Pub Date : 2024-09-11DOI: 10.1134/s199079312470043x
Yu. Yu. Tsvetkova, V. M. Kislov, E. N. Pilipenko, M. V. Salganskaya, M. V. Tsvetkov
Abstract
The neutralization of sulfur compounds during the filtration combustion of model mixture compositions containing iron sulfide or copper sulfate by adding marble (CaCO3) is studied. It has been experimentally shown that during burning model charge compositions with additions of both iron sulfide and copper sulfate, replacing chemically inert sapphire with marble leads to a decrease in the combustion temperature by approximately 150–200°C. At the same time, the content of CO2 in gaseous products increases, and the concentrations of CO and H2 decrease. The greatest effect on the absorption of sulfur-containing substances when adding marble is shown in experiments where sulfur is present in the fuel in sulfide form: the addition of 50% marble makes it possible to capture 72% of the initial sulfur content, and for compositions with 90% marble in the charge, 85%. The absorption of the sulfur compounds formed during the combustion of model mixture compositions with copper sulfate is much worse. When the charge contains 50 and 85% marble, sulfur-containing compounds were absorbed by only 19 and 24%, respectively.
{"title":"Neutralization of Sulfur-Containing Gases During Coal Filtration Combustion","authors":"Yu. Yu. Tsvetkova, V. M. Kislov, E. N. Pilipenko, M. V. Salganskaya, M. V. Tsvetkov","doi":"10.1134/s199079312470043x","DOIUrl":"https://doi.org/10.1134/s199079312470043x","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>The neutralization of sulfur compounds during the filtration combustion of model mixture compositions containing iron sulfide or copper sulfate by adding marble (CaCO<sub>3</sub>) is studied. It has been experimentally shown that during burning model charge compositions with additions of both iron sulfide and copper sulfate, replacing chemically inert sapphire with marble leads to a decrease in the combustion temperature by approximately 150–200°C. At the same time, the content of CO<sub>2</sub> in gaseous products increases, and the concentrations of CO and H<sub>2</sub> decrease. The greatest effect on the absorption of sulfur-containing substances when adding marble is shown in experiments where sulfur is present in the fuel in sulfide form: the addition of 50% marble makes it possible to capture 72% of the initial sulfur content, and for compositions with 90% marble in the charge, 85%. The absorption of the sulfur compounds formed during the combustion of model mixture compositions with copper sulfate is much worse. When the charge contains 50 and 85% marble, sulfur-containing compounds were absorbed by only 19 and 24%, respectively.</p>","PeriodicalId":768,"journal":{"name":"Russian Journal of Physical Chemistry B","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142214444","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-11DOI: 10.1134/s1990793124700374
V. A. Borisenok
Abstract
To verify the hypothesis of electrical hot spots (HSs)—channels of local electrical breakdowns—the analysis of the electrical properties of condensed explosives and the evaluation of the electric field strength in shock-loaded dielectrics are carried out. It is established that conditions for electrical breakdowns can be created in the compressed zone of explosives due to polarization phenomena (electric field) and shock-induced electrical conductivity (free electrons). The position of the electric model of detonation kinetics are formulated. The results of the experiments with liquid nitromethane (NM) and monocrystalline PENT are explained.
