949 resultados para Higher temperatures


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Fire safety design of building structures has received greater attention in recent times due to continuing losses of properties and lives in fires. However, the structural behaviour of thin-walled cold-formed steel columns under fire conditions is not well understood despite the increasing use of light gauge steels in building construction. Cold-formed steel columns are often subject to local buckling effects. Therefore a series of laboratory tests of lipped and unlipped channel columns made of varying steel thicknesses and grades was undertaken at uniform elevated temperatures up to 700°C under steady state conditions. Finite element models of the tested columns were also developed, and their elastic buckling and nonlinear analysis results were compared with test results at elevated temperatures. Effects of the degradation of mechanical properties of steel with temperature were included in the finite element analyses. The use of accurately measured yield stress, elasticity modulus and stress-strain curves at elevated temperatures provided a good comparison of the ultimate loads and load-deflection curves from tests and finite element analyses. The commonly used effective width design rules and the direct strength method at ambient temperature were then used to predict the ultimate loads at elevated temperatures by using the reduced mechanical properties. By comparing these predicted ultimate loads with those from tests and finite element analyses, the accuracy of using this design approach was evaluated.

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We show that SiGe islands are transformed into nanoholes and rings by annealing treatments only and without Si capping. Rings are produced by a rapid flash heating at temperatures higher than the melting point of Ge, whereas nanoholes are produced by several minute annealing. The rings are markedly rich in Si with respect to the pristine islands, suggesting that the evolution path from islands to rings is driven by the selective dissolution of Ge occurring at high temperature.

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Higher-order thinking has featured persistently in the reform agenda for science education. The intended curriculum in various countries sets out aspirational statements for the levels of higher-order thinking to be attained by students. This study reports the extent to which chemistry examinations from four Australian states align and facilitate the intended higher-order thinking skills stipulated in curriculum documents. Through content analysis, the curriculum goals were identified for each state and compared to the nature of question items in the corresponding examinations. Categories of higher-order thinking were adapted from the OECD’s PISA Science test to analyze question items. There was considerable variation in the extent to which the examinations from the states supported the curriculum intent of developing and assessing higher-order thinking. Generally, examinations that used a marks-based system tended to emphasize lower-order thinking, with a greater distribution of marks allocated for lower-order thinking questions. Examinations associated with a criterion-referenced examination tended to award greater credit for higher-order thinking questions. The level of complexity of chemistry was another factor that limited the extent to which examination questions supported higher-order thinking. Implications from these findings are drawn for the authorities responsible for designing curriculum and assessment procedures and for teachers.

