources Symposium and the 10th Conference on Hydraulics in Water Engineering, Congress of IAHR, the International Association of Hydro-Environment Engineering and Research, Engineers Australia, Brisbane, Australia, pp. 31-38.
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While previous editions of ARR have served the engineering profession well, a number of issues have necessitated the production of a new edition. These issues include the many recent developments in knowledge about rainfall-runoff processes, the increased computational capacity available to engineering hydrologists, and the rapidly expanding body of information about climate change. As part of the development of the new edition, it has been necessary to look at the history of methods used and the implications of assumptions necessary for implementation of these methods. Arising from this review, a way forward for design flood estimation in Australia is proposed that addresses many of the simplifying assumptions inherent in past methods for flood estimation but also recognises the differing levels of complexity required for design flood estimation. This new vision for design flood estimation will be incorporated in the new edition of ARR.
Bastidas-Arteaga, E, Schoefs, F & Stewart, M 1970, 'Considerations for probabilistic assessment of the effect of global warming on durability of corroding RC structures', Applications of Statistics and Probability in Civil Engineering -Proceedings of the 11th International Conference on Applications of Statistics and Probability in Civil Engineering, CRC Press, pp. 2102-2110.
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Chloride ingress and carbonation cause corrosion of Reinforcing Concrete (RC) structures affecting its operational life. Experimental evidence indicates that these deterioration processes are highly influenced by weather conditions in the surrounding environment-i.e. temperature, humidity, CO2 emissions, etc. Since studies on global warming announce several changes in climate, the impact of climate on RC durability should be also considered. This paper links RC deterioration mechanisms and global warming. To consider this interaction, it has been defined based on appropriate deterioration models. Based on various studies on climate change, models for estimating the effect of global warming on temperature, humidity and CO2 emissions are also described. Furthermore, various scenarios of global warming that can be used to assess the effect of climate change in structural reliability are proposed. These scenarios take into account: gas emissions, global population growth, introduction of new and clean technologies and use of fossil sources of energy. The proposed approach is illustrated with a numerical example. The last part of the paper outlines some adaptation strategies focusing particularly on the needs for the selection of an optimal adaptation strategy © 2011 Taylor & Francis Group, London.
Bjarnadottir, S, Li, Y & Stewart, M 1970, 'Probabilistic-based assessment of the impacts of climate change on hurricane loss and adaptation strategies', Applications of Statistics and Probability in Civil Engineering -Proceedings of the 11th International Conference on Applications of Statistics and Probability in Civil Engineering, CRC Press, pp. 2094-2101.
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This paper presents a risk-cost-benefit based framework to assess the potential hurricane damage risks to residential construction and investigate the cost-effectiveness of different adaptation strategies under various wind speed change scenarios due to climate change. It is estimated that hurricanes caused $6 billion annually in the US in recent years. Changes in hurricane intensity or/and frequency may be expected due to the changing climate. This paper proposes a framework to refine hurricane risk assessment by accounting for the impacts the changing climate may have on hurricane intensity and/or frequency. Various adaptation strategies will be developed in an attempt to mitigate damage costs. Three case study locations (Miami-Dade County, New Hanover County, Galveston County) are presented. This study finds that climate change may have a substantial impact on damage estimation in coastal areas, and that certain adaptation strategies can cost-effectively decrease the damage © 2011 Taylor & Francis Group, London.
Coorey, BP & Jupp, JR 1970, 'PARAMETRIC MODELLING AND DESIGN PROCESES Exploring synthesis and evaluation using a Function-Behaviour-Structure perspective', PROCEEDINGS OF THE 16TH INTERNATIONAL CONFERENCE ON COMPUTER-AIDED ARCHITECTURAL DESIGN RESEARCH IN ASIA (CAADRIA 2011), Association for Computer-Aided Architectural Design Research in Asia (CAADRIA) annual conference, The Association for Computer-Aided Architectural Design Research in Asia, The University of Newcastle, Australia, pp. 39-48.
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In an attempt to extend our understanding of the design process in the context of computational parametric design tools, this paper explores the relationship between and interaction of synthesis and evaluation. In establishing the importance of their coupling in parametric design the paper then explores its consequence on the design process relative to existing models of designing. A tension between designing as planning, search and exploration in parametric design is highlighted together with a conceptual framework, which draws from a situated Function-Behaviour-Structure model of design. The purpose of the framework is to facilitate these different modes of designing and is targeted at the use of parametric tools.
Crews, KI, Buchanan, AH, Quenneville, P & Pampanin, S 1970, 'Development of High Performance Structural Timver Systems for Non Residential Buildings in New Zealand and Australia', Procedia Engineering, Structural Engineering and Construction Conference, Elsevier BV, Hong Kong, pp. 1582-1589.
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Design of structural systems for commercial and multi-residential buildings throughout most parts of the world, is currently dominated by the use of reinforced and / or prestressed concrete construction, usually supported by steel or concrete beams and frames. However, recent developments throughout the world have demonstrated the potential for timber based structural systems to be used in these types of buildings for beams and columns, roof structures and floors. The advent of engineered wood products (EWP's) such as LVL and glulam has made it possible to fabricate large section, long spanning structural members that have excellent structural properties and reliability equivalent to that of steel or concrete used in the same applications. Since 2007, significant (and related) research initiatives have been undertaken in Australia and New Zealand, investigating the performance of timber and timber hybrid systems for use in large span / medium rise commercial and industrial buildings. In 2009 a research consortium of government, industry and three Universities known as the Structural Timber Innovation Company (STIC) commenced an extensive R&D 5 year program with a total budget of $10m NZD
Diao, C, Zhou, Q & Zhou, JL 1970, 'Growth Responses and Phytoremediation Characteristics of Mirabilis Jalapa L. in Benzo[a]pyrene and Pyrene Co-contaminated Soils', Advances in Intelligent and Soft Computing, Conference on Advances in Computer Science, Intelligent System and Environment, Springer Berlin Heidelberg, Guangzhou, PEOPLES R CHINA, pp. 397-403.
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Pot culture experiments were conducted to investigate the effect of Benzo[a]pyrene(B[a]P) and pyrene on seed germination and growth factors of Mirabilis Jalapa L. and their uptake, accumulation and dissipation. The results showed that B[a]P and pyrene at the lower concentrations could accelerate seed germination and photosynthesis rate. There weren't significant relationships between shoot height, root length, or biomass and the concentrations of B[a]P and pyrene in soil. The relative absorptivity of B[a]P and pyrene in roots of M. Jalapa was less than 11%. But the amount of B[a]P and pyrene in shoots was close to zero. The relative removal rate of B[a]P and pyrene was up to 83-99% and 5-98%, respectively. Therefore, Plant-promoted rhizomorph biodegradation is the dominant contribution to remove B[a]P and pyrene. M. Jalapa might be useful for phytoremediation of B[a]P and pyrene co-contaminated sites. © 2011 Springer-Verlag Berlin Heidelberg.
Far, H, Fatahi, B & Samali, B 1970, 'Effects of Dynamic Soil-Structure Interaction on Performance Level of Moment Resisting Buildings Resting on Different Types of Soil', Proceedings of the 2011 Pacific Conference on Earthquake Engineering (PCEE), Pacific Conference on Earthquake Engineering (PCEE) - 'Building an Earthquake Resilient Society', New Zealand Society for Earthquake Engineering Inc., New Zealand, pp. 1-8.
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In this study, two structural models comprising five and fifteen storey moment resisting building frames are selected in conjunction with three different soil deposits with shear wave velocity less than 600m/s. The design sections are defined after applying dynamic nonlinear time history analysis based on inelastic design procedure using elastic-perfectly plastic behaviour of structural elements. These frames are modelled and analysed employing Finite Difference approach using FLAC 2D software under two different boundary conditions namely fixed-base (no soil-structure interaction), and considering soil-structure interaction. Fully nonlinear dynamic analyses under the influence of different earthquake records are conducted and the results of inelastic behaviour of the structural models are compared. The results indicate that the inter-storey drifts of the structural models resting on soil types De and Ee (according to the Australian standard) substantially increase when soil-structure interaction is considered for the above mentioned soil types. Performance levels of the structures change from life safe to near collapse when dynamic soil-structure interaction is incorporated. Therefore, the conventional inelastic design procedure excluding SSI is no longer adequate to guarantee the structural safety for the building frames resting on soft soil deposits.
