Ball, JE 2003, 'Hydraulic grade lines in urban stormwater systems – do they predict surcharge conditions?', Australasian Journal of Water Resources, vol. 6, no. 2, pp. 169-176.
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The 1977 edition of Australian Rainfall and Runoff introduced the concept of Hydraulic Grade Lines (HGLs) as a measure of the surcharge potential for piped or underground urban stormwater drainage systems. This concept was included also in the 1987 edition of Australian Rainfall and Runoff. As a result of these publications, many authorities vested with management of urban stormwater drainage systems use the HGL to locate potential surcharges from their underground stormwater drainage systems. This acceptance of the importance of HGLs for the prediction of surcharge conditions in underground stormwater drainage systems, however, has been without serious consideration of the hydraulics of underground stormwater systems.
Baweja, D, Roper, H & Sirivivatnanon, V 2003, 'Improved electrochemical determinations of chloride-induced steel corrosion in concrete', ACI MATERIALS JOURNAL, vol. 100, no. 3, pp. 228-238.
Bowman, JC, Readman, JW & Zhou, JL 2003, 'Seasonal variability in the concentrations of Irgarol 1051 in Brighton Marina, UK; including the impact of dredging', Marine Pollution Bulletin, vol. 46, no. 4, pp. 444-451.
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Variations in Irgarol 1051 concentrations in the UK's largest marina at Brighton were determined regularly over a period of one year. Aqueous concentrations ranged from <1 to 960 ngl-1 with highest mean concentrations generally associated with berths for larger vessels and with the main channels. Temporally, highest concentrations were recorded in November through to January and were probably associated with maintenance of vessels in an adjacent boatyard. Elevated levels were also encountered at the beginning of the season, coinciding with the introduction of newly antifouled vessels. Increased concentrations also followed dredging, possibly through re-mobilisation of Irgarol 1051. No correlations were found between dissolved Irgarol 1051 concentrations and pH, temperature or salinity. With the exception of sporadically high concentrations recorded for water samples (probably taken in close proximity to recently antifouled vessels), concentrations rarely exceeded the no observed effect concentration for marine periphyton of 63 ngl-1. Concentrations of Irgarol 1051 in sediments sampled from the marina ranged from <1 to 77 ngg-1. Apparent distribution coefficients (Kd) calculated from sedimentary and aqueous samples (collected simultaneously) are generally within the range of Kd's reported from laboratory experiments. © 2003 Elsevier Science Ltd. All rights reserved.
Bowman, JC, Readman, JW & Zhou, JL 2003, 'Sorption of the natural endocrine disruptors, oestrone and 17 beta-oestradiol in the aquatic environment', Environmental Geochemistry and Health, vol. 25, no. 1, pp. 63-67.
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Brown, LD, Ray, AS & Thomas, PS 2003, 'Si-29 and Al-21 NMR study of amorphous and paracrystalline opals from Australia', JOURNAL OF NON-CRYSTALLINE SOLIDS, vol. 332, no. 1-3, pp. 242-248.
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Four opal-AG (amorphous) and two opal-CT (paracrystalline) samples obtained from various regions in Australia were investigated with 29Si NMR and 27Al NMR. The proton cross-polarization 29Si NMR technique was used and the resulting spectra consisted of two main resonances: -102.0 and -111.2 ppm for opal-AG; and -102.5 and -112.2 ppm for opal-CT. These peaks were assigned to the Q3(1OH) and Q4 resonances, respectively. Using very short contact times, a third, very weak peak at -94 ppm was resolved in an opal-CT specimen, which was assigned to silicon in the Q2(2OH) arrangement (i.e. a silicon with twin hydroxyl groups). It was found that the opal-CT samples contained a higher proportion of both geminal and vicinal silanol groups (Q2 and Q3) than the opal-AG samples. The geminal silanol groups present in opal-AG and opal-CT are not restricted to opal-AN. The full-width at half-maximum (FWHM) values were 9.5 ppm for the opal-AG samples, and 6.5 ppm for both opal-CT samples, a result which confirms that opal-CT has a higher degree of short-range structural order than opal-AG. The 27Al NMR spectra of the opals all showed a single resonance at +52 ppm, indicating that the aluminium exists in a tetrahedral arrangement incorporated within the opal structure.
Castel, A, Vidal, T, François, R & Arliguie, G 2003, 'Influence of steel–concrete interface quality on reinforcement corrosion induced by chlorides', Magazine of Concrete Research, vol. 55, no. 2, pp. 151-159.
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To evaluate the degree of corrosion, reinforcements of 14-year-old and 17-year-old concrete members were completely exposed. These 3 m long beams were stored in three-point flexion in an aggressive environment consisting in sequences of drying and wetting by a salt fog (35 g/l of NaCl). The total chloride content was also measured at the level of all reinforcements. The chloride content appears to be significantly higher than the threshold that is generally used to evaluate corrosion initiation. A comparative analysis carried out on these experimental results shows that the steel–concrete interface quality (physical adhesion between steel and concrete) is greatly determinant to predict the initiation of corrosion in reinforced concrete members.
Chaudhary, DS, Vigneswaran, S, Jegatheesan, V, Ngo, HH, Moon, H, Shim, WG & Kim, SH 2003, 'Granular activated carbon (GAC) adsorption in tertiary wastewater treatment: experiments and models', WATER SCIENCE AND TECHNOLOGY, vol. 47, no. 1, pp. 113-120.
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Wastewater treatment has always been a major concern in the developed countries. Over the last few decades, activated carbon adsorption has gained importance as an alternative tertiary wastewater treatment and purification process. In this study, granular activated carbon (GAC) adsorption was evaluated in terms of total organic carbon (TOC) removal from low strength synthetic wastewater. This paper provides details on adsorption experiments conducted on synthetic wastewater to develop suitable adsorption isotherms. Although the inorganics used in the synthetic wastewater solution had an overall unfavourable effect on adsorption of organics, the GAC adsorption system was found to be effective in removing TOC from the wastewater. This study showed that equation of state (EOS) theory was able to fit the adsorption isotherm results more precisely than the most commonly used Freundlich isotherm. Biodegradation of the organics with time was the most crucial and important aspect of the system and it was taken into account in determining the isotherm parameters. Initial organic concentration of the wastewater was the determining factor of the model parameters, and hence the isotherm parameters were determined covering a wide range of initial organic concentrations of the wastewater. As such, the isotherm parameters derived using the EOS theory could predict the batch adsorption and fixed bed adsorption results of the multi-component system successfully. The isotherm parameters showed a significant effect on the determination of the mass transfer coefficients in batch and fixed bed systems.
Chaudhary, DS, Vigneswaran, S, Ngo, H, Shim, WG & Moon, H 2003, 'Granular Activated Carbon (GAC) Biofilter for Low Strength Wastewater', Environmental Engineering Research, vol. 8, no. 4, pp. 184-192.
Chaudhary, DS, Vigneswaran, S, Ngo, HH, Kim, SH & Moon, H 2003, 'Comparison of association theory and Freundlich isotherm for describing granular activated carbon adsorption of secondary sewage effluent', JOURNAL OF ENVIRONMENTAL ENGINEERING AND SCIENCE, vol. 2, no. 2, pp. 111-118.
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Adsorption equilibria and kinetics are important to evaluate the effectiveness of an adsorption system. In this study, the adsorption behavior of organics in secondary effluent from a sewage treatment plant was investigated, using granular activated carbon (GAC) as an adsorbent. This paper provides details on the adsorption experiments conducted in a sewage treatment plant, and emphasizes the suitability of the association theory for describing adsorption characteristics of secondary sewage. The association theory was found to describe the overall adsorption equilibrium of the sewage system more precisely (with 0.33% error) than the more commonly-used Freundlich isotherm (with 9.9% error). The linear driving force approximation (LDFA) model and the fixed bed dynamics were used to predict the batch kinetics and the fixed bed adsorption experimental results respectively. The prediction was only slightly better when the isotherm parameters estimated from the association theory were used. Average errors in predicting batch and fixed bed experimental results were 0.25 and 0.55% with the association theory, and 0.34 and 0.75% with the Freundlich isotherm, respectively. © 2003 NRC Canada.
