25,464 research outputs found

    Space fabrication: Graphite composite truss welding and cap forming subsystems

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    An automated beam builder for the fabrication of space structures is described. The beam builder forms a triangular truss 1.3 meters on a side. Flat strips of preconsolidated graphite fiber fabric in a polysulfone matrix are coiled in a storage canister. Heaters raise the material to forming temperature then the structural cap section is formed by a series of rollers. After cooling, cross members and diagonal tension cords are ultrasonically welded in place to complete the truss. The stability of fabricated structures and composite materials is also examined

    Indexed keyed connection Patent

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    Standard coupling design for mass productio

    Satellite Power System. Concept development and evaluation program, volume 6: Construction and operations

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    The construction, operation, and maintenance requirements for a solar power satellite, including the space and ground systems, are reviewed. The basic construction guidelines are explained, and construction location options are discussed. The space construction tasks, equipment, and base configurations are discussed together with the operations required to place a solar power satellite in geosynchronous orbit. A rectenna construction technique is explained, and operation with the grid is defined. Maintenance requirements are summarized for the entire system. Key technology issues required for solar power satellite construction operations are defined

    Thermal stress analysis of space shuttle orbiter wing skin panel and thermal protection system

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    Preflight thermal stress analysis of the space shuttle orbiter wing skin panel and the thermal protection system (TPS) was performed. The heated skin panel analyzed was rectangular in shape and contained a small square cool region at its center. The wing skin immediately outside the cool region was found to be close to the state of elastic instability in the chordwise direction based on the conservative temperature distribution. The wing skin was found to be quite stable in the spanwise direction. The potential wing skin thermal instability was not severe enough to tear apart the strain isolation pad (SIP) layer. Also, the preflight thermal stress analysis was performed on the TPS tile under the most severe temperature gradient during the simulated reentry heating. The tensile thermal stress induced in the TPS tile was found to be much lower than the tensile strength of the TPS material. The thermal bending of the TPS tile was not severe enough to cause tearing of the SIP layer

    Results of the 2004/2005 Hospice Patient Survey: General Report

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    The National Minimum Standards for Independent Healthcare, published in 2002 by the Care Standards Commission (now the Healthcare Commission) states that hospices are required to conduct an annual patient survey. In response to this, a Patient Survey group (with representation from independent hospices, Marie Curie Cancer Care and with input from the Care Standards Commission) was set up by Help the Hospices. Its goal was to develop a questionnaire suitable for use in all adult hospices

    Service Development Programme: Maximising Life Opportunities for Teenagers. Teenagers' Views and Experiences of Sex and Relationships Education, Sexual Health Services and Family Support Services in Kent - Survey findings for Year 2

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    This brief report provides findings from data collected in year 2 of a survey of teenagers' views and experiences of sex and relationships education and sexual health services in Kent. The data in year 2 was collected in Autumn 2005, a year after the data collected in year 1. The purpose of this report is to highlight the results in year 2 which differ from the year 1 survey data. It is to be used in conjunction with the report in year 1 entitled "Service Development Programme: Maximising Life Opportunies for Teenagers: Teenagers' Views and Experiences of Sex and Relationships Educatioon, Sexual Health Services and Family Suupport Services in Kent: Survey Findings July 2005". The final report on the survey will consist of findings from further analysis of the data from year 1 and year 2 merged together, available at the end of 2006

    Decuplet baryon magnetic moments in a QCD-based quark model beyond quenched approximation

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    We study the decuplet baryon magnetic moments in a QCD-based quark model beyond quenched approximation. Our approach for unquenching the theory is based on the heavy baryon perturbation theory in which the axial couplings for baryon - meson and the meson-meson-photon couplings from the chiral perturbation theory are used together with the QM moment couplings. It also involves the introduction of a form factor characterizing the structure of baryons considered as composite particles. Using the parameters obtained from fitting the octet baryon magnetic moments, we predict the decuplet baryon magnetic moments. The Ω\Omega^- magnetic moment is found to be in good agreement with experiment: μΩ\mu_{\Omega^-} is predicted to be 1.97μN-1.97 \mu_N compared to the experimental result of (-2.02 ±\pm 0.05) μN\mu_N.Comment: 19 pages, 2 figure

    Analysis of General Power Counting Rules in Effective Field Theory

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    We derive the general counting rules for a quantum effective field theory (EFT) in d\mathsf{d} dimensions. The rules are valid for strongly and weakly coupled theories, and predict that all kinetic energy terms are canonically normalized. They determine the energy dependence of scattering cross sections in the range of validity of the EFT expansion. We show that the size of cross sections is controlled by the Λ\Lambda power counting of EFT, not by chiral counting, even for chiral perturbation theory (χ\chiPT). The relation between Λ\Lambda and ff is generalized to d\mathsf{d} dimensions. We show that the naive dimensional analysis 4π4\pi counting is related to \hbar counting. The EFT counting rules are applied to χ\chiPT, low-energy weak interactions, Standard Model EFT and the non-trivial case of Higgs EFT.Comment: V2: more details and examples added; version published in journal. 17 pages, 4 figures, 2 table
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