Russian Journal of Physical Chemistry B最新文献

{"title":"The Role of Third-Body Collision Efficiency in Autoignition of Hydrogen–Air Mixtures","authors":"A. M. Tereza,&nbsp;G. L. Agafonov,&nbsp;E. K. Anderzhanov,&nbsp;A. S. Betev,&nbsp;S. P. Medvedev,&nbsp;V. N. Mikhalkin,&nbsp;S. V. Khomik,&nbsp;T. T. Cherepanova","doi":"10.1134/S1990793124700416","DOIUrl":"10.1134/S1990793124700416","url":null,"abstract":"<p>Numerical simulations of autoignition of lean (6% H₂), stoichiometric, and rich (90% H₂) hydrogen–air mixtures have been performed to examine the influence of third-body efficiency (chaperon efficiency, CE) on the value of ignition delay, τ. The temperature ranges explored in the computations are 850–1000 K for <i>P</i>₀ = 1 bar and 1000–1200 K for <i>P</i>₀ = 6 bar. By using a detailed kinetic mechanism, it has been found that the sensitivity of ignition delay to CE is the highest for the reaction step H + O₂ + M = HO₂ + M, which can lead to a variation in τ by a factor of 2 to 3. A pressure increase or deviation from stoichiometry reduces the sensitivity. The influence of CE is qualitatively different and weaker for the reaction step OH + OH + M = H₂O₂ + M.</p>","PeriodicalId":768,"journal":{"name":"Russian Journal of Physical Chemistry B","volume":"18 4","pages":"965 - 972"},"PeriodicalIF":1.4,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142214441","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}

{"title":"Calculation of Radiation Characteristics of Shock-Heated Air by the Direct Simulation Monte Carlo Method","authors":"A. L. Kusov,&nbsp;N. G. Bykova,&nbsp;G. Ya. Gerasimov,&nbsp;P. V. Kozlov,&nbsp;I. E. Zabelinsky,&nbsp;V. Yu. Levashov","doi":"10.1134/S1990793124700398","DOIUrl":"10.1134/S1990793124700398","url":null,"abstract":"<p>The results of modeling the radiation characteristics of the air behind the front of a strong shock wave, performed using the direct simulation Monte Carlo method, are presented. The model used takes into account various physical and chemical processes occurring in shock-heated air, including the translational-rotational and translational-vibrational energy exchange, kinetics of chemical reactions, and excitation of electronic levels of atoms and molecules, as well as the emission and absorption processes for a discrete spectrum. As a result of the calculations, time-integrated spectrograms of the volumetric radiation power of shock-heated air are obtained in absolute units in the range of shock wave velocities from 7.4 to 10.7 km/s at a gas pressure in front of the shock wave front of 0.25 Torr. The calculation data are compared with the experimental data obtained on a DDST-M double-diaphragm shock tube of the Institute of Mechanics of Moscow State University.</p>","PeriodicalId":768,"journal":{"name":"Russian Journal of Physical Chemistry B","volume":"18 4","pages":"945 - 951"},"PeriodicalIF":1.4,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142214442","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}

{"title":"Combustion Regimes of Hydrogen at Its Direct Injection Into the Internal Combustion Engine Chamber","authors":"A. E. Smygalina,&nbsp;A. D. Kiverin","doi":"10.1134/S199079312470060X","DOIUrl":"10.1134/S199079312470060X","url":null,"abstract":"<p>This paper analyzes processes in the combustion chamber of spark ignition engine under direct jet injection of hydrogen during the compression stroke. Numerical modeling is used to study the features of mixing hydrogen with air and its combustion after ignition from a spark at the instant when the piston reaches the top dead center (TDC). The combustion regimes that develop when the injection pressure is varied from 20 to 140 atm, and the start of injection, from 180° to 45° of the crank angle (CA) before the TDC, are considered. In all cases the mass of hydrogen necessary for the formation of a stoichiometric mixture with air during injection into the combustion chamber is supplied. It is found that the most uniform mixture at the time of ignition is formed with advanced injection (180°–135° of the CA before the TDC) at a relatively low pressure (20–60 atm). The ignition of a uniform mixture in the conditions considered leads to detonation regime of combustion. A lower degree of uniformity of the mixture corresponds to a slow, deflagration combustion regime. It is important to note that nonuniformity of the mixture determines the ambiguity of the formation of a certain combustion regime, depending on the local mixture composition in the vicinity of a spark. At the same time, the slowest combustion regime provides the maximum hydrogen combustion incompleteness, up to 8.2%. Generally, the considered ranges of injection pressure and start of injection lead to satisfactory levels of incompleteness of hydrogen combustion of less than 4%.</p>","PeriodicalId":768,"journal":{"name":"Russian Journal of Physical Chemistry B","volume":"18 4","pages":"1048 - 1059"},"PeriodicalIF":1.4,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142214451","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}

