988 resultados para REFINEMENT


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Equi-channel angular pressing (ECAP) of a Pb–Sn eutectic alloy up to six passes in a T-shaped die, rather than a conventional L-shaped die, was studied for grain refinement. The effect of ECAP on the hardness and tensile properties was studied. Microstructure predominately changed in the early part of the ECAP process and became equiaxed and uniformly distributed in both the longitudinal and the transverse sections after four passes. There occurred substantial softening over the first two passes—hardness of 10 Hv, yield strength of 14.2 MPa and tensile strength of 16.3 MPa in the as-cast condition decreased upon two passes to 6 Hv, 9.7 MPa and 13.0 MPa, respectively. The ductility (% elongation) increased drastically from <50% in the as-cast condition to 150% upon two passes, and further increased to 230% after four passes. Various tensile properties and concurrent microstructural evolution were used to develop a mutual relationship among them.

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The problem of dimensional defects in aluminum die-castings is widespread throughout the foundry industry and their detection is of paramount importance in maintaining product quality. Due to the unpredictable factory environment and metallic with highly reflective nature, it is extremely hard to estimate true dimensionality of these metallic parts, autonomously. Some existing vision systems are capable of estimating depth to high accuracy, however are very much hardware dependent, involving the use of light and laser pattern projectors, integrated into vision systems or laser scanners. However, due to the reflective nature of these metallic parts and variable factory environments, the aforementioned vision systems tend to exhibit unpromising performance. Moreover, hardware dependency makes these systems cumbersome and costly. In this work, we propose a novel robust 3D reconstruction algorithm capable of reconstructing dimensionally accurate 3D depth models of the aluminum die-castings. The developed system is very simple and cost effective as it consists of only a pair of stereo cameras and a defused fluorescent light. The proposed vision system is capable of estimating surface depths within the accuracy of 0.5mm. In addition, the system is invariant to illuminative variations as well as orientation and location of the objects on the input image space, making the developed system highly robust. Due to its hardware simplicity and robustness, it can be implemented in different factory environments without a significant change in the setup. The proposed system is a major part of quality inspection system for the automotive manufacturing industry.

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In the current study, the role of dynamic strain induced transformation on ferrite grain refinement was investigated using different thermomechanical processing routes. A Ni-30Fe austenitic model alloy was also employed to study the evolution of the deformation structure under different deformation conditions. It was shown that the extreme refinement of ferrite is more likely due to the formation of extensive high angle intragranular defects in the austenite through deformation. Among the different thermomechanical parameters, the deformation temperature had a significant effect on the intragranular defect characteristics. There was a transition where the cell dislocation structure changed to laminar microband structures with a decrease in the deformation temperature. Moreover, the ultrafine grained structure was also successfully produced through static transformation using warm deformation process; in other words, concurrent deformation and transformation are not necessary for ultrafine ferrite formation.

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Agenda 21 may be considered the most significant programme of action influencing environmental policy for the Australian development and construction industry. The industry has remained one of the most rapidly expanding sectors; yet, we have seen the gradual process of exhausting natural resources and irreversible environmental degradation. Even with the introduction of numerous new environmental policies, it remains questionable as to whether real improvements have occurred across the industry. Legislative mechanisms to direct on-site environmental management appear deficient; information flows between participants along the supply chain appear to impact upon environmental management performance; and industry fragmentation remains compounded by ill-defined external, non-contractual supply chain influences that directly impact on contractual systems. Limited research has considered construction supply chain theory and environmental management particularly in reference to policy. The literature highlighted a need to develop a supply chain model which seeks to integrate chain actors and government regulators through holistic information management. The model assumes that fundamental to industry change is statutory control to mandate construction environmental management plans. However, industry change and subsequent environmental management rely upon effective information dissemination. The next stage involves model refinement, investigating barriers and enablers to widespread diffusion of such an innovative integrated environmental management system.

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Background : Intimate partner violence (IPV) is prevalent globally, experienced by a significant minority of women in the early childbearing years and is harmful to the mental and physical health of women and children. There are very few studies with rigorous designs which have tested the effectiveness of IPV interventions to improve the health and wellbeing of abused women. Evidence for the separate benefit to victims of social support, advocacy and non-professional mentoring suggested that a combined model may reduce the levels of violence, the associated mental health damage and may increase a woman's health, safety and connection with her children. This paper describes the development, design and implementation of a trial of mentor mother support set in primary care, including baseline characteristics of participating women.