Fatahi, B & Khabbaz, H 1970, 'Enhancement of Ballasted Rail Track Performance Using Geosynthetics', Advances in Pile Foundations, Geosynthetics, Geoinvestigations, and Foundation Failure Analysis and Repairs, GeoHunan International Conference 2011, American Society of Civil Engineers, Hunan, China, pp. 222-230.
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The requirement of keeping a competitive edge against other means of transportation has increased the pressure on the railway industry to improve its efficiency and decrease the maintenance costs. In this paper, several solutions are presented to improve rail track foundations including optimum particle ballast grading and confining pressure as well as stabilising tracks overlying soft soils employing different techniques. This study specifically assesses the influence of shoulder ballast and its combination with geosynthetics to reduce the track settlement due to train load. Two dimensional plane strain finite element model is adopted to simulate the track deformation. Furthermore, the potential use of geosynthetics combined with recycled and blended ballast for reduction of rail displacement is addressed. The different location of geosynthetics in rail track substructure is examined. Rail track performance can be improved by including wider shoulder ballast with geosynthetic layer, and recycled and blended ballast reinforced with geosynthetics can be used during maintenance operation to curtail future track deformation. © 2011 ASCE.
Fatahi, B, Tabatabaiefar, HR & Samali, B 1970, 'Performance Based Assessment of Dynamic Soil-Structure Interaction Effects on Seismic Response of Building Frames', GeoRisk 2011, Georisk 2011, American Society of Civil Engineers, Atlanta, Georgia, USA, pp. 344-351.
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Soil-Structure Interaction (SSI) has progressed rapidly in the second half of 20th century stimulated mainly by requirements of the nuclear power and offshore industries to improve the seismic safety. In this study, a fifteen storey moment resisting building frame is selected in conjunction with three different soil deposits with shear wave velocity less than 600m/s. The design sections are defined after applying dynamic nonlinear time history analysis based on inelastic design procedure using elastic-perfectly plastic behaviour of structural elements. These frames are modelled and analysed employing Finite Difference approach using FLAC 2D software under two different boundary conditions, namely fixed-base (no soil-structure interaction), and considering soil-structure interaction. Fully nonlinear dynamic analyses under the influence of different earthquake records are conducted and the results of inelastic behaviour of the structural model are compared. Variations of the shear modulus ratio with the shear strain are included in the nonlinear dynamic analysis. The results indicate that the inter-storey drifts of the structural model resting on soil types De and Ee (according to the Australian standard) substantially increase when soil-structure interaction is considered for the above mentioned soil types. Performance levels of the structures change from life safe to near collapse when dynamic soil-structure interaction is incorporated. Therefore, the conventional inelastic design procedure excluding SSI is no longer adequate to guarantee the structural safety for the building frames resting on soft soil deposits. Design engineers need to address the effects of dynamic SSI precisely in their design especially for construction projects on soft soils.
Forsythe, PJ, Jupp, JR & Sawhney, A 1970, 'BIM in Tertiary Construction Project Management Education: A Program Wide Strategy', 36th Annual Conference for Australasian University Building Educators Association, Australian Universities Building Education Association Annual Conference, Institute of Sustainable Development & Architecture, Bond University, Gold Coast, Australia, pp. 192-211.
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This paper reports on the ongoing research and development of teaching and learning supported by Building Information Modelling (BIM) in the undergraduate Construction Project Management (CPM) Program at the University of Technology Sydney (UTS). At its heart, BIM is used to facilitate a more integrated and visual mode of teaching. It provides a new basis for developing problem based learning - one that has the potential to allow students to aggregate their learning around a central project whilst allowing problems to be scaled at different levels of complexity. This approach aims to better integrate and link individual subjects together as well as improve the development of core student attributes such as communication, understanding, decision making, collaboration and information gathering skills; very much mimicking the ongoing BIM driven transformation happening in the industry. The BIM models aim to be regularly used in various formats as students progress through their undergraduate degree Program - and we adopt the term 'vertical problems' to capture the way BIM models and problem based learning can be utilised throughout the Program. Here, lecturers are able to author 'sub- plots' that utilise BIM models in a way that best suits their specific subjects, e.g. cost, time, quality, sustainability subject areas. To this end, the paper reports on findings from the research, development and early implementation stages of a program wide teaching and learning proposition supported by BIM. This includes a typology that helps target varying degrees of BIM utilization and diffusion in given subjects and transitional requirements for both staff and students.
Fukumoto, T, Thomas, P, Stuart, BH, Adam, G, Simon, P, Shimmon, R & Guerbois, JL 1970, 'Kinetic and mechanistic analysis of the polymerisation of dimethylol urea', Proceedings of the 3rd Joint Czech-Hungarian-Polish-Slovak Thermoanalytical Conference, Slovak Chemical Society, Stara Lesna, pp. 1-5.
Geng, XY, Indraratna, B & Rujikiatkamjorn, C 1970, 'Consolidation of Ground with Partially Penetrated PVDs Combined with Vacuum Preloading', Geo-Frontiers 2011, Geo-Frontiers Congress 2011, American Society of Civil Engineers, pp. 567-575.
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Partially penetrating prefabricated vertical drain (PVDs) with a combined surcharge and vacuum preloading are considered in this paper. The analysis results can be used in cases where the soft soil clay is too deep and not economical to be penetrated to full depth, or the surcharge preloading is too small to justify full penetration of soft clay layer or the vacuum pressure can be lost, which is caused by the permeability of the bottom of the clay for the fully penetrated drain etc. In this model, a virtual vertical drain is assumed to reflect the real three-dimensional seepage in the soil beneath the tip of PVD instead of using the traditional one-dimensional consolidation theory, and at the same time, the well-resistance and the smear zone can be also considered. The vacuum pressure distribution is assumed to be no loss along the drain, whereas a zero pore pressure boundary condition is assumed at the interface between the bottom clay layer and the lower drainage layer. The proposed solutions are then employed to analyze a case history. © ASCE 2011.
Grassman, TJ, Carlin, AM, Swaminathan, K, Ratcliff, C, Grandal, J, Yang, L, Mills, MJ & Ringel, SA 1970, 'Expanding the palette: Metamorphic strategies over multiple lattice constant ranges for extending the spectrum of accessible photovoltaic materials', 2011 37th IEEE Photovoltaic Specialists Conference, 2011 37th IEEE Photovoltaic Specialists Conference (PVSC), IEEE.
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Guo, W 1970, 'Impact assessment of extra discharges of organics and nutrients into aquatic systems by entropy calculation', CESE 2011, The Fourth Annual Conference on the Challenges in Environmental Science and Engineering, CESE Conference Committee, Tainan City, Taiwan, pp. 13-94.
Guo, W 1970, 'Optimisation of an integrate sponge - granular activated carbon fluidized bed bioreactor in secondary sewage treatment', CESE 2011, The Fourth Annual Conference on the Challenges in Environmental Science and Engineering, CESE Conference Committee, Tainan City, Taiwan, pp. 75-76.
Guo, W 1970, 'Risk control and environment based assessment of recycled water schemes in australia', CESE 2011, The Fourth Annual Conference on the Challenges in Environmental Science adn Engineering, CESE Conference Committee, Tainan, Taiwan, pp. 4-85.
Hamedanimojarrad, P, Adam, G, Ray, AS, Vessalas, K & Thomas, PS 1970, 'Development of shrinkage resistant cement-based materials using fibers', ISEC 2011 - 6th International Structural Engineering and Construction Conference: Modern Methods and Advances in Structural Engineering and Construction, International Structural Engineering and Construction Conference, Research Publishing, Zurich, Switzerland, pp. 1193-1198.
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Drying shrinkage is themajor contributor to volume changes in normal strength concrete. Several classes of shrinkage compensating admixtures are known to the concrete industry. This study deals with the literature review and categorization of different classes of shrinkage reducing fibers, especially polyethylene fibers, with the objective of introducing new types of shrinkage reducing fiber. In this investigation a special type of hydrophobic polyethylene minifibers has been used in different dosages in mortar samples. The experimental results on drying shrinkage aswellasonseveralotherpropertiesarereported.Thehydrophobicminifibersshowedremarkable improvement in shrinkage reduction even at very lowconcentrations (0.1%of cementweight).
Hamedanimojarrad, P, Ray, AS, Adam, G, Thomas, P & Vessalas, K 1970, 'Evaluation of a hybrid system of admixture and fibre for development of shrinkage resistant cement-based material', 9th International Symposium on High Performance Concrete - Design, Verification & Utilization - Proceedings (TR48), International Symposium on High Performance Concrete, New Zealand Concrete Society (NZCS), Rotorua, NZ, pp. 1-8.
