Brown, LD, Ray, AS & Thomas, PS 2004, 'Elemental analysis of Australian amorphous banded opals by laser-ablation ICP-MS', NEUES JAHRBUCH FUR MINERALOGIE-MONATSHEFTE, vol. 9, no. 9, pp. 411-424.
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Brown, LD, Ray, AS & Thomas, PS 2004, 'Elemental analysis of Australian amorphous banded opals by laser-ablation ICP-MS', Neues Jahrbuch fur Mineralogie, Monatshefte, no. 9, pp. 411-424.
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Several banded Australian opal-AG samples were analysed by laser ablation ICP-MS. The banded opals studied contained darker-coloured black or grey bands adjacent to lighter-coloured white or clear bands. The elemental distribution between bands indicated that darker-coloured bands contained significantly higher concentrations of transition elements (Ti, Co, V, Ni, Cu, Zn and Y) and rare-earth elements (La, Ce) than lighter-coloured bands. A solution depletion model, involving the charge-neutralisation of silica collóids by highly-charged transition metal cations, is proposed to explain these results. Irrespective of the origin of the opal, the distribution of trace elements for the white, translucent and play of colour opal bands was observed to be similar. This similarity was consistent with the proposed model. © 2004 E. Schweizerbart'sche Verlagsbuchhandlung, D-70176 Stuttgart.
Ding, G & Langston, C 2004, 'Multiple Criteria Sustainability Modelling: Case Study on School Buildings', International Journal of Construction Management, vol. 4, no. 2, pp. 13-26.
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Epaarachchi, DC & Stewart, MG 2004, 'Human Error and Reliability of Multistory Reinforced-Concrete Building Construction', Journal of Performance of Constructed Facilities, vol. 18, no. 1, pp. 12-20.
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This paper develops probabilistic and human reliability models to estimate the probability of structural collapse (system risk) during the construction of typical multistory reinforced-concrete buildings in the presence of human error. Results obtained from the human reliability analysis suggest that errors related to concrete cover and concreting workmanship are more detrimental to system risk than any other errors. Errors related to reinforcement area have a minor effect on system risk, provided that the existing effectiveness of engineering inspections is maintained. The results also show that errors related to installation of steel shores/reshores do not significantly affect the system risk.
GATIDOU, G, ZHOU, J & THOMAIDIS, N 2004, 'Microwave-assisted extraction of Irgarol 1051 and its main degradation product from marine sediments using water as the extractant followed by gas chromatography–mass spectrometry determination', Journal of Chromatography A, vol. 1046, no. 1-2, pp. 41-48.
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A microwave-assisted extraction (MAE) method for the determination of Irgarol 1051 (2-methylthio-4-tert-butylamino-6-cyclopropylamino-s-triazine) and its main degradation product M1 (2-methylthio-4-tert-butylamino-s-triazine) in marine sediments by gas chromatography-mass spectrometry (GC-MS) was developed. The key parameters of MAE procedure, including the amount of the sediment, the volume of the extraction solvent, the duration and the temperature of the extraction procedure were optimized. The extraction procedure was followed by solid-phase extraction (SPE) on reverse phase C 18 cartridges. The isolation of the target compounds from the matrix was found to be efficient when 3 g of marine sediment were extracted with 30 ml of water for 10 min at 115°C. Final determination was accomplished by GC-MS. Quantification was performed with matrix-matched calibration using atrazine-d 5 as internal standard. Mean recoveries higher than 85.4% were obtained for both compounds at three fortification levels with relative standard deviations (R.S.D.) ≤ 14%. The limits of detection (LOD) of the developed method were 0.9 and 1.7 ng g -1 dry weight for M1 and Irgarol 1051, respectively. © 2004 Elsevier B.V. All rights reserved.
Gatidou, G, Zhou, JL & Thomaidis, NS 2004, 'Microwave-assisted extraction of Irgarol 1051 and its main degradation product from marine sediments using water as the extractant followed by gas chromatography–mass spectrometry determination', Journal of Chromatography A, vol. 1046, no. 1-2, pp. 41-48.
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Glamore, W & Indraratna, B 2004, 'A two-stage decision support tool for restoring tidal flows to flood mitigation drains affected by acid sulfate soil: Case study of Broughton Creek floodplain, New South Wales, Australia', Australian Journal of Soil Research, vol. 42, no. 5-6, pp. 639-648.
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A 2-stage flood estimation and water quality decision support tool (DST) was developed, calibrated, and applied to a field site in south-eastern New South Wales (NSW) to simulate tidal restoration in a flood mitigation drain affected by acid sulfate soils leachate. The first stage of the DST employs a digital terrain map, geographic information tools, and measured water levels to calculate drain water overtopping due to tidal variations. Simulations using the GIS technique at the study site indicated that the primary drainage network can safely contain full tidal flushing (0.91 m AHD or a 58% increase), whereas at the same level the secondary drainage network overtops along relict drainage channels. The second stage of the DST simulates the change in drain water quality using an ion-specific program code written within the open interface PHREEQC program. The results from the water quality model were calibrated against laboratory titration tests. Drain water pH was shown to increase above 6.0, and soluble aluminium and iron concentrations decreased by 73% and 56%, respectively. The extent of water quality change is directly related to the ionic strength of the intruding water and the ion-specific reaction kinetics of aluminium, iron, and sulfate. Based on the DST simulations, floodgate modifications to restore tidal flushing were successfully undertaken at a study site near Berry, in south-eastern NSW. DST predictions accurately simulated field results (±10%) and slight variations between data were attributed to the prolonged drought at the field site, which increased the ionic strength of intruding waters, and the high concentration of sulfate in seawater. The DST can be easily adapted to other sites throughout Australia.
Guo, WS, Vigneswaran, S, Ngo, HH & Chapman, H 2004, 'Experimental investigation of adsorption-flocculation-microfiltration hybrid system in wastewater reuse', JOURNAL OF MEMBRANE SCIENCE, vol. 242, no. 1-2, pp. 27-35.
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Membrane hybrid systems are becoming increasingly important as cost effective solutions in wastewater treatment and reuse. The effect of pretreatments namely floating medium flocculation (FMF) and powdered activated carbon (PAC) adsorption on organic and phosphorus removal was studied. The FMF was found to increase the phosphorus removal up to 97%. This preflocculation improved the dissolved organic removal only marginally (from 20% to 40%) whilst the pretreatment of adsorption increased the organic removal to more than 98%. The decline in filtration (permeate) flux of microfiltration was reduced by the incorporation of these pretreatment methods. Detailed studies on the effect of PAC dose indicated that a PAC dose of 1 g/L was the optimum in terms of organic removal and filtration flux. PAC doses in excess of 1 g/L contributed to a significant decrease in filtration flux. The critical flux was experimentally evaluated for crossflow microfiltration (CFMF) with and without the pretreatment. The pretreatment of adsorption led to six times higher critical flux than that without any pretreatment. The preflocculation alone did not significantly increase the critical flux. There was only a 33% increase with preflocculation. However, the preflocculation combined with PAC adsorption resulted in nine times higher critical flux. The results showed that a pretreatment of flocculation and adsorption led to almost complete phosphorus and organic removal while reducing the membrane clogging. © 2004 Elsevier B.V. All rights reserved.
Hoang, TTL, Shon, HK, Chaudhary, DS, Vigneswaran, S & Ngo, HH 2004, 'Granular Activated Carbon (GAC) biofilter for low strength wastewater treatment', Fluid - Particle Separations Journal, vol. 16, no. 2, pp. 185-191.