{"title":"The Structure of DNA in Anabiotic and Mummified Escherichia coli Cells","authors":"Yu. F. Krupyanskii,&nbsp;V. V. Kovalenko,&nbsp;N. G. Loiko,&nbsp;E. V. Tereshkin,&nbsp;K. B. Tereshkina,&nbsp;A. N. Popov","doi":"10.1134/S1990793124700441","DOIUrl":"10.1134/S1990793124700441","url":null,"abstract":"<p>The structural organization of DNA in stressed (with increased stress resistance), anabiotic, and mummified cells obtained by introducing 4-hexylresorcinol in different concentrations at different stages of cell culture growth is studied using the synchrotron radiation diffraction technique. The experimental studies allow us to conclude that 4-hexylresorcinol is the initiator of the transition of cells into an anabiotic and mummified state in the stationary stage of growth. In the prestationary stage, in the studied concentration range, 4-hexylresorcinol initiates the transition of cells into a mummified state but not into an anabiotic state, which indicates that DNA is unprepared for the crystallization process in these bacteria. The structure of DNA inside a cell in an anabiotic dormant state (the almost complete absence of metabolism) and dormant state (starvation stress) coincide (form nanocrystalline structures). The data indicate the universality of DNA condensation or the universality of DNA protection by the Dps protein in the dormant state, regardless of the type of stress. The mummified state (the complete absence of metabolism, irreversible to life) is very different in structure (has no order within the cell).</p>","PeriodicalId":768,"journal":{"name":"Russian Journal of Physical Chemistry B","volume":"18 4","pages":"1134 - 1140"},"PeriodicalIF":1.4,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142214475","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}

{"title":"Porous Polymer Compositions Based on Mixed Colloidal Suspensions Under Ultrasonic Dispersion and Microwave Heating","authors":"V. N. Gorshenev,&nbsp;I. A. Maklakova,&nbsp;M. A. Yakovleva","doi":"10.1134/S1990793124700453","DOIUrl":"10.1134/S1990793124700453","url":null,"abstract":"<p>A new method for mixing solutions and suspensions containing thermodynamically immiscible dispersion media based on the use of ultrasonic dispersion and thermally stimulated microwave heating has been proposed. The results of a study of a number of functional composites obtained by mixing solutions of biodegradable polymers in chloroform with aqueous suspensions of natural polymers are presented. The possibility of obtaining polymer composites doped with magnetic nanoparticles and drugs by this method is considered. It has been established that the proposed method of mixing makes it possible to combine suspensions of polymers of different kinds in the composition of composites suitable for creating porous, hygroscopic, and magnetically controlled materials for biomedical and environmental applications.</p>","PeriodicalId":768,"journal":{"name":"Russian Journal of Physical Chemistry B","volume":"18 4","pages":"1141 - 1147"},"PeriodicalIF":1.4,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142214476","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}

