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Full-Text Articles in Engineering
Parametric Study Of Unsaturated Drainage Layers In A Capillary Barrier, C. E. Morris, J. C. Stormont
Parametric Study Of Unsaturated Drainage Layers In A Capillary Barrier, C. E. Morris, J. C. Stormont
Faculty of Engineering - Papers (Archive)
Unsaturated drainage layers (UDLs) have been demonstrated to greatly increase the lateral diversion capacity of capillary barriers. The inclusion of a UDL allows native soils suitable for vegetation growth to be used as the finer soil as lateral drainage properties of the layer no longer need to be considered. A comprehensive numerical study was conducted to investigate the influence of the interface slope and the UDL material on the system’s ability to laterally divert downward moving moisture. A capillary barrier system with and without a UDL was simulated for 10 years using daily varying climatic data for three locations in …
Dielectric Function Of An Electron Gas Under Intense Laser Radiation In Quantizing Magnetic Fields, W. Xu
Dielectric Function Of An Electron Gas Under Intense Laser Radiation In Quantizing Magnetic Fields, W. Xu
Faculty of Engineering - Papers (Archive)
A detailed theoretical study on dielectric function of a three-dimensional electron gas (3DEG), subject to linearly polarized intense laser field and to strong static magnetic field, is presented. Using the Green’sfunction approach, I have derived the density-density correlation function and the random-phaseapproximation dielectric function for a 3DEG in t and representation. It is found that in the presence of intense terahertz laser field, the dielectric function of an electron gas depends strongly on frequency and intensity of the electromagnetic radiation. A number of important radiation effects, pertinent to the application of the free-electron laser sources developed recently, are presented and …
Nature And Properties Of Acid Sulphate Soils In Drained Coastal Lowlands In New South Wales, Buddhima Indraratna, B. Blunden, A. Nethery
Nature And Properties Of Acid Sulphate Soils In Drained Coastal Lowlands In New South Wales, Buddhima Indraratna, B. Blunden, A. Nethery
Faculty of Engineering - Papers (Archive)
Acid sulphate soils pose severe constraints to the protection of engineering infrastructure, sustainable agriculture and environmental quality in coastal estuarine systems in many parts of Australia. The nature and properties of acid sulphate soils are described with reference to data collected from intensively drained coastal lowlands located on the South Coast of New South Wales.
Nickel Hydroxide As An Active Material For The Positive Electrode In Rechargeable Alkaline Batteries, J Chen, D. H. Bradhurst, S X. Dou, Hua-Kun Liu
Nickel Hydroxide As An Active Material For The Positive Electrode In Rechargeable Alkaline Batteries, J Chen, D. H. Bradhurst, S X. Dou, Hua-Kun Liu
Faculty of Engineering - Papers (Archive)
Spherical nickel hydroxide powders coprecipitated with the additives Ca(OH)2, Co(OH)2, and Zn(OH)2 were prepared through a spraying technique. These powders, which have a higher tapping density and a much smaller pore volume and crystalline size than conventional powders, were used as the active materials of nickel hydroxide electrodes. The effects of the Ca(OH)2, Co(OH)2, and Zn(OH)2 additions on electrode properties such as charge-discharge, reversibility of the electrode reaction, and cycle life, were studied. The relationship between the electrode swelling and the formation of g-NiOOH was also investigated. The results show that nickel hydroxide powders having a smaller crystallite size show …
Carbon Nanotube Actuators, R. H. Baughman, C. X. Cui, A. A. Zakhidov, Z. Iqbal, J. N. Barisci, Geoffrey M. Spinks, G G. Wallace, A. Mazzoldi, D. De Rossi, A. G. Rinzler, O. Jaschinski, S. Roth, M. Kertesz
Carbon Nanotube Actuators, R. H. Baughman, C. X. Cui, A. A. Zakhidov, Z. Iqbal, J. N. Barisci, Geoffrey M. Spinks, G G. Wallace, A. Mazzoldi, D. De Rossi, A. G. Rinzler, O. Jaschinski, S. Roth, M. Kertesz
Faculty of Engineering - Papers (Archive)
