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.
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.
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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Ha, QP, Trinh, H, Nguyen, HT & Tuan, HD 2003, 'Dynamic output feedback sliding-mode control using pole placement and linear functional observers', IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS, vol. 50, no. 5, pp. 1030-1037.
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This paper presents a methodological approach to design dynamic output feedback sliding-mode control for a class of uncertain dynamical systems. The control action consists of the equivalent control and robust control components. The design of the equivalent control and the sliding function are based on the pole-placement technique. Linear functional observers are developed to implement the sliding function and the equivalent control. Stability of the resulting system under the proposed control scheme is guaranteed. A numerical example is given to demonstrate its efficacy.
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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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.
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.
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.
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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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, 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.
Baweja, D, Cao, T & Bucea, L 1970, 'Investigation of Dispersion Levels of Silica Fume in Pastes, Mortars, and Concrete', American Concrete Institute, ACI Special Publication, pp. 1019-1034.
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A significant amount of work has been carried out on silica fume and its use in concrete, both from a research and a field perspective, over the last 30 years. There is currently, however, a major debate on silica fume dispersion in concrete and the impact of undispersed silica fume on short and long-term concrete properties. Some suggest that complete dispersion of silica fume can be achieved in concrete through appropriate mixing strategies. Others disagree, suggesting that there are high probabilities of formation of silica fume agglomerates in concrete. Th'e latter further suggest that late-reaction between silica fume agglomerates and the lime within the concrete matrix can potentially induce microcracking, and durability and serviceability problems in concrete elements. This paper presents results, obtained from an investigation into the use of silica fume in concrete. The work considered scanning electron microscope data on samples obtained in laboratory studies and in field concretes. Three silica fumes were investigated in pastes and mortars at a series of dose rates and used in conjunction with different superplasticisers. Investigations were also conducted on concretes from samples taken from actual structural elements. Typical 28-day compressive strengths for this concrete were 55 MPa. Examination of hardened silica fume pastes revealed a large number of agglomerates. Increased mixing time did not significantly influence the presence of such agglomerates, although the use of superplasticisers appeared to marginally reduce agglomerate occurrence. In hardened mortars, silica fume agglomerates were again observed. Mixing time and superplasticiser dosage were found to influence agglomerate occurrence. In concrete, agglomerate occurrence was significantly reduced when compared with that found in the pastes and mortars. Although silica fume agglomerates were found in concrete samples, shear action of aggregate during mixing reduced silica fume agglomerate n...
Boardman, G, Zhu, J & Ha, QP 1970, 'Dynamic and Steady State Modelling of the Doubly Fed Twin Stator Induction Generator with Core Loss', International Conference on Renewable Energy and Power Quality, International Conference on Renewable Energy and Power Quality, European Assoc for the Development of Renewable Energy, Enviro and Power Qlty and Uni of Vigo, Spain, Vigo, Spain, pp. 332-339.
Boardman, G, Zhu, J & Ha, QP 1970, 'Synchronous Drive Performance of the Brushless Doubly Fed Induction Machine', Australasian Universities Power Engineering Conference, Australasian Universities Power Engineering Conference, University of Canterbury, New Zealand, Christchurch, New Zealand, pp. 30-35.
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.
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.
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.
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.
Nguyen, V, Ha, QP & Nguyen, HT 1970, 'A Chattering-Free Variable Structure Controller for Tracking of Robotic Manipulators', Proceedings of The Australian Conference on Robotics and Automation (ACRA 2003), Australasian Conference on Robotics and Automation, ARAA Australian Robotics and Automation Association, Brisbane, Australia, pp. 1-6.
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.
Sri Ravindrarajah, R 1970, 'The bleeding of fresh concrete containing cement supplementary materials', The 9th east asia-pacific conference on structural engineering and construction proceedings, East Asia-Pacific Conference on Structural Engineering and Construction, Institut Teknologi Bandung, Bali, Indonesia, pp. 117-122.
Sri Ravindrarajah, R & Jones, W 1970, 'Properties of Adjusted Density High-Performance Concrete', Advances in Structures, International Conference on Advances in Structures, A.A. Balkema, Swets & Zeitlinger B.V. Lissie, The Netherlands, Sydney, Australia, pp. 1011-1016.
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.
