Performance characterization of VGCF/epoxy nanocomposite sensors under static load cycles and in static structural health monitoring

Compared to conventional metal-foil strain gauges, nanocomposite piezoresistive strain sensors have demonstrated high strain sensitivity and have been attracting increasing attention in recent years. To fulfil their ultimate success, the performance of vapor growth carbon fiber (VGCF)/epoxy nanocomposite strain sensors subjected to static cyclic loads was evaluated in this work. A strain-equivalent quantity (resistance change ratio) in cantilever beams with intentionally induced notches in bending was evaluated using the conventional metal-foil strain gauges and the VGCF/epoxy nanocomposite sensors. Compared to the metal-foil strain gauges, the nanocomposite sensors are much more sensitive to even slight structural damage. Therefore, it was confirmed that the signal stability, reproducibility, and durability of these nanocomposite sensors are very promising, leading to the present endeavor to apply them for static structural health monitoring.

Approaches to access control under uncertainty

The ultimate goal of an access control system is to allocate each user the precise level of access they need to complete their job - no more and no less. This proves to be challenging in an organisational setting. On one hand employees need enough access to the organisation’s resources in order to perform their jobs and on the other hand more access will bring about an increasing risk of misuse - either intentionally, where an employee uses the access for personal benefit, or unintentionally, through carelessness or being socially engineered to give access to an adversary. This thesis investigates issues of existing approaches to access control in allocating optimal level of access to users and proposes solutions in the form of new access control models. These issues are most evident when uncertainty surrounding users’ access needs, incentive to misuse and accountability are considered, hence the title of the thesis. We first analyse access control in environments where the administrator is unable to identify the users who may need access to resources. To resolve this uncertainty an administrative model with delegation support is proposed. Further, a detailed technical enforcement mechanism is introduced to ensure delegated resources cannot be misused. Then we explicitly consider that users are self-interested and capable of misusing resources if they choose to. We propose a novel game theoretic access control model to reason about and influence the factors that may affect users’ incentive to misuse. Next we study access control in environments where neither users’ access needs can be predicted nor they can be held accountable for misuse. It is shown that by allocating budget to users, a virtual currency through which they can pay for the resources they deem necessary, the need for a precise pre-allocation of permissions can be relaxed. The budget also imposes an upper-bound on users’ ability to misuse. A generalised budget allocation function is proposed and it is shown that given the context information the optimal level of budget for users can always be numerically determined. Finally, Role Based Access Control (RBAC) model is analysed under the explicit assumption of administrators’ uncertainty about self-interested users’ access needs and their incentives to misuse. A novel Budget-oriented Role Based Access Control (B-RBAC) model is proposed. The new model introduces the notion of users’ behaviour into RBAC and provides means to influence users’ incentives. It is shown how RBAC policy can be used to individualise the cost of access to resources and also to determine users’ budget. The implementation overheads of B-RBAC is examined and several low-cost sub-models are proposed.

Dynamic performance characteristics of an innovative Hybrid Composite Floor Plate System under human-induced loads

This study explored the dynamic performance of an innovative Hybrid Composite Floor Plate System (HCFPS), composed of Polyurethane (PU) core, outer layers of Glass–fibre Reinforced Cement (GRC) and steel laminates at tensile regions, using experimental testing and Finite Element (FE) modelling. Experimental testing included heel impact and walking tests for 3200 mm span HCFPS panels. FE models of the HCFPS were developed using the FE program ABAQUS and validated with experimental results. HCFPS is a light-weight high frequency floor system with excellent damping ratio of 5% (bare floor) due to the central PU core. Parametric studies were conducted using the validated FE models to investigate the dynamic response of the HCFPS and to identify characteristics that influence acceleration response under human induced vibration in service. This vibration performance was compared with recommended acceptable perceptibility limits. The findings of this study show that HCFPS can be used in residential and office buildings as a light-weight floor system, which does not exceed the perceptible thresholds due to human induced vibrations.

Soil-pile interaction in deep layered marine sediment under seismic excitation

Under seismic loads neither the response of the pile nor the response of ground are independent of each other, contrary what is normally assumed. In seismic design of buildings, dynamic response of a structure is determined by assuming a fixed base on sub-grade and neglecting the physical interaction between foundation and soil profile in which it is embedded. However, the seismic response of pile foundations in vibration sensitive soil profiles is significantly affected by the behaviour of supporting soil. This research uses validated Finite Element techniques to simulate the seismic behaviour of pile foundations embedded in multilayered vibration sensitive soils.

