Home – Home – Jornals – Contemporary Problems of Ecology 2014 number 1

Modern phylogenies of plague agent Yersinia pestis (Logh.), built with the help of molecular genetic methods, do not provide satisfactory functional adaptation explanation and do not have enough ecological validity. An ecological scenario of the origin of the plague agent was proposed: original pseudotuberculous bacterium Yersinia pseudotuberculosis O:1b had moved to an unoccupied ecological niche (and a new adaptive zone) under ultra-continental climatic conditions of the late Pleistocene (Sartan Ice Age, 22–15 thousand years ago) on the territory of South Siberia and Central Asia. Intervening media, a parasitic system “tarbagan Marmota sibirica – flea Oropsylla silantiewi ” in which the genesis and adaptation of the plague agent had taken place, was characterized. This scenario, based on the main principles of modern evolutionary synthesis, opens the way to ecological-genetic synthesis in regard to the problem of plague origin. It also provides a fine model for developing of the theory of molecular evolution of pathogenic microorganisms.

Vibrio cholerae eltor strains with different epidemic importance isolated from river water in Vladivostok during the cholera outbreak (1999) and in Irkutsk during the disease-free period (2005) were used in the experiment. Biofilm structure consisting of a peripheral part, bundles, polysaccharide matrix, channels and polymorphic vibrios is presented using light and luminescent microscopy. Metachromatic pink colouring of the matrix (crystal-violet, toluidine blue) or fluorescent reddish-orange colour (acridine orange) indicate that acid mucopolysaccharides (glucosamineglucans) are present in its structure. Biofilm of a toxigenic strain is formed much later than the non-toxigenic strain biofilm, and the elements making its structure are more apparent. Viability of V. cholerae cells during the whole experiment (90 days) and preservation of initial pathogenic potential indicate high adaptive properties of V. cholerae eltor that provide its survival and reproduction in surface water reservoirs under favourable ecological conditions (optimum temperature, existence of a chitin-containing substratum, etc.).

Dynamics of reservoire potential (RP) and index of reservoir potential (IRP) of natural hosts of hantaviruses in the ecosystems of Primorskiy Krai was studied (from 2001 to 2010). Long-term average annual IRP for mice of genus Apodemus in the common reservoire potential amounted to 0,83, and IRP for A. peninsuale was 2 times higher than for A. agrarius ( t = 2,636; n = 18; р = 0,017). Predictive indices of a possible spreading of hantavirus infections on the territory of Primorskiy Krai were also denoted.

Since 1997, the English version of the Journal “Thermophysics and Aeromechanics” has been disseminated in other countries by the International Academic Publishing Company "Nauka/Interperiodica”, and since 2006 by the Corporation Springer Science + Business Media (including electronic version). Information about the English versions of all articles published in the journal “T & A” is placed in international databases SCOPUS (from 2006) and Web of Science (since 2008). The impact factor of our Journal is still low (IF ISI 2012 = 0.304), but we believe in its growth.
DOI: 10.1134/S0869864314010016

For the first time, detailed experiments aimed at evaluation of the influence of flat microroughness elements (adhesive tape stickers attached to the streamlined surface) on the mean and pulsation flow characteristics in flat-plate and swept-wing boundary layers were carried out under comparable dimensional conditions. At Mach number М = 2, the sticker shape was found to have almost no influence on the amplitude of mass-flow pulsations in the wake of sticker. The relative receptivity of 3D boundary layer to stationary disturbances was obtained to be approximately 1.5 times higher than the receptivity of 2D boundary layer. It was found that the presence of a sticker at the line of the source of controlled disturbance changes the pulsation spectra in 2D and 3D boundary layers in comparison with unperturbed flow. In the wake behind the center of a sticker, the flow can be most unstable.
DOI: 10.1134/S0869864314010028

