Vol 487, No 3 (2019)
- Year: 2019
- Articles: 23
- URL: https://journals.eco-vector.com/0869-5652/issue/view/805
- DOI: https://doi.org/10.31857/S0869-56524873
Mathematics
On the energy current for the harmonic crystals in the half-space
Abstract
We consider the dynamics of the harmonic crystal in the half-space with zero boundary condition. We assume that the initial data are a random function. We prove the convergence of the distributions of the solutions to a limiting measure for large times. The formula for the limiting energy current density (in mean) is derived. The application to the case of the Gibbs initial measures is given. We find the stationary non-equilibrium states, in which there exists a non-zero heat flow passing through the points of the crystal.
High excursions of Bessel process and other processes of Bessel type
Abstract
A high excursion probability for the modulus of a Gaussian vector process with independent identically distributed components is evaluated. It is assumed that the components have means zero and variances reaching its absolute maximum at a single point of the considered time interval. An important example of such processes is the Bessel process.
Mathematical physics
Many-dimensional tauberian theorems for holomorphic functions of bounded argument
Abstract
For generalized functions with Laplace transform has nonnegative imaginary part in tube domain over positive actant, we found sufficient conditions for existence of quasiasymptotic, the function with regular behavior with respect to which the quasiasymptotic exists being explicitly found. The obtained results are used to steady of the asymptotic behaviour of solutions of the Cauchy problem of passive operators.
Physics
Approximation of the n-vicinity method
Abstract
We determined a small parameter that determines the possibility of using the n-vicinity 06_method to calculate the free energy of a spin system, and found the types of spin systems for which this method is applicable. It is shown that this method is applicable for the analysis of spin systems, where the number of nearest neighbors is greater than 16/3.
Technical Physics
The influence of cavitation and the degree of overlap of the flow of cylindrical flow bodies on the flow pattern, hydrodynamic and spectral characteristics of a flat-type hydrodynamic generator
Abstract
The paper presents the results of studies of flow behind cylindrical flow bodies in a flat-flow hydrodynamic generator, obtained on the hydrodynamic bench of the experimental base of the National Scientific Center NBMT RAS with the degree of flow blocking by flow bodies St/S0 = 10-80%, Re numbers (0,5-5) · 105, PVH inlet pressure = 0,1-0,8 MPa. It was found that with the same pressure drop two different types of flow can be realized behind the flow bodies: with a developed cavitation zone, within which there is an extensive low pressure area and without it, but with the formation of vortex structures with the presence of centers of cavitation bubbles in them. At a certain value of input to output pressure, which is constant for each value of the degree of overlap of the flow, powerful pressure peaks of the resonant type arise with an amplitude of 2-2,5 times the maximum value of the input pressure. The frequency of occurrence of these pressure peaks increases linearly with increasing pressure drop, and decreases by an order of magnitude with an increase in the degree of overlap of flow up to 80%. The frequency dependence of the number Re for each value of St/S0 is linear. The value of the Strouhal number St with an increase in St/S0 increases linearly with St/S0 = 0,82 and the value St = 1,2.
Mechanics
Optimal disturbances of stably stratified turbulent Couette flow
Abstract
Direct numerical simulation data of a stably stratified turbulent Couette flow contains two types of organized structures: the rolls that arise at neutral and close to neutral stratification, and the layered structures, which manifest themselves as the static stability increases. It is shown that both types of structures have spatial scales and forms that coincide with the scales and forms of the corresponding optimal disturbances of the simplified linear model of the Couette flow with the same Richardson numbers.
Chemistry
Catalytic isomerization of substituted vinylcyclopropanes
Abstract
The catalytic isomerization of substituted vinyl-gem-dichlorocyclopropanes was studied in the presence of a series of zeolite catalysts. It is shown that the only reaction products are substituted gem-dichlorocyclopentenes. The influence of a number of factors (type of catalyst, temperature, reaction time) on the yield of isomerization products was investigated.
Chemical Technology
Mineral-polymer composites based on hydroxyapatite with polyvynylpyrrolidon for medicine
Abstract
Composites of hydroxyapatite (HA) with polyvinylpyrrolidone (PVP) were synthesized by precipitation in water solutions, mass relations of HA/PVP varied in region 3,6-14,5. The composite materials were investigated using XRD, IR, electron paramagnetic resonance (EPR) spectroscopy and transmission electron microscopy (TEM). Based on the TEM results it was found that during calcination of composites at 400 °C small agglomerates consisting of individual crystalline HA particles were formed, resulting in a particle size (according to TEM) slightly larger than coherent scattering region. Using the method of photoinduced EPR spectroscopy confirmed the presence of interaction between HA and PVP. The resulting composites can be used as materials for reconstructive surgery.
Physical chemistry
Inhibition of oxidated reducing reactions in the field of low frequency impacts
Abstract
The effect of low-frequency oscillations on a system consisting of two biochemically active components: the dye of methylene blue and ascorbic acid is investigated. Each of these components can be reversibly oxidized and reduced. The system is interesting in that it makes it possible to trace the influence of the low-frequency acoustic field on the mutual redox process and to reveal the features of the effect of such oscillations. It was found that, in this system, with the introduction of low-frequency effects, redox processes are not accelerated, but slowed down. There is an effect inhibition of the sound-chemical process in the field of low-frequency acoustic effects. The effect is quantified.
