4,139 research outputs found

    Experimental validation of a landing-dynamics computer program for legged spacecraft landers

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    Validation of a landing-dynamics computer program has been accomplished by comparing analytical data with data from a limited experimental program. Agreement obtained established the subject landing-dynamics computer program as a reliable design tool for legged spacecraft landers

    Technology requirements for an orbiting fuel depot: A necessary element of a space infrastructure

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    Advanced planning within NASA has identified several bold space exploration initiatives. The successful implementation of these missions will require a supporting space infrastructure which would include a fuel depot, an orbiting facility to store, transfer and process large quantities of cryogenic fluids. In order to adequately plan the technology development programs required to enable the construction and operation of a fuel depot, a multidisciplinary workshop was convened to assess critical technologies and their state of maturity. Since technology requirements depend strongly on the depot design assumptions, several depot concepts are presented with their effect on criticality ratings. Over 70 depot-related technology areas are addressed

    The properties of current limited spark chambers

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    An investigation has been made of the characteristics of the current limited spark chamber, in which it was found that certain anomalies existed in its operation. Such discrepancies are not found in the operation of the more conventional types of chamber. They are thought to be due to charge deposited on the dielectric walls producing internal electric fields across the gas which reduce the chamber efficiency. The variation of the clearing field has been investigated in regions far from the discharge, and would appear to be present throughout the chamber. Measurement of the decay constant of the charge agreed well with the value calculated considering the chamber capacity and surface resistivity of the glass, although on application of this constant, to determine equilibrium values of the clearing fields, a second, much longer decay process seemed to be suggested. A theoretical model for handling such small clearing fields has been examined, and applied to the system, thus giving an indication of the electron drift velocity and density of charge deposited on the walls The development of an approximate semiquantitative model of spark breakdown shows how different pulse delays will affect the growth of streamers, and describes qualitatively certain characteristics of the discharges noted during chamber operation. However, the lack of more detailed knowledge of certain discharge parameters does not allow a more detailed comparison

    Fabrication of large tungsten structures by chemical vapor deposition

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    Process is accomplished by reducing tungsten hexafluoride with hydrogen. Metallic tungsten of essentially 100 percent purity and density is produced and built up as dense deposit on heated mandrel assembly. Process variations are building up, sealing or bonding refractory metals at temperatures below transition temperatures of base metal substrates

    Weight outcomes audit for 34,271 adults referred to a primary care/commercial weight management partnership scheme

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    Copyright © 2011 S. Karger AG, Basel.Peer reviewedPublisher PD

    Experimental studies of perceptual processes, section four Progress report, Jan. 1 - Nov. 30, 1965

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    Effects of neurochemical drug on behavior and ribonucleic acid measurement

    Perceived thickness and creaminess modulates the short-term satiating effects of high protein drinks

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    Previous research suggests that increasing beverage protein content enhances subsequent satiety, but whether this effect is entirely attributable to post-ingestive effects of protein or is partly caused by the distinct sensory characteristics imparted by the presence of protein remains unclear. To try and discriminate nutritive from sensory effects of added protein, we contrasted effects of three higher energy (c. 1.2MJ) and one lower energy (LE: 0.35MJ) drink preloads on subsequent appetite and lunch intake. Two higher energy drinks had 44% of energy from protein, one with the sensory characteristics of a juice drink (HP-) and the second thicker and more creamy (HP+). The high-carbohydrate preload (HC+) was matched for thickness and creaminess to the HP+ drink. Participants (healthy male volunteers, n=26) consumed significantly less at lunch after the HP+ (566g) and HC+ (572g) than after HP- (623g) and LE (668g) drinks, although the compensation for drink energy accounted for only 50% of extra energy at best. Appetite ratings indicated that participants felt significantly less hungry and more full immediately before lunch in HP+ and HC+ compared to LE, with HP- intermediate. The finding that protein generated stronger satiety in the context of a thicker creamier drink (HP+ but not HP-), and that an isoenergetic carbohydrate drink (HC+) matched in thickness and creaminess to the HP+ drink generated the same pattern of satiety as HP+ both suggest an important role for these sensory cues in the development of protein-based satiety

    Choosing treatment for localised prostate cancer: A patient-conducted-interview study

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    Objectives: Treatment choice can be particularly difficult in localised prostate cancer because of the uncertainty involved. Indeed, some men prefer maintaining their masculine identity and quality of life to potentially securing longer-term survival through surgery or radiotherapy. UK health services are now obliged to leave the choice of treatment to the patient and the aim of this study is to improve understanding of patients’ experiences of choosing treatment. Methods: A one-day participative workshop where men of six months post-diagnosis design and conduct audio and video interviews on each other about their experiences of choosing treatment. Results: The findings show that treatment choice is a complex process combining emotional and rational elements. Information gathering and delegation to professional expertise were two key themes that emerged. Conclusions: The findings emphasise that treatment choice for localised prostate cancer is little like the traditional notions of consumerism from which it is derived. Importantly, the results illustrate, from a patient perspective, how health professionals can engage in their roles as information providers and as experts

    Seismic Design Basis — The UK Regulatory Position for New Nuclear Reactors

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    The purpose of this paper is to outline the seismic regulatory requirements relating to the site licensing of new nuclear power installations in the UK, and to describe the background and justification of the seismic design basis level for such installations. It outlines the potential seismic related hazards which should be covered, the factors which are considered important in establishing the level of hazard under consideration, and the techniques which could be used for hazard evaluation. In addition, the paper covers the level of uncertainty associated with the methodology and analytical techniques used in evaluating the seismic hazards
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