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Biofilter can be a cost-effective alternative treatment unit, especially for low strength wastewater. In this study, detailed experimental investigation of a GAC biofilter was carried out in a laboratory-scale unit using low strength synthetic wastewater and biologically treated sewage effluent (BTSE). Performance of the biofilter was evaluated in terms of total organic carbon (TOC) removal. The TOC removal efficiency of the biofilter was found to be stabilized at around 40-45 % after 30 days (even for a short depth of GAC column of 7-15 cm). The maximum biomass retained on the activated carbon was measured to be 44 mg/ g of GAC after 49 days of continuous operation. Filter backwashing provided at 30% bed expansion for 5 minutes on a daily basis to overcome physical clogging of the filter by attached mass, did not have any adverse effect on the active biomass attached to the media and thus the organic removal efficiency of the filter remained unchanged. Molecular size distribution analysis showed that a significant removal of organics of small molecular weight (MW) at the initial stage of operation of biofilter followed by mainly large MW organic matter after one day of operation. This shows that adsorption was the main mechanism at the initial period and biological degradation as the predominating mechanism after one day of operation throughout the rest of the operation. The biofilter was found to remove a majority of hydrophilic organic compounds.
Huang, Z, Sun, X, Xiu, Z, Chen, S & Tsai, C-T 2004, 'Precipitation synthesis and sintering of yttria nanopowders', Materials Letters, vol. 58, no. 15, pp. 2137-2142.
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Indraratna, B, Bamunawita, C & Khabbaz, H 2004, 'Numerical modeling of vacuum preloading and field applications', CANADIAN GEOTECHNICAL JOURNAL, vol. 41, no. 6, pp. 1098-1110.
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This study describes the effect of unsaturation at a drain boundary on the behaviour of a single prefabricated vertical drain subjected to vacuum preloading based on a two-dimensional plane strain finite element model incorporating the modified Cam-Clay model. Unsaturation of soil adjacent to the drain can occur due to mandrel withdrawal or application of vacuum pressure through prefabricated vertical band drains (PVDs). Following initial laboratory simulation in a large-scale radial drainage consolidometer, the authors have attempted to explain the observed retardation of pore pressure dissipation through a series of models, which consider the effect of unsaturation at the drain-soil interface. The results indicate that the introduction of an unsaturated soil layer adjacent to a PVD improves the accuracy of numerical predictions. Lastly, a multidrain analysis is conducted to study the behaviour of an embankment stabilized with vertical drains subjected to vacuum preloading, and the field measurements are compared with a series of numerical model predictions.
Kalam, MA & Masjuki, HH 2004, 'Emissions and deposit characteristics of a small diesel engine when operated on preheated crude palm oil', Biomass and Bioenergy, vol. 27, no. 3, pp. 289-297.
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Khatri, RP, Sirivivatnanon, V & Heeley, P 2004, 'Critical polarization resistance in service life determination', CEMENT AND CONCRETE RESEARCH, vol. 34, no. 5, pp. 829-837.
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King, AJ, Readman, JW & Zhou, JL 2004, 'Determination of polycyclic aromatic hydrocarbons in water by solid-phase microextraction–gas chromatography–mass spectrometry', Analytica Chimica Acta, vol. 523, no. 2, pp. 259-267.
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A solid-phase microextraction (SPME)-gas chromatography (GC)-mass spectrometry (MS) analytical method for the simultaneous separation and determination of 16 polycyclic aromatic hydrocarbons (PAHs) from aqueous samples has been developed, based on the sorption of target analytes on a selectively sorptive fibre and subsequent desorption of analytes directly into GC-MS. The influence of various parameters on PAH extraction efficiency by SPME was thoroughly studied. Results show that the fibre exposure time and the use of agitation during exposure are critical in enhancing SPME performance. The presence of colloidal organic matter (as simulated by humic acid) in water samples is shown to significantly reduce the extraction efficiency, suggesting that SPME primarily extracts the truly dissolved compounds. This offers the significant advantage of allowing the differentiation between freely available dissolved compounds and those associated with humic material and potentially biologically unavailable. The method showed good linearity up to 10 μg/l. The reproducibility of the measurements expressed as relative standard deviation (R.S.D.) was generally <20%. The method developed was then applied to extract PAHs from sediment porewater samples collected from the Mersey Estuary, UK. Total PAH concentrations in porewater were found to vary between 95 and 742 ng/l with two to four ring PAHs predominating. Results suggest that SPME has the potential to accurately determine the dissolved concentrations of PAHs in sediment porewater. © 2004 Elsevier B.V. All rights reserved.
King, AJ, Readman, JW & Zhou, JL 2004, 'Dynamic behaviour of polycyclic aromatic hydrocarbons in Brighton marina, UK', Marine Pollution Bulletin, vol. 48, no. 3-4, pp. 229-239.
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The distribution of polycyclic aromatic hydrocarbons (PAHs) between various phases is fundamental in the control of their movement and impact in the marine environment. In this study samples of water and sediments were regularly collected from Brighton marina, UK, to quantify the intensity, spatial and temporal variations of PAH contamination. The results show clearly that PAH behaviour in marine systems is highly complex, and controlled by the interplay of PAH sources, compound physicochemical properties, water and sediment movement, and field conditions. Levels of total PAHs (16 compounds) in the dissolved phase were found to vary between <2 and 11,400 ng/l, with higher values observed in the winter months. Total PAH concentration in sediment samples varied between 24 and 4710 ng/g dry weight. PAHs in water were dominated by low molecular mass compounds (2-ring), while PAHs in sediments were mainly derived from 2-4 ring compounds. In addition, dissolved concentrations were increased during sediment dredging and after a period of severe rainfall. PAHs in Brighton marina are likely to be from both pyrolytic and petrogenic sources; as a result, field-derived distribution coefficients for individual PAHs between sediment and water tend to follow the equilibrium partition models, although slight exceedance is apparent. The extended partition model incorporating soot carbon has achieved limited success in better predicting PAH behaviour. © 2003 Elsevier Ltd. All rights reserved.
Law, SS & Zhu, XQ 2004, 'Dynamic behavior of damaged concrete bridge structures under moving vehicular loads', Engineering Structures, vol. 26, no. 9, pp. 1279-1293.
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Law, SS, Bu, JQ, Zhu, XQ & Chan, SL 2004, 'Vehicle axle loads identification using finite element method', Engineering Structures, vol. 26, no. 8, pp. 1143-1153.
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Lee, HK, Hewitson, S & Wang, J 2004, 'Web-based resources on GPS/INS integration', GPS Solutions, vol. 8, no. 3, pp. 189-191.
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The integrated GPS/INS system has become an indispensable tool for providing precise and continuous position, velocity and attitude information for many positioning and navigation applications, from surveying and mapping to vehicle navigation, guidance and control. There is an extensive variety of websites that are directly or indirectly related to the technologies and applications of GPS/INS integration. This column presents a selection of the publicly available web-based resources on research-based activities for GPS/INS integration. The selection encompasses those international universities and companies that provide electronic versions of their publications.
Li, J, Samali, B & Crews, K 2004, 'Determining individual member stiffness of bridge structures using a simple dynamic procedure', Acoustics Australia, vol. 32, no. 1, pp. 9-12.
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A reliable determination of the structural condition of timber bridges presently requires costly load testing. A new dynamic based testing method was developed by authors to reduce the cost and shorten the testing time. The method has been successfully used to undertake field-testing of more than 40 timber bridges across NSW. The dynamic testing procedure involves the attachment of accelerometers underneath the bridge girders. The bridge girders are then excited by a modal hammer. The method requires tests with and without extra mass, so that the overall flexural stiffness of the bridge can be obtained. However, in order to accurately estimate the load carrying capacity of the bridge, it is necessary to obtain the stiffness values of individual members from test results without complicating the current testing procedure. In this paper, the authors review the dynamic testing procedure and propose a method to determine individual member stiffness for a bridge structure based on the field dynamic testing data. The outcomes of this work not only enable more accurate prediction of the load carrying capacity of the bridge but will also identify defective members of the bridge structure.
Liu, B, Thomas, PS, Klimesch, DS & Ray, A 2004, 'Fourier transform infrared evaluation of autoclaved cellulose fibre pulps used in cement-based building materials', ADVANCES IN CEMENT RESEARCH, vol. 16, no. 4, pp. 131-136.
