2,962 research outputs found

    Effects of reaction control system jet simulation on the stability and control characteristics of a 0.015-scale space shuttle orbiter model in the Ames Research Center 3.5-foot hypersonic wind tunnel

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    An experimental investigation was performed in the Ames Research Center 3.5-Foot Hypersonic Wind Tunnel to obtain detailed effects which interactions between the RCS jet flow field and the local orbiter flow field have on orbiter hypersonic stability and control characteristics. Six-component force data were obtained through an angle-of-attack range of 15 to 35 deg with 0 deg angle of sideslip. The test was conducted with yaw, pitch and roll jet simulation at a free-stream Mach number of 10.3. These data simulate two SSV reentry flight conditions at Mach numbers of 28.3 and 10.3. Fuselage base pressures and pressures on the nonmetric RCS pods were obtained in addition to the basic force measurements. Model 42-0 was used for these tests

    Results of tests of a 0.010- and 0.015-scale models of space shuttle orbiter configurations 3 and 3A in the Ames Research Center 3.5 foot hypersonic wind tunnel (OA23)

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    Longitudinal and lateral-directional stability and control characteristics were evaluated at Mach numbers of 5.3, 7.3 and 10.3 at angles of attack up to 50 degrees with Beta = 0 degrees and, for a few cases, Beta = 5 degrees. Component force data, fuselage base pressures and shadowgraph patterns were recorded

    English and Welsh Civil and Social Justice Panel Survey: Wave 1. Findings and Technical Report

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    The ability of people to protect their legal rights and hold others to their legal responsibilities is a prerequisite of the rule of law and underpins social justice. The English and Welsh Civil and Social Justice Panel Survey (CSJPS), which replaced the English and Welsh Civil and Social Justice Survey (CSJS) in 2010, provides the only large-scale representative overview of the public’s experience of civil justice issues and successes in seeking justice when addressing them. This overview report describes the main findings from the first wave of the English and Welsh Civil and Social Justice Panel Survey, as well as setting out the full technical details of the survey

    First Season QUIET Observations: Measurements of Cosmic Microwave Background Polarization Power Spectra at 43 GHz in the Multipole Range 25 ≤ ℓ ≤ 475

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    The Q/U Imaging ExperimenT (QUIET) employs coherent receivers at 43 GHz and 94 GHz, operating on the Chajnantor plateau in the Atacama Desert in Chile, to measure the anisotropy in the polarization of the cosmic microwave background (CMB). QUIET primarily targets the B modes from primordial gravitational waves. The combination of these frequencies gives sensitivity to foreground contributions from diffuse Galactic synchrotron radiation. Between 2008 October and 2010 December, over 10,000 hr of data were collected, first with the 19 element 43 GHz array (3458 hr) and then with the 90 element 94 GHz array. Each array observes the same four fields, selected for low foregrounds, together covering ≈1000 deg^2. This paper reports initial results from the 43 GHz receiver, which has an array sensitivity to CMB fluctuations of 69 μK√s. The data were extensively studied with a large suite of null tests before the power spectra, determined with two independent pipelines, were examined. Analysis choices, including data selection, were modified until the null tests passed. Cross-correlating maps with different telescope pointings is used to eliminate a bias. This paper reports the EE, BB, and EB power spectra in the multipole range ℓ = 25-475. With the exception of the lowest multipole bin for one of the fields, where a polarized foreground, consistent with Galactic synchrotron radiation, is detected with 3σ significance, the E-mode spectrum is consistent with the ΛCDM model, confirming the only previous detection of the first acoustic peak. The B-mode spectrum is consistent with zero, leading to a measurement of the tensor-to-scalar ratio of r = 0.35^(+1.06)_(–0.87). The combination of a new time-stream "double-demodulation" technique, side-fed Dragonian optics, natural sky rotation, and frequent boresight rotation leads to the lowest level of systematic contamination in the B-mode power so far reported, below the level of r = 0.1

    The Effect Of Sample Size On The Heat Release Rate Of Charring Materials

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    BIOMECHANIC OF BALANCE:PARADIGMS AND PROCEDURES

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    Balance, like coordination, is understood by virtually everyone to be a critical component of skillful movement. Yet there exists very little biomechanical research into how balance is employed and improved by performers of disparate abilities in different sports. The purpose of this symposium is to open a dialogue on the biomechanics of balance. The first part of the symposium will be an exposition of definitions and conceptions of balance from the literature. While most of the traditional approaches provide clarity on some aspect of balance, not one is broad enough to encompass the diversity of contexts and proficiencies in sport. By combining features of many approaches and elaborating on the false dichotomies (e.g., static vs. dynamic), we propose a more contemporary conception of balance which deals with the interplay of stability and mobility of the body with respect to its base of support. Depending on the sporting context, more stability than mobility may be desired, and depending on the skill level of the performer, more instability than stability may be apparent. There are many ways to operationalize stability and mobility: for example, using video, we can measure the position and movement of the line of gravity with respect to the base of support, and using a force plate, we can assess the A/P and M/L forces and the center of pressure. The second part of the symposium will be an exploration of balance using the stability/mobility paradigm and procedures. Specifically we will compare intermediate and advanced performers in four sports skills: In the basketball jump shot, which requires great A/P stability over a small base of support, higher skill was associated with less in stability. In the volleyball spike, which requires arrested mobility as the horizontal approach is transformed into the vertical jump, higher skill was associated with greater reduction in mobility. In the golf pitch shot, which requires little mobility in either the A/P or M/L directions, higher skill was associated with less mobility. In the weight lifting snatch, which requires an early horizontal movement of the bar followed by relative stability, lower skill was associated with greater stability. Given that the snatch also has a perceptible risk of injury, this finding is not surprising. Following a summary, the audience will be invited to participate in a discussion on the biomechanics of balance

