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The optical breakdown in water, caused by irradiation with nanosecond and picosecond laser pulses at a wavelength of 1064 nm, has been studied. It is proven experimentally that optical breakdown centers are both individual nanobubbles of dissolved gas and clusters formed by these nanobubbles. It is found that the first stage of optical breakdown on nanobubble clusters implies induced optical coalescence (collapse) of such a cluster and formation of a macroscopic vapor bubble. The obtained experimental results for nanosecond and picosecond pulses are in good agreement with the predictions of the previously developed theoretical model. [ABSTRACT FROM AUTHOR]

Ferroelectrics are essential in memory devices for multi-bit storage and high-density integration. Ferroelectricity mainly exists in compounds but rare in single-element materials due to their lack of spontaneous polarization in the latter. However, we report a room-temperature ferroelectricity in quasi-one-dimensional Te nanowires. Piezoelectric characteristics, ferroelectric loops and domain reversals are clearly observed. We attribute the ferroelectricity to the ion displacement created by the interlayer interaction between lone-pair electrons. Ferroelectric polarization can induce a strong field effect on the transport along the Te chain, giving rise to a self-gated ferroelectric field-effect transistor. By utilizing ferroelectric Te nanowire as channel, the device exhibits high mobility (~220 cm2·V−1·s−1), continuous-variable resistive states can be observed with long-term retention (>105 s), fast speed (<20 ns) and high-density storage (>1.92 TB/cm2). Our work provides opportunities for single-element ferroelectrics and advances practical applications such as ultrahigh-density data storage and computing-in-memory devices. Authors find room-temperature ferroelectricity in single element Te nanowires, highlighting that reducing dimensions to 1D in low-dimensional piezoelectric materials with chain structures is an effective strategy to induce ferroelectricity absent in their 2D form. [ABSTRACT FROM AUTHOR]

Formal domain models make it possible to build intelligent tutoring systems based on symbolic artificial intelligence that are capable of reliable error detection, generation of explanatory feedback and pedagogical questions, etc. However, developing these models for modern inference engines is a very time-consuming problem. This paper describes a method for representing domain problems and solutions in the form of decision trees and proposes a prototype framework for developing intelligent tutoring systems based on it. During the experimental development of four kernels for intelligent tutoring systems, the framework showed moderate performance, providing a significant reduction in development time. [ABSTRACT FROM AUTHOR]

Methods of predicting how temperature affects the physical and mechanical properties of polymer composites used in LED lamps are considered. By differential scanning calorimetry, the specific heat and phase changes of the polymers and samples of lamp housings are determined. In filler selection, the optimal polymer composition is taken into account. [ABSTRACT FROM AUTHOR]

Materials on the symmetrical influence of thermal fields on the side opposite to a hard-surfaced side, expressed in the same form of hardness distribution diagrams, are presented. The introduction of conditional criteria for assessing the properties of the thermally affected zone makes it possible to assess its stress state indirectly. The numerical values of the hardness of individual sections of the hardened sample are obtained. [ABSTRACT FROM AUTHOR]

The ultrashort radio wave refraction in the troposphere depends on meteorological conditions. In the present study, an atmospheric-soil measuring complex is used to measure the meteorological parameters at altitudes of 1 and 10 m for three years (2015–2017), and refraction gradients are calculated at standard meteorological times. Monthly datasets are grouped depending on the time of day to illustrate their typical diurnal behavior. The obtained data sub-arrays are analyzed using descriptive statistics. The occurrence of super-refraction is observed in the second half of day at the lake coast during the summer period. [ABSTRACT FROM AUTHOR]

Causes of the development or aggravation of cognitive impairment (CI) may include the use of a number of drugs, including non-steroidal anti-inflammatory drugs, antiarrhythmics, antidepressants, glucocorticosteroids, antitumor drugs, and various others. The adverse effects of drugs on cognitive functions are mediated by many pathophysiological mechanisms: disruption of hormonal regulation, decreased neuronal excitability, increased γ-aminobutyric acid receptor activity, decreased cerebral blood flow, and atrophic changes in the brain; many mechanisms remain to be established definitively. Risk factors for the development of drug-induced (DI) CI are old age, childhood, brain damage, chronic diseases, and genetic factors, along with the presence of early CI in the patient, polypharmacy, dose and duration of drug use, acute infectious diseases, metabolic disorders, dehydration, acute urinary retention, and others. The diagnosis and differential diagnosis of DI CI requires a connection between the start of taking the proposed drug inductor and CI to be established. The first step in the treatment of DI CI is discontinuation of the inducing drug or reduction in the dosage; when discontinuation of the drug is not possible and there is no replacement, special slow-release dosage forms can be considered. The main measures to prevent DI CI include the use of drugs with the lowest risk of their development, assessment of drug interactions, and the use of modern scales to assess the risk of developing this side effect (such as the anticholinergic burden scale). [ABSTRACT FROM AUTHOR]

