Физические механизмы подъёма балластных гранул при прохождении высокоскоростных поездов

The article analyzes the mechanisms of crushed stone flying on high-speed railways. The objective of the work was to study and identify main mechanisms entailing flight of crushed stone from the ballast bed. It is substantiated that the main mechanism consists in squeezing of crushed stone particles from the upper layer of granules and their rise above the crushed stone bed following the action of longitudinal and transverse stresses in ballast, and that the most probable places of ejection of crushed stone particles is the border of contact between sleepers and the upper layer of the crushed stone bed.The physics of this process is presented, which consists in lifting ballast by turbulent vortices, suspension of crushed stone particles over the bed under the influence of vibration, in collision of moving particles and the process of squeezing and ejection of ballast granules. The reasons for the occurrence of horizontal and lateral stresses in crushed stone ballast are shown.В статье проанализированы механизмы вылета щебня при высокоскоростном движении. Целью работы является исследование и выявление основного механизма вылета щебня из балластной постели. Обосновано, что им является выдавливание частиц из верхнего слоя гранул и их подъём над щебёночной постелью в результате действия продольных и поперечных напряжений в балласте, а наиболее вероятным местом их вылета является граница контакта шпал и верхнего слоя щебёночной постели.Представлена физика этого процесса, состоящая в подъёме балласта турбулентными вихрями, «взвешивании» частиц щебня над постелью под действием вибрации, в соударении движущихся частиц и процессе выдавливания и вылета гранул балласта.Показаны причины возникновения горизонтальных и поперечных напряжений в щебёночном балласте

Remote photoplethysmography for the neuro-electrostimulation procedures monitoring the possibilities of remote photoplethysmography application for the analysis of high frequency parameters of heart rate variability

The paper presents assessments of the remote photoplethysmography (rPPG) capabilities for evaluation of heart rate variability (HRV) for monitoring the neuro-electrostimulation procedures. In our experiment, 20 minute long videos of 20 people in office lighting conditions were analyzed. We checked the accuracy of well-known methods and some modern methods of rPPG. In this work, we evaluated the accuracy of rPPG methods in high frequency (HF) band (0.4 - 0.15 Hz), and sub-bands (0.4 - 0.3 Hz), (0.3 - 0.15 Hz). For the sub-band (0.3-0.15 Hz) HRV signals obtained with rPPG are better correlated with HRV signals obtained with electrocardiography (ECG). The results have shown that POS method provides the best HRV parameter evaluation. Copyright © 2017 by SCITEPRESS – Science and Technology Publications, Lda. All rights reserved.The work was supported by Act 211 Government of the Russian Federation, contract 02.A03.21.0006. And partially supported by Russian Foundation for Assistance to Small Innovative Enterprises (FASIE) (Russia)

Modelling large-sized mesh reflector with extended aperture

Offset large-sized deployable mesh reflector with symmetric frontal and rear nets is described in the paper. This reflector involves extended aperture area and reduced framework elements by applying beam elements in the peripheral areas of reflecting surface. Strain-stress analysis is conducted to calculate reflecting surface shape of required accuracy

GEOCHRONOLOGY AND SR-ND ISOTOPE GEOCHEMISTRY OF LATE PALEOZOIC COLLISIONAL GRANITOIDS OF UNDINSKY COMPLEX (EASTERN TRANSBAIKAL REGION)

There are several geodynamic models of the Central Asian Orogenic Belt (CAOB) development [Şengör et al., 1993, Zorin, 1999; Parfenov et al., 1999, 2003; Willem et al., 2012; and others]. The Mongol-Okhotsk Orogenic Belt (MOB) represents important part of CAOB. All geodymanic models of Late Riphean to Paleozoic structures of CAOB emphasize significance of subduction processes along Northern Asian craton margin at that time. Collage of CAOB terrains formed as a result of accretion of island arc, accretionary wedge, turbidite, and continental margin terrains to the Siberian paleocontinent.There are several geodynamic models of the Central Asian Orogenic Belt (CAOB) development [Şengör et al., 1993, Zorin, 1999; Parfenov et al., 1999, 2003; Willem et al., 2012; and others]. The Mongol-Okhotsk Orogenic Belt (MOB) represents important part of CAOB. All geodymanic models of Late Riphean to Paleozoic structures of CAOB emphasize significance of subduction processes along Northern Asian craton margin at that time. Collage of CAOB terrains formed as a result of accretion of island arc, accretionary wedge, turbidite, and continental margin terrains to the Siberian paleocontinent

Stress-strain state simulation of large-sized cable-stayed shell structures

This paper studies the opportunities for applying framed cable-stayed shell structures to generate innovative structures in civil engineering. Numerical solution methods for stress-strain state problems of these kinds of geometrically nonlinear structures were developed. Developed methods efficiency is presented by a range of large-dimensional space antenna reflectors

Cyclotron Resonance Assisted Photocurrents in Surface States of a 3D Topological Insulator Based on a Strained High Mobility HgTe Film

We report on the observation of cyclotron resonance induced photocurrents, excited by continuous wave terahertz radiation, in a 3D topological insulator (TI) based on an 80 nm strained HgTe film. The analysis of the photocurrent formation is supported by complimentary measurements of magneto-transport and radiation transmission. We demonstrate that the photocurrent is generated in the topologically protected surface states. Studying the resonance response in a gated sample we examined the behavior of the photocurrent, which enables us to extract the mobility and the cyclotron mass as a function of the Fermi energy. For high gate voltages we also detected cyclotron resonance (CR) of bulk carriers, with a mass about two times larger than that obtained for the surface states. The origin of the CR assisted photocurrent is discussed in terms of asymmetric scattering of TI surface carriers in the momentum space. Furthermore, we show that studying the photocurrent in gated samples provides a sensitive method to probe the effective masses and the mobility of 2D Dirac surface states, when the Fermi level lies in the bulk energy gap or even in the conduction band

Breakdown of PCAC in diffractive neutrino interactions

We test the hypothesis of partially conserved axial current (PCAC) in high energy diffractive neutrino production of pions. Since the pion pole contribution to the Adler relation (AR) is forbidden by conservation of the lepton current, the heavier states, like the a_1 pole, \rho-\pi-cut, etc., control the lifetime of the hadronic fluctuations of the neutrino. We evaluate the deviation from the AR in diffractive neutrino-production of pions on proton and nuclear targets. At high energies, when all the relevant time scales considerably exceed the size of the target, the AR explicitly breaks down on an absorptive target, such as a heavy nucleus. In this regime, close to the black disc limit, the off-diagonal diffractive amplitudes vanish, while the diagonal one, \pi->\pi, which enters the AR, maximizes and saturates the unitarity bound. At lower energies, in the regime of short lifetime of heavy hadronic fluctuations the AR is restored, i.e. it is not altered by the nuclear effects.Comment: 10 pages, 5 figure