{"title":"About the Electrical Model of Detonation Kinetics of Explosives","authors":"V. A. Borisenok","doi":"10.1134/s1990793124700374","DOIUrl":"https://doi.org/10.1134/s1990793124700374","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>To verify the hypothesis of electrical hot spots (HSs)—channels of local electrical breakdowns—the analysis of the electrical properties of condensed explosives and the evaluation of the electric field strength in shock-loaded dielectrics are carried out. It is established that conditions for electrical breakdowns can be created in the compressed zone of explosives due to polarization phenomena (electric field) and shock-induced electrical conductivity (free electrons). The position of the electric model of detonation kinetics are formulated. The results of the experiments with liquid nitromethane (NM) and monocrystalline PENT are explained.</p>","PeriodicalId":768,"journal":{"name":"Russian Journal of Physical Chemistry B","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142214438","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-11DOI: 10.1134/s1990793124700520
E. A. Salgansky, M. V. Salganskaya, D. O. Glushkov
Abstract
A thermogravimetric analysis of the thermal decomposition of polymethylmethacrylate (PMMA) in a carbon dioxide flow is carried out. The kinetic constants of the process are determined. The heating rate of the sample varies over in wide range and amounts to 2, 5, 8, 20, 35, and 50 K/min. The values of the kinetic constants of PMMA decomposition are determined using the isoconversional method. For the degree of conversion of the substance ranging from 10 to 90%, the values of activation energy for the thermal decomposition of PMMA vary in the range from 213.5 to 194.3 kJ/mol, and the values of the preexponential coefficient change in the range from 1.62 × 1016 to 6.85 × 1012 1/s. The average activation energy for the thermal decomposition of PMMA in a carbon dioxide flow is 206 kJ/mol.
{"title":"Kinetics of Thermal Decomposition of Polymethylmethacrylate in a Carbon Dioxide Environment","authors":"E. A. Salgansky, M. V. Salganskaya, D. O. Glushkov","doi":"10.1134/s1990793124700520","DOIUrl":"https://doi.org/10.1134/s1990793124700520","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>A thermogravimetric analysis of the thermal decomposition of polymethylmethacrylate (PMMA) in a carbon dioxide flow is carried out. The kinetic constants of the process are determined. The heating rate of the sample varies over in wide range and amounts to 2, 5, 8, 20, 35, and 50 K/min. The values of the kinetic constants of PMMA decomposition are determined using the isoconversional method. For the degree of conversion of the substance ranging from 10 to 90%, the values of activation energy for the thermal decomposition of PMMA vary in the range from 213.5 to 194.3 kJ/mol, and the values of the preexponential coefficient change in the range from 1.62 × 10<sup>16</sup> to 6.85 × 10<sup>12</sup> 1/s. The average activation energy for the thermal decomposition of PMMA in a carbon dioxide flow is 206 kJ/mol.</p>","PeriodicalId":768,"journal":{"name":"Russian Journal of Physical Chemistry B","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142214437","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-22DOI: 10.1134/s1990793124700295
Y. A. Kurdyaeva, F. S. Bessarab, O. P. Borchevkina, M. V. Klimenko
Abstract
The influence of atmospheric waves generated by a tropospheric convective source on the state of the upper atmosphere and ionosphere during the recovery phase of the geomagnetic storm on May 27–28, 2017 is studied. A new approach to accounting for atmospheric waves generated by tropospheric convective sources in large-scale atmospheric models without using wave parameterization is proposed and implemented. The developed approach makes it possible to comprehensively study the effects generated by atmospheric waves against the background of various geophysical events, including geomagnetic storms. The multimodel study shows that the proposed approach allows us to reproduce perturbations of the critical frequency of the ionosphere’s ionospheric F2 layer caused by the propagation of atmospheric waves generated by a tropospheric meteorological source. It is shown that the inclusion of a heat inflow source simulating the propagation of atmospheric waves from the lower atmosphere in the global model enhances the effects of a geomagnetic storm, which manifests itself as an additional decrease in the critical frequency of the F2 layer, which can reach 7% of the absolute values.