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Shrinkage is a crucial feature in concrete and mortar members as it results in volume change that can lead to cracking and consequently to serviceability problems. Different additives and methods have been proposed to compensate for this problem mainly through the use of shrinkage reducing admixtures, fibres and expansive agents. In this paper, several combination systems of polyethylene micro-fibre along with an inorganic expansive agent have been studied for their influence on drying shrinkage. This special type of fibre, reported to act as shrinkage reducer, had been used in different concentrations in mortars and had been shown to have advantages and disadvantages. On the other hand, expansive agent, ammonium polyphosphate, had been shown to reduce drying shrinkage and modify most of mechanical properties. Free shrinkage strains as well as some physical properties of new mixes which contain polyphosphate and polyethylene micro-fibre are reported in this study. Several combinations were used and have been shown to have promising results in drying shrinkage, physical and mechanical properties.
Holmes, MI, Crews, KI & Ding, GK 1970, 'The influence building codes and fire regulations have on multi-storey timber construction in australia', World Sustainable Building Conference, World Sustainable Building Conference, Finish Association of Civil Engineers RIL & VTT Technical Research Centre of Finlandn, Helsinki, Finland, pp. 224-235.
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Timber is an environmentally friendly building material that is both renewable and reusable, though being combustible by nature meant historically it has been viewed in some parts of the world as an inferior structural material to steel and concrete in multi-storey construction. Buildings are responsible for a substantial amount of material and energy consumption. The environmental properties of materials aren't traditionally a design or construction priority and typically cost, performance characteristics and aesthetics have governed the choice of structural materials. This trend is beginning to change as the issues associated with climate change continue to come to the forefront and governments and industry look for ways to assuage its effects. Choosing environmentally sustainable building materials is beginning to become a client and tenant expectation and industry is starting to follow suit. Life Cycle Assessment studies have outlined when timber is used as an alternative structural material to steel and concrete the overall environmental impact of the building can be reduced.
HU, H, WANG, J & LI, Y 1970, 'INVESTIGATION ON ITS VIBRATION-REDUCTION AND SHOCK-RESISTANT PROPERTIES OF A GUN RECOIL MECHANISM BASED ON MR DAMPER', Electro-Rheological Fluids and Magneto-Rheological Suspensions, Proceedings of the 12th International Conference, WORLD SCIENTIFIC, Philadelphia, Pennsylvania, USA, pp. 214-220.
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MR damper has brought out new challenges for development of the recoil mechanisms and vibration stability control of weapons because of its good electromechanical coupling performances. At present, it has been an urgent task during automatic firing to ensure its dynamic performance and its reliability of gun recoil mechanism under continuous fastly impact. For recoil mechanisms applications, MR dampers are desired to provide optimal damping force to control the recoil dynamics, so that large peak of recoil forces can be avoided with a certain limited stroke, and the firing stillness and stability are ensured. According to its vibration and shock mechanics process of gun recoil mechanism, the measurement method of its vibration-reduction and shock-resistant properties of gun recoil mechanism based on MR damper is analyzed. The results show that a gun recoil mechanism based on MR damper is quite a good vibration-reduction and shock-resistant equipment when the vibration and shock energy dissipation by damp is considered.
Indraratna, B & Nimbalkar, S 1970, 'Implications of ballast breakage on ballasted railway track based on numerical modeling', Computer Methods for Geomechanics: Frontiers and New Applications, International Conference of the International Association for Computer Methods and Advances in Geomechanics, Melbourne, Australia, pp. 1085-1092.
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Large and frequent cyclic train loading from heavy haul and passenger trains often leads to progressive track deterioration. The excessive deformation and degradation of ballast and unacceptable differential settlement of track and/or pumping of underlying soft subgrade soils necessitate frequent and costly track maintenance. A proper understanding of load transfer mechanisms and subsequent deformations in track layers is the key element for safe and economical track design and optimum maintenance procedures. Many simplifi ed analytical and empirical design methods have been used to estimate the settlement and stress-transfer between the track layers. However, these design methods are based on the linear elastic approach, and often only give crude estimates. Given the complexities of the behaviour of the composite track system consisting of rail, sleeper, ballast, sub-ballast and subgrade subject to repeated traffi c loads in a real track environment, the current track design techniques are overly simplifi ed. The track design should also account for the deterioration of ballast due to breakage and subsequent implications on the track deformations. Considering this, an elasto-plastic constitutive model of a composite multi-layer track system is proposed. Constitutive models and material parameters adopted in this numerical model are discussed. A hardening soil model with a non-associative fl ow rule is introduced to accurately simulate the strain-hardening behaviour of ballast. The breakage of ballast observed in large scale triaxial tests is also simulated based on this model. In conjunction, numerical simulations are also performed using a two-dimensional plane-strain fi nite element analysis (PLAXIS) capturing the effects of ballast breakage and track confi ning pressure. The paper also demonstrates the advantages of the proposed elasto-plastic fi nite element simulations when compared to conventional analytical methods used by practitioners that are...
Indraratna, B, Regmi, G, Nghiem, LD & Golab, A 1970, 'Geo-Environmental Approaches for the Remediation of Acid Sulphate Soil in Low-Lying Floodplains', Geo-Frontiers 2011, Geo-Frontiers Congress 2011, American Society of Civil Engineers, pp. 856-865.
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Acidity generated from the oxidation of pyrite and other sulphidic compounds that exist at shallow depths in acid sulphate soils (ASS) presents a challenging environmental problem in coastal Australia. The generated acidic groundwater can adversely impact coastal ecosystems, aquaculture and agriculture. Groundwater manipulation using weirs and modified floodgates in creeks and flood mitigation drains in ASS-affected farmland, which has been practiced for over a decade for preventing pyrite oxidation, is not effective in low-lying floodplains due to the high risk of flooding. In this paper, the authors present an overview of their experience in coastal Australia, a critical evaluation of currently practiced geo-environmental remediation methods as well as a demonstration of a pilot permeable reactive barrier (PRB) to control acidic groundwater pollution. The selection of recycled concrete, a commonly available alkaline waste material, and the systematic investigation of its longevity are highlighted through a series of batch and column experiments. In addition, the improvement of the groundwater quality by a pilot PRB using recycled concrete in ASS terrain within the Shoalhaven region of NSW, Australia will be elucidated based on field data collected over the last 3.5 years. © ASCE 2011.
Indraratna, B, Rujikiatkamjorn, C & Jing, N 1970, 'Cyclic Behaviour of Soft Soil Subgrade Improved by Prefabricated Vertical Drains', DEFORMATION CHARACTERISTICS OF GEOMATERIALS, PTS 1 AND 2, 5th International Symposium on Deformation Characteristics of Geomaterials (IS), IOS PRESS, Seoul, SOUTH KOREA, pp. 559-564.
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Indraratna, B, Rujikiatkamjorn, C & Nimbalkar, S 1970, 'Use of Geosynthetics in Railways Including Geocomposites and Vertical Drains', Geo-Frontiers 2011, Geo-Frontiers Congress 2011, American Society of Civil Engineers, Dallas, Texas, pp. 4733-4742.
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Australia relies heavily on rail for the transportation of bulk commodities and passenger services, and has introduced faster and heavier trains in recent years due to a growing demand. Large cyclic loading from heavy haul and passenger trains often leads to progressive deterioration of the track. The excessive deformations and degradations of the ballast layer and unacceptable differential settlement or pumping of underlying soft and compressible subgrade soils necessitate frequent costly track maintenance works. A proper understanding of load transfer mechanisms and their effects on track deformations are essential prerequisites for minimising maintenance costs. The reinforcement of the track by means of geosynthetics leads to significant reduction in the downward propagation of stresses and assures more resilient long-term performance. The geocomposite serves the functions of reinforcement, drainage and separation, thereby reducing the vertical and lateral deformations. Stabilization of soft subgrade soils by using prefabricated vertical drains (PVDs) is also essential for improving the overall stability of track and to reduce the differential settlement during the operation of trains. The effectiveness of using geocomposite geosynthetic and PVDs has been observed through field measurements and finite element analyses. These have been the first fully instrumented, comprehensive field trials carried out in Australian Railways, and it was very encouraging to see the field observations matching the numerical predictions. © ASCE 2011.
