Search

A significant number of different types of damage to structural materials, as well as various scenarios of their accumulation, up to destruction, require not only the use of a significant set of experimental methods and the methods of theoretical materials science and molecular physics, but also for developing appropriate mathematical models. These models perform two functions. On the one hand, they make it possible to give a reasonable interpretation of complicated processes, and, on the other hand, they can forecast the evolution of the material under specific operating conditions. Some features characterizing the description of material degradation and destruction based on kinetic approaches are considered. [ABSTRACT FROM AUTHOR]

Two-high screw rolling of stainless-steel billets at feed angles of 6, 12, 18, and 24° was numerically simulated. It was established that increasing the feed angle of the rolls decreases the magnitude and inhomogeneity of the shear strains in the billet cross-section. With increase in the feed angle, the difference between the total velocities zone on the surface and at the center of the billet in the deformation decreases by 57%, the length of the geometric deformation zone decreases, and the length of the actual deformation zone increases by 16%. [ABSTRACT FROM AUTHOR]

This study investigates the relationship between emotional trends derived from X platform data and the market dynamics of prominent cryptocurrencies—Cardano, Binance, Fantom, Matic, and Ripple—during the period from October 2022 to March 2023. Utilizing SenticNet, key emotions such as fear and anxiety, rage and anger, grief and sadness, delight and pleasantness, enthusiasm and eagerness, and delight and joy were identified. The emotional data and cryptocurrency price data, sourced bi-weekly, were analyzed to uncover significant correlations. The findings reveal that emotions such as delight and pleasantness and delight and joy have the strongest positive correlations with Fantom's price, while delight and pleasantness exhibit the strongest negative correlations with Cardano and Binance. The study highlights the nuanced impact of specific emotional states on cryptocurrency prices, offering valuable insights for market participants. [ABSTRACT FROM AUTHOR]

Adequate mathematical models of the mechanical properties of particle-reinforced polymer composites (PRPCs) require verification, which is difficult to do for at least the following reasons: lack of information on the mechanical characteristics of the transition layer formed at the modified particle–polymer interface, and lack of information about the mechanical characteristics of agglomerates that inevitably form during PRPC fabrication. This paper proposes a mathematical model for calculating the effective mechanical properties (bulk modulus, shear modulus, Young's modulus, and Poisson's ratio) of PRPCs with encapsulated filler particles. The model is verified on PRPC specimens with inclusions in the form of air bubbles. Simplified equations are derived for calculating the effective mechanical properties of PRPCs with low-modulus inclusions in the form of air bubbles. It is shown that the proposed model provides reliable estimates of the bulk modulus, shear modulus, Young's modulus, and Poisson's ratio of PRPCs at a small relative volume of submicron-sized filler particles in the matrix. [ABSTRACT FROM AUTHOR]

The structural features and phase composition are examined in near-surface layers of specimens of Al-Mg, Al-Cu-Mg alloys and commercially pure titanium obtained by plasma cutting using direct current straight polarity (DCSP) and direct current reverse polarity (DCRP). It is found that the flows of molten metal ejected by the gas stream from the cut cavity during cutting form the fusion and heat-affected zones, whose structural morphology, phase composition, and thickness depend on both the selected material and the cutting mode. The fusion zone is thicker in specimens cut using DCRP than in those cut with DCSP. The thickness of the adjacent heat-affected zone is also the largest in the mode that provides a thicker fused layer. Aluminum alloy specimens cut in ambient air are characterized by the presence of oxygen in the near-surface layers. The lowest degree of oxidation is observed in Al-Mg alloy. Oxygen penetrates into the fused layer to a depth of 350–500 μm in Al-Cu-Mg and up to 200–250 μm in Al-Mg alloy. In titanium alloy, the thickness of oxide layers does not exceed 100–150 μm during straight polarity cutting and 200–250 μm during reverse polarity cutting. A thin brittle layer of TiO and TiO2 oxides is formed on the titanium alloy surface. It is shown that the generation of "water mist" around the plasma jet when cutting materials of all types with DCRP leads to a more intensive oxidation of metal, less thermal effect on the material, and reduced roughness of the cut face. [ABSTRACT FROM AUTHOR]

The current stage of development in metallurgy is characterized by unprecedented attention to reducing CO2 emissions. Replacement of carbon with hydrogen in smelting of cast iron is a method of reducing CO2 emissions; however, the production of hydrogen is also associated with CO2 emissions. The carbon monoxide utilization rate during indirect reduction in a blast furnace is 28–38%, in contrast to direct reduction, in which the utilization rate is more dependent on contact area between the reducing agent and oxides. Use of ore-coal briquettes is a promising direction for increasing the utilization rate of the reducing power of carbon in a blast furnace. The study investigates the efficiency of using ore-coal briquettes in production of vanadium cast iron from the perspective of reducing CO2 emissions. We show that carbon consumption for direct reduction of titanium-magnetite concentrate is six times lower than for indirect reduction. Using ore-coal briquettes in blast furnace charge can reduce the specific fuel carbon consumption in production of vanadium cast iron, which will reduce CO2 emissions. [ABSTRACT FROM AUTHOR]