{"title":"Multimodel Study of the Influence of Atmospheric Waves from a Tropospheric Source on the Ionosphere During a Geomagnetic Storm on May 27–29, 2017","authors":"Y. A. Kurdyaeva, F. S. Bessarab, O. P. Borchevkina, M. V. Klimenko","doi":"10.1134/s1990793124700295","DOIUrl":"https://doi.org/10.1134/s1990793124700295","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>The influence of atmospheric waves generated by a tropospheric convective source on the state of the upper atmosphere and ionosphere during the recovery phase of the geomagnetic storm on May 27–28, 2017 is studied. A new approach to accounting for atmospheric waves generated by tropospheric convective sources in large-scale atmospheric models without using wave parameterization is proposed and implemented. The developed approach makes it possible to comprehensively study the effects generated by atmospheric waves against the background of various geophysical events, including geomagnetic storms. The multimodel study shows that the proposed approach allows us to reproduce perturbations of the critical frequency of the ionosphere’s ionospheric F2 layer caused by the propagation of atmospheric waves generated by a tropospheric meteorological source. It is shown that the inclusion of a heat inflow source simulating the propagation of atmospheric waves from the lower atmosphere in the global model enhances the effects of a geomagnetic storm, which manifests itself as an additional decrease in the critical frequency of the F2 layer, which can reach 7% of the absolute values.</p>","PeriodicalId":768,"journal":{"name":"Russian Journal of Physical Chemistry B","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2024-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141776659","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-22DOI: 10.1134/s1990793124700246
V. V. Zelenov, E. V. Aparina
Abstract
The uptake of O3 on a salt film coating of MgCl2·6H2O at T = 254 and 295 K is studied in the range ([O3] = 2.5 × 1013–1.6 × 1014 cm–3) using a flow reactor with a movable insert and mass spectrometric recording. The time dependence of the uptake coefficient of the ozone at different O3 concentrations is obtained in the relative humidity range from zero to 24%. Using the method of mathematical modeling, based on the shape of the dependence of the uptake coefficient and its time decay on the ozone concentration, the uptake mechanism is established and the elementary kinetic parameters are assessed, based on which it is possible to extrapolate the time behavior of the uptake coefficient to tropospheric conditions at arbitrary ozone concentrations. The ozone uptake at room temperature occurs through the reaction mechanism of an adsorbed molecule on the surface of the substrate. The mechanism includes the stage of reversible adsorption, formation of an adsorbed complex, and its unimolecular decomposition with the release of molecular chlorine into the gas phase. At low temperatures, the uptake proceeds through recombination via the Eley-Rideal reaction mechanism: it includes reversible adsorption, formation of a surface complex, its reaction with an ozone molecule from the gas phase, and the release of an oxygen molecule into the gas phase. In this case, no chlorine is formed. The dependence of the uptake coefficient on relative humidity in the range of values from 0 to 24% at T = 254 K is not detected.
摘要 在 T = 254 和 295 K 的条件下，使用带可移动插入物的流动反应器和质谱记录仪，研究了盐膜 MgCl2-6H2O 在（[O3] = 2.5 × 1013-1.6 × 1014 cm-3）范围内对 O3 的吸收情况。在相对湿度为零到 24% 的范围内，获得了不同 O3 浓度下臭氧吸收系数的时间依赖性。利用数学建模方法，根据吸收系数及其时间衰减对臭氧浓度的依赖性形状，确定了吸收机制，并评估了基本动力学参数，据此可以将吸收系数的时间行为推断到任意臭氧浓度下的对流层条件。室温下的臭氧吸收是通过基质表面吸附分子的反应机制进行的。该机理包括可逆吸附阶段、吸附复合物的形成阶段，以及分子氯释放到气相中的单分子分解阶段。在低温条件下，吸收是通过艾利-里德尔反应机制的重组进行的：该机制包括可逆吸附、形成表面复合物、与气相中的臭氧分子发生反应以及将氧分子释放到气相中。在这种情况下，不会形成氯。在 T = 254 K 的 0 到 24% 的数值范围内，没有检测到吸收系数与相对湿度的关系。
