1,000 research outputs found

    Marshall system for aerospace system simulation (MARSYAS), user's manual

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    The capabilities of the Marshall system for aerospace system simulation (MARSYAS) and how to use it are described. MARSYAS is a software system that allows easy setup and control of the simulation of the dynamics of large physical systems on a digital computer. The physical systems are modeled in the form of block diagrams or equations. The blocks can have multiple inputs and multiple outputs, and they can be nested to form hierarchies. The block diagrams can contain transfer functions, nonlinear and logical functions, equations, analog computer elements and FORTRAN programs. The input format of the equations can be combinations of nonlinear, time-varying differential equations and algebraic equations in their original format. MARSYAS could also serve as a storage and retrieval system for models as a basis for a model configuration control system on a central time-shared computer. The outputs of the simulation system can be not only time-responses but also other analysis data such as frequency response, power spectrum and stability parameters. The MARSYAS translator is written in FORTRAN running on the Univac 1108 computer under the EXEC 8 operating system

    Marshall system for aerospace simulation (MARSYAS)

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    System is simple flexible language which can be coded by users unfamiliar with computer programming. It is designed for engineers with little experience in simulation, who desire to simulate large physical systems. User has ability to mix differential equations with diagrams in his model. With few exceptions, there is no rigid statement-operator structure within given module

    Leveling coatings for reducing the atomic oxygen defect density in protected graphite fiber epoxy composites

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    Pinholes or other defect sites in a protective oxide coating provide pathways for atomic oxygen in low Earth orbit to reach underlying material. One concept of enhancing the lifetime of materials in low Earth orbit is to apply a leveling coating to the material prior to applying any reflective and protective coatings. Using a surface tension leveling coating concept, a low viscosity epoxy was applied to the surface of several composite coupons. A protective layer of 1000 A of SiO2 was deposited on top of the leveling coating, and the coupons were exposed to an atomic oxygen environment in a plasma asher. Pinhole populations per unit area were estimated by counting the number of undercut sites observed by scanning electron microscopy. Defect density values of 180,000 defects/sq cm were reduced to about 1000 defects/sq cm as a result of the applied leveling coating. These improvements occur at a mass penalty of about 2.5 mg/sq cm

    Using Photovoice in PETE Programs to Initiate Positive Change

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    The purpose of this presentation will be to provide teacher educators with an overview of the Photovoice methodology and its potential utility in curricular change. The National Association for Sport and Physical Education’s ([NASPE], 2008) PETE standards state educators should allow diversity to drive instructional related decision-making. Photovoice, a participatory action research methodology, is a tool teacher educators can use to be responsive to the continuously changing contexts of public schools

    Public Purpose Recreation Marketing: A Focus on the Relationships Between the Public and Public Lands

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    Marketing has long had a place in the planning and management of public sector recreation. In particular, the use of market segmentation has allowed leisure providers to better understand their clients’ needs and to tailor their services to the diversity of those needs. However, the use of marketing approaches is not without controversy and is sometimes perceived to be at odds with the public service or stewardship mandates often associated with recreation management. We suggest that wholesale adoption of basic marketing principles (such as the notion of giving people exactly what they want at a great price) may be inappropriate. An alternative form, relational marketing, may be better suited to public purpose organizations. Relational marketing focuses on the development or fostering of a relationship between the public and the public agency. Thus, relational marketing focuses on building confidence in the agency’s ability to guard the short- and long-term interests of the public. For example, for land management agencies, these objectives are embedded in legislative and policy mandates to provide outstanding opportunities for recreation, while at the same time protecting and enhancing the environment. Relational marketing seems better suited to these objectives compared with transactional marketing, which is more dominant in private sector businesses. Whereas transactional marketing focuses on fostering current and continuing purchases of goods and services, relational marketing extends beyond the direct economic exchange. In the public recreation settings, the public is considered more than a current or potential customer, they are also considered an owner or shareholder of the agency. Thus, repeat purchases or customer satisfaction are not sufficient measures of success for organizations with a public service mandate. Instead, relational marketing considers the perceptions that the many different groups of the public (e.g. participants and non-participants, supporters and non-supporters) have of the agency and its actions. The research reported here conceptualizes the relationship between the public and the agency into three dimensions: social trust (the degree to which individuals perceive the agency to share their views, goals, and values); commitment (the investment, attachment, and longevity of the relationship to the agency); and social responsibility (which includes attitudes towards the goals or public purposes of the agency). A market segmentation based on these dimensions yielded distinct subpopulations of the general public. The challenge for public agencies, such as the Forest Service, is to be responsive to the different relationships the public has with the agency. Collaborative planning efforts must acknowledge and incorporate knowledge of these differences in social trust, commitment, and social responsibility. Any public action or policy change should consider how it potentially affects the varying public’s relationship with the agency and the services it provides. Managers must demonstrate stewardship, care, responsiveness, and continuing service to today’s public and future generations. Any interaction with the public (e.g., marketing) should focus on the intended public purpose which guides the agency

