Ahmed, BYM 1997, 'Climatic classification of Saudi Arabia: An application of factor-cluster analysis', GeoJournal, vol. 41, no. 1, pp. 69-84.
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This study is aimed to be a contribution to climatic regionalization of Saudi Arabia. The study applies a multivariate factor-cluster analysis technique. The data used here have been obtained from 56 meteorological stations. The application of the technique is made into two stages. In the first stage, factor analysis alone is considered and its results in Saudi Arabia are discussed. In the second stage, the resultant factor scores are taken as an input in a cluster analysis process to obtain climatic regions. Thus the regions obtained in the second stage are a result of the integration of factor and cluster techniques. The results obtained by the technique are compared with those of some traditional methods. The factor-cluster analysis technique is found advantageous over many of those methods, as it produces richer regions and shows clear climate variations within this vast country.
Indraratna, B 1997, 'Interpretation of field and laboratory shear strength data of a soft marine clay', Quarterly Journal of Engineering Geology, vol. 30, no. 3, pp. 197-203.
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Soft Muar Clay in Malaysia is of marine origin, and is characterized by a high water content that is close to or greater than its liquid limit. The variation of in situ vane shear strength is compared with various undrained laboratory tests conducted on undisturbed specimens recovered from different depths. The effects of the overburden pressure and Atterberg limits on the vane shear strength are discussed. Correlations between the field vane shear strength and the cone penetration resistance are also determined, and the effect of plasticity index on the normalized cone resistance is discussed. The results obtained for the Muar Clay are compared with other available data for selected soft marine clays. The use of the corrected and uncorrected vane strengths in the prediction of slip surface is also discussed. © 1997 The Geological Society.
Indraratna, B & Haque, A 1997, 'Experimental study of shear behavior of rock joints under constant normal stiffness conditions', International Journal of Rock Mechanics and Mining Sciences, vol. 34, no. 3-4, pp. 141.e1-141.e14.
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Indraratna, B & Redana, IW 1997, 'Plane-Strain Modeling of Smear Effects Associated with Vertical Drains', Journal of Geotechnical and Geoenvironmental Engineering, vol. 123, no. 5, pp. 474-478.
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Indraratna, B & Vafai, F 1997, 'Analytical Model for Particle Migration within Base Soil-Filter System', Journal of Geotechnical and Geoenvironmental Engineering, vol. 123, no. 2, pp. 100-109.
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Indraratna, B, Balasubramaniam, AS & Sivaneswaran, N 1997, 'Analysis of settlement and lateral deformation of soft clay foundation beneath two full-scale embankments', International Journal for Numerical and Analytical Methods in Geomechanics, vol. 21, no. 9, pp. 599-618.
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Keshavarzy, A & Ball, JE 1997, 'Analysis of the characteristics of rough bed turbulent shear stresses in an open channel', STOCHASTIC HYDROLOGY AND HYDRAULICS, vol. 11, no. 3, pp. 193-210.
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Khatri, RP & Sirivivatnanon, V 1997, 'Methods for the determination of water permeability of concrete', ACI MATERIALS JOURNAL, vol. 94, no. 3, pp. 257-261.
Khatri, RP, Sirivivatnanon, V & Yang, JL 1997, 'Role of permeability in sulphate attack', CEMENT AND CONCRETE RESEARCH, vol. 27, no. 8, pp. 1179-1189.
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Khatri, RP, Sirivivatnanon, V & Yu, LK 1997, 'Effect of curing on water permeability of concretes prepared with normal Portland cement and with slag and silica fume', MAGAZINE OF CONCRETE RESEARCH, vol. 49, no. 180, pp. 167-172.
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Kwon, DY, Vigneswaran, S, Ngo, HH & Shin, HS 1997, 'An enhancement of critical flux in crossflow microfiltration with a pretreatment of floating medium flocculator/prefilter', WATER SCIENCE AND TECHNOLOGY, vol. 36, no. 12, pp. 267-274.
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In this study, use of a combined system of flocculation-microfiltration was assessed for its capability in removing solids and organics. The improvement of flux by the preflocculation was also investigated. The experimental set-up consisted of (i) Millipore flat plate microfiltration module with constant permeate withdrawal arrangement and (ii) a floating medium flocculator/filter consisting of polypropylene beads as a pretreatment. Commercial ferric chloride(FeCl3) was used for flocculation. The purpose of floating medium filter was primarily to produce filterable flocs and also to achieve partial solids and organics removal. The critical flux of kaolin clay suspension of 10 - 100mg/L was measured for membrane of pore size of 0.2m in the presence of 0 - 4mg/L of fulvic acid in the suspension without any pretreatment. The critical flux was found to decrease with the increase in kaolin clay concentration. The results also indicated that there was no significant effect of organic (fulvic acid) concentration on critical flux. The pretreatment of floating medium filter alone without flocculant addition removed 30 - 40% of solids and resulted in a significant improvement of critical flux in crossflow microfiltration. Degree of solids and organic removal and the variation in critical flux were then studied in detail for the preflocculated/filtered kaolin clay suspension in the presence of organics. The pretreatment of flocculation/prefiltration removed approximately 50% of organics while producing uniform microflocs of 13 - 16 m size. In addition, it enhanced the critical flux by 70% and resulted in 30 - 70% of the remaining organic removal in the crossflow microfiltration.
