Pub Date : 2023-04-03DOI: 10.29235/1561-2430-2023-59-1-81-86
I. Bodnar, A. A. Feshchanka, V. Khoroshko, V. Pavlovsky, I. E. Svitenkov, G. P. Yablonskii
AgIn7S11 single crystals are herein grown by the vertical Bridgman method. The composition of the obtained single crystals is determined by X-ray microprobe analysis as well as the crystal structure – by X-ray diffraction analysis. It is shown that the obtained single crystals are crystallized in the cubic spinel structure. Using transmission spectra in the tem- perature range 10–320 K we determined the band gap of these single crystals and plotted its temperature dependence. This dependence is similar to that of the majority of semiconductor materials, namely, Eg increases with decreasing the tempera- ture. We showed the agreement of the calculated and experimental values.
{"title":"Temperature dependence of the band gap of AgIn7S11 single crystals","authors":"I. Bodnar, A. A. Feshchanka, V. Khoroshko, V. Pavlovsky, I. E. Svitenkov, G. P. Yablonskii","doi":"10.29235/1561-2430-2023-59-1-81-86","DOIUrl":"https://doi.org/10.29235/1561-2430-2023-59-1-81-86","url":null,"abstract":"AgIn7S11 single crystals are herein grown by the vertical Bridgman method. The composition of the obtained single crystals is determined by X-ray microprobe analysis as well as the crystal structure – by X-ray diffraction analysis. It is shown that the obtained single crystals are crystallized in the cubic spinel structure. Using transmission spectra in the tem- perature range 10–320 K we determined the band gap of these single crystals and plotted its temperature dependence. This dependence is similar to that of the majority of semiconductor materials, namely, Eg increases with decreasing the tempera- ture. We showed the agreement of the calculated and experimental values.","PeriodicalId":20584,"journal":{"name":"Proceedings of the National Academy of Sciences of Belarus, Medical series","volume":"81 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88533101","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-04-03DOI: 10.29235/1561-2430-2023-59-1-87-88
A. Editorial
.
．
{"title":"Solovyov Konstantin Nikolaevich (To the 90th Anniversary)","authors":"A. Editorial","doi":"10.29235/1561-2430-2023-59-1-87-88","DOIUrl":"https://doi.org/10.29235/1561-2430-2023-59-1-87-88","url":null,"abstract":"<jats:p>.</jats:p>","PeriodicalId":20584,"journal":{"name":"Proceedings of the National Academy of Sciences of Belarus, Medical series","volume":"46 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86010363","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-04-01DOI: 10.29235/1561-83582023-68-1-40-49
P. Akulich, V. Sednin, M. I. Pozdnyakova
The results of modeling the dehydration of drops of a concentrated liquid, on the example of ceramics, with convective-radiation energy supply under conditions of direct-flow and counter-current phase motion, as well as pulsed counter-flows of gas, are presented. A model for the dehydration of a single drop is formulated based on the equations of heat conduction with a source term and diffusion of moisture, taking into account the change in its size due to evaporation. This takes into account the influence of the convective vapor flow from the evaporating droplet surface (Stefan flow), as well as the blowing of evaporating vapor into the hot gas flow on the heat transfer coefficient (Spalding correction). The impact of infrared radiation is described by the Bouguer equation. The equation of motion of a drop in a gas flow takes into account the forces due to gravity, the difference in velocities and phase densities. As a result of numerical simulation, it was found that with countercurrent phase movement, the intensity of dehydration is higher than with cocurrent flow. This is due to both an increase in the relative velocity of the phases and an increase in the residence time of the drop in the intense region of infrared radiation. It is shown that further intensification of evaporation is possible due to the creation of pulsed counter gas flows. The calculated results are compared with the experimental data, which confirms the adequacy of the model. The results of the study can be useful in the development of new heat technologies and devices for dehydration of concentrated solutions and suspensions.
