25,227 research outputs found

    Planetary/DOD entry technology flight experiments. Volume 3: Planetary entry flight experiments handbook

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    The environments produced by entry into Jupiter and Saturn atmospheres are summarized. Worst case design environments are identified and the effect of entry angle, type of atmosphere and ballistic coefficient variations are presented. The range of environments experienced during earth entry is parametrically described as a function of initial entry conditions. The sensitivity of these environments to vehicle ballistic coefficient and nose radius is also shown. An elliptical deorbit maneuver strategy is defined in terms of the velocity increment required versus initial entry conditions and apoapsis altitude. Mission time, ground track, and out of plane velocity penalties are also presented. Performance capabilities of typical shuttle launched boosters are described including the initial entry conditions attainable as a function of paylaod mass and apoapsis altitude

    Planetary/DOD entry technology flight experiments. Volume 1: Executive summary

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    The feasibility of using the space shuttle to launch planetary and DoD entry flight experiments was examined. The results of the program are presented in two parts: (1) simulating outer planet environments during an earth entry test, the prediction of Jovian and earth radiative heating dominated environments, mission strategy, booster performance and entry vehicle design, and (2) the DoD entry test needs for the 1980's, the use of the space shuttle to meet these DoD test needs, modifications of test procedures as pertaining to the space shuttle, modifications to the space shuttle to accommodate DoD test missions and the unique capabilities of the space shuttle. The major findings of this program are summarized

    Interface of the polarizable continuum model of solvation with semi-empirical methods in the GAMESS program

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    An interface between semi-empirical methods and the polarized continuum model (PCM) of solvation successfully implemented into GAMESS following the approach by Chudinov et al (Chem. Phys. 1992, 160, 41). The interface includes energy gradients and is parallelized. For large molecules such as ubiquitin a reasonable speedup (up to a factor of six) is observed for up to 16 cores. The SCF convergence is greatly improved by PCM for proteins compared to the gas phase

    A study of quantum decoherence in a system with Kolmogorov-Arnol'd-Moser tori

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    We present an experimental and numerical study of the effects of decoherence on a quantum system whose classical analogue has Kolmogorov-Arnol'd-Moser (KAM) tori in its phase space. Atoms are prepared in a caesium magneto-optical trap at temperatures and densities which necessitate a quantum description. This real quantum system is coupled to the environment via spontaneous emission. The degree of coupling is varied and the effects of this coupling on the quantum coherence of the system are studied. When the classical diffusion through a partially broken torus is < hbar, diffusion of quantum particles is inhibited. We find that increasing decoherence via spontaneous emission increases the transport of quantum particles through the boundary.Comment: 19 pages including 6 figure

    77Se NMR Investigation of the K(x)Fe(2-y)Se(2) High Tc Superconductor (Tc=33K)

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    We report a comprehensive 77Se NMR study of the structural, magnetic, and superconducting properties of a single crystalline sample of the newly discovered FeSe-based high temperature superconductor K(x)Fe(2-y)Se(2) (Tc=33K) in a broad temperature range up to 290 K. We will compare our results with those reported for FeSe (Tc=9K) and FeAs-based high Tc systems.Comment: Final versio

    Blister Beetles in Alfalfa

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    Blister beetles are Iong cylindrical beetles that may be black, gray, yellow and brown striped, black with gray margins on the wing covers or black with a red head. These insects are usually found feeding in clusters on alfalfa. They can cause severe sickness and sometimes death when livestock especially horses eat the live or dead beetles. They are usually not found in alfalfa in mid-July and early August which translates to the third or fourth cutting. Blister beetles (black ones, gray margined ones, and yellow striped ones) were collected in very noticeable numbers in several central Kentucky alfalfa fields this past summer. The most commonly found species is the margined blister beetle. This insect has a black head and body with a gray margin around the wing covers. They range in size from 3/4 to 1 inch. Other species that are also found but do not seem as common include the red-headed blister beetle, the striped blister beetle and the black blister beetle. When found in alfalfa, blister beetles are usually on the very tops of the plants and most often found feeding on the blossoms. Timely harvest, before bloom occurs, is useful in preventing the attraction of these beetles to the field

    Environmental control study of space vehicles. Part III - Thermal control techniques and systems

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    General analysis for space vehicle thermal control systems and technique

    ADIPLS -- the Aarhus adiabatic oscillation package

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    Development of the Aarhus adiabatic pulsation code started around 1978. Although the main features have been stable for more than a decade, development of the code is continuing, concerning numerical properties and output. The code has been provided as a generally available package and has seen substantial use at a number of installations. Further development of the package, including bringing the documentation closer to being up to date, is planned as part of the HELAS Coordination Action.Comment: Astrophys. Space Sci., in the pres

    Outcome from Spontaneous CP Violation for B Decays

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    In the aspon model solution of the strong CPCP problem, there is a gauged U(1)U(1) symmetry, spontaneously broken by the same vacuum expectation value which breaks CPCP, whose massive gauge boson provides an additional mechanism of weak CPCP violation. We calculate the CPCP asymmetries in BB decays for the aspon model and show that they are typically smaller than those predicted from the standard model. A linear relation between the CPCP asymmetries of different decay processes is obtained.Comment: REVTEX, 9 pages, IFP-486-UNC, NSF-PT-94-1, and UDHEP-01-9
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