Narrowly divergent high-energy electron beam is experimentally demonstrated during the interaction of terawatt Ti:Sa laser radiation with a nitrogen gas-cluster jet at gas pressure corresponding to the boundary of the condensation region. A collimated electron beam with an energy of up to 10 MeV and a divergence of 10 mrad at a plasma concentration of ~1019 cm–3 is obtained. The use of nitrogen instead of argon or krypton significantly improves the spatial (divergence) and energy (charge and spectrum shape) properties of the generated electron beam. The formation of clusters in a supersonic jet is observed and their composition is thermodynamically analyzed. [ABSTRACT FROM AUTHOR]

Conformational changes in DNA and protein biomolecules were studied in ischemic stroke (IS) cases varying severity by Raman spectroscopy. The conformational structure of hematoporphyrin was found to change in IS patients, leading to a higher (I1355/I1550)/(I1375/I1580) ratio (hemoglobin affinity of for ligands) and an increase in I1375/I1172 (a change in pyrrole conformation). Changes in genomic DNA spectra were observed at frequencies caused by stretching vibrations of primary amines (3400 cm–1), secondary amines and hydroxyls involved in hydrogen bonding (3100 cm–1), and CH2 groups of sugar phosphates (2900 cm–1) and vibrations of vibrational bonds between nitrogenous bases and sugars (1400 cm–1). The significant changes observed in genomic DNA and hemoglobin spectra were assumed to indicate conformational rearrangements of the molecules in IS. Severe IS was associated with maximum changes in DNA and hemoglobin spectra. [ABSTRACT FROM AUTHOR]

The He isotopic composition and the He and Ne ratio of fluid inclusions in magnetite and pyrite from carbonatite breccias of the Sallanlatva alkali-ultramafic complex of the Kola alkaline province (Northwest Russia) are studied using the step-crushing method. The results indicate the highly likely involvement of fluids from several sources trapped in various proportions during the formation of the Sallanlatva explosive carbonatite breccias. The R/Ra ratio, where R is the measured 3He/4He ratio and Ra of 1.382 × 10–6 is the same ratio of atmospheric air, reaches 2.3, which is a reliable indicator of the presence of mantle gases. A low (1–44) 4He/20Ne ratio allows us to suggest the involvement of atmospheric gases dissolved in paleometeoric waters. A combination of these two facts favors a hypothesis of the phreatomagmatic nature of the studied breccias, i.e., their formation at the expense of interaction between the intruding hot orthomagmatic fluids and meteoric waters with dissolved atmospheric gases. [ABSTRACT FROM AUTHOR]

The work is devoted to determining the characteristics of turbine stages in off-design modes that arise when pressures and temperatures change before or after the stage, a transition to a different rotation speed, or, for example, when the composition of the working fluid changes. As part of the project, a quasi-one-dimensional method for calculating the characteristics of a turboexpander assembly (TEA) stage when changing operating parameters and/or working fluid has been developed, which differs from known methods by using the equations of the state of real gas, adaptation to purely radial stages, and a simplified approach to determining the pressure at the outlet of the guide vane for assessing the degree of reactivity and the ability to switch to another working fluid, including a mixed one. The analytical methodology was verified by comparison with the experimental data of other authors and the results of calculations using CFD methods for radial-axial stages as well as with approaches to the calculation of purely radial turbomachines due to the lack of experimental data for this type of TEA in the public domain. An extended characteristic of a radial stage operating in air (turbo map) was constructed, and the dependences of the isentropic efficiency, degree of reactivity, mass flow and power of the stage on the relative circumferential speed were assessed. An assessment was made of the impact of switching to another working fluid (for example, switching from air to methane was chosen). It is shown that the characteristics do not change qualitatively but they shift from one another along the axis of the relative peripheral velocity. Further development of the technique involves taking into account possible phase transitions (volume condensation) in the flow part. [ABSTRACT FROM AUTHOR]

The paper investigates the structure and properties of the surface layers of AA5056 and AA2024 aluminum alloy plates 35 to 40 mm thick after reverse-polarity plasma cutting. It is shown that for alloys with varied parameters of the heat capacity, plasma cutting conditions are the same. At the best plasma cutting parameters, the cut geometry shows the lowest distortion. It is found that the cutting surface distortion occurs in exceeding the optimum heat input of the plasma arc. Conversely, at the reduced heat input, the alloy plate cannot be cut to its full thickness. Most of cutting modes provide the higher surface roughness, while the roughness of the upper edge cut reduces relative to the central and lower areas. [ABSTRACT FROM AUTHOR]

The paper focuses on plasma cutting of AA5056 and AA2024 aluminum alloy sheets. It is shown that at the minimum thicknesses, the upper edge of the sheet tends to undercut when using reverse polarity. This phenomenon considerably diminishes when using the best cutting conditions. In the case of the AA2024 alloy, most of the material remains in the cutting zone, adhering to the surface and forming a substantial zone of melting or beading. The AA2024 alloy demonstrates a greater oxidation and hardening of the cutting surface. Degraded material layers and surface roughness reduce when using the best cutting conditions. The upper edge of both alloys is more homogeneous and exhibits less roughness than the lower edge. This is attributed to a more complex displacement of the metal relative to the lower edge undercut. [ABSTRACT FROM AUTHOR]