{"title":"Heat and mass transfer of drops of concentrated solutions during spray dehydration under conditions of convective-radiation energy supply","authors":"P. Akulich, V. Sednin, M. I. Pozdnyakova","doi":"10.29235/1561-83582023-68-1-40-49","DOIUrl":"https://doi.org/10.29235/1561-83582023-68-1-40-49","url":null,"abstract":"The results of modeling the dehydration of drops of a concentrated liquid, on the example of ceramics, with convective-radiation energy supply under conditions of direct-flow and counter-current phase motion, as well as pulsed counter-flows of gas, are presented. A model for the dehydration of a single drop is formulated based on the equations of heat conduction with a source term and diffusion of moisture, taking into account the change in its size due to evaporation. This takes into account the influence of the convective vapor flow from the evaporating droplet surface (Stefan flow), as well as the blowing of evaporating vapor into the hot gas flow on the heat transfer coefficient (Spalding correction). The impact of infrared radiation is described by the Bouguer equation. The equation of motion of a drop in a gas flow takes into account the forces due to gravity, the difference in velocities and phase densities. As a result of numerical simulation, it was found that with countercurrent phase movement, the intensity of dehydration is higher than with cocurrent flow. This is due to both an increase in the relative velocity of the phases and an increase in the residence time of the drop in the intense region of infrared radiation. It is shown that further intensification of evaporation is possible due to the creation of pulsed counter gas flows. The calculated results are compared with the experimental data, which confirms the adequacy of the model. The results of the study can be useful in the development of new heat technologies and devices for dehydration of concentrated solutions and suspensions. ","PeriodicalId":20584,"journal":{"name":"Proceedings of the National Academy of Sciences of Belarus, Medical series","volume":"28 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89553888","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-04-01DOI: 10.29235/1561-8358-2023-68-1-60-71
P. A. Khmarski, A. Solonar, A. Naumov
Features of the indicator channel of the short-range radio navigation systems (for example, the RSBN-4 system) are considered. It was revealed that a significant shortcoming of the indicator channel of the short-range radio navigation is the low accuracy of determining the navigation parameters (azimuth and inclined range of the aircraft) in comparison with on-board equipment. It is shown that one of the possible ways to increase the accuracy of measuring the coordinates of the aircraft in the indicator channel is the use of trajectory processing of radionavigation information whose purpose is to estimate the parameters of the motion of an aircraft in the short-range radio navigation observation zone on the basis of measurements of its instant position for determining the trajectory in the measurement interval and predicting his subsequent movement. The structure of the device for trajectory processing of the indicator channel RSBN can to a great extent repeat the structures of similar devices used in the processing of radar information, taking into account the features of the operation of the indicator channel. The structure of trajectory processing is developed and its features are noted on the example of the system RSBN-4. The performed mathematical modeling confirmed the possibility of a significant increase in the accuracy of the measurement of the coordinates of the aircraft in comparison with the existing indicator channel RSBN-4N.
{"title":"Device of tracking processing for indicator channel of short-range radio navigation systems","authors":"P. A. Khmarski, A. Solonar, A. Naumov","doi":"10.29235/1561-8358-2023-68-1-60-71","DOIUrl":"https://doi.org/10.29235/1561-8358-2023-68-1-60-71","url":null,"abstract":"Features of the indicator channel of the short-range radio navigation systems (for example, the RSBN-4 system) are considered. It was revealed that a significant shortcoming of the indicator channel of the short-range radio navigation is the low accuracy of determining the navigation parameters (azimuth and inclined range of the aircraft) in comparison with on-board equipment. It is shown that one of the possible ways to increase the accuracy of measuring the coordinates of the aircraft in the indicator channel is the use of trajectory processing of radionavigation information whose purpose is to estimate the parameters of the motion of an aircraft in the short-range radio navigation observation zone on the basis of measurements of its instant position for determining the trajectory in the measurement interval and predicting his subsequent movement. The structure of the device for trajectory processing of the indicator channel RSBN can to a great extent repeat the structures of similar devices used in the processing of radar information, taking into account the features of the operation of the indicator channel. The structure of trajectory processing is developed and its features are noted on the example of the system RSBN-4. The performed mathematical modeling confirmed the possibility of a significant increase in the accuracy of the measurement of the coordinates of the aircraft in comparison with the existing indicator channel RSBN-4N.","PeriodicalId":20584,"journal":{"name":"Proceedings of the National Academy of Sciences of Belarus, Medical series","volume":"12 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75267116","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-04-01DOI: 10.29235/1561-8358-2023-68-1-24-31
S. Yankevich, I. N. Khrol, N. A. Kalinovskij
The properties of materials for airless wheel propulsion of vehicles, including electric ones, have been studied. The experimental substantiation of the choice of the type of polymer matrices and compositions of reinforcing fillers for the manufacture of an airless wheel mover of electric vehicles has been carried out. To test the basic epoxy matrix, part of the samples without the addition of reinforcing fibers was cured at room temperature (L-285H), and the rest (L-285G) – when heated to 60 °C. In order to improve the strength characteristics of the epoxy matrix L-285G, glass reinforcement was carried out with EC16 1600T-16(400) glass reinforcement. The Smooth-Cast 300 Series was chosen as the matrix for performing samples based on injection-molded polyurethanes. Samples are made of base polyurethane under various conditions: at atmospheric rejection (SC), under vacuum 0.8 kPa (SC-0.8) and during vibration-induced curing (SCV). Comparative tests were carried out, which showed differences in the mechanical properties of the base matrices based on epoxy resins and injection-molded polyurethanes, in particular, the relative elongation of samples from injection-molded polyurethane by more than 2 times. It is established that the most rational use of injection-molded polyurethane is application as damping elements, and the material for manufacturing spokes dampers is composite SCV-S-20. It is advisable to manufacture products from the resulting composite when vibrations are applied to the mold and with preliminary vacuuming at a vacuum of 0.8 kPa of the components of the polyurethane matrix, which reduces the number of internal defects in the form of shells. Since vacuuming of the product during polymerization does not give a significant effect due to the presence of a set of specialized deaeration additives in the base matrix, it is proposed to carry it out under constant control, since exceeding the vacuum in the range from 0.8 to 0.9 kPa entails decomposition of individual matrix components with foam formation.