Arbitration proceeding – determination of “market price” – subpoena under Commercial Arbitration Act 1990 s 17

AGL Wholesale Gas Ltd v Origin Energy Ltd [2008] QCA 366 involved an appeal against the setting aside of paragraphs of a subpoena issued under s 17 of the Commercial Arbitration Act 1990 (Qld). The Court was satisfied that even if the documents were of “apparent relevance” to the subject matter of the proceedings, it would nevertheless be oppressive to require their production.

Setting aside default judgment - whether judgment regularly or irregularly entered - service under Corporations Act 2001 (Cth) s109X(1) - requirements for affadavit of service

In Hill v Robertson Suspension Systems Pty Ltd [2009] QDC 165 McGill DCJ considered the procedural requirements for the service of originating process on a company, and for proving that service for the purpose of obtaining default judgment.The judge’s views adopt a strict and technical construction of the requirements for an affidavit of service under r 120(1)(b). Though clearly obiter, they may well affect the approach taken on applications to enter or set aside default judgments in the lower courts. Pending further judicial consideration of the issue, it is suggested the prudent course is to ensure that the deponent of an affidavit for service effected under s 109X(1)(a) of the Act deposes not only to the location of the registered office of the company but also, at a minimum, provides the source of that information.

Stress distribution of CFRP strengthened steel hollow sections under tension

Carbon fibre reinforced polymer (CFRP) sheets have many outstanding properties such as high strength, high elastic modulus, light weight and good durability which are made them a suitable alternative for steel in strengthening work. This paper describe the ultimate load carrying capacity of steel hollow sections at effective bond length in terms of its cross sectional area and the stress distribution within bond region for different layers CFRP. It was found that depending on their size and orientation of uni- directional CFRP layers, the ultimate tensile load was different. Along with these tests, non linear finite element analysis was also performed to validate the ultimate load carrying capacity depending on their cross sections. The predicted ultimate loads from FE analysis are found very close to the laboratory test results. The validated model has been used to determine the stress distribution at bond joint for different orientation of CFRP. This research shows the effect of stress distribution and suitable wrapping layer to be used for the strengthening of steel hollow sections in tension.

A Process and Outcome Evaluation of the Under the Limit (UTL) Therapeutic Drink Driving Program for Recidivist and High Range Offenders

Drink driving is a major public health issue and this report examines the experiences of convicted offenders who participated in an established drink driving rehabilitation program Under the Limit (UTL). Course completers were surveyed at least three months after they had finished the 11-week UTL course. The aim of this study was to examine whether the UTL program reduced the level of alcohol consumption either directly as a result of participation in the UTL drink driving program or through increased use of community alcohol program by participants. The research involved a self-report outcome evaluation to determine whether the self-reported levels of alcohol use after the course had changed from the initial alcohol use reported by offenders. The findings are based on the responses of 30 drink-driving offenders who had completed the UTL program (response rate: 20%). While a process evaluation was proposed in the initial application, the low response rate meant that this follow up research was not feasible. The response rate was low for two reasons, it was difficult to: recruit participants who consented to follow up, and subsequently locate and survey those who had consented to involvement.

Numerical studies of load bearing LSF walls under realistic design fire conditions

Fire safety of light gauge steel frame (LSF) stud walls is important in the design of buildings. Currently LSF walls are increasingly used in the building industry, and are usually made of cold-formed and thin-walled steel studs that are fire-protected by two layers of plasterboard on both sides. Many experimental and numerical studies have been undertaken to investigate the fire performance of load bearing LSF walls under standard fire conditions. However, the standard time-temperature curve does not represent the fire load present in typical residential and commercial buildings that include considerable amount of thermoplastic materials. Real building fires are unlikely to follow a standard time-temperature curve. However, only limited research has been undertaken to investigate the fire performance of load bearing LSF walls under realistic design fire conditions. Therefore in this research, finite element thermal models of the traditional LSF wall panels without cavity insulation and the new LSF composite wall panels were developed to simulate their fire performance under recently developed realistic design fire curves. Suitable thermal properties were proposed for plasterboards and insulations based on laboratory tests and literature review. The developed models were then validated by comparing their thermal performance results with available results from realistic design fire tests, and were later used in parametric studies. This paper presents the details of the developed finite element thermal models of load bearing LSF wall panels under realistic design fire time-temperature curves and the re-sults. It shows that finite element thermal models can be used to predict the fire performance of load bearing LSF walls with varying configurations of insulations and plasterboards under realistic design fires. Failure times of load bearing LSF walls were also predicted based on the results from finite element thermal analyses.

