A comparison of finite difference and finite volume methods for solving the space fractional advection-dispersion equation with variable coefficients

Transport processes within heterogeneous media may exhibit non-classical diffusion or dispersion; that is, not adequately described by the classical theory of Brownian motion and Fick's law. We consider a space fractional advection-dispersion equation based on a fractional Fick's law. The equation involves the Riemann-Liouville fractional derivative which arises from assuming that particles may make large jumps. Finite difference methods for solving this equation have been proposed by Meerschaert and Tadjeran. In the variable coefficient case, the product rule is first applied, and then the Riemann-Liouville fractional derivatives are discretised using standard and shifted Grunwald formulas, depending on the fractional order. In this work, we consider a finite volume method that deals directly with the equation in conservative form. Fractionally-shifted Grunwald formulas are used to discretise the fractional derivatives at control volume faces. We compare the two methods for several case studies from the literature, highlighting the convenience of the finite volume approach.

Towards proximity-based passenger sensing on public transport buses

While substantial research on intelligent transportation systems has focused on the development of novel wireless communication technologies and protocols, relatively little work has sought to fully exploit proximity-based wireless technologies that passengers actually carry with them today. This paper presents the real-world deployment of a system that exploits public transit bus passengers’ Bluetooth-capable devices to capture and reconstruct micro- and macro-passenger behavior. We present supporting evidence that approximately 12% of passengers already carry Bluetooth-enabled devices and that the data collected on these passengers captures with almost 80 % accuracy the daily fluctuation of actual passengers flows. The paper makes three contributions in terms of understanding passenger behavior: We verify that the length of passenger trips is exponentially bounded, the frequency of passenger trips follows a power law distribution, and the microstructure of the network of passenger movements is polycentric.

Deformation with coupled chemical diffusion

The deformation of rocks is commonly intimately associated with metamorphic reactions. This paper is a step towards understanding the behaviour of fully coupled, deforming, chemically reacting systems by considering a simple example of the problem comprising a single layer system with elastic-power law viscous constitutive behaviour where the deformation is controlled by the diffusion of a single chemical component that is produced during a metamorphic reaction. Analysis of the problem using the principles of non-equilibrium thermodynamics allows the energy dissipated by the chemical reaction-diffusion processes to be coupled with the energy dissipated during deformation of the layers. This leads to strain-rate softening behaviour and the resultant development of localised deformation which in turn nucleates buckles in the layer. All such diffusion processes, in leading to Herring-Nabarro, Coble or “pressure solution” behaviour, are capable of producing mechanical weakening through the development of a “chemical viscosity”, with the potential for instability in the deformation. For geologically realistic strain rates these chemical feed-back instabilities occur at the centimetre to micron scales, and so produce structures at these scales, as opposed to thermal feed-back instabilities that become important at the 100–1000 m scales.

Engineering the surface of a sugarcane roller mill roll for grip and durability

Roller mills are typically used to crush sugarcane to express the juice from which sugar is manufactured. The mill rolls need to provide sufficient grip to ensure minimal sliding of the sugarcane along the roll surface. The rolls are subject to pressures up to 55 MPa from the sugarcane bagasse (as the sugarcane is called after first being crushed between a pair of rolls). The insoluble component of sugarcane includes typically 10% ash that largely originates from soil that is harvested with the cane. The sugarcane juice is acidic with pH typically between 5.0 and 5.5. As a result of ash and juice, the mill rolls are subjected to a range of abrasive and corrosive wear mechanisms. Solutions to provide grip and resist wear involve the selection of an appropriate roll shell material and compatible hard facing to provide the desired grip and wear characteristics. This paper reviews the various solutions that have been adopted for grip and durability for mill rolls and highlights the advantages and disadvantages of each method.

The diversity of interests in environmental governance : a challenge for the rule of law

The function of environmental governance and the principle of the rule of law are both controversial and challenging. To apply the principle of the rule of law to the function of environmental governance is perhaps even more controversial and challenging. A system of environmental governance seeks to bring together the range of competitive and potentially conflicting interests in how the environment and its resources are managed. Increasingly it is the need for economic, social and ecological sustainability that brings these interests – both public and private – together. Then there is the relevance of the principle of the rule of law. Economic, social and ecological sustainability will be achieved – if at all – by a complex series of rules of law that are capable of enforcement so as to ensure compliance with them. To what extent do these rules of law reflect the principle of the rule of law? Is the principle of the rule of law the formally unstated value that is expected to underpin the legal system or is it the normative predicate that directs the legal system both vertically and horizontally? Is sustainability an aspirational value or a normative predicate according to which the environment and its resources are managed? Let us deal sequentially with these issues by reviewing a number of examples that demonstrate the relationship between environmental governance and the rule of law.

