3,736 research outputs found

    Static aerodynamic characteristics of the S-IC booster/GAC H-33 orbiter launch vehicle configuration

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    This test at the trisonic tunnel was divided into two parts. The first part utilized the H-33 orbiter with drop tanks and cradle mounted on an S-IC booster with 75 square-foot fins oriented 45 deg off the horizontal and vertical reference planes. Runs were initially made to determine the optimum incidence angle to be used for the remainder of the tests. The angle so determined was 0 degrees. Additional testing was performed with drop tanks removed, orbiter vertical tail removed, drop tanks and orbiter wing removed, booster fins removed and booster fins located in the horizontal and vertical reference planes. The second part utilized the H-33 orbiter and cradle only, sting mounted on a strain gage balance. These data were used in conjunction with test number 504 (orbiter alone on balance) to determine cradle effects

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    Space shuttle: Aerodynamic characteristics of a composite booster/040A orbiter launch configuration with fin and booster body configuration effect contribution

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    An investigation was made of the fin configuration and booster body configuration effects on a composite booster/040A orbiter launch configuration. Aerodynamic performance and stability characteristics in pitch and yaw were obtained. Configurations tested included two stepped cylindrical bodies of different lengths with a conical nose, four fin shapes of various sizes and aspect ratios mounted in different positions around the base of the bodies, two base flare angles and three 040A orbiter configurations. The orbiter variations included a tailless configuration and two tail sizes. A tailless booster launch configuration with deflected petals (expanded flare sectors) was also tested. The model scale was 0.003366. Data were converted to coefficient form in near real time, punched on cards, and tabulated. The cards used in conjunction with a Benson-Lehner plotter were used to provide plotted data. At the end of the test, tabulated input forms were completed for the SADSAC computer program to aid in publishing the final test data report

    Forebody and vertical stabilizer effects on directional stability of a reusable LOX/RP (061) booster AR 12161-2

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    Results are presented of a wind tunnel test on the directional stability of space shuttle booster configurations. The test was conducted at the 14-inch trisonic tunnel starting 6 December 1971 and continued through 11 December 1971 for a total of 66 occupancy hours. Configurations tested included a cylindrical body with two axisymmetrical noses, one with and without canopy, one delta wing, located in two positions, five vertical tails (including a V tail), two having split rudders, ventral fins, two sets of chines, three airbreathing engine pods, and rocket engine shrouds. The model scale was 0.003366

    Viewpoint consistency in Z and LOTOS: A case study

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    Specification by viewpoints is advocated as a suitable method of specifying complex systems. Each viewpoint describes the envisaged system from a particular perspective, using concepts and specification languages best suited for that perspective. Inherent in any viewpoint approach is the need to check or manage the consistency of viewpoints and to show that the different viewpoints do not impose contradictory requirements. In previous work we have described a range of techniques for consistency checking, refinement, and translation between viewpoint specifications, in particular for the languages LOTOS and Z. These two languages are advocated in a particular viewpoint model, viz. that of the Open Distributed Processing (ODP) reference model. In this paper we present a case study which demonstrates how all these techniques can be combined in order to show consistency between a viewpoint specified in LOTOS and one specified in Z. Keywords: Viewpoints; Consistency; Z; LOTOS; ODP

    The State of Preschool 2007

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    Provides data on state-funded pre-K programs for the 2006-2007 school year, such as percentages of children enrolled at different ages, spending per child, and the number of quality standard benchmarks met. Includes state rankings and profiles

    Race and Socioeconomic Status Differences in Study Abroad Participation: The Role of Habitus, Social Networks, and Cultural Capital

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    This study examines how race and socioeconomic status contribute to disparities in study abroad participation. Our mixed methods approach provides a broad overview of the selection process into study abroad using national data. It also provides a nuanced understanding of the mechanisms that perpetuate inequality among Black and lower class students. Both quantitative and qualitative results show that students’ habits, social networks, and cultural capital shape their study abroad experiences. We find that students with a positive predisposition toward internationalization (having foreign-born parents and/or experiencing different cultures overseas) were more likely to study abroad.Whites and high socioeconomic status students were also more likely to have family and friends who valued study abroad than were lower socioeconomic status and Black students. These advantaged students were better able to acquire and use cultural capital when accessing information from institutional agents. They were also more likely to possess the knowledge and background that complied with institutional standards. These factors contributed significantly to the race and class disparities in study abroad participation. This study contributes to the scant literature on study abroad by revealing mechanisms through which the reproduction of inequality is shaped in the university setting. We argue that patterns found to apply to this process are likely to take place in other processes in higher education as well

    On the Change in Archivability of Websites Over Time

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    As web technologies evolve, web archivists work to keep up so that our digital history is preserved. Recent advances in web technologies have introduced client-side executed scripts that load data without a referential identifier or that require user interaction (e.g., content loading when the page has scrolled). These advances have made automating methods for capturing web pages more difficult. Because of the evolving schemes of publishing web pages along with the progressive capability of web preservation tools, the archivability of pages on the web has varied over time. In this paper we show that the archivability of a web page can be deduced from the type of page being archived, which aligns with that page's accessibility in respect to dynamic content. We show concrete examples of when these technologies were introduced by referencing mementos of pages that have persisted through a long evolution of available technologies. Identifying these reasons for the inability of these web pages to be archived in the past in respect to accessibility serves as a guide for ensuring that content that has longevity is published using good practice methods that make it available for preservation.Comment: 12 pages, 8 figures, Theory and Practice of Digital Libraries (TPDL) 2013, Valletta, Malt

    Some useful techniques for pointwise and local error estimates of the quantities of interest in the finite element approximation

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    In this paper we review some existing techniques to obtain pointwise and local a posteriori error estimates for the quantities of interest in finite element approximations by using duality arguments. We also present a new approach to obtain computable error bounds for the recovered pointwise quantities. The new method is extended to include the practically important case of non-homogeneous Dirichlet data. Existing methods require purely Neumann data, or the Dirichlet data to be homogeneous. The new techniques are developed here to provide computable error bounds on the genuine pointwise quantities and allow the use of non-homogeneous Dirichlet data. The strength and weakness of each technique will be analysed and compared. The numerical experiments to justify our analysis will be presented

    An experimental and computational study of tip clearance effects on a transonic turbine stage

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    This paper describes an experimental and computational investigation into the influence of tip clearance on the blade tip heat load of a high-pressure (HP) turbine stage. Experiments were performed in the Oxford Rotor facility which is a 1½ stage, shroudless, transonic, high pressure turbine. The experiments were conducted at an engine representative Mach number and Reynolds number. Rotating frame instrumentation was used to capture both aerodynamic and heat flux data within the rotor blade row. Two rotor blade tip clearances were tested (1.5% and 1.0% of blade span). The experiments were compared with computational fluid dynamics (CFD) predictions made using a steady Reynolds-averaged Navier–Stokes (RANS) solver. The experiments and computational predictions were in good agreement. The blade tip heat transfer was observed to increase with reduced tip gap in both the CFD and the experiment. The augmentation of tip heat load at smaller clearances was found to be due to the ingestion of high relative total temperature fluid near the casing, generated through casing shear.This work was sponsored by Rolls-Royce plc and the Isle of Man Government.This is the author accepted manuscript. The final version is available from Elsevier via http://dx.doi.org/10.1016/j.ijheatfluidflow.2015.09.00
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