65 resultados para insulated gate bipolar transistor (IGBT)
Resumo:
Airports are a place of transition, empty halls of fleeting comings, goings and waitings. 'Gate 38' follows the experience of four groups of young people trapped at this point of departure. As contact with the outside world is cut off, the focus is placed squarely on what they’re doing, and where they’re going. A non-traditional musical set at the end of the world. Commissioned by MacGregor State High School's Centre of Artistic Development, script development included workshops with the CAD class of 2007. No musical score required.
Resumo:
As part of an ongoing research on the development of a longer life insulated rail joint (IRJ), this paper reports a field experiment and a simplified 2D numerical modelling for the purpose of investigating the behaviour of rail web in the vicinity of endpost in an insulated rail joint (IRJ) due to wheel passages. A simplified 2D plane stress finite element model is used to simulate the wheel-rail rolling contact impact at IRJ. This model is validated using data from a strain gauged IRJ that was installed in a heavy haul network; data in terms of the vertical and shear strains at specific positions of the IRJ during train passing were captured and compared with the results of the FE model. The comparison indicates a satisfactory agreement between the FE model and the field testing. Furthermore, it demonstrates that the experimental and numerical analyses reported in this paper provide a valuable datum for developing further insight into the behaviour of IRJ under wheel impacts.
Resumo:
A finite element numerical simulation is carried out to examine stress distributions on railhead in the cicinity of the endpost of an insulated rail joint. The contact patch and pressure distribution are considered using modified Hertzian simulation. A combined elasto-plastic material modelling available in Abaqus is employed in the simulation. A dynamic load factor of 1.21 is considered in modelling for the wheel load based on a previous study as part of this on going research. Shakedown theorem is employed in this study. A peak pressure load which is above the shakedown limit is determined as input load. As a result, a progressive damage in the railhead has been captured as depicted in the equivalent plastic strain plot.
Resumo:
Airports are a place of transition, empty halls of fleeting comings, goings and waitings. 'Gate 38' follows the experience of four groups of young people trapped at this point of departure. As contact with the outside world is cut off, the focus is placed squarely on what they’re doing, and where they’re going. A non-traditional musical set at the end of the world. Commissioned by MacGregor State High School's Centre of Artistic Development, script development included workshops with the CAD class of 2007. No musical score required.
Elasto-plastic stress analysis of an insulated rail joint (IRJ) with a loading below shakedown limit
Resumo:
A finite element numerical simulation is carried out to examine stress distributions on railhead in the vicinity of the endpost of a insulated rail joint. The contact patch and pressure distribution are considered using modified Hertzian formulation. A combined elasto-plastic material modelling available in Abaqus is employed in the simulation. A dynamic load factor of 1.21 is considered in modelling for the wheel load based on a previous study as part of this on going research. Shakedown theorem is employed in this study. A peak pressure load which is above the shakedown limit is determined as input load. As a result, a progressive damage in the railhead has been captured as depicted in the equivalent plastic strain plot.
Resumo:
Insulated rail joints (IRJs) possess lower bending stiffness across the gap containing insulating endpost and hence are subjected to wheel impact. IRJs are either square cut or inclined cut to the longitudinal axis of the rails in a vertical plane. It is generally claimed that the inclined cut IRJs outperformed the square cut IRJs; however, there is a paucity of literature with regard to the relative structural merits of these two designs. This article presents comparative studies of the structural response of these two IRJs to the passage of wheels based on continuously acquired field data from joints strain-gauged closer to the source of impact. Strain signatures are presented in time, frequency, and avelet domains and the peak vertical and shear strains are systematically employed to examine the relative structural merits of the two IRJs subjected to similar real-life loading. It is shown that the inclined IRJs resist the wheel load with higher peak shear strains and lower peak vertical strains than that of the square IRJs.