Electromechanical actuators based on sheets of single-walled carbon nanotubes were shown to generate higher stresses than natural muscle and higher strains than high-modulus ferroelectrics. Like natural muscles, the macroscopic actuators are assemblies of billions of individual nanoscale actuators. The actuation mechanism (quantum chemical-based expansion due to electrochemical double-layer charging) does not require ion intercalation, which limits the life and rate of faradaic conducting polymer actuators. Unlike conventional ferroelectric actuators, low operating voltages of a few volts generate large actuator strains. Predictions based on measurements suggest that actuators using optimized nanotube sheets may eventually provide substantially higher work densities per cycle …
Critical Current Degradation Caused By Winding Process Of Bi-2223/Ag Hts Wire In The Form Of A Coil, Jian X. Jin, S X. Dou, Hua-Kun Liu, T Hardono, Christopher D. Cook, C. Grantham
Critical Current Degradation Caused By Winding Process Of Bi-2223/Ag Hts Wire In The Form Of A Coil, Jian X. Jin, S X. Dou, Hua-Kun Liu, T Hardono, Christopher D. Cook, C. Grantham
Faculty of Engineering - Papers (Archive)
High T, superconducting (HTS) (Bi,Pb)2Sr2Ca2 Cu3010+xA g-clad wire has potential for practical applications in the form of a coil or a winding. This HTS wire has strong magnetic field-dependent and mechanical strain-dependent critical currents, consequently it faces a severe problem of critical current degradation when it is used in the form of a coil. To design a winding with this conductor, the critical current degradation has to be identified with relation to the magnetic fields and the winding process. This is important to optimize an appropriate coil winding procedure using this HTS wire. A specially designed non-inductive sample has been …
Measurements Of Ac Losses In Htsc Wires Exposed To An Alternating Field Using Calorimetric Methods, Tri Hardono, Christopher D. Cook, Jian Xun Jin
Measurements Of Ac Losses In Htsc Wires Exposed To An Alternating Field Using Calorimetric Methods, Tri Hardono, Christopher D. Cook, Jian Xun Jin
Faculty of Engineering - Papers (Archive)
Calorimetric methods for AC loss measurement for short superconducting wires have been investigated. The design, operation and results obtained from an experimental calorimeter are described. With these methods the total loss of a short superconducting sample exposed to a 50 Hz alternating field, both perpendicular and axial, have been measured with an accuracy of microwatts per centimeter. The sample is a 6 centimeter long (Bi,Pb)SrCaCuO-2223 silver-sheathed multifilamentary wire prepared by powder-in-tube techniques. The hysteresis part of the loss may be obtained by taking the eddy current component of the silver sheath from the total loss and by neglecting the coupling …
Simulated Annealing: Searching For An Optimal Temperature Schedule, Harry Cohn, Mark James Fielding
Simulated Annealing: Searching For An Optimal Temperature Schedule, Harry Cohn, Mark James Fielding
Faculty of Engineering and Information Sciences - Papers: Part A
A sizable part of the theoretical literature on simulated annealing deals with a property called convergence, which asserts that the simulated annealing chain is in the set of global minimum states of the objective function with probability tending to 1. However, in practice, the convergent algorithms are considered too slow, whereas a number of nonconvergent ones are usually preferred. We attempt a detailed analysis of various temperature schedules. Examples will be given of when it is both practically and theoretically justified to use boiling, fixed temperature, or even fast cooling schedules which have a small probability of reaching global minima. …
Magnetic Circuit Of A Synchronous Reluctance Motor, P P. Ciufo, D. Platt, B S. P Perera
Magnetic Circuit Of A Synchronous Reluctance Motor, P P. Ciufo, D. Platt, B S. P Perera
Faculty of Engineering and Information Sciences - Papers: Part A
This paper presents a model of the magnetic circuit for an axially laminated synchronous reluctance motor. The basis of the modelling technique is the determination of a value for an equivalent ``q-channel'' reluctance. This reluctance contains all the effects of paths available to q-axis flux through the rotor body. Expressions for the distribution of airgap and other motor fluxes have been developed from basic analyses involving mmf and continuity of flux. The foundations of all of these expressions are the physical parameters of the motor. The equations developed have been applied to a 370 W motor and the results from …
Quantitative Landslide Hazard Assessment In An Urban Area, Phillip N. Flentje, Robin N. Chowdhury