Environmental pollution from shipbreaking industry : international law and national legal response

The international legal regime on shipbreaking is in its formative years. At the international level, the shipbreaking industry is partially governed by the Basel Convention on the Control of Transboundary Movements of Hazardous Wastes and their Disposal. However, how far this convention will be applicable for all aspects of transboundary movement of end-of-life ships is still, at least in the view of some scholars, a debatable issue. Against this backdrop, the International Maritime Organisation (IMO) has adopted a new, legally binding convention for shipbreaking. There is a rising voice from the developing countries that the convention is likely to impose more obligations on recycling facilities in the developing countries than on shipowners from rich nations. This may be identified as a clear derogation from the globally recognized international environmental law principle of common but differentiated treatment. This article will examine in detail major international conventions regulating transboundary movement and environmentally sound disposal of obsolete ships, as well as the corresponding laws of Bangladesh for implementing these conventions in the domestic arena. Moreover this article will examine in detail the recently adopted IMO Ship Recycling Convention.

Mathematical modelling of controlled drug release from polymer micro-spheres : incorporating the effects of swelling, diffusion and dissolution via moving boundary problems

Controlled drug delivery is a key topic in modern pharmacotherapy, where controlled drug delivery devices are required to prolong the period of release, maintain a constant release rate, or release the drug with a predetermined release profile. In the pharmaceutical industry, the development process of a controlled drug delivery device may be facilitated enormously by the mathematical modelling of drug release mechanisms, directly decreasing the number of necessary experiments. Such mathematical modelling is difficult because several mechanisms are involved during the drug release process. The main drug release mechanisms of a controlled release device are based on the device’s physiochemical properties, and include diffusion, swelling and erosion. In this thesis, four controlled drug delivery models are investigated. These four models selectively involve the solvent penetration into the polymeric device, the swelling of the polymer, the polymer erosion and the drug diffusion out of the device but all share two common key features. The first is that the solvent penetration into the polymer causes the transition of the polymer from a glassy state into a rubbery state. The interface between the two states of the polymer is modelled as a moving boundary and the speed of this interface is governed by a kinetic law. The second feature is that drug diffusion only happens in the rubbery region of the polymer, with a nonlinear diffusion coefficient which is dependent on the concentration of solvent. These models are analysed by using both formal asymptotics and numerical computation, where front-fixing methods and the method of lines with finite difference approximations are used to solve these models numerically. This numerical scheme is conservative, accurate and easily implemented to the moving boundary problems and is thoroughly explained in Section 3.2. From the small time asymptotic analysis in Sections 5.3.1, 6.3.1 and 7.2.1, these models exhibit the non-Fickian behaviour referred to as Case II diffusion, and an initial constant rate of drug release which is appealing to the pharmaceutical industry because this indicates zeroorder release. The numerical results of the models qualitatively confirms the experimental behaviour identified in the literature. The knowledge obtained from investigating these models can help to develop more complex multi-layered drug delivery devices in order to achieve sophisticated drug release profiles. A multi-layer matrix tablet, which consists of a number of polymer layers designed to provide sustainable and constant drug release or bimodal drug release, is also discussed in this research. The moving boundary problem describing the solvent penetration into the polymer also arises in melting and freezing problems which have been modelled as the classical onephase Stefan problem. The classical one-phase Stefan problem has unrealistic singularities existed in the problem at the complete melting time. Hence we investigate the effect of including the kinetic undercooling to the melting problem and this problem is called the one-phase Stefan problem with kinetic undercooling. Interestingly we discover the unrealistic singularities existed in the classical one-phase Stefan problem at the complete melting time are regularised and also find out the small time behaviour of the one-phase Stefan problem with kinetic undercooling is different to the classical one-phase Stefan problem from the small time asymptotic analysis in Section 3.3. In the case of melting very small particles, it is known that surface tension effects are important. The effect of including the surface tension to the melting problem for nanoparticles (no kinetic undercooling) has been investigated in the past, however the one-phase Stefan problem with surface tension exhibits finite-time blow-up. Therefore we investigate the effect of including both the surface tension and kinetic undercooling to the melting problem for nanoparticles and find out the the solution continues to exist until complete melting. The investigation of including kinetic undercooling and surface tension to the melting problems reveals more insight into the regularisations of unphysical singularities in the classical one-phase Stefan problem. This investigation gives a better understanding of melting a particle, and contributes to the current body of knowledge related to melting and freezing due to heat conduction.

Research supervision of international students in engineering and information technology disciplines (Resources)

This report provides an overview of the results of a collaborative research project titled "A model for research supervision of international students in engineering and information technology disciplines". This project aimed to identify factors influencing the success of culturally and linguistically diverse (CALD) higher degree research (HDR) students in the fields of Engineering and Information Technology at three Australian Universities: Queensland University of Technology, The University of Western Australia and Curtin University.