    Reconfiguration on sparse graphs

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    A vertex-subset graph problem Q defines which subsets of the vertices of an input graph are feasible solutions. A reconfiguration variant of a vertex-subset problem asks, given two feasible solutions S and T of size k, whether it is possible to transform S into T by a sequence of vertex additions and deletions such that each intermediate set is also a feasible solution of size bounded by k. We study reconfiguration variants of two classical vertex-subset problems, namely Independent Set and Dominating Set. We denote the former by ISR and the latter by DSR. Both ISR and DSR are PSPACE-complete on graphs of bounded bandwidth and W[1]-hard parameterized by k on general graphs. We show that ISR is fixed-parameter tractable parameterized by k when the input graph is of bounded degeneracy or nowhere-dense. As a corollary, we answer positively an open question concerning the parameterized complexity of the problem on graphs of bounded treewidth. Moreover, our techniques generalize recent results showing that ISR is fixed-parameter tractable on planar graphs and graphs of bounded degree. For DSR, we show the problem fixed-parameter tractable parameterized by k when the input graph does not contain large bicliques, a class of graphs which includes graphs of bounded degeneracy and nowhere-dense graphs

    Wind tunnel test of the 0.010-scale space shuttle integrated vehicle in the NASA-Ames 3.5 foot hypersonic wind tunnel (IA10)

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    Experimental aerodynamic investigations were conducted in the NASA Ames Research Center 3.5-Foot Hypersonic Wind Tunnel on a 0.010-scale model of the space shuttle vehicle orbiter and external tank (model no. 32 0T). The purpose of the test was to evaluate the basic hypersonic stability characteristics of the external tank and orbiter and to define orbiter plume effects on aero characteristics using solid plumes. The test was conducted at angles of attack from minus 10 deg to 30 deg and angles of sideslip of minus 10 deg thru 10 deg. Six component force data and static base pressures were recorded during the test

    The Q/U Imaging Experiment: Polarization Measurements of the Galactic Plane at 43 and 95 GHz

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    We present polarization observations of two Galactic plane fields centered on Galactic coordinates (l, b) = (0°, 0°) and (329°, 0°) at both Q (43 GHz) and W bands (95 GHz), covering between 301 and 539 square degrees depending on frequency and field. These measurements were made with the QUIET instrument between 2008 October and 2010 December, and include a total of 1263 hr of observations. The resulting maps represent the deepest large-area Galactic polarization observations published to date at the relevant frequencies with instrumental rms noise varying between 1.8 and 2.8 μK deg, 2.3–6 times deeper than corresponding WMAP and Planck maps. The angular resolution is 27!3 and 12!8 FWHM at Q and W bands, respectively. We find excellent agreement between the QUIET and WMAP maps over the entire fields, and no compelling evidence for significant residual instrumental systematic errors in either experiment, whereas the Planck 44 GHz map deviates from these in a manner consistent with reported systematic uncertainties for this channel. We combine QUIET and WMAP data to compute inverse-variance-weighted average maps, effectively retaining small angular scales from QUIET and large angular scales from WMAP. From these combined maps, we derive constraints on several important astrophysical quantities, including a robust detection of polarized synchrotron spectral index steepening of ≈0.2 off the plane, as well as the Faraday rotation measure toward the Galactic center (RM = −4000 ± 200 rad m^(−2)), all of which are consistent with previously published results. Both the raw QUIET and the co-added QUIET+WMAP maps are made publicly available together with all necessary ancillary information

    Mixed-state quasiparticle transport in high-T_c cuprates: localization by magnetic field

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    Theory of quasiparticle transport in the mixed state of a d-wave superconductor is developed under the assumption of disordered vortex array. A novel universal regime is identified at fields above H*= c*H_{c2}(T/T_c)^2, characterized by a field-independent longitudinal thermal conductivity. It is argued that this behavior is responsible for the high-field plateau in the thermal conductivity experimentally observed in cuprates by Krishana, Ong and co-workers.Comment: 4 pages REVTeX + 1 PostScript figure. Final version to appear in PRL. Several changes in response to referee comments. For related work and info visit http://www.pha.jhu.edu/~fran
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