Loganathan, P & Hedley, MJ 1997, 'Downward movement of cadmium and phosphorus from phosphatic fertilisers in a pasture soil in New Zealand', ENVIRONMENTAL POLLUTION, vol. 95, no. 3, pp. 319-324.
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Total cadmium (Cd) and phosphorus (P) concentrations in a pastoral soil, amended annually for 10 years with four forms of P fertilisers, decreased with soil depth. Single superphosphate (SSP) and North Carolina phosphate rock (NCPR) which had higher Cd contents (32 and 41 mg kg-1, respectively) produced higher total soil Cd than diammonium phosphate (DAP - 10 mg kg-1), Jordan phosphate rock (JPR - 5 mg kg-1) and control treatments to a depth of 120 mm. Total soil P in SSP treated plots to a depth of 120 mm and NCPR treated plots to a depth of 75 mm was also higher than the control plots. No significant fertiliser P and Cd moved below 120 mm depth. Approximately 90% of the applied Cd was recovered in the soil of which 93% remained within the top 120 mm. Plant recovery of applied Cd was 1.5-4.5%. Plant available P (Olsen P) also decreased with depth. Plant available Cd (0.01 M CaCl2 extractable Cd) was higher in the 30-75 and 75-120 mm soil depths compared to 0-30 mm soil depth. This may be die to strong adsorption of Cd by the surface soils which have a higher organic matter content and higher pH; factors which are known to increase Cd adsorption in soils.
Smallwood, AG, Thomas, PS & Ray, AS 1997, 'Characterisation of sedimentary opals by Fourier transform Raman spectroscopy', SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY, vol. 53, no. 13, pp. 2341-2345.
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The Fourier transform Raman (FT-Raman) spectra of a series of opals are presented. The opals characterised derive from a variety of origins in Australia and they are compared to opals originating from North America. The opals are distinguished by their c
Stewart, MG 1997, 'Concreting workmanship and its influence on serviceability reliability', ACI Materials Journal, vol. 94, no. 6, pp. 501-509.
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A serviceability reliability model is used herein to calculate probabilities of serviceability failure for reinforced concrete beams. Results are reported herein of a survey investigating the percentage of construction sites that exhibit poor, fair or good levels of workmanship for concreting tasks that influence concrete compressive strength; namely, compaction and curing. Using this information, probabilistic models have been developed to describe the influence that these tasts have on concrete compressive and tensile strengths. These material property models are included in the serviceability reliability model. It was found that poor concreting workmanship reduced serviceability reliability by more than an order of magnitude, and that inadequate curing is more detrimental to serviceability performance than inadequate compaction. The incorporation of element dimension and reinforcement placement errors into the analysis had little influence on serviceability reliabilities.
Stewart, MG 1997, 'Time-Dependent Reliability of Existing RC Structures', Journal of Structural Engineering, vol. 123, no. 7, pp. 896-902.
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The conditional probability of failure of a structure, given that it has already survived for T years, shows that structural reliability increases for service proven structures. Further, construction loads act essentially as proof loads, and so provide a means to detect the presence of gross construction errors. The present paper investigates the effect of construction error, proof load tests prior to occupation, realistic construction loads, and dead loads and office floor live loads on the probability of failure of service proven structures. The human reliability analysis (HRA) approach is used to simulate the effects of construction error. Results obtained from a Monte-Carlo computer simulation analysis showed that up to 50% of failures will occur during construction for reinforced-concrete beams constructed without engineering inspections. This suggests that construction loads act essentially as proof loads; hence, for structures with low live-to-dead load ratios the adverse consequences of construction error will most likely become evident during construction. Nevertheless, engineering inspections is a more effective error control measure.
Thomas, PS & Stuart, BH 1997, 'A Fourier transform Raman spectroscopy study of water sorption by poly(vinyl alcohol)', SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY, vol. 53, no. 13, pp. 2275-2278.
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The Fourier transform (FT) Raman spectrum of poly(vinyl alcohol) (PVA1) is reported. The spectra of PVA1 exposed to different aqueous environments are also reported. The changes to the FT Raman spectrum of PVA1 in the presence of water provide evidence o
Zhou, JL & Rowland, SJ 1997, 'Evaluation of the interactions between hydrophobic organic pollutants and suspended particles in estuarine waters', Water Research, vol. 31, no. 7, pp. 1708-1718.
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Zhou, JL, Rowland, SJ, Fauzi, R, Mantoura, C & Lane, MCG 1997, 'Desorption of tefluthrin insecticide from soil in simulated rainfall runoff systems—Kinetic studies and modelling', Water Research, vol. 31, no. 1, pp. 75-84.
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Zoysa, AKN, Loganathan, P & Hedley, MJ 1997, 'A technique for studying rhizosphere processes in tree crops: Soil phosphorus depletion around camellia (Camellia japonica L) roots', PLANT AND SOIL, vol. 190, no. 2, pp. 253-265.