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Liu, B, Thomas, PS, Klimesch, DS & Ray, A 2004, 'Fourier transform infrared evaluation of autoclaved cellulose fibre pulps used in cement-based building materials', Advances in Cement Research, vol. 16, no. 4, pp. 131-136.
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Liu, B, Thomas, PS, Ray, AS & Williams, RP 2004, 'The effect of sampling conditions on the thermal decomposition of electrolytic manganese dioxide', JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY, vol. 76, no. 1, pp. 115-122.
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The effect of sampling conditions on the decomposition of electrolytic manganese dioxide using thermal methods is reported. Significant differences were observed in the mechanism of the decomposition by simply changing the reaction environment from a closed pan to an open pan configuration. The purge gas atmosphere was also observed to influence the decomposition mechanism. As a product of the decomposition is oxygen, the change in the mechanism observed between the experimental conditions may be explained in terms of the ease of removal of oxygen from the reaction site.
Liu, Q, Loganathan, P, Hedley, MJ & Skinner, MF 2004, 'The mobilisation and fate of soil and rock phosphate in the rhizosphere of ectomycorrhizal Pinus radiata seedlings in an Allophanic soil', PLANT AND SOIL, vol. 264, no. 1-2, pp. 219-229.
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Phosphorus (P) characteristics and the fate of a finely divided Sechura phosphate rock (SPR) applied to a P deficient Allophanic Soil (Andosol) were investigated in the rhizosphere of 1-year-old Pinus radiata seedlings grown for 10 months in pots. The rates of SPR (13.9% P) application were 0, 50, 100 and 150 μg P g-1 soil. Increased rate of application of SPR increased seedling growth and P uptake by P. radiata, but SPR rates had no consistent effect on mycorrhizal tip density. The highest mycorrhizal tip density (tips per metre root) was observed at the P rate of 50 μg P g-1 soil. Increased seedling growth with increased SPR rates was due to increased SPR dissolution. The SPR dissolution at plant harvest was high (> 80%) but was significantly higher in the rhizosphere soil than in the bulk soil, probably due to increased soil acidification and oxalate production in the rhizosphere. The seedling roots induced significantly higher acid and alkaline phosphatase activities in the rhizosphere soil. This was associated with significant decreases in the concentration of labile organic P (0.1 M NaOH-Po) in the rhizosphere soil. Rhizosphere acidification and decrease in 0.1 M NaOH-Po resulted in accumulation of 0.1 M NaOH extractable inorganic P in the rhizosphere soil, but no difference was recorded in resin-P concentration between the rhizosphere and bulk soils. These results suggest that mycorrhizal root-induced conversion of organic P to inorganic P is a major process of P supply to P. radiata seedlings in P deficient Allophanic Soils. © 2004 Kluwer Academic Publishers.
Liu, R, Zhou, JL & Wilding, A 2004, 'Microwave-assisted extraction followed by gas chromatography–mass spectrometry for the determination of endocrine disrupting chemicals in river sediments', Journal of Chromatography A, vol. 1038, no. 1-2, pp. 19-26.
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In this study, microwave-assisted extraction (MAE) followed by gas chromatography (GC)-mass spectrometry (MS) analysis has been successfully developed for the simultaneous extraction and determination of contrasting endocrine disrupting chemicals (EDCs) including 17β-estradiol, estrone, 17α-ethynylestradiol, 16α-hydroxyestrone, 4-nonylphenol, 4-tert-octylphenol and bisphenol A in river sediments. For MAE, the effects of various parameters on the extraction efficiency were investigated. It is shown that the most efficient extraction (recovery >74%) of the target compounds was achieved by using methanol as the solvent, an extraction temperature of 110°C and 15 min of holding time. The cleanup of extracts was carried out by passage through a non-deactivated silica gel column, and a satisfactory elution efficiency of all compounds was achieved using a solvent mixture of ethyl acetate-hexane (4:6, v/v). The spiking experiments show that the mean recovery of the target compounds exceeded 61% at a spiking level of 5 ng/g dry mass, and 73% at 10, 40 and 100 ng/g dry mass with a good reproducibility. The method developed was applied to the determination of target EDCs in river sediments collected from rivers Uck and Ouse, UK, and results revealed the presence of the chosen compounds at low ng/g level. © 2004 Elsevier B.V. All rights reserved.
Liu, R, Zhou, JL & Wilding, A 2004, 'Simultaneous determination of endocrine disrupting phenolic compounds and steroids in water by solid-phase extraction-gas chromatography-mass spectrometry', JOURNAL OF CHROMATOGRAPHY A, vol. 1022, no. 1-2, pp. 179-189.
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Liu, R, Zhou, JL & Wilding, A 2004, 'Simultaneous determination of endocrine disrupting phenolic compounds and steroids in water by solid-phase extraction–gas chromatography–mass spectrometry', Journal of Chromatography A, vol. 1022, no. 1-2, pp. 179-189.
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A solid-phase extraction (SPE)-gas chromatography (GC)-mass spectrometry (MS) analytical method for the simultaneous separation and determination of endocrine disrupting chemicals (EDCs) from water samples is described in detail. Important and contrasting EDCs including estrone, 17β-estradiol, 17α-ethynylestradiol, 16α-hydroxyestrone, 4-nonylphenol, bisphenol A and 4-tert-octylphenol were selected as the target compounds. The SPE technique, followed by the derivatisation with bis (trimethylsilyl) trifluoroacetamide was used for the extraction recoveries of target compounds from water samples. A number of parameters that may affect the recovery of EDCs, such as the type of SPE cartridges, eluents, as well as water properties including pH value, and concentration of salts and humic substances were investigated. It is shown that the Oasis cartridges produced the best recoveries of target EDCs while ethyl acetate was efficient in eluting EDCs from SPE cartridges. The recovery of some EDCs was enhanced by the addition of salt, but reduced by the increase in pH value and humic acid concentration. The optimised method was further verified by performing spiking experiments in natural river water and seawater matrices, with good recovery and reproducibility for all the selected compounds. The established method was successfully applied to environmental water samples from East and West Sussex, UK, for the determination of the target EDCs. © 2003 Elsevier B.V. All rights reserved.
Loganathan, P, Hedley, MJ, Bretherton, MR & Rowarth, JS 2004, 'Accounting for particle movement when assessing the dissolution of slow release fertilizers in field soils', NUTRIENT CYCLING IN AGROECOSYSTEMS, vol. 70, no. 1, pp. 77-84.
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Mahlia, TMI 2004, 'Methodology for predicting market transformation due to implementation of energy efficiency standards and labels', Energy Conversion and Management, vol. 45, no. 11-12, pp. 1785-1793.
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Mahlia, TMI, Masjuki, HH, Saidur, R & Amalina, MA 2004, 'Cost–benefit analysis of implementing minimum energy efficiency standards for household refrigerator-freezers in Malaysia', Energy Policy, vol. 32, no. 16, pp. 1819-1824.
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Mahlia, TMI, Masjuki, HH, Saidur, R & Amalina, MA 2004, 'Viewpoint', Energy Policy, vol. 32, no. 16, pp. 1783-1787.
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Nejadi, S & Gilbert, I 2004, 'Shrinkage cracking and crack control in restrained reinforced concrete members', ACI STRUCTURAL JOURNAL, vol. 101, no. 6, pp. 840-845.
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Cracking caused by shrinkage in restrained reinforced concrete members is considered both experimentally and analytically. Eight longitudinally restrained slab specimens with different reinforcement layouts were monitored for up to 150 days to measure the effects of shrinkage on the time-dependent development of direct tension cracking. Strains in both the reinforcement and the concrete were monitored throughout the tests. The age of the concrete when each crack developed, the crack locations, and the gradual change in crack widths with time were also recorded. An analytical model developed previously to study the problem by Gilbert is modified and recalibrated and the experimental results and analytical predictions are compared. The effects of varying the quantity of reinforcing steel, the bar diameter, and the bar spacing are studied to gain a clearer understanding of the mechanism of direct tension cracking caused by restrained shrinkage and the factors affecting it.