Geology
About morphology and genesis of washout-like structures in a coal seam at an object in the Eastern Donbas
Abstract
Based of study of the morphological features of a coal seam in a mine of the Eastern Donbas, the mineral and coal elements of the object studied were identified as a single sedimentary association of a pseudo-washout nature. Specific criteria for attributing coal-bearing structures to epigenetic or syngenetic washouts of a coal seam were elaborated.
Late stages in the evolution of the late Mesozoic East Mongolian volcanic areal: rock age and composition
Abstract
The Mandakh-Madal-Gobi (MMG) zone of alkali basalt magmatism has been delineated in the Late Mesozoic East Mongolian volcanic areal. It comprises clusters of igneous rock bodies and isolated stocks, domes, sills, laccoliths, dikes, and limited fragments of lava flows composed of tephrite, phono-tephrite, and trachybasalt. Two pulses of magmatism in the MMG zone have occurred in the Late Cretaceous (about 85 Ma) and Early Cenozoic (about 50 Ma). Recognition of this zone and deciphering of its formation history demonstrated that the development of the entire East Mongolian volcanic areal had the same regularities as those identified in other major regions of the Late Mesozoic Central Asia magmatic province. This indicates that the areal undoubtedly belongs to the latter. These facts support the conclusion that the correlation observed through the zone’s evolution between reduction in the volume of igneous products and the change in their composition towards the OIB was apparently determined by a decrease in the effect of thermal sublithospheric mantle melts upon a metasomatically enriched lithospheric mantle, leading to its gradual elimination from the magma sources.
Geochemistry
Hydrothermal synthesis of framed titanosilicates with a structure of ivanyukite mineral
Abstract
The phase formation in the Na2O-TiO2-SiO2-H2SO4-H2O system during hydrothermal has been studied. The obtained data were used for the producing of a new type of sorbents with a frame structure similar to the mineral ivanyukite. Excess amounts of silicon and sodium in relation to titanium (III) and titanium (IV) as well as pH up to 12 provide “supersaturating” of the salt mass and affect the rate of precipitation, phase composition, structure and surface properties. The framework arrangement of SiO4 tetrahedron and TiO6 octahedron create channels where Na+ and water molecules are located. The structure of ivanyukite along with mesoporosity provides its high ion-exchange properties.
Sources of eocene magmatism of Western Kamchatka (according to geochemical and isotope Sr-Nd-Pb characteristics of basites)
Abstract
The isotope-geochemical characteristics of the Eocene-Oligocene magmatic rocks of Western Kamchatka were studied. It is shown that the igneous rocks of the Eocene (45-53 Ma) Kinkil complex of Western Kamchatka are characterized by geochemical signs of super-subduction volcanism. Their isotopic composition of Sr, Nd and Pb, low concentrations of HFSE and HREE relative to the composition of MORB, suggest the formation of primary melts from depleted or poorly enriched in isotopic composition of the mantle wedge sources in different contaminated quartz-feldspath sialic sediments. From the end of the Middle Eocene on the territory of Western Kamchatka, K-Na alkaline-basalt magmatism (46-31 million years), whose geochemical characteristics are similar to E-MORB, as well as ultrapotassic alkaline-basalt magmatism, which continued to develop to the early Miocene (35-17 million years). The geodynamic nature of Late Paleogene alkaline magmatism involves the implementation of processes of diffuse rifting.
Geophysics
Variations of the parameters of internal gravity waves in the atmosphere of Central Asia before earthquakes
Abstract
Based on the data of experimental studies of wave disturbances in the Earth’s atmosphere before and after the earthquakes in Uzbekistan (May 26, 2013) and Kyrgyzstan (January 8, 2007), earlier unknown changes in the parameters of internal gravity waves are revealed. These changes were manifested during the period of five days before the earthquake and in certain cases can be used for short-term prediction of the time when seismic events are to occur.
Structure of the Khatanga-Lomonosov fracture zone according to seismic data
Abstract
According to the results of geophysical data interpretation considered the structural features of the Khatanga-Lomonosov fracture zones (HLZ), adapted to the strip joint part on the Laptev Sea continental margin with the structures of the spreading of the Eurasian basin and the Lomonosov ridge. Its reflection in anomalous geophysical fields, in a wave seismic picture on sections is shown on the example of separate links of HLZ and the character of its kinematic interrelations with heterogeneous tectonic elements is illustrated. The tectonic nature, role and place of this fault zone in the geodynamic evolution of the region are substantiated.
Geography
Estimation of the thermodynamic parameters of land cover from multispectral measurements of reflected solar radiation (Landsat) in terms of nonextensive statistical mechanics
Abstract
The use of the apparatus of nonadditive statistical mechanics for the evaluation of thermodynamic ecosystem variables based on multispectral measurements of reflected solar radiation is discussed. The parameter q is accepted corresponding to the conditions of the Förster’s maximum of organization. On the basis of remote information (Landsat) the entropy, Kullback information, Förster measure of organization, free energy, exergy, bound and internal energy, energy costs for evapotranspiration and photosynthesis for q-index values measured for each pixel of remote sensing scenes. It is shown that the seasonal dynamics of the q-index and the organization measures fully correspond to consequences that follow from the theory of open nonequilibrium systems, and thermodynamic variables reflect well the current state of ecosystems.
