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The power required for an inclined screw conveyer with specified productivity is calculated, taking account of the hydraulic drag in the transportation of dry crushed material. The hydraulic drag of the crushed material is found to depend considerably on the conveyer's inclination. With increase in screw diameter, the hydraulic drag decreases. Therefore, the diameter must be increased when the packing density of the crushed material is high. [ABSTRACT FROM AUTHOR]

A system for the production of activated carbon is considered. The thermal deformation of its components in operation is of interest. A frame design is developed, taking account of the thermal deformation. The strength of the frame is calculated. [ABSTRACT FROM AUTHOR]

We present the leading-color two-loop QCD corrections for the scattering of four partons and a W boson, including its leptonic decay. The amplitudes are assembled from the planar two-loop helicity amplitudes for four partons and a vector boson decaying to a lepton pair, which are also used to determine the planar two-loop amplitudes for four partons and a Z/γ∗ boson with a leptonic decay. The analytic expressions are obtained by setting up a dedicated Ansatz and constraining the free parameters from numerical samples obtained within the framework of numerical unitarity. The large linear systems that must be solved to determine the analytic expressions are constructed to be in Vandermonde form. Such systems can be very efficiently solved, bypassing the bottleneck of Gaussian elimination. Our results are expressed in a basis of one-mass pentagon functions, which opens the possibility of their efficient numerical evaluation. [ABSTRACT FROM AUTHOR]

We present the complete set of leading-color two-loop contributions required to obtain next-to-next-to-leading-order (NNLO) QCD corrections to three-jet production at hadron colliders. We obtain analytic expressions for a generating set of finite remainders, valid in the physical region for three-jet production. The analytic continuation of the known Euclidean-region results is determined from a small set of numerical evaluations of the amplitudes. We obtain analytic expressions that are suitable for phenomenological applications and we present a C++ library for their efficient and stable numerical evaluation. [ABSTRACT FROM AUTHOR]

Mathematical models of the corrosion destruction of protective barriers of nuclear and radiation hazardous objects in the marine environment and the software tools developed for predicting the time of destruction and possible consequences of depressurization with pollution of the marine environment are analyzed. The models are based on the idea of an assemblage of protective barriers in the form of a directed weighted graph. Optimized algorithms taking into account the stochastic properties of corrosion made it possible to develop software tools in client-server architecture to estimate the time to complete destruction of protective barriers and the rate of release of radionuclides into the marine environment. [ABSTRACT FROM AUTHOR]

We compute the two-loop helicity amplitudes for the production of three photons at hadron colliders in QCD at leading-color. Using the two-loop numerical unitarity method coupled with analytic reconstruction techniques, we obtain the decomposition of the two-loop amplitudes in terms of master integrals in analytic form. These expressions are valid to all orders in the dimensional regulator. We use them to compute the two-loop finite remainders, which are given in a form that can be efficiently evaluated across the whole physical phase space. We further package these results in a public code which assembles the helicity-summed squared two-loop remainders, whose numerical stability across phase-space is demonstrated. This is the first time that a five-point two-loop process is publicly available for immediate phenomenological applications. [ABSTRACT FROM AUTHOR]

We complete the analytic calculation of the full set of two-loop Feynman integrals required for computation of massless five-particle scattering amplitudes. We employ the method of canonical differential equations to construct a minimal basis set of transcendental functions, pentagon functions, which is sufficient to express all planar and nonplanar massless five-point two-loop Feynman integrals in the whole physical phase space. We find analytic expressions for pentagon functions which are manifestly free of unphysical branch cuts. We present a public library for numerical evaluation of pentagon functions suitable for immediate phenomenological applications. [ABSTRACT FROM AUTHOR]

A mathematical model of corrosion damage to the protective barriers of radiation hazardous marine-based objects, taking account of the stochastic nature of this process, is constructed. The rate of pitting corrosion is determined by many mutually independent factors containing random components. This makes it possible to model pitting corrosion as a random walk process in which the corrosion rate changes discreetly and remains constant for one computational time step. The Monte Carlo method is used to calculate the depressurization time of an object with one protective barrier. The obtained estimates agree with expeditionary observations. [ABSTRACT FROM AUTHOR]