{"title":"Evaluation of the strength characteristics of polymer materials for the manufacture of personal electric vehicle elements","authors":"S. Yankevich, I. N. Khrol, N. A. Kalinovskij","doi":"10.29235/1561-8358-2023-68-1-24-31","DOIUrl":"https://doi.org/10.29235/1561-8358-2023-68-1-24-31","url":null,"abstract":"The properties of materials for airless wheel propulsion of vehicles, including electric ones, have been studied. The experimental substantiation of the choice of the type of polymer matrices and compositions of reinforcing fillers for the manufacture of an airless wheel mover of electric vehicles has been carried out. To test the basic epoxy matrix, part of the samples without the addition of reinforcing fibers was cured at room temperature (L-285H), and the rest (L-285G) – when heated to 60 °C. In order to improve the strength characteristics of the epoxy matrix L-285G, glass reinforcement was carried out with EC16 1600T-16(400) glass reinforcement. The Smooth-Cast 300 Series was chosen as the matrix for performing samples based on injection-molded polyurethanes. Samples are made of base polyurethane under various conditions: at atmospheric rejection (SC), under vacuum 0.8 kPa (SC-0.8) and during vibration-induced curing (SCV). Comparative tests were carried out, which showed differences in the mechanical properties of the base matrices based on epoxy resins and injection-molded polyurethanes, in particular, the relative elongation of samples from injection-molded polyurethane by more than 2 times. It is established that the most rational use of injection-molded polyurethane is application as damping elements, and the material for manufacturing spokes dampers is composite SCV-S-20. It is advisable to manufacture products from the resulting composite when vibrations are applied to the mold and with preliminary vacuuming at a vacuum of 0.8 kPa of the components of the polyurethane matrix, which reduces the number of internal defects in the form of shells. Since vacuuming of the product during polymerization does not give a significant effect due to the presence of a set of specialized deaeration additives in the base matrix, it is proposed to carry it out under constant control, since exceeding the vacuum in the range from 0.8 to 0.9 kPa entails decomposition of individual matrix components with foam formation.","PeriodicalId":20584,"journal":{"name":"Proceedings of the National Academy of Sciences of Belarus, Medical series","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74312322","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-04-01DOI: 10.29235/1561-8358-2023-68-1-82-88
I. Zhuk, K. Husak, D. Hakimov
The results of a study on the choice of the optimal measurement geometry, measuring capacity and method of sealing the measuring capacity for determining the concentration of radon-222 in samples of mineral radon water are presented. Studies of radon water samples were carried out in laboratory conditions on a stationary gamma spectrometer based on a semiconductor Ge(Li) detector. The concentration measurements in the samples were carried out in accordance with MVI. MN 3421-2010 “Methodology for measuring the volumetric and concentration of gamma-emitting radionuclides on gamma spectrometers with semiconductor detectors” for standard plastic vessels “Denta, 0.1 l” and “Marinelli, 1 l”, and glass containers with a volume of 0.5 l with lids for twisting and seaming. The results of the research showed that the leakage of radon from a glass container with a metal lid for sealing is minimal. This method of sampling and sealing the measuring vessel makes it possible to increase the accuracy of the presented measurement results by reducing the corrections for sample preparation when calculating the expanded measurement uncertainty. A glass container with a volume of 0.5 l with a metal cap for seaming was used to measure the concentration of radon in samples of mineral radon water taken from wells and a drinking fountain of the Radon sanatorium of Belagrozdravnitsa JSC (Dyatlovo District, Grodno Region). The concentration range was 760–2100 Bq/kg. The selected measuring container, the method of its sealing and the measurement geometry can be used for future measurements of the radon concentration in samples of mineral radon water taken in the sanatoriums of the Republic of Belarus.