Indraratna, B, Rujikiatkamjorn, C, Vinod, JS & Nimbalkar, S 1970, 'PHYSICAL AND CHEMICAL GROUND IMPROVEMENT FOR SUSTAINABLE TRANSPORTATION INFRASTRUCTURE UNDER CYCLIC LOADS', Geotechnical Engineering for Disaster Mitigation and Rehabilitation and Highway Engineering 2011, Proceedings of the 3rd and 5th International Conference, WORLD SCIENTIFIC, Semarang, INDONESIA, pp. 140-156.
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Jayawardhana, M, Zhu, X & Liyanapathirana, R 1970, 'Structural Damage Detection of RC Structures using AR Model Coefficients', DYNAMICS FOR SUSTAINABLE ENGINEERING, VOL 1, 14th Asia Pacific Vibration Conference (APVC) on Dynamics for Sustainable Engineering, HONG KONG POLYTECHNIC UNIV, Hong Kong, PEOPLES R CHINA, pp. 298-306.
Jenkins, D, McCarthy, LM & Baweja, D 1970, 'Optimising precast bridge girders for sustainability with the use of high performance concrete', Proceedings of the 9th International Symposium on High Performance Concrete - Design, Verification & Utilization (TR48), International Symposium on High Performance Concrete, New Zealand Concrete Society (NZCS), Rotorua, NZ, pp. 1-7.
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The standard Super-T bridge girders used in Australia were developed to provide optimum performance at a time when the maximum concrete grade covered by the bridge design code was 50 MPa. This paper examines the opportunities for improved sustainability through the use of high performance concrete, considering the use of existing standard sections, modified sections optimised for higher strength grades, and the use of techniques such as hybrid pre-tensioned and post-tensioned girders, and precast girders used in continuous structures. These alternatives are compared for impact on CO2 emissions within the context of current Australian precast and bridge construction practice. In addition, the designs of the sections are reviewed based on a series of alternative concrete mix designs covering a reference Portland cement concrete mix and a series of concretes incorporating a range of supplementary cementitious materials included at different levels of cement replacement to determine efficiencies in design and impacts on the embodied energy required to manufacture the elements.
Jupp, JR 1970, 'DECISION PROCESSES IN ENGINEERING DESIGN: A NETWORK PERSPECTIVE OF STAKEHOLDER AND TASK INTERACTION', PROCEEDINGS OF THE 18TH INTERNATIONAL CONFERENCE ON ENGINEERING DESIGN (ICED 11): IMPACTING SOCIETY THROUGH ENGINEERING DESIGN, VOL 9: DESIGN METHODS AND TOOLS, PT 1, International Conference on Engineering Design (ICED), The Design Society, Danmarks Tekniske Universitet, Danmarks Tekniske Universitet, Copenhagen, Denmark.
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In recent years, there has been significant attention given to developing decision support methods and tools for engineering design. While advances in the formal, mathematical modeling and statistical mechanics based models have been impressive, this has not been the case for research attempting to reach beyond normative models to examine the cognitive and social factors that influence decision-making. In general advances have provided for either a top-down or bottom-up approach to decision-making; ignoring the requirements for both participant and task connectedness and dependencies. This paper describes an integrated modeling framework that uses a multi-network perspective of decision-making. The utility and extensibility of this framework are considered in discussion by way of examples from construction engineering design.
Keshavarzi, A & Ball, J 1970, 'Transition Probability of the Coherent Turbulent Flow around a Circular Bridge Pier', World Environmental and Water Resources Congress 2011, World Environmental and Water Resources Congress 2011, American Society of Civil Engineers, Palm Springs, California, USA, pp. 2478-2487.
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The coherent structure of flow around a single circular bridge pier and its effects on bed scouring pattern is investigated in this study. The bursting events and associated shear stresses play a major role in sediment entrainment from the bed and in particular around a bridge pier. In this study, the three-dimensional velocity of flow was measured at 102 points near the bed of an open channel using Acoustic Doppler Velocity meter (Micro-ADV). The pattern of scouring and bed profile was measured during the experimental test. The three-dimensional analyse of bursting process and Markov process was applied to the velocity data to find the sequential occurrence of bursting events and to recognize the transition probability of internal and external sweep events. The results showed that external sweep event was very effective mechanism for sediment entrainment close around a single circular bridge. © 2011 ASCE.
Keshavarzi, A, Gholamreza, M & Ball, JE 1970, 'Stochastic modelling of bursting process at threshold conditions', 34th IAHR Congress 2011 - Balance and Uncertainty: Water in a Changing World, Incorporating the 33rd Hydrology and Water Resources Symposium and the 10th Conference on Hydraulics in Water Engineering, Congress of IAHR, the International Association of Hydro-Environment Engineering and Research, Engineers Australia, Brisbane, Australia, pp. 3553-3560.
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In this paper, a stochastic model for analysis of the occurrence of bursting events and entrainment of sediment particles from the bed at the threshold of sediment motion is presented. This study focused on the modeling of turbulent bursts (i.e., the cycle of sweeps, ejections, and inward and outward interactions). From the collected experimental data, a transition probability is presented using Markov process. Using this information about bursting events, a Markov model is presented for the incipient motion of sediment particles. Validation of this model for particle motion was obtained using an image processing technique. Good agreement was found between the predicted number of entrained sediment particles and the observed numbers of particles.
Kreit, A, Castel, A, Francois, R & Al-Mahmoud, F 1970, 'Behaviour of damaged RC beams repaired with NSM CFRP rods', Concrc - Proceedings of Concrete Solutions, 4th International Conference on Concrete Repair, 4th International Conference on Concrete Repair, CRC Press, Dresden, GERMANY, pp. 705-716.
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The deterioration of reinforced concrete RC structures due to continual upgrading of service loads has resulted in a large number of structures that need repair. In this paper, an experimental program presented studies the possibility of using a Near Surface Mounted (NSM) CFRP rod to repair RC beams damaged by overloading. Several beam specimens were built. Some specimens were repaired after preloading condition and the other ones were repaired under sustained load. One beam specimens were strengthened by composite rods before loading. The main goal of this work is to investigate the influence of initial load and sustained load on flexural behaviour of RC beams repaired with an NSM CFRP rod system. The main experimental parameters include different levels of damage and sustained load. Test results in the current study show that the maximum load-carrying capacity of repaired beams at different levels of sustained load generally performed very close to that of the initially strengthened beam. Beams repaired at higher levels of sustained load failed by crushing of concrete, because there is an important level of compression strain in concrete due to sustained load. © 2012 Taylor & Francis Group.
Le, T, Fatahi, B & Khabbaz, H 1970, 'Soil Creep Mechanisms and Inducing Factors', ICAGE 2011 - Proceedings of the International Conference on Advances in Geotechnical Engineering, International Conference on Advances in Geotechnical Engineering, Curtin University, Perth, Australia, pp. 241-246.
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Soft soils have been utilised intensively for urbanisation and civil infrastructural development due to the scarcity of proper soils for construction. Soft soils themselves exhibit many engineering problems, such as large settlement which occurs in long time after construction. There are a large number of studies carried out to analyze that time dependent behaviour of soft soils, resulting in the variety of theories and models. The mechanism of creep deformation is the background to propose a model for predicting the long term settlement. However, there has been no unique explanation for the behavior of soils, leading to different theories of settlement analysis and prediction. There exist two main hypotheses for settlement calculation, Hypotheses A and B, distinguished based on different elucidation about creep mechanisms. From the existing research studies, this paper aims to discuss five mechanisms of creep including (i) the breakdown of interparticle bonds, (ii) the jumping of bonds of molecules, (iii) sliding movement among particles, (iv) the water drainage in double pore system, and (v) the structural viscosity. In this study, according to the explanation of creep mechanisms, the difference of the two hypotheses will be provided. This paper also suggests a creep mechanism based on the combinations of the explained mechanisms.
Leonard, M, Ball, J & Lambert, M 1970, 'On the coincidence of extreme rainfall bursts with duration', 34th IAHR Congress 2011 - Balance and Uncertainty: Water in a Changing World, Incorporating the 33rd Hydrology and Water Resources Symposium and the 10th Conference on Hydraulics in Water Engineering, Congress of IAHR, the International Association of Hydro-Environment Engineering and Research, Engineers Australia, Brisbane, Australia, pp. 694-701.
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Subdaily, annual maximum rainfall series from a number of locations about Australia are analysed to determine how extreme bursts at one duration coincide with those at another duration. Burst patterns for sites at Darwin and Perth are selected for more detailed investigation. A variety of plots and numerical summaries are presented to show that there is significant structure and overlap between extreme bursts. These observations are relevant to the growing number of models that aim to reproduce the incidence and patterns of extreme bursts. A comparison for one such model, DRIP, is presented as an example of this application.