Chaudhary, DS, Vigneswaran, S, Ngo, HH, Kim, SH & Moon, H 2003, 'Effects of biodegradation and background inorganic substances on granular activated carbon adsorption of wastewater', SEPARATION SCIENCE AND TECHNOLOGY, vol. 38, no. 11, pp. 2515-2531.
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Background inorganic substances are thought to disrupt the adsorption process used in wastewater treatment systems. In this study, a low-strength synthetic wastewater was investigated for biodegradation and adsorption onto granular activated carbon, with and without the presence of background inorganic compounds. Overall, organic compounds in the synthetic wastewater underwent slow biodegradation, but when a solution was prepared with only one or two individual organic components present in the wastewater, biodegradation ceased. This effect was noticed both in the presence and absence of inorganic compounds. The association theory was found to describe the overall adsorption equilibrium of the system better than the more commonly used Freundlich isotherm. The isotherm patterns of the synthetic wastewater indicated that the dissolved inorganic substances had unfavorable effects on the adsorption of dissolved organic substances.
Chaudhary, DS, Vigneswaran, S, Ngo, HH, Shim, WG & Moon, H 2003, 'Biofilter in water and wastewater treatment', KOREAN JOURNAL OF CHEMICAL ENGINEERING, vol. 20, no. 6, pp. 1054-1065.
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Biofilter is one of the most important separation processes that can be employed to remove organic pollutants from air, water, and wastewater. Even though, it has been used over a century, it is still difficult to explain theoretically all the biological processes occurring in a biofilter. In this paper, the fundamental of biological processes involved in the biofilter is critically reviewed together with the mathematical modeling approach. The important operating and design parameters are discussed in detail with the typical values used for different applications. The most important parameter which governs this process is the biomass attached to the medium. The relative merits of different methods adopted in the measurement of the biomass are discussed. The laboratory-and full-scale applications of the biofilter in water and wastewater treatment are also presented. Their performances in terms of specific pollutant removal are highlighted.
Chiemchaisri, C, Panchawaranon, C, Rutchatanunti, S, Kludpiban, A, Ngo, HH & Vigneswaran, S 2003, 'Development of floating plastic media filtration system for water treatment and wastewater reuse', JOURNAL OF ENVIRONMENTAL SCIENCE AND HEALTH PART A-TOXIC/HAZARDOUS SUBSTANCES & ENVIRONMENTAL ENGINEERING, vol. 38, no. 10, pp. 2359-2368.
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Crews, KI 2003, 'Development of Durability Design Processes for Timber Structures', Australian Journal of Structural Engineering, vol. 4, no. 3, pp. 157-167.
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Cronin, SJ, Neall, VE, Lecointre, JA, Hedley, MJ & Loganathan, P 2003, 'Environmental hazards of fluoride in volcanic ash: a case study from Ruapehu volcano, New Zealand', JOURNAL OF VOLCANOLOGY AND GEOTHERMAL RESEARCH, vol. 121, no. 3-4, pp. 271-291.
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The vent-hosted hydrothermal system of Ruapehu volcano is normally covered by a c. 10 million m3 acidic crater lake where volcanic gases accumulate. Through analysis of eruption observations, granulometry, mineralogy and chemistry of volcanic ash from the 1995-1996 Ruapehu eruptions we report on the varying influences on environmental hazards associated with the deposits. All measured parameters are more dependent on the eruptive style than on distance from the vent. Early phreatic and phreatomagmatic eruption phases from crater lakes similar to that on Ruapehu are likely to contain the greatest concentrations of environmentally significant elements, especially sulphur and fluoride. These elements are contained within altered xenolithic material extracted from the hydrothermal system by steam explosions, as well as in residue hydrothermal fluids adsorbed on to particle surfaces. In particular, total F in the ash may be enriched by a factor of 6 relative to original magmatic contents, although immediately soluble F does not show such dramatic increases. Highly soluble NaF and CaSiF6 phases, demonstrated to be the carriers of 'available' F in purely magmatic eruptive systems, are probably not dominant in the products of phreatomagmatic eruptions through hydrothermal systems. Instead, slowly soluble compounds such as CaF2, AlF3 and Ca5(PO4)3F dominate. Fluoride in these phases is released over longer periods, where only one third is leached in a single 24-h water extraction. This implies that estimation of soluble F in such ashes based on a single leach leads to underestimation of the F impact, especially of a potential longer-term environmental hazard. In addition, a large proportion of the total F in the ash is apparently soluble in the digestive system of grazing animals. In the Ruapehu case this led to several thousand sheep deaths from fluorosis. © 2002 Elsevier Science B.V. All rights reserved.
Faber, MH & Stewart, MG 2003, 'Risk assessment for civil engineering facilities: critical overview and discussion', Reliability Engineering & System Safety, vol. 80, no. 2, pp. 173-184.
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The present paper should be seen as a basis for discussion of important aspects of risk analysis and assessment, as well as attempting to describe risk assessment in accordance with the present state of the art. Risk assessment is thus presented in an overview form from the viewpoint of being a means for decision-making and thus within the formal framework of decision theory. First the motivation for risk analysis is given and the theoretical basis together with the practical aspects, methodologies and techniques for the implementation of risk assessment in civil engineering applications are explained and discussed. The paper furthermore addresses the problems associated with risk acceptance criteria, risk aversion and value of human life and attempts to provide suggestions for the rational treatment of these aspects. Finally a number of problem areas are highlighted and the needs for further education, research and dissemination are stressed. © 2003 Elsevier Science Ltd. All rights reserved.
Grace, ND, Loganathan, P, Hedley, MJ & Wallace, GC 2003, 'Ingestion of soil fluorine: its impact on the fluorine metabolism and status of grazing young sheep', NEW ZEALAND JOURNAL OF AGRICULTURAL RESEARCH, vol. 46, no. 4, pp. 279-286.
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When young sheep ingested soil fluorine (F) at moderate to high rates (69–184 mg F day−1 for 63 days) the apparent absorption of F ranged from 44 to 53%, while apparent retention of F ranged from 28 to 42%. The respective values for ingestion of sodium fluoride (NaF) at 69 mg F day−1 were 69% and 39–45%. Increasing F intakes had little effect on kidney and liver F concentrations, but markedly increased the bone F concentrations in the sheep fed NaF or soil with high levels of F. Further, serum F concentration and the rate of F accumulation in bone were related to soil F intake. The rate of F accumulation in bone was curvilinearly related to serum F concentration, and serum F concentration had to be > 0.25 mg litre−1 before a significant accumulation of F occurred in bone. Serum F concentration could be a useful index to assess the soil F intakes and F status of grazing sheep. An examination of the sheep during and at the end of the study showed no clinical signs of fluorosis, such as mottled teeth or bone abnormalities. © 2003 Taylor & Francis Group, LLC.
Indraratna, B, Bamunawita, C, Redana, IW & McIntosh, G 2003, 'Modelling of prefabricated vertical drains in soft clay and evaluation of their effectiveness in practice', Ground Improvement, vol. 7, no. 3, pp. 127-137.
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Prefabricated vertical band drains are rapidly increasing in popularity as one of the most cost-effective soft clay improvement techniques worldwide. Nevertheless, problems caused during installation (such as the smear effect), drain clogging and well resistance of long drains contribute to retarded pore pressure dissipation, making these drains less effective in the field. This leads to reduced settlement compared with that which would be expected from ideal drains. This paper is an attempt to discuss, comprehensively, the modelling aspects of prefabricated vertical drains and to interpret the actual field data measured in a number of case studies that demonstrate their advantages and drawbacks. Both analytical and numerical modelling details are elucidated, based on the authors' experience and other research studies. Where warranted, laboratory data from large-scale experimental facilities are highlighted.
