Digital Commons Network^™

Effect Of Microstructure On The Stability Of Retained Austenite In Transformation-Induced-Plasiticity Steels, I B. Timokhina, P D. Hodgson, E V. Pereloma

Faculty of Engineering and Information Sciences - Papers: Part A

Two Fe-0.2C-1.55Mn-1.5Si (in wt pct) steels, with and without the addition of 0.039Nb (in wt pct), were studied using laboratory rolling-mill simulations of controlled thermomechanical processing. The microstructures of all samples were characterized by optical metallography, X-ray diffraction (XRD), and transmission electron microscopy (TEM). The microstructural behavior of phases under applied strain was studied using a heat-tinting technique. Despite the similarity in the microstructures of the two steels (equal amounts of polygonal ferrite, carbide-free bainite, and retained austenite), the mechanical properties were different. The mechanical properties of these transformation-induced-plasticity (TRIP) steels depended not only on the individual behavior of all …

Massive Increase In The Stiffness Of The Human Lens Nucleus With Age: The Basis For Presbyopia?, Karl Robert Heys, Sandra Leigh Cram, Roger J W Truscott

Faculty of Engineering and Information Sciences - Papers: Part A

Purpose: To determine the stiffness of different regions of human lenses as a function of age, and to correlate the biophysical measurements in the lens center with nuclear water content.

Methods: A custom made probe fitted to a dynamic mechanical analyzer was employed to measure stiffness values at 1 mm increments across equatorial sections of individual human lenses. Thermogravimetric analysis was used to determine the percentage water content in the nuclei of human lenses.

Results: There was a pronounced increase in lens stiffness over the age range from 14 to 78. In the nucleus, stiffness values varied almost 1,000 fold …

Mansfield's Imprimitivity Theorem For Arbitrary Closed Subgroups, Astrid An Huef, Iain Raeburn

Faculty of Engineering and Information Sciences - Papers: Part A

No abstract provided.

Cuntz-Krieger Algebras Of Infinite Graphs And Matrices, Iain Raeburn, Wojciech Szymanski

Faculty of Engineering and Information Sciences - Papers: Part A

We show that the Cuntz-Krieger algebras of infinite graphs and infinite {0,1}-matrices can be approximated by those of finite graphs. We then use these approximations to deduce the main uniqueness theorems for Cuntz-Krieger algebras and to compute their K-theory. Since the finite approximating graphs have sinks, we have to calculate the K-theory of Cuntz-Krieger algebras of graphs with sinks, and the direct methods we use to do this should be of independent interest.

Energy Injection By Distributed Generation For Improvement In Feeder-Voltage Profile, Kashem M. Muttaqi, Gerard Ledwich

Faculty of Engineering and Information Sciences - Papers: Part A

No abstract provided.

What Prevent B2b Ecommerce Adoption In Developing Countries?: A Socio-Cultural Perspective, Savanid Vatanasakdakul, William Tibben, Joan Cooper

Faculty of Engineering and Information Sciences - Papers: Part A

It is widely believed that B2B e-commerce will help firms in developing countries to reduce cost and to improve their access to global market. Yet, developing countries are still some way from success in their adoption of B2B e-commerce. This paper explores social and cultural perspectives that impact on B2B e-commerce adoption in developing countries. Interviews were conducted with key informants from various industries in Thailand. Some common problems related to social and cultural issues faced by industries are presented. It was found that even though B2B e-commerce was implemented in many firms, its use was still very limited. Firms …

Myth Or Fact: Is Open Source Software More Secure Than Closed Source Software?, Daniel Saffioti, Gene Awyzio, Robert B. K. Brown

Faculty of Engineering and Information Sciences - Papers: Part A

This paper examines one aspect of quality that organizations look for when selecting software, namely security. Studies over time have indicated that security; scalability, interoperability and flexibility are important however the major issue has always been support. This has led to the sometimes inflexible concept of Standard Operating Environments (SOEs) within organisations. Whilst SOEs provide many benefits to an organisation they can leave them vulnerable to several large security risks. CERT statistics show that security incidents have increased six fold since 2000 [1]. This paper will examine trends in both open and closed software development for a number of platforms …

