4,024 research outputs found

    Complex research of acoustic impact on gas-dust flow in vortex-acoustic dispenser

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    Introduction The processing of wastes from mining operations is usually related to the needs of related industries in raw materials. The results of numerous studies on the complex processing of various man-made materials have confirmed the feasibility of their use to ensure resource-saving and obtain new types of products [1-3]. One of the most promising areas of industrial waste utilization is their integrated use in the production of building materials, which allows to meet the demand for raw materials up to 40% for this most important industry. The use of industrial waste allows to reduce costs for the manufacture of building materials 10-30% in comparison with their production from natural raw materials. The saving of capital investments makes 35-50% in this case [4-5]. In modern technology of building materials production, fine powders are one of the fundamental components that significantly affect the quality of finished products [6]. The fineness of material grinding is important for the intensification of various technological processes. However, the obtaining of a highly dispersed product is difficult due to increased energy consumption for material grinding, as well as their abrasiveness at an intensive abrasion, which causes a high wear of grinding bodies and other parts of a grinding unit. This leads to the increase of the grinding process cost, as well as to the obtaining of a poor-quality, contaminated product [7,8]. According to the data [9-10], the energy costs for the grinding of various materials reach 20% of the total energy consumption for production. The most promising method for fine and ultrafine grinding of various materials used in lowtonnage and innovative technologies is the jet method of grinding [11-12]

    Investigation of flows in boundary layers in processes of thin-layer separation

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    Analytical expressions have been obtained to determine lateral profiles of velocity distribution in boundary layers of separated phases, when monodisperse emulsions are separated. Equations, determining the thickness of boundary layers, have been formulated. The general picture of phase flows in the interplate clearances of the separator has been investigated. Thus, a simplified mathematical model has been developed to investigate the process of separating a monodisperse mixture in separators

    Criteria analysis of the equations of hydrodynamics for the processes of thin-layer separation

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    The general equations of motion of a monodisperse, two-phase medium in the zone of intertray spacing of a separator are analysed by the methods of similarity theory. Characteristic scales and similarity criteria are determined; the order of importance for the equation terms are estimated; the qualitative picture of the flow is established; and the simplified mathematical model of the processes of mixture separation are formulated in the boundary-layer approximation

    Mathematical model of the separation of polydisperse systems

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    A mathematical model is proposed for the thin-layer separation of a polydisperse mixture. The specific features of the process that are due to the variation of the concentration and composition of the dispersed phase along the interplate channel are considered

    OAS1 Polymorphisms Are Associated with Susceptibility to West Nile Encephalitis in Horses

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    West Nile virus, first identified within the United States in 1999, has since spread across the continental states and infected birds, humans and domestic animals, resulting in numerous deaths. Previous studies in mice identified the Oas1b gene, a member of the OAS/RNASEL innate immune system, as a determining factor for resistance to West Nile virus (WNV) infection. A recent case-control association study described mutations of human OAS1 associated with clinical susceptibility to WNV infection. Similar studies in horses, a particularly susceptible species, have been lacking, in part, because of the difficulty in collecting populations sufficiently homogenous in their infection and disease states. The equine OAS gene cluster most closely resembles the human cluster, with single copies of OAS1, OAS3 and OAS2 in the same orientation. With naturally occurring susceptible and resistant sub-populations to lethal West Nile encephalitis, we undertook a case-control association study to investigate whether, similar to humans (OAS1) and mice (Oas1b), equine OAS1 plays a role in resistance to severe WNV infection. We identified naturally occurring single nucleotide mutations in equine (Equus caballus) OAS1 and RNASEL genes and, using Fisher's Exact test, we provide evidence that mutations in equine OAS1 contribute to host susceptibility. Virtually all of the associated OAS1 polymorphisms were located within the interferon-inducible promoter, suggesting that differences in OAS1 gene expression may determine the host's ability to resist clinical manifestations associated with WNV infection

    Precise measurement of the W-boson mass with the CDF II detector

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    We have measured the W-boson mass MW using data corresponding to 2.2/fb of integrated luminosity collected in proton-antiproton collisions at 1.96 TeV with the CDF II detector at the Fermilab Tevatron collider. Samples consisting of 470126 W->enu candidates and 624708 W->munu candidates yield the measurement MW = 80387 +- 12 (stat) +- 15 (syst) = 80387 +- 19 MeV. This is the most precise measurement of the W-boson mass to date and significantly exceeds the precision of all previous measurements combined

    Combined search for the quarks of a sequential fourth generation

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    Results are presented from a search for a fourth generation of quarks produced singly or in pairs in a data set corresponding to an integrated luminosity of 5 inverse femtobarns recorded by the CMS experiment at the LHC in 2011. A novel strategy has been developed for a combined search for quarks of the up and down type in decay channels with at least one isolated muon or electron. Limits on the mass of the fourth-generation quarks and the relevant Cabibbo-Kobayashi-Maskawa matrix elements are derived in the context of a simple extension of the standard model with a sequential fourth generation of fermions. The existence of mass-degenerate fourth-generation quarks with masses below 685 GeV is excluded at 95% confidence level for minimal off-diagonal mixing between the third- and the fourth-generation quarks. With a mass difference of 25 GeV between the quark masses, the obtained limit on the masses of the fourth-generation quarks shifts by about +/- 20 GeV. These results significantly reduce the allowed parameter space for a fourth generation of fermions.Comment: Replaced with published version. Added journal reference and DO

    Measurement of the t t-bar production cross section in the dilepton channel in pp collisions at sqrt(s) = 7 TeV

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    The t t-bar production cross section (sigma[t t-bar]) is measured in proton-proton collisions at sqrt(s) = 7 TeV in data collected by the CMS experiment, corresponding to an integrated luminosity of 2.3 inverse femtobarns. The measurement is performed in events with two leptons (electrons or muons) in the final state, at least two jets identified as jets originating from b quarks, and the presence of an imbalance in transverse momentum. The measured value of sigma[t t-bar] for a top-quark mass of 172.5 GeV is 161.9 +/- 2.5 (stat.) +5.1/-5.0 (syst.) +/- 3.6(lumi.) pb, consistent with the prediction of the standard model.Comment: Replaced with published version. Included journal reference and DO

    Search for the standard model Higgs boson in the H to ZZ to 2l 2nu channel in pp collisions at sqrt(s) = 7 TeV

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    A search for the standard model Higgs boson in the H to ZZ to 2l 2nu decay channel, where l = e or mu, in pp collisions at a center-of-mass energy of 7 TeV is presented. The data were collected at the LHC, with the CMS detector, and correspond to an integrated luminosity of 4.6 inverse femtobarns. No significant excess is observed above the background expectation, and upper limits are set on the Higgs boson production cross section. The presence of the standard model Higgs boson with a mass in the 270-440 GeV range is excluded at 95% confidence level.Comment: Submitted to JHE
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