The stationary shockwave systems (the sequences of shocks, isentropic expansion and compression waves), which arise at a planar supersonic flow of perfect inviscid gas around the bodies are investigated theoretically. The domains of the existence of shockwave systems under consideration are found analytically and numerically for the model problems of supersonic aerodynamics (the flow around a single plate, the plate with the frontal shield, polygonal profiles), the parameters of systems are determined, which provide the extrema of the force and thermal loadings as well as of the aerodynamic coefficients of streamlined bodies.
DOI: 10.1134/S086986431401003X

A new approach was proposed for simulation of unsteady cavitating flow in the flow passage of a hydraulic power plant. 1D hydro-acoustics equations are solved in the penstock domain. 3D equations of turbulent flow of isothermal compressible liquidvapor mixture are solved in the turbine domain. Cavitation is described by a transfer equation for liquid phase with a source term which is responsible for evaporation and condensation. The developed method was applied for simulation of pulsations in pressure, discharge, and total energy propagating along the flow conduit of the hydraulic power plant. Simulation results are in qualitative and quantitative agreement with experiment. The influence of key physical and numerical parameters like discharge, cavitation number, penstock length, time step, and vapor density on simulation results was studied.
DOI: 10.1134/S0869864314010041

It is suggested to use the method of experimental investigation of temperature conditions at the spacecraft with application of their reduced thermal models based on the similarity criteria formulated under the assumption of the mathematical nodal model of the studied object. Usually thermal-vacuum experiments with full-size object have tight time constraints due to a significant cost. However, on the basis of result of this limited experiment we can specify the parameters of the scale model developed using the nodal mathematical model. This correction ensures the compliance between the results of full-size and scale experiments. After that the scale thermal experiment can supplement the full-scale experiment due to investigation of thermal conditions, which cannot be reproduced experimentally in the full-scale experiment because of the limited resources. The suggested method will significantly expand the possibility to get reliable experimental data about the temperature modes of space objects without a considerable increase in costs.
DOI: 10.1134/S0869864314010053

The mathematical model for determination of boiling expectation time and total local evaporation in the falling wavy liquid films at unsteady heat release has been developed. Numerical simulation of the process of wave formation in the falling films of liquid nitrogen has been carried out. Dependence of boiling expectation time on heat flux density under the conditions of graduated heat load increase has been calculated. Satisfactory agreement between the results of numerical simulations and experimental data is shown.
DOI: 10.1134/S0869864314010065

The present numerical analysis addresses free convection flow of a viscous incompressible fluid along an inclined semi-infinite flat plate considering the variation of viscosity and thermal diffusivity with temperature. The governing equations are developed with the corresponding boundary conditions are transformed to non-dimensional form using the appropriate dimensionless quantities. Due to complexity in the transformed governing equations, analytical solution will fail to produce a solution. Hence, most efficient and unconditionally stable implicit finite difference method of Crank—Nicolson scheme has been used to solve the governing equations. Numerical results are obtained for different values of the viscosity, thermal conductivity, inclination angle, Grashof number, and Prandtl number. The overall investigation of the variation of velocity, temperature, shearing stress and Nusselt number are presented graphically. To examine the accuracy of the present approximate results, the present results are compared with the available results.
DOI: 10.1134/S0869864314010077

The heat transfer and air flow around an unconfined heated rotating circular cylinder is investigated numerically for varying rotation rates (α = 0–6) in the Reynolds number range of 20–200. The numerical calculations are carried out by using a finite volume method based commercial computational fluid dynamics solver FLUENT. The successive changes in the flow pattern are studied as a function of the rotation rate. Suppression of vortex shedding occurs as the rotation rate increases (α > 2). A second kind of instability appears for higher rotation speed where a series of counter-clockwise vortices is shed in the upper shear layer. The rotation attenuates the secondary instability and increases the critical Reynolds number for the appearance of this instability. Besides, time-averaged (lift and drag coefficients and Nusselt number) results are obtained and compared with the literature data. A good agreement has been obtained for both the local and averaged values.
DOI: 10.1134/S0869864314010089

