of National Academy of Sciences
of Tajikistan

News of the National Academy of Sciences of Tajikistan.
Department of physical, mathematical, chemical, geological and technical sciences

Известия Национальной академии наук Таджикистана. Отделение физико-математических, химических, геологических и технических наук, №2(187), 2022 г.

Article title and abstractPages
Полный текст статьи

M.Sh.Shabozov , Z.Sh.Malakbozov
On the best simultaneous polynomial approximation of functions in the Hardy space
In the paper, exact Jackson-Stechkin type inequalities are found between the best simultaneous polynomial approximations of functions analytic in the unit circle and generalized modulus of continuity of r-th derivatives of functions. For some classes of functions defined the indicated smoothness characteristic, the exact values of the simultaneous approximation of the functions and their intermediate derivatives are calculated. The values of a series of n-widths of the indicated classes of functions are also calculated.

Ключевые слова: best simultaneous approximation; analytical in the function circle; Jackson-Stechkin type inequalities; n-widths.

Полный текст статьи

About automatic recognition on the basis of unigrams of ciphers of author's abstracts on economy
In the work, using the example of a model collection of 20 abstracts on economics, the γ-classifier is configured to automatically identify the cipher of a scientific work based on the frequency of 33 letters of the Russian alphabet. Font recognition accuracy is set to 95%.

Ключевые слова: economics; text; alphabet; frequency; classifier.

Полный текст статьи

M.M.Kabilov , A.S.Barotov
Influence of temperature dependence of transfer coefficients on combustion wave parameters in two models of filtration gas combustion
The main characteristics of the combustion wave of the methane-air mixture are considered within the framework of two mathematical models of the filtration combustion of gases. The influence of the temperature dependence of the transfer coefficients on the characteristics of the stationary wave of the filtration combustion of a methane-air mixture is studied. The wave characteristics are compared within each model, taking into account the temperature dependence of the transfer coefficients and without it, and between the models.

Ключевые слова: wave; combustion; speed; temperature; dependence; methane-air mixture; heat capacity; thermal conductivity.

Полный текст статьи

S.Odinaev , D.A.Abdurasulov , A.A.Аbdurasulov
On the contribution of the near orientation and radial order of molecules to the heat capacity of the isotropic phase of nematic liquid crystals
On the basis of the generalized equilibrium statistical distribution function of non-spherical molecules, the contributions of the short-range radial and orientational order to the determination of the temperature dependence of the heat capacity of the NLC in the isotropic vicinity of the NLC-IL phase transition point are described. The contributions of the thermal motion of molecules, their elastic collisions, the radial and orientational order of molecules, and fluctuations of the orientational order to the temperature dependence of the heat capacity of the isotropic phase of the NLC are determined.

Ключевые слова: distribution function; nematic liquid crystals; heat capacity; radial and orientational order.

Полный текст статьи

Relationship of dielectric and mechanical properties of films based on polymer and liquid crystal
In this article, the structure, mechanical (strength) and electrophysical properties of composite films based on polymer and liquid crystal obtained from solutions in ethyl alcohol are studied. The modifying (plasticizing) effect of nematic liquid crystals (NLC) on the structure of polyvinylbutyral is shown. As a result of the modification, the dielectric and strength properties of the composites deteriorate; the greatest changes in the above indicators are observed at concentrations (35%) of the incorporated NLC.

Ключевые слова: nematic liquid crystal; dielectric constant; dielectric losses; strength properties; composite films; polyvinyl butyral.

Полный текст статьи

The cationic composition of the atmospheric aerosol of the semi-arid zone of Tajikistan
The article presents the results of measuring the cationic composition of atmospheric aerosol (Na, NH, K, Mgand Ca) in the semi-arid zone of Tajikistan, as well as their comparison with other regions of the world. It was found that among the five tested cations, the highest concentration in the semi-arid zone of Tajikistan is for calcium ions. The reason for the high concentration of calcium is the thermal power plant, the plant "Tajikcement" and transport.

Ключевые слова: aerosol; cationic composition; suspended particles.

Полный текст статьи

M.А.Khalikova , H.B.Kabgov , I.F.Rahimov , S.Sh.Safarov
Humic acids as a feed additive in poultry diets
Many studies tested different feed additives, among these additives, humic substances (HS) have been used in livestock and poultry diets. Humic substances commonly present in nature as they are created from the organic matter decomposition, and are normally found in the soil and natural water. Active components of HS consist of humic acids (HA), humus, ulmic acid, fulvic acid, humin and certain microelements. Humic acids is widely used as an alternative growth promoter for antibiotics in improving poultry performance and health. The study showed that the whole broiler chickens increased by 15% when in the diet of poultry, HA was added in the form of a 0.0025% aqueous solution by drinking, and in laying hens, egg production increased by 5.7% and an increase in whole eggs by 0.8% was observed.

