4,631 research outputs found

    Process for making diamonds

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    A description is given of a device and process for making industrial diamonds. The device is composed of an exponential horn tapering from a large end to a small end, with a copper plate against the large end. A magnetic hammer abuts the copper plate. The copper plate and magnetic hammer function together to create a shock wave at the large end of the horn. As the wave propagates to the small end, the extreme pressure and temperature caused by the wave transforms the graphite, present in an anvil pocket at the small end, into diamonds

    Synthesis of diamonds

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    Shock wave transmitted through a solid exponential horn generates heat and pressure to convert part of a charge of graphite to diamonds. The shock wave is generated in the apparatus by a complex of magnetic fields and eddy currents

    Digital correlation of DDRS data

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    The reduction of digital SAR (synthetic aperture radar) data to radar images for use in remote sensing applications was investigated. The critical software operations are discussed in detail, and suggestions and recommendations are made for improving the algorithms currently being used

    Development of a ground signal processor for digital synthetic array radar data

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    A modified APQ-102 sidelooking array radar (SLAR) in a B-57 aircraft test bed is used, with other optical and infrared sensors, in remote sensing of Earth surface features for various users at NASA Johnson Space Center. The video from the radar is normally recorded on photographic film and subsequently processed photographically into high resolution radar images. Using a high speed sampling (digitizing) system, the two receiver channels of cross-and co-polarized video are recorded on wideband magnetic tape along with radar and platform parameters. These data are subsequently reformatted and processed into digital synthetic aperture radar images with the image data available on magnetic tape for subsequent analysis by investigators. The system design and results obtained are described

    APQ-102 imaging radar digital image quality study

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    A modified APQ-102 sidelooking radar collected synthetic aperture radar (SAR) data which was digitized and recorded on wideband magnetic tape. These tapes were then ground processed into computer compatible tapes (CCT's). The CCT's may then be processed into high resolution radar images by software on the CYBER computer

    Global Earth Response to Loading by Ocean Tide Models

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    Mathematical and programming techniques to numerically calculate Earth response to global semidiurnal and diurnal ocean tide models were developed. Global vertical crustal deformations were evaluated for M sub 2, S sub 2, N sub 2, K sub 2, K sub 1, O sub 1, and P sub 1 ocean tide loading, while horizontal deformations were evaluated for the M sub 2 tidal load. Tidal gravity calculations were performed for M sub 2 tidal loads, and strain tensor elements were evaluated for M sub 2 loads. The M sub 2 solution used for the ocean tide included the effects of self-gravitation and crustal loading

    Application of Thermal Storage, Peak Shaving and Cogeneration for Hospitals

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    Energy costs of hospitals can be managed by employing various strategies to control peak electrical demand (KW) while at the same time providing additional security of operation in the event that an equipment failure or a disruption of power from the electric utility occurs. Some electric utilities offer their customers demand (KW) reduction rate incentives. Many hospitals have additional emergency back-up needs for electrical energy. Demand is relatively constant in many hospitals due to high internal loads. These factors coupled with the present competitive alternate fuel market and present opportunities for hospitals to significantly reduce operating costs and provide additional stand-by or back-up electric sources. This paper employs a hospital case study to define and illustrate three energy planning strategies applicable to hospitals. These strategies are peak shaving, thermal storage, cogeneration and/or paralleling with the electric utility

    Gravitational instantons, self-duality and geometric flows

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    We discuss four-dimensional "spatially homogeneous" gravitational instantons. These are self-dual solutions of Euclidean vacuum Einstein's equations with potentially non-vanishing cosmological constant. They are endowed with a product structure R \times M_3 leading to a natural foliation into three-dimensional subspaces evolving in Euclidean time. For a large class of three-dimensional subspaces, the dynamics coincides with the geometric flow on the three-dimensional homogeneous slice, driven by the Ricci tensor plus an so(3) gauge connection. The metric on the three-dimensional space is related to the vielbein of the three-dimensional subspace, while the gauge field is inherited from the anti-self-dual component of the four-dimensional Levi--Civita connection.Comment: 14 page

    Exact Half-BPS Flux Solutions in M-theory with D(2,1;c′;0)2D(2, 1; c'; 0)^2 Symmetry: Local Solutions

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    We construct local solutions to 11-dimensional supergravity (or M-theory), which are invariant under the superalgebra D(2,1;c′;0)⊕D(2,1;c′;0)D(2, 1; c'; 0)\oplus D(2, 1; c'; 0) for all values of the parameter c′c'. The BPS constraints are reduced to a single linear PDE on a complex function GG. The PDE was solved in 0806.0605 modulo application of boundary and regularity conditions. The physical fields of the solutions are determined by c′c', a harmonic function hh, and the complex function GG. h h and GG are both functions on a 2-dimensional compact Riemannian manifold. The harmonic function h h is freely chosen. We obtain the expressions for the metric and the field strength in terms of GG, hh, and c′c' and show that these are indeed valid solutions of the Einstein, Maxwell, and Bianchi equations. Finally we give a construction of one parameter deformations of AdS7×S4AdS_7 \times S^4 and AdS4×S7AdS_4 \times S^7 as a function of c′c'

    Computer modeling of a wideswath SAR concept employing multiple antenna beam formation techniques

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    A technique for wideswath synthetic aperture radar coverage, was implemented into the OSS (orbital sar simulation) computer programs. The OSS modifications, and the implementation and simulation of the concept are described. The wideswath technique uses formed multiple antenna beams
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