The article presents the results of investigation of thermal expansion of 16Kh12V2FTaR steel in the temperature range 20–1000 ºС. Measurements were carried out by dilatometric method with the error (1.5–2)×10⁻⁷ K⁻¹. The temperature dependences of thermal coefficient of linear expansion of steel have been obtained in ferrite-martensite and ferrite-perlite states, and reference tables have been calculated. Influence of samples cooling rate on martensite phase formation is shown.
DOI: 10.1134/S0869864314010090

This paper presents a study of supersonic jets formed by approaches that are new for cold spray technique: the main flow is swirled, the nozzles with permeable profiles and with exit slots on the supersonic section are engineered. The flow swirling achieved in the nozzle prechamber retains downstream to substrate surface. The system of vortices created within the permeable nozzles changes the shock wave features of the overexpanded jet and the geometry of the bow shock wave ahead of the substrate surface. These new features of flow may affect particle motion and particle-substrate interaction under the conditions of cold spray process; this offers tools for obtaining the necessary shape of a spray spot.
DOI: 10.1134/S0869864314010107

Thermodynamic analysis (TERRA program) of synthesis, heating, and melting of stoichiometric glass CaSiO₃•SiO₂ has been carried out. Chemically pure substances silica and lime are subjected to exothermic reaction with further external heating and melting. Wollastonite is synthesized, the chemical reaction generates heat Q_chr = −505.3 kJ/kg, and temperature increases Т = 820 K. When Т_melt = 1812–1814 K, wollastonite melts, and a mixture of liquid wollastonite and condensed silica is formed. At Т_melt = 1995–1997 K, silica melts, and stoichiometric glass (CaSiO₃•SiO₂) is formed. Evolutions of temperature and melting of wollastonite and silica have been studied by detailed step-by-step thermodynamic calculation (ΔТ = 0.1 K).
DOI: 10.1134/S0869864314010119

A non-stationary three-dimensional mathematical model of the electric arc of constant current in the approximation of a partial local thermodynamic equilibrium of plasma is presented. For the purpose of testing the model and computer code a computation of the isothermal laminar viscous fluid flow past a circular cylinder (the testing of the dynamic part of the system of equations) and a computation of the axisymmetric electric arc with a reduced anode attachment have been done. A fair agreement of numerical results with experimental data points overall to the correctness of the mathematical model and the numerical solution technique.
DOI: 10.1134/S0869864314010120

156 man, who were in the surgical department for subsequent reconstructive operation of carotid arteries, were analyzed. Depending on long-term one-year prognosis all patients have been divided into two groups: with unfavorable (93 individuals – 59.6 %) and favorable (63 individuals – 40.4 %) prognosis. It is proved that cardiovascular complications risk such as stroke, transient ischemic attack, myocardial infarction, patients death, and courses deterioration of multifocal atherosclerosis in any arterial region, increase or clinical presentations onset of ischemia in any organ during the first year after surgical procedure increases if there is dyslipidemia in preoperative period, pathologic value of ankle-brachial index (less than 0.9), besides intraoperative characteristic of atherosclerotic plaque (occurrence of intraplaque haemorrhage and extent of atherosclerotic plaque more than 2 cm) in patients. But among this prognostic factors the most important one is the dyslipidemia, herewith statistic regression coefficient of which is 4.64 and Wald index is 43.1. All these data determine maximal prognostic value of dyslipidemia versus other risk factors.

Subject to population screening study the ethnic peculiarities of prevalence rate of ischemic heart disease and its basic risk factors for inhabitants of Yakutia aged 60 years and over were studied as well as the contribution of some risk factors to development of IHD at people of old age residing within the conditions of Extreme North. Epidemiological methods helped to reveal high IHD prevalence rate at Yakut and Caucasian old age population residing in the Republic of Sakha Yakutia (40 and 47 % respectively, р = 0.09) and its risk factors. At advanced-age groups (for Yakut population – 90 years and older, for Caucasians – 80 years and older) the IHD occurs oftener than at the inhabitants of Yakutia aged 60–70 years. Among aged representatives of Yakut nationality compared with people of old age of Caucasian ethnic affiliation the more favourable profile of IHD risk factors was diagnosed. The significant contribution into IHD development at Yakut population is made by HDL hypocholesterolemia and obesity, and at Caucasian – C-creative protein, pulse pressure and obesity.