    Performance and Carcass Characteristics of Feedlot Steers: Effects of Delayed Implanting and Programmed Feeding During the Growing Period

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    This experiment was conducted to determine the effect of programming the rate of gain and delaying the first implant in feedlot steers on feedlot performance and carcass characteristics. Ninety-six growing steers (269 ± 16.2 kg) were assigned to 12 pens in a completely randomized design. Treatments were implant (Synovex-SÂź; 20 mg estradiol benzoate and 200 mg progesterone; Fort Dodge Animal Health, Overland Park, KS) on d 1 or no implant and programmed feeding to gain at a slow (0.68 kg/d) or fast (1.14 kg/d) rate during the growing period; these treatments were randomly assigned (n = 8) to pens of steers in a 2 × 2 factorial arrangement. Steers were fed a growing diet and after 88 and 60 d (for steers fed to gain at a slow or fast rate, respectively), steers were transitioned to ad libitum consumption of a high concentrate finishing diet. Growing period implant treatments did not affect ADG but did affect (P\u3c0.01) gain efficiency during the finishing period. Feeding steers for a slow rate of BW gain during the growing period improved (P=0.062) gain efficiency in the finishing period (169 vs 145 g gain/kg feed). Correlation coefficients between fat thickness and marbling score obtained via ultrasound and fat thickness and marbling score measured at harvest were greater the closer the ultrasound measurements were made to the final harvest date. These data indicate that feeding level prior to the start of the finishing period may affect BW gain efficiency during the finishing period

    Does Migration Make You Happy?:A Longitudinal Study of Internal Migration and Subjective Well-Being

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    The authors acknowledge financial support from the Economic and Social Research Council (ESRC) (RES-625-28-0001). This project is part of the ESRC Centre for Population Change (CPC). Financial support from the Marie Curie programme under the European Union's Seventh Framework Programme (FP/2007-2013) / Career Integration Grant n. PCIG10-GA-2011-303728 (CIG Grant NBHCHOICE, Neighbourhood choice, neighbourhood sorting, and neighbourhood effects).The majority of quantitative studies on the consequences of internal migration focus almost exclusively on the labour-market outcomes and the material well-being of migrants. We investigate whether individuals who migrate within the UK become happier after the move than they were before, and whether the effect is permanent or transient. Using life-satisfaction responses from twelve waves of the British Household Panel Survey and employing a fixed-effects model, we derive a temporal pattern of migrants’ subjective well-being around the time of the migration event. Our findings make an original contribution by revealing that, on average, migration is preceded by a period when individuals experience a significant decline in happiness for a variety of reasons, including changes in personal living arrangements. Migration itself causes a boost in happiness, and brings people back to their initial levels. The research contributes, therefore, to advancing an understanding of migration in relation to set-point theory. Perhaps surprisingly, long-distance migrants are at least as happy as short-distance migrants despite the higher social and psychological costs involved. The findings of this paper add to the pressure to retheorize migration within a conceptual framework that accounts for social well-being from a life-course perspective.PostprintPeer reviewe

    Energy Security of China, India, the E.U. and the U.S. under Long-term Scenarios: Results from Six IAMs

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    This paper assesses energy security in three long-term energy scenarios (a business as usual development, a projection of Copenhagen commitments, and a 450 ppm stabilization scenario) as modeled in six integrated assessment models: GCAM, IMAGE, MESSAGE, ReMIND, TIAM-ECN and WITCH. We systematically evaluate potential long-term vulnerabilities of vital energy systems of four major economies: China, the European Union, India and the U.S., as expressed by several characteristics of energy trade, resource extraction, and diversity of energy options. Our results show that climate policies are likely to lead to significantly lower global energy trade and reduce energy imports of major economies, decrease the rate of resource depletion, and increase the diversity of energy options, particularly in the especially vulnerable transportation sector. China, India and the E.U. will derive particularly strong benefits from climate policies, whereas the U.S. may forego some opportunities to export fossil fuels in the second half of the century

    Assessing the challenges of global long-term mitigation scenarios

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    The implications of global mitigation to achieve different long-term temperature goals (LTTGs) can be investigated in integrated assessment models (IAMs), which provide a large number of outputs including technology deployment levels, economic costs, carbon prices, annual rates of decarbonisation, degree of global net negative emissions required, as well as utilisation levels for fossil fuel plants. All of these factors can be considered in detail when judging the real-world feasibility of the mitigation scenarios produced by these models. This study presents a model inter-comparison of three widely used IAMs (TIAM, MESSAGE and WITCH) to analyse multiple mitigation scenarios exploring a range of LTTGs and a range of constraints, including delayed mitigation action, limited end-use electrification and delayed deployment of carbon capture technologies. The scenario outputs across the three models are examined and discussed and a matrix of the different factors concerning scenario feasibility is presented
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