Methods/Design : MOSAIC (MOtherS' Advocates In the Community) was a cluster randomised trial embedded in general practice and maternal and child health (MCH) nursing services in disadvantaged suburbs of Melbourne, Australia. Women who were pregnant or with infants, identified as abused or symptomatic of abuse, were referred by IPV-trained GPs and MCH nurses from 24 general practices and eight nurse teams from January 2006 to December 2007. Women in the intervention arm received up to 12 months support from trained and supported non-professional mentor mothers. Vietnamese health professionals also referred Vietnamese women to bilingual mentors in a sub-study. Baseline and follow-up surveys at 12 months measured IPV (CAS), depression (EPDS), general health (SF-36), social support (MOS-SF) and attachment to children (PSI-SF). Significant development and piloting occurred prior to trial commencement. Implementation interviews with MCH nurses, GPs and mentors assisted further refinement of the intervention. In-depth interviews with participants and mentors, and follow-up surveys of MCH nurses and GPs at trial conclusion will shed further light on MOSAIC's impact.

Discussion : Despite significant challenges, MOSAIC will make an important contribution to the need for evidence of effective partner violence interventions, the role of non-professional mentors in partner violence support services and the need for more evaluation of effective health professional training and support in caring for abused women and children among their populations.

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This paper discusses the development and preliminary analysis of psychology undergraduate courses on cultural competence in relation to Indigenous Australians. The paper summarises the process that led to the formation of draft curriculum guidelines for psychology academics, including the need to critically examine the assumptions and history of Western psychology in relation to Indigenous peoples, the inclusion of non-conventional teaching and learning methods, staff and institutional support, and appropriate staff development. The paper then discusses the responses of students to one of the courses developed from these guidelines. The courses were well received by students and although they do not in themselves teach professional psychological skills in working effectively with Indigenous people, they provide a solid basis for the development of such skills. Because this is a relatively new area, it is likely that there will be much refinement of these courses in coming years.

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School Innovation in Science is a major Victorian Government initiative that developed and validated a model whereby schools can improve their  science teaching and learning. The initiative was developed and rolled out to more than 400 schools over the period 2000-2004. A research team worked with 200+ primary and secondary schools over three years, supporting them in developing new initiatives in science, and monitoring the impact on school and classroom practice, and student outcomes. The research effort underpinning the development phase included the development and validation of a set of components describing effective teaching, the refinement of a school and teacher change strategy, the development of instruments to monitor teacher classroom practice and a variety of student outcomes, and the development of insights into the change process using questionnaires, observations, and interviews across four years. This paper describes the project and its major outcomes, and raises a number of issues concerning the nature of school and teacher change, pedagogy, school and community, and student learning, and the way these interact. A number of research issues are raised by the size and developmental nature of the project, the range of research methods, and the different audiences served by the research. The issue of sustainability of such system-wide change initiatives is discussed.

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This paper analyses various uses of narrative in the exploration of teacher identity. It highlights the way many contemporary education writers use terminology such as ‘storying lives’ and ‘storied landscapes’ to describe teacher processes of reflection on practice. In this paper the authors discuss some recent approaches to narrative that incorporate or suggest systematic uses of narrative theory (Conle 2003, Kamler, 2001, Richardson, 2003). Consideration is also given to the links between critical ethnography and narrative in order to critique the use of teacher portfolios, as in a recent Australian initiative for the appraisal of beginning teachers. The authors conclude with an argument for the rehabilitation and refinement of narrative theory in the ‘writing’ of teacher identity.

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In the present paper the effect of grain refinement on the dynamic response of ultra fine-grained (UFG) structures for C–Mn and HSLA steels is investigated. A physically based flow stress model (Khan-Huang-Liang, KHL) was used to predict the mechanical response of steel structures over a wide range of strain rates and grain sizes. However, the comparison was restricted to the bcc ferrite structures. In previous work [K. Muszka, P.D. Hodgson, J. Majta, A physical based modeling approach for the dynamic behavior of ultra fine-grained structures, J. Mater. Process. Technol. 177 (2006) 456–460] it was shown that the KHL model has better accuracy for structures with a higher level of refinement (below 1 μm) compared to other flow stress models (e.g. Zerrili-Armstrong model). In the present paper, simulation results using the KHL model were compared with experiments. To provide a wide range of the experimental data, a complex thermomechanical processing was applied. The mechanical behavior of the steels was examined utilizing quasi-static tension and dynamic compression tests. The application of the different deformation histories enabled to obtain complex microstructure evolution that was reflected in the level of ferrite refinement.

