4,781 research outputs found

    Jettisoning system for a parachute's canister

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    Three-point automatically released suspension and jettisoning system operates independently of lander's power system and releases parachute on touchdown. The system is based on a ball-lock device operated by the shock of the parachute's opening and by the subsequent decay in the load on the main cord

    Separation of two bodies in space. A machine programmed analysis using the Lagrange equations and Eulerian angles

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    Fortran computer program and Lagrangian motion equations for separation analysis of two bodies in spac

    Separation of two bodies in space

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    Computer program analyzes the motion of two rigid bodies in space, separating as a result of any one, or a combination of, the following mechanisms - springs with ball ends, springs with one end guided, pyrotechnics, rockets, cold-gas jets, air pistons, and Coulomb drag

    Factorizing Numbers with the Gauss Sum Technique: NMR Implementations

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    Several physics-based algorithms for factorizing large number were recently published. A notable recent one by Schleich et al. uses Gauss sums for distinguishing between factors and non-factors. We demonstrate two NMR techniques that evaluate Gauss sums and thus implement their algorithm. The first one is based on differential excitation of a single spin magnetization by a cascade of RF pulses. The second method is based on spatial averaging and selective refocusing of magnetization for Gauss sums corresponding to factors. All factors of 16637 and 52882363 are successfully obtained.Comment: 4 pages, 4 figures; Abstract and Conclusion are slightly modified. References added and formatted with Bibte

    Development of mechanisms for a planetary landing parachute system

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    Development and testing of planetary landing parachute syste

    Detrimental adsorbate fields in experiments with cold Rydberg gases near surfaces

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    We observe the shift of Rydberg levels of rubidium close to a copper surface when atomic clouds are repeatedly deposited on it. We measure transition frequencies of rubidium to S and D Rydberg states with principal quantum numbers n between 31 and 48 using the technique of electromagnetically induced transparency. The spectroscopic measurement shows a strong increase of electric fields towards the surface that evolves with the deposition of atoms. Starting with a clean surface, we measure the evolution of electrostatic fields in the range between 30 and 300 \mum from the surface. We find that after the deposition of a few hundred atomic clouds, each containing ~10^6 atoms, the field of adsorbates reaches 1 V/cm for a distance of 30 \mum from the surface. This evolution of the electrostatic field sets serious limitations on cavity QED experiments proposed for Rydberg atoms on atom chips.Comment: 4 pages, 3 figures Submitted to Phys. Rev.

    Center vortex properties in the Laplace center gauge of SU(2) Yang-Mills theory

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    Resorting to the the Laplace center gauge (LCG) and to the Maximal-center gauge (MCG), respectively, confining vortices are defined by center projection in either case. Vortex properties are investigated in the continuum limit of SU(2) lattice gauge theory. The vortex (area) density and the density of vortex crossing points are investigated. In the case of MCG, both densities are physical quantities in the continuum limit. By contrast, in the LCG the piercing as well as the crossing points lie dense in the continuum limit. In both cases, an approximate treatment by means of a weakly interacting vortex gas is not appropriate.Comment: reference added, submitted to Phys. Lett.

    Signatures in a Giant Radio Galaxy of a Cosmological Shock Wave at Intersecting Filaments of Galaxies

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    Sensitive images of low-level, Mpc-sized radio cocoons offer new opportunities to probe large scale intergalactic gas flows outside clusters of galaxies. New radio images of high surface brightness sensitivity at strategically chosen wavelengths of the giant radio galaxy NGC 315 (Mack et al. 1997,1998) reveal significant asymmetries and particularities in the morphology, radio spectrum and polarization of the ejected radio plasma. We argue that the combination of these signatures provides a sensitive probe of an environmental shock wave. Analysis of optical redshifts in NGC 315 vicinity confirms its location to be near, or at a site of large-scale flow collisions in the 100 Mpc sized Pisces-Perseus Supercluster region. NGC 315 resides at the intersection of several galaxy filaments, and its radio plasma serves there as a `weather station' (Burns 1998) probing the flow of the elusive and previously invisible IGM gas. If our interpretation is correct, this is the first indication for a shock wave in flows caused by the cosmological large scale structure formation, which is located in a filament of galaxies. The possibility that the putative shock wave is a source of gamma-rays and ultra high energy cosmic rays is briefly discussed.Comment: accepted by Astrophysical Journal Letters, 4 pages, 3 figures (incl. 2 color), uses emulateapj5.sty (included), aastex.sty (included) and psfig.st

    Center Vortex Model for the Infrared Sector of SU(3) Yang-Mills Theory - Confinement and Deconfinement

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    The center vortex model for the infrared sector of Yang-Mills theory, previously studied for the SU(2) gauge group, is extended to SU(3). This model is based on the assumption that vortex world-surfaces can be viewed as random surfaces in Euclidean space-time. The confining properties are investigated, with a particular emphasis on the finite-temperature deconfining phase transition. The model predicts a very weak first order transition, in agreement with SU(3) lattice Yang-Mills theory, and also reproduces a consistent behavior of the spatial string tension in the deconfined phase. The geometrical structure of the center vortices is studied, including vortex branchings, which are a new property of the SU(3) case.Comment: 22 pages, 12 figures (30 eps-files), uses LaTeX package "psfrag
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