For inhabitants of Yakutia aged ≥ 60 almost the equally high is the prevalence rate of hypercholesterolemia of low-density lipoprotein cholesterol (hyper- LDL-C) in general population sampling without MS and in cohort with MS – 72.4 % and 77.9 % ( р = 0.248) and has no differences by ethnic factor. Hypertriglyceridemia (hyper-TG) among the inhabitants of the city with MS occurs for every second inhabitant (58.7 %), and these values are three times higher than population ones (17.1 %). Among the aboriginal inhabitants of Yakutia the hyper-TG with MS occurs in 47.1 %, and these numbers are four times higher than the numbers of general sampling (10.5 %). Among the non-aboriginal inhabitants the hyper-TG with MS was found in 2.7 times oftener relatively to the general sampling (64.3 and 23.4 %). Hypocholesterolemia of high-density lipoprotein cholesterol (hypo-HDL-C) with MS (56.7 %) frequency is three times higher than that in general sampling (18.4 %), this concerns samplings of both aboriginal (50 %) and non-aboriginal (60 %) inhabitants.

Red cell distribution width (RDW), a measure of circulating erythrocyte size heterogeneity, is a new predictor of myocardial infarction (MI) prognosis. The aim of this study is to evaluate the associations of RDW with clinical and laboratory parameters and gender characteristics of patients with acute myocardial infarction. A total of 250 patients (208 male and 42 female) with an ST elevation acute MI were examined. The RDW level was measured with an automated complete blood count. It did not differ in levels of RDW between male and female with MI. Series of associations were detected between RDW and carotid atherosclerosis ( r = +0.156, p = 0.013), chronic anemia ( r = +0.155, p = 0.014), with the presence of cancer ( r = +0.178, p = 0.005), pleural effusion ( r = +0.153, p = 0.015), thrombosis of the left ventricle ( r = +0.133, p = 0.036), acute encephalopathy ( r = +0.178, p = 0.005), leukocytes ( r = +0.132, p = 0.037), platelet ( r = +0.195, p = 0.002), and sodium ( r = –0.232, p = 0.006). The most significant association of RDW with pleural effusion was detected according to the results of covariance analysis. This association has reflected influence of inflammation to complications acute MI.

The purpose was to investigate a frequency of hyperuricemia and its relations with risk factors of degenerative pathology at patients who are elder than 60 years. Methods and result. We examined 212 patients with arterial hypertension and degenerative pathology of aortic valve, of which 76 with nonobstructive aortal calcification and 136 patients with aortic valve stenosis. In blood glucose level, lipids, uric acid, TTH and free T4 were defined. A frequency of hyperuricemia was 30.7 %, overt hypothyroidism 11,3 %, high normal TTH level 11.8 %. In women a combination of hyperuricemia and overt hypothyroidism was 39.3 %, in men it was 8.1 %. A negative correlation was found between glucose level and hyperuricemia.

Investigated the effect of diets and dietary energy supply on the state of carbohydrate and fat metabolism and endocrine status in the group of new comers of the Far North. Studies have shown that of the Far North as a carbohydrate, and type of food indigenous inadequate. Ration with the percentage of the main components (prot : fat : carb) 16:40:44 % is optimal in structure and has anti-atherogenic properties, energy value may vary depending on the severity of the labor.