Ophiolite-derived clastic rocks of the Rassokha terrane in the Chersky Range of the Verkhoyansk−Kolyma folded area were studied to obtain representative characteristics of the eroded source metamorphosed ultramafic and mafic rocks, to gain an insight into the possible geodynamic setting in which the protoliths of these rocks were formed, and to identify the possible source of the eroded material. The composition of lithoclasts and detrital minerals of the serpentinite and listwanite sandstones suggests that their source was composed of serpentinite, chloritite, listwanite, and dolomite rocks and that this source was proximal. Prior to the source erosion, the ultramafic and mafic rocks were metamorphosed and recrystallized, listwanite was formed, and the ultramafic rocks were tectonically disintegrated and combined with units of carbonate rocks (dolomite). Ultramafic rocks from lithoclasts experienced allochemical metamorphic retrogression during at least the latest stage of their serpentinization in a nonoceanic setting, where also the listwanite was formed. The Late Neoproterozoic ophiolites of the collisional belt of the Chersky Range were the most probable source for the protoliths of the clastic material. The protoliths of the ophiolite rock were probably formed in a backarc setting. Considered together with the published ages, our data indicate that relics of suprasubduction oceanic lithosphere of the Neoproterozoic basin occurred in the Chersky Range. [ABSTRACT FROM AUTHOR]

Young people use slang for identifying themselves with a particular social group, gaining social recognition and respect from that group, and expressing their emotional state. One feature of Internet slang is its active use by youth in online communication, which, under certain conditions, may cause problematic Internet use (PIU). We conducted two studies in young Russian speakers (n1 = 115, n2 = 106). In study 1, participants were asked to rate a set of slang and common words using Self-Assessment Manikin. The study revealed that the most reliable predictor of higher emotional ratings was word familiarity. There were no significant effects of slang vs. common words or word frequency. In study 2, we used a dual lexical decision task to reveal the effects of word characteristics and propensity for PIU on reaction time (RT) for Internet slang words in pairs with semantically related vs. unrelated common words. Study 2 did not reveal any significant semantic priming effect. Word frequency was a significant predictor of lexical decision facilitation. Common, but not slang, word valence and dominance significantly affected RT in the opposite direction. Individuals with higher cognitive preoccupation with the Internet responded significantly faster, while those more likely to use online communication for mood regulation responded significantly slower to the stimuli. Apparently, on explicit and implicit levels, in-depth knowledge of Internet slang can be one the PIU markers. The results are discussed in line with Davis’ approach to determining the general pathological Internet use. [ABSTRACT FROM AUTHOR]

Information security in the automated production control system at PAO Koks is discussed. Organizational and engineering aspects of security required to ensure accessibility, integrity, and confidentiality of data in the critical information infrastructure are noted. [ABSTRACT FROM AUTHOR]

The Early Permian (275.3 ± 3.1 Ma) 40Ar/39Ar plateau age of detrital mica (Cr-phengite) from clasts in listvenite sandstones of the ophiolite-derived clastic sequence of the Rassokha Terrane of the Chersky Range probably corresponds (or is close) to the time of the formation of listvenites of the provenance (ophiolitic massifs of the range) and restricts the maximum deposition age of clastic rocks. A partial loss of Ar by mica as a result of deformations and postsedimentation transformation of rocks of the ophiolite-derived clastic sequence in the Early Permian is possible but it is less probable. [ABSTRACT FROM AUTHOR]

We report experimental results of using the resonator-loss-unloading method to implement relaxation properties of a passive shutter in an Nd3+:YAG laser with the aim of producing extremely short picosecond pulses. The application of a fast relaxing passive shutter based on a technologically advanced new pyrillocyanine dye and the use of the unloading method make it possible to obtain highly reproducible, ultrashort 7-ps light pulses from this laser. [ABSTRACT FROM AUTHOR]

A method is developed for producing primary catalyst carriers in the form of honeycomb blocks using additive technologies. The composition of the molding slip is developed and its rheological properties are optimized. Block catalysts based on primary supports formed by 3D printing are obtained. It is shown that these products are highly productive in the process of the catalytic oxidation of CO with atmospheric oxygen and it is possible to further increase it due to the formation of channels of complex geometric shapes, which make it possible to intensify the processes of heat and mass transfer. [ABSTRACT FROM AUTHOR]

