1,452,688 research outputs found

    NASA-tricot - A lightweight radar reflective, knitted fabric

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    Fabric knitted on conventional knitting machines uses commercially available yarns, has high aerodynamic drag capability, and is relatively inexpensive. The two yarn components used are 15-denier nylon monofilament and aluminized Mylar tape

    Low-cost, portable fire hose tester

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    Availability of pumping unit permits scheduling and performing required periodic hose tests in proper manner while retaining full fire equipment readiness. Use of pumping unit preserves operating life and capability of pumper truck

    High harmonic generation in crystals using Maximally Localized Wannier functions

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    In this work, the nonlinear optical response, and in particular, the high harmonic generation of semiconductors is addressed by using the Wannier gauge. One of the main problems in the time evolution of the Semiconductor Bloch equations resides in the fact that the dipole couplings between different bands can diverge and have a random phase along the reciprocal space and this leads to numerical instability. To address this problem, we propose the use of the Maximally Localized Wannier functions that provide a framework to map ab-initio calculations to an effective tight-binding Hamiltonian with great accuracy. We show that working in the Wannier gauge, the basis set in which the Bloch functions are constructed directly from the Wannier functions, the dipole couplings become smooth along the reciprocal space thus avoiding the problem of random phases. High harmonic generation spectrum is computed for a 2D monolayer of hBN as a numerical demonstration

    Investigation of rock behavior and strength in situ and laboratory techniques adaptability to a lunar exploration program

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    Rock testing techniques for lunar landing site and for lunar samples returned to earth laborator

    Interactions and superconductivity in heavily doped MoS2

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    We analyze the microscopic origin and the physical properties of the superconducting phase recently observed in MoS2_2. We show how the combination of the valley structure of the conduction band, the density dependence of the screening of the long range Coulomb interactions, the short range electronic repulsion, and the relative weakness of the electron-phonon interactions, makes possible the existence of a phase where the superconducting order parameter has opposite signs in different valleys, resembling the superconductivity found in the pnictides and cuprates

    Study of hot wire techniques in low density flows with high turbulence levels

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    Prediction of heat, mass, species, and momentum fluxes in a space vehicle and aerodynamic noise production by supersonic jet and rocket exhausts requires a predictability of the associated turbulence fields. The hot wire is a technique that will allow an experimental determination of turbulent properties

    Modification of the one-dimensional REKAP program to allow for charring in three material layers Final report

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    Modified one-dimensional reaction kinetics program to allow for charring in three material layers of rocket nozzle throat insert cas
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