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(2004)Journal ArticleIn this article we present the concept of a FPGA-based GPS receiver architecture with the aim of providing a framework for investigating new receiver architectures for current and upcoming GNSS standards. This development system facilitates researchers to prove new receiver concepts using real signals, which nowadays can only be simulated using tools such as Matlab. One will be able to work with the satellites as soon as they are operational, rather than having to wait for the availability of commercial products. The system allows individual development of signal processing solutions for base-band processing. A soft-core processor implements higher layer services that provide data to the user.
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(1995)Journal ArticleTwo types of Bi-2212 single crystals, one type having a low T c and the other having a high T¢ were annealed in air at different temperatures over the range 450°C to 750°C followed by furnace cooling. The transition temperature of the crystals with low T c (~ 56 K) increased with increase of annealing temperature, while the crystals with high Tc (~ 91 K) had just the opposite behaviour under the same annealing conditions. It is indicated that the quality of as-grown crystal has a significant effect on the superconducting properties of the annealed crystal. The c-axis values for both types of crystals decreased with increase of annealing temperature. According to the relationship between c-axis values and the oxygen content, our results confirmed the existence of a dome-shaped curve of T¢ with carrier concentration in Bi-2212 single crystal similar to that in Bi-2212 compound reported previously by Groen and de Leeuw [Physica C 159 (1989) 417]. By studying the increase of annealing time at a fixed temperature of 650°C, T¢ and ATe were found to change very little for both types of crystals. Thus, T c and AT~ were more sensitive to annealing temperature than to annealing time. XRD, SEM and EDS revealed that a small quantity of powder phase appeared after annealing at temperatures above 500°C for both types of crystals. This powder phase had the Bi-2212 composition, which indicated that the integrity of the Bi-2212 single crystals was significantly degraded by the annealing process.
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(2008)Journal ArticleCreating meaningful active learning experiences can be a significant and sometimes comical challenge for a new lecturer. In this article, I describe my own active learning experience as I attempted to break down the separation between tutorials and lectures that was typical of the university education I experienced. The adoption of a sustainability framework for decision-making processes associated with major infrastructure developments in the Australia water industry is a recent innovation which has provided a convenient vehicle for supporting this change. A case study drawn from a fourth year Environmental Engineering Practice class is used to illustrate how the framework can be applied to provide new and relevant curriculum. The overall intent of this paper is to support new lecturers on their own journeys into teaching, and perhaps to remind their experienced mentors of a particular challenge their colleagues face at the beginning.
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(2008)Journal ArticleA revised methodology for calculating ecological footprints is proposed. The method considers anthropogenic disturbances at a finer level of geographical desegregation than previous methods; instead of a single national land area it considers 1408 smaller regions within Australia. It also addresses a previous gap in disturbance based ecological footprint calculation, that is, the exclusion of ecotoxic emissions. The method is described and illustrated using a case study. The resulting ecological footprint is larger than previous calculations, but it avoids a current methodological problem in which the energy used to treat exhaust gases or wastewaters increases the ecological footprint of communities without any corresponding benefit associated with reduced emissions to the environment.