{"title":"Reaction Mechanism of O3 Uptake on MgCl2⋅6H2O as a Sea Salt Component","authors":"V. V. Zelenov, E. V. Aparina","doi":"10.1134/s1990793124700246","DOIUrl":"https://doi.org/10.1134/s1990793124700246","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>The uptake of O<sub>3</sub> on a salt film coating of MgCl<sub>2</sub>·6H<sub>2</sub>O at <i>T</i> = 254 and 295 K is studied in the range ([O<sub>3</sub>] = 2.5 × 10<sup>13</sup>–1.6 × 10<sup>14</sup> cm<sup>–3</sup>) using a flow reactor with a movable insert and mass spectrometric recording. The time dependence of the uptake coefficient of the ozone at different O<sub>3</sub> concentrations is obtained in the relative humidity range from zero to 24%. Using the method of mathematical modeling, based on the shape of the dependence of the uptake coefficient and its time decay on the ozone concentration, the uptake mechanism is established and the elementary kinetic parameters are assessed, based on which it is possible to extrapolate the time behavior of the uptake coefficient to tropospheric conditions at arbitrary ozone concentrations. The ozone uptake at room temperature occurs through the reaction mechanism of an adsorbed molecule on the surface of the substrate. The mechanism includes the stage of reversible adsorption, formation of an adsorbed complex, and its unimolecular decomposition with the release of molecular chlorine into the gas phase. At low temperatures, the uptake proceeds through recombination via the Eley-Rideal reaction mechanism: it includes reversible adsorption, formation of a surface complex, its reaction with an ozone molecule from the gas phase, and the release of an oxygen molecule into the gas phase. In this case, no chlorine is formed. The dependence of the uptake coefficient on relative humidity in the range of values from 0 to 24% at <i>T</i> = 254 K is not detected.</p>","PeriodicalId":768,"journal":{"name":"Russian Journal of Physical Chemistry B","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2024-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141776655","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-22DOI: 10.1134/s1990793124700064
K. Ya. Troshin, N. M. Rubtsov, V. I. Chernysh, G. I. Tsvetkov
Abstract
It is shown that the front of the flame of a thoroughly mixed diluted methane-oxygen mixture at 298 K and 100–300 Torr propagating to the ends of hollow cylindrical and conical obstacles does not form a von Kármán path (vortex shedding) behind them; however, this instability occurs under the same conditions in the flow of hot products after obstacles. The reason that vortex shedding is not observed behind an obstacle during flame propagation but appears in the course of propagation of a reflected stream of hot products is that thermal conductivity reduces the curvature of the flame and leads to its stabilization. Indeed, the convex areas of the chemical reaction zone in a combustible mixture give off more heat in relation to cold ones than in a flat flame: the heat from them is not only transmitted forward in the direction of flame propagation but also in the lateral directions. The resulting cooling of the reaction zone causes the flame regions that burst forward to lag behind. The opposite situation is observed in concave areas, where the temperature rises for the same reasons. The rate of reactions increases and they spread forward faster as the flame spreads. Thus, the surface of the curved front of the flame is evened out. In other words, thermal conductivity has a stabilizing effect on a curved flame. This effect is missing in non-reactive gas. This effect is absent in a nonreacting gas. Calculations based on the acoustic approximation of the Navier–Stokes equations for a compressible reacting medium make it possible to take into account the main observed feature of the flame front approaching an obstacle in the form of a cylinder: vortex shedding is not observed behind the obstacle during flame propagation. Thus, a qualitative model allows obtaining both the mode of the emergence of a von Kármán instability in a chemically inert gas and its absence during flame propagation.