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Universities are more and more challenged by the emerging global higher education market, facilitated by advances in Information and Communication Technologies (ICT). This requires them to reconsider their mission and direction in order to function effectively and efficiently, and to be responsive to changes in their environment. In the face of increasing demands and competitive pressures, Universities like other companies, seek to continuously innovate and improve their performance. Universities are considering co-operating or sharing, both internally and externally, in a wide range of areas to achieve cost effectiveness and improvements in performance. Shared services are an effective model for re-organizing to reduce costs, increase quality and create new capabilities. Shared services are not limited to the Higher Education (HE) sector. Organizations across different sectors are adopting shared services, in particular for support functions such as Finance, Accounting, Human Resources and Information Technology. While shared services has been around for more than three decades, commencing in the 1970’s in the banking sector and then been adopted by other sectors, it is an under researched domain, with little consensus on the most fundamental issues even as basic as defining what shared services is. Moreover, the interest in shared services within Higher Education is a global phenomenon. This study on shared services is situated within the Higher Education Sector of Malaysia, and originated as an outcome resulting from a national project (2005 – 2007) conducted by the Ministry of Higher Education (MOHE) entitled "Knowledge, Information Communication Technology Strategic Plan (KICTSP) for Malaysian Public Higher Education"- where progress towards more collaborations via shared services was a key recommendation. The study’s primary objective was to understand the nature and potential for ICT shared services, in particular in the Malaysian HE sector; by laying a foundation in terms of definition, typologies and research agenda and deriving theoretically based conceptualisations of the potential benefits of shared services, success factors and issues of pursuing shared services. The study embarked on this objective with a literature review and pilot case study as a means to further define the context of the study, given the current under-researched status of ICT shared services and of shared services in Higher Education. This context definition phase illustrated a range of unaddressed issues; including a lack of common understanding of what shared services are, how they are formed, what objectives they full fill, who is involved etc. The study thus embarked on a further investigation of a more foundational nature with an exploratory phase that aimed to address these gaps, where a detailed archival analysis of shared services literature within the IS context was conducted to better understand shared services from an IS perspective. The IS literature on shared services was analysed in depth to report on the current status of shared services research in the IS domain; in particular definitions, objectives, stakeholders, the notion of sharing, theories used, and research methods applied were analysed, which provided a firmer base to this study’s design. The study also conducted a detailed content analysis of 36 cases (globally) of shared services implementations in the HE sector to better understand how shared services are structured within the HE sector and what is been shared. The results of the context definition phase and exploratory phase formed a firm basis in the multiple case studies phase which was designed to address the primary goals of this study (as presented above). Three case sites within the Malaysian HE sector was included in this analysis, resulting in empirically supported theoretical conceptualizations of shared services success factors, issues and benefits. A range of contributions are made through this study. First, the detailed archival analysis of shared services in Information Systems (IS) demonstrated the dearth of research on shared services within Information Systems. While the existing literature was synthesised to contribute towards an improved understanding of shared services in the IS domain, the areas that are yet under-developed and requires further exploration is identified and presented as a proposed research agenda for the field. This study also provides theoretical considerations and methodological guidelines to support the research agenda; to conduct better empirical research in this domain. A number of literatures based a priori frameworks (i.e. on the forms of sharing and shared services stakeholders etc) are derived in this phase, contributing to practice and research with early conceptualisations of critical aspects of shared services. Furthermore, the comprehensive archival analysis design presented and executed here is an exemplary approach of a systematic, pre-defined and tool-supported method to extract, analyse and report literature, and is documented as guidelines that can be applied for other similar literature analysis, with particular attention to supporting novice researchers. Second, the content analysis of 36 shared services initiatives in the Higher Education sector presented eight different types of structural arrangements for shared services, as observed in practice, and the salient dimensions along which those types can be usefully differentiated. Each of the eight structural arrangement types are defined and demonstrated through case examples, with further descriptive details and insights to what is shared and how the sharing occurs. This typology, grounded on secondary empirical evidence, can serve as a useful analytical tool for researchers investigating the shared services phenomenon further, and for practitioners considering the introduction or further development of shared services. Finally, the multiple case studies conducted in the Malaysian Higher Education sector, provided further empirical basis to instantiate the conceptual frameworks and typology derived from the prior phases and develops an empirically supported: (i) framework of issues and challenges, (ii) a preliminary theory of shared services success, and (iii) a benefits framework, for shared services in the Higher Education sector.

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In this paper we report a new neutron Compton scattering (NCS) measurement of the ground state single atom kinetic energy of polycrystalline beryllium at momentum transfers in the range 27}104 As ~1 and temperatures in the range 110}1150 K. The measurements have been made with the electron Volt spectrometer (eVS) at the ISIS facility and the measured kinetic energies are shown to be &10% higher than calculations made in the harmonic approximation.

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Robust hashing is an emerging field that can be used to hash certain data types in applications unsuitable for traditional cryptographic hashing methods. Traditional hashing functions have been used extensively for data/message integrity, data/message authentication, efficient file identification and password verification. These applications are possible because the hashing process is compressive, allowing for efficient comparisons in the hash domain but non-invertible meaning hashes can be used without revealing the original data. These techniques were developed with deterministic (non-changing) inputs such as files and passwords. For such data types a 1-bit or one character change can be significant, as a result the hashing process is sensitive to any change in the input. Unfortunately, there are certain applications where input data are not perfectly deterministic and minor changes cannot be avoided. Digital images and biometric features are two types of data where such changes exist but do not alter the meaning or appearance of the input. For such data types cryptographic hash functions cannot be usefully applied. In light of this, robust hashing has been developed as an alternative to cryptographic hashing and is designed to be robust to minor changes in the input. Although similar in name, robust hashing is fundamentally different from cryptographic hashing. Current robust hashing techniques are not based on cryptographic methods, but instead on pattern recognition techniques. Modern robust hashing algorithms consist of feature extraction followed by a randomization stage that introduces non-invertibility and compression, followed by quantization and binary encoding to produce a binary hash output. In order to preserve robustness of the extracted features, most randomization methods are linear and this is detrimental to the security aspects required of hash functions. Furthermore, the quantization and encoding stages used to binarize real-valued features requires the learning of appropriate quantization thresholds. How these thresholds are learnt has an important effect on hashing accuracy and the mere presence of such thresholds are a source of information leakage that can reduce hashing security. This dissertation outlines a systematic investigation of the quantization and encoding stages of robust hash functions. While existing literature has focused on the importance of quantization scheme, this research is the first to emphasise the importance of the quantizer training on both hashing accuracy and hashing security. The quantizer training process is presented in a statistical framework which allows a theoretical analysis of the effects of quantizer training on hashing performance. This is experimentally verified using a number of baseline robust image hashing algorithms over a large database of real world images. This dissertation also proposes a new randomization method for robust image hashing based on Higher Order Spectra (HOS) and Radon projections. The method is non-linear and this is an essential requirement for non-invertibility. The method is also designed to produce features more suited for quantization and encoding. The system can operate without the need for quantizer training, is more easily encoded and displays improved hashing performance when compared to existing robust image hashing algorithms. The dissertation also shows how the HOS method can be adapted to work with biometric features obtained from 2D and 3D face images.