A method of calculating and the computational results obtained for the time variation of the radial deformation of the fuel-element cladding of a single-element EGC based on cermet with a polycrystalline molybdenum matrix in which uranium dioxide particles are distributed are presented. It is shown that the maximum admissible deformation of cladding comprised of 1-mm thick, hardened, single-crystalline, tungsten-tantalum alloy with a 10 mm in diameter central channel in the kernel is reached in 10 years. [ABSTRACT FROM AUTHOR]

The possible consequences of flooding of nuclear and radiation-hazardous sites and objects should be included among the environmental risks arising during the rapid development of the infrastructure in the Arctic. A mathematical model, algorithms, and software codes for evaluating the condition and predicting the collapse of the protective barriers, and determining the emission rate of radionuclides and the possible radioactive contamination of the environment, including long-term prediction and situation analysis, have been developed. The software codes have been accepted into the government registry at Rospatent. [ABSTRACT FROM AUTHOR]

A method of measuring the velocity of Hilbert-visualized phase structures by means of emulation of two-dimensional spatial filtering of their images formed on the matrix of a digital camcoder is discussed. As an example, visualized fields of the phase optical density in convective flows induced in a high-viscosity fluid are considered. Investigations of this kind of flows are useful for simulating the Earth's mantle behavior at large depths. [ABSTRACT FROM AUTHOR]

The cross sections for the spallation of the heavy-metal nuclei 181Ta, 197Au, 207Pb, 209Bi, 232Th, and 238U induced by relativistic deuterons with energies of 2, 2.94, and 3.5 GeV per nucleon are measured using the deuteron beam from the Nuclotron accelerator of the JINR Laboratory of High Energy Physics in Dubna, Russia. The cross-section measurements employ a combined experimental technique involving the solidstate nuclear-track detectors and the activation gamma spectrometry. Adding our measurements to the database of experimental nuclear data will make it possible to test the computer codes used for selecting the parameters of the ADS-type facilities. [ABSTRACT FROM AUTHOR]

Variants of a hypothetical accident that includes the occurrence of a spontaneous chain reaction are examined. The pathways and intensity of radionuclide emission from a nuclear submarine into seawater are determined. The Cs accumulation at the time of sinking is determined more accurately. The average and maximum Cs emission for use in predicting the contamination of the marine environment in application to the object under study are determined. [ABSTRACT FROM AUTHOR]

Cross-border propagation of Cs in the Barents Sea as result of a hypothetical accident associated with a self-maintained chain reaction in the reactors on the sunken nuclear submarine B-159 is predicted. The possible radioecological consequences of the radioactive contamination of the marine environments are evaluated. The results obtained are compared with approaches used abroad. [ABSTRACT FROM AUTHOR]

The methodology and results of a weighted average evaluation of the release of man-made radio-nuclides into seawater out of nuclear- and radiation-hazardous objects located on the sea bottom over a long period of time (from dumping/sinking to complete destruction of their structural elements) are presented in the paper. The expected radio-ecological implications of environmental contamination are estimated for the main stages of destruction. [ABSTRACT FROM AUTHOR]

We propose time-dependent Bell inequalities in a Wigner form, which expand the possibilities of experimental verification of Bohr's principle of complementarity in the relativistic domain and for nonstationary quantum-mechanical systems. Derivation of the proposed inequalities is based entirely on the Kolmogorov axiomatics of probability theory and the locality hypothesis. Violation of the obtained inequalities is considered in the framework of quantum theory based on the example of oscillations of neutral B mesons. [ABSTRACT FROM AUTHOR]

The article presents a method for calculating the mass transfer of uranium dioxide in high-temperature unvented fuel element. Topics discussed include transfer of uranium-containing components in the Central Channel of a Kernel in accordance with the kinetic theory of gases, experimental validation of the model and computational modelling. It also discusses the effect of filler gas on the process.