Results of cryotrasologic indication of paleosols encountered to the north of the European and West-Siberian Loess belt
Abstract
Rock freezing affects the soil complexes under maximal temperature gradients and forms a set of specific cryotrasological features in the solid soil matrix. When preserved these features serve as direct or indirect indicators of the past cryogenic conditions. Transformation of soil material on macro- and microscale belongs to the direct indicators whereas gleying in the well-drained positions, conditioned by the permafrost waterlogging is an indirect indicator. A variety of these features observed in the paleosols to the north of the European and West Siberian Loess belt was used by the authors to reconstruct the cryogenic environments of the late Pleistocene.
Oceanology
On deep-water reception of pseudorandom acoustical signals propagating from the shelf zone to the deep ocean
Abstract
The results of an experiment conducted in September 2017 to substantiate the applicability of the “acoustic mudslide” effect when solving the positioning problems of autonomous underwater vehicles in cases of their operation at depths substantially exceeding the depth of the axis of the underwater sound channel are discussed. The results of the experimental studies and numerical analysis of the effect of an acoustic energy focusing in the near-bottom layer of the shelf and its transition into deep-water (up to 500 m) layers of the Sea of Japan for summer-autumn hydrological conditions are presented. Mathematical modelling of the propagation of acoustic waves in a model waveguide reproducing the experimental conditions using the parabolic equation method has been performed. The observed effective signal propagation speeds are explained using the normal wave method.
Carbonate characteristics of the Gulf of Anadyr waters
Abstract
The first field data describing the dynamics of the carbonate system, aragonite saturation state, and CO2 fluxes between the ocean and the atmosphere in the Gulf of Anadyr in the late autumn season are presented. It was established that during this period the gulf waters absorbed carbon dioxide from the atmosphere at a rate of -22,5 mmol m‑2 day‑1, which determined the “classical” mechanism of seawater acidification due to uptake of excess atmospheric CO2. In general, surface waters of the gulf were supersaturated with respect to aragonite. The exception was the highly dynamic region of Anadyr Strait, where the vertical distribution of the investigated parameters was homogeneous, the surface waters were close to equilibrium with respect to aragonite, and CO2 flux was directed to the atmosphere. Bottom waters of the gulf, in contrast, were characterized by significant seasonal corrosivity with respect to aragonite due primarily to remineralization of organic matter to CO2. It was shown that during the late fall relatively salty and acidic, quasi-equilibrium with respect to aragonite, and oxygen-depleted waters with high concentrations of nutrients and CO2 have been entered the Chirkov Basin and further the Arctic Ocean with the Navarin current.
Biochemistry, biophysics, molecular biology
Effect of zinc excess and low temperature on the IRT1 gene expression in the roots and leaves of barley
Abstract
We studied the effect of zinc excess (1000 µM) and low temperature (4 °C) on the IRT1 gene expression in barley roots and leaves. Exposure at each of the stress factors separately, induced an increase in the content of the HvIRT1 gene transcripts, more pronounced in the leaves. At the same time, growth of seedlings continued. Under the combined action of factors in the first 3 days, the amount of mRNA also increased, but after 7 days of exposure it significantly declined, which corresponded with a complete inhibition of seedlings growth. It is assumed that the seedlings growth inhibition under the combined effect of the zinc excess and low temperature is associated with a decrease in the transcriptional activity of the HvIRT1 gene, due to the deficiency of a number of trace elements under these conditions.
Ethylene-insensitive Arabidopsis mutants etr1-1 AND ein2-1 have decreased freezing tolerance
Abstract
The freezing tolerance of Arabidopsis thaliana (L.) Heynh. was studied in relation to functioning of the ethylene signaling pathway. Constitutive freezing tolerance was compared in wild-type plants (ecotype Col-0) and ethylene-insensitive mutants etr1-1 and ein2-1. For the first time it was established that ethylene-insensitive mutants had by 25-30% lower net photosynthesis rate, the decreased content of soluble sugars and, as a result, lower freezing tolerance. Our work provides evidence that perception and transduction of ethylene signal are necessary for constitutive tolerance of Arabidopsis to low temperature.
General biology
Stimulation of seed germination by humic substances: on the nature of the phenomenon
Abstract
The effect of soil compared to sand on the germination of wheat seeds and the development of their seedlings, as well as the effect of seed treatment with humic substances on their development in sand and soils was studied. For a number of the Russian Plain soils, it was shown that the soils inhibit seed germination significantly. It was established that pre-sowing treatment of seeds with humic preparations has a noticeable stimulating effect when sowing treated seeds in sod-podzolic soil and has no effect practically when sowing these seeds in sand. On the basis of the known phenomenon of soil allelotoxicity, it was suggested that the stimulating effect of humic substances on seed development is to limit the influence of allelotoxins on their development.