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Rhizosphere studies on tree crops have been hampered by the lack of a satisfactory method of sampling soils at various distances in the rhizosphere. A modified root study container (RSC) technique developed for annual crops, grasses and legumes was used to study the mechanisms by which camellia plants (Camellia japonica L.) utilise soil P in the glasshouse and field. Plants belonging to the Camellia family (e.g. tea) have the ability to utilise P from relatively unavailable native P sources and for this reason camellia plants were selected for this study. In the glasshouse trial, the RSCs were filled with a Recent soil, treated with P fertilisers; North Carolina phosphate rock (NCPR), diammonium phosphate (DAP), mono calcium phosphate (MCP) and single superphosphate (SSP) at 200 μg Pg-1 soil. A planar mat of roots was physically separated by a 24 μm polyester mesh and the soil on the other side of this mesh was cut into thin slices parallel to the rhizoplane and analysed for pH, and different forms of P (organic, P(o) and inorganic, P(i)) to understand P depletion at different distances from camellia roots. In the field trial this technique was modified and used to study the rhizosphere processes in mature camellia trees fertilised with only SSP and NCPR. In both field and glasshouse trials, all P fertilisers increased all the bulk soil P fractions except NaOH-P(o) over unfertilised soil with the greatest increases being in the H2SO4-P(i) fraction in the NCPR treatment and NaOH-P(i) in the SSP treatment. Resin-P, NaOH-P(i) and H2SO4-P(i), were significantly lower in the rhizosphere soil compared to the bulk soil whereas NaOH-P(o) was higher in the rhizosphere soil than in the bulk soil. Plant and microbial P uptake were thought to be the major causes for the low resin-P rather than P fixation by Fe and Al because the NaOH-P(i) fraction which is a measure of Fe-P and Al-P, also decreased in the rhizosphere soil. The rhizo-deposition of NaOH-P(o) suggests that labi...
Baweja, D, Roper, H & Sirivivatnanon, V 1970, 'Quantitative descriptions of steel corrosion in concrete using resistivity and anodic polarism data', American Concrete Institute, ACI Special Publication, pp. 41-63.
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This paper presents results from a major long-term study on chloride induced steel corrosion in concrete. Specifically, data on concrete resistivity and estimated corrosion rates of steel in concrete have been measured and compared. The performance of 50 reinforced concrete slabs made with a range of portland and blended cement binders was evaluated. A high C3A cement, a low C3A cement a blended fly ash cement and a blended blast furnace slag cement were used. All reinforced concrete slabs were exposed to high chloride conditions by partial immersion in simulated sea water conditions. Reinforcement was cleaned and weighed prior to embedment into the concrete slabs. Periodic non-destructive measurements of concrete performance included half cell potential monitoring, concrete resistivity and electrochemical measurements of rates of corrosion of steel in concrete using potentiodynamic anodic procedures. In addition, individual slabs were broken for reinforcement recovery at predetermined times during the study and measurements made of the area of corrosion and the weight loss of steel through corrosion. As opposed to the initiation-propagation model frequently cited in the literature, three distinct segments were apparent when the estimated corrosion current data were plotted against the concrete resistivity over a period of five years for reinforced concrete slabs considered in this study. The first stage was described as the Quiescent Stage, during which it was found that resistivity increased with time and estimated corrosion current values were low. Upon reaching a maximum resistivity value, a second stage of corrosion took place. This stage was described as the Active Stage, during which resistivity values decreased and estimated corrosion current values increased. After this, a third or Breakaway Stage of corrosion was reached, during which resistivity values decreased at a lower rate while estimated corrosion currents increased significantly. The f...
Dharmappa, HB, Hasia, A & Hagare, P 1970, 'Water treatment plant residuals management', WATER SCIENCE AND TECHNOLOGY, Asian Waterqual 95: The 5th IAWQ Asian Regional Conference on Water Quality and Pollution Control, PERGAMON-ELSEVIER SCIENCE LTD, MANILA, PHILIPPINES, pp. 45-56.
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Sirivivatnanon, V & Kidav, EU 1970, 'Fly ash concretes in South-East Asia and Austrailia', American Concrete Institute, ACI Special Publication, pp. 123-139.
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This paper outlines the historical developments in the use of fly ash in Australia, Malaysia and Thailand. The slow but marked change in the philosophical approach to the use of fly ash concretes is discussed. With more focused research into the durability performance of fly ash concretes for specific environments in Malaysia and Australia, fly ash concretes in both countries are gaining acceptance into this new area of applications. This is also reflected in some of the most advanced specifications. It has been found that for concretes of equal 28-day strength, the use of fly ash in concretes resulted in a better resistance to chloride ingress. This was also shown in the lower coulomb values in the ASTM C 1202. Higher strength grade portland and fly ash concretes gave lower coulomb values. Other related work had shown that the use of fly ash could result in a lower corrosion rate of steel reinforcement in concretes. Hence a significantly longer service life could be expected from t1y ash concretes compared with portland cement concretes of equal strength. In high-performance concretes, it has been found that the use of triple blends of either a slag or a silica fume added to the fly ash/portland cement system could further enhance the chloride resistance of the concretes.
