6,308 research outputs found

    A unified approach to computer analysis and modeling of spacecraft environmental interactions

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    A new, coordinated, unified approach to the development of spacecraft plasma interaction models is proposed. The objective is to eliminate the unnecessary duplicative work in order to allow researchers to concentrate on the scientific aspects. By streamlining the developmental process, the interchange between theories and experimentalists is enhanced, and the transfer of technology to the spacecraft engineering community is faster. This approach is called the UNIfied Spacecraft Interaction Model (UNISIM). UNISIM is a coordinated system of software, hardware, and specifications. It is a tool for modeling and analyzing spacecraft interactions. It will be used to design experiments, to interpret results of experiments, and to aid in future spacecraft design. It breaks a Spacecraft Ineraction analysis into several modules. Each module will perform an analysis for some physical process, using phenomenology and algorithms which are well documented and have been subject to review. This system and its characteristics are discussed

    Investigation of additives for improvement of adhesive and elastomer performance Final report

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    Improvement additives for adhesive and elastomer performanc

    Food Security: an ODA View

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    Summary The usefulness of food security as a specific donor objective must be kept in perspective. Food security issues are best dealt with us a subset of poverty issues more generally; in the longer term, economic growth is the solution to both poverty and hunger. ODA's country programme planning procedure is flexible enough to incorporate food Security approaches where these are a practical and cost?effective way of designing, targeting and monitoring poverty alleviation efforts

    Ring-fencing a budget for cancer drugs: is it fair?

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    Ring-fencing is defined as protecting funds for use in a specific area. In the NationalHealth Service in the UK, various methods to ring-fence cancer have beenemployed over the years; more recently the Cancer Drugs Fund in England hasenabled cancer drugs that would not normally be considered cost-effective to beprovided to patients. This has created variation in provision between England andthe devolved countries. While some would argue that ring-fencing allows majoradvances to be made in the treatment of a particular condition, others wouldargue that it is intrinsically unfair. In this debate, Graham and Cassidy have writtenan article arguing the affirmative position and Hughes and Duerden were invitedto respond directly to their arguments. As with all the RCPE's 'Currentcontroversies', the authors have been asked to take a deliberately polarisedposition and so the views they express may be somewhat overstated

    Analysis of the charging of the SCATHA (P78-2) satellite

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    The charging of a large object in polar Earth orbit was investigated in order to obtain a preliminary indication of the response of the shuttle orbiter to such an environment. Two NASCAP (NASA Charging Analyzer Program) models of SCATHA (Satellite Charging at High Altitudes) were used in simulations of charging events. The properties of the satellite's constituent materials were compiled and representations of the experimentally observed plasma spectra were constructed. Actual charging events, as well as those using test environments, were simulated. Numerical models for the simulation of particle emitters and detectors were used to analyze the operation of these devices onboard SCATHA. The effect of highly charged surface regions on the charging conductivity within a photosheath was used to interpret results from the onboard electric field experiment. Shadowing calculations were carried out for the satellite and a table of effective illuminated areas was compiled

    Stories as personal coaching philosophy

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    The importance of coaches developing and articulating a personal coaching philosophy which encapsulates their values and beliefs is widely recognised. Yet it is also acknowledged that many coaches resist what appears an abstract task or find it to be of limited use in their day-to-day practice. In this paper we explore the potential of an alternative approach to developing and articulating a personal coaching philosophy: storytelling. Following a discussion of the potential of stories, we present a story written by one coach which expresses her personal philosophy in a way that is firmly rooted in her coaching practice. Storytelling approaches, we suggest, can reveal the connections between abstract/general philosophy and the personal embodied experience of coaching. We reflect on the possibilities and problems of using stories as philosophy and offer some suggestions for how coaches may be supported in developing their coaching philosophy through storytelling

    Models for Chronology Selection

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    In this paper, we derive an expression for the grand canonical partition function for a fluid of hot, rotating massless scalar field particles in the Einstein universe. We consider the number of states with a given energy as one increases the angular momentum so that the fluid rotates with an increasing angular velocity. We find that at the critical value when the velocity of the particles furthest from the origin reaches the speed of light, the number of states tends to zero. We illustrate how one can also interpret this partition function as the effective action for a boosted scalar field configuration in the product of three dimensional de Sitter space and S1S^1. In this case, we consider the number of states with a fixed linear momentum around the S1S^1 as the particles are given more and more boost momentum. At the critical point when the spacetime is about to develop closed timelike curves, the number of states again tends to zero. Thus it seems that quantum mechanics naturally enforces the chronology protection conjecture by superselecting the causality violating field configurations from the quantum mechanical phase space.Comment: 20 pages, Late

    Making mentoring work: The need for rewiring epistemology

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    To help produce expert coaches at both participation and performance levels, a number of governing bodies have established coach mentoring systems. In light of the limited literature on coach mentoring, as well as the risks of superficial treatment by coach education systems, this paper therefore critically discusses the role of the mentor in coach development, the nature of the mentor-mentee relationship and, most specifically, how expertise in the mentee may best be developed. If mentors are to be effective in developing expert coaches then we consequently argue that a focus on personal epistemology is required. On this basis, we present a framework that conceptualizes mentee development on this level through a step by step progression, rather than unrealistic and unachievable leap toward expertise. Finally, we consider the resulting implications for practice and research with respect to one-on-one mentoring, communities of practice, and formal coach education

    Additional application of the NASCAP code. Volume 1: NASCAP extension

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    The NASCAP computer program comprehensively analyzes problems of spacecraft charging. Using a fully three dimensional approach, it can accurately predict spacecraft potentials under a variety of conditions. Several changes were made to NASCAP, and a new code, NASCAP/LEO, was developed. In addition, detailed studies of several spacecraft-environmental interactions and of the SCATHA spacecraft were performed. The NASCAP/LEO program handles situations of relatively short Debye length encountered by large space structures or by any satellite in low earth orbit (LEO)
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