摘要 研究表明，在 298 K 和 100-300 Torr 条件下，充分混合的稀甲烷-氧气混合物的火焰前端在向空心圆柱形和圆锥形障碍物的两端传播时，不会在障碍物后面形成冯-卡尔曼路径（涡流脱落）；然而，在障碍物后的热产物流中，在相同条件下会出现这种不稳定性。在火焰传播过程中，在障碍物后面观察不到涡流脱落，但在热产品反射流的传播过程中却出现了涡流脱落，其原因是导热性降低了火焰的曲率，导致火焰趋于稳定。事实上，在可燃混合物中，化学反应区的凸面区域比平面火焰中的冷面区域释放出更多的热量：凸面区域的热量不仅沿火焰传播方向向前传递，而且还向横向传递。由此产生的反应区冷却导致向前喷发的火焰区域落后。在凹面区域观察到的情况恰恰相反，这里的温度上升也是出于同样的原因。反应速度加快，随着火焰的扩散，反应速度也加快。因此，火焰弯曲前端的表面变得均匀。换句话说，导热性对弯曲火焰具有稳定作用。而在非反应性气体中则没有这种效果。在非反应气体中没有这种效果。根据可压缩反应介质的 Navier-Stokes 方程的声学近似计算，可以考虑到所观察到的火焰前沿接近圆柱形障碍物时的主要特征：在火焰传播过程中，在障碍物后面观察不到涡流脱落。因此，通过定性模型可以获得化学惰性气体中冯-卡尔曼不稳定性的出现模式以及火焰传播过程中不存在这种不稳定性的情况。
{"title":"Features of the Interaction of the Combustion Front of Diluted Methane–Oxygen Mixtures with Hollow Cylindrical and Conical Obstacles at Low Pressures","authors":"K. Ya. Troshin, N. M. Rubtsov, V. I. Chernysh, G. I. Tsvetkov","doi":"10.1134/s1990793124700064","DOIUrl":"https://doi.org/10.1134/s1990793124700064","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>It is shown that the front of the flame of a thoroughly mixed diluted methane-oxygen mixture at 298 K and 100–300 Torr propagating to the ends of hollow cylindrical and conical obstacles does not form a von Kármán path (vortex shedding) behind them; however, this instability occurs under the same conditions in the flow of hot products after obstacles. The reason that vortex shedding is not observed behind an obstacle during flame propagation but appears in the course of propagation of a reflected stream of hot products is that thermal conductivity reduces the curvature of the flame and leads to its stabilization. Indeed, the convex areas of the chemical reaction zone in a combustible mixture give off more heat in relation to cold ones than in a flat flame: the heat from them is not only transmitted forward in the direction of flame propagation but also in the lateral directions. The resulting cooling of the reaction zone causes the flame regions that burst forward to lag behind. The opposite situation is observed in concave areas, where the temperature rises for the same reasons. The rate of reactions increases and they spread forward faster as the flame spreads. Thus, the surface of the curved front of the flame is evened out. In other words, thermal conductivity has a stabilizing effect on a curved flame. This effect is missing in non-reactive gas. This effect is absent in a nonreacting gas. Calculations based on the acoustic approximation of the Navier–Stokes equations for a compressible reacting medium make it possible to take into account the main observed feature of the flame front approaching an obstacle in the form of a cylinder: vortex shedding is not observed behind the obstacle during flame propagation. Thus, a qualitative model allows obtaining both the mode of the emergence of a von Kármán instability in a chemically inert gas and its absence during flame propagation.</p>","PeriodicalId":768,"journal":{"name":"Russian Journal of Physical Chemistry B","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2024-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141776608","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-22DOI: 10.1134/s1990793124700283
S. S. Zamay, V. V. Denisenko, M. V. Klimenko, V. V. Klimenko, S. V. Anisimov
Abstract
It follows from the observational data that variations of the atmospheric electric field occur during geomagnetic storms. In this paper, we present the simulation results of ionospheric electric fields during the main phase of the geomagnetic storm on March 17, 2015, within the framework of a quasi-stationary model of a conductor consisting of the atmosphere and the ionosphere. For this purpose, the satellite data on the global distribution of currents between the magnetosphere and the ionosphere are used to describe the magnetospheric source of the electric field. A variation of the electric potential in the ionosphere leads to a variation of the electric field in the entire atmosphere, including its surface layer. It is important that during a geomagnetic storm, the observatory in which the atmospheric electric field is measured significantly changes its position relative to the direction of the Sun. This leads to significant changes in the ionospheric conductivity above the observatory, which affects both the ionospheric electric field and the atmospheric part of the global electrical circuit (GEC). Therefore, when assessing the effect of a geomagnetic storm on the atmospheric electric field in a particular observatory, it is necessary to take into account the local time when comparing the measurement data with the geomagnetic activity indices. For the storm on March 17–18, 2015, we found that taking into account the variations of the ionospheric electric field when calculating the atmospheric electric field allowed us to reproduce the disturbances of the fair weather electric field observed at the Borok Geophysical Observatory. Based on the simulation results, it is shown that during extremely strong magnetic storms, additional atmospheric electric field variations in some places on the Earth have the same scale as the fair-weather field itself.