Methods of Hilbert filtration of phase disturbances of the light field in the spectral range of source emission are discussed. The evolution of complementary vortex rings induced in an air medium by a pressure pulse on the hole in the combustor wall under various boundary and initial conditions is experimentally studied. [ABSTRACT FROM AUTHOR]

The results of measurements of the beam parameters on the target upon irradiation of the QUINTA subcritical uranium assembly with deuterons with energies of 1, 4, and 8 GeV are presented. Data on the position of the incident particle beam relative to the assembly axis and on the actual geometric parameters of the beam make it possible to analyze information on the spatial distributions of reaction rates within the target assembly correctly, comparing such distributions obtained at different irradiation sessions and modeling the experiments with the use of MCNPX, GEANT4, FLUKA, and other similar software tools. [ABSTRACT FROM AUTHOR]

A classification of single-path current loops is proposed, on the basis of the spatial distribution of their magnetic field. The concept of point spherical loops is introduced, with the corresponding notation. The inductive action of a magnetic-field source on the loop is investigated. [ABSTRACT FROM AUTHOR]

The results of optimization calculations of a gas-removal apparatus in the form of a tube with a capillary tip are presented. Specifically, a criterion for choosing the length of a gas-removal tube for securing serviceability during a period of formation of an isothermal cavity in a uranium dioxide kernel is developed, the requirements for the geometric characteristics of a perforated protective screen are presented, and a mechanism for restoring the serviceability of the gas-removal system during a malfunction owing to mass transfer in irregular operating regimes of the EGC is described and substantiated. It is shown that uranium dioxide with sub-stoichiometric composition and single-crystal tungsten must be used for the gas-removal tube in order for the tube to be chemically stable and stable under thermal cycling. The results of reactor tests of an EGC are presented, and qualitatively confirm the computational results. [ABSTRACT FROM AUTHOR]

An optical method for measuring the geometric radius and velocity of slip of a wheel rolling on a rail is discussed. [ABSTRACT FROM AUTHOR]

The article investigates the impact of introducing heat-transmitting spacers in a uranium dioxide kernel on the deformation of high-temperature fuel elements. It outlines the heat-conduction equations employed in determining the temperature in the stationary case. A description of the stress-strain state of a fuel element is provided. It has found that introducing heart-transmitting spacers gives a negative result in terms of strain behavior of fuel elements.

A computational method and results for calculating the shape change of an initially spherical vacuum pore with migration in uranium dioxide fuel during operation of a high-temperature fuel element are presented. The conditions for a spherical fuel element to be elongated and flattened in the direction of the temperature gradient, i.e., its transformation into prolate and lenticular, are determined. It is shown that the sign of the second derivative of the saturated vapor pressure of uranium dioxide with respect to the radius of the fuel kernel is decisive. It is established that the region of formation of the prolate pores is located at the periphery of the cross section of a fuel kernel and that of lenticular pores at the center. As the thermal neutron fraction in the reactor spectrum increases, the formation region becomes narrower for prolate pores and wider for lenticular pores. [ABSTRACT FROM AUTHOR]

The problems of obtaining high reliability in the automated contactless monitoring of the geometric parameters of freight car wheels during the motion of a train under practical operating conditions using laser equipment are discussed. The factors which influence the reduction in the monitoring reliability are analyzed, and methods of reducing this influence (by a factor of 2–10) are demonstrated. An eddy-current sensor and a subsystem based on it for detecting defects in the rolling surface of wheel pairs are described. [ABSTRACT FROM AUTHOR]

Signal processing in the COMPLEX automated measurement system designed for noncontact inspection of wheel pairs of freight trains is described. The chosen coordinate base and methods of signal filtration and reconstruction ensure high reliability of measurement results during commercial operation even under conditions of intense atmospheric interferences. [ABSTRACT FROM AUTHOR]

