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Technological schemes of delayed coking plants currently operated in oil refineries are compared. It is shown that the new-generation Russian technology is superior to licensed technologies of foreign firms in operational reliability, efficiency, and potentiality of producing various types of coke. [ABSTRACT FROM AUTHOR]

The possibility of proficient use of heavy oil residues and oil refining wastes as carbon additives in coal charges for metallurgical coke production is investigated. Involvement of petroleum coke fines and coking additives in coal charges makes it possible to significantly improve the performance properties of blast furnace coke. The available and prospective caking additive production technologies using heavy oil residues are studied and compared. [ABSTRACT FROM AUTHOR]

The production of a highly anisotropic structure of needle cokes depends not only on the quality of the feedstock but also on the hydrodynamic situation in the coke chamber formed as a result of shear stresses in the mesophase matrix by flows of released vapor-gas products of the coking distillate and continuous delivery of the raw materials. This paper presents the results of investigations on the quality of needle cokes produced during coking under static and dynamic conditions. It was shown that the microstructural organization of cokes can differ quite significantly depending on the coking technology. [ABSTRACT FROM AUTHOR]

Delayed carbonization is one of the most dynamically developing technologies in global petroleum processing. The basic factors determining the material balance and the quality of carbonization products are process parameters and quality of the feedstock used. However, data on the dependence of yield of gaseous and liquid carbonization products on the quality of the feedstock are absent in the domestic literature. This paper presents the developed mathematical models of the yield of heavy oil residue carbonization products, which help control products yield by varying the proportions of the components in the feedstock, taking account of the change in carbonizability of each component of the feedstock. [ABSTRACT FROM AUTHOR]

In dense multiple scattering media, optical fields evolve through both homogeneous and evanescent waves. New regimes of light transport emerge because of the near-field coupling between individual scattering centers at mesoscopic scales. We present a novel propagation model that is developed in terms of measurable far- and near-field scattering cross sections. Our quantitative description explains the increase of total transmission in dense scattering media and its accuracy is established through both full-scale numerical calculations and enhanced backscattering experiments. [ABSTRACT FROM AUTHOR]

Based on the conservation of linear momentum on scattering from arbitrary objects, we demonstrate the generation of nonconservative optical forces that act in a direction opposite to the propagation of the incident beam. The concept can be applied to tailor the force fields produced on nonabsorbing bodies regardless of their sizes and shapes. [ABSTRACT FROM AUTHOR]

The structure of glasses of the compositions xEr2O3-2 xTiO2-(100-3 x )TeO2 was investigated and the glass formation region, situated in the range of 2 < x < 7 was established. The possibility of increasing the glass transition temperature and consequently the thermal stability of erbium tellurite glass by doping with titanium (IV) oxide was demonstrated. [ABSTRACT FROM AUTHOR]

Transparent glass composites containing nonlinear optical (NLO) and luminescent crystals are of significant interest for the optical materials science in spire of a lot of difficulties to synthesize high-quality NLO composites: refractive index and density matching! of glass matrix and crystal, controlled chemical interaction between them, absence of crystal aggregation, cords, bubbles, etc. Low density and refractive index, high second harmonic generation (SHG) activity, rather a high melting point allow to refer KNbSi2O7 ferroelectric to a promising candidate for using in the NLO glass composite technology. Manifestation of NLO properties of crystals in glass composites is established to depend drastically on glass matrix composition. During re-melting lead containing glasses react chemically with KNbSi2O7 forming pyrochlore Pb2Nb2O7 which is dissolved gradually up to nano-scaled state exhibiting moderate SHG efficiency by analogy with nanostructured glasses because of space modulation of polarizability originated from nano-sized inhomogeneities enriched with Pb and Nb. Using of TeO2-based glasses permits to match reft active indexes of glass matrix and crystal, reduce glass melting temperature and fabricate transparent composites containing micron and sub-micron crystals with high second harmonic generation activity. [ABSTRACT FROM AUTHOR]