Nghiem, LD, Schäfer, AI & Elimelech, M 2004, 'Removal of Natural Hormones by Nanofiltration Membranes: Measurement, Modeling, and Mechanisms', Environmental Science & Technology, vol. 38, no. 6, pp. 1888-1896.
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Nguyen, TV, Vigneswaran, S, Huu, HN, Pokhrel, D & Viraraghavan, T 2004, 'Iron coated sponge in arsenic removal', Fluid - Particle Separations Journal, vol. 16, no. 2, pp. 175-184.
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Arsenic (As) contamination in water has raised a grave concern in many regions of the world. Arsenic can lead to a number of health problems even at very low concentration. This paper presents the laboratory-scale experimental results on the specific treatment technology: iron coated sponge (IOCSp) adsorption in As removal. The results indicated that IOCSp could remove 47.3% to 65% of As (III) and As (V) after a 1 hour contact with IOCSp (initial As concentration = 260 μg/l; 0.15g sponge/100ml solution). A nine hour-adsorption led to a very high As removal efficiency (more than 92.4% removal for both As (III) and As (V)). Each gram of IOCSp adsorbed about 160μg of As (III) and As (V) upon a 9 hour - contact of IOCSp with the As solution. After adsorption, IOCSp can be easily regenerated by NaOH.
Saco, PM & Kumar, P 2004, 'Kinematic dispersion effects of hillslope velocities', Water Resources Research, vol. 40, no. 1.
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When the flow parameters, such as celerity and hydrodynamic coefficient, are allowed to vary spatially within a basin, three mechanisms, namely, geomorphologic, kinematic, and hydrodynamic dispersion, contribute to the variance of the instantaneous response function. The relative contributions of the three dispersion mechanisms as a function of scale, or Strahler order of the basin, were studied earlier by Saco and Kumar [2002a, 2002b]. In this study we investigate the main mechanisms that are responsible for the variance when we take into account the hillslope dynamics. We use an approach similar to that derived by Saco and Kumar [2002a, 2002b], but for width functions, to compute the relative contributions of geomorphologic and kinematic dispersion due to hillslope celerities. We find that the kinematic dispersion due to hillslopes does not tend to reinforce the effect of geomorphologic dispersion; rather, it tends to counteract it. This means that the effect of hillslopes tends to “decrease” the variance induced by the geomorphology of the network. For hillslope celerities that are very small compared with channel celerities, the travel times in the hillslopes begin to be of the same order of magnitude as those in the network. If the celerity continues to decrease, all the variance is induced by the travel times at the hillslopes and the impact of geomorphologic dispersion becomes negligible.
Salim, W & Indraratna, B 2004, 'A new elastoplastic constitutive model for coarse granular aggregates incorporating particle breakage', Canadian Geotechnical Journal, vol. 41, no. 4, pp. 657-671.
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A new elastoplastic stressstrain constitutive model is developed for granular coarse aggregates incorporating the degradation of particles during triaxial shearing. Coarse granular aggregates are subjected to breakage during excessive stress changes. Most of the available constitutive models do not consider the degradation of particles during shearing. In the current model, a plastic flow rule has been developed incorporating the energy consumption due to particle breakage during shear deformation. A non-associated flow and a kinematic type yield locus have been adopted in the model. A general formulation for the rate of particle breakage during shearing has been developed and incorporated in the plastic flow rule. The effects of particle breakage on the plastic distortional and volumetric deformations are incorporated in the current model. The stressstrain formulations are developed within the general critical state framework. The model can accurately predict the stressstrain and volume change behaviour of coarse granular aggregates. The plastic dilation and contraction features of coarse aggregates at various confining pressures are well captured, and the strain-hardening and post-peak strain-softening behaviour of coarse granular media is adequately represented. A particular feature of the model is its capability to predict the degree of particle breakage at any stage of shear deformation.Key words: constitutive modelling, coarse granular aggregates, particle breakage, dilatancy, non-associated flow, plasticity.
Shim, WG, Chaudhary, DS, Vigneswaran, S, Ngo, HH, Lee, JW & Moon, H 2004, 'Mathematical modeling of granular activated carbon (GAC) biofiltration system', KOREAN JOURNAL OF CHEMICAL ENGINEERING, vol. 21, no. 1, pp. 212-220.
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In this study, a mathematical model of a fixed bed Granular Activated Carbon (GAC) biofiltration system was developed to predict the organic removal efficiency of the filter. The model consists of bulk transportation, adsorption, utilization, and biodegradation of organics. The variation of the specific surface area due to biofilm growth and the effect of filter backwash were also included in the model. The intrapellet diffusion and the diffusion of substrate in the biofilm were described by linear driving force approximation (LDFA) method. Biodegradation of organics was described by Monod kinetics. Sips adsorption isotherm was used to analyze the initial adsorption equilibrium of the system. The model showed that the organic removal efficiency of the biofilter greatly depends on the parameters related to the biological activities such as the maximum rate of substrate utilization (kmax) and biomass yield (Y) coefficients. Parameters such as suspended cell concentration (Xs) and decay constant (Kd) had little effects on the model simulation results. The filter backwash also had no significant impact on the performance of the biofilter.
Shon, HK, Guo, WS, Vigneswaran, S, Ngo, HH & Kim, IS 2004, 'Effect of flocculation in membrane-flocculation hybrid system in water reuse', SEPARATION SCIENCE AND TECHNOLOGY, vol. 39, no. 8, pp. 1871-1883.
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Preflocculation reduces the fouling of membranes in cross-flow microfiltration (CFM) thus leading to high quality product water at economic filtration flux. As such, this hybrid system will have a major impact in treating the biologically treated sewage effluent. The preflocculation achieved through the floating medium flocculation (FMF) was found to increase the phosphorus removal up to 96%. The decline in microfiltration permeate flux with time was reduced by the incorporation of flocculation. However, the improvement in the removal of dissolved organic carbon (DOC) was marginal from 20% with membrane alone to 46% with the membrane-flocculation hybrid system). The flocculation followed by adsorption its pre-treatment helped to increase the DOC removal as high as 98%. Flocculation was found to remove more than 66% of colloidal effluent organic matter (EfOM). An attempt was also made to quantify the hydrophobic fraction in the pretreated effluent and to identify the molecular weight (MW) range of organics removed by the flocculation. The pretreatment of flocculation was found to remove 68.5%, 61.8%, and 62.9% of hydrophobic, hydrophilic, and transphilic organic matter. The MW size distribution analysis indicated that flocculation with ferric chloride removed a majority of organic matter in the MW range of 300-5000 Da.
Shon, HK, Vigneswaran, S, Kim, IS, Cho, J & Ngo, HH 2004, 'Effect of pretreatment on the fouling of membranes: application in biologically treated sewage effluent', JOURNAL OF MEMBRANE SCIENCE, vol. 234, no. 1-2, pp. 111-120.
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Reuse of wastewater can help in maintaining environmental quality and relieving the unrelenting pressure on conventional and natural freshwater sources. Membrane processes find an important place in the wastewater treatment for reuse. Nonetheless, reverse osmosis (RO) and nanofiltration (NF), i.e. non-porous membranes require higher operational costs and energy. Thus, in this research NTR 7410 ultrafiltration (UF) membrane which is porous was used without and with pretreatment to treat biologically treated sewage effluent (BTSE). Four different pretreatment methods, namely, ferric chloride (FeCl3) flocculation, powdered activated carbon (PAC) adsorption, flocculation followed by adsorption, and granular activated carbon (GAC) biofilter were used in this study to compare their relative merits. Experimental results indicate that the most suitable pretreatment was flocculation followed by adsorption leading to a total organic carbon (TOC) removal of 90%. To assess the suitability of the membranes, it is important to conduct a detailed membrane characterization. The fouled NTR 7410 membrane surface was analyzed in terms of contact angle, zeta potential, attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR), scanning electron microscopy (SEM), flux decline, and TOC removal. The contact angle of the fouled membrane surface was lower than that of the clean membrane surface. This suggests that the majority of the foulants may have been the hydrophilic organic compounds such as polysaccharides, urea, etc. which are the extracellular enzyme of microorganisms in BTSE
Shon, HK, Vigneswaran, S, Kim, IS, Cho, J & Ngo, HH 2004, 'The effect of pretreatment to ultrafiltration of biologically treated sewage effluent: a detailed effluent organic matter (EfOM) characterization', WATER RESEARCH, vol. 38, no. 7, pp. 1933-1939.