Quantitative Landslide Hazard Assessment In An Urban Area, Phillip N. Flentje, Robin N. Chowdhury
Faculty of Engineering and Information Sciences - Papers: Part A
Before decisions can be made concerning the management of sloping areas subject to landsliding, systematic approaches for hazard and risk assessment must be developed. This paper is limited to a discussion of hazard assessment and describes quantitative approaches which have been developed for existing landslides. Consideration of areas of potential landsliding is outside the scope of the paper. The approach described here is based on (a) monitoring of subsurface shear movement at instrumented sites and (b) the percentage exceedance time of cumulative rainfalls considering different selected periods of antecedent rainfall. This approach is used in conjunction with a simpler approach, …
Experimental Investigation Into Segregation Of Bulk Solids During Gravity Filling Of Storage Bins, David B. Hastie, Peter W. Wypych
Experimental Investigation Into Segregation Of Bulk Solids During Gravity Filling Of Storage Bins, David B. Hastie, Peter W. Wypych
Faculty of Engineering - Papers (Archive)
This paper explains the phenomenon of segregation and previous methods used in its quantification. Also explained is the current research, which has attempted to develop a two dimensional sampling technique to quantify the degree of mixing present under gravity fill conditions. Binary mixtures have been prepared in varying proportions and charged into a test rig where sampling has taken place and the results analysed. From these results, a relationship between degree of mixing and product proportion has been developed.
Landslide Risk Assessment - Development Of A Hazard Consequence Approach, Chit Ko Ko, Phillip N. Flentje, Robin N. Chowdhury
Landslide Risk Assessment - Development Of A Hazard Consequence Approach, Chit Ko Ko, Phillip N. Flentje, Robin N. Chowdhury
Faculty of Engineering and Information Sciences - Papers: Part A
Several Landslide Hazard and Risk Assessment methods have been developed and used in the State of New South Wales (NSW), Australia. The Rail Services Australia Geotechnical Services and the Roads and Traffic Authority of NSW have each developed Risk Assessment procedures suitable to their own specific needs. A generic risk management methodology is presented in the Australian Standard/New Zealand Standard (AS/NZS) 4360:1995. An approach similar to the (AS/NZS) 4360:1995 Risk Management Standard has been applied by a NSW State Emergency Services geotechnical team (which included one of the writers) to 191 problem sites in the Wollongong Area, following a major …
Network Reconfiguration For Load Balancing In Distribution Networks, Kashem M. Muttaqi, Velappa Ganapathy, G G. Jasmon
Network Reconfiguration For Load Balancing In Distribution Networks, Kashem M. Muttaqi, Velappa Ganapathy, G G. Jasmon
Faculty of Engineering and Information Sciences - Papers: Part A
Network reconfiguration of a power distribution system is an operation to alter the topological structure of distribution feeders by changing opedclosed status of sectionalising and tie switches. By transferring loads from the heavily loaded feeders to the lightly loaded ones, network reconfiguration can balance feeder loads and alleviate overload conditions of a network. The branch load-balancing index and the overall system load-balancing index are used to determine the loading conditions of the system and maximum system loading capacity. The index value has to be minimum in the optimal configuration of load balancing. For optimal load balancing condition the branch load-balancing …
The Electrode Properties Of Mg1.9al0.1ni0.8co0.1mn0.1 Alloy By Mechanical Grinding With Ni Powders, L. Sun, Hua-Kun Liu, D. H. Bradhurst, S. X. Dou
The Electrode Properties Of Mg1.9al0.1ni0.8co0.1mn0.1 Alloy By Mechanical Grinding With Ni Powders, L. Sun, Hua-Kun Liu, D. H. Bradhurst, S. X. Dou
Faculty of Engineering - Papers (Archive)
A modified magnesium alloy of composition Mg1.9Al0.1Ni0.8Co0.1Mn0.1 was prepared by mechanical grinding with Ni powder for periods up to 120 h. The resulting structures of the Mg1.9Al0.1Ni0.8Co0.1Mn0.1 alloys were found to be amorphous. The electrodes of the modified Mg1.9Al0.1Ni0.8Co0.1Mn0.1 alloys had large discharge capacities. At a discharge current rate of 50 mA/g, the capacity was 630 mAh/g after 50 h of mechanical grinding and 510 mAh/g after 120 h of mechanical grinding.