Betulin is a biologically active triterpenoid substance, which can be isolated from birch bark. We report on a new approach to the synthesis of betulin sulfamate with sulfamic acid and ammonium sulfamate in the presence of solid catalysts, including Amberlyst 15® and Sibunit (granules) oxidized at 500 °C, Sibunit (powder) oxidized at 400 °C, Sibunit-sulfated, TiO2, and ɣ-Al2O3. It is shown that the synthesis with both sulfamic acid and ammonium sulfamate in the presence of an Amberlyst 15® catalyst yields sulfur derivatives of betulin. This catalyst has been proven to remain active at the repeated (up to four cycles) use. A reaction scheme for the catalytic production of sulfur derivatives of betulin is proposed. The obtained sulfur derivatives of betulin have been examined by Fourier transform infrared and ultraviolet visible spectroscopy, scanning electron and optical microscopy, X-ray diffractometry, thermogravimetric analysis, differential scanning calorimetry, and elemental analysis. It has been found by Fourier transform infrared spectroscopy that the use of sulfamic acid with an Amberlyst 15® catalyst ensures the formation of betulin sulfates, while when using ammonium sulfamate with the same catalyst, the sulfate and other betulin derivatives are obtained along with sulfates. It has been established from the X-ray diffractometry data that sulfation of betulin causes its stronger amorphization. [ABSTRACT FROM AUTHOR]

Here, we report the results of qualitative and quantitative investigations of the first-order phase transition in the ionic liquid 1-ethylpyridinium triflate exhibiting a high variability of temperature ranges, within which the freezing and melting occur. By two methods, the direct fast quenching/annealing and the slow temperature-controlled differential scanning calorimeter, it is revealed that despite the almost constant absolute enthalpies of phase transition, the freezing occurs faster with the larger temperature contrast (cooling rate) between the initially hotter sample and the colder surrounding. This feature is a clear exhibition of the Mpemba effect. The regularity in the change of the melting point is analyzed as well. [ABSTRACT FROM AUTHOR]

A mathematical description of the motion of a cavity on the liquid surface under an oblique action of a gas jet is obtained using the well-known expressions for the movement of a gas bubble in a liquid. The boundary of the viscous drag force domination over the form drag force is determined. The impingement of the gas jet on the liquid surface is considered as a dynamic object of the automatic control theory. It is found that the dynamic properties of the two-phase system "gas jet–liquid" are described by the integrator equations. Using a specially designed setup, the transient response of the "gas jet–liquid" system were experimentally obtained for the aerodynamic action at angles of 20° and 50° to the surfaces of liquids with the viscosities of 0.71 and 26.1 Pa s (Reynolds number Re < 2). The research results are necessary for the analysis of the non-contact aerodynamic method of liquid viscosity measurements. [ABSTRACT FROM AUTHOR]

A model is considered for predicting the operational elastic characteristics of polymer composites based on ED-20 epoxy resin with microcapsules (polyester shells) containing vegetable oil and magnetite nanoparticles. The model is based on the generalized singular approximation of random field theory and takes account of the qualitative and quantitative composition of the frictional materials and also the characteristic size of the microcapsules and nonuniformity of their distribution over the polymer thickness. [ABSTRACT FROM AUTHOR]

This paper is devoted to the study of QCD properties affected by relativistic rotation. The presented results were obtained within the first-principle lattice simulation of gluodynamics and in QCD with dynamical quarks. We discuss how relativistic rotation influences confinement/deconfinement and chiral symmetry breaking/restoration phase transitions. We also focus on the moment of inertia of gluon plasma, which unexpectedly takes a negative value below the "supervortical temperature" , vanishes at , and becomes a positive quantity at higher temperatures. The negative moment of inertia indicates a thermodynamic instability of rigid rotation. Finally, we discuss the spatial structure of rotating gluon plasma and demonstrate the emergence of an inhomogeneous phase transition in a certain range of temperatures and rotation velocities. [ABSTRACT FROM AUTHOR]

Expressions are obtained for operators of the concentration of the electric field strength and displacement on the surface of inclusions in a matrix composite depending on the shape and volume fraction of inclusions in the material. These operators relate the fields on the inclusion surface on the matrix side with the average values of the electric field strength and displacement in the composite sample. [ABSTRACT FROM AUTHOR]

For the first time, an intermetallic 2Ni–Mn–Al-based alloy is prepared by self-propagating high-temperature synthesis (SHS) combined with centrifugal casting. According to X-ray diffraction data, the main phase of the SHS product is the (Ni,Mn)3Al nickel aluminide solid solution with the partial substitution of manganese for nickel. The study of the microstructure shows a low aluminum content at the boundaries of the (Ni,Mn)3Al main phase. The averaged microhardness of the synthesized alloy is 8500 ± 45 MPa and the peak hardness is 11500 MPa. The alloy exhibits soft magnetic properties. The maximum magnetization in a field of 796 kA/m (10 kOe) is Js = 1.1 (A m2)/kg (emu/g) and the coercive force is Hc = 14.3 kA/m (179.7 Oe). [ABSTRACT FROM AUTHOR]