Ключевые слова: humic acid; humic substances; broiler chickens; laying hens; weight gain; increased egg production.

Полный текст статьи

Physical and chemical basis of processing nepheline syenites of the Turpi deposit of Tajikistan with a mixture of mineral acids
This article presents the results of the decomposition of nepheline syenites from the Turpi deposit with a mixture of mineral acids (HPO + HNO). The chemical and mineralogical composition of nepheline syenites has been determined. Optimum parameters of ore decomposition with a mixture of mineral acids have been found. The following conditions for the decomposition of nepheline syenites are recommended: burning at 500-600°C, burning duration 1 hour, acid decomposition temperature 98°C for 1 hour, acid concentration HPO- 30%, HNO - 40% and particle size 0.1 mm. With these optimal parameters, the recovery of AlO is 47.51% and FeO - 83.5%. A basic technological scheme for processing nepheline syenites with mixed mineral acids has been developed.

Ключевые слова: nepheline syenites; Turpi; phosphoric acid; nitric acid; optimal conditions; extraction degree; technological scheme; decomposition.

Полный текст статьи

I.B.Hakimov , I.N.Ganiev , Z.R.Obidov , F.A.Rahimov
Kinetic oxidation of Zn22Al alloy, doped with chrome, in the firm condition
The results of studying the kinetics of oxidation of Zn22Al doped with chromium with atmospheric oxygen in the temperature range 523-623 K in the solid state are presented. The kinetic parameters of the high-temperature oxidation of alloys have been determined. It is shown that the addition of the alloying component somewhat reduces the oxidizability of the Zn22Al alloy, and the oxidation products of the alloys are the oxides ZnO, AlO, GrO, and ZnO∙ GrO

Ключевые слова: Zn22Al alloy; chrome; thermo gravimetrical a method; high-temperature oxidation; speed of oxidation; energy of activation.

Полный текст статьи

Thermodynamics of solvation of 1-methyl-2-mercaptoimidazole in a water-ethanol solvent
The method of interfacial distribution was determined by the transfer energy of the transfer of 1-methyl-2-mercaptoimidazole to the water-ethanol solvents at 298 K. The magnitudes of the Gibbs of the transfer (∆G) calculated from the distribution coefficients with an increase in the non-aqueous component are positive values, which indicates that indicates that That in water-alcohol solvents there is no reassembly of 1-methyl-2-mercaptimidazole.

Ключевые слова: 1-methyl-2-mercaptoimidazole; transfer ∆G; thermodynamics; solvation; distribution coefficient.

Полный текст статьи

D.T.Isozoda , O.A.Azizov , I.Mirsaidzoda , A.Badalov
Thermodynamic substantiation of the processes of obtaining borohydrides of group IA elements from local ores in Tajikistan
By chlorination of local boron-containing ores - danburites that the source originated from the Ak-Arkhara, boron chloride was obtained, which was subsequently used for the synthesis of borohydrides elements of group IA of the Table of Chemical Elements. The synthesis was performed by the interaction of boron chloride with binary hydrides of alkali metals in the appropriate organic environment. A systematic analysis of the thermodynamic characteristics of the components system and the process of synthesis of borohydrides of group IA elements was performed. The values of thermodynamic characteristics of some hydride compounds have been determined and/or clarified. Distinguishing features of binary and borohydride compounds of lithium and sodium from elements of the potassium subgroup were demonstrated. The regularity and mathematical models of changes in the thermodynamic characteristics of borohydrides of elements IA within the IA group of the Table of Chemical Elements have been established.

Ключевые слова: Boron Chloride; Synthesis; Borohydrides of group IA Elements; analysis; thermodynamic characteristics; Patterns of change.

Полный текст статьи

Stability of Fe(III) complexes with 1-phenyl-2,3-dimethylpyrazoline-5-tione in 1 mol/l HSO
A potentiometric method using a redox electrode based on 1-phenyl-2,3-dimethylpyrazoline-5-thion and its oxidized form investigated the process of complexation of Fe(III) with 1-phenyl-2,3-dimethylpyrazoline-5-thion (FPt) in a sulfuric acid solution. It is established that, depending on the temperature of the experiment, the value of the formation function (n) for this system varies from 0.1 to 5.2, which indicates in favor of the formation of five complex forms. Constants of their stability in a wide temperature range are found for each complex form. The values of the thermodynamic functions of the Fe(III) complexation process with FPt are calculated. It is revealed that all the reactions are exothermic. With an increase in the number of coordinated FPt molecules in the inner coordination sphere, the value of ∆G becomes more negative.

