3,673 research outputs found

    The bond stress in a viscoelastic propellant disk during thermal shock

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    Analysis of bond stress in viscoelastic case bonded solid propellant rocket assembly during thermal shoc

    Thermal stresses in chemically hardening elastic media with application to the molding process

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    Thermal stresses in chemically hardened elastic media and applications to molding processe

    Transient temperature distribution during an exothermic chemical reaction

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    Heat conduction equation for determining temperature distribution during exothermic chemical reactio

    Residual stresses developed in molding a flat sheet of a chemically-hardening relatively incompressible material

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    Approximation of residual thermal stresses in flat sheet molded from chemical hardening material

    Effects of systematic errors on the mixing ratios of trace gases obtained from occulation spectra

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    The influence of systematic errors in the parameters of the models describing the geometry and the atmosphere on the profiles of trace gases retrieved from simulated solar occultation spectra, collected at satellite altitudes, is investigated. Because of smearing effects and other uncertainties, it may be preferable to calibrate the spectra internally by measuring absorption lines of an atmospheric gas such as CO2 whose vertical distribution is assumed rather than to relay on externally supplied information

    Meteoroid hazards in deep space Final report

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    Design and development of Sisyphus meteoroid detection system for interplanetary spacecraf

    Rydberg trimers and excited dimers bound by internal quantum reflection

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    Quantum reflection is a pure wave phenomena that predicts reflection of a particle at a changing potential for cases where complete transmission occurs classically. For a chemical bond, we find that this effect can lead to non-classical vibrational turning points and bound states at extremely large interatomic distances. Only recently has the existence of such ultralong-range Rydberg molecules been demonstrated experimentally. Here, we identify a broad range of molecular lines, most of which are shown to originate from two different novel sources: a single-photon associated triatomic molecule formed by a Rydberg atom and two ground state atoms and a series of excited dimer states that are bound by a so far unexplored mechanism based on internal quantum reflection at a steep potential drop. The properties of the Rydberg molecules identified in this work qualify them as prototypes for a new type of chemistry at ultracold temperatures.Comment: 6 pages, 3 figures, 1 tabl

    Irreversibility and Polymer Adsorption

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    Physisorption or chemisorption from dilute polymer solutions often entails irreversible polymer-surface bonding. We present a theory of the non-equilibrium layers which result. While the density profile and loop distribution are the same as for equilibrium layers, the final layer comprises a tightly bound inner part plus an outer part whose chains make only fN surface contacts where N is chain length. The contact fractions f follow a broad distribution, P(f) ~ f^{-4/5}, in rather close agreement with strong physisorption experiments [H. M. Schneider et al, Langmuir v.12, p.994 (1996)].Comment: 4 pages, submitted to Phys. Rev. Let

    The New Albany Shale gas play in southern Indiana

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    This poster was presented at the 2006 Eastern Section American Association of Petroleum Geologists, 35th Annual Meeting, in Buffalo, N.Y., October 8-11, 2006.The New Albany Shale (Devonian and Mississippian) in Indiana is mostly brownish-black organic-rich shale with lesser greenish-gray shale. The formation is 100 to 140 feet thick in southeastern Indiana and dips and thickens to the southwest into the Illinois Basin, where it attains a thickness of more than 360 feet in Posey County. Gas production from New Albany Shale began in 1885 and drilling activity continued into the 1930s, when interest waned in favor of more lucrative opportunities elsewhere. Renewed activity, driven by higher gas prices, has been brisk since the mid-1990s, witnessed by the completion of more than 400 productive wells. The majority of these wells were drilled in Harrison County, where production typically occurs at depths from 500 to 1,100 feet and production rates generally range from 20 to 450 MCFGPD. In the past 2 years, Daviess County and surrounding areas have become the focus of New Albany exploration after the El Paso Production No. 2-10 Peterson horizontal discovery well was rumored to have tested 1.3 MMCFGPD at an approximate measured depth of 2,200 feet. New Albany production is mostly from the organic-rich Clegg Creek Member. Gas compositions (C1-C4 and CO2) and carbon and hydrogen isotopic signatures indicate that both purely thermogenic and mixed thermogenic and biogenic gases are produced from the New Albany. Produced water ranges from brine to water diluted through recharge by modern precipitation; the brine zones contain primarily thermogenic gas and the diluted water zones contain gas of mixed thermogenic and biogenic origin

    Simultaneous Magneto-Optical Trapping of Two Lithium Isotopes

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    We confine 4 10^8 fermionic 6Li atoms simultaneously with 9 10^9 bosonic 7Li atoms in a magneto-optical trap based on an all-semiconductor laser system. We optimize the two-isotope sample for sympathetic evaporative cooling. This is an essential step towards the production of a quantum-degenerate gas of fermionic lithium atoms.Comment: 4 pages, 3 figure
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