One of the main characteristics of optical imaging systems is spatial resolution, which is restricted by the diffraction limit to approximately half the wavelength of the incident light. Along with the recently developed classical super-resolution techniques, which aim at breaking the diffraction limit in classical systems, there is a class of quantum super-resolution techniques which leverage the non-classical nature of the optical signals radiated by quantum emitters, the so-called antibunching super-resolution microscopy. This approach can ensure a factor of n improvement in the spatial resolution by measuring the n -th order autocorrelation function. The main bottleneck of the antibunching super-resolution microscopy is the time-consuming acquisition of multi-photon event histograms. We present a machine learning-assisted approach for the realization of rapid antibunching super-resolution imaging and demonstrate 12 times speed-up compared to conventional, fitting-based autocorrelation measurements. The developed framework paves the way to the practical realization of scalable quantum super-resolution imaging devices that can be compatible with various types of quantum emitters. Quantum super-resolution techniques take advantage of the non-classical nature of the quantum emitters, but are time-consuming. Here, the authors present a machine learning-assisted approach for fast antibunching-based super-resolution imaging, with a 12-fold speed up over the conventional approach [ABSTRACT FROM AUTHOR]

Titanium nickelide alloys have been prepared by pressure-assisted electrothermal explosion (ETE) synthesis. We have examined the effect of Joule heating power on ETE parameters and the physicomechanical properties of the synthesized alloys. The results demonstrate that raising the electrical voltage applied to the starting mixture leads to a decrease in ignition time and increase in the maximum ETE temperature. The ignition temperature was 350°C, independent of the Joule heating power. X-ray diffraction characterization showed that the major phase in the alloys was NiTi. According to uniaxial compression test results, the compressive strength of the alloys is 1980 MPa. Their microhardness HV is 6.4 ± 0.8 GPa. Instrumental indentation has been used to determine their hardness under load (HM = 9.4 GPa) and characteristics of their plastic and elastic deformation. The synthesized alloys have been shown to have high plasticity. [ABSTRACT FROM AUTHOR]

Ni–Al–Co alloy with the composition 45 wt % Ni + 41 wt % Co + 14 wt % Al has been prepared for the first time by aluminothermic reaction. The phase composition of the synthesized alloy comprises a cubic (Ni,Co)3Al solid solution of cobalt in nickel aluminide (γ'-phase) and a tetragonal (Ni,Co)3Al phase. The formation of the tetragonal structure of (Ni,Co)3Al is due to a martensitic transformation of a supersaturated initial structure in grains of the cubic (Ni,Co)3Al phase. The intragranular microhardness of the synthesized alloy is 6500 MPa. The alloy has soft magnetic properties, with the highest magnetization of 27 emu/g in a magnetic field of 10 kOe. [ABSTRACT FROM AUTHOR]

Epoxy composites with hollow glass microspheres are considered. A method is proposed for predicting their local elastic characteristics and limiting strength characteristics in uniaxial compression. The method takes account of the composition of the material, the content of the components in the syntactic foam, and the characteristic size of the microspheres (the ratio of the shell thickness to the cavity radius). The variation in these parameters is taken into account in model calculations. [ABSTRACT FROM AUTHOR]

Abstract—The physicochemical and service properties of new complex Nb–Si–Al–Fe–Ti alloys containing (wt %) 0–25 Si, 20–23 Nb, 5–6 Al, and 3–4 Ti are studied and compared with the well-known two-component Fe–60% Nb alloy. The two-component Fe–Nb alloy belongs to the group of super-refractory ferroalloys with a solidification temperature of 1720°C. A decrease in the niobium concentration and an increase in the content of Si, Al, and Ti make it possible to transfer the alloys to the group of refractory ferroalloys with a melting temperature of 1550–1584°C. The lowest solidification temperature (1550°C) is characteristic of an alloy containing the maximum silicon content (25 wt %) and the minimum niobium content (20 wt %). A pycnometric study of the densities of the complex ferroalloys shows that an increase in the silicon concentration to 21–25 wt % leads to a decrease in the alloy density to optimum values (5000–7000 kg/m3). The melting of the complex niobium alloys with a lump diameter of 2–100 mm in an iron–carbon melt under static conditions has been studied by mathematical modeling. The melting of all complex alloys is found to proceed in three stages. Due to high melting temperatures, super-refractory ferroalloys, which include the two-component alloy with 60 wt % Nb, dissolve at the temperature of liquid steel; therefore, their assimilation mechanism proceeds in two stages. The alloy containing 25 wt % Si and 20 wt % Nb has the shortest melting time at all lump sizes. The ferroalloy lump size is shown to affect the melting/dissolution time most strongly. This is explained by the fact that the alloy mass increases with the lump size, which brings about an increase in the heat content and the frozen steel skin thickness. The complex alloys are shown to have the most favorable densities and solidification temperatures as compared to standard ferroniobium. The alloy containing (wt %) 25 Si, 20 Nb, 5 Al, and 3 Ti has the best complex of physicochemical and service properties. [ABSTRACT FROM AUTHOR]