The electrophilic alkylation of dianions of fullerene derivatives generated by deprotonation of the corresponding dihydrides is described, using the example of the regioselective synthesis of a trifunctional derivative C70(CF3)8(CH3)H with a near-equatorial location of all addends. The structure of the first synthesized compound is established by means of mass spectrometry and one- and two-dimensional NMR correlation spectroscopy. The reasons for the high regioselectivity of the formation of the single isomer C70(CF3)8(CH3)H are explained using quantum chemical calculations at the level of density functional theory for isomers of anionic intermediates and the product. Electron absorption and fluorescence spectroscopy are used to demonstrate the fundamental effect of the near-equatorial location of addends in the C70(CF3)8(CH3)H compound on its optical and fluorescent properties. [ABSTRACT FROM AUTHOR]

From the 1980s to the present, a set of geophysical methods has been implemented in southeast Kamchatka, including the earthquake converted waves method, magnetotelluric sounding, gravimetry, magnetometry, and seismology. Based on a comprehensive interpretation of the data obtained, a geological and geophysical model of the Earth's crust and upper mantle along the Khodutka Bay–village of Nikolaevka profile was constructed. A genetic relationship has been established between dynamically active areas of the Earth's crust with gold deposits. A hypothesis has been put forward about the division of a previously single xenoblock into two separate fragments under the action of strike-slip faults along the Nachikinskaya transverse dislocation zone. The southern fragment is represented by the Pribrezhny Terrane. To the west of the terrane is a permeable zone in which modern volcanism has occurred. The intrusion of magma and high-temperature fluids enriched in noble metal solutions into the upper layers of the crust occurs through a magma conduit formed in the palaeosubduction zone. [ABSTRACT FROM AUTHOR]

A series of mixed-carboxylate EuCd compounds with 1,10-phenanthroline (phen) and anions of benzoic H(Bz), pentabenzoic H(Pfb), 3,5-dinitrobenzoic H(3,5-Nbz), and 3,5-di-tert-butylbenzoic H(Dtbbz) acids is synthesized: [Eu2Cd2(phen)2(Рfb)5,4(Bz)4,6]·2MeCN (I), [Eu2(H2O)2Cd2(phen)2(3,5-Nbz)4,1(Bz)5,9] (II), and [EuCd2(EtOH)4(Dtbbz)6(Pfb)] (III). The variation of combinations of aromatic anions makes it possible to reveal the influence of diverse factors on the compositions and structures of new compounds. In the case of benzoate‒pentafluorobenzoate compound I and 3,5-dinitrobenzoate‒benzoate compound II, the aromatic substituents of the anions have nonintegral populations and occupy close positions in the structure of the complex. The combination of the more bulky 3,5-di-tert-butylbenzoate and pentafluorobenzoate anions in compound III results in the formation of a compound with integral populations of the positions of the anions. The synthesized compounds are characterized by XRD, IR spectroscopy, and C,H,N elemental analysis. [ABSTRACT FROM AUTHOR]

The results of preliminary experiments on measuring the spatial asymmetry of plasma flows in the GOL-NB device using movable Mach probe are presented and the diagnostics used is described. In the experiments, the high-field sections were mounted in the configuration with solenoidal magnetic field. The dynamics of plasma flows was recorded which was expected in the trap: the plasma flowed from the plasma gun along the magnetic field, accumulated in the GOL-NB central trap, and then after the plasma gun was switched off, flowed out from the central trap in two directions. At time of transition from the stage of plasma accumulation to the stage of its decay, the direction of plasma flow in the input high-field section was inverted. The balance of particles in the central trap is discussed. Experiments have shown that this technique can be used for studying the effects of improving plasma confinement after switching to the multiple-mirror configuration of high-field sections, in which, according to theory, under optimal conditions, a flow of b-ackscattered particles should arise, which will return them from the multiple-mirror sections to the confinement zone. [ABSTRACT FROM AUTHOR]

Electrical resistivity of Co48Fe25Si4B19Nb4 amorphous alloy and with small additions of rare-earth metals (= Nd, Sm, Tb, Yb) was studied using the AC four-probe method. It was found that these alloys have a specific behavior of electrical resistivity after crystallization-temperature dependences of resistivity at cooling are non-linear and can be fitted as ln R ~ T−1/4. [ABSTRACT FROM AUTHOR]

Applying numerical modelling approach the accuracy in determining the distance between underwater sound sources and receivers is assessed at a range of several kilometers from each other in the Kara Sea in autumn. It is suggested that the main source of errors in determining the distance is the lack of accurate data on the vertical sound speed profile along the acoustic signal propagation path. Data from September and November were analyzed, in the interval between which significant changes in the profile take place, when the vertical sound speed gradient changes from negative to positive. Characteristic values of sound speed variations were obtained by statistical processing of hydrological data taken from the World Ocean Database. The results are important for analyzing the capabilities of underwater acoustic navigation. [ABSTRACT FROM AUTHOR]