Interaction of plasma flows with magnetic fields can lead to excitation of flute-like oscillations. These oscillations can also be excited in Z-pinch plasmas. We have developed understanding of nonlinear dynamics of compressible flute mode turbulence with spatial scales comparable to the ion Larmor radius in a high beta plasma, when these modes become electromagnetic and in the presence of a non-uniform magnetic field. It is shown that the flute waves are responsible for generation of large scale structures of streamer and zonal flow types as well as Kolmogorov type spectra in the short scale region. The relevance of the obtained results to laboratory astrophysics and Z-pinch experiments is discussed. [ABSTRACT FROM AUTHOR]

Dependences of the reflection coefficient of ions on their energy and the height and geometry of surface asperities obtained while studying ion beam interaction with targets by the Monte Carlo method have been analyzed. The dependences of the reflection coefficient on the height of asperities with a specified geometry under bombardment with ions of different energies, on the height of asperities for different angles of inclination of lateral walls at a specified energy of ions, and on the angle of inclination of walls for different ion energies at a fixed height have been considered. Generalized curves for reflection coefficients have been obtained, and analytical approximations have been calculated. [ABSTRACT FROM AUTHOR]

The evolution of the profile of a cone developing under ion bombardment on the etch pit bottom has been investigated by computer simulation taking into account sputtering and ion-induced migration of atoms. A twofold increase in the cone apex angle is observed, which is accompanied by the appearance of kinks on its generatrix. A plateau arises on the pit bottom and a circular parapet is formed above the flat surface. [ABSTRACT FROM AUTHOR]

The decay instability of a lser pulse propagating across an external magnetic field in a subscritical plasma is investigated analytically and numerically. It is shown that, when the relaxation of the pulse is taken into account, the hydrodynamic growth rate of the decay instability is slower than that obtained earlier in the constant-amplitude pump wave approximation. The results of numerical simulations by a particle-in-cell method demonstrate that an increase in the amplitude of the parametrically excited waves is accompanied by a decrease in their group velocity; in this case, up to 85% of the laser energy is converted into the energy of the plasma particles. It is found that, under resonance conditions, the magnetic field acts to increase the energy of the accelerated ions that escape from the plasma slab through its front boundary. [ABSTRACT FROM AUTHOR]

The problem of producing collisionless shocks in the laboratory is of great interest for space and astrophysical plasmas. One approach is based on the idea of combining strong magnetic field (up to 100 Tesla) created during a Z-pinch discharge with a plasma flow produced in the process of the interaction of a laser pulse with a solid target. In support of laboratory experiments we present hybrid simulations of the interaction of the plasma flow with frozen in it magnetic field, with the spherical obstacle. Parameters of the flow correspond to a laser plasma ablation produced in the laboratory during irradiation of the target by a 3 J laser. Magnetic fields in the plasma flow and around the obstacle are created by the currents produced by the pulse power ZEBRA voltage generator. With the appropriate set of initial conditions imposed on the flow collisionless shocks can be created in such a system. Using independent generators for plasma flow and magnetic field allows for the exploration of a wide range of shock parameters. We present simulations of the formation of supercritical collisionless shock relevant to the experiment, performed with the 2D version of the hybrid code based on the CAM-CL algorithm [Planet. Space Sci. 51, 649, 2003]. [ABSTRACT FROM AUTHOR]

An experimental simulation of planetary magnetospheres is being developed to investigate the formation of collisionless shocks and their effects. Two experimental situations are considered. In both, the solar wind is simulated by laser ablation plasmas. In one case, the “solar wind” flows across the magnetic field of a high-current discharge. In the other, a transverse magnetic field is embedded in the plasma flow, which interacts with a conductive obstacle. The ablation plasma is created using the “Tomcat” laser, currently emitting 5 J in a 6 ns pulse at 1 μm wavelength and irradiance above 1013 W/cm2. The “Zebra” z-pinch generator, with load current up to 1 MA and voltage up to 3.5 MV produces the magnetic fields. Hydrodynamic modeling is used to estimate the plasma parameters achievable at the front of the plasma flow and to optimize the experiment design. Particle-in-cell simulations reveal details of the interaction of the “solar wind” with an external magnetic field, including flow collimation and heating effects at the stopping point. Hybrid simulations show the formation of a bow shock at the interaction of a magnetized plasma flow with a conductor. The plasma density and the embedded field have characteristic spatial modulations in the shock region, with abrupt jumps and fine structure on the skin depth scale. [ABSTRACT FROM AUTHOR]