This paper reports on structure and phase formation of a Ni–Al–Co based alloy prepared by self-propagating high-temperature synthesis. The maximum combustion temperature was 1020°C in argon and 913°C in vacuum. The phase composition of the synthesized alloy includes a Ni0.7Co0.3 solid solution with a cubic (Pm m) crystal lattice. Its microstructural constituents based on γ- and β-phases are 10–20 μm in size, and γ + β interlayers located on the interface between the γ- and β-phases are up to 1–2 μm in thickness. The alloy offers high plasticity, and its compressive strength is 451 MPa. Its low remanence, low coercive force, and high saturation magnetization indicate that the alloy is a soft magnetic material. It has a coercive force Hc = 146 Oe, remanent magnetization σr = 0.35 emu/g, and saturation magnetization σs = 36.76 emu/g. [ABSTRACT FROM AUTHOR]

The results of the study of the nonlinear propagation of the laser beam of an ultrashort pulse 25 ps long in the self-focusing mode in degassed water are presented. The optical breakdown conditions and frequency-angular characteristics of radiation emerging from the beam focal waist were studied. It was found that the formation of a narrowly directed radiation shaped as a light filament, swept in frequency in a wide frequency range at a simultaneous appearance of laser beam self-focusing effects and plasma breakdown of water. [ABSTRACT FROM AUTHOR]

An alloy based on the Laves phase Ti(Mn0.75Al1.25) has been prepared by self-propagating high-temperature synthesis using a 34.8Ti + 45.2Al + 20Mn (at %) mixture. The relative density of the as-prepared samples has been shown to influence the phase composition of the alloy. In the case of a relative density of ~0.75, we obtained a single-phase intermetallic alloy with a porosity of 45%, containing ~2 wt % of Al2O3 as an impurity phase. Synthesis from a mixture with a relative density of 0.55 yielded a two-phase alloy containing a Laves phase and the τ-Ti(Al2.68Mn0.32) phase. The alloy was in a nonequilibrium state, and annealing at 1000°C for 3 h led to the formation of a single-phase alloy based on the Laves phase Ti(Mn0.75Al1.25). Its microhardness was determined to be 7.96 ± 0.8 GPa. [ABSTRACT FROM AUTHOR]

Fine grinding in mills of various types is of great interest today. Comparison shows that vibrational mills are best for fine grinding. Designs of vibrational mills are considered, as well as approaches to their improvement. The structure and operational principle of a mill with polyharmonic vibration of the grinding chamber are outlined. The motion of the cylindrical housing in a new mill design with polyharmonic vibration of three vibration sources for superfine grinding is mathematically described. On that basis, the center-of-mass position of the mill's grinding chamber relative to the OX and OY coordinate axes is analytically determined. The kinetic energy and potential energy of the grinding bodies are calculated, as well as the vibrational amplitude of the charge's center of mass relative to the OX and OY axes. [ABSTRACT FROM AUTHOR]

An approach is proposed to reduce the stability of the cubic phase of lead selenide by thermal oxidation with atmospheric oxygen and its transformation into an ordered monoclinic phase of lead selenite. An estimated thermodynamic analysis (TA) of the course of possible chemical reactions of lead selenide oxidation with oxygen is carried out. The kinetics of lead selenide oxidation with atmospheric oxygen are studied by X-ray emission analysis, X-ray diffractometry, optical reflection in the infrared region of the spectrum, studies of conductivity in direct and alternating currents, and nuclear magnetic resonance. For the PbSeO3 structure, the Goldschmidt stability factor was estimated and it was shown that the structure can be classified as perovskite-like and have ferroelectric properties. [ABSTRACT FROM AUTHOR]

Experiments on time-dependent stimulated Raman scattering (SRS) and optical breakdown in the field of a picosecond laser pulse were performed with water samples containing gas nanobubbles (bubstons) with different concentrations. It is found that an optical breakdown in water contacting with atmosphere for a long time leads to the occurrence of an anomalously strong low-frequency SRS line at a frequency of ≈700 cm–1; its intensity significantly exceeds that of the SRS line at the frequency ≈3410 cm–1, which is due to the O–H stretching vibration of water molecules. A hypothesis about generation of a resonant plasmon during bubston breakdown in water was proposed to explain the observed effect. It is shown that the resonant plasmon was excited due to the pump wave beating and low-frequency Stokes scattering wave, shifted by the frequency of librational vibration of water molecules. [ABSTRACT FROM AUTHOR]

Amongst the modern problems of brain physiology, special attention is drawn to the transport processes in the brain's extracellular space, which are crucial for understanding metabolic exchange, waste clearance, etc. At the same time, the complexity of direct registration of such processes in vivo forms a demand for developing artificial phantoms with properties resembling the brain's parenchyma as models suited for testing different physical approaches to describing the respective spread of substances. Here we describe a novel hydrogel material with composition and structure adjusted to this goal. The phantom comprises a collagen network with the addition of lipids and catches water content close to that of the brain. The results of electron microscopy and computer tomography studies as well as exploration of peculiarities of the fluorescent marker spread argue that this compound material is prospective for its use for mimicking the brain's tissue. [ABSTRACT FROM AUTHOR]