Summability For Nonunital Spectral Triples, Adam C. Rennie

Faculty of Engineering and Information Sciences - Papers: Part A

This paper examines the issue of summability for spectral triples for the class of nonunital algebras. For the case of (p, -) summability, we prove that the Dixmier trace can be used to define a (semifinite) trace on the algebra of the spectral triple. We show this trace is well-behaved, and provide a criteria for measurability of an operator in terms of zeta functions. We also show that all our hypotheses are satisfied by spectral triples arising from eodesically complete Riemannian manifolds. In addition, we indicate how the Local Index Theorem of Connes-Moscovici extends to our nonunital setting.

An Investigation Into The Effects Of Heat Transfer On The Motion Of A Spherical Bubble, P J Harris, H Al-Awadi, Wee King Soh

Faculty of Engineering and Information Sciences - Papers: Part A

This paper investigates the effect of heat transfer on the motion of a spherical bubble in the vicinity of a rigid boundary. The effects of heat transfer between the bubble and the surrounding fluid, and the resulting loss of energy from the bubble, can be incorporated into the simple spherical bubble model with the addition of a single extra ordinary differential equation. The numerical results show that for a bubble close to an infiniterigid boundary there are significant differences in both the radius and Kelvin impulse of the bubble when the heat transfer effects are included.

The Limiting Ideal Theory For Shear-Index Cohesionless Granular Materials, Grant Cox, James Hill

Faculty of Engineering and Information Sciences - Papers: Part A

To model cohesionless granular flow using continuum theory, the usual approach is to assume the cohesionless Coulomb-Mohr yield condition. However, this yield condition assumes that the angle of internal friction is constant, when according to experimental evidence for most powders the angle of internal friction is not constant along the yield locus, but decreases for decreasing normal stress component σ from a maximum value of π/2. For this reason, we consider here the more general yield function which applies for shear-index granular materials, where the angle of internal friction varies with σ. In this case, failure due to frictional slip …

Development And Analysis Of A Novel Vertical Axis Wind Turbine, Paul Cooper, Oliver C. Kennedy

Faculty of Engineering - Papers (Archive)

This paper describes the development of a novel vertical axis wind turbine used for teaching and research purposes. The device is designed to operate at low tip speed ratios and features blades that are symmetric about the mid-chord plane. The blades are actively pitched by means of a mechanical system so that the chord of each blade rotates by 180º for every revolution of the main rotor. One of the attractions of the device is that it is self-starting and produces relatively high torque. A multiple streamtube analysis of the device has been developed and numerical predictions for the performance …

Comparison Of Rotary Valve And Blowtank Feed Rate Capacities, David B. Hastie, Peter W. Wypych, Ian Frew, Christopher David Cook

Faculty of Engineering - Papers (Archive)

Rotary valves and blowtanks are widely used in industry for the pneumatic conveying of products, each having their pros and cons depending on the required application. This paper aims to show the differing results that can be obtained when conveying a product through a common pipeline using either a drop-through rotary valve or a bottom discharge blowtank. The rotary valve system has a number of issues, the main one being air leakage effects, whereas the blowtank system does not as it is an enclosed unit. The results of these experiments showed dramatic differences in product tonnage.