Li, Y, Li, J & Samali, B 1970, 'Design of new generation magnetorheological pins', Incorporating Sustainable Practice in Mechanics of Structures and Materials - Proceedings of the 21st Australian Conference on the Mechanics of Structures and Materials, Australasian Conference on the Mechanics of Structures and Materials, CRC Press/Balkema, Melbourne, Australia, pp. 807-812.
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Recently, research and development of smart materials and structures for civil engineering applications have attracted increasing attentions from researchers around theworld. Smart devices can be incorporated into civil structures as smart structural members with intelligent and controllable capacities for optimally detecting and reacting to the internal and external changes.Within the smart devices, magnetorheological (MR) based devices are one of the most promising smart devices to be considered for civil structures. This paper presents a novel design of a new-generation MR pin joint with high-torque capacity. An innovative design and analysis of MR pin with radial slots at the surface of the rotary plate is proposed. Theoretical modelling is undertaken based on the material, mechanical and magnetic analyses. Parametric analysis is conducted to optimise the shape, width and depth of the slots to best accommodate the design objectives. © 2011 Taylor & Francis Group, London.
Liaquat, AM, Kalam, MA, Masjuki, HH & Jayed, MH 1970, 'Engine Performance and Emissions Analysis using 'Envo Diesel' and Coconut Biodiesel Blended Fuel as Alternative Fuels', Environmental Science and Technology, Pt 1, 2nd International Conference on Environmental Science and Technology (ICEST 2011), INT ASSOC COMPUTER SCIENCE & INFORMATION TECHNOLOGY PRESS-IACSIT PRESS, Singapore, SINGAPORE, pp. VI168-VI172.
Masjuki, HH, Kalam, MA, Nurul, MF, Jayed, MH, Liaquat, AM & Varman, M 1970, 'Environmentally friendly bio-lubricant lubricity testing', 2011 IEEE Conference on Clean Energy and Technology (CET), 2011 IEEE Conference on Clean Energy and Technology (CET), IEEE.
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Mullard, J & Stewart, M 1970, 'Repair efficiency and Life-Cycle Cost of RC bridge deck maintenance subjected to spatially variable corrosion damage', Applications of Statistics and Probability in Civil Engineering -Proceedings of the 11th International Conference on Applications of Statistics and Probability in Civil Engineering, CRC Press, pp. 2257-2265.
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Corrosion of the reinforcing steel can cause cover cracking and eventual spalling of Reinforced Concrete (RC) surfaces resulting in costly and disruptive repairs. The paper presents a probabilistic reliability analysis which is used to predict the likelihood and extent of corrosion-induced cracking to RC structures. A spatial time-dependent reliability model has been developed where concrete properties, concrete cover and the surface chloride concentrations are treated as random fields. This allows for the calculation of the probability that a given extent of damage will occur for any time period. Three primary maintenance strategies will be considered: i) patch repair, ii) preventative repair, and iii) complete rehabilitative overlay. Incorporated into each of the above maintenance strategies are two repair efficiency factors which take into account varying time to corrosion initiation and corrosion rate of the repair material. These maintenance strategies and repair efficiencies are incorporated in a Monte-Carlo event-based simulation analysis. Results are presented for a RC bridge deck subject to a marine environment. The Life-Cycle Cost analysis considers construction, repair and user delay costs. This predictive capability enables the extent of future repair costs to be more realistically estimated and the optimal maintenance strategies determined © 2011 Taylor & Francis Group, London.
Nazem, M, Kardani, M, Carter, JP & Sheng, D 1970, 'Application of h-adaptive fe method for dynamic analysis of geotechnical problems', Computational Geomechanics, COMGEO II - Proceedings of the 2nd International Symposium on Computational Geomechanics, pp. 490-495.
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h-adaptive finite element procedures automatically change and optimise the density of a finite element mesh in a region to obtain a more accurate solution or to avoid mesh distortion in large deformation problems. These goals are usually achieved by generating a new finite element mesh over the integration domain based upon an error estimation or a distortion criterion. In this study an h-adaptive finite element method is suggested to solve dynamic problems of geomechanics involving large deformations. This hadaptive technique is based upon an implicit Updated-Lagrangian method, in which mesh distortion and entanglement of elements are intrinsic pitfalls. A summary of the h-adaptive technique is presented by introducing its important aspects such as error estimation, remapping of time-dependent state variables, and dynamic equilibrium checks. The efficiency and robustness of the method is demonstrated by considering numerical examples characterised by inertia forces and large deformations.
Nejadi, S & Aslani, F 1970, 'Evaluation and Comparison of the Compressive Stress-Strain Relationships of Self-Compacting Concrete and Conventional Concrete', CONCRETE2011, BUILDING A SUSTAINABLE FUTURE, Concrete Institute of Australia - Biennial Conference, Concrete Institute of Australia, Perth, Western Australia, pp. 1-10.
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Self-compacting concrete (SCC) is considered as a concrete which can be placed and compacted under its own weight with little or no compaction. Whereas it is while being cohesive enough to be handled without segregation or bleeding at the same time. It is used to facilitate and ensure proper filling of the complex and multipart formworks and good structural performance in the heavily reinforced structural members. Modification in the mix design of SCC may have a significant influence on the materialâs mechanical properties. Therefore, it is important to investigate that whether all of the assumed hypotheses for conventional concrete (CC) to design the structures are also valid for SCC construction. The stress-strain curve represents the deformation and strength characteristics and it is an important material behaviour of the concrete. However, due to various influencing factors and the differences between SCC and CC, the proposed curves differ. Hence, it is necessary to study the stress-strain relationship of SCC with its special material composition. This paper reviews the accuracy of the well known stress-strain relationships under uniaxial compression including: Hognestad (8), Smith and Young (9), Desayi and Krishnan (10), Saenz (11), Collins and Mitchell (12) and Mazars and Pijaudier-Cabot (13) that have been developed based on the CC experimental results and are compared with the SCC stress-strain curves experimental results for uniaxial compression available in the literature.
Nghiem, LD, Ren, T, Aziz, N, Porter, I & Regmi, G 1970, 'Treatment of coal seam gas produced water for beneficial use in Australia: A review of best practices', DESALINATION AND WATER TREATMENT, 3rd International Conference on the Challenges in Environmental Science and Engineering (CESE), DESALINATION PUBL, Cairns, AUSTRALIA, pp. 316-323.
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Nicholas, A, Crews, KI & Ariyaratne, W 1970, 'Capacity of Compression Members in RTA Timber Truss Bridges', The Austroads 8th Bridge Conferences - Sustainable Bridges: The Thread of Society - proceedings Volume II, Austroads Bridge Conference, Austroads Incorporated, Sydney, Australia, pp. 268-284.
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Since the introduction of the limit state design method for Australian bridge design in the Austroads Bridge Design Code in 1992, there has not been an associated limit states timber bridge design code. The last applicable code was the working stress design version in the 1976 NAASRA Bridge Design Specification, which invoked AS 1720:1975 SAA Timber Structures Code. The RTA is constantly under pressure to replace or significantly upgrade the remaining timber bridges on NSW roads, because they do not meet current loading standards and because of the large maintenance burden they impose. Many of these bridges employ truss designs that are of heritage significance, and are listed on the State Heritage Register. It has long been recognised that AS 1720 is particularly conservative when it is applied to the design of compression members in RTA timber truss bridges. For this reason, a research and testing program was conducted at UTS in order to develop guidelines to allow reasonable prediction of compression strength of timber members in these bridges. The four primary areas that were studied are bridge timber properties, shear capacity of spacers, creep effects and buckling modes. From this testing, new guidelines have been developed.
Pang, SC, Masjuki, HH, Hazrat, MA & Kalam, MA 1970, 'Integration of 1D and 3D Simulations of Engine Cooling System: After Keyed-Off', 2011 10th International Symposium on Distributed Computing and Applications to Business, Engineering and Science, 2011 Tenth International Symposium on Distributed Computing and Applications to Business, Engineering and Science (DCABES), IEEE.
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Parsa Pajouh, A, Fatahi, B & Khabbaz, H 1970, 'Numerical Back Analysis of Smear Zone Properties for Vertical Drain Assisted Preloading in Soft Soils', ICAGE 2011 - Proceedings of the International Conference on Advances in Geotechnical Engineering, International Conference on Advances in Geotechnical Engineering, Curtin University, Perth, Australia, pp. 561-566.