The results of experimental and computational studies of torrefaction (low-temperature pyrolysis) of granular plant biomass are presented. As a result of this process, high-quality solid hydrophobic biofuel with increased calorific value is obtained from biomass of various types (including waste). Unlike fossil coal, torrefied fuel contains virtually no sulfur and heavy metals, has a lower ash content, and is a carbon-neutral product. The carbon dioxide released during the combustion of plant biofuels is completely absorbed during the period of plant growth. Biofuels are a renewable resource. The annual increase in biomass is 400 billion t, and the rate of energy accumulation by terrestrial biomass is 3 × 1021 J/year. The article considers a vertical reactor with a dense layer of pellets moving towards the heating gas flow under the action of its own weight and features of its operation, taking into account the possible implementation of the concept of a controlled exothermic reaction. To ensure the set mode, the plant has two control units: for controlling and maintaining the set temperature of the coolant at the reactor inlet and for controlling the opening of dampers for unloading finished products into the cooling zone. Experimental and calculated data are presented for three characteristic operating modes of the installation: with limitation of the exothermic reaction due to the control of the inlet temperature, with a controlled exothermic reaction, and with the production of biochar. The second mode turned out to be the most energy efficient. The deviation of the calculated data from the experimental data was no more than 4%. It is shown that the use of the energy of an exothermic reaction can significantly increase the energy efficiency of the process of obtaining carbon-neutral solid biofuel. [ABSTRACT FROM AUTHOR]

The effect of uniform rotation on the equation of state of gluodynamics has been studied in lattice simulation. To this end, the system has been considered in the corotating reference frame, where the rotation can be modeled as an external gravitational field. The free energy of the studied system in the case of sufficiently slow rotation can be expanded in a power series in the angular velocity. The moment of inertia given by the second-order coefficient of this expansion has been calculated and its dependence on the temperature and the dimensions of the rotating system has been determined. Our results indicate that the moment of inertia of gluodynamics is negative up to the temperature T * ~ 1.5Tc, where Tc is the critical temperature of the confinement/deconfinement phase transition, and becomes positive at temperatures T > T *. The negative moment of inertia has been attributed to the thermodynamic instability of the gluon plasma with respect to uniform rotation. [ABSTRACT FROM AUTHOR]

The paper provides brief information about the state of production and use of niobium in steelmaking and about niobium deposits in Russia. Pyrochlore-apatite ores contain a significant amount of phosphorus; therefore, the schemes of their enrichment include a dephosphorization stage, which reduces the niobium extraction into the product, increasing its cost. The possibility of improving the through production scheme, including the enrichment of ores and the smelting of niobium ferroalloy, is shown. The smelting process and the physicochemical characteristics of the used concentrates of the CaO– SiO2–MgO–Al2O3–TiO2–Nb2O5–Fe2O3–P2O5 system have not been sufficiently studied; therefore, thermodynamic simulation of carbothermal and metal-thermal processes of reducing the oxide system components was performed in order to determine the influence of chemical composition of the system, the amount of reducing agent and temperature on the reduction degree of elements, the composition of the metal and oxide phases, and the metal dephosphorization. Thermodynamic simulation was carried out for temperatures of 1400–1700 °C at a reducing agent consumption of 80, 100 and 120% of the stoichiometrically required amount for the reduction of the system leading elements. With the carbothermal method, the phosphorus reduction occurs quite completely at more than 100% of carbon of the stoichiometrically required amount already at 1100°C and above. With the silicothermal method, the influence of temperature and silicon amount on the reduction degree of Nb, P, Ti and the chemical and phase compositions of the alloy is shown. [ABSTRACT FROM AUTHOR]

An axisymmetric incompressible flow past Rankine's half-body of revolution is investigated at high Reynolds numbers. It is established that the solution of the problem for the system of boundary layer equations does not involve the line of zero surface friction. The low under consideration is separationless, which is in complete agreement with the available experimental data. [ABSTRACT FROM AUTHOR]

The dielectric properties of BN–ZrB2 and BN–ZrO2 based ceramic materials synthesized by self-propagating high-temperature synthesis (SHS) from a powder mixture (boron B, boron nitride BN, and zirconium dioxide ZrO2) in a nitrogen N2 atmosphere were investigated. The experimental results showed that the ceramic synthesized from the initial mixture with the composition (30B + 10ZrO2 + 60BN, wt.%) possesses room-temperature dielectric permittivity ε = 2.63 and dielectric loss tangent tan δ = 0.006. [ABSTRACT FROM AUTHOR]