Indraratna, B, Bamunawita, C, Redana, IW & McIntosh, G 2003, 'Modelling of prefabricated vertical drains in soft clay and evaluation of their effectiveness in practice', Proceedings of the Institution of Civil Engineers - Ground Improvement, vol. 7, no. 3, pp. 127-137.
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Prefabricated vertical band drains are rapidly increasing in popularity as one of the most cost-effective soft clay improvement techniques worldwide. Nevertheless, problems caused during installation (such as the smear effect), drain clogging and well resistance of long drains contribute to retarded pore pressure dissipation, making these drains less effective in the field. This leads to reduced settlement compared with that which would be expected from ideal drains. This paper is an attempt to discuss, comprehensively, the modelling aspects of prefabricated vertical drains and to interpret the actual field data measured in a number of case studies that demonstrate their advantages and drawbacks. Both analytical and numerical modelling details are elucidated, based on the authors' experience and other research studies. Where warranted, laboratory data from large-scale experimental facilities are highlighted. Les drains verticaux préfabriqués deviennent de plus en plus populaires car ils forment l'une des techniques des plus rentables d'amélioration de l'argile tendre. Néanmoins, les problèmes causés pendant l'installation (comme l'effet de rémanence), l'occlusion des drains et la résistance des puits dans le cas de drains longs, contribuent à retarder la dissipation de pression interstitielle, ce qui rend ces drains moins efficaces sur le terrain. Ceci cause un tassement inférieur à celui qu'on attend normalement de drains parfaits. Cette étude essaie d'évaluer, de manière globale, les aspects de modélisation de drains verticaux préfabriqués et d'interpréter les données réelles relevées sur le terrain dans un certain nombre d'études de cas qui montrent leurs avantages et leurs inconvénients. Nous expliquons les détails de la modélisation analytique et numérique en nous basant sur notre expérience ainsi que sur d'autres recherches. Partout où cela est nécessaire, nous donnons aussi les données relevées en laboratoire dans une i...
Indraratna, B, Ranjith, PG, Price, JR & Gale, W 2003, 'Two-Phase (Air and Water) Flow through Rock Joints: Analytical and Experimental Study', Journal of Geotechnical and Geoenvironmental Engineering, vol. 129, no. 10, pp. 918-928.
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Kalam, MA & Masjuki, HH 2003, 'Effect of palm oil methyl ester and its emulsions on lubricant degradation and engine component wear', Lubrication Science, vol. 16, no. 1, pp. 57-65.
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AbstractThis paper presents the results of experimental work carried out to evaluate the effect of palm oil methyl ester also known as palm oil diesel (POD) and its emulsions, as alternative fuels, on unmodified indirect‐injection diesel engine wear and lubricant oil deterioration compared with ordinary diesel (OD). A constant 2500 rpm engine setting at half throttle was maintained throughout the wear debris and lubricant oil analysis period for 20 h for each fuel system. Samples of lubricant oil were collected through a one‐way valve connected to the crankcase sump at intervals of 4 h. The first sample was collected immediately after the engine had warmed up. The same lubricating oil, a conventional SAE 30, was used for all experiments. A multi‐element oil analyser was used to measure metal wear debris and lubricating oil additive depletion for the used lubricating oil. An ISL automatic houillon viscometer (ASTM D 445) and potentiometric titration (ASTM D 2896) were used to measure the viscosity and total base number, respectively.The lubricant oil analysis results for POD, OD, and their emulsions containing 10% water by volume were compared. Very promising results were obtained. The accumulation of metal wear debris in crankcase oil samples was lower with POD and its emulsion compared with the OD fuel. The addition of 10% water (by volume) to POD showed a promising tendency for wear resistance.
King, AJ, Readman, JW & Zhou, JL 2003, 'The application of solid-phase micro-extraction (SPME) to the analysis of polycyclic aromatic hydrocarbons (PAHs)', Environmental Geochemistry and Health, vol. 25, no. 1, pp. 69-75.
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Mahlia, TMI 2003, 'CO2 taxation on electricity generation for trees replanting in Malaysia', Energy Conversion and Management, vol. 44, no. 5, pp. 723-730.
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Mahlia, TMI, Abdulmuin, MZ, Alamsyah, TMI & Mukhlishien, D 2003, 'Dynamic modeling and simulation of a palm wastes boiler', Renewable Energy, vol. 28, no. 8, pp. 1235-1256.
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Mahlia, TMI, Masjuki, HH, Saidur, R, Choudhury, IA & NoorLeha, AR 2003, 'Projected electricity savings from implementing minimum energy efficiency standard for household refrigerators in Malaysia', Energy, vol. 28, no. 7, pp. 751-754.
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Meck, E & Sirivivatnanon, V 2003, 'Field indicator of chloride penetration depth', CEMENT AND CONCRETE RESEARCH, vol. 33, no. 8, pp. 1113-1117.
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Mitchell, AD, Loganathan, P, Payn, TW & Olykan, ST 2003, 'Magnesium and potassium fertiliser effects on foliar magnesium and potassium concentrations and upper mid-crown yellowing in Pinus radiata', New Zealand Journal of Forestry Science, vol. 33, no. 2, pp. 225-243.
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Upper mid-crown yellowing (UMCY) is a disorder in Pinus radiata D.Don caused mainly by a high potassium/magnesium (K/Mg) ratio in the soil exchange complex and in the tree needles. To study the effects of a range of soil exchangeable K/Mg ratios on potassium and magnesium uptake and UMCY in P. radiata, a trial was established in September 1996 on a Pumice Soil in northern Kaingaroa Forest in the central North Island of New Zealand in a second-rotation stand of 20-year-old P. radiata. The trial tested the effects of magnesium applied as kieserite at 200 kg Mg/ha and potassium applied as potassium sulphate at 200 and 400 kg K/ha on soil-exchangeable and soil-solution magnesium and potassium, on free needle magnesium and potassium, and on severity of UMCY. The applications of magnesium and the two rates of potassium significantly (p<0.05) increased soil-exchangeable and soil-solution magnesium and potassium concentrations respectively in the top 10 cm soil depth during the first 2 years of the trial (1997 and 1998). Magnesium application significantly (p<0.05) reduced the soil-exchangeable K/Mg ratio from 0.7-1.3 (control treatment) to 0.2-0.3, whereas the low and high rates of potassium application significantly increased this ratio to 0.8-1.7 and 1.3-2.5 respectively in the 2 years. The magnesium fertiliser application significantly (p<0.1) increased tree foliage magnesium concentration in 1999, but had no effect on foliage K/Mg ratios in any of the 4 years of sampling (1997, 1998, 1999, and 2002). Potassium fertiliser at the high rate significantly (p<0.1) increased the foliar potassium concentration in 1998 and 2002. Neither magnesium nor potassium fertiliser application had any effect on the change in foliar magnesium, potassium, or K/Mg ratio between 1997 and any of the other years sampled. Individual tree UMCY values ranged from 1 to 6 in a system of increasing severity from 1 to 8. Magnesium fertiliser significantly (p=0.074) reduced UMCY values (a...
Ngo, H, Jegatheesan, V & Vigneswaran, S 2003, 'High Rate Filtration Using Bouyant Medium: Experiments and Mathematical Models', Water Intelligence Online, vol. N/A, no. NA, pp. 1-9.
Samali, B, Al-Dawod, M & Li, JC 2003, 'Performance of an Active Mass Driver system on a five storey benchmark model', JSME INTERNATIONAL JOURNAL SERIES C-MECHANICAL SYSTEMS MACHINE ELEMENTS AND MANUFACTURING, vol. 46, no. 3, pp. 848-853.
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Samali, B, Wu, YM & Li, J 2003, 'Shake table tests on a mass eccentric model with base isolation', Earthquake Engineering & Structural Dynamics, vol. 32, no. 9, pp. 1353-1372.