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Installation of prefabricated vertical drains (PVDs) using a mandrel causes disturbance of the clay surrounding the drain, resulting in a smear zone of reduced permeability, which adversely affects consolidation process. There are two important parameters to characterize the smear effects, namely, the smear zone diameter and the permeability ratio. In this study, FLAC finites difference software has been employed to investigate the effects of smear zone characteristics on required time for preloading. The results of a fully instrumented trial embankment in Sunshine Motorway, Queensland, have been used to verify the model, and parametric studies have been conducted on the predicted ground settlement and pore water pressure. According to the results, changes in smear zone parameters can significantly affect the consolidation period. It is observed that the characteristics of smear zone namely size and permeability have a substantial impact on the preloading design to achieve a certain soil strength and stiffness satisfying both bearing capacity and settlement design criteria.
Ren, XT, Luo, X & Wang, JJ 1970, 'Automatic road clearance surveying with sensor fusion', Proceedings of the 2011 Australasian Conference on Robotics and Automation, Australasian Conference on Robotics and Automation, The Australian Robotics and Automation Association Inc. (ARAA), Monash University, Melbourne Australia, pp. 1-8.
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This paper introduces an automatic road clearance surveying (ARCS) method based on sensor fusion. Equipped with laser measurement system (LMS), camera and proprioceptive sensors (IMU and Odometer), this system is very efficient with improved personal safety. The LMS sensors measure surroundings by collecting range and remission data. Range data is processed to build up 3D model of surveyed objectives with position and attitude information from the proprioceptive sensors. Remission data is used for extracting traffic lanes. The lowest points detected within each lane are considered to be the lanes' clearance, and marked on the 3D model. Experimental results of a vehicle mounted prototype demonstrate its performance for automatic road clearance surveying.
Rujikiatkamjorn, C, Indraratna, B & Aljorany, A 1970, 'Consolidation by vertical drain beneath a circular embankment using analytical and numerical modelling', Computer Methods for Geomechanics: Frontiers and New Applications, pp. 1000-1005.
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When prefabricated vertical drains (PVDs) are installed beneath circular embankment (i.e. circular oil tanks or silos), the system of vertical drains can be replaced by axisymmetric concentric rings with equivalent drain walls. A value for the equivalent coeffi cient of soil permeability must be obtained to provide the same degree of consolidation. A rigorous solution for PVDs installed under circular embankment is proposed and verifi ed by comparing its results with conventional unit cell model. The model is then validated via the consolidation process by vertical drains at the Ska-Edeby circular test embankment (Area II). The calculated values of settlement, lateral displacement and excess pore water pressure provide good agreement with the fi eld measurements.
Saleh, A, Li, J & Lucas, J 1970, 'Internet-hosted assessment system for effective teaching and enhanced learning for engineering subjects', Proceedings of the 22nd Annual Conference for the Australasian Association for Engineering Education (AAEE2011) - Developing Engineers for Social Justice: Community Involvement, Ethics & Sustainability, AAEE - Annual Conference of Australasian Association for Engineering Education, Engineers Australia, Fremantle, WA, pp. 505-509.
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Despite of their popularity, online Learning Management Systems suffer serious limitations as a reliable and effective assessment tool in their implementation for engineering education, partly due to their demand for equation manipulation and multiple stage problem solving. An innovative spreadsheet based assessment tool (e-Task) which is designed to overcome such shortcoming and provides effective teaching and enhanced learning for engineering subjects has been proposed by the authors. The tool was developed for both formative and summative assessments with a capability to automatically collect not only results but also feedback from students on their perceived learning. Building on the previous work, this paper presents a further development by introducing a new deployment concept of the e-Task through internet-hosting of the system in order to enable effective teaching and enhanced learning of engineering subjects. The proposed internet-hosted assessment system (e-Task) integrates state-of-the-art cloud computing technology by incorporating a spreadsheet-like environment that can accommodate a wider range of users and course developers as well as enables easier expansion of the system in the future. It greatly enhances the fundamental concepts proposed in the original e-Taks by offering better accessibility, flexibility and controllability. It obviates any need of a specific software or hardware for the operational platform and requires only Internet access for its operation. Features of the Internet hosted e-Task include: the ability to access it by various Internet browsers, embedding learning and diagnostic feedback, individualised data sets for each students and automated marking & feedback.
Samali, B, Fatahi, B & Tabatabaiefar, HR 1970, 'Seismic behaviour of concrete moment resisting buildings on soft soil considering soil-structure interaction', Incorporating Sustainable Practice in Mechanics of Structures and Materials - Proceedings of the 21st Australian Conference on the Mechanics of Structures and Materials, Australasian Conference on the Mechanics of Structures and Materials, CRC Press/Balkema, Melbourne, Australia, pp. 407-412.
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In this study, the effects of soil-structure interaction (SSI) on the seismic behaviour of reinforced concrete moment resisting building frames are studied using finite difference method. Two types of mid-rise structures, consisting of 5 and 15 stories on soft soil, are selected and analysed. The above mentioned frames are analysed under two different boundary conditions: (i) fixed-base (no soil-structure interaction), and (ii) considering soil-structure interaction. To model soil-structure interaction, the soil medium considering soil's non-linear damping and plasticity with interface elements between soil and structure is included. The results of the analyses in terms of structural forces and lateral displacements for the above mentioned boundary conditions for different earthquakes are compared. It is observed that lateral deflections and drifts of the structures increase when SSI is included. © 2011 Taylor & Francis Group, London.
Samali, B, Li, J, Crews, K & Choi, FC 1970, 'Damage evaluation of a repaired timber beam using modal-based method', Incorporating Sustainable Practice in Mechanics of Structures and Materials - Proceedings of the 21st Australian Conference on the Mechanics of Structures and Materials, Australasian Conference on the Mechanics of Structures and Materials, CRC Press/Balkema, Melbourne, Australia, pp. 751-755.
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For bridge structures, global damage evaluation and structural health monitoring using modal based damage identification methods have dominated recent worldwide research. However, to date there are few works reported on the effectiveness of the methods to evaluate the new conditions after the damaged structures have been repaired. In this paper, a modal based damage identification method for localisation of damage in a timber beam, utilising modal data from before and after damage as well as after repair, is presented based on experimental results. The method employs modal parameters that monitor changes in modal strain energy of damaged and repaired beams with respect to the undamaged one. Experimental modal analysis is used in the experimental work to acquire the modal parameters required by the method. The study aims to investigate the capability and limitations of the proposed method for identifying locations of damage in damaged and repaired timber structures. © 2011 Taylor & Francis Group, London.
Sheng, D & Zhou, AN 1970, 'Hydro-mechanical coupling for unsaturated soils', Unsaturated Soils - Proceedings of the 5th International Conference on Unsaturated Soils, pp. 957-963.
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This paper presents an alternative method to couple the hydraulic component with the mechanical component in a constitutive model for unsaturated soils. Some pioneering work on hydromechanical coupling is first reviewed. Generalised constitutive relations on coupled hydro-mechanical behaviour are then introduced. These generalised constitutive relations are incorporated into an existing model, the SFG model, to predict the effects of specific volume on the saturation-suction relationship. The coupled model is validated against experimental data for different soils. © 2011 Taylor & Francis Group, London.
Shrestha, B, Khabbaz, H & Fatahi, B 1970, 'Experimental Evaluation of Seismic Deformation Characteristics of Vertical-Horizontal Reinforced Soil Walls', ICAGE 2011 - Proceedings of the International Conference on Advances in Geotechnical Engineering, International Conference on Advances in Geotechnical Engineering, Curtin University, Perth, Australia, pp. 797-802.
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Reinforced soils have been widely used in different construction applications including retaining walls. The performance of retaining walls employing vertical reinforcement in conjunction with horizontal reinforcement is investigated experimentally. This paper presents an experimental study of the seismic performance of vertical-horizontal reinforced soil wall on the simulated earthquake using reducedscale shake table tests. Construction of model retaining walls, instrumentation and results from shaking table tests are described in detail. Two types of reinforced walls, conventional horizontal reinforcement and vertical-horizontal reinforcement, were subjected to large shake of the earthquake motions. The geometry of the model, soil properties and reinforcement characteristics has been kept identical in all tests. The reinforcements used were polymeric geogrids, which were connected to the wrap-facing. Each consecutive horizontal reinforcement layers were connected in tension to each other with the help of vertical connections. The walls were instrumented using transducers to measure wall facing displacement, and accelerations within the soil. The magnitude of lateral displacement under base excitation significantly reduced when vertical reinforcement was included to the wall system.