By the beginning of the 21st century, there are more than 25 hypotheses and «theories» of atherosclerosis. 240 factors contributing to the emergence of atherosclerotic changes in the vascular wall have been described. In recent years, a lot of authors are inclined to the view that atherosclerosis is a chronic immune inflammatory process, which proceeds like hypersensitivity reaction of the delayed type. Inflammatory reactions, both during the decompensation of chronic cerebrovascular insufficiency, and atherosclerosis in general, can be caused by persistent infection of brachiocephalic, cerebral and coronary arteries. The aim of this work was to explore and analyze the foreign studies to determine the role of infections in the development of atherosclerotic changes in vessels. It was found that various infectious agents may be involved in the development of atherosclerosis both individually and in combination. Bacteria and viruses can participate in the formation and destabilization of atherosclerotic plaques leading to endothelial damage, launching systemic immune reactions, inducing cell infiltration and production of proinflammatory factors, initiating coagulation in the endothelium. To date there is no consensus about what is the role of infectious pathogens in atherosclerotic inflammation – are they a primary cause or just «bystanders» that potentiate the already started process.

Analytical review of literature provides information about efficacy and safety of percutaneous coronary interventions in the elderly with acute coronary syndrome.

In the axiomatic approach to the derivation of statistical mechanics the theory is based upon the equations of motions of classical mechanics (Hamilton equations). Since these equations are unstable with respect to initial conditions, in the time τ ≈ 10^–12 s they generate chaos in the system of atoms and molecules. This chaos can be described by only probability theory laws. The laws of this theory are introduced into statistical mechanics as the second postulate. However, for both postulates (i.e., Hamilton equations and probability theory laws) to be compatible with each other, about one and a half ten of additional requirements defining in detail the matter model underlying the theory must be imposed on the system. This report analyzes only the restrictions imposed by probability theory. The main of them are: a transition to the thermodynamic limit, the condition of correlation attenuation, and a short-range character of the interaction potential. The matter model formulated based on these restrictions is a continuous medium in which a correlation sphere with a small radius R ≈ 10^–7 cm (physical point) is submerged. It is submerged in an infinite thermostat, the particles of which behave as the ideal gas relative to the particles forming the correlation sphere. Here all macroscopic parameters of matter in this physical point are determined by the state of the correlation sphere. Thus formulated model determines the macro- and microscopic structure of matter, and finally, results in thermodynamic and hydrodynamic equations.

The value and temperature dependence of the Maxwell relaxation time of viscous tensions and the Lagrangian particle radius, which are the main space-time scales in the Lagrange theory of thermal hydrodynamic fluctuations, are discussed. These parameters play the key role in the estimations of the relative value of the collective component of the molecular self-diffusion coefficient. Special attention is paid to the consistency of estimates obtained by different methods.

In the work the character of water clusterization in the whole existence domain of its liquid state is discussed: from supercooled states to the critical point. Conclusions about the cluster composition of liquid water are drawn based on the analysis: 1) of the features of dielectric relaxation; 2) character of the temperature dependence of its static dielectric permittivity, and 3) the value and temperature dependence of different contributions to the heat capacity of the system. It is shown that near the water crystallization point tetramers prevail in its structure, with an increase in the temperature trimers start to play the main role, and near the critical point of water dimers become the major associates. At temperatures near the water crystallization point the obtained results well agree with the data on emission and absorption X-ray spectroscopy.

The Monte Carlo method and parallel computing are used to calculate the thermodynamic properties of water (density, heat capacity, compressibility, thermal expansion coefficient, and static dielectric constant) in a wide range of temperatures (from 70 K to 530 K) at constant (atmospheric) pressure. Four groups of computational experiments are carried out, each for its own model of the water molecule: TIP3P (Jorgensen et al., 1983), SPC/E (Berendsen et al., 1987), TIP4P/2005 (Abascal&Vega, 2005), and TIP5P-E (Rick, 2004). An additional calculation based on the replica exchange method is conducted for the TIP4P/2005 model. A comparison of the calculated properties of water with experimental data suggests that the TIP4P/2005 model can provide highly realistic computer simulation results for water and aqueous solutions.

Two-particle correlation functions describing the simultaneous motion of a pair of molecules initially separated by a given distance R0 are calculated to study collective effects in the diffusive motion of water molecules in molecular dynamics models. Various types of such functions and their dependences on the interaction potential, temperature, and the number of particles in the model are considered. At short times (of the order of ten picoseconds), these functions exhibit irregular behavior depending on R0. The most nontrivial and unexpected result was the detection of correlations in the displacements of pairs of particles that extend for tens of angstroms and last for hundreds of picoseconds. Such correlations are not observed in the random walk models of noninteracting particles. It is suggested that the observed large-scale correlations reveal the vortex-like motions of the molecules.