Introduction: Human cytochrome P450 (CYP) enzymes have a wide range of endogenous substrates and play a crucial role in cardiovascular physiology as well as in metabolic processes, so the issue of cytochrome P450 genes investigation has received considerable critical attention in the prevention of cardiovascular diseases (CVDs). Aim: Comprehensive assessment of relationship between CYP2C19*2, CYP2C19*3 polymorphisms and CVD risk factors in gas industry workers undergoing periodic medical examination (PME). Materials and Methods: The study included 193 gas industry workers aged 30–55 years without acute diseases as well as exacerbations of chronic diseases, diabetes mellitus, and CVD history. CYP2C19 (rs4244285 and rs4986893) genotyping and analysis of the relationship between CYP2C19*2 and CYP2C19*3 and CVD risk factors were performed. Results: The CYP2C19*2 (A) and CYP2C19*3 (A) loss-of-function alleles frequencies were 20% and 2%, respectively. The frequency of high-normal blood pressure (BP) (130–139 and/or 85–89 mm Hg) detection was higher in the CYP2C19*2 (A) subgroup compared with wild-type GG allele carriers (26.7% vs. 5.2%, p = 0.03) in individuals without arterial hypertension (AH) and BP ≥ 140 and/or 90 mm Hg on PME. The median systolic BP levels were 5 mm Hg higher in CYP2C19*2 (A) group than in CYP2C19*2 (GG) group (125 vs. 120 mm Hg, p = 0.01). There was a similar trend for diastolic BP (85 vs. 80 mmHg, p = 0.08). CYP2C19*2 (A) was associated with higher mean levels of both systolic and diastolic BP (p = 0.015 and p = 0.044, respectively) in patients with AH. CYP2C19*2 was not associated with the other CVD risk factors analyzed. Conclusion: The association of CYP2C19*2 with BP level suggests a possible role of this factor in AH development, which requires further research. [ABSTRACT FROM AUTHOR]

Detonation spraying is of great interest currently. In this method of coating application, the powder is heated and accelerated by means of a gas-phase explosion. This approach is economical and produces coatings of high density and adhesion, which is of great importance. The development of a new detonation gun employs a digital twin—that is, a complete copy of the physical object produced by means of special software—and complies with the appropriate technical specifications. The main stages in constructing the digital model are considered. [ABSTRACT FROM AUTHOR]

The grinding of material in a vibrational mill is considered. Grinding is regarded as a random process consisting of a series of uniform events. The process is assumed to be steady, simple, and ordinary. We interpret grinding in a vibrational mill as a random Markov process. The calculation is based on the Kolmogorov equation. The motion of the grinding bodies in the mill is assumed to be accompanied by simultaneous interaction with all the particles of the material to be ground. A kinetic equation is obtained for the grinding process. This equation permits calculation of the particle size at any time on the basis of its initial size. The calculation of the grinding kinetics is illustrated by an example, and the calculation results are analyzed. [ABSTRACT FROM AUTHOR]

A brief review of noncontact methods for measuring the viscosity of liquids is given. It is shown that it is advisable to use the pulsed aerohydrodynamic method for high viscosity measurements (more than 10 Pa·s). The essence of the method is described; it consists in deforming the tested liquid surface by a gas jet and determining the viscosity by the time it takes to reach a certain deformation degree from the moment when the jet is applied. Two models and two functions for measuring viscosity by the pulsed aerohydrodynamic method were obtained theoretically, and the lower limit of viscosity measurements was theoretically assessed. Two models for measuring viscosity were experimentally studied at aerodynamic action angles of 20° and 50° with the compensation of transient process at the moment of solenoid valve opening and without it. It has been established that to determine the viscosity by the time it takes to reach a certain degree of liquid surface deformation, it is advisable to use a linear measurement function, not to compensate for the transient process in the pneumatic system, and to use the aerodynamic action at an angle of 20–30° to the liquid surface. It has been experimentally proved that the relative error of viscosity measurements is not more than 3% in the range of 0.5–100 Pa·s. The results are useful for increasing the efficiency of measuring the viscosity of liquids in mechanical engineering, paint and varnish, food, chemical, electrical, and oil industries. [ABSTRACT FROM AUTHOR]

Abstract—The effect of electron-beam treatment (EBT) and heat treatment (HT) of silica-based aggregates and mineral additives in Portland cement mortars on the intensity of alkali-silica reactions (ASRs) with their participation, which are dangerous for concrete structures, is studied. It is established that heating to a temperature of 900°C and the EBT of sand free of alkali-reactive inclusions, leads to a significant increase in the reactivity of cement-sand mortar mixtures, which increases with an increase in the absorbed dose and a corresponding increase in the content of acid hydroxyl groups on the sand surface. In the case of sand containing reactive inclusions of chalcedony, EBT leads to an increase in reactivity, and HT, to a decrease. Treatment of microsilica and metakaolin mineral additives capable of ASR inhibition leads to an increase in their inhibitory effect. The results obtained are promising for modeling the expansion of concrete as a result of ASR and increasing their resistance to fracture in alkaline media. [ABSTRACT FROM AUTHOR]