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Sol-gel synthesis in varied gravity is only a relatively new topic in the literature and further investigation is required to explore its full potential as a method to synthesise novel materials. Although trialled for systems such as silica, the specific application of varied gravity synthesis to other sol-gel systems such as titanium has not previously been undertaken. Current literature methods for the synthesis of sol-gel material in reduced gravity could not be applied to titanium sol-gel processing, thus a new strategy had to be developed in this study. To successfully conduct experiments in varied gravity a refined titanium sol-gel chemical precursor had to be developed which allowed the single solution precursor to remain un-reactive at temperatures up to 50oC and only begin to react when exposed to a pressure decrease from a vacuum. Due to the new nature of this precursor, a thorough characterisation of the reaction precursors was subsequently undertaken with the use of techniques such as Nuclear Magnetic Resonance, Infra-red and UV-Vis spectroscopy in order to achieve sufficient understanding of precursor chemistry and kinetic stability. This understanding was then used to propose gelation reaction mechanisms under varied gravity conditions. Two unique reactor systems were designed and built with the specific purpose to allow the effects of varied gravity (high, normal, reduced) during synthesis of titanium sol-gels to be studied. The first system was a centrifuge capable of providing high gravity environments of up to 70 g’s for extended periods, whilst applying a 100 mbar vacuum and a temperature of 40-50oC to the reaction chambers. The second system to be used in the QUT Microgravity Drop Tower Facility was also required to provide the same thermal and vacuum conditions used in the centrifuge, but had to operate autonomously during free fall. Through the use of post synthesis characterisation techniques such as Raman Spectroscopy, X-Ray diffraction (XRD) and N2 adsorption, it was found that increased gravity levels during synthesis, had the greatest effect on the final products. Samples produced in reduced and normal gravity appeared to form amorphous gels containing very small particles with moderate surface areas. Whereas crystalline anatase (TiO2), was found to form in samples synthesised above 5 g with significant increases in crystallinity, particle size and surface area observed when samples were produced at gravity levels up to 70 g. It is proposed that for samples produced in higher gravity, an increased concentration gradient of water is forms at the bottom of the reacting film due to forced convection. The particles formed in higher gravity diffuse downward towards this excess of water, which favours the condensation reaction of remaining sol gel precursors with the particles promoting increased particle growth. Due to the removal of downward convection in reduced gravity, particle growth due to condensation reaction processes are physically hindered hydrolysis reactions favoured instead. Another significant finding from this work was that anatase could be produced at relatively low temperatures of 40-50oC instead of the conventional method of calcination above 450oC solely through sol-gel synthesis at higher gravity levels. It is hoped that the outcomes of this research will lead to an increased understanding of the effects of gravity on chemical synthesis of titanium sol-gel, potentially leading to the development of improved products suitable for diverse applications such as semiconductor or catalyst materials as well as significantly reducing production and energy costs through manufacturing these materials at significantly lower temperatures.