Fission Converter And Metal–Oxide–Semiconductor Field Effect Transistor Study Of Thermal Neutron Flux Distribution In An Epithermal Neutron Therapy Beam, G. I. Kaplan, Anatoly B. Rosenfeld, B. J. Allen, J. A. Coderre, H. B. Liu
Fission Converter And Metal–Oxide–Semiconductor Field Effect Transistor Study Of Thermal Neutron Flux Distribution In An Epithermal Neutron Therapy Beam, G. I. Kaplan, Anatoly B. Rosenfeld, B. J. Allen, J. A. Coderre, H. B. Liu
Faculty of Engineering - Papers (Archive)
The depth distribution of the thermal neutron flux is a major factor in boron neutron capture therapy (BNCT) in determining the efficiency of cell sterilization. In this paper the fission detector method is developed and applied to measure the in-phantom thermal neutron flux depth distribution. Advantages of the fission detector include small size, direct measurement of thermal neutron flux in a mixed radiation field of BNCT beam, self-calibration, and the possibility of on-line measurement. The measurements were performed at epithermal a BNCT facility. The experimental results were compared with the thermal neutron flux calculated by the Monte Carlo method and …
Positive In-Plane And Negative Out-Of-Plane Magnetoresistance In The Overdoped High-Temperature Superconductor Bi2sr2cacu2o8 + X, G. Heine, W. Lang, Xiaolin Wang, S. X. Dou
Positive In-Plane And Negative Out-Of-Plane Magnetoresistance In The Overdoped High-Temperature Superconductor Bi2sr2cacu2o8 + X, G. Heine, W. Lang, Xiaolin Wang, S. X. Dou
Faculty of Engineering - Papers (Archive)
The in-plane and out-of-plane magnetoresistances of moderately overdoped Bi2Sr2CaCu2O8+x single crystals have been studied from Tc+5 K to Tc+100 K with the magnetic field oriented perpendicular and parallel to the current, respectively. The in-plane magnetoresistance is positive, the out-of-plane magnetoresistance negative, and their temperature variations depend on the orientation of the magnetic field. A recent theory for superconducting order parameter fluctuations is extended for the interaction of carrier spins with the magnetic field. The anomalous, anisotropic magnetoresistance can be described well by a unique set of physical parameters, which …
Central-Cell Corrections For Si And S In Gaas In A Strong Magnetic Field, R. J. Heron, R. A. Lewis, Philip E. Simmonds, R. P. Starrett, A. V. Skougarevsky, R G. Clark, C. R. Stanley
Central-Cell Corrections For Si And S In Gaas In A Strong Magnetic Field, R. J. Heron, R. A. Lewis, Philip E. Simmonds, R. P. Starrett, A. V. Skougarevsky, R G. Clark, C. R. Stanley
Faculty of Engineering - Papers (Archive)
The central-cell correction has been determined experimentally for the two donor impurities S and Si in GaAs. Data have been obtained for magnetic fields to 39 T, corresponding to γ~6. The observed behavior is in good agreement with theory. The analysis permits accurate evaluation of zero-field central-cell corrections, yielding 0.110 and 0.059 meV for S and Si, respectively.