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(2004)Journal ArticleLife Cycle Assessment (LCA) is useful as an information tool for the examination of alternative future scenarios for strategic planning. Developing a life cycle assessment for a large water and wastewater system involves making methodological decisions about the level of detail which is retained through different stages of the process. In this article we discuss a methodology tailored to strategic planning needs which retains a high degree of model segmentation in order to enhance modeling of a large, complex system. This is illustrated by a case study of Sydney Water, which is Australia’s largest water service provider. A prospective LCA was carried out to examine the potential environmental impacts of Sydney Water’s total operations in the year 2021. To our knowledge this is the first study to create an LCA model of an integrated water and wastewater system with this degree of complexity. A “base case” system model was constructed to represent current operating assets as augmented and upgraded to 2021. The base case results provided a basis for the comparison of alternative future scenarios and for conclusions to be drawn regarding potential environmental improvements. The scenarios can be roughly classified in two categories: (1) options which improve the environmental performance across all impact categories and (2) options which improve one indicator and worsen others. Overall environmental improvements are achieved in all categories by the scenarios examining increased demand management, energy efficiency, energy generation, and additional energy recovery from biosolids. The scenarios which examined desalination of seawater and the upgrades of major coastal sewage treatment plants to secondary and tertiary treatment produced an improvement in one environmental indicator but deteriorations in all the other impact categories, indicating the environmental tradeoffs within the system. The desalination scenario produced a significant increase in greenhouse gas emissions due to coalfired electricity generation for a small increase in water supply. Assessment of a greenfield scenario incorporating water demand management, on-site treatment, local irrigation, and centralized biosolids treatment indicates significant environmental improvements are possible relative to the assessment of a conventional system of corresponding scale.
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(2008)Journal ArticleCommercial feedlots for beef cattle finishing are potential sources of a range of trace chemicals which have human health or environmental significance. To ensure adequate protection of human and environmental health from exposure to these chemicals, the application of effective manure and effluent management practices is warranted. The Australian meat and livestock industry has adopted a proactive approach to the identification of best management practices. Accordingly, this review was undertaken to identify key chemical species that may require consideration in the development of guidelines for feedlot manure and effluent management practices in Australia. Important classes of trace chemicals identified include steroidal hormones, antibiotics, ectoparasiticides, mycotoxins, heavy metals and dioxins. These are described in terms of their likely sources, expected concentrations and public health or environmental significance based on international data and research. Androgenic hormones such as testosterone and trenbolone are significantly active in feedlot wastes, but they are poorly understood in terms of fate and environmental implications. The careful management of residues of antibiotics including virginiamycin, tylosin and oxytetracycline appears prudent in terms of minimising the risk of potential public health impacts from resistant strains of bacteria. Good management of ectoparasiticides including synthetic pyrethroids, macrocyclic lactones, fluazuron, and amitraz is important for the prevention of potential ecological implications, particularly towards dung beetles. Very few of these individual chemical contaminants have been thoroughly investigated in terms of concentrations, effects and attenuation in Australian feedlot wastes. © 2007 Elsevier Ltd. All rights reserved.
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(2007)Journal ArticleA new calculation of the Ecological Footprint (EF) of a water provider addresses limitations in the previous methodology by regionalising a previously national input-output model, and determining the area of disturbance caused by environmental toxicants not considered in the traditional EF model. In a first step, the regional input-output model determines indirect effects of water services activities in the form of point sources of pollutants. Accuracy is improved by hybridisation using “process data” to account for the direct environmental burden of the water service. The accuracy of the input-output model is improved by reconciling data sources; calibrating concordance tables and employing optimisation techniques to deal with conflicting data sources. The second step involves a nested fate model, which follows the fate of the point source emissions at several spatial scales. The final output provides an indication of the direct and indirect burden connected with the water business, throughout its entire upstream supply chains. This proposed EF methodology improves on previous EF methodologies by avoiding exclusive reliance on national average data, and by including toxicants in a disturbance-based calculation analogous to the established inclusion of greenhouse gases in EF, making it more comprehensive. It is hoped that the additional detail and comprehensiveness will make the new method a more effective environmental reporting and communications tool for the Australian water industry. This generic approach to environmental reporting may potentially be applied to other economic activities.
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(2006)Journal ArticleIn this article we discuss the application of strategic planning tools in the Australian water industry and a framework for assessing the sustainability of new investments in water cycle management. Created in a research project partly funded by the Water Services Association of Australia, the Sustainability Framework is based on taking the best of current strategic planning and sustainability assessment approaches, including appropriate levels of interaction with public and government stakeholders. It embraces recent developments in the application of life cycle assessment and other information tools. The intent is to deliver a guide which provides for both analytical and participatory aspects of sustainability assessment.