Shrestha, B, Khabbaz, H & Fatahi, B 1970, 'PERFORMANCE ANALYSIS OF REINFORCED SOIL FOUNDATION STRUCTURES WITH VERTICAL REINFORCEMENT', GEOTECHNICAL ENGINEERING FOR DISASTER MITIGATION AND REHABILITATION 2011/GEOTECHNICAL AND HIGHWAY ENGINEERING - PRACTICAL APPLICATIONS, CHALLENGES AND OPPORTUNITIES, 3rd Int Conf on Geotechnical Engn for Disaster Mitigation and Rehabilitation/5th Int Conf on Geotechnical and Highway Engn - Practical Applications, Challenges and Opportunities, WORLD SCIENTIFIC PUBL CO PTE LTD, Semarang, INDONESIA, pp. 443-448.
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This study examines the performance of geosynthetic reinforced wall inserting vertical elements in conjunction with conventional horizontal reinforcements. In this system, similar to normal reinforcement, the selected granular material is compacted over the horizontal reinforcement up to the designed height and then another layer of horizontal reinforcement is laid down. Numerical investigations have been carried out using finite element software, PLAXIS. Geosynthetic reinforced soil foundation performance and its characteristics have been simulated with and without vertical reinforcement under static and dynamic loads. Numerical results show that the total settlement decreases by inserting inclined reinforcement in both static and dynamic loading in general, and particularly under seismic loading. A new bearing capacity formula incorporating the contribution of both vertical and horizontal reinforcements is also introduced based on the previously published studies and the outputs of this numerical simulation.
Shrestha, B, Khabbaz, H & Fatahi, B 1970, 'Performance Comparison of Vertical-Horizontal with Conventional Reinforced Soil Walls Using Numerical Modelling', PROCEEDINGS OF THE 15TH AFRICAN REGIONAL CONFERENCE ON SOIL MECHANICS AND GEOTECHNICAL ENGINEERING: RESOURCE AND INFRASTRUCTURE GEOTECHNICS IN AFRICA: PUTTING THEORY INTO PRACTICE, 15th African Regional Conference on Soil Mechanics and Geotechnical Engineering (ARCSMGE), IOS PRESS, Maputo, MOZAMBIQUE, pp. 237-242.
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Conventional reinforced soil walls have demonstrated acceptable performance during earthquake occurrences. Nevertheless, there is still some potential for enhancing the performance of these walls without increasing the cost significantly. This paper presents an overview on the application of vertical components to the reinforced soil in addition to the horizontal reinforcement. The performance of conventional and the modified reinforced soil walls are evaluated and compared to each other. In this study, a series of 2D models is carried out using PLAXTS, finite element software, to investigate behaviour of these walls. The performance of reinforced walls is evaluated under the seismic loads of Kobe earthquake. The results indicate that the proposed wall with vertical reinforcement has superior performance compared with the conventional method and can reduce the risk of failure during earthquakes.
Sleap, SB, Turner, BD & Sloan, SW 1970, 'Fluoride remediation with calcite as a function CO2 partial pressure', Computer Methods for Geomechanics: Frontiers and New Applications, pp. 751-756.
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At Hydro Aluminium located in the Hunter Valley, NSW, Australia, spent potliner (SPL) waste has contaminated the local ground water aquifer with concentrations of fl uoride up to 2,000 mg/L. The ability of calcite (CaCO 3) to remove this fl uoride was studied in a batch reactor as a function of CO2 partial pressure and fraction size. Results show that fl uoride removal at equilibrium is independent of fraction size, but the rate at which equilibrium is achieved is faster for smaller sized fractions (larger surface area). The optimum partial pressure of CO2 was between 7% and 15% with ~95% & 98% F removal achieved respectively in experiments using pure fl uoride solutions. Results using actual SPL contaminated groundwater indicate removal by calcite is dependent on at least two different chemical pathways (mechanisms) that can adversely affect defl uoridation and that geochemical models require rigorously defi ned kinetic data before they can be used to accurately predict results in this system.
Sloan, SW, Abbo, AJ & Sheng, DC 1970, 'Accelerated convergence of Newton-Raphson method using a least squares approximation to the consistent tangent matrix', Computer Methods for Geomechanics: Frontiers and New Applications, pp. 15-20.
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Consistent tangent formulations have the highly desirable property of providing quadratic convergence when Newton-Raphson iteration is used to solve the global stiffness equations. The implementation of these formulations, however, is not straightforward as they require the use of an implicit stress integration scheme in order to form the consistent stiffness matrix. These integration schemes are not well suited to adaptive sub-stepping (which is extremely effective for handling the complex constitutive relations that are typical for geomaterials) and are prone to non-convergence unless very small load steps are used. This paper presents a new technique for accelerating the convergence of Newton-Raphson iteration that is based on the consistent tangent approach with a least squares approximation to the plastic multiplier. The signifi cance of the method is that it allows a quasi-consistent tangent formulation to be used in conjunction with explicit stress integration schemes. Although the procedure does not provide quadratic convergence, it does accelerate the Newton-Raphson iteration process dramatically and is very robust.
Sofi, M, Mendis, P, Baweja, D & Elvira, E 1970, 'Bond performance of strand and wire in early age concrete', Proceedings of the 9th International Symposium on High Performance Concrete - Design, Verification & Utilization (TR48), International Symposium on High Performance Concrete, New Zealand Concrete Society (NZCS), Rotorua, NZ, pp. 1-10.
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Many failures have occurred in the live and dead end anchors of post-tensioned (PT) suspended slabs during the post-tensioning process, prompting a closer study of the behaviour of anchorage zone concrete. In suspended slabs, the post-tensioning loads are transferred to concrete mass via an anchorage assembly that consists in a strand and anchor component. As a part of wider study to establish the failure mechanism of anchorage zone concrete, pullout tests are carried out to investigate the bond behaviour of the strand and wire in early age concrete. Direct type pullout specimens were tested at 3, 4, 7, 14 and 21 days after pouring the concrete. The aim of the experiments was to evaluate the bond performance of strand and wire in high early strength concrete. Selected experimental results and a finite element model representing the pullout tests are presented in this paper. The model is validated based on the load-displacement results. Relevant parameters are discussed.
Sofi, M, Mendis, PA, Baweja, D & Elvira, E 1970, 'Anchorage zones behaviour of early age concrete: Application to post-tensioned members', Incorporating Sustainable Practice in Mechanics of Structures and Materials - Proceedings of the 21st Australian Conference on the Mechanics of Structures and Materials, Australasian Conference on the Mechanics of Structures and Materials, pp. 261-266.
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Anchorage zones of post-tensioned (PT) concrete slabs experience concentrated stresses as a result of post-tensioning procedures during the construction. The PT load is applied at two different stages after casting the concrete. This is to prevent shrinkage cracks and to overcome pre-stressing losses. During the early ages, however, concrete undergoes exothermic hydration reaction resulting in volume changes and associated thermal and time-dependent strains. During this time, if the strength development is lagging behind the induced stresses, severe micro-cracking can result. This can be a precursor to anchorage zone failures. To illustrate the case, Finite Element simulation of a rectangular section anchorage specimen is presented. The model consists in two distinct phases: the first phase simulates the hydration and associated thermal effects, and the second phase discusses the mechanical load imposed while the concrete hydration is ongoing. © 2011 Taylor & Francis Group, London.
Sofi, M, Zhang, L, Mendis, PA & Baweja, D 1970, 'Early age concrete creep: Using model B3 prediction', Incorporating Sustainable Practice in Mechanics of Structures and Materials - Proceedings of the 21st Australian Conference on the Mechanics of Structures and Materials, Australasian Conference on the Mechanics of Structures and Materials, pp. 267-272.
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Thermal and visco-elastic effects are more pronounced in early age concrete (1 to 7 days). This is due to the presence of free water and un-hydrated cementious particles. It is common practice to load the structural members during this time in order to meet the tight construction schedule. As a result, regions of high stress concentrations, such as anchorage zones in post-tensioned (PT) members, experience higher time dependent strains. This paper discusses the early age concrete effects and the predictions of early age creep strains using B3 model. A simple cylindrical specimen is considered for the analysis. © 2011 Taylor & Francis Group, London.