{"title":"Mathematical Simulation of the Atmospheric Electric Field Disturbance during a Geomagnetic Storm on 17 March 2015","authors":"S. S. Zamay, V. V. Denisenko, M. V. Klimenko, V. V. Klimenko, S. V. Anisimov","doi":"10.1134/s1990793124700283","DOIUrl":"https://doi.org/10.1134/s1990793124700283","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>It follows from the observational data that variations of the atmospheric electric field occur during geomagnetic storms. In this paper, we present the simulation results of ionospheric electric fields during the main phase of the geomagnetic storm on March 17, 2015, within the framework of a quasi-stationary model of a conductor consisting of the atmosphere and the ionosphere. For this purpose, the satellite data on the global distribution of currents between the magnetosphere and the ionosphere are used to describe the magnetospheric source of the electric field. A variation of the electric potential in the ionosphere leads to a variation of the electric field in the entire atmosphere, including its surface layer. It is important that during a geomagnetic storm, the observatory in which the atmospheric electric field is measured significantly changes its position relative to the direction of the Sun. This leads to significant changes in the ionospheric conductivity above the observatory, which affects both the ionospheric electric field and the atmospheric part of the global electrical circuit (GEC). Therefore, when assessing the effect of a geomagnetic storm on the atmospheric electric field in a particular observatory, it is necessary to take into account the local time when comparing the measurement data with the geomagnetic activity indices. For the storm on March 17–18, 2015, we found that taking into account the variations of the ionospheric electric field when calculating the atmospheric electric field allowed us to reproduce the disturbances of the fair weather electric field observed at the Borok Geophysical Observatory. Based on the simulation results, it is shown that during extremely strong magnetic storms, additional atmospheric electric field variations in some places on the Earth have the same scale as the fair-weather field itself.</p>","PeriodicalId":768,"journal":{"name":"Russian Journal of Physical Chemistry B","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2024-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141776657","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-22DOI: 10.1134/s1990793124700210
P. V. Kozlov, G. Ya. Gerasimov, V. Yu. Levashov, N. G. Bykova, I. E. Zabelinsky, M. A. Kotov
Abstract
A series of probe measurements to determine the electron concentration in the gas ahead of a strong shock wave (SW) front are carried out using a modified double-diaphragm shock tube (DDST-M) of the Institute of Mechanics, Moscow State University. At the same time, the light flux from the region of the shock-heated gas is recorded, which makes it possible to calculate the electron concentration behind the SW using the spectroscopic method. The experiments are carried out in air, oxygen, and nitrogen at SW velocities ranging from 8.3 to 11.3 km/s and an initial pressure of 0.25 Torr in the low-pressure chamber (LPC). The dependencies of the electron concentration on the SW velocity and the distance from the observation point to the SW are obtained. The spectroscopic measurements make it possible to determine the dependence of the electron concentration on the composition of the gaseous medium. The obtained data are compared with the experimental data of other authors.