This study presents the sulfur isotopic characteristics in baryte from carbonatites of the Sallanlatva massif and sulfides (mainly pyrite and pyrrhotite) from carbonatites, phoscorites and products of their contact interaction with the host silicate rocks of most carbonatite-bearing complexes of the Devonian Kola Alkaline Province (KAP). For some complexes (Ozernaya Varaka, Kontozero), these characteristics are reported for the first time. The determined range of δ34S variations of sulfides in one complex does not exceed 4‰, but reaches 20‰ for the entire Kola Alkaline Province. This may be related to the evolution style of carbonatites and associated rocks. It is shown that the δ34S value in sulfides decreases from (1) the least evolved volcanic carbonatites of the Kontozero complex (δ34Savg. = –1.3‰) through (2) carbonatites and phoscorites of the Kovdor, Ozernaya Varaka, Sokli, and Salmagora massifs towards (3) the rocks of Seblyavr, Vuoriyarvi, and, finally, the carbonatites of Sallanlatva (δ34Savg. = –14.7‰) massifs, where sulfides differ from those of other KAP carbonatites in their exceptionally low δ34S values. The carbonatite volcanics of Kontozero are almost barren of REE mineralization; carbonatites of the second group contain accessory amounts of REE minerals; the third group is peculiar in the abundance of late carbonatites, where REE carbonates are frequently major minerals. Thus, the greater the volume of REE minerals in carbonatites of the complex, the lower the δ34S value in sulfides from its carbonatites and associated rocks. For the first time in the KAP, the sulfur isotopic composition of associated baryte–pyrite pairs was studied in the Sallanlatva carbonatites. The sulfur isotopic characteristics are shown to correspond to the final low-temperature (250–350°C) stage of carbonatite evolution in oxidized conditions, which satisfies the parameters of baryte crystallization. Since the studied samples of the Sallanlatva carbonatites are explosive breccias, the oxidized composition of fluids may indicate their phreatomagmatic nature, i.e., formation due to the interaction of intruded hot matter (melt/fluid) with meteoric waters. [ABSTRACT FROM AUTHOR]

The article discusses the application lifecycle of a new management system for IBR-2 users. The neutron source IBR-2 reactor at the Frank Laboratory of Neutron Physics at JINR is a unique instrument for investigating the neutron's fundamental properties and research in condensed matter physics. Users worldwide are presented with a new convenient service—the IBR-2 User Program, which allows you to perform an experiment with your own studying sample using one of the IBR-2 instruments (i.e., spectrometers, diffractometers or others). A very important part of the User Program at FLNP is to determine a system for proposal submission and evaluation as well as online control of experiment implementation. [ABSTRACT FROM AUTHOR]

The discharge of the zinc–perchloric acid–lead dioxide electrochemical system at temperatures from –50 to +50°C was studied. Zinc coatings, including those subjected to chromate passivation, can be used as anode materials for fast-activated reserve chemical power sources. The tests of pilot batches confirmed that the power sources met the activation time requirements (no more than 50 ms). The power sources of the given system are characterized by increased discharge voltage (the maximum voltage of one cell is 2.12–2.44 V) compared with that of the lead–perchloric acid–lead dioxide system (1.50–1.86 V). The disadvantages of the zinc–perchloric acid–lead dioxide system were revealed: instability of discharge characteristics and possible cell polarity reversal as a result of side reactions, which may have a significant negative impact on the reliability of reserve power sources. [ABSTRACT FROM AUTHOR]

A universal technique is developed for the detection of high harmonics generated by relativistic and subrelativistic laser pulses irradiating a solid target. Features in the spectra of harmonics generated by a parametric mid-IR laser system and near-IR laser system based on chirped pulse amplification were analyzed. Experimental spectra of harmonics in the range up to 35 nm were recorded. They can be used as a source of coherent radiation in the extreme UV region. [ABSTRACT FROM AUTHOR]

Polymer materials were created on the basis of an unsaturated polyketone, and their mechanical and sorption characteristics were determined. [ABSTRACT FROM AUTHOR]

The electrophysical properties of ionic liquids with different chemical structures of their anions and fillers, as well as a polymer material containing ionic liquids, were studied. [ABSTRACT FROM AUTHOR]

An oil-resistant liner composition was created on the basis of an unsaturated polyketone and a chlorine-containing epoxy oligomer for binding a highly filled polymer composite containing transformer oil plasticized isoprene rubber with disperse fillers on a rubberized fabric substrate. The rheological properties of the liner composition were studied. For the liner composition, mechanical properties were determined at different temperatures alongside with its vitrification temperature and swelling in transformer oil. [ABSTRACT FROM AUTHOR]