Ключевые слова: iron(III); 1-phenyl-2; 3-dimethylpyrazolin-5-thione; complexation-stability constant; thermodynamic functions.

Полный текст статьи

M.M.Mamadvafoev , D.A.Davlatshoev
Geochemical features of intrusive rock complexes and ore sources of Kafandara ore field (Eastern Gissar)
The article discusses the features of Fe, Ti, Mn, S, P, C and H in the intrusive rock complexes of the Kafandara ore field. These data lead to the conclusion that iron for the formation of skarn-magnetite occurrence, and sulfur for the formation of hydrothermal sulfide ones, were borrowed from the composition of Middle Carboniferous granitoids and Early Permian granitoid-porphyry intrusive rocks, respectively, as a result of their mobilization by decaying flows of post-magmatic trans-magmatic solutions, or post-magmatic extra-magmatic solutions.

Ключевые слова: iron; titanium; manganese; sulfur; hydrogen; carbon; phosphorus; rocks; sources of ore matter; intrusive complexes; Kafandara ore field.

Полный текст статьи

Analysis of the characteristics of the alpine climate and its impact on water resources in Tajikistan
The present study is focused on the Upper Vakhsh River Basin where the Fedchenko Glacier is located. The aim of the current study was to use observational climate data to evaluate the response of high altitude areas of the VRB to climate warming through assessment of annual mean air temperature and annual mean precipitation trends and magnitudinal variability. The evaluation of the long-term hydro-climatic variables was carried out employing the original Mann-Kendall test, modified Mann-Kendall (MMK) test and Sens slope estimator. The general pattern in the trend of the annual mean air temperature revealed continuously warming in the catchment over the 1934-1995 time period. The MMK test result showed that the annual mean air temperature trend increased a statistically significant in the high elevation 4165 m at the alpine N.P. Gorbunov (Fedchenko Glacier) climate station during the 1934-1995 time period with a Kendall statistic (Z) equal to 6.266 and a slope value of 0.010, respectively. The results of MMK test exhibited a statistically significant increasing trend of annual mean precipitation in the high elevation stations of the N.P.Gorbunov with a Z value equal to 6.818, and with a slope value equal to 7.824, respectively. The long-term data analysis indicated changes in air temperature and precipitation conditions in the upper part of the VRB.

Ключевые слова: temperature; precipitation; trend; slope value; elevation; Vakhsh River Basin.

Полный текст статьи

M.S.Safarov , A.R.Fazilov
Debris flow activity in Archakapa river basin
The article reflects the results of the review and analysis of Debris flow activity in the Archakapa river basin, as well as the results obtained using remote sensing. The set scientific tasks are solved in the conditions of fieldwork in the study area. The research was carried out using topographic maps, satellite imagery, and aerial photography with the using unmanned aerial vehicles (UAVs). High-quality images of the Debris flow area were obtained (image resolution up to 43 cm), orthophoto map, digital surface model (DSM), digital terrain model (DTM) and 3D model of the Debris flow zone of the river basin Archakapa were prepared. Changes in the lateral boundaries of the river are detected according to data obtained with the UAVs and satellite data. The results obtained on the use of modern technologies and technical means make it possible, under the conditions of climate change, solve problems related to monitoring and forecasting hazardous hydrological phenomena, followed by mapping, analysis, and development of recommendations to prevent possible hazardous hydrological natural phenomena in hard-to-reach areas of Tajikistan, except for the risk to the life of specialists conducting such research.

Ключевые слова: natural disasters; Archakapa; debris flow; unmanned aerial vehicles; aerial photography; satellite imagery; orthomosaic.

Полный текст статьи

G.N.Petrov , A.S.Kodirov , Kh.M.Akhmedov
On legal issues of regulation of relations of countries in the field of joint use of water resources
On the example of the countries of Central Asia, the issues of mutual relations between the countries in the field of joint use of water and energy resources are considered. A list of the main documents of international water law regulating relations between countries in the field of irrigation and hydropower is given. A more precise definition of the term transboundary rivers is proposed. A working principle has been formulated that determines the rights of states to use water and energy resources in their interaction with each other. Two main principles of international law are given and explained - fair and reasonable use and no harm in the use of water and energy resources.

Ключевые слова: water code; runoff; water allocation; hydropower; convention; international water law; national legislation; no harm; river basin; justice; sovereignty; transboundary rivers.