The possibility of using self-propagating high-temperature synthesis to obtain high-temperature cermet materials and non-removable layer compounds based on (Ni–Al)/oxide, where the oxides are SiO2, Al2O3, and 3Al2O3·2SiO2, was investigated. A thermodynamic analysis of the combustion reactions was carried out. The properties of the synthesized products were investigated. The alternative method of creating layered materials with various contents of oxide phases opens wide possibilities for their use as heat insulators and special elements for high-temperature applications. [ABSTRACT FROM AUTHOR]

Existing ball mills of drum type are analyzed. Their advantages and disadvantages are identified. Possible means of improving the grinding efficiency are noted. A fundamentally new ball design is proposed. Equations are derived for calculating the total and consumed power in transverse and longitudinal ball motion within both drum chambers. Formulas are presented for the loading factor and the power consumed. As an example, the maximum permissible loading factor for a drum is calculated, as well as the drive's additional power consumption. A nomogram is presented for determining the loading factor. The influence of the ball mass on the power consumption is shown graphically. [ABSTRACT FROM AUTHOR]

The results of a study of the pyrolysis of dried sewage sludge taken from a fixed-bed reactor of urban wastewater treatment plants are presented. The obtained experimental data made it possible to estimate the migration activity of heavy metals entering into the composition of the sewage sludge. Measurements were carried out for vanadium (V), chromium (Cr), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), strontium (Sr), lead (Pb), rubidium (Rb), barium (Ba), zirconium (Zr), and arsenic (As). It is shown that the emission of heavy metals upon release of volatile substances during pyrolysis is characteristic for almost all of the studied elements, among which As, Rb, Co, and Ba are the elements having the highest migration activity. [ABSTRACT FROM AUTHOR]

The possibility of using self-propagating high-temperature synthesis to obtain high-temperature cermet materials and non-removable layer compounds based on (Ni–Al)/oxide, where the oxides are SiO2, Al2O3, and 3Al2O3·2SiO2, was investigated. A thermodynamic analysis of the combustion reactions was carried out. The properties of the synthesized products were investigated. The alternative method of creating layered materials with various contents of oxide phases opens wide possibilities for their use as heat insulators and special elements for high-temperature applications. [ABSTRACT FROM AUTHOR]

The problem of constructing a correct topic model is relevant for the automatic processing of large collections of text messages tasks. This paper considers an approach to the topic categorization assessing for a collection of short text messages (labeled up by experts) based on the clustering of terms that make up the message text. The results of a computer experiment on clustering a set of terms are presented and discussed. As part of the experiment, a graph was constructed that reflects the relations and some numerical characteristics of the terms that form the topic model for a collection of messages. Analysis of the structure of the graph allows one to generate some practical recommendations for reorganizing the topic model presented in the expert labeled text collection. [ABSTRACT FROM AUTHOR]

We have studied the effect of a small aluminum addition on the phase composition, microstructure, and physicomechanical characteristics of a Ti–B based metal–ceramic composite produced by self-propagating high-temperature synthesis compaction. The results demonstrate that the addition of 2 wt % aluminum increases the percentage of TiB2 and α-Ti in the structure of the composites. Evaluation of the unit-cell parameters of titanium by the Rietveld method (with Jana2006 software) has shown that co-alloying with oxygen and aluminum reduces the unit-cell volume of titanium and stabilizes α-Ti. The composites alloyed with Al have higher compressive strength and lower microhardness (HV) owing to the larger percentage of the Ti binder. [ABSTRACT FROM AUTHOR]

Automated assessment of felt reports in accordance with the regionalized DYFI questionaries were implemented on mobile applications and messengers of the seismological service eqalert.ru. The new tool was tested on Sakhalin Island, which is considered as an active crustal region. We have developed a regression relationship between the peak ground acceleration and the community internet intensity for the studied area. The community internet intensity calculated from a large number of felt reports has a variance comparable to those given from a prediction equation of the physically based ground motion parameters. The given approach is considered as a state-of-art tool for the rapid collecting and assessment of macroseismic data. It may be used both with the weighted average method for generating high-quality shaking maps immediately following the felt earthquake. It is also a good way to involve the population in ground shaking measures. [ABSTRACT FROM AUTHOR]

To improve the characteristics, samples of diamond–carbide silicon composite were subjected to microwave processing. The products were placed in a microwave oven chamber, in a zone with maximum electric field intensity. As a result of processing, it was possible to increase the density of samples by 7%, as well as reduce porosity by more than an order of magnitude. [ABSTRACT FROM AUTHOR]