The optical response of a diatomic system excited by monochromatic light is studied. On the basis of a semiclassical approach, the effects of rearrangement of the energy spectrum of the system due to the dipole-dipole interaction and the effects related to variations in the orientation of the atomic dipole moments under the action of microscopic fields are jointly taken into account. The strongest response of the system is shown to occur at dimensional resonance frequencies. The number of observed intensity peaks depends on the position of the observation point with respect to the interatomic axis. The frequencies of the dimensional resonances are compared with other characteristic frequencies of the atomic spectrum. [ABSTRACT FROM AUTHOR]

The problem of classical optics related to the electromagnetic-field distribution near the surface of a dielectric medium with allowance made for its discrete structure is solved. The effect of a probe on the nearfield optical observations is taken into account, and the condition is obtained under which this effect can be neglected. It is shown that the near-field observations can be used to get information not only on the surface structure but also on the effective fields in the near-surface region. A method for optically controlling the probe position over the surface is proposed. [ABSTRACT FROM AUTHOR]

The microscopic theory of a transitional layer on the ideal surface of a semi-infinite absorbing or nonabsorbing isotropic dielectric is developed within the framework of classical optics when the polarization vector of the medium is a linear function of the electric field strength inside the medium. The concentration of atoms (molecules) of the medium and their polarizability are independent of coordinates and are constant inside the medium and close to its surface. The consideration is carried out within the framework of the concept of a discrete-continuous dielectric, in which the fields of dipoles of discretely distributed atoms (molecules) inside the Lorentz sphere surrounding the observation point are taken into account. The near-field effect is shown to result in a nonexponential behavior of the field nearby the surface. The thickness of the transitional layer can be found from experimental values of the reflected wave amplitude. [ABSTRACT FROM AUTHOR]

A boundary problem of linear classical optics is solved in which the behavior of the electromagnetic field near the surface of a dielectric medium is studied. It is shown that including the discrete structure of a medium into the analysis has the most substantial effect on the behavior of the electromagnetic field at distances smaller than 2a[sub 0], where a[sub 0] is the lattice constant. This fact makes it possible to obtain numerical estimates of the size of the region where the reflected and transmitted waves are formed. [ABSTRACT FROM AUTHOR]

Artificial neural networks (ANNs) experience catastrophic forgetting (CF) during sequential learning. In contrast, the brain can learn continuously without any signs of catastrophic forgetting. Spiking neural networks (SNNs) are the next generation of ANNs with many features borrowed from biological neural networks. Thus, SNNs potentially promise better resilience to CF. In this paper, we study the susceptibility of SNNs to CF and test several biologically inspired methods for mitigating catastrophic forgetting. SNNs are trained with biologically plausible local training rules based on spike-timing-dependent plasticity (STDP). Local training prohibits the direct use of CF prevention methods based on gradients of a global loss function. We developed and tested the method to determine the importance of synapses (weights) based on stochastic Langevin dynamics without the need for the gradients. Several other methods of catastrophic forgetting prevention adapted from analog neural networks were tested as well. The experiments were performed on freely available datasets in the SpykeTorch environment. • Coding information in spikes does not prevent catastrophic forgetting during continuous learning. • Pseudo-rehearsal with random samples provoke fast unlearning of previous knowledge in convolutional spiking neural networks. • Saving a small number of samples from previous datasets can effectively decrease catastrophic forgetting. • A stochastic process of weights diffusion can establish the importance of the weights in spiking networks trained with local rules. [ABSTRACT FROM AUTHOR]