Evaluating the liquefaction capacity of saturated loose sandy and clayey soils is an important task to be completed in the course of implementing new construction projects in seismic areas. This article addresses the main characteristics and input parameters of three soil models, including HS small, UBC3D-PLM, and PM4Silt. The behavior of the "soil base–pile foundation–structure" system is examined by using these models to simulate the soil behavior during an earthquake. The results demonstrate the main differences between these models and draw attention to the importance of the choice of a soil model for seismic analysis, particularly when soil liquefaction is considered. [ABSTRACT FROM AUTHOR]

Electrochemical machining (ECM) of the inner surface of cylindrical workpiece (WP) with an eccentric rotating cylinder tool-electrode (TE) is studied theoretically using a new mathematical model. The proposed model uses a moving coordinate system bound to the rotating WP. In this case, only the variation in the position of TE center during its orbital movement is taken into account. In addition, for convenient solution and analysis of results, the mathematical model was presented in the dimensionless form in order to reduce the number of parameters. The local one-dimensional approximation is used to calculate the distribution of the current density. It enables determining the distribution of the current density not from the solution of Laplace's equation, but using a simple analytical equation. Three dimensionless parameters are proposed to characterize the properties of the workpiece material, the electrolyte solution and working conditions, and also the dimensions of the electrodes and the rate of their relative motion. These parameters are used in the numerical solution and analysis of the results. The obtained relationship between the accuracy and productivity of ECM with an eccentric rotating TE can be used to optimize the process. The error in the shape of workpiece surface is analyzed within the proposed model. The relation between the error of machining and the minimum interelectrode gap is revealed. A two-stage ECM scheme is proposed to reduce the shape error. [ABSTRACT FROM AUTHOR]

The electrical properties of Pd/InP Schottky diodes and Pd-layers deposited on glass substrate by thermal evaporation in vacuum, and placed in hydrogen medium containing 10–100 vol % of hydrogen, were studied. The current generation in Pd/InP Schottky diodes, as well as the decrease in resistance of Pd layers were observed in hydrogen medium. It is proposed that the current generation in the structures under study is due to free electrons as result of hydrogen atoms ionization. The current induced by these electrons exists in electric circuit until hydrogen is present in the environment. It is shown that the hydrogen current generators can be created based on the Pd/InP diode structure. [ABSTRACT FROM AUTHOR]

In this paper, we examine differential equations with nonclassical initial conditions and noninvertible operators in their principal parts. We find necessary and sufficient conditions for the existence of unbounded solutions with a pole of order p at points where the operator in the principal part of the differential equation is noninvertible. Based on the alternative Lyapunov–Schmidt method and Laurent expansions, we propose a two-stage method for constructing expansion coefficients of the solution in a neighborhood of a pole. We develop the techniques of skeleton chains of linear operators in Banach spaces and discuss its applications to the statement of initial conditions for differential equations. The results obtained develop the theory of degenerate differential equations. Illustrative examples are given. [ABSTRACT FROM AUTHOR]

The problem of parametric identification of some nonlinear models of fast hydrogen permeability of alloys for membrane technologies for the release of high-purity hydrogen (on the example of alloy B1) is solved. Not only diffusion in the bulk of the material is taken into account, but also physical and chemical processes on the surface: adsorption, desorption and rapid dissolution. The mathematical software and the results of numerical simulation for a three-stage breakthrough experiment with vacuum pumping at the membrane outlet from the structural material under study are presented. The influence of the accumulation of atomic hydrogen on the surface has been studied. [ABSTRACT FROM AUTHOR]

The synthesis of (p)ppGpp alarmones plays a vital role in the regulation of metabolism suppression, growth rate control, virulence, bacterial persistence, and biofilm formation. The (p)ppGpp alarmones are synthesized by proteins of the RelA/SpoT homolog (RSH) superfamily, including long bifunctional RSH proteins and small alarmone synthetases. Here, we investigated enzyme kinetics and dose-dependent enzyme inhibition to elucidate the mechanism of 4-(4,7-dimethyl-1,2,3,4-tetrahydronaphthalen-1-yl)pentanoic acid (DMNP) action on the (p)ppGpp synthetases RelMsm and RelZ from Mycolicibacterium smegmatis and RelMtb from Mycobacterium tuberculosis. DMNP was found to inhibit the activity of RelMtb. According to the enzyme kinetics analysis, DMNP acts as a noncompetitive inhibitor of RelMsm and RelZ. Based on the results of molecular docking, the DMNP-binding site is located in the proximity of the synthetase domain active site. This study might help in the development of alarmone synthetase inhibitors, which includes relacin and its derivatives, as well as DMNP – a synthetic analog of the marine coral metabolite erogorgiaene. Unlike conventional antibiotics, alarmone synthetase inhibitors target metabolic pathways linked to the bacterial stringent response. Although these pathways are not essential for bacteria, they regulate the development of adaptation mechanisms. Combining conventional antibiotics that target actively growing cells with compounds that impede bacterial adaptation may address challenges associated with antimicrobial resistance and bacterial persistence. [ABSTRACT FROM AUTHOR]

