4,703 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

    A Strategic Approach to Agricultural Research Program Planning in Sub-Saharan Africa

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    Recent studies have shown that agricultural research can have high payoffs in Africa, but impact depends on how well technology fits with evolving needs and capacity in the agricultural sector and the rest of the economy. Structural adjustment policies (e.g., market liberalization, currency devaluation) and political change are transforming user demands for new technology and the economic environment in which technology must perform. The challenge is how to design agricultural research as a strategic input to promote broad-based economic growth, structural transformation, and food security in the increasingly market-driven, but fragile, economies of Africa.Food Security, Food Policy, Agricultural Research, Research and Development/Tech Change/Emerging Technologies, Downloads May 2008-July 2009: 44, Q18,

    A Strategic Approach to Agricultural Research Program Planning in Sub-Saharan Africa

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    Research and Development/Tech Change/Emerging Technologies, Downloads May 2008-July 2009: 13,

    The in Vitro Respiration of Nerve

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    Low Frequency Tilt Seismology with a Precision Ground Rotation Sensor

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    We describe measurements of the rotational component of teleseismic surface waves using an inertial high-precision ground-rotation-sensor installed at the LIGO Hanford Observatory (LHO). The sensor has a noise floor of 0.4 nrad/Hz/ \sqrt{\rm Hz} at 50 mHz and a translational coupling of less than 1 μ\murad/m enabling translation-free measurement of small rotations. We present observations of the rotational motion from Rayleigh waves of six teleseismic events from varied locations and with magnitudes ranging from M6.7 to M7.9. These events were used to estimate phase dispersion curves which shows agreement with a similar analysis done with an array of three STS-2 seismometers also located at LHO

    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
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