Physical Sciences and Mathematics Commons^™

Development Of An In-Field Voltammetric Method For The Determination Of Barium, Samantha N. Ridgway

Theses : Honours

This work presents a reliable, cost-effective, rapid and infield voltammetric method for the detection of barium. The optimized method consists of an ultrathin mercury film deposited in-situ on a glassy carbon electrode in 0.02 M potassium chloride without deoxygenation; a deposition potential of -2500 mV, pulse height = 50 mV, step duration = 10 ms and a scan rate of 100 mV/s using differential pulse anodic stripping voltammetry (DP-ASV).

The linear working range for barium was determined to be 5 – 80 μg/L (r² = 0.997), and limit of detection (LOD) was 1.6 μg/L, for 30 sec deposition time. …

Boundaries Of Governance: Social Responsibility In Mining In Western Australia, Gemma L. Broderick

Theses: Doctorates and Masters

This research investigated the boundaries of governance of social responsibility in three multinational mining organisations based in Perth, Western Australia. The mining industry has economic, environmental and social impacts, both positive and negative. While most of the attention of the media and supporters in government seems to focus on the positive impacts, a growing concern regarding the social implications of mining is clearly evident in public discourse and the academic literature. In response to public concern, the mining industry has adopted terms such as ‘sustainability’, ‘sustainable development’, ‘social licence to operate’ and ‘social responsibility’. Such phrases are widely used in …

Compositions, Logratios And Geostatistics: An Application To Iron Ore, Clint Ward

Theses: Doctorates and Masters

Common implementations of geostatistical methods, kriging and simulation, ignore the fact that geochemical data are usually reported in weight percent, sum to a constant, and are thus compositional in nature. The constant sum implies that rescaling has occurred and this can be shown to produce spurious correlations. Compositional geostatistics is an approach developed to ensure that the constant sum constraint is respected in estimation while removing dependencies on the spurious correlations. This study tests the applicability of this method against the commonly implemented ordinary cokriging method. The sample data are production blast cuttings analyses drawn from a producing iron ore …

Investigation Of Interferences And Development Of Pre-Treatment Methods For Arsenic Analysis By Anodic Stripping Voltammetry, Paul Lewtas

Theses: Doctorates and Masters

Contamination of drinking water is a serious health issue in many developing countries and there is a recognised need for low cost portable systems that are capable of analysing drinking water down to low ppb levels. Anodic Stripping Voltammetry (ASV) instruments meet these requirements but suffer interferences from other species which may also be present in the sample, particularly organics, other metals and sulfides. The last of these has received surprisingly little attention in the literature, despite being a proven interferent.

This study investigates the impact of each of these interference types, as well as a number of traditional and …

An Appraisal Of Experiences Of Climate Change And Adaptive Response To Heat Stress By Farmers In Rural Ghana, Kwasi Frimpong

Theses: Doctorates and Masters

With the increase in average global temperatures, heat-related illnesses and deaths have unfolded as occupational and health issues. Periods of high to extreme temperatures are becoming more common and are a leading cause of weather-related deaths in many countries. In agricultural settings of African countries, heat stress is a major concern as many smallholder farmers work outdoors with limited access to cooling systems even in their resting and living environments. This study, conducted in the Bawku East part of Northern-East Ghana in 2013, examines, in the context of climate change, the trends and impacts of heat stress on smallholder farmers, …

Judging Dread: A Quantitative Investigation Of Affect, Psychometric Dread And Risk Consequence, Melvyn Griffiths

Theses: Doctorates and Masters

Risk is generally understood as a product of the likelihood and consequence of an event. However, the way in which estimations of consequences are formed is unclear due to the complexities of human perception. In particular, the influence of Affect, defined as positive or negative qualities subjectively assigned to stimuli, may skew risk consequence judgements. Thus a clearer understanding of the role of Affect in risk consequence estimations has significant implications for risk management, risk communication and policy formulation.