Stewart, M, Wang, X & Nguyen, M 1970, 'Deterioration of concrete structures in Australia under changing environment', Applications of Statistics and Probability in Civil Engineering -Proceedings of the 11th International Conference on Applications of Statistics and Probability in Civil Engineering, CRC Press, pp. 2085-2093.
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Atmospheric CO2 is a major cause of reinforcement corrosion in bridges, buildings, wharves, and other concrete infrastructure. The increase in CO2 levels associated with global warming will increase the likelihood of carbonation-induced corrosion. Moreover, temperature rises will increase corrosion rates. Clearly, the impact of climate change on existing and new infrastructure is considerable, as corrosion damage is disruptive to society and costly to repair. The paper describes a probabilistic and reliability-based approach that predicts the probability of corrosion initiation and damage (severe cracking) for concrete infrastructure subjected to carbonation and chloride-induced corrosion resulting from elevated CO2 levels and temperatures. The atmospheric CO2 concentration and local temperature and relative humidity changes with time over the next 100 years in Australian cities are projected based on nine General Circulation Models (GCMs) under A1B, A1FI and 550 ppm stabilisation CO2 emission scenarios. The probabilistic analysis included the uncertainty of CO2 concentration, deterioration processes, material properties, dimensions, and predictive models. It was found that carbonation-induced damage risks can increase by over 400% over a time period to 2100 for some regions in Australia. Damage risks for chloride-induced corrosion increase by no more than 15% over the same time period due to temperature increase. Corrosion loss of reinforcement is not significant © 2011 Taylor & Francis Group, London.
Stewart, MG & Wang, X 1970, 'Risk assessment and economic viability of climate adaptation measures for Australian housing subject to extreme wind events', MODSIM 2011 - 19th International Congress on Modelling and Simulation - Sustaining Our Future: Understanding and Living with Uncertainty, pp. 2852-2858.
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Australia is a continent subject to climatic extremes, and its losses from tropical cyclones and thunderstorms are significantly higher than other natural hazards. The number of severe tropical cyclones is likely to increase due to climate change. Brisbane and the northeast coast of Queensland are regions where design wind specifications may be inadequate under future climate conditions. For example, the Australia Building Codes Board is considering a shift in the boundary to cyclone Region C to extend it south on the Queensland coast to 27°S to include areas in the Sunshine Coast. Hence, there is an urgent need to assess the risks and economic viability of these climate adaptation measures. An appropriate adaptation strategy may be one that increases design wind speeds for new houses leading to reduced vulnerability of new construction. The present paper will assess the damage risks, adaptation costs and cost-effectiveness of this adaptation measure for residential construction in the Queensland cities of Cairns, Townsville, Rockhampton and Brisbane assuming time-dependent changes in frequency and intensity of cyclonic and non-cyclonic winds to 2100. Advanced spatial and temporal stochastic simulation methods will be used to include uncertainty and variability of climate and building vulnerability on damage risks. The criteria for cost-effectiveness are reduction in present value measured by Net Present Value (NPV) and probability that NPV exceeds zero. The simulation analysis found that increasing the wind classification for design of new housing (at a cost of $3,700 per house) for all cities can produce a mean NPV that exceeds $8.3 billion by 2100 assuming a 4% discount rate (see Figure 1). The benefits are highest for Brisbane due to its high exposure (large population) and relatively high vulnerability of existing residential construction. Retrofitting older houses is a more costly adaptation strategy which mostly resulted in a net loss. We also showed that ...
Su, LJ, Indraratna, B & Rujikiatkamjorn, C 1970, 'Non-destructive assessment of rail track condition using ground penetrating radar', Computer Methods for Geomechanics: Frontiers and New Applications, pp. 478-482.
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Ground penetrating radar (GPR) can be used to locate interfaces and underground utilities, and evaluate ballast fouling conditions, moisture content and subgrade conditions depending on frequencies of antenna and data processing techniques. In Australia, trial testing on railway sections has been conducted by the railway industry. However, in these trials, testing is only conducted on actual tracks where the relationship between track conditions and the GPR response has not yet been established. In this paper, a full scale model rail track designed and constructed at the University of Wollongong is used to investigate factors that infl uence the GPR data quality, such as the GPR antenna frequency, the degree and moisture content of ballast fouling and sampling frequency. GPR testing was conducted using ground coupled antennas with different frequencies. Comparisons are made to identify the suitable frequency applicable for the assessment of track condition which will be used subsequently to improve the accuracy of site investigations.
Thakur, PK, Vinod, JS & Indraratna, B 1970, 'The role of particle breakage on the shear behaviour of coarse granular materials: A micromechanical investigation', Geomechanics and Geotechnics: From Micro to Macro - Proceedings of the International Symposium on Geomechanics and Geotechnics: From Micro to Macro, IS-Shanghai 2010, International Symposium on Geomechanics and Geotechnics - From Micro to Macro, CRC PRESS-TAYLOR & FRANCIS GROUP, Shanghai, PEOPLES R CHINA, pp. 585-589.
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In this investigation, a DEM based computer program Particle Flow Code in Two Dimension (PFC 2D) has been used to study the cyclic behavior of ballast particles. Angular ballast particles were modeled as clusters of bonded circular particles and degradation of the bonds within a cluster was considered to represent particle breakage. The results of DEM simulations captured the ballast behaviour under cyclic loading in accordance with the experimental observations. Furthermore, a relationship has been proposed between, micromechanical parameter, particle displacement vectors and number of bond breakage. © 2011 Taylor & Francis Group.
Yang, C, Sheng, DC & Carter, JP 1970, 'Numerical modelling of hydraulic hysteresis in unsaturated soil covers', Computer Methods for Geomechanics: Frontiers and New Applications, pp. 741-746.
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This paper aims to study the effect of hydraulic hysteresis on seepage in unsaturated soils. A hysteretic water retention model is incorporated into the Richards equation to describe water fl ow in unsaturated soils. A linear scanning curve is used to describe the hydraulic behaviour within the main hysteretic loop of the water retention curves. The proposed approach is implemented into a fi nite difference code, and is then used to analyse seepage in soil covers on wastes. An infi ltration test on a two-layered soil column is simulated with the proposed hysteretic model. Results show that hydraulic hysteresis plays a crucial role in the seepage analysis of unsaturated soils subjected to cyclic drying and wetting. The hysteretic model is suggested for use in the design and evaluation of the hydraulic performance of soil covers.
Yang, L, Thomas, P & Stuart, BH 1970, 'DSC characterisation of thermally treated low density polyethylenes in a forensic context', Proceedings of the 3rd Joint Czech-Hungarian-Polish-Slovak Thermoanalytical Conference, Slovak Chemical Society, Stara Lesna, pp. 1-5.
Zhang, RJ, Yang, HL, L’Hostis, V, Castel, A & François, R 1970, 'Characterization of Steel/Concrete Interface for a Long-Term Corroded Beam Stored in Chloride Environment', Advanced Materials Research, International Conference on Structures and Building Materials, Trans Tech Publications, Ltd., Guangzhou, PEOPLES R CHINA, pp. 3415-3420.
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This paper deals with the steel/concrete interface of a corroded beam B2CL1 after a 23 years exposure in chloride environment. XRD, SEM and Raman techniques were performed to investigate the chemical compositions and the spatial distribution of corrosion products. The experimental results illustrate that the corrosion product layer is a multi-layer constituted as marbling structure. It is composed of a mix of iron oxides and iron oxi-hydroxides. Iron species were found in the vicinity of concrete mainly in cracks, as it was already observed in the literature.
Zhu, X, Uy, B, Mirza, O & Hao, H 1970, 'Condition Assessment of Composite Structures using Dynamic Measurements', DYNAMICS FOR SUSTAINABLE ENGINEERING, VOL 1, 14th Asia Pacific Vibration Conference (APVC) on Dynamics for Sustainable Engineering, HONG KONG POLYTECHNIC UNIV, Hong Kong, PEOPLES R CHINA, pp. 307-316.
Zhu, XQ, Cao, DQ, Law, SS & Pan, JZ 1970, 'Nonlinear Behaviour of Damaged Concrete Bridge Structures under Moving Vehicular Loads', DYNAMICS FOR SUSTAINABLE ENGINEERING, VOL 1, 14th Asia Pacific Vibration Conference (APVC) on Dynamics for Sustainable Engineering, HONG KONG POLYTECHNIC UNIV, Hong Kong, PEOPLES R CHINA, pp. 242-251.