Drying Of Water Treatment Plant Residuals, Ali Mohammad Gharaibeh, Muttucumaru Sivakumar, Hagare Dharmappa

Faculty of Engineering - Papers (Archive)

Drying of ferric chloride water treatment plant residuals have been studied in two experimental sand drying beds. One bed was open and the other was covered with glass to study respectively the open bed drying of residuals under normal weather conditions and passive solar energy drying. The covered bed was fabricated, with a view, to simulate the solar distillation stills. A weather station was used to monitor the dynamic weather conditions in order to study their effect on the drying process. Solids content, drainage water volumes and distillate from the covered bed were measured on a daily basis. The aim …

World Water Crisis Looms, Luke Scott, Muttucumaru Sivakumar, Dharmappa Hagare

Faculty of Engineering - Papers (Archive)

An investigation was undertaken to develop a robust solar water purification system for remote areas that have neither suitable potable water nor energy supplies. A study of the challenges of global water supply and existing treatment methods was made to aid the development of the design. Current world water resources are examined regarding climate change, population growth and irrigation and the likely effects are assessed for human health and mortality, potential for conflict, economics and effect on ecosystems. Solutions are posed in the form of development goals, wastewater reuse and desalination. Objectives for the design of effective desalination systems are …

Widmanstatten Ferrite Plate Formation In Low-Carbon Steels, Dominic Phelan, Rian Dippenaar

Faculty of Engineering and Information Sciences - Papers: Part A

The mechanism by which Widmanstätten ferrite plates nucleate and grow in low-carbon steels has been studied. In-situ laser scanning confocal microscopy (LSCM) observations, optical microscopy, and electron backscattered diffraction (EBSD) techniques have been used to characterize the relationship between grain boundary allotriomorphs and Widmanstätten ferrite plates. The issue of where Widmanstätten ferrite plates nucleate is one of some debate, with theories including morphological instability and sympathetic nucleation. Evidence has been found that supports the theory of a sympathetic nucleation mechanism being responsible for the formation of Widmanstätten ferrite plates. The EBSD measurements have shown that low-angle misorientations of between 5 …

Fricke Dosimetry For Synchrotron Stereotactic Radiotherapy, C Boudou, M C Biston, J F Adam, A Joubert, S Corde, A M Charvet, F Esteve, H Elleaume

Faculty of Engineering and Information Sciences - Papers: Part A

In synchrotron stereotactic radiotherapy (SSR) the tumor is loaded with a high Z element, and exposed to monochromatic x-rays from a synchrotron source, in stereotactic conditions. The SSR treatment efficiency is related to the heavy element concentration achievable in the tumor, to the radiation energy, and the irradiation geometry [1,2]. The experimental dose verification of SSR in three dimensions with a good spatial resolution is highly desirable for radiotherapy [3]. In this study, Fricke dosimeter and Monte Carlo calculations were employed for assessing 2D dose distribution.

Analysis Of Inelastic Interactions For Therapeutic Proton Beams Using Monte Carlo Simulation, Anatoly B. Rosenfeld, A. J. Wroe, I. Cornelius, M. Reinhard, D. Alexiev

Faculty of Engineering - Papers (Archive)

The irradiation of various tissue-like materials by therapeutic proton beams was simulated using Monte Carlo. The contribution of inelastic reaction products to the depth-dose distribution was determined. The use of silicon microdosimeters for verifying Monte Carlo calculations was also investigated. The importance of these studies to Monte Carlo-based treatment planning systems is emphasized.

Tungsten Disulfide Nanotubes For Lithium Storage, G. X. Wang, S. Bewlay, J. Yao, Hua-Kun Liu, S. X. Dou

Faculty of Engineering - Papers (Archive)

WS2 nanotubes were synthesized by sintering amorphous WS3 at high temperature under flowing hydrogen. High-resolution transmission electron microscopy observation revealed that the as-prepared WS2 nanotubes have an open end with an inner hollow core of about 4.6 nm. We studied the lithium intercalation behavior of WS2 nanotubes. The WS2 nanotubes demonstrated a stable cyclability in a wide voltage range ~0.1-3.1 V vs. Li/Li1). The nanotubes could provide a new class of electrode materials for lithium-ion batteries.