{"title":"Using the gamma spectrometry method to determine the concentration of radon in samples of mineral radon water","authors":"I. Zhuk, K. Husak, D. Hakimov","doi":"10.29235/1561-8358-2023-68-1-82-88","DOIUrl":"https://doi.org/10.29235/1561-8358-2023-68-1-82-88","url":null,"abstract":"The results of a study on the choice of the optimal measurement geometry, measuring capacity and method of sealing the measuring capacity for determining the concentration of radon-222 in samples of mineral radon water are presented. Studies of radon water samples were carried out in laboratory conditions on a stationary gamma spectrometer based on a semiconductor Ge(Li) detector. The concentration measurements in the samples were carried out in accordance with MVI. MN 3421-2010 “Methodology for measuring the volumetric and concentration of gamma-emitting radionuclides on gamma spectrometers with semiconductor detectors” for standard plastic vessels “Denta, 0.1 l” and “Marinelli, 1 l”, and glass containers with a volume of 0.5 l with lids for twisting and seaming. The results of the research showed that the leakage of radon from a glass container with a metal lid for sealing is minimal. This method of sampling and sealing the measuring vessel makes it possible to increase the accuracy of the presented measurement results by reducing the corrections for sample preparation when calculating the expanded measurement uncertainty. A glass container with a volume of 0.5 l with a metal cap for seaming was used to measure the concentration of radon in samples of mineral radon water taken from wells and a drinking fountain of the Radon sanatorium of Belagrozdravnitsa JSC (Dyatlovo District, Grodno Region). The concentration range was 760–2100 Bq/kg. The selected measuring container, the method of its sealing and the measurement geometry can be used for future measurements of the radon concentration in samples of mineral radon water taken in the sanatoriums of the Republic of Belarus.","PeriodicalId":20584,"journal":{"name":"Proceedings of the National Academy of Sciences of Belarus, Medical series","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85479767","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-04-01DOI: 10.29235/1561-8358-2023-68-1-32-39
M. Zhuravkov, A. B. Petrovskiy, V. Y. Prushak, M. A. Nikolaitchik, D. Puzanov, N. M. Klimkovich
The geomechanical model is proposed and the technology of numerical simulation is developed. Carried out computer simulation of the geomechanical state of the being undermined repeatedly rock massifs of the 3rd potash level of the Starobin deposit taking into account its structural and strength features, as well as the technological schemes of the primary mining. The regularities of the stress-strain zones formation in the undermined rock mass containing mined out mine workings and inter-panel pillars were determined. It is shown that the stability of the workings located in the undermined areas significantly depends on the time passed since the primary mining and on the location of the workings in the massif relative to the location of the primary mining operations. It is determined that the most dangerous for repeated mining are the areas of generalized shear, since the processes of rock mass movement and failure are most likely to be active in these areas. In the areas of generalized compression, the processes of compaction of caved rock take place. As a consequence, after a considerable period of time, the state of the rock massif in these areas can be treated as approximating to the natural state, without additional structural failures. In such areas, the effective mechanical characteristics of the rock massifs are practically restored. Therefore, the greatest stability of mine workings will be achieved when they are placed in the area of generalized compression stress state in the zone of caved, compacted rocks of the mined out roadways and faces.