Quantum Point Contact In A Magnetic Field: Far-Infrared Resonant Heating Observed In Photoconductivity, R. J. Heron, R. A. Lewis, B. E. Kane, G. R. Facer, R. G. Clark, A. S. Dzurak, N. E. Lumpkin, R. P. Starrett, D. G. Rickel, L. N. Pfeiffer, K. W. West
Quantum Point Contact In A Magnetic Field: Far-Infrared Resonant Heating Observed In Photoconductivity, R. J. Heron, R. A. Lewis, B. E. Kane, G. R. Facer, R. G. Clark, A. S. Dzurak, N. E. Lumpkin, R. P. Starrett, D. G. Rickel, L. N. Pfeiffer, K. W. West
Faculty of Engineering - Papers (Archive)
We report on the far-infrared photoresponse of a quantum point contact device fabricated on a top-gated GaAs/AlGaAs heterostructure. The top-gated architecture avoids the disorder built into conventional modulation-doped structures. We observe a distinctive far-infrared magneto-photoresponse. This depends on the wavelength of the radiation and on the carrier density, which is controlled by the gate voltage. We conclude by comparison with transport data that the oscillations observed in photoconductivity and which are centred around the cyclotron energy arise from the resonant heating of electrons by the far-infrared radiation.
Instrumentation For Slope Stability - Experience From An Urban Area, P N. Flentje, R N. Chowdhury
Instrumentation For Slope Stability - Experience From An Urban Area, P N. Flentje, R N. Chowdhury
Faculty of Engineering and Information Sciences - Papers: Part A
This paper describes the monitoring of several existing landslides in an urban area near Wollongong in the state of New South Wales, Australia. A brief overview of topography and geology is given and reference is made to the types of slope movement, processes and causal factors. Often the slope movements are extremely slow and imperceptible to the eye, and catastrophic failures are quite infrequent. However, cumulative movements at these slower rates do, over time, cause considerable distress to structures and disrupt residential areas and transport routes. Inclinometers and piezometers have been installed at a number of locations and monitoring of …
Consideration Of Probability Assessments Relevant To Hazard And Risk For Landslides, R N. Chowdhury, P N. Flentje
Consideration Of Probability Assessments Relevant To Hazard And Risk For Landslides, R N. Chowdhury, P N. Flentje
Faculty of Engineering and Information Sciences - Papers: Part A
Probability of occurrence is the most important component of landslide hazard and risk and this paper outlines different approaches for its assessment. The reasons for the popularity of qualitative approaches are first outlined. Quantitative approaches can be best applied if the important influencing factors and issues are fully understood. Formal probabilistic approaches are often based on geotechnical models or on a combination of hydrological and geotechnical models. The paper also highlights the situations for which the performance function must be formulated in terms of lateral displacements rather than the conventional safety factor. Reference is then made to a procedure, based …
Aspects Of Recent Landslide Research At The University Of Wollongong, Robin N. Chowdhury, Phillip N. Flentje, Chit Ko Ko
Aspects Of Recent Landslide Research At The University Of Wollongong, Robin N. Chowdhury, Phillip N. Flentje, Chit Ko Ko
Faculty of Engineering and Information Sciences - Papers: Part A
This paper introduces the issues which are of critical importance to landslide hazard and risk assessment and management. These include understanding of probability and consequence, the separation of the role of site-dependent factors from that of influencing/triggering natural events and the factors influencing target levels of risk. The research completed at the University of Wollongong is then outlined. This includes the development of an observational approach based on monitoring of subsurface movements at individual sites and appropriate use of rainfall data in terms of the concept of annual rainfall percentage exceedance time (ARPET). Attention is then focused on current research …
Geotechnical Assessment And Management Of 148 Landslides Triggered By A Major Storm Event In Wollongong, Australia, P N. Flentje, R N. Chowdhury
Geotechnical Assessment And Management Of 148 Landslides Triggered By A Major Storm Event In Wollongong, Australia, P N. Flentje, R N. Chowdhury
Faculty of Engineering and Information Sciences - Papers: Part A
On the 17th August 1998 a severe rainfall event occurred over a widespread area of the City of Wollongong. During this storm, 1 person drowned and an estimated $50 to $100 million damage was caused to the City of Wollongong. Road access to the City was cut by raised water levels and debris flows covering and or scouring road and rail routes for up to 36 hours following this event. A geotechnical team of 3, including the first author, was organised at very short notice during the response phase of the emergency operations on the early morning of the 20th …
The Toeplitz Algebra Of A Hilbert Bimodule, Neal J. Fowler, Iain Raeburn
The Toeplitz Algebra Of A Hilbert Bimodule, Neal J. Fowler, Iain Raeburn
Faculty of Engineering and Information Sciences - Papers: Part A
Suppose a C ∗ -algebra A acts by adjointable operators on a Hilbert A -module X. Pimsner constructed a C ∗ -algebra 𝒪 X which includes, for particular choices of X , crossed products of A by Z , the Cuntz algebras 𝒪 n , and the CuntzKrieger algebras 𝒪 B. Here we analyse the representations of the corresponding Toeplitz algebra. One consequence is a uniqueness theorem for the ToeplitzCuntz-Krieger algebras of directed graphs, which includes Cuntz’s uniqueness theorem for 𝒪 ∞.