Modeling Of Contaminant Transport In On-Site Waste Disposal Systems, Thidarat Bunsri, Dharmappa Hagare, Muttucumaru Sivakumar

Faculty of Engineering - Papers (Archive)

One of the most common problems of septic systems is poor drainage in the field. Septic systems release number of organic contaminants that cause groundwater pollution, especially organic substances, nutrients and pathogenic microorganisms. However, there are mechanisms that operate between soil and contaminants, which can purify the septic tank effluent. Below the drainage field, soil is separated into two zones; unsaturated and saturated zone, which provide the water movement mainly in vertical and horizontal direction, respectively. The purpose of this paper is to develop a conceptual model and to define governing equations for the transport of septic tank effluent in …

Techniques For Predicting Total Phosphorus In Urban Stormwater Runoff At Unmonitored Catchments, Daniel May, Muttucumaru Sivakumar

Faculty of Engineering - Papers (Archive)

This paper investigates the applicability of using artificial neural network (ANN) and multilinear regression models to predict urban stormwater quality at unmonitored catchments. Models were constructed using logarithmically transformed environmental data. Violation of the assumption of data independence lead to the inclusion of insignificant variables when a straightforward stepwise regression was applied. To overcome this problem, cross validation was used to determine when to stop adding variables. Regression models calibrated using event mean concentration (EMC) as the dependent variable were more accurate than those using event load. Regression models developed on a regional subset of data were more accurate than …

Uranium Doping And Thermal Neutron Irradiation Flux Pinning Effects In Mgb2, Tania M. Silver, J. Horvat, M. Reinhard, P. Yao, S. Keshavarzi, P. Munroe, S. X. Dou

Faculty of Engineering - Papers (Archive)

The U/n method is a well-established means of improving flux pinning and critical current performance in cuprate superconductors. The method involves the doping of the superconductor with 235U followed by irradiation with thermal neutrons to promote fission. The resultant columnar damage tracks produced by the energetic fission products pin flux vortices and improve critical current performance in magnetic fields. No such improvement could be observed when the U/n method was applied to the MgB2 superconductor. No fission tracks could be observed in TEM, even for samples that were irradiated at the highest fluence. Gamma-ray spectroscopy indicated that fission had occurred …

The Electron Energy Spectrum And Thermionic Device Efficiency, Mark F. O'Dwyer, T. E. Humphrey, R. A. Lewis, C. Zhang

Faculty of Engineering - Papers (Archive)

The influence of the electron energy spectrum of solid-state thermionic devices on electronic efficiency is analyzed. Calculations are performed on both single and multibarrier GaAs/AlGaAs and InGaAs/InAlAs systems. Analysis reveals a wide barrier is desirable for single-barrier thermionic devices due to the associated sharpness in the electron energy spectrum. It is also shown that high electronic efficiency may be achieved in multibarrier thermionic devices consisting of thin barriers, which would separately give low efficiency, but together can be arranged to produce a desirable electron energy spectrum.

Modelling Trust Relationships In Distributed Environments, Weiliang Zhao, Vijay Varadharajan, George Bryan

Faculty of Engineering - Papers (Archive)

Trust management and trustworthy computing are becoming increasingly significant at present. Over the recent years there have been several research works that have addressed the issue of trust management in distributed systems. However a clear and comprehensive definition that can be used to capture a range of commonly understood notions of trust is still lacking. In this paper, we give a formal definition of trust relationship with a strict mathematical structure that can not only reflect many of the commonly used extreme notions of trust but also provides a taxonomy framework where a range of useful trust relationships can be …

A Note On Devaney's Definition Of Chaos, Joseph Tonien

Faculty of Engineering and Information Sciences - Papers: Part A

Devaney defines a function to be chaotic if it satisfies three conditions: transitivity, having dense set of periodic points and sensitive dependence on initial conditions. Banks et al prove that if the function is continuous then the third conditioin is implied from the first two and therefore is redundant. However, if the function is not assumed to be continuous, then it is not known if the third condition is redundant or not.

In this note, without assuming the function is continuous, we prove that the third condition is redundant if the underlying topological space is not precompact.