Designing an information accountability framework for eHealth

This tutorial is primarily based on the IEEE eHealth technical committee Newsletter published in March 2013. Its main focus is on information privacy management in eHealth through information accountability. The tutorial consists of three main aspects of a proposed information accountability framework for eHealth, namely, social aspects, technical aspects and legal aspects. Following a brief introduction of the problem domain and context, we present the tutorial in these three main components. The length of the tutorial is intended to be half a day.

Private lawyers in contemporary society : Australia

Admission to practice law in Australia falls under the general supervisory power of supreme court judges in the various jurisdictions. The degree of supervision varies among jurisdictions, but the judiciary generally is responsible for setting the educational requirements for admission. A variety of admission boards perform a number of administrative and supervisory functions; for example, determining whether a particular law school's degree satisfies educational requirements for admission...

Engineering the fitness of older patients for chemotherapy : an exploration of Comprehensive Geriatric Assessment in practice

Clinicians often report that currently available methods to assess older patients, including standard clinical consultations, do not elicit the information necessary to make an appropriate cancer treatment recommendation for older cancer patients. An increasingly popular way of assessing the potential of older patients to cope with chemotherapy is a Comprehensive Geriatric Assessment. What constitutes Comprehensive Geriatric Assessment, however, is open to interpretation and varies from one setting to another. Furthermore, Comprehensive Geriatric Assessment’s usefulness as a predictor of fitness for chemotherapy and as a determinant of actual treatment is not well understood. In this article, we analyse how Comprehensive Geriatric Assessment was developed for use in a large cancer service in an Australian capital city. Drawing upon Actor–Network Theory, our findings reveal how, during its development, Comprehensive Geriatric Assessment was made both a tool and a science. Furthermore, we briefly explore the tensions that we experienced as scholars who analyse medico-scientific practices and as practitioner–designers charged with improving the very tools we critique. Our study contributes towards geriatric oncology by scrutinising the medicalisation of ageing, unravelling the practices of standardisation and illuminating the multiplicity of ‘fitness for chemotherapy’.

Importance of bearing porosity in engineering and natural lubrication

The multilamellar structure of phospholipids, i.e. the surface amorphous layer (SAL) that covers the natural surface of articular cartilage, and hexagonal boron nitride (h-BN) on the surface of metal porous bearings are two prominent examples of the family of layered materials that possess the ability to deliver lamellar lubrication. This chapter presents the friction study that was conducted on the surfaces of cartilage and the metal porous bearing impregnated with oil (first generation) and with oil + h-BN (second generation). The porosity of cartilage is around 75% and those of metal porous bearings were 15–28 wt%. It is concluded that porosity is a critical factor in facilitating the excellent tribological properties of both articular cartilage and the porous metal bearings studied.

The politics and poetics of coexistence : experiments at the intersection of art and environmental engineering

This research project explores how interdisciplinary art practices can provide ways for questioning and envisaging alternative modes of coexistence between humans and the non-humans who together, make up the environment. As a practiceled project, it combines a body of creative work (50%) and this exegesis (50%). My interdisciplinary artistic practice appropriates methods and processes from science and engineering and merges them into artistic contexts for critical and poetic ends. By blending pseudo-scientific experimentation with creative strategies like visual fiction, humour, absurd public performance and scripted audience participation, my work engages with a range of debates around ecology. This exegesis details the interplay between critical theory relating to these debates, the work of other creative practitioners and my own evolving artistic practice. Through utilising methods and processes drawn from my prior career in water engineering, I present an interdisciplinary synthesis that seeks to promote improved understandings of the causes and consequences of our ecological actions and inactions.

Effects of introducing an interactive teaching and learning activity (TLA) in the engineering classroom

This research study examines qualitatively and quantitatively the influence of introducing an activity in the traditional engineering classroom. It studies instances of active learning and its relationship with the student learning outcomes. The primary purpose of this study was to compare the learning outcomes of students who were involved in an active TLA with those students who were not, instead they learned under traditional teaching and studying approaches. I present the argument that the introduction of a TLA in class stimulates student engagement bringing enormous benefits to student learning. The outcomes of this study were measured using qualitative and quantitative data to evaluate the levels of student engagement, achievement and satisfaction in the terms of Intended Learning Outcomes (ILOs). Results indicate that students held positive attitude towards the activities in class and also, that a positive link between TLA, learning approach and learning outcome exist. It also provides insights about the potential benefits of active learning when compared with traditional, passive and teacher-centred methods of teaching & learning.