Resumo:
This PhD represents my attempt to make sense of my personal experiences of depression through the form of cabaret. I first experienced depression in 2006. Previously, I had considered myself to be a happy and optimistic person. I found the experience of depression to be a shock: both in the experience itself, and also in the way it effected my own self image. These personal experiences, together with my professional history as a songwriter and cabaret performer, have been the motivating force behind the research project. This study has explored the question: What are the implications of applying principles of Michael White’s narrative therapy to the creation of a cabaret performance about depression and bipolar disorder? There is a 50 percent weighting on the creative work, the cabaret performance Mind Games, and a 50 percent weighting on the written exegesis. This research has focussed on the illustration of therapeutic principles in order to play games of truth within a cabaret performance. The research project investigates ways of telling my own story in relation to others’ stories through three re-authoring principles articulated in Michael White’s narrative therapy: externalisation, an autonomous ethic of living and rich descriptions. The personal stories presented in the cabaret were drawn from my own experiences and from interviews with individuals with depression or bipolar disorder. The cabaret focussed on the illustration of therapeutic principles, and was not focussed on therapeutic ends for myself or the interviewees. The research question has been approached through a methodology combining autoethnographic, practice-led and action research. Auto ethnographic research is characterised by close investigation of assumptions, attitudes, and beliefs. The combination of autoethnographic, practice-led, action research has allowed me to bring together personal experiences of mental illness, research into therapeutic techniques, social attitudes and public discourses about mental illness and forms of contemporary cabaret to facilitate the creation of a one-woman cabaret performance. The exegesis begins with a discussion of games of truth as informed by Michel Foucault and Michael White and self-stigma as informed by Michael White and Erving Goffman. These concepts form the basis for a discussion of my own personal experiences. White’s narrative therapy is focused on individuals re-authoring their stories, or telling their stories in different ways. White’s principles are influenced by Foucault’s notions of truth and power. Foucault’s term games of truth has been used to describe the effect of a ‘truth in flux’ that occurs through White’s re-authoring process. This study argues that cabaret is an appropriate form to represent this therapeutic process because it favours heightened performativity over realism, and showcases its ‘constructedness’ and artificiality. Thus cabaret is well suited to playing games of truth. A contextual review compares two major cabaret trends, personal cabaret and provocative cabaret, in reference to the performer’s relationship with the audience in terms of distance and intimacy. The study draws a parallel between principles of distance and intimacy in Michael White’s narrative therapy and relates these to performative terms of distance and intimacy. The creative component of this study, the cabaret Mind Games, used principles of narrative therapy to present the character ‘Jo’ playing games of truth through: externalising an aspect of her personality (externalisation); exploring different life values (an autonomous ethic of living); and enacting multiple versions of her identity (rich descriptions). This constant shifting between distance and intimacy within the cabaret created the effect of a truth in ‘constant flux’, to use one of White’s terms. There are three inter-related findings in the study. The first finding is that the application of principles of White’s narrative therapy was able to successfully combine provocative and empathetic elements within the cabaret. The second finding is that the personal agenda of addressing my own self-stigma within the project limited the effective portrayal of a ‘truth in flux’ within the cabaret. The third finding presents the view that the cabaret expressed ‘Jo’ playing games of truth in order to journey towards her own "preferred identity claim" (White 2004b) through an act of "self care" (Foucault 2005). The contribution to knowledge of this research project is the application of therapeutic principles to the creation of a cabaret performance. This process has focussed on creating a self-revelatory cabaret that questions notions of a ‘fixed truth’ through combining elements of existing cabaret forms in new ways. Two major forms in contemporary cabaret, the personal cabaret and the provocative cabaret use the performer-audience relationship in distinctive ways. Through combining elements of these two cabaret forms, I have explored ways to create a provocative cabaret focussed on the act of self-revelation.