Computer simulation of liquid argon and water has shown that the structural inhomogeneity pattern visualized by coloring their instantaneous structures according to the volumes of the Voronoi polyhedra is the same for both liquids. The dynamics of argon atoms in the cavity of a clathrate hydrate and in liquid water is considered. The argon atoms included in the network of hydrogen bonds in liquid water are involved in concerted motion. As a result of this concerted motion, the distance between two argon atoms can fluctuate around some value for a fairly long time. The environment of argon atoms in a liquid aqueous solution differs significantly from their environment in clathrate hydrates.

Solvophobic effects strongly influence the thermodynamic properties of solutions and are one of the driving forces of self-assembly processes of supramolecular structures. However, the generally accepted definition and a quantitative measure of these effects have so far been absent. Based on the analysis of a large set of experimental data on the thermodynamic functions of solvation in various systems, we propose a qualitative criterion allowing us to judge about whether the solvophobic effects are manifested in the solution or not, and also a method to determine their contributions to the thermodynamic functions of solvation. A feature of the solvophobic effect is a violation of the linear relationship between the Gibbs free energy and the enthalpy of solvation, which is fulfilled for the solutions of different compounds in many non-associated solvents. It is shown that in self-associated solvents the solvophobic effect is observed for any dissolved compounds, including well soluble ones, resulting in an increase in the Gibbs energy of solvation. Previously proposed solvophobicity parameters are considered and compared with our results.

This paper is a review of our recent computational studies of volumetric characteristics using computer models of dilute solutions. Partial molar volume (PMV) and its components are calculated for simple and complex molecules in water (methane, noble gases, surfactants, polypeptides). Advantages and disadvantages of various computational methods are discussed. It is proposed to use the Voronoi–Delaunay technique to determine the reasonable boundary between a solute molecule and solvent molecules and to identify the PMV components related to the molecule, the boundary layer, and the solvent. It is noted that the observed increase in PMV with temperature for large molecules is due to an increase in the volume of voids in the boundary layer, i.e., due to the “thermal volume”. In this case, the solvent gives a negative contribution to the PMV. In contrast, for simple molecules (methane), the contribution from the solvent is positive and is the main factor in the increase in the PMV, which is associated with a specific change in water structure around a spherical hydrophobic particle outside the boundary layer. For surfactant molecules, the contribution from the solvent changes sign (from negative to positive) with increasing temperature.

Method of classical molecular dynamics simulated series solutions of the ternary system water—lithium nitrate—calcium nitrate . Calculated radial distribution functions for different pairs of atoms , evaluated coordination numbers of cations and analyzed the nature of changes in the composition of the first solvation shells when the ratio of the components in the system being modeled . The article details the first sphere water molecules in solutions of various concentrations. Allocated 8 basic types entourage structure of the water molecule and its main characteristics , evaluated the probability of occurrence of these structures in the ternary system .

A quantitative topological analysis is conducted of the molecular nanostructures of liquid alcohols as a function of temperature. The analysis is necessary to solve the fundamental problem of the theory of solutions: finding the relationship between the macroparameters of liquids and the structure and properties of intermolecular associates. The analysis is performed using the previously proposed MDGT method, which is based on a combination of molecular dynamics calculations and graph theory. The method enables the recognition and saving of all molecular nanostructures observed in each snapshot of the molecular dynamics trajectory, averaging of data for any number of snapshots to present “averaged” concentrations of associates (dimers, trimers, etc.), and determination of the concentrations and characteristics of isomers (e.g., chains, branched chains, rings, etc.), bond lengths, angles, etc. in each group of associates.