{"title":"Modeling of the geomechanical state of the rock massifs being undermined repeatedly","authors":"M. Zhuravkov, A. B. Petrovskiy, V. Y. Prushak, M. A. Nikolaitchik, D. Puzanov, N. M. Klimkovich","doi":"10.29235/1561-8358-2023-68-1-32-39","DOIUrl":"https://doi.org/10.29235/1561-8358-2023-68-1-32-39","url":null,"abstract":"The geomechanical model is proposed and the technology of numerical simulation is developed. Carried out computer simulation of the geomechanical state of the being undermined repeatedly rock massifs of the 3rd potash level of the Starobin deposit taking into account its structural and strength features, as well as the technological schemes of the primary mining. The regularities of the stress-strain zones formation in the undermined rock mass containing mined out mine workings and inter-panel pillars were determined. It is shown that the stability of the workings located in the undermined areas significantly depends on the time passed since the primary mining and on the location of the workings in the massif relative to the location of the primary mining operations. It is determined that the most dangerous for repeated mining are the areas of generalized shear, since the processes of rock mass movement and failure are most likely to be active in these areas. In the areas of generalized compression, the processes of compaction of caved rock take place. As a consequence, after a considerable period of time, the state of the rock massif in these areas can be treated as approximating to the natural state, without additional structural failures. In such areas, the effective mechanical characteristics of the rock massifs are practically restored. Therefore, the greatest stability of mine workings will be achieved when they are placed in the area of generalized compression stress state in the zone of caved, compacted rocks of the mined out roadways and faces. ","PeriodicalId":20584,"journal":{"name":"Proceedings of the National Academy of Sciences of Belarus, Medical series","volume":"167 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79606841","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-04-01DOI: 10.29235/1561-8358-2023-68-1-7-17
I. Gasenkova, N. Mukhurov, I. Andrukhovich
In the paper, the possibility to produce anodic aluminum oxide (AAO) featuring one-dimensional photonic crystal along the normal to the surface is shown. The AAO structure is represented by alternating layers of different porosity and is formed in a viscous electrolyte based on sulfuric acid and ethylene glycol at the periodically varying from high (1.8 mA/cm2) to low (0.4 mA/cm2) current density with a rectangular pulse shape. The pore sizes and interpore distance, pore density and porosity, thickness and period of the AAO structure have been determined. The specular reflection spectra features for single layers that make up the AAO structure and for one-dimensional photonic crystals structures consisting of 165 periods have been studied. An increase in the porosity of the upper layers of the structure due to chemical etching of the pores during the oxide growth is noted. It is shown that the invariance of the spectral position of the photonic band gap for AAO structures is achieved by a 0.1 % decrease in charge at each subsequent anodizing cycle during their formation, which leads to a decrease in the period of the structure in the lower layers, compensating for the increase in the upper layers porosity. The reflection spectra have been analyzed for the incidence angles of 10° and 30° and used to calculate the period of the structure and the effective refractive index. The effective refractive index of the single layers that make up the AAO structure is calculated using the optical Fabry–Perot oscillations. For AAO with the properties of one-dimensional photonic crystal, a green color is observed at normal light incidence, and an iridescent color is observed when the angle changes. AAO can be used as a decorative coating on the housings of electronic devices (tablets, laptops, phones, etc.) and when creating design objects made of aluminum and its alloys.
{"title":"Anodizing aluminum in a viscous electrolyte to produce one-dimensional photonic crystals","authors":"I. Gasenkova, N. Mukhurov, I. Andrukhovich","doi":"10.29235/1561-8358-2023-68-1-7-17","DOIUrl":"https://doi.org/10.29235/1561-8358-2023-68-1-7-17","url":null,"abstract":"In the paper, the possibility to produce anodic aluminum oxide (AAO) featuring one-dimensional photonic crystal along the normal to the surface is shown. The AAO structure is represented by alternating layers of different porosity and is formed in a viscous electrolyte based on sulfuric acid and ethylene glycol at the periodically varying from high (1.8 mA/cm2) to low (0.4 mA/cm2) current density with a rectangular pulse shape. The pore sizes and interpore distance, pore density and porosity, thickness and period of the AAO structure have been determined. The specular reflection spectra features for single layers that make up the AAO structure and for one-dimensional photonic crystals structures consisting of 165 periods have been studied. An increase in the porosity of the upper layers of the structure due to chemical etching of the pores during the oxide growth is noted. It is shown that the invariance of the spectral position of the photonic band gap for AAO structures is achieved by a 0.1 % decrease in charge at each subsequent anodizing cycle during their formation, which leads to a decrease in the period of the structure in the lower layers, compensating for the increase in the upper layers porosity. The reflection spectra have been analyzed for the incidence angles of 10° and 30° and used to calculate the period of the structure and the effective refractive index. The effective refractive index of the single layers that make up the AAO structure is calculated using the optical Fabry–Perot oscillations. For AAO with the properties of one-dimensional photonic crystal, a green color is observed at normal light incidence, and an iridescent color is observed when the angle changes. AAO can be used as a decorative coating on the housings of electronic devices (tablets, laptops, phones, etc.) and when creating design objects made of aluminum and its alloys.","PeriodicalId":20584,"journal":{"name":"Proceedings of the National Academy of Sciences of Belarus, Medical series","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84283308","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-04-01DOI: 10.29235/1561-8358-2023-68-1-50-59