{"title":"Experimental Study of the Ignition of a Stoichiometric Propylene–Oxygen–Argon Mixture Behind a Reflected Shock Wave","authors":"P. V. Kozlov,&nbsp;M. A. Kotov,&nbsp;G. Ya. Gerasimov,&nbsp;V. Yu. Levashov,&nbsp;N. G. Bykova,&nbsp;I. E. Zabelinskii","doi":"10.1134/S1990793124700568","DOIUrl":"10.1134/S1990793124700568","url":null,"abstract":"<p>The self-ignition of a propylene–oxygen–argon stoichiometric mixture with a volumetric argon content of 95% is studied. The experiments are performed on a shock tube, which is part of the Shock Tube Experimental Complex of the Institute of Mechanics of Moscow State University, in conditions behind the reflected shock wave. The time dependencies of signals from a piezoelectric pressure sensor, a thermoelectric detector, and an optical section configured to record the radiation of electronically excited radicals OH^• (λ = 302 nm), CH^• (λ = 427 nm, and molecular carbon <span>({text{C}}_{2}^{centerdot })</span> (λ = 553 nm) are analyzed. The ignition delay times τ_<i>ign</i> are measured in the temperature range <i>T</i> = 1200–2460 K and pressures <i>p</i> = 4.5–25 atm. The data obtained are compared with the results of other authors.</p>","PeriodicalId":768,"journal":{"name":"Russian Journal of Physical Chemistry B","volume":"18 4","pages":"1019 - 1024"},"PeriodicalIF":1.4,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142214447","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}

{"title":"Thermodynamic Evaluation of Hydrogen Production Modes During the Pyrolysis of Ammonia in a Filtration Combustion Moving Bed Reactor","authors":"E. A. Salgansky,&nbsp;M. V. Salganskaya,&nbsp;I. V. Sedov","doi":"10.1134/S1990793124700593","DOIUrl":"10.1134/S1990793124700593","url":null,"abstract":"<p>A new process is proposed for the pyrolysis of ammonia in a filtration combustion moving bed reactor to produce hydrogen. The process can be implemented in reactors with energy recovery with a separate supply of reagents (including swiss-roll reactors, etc.). The mass-energy balance of the process is calculated. The pyrolysis products are analyzed under a condition of thermodynamic equilibrium with varying temperature and pressure. The system pressure is varied from 1 to 10 bar. The temperature range from 300 to 1100 K iss considered. It is shown that the pyrolysis of ammonia ends at a temperature of 620 K at atmospheric pressure. An increase in pressure in the system leads to a slight increase in the temperature of the pyrolysis of ammonia. The portion of hydrogen that needs to be burned to cover the energy for heating and pyrolysis of the initial ammonia in the case of an adiabatic reactor is 0.13. From one mole of ammonia it is possible to obtain 1.31 moles of hydrogen.</p>","PeriodicalId":768,"journal":{"name":"Russian Journal of Physical Chemistry B","volume":"18 4","pages":"1042 - 1047"},"PeriodicalIF":1.4,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142214452","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}

{"title":"Effect of Implanted Titanium, Vanadium or Chromium on Boron Nitride Surface for Increasing Carbon Monoxide Adsorption: Designing Gas Sensor for Green Chemistry Future","authors":"F. Mollaamin,&nbsp;M. Monajjemi","doi":"10.1134/S1990793124700519","DOIUrl":"10.1134/S1990793124700519","url":null,"abstract":"<p>Adsorption of toxic gas of carbon monoxide (CO) molecules by using transition metals (TM) of titanium (Ti), vanadium (V) or chromium (Cr)-doped boron nitride (B₅N₁₀) nanocage have been investigated using density functional theory. The partial density of states can evaluate a determined charge assembly between gas molecules and TM–B₄N₁₀ which indicates the competition among dominant complexes of Ti, V, Cr. Based on nuclear quadrupole resonance analysis, TM-doped on B₅N₁₀ has shown the lowest fluctuation in electric potential and the highest negative atomic charge including 0.5883 (chromium), 0.6893 (vanadium) and 0.7499 coulomb (titanium), respectively, have presented the most tendency for being the electron acceptors. Furthermore, the reported results of nuclear magnetic resonance spectroscopy have exhibited that the yield of electron accepting for doping atoms on the TM–B₄N₁₀ through gas molecules adsorption can be ordered as: Cr &gt; V &gt; Ti that exhibits the strength of covalent bond between titanium, vanadium, chromium, and CO towards toxic gas removal from air. In fact, the adsorption of CO gas molecules can introduce spin polarization on the TM–B₄N₁₀ which specifies that these surfaces may be employed as magnetic scavenging surface as a gas detector. Regarding IR spectroscopy, doped nanocages of Ti–B₄N₁₀, V–B₄N₁₀, and Cr–B₄N₁₀, respectively, have the most fluctuations and the highest adsorption tendency for gas molecules which can address specific questions on the individual effect of charge carriers (gas molecule-nanocage), as well as doping atoms on the overall structure. Based on the results of <span>(Delta G_{{{text{ads}}}}^{{text{o}}})</span> amounts in this research, the maximum efficiency of Ti, V, Cr atoms doping of B₅N₁₀ for gas molecules adsorption depends on the covalent bond between CO molecules and TM–B₄N₁₀ as a potent sensor for air pollution removal. Therefore, for a given number of carbon donor sites in CO, the stabilities of complexes owing to doping atoms of Ti, V, Cr can be considered as: CO@Cr–B₄N₁₀ &gt; CO@V–B₄N₁₀&gt; CO@Ti–B₄N₁₀.</p>","PeriodicalId":768,"journal":{"name":"Russian Journal of Physical Chemistry B","volume":"18 4","pages":"1199 - 1216"},"PeriodicalIF":1.4,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142214489","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}

