6,857 research outputs found

    Feasibility study of the grinding process of grain materials

    Get PDF
    For a comparative assessment of the effectiveness of various types of grinders of grain materials, various approaches are used. As the main criterion, the correspondence of the crushed material according to the particle size distribution can be taken as an indicator of the reliability of the grinding process. A comparative assessment of rotary crushers is carried out using the technical and economic indicator Eg, which is the ratio of total costs to the implementation of a given amount of work. Under the reliability of the grinding process, we have accepted the condition that the particle size distribution will comply with the requirements for agricultural feeding animals, which is possible while maintaining a rational gap between the stator and rotor riffles. The contradiction manufacturing techniques for the experiment are divided into: option No. 1 – steel 3 (HRC 10–12), option No. 2 – steel 45 (HRC 15–17), option No. 3 – hardened steel 45 (HRC 45–50), option No. 4 – steel 45 hardened and having a thin-film coating of FPH (finish plasma hardening), microhardness of 13 GPa. If reliability of the grinding process equal to 80%, wear on the fourth option, the cost was 1,171 rubles per ton, which is 16% lower than the cost of the first version of the production of a rotor crusher equal to 1,405 rubles per ton, respectively, this all speaks of the possible use of the proposed options for various forms of ownership of agricultural enterprises

    Comment on ``Damping of energetic gluons and quarks in high-temperature QCD''

    Full text link
    Burgess and Marini have recently pointed out that the leading contribution to the damping rate of energetic gluons and quarks in the QCD plasma, given by γ=cg2ln(1/g)T\gamma=c g^2\ln(1/g)T, can be obtained by simple arguments obviating the need of a fully resummed perturbation theory as developed by Braaten and Pisarski. Their calculation confirmed previous results of Braaten and Pisarski, but contradicted those proposed by Lebedev and Smilga. While agreeing with the general considerations made by Burgess and Marini, I correct their actual calculation of the damping rates, which is based on a wrong expression for the static limit of the resummed gluon propagator. The effect of this, however, turns out to be cancelled fortuitously by another mistake, so as to leave all of their conclusions unchanged. I also verify the gauge independence of the results, which in the corrected calculation arises in a less obvious manner.Comment: 5 page

    The value of extended amygdala structures in emotive effects of narcogenic with diverse chemical structure

    Get PDF
    To clarify the value of the extended amygdala structures (bed nucleus, central nucleus of the amygdala and nucleus accumbens shell) in the mechanisms of unconditioned and conditioned reinforcement activated by various narcogenic, this paper carried out a neuropharmacological analysis of these effects, using blockade of dopamine receptors, GABA, opioids and CRF receptors within these brain structures, as well as an analysis of behavioral responses by self-stimulation (unconditioned reinforcement) and conditioned place preference (CPP) (conditioned reinforcement

    Two-loop Compton and annihilation processes in thermal QCD

    Get PDF
    We calculate the Compton and annihilation production of a soft static lepton pair in a quark-gluon plasma in the two-loop approximation. We work in the context of the effective perturbative expansion based on the resummation of hard thermal loops. Double counting is avoided by subtracting appropriate counterterms. It is found that the two-loop diagrams give contributions of the same order as the one-loop diagram. Furthermore, these contributions are necessary to obtain agreement with the naive perturbative expansion in the limit of vanishing thermal masses.Comment: Latex, 24 pages, postscript figures included with the package graphic

    The electron thermal propagator at p>>T: An entire function of p_{0}

    Full text link
    The retarded electron propagator S_{R}(p_{0},p) at high momentum p>>T was shown by Blaizot and Iancu to be an entire function of complex p_{0}. In this paper a specific form for S_{R}(p_{0},p) is obtained and checked by showing that its temporal Fourier transform S_{R}(t, p) has the correct behavior at large t. Potential infrared and collinear divergences from the emission of soft photons do not occur.Comment: 8 page

    Molecular Density Functional Theory of Water describing Hydrophobicity at Short and Long Length Scales