The paper presents data on the abundance of bobak marmot (Marmota bobak Müller, 1776), obtained from 1987 till 2019. All censuses were performed according to one technique developed by us in the late 1980s. During these long-term investigations, the structure of the bobak marmot areal in the Saratov region was studied. The dynamics of its numbers is described, and its trends for individual groups of districts were revealed, distinguished by trends, the time of the appearance of new settlements as a result of reintroduction after a prolonged depression in the numbers caused by both plowing of the steppes and the well-known events of the 1920s, 1930s and 1940s, when the bobak marmot provided the survival of some part of the population. It has been established that the population peak in the indigenous settlements that have been existing from the end of the Pleistocene–the beginning of the Holocene, was in 1980–1990. New settlements arise in the territories where the marmot was reintroduced, and the species abundance continues to grow. This, first of all, refers to the western slopes of the Volga Upland and the Oka-Don plain, formerly inhabited by marmots. An increase in the numbers of the Kazakhstan subspecies of the bobak is observed at the eastern end of the Syrt plain and on the spurs of the Common Syrt in the Saratov Trans-Volga region. The genetic studies of steppe marmots by R.V. Naumov (2019) on the right Volga bank of the Ulyanovsk region showed that a genetically homogeneous population lives on the vast territory of the Volga region. This casts doubt on the assumption of the existence of the Kozlovi subspecies of the bobak marmot in the local territories of the Voskresensk, Volsk and Khvalynsk districts of the Saratov region, which served as the ground for its inclusion into the new edition of the Red Data Book of the region, which we consider unreasonable (Resolution..., 2019). [ABSTRACT FROM AUTHOR]

The structural morphology of complex dielectric media determines their functionalities by driving the statistical properties of the electromagnetic fields. Our controlled experiments and full electromagnetic calculations that go beyond common dipolar approximations demonstrate that the specific characteristics of disorder lead to non-Rayleigh statistics of detected intensity, which can be directly accessed in the near field of random media and can be unambiguously related to the short-range correlations of disorder. [ABSTRACT FROM AUTHOR]

The trigger for biomineralization of metazoans in the terminal Ediacaran, ca. 550 Ma, has been suggested to be the rise of oxygenation or an increase in seawater Ca concentration, but geochemical and fossil data have not been fully integrated to demonstrate cause and effect. Here we combine the record of macrofossils with early marine carbonate cement distribution within a relative depth framework for terminal Ediacaran to Cambrian successions on the eastern Siberian Platform, Russia, to interrogate the evolution of seawater chemistry and biotic response. Prior to ca. 545 Ma, the presence of early marine ferroan dolomite cement suggests dominantly ferruginous anoxic "aragonite-dolomite seas", with a very shallow oxic chemocline that supported mainly soft-bodied macrobiota. After ca. 545 Ma, marine cements changed to aragonite and/or high-Mg calcite, and this coincides with the appearance of widespread aragonite and high-Mg calcite skeletal metazoans, suggesting a profound change in seawater chemistry to "aragonite seas" with a deeper chemocline. By early Cambrian Stage 3, the first marine low-Mg calcite cements appear, coincident with the first low-Mg calcite metazoan skeletons, suggesting a further shift to "calcite seas". We suggest that this evolution of seawater chemistry was caused by enhanced continental denudation that increased the input of Ca into oceans so progressively lowering Mg/Ca, which, combined with more widespread oxic conditions, facilitated the rise of skeletal animals and in turn influenced the evolution of skeletal mineralogy. [ABSTRACT FROM AUTHOR]

Abstract—The present paper is devoted to the study of the possibility of estimating the reproductive potentials of wild ungulate populations and, possibly, other large mammals, on the basis of the time series of their numbers. We have found out that this is possible, which is confirmed by the high quality of approximation of the time series of abundance by logistic curves and the corresponding coefficients of their determination for different species ranging from 75 to 96%. For such calculations, one circumstance is necessary—that the population of the studied species has been briefly exposed to some unfavorable factor causing a significant reduction in its numbers with subsequent restoration to the previous level, or that the time series contains a well-expressed and extended section of the transition of the population from some lower level to the upper level of the population, passing into a stationary state. The values of the maximum exponential growth rates of ungulate populations that we obtained do not fundamentally differ from the data available in other researchers' works. In addition, it should be borne in mind that our method for assessing the reproductive potentials of ungulates is statistical, with features accompanying all such methods, for example, the presence of statistical errors in all determined parameters. However, the evaluation of the magnitude of these errors is a topic for a separate study. [ABSTRACT FROM AUTHOR]