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AbstractA mass eccentric structure is usually more seismically vulnerable than its concentric counterpart because of the coupled torsional–translational response of such structures. In this work, dynamic characteristics and response of a five‐storey benchmark model with moderate mass eccentricity were investigated using a shake table, simulating four different ground motions. The effectiveness of laminated rubber bearings (LRB) and lead‐core rubber bearings (LCRB) in protecting eccentric structures was examined and evaluated in relation to translational and torsional responses of the benchmark model. It was observed that both translational and torsional responses were significantly reduced with the addition of either a LRB or LCRB isolated system regardless of the nature of ground motion input. The LRB were identified to be more effective than LCRB in reducing model relative displacements, the relative torsional angle as well as accelerations, and therefore provided a better protection of the superstructure and its contents. On the other hand, LCRB rendered a smaller torsional angle and absolute displacement of the base isolation system, hence a more stable structural system. Copyright © 2003 John Wiley & Sons, Ltd.
Schäfer, AI, Nghiem, LD & Waite, TD 2003, 'Removal of the Natural Hormone Estrone from Aqueous Solutions Using Nanofiltration and Reverse Osmosis', Environmental Science & Technology, vol. 37, no. 1, pp. 182-188.
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Simon, P, Thomas, PS, Okuliar, J & Ray, AS 2003, 'An incremental integral isoconversional method - Determination of activation parameters', JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY, vol. 72, no. 3, pp. 867-874.
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An incremental integral isoconversional method for the determination of activation energy as a function of the extent of conversion is presented. The method is based on the treatment of experimental data without their transformation so that the resulting values of activation parameters should not be biased. The method was tested for recovering the activation energies from simulated data and employed for the treatment of experimental data of the NiS recrystallisation.
Singh Chaudhary, D, Vigneswaran, S, Hao Ngo, H, Shim, W-G & Moon, H 2003, 'RESEARCH PAPERS : GRANULAR ACTIVATED CARBON (GAC) BIOFILTER FOR LOW STRENGTH WASTEWATER TREATMENT', Environmental Engineering Research, vol. 8, no. 4, pp. 184-192.
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Stewart, MG 2003, 'Cyclone damage and temporal changes to building vulnerability and economic risks for residential construction', Journal of Wind Engineering and Industrial Aerodynamics, vol. 91, no. 5, pp. 671-691.
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A risk analysis procedure is developed to predict economic risks due to changes to existing housing vulnerability over time. The wind hazard and building vulnerability models are based on exposure of residential construction to cyclones in North Queensland, Australia. A feature of the building vulnerability model is that it includes the effect of enhanced (post-1980) building standards in North Queensland. A cyclone damage risk-cost-benefit analysis is then used to assess the economic viability of strengthening existing houses to post-1980 construction quality for temporal changes in economic risks for two scenarios: (i) retrofitting pre-1980 houses to post-1980 quality immediately after they experience cyclone damage, or (ii) rate of growth of the proportion of post-1980 construction. The cost of retrofit or additional cost of strengthened construction can be included in the risk analysis to help assess the economic viability of these and other scenarios. Results are given in terms of annual and annualised economic risks and the damage loss conditional on occurrence of an Average Recurrence Interval event. The annualised economic risk is a time-variant measure of risk that is influenced by temporal changes in building vulnerability, which can be used to help determine the time when a particular strengthening strategy will be economically viable. 'Zones of economic viability' determine the potential for cost-effective retrofitting of residential construction. The risk analysis also enabled the time to economic viability to be calculated. © 2002 Elsevier Science Ltd. All rights reserved.
Stewart, MG & Val, DV 2003, 'Multiple Limit States and Expected Failure Costs for Deteriorating Reinforced Concrete Bridges', Journal of Bridge Engineering, vol. 8, no. 6, pp. 405-415.
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Accurate predictive analyses such as those associated with structural reliability and life-cycle costing are needed for the development of Bridge Management Systems. The present paper presents models for reliability and life-cycle cost analyses of reinforced concrete bridges damaged by corrosion. A stochastic deterioration process for corrosion initiation and propagation and then crack initiation and propagation are used to examine the effect of cracking, spalling, and loss of reinforcement area on structural strength and reliability. This will enable expected costs of failure for serviceability and ultimate strength limit states to be calculated and compared for different repair strategies and inspection intervals. It was found that, for a typical reinforced concrete slab bridge, the reduction of structural capacity at the time of severe cracking or spalling is relatively modest and causes probabilities of collapse conditional on spalling to increase by about an order of magnitude. Hence, expected costs of failure for serviceability were significantly higher than the expected costs of failure for ultimate strength limit states.
Stewart, MG, Rosowsky, DV & Huang, Z 2003, 'Hurricane Risks and Economic Viability of Strengthened Construction', Natural Hazards Review, vol. 4, no. 1, pp. 12-19.
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This paper describes a procedure for evaluating the effect of changes to existing residential structural vulnerability on hurricane-induced building damage and expected insurance losses. Two scenario-based models are proposed for modeling changes in the vulnerability of the existing building stock due to improvements in building envelope performance, for both existing and new residential construction. The influence of changes in structural vulnerability over time on expected insurance losses can then be obtained. The cost of retrofit or additional cost to upgrade new construction can be included in the hurricane damage risk-cost-benefit analysis to assess the economic viability of this and other scenarios. 'Zones of economic viability' are developed that illustrate in a graphical manner whether retrofitting of existing residential construction is cost-effective. For example, in some cases retrofit costs of up to 40% of initial building costs may be economically viable. The risk analysis also enables the time to economic viability to be calculated.
Thomas, PS & Stuart, BH 2003, 'DSC characterisation of compression moulded PEEK-PTFE plaques', JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY, vol. 72, no. 2, pp. 675-679.
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Compression moulded plaques of a range of poly(ether ether ketone) (PEEK)- poly(tetrafluoroethylene) (PTFE) blends (100, 92, 48, 29, 9.5 and 0 mass% PEEK) have been characterised using differential scanning calorimetry (DSC) and wide angle X-ray crystallography (WAXD). A shift in the melting peak of the PEEK phase from 347 to 358°C was observed with increasing proportion of PTFE in the blend. A narrowing of the melting range was also observed. Correspondingly, WAXD measurements showed a reduction in the d-spacings. The observed changes in morphology are rationalised in terms of a higher degree of order imparted on the PEEK crystalline phase by the transmission of an applied 'hydrostatic' pressure by the presence of the PTFE.
Thomas, PS, Hirschausen, D, White, RE, Guerbois, JP & Ray, AS 2003, 'Characterisation of the oxidation products of pyrite by thermogravimetric and evolved gas analysis', JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY, vol. 72, no. 3, pp. 769-776.
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Museum specimens of pyrite are known to undergo oxidation even during storage. Characterisation of the oxidation products is however not always simple due to amorphous character and varying degrees of hydration of the oxidation products, This paper presents an alternative approach to the characterisation of oxidation products by identifying their presence from their characteristic thermal decomposition processes using thermogravimetric and evolved gas analysis. Four pyrite specimens were characterised with varying degrees of oxidation. Iron(II) and iron(III) sulphates were also characterised for comparative purposes. The degradation products were observed to correlate well with the presence of iron(II) sulphate even though there was found to be some discrepancy in the higher temperature decomposition reactions.
Thomas, PS, Simon, P & Ray, AS 2003, 'The effect of thermal history on the morphology of nickel sulphide', JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY, vol. 72, no. 3, pp. 801-809.
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The DSC characterisation of the morphology of the metastable a phase of stoichiometric nickel sulphide was carried out using two calorimeters; a TA Instruments 2920 MDSC and a Perkin Elmer DSC-7, and two quenching histories. Based on these quenching histories, significant differences were observed in the heat flow curves, including the observation of a second exothermic peak which is tentatively assigned to be a metastable phase to metastable phase transformation. The kinetic constants for the a to b recrystallisation were determined as a function of degree of conversion using a mechanism free isoconversional model. Variations in the values of the kinetic constants were also ascribed to the quenching histories. Although the differences in morphology observed were ascribed to the processing history, the shift in the position of the a to b recrystallisation peak was partially attributed to the thermal resistances of the instruments used.