Anhydrous dimolybdenum perfluorotetrabenzoate Мо2(ООСС6F5)4 (I) and silver perfluorocyclohexanoate AgOOCC6F11 (II) are synthesized for the first time. Complex I is synthesized by the transcarboxylation of dimolybdenum tetraacetate with pentafluorobenzoic acid. Compound II is synthesized from freshly prepared silver oxide and perfluorocyclohexanoic acid. The evaporation of the complexes is studied by the Knudsen method with mass spectral analysis of the gas phase. The sublimation of Мо2(ООСС6F5)4 is congruent. The enthalpy of sublimation and the equation of the temperature dependence of the vapor pressure are found. The evaporation of AgOOCC6F11 is accompanied by the complete thermal decomposition with the formation of Ag(s) and mainly С6F12, С6F10, and CO2 molecules. The standard enthalpies of thermal decomposition ( (5) = 439.5 ± 16.4 kJ/mol, (6) = 325.2 ± 14.0 kJ/mol) and formation of the silver complex ( (AgOOCC6F11, c) = –2751.0 ± 24.4 kJ/mol) are determined. [ABSTRACT FROM AUTHOR]

New cadmium 2,3,4,5-tetrafluorobenzoate (6HTfb) and 2,3,5,6-tetrafluorobenzoate (4Htfb) complexes, [Cd(6HTfb)(H2O)3]n·(6HTfb)·2nH2O (I), [Cd3(Phen)2(6HTfb)6] (II, Phen = 1,10-phenanthroline), [Cd2(Phen)2(4Htfb)4]n·2nH2O (III), and [Cd(Phen)2(4Htfb)2] (IV), were synthesized. Analysis of the obtained results and published data demonstrated that a decrease in the number of fluorine substituents is unfavorable for the formation of coordination polymers comprising stacked alternating fluorinated and non-fluorinated aromatic moieties. In the case of 2,4,5-trifluorobenzoate complex, a typical trivial structure of the binuclear cadmium complex with ligand-shielded metal core is formed. The synthesis of 2,3,4,5- and 2,3,5,6-tetrafluorobenzoate complexes produced an intermediate situation and demonstrated that the structure of complex formation products is affected by not only the number, but also the positions of fluorine substituents. Using quantum chemical calculations, it was shown that the formation of coordination polymers requires a molecular precursor with a Chinese lantern structure stable in solutions, while the formation of unusual flattened binuclear complexes with additionally coordinated water molecules requires doubly bridged binuclear complexes able to switch to a conformation with exposed coordinatively unsaturated metal centers. [ABSTRACT FROM AUTHOR]

Crystallization processes of amorphous Al–Ni–Co-REM (REM = Nd, Sm, Gd, Tb, Yb) alloys with different ratios of transition metals are investigated. The activation energies for various stages of crystallization are calculated from experimental data. It is shown that the alloys with a high cobalt content are more thermally stable and preferable for further practical use. [ABSTRACT FROM AUTHOR]

The paper presents the results of experimental measurements of thermoelectromotive force and electrical conductivity of animal blood samples and Ringer's medical solution, which are similar in their properties and chemical composition to human blood. The influence of the contributions of the ionic component and the contribution of blood corpuscles on the value of the thermoelectromotive force coefficient is analyzed. The effect of dilution with distilled water on thermo electric properties and electrical conductivity of blood has been studied. The influence of the ionic composition of a model medical Ringer's solution on the coefficient of thermo electromotive force is analyzed. The experimental results show that the co efficient of thermoelectromotive force of the blood samples under study is determined to a greater extent by the colloidal component of the shaped elements than by the contribution of the ionic subsystem. The results obtained indicate that thermoelectric phenomena in biological fluids can affect the activation of bio chemical processes in the body of animals. [ABSTRACT FROM AUTHOR]

The properties of oligomeric unsaturated polyketones with different oxygen contents have been studied. The compatibility of unsaturated polyketones with epoxy oligomers has been studied. It has been shown that curing of unsaturated polyketones is possible using quinol ether and dinitrile oxides. Liner compositions based on unsaturated polyketones and epoxy oligomers have been produced for bonding highly filled polymer compositions with a rigid multilayer substrate. The physicochemical and physical–mechanical characteristics of the produced polymer materials have been studied. [ABSTRACT FROM AUTHOR]

This work considers issues related to modern geometrical ideas about the structuring at phase transitions in solids and liquids. [ABSTRACT FROM AUTHOR]

Terahertz pulse generation from multiterawatt laser surface plasma near thick solid targets and thin foils has been studied. Pulses with energies up to 7 μJ were detected in the spectral region <3 THz in the direction of specular reflection from the surface of the CaF2 target. The dependence of the terahertz pulse energy on the laser pulse intensity can be approximated by the power function . For a fixed laser pulse duration and variable energy the power index lies in the range , while for a fixed energy and variable duration . [ABSTRACT FROM AUTHOR]

The results of numerical simulation of the optical properties of a one-dimensional (1D) photonic crystal with a defect based on semiconductor-dielectric layers in the near-IR range are presented. The simulations used layers of silicon and silicon dioxide with optical thicknesses 3λ/4, λ/4 and 10λ/4. The influence of radiation incident angle on the spectral position of the defect's guidance band has been studied. It is shown that the sensitivity to the rotation angle lies within the limits of 6–20 nm/deg and 1.7–5.5 dB/deg, depending on the geometry of the sensor and the measurement method. This makes these photonic crystals promising for use in the rotation angle sensors as a sensitive element. [ABSTRACT FROM AUTHOR]