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Ultrafiltration alone can remove only a portion of the effluent organic matter (EfOM) from biologically treated sewage effluent (BTSE). Use of pretreatment not only improves the EfOM removal but also reduces the membrane fouling. In this research, NTR 7410 ultrafiltration membrane was employed to remove EfOM from BTSE. Different pretreatments namely FeCl3 flocculation and powder activated carbon adsorption were evaluated. The highest removal of organic matter was observed when flocculation followed by adsorption was used as pretreatment. The flocculation and adsorption removed 68.5% and 71.4% of hydrophobic organics, respectively. The molecular weight (MW) of the EfOM in BTSE ranged from 300 to about 400,000Da. After the flocculation pretreatment, the majority of large MW organic matter was removed. The pretreatment of the flocculation followed by adsorption led to very high removal of both small and large organic matter. Further, this pretreatment led to practically no filtration flux decline. © 2004 Elsevier Ltd. All rights reserved.
Smith, PJ, Vigneswaran, S, Huu, HN, Ben-Aim, R & Nguyen, H 2004, 'Investigation of membrane de-clogging techniques in the Submerged Membrane Filtration Adsorption Hybrid System (SMFAHS)', Fluid - Particle Separations Journal, vol. 16, no. 2, pp. 165-173.
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Membrane clogging is a major obstacle to the successful operation of the membrane separation process. A submerged hollow fibre membrane with powdered activated carbon (PAC) adsorption (adsorption-membrane hybrid system) was used for the removal of organics from a synthetic wastewater representative of biologically treated sewage effluent. PAC usage successfully adsorbs the majority of the organics, and then the organic laden PAC is separated by the membrane reducing the direct organic loading to the membrane. However, membrane clogging still occurs. This study involved the development of an automation system and Supervisory Control and Data Acquisition (SCADA) system for performing an investigation and evaluation of three automated de-clogging techniques. The first de-clogging method involved the use of periodic relaxation, whereby permeate production for 12 minutes was periodically stopped for 3 minutes and the shear forces created by the aeration system and the absence of suction pressure during the relaxation period were used to de-clog the membrane. The second de-clogging method involved the use of a series of periodic back flush experiments with varied frequencies and durations to force permeate in the opposite direction out through the membrane pores. The optimal results in terms of de-clogging the membrane were achieved using a 15 second backflush after 15 minutes of permeate production. The third de-clogging method involved the application of an understanding of results of the periodic back flush series of experiments to design an automation system with a new approach to backflushing where an upper limit of a transmembrane pressure (TMP) increase each cycle was used to initiate the backflush. The transmembrane pressure represents the pressure measured across the membrane and it is a vital parameter indicating the degree of fouling of the membrane. A periodic backflush was found to be significantly more effective in terms of increasing the total ...
Stewart, MG 2004, 'Spatial variability of pitting corrosion and its influence on structural fragility and reliability of RC beams in flexure', Structural Safety, vol. 26, no. 4, pp. 453-470.
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A stochastic process for assessing the effect of spatial variability of pitting corrosion on structural reliability and fragility is developed for singly reinforced simply supported reinforced concrete (RC) beams in flexure. A distribution of pitting corrosion is inferred from existing literature. The RC beam is discretised into a series of elements and maximum pit depths are generated for each reinforcing steel bar in each element. The analysis considered various member spans, loading ratios, bar diameters and number of bars in a given cross-section. Comparisons made with general corrosion showed that pitting corrosion is more critical for smaller diameter reinforcing steel bars. It was also found that up to a three-fold increase in 50-year probabilities of failure were observed if spatial variability of pitting corrosion are included in the analysis when compared to probabilities of failure based on the mid-span limit states only. This strongly suggests that the inclusion of spatial variability of pitting corrosion can lead to significant decreases in structural reliability for flexural RC members. © 2004 Elsevier Ltd. All rights reserved.
Stewart, MG, Estes, AC & Frangopol, DM 2004, 'Bridge Deck Replacement for Minimum Expected Cost Under Multiple Reliability Constraints', Journal of Structural Engineering, vol. 130, no. 9, pp. 1414-1419.
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The present paper investigates the effect of limit state selection (strength versus serviceability) on bridge deck life-cycle costs and thus on optimal repair strategies. Such a comparison may then help determine whether safety or functionality (or both) are important criteria when optimizing bridge life-cycle performance and costs. The structural element under consideration is a reinforced concrete bridge deck; namely, a State Highway Bridge in Colorado. Two limit states are considered: ultimate strength and serviceability. The exceedence of either of the limit states considered herein will result in deck replacement; namely, if the reliability index falls below a target reliability index or if widespread cracking and spalling occurs. The life-cycle cost analysis includes expected replacement costs as well as the random variability of material properties, loads, section dimensions, model errors, chloride penetration, and corrosion rates. Life-cycle costs can then be compared for strength and serviceability limit state violations. Life-cycle costs for deck replacement based on a serviceability limit state were generally larger than those obtained for the strength limit states. Hence, an unrealistically optimistic life-cycle cost will result when serviceability is not included in the analysis.
Tien, VN, Chaudhary, DS, Ngo, HH & Vigneswaran, S 2004, 'Arsenic in water: Concerns and treatment technologies', JOURNAL OF INDUSTRIAL AND ENGINEERING CHEMISTRY, vol. 10, no. 3, pp. 337-348.
Vidal, T, Castel, A & François, R 2004, 'Analyzing crack width to predict corrosion in reinforced concrete', Cement and Concrete Research, vol. 34, no. 1, pp. 165-174.
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Vigneswaran, S, Shon, HK, Boonthanon, S, Ngo, HH & Aim, RB 2004, 'Membrane-flocculation-adsorption hybrid system in wastewater treatment: micro and nano size organic matter removal', WATER SCIENCE AND TECHNOLOGY, vol. 50, no. 12, pp. 265-271.
Wang, J 2004, 'Pseudolite Augmentation for GPS Aided Aerial Photogrammetry: An Analysis of Systematic Errors.', Geomatics Research Australasia, vol. 81, pp. 30-44.
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GPS has been widely used as a geo-referencing tool in aerial surveying. However, the accuracy and availability of GPS positioning cannot meet the stringent requirements of large-scale photogrammetry. Ground-based pseudolites can strengthen measurement geometry for GPS based airborne geo-referencing systems. As a result, positioning accuracy and reliability can be improved, especially in the vertical component. However, as pseudolites are comparatively close to receivers, some challenging issues in systematic error analyses and modeling need to be further investigated. In this paper, the major systematic errors related to pseudolites, such as tropospheric delay, multipath and pseudolite location errors are analysed, and their impacts on the performance of an integrated GPS/Pseudolite airborne geo- reference system are presented.
White, AB, Kumar, P, Saco, PM, Rhoads, BL & Yen, BC 2004, 'Hydrodynamic and geomorphologic dispersion: scale effects in the Illinois River Basin', Journal of Hydrology, vol. 288, no. 3-4, pp. 237-257.
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Wilding, A, Liu, R & Zhou, JL 2004, 'Validation of cross-flow ultrafiltration for sampling of colloidal particles from aquatic systems', Journal of Colloid and Interface Science, vol. 280, no. 1, pp. 102-112.