Tian, D, Shon, H-K, Chun, D-J, Jin, C-S, Gwon, E-M & Chung, W-J 2003, 'Isolation and characterization of sulfur-utilizing denitrifiers from the sulfur-oxidizing denitrification process', Biotechnology Letters, vol. 25, no. 19, pp. 1605-1608.
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Val, DV & Stewart, MG 2003, 'Life-cycle cost analysis of reinforced concrete structures in marine environments', Structural Safety, vol. 25, no. 4, pp. 343-362.
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Chloride-induced corrosion of carbon steel reinforcement is the main cause of deterioration of reinforced concrete (RC) structures in marine environments. One of the ways to protect RC structures from corrosion is to use corrosion-resistant stainless steel reinforcing bars. However, stainless steel is between six and nine times more expensive than carbon steel. Thus, its use can only be justified on a life-cycle cost basis. In the paper a time-variant probabilistic model was presented to predict expected costs of repair and replacement which was then used to calculate life-cycle costs for RC structures in marine environments under different exposure conditions. Results of the life-cycle cost analysis can be applied to select optimal strategies improving durability of RC structures in marine environments, including the use of stainless steel reinforcement. © 2003 Elsevier Ltd. All rights reserved.
Vigneswaran, S, Chaudhary, DS, Ngo, HH, Shim, WG & Moon, H 2003, 'Application of a PAC-membrane hybrid system for removal of organics from secondary sewage effluent: Experiments and modelling', SEPARATION SCIENCE AND TECHNOLOGY, vol. 38, no. 10, pp. 2183-2199.
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As world supplies of clean, fresh water come under increasing pressure and the need for water reuse rises, membrane technology is becoming increasingly important as a possible solution. However, membrane fouling is a major obstacle to the successful operation of the membrane process in wastewater treatment. In this study, a submerged hollow-fiber membrane with powdered activated carbon (PAC) adsorption was investigated for the removal of organics from secondary sewage effluent from a sewage treatment plant. The use of PAC in the membrane system was found to be very effective, not only in removing refractory organics, but also in reducing membrane clogging. A simple mathematical model was developed to predict the effluent quality [in terms of total organic carbon (TOC)] of the submerged membrane-adsorption hybrid system.
White, AB, Kumar, P, Saco, PM, Rhoads, BL & Yen, BC 2003, 'CHANGES IN HYDROLOGIC RESPONSE DUE TO STREAM NETWORK EXTENSION VIA LAND DRAINAGE ACTIVITIES1', JAWRA Journal of the American Water Resources Association, vol. 39, no. 6, pp. 1547-1560.
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ABSTRACT: The objective of this work is to determine the effects of extension of a stream network through land drainage activities during the late 1800s on the hydrologic response of a watershed. The Mackinaw River Basin in Central Illinois was chosen as the focus and the pre‐land and post‐land drainage activity hydrologic responses were obtained through convolution of the hill slope and channel responses and compared. The hill slope response was computed using the kinematic wave model and the channel response was determined using the geomorphologic instantaneous unit hydrograph method. Our hypothesis was that the hydrologic response of the basin would exhibit the characteristic effects of settlement (i.e., increases in peak discharges and decreases in times to peak). This, indeed, is what occurred; however, the increase in peak discharges diminishes as scale increases, leaving only the decrease in times to peak. At larger scales, the dispersive effects of the longer hill slope lengths in the pre‐settlement scenario seem to balance the depressive effects of the longer path lengths in the post‐settlement scenario, thus the pre‐settlement and post‐settlement peak discharges are approximately equivalent. At small scales, the dispersion caused by the hill slope is larger in the pre‐settlement case; thus, the post‐settlement peak discharges are greater than the pre‐settlement.
Widjaja, J, Samali, B & Li, J 2003, 'Electrorheological and Magnetorheological Duct Flow in Shear-Flow Mode Using Herschel-Bulkley Constitutive Model', Journal of Engineering Mechanics, vol. 129, no. 12, pp. 1459-1465.
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A quasi-steady duct flow through a parallel plate model for electrorheological (ER) and magnetorheological (MR) fluids under shear-flow mode is investigated mathematically. To do so Herschel-Bulkley power law constitutive model for ER and MR fluid is adopted to account for postyield shear thinning or shear thickening conditions as indicated in recent research. This approach is selected in order to obtain a more flexible representation of ER or MR postyield behavior rather than using the mostly adopted Bingham plastic model. This will lead to developing a theoretical method for prediction of ER or MR force characteristics.
Wu, C, Hao, H & Zhou, Y 2003, 'Distinctive and fuzzy failure probability analysis of an anisotropic rock mass to explosion load', International Journal for Numerical Methods in Engineering, vol. 56, no. 5, pp. 767-786.
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AbstractThis paper estimates failure probability of an anisotropic rock mass with random initial damage and random critical tensile strain to explosion loads. The initial random damage and critical tensile strain of the rock mass are estimated by approximate statistical methods. They are incorporated into the constitutive law of the anisotropic damage model. The statistical estimation of the rock‐mass response to underground explosion is evaluated by the Rosenblueth's point estimate method. A statistical anisotropic continuum damage model considering both the anisotropic initial damage and cumulative damage dependent on tensile strain is suggested. A beta distribution is proposed to represent the probabilistic distribution of the damage variable of the rock mass under blasting loads. Using the theory of reliability, failure probabilities are calculated according to different levels of failure criteria of the rock mass. A fuzzy definition is also proposed to describe the fuzzy nature of failure phenomenon of the rock mass. Based on the fuzzy random probabilistic theory, a model including both the effects of randomness of the rock‐mass properties and fuzziness of its failure criterion is proposed for the failure analysis of the rock mass. The suggested models are coded and linked with an available computer programe Autodyn3D as its user's subroutines. Using the Autodyn3D together with the suggested model, a series of field blasting tests are simulated. Numerical results of stress wave propagation are compared with field‐recorded data. The failure probabilities of the rock mass around the charge hole are estimated. Copyright © 2002 John Wiley & Sons, Ltd.
Wu, C, Hao, H, Lu, Y & Zhou, Y 2003, 'Characteristics of stress waves recorded in small-scale field blast tests on a layered rock–soil site', Géotechnique, vol. 53, no. 6, pp. 587-599.
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A series of field blast tests was carried out in Singapore to study the properties of stress waves inside (free field) and on the surface of a granite site. The stress wave properties inside the granite mass and on the rock surface, such as the peak value and principal frequency, as well as their spatial variations, were reported in a previous paper. Before the blast test, a soil layer of 1·5 m thickness was backfilled and compacted on the quarry test site. Accelerometers were also placed on the surface of the backfilled soil layer, inside the soil mass and on the rock–soil interface. This paper presents the recorded data associated with the backfilled soil layer. The attenuation relations of the peak particle acceleration (PPA), peak particle velocity (PPV) and especially the principal frequency (PF) of the stress wave on the soil surface, inside the soil mass and on the rock–soil surface are derived. They are compared with those recorded inside the granite mass and on the rock surface. Based on the results, the effects of different media on the stress wave propagation are discussed.
Wu, C, Hao, H, Lu, Y & Zhou, Y 2003, 'Characteristics of stress waves recorded in small-scale field blast tests on a layered rock–soil site', Géotechnique, vol. 53, no. 6, pp. 587-599.
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Wu, C, Lu, Y, Hao, H, Lim, WK, Zhou, Y & Seah, CC 2003, 'Characterisation of underground blast-induced ground motions from large-scale field tests', Shock Waves, vol. 13, no. 3, pp. 237-252.
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Wu, CQ, Zhao, LC & Wu, YH 2003, 'Estimation in change-point hazard function models', Statistics & Probability Letters, vol. 63, no. 1, pp. 41-48.
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In this paper, we consider hazard function models with a change-point allowing for random censoring when the base-line hazard function is unknown with some parameters. A non-parametric estimator of the change-point is proposed in the context of counting process. The estimators of change-point and other parameters are shown to be consistent. © 2003 Elsevier Science B.V. All rights reserved.