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The objective of this paper is to introduce and describe a conceptual framework of firms' corporate and business ethics in supply chains in terms of ethical structures, ethical processes and ethical performance. A framework is outlined and positioned incorporating an ethical frame of reference in the field of Supply Chain Management (SCM). A number of areas and sub-areas of firms' corporate and business ethics are framed in the context of supply chains. The introduced framework should be seen as a seed for further development and refinement in the field of SCM. It provides opportunities for further research of ethical concerns in supply chains.

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This thesis is based primarily on work published in academic refereed journals between 1994 and 2003. Taken as a whole, the thesis explores and enacts an evolving methodology for curriculum inquiry which foregrounds the generativity of fiction in reading, writing and representing curriculum problems and issues. This methodology is informed by the narrative and textual 'turns' in the humanities and social sciences - especially poststructuralist and deconstructive approaches to literary and cultural criticism - and is performed as a series of narrative experiments and 'intertextual turns'. Narrative theory suggests that we can think of all discourse as taking the form of a story, and poststructuralist theorising invites us to think of all discourse as taking the form of a text; this thesis argues that intertextual and deconstructive readings of the stories and texts that constitute curriculum work can produce new meanings and understandings. The thesis places particular emphasis on the uses of fiction and fictional modes of representation in curriculum inquiry and suggests that our purposes might sometimes be better served by (re)presenting the texts we produce as deliberate fictions rather than as 'factual' stories. The thesis also demonstrates that some modes and genres of fiction can help us to move our research efforts beyond 'reflection' (an optical metaphor for displacing an image) by producing texts that 'diffract' the normative storylines of curriculum inquiry (diffraction is an optical metaphor for transformation). The thesis begins with an introduction that situates (autobiographically and historically) the narrative experiments and intertextual turns performed in the thesis as both advancements in, and transgressions of, deliberative and critical reconceptualist curriculum theorising. Several of the chapters that follow examine textual continuities and discontinuities between the various objects and methods of curriculum inquiry and particular fictional genres (such as crime stories and science fiction) and/or particular fictional works (including Bram Stoker's Dracula, J.M. Coetzee's Disgrace, and Ursula Le Guin's The Telling). Other chapters demonstrate how intertextual and deconstructive reading strategies can inform inquiries focused on specific subject matters (with particular reference to environmental education) and illuminate contemporary issues and debates in curriculum (especially the internationalisation and globalisation of curriculum work). The thesis concludes with suggestions for further refinement of methodologies that privilege narrative and fiction in curriculum inquiry.

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A simple series of test was developed to highlight and compare the difference between the static strain induced transformation (SSIT) and the dynamic strain induced transformation (DSIT) mechanism in grain refinement and also to investigate the origin of the difference between the two mechanisms. The results showed that while the SSIT sets up a two-dimensional impingement among the ferrite grains, it cannot avoid their coarsening (normal growth). However, the DSIT forms a group of grains with a three-dimensional impingement which does not coarsen and maintains their fine size throughout the transformation, thereby, reduces the final average grain size.

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In this study, a novel experimental approach was applied to study the mechanism of the equiaxed shape retention in dynamic strain induced ferrite during deformation. The post-deformation ferrite evolution in both static and dynamic transformation was studied. The refinement potential and the origin of their differences in both mechanisms were analysed.

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A multi-resolution technique for matching a stereo pair of images based on translation invariant discrete multi-wavelet transform is presented. The technique uses the well known coarse to fine strategy, involving the calculation of matching points at the coarsest level with consequent refinement up to the finest level. Vector coefficients of the wavelet transform modulus are used as matching features, where modulus maxima defines the shift invariant high-level features (multiscale edges) with phase pointing to the normal of the feature surface. The technique addresses the estimation of optimal corresponding points and the corresponding 2D disparity maps. Illuminative variation that can exist between the perspective views of the same scene is controlled using scale normalization at each decomposition level by dividing the details space coefficients with approximation space and then using normalized correlation. The problem of ambiguity, explicitly, and occlusion, implicitly, is addressed by using a geometric topological refinement procedure and symbolic tagging.

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The thesis is a refinement of semiotic theory in architecture which aims towards developing a conversation between Western theory and the Eastern city. Using theoretical bases including semiotic theory, Japanese analytical text and analogies of cultural products, this thesis proposes that urban language can be perceived and analysed.