    Full text link
    We present an extension of our recently introduced molecular density functional theory of water [G. Jeanmairet et al., J. Phys. Chem. Lett. 4, 619, 2013] to the solvation of hydrophobic solutes of various sizes, going from angstroms to nanometers. The theory is based on the quadratic expansion of the excess free energy in terms of two classical density fields, the particle density and the multipolar polarization density. Its implementation requires as input a molecular model of water and three measurable bulk properties, namely the structure factor and the k-dependent longitudinal and transverse dielectric susceptibilities. The fine three-dimensional water structure around small hydrophobic molecules is found to be well reproduced. In contrast the computed solvation free-energies appear overestimated and do not exhibit the correct qualitative behavior when the hydrophobic solute is grown in size. These shortcomings are corrected, in the spirit of the Lum-Chandler-Weeks theory, by complementing the functional with a truncated hard-sphere functional acting beyond quadratic order in density. It makes the resulting functional compatible with the Van-der-Waals theory of liquid-vapor coexistence at long range. Compared to available molecular simulations, the approach yields reasonable solvation structure and free energy of hard or soft spheres of increasing size, with a correct qualitative transition from a volume-driven to a surface-driven regime at the nanometer scale.Comment: 24 pages, 8 figure

    Dynamics of Two-Level System Interacting with Random Classical Field

    Full text link
    The dynamics of a particle interacting with random classical field in a two-well potential is studied by the functional integration method. The probability of particle localization in either of the wells is studied in detail. Certain field-averaged correlation functions for quantum-mechanical probabilities and the distribution function for the probabilities of final states (which can be considered as random variables in the presence of a random field) are calculated. The calculated correlators are used to discuss the dependence of the final state on the initial state. One of the main results of this work is that, although the off-diagonal elements of density matrix disappear with time, a particle in the system is localized incompletely (wave-packet reduction does not occur), and the distribution function for the probability of finding particle in one of the wells is a constant at infinite time.Comment: 5 page

    ALTICORE: an initiative for coastal altimetry

    No full text
    ALTICORE (value-added ALTImetry for COastal REgions) is an international initiative whose main objective is to encourage the operational use of altimetry over coastal areas, by improving the quality and availability of coastal altimetry data. The ALTICORE proposal has recently been submitted for funding to the INTAS scheme (www.intas.be) by a consortium of partners from Italy, France, UK, Russia and Azerbaijan. ALTICORE is also meant as a contribution to the ongoing International Altimeter Service effort. In this work we will describe the anticipated project stages, namely: 1) improvement of the most widely distributed, 1 Hz, data by analyzing the corrective terms and providing the best solutions, including those derived from appropriate local modelling; 2) development of a set of algorithms to automate quality control and gap-filling functions for the coastal regions; 3) development of testing strategies to ensure a thorough validation of the data. The improved products will be delivered to ALTICORE users via Grid-compliant technology; this makes it easier to integrate the local data holdings, allows access from a range of services, e.g. directly into model assimilation or GIS systems and should therefore facilitate a widespread and complete assessment of the 1Hz data performance and limitations. We will also outline the design and implementation of the Grid-compliant system for efficient access to distributed archives of data; this consists of regional data centres, each having primary responsibility for regional archives, local corrections and quality control, and operating a set of web-services allowing access to the full functionality of data extraction. We will conclude by discussing a follow-on phase of the project; this will investigate further improvements on the processing strategy, including the use of higher frequency (10 or 20 Hz) data. Phenomena happen at smaller spatial scales near the coast, so this approach is necessary to match the required resolution. The whole project will hopefully promote the 15-year sea surface height from altimetry to the rank of operational record for the coastal areas

    Normal and Anomalous Scaling of the Fourth-Order Correlation Function of a Randomly Advected Passive Scalar

    Full text link
    For a delta-correlated velocity field, simultaneous correlation functions of a passive scalar satisfy closed equations. We analyze the equation for the four-point function. To describe a solution completely, one has to solve the matching problems at the scale of the source and at the diffusion scale. We solve both the matching problems and thus find the dependence of the four-point correlation function on the diffusion and pumping scale for large space dimensionality dd. It is shown that anomalous scaling appears in the first order of 1/d1/d perturbation theory. Anomalous dimensions are found analytically both for the scalar field and for it's derivatives, in particular, for the dissipation field.Comment: 19 pages, RevTex 3.0, Submitted to Phys.Rev. E, revised versio
    corecore