109 research outputs found
Comparative Analysis of Surface Plants of the Ground Sealing Composition in the Implementation of Construction Works
Processes of layer-by-layer consolidation of soil at construction of the bulk engineering constructions built by method of continuous consolidation are considered. Ways of realization of these processes on the basis of two technological schemes - elliptic and shuttle are shown. The assessment of key parameters is made during the operation of units on the classical elliptic scheme of continuous consolidation of soil and on the elliptic scheme with use of a ring method of a turn of the unit when in the course of construction of a road bed automobile and the railroads the movement of the condensing unit is made from roadsides to an axis. It is shown that working platform* more effective andleast critical to topographical and geometrical parameters, the shuttle scheme of consolidation at which the condensing cars make the back and forth motions accompanied with lateral shift on an adjacent working strip after achievement of the demanded density on the previous strip is. The analsis of the major factors proving application of this or that technological scheme of soil consolidation is made. Operating conditions of units depending on type of the used condensing unit and the accepted production technology of works on elliptic and shuttle schemes which realization allows to reach the greatest production effect are studie
The motion of the 2D hydrodynamic Chaplygin sleigh in the presence of circulation
We consider the motion of a planar rigid body in a potential flow with
circulation and subject to a certain nonholonomic constraint. This model is
related to the design of underwater vehicles.
The equations of motion admit a reduction to a 2-dimensional nonlinear
system, which is integrated explicitly. We show that the reduced system
comprises both asymptotic and periodic dynamics separated by a critical value
of the energy, and give a complete classification of types of the motion. Then
we describe the whole variety of the trajectories of the body on the plane.Comment: 25 pages, 7 figures. This article uses some introductory material
from arXiv:1109.321
Vortex Polarity Switching in Magnets with Surface Anisotropy
Vortex core reversal in magnetic particle is essentially influenced by a
surface anisotropy. Under the action of a perpendicular static magnetic field
the vortex core undergoes a shape deformationof pillow- or barrel-shaped type,
depending on the type of the surface anisotropy. This deformation plays a key
point in the switching mechanism: We predict that the vortex polarity switching
is accompanied (i) by a linear singularity in case of Heisenberg magnet with
bulk anisotropy only and (ii) by a point singularities in case of surface
anisotropy or exchange anisotropy. We study in details the switching process
using spin-lattice simulations and propose a simple analytical description
using a wired core model, which provides an adequate description of the Bloch
point statics, its dynamics and the Bloch point mediated switching process. Our
analytical predictions are confirmed by spin-lattice simulations for Heisenberg
magnet and micromagnetic simulations for nanomagnet with account of a dipolar
interaction.Comment: 17 pages, 15 figure
The Study of Bacterial Leaching of Synthetic Valleriite-Containing Materials
Проведены поисковые эксперименты по бактериальному кондиционированию
синтетического валлериита в аэробных и анаэробных условиях. В ходе аэробного процесса
происходит окислительное выщелачивание валлериита с образованием соединений железа (+3)
и меди (+2). В анаэробных условиях поверхность валлериита, по данным рентгенофотоэлектронной
спектроскопии, частично окисляется, особенно за счет сульфидной серы, связанной с железом
(+3), но медь остается в степени окисления +1 в составе валлериита и частично сульфидов меди.