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Many who have taken a tax course in the last few years will be aware of the plight of Ms Symone Anstis. Her story is a simple one. The year is 2006 and Ms Anstis, an undergraduate student is undertaking a teaching degree at the Australian Catholic University. To support herself she works at Katies earning $14,946, and receives Youth Allowance of $3,622. In her tax return for that year Ms Anstis claims $920 for ‘self-education expenses’ comprising travel, supplies, student administration fees, depreciation on her computer, textbooks and stationery. These expenses totalling $1,170 are correctly reduced by the non-deductible first $250, per s 82A of the Income Tax Assessment Act (1997) (Cth) (ITAA97). Ms Anstis claims a deduction for ‘self-education expenses’ on the basis that a condition of receiving Youth Allowance is the enrolment and satisfactory progress in an acceptable course of study. Generally, a deduction is allowed where a loss or outgoing is incurred in gaining or producing assessable income and that loss or outgoing is not of a private or domestic nature. Ms Anstis claims the expenses are incurred to meet the requirements of maintaining Youth Allowance so the nexus is satisfied. On assessment, the Commissioner of Taxation disallows the deduction claimed on the basis that ‘self-education expenses’ are only deductible if they have a relevant connection to the taxpayer’s current income-earning activities or they are likely to lead to an increase in a taxpayer’s income from his or her current income-earning activities in the future.

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Objectives To examine the effect of extreme temperatures on emergency department admissions (EDAs) for childhood asthma. Methods An ecological design was used in this study. A Poisson linear regression model combined with a distributed lag non-linear model was used to quantify the effect of temperature on EDAs for asthma among children aged 0–14 years in Brisbane, Australia, during January 2003–December 2009, while controlling for air pollution, relative humidity, day of the week, season and long-term trends. The model residuals were checked to identify whether there was an added effect due to heat waves or cold spells. Results There were 13 324 EDAs for childhood asthma during the study period. Both hot and cold temperatures were associated with increases in EDAs for childhood asthma, and their effects both appeared to be acute. An added effect of heat waves on EDAs for childhood asthma was observed, but no added effect of cold spells was found. Male children and children aged 0–4 years were most vulnerable to heat effects, while children aged 10–14 years were most vulnerable to cold effects. Conclusions Both hot and cold temperatures seemed to affect EDAs for childhood asthma. As climate change continues, children aged 0–4 years are at particular risk for asthma.

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This study explores and evaluates students’ and teachers’ experiences when using a range of Web 2.0 tools in Higher Education teaching and learning. It contributes to our understanding of how Web 2.0 learning communities are constructed, experienced and the nature of the participation therein. This research extends our knowledge and understanding of the Web 2.0 phenomena, and provides a framework that can assist with improving future Web 2.0 implementation.

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Climate change is leading to an increased frequency and severity of heat waves. Spells of several consecutive days of unusually high temperatures have led to increased mortality rates for the more vulnerable in the community. The problem is compounded by the escalating energy costs and increasing peak electrical demand as people become more reliant on air conditioning. Domestic air conditioning is the primary determinant of peak power demand which has been a major driver of higher electricity costs. This report presents the findings of multidisciplinary research which develops a national framework to evaluate the potential impacts of heat waves. It presents a technical, social and economic approach to adapt Australian residential buildings to ameliorate the impact of heat waves in the community and reduce the risk of its adverse outcomes. Through the development of a methodology for estimating the impact of global warming on key weather parameters in 2030 and 2050, it is possible to re-evaluate the size and anticipated energy consumption of air conditioners in future years for various climate zones in Australia. Over the coming decades it is likely that mainland Australia will require more cooling than heating. While in some parts the total electricity usage for heating and cooling may remain unchanged, there is an overall significant increase in peak electricity demand, likely to further drive electricity prices. Through monitoring groups of households in South Australia, New South Wales and Queensland, the impact of heat waves on both thermal comfort sensation and energy consumption for air conditioning has been evaluated. The results show that households are likely to be able to tolerate slightly increased temperature levels indoors during periods of high outside temperatures. The research identified that household electricity costs are likely to rise above what is currently projected due to the impact of climate change. Through a number of regulatory changes to both household design and air conditioners, this impact can be minimised. A number of proposed retrofit and design measures are provided, which can readily reduce electricity usage for cooling at minimal cost to the household. Using a number of social research instruments, it is evident that households are willing to change behaviour rather than to spend money. Those on lower income and elderly individuals are the least able to afford the use of air conditioning and should be a priority for interventions and assistance. Increasing community awareness of cost effective strategies to manage comfort and health during heat waves is a high priority recommended action. Overall, the research showed that a combined approach including behaviour change, dwelling modification and improved air conditioner selection can readily adapt Australian households to the impact of heat waves, reducing the risk of heat related deaths and household energy costs.