Rod and cone pathway signaling and interaction under mesopic illumination

This study investigates the time-course and post-receptoral pathway signaling of photoreceptor interactions when the rod (R) and three cone (L, M, S) photoreceptor classes contribute to mesopic vision. A four-primary photostimulator independently controls photoreceptor activity in human observers. The first experiment defines the temporal adaptation response of receptoral (L-, S-cone, rod) and post-receptoral (LMS, LMSR,+L-M) signaling and interactions. Here we show that nonopponent cone-cone interactions (L-cone, LMS, LMSR) have monophasic temporal response patterns whereas opponent signals (+L-M, S-cone) show biphasic response patterns with slower recovery. By comparison, rod-cone interactions with nonopponent signals have faster adaptation responses and reduced sensitivity loss whereas opponent rod-cone interactions are small or absent. Additionally, the rod-rod interaction differs from these interaction types and acts to increase rod sensitivity due to temporal summation but with a slower time course. The second experiment shows that the temporal profile of the rod signal alters the relative rod contributions to the three primary post-receptoral pathways. We demonstrate that rod signals generate luminance (þLþM) signals mediated via the MC pathway with all rod temporal profiles and chromatic signals (L/LþM, S/LþM) in both the PC and KC pathways with durations .75 ms. Thus, we propose that the change in relative weighting of rod signals within the post-receptoral pathways contributes to the sensitivity and temporal response of rod and cone pathway signaling and interactions.

The determinants of demand for private health insurance under Medicare

Since the introduction of Medicare in 1984, the proportion of the Australian population with private health insurance has declined considerably. Insurance for health care consumption is compulsory for the public health sector but optional for the private health sector. In this paper, we explore a number of important issues in the demand for private health insurance in Australia. The socio-economic variables which influence demand are examined using a binary logic model. A number of simulations are performed to highlight the influence and relative importance of various characteristics such as age, income, health status and geographical location on demand. A number of important policy issues in the private health insurance market are highlighted. First, evidence is provided of adverse selection in the private health insurance pool, second, the notion of the wealthy uninsured is refuted, and finally it is confirmed that there are significant interstate differences in the demand for private health insurance.

Project management under uncertainty

Morris' (1986) analysis of the factors affecting project success and failure is considered in relation to the psychology of judgement under uncertainty. A model is proposed whereby project managers may identify the specific circumstances in which human decision-making is prone to systematic error, and hence may apply a number of de-biasing techniques.

Preventing the selection of “deaf embryos” under the Human Fertilisation and Embryology Act 2008 : problematizing disability?

Section 14(4) of the Human Fertilisation and Embryology Act 2008 imposes – within the general licensing conditions listed in the Human Fertilisation and Embryology Act 1990 – a prohibition to prevent the selection and implantation of embryos for the purpose of creating a child who will be born with a “serious disability.” This article offers a perspective that demonstrates the problematic nature of the consultation, review, and legislative reform process surrounding s 14(4). The term “serious disability” is not defined within the legislation, but we highlight the fact that s 14(4) was passed with the case of selecting deaf children in mind. We consider some of the literature on the topic of disability and deafness, which, we think, casts some doubt on the view that deafness is a “serious disability.” The main position we advance is that the lack of serious engagement with alternative viewpoints during the legislative process was unsatisfactory. We argue that the contested nature of deafness necessitates a more robust consultation process and a clearer explanation and defence of the normative position that underpins s 14(4).

Design of LSF wall studs under fire conditions

Cold-formed steel lipped channels are commonly used in LSF wall construction as load bearing studs with plasterboards on both sides. Under fire conditions, cold-formed thin-walled steel sections heat up quickly resulting in fast reduction in their strength and stiffness. Usually the LSF wall panels are subjected to fire from one side which will cause thermal bowing, neutral axis shift and magnification effects due to the development of non-uniform temperature distributions across the stud. This will induce an additional bending moment in the stud and hence the studs in LSF wall panels should be designed as a beam column considering both the applied axial compression load and the additional bending moment. Traditionally the fire resistance rating of these wall panels is based on approximate prescriptive methods. Very often they are limited to standard wall configurations used by the industry. Therefore a detailed research study is needed to develop fire design rules to predict the failure load and hence the failure time of LSF wall panels subject to non-uniform temperature distributions. This paper presents the details of an investigation to develop suitable fire design rules for LSF wall studs under non-uniform elevated temperature distributions. Applications of the previously developed fire design rules based on AISI design manual and Eurocode 3 Parts 1.2 and 1.3 to LSF wall studs were investigated in detail and new simplified fire design rules based on AS/NZS 4600 and Eurocode 3 Part 1.3 were proposed in the current study with suitable allowances for the interaction effects of compression and bending actions. The accuracy of the proposed fire design rules was verified by using the results from full scale fire tests and extensive numerical studies.