Установленные закономерности окисления валлериита необходимо учитывать при разработке
технологий обогащения и химико-металлургической
переработке валлериитсодержащих рудUnder aerobic and anaerobic conditions, a series of preliminary experiments on bacterial leaching of synthetic valleriites were performed. Under aerobic conditions, an oxidative leaching of iron (+3) and copper (+2) species was found. Under anaerobic conditions, surface of valleeriite was revealed by XPS analysis to oxidize, at least, partially, especially, due to sulfide sulfur. However, copper has kept its oxidative state (+1) in both initial material and, to some extent, in newly formed copper (+1) sulfide. The characteristics established in the present work are necessary to take into account when developing beneficiation technologies and hydrometallurgical processing of valleriite-bearing ore
Measurement of inclusive production in hadronic decays
An analysis is presented of inclusive \pi^0 production in Z^0 decays measured with the DELPHI detector. At low energies, \pi^0 decays are reconstructed by \linebreak using pairs of converted photons and combinations of converted photons and photons reconstructed in the barrel electromagnetic calorimeter (HPC). At high energies (up to x_p = 2 \cdot p_{\pi}/\sqrt{s} = 0.75) the excellent granularity of the HPC is exploited to search for two-photon substructures in single showers. The inclusive differential cross section is measured as a function of energy for {q\overline q} and {b \bar b} events. The number of \pi^0's per hadronic Z^0 event is N(\pi^0)/ Z_{had}^0 = 9.2 \pm 0.2 \mbox{(stat)} \pm 1.0 \mbox{(syst)} and for {b \bar b}~events the number of \pi^0's is {\mathrm N(\pi^0)/ b \overline b} = 10.1 \pm 0.4 \mbox{(stat)} \pm 1.1 \mbox{(syst)} . The ratio of the number of \pi^0's in b \overline b events to hadronic Z^0 events is less affected by the systematic errors and is found to be 1.09 \pm 0.05 \pm 0.01. The measured \pi^0 cross sections are compared with the predictions of different parton shower models. For hadronic events, the peak position in the \mathrm \xi_p = \ln(1/x_p) distribution is \xi_p^{\star} = 3.90^{+0.24}_{-0.14}. The average number of \pi^0's from the decay of primary \mathrm B hadrons is found to be {\mathrm N} (B \rightarrow \pi^0 \, X)/\mbox{B hadron} = 2.78 \pm 0.15 \mbox{(stat)} \pm 0.60 \mbox{(syst)}
Measurements of the leptonic branching fractions of the
Data collected with the DELPHI detector from 1993 to 1995 combined with previous DELPHI results for data from 1991 and 1992 yield the branching fractions B({\tau \rightarrow \mbox{\rm e} \nu \bar{\nu}}) = (17.877 \pm 0.109_{stat} \pm 0.110_{sys} )\% and
Search for new phenomena using single photon events in the DELPHI detector at LEP
Data are presented on the reaction \epem~\into~\gamma + no other detected particle at center-of-mass energies, \sqs = 89.48 GeV, 91.26 GeV and 93.08 GeV. The cross section for this reaction is related directly to the number of light neutrino generations which couple to the \zz boson, and to several other phenomena such as excited neutrinos, the production of an invisible `X' particle, a possible magnetic moment of the tau neutrino, and neutral monojets. Based on the observed number of single photon events, the number of light neutrinos which couple to the \zz is measured to be N_\nu = 3.15 \pm 0.34. No evidence is found for anomalous production of energetic single photons, and upper limits at the 95\% confidence level are determined for excited neutrino production (BR < 4-9 \times 10^{-6}), production of an invisible `X' particle (\sigma < 0.1 pb), and the magnetic moment of the tau neutrino (< 5.2 \times 10^{-6} \mu_B). No event with the topology of a neutral monojet is found, and this corresponds to the limit \sigma < 0.044/\epsilon pb at the 95\% confidence level, where \epsilon is the unknown overall monojet detection efficiency
Measurement of the B oscillation frequency using kaons, leptons and jet charge
A measurement of the mass difference, \Delta m_d, between the two physical \mbox{B}^0_d states has been obtained from the analysis of the impact parameter distribution of a lepton emitted at large transverse momentum (p_t) relative to the jet axis and from the analysis of the flight distance distribution of secondary vertices tagged by either a high p_t lepton or an identified kaon. In the opposite hemisphere of the event, the charge of the initial quark has been evaluated using a high p_t lepton, a charged kaon or the mean jet charge. With 1.7 million hadronic Z^0 decays recorded by DELPHI between 1991 and 1993, \Delta m_d is found to be: \Delta m_d = 0.531^{+0.050}_{-0.046} ~(stat.) \pm 0.078 ~(syst.) ~ {\mathrm{ps}}^{-1} \,
Measurement of the Quark and Gluon Fragmentation Functions in Hadronic Decays
The fragmentation functions and multiplicities in and light quark events are compared. The measured transverse and longitudinal components of the fragmentation function allow the gluon fragmentation function to be evaluated
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