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The techniques of environmental scanning electron microscopy (ESEM) and Raman microscopy have been used to respectively elucidate the morphological changes and nature of the adsorbed species on silver(I) oxide powder, during methanol oxidation conditions. Heating Ag2O in either water vapour or oxygen resulted firstly in the decomposition of silver(I) oxide to polycrystalline silver at 578 K followed by sintering of the particles at higher temperature. Raman spectroscopy revealed the presence of subsurface oxygen and hydroxyl species in addition to surface hydroxyl groups after interaction with water vapour. Similar species were identified following exposure to oxygen in an ambient atmosphere. This behaviour indicated that the polycrystalline silver formed from Ag2O decomposition was substantially more reactive than silver produced by electrochemical methods. The interaction of water at elevated temperatures subsequent to heating silver(I) oxide in oxygen resulted in a significantly enhanced concentration of subsurface hydroxyl species. The reaction of methanol with Ag2O at high temperatures was interesting in that an inhibition in silver grain growth was noted. Substantial structural modification of the silver(I) oxide material was induced by catalytic etching in a methanol/air mixture. In particular, "pin-hole" formation was observed to occur at temperatures in excess of 773 K, and it was also recorded that these "pin- holes" coalesced to form large-scale defects under typical industrial reaction conditions. Raman spectroscopy revealed that the working surface consisted mainly of subsurface oxygen and surface Ag=O species. The relative lack of sub-surface hydroxyl species suggested that it was the desorption of such moieties which was the cause of the "pin-hole" formation.

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Information literacy has been a significant issue in the library community for many years. It is now being recognised as an important issue by the higher education community. This theoretical framework draws together important elements of the information literacy agenda specifically for tertiary educators and administrators. The frame-work examines three areas of primary concern: the possible outcomes of information literacy education (through outlining the characteristics of information literate people); the nature of information literacy education; and the potential role of stake-holders (including information services, faculty, staff developers and learning counsellors) in helping staff and students to be information literate. This theoretical framework forms part of the Griffith University Information Literacy Blueprint. The Blueprint was designed between June and August of 1994. The project, a quality initiative of the Division of Information Services, was led by Janice Rickards, University Librarian.

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Australian higher education is presently subject to a period of substantial change. The needs of the economy and workforce, together with the broader educational role of the university are leading to focus on lifelong learning as a tool for bringing together the apparently diverging needs of different groups. Within this broader context, the emphasis on lifelong learning and associated graduate capabilities is leading to opportunities for new partnerships between faculty and librarians, partnerships that bring the two groups together in ways that are helping to transform the experience of teaching and learning. This paper explores emerging partnerships in diverse areas, including research and scholarship, curriculum, policy, supervision, and staff development. They are in the early phases of development and result from a broad focus on the learning and information literacy needs of students, as opposed to a narrow focus on using the library and its information resources. Taken together, and viewed from a system-wide perspective, these partnerships reveal a complex dynamic that is deserving of wider attention across the Australian higher education system and internationally.

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Background Many Australian cities experience large winter increases in deaths and hospitalisations. Flu outbreaks are only part of the problem and inadequate protection from cold weather is a key independent risk factor. Better home insulation has been shown to improve health during winter, but no study has examined whether better personal insulation improves health. Data and Methods We ran a randomised controlled trial of thermal clothing versus usual care. Subjects with heart failure (a group vulnerable to cold) were recruited from a public hospital in Brisbane in winter and followed-up at the end of winter. Those randomised to the intervention received two thermal hats and tops and a digital thermometer. The primary outcome was the number of days in hospital, with secondary outcomes of General Practitioner (GP) visits and self-rated health. Results The mean number of days in hospital per 100 winter days was 2.5 in the intervention group and 1.8 in the usual care group, with a mean difference of 0.7 (95% CI: –1.5, 5.4). The intervention group had 0.2 fewer GP visits on average (95% CI: –0.8, 0.3), and a higher self-rated health, mean improvement –0.3 (95% CI: –0.9, 0.3). The thermal tops were generally well used, but even in cold temperatures the hats were only worn by 30% of subjects. Conclusions Thermal clothes are a cheap and simple intervention, but further work needs to be done on increasing compliance and confirming the health and economic benefits of providing thermals to at-risk groups.