Linear Code Implies Publicf-Key Traitor Tracing With Revocation, Joseph Tonien, Rei Safavi-Naini

Faculty of Engineering and Information Sciences - Papers: Part A

In this paper, we show that the linear-coded Kurosawa–Desmedt scheme can be modified to allow revocation of users, that is to show a revocation scheme can be derived from a linear code.

Using Self-Regulated Learning To Manage The Discomfort Of Becoming Fluent With Information Technology, Victoria M. Neville, Sue Bennett

Faculty of Engineering and Information Sciences - Papers: Part A

The technologically complex and changing world of the twenty first century requires teachers who are both knowledgeable and skilled in using information technology in their pedagogical practices. The changing nature of information technology means that teachers need to be flexible in how they use information technology in their teaching, adaptable to the changes in technological developments, problem solvers in unfamiliar circumstances, and continuing learners throughout their professional life. These ideas are encapsulated in the concept of fluency with information technology, or FITness (Committee on Information Technology Literacy, 1999). This research study, in progress, uses an interpretive, qualitative methodological approach to …

Geometric Modelling Of The Temporal Bone For Cochlea Implant Simulation, Catherine Todd, Fazel Naghdy, S. J. O'Leary

Faculty of Engineering - Papers (Archive)

The first stage in the development of a clinically valid surgical simulator for training otologic surgeons in performing cochlea implantation is presented. For this purpose, a geometric model of the temporal bone has been derived from a cadaver specimen using the biomedical image processing software package Analyze (AnalyzeDirect, Inc) and its three-dimensional reconstruction is examined. Simulator construction begins with registration and processing of a Computer Tomography (CT) medical image sequence. Important anatomical structures of the middle and inner ear are identified and segmented from each scan in a semi-automated threshold-based approach. Linear interpolation between image slices produces a three-dimensional volume …

Single Detector-Dual Scintillator Anti-Comptom Probes, Anatoly B. Rosenfeld, Michael L. Lerch, George J. Takacs, A Getkin, V Perevertailo

Faculty of Engineering - Papers (Archive)

Anti¬-Compton spectrometers have many applications in the fields of safeguards, medicine and security. One of the most important applications is in the location of low energy gamma sources in the presence of high-¬energy gamma background or the location of high-¬energy gamma radiation sources hidden within the same spread of radiation background. In most situations space constraints limit the application of large size detectors or classical anti¬-Compton spectrometers. We have designed a compact anti-¬Compton spectrometer based on a single chip, dual silicon photodetector optically coupled to isolated, annular scintillators. Preliminary room temperature testing with Csl(TI) and LYSO scintillators demon¬strate the readout …

Analysis And Design Of Double-Sided High-Rise Steel Pallet Rack Frames, Lip H. Teh, Gregory J. Hancock, Murray J. Clarke

Faculty of Engineering - Papers (Archive)

In routine design of steel storage rack frames, it is far more common to perform two dimensional (2D) rather than three dimensional (3D) linear buckling analyses. In this paper, it is demonstrated that the global buckling behavior of high-rise steel storage rack frames may not be revealed by 2D buckling analyses as 3D interaction modes are involved. It is shown that the monosymmetric upright columns of a high-rise rack frame fail in a flexural–torsional mode due to the shear-center eccentricity of the sections, and that the 3D frame buckling analysis is more reliable in determining the critical members of a …

The Effect Of An Applied Electrical Potential On Refractory Corrosion By Slag, Brian J. Monaghan, Sharon Nightingale, Q Dong

Faculty of Engineering - Papers (Archive)

An investigation has been carried out to assess the effects of an applied voltage on the dissolution rate of MgO refractory in a steelmaking like slag. In this study corrosion results obtained from dip tests using a dense direct bonded MgO refractory in a CaO-SiO2-Fe2O3-FeO-MgO slag are presented. These results demonstrate that the application of a voltage across a dense MgO refractory-slag interface can change the rate of refractory dissolution. For the slag composition used and the voltage range tested, it was found that a maximum corrosion rate was obtained at a voltage setting of –0.45V. The results of this …