Resumo:
The purpose of this project was to conduct an empirical study that would result in findings that inform systemic policy development aimed at improving tertiary participation and attainment by students from low socioeconomic status (LSES) backgrounds in Queensland. The project focuses on systemic policy, initiatives and programs that encourage tertiary education participation and attainment by individuals from LSES backgrounds, rather than on institution-specific initiatives or programs. While the broad remit was to consider tertiary education participation, the study particularly highlights issues pertaining to LSES student participation and attainment in the higher education sector, given the notable under representation of this demographic subgroup in Australian universities. This study supports the strategic priority of addressing professional skills shortages and innovations aiming to improve human and social capital in the state of Queensland. The ultimate goal is to contribute to the enhancement of Queensland’s education and training system by maximising participation and attainment by people from LSES backgrounds in higher education, thereby improving their quality of life and future life choices and opportunities. The study addressed the following five research questions: 1. What are the major factors that promote or inhibit participation and attainment in tertiary education by LSES students in Queensland? 2. To what extent do systemic policies or practices(systemic factors) of Queensland’s tertiary education system promote or inhibit participation and attainment by LSES students? That is, what features of Queensland’s tertiary education system have a significant effect on participation and attainment by LSES students? 3. What system policies or practices are found to boost participation and attainment by LSES students in other jurisdictions? 4. What evidence is there to suggest that policies or practices that have boosted participation and attainment by LSES students in other jurisdictions would be successful if implemented in Queensland? 5. What are the implications of the research findings for Queensland’s tertiary education system to improve participation and attainment by LSES students? The project adopted a mixed methods approach to data collection. A comprehensive review of the literature was conducted to identify relevant state, national and international literature. Both qualitative and quantitative methodologies were used to collect data from a range of key stakeholders.
Resumo:
This paper presents the results of a recent investigation into Insulated Rail Joint Tie Plate fatigue failures. In particular it focuses on the results of data obtained through field strain gauge and accelerometer measurements of in-service Insulated Rail Joint Tie Plates. These measurements have identified a significant variability in the strains present in similar joints operating under identical load conditions. This variability in stress invariably has a significant influence on the life of the joints. The results of rainflow counting and a fatigue analysis are also presented.
Resumo:
Ratchetting failure of railhead material adjacent to endpost which is placed in the air gap between the two rail ends at insulated rail joints causes significant economic problems to the railway operators who rely on the proper functioning of these joints for train control using the signalling track circuitry. The ratchetting failure is a localised problem and is very difficult to predict even when complex analytical methods are employed. This paper presents a novel experimental technique that enables measurement of the progressive ratchetting. A special purpose test rig was developed for this purpose and commissioned by the Centre for Railway Engineering at Central Queensland University. The rig also provides the capability of testing of the wheel/rail rolling contract conditions. The results provide confidence that accurate measurement of the localised failure of railhead material can be achieved using the test rig.
Resumo:
When wheels pass over insulated rail joints (IRJs) a vertical impact force is generated. The ability to measure the impact force is valuable as the force signature helps understand the behaviour of the IRJs, in particular their potential for failure. The impact forces are thought to be one of the main factors that cause damage to the IRJ and track components. Study of the deterioration mechanism helps finding new methods to improve the service life of IRJs in track. In this research, the strain-gage-based wheel load detector, for the first time, is employed to measure the wheel–rail contact-impact force at an IRJ in a heavy haul rail line. In this technique, the strain gages are installed within the IRJ assembly without disturbing the structural integrity of IRJ and arranged in a full wheatstone bridge to form a wheel load detector. The instrumented IRJ is first tested and calibrated in the lab and then installed in the field. For comparison purposes, a reference rail section is also instrumented with the same strain gage pattern as the IRJ. In this paper the measurement technique, the process of instrumentation, and tests as well as some typical data obtained from the field and the inferences are presented.
Resumo:
Many computationally intensive scientific applications involve repetitive floating point operations other than addition and multiplication which may present a significant performance bottleneck due to the relatively large latency or low throughput involved in executing such arithmetic primitives on commod- ity processors. A promising alternative is to execute such primitives on Field Programmable Gate Array (FPGA) hardware acting as an application-specific custom co-processor in a high performance reconfig- urable computing platform. The use of FPGAs can provide advantages such as fine-grain parallelism but issues relating to code development in a hardware description language and efficient data transfer to and from the FPGA chip can present significant application development challenges. In this paper, we discuss our practical experiences in developing a selection of floating point hardware designs to be implemented using FPGAs. Our designs include some basic mathemati cal library functions which can be implemented for user defined precisions suitable for novel applications requiring non-standard floating point represen- tation. We discuss the details of our designs along with results from performance and accuracy analysis tests.