Process schemes for implementation of the optimum conditions of the final stage of orientational drawing of PP fibre are proposed based on the results of mathematical modeling. The existence of successive stages of transformation of the structure of PP fibre in the second stage of orientational drawing was experimentally confirmed with indirect indexes. The necessity of selecting the draw ratio that ensures completeness of the given stage of structural transformation is demonstrated. Structural schemes are proposed for automated control systems for selecting the optimum draw ratio in the first and final stages of orientational drawing and control of the structure of the spun polymer with indirect parameters. [ABSTRACT FROM AUTHOR]

The conditions are given for expansion of the magnetic fields of a source and a measuring winding into a main field and a scattering field. The salient features of the inductive effect of a source of magnetic field on a measuring winding are investigated on the basis of those conditions. [ABSTRACT FROM AUTHOR]

The stability of the properties of materials made of lanthanum chromite is determined primarily by their original porosity, and to a less degree by the content of free chromium oxide. An increase in the stability of the properties may be obtained by using a material with the minimum content of free chromium oxide, and the maximum possible density. The change in the porosity of the material on the basis of electrofused lanthanum chromite containing free chromium oxide, during use at high temperatures, is connected with the predominant removal of the chromium oxide and the completion of sintering of the material with volatilization of the CrO. The dynamics of the mass loss of lanthanum chromite depend not only on the nature of the volatilization (congruent or incongruent) but also on the material's porosity. [ABSTRACT FROM AUTHOR]

As a result of an investigation of sintering and the thermomechanical and physical properties of compact and granular ceramic of lanthanum chromite with 5% of added calcium oxide, fused in a cold container, the authors have selected a granular mass from which they prepared resistance heater elements capable of operating at surface temperatures of up to 1850°C. On the basis of such heaters they have designed, made, and operated a laboratory furnace with a working chamber temperature of up to 1750°C. [ABSTRACT FROM AUTHOR]

VLF quarter-gyrofrequency emissions, whose experimental characteristics differ from those of discrete plasmaspheric emissions usual during active times, have been observed by low-altitude Intercosmos 24 and Magion 2 satellites within the plasmasphere during periods of quieting geomagnetic activity. A new kind of instability is proposed which could lead to the production of these emissions. It is shown that quasi-electrostatic whistler waves can be generated in the eqquatorial region due to the fan instability, with maximum growth rate and spectral energy density in a frequency band below one half of the equatorial electron gyrofrequency. The observations of low-energy electrons and plasma waves in the equatorial region within or in the vicinity of the plasmapause, which could support our hypothesis experimentally, are discussed. [ABSTRACT FROM AUTHOR]

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Laboratory experiments on the interaction of a plasma flow, produced by laser ablation of a solid target with the inhomogeneous magnetic field from the Zebra pulsed power generator demonstrated the presence of strong wave activity in the region of the flow deceleration. The deceleration of the plasma flow can be interpreted as the appearance of a gravity-like force. The drift due to this force can lead to the excitation of flute modes. In this paper a linear dispersion equation for the excitation of electromagnetic flute-type modes with plasma and magnetic field parameters, corresponding to the ongoing experiments is examined. Results indicate that the wavelength of the excited flute modes strongly depends on the strength of the external magnetic field. For magnetic field strengths ∼0.1 MG the excited wavelengths are larger than the width of the laser ablated plasma plume and cannot be observed during the experiment. But for magnetic field strengths ∼1 MG the excited wavelengths are much smaller and can then be detected. [ABSTRACT FROM AUTHOR]