Wu, J & Amaratunga, K 2003, 'Wavelet triangulated irregular networks', International Journal of Geographical Information Science, vol. 17, no. 3, pp. 273-289.
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Zhang, ZL, Hong, HS, Zhou, JL, Huang, J & Yu, G 2003, 'Fate and assessment of persistent organic pollutants in water and sediment from Minjiang River Estuary, Southeast China', Chemosphere, vol. 52, no. 9, pp. 1423-1430.
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Persistent organochlorine compounds were analyzed in surface water, porewater and surficial sediment samples from Minjiang River Estuary, which is the first large river in Fujian Province, Southeast of China. The total concentrations of 18 organochlorine pesticides were 214.4-1819, 4541-13699 ng/l, 28.79-52.07 ng/g in surface water, porewater and sediments (dry weight) respectively, and those of 21 polychlorinated biphenyls (PCBs) in the three phases were: 203.9-2473, 3192-10855 ng/l, 15.14-57.93 ng/g respectively. The results showed that the concentrations of these selected organochlorine pesticides and PCBs in porewater were higher than those in surface water. It may be due to the fact that these organic hydrophobic pollutants tend to stay in the sediments, and then re-suspend from the sedimentary phase to the upper water. We have analyzed the distribution characteristics of individual organochlorine pesticide components and PCBs, and found that α-HCH, DDE, Heptachlor, Endosulfan II, Methoxychlor were the most common organochlorine pesticides contaminants. Considering the groups of HCHs (HCHs = α-HCH + β-HCH + γ-HCH + δ-HCH) and DDTs (DDTs = DDT + DDD + DDE), the predominance of β-HCH, DDE in all water, porewater and sediment samples was clearly observed. This observation suggested that β-HCH was resistant to biodegradation and the DDTs had been transformed to its metabolites, DDE and DDD, of which DDE that was more undegradable. The PCB congeners containing 3-6 chlorines had the great preponderance in the three phase. These results were compared with those present in other estuaries and harbors. A risk assessment was evaluated for the persistent organic pollutants in the Minjiang River Estuary. © 2003 Published by Elsevier Ltd.
Zhou, JL & Maskaoui, K 2003, 'Distribution of polycyclic aromatic hydrocarbons in water and surface sediments from Daya Bay, China', Environmental Pollution, vol. 121, no. 2, pp. 269-281.
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Marine culture is thriving in China and represents a major component of the regional economy in coastal zones, yet the environmental quality of many of those areas has never been studied. This paper attempts to investigate the quality status of Daya Bay, a key aquaculture area in China. The levels of 16 polycyclic aromatic hydrocarbons (PAHs) were determined in water and sediment samples of the bay. The total concentrations of 16 PAHs varied from 4228 to 29 325 ng l-1 in water, and from 115 to 1134 ng g-1 dry weight in sediments. In comparison to many other marine systems studied, the PAH levels in Daya Bay waters were relatively high, and at six sites they were sufficiently high (>10 μg l-1) to cause acute toxicity. The PAH composition pattern in sediments suggest dominance by medium to high molecular weight compounds, and the ratio of certain related PAHs indicate important pyrolytic and petrogenic sources. Further analysis showed that the distribution coefficient (KD) increased with the particular organic carbon content of sediments, consistent with the PAH partition theory. The organic carbon normalised distribution coefficient (Koc) also increased with the compounds' octanol/water partition coefficient (Kow), confirming the potential applicability of the linear free energy relationships in the modelling and prediction of PAH behaviour in marine environments. © 2002 Elsevier Science Ltd. All rights reserved.
Zhou, JL, Liu, YP & Abrahams, PW 2003, 'Trace metal behaviour in the Conwy estuary, North Wales', Chemosphere, vol. 51, no. 5, pp. 429-440.
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The distribution of trace metals Zn, Ni, Mn, Fe, Cu, Pb, Cd and Cr between suspended particulate matter (SPM) and water in the Conwy estuary, North Wales, has been studied in three surveys in 1998. Dissolved Cu and Mn showed some monthly variations. Most of the dissolved trace metals displayed a negative association with salinity, indicating rivers as a major source of inputs for them. Particulate Zn, Mn and Fe showed a decreasing concentration seaward, whilst the levels of Ni, Cu, Cr and Pb increased with salinity. SPM concentration was the most important variable significantly related to trace metal concentrations in SPM, with an inverse relationship between the two parameters. This was explained by the relative enrichment of trace metals in fine particles at low SPM concentrations and relative depletion of trace metals in coarse particles at high SPM concentrations. Particulate Zn, Mn and Pb were dominated by the fraction available to acetic acid (non-detrital), whilst particulate Ni, Fe and Cr were dominated by the fraction available to nitric acid (detrital). The partition coefficient of trace metals between SPM and water declined with increasing SPM concentration, consistent with the so-called 'particle concentration effect'. Such a phenomenon may be explained by the presence of fine particles (including colloids) enriched with trace metals at low SPM concentrations, and the salinity-induced desorption. © 2002 Elsevier Science Ltd. All rights reserved.
Zhu, XQ & Law, SS 2003, 'Dynamic axle and wheel loads identification: laboratory studies', Journal of Sound and Vibration, vol. 268, no. 5, pp. 855-879.
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Zhu, XQ & Law, SS 2003, 'Dynamic Behavior of Orthotropic Rectangular Plates under Moving Loads', Journal of Engineering Mechanics, vol. 129, no. 1, pp. 79-87.
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ZHU, XQ & LAW, SS 2003, 'IDENTIFICATION OF MOVING INTERACTION FORCES WITH INCOMPLETE VELOCITY INFORMATION', Mechanical Systems and Signal Processing, vol. 17, no. 6, pp. 1349-1366.
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Zhu, XQ & Law, SS 2003, 'Time Domain Identification of Moving Loads on Bridge Deck', Journal of Vibration and Acoustics, vol. 125, no. 2, pp. 187-198.
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A new time domain method is presented to identify moving loads on a bridge deck based on the measured responses. The bridge deck is modeled as an orthotropic plate and the loads are modeled as a group of four loads moving on top of the bridge deck at fixed distance apart. Dynamic behavior of the bridge deck is analyzed by the orthotropic plate theory and mode superposition technique. Like all inverse problems, this identification is an ill-conditioned problem, and a regularization technique is employed to stabilize the computations. The identified loads moving at different eccentricities are presented. Laboratory work on the force identification is also presented. The effect of incomplete measured modes in the responses is discussed, and an underestimation in the loads may result if the number of vibration mode for identification is larger than that in the responses. Computational simulations and laboratory tests show that the method is effective and practical for identification of individual wheel loads on bridge decks.
Chaudhary, DS, Guo, W, Vigneswaran, S, Ngo, H & Vigneswaran, B 1970, 'Submerged Microfiltration: An Energy Efficient Process for Water Reuse', AWA Oz Water Convention and Conference, Australian Water Association Convention - Ozwater, AWA, Perth, Australia, pp. 1-9.
Collings, G & Ball, JE 1970, 'The Hydrological Effects of the January 94 Bush Fires on the Royal National Park', Proc. 28th International Hydrology and Water Resources Symposium, Hydrology and Water Resources Symposium, The Institution of Engineers, Australia, Wollongong, NSW, Australia, pp. 161-168.