The first nonlinear optic nanocomposite based on a low-melting vitreous matrix and a ferrielectric crystal has been obtained. The matrix consists of lead-borate glass and the filler is single-phase powder of ferrielectric KNbSi2O7. The quadratic optical nonlinearity of composites was studied depending on temperature and time of dissolution of crystals in the glass matrix. Conditions for producing transparent nanocomposites that generate the second optic harmonic are identified. [ABSTRACT FROM AUTHOR]

The article presents the implementation of CFD/FEM approach for real oil tank of the gas turbine engine for the purposes of prediction of the component behavior under the local impact of a burner jet. The model takes into account heat and mass transfer problems as well as strength problems that are solved using a one way coupled fluid-structure interaction method. Results of the blind test simulation are compared and show good agreement with available experimental data. [ABSTRACT FROM AUTHOR]

Much uncertainty remains as to the temporal relationship between the Ediacaran and Cambrian biotas, yet this is critical to our understanding of the rise of metazoans. Here we present new high-resolution carbon isotope chemostratigraphy and biostratigraphy for a terminal Ediacaran to Cambrian succession on the eastern Siberian Platform, Russia, which shows the presence of a succession of diverse fossil assemblages before the start of the basal Cambrian negative carbon isotope excursion (BACE). Soft-bodied Ediacaran biota (Beltanelliformis) occur before the start of the late Ediacaran positive carbon isotope plateau (EPIP), a mixed Ediacaran and Cambrian skeletal biota (Cloudina, Anabarites, Cambrotubulus) appears within the EPIP, and diverse Cambrian-type small shelly fossils including Protohertzina and other protocondonts, halkieriids, chancelloriids, hyoliths, hyolithelminthes, and the burrowing trace fossil Diplocraterion appear at the beginning of the BACE. These integrated data show that taxa attributed to so-called Ediacaran and earliest Cambrian skeletal biotas in fact overlap without notable biotic turnover, and thus refute the presence of a large isotope excursion coincident with mass extinction of all Ediacaran biota. We propose a new biozone, the Cloudina-Namacalathus-Sinotubulites Assemblage Zone, to precede the known small shelly fossil (SSF) zones. These observations raise doubts as to whether there is any true separation between the Ediacaran and Cambrian skeletal biotas, and suggest that there is a deep root for the Cambrian explosion of metazoans. [ABSTRACT FROM AUTHOR]

Radical reconstruction of a slow-coking plant, which makes it possible to increase productivity with respect to feedstock by a factor of 1.5, and shorten the coking cycle from 42–48 to 28 h while retaining the quality of the products obtained, is described. [ABSTRACT FROM AUTHOR]

Abstract: Ti–Al co-doped erbium tellurite glasses have been obtained by melting mixed Er2O3, TiO2 and TeO2 batches in Al2O3 crucibles. By crucible dissolution Al2O3 amounts from 11.5 to 18.6mol% were introduced in the synthesized glasses. Differential thermal analysis of glasses points to a strong dependence of glass transition temperature T g with the substitution extent of TeO2 by the doping oxides. No crystallization features are observed up to 450°C. The spectral features and decay kinetics of the infrared photoluminescence of erbium demonstrate the possibility to achieve more than 50% of quantum yield of light-emission at Er3+ concentrations as large as 1021 cm−3, with about 2ms of lifetime, 8×10−21 cm2 of stimulated emission cross section, and no saturation at pump power densities higher than 10kWcm−2. The study of the kinetics of Er–Er energy transfer suggests to ascribe these features to a particularly homogeneous dispersion of Er3+ ions in the modified tellurite network. Raman scattering measurements of the spectral distribution of vibrational modes evidence that the introduction of doping oxides leads to an increase of structural disorder without crystallization effects. [Copyright &y& Elsevier]