36,132 research outputs found

    Prospects for Higgs Search at D0

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    The status of the Higgs search at the upgraded D0 detector is discussed.Comment: Proceedings submitted for PASCOS03, Mumbai, India, Jan 3-8, 200

    Measurements of the Top Quark Mass at D0

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    We present measurements of the top quark mass based on 3.6 fb^-1 of data collected by the D0 experiment during Run II of the Fermilab Tevatron collider. We present results in the dilepton and lepton+jets final states. We also present the measurement of the mass difference between t and tbar quarks observed in lepton+jets final states of ttbar events in 1 fb^-1 of data.Comment: Proceedings of the 17th International Conference on Supersymmetry and the Unification of Fundamental Interactions (SUSY09

    Space processing on Skylab and ASTP

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    The Skylab and Apollo Soyuz Test Project (ASTP) missions provided the opportunity the influence of micro-gravity on the processing of various materials. The results of physical and engineering experiments in metallurgy, fluids handling and crystal growth on two space missions are discussed. The majority of the experiments concern the solidification of alloys, semiconductors, and composite materials or basic liquid-liquid and solid-liquid interactions necessary to understand complex processing. Potential advantages of space processing to several materials disciplines are identified

    Lime Needs and Trends in Arkansas

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    Consumption of agricultural lime in Arkansas declined significantly during the past seven years. During each of the past four years, lime consumption was lower than any time since 1960. The quantity of lime needed for optimum crop production on Arkansas\u27 soils is estimated to be 2,678,700 metric tons (MT) (3,000,000 tons), based on University of Arkansas soil testing summaries. Since 1980, less than 285,728 MT(320,000 tons) of lime have been used each year. It is the natural tendency for most soils in Arkansas to become more acidic with time. Periodic addition of agricultural limestone, however, can neutralize soil acidity and help to maintain soil productivity. Nitrogen fertilizers, applied for the production of most agricultural crops, may also contribute to the acidification of soils. The annual consumption of acid-forming nitrogen fertilizers in Arkansas increased from approximately 223,225 MT(250,000 tons) during fiscal year 1974-75 to about 392,876 MT(440,000 tons) by fiscal year 1983-84. At least 2.5 times more lime was needed than was used, just to neutralize the residual acidity from acid-forming nitrogen fertilizers alone, during the same period. Shifts in crop hectareages did not account for the magnitude of decline observed in lime consumption. If lime consumption does not increase in the future, and if acid-forming nitrogen fertilizer consumption follows the current increasing trend, soil acidity will cause a decline in the yields of acid-sensitive crops

    Electrophoresis device

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    A device for separating cellular particles of a sample substance into fractionated streams of different cellular species includes a casing having a distribution chamber, a separation chamber, and a collection chamber. The electrode chambers are separated from the separation chamber interior by means of passages such that flow variations and membrane variations around the slotted portion of the electrode chamber do not enduce flow perturbations into the laminar buffer curtain flowing in the separation chamber. The cellular particles of the sample are separated under the influence of the electrical field and the separation chamber into streams of different cellular species. The streams of separated cells enter a partition array in the collection chamber where they are fractionated and collected

    Moving wall, continuous flow electronphoresis apparatus

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    This invention relates generally to electrophoresis devices and more particularly to a moving wall, continuous flow device in which an electrophoresis chamber is angularly positionable with respect to the direction of moving belt walls. A frame with an electrophoresis chamber is rotatably supported between two synchronously driven belt walls. This allows the chamber to be angularly positionable with respect to the direction of belt travel, which compensates for electroosmotic flow within the electrophoresis chamber. Injection of a buffer solution via an opening and a homogenous sample stream via another opening is performed at the end of a chamber, and collection of buffer and the fractionated species particles is done by a conventional collection array at an opposite end of the chamber. Belts are driven at a rate which exactly matches the flow of buffer and sample through the chamber, which entrains the buffer to behave as a rigid electrophoretic medium, eliminating flow distortions (Poiseuille effect). Additionally, belt material for each belt is stored at one end of the device and is taken up by drive wheels at an opposite end. The novelty of this invention particularly lies in the electrophoresis chamber being angularly positionable between two moving belt walls in order to compensate for electroosmotic flow. Additionally, new belt material is continuously exposed within the chamber, minimizing flow distortion due to contamination of the belt material by the sample

    Method of crystallization

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    A method is described for refining or growing bulk single crystals in an environment substantially free of gravity. The base material is suspended, positioned, and shaped as a containerless melt by wetting forces. Because no crucible is required, high temperature refractory materials can be processed

    Phonon engineering through crystal chemistry

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    Mitigation of the global energy crisis requires tailoring the thermal conductivity of materials. Low thermal conductivity is critical in a broad range of energy conversion technologies, including thermoelectrics and thermal barrier coatings. Here, we review the chemical trends and explore the origins of low thermal conductivity in crystalline materials. A unifying feature in the latest materials is the incorporation of structural complexity to decrease the phonon velocity and increase scattering. With this understanding, strategies for combining these mechanisms can be formulated for designing new materials with exceptionally low thermal conductivity

    Preparative electrophoresis for space

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    A premise of continuous flow electrophoresis is that removal of buoyance-induced thermal convection caused by axial and lateral temperature gradients results in ideal performance of these instruments in space. Although these gravity dependent phenomena disturb the rectilinear flow in the separation chamber when high voltage gradients or thick chamber are used, distortion of the injected sample stream due to electrodynamic effects cause major broadening of the separated bands. The electrophoresis separation process is simple, however flow local to the sample filament produced by the applied electric field were not considered. These electrohydrodynamic flows distort the sample stream and limit the separation. Also, electroosmosis and viscous flow combine to further distort the process. A moving wall concept is being proposed for space which will eliminate and control the disturbances. The moving wall entrains the fluid to move as a rigid body and produces a constant residence time for all samples distributed across the chamber thickness. The moving wall electrophoresis chamber can only be operated in space because there is no viscous flow in the chamber to stabilize against thermal convection
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