The magnetic system of an open trap usually includes expansion sections located between high-field magnetic mirrors and end surfaces that receive plasma. In the GOL-NB device, an arc plasma gun is located in one of the expanders, which creates a low-temperature starting plasma in the confinement area. The parameters of the surface plasma sheath affect the electrical connection of the confinement area with the walls and, thereby, affect the contribution of the line-tying effect to the plasma stability and the longitudinal energy losses from the trap. The experiments with additional hydrogen injection into the plasma gun were carried out at GOL-NB. We observed a radiating plasma formation detached from the surface, which visually corresponds to that in radiating divertors in tokamaks. In both standard and detached modes, decaying plasma existed near the receiving electrodes during the entire observation time after the discharge current was terminated. In the central trap of GOL-NB, some structures in the Fourier spectrogram of magnetic fluctuations manifest earlier in the detachment mode than in the standard mode and have lower frequencies. We associate these structures with the onset of interchange-like modes due to the loss of plasma stabilization by the line-tying to the conducting ends. The observed plasma response to the additional gas supply confirmed our understanding of the line-tying effect as the main factor stabilizing the plasma core in the initial phase of density accumulation in the central trap. [ABSTRACT FROM AUTHOR]

We report a synthesis of a series of molecular compounds and coordination polymers of Zn2+, Mn2+ Cd2+, Eu3+, and Tb3+ with 4-allyl-2,3,5,6-tetrafluorobenzoic acid (4-Afb) anions and 1,10-phenanthroline with compositions [Zn(H2O)(phen)(4-Afb)2] (1), [Mn(H2O)(phen)(4-Afb)2]n·nH2O (2), [Cd(H2O)(phen)(4-Afb)2]n (3), [Cd(phen)(4-Afb)2]n (4), [Ln2(phen)2(4-Afb)6] (Ln = Eu 5Eu; Tb 5Tb). It is shown that the obtained cadmium coordination polymers have various compositions and structures, depending on crystallization conditions. The prepared compounds are characterized by single-crystal XRD, powder XRD, IR spectroscopy, and CHN analysis. Noncovalent interactions are analyzed using the Hirshfeld surface analysis. It is determined that the crystal packings is mainly stabilized by π⋯π, C–H⋯F, and C–F⋯π interactions. The photoluminescent properties of the 5Eu and 5Tb complexes are studied. It is shown that the structure-forming effects of non-covalent "arene–perfluoroarene" interactions can be possibly used for preorganizing reactive functional groups in the crystal. [ABSTRACT FROM AUTHOR]

The reaction of the 2,3,4,5-tetrafluorobenzoate (6H-tfb) compounds [Cd(H2O)4-(6H-tfb)]n • n(6H-tfb) (1) and [Tb(H2O)2(6H-tfb)3]n (2) with 1,10-phenanthroline (phen) affords the heterometallic complex [Cd2Tb2(phen)2(6H-tfb)10] (3). The 2,3,5,6-tetra-fluorobenzoate (4H-tfb) complexes [Cd2Tb2(phen)4(4H-tfb)10]·4MeCN (4) and [Cd2Tb2(phen)2(4H-tfb)10] • 4 C6H6 (5) were obtained by reacting cadmium and terbium nitrates with K(4H-tfb) and phen. Depending on the crystallization medium, compounds of different compositions and structures are formed. The use of two isomers of tetrafluorobenzoic acid allowed the analysis of the effect of the substituent position on the structure and the crystal packing of the resulting complexes. Unlike {CdLn} pentafluorobenzoate compounds, new complexes 3–5 do not have a polymer structure, which may be evidence of weaker intermolecular interactions of these isomeric tetrafluorobenzoate anions compared to compounds containing pentafluorobenzoate anions. The synthesized compounds were characterized by X-ray diffraction, IR spectroscopy, and elemental analysis. Noncovalent interactions were investigated using the Hirshfeld surface analysis. The main contribution to the stabilization of the crystal packing is made by π⋯π, C−H⋯F, and C−F⋯π interactions. For complex 2, the luminescence quantum yield and the excited state lifetime are 45% and 1.95 ms, respectively, which are comparable with the corresponding values for heterometallic phenanthroline-containing pentafluorobenzoate complexes. [ABSTRACT FROM AUTHOR]

Dimolybdenum tetratrimethylacetate (tetrapivalate) and tetratrifluoroacetate are synthesized, and their evaporation is studied by the Knudsen effusion method with mass spectral analysis of the gas phase. The standard enthalpies of formation of crystalline and gaseous Мо2(СF3COO)4 are estimated for the first time by the study of dissociative ionization. The solid-phase reactions of silver pivalate (CН3)3СCOOAg with molybdenum are studied by thermography (TG), differential scanning calorimetry (DSC), and mass spectrometry. The reaction in a temperature range of 410–480 K affords molybdenum oxopivalate МоО2Piv2. The obtained experimental data make it possible to estimate the standard enthalpy of formation of this compound: (МоО2Рiv2, cr) = –1476 kJ/mol. [ABSTRACT FROM AUTHOR]