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The use of cross-flow ultrafiltration (CFF) for the isolation of colloids from the bulk aquatic matrices has been increasing over the last decade; however, a thorough validation of each CFF system is needed before its application to natural samples. Laboratory experiments have been conducted to validate a 1-kDa Millipore Pellicon 2 cartridge type CFF system, using a range of molecular probes spiked in natural waters. Using the separation data of these probes, key validation parameters have been calculated, including retention coefficient (RC), concentration factor (cf), colloid concentration, recovery, and mass balance. The permeation behaviour of these molecules has also been studied using a simple permeation model. Results show that good retention (>80%) of high molecular weight (HMW, >1 kDa) molecules and low retention (<20%) of low molecular weight (LMW, <1 kDa) molecules can be achieved at high cf values or over long timescales. In addition, permeation modelling and the calculation of colloid concentration demonstrate the same findings, again recommending high cf values or long timescales for ultrafiltration to minimise the retention of LMW molecules. The retention characteristics of 3-kDa dextran change slightly with salinity. Mass balance calculations show good recoveries for all of the molecules tested. The apparent membrane molecular cut-off of the CFF system has been estimated to be between 2.1 and 2.5 kDa, which is slightly greater than the manufacturer's nominal MW cut-off of 1 kDa. © 2004 Elsevier Inc. All rights reserved.
Wu, C, Hao, H, Lu, Y & Sun, S 2004, 'Numerical simulation of structural responses on a sand layer to blast induced ground excitations', Computers & Structures, vol. 82, no. 9-10, pp. 799-814.
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Wu, C, Lu, Y & Hao, H 2004, 'Numerical prediction of blast‐induced stress wave from large‐scale underground explosion', International Journal for Numerical and Analytical Methods in Geomechanics, vol. 28, no. 1, pp. 93-109.
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AbstractThis paper presents a numerical model for predicting the dynamic response of rock mass subjected to large‐scale underground explosion. The model is calibrated against data obtained from large‐scale field tests. The Hugoniot equation of state for rock mass is adopted to calculate the pressure as a function of mass density. A piecewise linear Drucker–Prager strength criterion including the strain rate effect is employed to model the rock mass behaviour subjected to blast loading. A double scalar damage model accounting for both the compression and tension damage is introduced to simulate the damage zone around the charge chamber caused by blast loading. The model is incorporated into Autodyn3D through its user subroutines. The numerical model is then used to predict the dynamic response of rock mass, in terms of the peak particle velocity (PPV) and peak particle acceleration (PPA) attenuation laws, the damage zone, the particle velocity time histories and their frequency contents for large‐scale underground explosion tests. The computed results are found in good agreement with the field measured data; hence, the proposed model is proven to be adequate for simulating the dynamic response of rock mass subjected to large‐scale underground explosion. Extended numerical analyses indicate that, apart from the charge loading density, the stress wave intensity is also affected, but to a lesser extent, by the charge weight and the charge chamber geometry for large‐scale underground explosions. Copyright © 2004 John Wiley & Sons, Ltd.
Zhang, ZL, Hong, HS, Zhou, JL & Yu, G 2004, 'Phase association of polycyclic aromatic hydrocarbons in the Minjiang River Estuary, China', Science of The Total Environment, vol. 323, no. 1-3, pp. 71-86.
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Persistent organic pollutants such as polycyclic aromatic hydrocarbons (PAHs) are of great concern due to their persistence, bioaccumulation and toxic effects. In this work the levels of 16 priority PAHs were determined in water, pore water, sediment, soil and vegetable samples from Minjiang River Estuary, China. Total PAH concentrations varied from 9.9 to 474 μg/l in water, 82.1 to 239 μg/l in pore water, 112 to 877 ng/g dry wt. in surficial sediments, 128 to 465 ng/g dry wt. in soil and 8600 to 111000 ng/g dry wt. in Chinese vegetables. Overall, the mean concentrations of PAHs were present in higher levels in pore water than that in surface water, due possibly to higher concentrations of dissolved organic carbon or colloids with which the hydrophobic pollutants were strongly associated. Such a concentration gradient implies a potential flux of pollutants from sediment pore water to overlying water. Contamination was dominated by high molecular mass PAH compounds in all samples, indicating combustion-derived sources (for example, pyrolysis at high temperature). The levels of PAHs in water and vegetable were relatively high in comparison to other studies, although PAHs in sediment and soil were comparable to those found in many other similar environments. The ratios of selected PAHs indicated again that PAHs in Minjiang River Estuary were mainly derived from incomplete combustion of fossil fuel. © 2003 Elsevier B.V. All rights reserved.
Zhao, LC, Wu, CQ & Wang, Q 2004, 'Berry–Esseen Bound for a Sample Sum from a Finite Set of Independent Random Variables', Journal of Theoretical Probability, vol. 17, no. 3, pp. 557-572.
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Let {X 1,...,X N} be a set of N independent random variables, and let S n be a sum of n random variables chosen without replacement from the set {X 1,...,X N} with equal probabilities. In this paper we give an estimate of the remainder term for the normal approximation of S n under mild conditions.
Ball, JE, Walker, JW, Isles, S & Blake, C 1970, 'Assessment of deposited sediments in roadside stormwater retention basins', Proceedings of the 8th National Conference on Hydraulics in Water Engineering, National Conference on Hydraulics in Water Engineering, Engineers Australia, Gold Coast, Australia, pp. 1-8.
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Previous studies have shown stormwater runoff from road surfaces to contain numerous contaminants. Most of these contaminants are bound to silt or clay sized particles. Hence, the fine sediments trapped in roadside retention basins may potentially have high concentrations of contaminants. This study was undertaken to assist in the development of a maintenance strategy for RTA retention basins. A key outcome from the study was determination of the contaminant concentrations in the sediments and hence the âWaste Classificationâ in accordance with the NSW EPA Waste Guidelines. Ten retention basins located on major highways in NSW were selected for the study. All retention basins were located in predominantly rural regions. Based on the chemical analysis of the sediments all contaminants except lead met the Inert classification criteria as outlined in the NSW EPA Waste Guidelines. Lead leachate concentrations in some samples (4 basins) were sufficiently high for the sediments to be classified as Solid Waste.
Brennan, J, Martin, EA & Kim, M 1970, 'Developing an ontology of Spatial Relations', Visual and Spatial Reasoning in Design III, Visual and Spatial Reasoning in Design, Key Centre of Design Computing and Cognition, MIT,Cambridge, USA, pp. 163-182.
Choi, KS & Ball, JE 1970, 'Monitoring the calibration of catchment modelling systems', Proceedings of the 6th International Conference on Hydroinformatics, International Conference on Hydroinformatics, World Scientific Publishing Co. Pte. Ltd, Singapore, pp. 203-213.
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The application of catchment modelling systems is now a common approach for management of catchments. Fundamental to the application of a catchment modelling system is the calibration and validation of the many control parameters used to ensure that the simulated catchment response adequately reproduces the actual catchment response. Recorded information about the actual catchment response is needed if this necessary calibration and validation process is to be undertaken. However, the recorded information typically used for operation of a catchment modelling system rarely, if ever, is error free. These errors have the potential to influence the calibration of the control parameters for a catchment modelling system. Traditional calibration approaches focus only on achieving the parameter values that result in the best curve-fitting between simulated and recorded data. Introduced herein is an Early Stopping Technique which is aimed at avoiding curve-fitting through monitoring improvements in the objective function used for determining the set of optimal control parameters. Application of this approach to the calibration of SWMM (Storm Water Management Model) on the Centennial Park catchment in Sydney is outlined.
Chua, B & Brennan, J 1970, 'Enhancing Collaborative Knowledge Management Systems Designs', Proceedings 5th European Conference on Knowledge Management, European Conference on Knowledge Management, Academic Conferences International, Paris, France, pp. 171-179.