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Previous research into the hydrological effects of fire have found that runoff increases immediately after the fire. This was attributed to the removal of vegetation and a decrease in the initial losses associated with rainfall. Another possible cause for the increase in runoff is heat treating of. the soil as the fire scorches the soil and there is a resultant decrease in the ability of the water to infiltrate. After this initial period of increased runoff, the conversion of rainfall to runoff has been reported to decrease. This decrease in runoff has been attributed to increases in the evapo-transpiration losses of the forest. In January 1994, Sydney was surrounded by a number of wild fires. The Royal National Park which is located to the south of Sydney is one of the areas burnt by these bush fires. For a number of years, SCEE UNSW has operated and maintained a network of pluviometers and stream flow gauges within the Upper Hacking Catchment, which lies within the Royal National Park. During the January 1994 bush fires approx 30% - 40% of the monitored catchment was burnt. Analysis of pre and post fire daily totals was undertaken for the catchment to assess the impact of the fire. Excessive change in the rainfall-runoff relationship of the catchment determined through the lnltlal.analysls lead to the investigation of other parameters affecting the hydrology. It was shown that changes in the rainfall-runoff relationships due to the fire are interrelated to the changes in the rainfall-runoff relationship due to the onset of drought. Furthermore, it was shown through investigation of two catchments that changes in the rainfall-runoff relationships in both catchments were similar. Consequently, it was concluded that for the Royal National Park, the impacts of bush fires on the rainfall-runoff relationship are interrelated to the impacts of the drought on the rainfall-runoff relationship.
Crews, K 1970, 'An Overview of the Development of Stress Laminated Cellular Timber Bridge Decks for Short to Medium Span Applications in Australia', High Performance Materials in Bridges, International Conference on High Performance Materials in Bridges, American Society of Civil Engineers, pp. 162-172.
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Stress laminated timber bridge deck technology has been established in Australia since 1991, resulting in the construction of over 40 prototype bridges. This paper presents an overview of the R&D undertaken to implement this technology, involving laboratory testing and field application of plate decks spanning up to 9m and high capacity cellular decks spanning 12m, with the potential to span up to 30m.
Guo, W, Vigneswaran, S, Ngo, H & Ben Aim, RM 1970, 'Evaluating the Efficiency of Pretreatment to Microfiltration: Using Critical Flux As a Performance Indicator', IMSTEC 2003, International Membrance Science and Technology Conference, AWA-UNESCO Membrane Centre, Sydney, Australia, pp. 1-6.
Guo, W, Vigneswaran, S, Ngo, H, Shon, H & Shimohoki, S 1970, 'Improving the Performance of a Crossflow Microfiltration in Tertiary Wastewater Treatment and Reuse By Specific Pre-Treatment Processes', ASIAN WaterQual 2003, IWA Asia-Pacific Regional Conference, IWA-Regional Publication, Bangkok, Thailand, pp. 1-8.
Haque, A & Indraratna, B 1970, 'Effect of roughness on the peak shear strength of clay infilled joints under constant normal stiffness', 10th ISRM Congress, pp. 481-485.
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The shear behaviour of infilled joints produced from ordinary gypsum plaster (gyprock) and bentonite was investigated in the laboratory under Constant Normal Stiffness (CNS) conditions. Shear tests were performed on saw-tooth profiles having Joint Roughness Coefficients (JRC) of 4.75 and 9.25 under an initial normal stress (sno) of 0.30 to 1.10 MPa, and at a normal stiffness (kn) of 8.5 kN/mm. Test data under the same sno and infill thickness to asperity height ratio (t/a) were analysed for two different sets of JRC. The peak shear stress plotted against the t/a ratio under constant sno revealed an increase in peak shear stress with the increase in JRC, up to a t/a ratio of about unity. The effect of roughness on the peak shear stress was observed to be minimal when the t/a ratio exceeded 1.40. A mathematical model for the prediction of peak shear stress due to the increased infill thickness has been developed based on a hyperbolic stress-strain relationship and energy balance principles. The model predictions are in good agreement with the laboratory observations.
Indraratna, B & Salim, W 1970, 'Deformation and Degradation Mechanics of Recycled Ballast Stabilised with Geosynthetics', Soils and Foundations, 3rd International Symposium on Deformation Characteristics of Geomaterials, Elsevier BV, LYON, FRANCE, pp. 35-46.
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Janotka, I, Ray, AS & Samarin, A 1970, 'Zeolite blended cement for better sulphate resistance', Proceedings of the 21st Biennial Conference of the Concrete Institute of Australia 2003, Biennial Conference of the Concrete Institute of Australia, Concrete Institute of Australia, Brisbane, Australia, pp. 233-241.
Kim, D, Shon, H, Vigneswaran, S & Cho, J 1970, 'Evaluating Interactions Between NOM Molecules and Various Membranes with Flow Field -Flow Fractionation', IMSTEC 2003, Fifth International Membrane Science and Technology Conference, AWA-UNESCO Membrane Centre, Sydney, Australia, pp. 1-6.
Li, J, Samali, B & Crews, KI 1970, 'Determining Individual Member Stiffness of Bridge Structure Using a Simple Dynamic Procedure', Proceedings of the 10th Asia Pacific Vibration Conference, Asia Pacific Vibration Conference, Queensland University of Technology, Gold Coast, Queensland, Australia, pp. 379-384.
Loganathan, P, Hedley, MJ, Grace, ND, Lee, J, Cronin, SJ, Bolan, NS & Zanders, JM 1970, 'Fertiliser contaminants in New Zealand grazed pasture with special reference to cadmium and fluorine: a review', AUSTRALIAN JOURNAL OF SOIL RESEARCH, pp. 501-532.
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Phosphorus (P) fertilisers are an essential input for the economic production of legume-based pastures in New Zealand (NZ) and Australia, but they often contain some unwanted elements that can contaminate the soil, thereby creating potential risks to the health of grazing animal, food quality, and soil quality. Fluorine (F) and cadmium (Cd) are considered to be the elements of most concern. Incidences of F toxicity (from direct ingestion of fertiliser), and accumulation of Cd in offal products above the maximum permissible concentration (MPC) set by the food authorities, have been reported in NZ. Similarly, Cd concentrations in some food grains may exceed the newly proposed MPCs by the Australian and New Zealand Food Authority. Cadmium and F continue to accumulate in the topsoils of NZ and Australian pastures as a result of P fertiliser use. The mobility of both these elements in soils is low and is similar to that of P. Risk of ground water contamination from F and Cd applied to most NZ pastures is low. The plant uptake of these elements, especially F, is also low in most pastoral soils. Cadmium accumulates mainly in liver and kidney of grazing animals mostly through herbage ingestion, whereas F accumulates mainly in the bones of these animals, mostly through soil ingestion. Soil ingestion is highest during the wetter winter months and at high stocking rates. Models have been developed to assess the impact of fertiliser use on the potential risks associated with F and Cd accumulation in soils. Measures to control F and Cd accumulation in soils, plants, and grazing animals are presented and future research needs are identified.
Maheswaran, SM, Yadav, NN, Shutthanandan, V, Thevuthasan, S, Hart, TR, Ngo, H & Vigneswaran, S 1970, 'Evaluating the use of induced X-ray emission (PIXE) technique in quantifying the arsenic in an adsorbent', ASIAN WaterQual2003, IWA Asia-Pacific Regional Conference, IWA-regional publication, Bangkok, Thailand, pp. 1-8.
Mayol, E, Samali, B, Kwok, KC & Li, J 1970, 'Vibration Control of An Experimental Benchmark Model To Earthquake Using Liquid Column Vibration Absorbers (LCVAs)', Proceedings of the 10th Asia Pacific Vibration Conference, Asia Pacific Vibration Conference, Queensland University of Technology, Gold Coast, Queensland, Australia, pp. 451-456.
McLean, JT, Beecham, SC & Kandasamy, JK 1970, 'Field Assessment of Local Scour at Bridge Sites', 28th International Hydrology and Water Resources Symposium, Hydrology and Water Resources Symposium, Engineers Australia, Wollongong, Australia, pp. 1-8.
Nejadi, S & Gilbert, RI 1970, 'Shrinkage cracking in restrained reinforced concrete members', ADVANCES IN STRUCTURES, VOLS 1 AND 2, International Conference on Advances in Structures, A.A. Balkema, Swets & Zeitlinger B.V. Lissie, The Netherlands, Sydney, Australia, pp. 1065-1071.