Optimization Of Soliton Amplitude In Dispersion-Decreasing Nonlinear Optical Fibres, Ken I M Mckinnon, Noel Smyth, Annette L. Worthy
Optimization Of Soliton Amplitude In Dispersion-Decreasing Nonlinear Optical Fibres, Ken I M Mckinnon, Noel Smyth, Annette L. Worthy
Faculty of Engineering and Information Sciences - Papers: Part A
The compression of a cw into a periodic train of noninteracting solitons by a dispersion-decreasing fiber is investigated with a variational method. To model the evolution from the cw to the soliton train, an elliptic-function-based expression is used as the trial function in the averaged Lagrangian. Both a continuous dispersion variation and a step dispersion variation in the fiber are considered. By use of an optimization method based on the approximate variational equations, the optimal dispersion profile required for achieving maximum pulse compression in a fixed length of fiber is determined. The solutions of the approximate equations are compared with …
Lie Algebras Of Cohomological Codimension One, Grant F. Armstrong, Grant Cairns, Gunky Kim
Lie Algebras Of Cohomological Codimension One, Grant F. Armstrong, Grant Cairns, Gunky Kim
Faculty of Engineering and Information Sciences - Papers: Part A
We show that if g is a finite dimensional real Lie algebra, then g has cohomological dimension cd(g) = dim(g) - 1 if and only if g is a unimodular extension of the two-dimensional non-Abelian Lie algebra aff.
Pseudo-Shock In Supersonic Injection Feeder, Ajit R. Godbole, Peter W. Wypych, Wee King Soh, Brent Matthews
Pseudo-Shock In Supersonic Injection Feeder, Ajit R. Godbole, Peter W. Wypych, Wee King Soh, Brent Matthews
Faculty of Engineering and Information Sciences - Papers: Part B
The flow in a Supersonic Injection Feeder involves relatively thick boundary layers in a narrow channel. When the pressures at the extremities of such a duct are adjusted to produce a compression shock, the shock structure is radically different from a plane discontinuity. This difference arises solely due to shock wave-boundary layer interaction, and gives rise to the so-called "pseudo-shock". In this paper, results of CFD simulations of a pseudo-shock in clean gas (air) are compared with predictions of the "Diffusion" model, the "Modified-Fanno" model and with experimental results. An analysis of the effect of small particles on pseudo-shock structure …
A Simulation Study Of The Kinetics Of Passage Of Co2 And N2 Through The Liquid/Vapor Interface Of Water, T Somasundaram, Marc In Het Panhuis, R M. Lynden-Bell, C H. Patterson
A Simulation Study Of The Kinetics Of Passage Of Co2 And N2 Through The Liquid/Vapor Interface Of Water, T Somasundaram, Marc In Het Panhuis, R M. Lynden-Bell, C H. Patterson
Australian Institute for Innovative Materials - Papers
The rate of passage of molecules of carbon dioxide and nitrogen through the vapor–liquid interface of water at 300 K is studied by simulation. Previous work has established the form of the free energy profile which has a minimum when the solute molecule is on the surface and a barrier between this state and solution in the bulk liquid. In one set of simulations, trajectories were initiated in the gas phase. From these, the average lifetime of molecules in the surface is determined to be considerably longer than the inverse of the energy relaxation rate, so that the sticking coefficient …