In this paper, we consider issues of the kinetic theory of strength and the effect of temperature and force factors on the damage accumulation in materials. Phenomenological models of the formation and propagation of defects structures determine the strength, anticorrosion, tribological properties of materials, and the nature manifestations of destruction processes during operation. The selection and verification of a material behavior model makes it possible to apply reasonably methods to improve their performance and protect against corrosion. [ABSTRACT FROM AUTHOR]

The results of experimental studies of the possibility of using strain gauges under local pulsed thermal loading to evaluate the tension of the press connections of bearing rings with shafts are presented. Samples of press-fit joints in the range from 38 to 118 μm were prepared. As a result of the study of the patterns of heat flow propagation in bearing rings and tension samples by contact method and by means of thermal imaging, the possibility of separating strains associated with the influence of temperature on the strain measurement area and the temperature gradient in the heating area is shown. The methods of inspecting a press joint exposed to a heater ring with a heat power capacity of 80 kJ and a temperature of 200°C and measuring the strains of the ring and shaft by an opto-polarizing sensor with a base of 60 mm and a resolution of relative deformation units have been experimentally implemented. A correlation has been established between the time of reaching the maximum of local strains in the shaft with the tightness of the press joints and of the sign of strains in the bearing ring with a press fit leak with the gap between the ring and the shaft. [ABSTRACT FROM AUTHOR]

Abstract—An analysis of changes in the role of mammals in the infection of humans with hydrophobia in Russia for the period 1534–2017 is presented. Human deaths when dealing with dogs have continually been recorded since the 16th century. The share of dogs in human hydrophobia infection reached 85% from the end of the 19th century to the middle of the 20th century. In the 1960s and 1970s, it decreased to 30–35%, but in the early 21st century, it increased again to 43%. The role of cats in infecting humans has been reliably traced since the late 19th century, and it has increased from 2 to 18% over the last 130 years. The epidemic value of foxes is cyclical. In the late 18th century, fox rabies in Russia was not known. People died from hydrophobia after fox bites in the early 19th century, but since 1825 cases of human hydrophobia due to contacts with foxes were no more recorded. Foxes again started infecting people only from the 1940s. In some years from the 1970s to the 1990s, foxes were the source of hydrophobia in 50–52% cases. In the 21st century, the role of foxes in human infection has decreased to 16%, but the value of that predator in animal infection increased to almost 50%. The wolf has infected people throughout the historical record. Before World War II, the epidemic value of the wolf reached 19%, but since the second half of the 20th century and in the 21st century, the death of people caused by wolf bites has varied within 2–7% cases. The raccoon dog started infecting people after World War II (0.4%). Its epidemic role has slowly increased and reached 11% in the 21st century. The corsak, the badger, the marten, the ferret, and the Arctic Fox rarely infect people, but they have participated in the epidemic process for at least 50 years, while the Arctic Fox has for 100 years. Over the territory of Russia, only two cases of human death have been recorded from hydrophobia after a bat bite, one in 1985 and the other in 2008. Cattle have infected humans throughout the observable past five centuries, but not too often, 0.3–2% cases. Small livestock, horses, and pigs have been extremely rare as an epidemic danger for at least the last 130 years. In Russia, people have never been infected with rabies received from insectivores, while that obtained from rodents has been recorded only three times: two from gophers and one from a squirrel. [ABSTRACT FROM AUTHOR]

Computer simulation of longitudinal rolling is performed for different combinations of the diameters of the upper and lower rolls: 600–600, 590–600, 570–600, and 300–600 mm. The rolling for each variant of combinations of working roll diameters has been carried out in three passes (the initial strip thickness is 2 mm; the gap between the rolls is 1.4 mm in the first pass, 0.98 mm in the second pass, and 0.66 mm in the third pass. The methods have been proposed for determining the lengths of the arc of contact and of the actual deformation site, and the lengths of external zones have been estimated. [ABSTRACT FROM AUTHOR]

The results of experimental study of morphology of silver nanostructures, which appear during thermal destruction of polyvinyl alcohol film with silver nitrate are presented. It is shown that during the increase of silver nitrate concentration the maximum size of the formed particles increases from tens of nanometers up to 2 μm, and their shape transforms from spherical to irregular. The growth of silver nanoparticles occurs at the expense of small silver nanoparticles migration on a substrate surface, their gathering near the large nanoparticles and confluence of small nanoparticles with larger ones. [ABSTRACT FROM AUTHOR]

It is shown that the irradiation by focused electron beam with electron energy of 10 keV of two-layer amorphous silicon–carbon films 60 nm thick results in films partial crystallization. Moreover, in the irradiated zone the layer of crystalline silicon carbide with luminescent properties is formed. The observed effects are confirmed by methods of Raman spectroscopy and by luminescence spectra. [ABSTRACT FROM AUTHOR]