{"title":"Kinetics of Thermal Decomposition of Polymethylmethacrylate in an Oxidizing Environment","authors":"E. A. Salgansky,&nbsp;M. V. Salganskaya,&nbsp;D. O. Glushkov","doi":"10.1134/S1990793124700362","DOIUrl":"10.1134/S1990793124700362","url":null,"abstract":"<p>Using thermogravimetric analysis (TGA), the kinetic constants of the thermal decomposition of polymethylmethacrylate (PMMA) in an oxidizing environment are determined over a wide range of sample heating rates. The values of the kinetic constants of polymer decomposition are determined by the Kissinger method. It is shown that as the degree of polymer decomposition increases, the rate constant decreases at a constant temperature.</p>","PeriodicalId":768,"journal":{"name":"Russian Journal of Physical Chemistry B","volume":"18 4","pages":"913 - 917"},"PeriodicalIF":1.4,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142214435","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}

{"title":"Conductive and Convective Combustion Modes of Granular Mixtures of Ti–C–NiCr","authors":"B. S. Seplyarskii,&nbsp;R. A. Kochetkov,&nbsp;T. G. Lisina,&nbsp;N. I. Abzalov","doi":"10.1134/S1990793124700404","DOIUrl":"10.1134/S1990793124700404","url":null,"abstract":"<p>The combustion modes of powder and granular mixtures (100 – <i>X</i>)(Ti + C) + <i>X</i>NiCr (<i>X</i> = 0–30%) containing Ti powders of different dispersion with different amounts of impurity gases in them are studied. The experimental setup provided the filtration of impurity gases released during combustion in the cocurrent direction or through the side surface of the sample. The difference between the experimental burning velocities of powder mixtures with titanium of a different fineness is explained using a convective-conductive combustion model. For granular mixtures based on Ti powder with a characteristic size of 120 μm, it is shown that combustion occurs in the conductive mode. Comparison of the combustion velocities of granular mixtures containing Ti powder with particles of a characteristic size of 60 μm in the absence and presence of gas filtration through the sample indicates the transition of combustion to the convective regime. The necessary and sufficient conditions for the transition from conductive to convective combustion are formulated, which makes it possible to determine the composition of the mixture whose combustion occurs in the boundary region. In mixtures based on Ti with a particle size of 60 μm, the conductive combustion regime is observed during the combustion of granules 0.6 mm in size and a mixture with <i>X</i> = 30% of granules 1.7 mm in size. For mixtures with <i>X</i> = 0–20% with granules 1.7 mm in size, burning in the convective regime, the interfacial heat transfer coefficients are evaluated using the experimental data. Their values are more than an order of magnitude higher than the theoretical ones. The XRD results of the combustion products showed that in order to obtain synthesis products without side phases of intermetallic compounds, it is necessary to use finely dispersed titanium powder.</p>","PeriodicalId":768,"journal":{"name":"Russian Journal of Physical Chemistry B","volume":"18 4","pages":"952 - 964"},"PeriodicalIF":1.4,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142214440","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}