The densities r and coefficients of compressibility k = ΔV/V₀ of a binary mixture {ethylene glycol (1) + tert- butanol (2)} in the temperature range of 278.15-323.15 K and pressures of 0.1-100 MPa over the entire range of compositions of liquid phase state are measured. Found that the coefficients of compressibility k of the mixture increase both with an increase in the concentration of tert- butanol and with a rise in temperature and pressure. The excess molar volumes of the mixture, apparent, partial molar volumes, and limiting partial molar volumes of the components are calculated. It is showed that the excess molar volumes of the mixture are negative and decrease when the pressure increases. The excess molar volumes are described by the Redlich–Kister equation. The partial molar volumes of ethylene glycol sharply decrease in the range of high concentrations of tert- butanol. The dependences of partial molar volumes of ethylene glycol are characterized by the presence of a region of temperature inversion. The “negative compressibility” of the limiting partial volumes of ethylene glycol is revealed.

Based on the experimental data, the molar isothermal compressibilities, molar isobaric expansibilities, thermal pressure coefficients, internal pressures of a liquid phase mixture {ethylene glycol (1) + tert-butanol (2)} are calculated for a wide spectrum of compositions in the range of pressures of 0.1-100 MPa and temperatures of 278.15-323.15 K. Shown that the dependences of molar isothermal compressibilities K_T,m , molar isobaric expansibilities E_P,m , and isochoric thermal pressure coefficients b on the mole fraction of tert-butanol in the mixture are characterized by the absence of extrema typical of aqueous systems. The manifestation of negative partial expansibility and negative partial expansibility of ethylene glycol in the mixture is found. The thermal pressure coefficients decrease with an increase in the mole fraction of tert- butanol at all pressures and temperatures. A rise in the pressure increases the thermal pressure coefficient, while a rise in the temperature decreases its value due to a decrease of free space in the mixture. An increase in the concentration of tert- butanol leads to an increase in the negative temperature coefficient of internal pressure ΔP_int/ΔT, which indicates a weakening of intermolecular interaction at these compositions.

The structural and thermodynamic properties are calculated for mixtures of aprotic amides with water and acetonitrile. The simulation approach is used to identify the specific and nonspecific components of the total energy of intermolecular interactions, which are used to calculate the corresponding contributions to the enthalpy of mixing. The negative enthalpies of mixing in the aqueous mixtures are found to be caused not by heterocomponent specific interactions, but by nonspecific ones. The difference in the structural and thermodynamic properties of the aqueous and nonaqueous mixtures of aprotic amides is shown to be largely due to the behavior of the hydrogen bond network of water and the packing of the resulting solutions.

Dispersions of the refractive index are measured in aqueous solutions of potassium halides at different salt concentrations and temperatures of the solutions. The specific effect of anions on the dynamic dielectric permittivity of the solutions is found. A model is proposed to evaluate the character of changes in the dynamic dielectric permittivity of the solutions and effective dynamic polarizabilities of ions in the solutions based on the data about the dispersion of refractive indices. The role of ion sizes and the character of their interaction with a solvent in the manifestation of specific ion effects are discussed.

X-ray diffraction is used to study Al–Si melts with a content of 0 at.%, 6 at.%, 10 at.%, 18 at.%, 21 at.%, 26 at.%, 35 at.%, 60 at.%, 80 at.%, and 100 at.% Si. The structural factors, atomic distribution curves, and parameters characterizing the immediate environment of atoms in the melts are calculated. The results are described using the microheterogeneous melt structure model near the liquidus temperature. According to the model, the melts contain microgroupings with the statistical atomic distribution that are similar in composition to the Al–6%Si melt and liquid silicon microgroupings. High-temperature studies indicate an increase in the structural homogeneity of the melts with increasing temperature due to the progressive metallization of interatomic bonds in the silicon microgroupings.

The kinetics of the formation of Liesegang rings is considered and they are classified. The relationship between the position of the propagating diffusion front and the moments of the formation of Liesegang rings is shown. In order to describe the formation processes of the Liesegang rings a generalized model based on the diffusion equation hierarchy is proposed. The kinetics of changes in the dispersed phase sizes at the initial stage of the formation of Liesegang rings is studied.