In the Psychometric tradition of risk perception, Affect has become almost synonymous with the concept of Dread, despite Dread being measured …

Accessibility Of Thai University Websites: Awareness, Barriers And Drivers For Accessible Practice, Rattanavalee Maisak

Theses: Doctorates and Masters

Governments and organizations have to respond to a range of legislative and policy initiatives intended to promote equal opportunity for all. The Thai government has passed a number of laws which aim to protect its citizens from discrimination and from breaches of their human rights by government departments and agencies. The Persons with Disabilities Education Act B.E. 2551 (2008) and the Thailand Information and Communication Technology (ICT) Policy Framework (2011-2020) required government agencies to delivery equal education and access to online information for all Thais. Most Thai universities receive government subsidies, and therefore have an obligation to contribute to national …

Wedge Failure Analysis Of Anchored Rock Slopes Subjected To Surcharge And Seismic Loads, Yan Kou

Theses: Doctorates and Masters

Slope stability in mining and civil engineering projects is always a problem of great concern. Because the rock mass behavior is significantly governed by the presence of joints or other discontinuities, several types of slope failure, such as plane failure, wedge failure, toppling failure, buckling failure and circular failure, are often observed. The present work focuses on the study of the wedge failure, which occurs as sliding of a mass of rock on two intersecting planes, generally discontinuity planes.

Recently, the factor of safety of rock slopes against the wedge failure has been studied in a number of investigations under …

Characterising The Effect Of A Novel Optical Delay Line And Light Sources On The Resolvability Of Time Domain Optical Coherence Tomography, Paul V. Jansz

Theses: Doctorates and Masters

Optical coherence tomography (OCT) is a reflection based imaging technique, with numerous applications, initially in medical diagnostics. Unlike ultrasound, another reflection imaging technique, OCT relies on light scattering in samples, low coherence near- infrared interferometry, and graphical image construction, to acquire 2D and 3D reflectogram images. OCT has resolution an order of magnitude greater than ultrasound, but its depth penetration is less than a few millimetres.

Axial resolution is a critical parameter in determining whether OCT can be used to resolve specific features in a sample image. Typically, measures of resolution have been attributed only to the light source’s characteristics, …

Intelligent Network Intrusion Detection Using An Evolutionary Computation Approach, Samaneh Rastegari

Theses: Doctorates and Masters

With the enormous growth of users' reliance on the Internet, the need for secure and reliable computer networks also increases. Availability of effective automatic tools for carrying out different types of network attacks raises the need for effective intrusion detection systems.

Generally, a comprehensive defence mechanism consists of three phases, namely, preparation, detection and reaction. In the preparation phase, network administrators aim to find and fix security vulnerabilities (e.g., insecure protocol and vulnerable computer systems or firewalls), that can be exploited to launch attacks. Although the preparation phase increases the level of security in a network, this will never completely …

Intensity Based Interrogation Of Optical Fibre Sensors For Industrial Automation And Intrusion Detection Systems, Gary Andrew Allwood

Theses: Doctorates and Masters

In this study, the use of optical fibre sensors for intrusion detection and industrial automation systems has been demonstrated, with a particular focus on low cost, intensity-based, interrogation techniques. The use of optical fibre sensors for intrusion detection systems to secure residential, commercial, and industrial premises against potential security breaches has been extensively reviewed in this thesis. Fibre Bragg grating (FBG) sensing is one form of optical fibre sensing that has been underutilised in applications such as in-ground, in-fence, and window and door monitoring, and addressing that opportunity has been a major goal of this thesis. Both security and industrial …

Secure Portable Execution And Storage Environments: A Capability To Improve Security For Remote Working, Peter James

Theses: Doctorates and Masters

Remote working is a practice that provides economic benefits to both the employing organisation and the individual. However, evidence suggests that organisations implementing remote working have limited appreciation of the security risks, particularly those impacting upon the confidentiality and integrity of information and also on the integrity and availability of the remote worker’s computing environment. Other research suggests that an organisation that does appreciate these risks may veto remote working, resulting in a loss of economic benefits. With the implementation of high speed broadband, remote working is forecast to grow and therefore it is appropriate that improved approaches to managing …

Improving Energy Efficiency And Quality Of Service In An Integrated Wireless-Optical Broadband Access Network, Maha Shihab Ahmed

Theses: Doctorates and Masters

Exponential growth in the volume of wireless data, boosted by the growing popularity of mobile devices such as smart phones and tablets, is forcing telecommunication industries to rethink network design, and focus on developing high capacity mobile broadband networks. Accordingly, researchers have undertaken developmental work for an integrated wireless-optical broadband access network (WOBAN). Passive optical networks (PONs) and fourth generation (4G) wireless networks are two major candidate technologies for the WOBAN. PON is a wired access technology, well-known for its high capacity, whereas 4G is a wireless broadband access technology, popular for its ease of deployment and ability to offer …