3,316 research outputs found

    Dual nozzle aerodynamic and cooling analysis study

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    Geometric, aerodynamic flow field, performance prediction, and heat transfer analyses are considered for two advanced chamber nozzle concepts applicable to Earth-to-orbit engine systems. Topics covered include improvements to the dual throat aerodynamic and performance prediction program; geometric and flow field analyses of the dual expander concept; heat transfer analysis of both concepts, and engineering analysis of data from the NASA/MSFC hot-fire testing of a dual throat thruster model thrust chamber assembly. Preliminary results obtained are presented in graphs

    Swirl coaxial injector element characterization for booster engines

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    Recent hot fire testing at the Marshall Space Flight Center (MSFC) has indicated the swirl-coaxial element to be a viable candidate for the STBE injector. Plans are to test the current 40K lbf thrust injector at the higher chamber pressure and colder fuel temperature which are anticipated for STBE. A cold flow program to characterize the swirl coax element over a range of operating points was conducted. The results are presented and compared to the hot fire data. Predictions for compatibility, performance and stability are then presented for the uprated test conditions

    Heterogene ouderenzorg in Scandinavië

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    De Nederlandse verzorgingsstaat verandert en om de transitie van verzorgingsstaat naar participatiesamenleving in goede banen te leiden wordt naar het buitenland gekeken. Het Scandinavische model heeft een voorbeeldfunctie, maar studenten van Professionshøjskolen Metropol (Kopenhagen) stellen de vraag of het Scandinavische model ooit voltooid en volledig uitgevoerd i

    Dual nozzle aerodynamic and cooling analysis study

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    Analytical models to predict performance and operating characteristics of dual nozzle concepts were developed and improved. Aerodynamic models are available to define flow characteristics and bleed requirements for both the dual throat and dual expander concepts. Advanced analytical techniques were utilized to provide quantitative estimates of the bleed flow, boundary layer, and shock effects within dual nozzle engines. Thermal analyses were performed to define cooling requirements for baseline configurations, and special studies of unique dual nozzle cooling problems defined feasible means of achieving adequate cooling

    China - electronic payment services : discrimination, economic development and the GATS

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    First published online on April 28, 2014Revised version of EUI RSCAS WP 2013/68; Global Governance Programme-66This paper provides a legal–economic analysis of the unappealed WTO Panel Report in China – Certain Measures Affecting Electronic Payment Services (WT/DS413/R). The core issue was whether China's measures that resulted in there being only one dominant supplier of electronic payment services (EPS) in China violated the specific commitments made by China under the GATS. The panel ruled that the measures did not violate China's market access commitments because there were no explicit limitations on the entry of foreign suppliers, but that the measures were inconsistent with China's national treatment commitments in that they modified the conditions of competition in favour of domestic suppliers. This case illustrates the complexity in interpreting WTO Members’ commitments under the GATS

    The minimum rank of universal adjacency matrices

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    In this paper we introduce a new parameter for a graph called the {\it minimum universal rank}. This parameter is similar to the minimum rank of a graph. For a graph GG the minimum universal rank of GG is the minimum rank over all matrices of the form U(α,β,γ,δ)=αA+βI+γJ+δD U(\alpha, \beta, \gamma, \delta) = \alpha A + \beta I + \gamma J + \delta D where AA is the adjacency matrix of GG, JJ is the all ones matrix and DD is the matrix with the degrees of the vertices in the main diagonal, and α0,β,γ,δ\alpha\neq 0, \beta, \gamma, \delta are scalars. Bounds for general graphs based on known graph parameters are given, as is a formula for the minimum universal rank for regular graphs based on the multiplicity of the eigenvalues of AA. The exact value of the minimum universal rank of some families of graphs are determined, including complete graphs, complete bipartite graph, paths and cycles. Bounds on the minimum universal rank of a graph obtained by deleting a single vertex are established. It is shown that the minimum universal rank is not monotone on induced subgraphs, but bounds based on certain induced subgraphs, including bounds on the union of two graphs, are given. Finally we characterize all graphs with minimum universal rank equal to 0 and to 1
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