{"title":"Measurement of the Electron Concentration in the Vicinity of a Strong Shock Wave","authors":"P. V. Kozlov, G. Ya. Gerasimov, V. Yu. Levashov, N. G. Bykova, I. E. Zabelinsky, M. A. Kotov","doi":"10.1134/s1990793124700210","DOIUrl":"https://doi.org/10.1134/s1990793124700210","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>A series of probe measurements to determine the electron concentration in the gas ahead of a strong shock wave (SW) front are carried out using a modified double-diaphragm shock tube (DDST-M) of the Institute of Mechanics, Moscow State University. At the same time, the light flux from the region of the shock-heated gas is recorded, which makes it possible to calculate the electron concentration behind the SW using the spectroscopic method. The experiments are carried out in air, oxygen, and nitrogen at SW velocities ranging from 8.3 to 11.3 km/s and an initial pressure of 0.25 Torr in the low-pressure chamber (LPC). The dependencies of the electron concentration on the SW velocity and the distance from the observation point to the SW are obtained. The spectroscopic measurements make it possible to determine the dependence of the electron concentration on the composition of the gaseous medium. The obtained data are compared with the experimental data of other authors.</p>","PeriodicalId":768,"journal":{"name":"Russian Journal of Physical Chemistry B","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2024-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141776609","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-22DOI: 10.1134/s1990793124700222
N. G. Bykova, A. L. Kusov, P. V. Kozlov, G. Ya. Gerasimov, V. Yu. Levashov, I. E. Zabelinsky
Abstract
An extended version of the previously developed computational procedure SPECTRUM is presented, which allows us to calculate the radiation characteristics of a shock-heated gas, taking into account the decrease in the radiation intensity in an absorbing medium. The procedure is based on a line-by-line calculation of the emission and absorption spectra of the atoms and molecules that make up the studied gas mixture. When calculating the emission spectra of atoms and molecules, the values of spectroscopic constants are taken from well-known databases. The results of calculating the time-integrated spectral characteristics of shock-heated air are compared with the available experimental data obtained in the ultraviolet, visible, and infrared regions of the spectrum.
{"title":"Spectral Model for Calculation of Radiation Characteristics of a Shock-Heated Gas","authors":"N. G. Bykova, A. L. Kusov, P. V. Kozlov, G. Ya. Gerasimov, V. Yu. Levashov, I. E. Zabelinsky","doi":"10.1134/s1990793124700222","DOIUrl":"https://doi.org/10.1134/s1990793124700222","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>An extended version of the previously developed computational procedure SPECTRUM is presented, which allows us to calculate the radiation characteristics of a shock-heated gas, taking into account the decrease in the radiation intensity in an absorbing medium. The procedure is based on a line-by-line calculation of the emission and absorption spectra of the atoms and molecules that make up the studied gas mixture. When calculating the emission spectra of atoms and molecules, the values of spectroscopic constants are taken from well-known databases. The results of calculating the time-integrated spectral characteristics of shock-heated air are compared with the available experimental data obtained in the ultraviolet, visible, and infrared regions of the spectrum.</p>","PeriodicalId":768,"journal":{"name":"Russian Journal of Physical Chemistry B","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2024-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141776610","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-22DOI: 10.1134/s1990793124700180
T. A. Ivanova, E. M. Zubanova, P. S. Timashev, E. N. Golubeva
Abstract
Spin probe electron paramagnetic resonance spectroscopy was applied to estimate release kinetic patterns from globules formed in solutions of thermoresponsive polymers poly-N-isopropylacrylamide (PNIPAM) and graft copolymer based on N-isopropylacrylamide and oligolactide (P(NIPAM-g-PLA)) containing (2,2,6,6-tetramethylpiperidin-1-yl)oxyl (TEMPO) spin probe as a drug model. It is shown that the main mechanism of TEMPO release from globules of thermoresponsive polymers in aqueous solutions above LSCT is Brownian diffusion.
{"title":"EPR Study of Controlled Drug Release from PNIPAM and P(NIPAM-g-PLA) Globules","authors":"T. A. Ivanova, E. M. Zubanova, P. S. Timashev, E. N. Golubeva","doi":"10.1134/s1990793124700180","DOIUrl":"https://doi.org/10.1134/s1990793124700180","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>Spin probe electron paramagnetic resonance spectroscopy was applied to estimate release kinetic patterns from globules formed in solutions of thermoresponsive polymers poly-N-isopropylacrylamide (PNIPAM) and graft copolymer based on N-isopropylacrylamide and oligolactide (P(NIPAM-<i>g</i>-PLA)) containing (2,2,6,6-tetramethylpiperidin-1-yl)oxyl (TEMPO) spin probe as a drug model. It is shown that the main mechanism of TEMPO release from globules of thermoresponsive polymers in aqueous solutions above LSCT is Brownian diffusion.</p>","PeriodicalId":768,"journal":{"name":"Russian Journal of Physical Chemistry B","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2024-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141776616","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
扫码关注我们
求助内容：
应助结果提醒方式：
京公网安备 11010802042870号