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Creep in fibre-reinforced polymer mat composites
Tensile creeps have been conducted upon a woven, glass-fibre laminated epoxy composite and a 0/90° cross ply, carbon fibre reinforced epoxy composite. For the laminate loading was aligned with a fibre direction. For the ply the loading was inclined to the fibres (off-axis).
Testing to stress levels up to 200 MPa and temperatures in the range 20°- 200°C has revealed a form of creep in each material. The creep observed is essentially primary in nature but with extended time âą1000 h, it may exhaust or resemble a pseudo-secondary regime with a low rate. Where the load carrying capacity is lost, through fibre breakage or tab slip, the creep rate accelerates suddenly to infinity in a few hours. Smooth creep curves apply to successful tests but many irregular curves resulted from grip failure. A phenomenological approach was used to model smooth curves using a summation of instantaneous, primary and secondary strain terms. For the mat reinforcement a consistent trend was not found between the secondary creep rate and a stress that was raised incrementally upon the same testpiece. However the cumulative instantaneous strain provided the correct elastic modulus. Creep in the solid laminate was believed to be due to a fibre straightening that yielded a limiting strain in a time beyond which the process exhausts.
Creep in cfrc was only evident when the fibres were inclined to the stress axis, indicating a viscous flow in the matrix. Moreover, it is believed that a viscous shear sliding between laminates or plies is more likely to contribute to an off-axis deformation mode which is not strain limited.http://www.brunel.ac.uk/about/acad/sed/sedstaff/design/DavidRee
Issues in the development of advance directives in mental health care
<i>Background</i>: Interest in advance directives in mental health care is growing internationally. There is no clear universal agreement as to what such an advance directive is or how it should function. <i>Aim</i>: To describe the range of issues embodied in the development of advance directives in mental health care. <i>Method</i>: The literature on advance directives is examined to highlight the pros and cons of different versions of advance directive. <i>Results</i>: Themes emerged around issues of terminology, competency and consent, the legal status of advance directives independent or collaborative directives and their content. Opinions vary between a unilateral legally enforceable instrument to a care plan agreed between patient and clinician. <i>Conclusion</i>: There is immediate appeal in a liberal democracy that values individual freedom and autonomy in giving weight to advance directives in mental health care. They do not, however, solve all the problems of enforced treatment and early access to treatment. They also raise new issues and highlight persistent problems. <i>Declaration</i> <i>of</i> <i>interest</i>: The research was funded by the Nuffield Foundation grant number
MNH/00015G
Creating a Consistent Poverty Measure Over Time Using NAS Procedures: 1996-2005
This paper presents an experimental poverty measure and compares it to the current official measure, now more than 40 years old. The experimental measure is based on an approach, drawn from work by a National Academy of Sciences (NAS) expert Panel, to consistently define basic needs and family resources. The experimental thresholds are based on out-of-pocket spending by families on basic goods and services and are based on an âoutflowsâ concept. The resource measure is based on an âinflowsâ concept and reflects money coming into the household that is available to meet oneâs basic needs. The U.S. Consumer Expenditure Survey serves as the basis for the experimental thresholds and the Current Population Survey Annual Social and Economic Supplement serves as the basis for the resource measure. Results for 1996 to 2005 are reported with trends examined. An important finding is that increases in expenditures for shelter and utilities, captured in the new thresholds, suggest a greater increase in the number of families not able to meet basic needs than is reflected by the official poverty statistics.NAS, Poverty, Consumer Exenditure Survey, Current Population Survey
Fragmentation of positronium in collision with He atoms
The absolute cross section for the fragmentation of positronium in collision with He atoms has been measured. The results are compared with available theories. The longitudinal energy distributions of positrons resulting from fragmentation have also been determined and are found to display a peak situated just below half the residual energy. This is suggestive of the occurrence of "electron loss to the continuum" in which the two residual charged particles lie in a low relative-velocity Coulomb-continuum state
Applying an Ecobiodevelopmental Framework to Food Insecurity: More Than Simply Food for Thought
Dramatic advances in developmental sciences are beginning to reveal the biological mechanisms underlying well-established associations between early childhood adversity and lifelong measures of limited productivity and poor health. The case studies by Chilton and Rabinowich provide poignant and compelling qualitative data that support an ecobiodevelopmental approach towards understanding and addressing both the complex causes and intergenerational consequences of food insecurity
Summary report of the Committee on Goals and Objectives
The Committee, appointed by President Roberts, had its first meeting in Atlanta for 2 1/2 hours on Saturday morning, August 21. The following members were present: Richard Homburger, Konrad Kubin, Murray Wells, Gary John Previts, Hanns-Martin Schoenfeld, Robert Raymond, Williard Stone, Charles Lamden and Hugh Hughes
Reflections on the uses of accounting history
Garner reflects on the value of accounting history upon the occasion of the establishment of the Academy of Accounting Historians
Reflections on international research in accounting: Vintage 1950
The principal purpose of this brief item is to furnish 1980 accounting researchers, now in generous number throughout the world, with a modest perspective on how far accounting research has come in slightly less than 30 years, based on the compilation of Professor Bray in his little booklet of 1952 and 1953. Evidently he had thought about the preparation of the Register for some years. He obviously also had to have a rather wide ranging correspondence and knowledge of accounting research in many countries, in order to undertake the writing of the manuscript for his printed work. As contrasted with the scores of accounting publications today, the numerous committees and boards undertaking accounting research, and the approximately ten thousand accounting professors of the world (many of whom are engaged in a multiplicity of accounting research topics), Professor Bray could accurately state in his Foreword that accounting is very largely an applied subject, and its development on research lines is a comparatively new and difficult undertaking. As a consequence, would-be entrants into this field are often at a loss to know where to start. The intention of this Register is to familiarize new research workers with what is already going on, and to help those already committed to keep in touch with changing ideas
A Comparative Analysis of Data Collection Systems Used in Radiography Educational Programs and the Role Mobile Electronic Devices Play
Each radiography program has a system to collect important data from didactic and clinical settings in order to accurately assess the progress and success of students, provide the needed student intervention, and provide accreditation agencies with appropriate documentation that demonstrates student success in reaching program learning outcomes. The purpose of this research study was to determine the method of data collection and documentation used by radiography programs to evaluate student progress and to examine if MEDs play a role in evaluating and documenting student skills at the point of care.
The majority of radiography programs in this study were using paper methods for data collection and program directors reported value in using MEDs in clinical education but revealed that barriers still exist and will need to be addressed in order to increase their usage in clinical education
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