A. I. Olshanski, A. L. Klimentyev, A. A. Kotow
The results of the study of drying thin natural leather pasted on a smooth surface are presented. The results of solving the differential equation of non-stationary heat conduction with constant thermophysical coefficients are used to determine the average temperature during the period of decreasing drying rate. The calculated values of temperatures for moisture-proof and moisture-free skin surfaces are given. Methods for simplifying solutions of nonlinear equations with the aim of linearizing these equations for approximating solutions with variable transport coefficients are considered. The use of the method of piecewise stepwise approximation of the transfer coefficients with constant values of these coefficients over short time intervals showed that for low-intensity drying processes, the solutions of the linear heat equation are implemented quite accurately, confirming the regularities obtained empirically. The calculation of the duration of drying according to the method of B. S. Sazhin is given. The results of the processing of experimental curves for drying leathers pasted are presented. The reliability of the obtained equations is verified and the experiment is compared with the calculated values using the formulas. The obtained approximate analytical solutions with reliable values of the transfer coefficients, confirmed by experimentally established regularities, are of practical importance. Together with experimental methods, analytical methods make it possible to establish optimal drying regimes and more accurately generalize experimental data.
{"title":"Heat and mass transfer in the processes of drying thin natural leathers pasted on smooth surfaces","authors":"A. I. Olshanski, A. L. Klimentyev, A. A. Kotow","doi":"10.29235/1561-8358-2023-68-1-50-59","DOIUrl":"https://doi.org/10.29235/1561-8358-2023-68-1-50-59","url":null,"abstract":"The results of the study of drying thin natural leather pasted on a smooth surface are presented. The results of solving the differential equation of non-stationary heat conduction with constant thermophysical coefficients are used to determine the average temperature during the period of decreasing drying rate. The calculated values of temperatures for moisture-proof and moisture-free skin surfaces are given. Methods for simplifying solutions of nonlinear equations with the aim of linearizing these equations for approximating solutions with variable transport coefficients are considered. The use of the method of piecewise stepwise approximation of the transfer coefficients with constant values of these coefficients over short time intervals showed that for low-intensity drying processes, the solutions of the linear heat equation are implemented quite accurately, confirming the regularities obtained empirically. The calculation of the duration of drying according to the method of B. S. Sazhin is given. The results of the processing of experimental curves for drying leathers pasted are presented. The reliability of the obtained equations is verified and the experiment is compared with the calculated values using the formulas. The obtained approximate analytical solutions with reliable values of the transfer coefficients, confirmed by experimentally established regularities, are of practical importance. Together with experimental methods, analytical methods make it possible to establish optimal drying regimes and more accurately generalize experimental data. ","PeriodicalId":20584,"journal":{"name":"Proceedings of the National Academy of Sciences of Belarus, Medical series","volume":"34 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82812446","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-04-01DOI: 10.29235/1561-2430-2023-59-1-7-17
N. N. Vorob’ev
Throughout this paper, all groups are finite. A group class closed under taking homomorphic images and finite subdirect products is called a formation. The symbol σ denotes some partition of the set of all primes. V. G. Safonov, I. N. Safonova, A. N. Skiba (Commun. Algebra. 2020. Vol. 48, № 9. P. 4002–4012) defined a generalized formation σ-function. Any function f of the form f : σ È {Ø} → {formations of groups}, where f(Ø) ≠ ∅, is called a generalized formation σ-function. Generally local formations or so-called Baer-σ-local formations are defined by means of generalized formation σ-functions. The set of all such formations partially ordered by set inclusion is a lattice. In this paper it is proved that the lattice of all Baerσ-local formations is algebraic and modular.
在本文中，所有群都是有限的。在取同态象和有限次直积的条件下闭合的群类称为群。符号σ表示所有素数集合的某种划分。V. G. Safonov, I. N. Safonova, A. N. Skiba (common)。代数》2020。第四十八卷第九期P. 4002-4012)定义了广义构造σ-函数。凡形式为f: σ È {Ø}→{群的构造}的函数f，其中f(Ø)≠∅，称为广义构造σ-函数。一般局部地层或所谓的Baer-σ-局部地层是用广义地层σ-函数来定义的。所有这些由集合包含部分排序的构成的集合是一个格。本文证明了所有baer σ-局部形的格是代数的和模的。
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