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The problem of cracking caused by shrinkage in restrained reinforced concrete members is discussed and examined both experimentally and analytically. A total of eight fully restrained slab specimens with different reinforcement layouts were monitored for up to 150 days to measure the effects of drying 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. The effects of varying the quantity of reinforcing steel, the bar diameter and the bar spacing were studied in order to gain a clearer understanding of the mechanisms of direct tension cracking caused by restrained shrinkage and the factors affecting it. An analytical model developed previously to study the problem (Gilbert, 1992) is also described and the experimental results and analytical predictions are compared.
Samali, B, Bakoss, SL, Li, J, Saleh, A & Wije, A 1970, 'Assessing the Structural Adequacy of a 3-span Steel-Concrete Bridge Using Dynamic Methods: A case study', Abstracts of the Tenth International Conference: Structural Faults & Repair Abstracts, ENGINEERING TECHNICS PRESS, London, UK.
Samali, B, Djajakesukma, S, Nguyen, HT & Li, J 1970, 'An Experimental Study of a Five Storey Steel Frame Using Semi-active Control System', Proceedings of the 10th Asia Pacific Vibration Conference, Asia Pacific Vibration Conference, Queensland University of Technology, Gold Coast, Queensland, Australia, pp. 604-609.
Samali, B, Widjaja, JH, Li, J & Reizes, J 1970, 'Magneto-rheological Shear Dampers; Quasi-static Modelling and Simulation', Proceedings of the 10th Asia Pacific Vibration Conference, Asia Pacific Vibration Conference, Queensland University of Technology, Gold Coast, Queensland, Australia, pp. 1-6.
Shackel, B, Ball, JE & Mearing, M 1970, 'Using permeable eco-paving to achieve improved water quality for urban pavements', Proceedings of the 7th International Conference on Concrete Block Paving, PAVE AFRICA 2003, Document Transformation Technologies, South Africa, pp. 1-11.
Shon, H, Vigneswaran, S, Ngo, H & Ben Aim, RM 1970, 'Low Pressure Nanofiltration with Adsorption As Pretreatment In Tertiary Wastewater Treatment for Reuse', IMSTEC 2003, International Membrane Science and Technology Conference, AWA-UNESCO Membrane Centre, Sydney, Australia, pp. 1-7.
Shon, H, Vigneswaran, S, Ngo, H & Kim, IS 1970, 'Effect of high rate Pre-Treatment on Nanofiltration Systems in Wastewater Reuse', ASIAN WaterQual 2003, IWA Asia-Pacific Regional Conference, IWA-Regional Publication, Bangkok, Thailand, pp. 1-9.
Shon, H, Vigneswaran, S, Ngo, H, Kim, D, Park, NE, Jang, NJ & Kim, IS 1970, 'Characterisation of Effluent Organic Matter (EFOM)Of Fouled Nanofilter (NF) Membranes', IMSTEC2003, Fifth International Membrane Science and Technology Conference, AWA-UNESCO Membrane Centre, Sydney, Australia, pp. 1-6.
Stewart, MG, Faber, MH & Gehlen, C 1970, 'Temporal and Spatial Aspects of Probabilistic Corrosion Models', Life-Cycle Performance of Deteriorating Structures, Third IABMAS Workshop on Life-Cycle Cost Analysis and Design of Civil Infrastructures Systems, American Society of Civil Engineers, pp. 183-193.
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The paper initially reviews sources of structural deterioration, with emphasis on chloride-induced corrosion of reinforced concrete structures. Thereafter, a critical review of deterioration models for corrosion initiation and propagation and their effect on structural performance is given. It is observed that many probabilistic deterioration models exist and that they can produce somewhat divergent predictions of corrosion initiation and propagation. The paper also examines the high temporal and spatial uncertainty and variability of existing deterioration models and the impact this might have on decision-making criteria. Finally a discussion is given in regard to how to proceed in future research and development with the aim of establishing a consistent and operational model basis for the design, assessment, inspection and maintenance of concrete structures.
Trolove, SN, Hedley, MJ, Kirk, GJD, Bolan, NS & Loganathan, P 1970, 'Progress in selected areas of rhizosphere research on P acquisition', AUSTRALIAN JOURNAL OF SOIL RESEARCH, pp. 471-499.
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Large reserves of P have accumulated in soils of developed countries because additions of P fertiliser to sustain agricultural production have exceeded crop removal. By contrast, in many developing countries in the tropics and subtropics, soil P reserves are gravely low and large additions are required before maintenance requirements begin to decline. In addition, the cost of P fertiliser will increase as the currently accessible deposits of high-grade phosphate rock (PR) diminish. Developing plants that efficiently tap soil P reserves and low grade PR is therefore a priority for agricultural research. For the 50th anniversary of the New Zealand Soil Science Society, this paper reviews research on P efficiency in plants, conducted by staff, students, and research associates of Massey University, in the context of other research into plant mechanisms that enhance P uptake, including effects of root geometry, mycorrhizal associations, and root-induced changes in the soil. Techniques for fractionation of soil P are highlighted.
Umakhanthan, K, Ball, JE & MSSANZI 1970, 'The importance of rainfall models in catchment simulation', MODSIM 2003: INTERNATIONAL CONGRESS ON MODELLING AND SIMULATION, VOLS 1-4, International Congress on Modelling and Simulation, UNIV WESTERN AUSTRALIA, Townsville, AUSTRALIA, pp. 368-373.
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Catchment management is a complex task that, over the past decade, has become increasingly important to the community. Information for this management increasingly is being obtained from implementation ofcatchmentmodellingsystems. Implementation ofa catchmentmodelling systemrequiresthree steps,whichare the calibrationofthe system, the validationofthe calibration, andthe extrapolation ofthe system to different hydrologic events and catchment conditions. The robustness of the simulations when this extrapolation is undertaken is relatedto the calibrationandvalidationof the catchmentmodellingsystem,which inturn are impactedbythe qualityandreliabilityofthe inputdata. Acatchment modellingsystemfor simulation of catchment processes can be considered to consist of four conceptual components. Within each of these components, there are manyalternativetransformations availablewith each of these transformations beingthe resultof differentcombinations of processmodels. Theconceptof systemcalibrationis to selectthe appropriate transformations andinputinformation that best represents the catchment beingsimulated. Withinthe generation componentan importantaspect is the model used to transformthe point rainfallmeasurements into a spatially distributed rainfall-over the catchment. There have been many alternative models proposed for this transformation. Presentedherein is an analysisof the influence of alternative rainfall models on the simulated hydrographandhencethe influenceonthe systemcalibration. This analysis willbebasedonreal eventsrecorded at the outletsof the Centennial Park catchment(LBkrrr') andthe UpperParramattaRiver catchment(110km2 ) in Sydney, Australia. It wasfoundthat an increaseinthe robustness ofthe predictions obtainedwasrelateddirectly to the storm variability as definedby the spatial and temporal semi-variograms developed duringthe study.
Val, DV & Stewart, MG 1970, 'Evaluation of Expected Utility for Decision Analysis of Structures', Life-Cycle Performance of Deteriorating Structures, Third IABMAS Workshop on Life-Cycle Cost Analysis and Design of Civil Infrastructures Systems, American Society of Civil Engineers, pp. 413-423.
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In order to make a rational decision about a cost-effective solution the life-cycle cost of a structure including cost of structural failure needs to be considered. Due to uncertainties associated with structural properties, loads and environmental conditions the cost of structural failure is a random variable. The paper derives probability distributions of the cost of failure of a single structure and a group of identical structures when single or multiple failures are possible during the service life of a structure. The probability distributions are based on cumulative probabilities of failure of a single structure over its service life. The probability distributions can be employed to evaluate the expected utility, which is then used in decision making. An example, which considers the selection of durability specifications for a reinforced concrete structure built in marine environments, illustrates the use of the derived probability distributions.
Wu, Y, Samali, B & Li, J 1970, 'Seismic Response of Torsionally Sensitive Building Models', Proceedings of the 10th Asia Pacific Vibration Conference, Asia Pacific Vibration Conference, Queensland University of Technology, Gold Coast, Queensland, Australia, pp. 765-770.