Cox, R, Yee, M & Ball, JE 1970, 'Safety of People in Flooded Streets and Floodways', Proc. 8th National Conference on Hydraulics in Water Engineering, National Conference on Hydraulics in Water Engineering, Engineers Australia, Gold Coast, Australia, pp. 1-8.
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The safety of people on floodways or flooded streets is of major concern in urban stormwater design and floodplain management. Current design guidelines for safety on floodways (in Australia and overseas) are simplistic, generally given in terms of a critical value of Depth * Velocity (D*V) which has been based on limited laboratory testing. Cox and Ball (2001) updated the primal 1973 data for 6 children from Australia with tests of 3 adults from Japan. This paper incorporates further analysis of laboratory test data for adults from USA and Finland. The worldwide laboratory test data was found to be deficient in not testing very small/young children nor very frail/older persons. The authors have thus completed additional testing on 4 young children. A predictive model has been developed and proven against the test data for stability failure of human subjects. The commonly adopted guideline for designing floodways by specifying a critical Depth*Velocity (D*V) value of 0.4 m2s-1 does not ensure the safety of all children - young children with low muscular coordination (typified by Height*Mass values less than 20 mKg) are not safe at this criteria. It is most likely that many frail/older persons also may not be safe under this criteria.
Crews, KI, Samali, B, Bakoss, SL & Champion, C 1970, 'Overview of Assessing Load Carrying Capacity of Timber Bridges Using Dynamic Methods', Proceedings of the Austroads 2004 Bridge Conference, Austroads Bridge Conference, Austroads Incorporated, Hobart, Australia, pp. 1-12.
Crews, KI, Samali, B, Bakoss, SL & Champion, C 1970, 'Testing and Assessment Procedures to Facilitate the Management of Timber Bridges Assets', The 3rd Civil Engineering Conference in the Asian Region Proceedings, The 3rd Civil Engineering Conference in the Asia Region, Asian Civil Engineering Coordination Council, Seoul, Korea, pp. 229-234.
Ding, GK 1970, 'The development of a multi-criteria approach for the measurement of sustainable performance of housing projects', Sustainability of the Housing Projects, XXXII IAHS World Congress, Sustainability of the Housing Projects, Univeristy of Trento, Trento, Italy, pp. 1-10.
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It has long been recognised that environmental matters are important to the survival of the construction industry. Yet, in general, the construction industry continues to degrade the environment, exploiting resources and generating waste, and is reluctant to change its conventional practices to incorporate environmental matters as part of the decisionmaking process. Building development involves complex decisions and the increased significance of external effects has further complicated the situation. Cost benefit analysis (CBA) is one of the conventional tools used widely by public and private sectors when appraising projects. It sets out to measure and compare the total costs and benefits of different projects that are competing for scarce resources in monetary terms. However, there are growing concerns that the values of environmental goods and services are often ignored or underestimated in the CBA approach which has led to the overuse and depletion of environmental assets. Consequently, CBA's usefulness and relevance in this respect is increasingly controversial. Project development is not just concerned with financial return, but is also conscious of the long-term impacts on living standards for both present and future generations. Sustainable development is an important issue in project decision-making and environmental effects need to be incorporated into the evaluation process.
Dowling, DM, Samali, B & Li, J 1970, 'Shake Table Testing of Unreinforced and Highly Reinforced U-shape Adobe-Mudbrick Wall Units', Australian Earthquake Engineering in the New Millenium, Australian Earthquake Engineering Society 2004 Conference, Australian Earthquake Engineering Society, Mt Gambier, Australia, pp. 1-6.
Friolo, KH, Ray, AS, Stuart, BH & Thomas, P 1970, 'Degradation of historic sandstone buildings of Sydney', Proceedings of the 7th Australasian Masonry Conference, University of Newcastle, Newcastle, pp. 420-427.
Friolo, KH, Ray, AS, Stuart, BH & Thomas, P 1970, 'Thermal analysis of yellow block sandstones in Sydney's heritage buildings', 13th International Congress on Thermal Analysis and Calorimetry Book of Abstracts, 13th International Congress on Thermal Analysis and Calorimetry, Sardinia.
Glamore, W & Indraratna, B 1970, 'A two-stage decision support tool for restoring tidal flows to flood mitigation drains affected by acid sulfate soil: case study of Broughton Creek floodplain, New South Wales, Australia', Soil Research, 5th International Acid Sulfate Soil Conference, CSIRO Publishing, Tweed Heads, AUSTRALIA, pp. 639-639.
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A 2-stage flood estimation and water quality decision support tool (DST) was developed, calibrated, and applied to a field site in south-eastern New South Wales (NSW) to simulate tidal restoration in a flood mitigation drain affected by acid sulfate soils leachate. The first stage of the DST employs a digital terrain map, geographic information tools, and measured water levels to calculate drain water overtopping due to tidal variations. Simulations using the GIS technique at the study site indicated that the primary drainage network can safely contain full tidal flushing (0.91 m AHD or a 58% increase), whereas at the same level the secondary drainage network overtops along relict drainage channels. The second stage of the DST simulates the change in drain water quality using an ion-specific program code written within the open interface PHREEQC program. The results from the water quality model were calibrated against laboratory titration tests. Drain water pH was shown to increase above 6.0, and soluble aluminium and iron concentrations decreased by 73% and 56%, respectively. The extent of water quality change is directly related to the ionic strength of the intruding water and the ion-specific reaction kinetics of aluminium, iron, and sulfate.
Guo, W, Vigneswaran, S & Ngo, H 1970, 'A Rational Approach In Controlling Membrane Fouling Problems: Pretreatments to a submerged Hollow Fibre Membrane System', Water Environment - Membrane Technology Proceedings, IWA Specialty Conference, Water Environment-Membrane Technology, IWA, Seoul, Korea, pp. 517-524.
Guo, W, Vigneswaran, S, Ngo, H & Ben Aim, RM 1970, 'Performance of a Submerged Membrane Adsorption Hybrid System (SMAHS) in Wastewater Treatment for Reuse', 4th World Water congress: innovations in Drinking Water Treatment, IWA World Water Congress, IWA, Marrakech, Morocco, pp. 1-8.
Ha, QP, Wu, Y, Samali, B & Li, J 1970, 'Earthquake Response of a Building Model with Base-Isolated Active Control', Preprints of the 3rd IFAC Symposium on Mechatronics Systems, IFAC Symposium on Mechatronic Systems, Casual Productions, Glenelg North, SA, Sydney, Australia, pp. 687-692.
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Place published ?- CD ROM
Ha, QP, Wu, YM, Samali, B & Li, J 1970, 'Earthquake Response of a Building Model with Base-Isolated Active Control', IFAC Proceedings Volumes, Elsevier BV, pp. 641-646.
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Copyright © IFAC Mechatronic Systems, Sydney, Australia, 2004. Base-isolated active control is employed in this paper for the protection of tall buildings against strong earthquakes with application to a five-storey benchmark building model. The control system consists of a base isolation system (laminated rubber bearings) connected to an active control system (a tuned mass damper and an actuator). Linear functional observers are used to reconstruct the control signal for systems with a limited number of sensors. The effectiveness of the proposed control system is tested with different ground motions: El-Centro 1940. Hachinohe 1968, Kobe 1995, and Northridge 1994 earthquakes. Numerical results show that the rubber bearing system alone can perform well against Hachinohe, Kobe, and Northridge ground motions, but not well enough to protect the model against El-Centro ground motion. With an active control system implemented to the rubber-isolated model, significant improvements in earthquake resistance against these four earthquakes arc obtained, especially against the El-Centro.
Indraratna, B, Khabbaz, H & Salim, W 1970, 'A laboratory study on improvement of railway ballast using geosynthetics', GEOTECHNICAL ENGINEERING FOR TRANSPORTATION PROJECTS, VOL 1, GeoTrans 2004 - Geotechnical Engineering for Transportation Projects, ASCE, Los Angeles, California, USA, pp. 617-626.
