22,527 research outputs found
Planetary/DOD entry technology flight experiments. Volume 3: Planetary entry flight experiments handbook
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
Interface of the polarizable continuum model of solvation with semi-empirical methods in the GAMESS program
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
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)
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
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
General analysis for space vehicle thermal control systems and technique
Morphology of High-Multiplicity Events in Heavy Ion Collisions
We discuss opportunities that may arise from subjecting high-multiplicity
events in relativistic heavy ion collisions to an analysis similar to the one
used in cosmology for the study of fluctuations of the Cosmic Microwave
Background (CMB). To this end, we discuss examples of how pertinent features of
heavy ion collisions including global characteristics, signatures of collective
flow and event-wise fluctuations are visually represented in a Mollweide
projection commonly used in CMB analysis, and how they are statistically
analyzed in an expansion over spherical harmonic functions. If applied to the
characterization of purely azimuthal dependent phenomena such as collective
flow, the expansion coefficients of spherical harmonics are seen to contain
redundancies compared to the set of harmonic flow coefficients commonly used in
heavy ion collisions. Our exploratory study indicates, however, that these
redundancies may offer novel opportunities for a detailed characterization of
those event-wise fluctuations that remain after subtraction of the dominant
collective flow signatures. By construction, the proposed approach allows also
for the characterization of more complex collective phenomena like higher-order
flow and other sources of fluctuations, and it may be extended to the
characterization of phenomena of non-collective origin such as jets.Comment: Matches version accepted for publication in Physical Review C. 13
pages, 9 figure
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