28,669 research outputs found

    Tool pre-tensions covers prior to lacing

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    In securing a bulky object in a storage compartment, a cinching or tightening tool is used to draw two opposing cover halves together at a predetermined tension to permit quick lacing to retain the stored object. This tool is also useful in fabrication industries to draw components together during assembly or treating

    2H and 13C NMR studies on the temperature-dependent water and protein dynamics in hydrated elastin, myoglobin and collagen

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    2H NMR spin-lattice relaxation and line-shape analyses are performed to study the temperature-dependent dynamics of water in the hydration shells of myoglobin, elastin, and collagen

    Origin of non-exponential relaxation in a crystalline ionic conductor: a multi-dimensional 109Ag NMR study

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    The origin of the non-exponential relaxation of silver ions in the crystalline ion conductor Ag7P3S11 is analyzed by comparing appropriate two-time and three-time 109Ag NMR correlation functions. The non-exponentiality is due to a rate distribution, i.e., dynamic heterogeneities, rather than to an intrinsic non-exponentiality. Thus, the data give no evidence for the relevance of correlated back-and-forth jumps on the timescale of the silver relaxation.Comment: 4 pages, 3 figure

    Reactor antineutrino spectra and their application to antineutrino-induced reactions. II

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    The antineutrino and electron spectra associated with various nuclear fuels are calculated. While there are substantial differences between the spectra of different uranium and plutonium isotopes, the dependence on the energy and flux of the fission-inducing neutrons is very weak. The resulting spectra can be used for the calculation of the antineutrino and electron spectra of an arbitrary nuclear reactor at various stages of its refueling cycle. The sources of uncertainties in the spectrum are identified and analyzed in detail. The exposure time dependence of the spectrum is also discussed. The averaged cross sections of the inverse neutron ÎČ decay, weak charged and neutral-current-induced deuteron disintegration, and the antineutrino-electron scattering are then evaluated using the resulting Μ̅_e spectra. [RADIOACTIVITY, FISSION 235U, 238U, (^239)Pu, (^240)Pu, (^241)Pu, antineutrino and electron spectra calculated. σ for Μ̅ induced reactions analyzed.

    Kinetostatic Analysis and Solution Classification of a Planar Tensegrity Mechanism

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    Tensegrity mechanisms have several interesting properties that make them suitable for a number of applications. Their analysis is generally challenging because the static equilibrium conditions often result in complex equations. A class of planar one-degree-of-freedom (dof) tensegrity mechanisms with three linear springs is analyzed in detail in this paper. The kinetostatic equations are derived and solved under several loading and geometric conditions. It is shown that these mechanisms exhibit up to six equilibrium configurations, of which one or two are stable. Discriminant varieties and cylindrical algebraic decomposition combined with Groebner base elimination are used to classify solutions as function of the input parameters.Comment: 7th IFToMM International Workshop on Computational Kinematics, May 2017, Poitiers, France. 201

    Caging dynamics in a granular fluid

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    We report an experimental investigation of the caging motion in a uniformly heated granular fluid, for a wide range of filling fractions, ϕ\phi. At low ϕ\phi the classic diffusive behavior of a fluid is observed. However, as ϕ\phi is increased, temporary cages develop and particles become increasingly trapped by their neighbors. We statistically analyze particle trajectories and observe a number of robust features typically associated with dense molecular liquids and colloids. Even though our monodisperse and quasi-2D system is known to not exhibit a glass transition, we still observe many of the precursors usually associated with glassy dynamics. We speculate that this is due to a process of structural arrest provided, in our case, by the presence of crystallization.Comment: 4 pages, 5 figures, submitted to Phys. Rev. Let

    A mobile antineutrino detector with plastic scintillators

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    We propose a new type segmented antineutrino detector made of plastic scintillators for the nuclear safeguard application. A small prototype was built and tested to measure background events. A satisfactory unmanned field operation of the detector system was demonstrated. Besides, a detailed Monte Carlo simulation code was developed to estimate the antineutrino detection efficiency of the detector.Comment: 23 pages, 11 figures; accepted for publication in Nuclear Instruments and Methods in Physics Research

    Quantum-state input-output relations for absorbing cavities

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    The quantized electromagnetic field inside and outside an absorbing high-QQ cavity is studied, with special emphasis on the absorption losses in the coupling mirror and their influence on the outgoing field. Generalized operator input-output relations are derived, which are used to calculate the Wigner function of the outgoing field. To illustrate the theory, the preparation of the outgoing field in a Schr\"{o}dinger cat-like state is discussed.Comment: 12 pages, 5 eps figure

    Reflections from a Realist Evaluation in Progress: Scaling Ladders and Stitching Theory

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    Realist evaluation provides valuable insights into how and why programmes lead to change, and can generate transferable lessons to help practitioners roll out or scale up an intervention. However, as yet there are few standards and guidelines governing what counts as a ‘good’ realist evaluation. This CDI Practice Paper, written by Melanie Punton, Isabel Vogel and Rob Lloyd, reflects on the first year of a three-year realist impact evaluation, examining the Building Capacity to Use Research Evidence (BCURE) programme funded by the UK Department for International Development (DFID). It describes some of the challenges faced and lessons learned, providing insights into the potential value of realist approaches within international development.UK Department for International Developmen
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