11,434 research outputs found

    Cryogenic Propellant Scavenging

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    A detailed description of a computer model that has been developed for assessing the feasibility of low g cryogen propellant scavenging from the space shuttle External Tank (ET) is given. Either pump-assisted or pressure-induced propellant transfer may be selected. The program will accept a wide range of input variables, including the fuel to be transferred (LOX or LH2), heat leaks, tank temperatures, and piping and equipment specifications. The model has been parametrically analyzed to determine initial design specification for the system

    Lake sedimentological and ecological response to hyperthermals : Boltysh impact crater, Ukraine

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    Acknowledgements Initial drilling of the Boltysh meteorite crater was funded by Natural Environment Research Council (NERC) grant NE/D005043/1. The authors are extremely grateful to the valuable scientific contributions of S. Kelley and I. Gilmour. The constructive and critical reviews by M. Schuster and an anonymous reviewer greatly helped to improve this manuscript.Peer reviewedPostprin

    Continuous-wave Raman laser pumped within a semiconductor disk laser cavity

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    A KGd(WO4)(2) Raman laser was pumped within the cavity of a cw diode-pumped InGaAs semiconductor disk laser (SDL). The Raman laser threshold was reached for 5: 6W of absorbed diode pump power, and output power up to 0.8W at 1143nm, with optical conversion efficiency of 7.5% with respect to the absorbed diode pump power, was demonstrated. Tuning the SDL resulted in tuning of the Raman laser output between 1133 and 1157nm

    Perspectives on subnational carbon and climate footprints: A case study of Southampton, UK

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    Sub-national governments are increasingly interested in local-level climate change management. Carbon- (CO2 and CH4) and climate-footprints—(Kyoto Basket GHGs) (effectively single impact category LCA metrics, for global warming potential) provide an opportunity to develop models to facilitate effective mitigation. Three approaches are available for the footprinting of sub-national communities. Territorial-based approaches, which focus on production emissions within the geo-political boundaries, are useful for highlighting local emission sources but do not reflect the transboundary nature of sub-national community infrastructures. Transboundary approaches, which extend territorial footprints through the inclusion of key cross boundary flows of materials and energy, are more representative of community structures and processes but there are concerns regarding comparability between studies. The third option, consumption-based, considers global GHG emissions that result from final consumption (households, governments, and investment). Using a case study of Southampton, UK, this chapter develops the data and methods required for a sub-national territorial, transboundary, and consumption-based carbon and climate footprints. The results and implication of each footprinting perspective are discussed in the context of emerging international standards. The study clearly shows that the carbon footprint (CO2 and CH4 only) offers a low-cost, low-data, universal metric of anthropogenic GHG emission and subsequent management

    Compiling the space shuttle wind tunnel data base: An exercise in technical and managerial innovators

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    Engineers evaluating Space Shuttle flight data and performance results are using a massive data base of wind tunnel test data. A wind tunnel test data base of the magnitude attained is a major accomplishment. The Apollo program spawned an automated wind tunnel data analysis system called SADSAC developed by the Chrysler Space Division. An improved version of this system renamed DATAMAN was used by Chrysler to document analyzed wind tunnel data and data bank the test data in standardized formats. These analysis documents, associated computer graphics and standard formatted data were disseminated nationwide to the Shuttle technical community. These outputs became the basis for substantiating and certifying the flight worthiness of the Space Shuttle and for improving future designs. As an aid to future programs this paper documents the lessons learned in compiling the massive wind tunnel test data base for developing the Space Shuttle. In particular, innovative managerial and technical concepts evolved in the course of conceiving and developing this successful DATAMAN system and the methods and organization for applying the system are presented

    Preconstruction Plan for Stairs at West Cerro Vista Apartments

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    Students at California Polytechnic University have created an unsafe dirt trail down a hillside west of the Cerro Vista Apartment Complex on the university’s campus. This heavily traveled trail is a shortcut to an existing pedestrian pathway which connects Village Drive to Poly Canyon Village, as well as the R-3 and R-4 parking structures. The use of this trail raises alarm for potential safety concerns for students using it, especially during winter months when the hillside becomes very slippery. This paper outlines the design and preconstruction plan for the West Cerro Vista Stair Project, which proposes replacing the current trail with two independent concrete stairways. The scope of the preconstruction plan includes the preliminary design of the stairway, estimate of cost to construct, construction schedule, project cost forecast, site logistics plan, traffic control plan, risk hazard analysis, as well as a land acquisition and permitting plan. The purpose of this paper is to bring awareness of the safety concern with the existing trail, as well as provide a potential solution that may be continued into a final design phase and constructed in the proposed locatio
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