Mathematical Model of the Stick-Slip Effect for Describing the "Drumbeat" Seismic Regime During the Eruption of the Kizimen Volcano in Kamchatka

During the eruption of the Kizimen volcano in 2010-2013. There was a uniform squeezing of the viscous lava flow. Simultaneously with its movement, earthquakes with an unusual quasi-periodicity were recorded, the "drumbeats" mode. In this work, we show that these earthquakes were generated by the movement of the flow front, which was observed for the first time in the practice of volcanological research. We represent the movement of the flow as an intermittent slip with the inclusion of the "stick-slip" mechanism with the initiation of a self-oscillating process. The plausibility of the phenomenological model at the qualitative level is confirmed by the mathematical model of a fractional nonlinear oscillator

Globalization of culture and higher education by means of academic mobility

The relevance of the research problem is caused by the worldwide process of globalization that affected different aspects of the human life including culture and education. The aim of this article is to confirm the hypothesis that academic mobility may serve as a means of globalization of culture and higher education and carry in itself a certain social demand. The main approach of the research is the comparative approach, which allowed us to compare different approaches to the definitions of the concepts “culture”, “globalization”, “internationalization” and “academic mobility”. This research reveals the interconnection between culture and education. It proves that academic mobility of students may serve as a means of globalization of culture and education. The content of the article may be useful for the teachers of the Cultural Studies, Anthropology, and Education in the institutions of higher education.peer-reviewe

Internal and external factors promoting the Diels-Alder reaction

The basic chemical and physical factors determining the rate and equilibrium of the Diels-Alder reaction under standard and high hydrostatic pressures were considered. The search for favorable conditions for this process makes it possible to extend the range of potential reactants and to perform reactions that earlier considered to be forbidden. © 2013 Springer Science+Business Media New York

Energy and volume activation parameters of the retro-Diels-Alder reaction in different solvents

The temperature and pressure effects on the decay rate of an adduct obtained from 9-chloroanthracene and tetracyanoethene by a Diels-Alder reaction were studied. The rate constants (298.2 K) and the enthalpies, entropies, and volumes of activation were determined for the retro-Diels-Alder reaction in different solvents. The data obtained confirm a possible decrease in the molar volume of the solvated adduct upon partial bond cleavage on the way to the transition state. The reversal of the sign in front of the activation volume cannot be indicative of a changed reaction mechanism. © 2009 Springer Science+Business Media, Inc

Compressibility of liquids. Rule of noncrossing V-P curvatures

Weight analysis of the liquid introduced into the stainless steel bomb under pressures up to 1 kbar in the temperature range of 20-50°C at the interval of 10°C was performed for 1,4-dioxane, acetonitrile, toluene, ethyl acetate, chlorobenzene, and n-hexane. The coefficients of the Tait equation were determined for all of the solvents at each temperature. There was a clear linear relation between the tangent bulk modulus (1/βT) at atmospheric pressure (1 bar) and the secant bulk modulus at 1 kbar; 1/βT = 0.9865 × (1000 V0/ΔV 1kbar) - 4559 was found at a wide range of temperatures for different liquids, including glycerol and even mercury. This represents the rule of noncrossing P-V curvatures for the liquids. Using the correlation, it is possible to predict the coefficients (C, B) of the Tait equation from the experimental data of βT at 1 bar or, on the other hand, to calculate the value of βT from experimental compression at high pressures. © 2008 American Chemical Society

Dynamics of alcohol consumption by the population in the period before and during the Covid-19 pandemic in the Russian Federation

The purpose of the study is to analyze the dynamics of alcohol consumption by the population in the period before and during the COVID-19 pandemic in the Russian Federation.Цель исследования – анализ динамики потребления алкоголя населением в период до и во время пандемии COVID-19 в РФ

Solvent effect on the enthalpy of solution and partial molar volume of the ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate

Enthalpies of solution and partial molar volumes of the ionic liquid 1-butyl-3- methylimidazolium tetrafluoroborate were determined in 15 solvents of different polarity. Very large differences of the enthalpies of solution (Δ ΔsolHIL = 38.9 kJ·mol -1) and partial molar volumes (ΔVIL = 43 cm 3·mol -1) are nearly the same as observed for lithium perchlorate solutions. These results clearly indicate that the low values of the macroscopic polarity parameters of [bmim]BF 4 do not correspond with the large differences of the intermolecular interactions in IL solutions. The values of the partial molar volume of the cation, V [bmim]+, were estimated for the first time. The changes of the partial molar volumes, V IL, reflect mainly the changes of anion volume, V BF4. The rate of the Diels-Alder reaction of 9,10- dimethylanthracene with maleic anhydride in the [bmim]BF 4 medium was nearly the same as in common molecular solvents. © Springer Science+Business Media, LLC 2012

Enthalpies of solution and partial molar volumes of magnesium perchlorate in alcohols and salt effect of acceleration of the Diels-Alder reaction

Densities and enthalpies of solution at 25°C were measured for dilute solutions of magnesium perchlorate (MP) in some alcohols using the Anton Paar DSA 5000M vibrating tube densimeter and differential calorimetric measurements. In all studied solvents the solution of MP was highly exothermic and large solvent volume contraction was observed. Maximum effect was obtained in methanol and ethanol solutions. Acceleration effect of the Diels-Alder reaction of 9,10-dimethylanthracene with acrylonitrile (in medium of acrylonitrile) in the presence of salts LiClO4, Mg(ClO4)2 and GaCl3 was as 18:160:59,000. © 2011 Elsevier B.V

Anomalies in the change of volumetric parameters of the Diels-Alder reaction in solution

In this article negative values of the activation volume in retro-Diels-Alder reactions are interpreted in terms of the different possibilities of penetration of the solvent molecules into the sterically branched structures of the adduct and activated complex. Empty spaces, inaccessible to penetration of solvent molecules, lead to increases of the molar volume of the screened adducts in solution and, consequently, to a less negative value of the Diels-Alder reaction volume. The values of partial molar volumes of anthracene, maleic anhydride and the adducts cyclopentadiene-maleic anhydride, anthracene-maleic anhydride and anthracene-tetracyanoethylene, in several solvents, were calculated from the solution density data. © Springer Science+Business Media, LLC 2012

Solvent effect on the heat of solution and partial molar volume of magnesium perchlorate

For magnesium perchlorate (MP), the solvent effect on the heat of solution and partial molar volumes (PMV) at 25 °C was studied. Since the complete dissociation of magnesium perchlorate is more difficult to achieve as compared with lithium perchlorate (LP), the concentration dependence of the values of the heat of solution and partial molar volume were noted. Only in highly polar solvents with large donor numbers (DN), such as water, dimethyl sulfoxide, N,N-dimethyl formamide, and formamide, the differential and integral values of the enthalpies of solution were the same in the range of concentrations studied. In all solvents studied, the values of the heat of solution of MP were highly exothermic and exceed that of LP by more than 30 kcal mol-1. The values of the partial molar volume of MP were changed from 82.3 cm3 mol-1 in formamide to -2.4 cm3 mol-1 in acetone, and correlate linearly with that of LP (R=0.975). Taking into account the significant change in the properties of molecules in the solvate shell of cation Mg2+, the large increase in the reactivity of reactants, activated by such interaction with Mg2+ cation is expected. © 2010 John Wiley & Sons, Ltd