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The classical railway track basically consists of a flat framework made up of rails and sleepers, which are supported on ballasted track formation. Ballast particles breakdown and deteriorate progressively under heavy cyclic rail loading. Moreover, excessive consolidation settlement and progressive shear failure may occur in soft track formation under repetitive stresses. In order to rectify these problems, frequent maintenance operations are generally required in ballasted track. In order to minimize the deterioration of track substructure and also to reduce maintenance cost, the use of various types of geosynthetics including recycling of waste ballast have been studied in the laboratory. The prospective use of three types of geosynthetics (i.e. geogrids, geotextiles and geocomposites) in enhancing the performance of fresh and recycled ballast has been examined. The aspects of deformation and degradation of ballast under cyclic loading have been studied using a large-scale prismoidal triaxial rig. The research findings reveal that recycled ballast stabilized with geosynthetic reinforcement has a good potential for resilient track construction and for reducing the cost of track maintenance. The experimental findings may be beneficial to the railway engineers and encourage them to upgrade current tracks based on these innovative techniques.
Indraratna, B, Raut, A & Locke, M 1970, 'Granular Filters in Embankment Dams: A Conceptual Overview and Experimental Investigation', Geo Jordan 2004, Geo Jordan Conference 2004, American Society of Civil Engineers, pp. 15-34.
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In contrast to empirical design, rigorous analytical modeling and numerical simulations provide useful predictions on time-dependent changes in filters, and the potential rate of base soil erosion from the dame core under various geo-hydraulic constraints. Moreover, simulation of filtration phenomenon by numerical schemes provides a good idea of the minimum filter thickness, based on its retention capacity. In this Keynote paper, governing equations are developed considering the principles of mass and momentum conservation combined with appropriate seepage criteria and the equations are solved by finite difference procedure to simulate the time-dependent changes in filters. The important contribution of various void models and seepage conditions assumed by various researchers are discussed and compared, identifying their scope and limitations within the framework of practical dam engineering. The theoretical developments are verified through large-scale laboratory testing for both cohesive and non-cohesive base soils.
Ip, K, Ray, AS, Stuart, BH & Thomas, P 1970, 'Degradation of historic sandstone buildings of Sydney', Proceedings of the 7th Australasian Masonry Conference, Australian Masonary Conference, University of Newcastle, Australia, pp. 420-427.
Kalam, MA, Masjuki, HH, Maleque, MA, Amalina, MA, Abdesselam, H & Mahlia, TMI 1970, 'Air -Fuel Ratio Calculation for a Natural Gas Fuelled Spark Ignition Engine', SAE Technical Paper Series, SAE 2004 World Congress & Exhibition, SAE International.
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Air-fuel ratio (AFR) is a crucial parameter for combustion controls in internal combustion engines. An incorrect AFR metering for reciprocating internal combustion engine causes high toxic gases emissions formulation, serious fuel consumption problems and unbearable combustion noise and combustion deterioration. Traditionally, the AFR is obtained by direct measurement of intake air and the fuel either injected into the combustion chamber or pre-mixed at the carburetor. However, the accurate AFR obtained from direct measurement is difficult due to measuring equipments resolution prone to errors. This paper describes a method for accurate determination of air-fuel ratio based on exhaust emission gas analysis as an additional tool used to be validated the conventional direct air fuel flow rates measurement. This method explains all the possible parameters that may affect the accuracy of air-fuel ratio measurement which includes the instrument error, ambient conditions, the assumed water-gas shift reaction constant, the humidity of the atmospheric air and the inclusion of nitrogen in the air-fuel ratio model. Results show that four essential exhaust gas emission concentrations, namely carbon monoxide (CO), carbon dioxide (CO2), oxygen (O2) and unburn hydrocarbons (HCs) are adequate for obtaining an accurate air-fuel ratio. The fuel type and the range of parameters that may affect the accuracy of air-fuel ratio are properly defined. This paper will also present experimental results of a bi-fuel natural gas spark ignition engine to be compared with computational results. The results of this investigation will be used to develop a new dedicated natural gas engine. Copyright © 2004 SAE International.
Nguyen, V, Vigneswaran, S, Ngo, H, Pokhrel, D & Viraraghavan, T 1970, 'Arsenic Removal by Iron Coated Sponge in Drinking Water Treatment', The 2nd International Symposium on Southeast Asian Water Environment, The Second International Symposium on Southeast Asian Water Environment, The University of Tokyo, Hanoi, Vietnam, pp. 214-221.
Rankin, K & Ball, JE 1970, 'A Review of the Performance of Porous Pavers', Proceedings of the 2004 International Conference on Water Sensitive Urban Design (WSUD 2004), International Conference on Water Sensitive Urban Design, Engineers Australia, Adelaide, Australia, pp. 366-377.
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Urban stormwater runoff is a transport medium for many contaminants from anthropogenic sources. There are many alternative management strategies available to treat these contaminants. One of the technologies suggested for this purpose is the use of permeable pavements to minimise the quantity of surface runoff generated by impervious surfaces within an urban catchment. Reported herein are the results of a monitoring program undertaken to assess the effectiveness of permeable pavers for reducing the quantity and quality of stormwater runoff. It was found that the catchment where a Rocla Ecoloc paver was installed had the effective imperviousness reduced from 45% prior to reconstruction of the road surface with the permeable pavers to less than 5% after reconstruction of the road. At the same time, the quality of the surface runoff was found to be at the lower levels of runoff from road surfaces while no increase in stormwater contaminants within the groundwater system was monitored.
Shon, H, Vigneswaran, S, Kim, IS, Cho, J & Ngo, H 1970, 'Characterization of Different Treatments With Biologically Treated Sewage Effluent and Synthetic Wastewater', Enviro 04 Convention & Exhibition, Enviro 04, Enviroaust Convention Limited, Darling Harbour, Australia, pp. 1-10.
Shon, H, Vigneswaran, S, Kim, J, Ngo, H & Park, N 1970, 'Comparison of Nanofiltration with Flocculation-Microfiltration-Photocatalysis Hybrid System in Dissolved Organic Matter Removal', 9th World Filtration Congress, World Filtration Congress, The American Filtration and Separation Society, New Orleans, Louisiana, USA, pp. 1-19.
Turner, BD, Binning, P & Sloan, S 1970, 'The CO2 enhanced removal of fluoride using a calcite permeable reactive barrier', GEOCHIMICA ET COSMOCHIMICA ACTA, 14th Annual V M Goldschmidt Conference, PERGAMON-ELSEVIER SCIENCE LTD, Univ Copenhagen, Copenhagen, DENMARK, pp. A460-A460.
Westra, S & Ball, JE 1970, 'On the Propagation of Errors in Catchment Modelling Systems', Proceedings of the 6th International Conference on Hydroinformatics, International Conference on Hydroinformatics, World Scientific Publishing Co. Pte. Ltd, Singapore, pp. 340-350.
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White, R, Phillips, MR, Thomas, P, Wuhrer, R & Dredge, P 1970, 'Interactions Between Pigments in 19th and Early 20th Century Oil Paintings - In Situ Studies Using the Environmental Scanning Electron Microscope', Microscopy and Microanalysis, Microscopy and Microanalysis, Oxford University Press (OUP), Savannah, USA, pp. 132-133.
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Extended abstract of a paper presented at Microscopy and Microanalysis 2004 in Savannah, Georgia, USA, August 1–5, 2004.
Wu, CQ, Hao, H & Lu, Y 1970, 'Numerical simulation of damage of masonry and masonry infilled RC frame structures to blast ground motions', PROCEEDINGS OF THE EIGHTH INTERNATIONAL SYMPOSIUM ON STRUCTURAL ENGINEERING FOR YOUNG EXPERTS, VOLS 1 AND 2, 8th International Symposium on Structural Engineering for Young Experts, SCIENCE PRESS BEIJING, Xian, PEOPLES R CHINA, pp. 523-529.
