Труды сотрудников ИВМ СО РАН

[Текст] : статья / I.I. Ryzhkov // Lournal of Applied Mechanics and Technical Physics. - 2011. - Vol. 52, Iss. 4. - p. 560-570DOI 10.1134/S0021894411040080 . -
Аннотация: A model of vibrational convection of a binary mixture with the thermodiffusion effect is considered. The symmetries of model equations are found, depending on the values of physical parameters. A partially invariant solution, which describes separation of the binary mixture in a thermodiffusion column, is constructed and studied. The influence of streamwise vibrations on the flow regime and separation of the mixture is investigated.

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Доп.точки доступа:
Stepanova, I.V.; Степанова, Ирина Владимировна; Рыжков, Илья Игоревич

[Text] / D. I. Kubyshkina [et al.] // J. Geophys. Res-Space Phys. - 2014. - Vol. 119, Is. 4. - P. 3002-3015, DOI 10.1002/2013JA019477. - Cited References: 32. - We thank C. W. Carlson and J. P. McFadden for use of THEMIS ESA data; K. H. Glassmeier, U. Auster, and W. Baumjohann for the use of FGM data provided under the lead of the Technical University of Braunschweig and with financial support through the German Ministry for Economy and Technology and the German Center for Aviation and Space (DLR) under contract 50 OC 0302. The work was partly supported by SPbU grant 11.38.84.12, by RFBR grants 12-05-00152-a and 12-05-00918-a, and by the grant for support of leading Scientific schools 2836.2014.5. The work of S. Dubyagin and N. Ganushkina was partly supported by the Academy of Finland. This work was supported by the Austrian Science Fund (FWF): I193-N16. N. V. E acknowledges the support by the International Space Science Institute (ISSI, Switzerland) and discussions within the ISSI Team 214 on Flow-Driven Instabilities of the Sun-Earth System. The research has received funding also from the European Union Seventh Framework Programme [FP7/2007-2013] under grant agreement 269198-Geoplasmas (Marie Curie International Research Staff Exchange Scheme) and 218816 (SOTERIA project). . - ISSN 2169-9380. - ISSN 2169-9402РУБ Astronomy & Astrophysics

Аннотация: Flapping waves are most noticeable large-scale perturbations of the magnetotail current sheet, whose nature is still under discussion. They represent rather slow (an order of magnitude less than typical Alfven speed) waves propagating from the center of the sheet to its flanks with a typical speed of 20-60 km/s, amplitude of 1-2 R-e and quasiperiod of 2-10 min. The double-gradient MHD model, which was elaborated in Erkaev et al. (2007) predicts two (kink and sausage) modes of the flapping waves with differences in their geometry and propagation velocity, but the mode structure is hard to resolve observationally. We investigate the possibility of mode identification by observing the rotation of magnetic field and plasma velocity vectors from a single spacecraft. We test theoretical results by analyzing the flapping oscillations observed by Time History of Events and Macroscale Interactions during Substorms spacecraft and confirm that character of observed rotation is consistent with kink mode determination made by using multispacecraft methods. Also, we checked how the existence of some obstructive conditions, such as noise, combined modes, and multiple sources of the flapping oscillations, can affect on the possibility of the modes separation with suggested method.

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Держатели документа:
ИВМ СО РАН

Доп.точки доступа:
Kubyshkina, D.I.; Sormakov, D.A.; Sergeev, V.A.; Semenov, V.S.; Erkaev, N.V.; Еркаев, Николай Васильевич; Kubyshkin, I.V.; Ganushkina, N.Y.; Dubyagin, S.V.; German Ministry for Economy and Technology; German Center for Aviation and Space (DLR) [50 OC 0302]; SPbU [11.38.84.12]; RFBR [12-05-00152-a, 12-05-00918-a]; grant for support of leading Scientific schools [2836.2014.5]; Academy of Finland; Austrian Science Fund (FWF) [I193-N16]; International Space Science Institute (ISSI, Switzerland); European Union [269198, 218816]

/ I. I. Ryzhkov, I. V. Stepanova // Int. J. Heat Mass Transf. - 2015. - Vol. 86. - P268-276, DOI 10.1016/j.ijheatmasstransfer.2015.02.069 . - ISSN 0017-9310
Аннотация: The stationary heat transfer and Soret separation of a binary mixture between parallel plates with different constant temperatures is studied allowing for variable transport properties. The mixture is described by non-linear one-dimensional equations of heat and mass transfer, where the density, thermal conductivity, and Soret coefficient depend on temperature and concentration. A general procedure for integrating these equations is proposed. The problem is reduced to the ordinary differential equation of first order, which describes the trajectory of the system in the concentrationerature plane, and implicit dependence of temperature on space coordinate. It is shown that the solution for concentration is unique if the density and thermal conductivity do not depend on concentration. Analytical solutions of the problem are derived in a number of cases, while the most general case is treated numerically. The non-linear temperature and concentration profiles in different binary mixtures (aqueous solutions, colloidal suspensions, polymer blend) are constructed and analyzed. A procedure for extracting the dependence of Soret coefficient on temperature and concentration from the experimentally measured thermal and compositional profiles is suggested. © 2015 Elsevier Ltd.All rights reserved.

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Держатели документа:
Institute of Computational Modelling SB RASAkademgorodok,Krasnoyarsk, Russian Federation
ИВМ СО РАН

Доп.точки доступа:
Stepanova, I.V.; Степанова, Ирина Владимировна; Рыжков, Илья Игоревич

[Text] / E. P. Magdenko // J. Appl. Mech. Tech. Phys. - 2016. - Vol. 57, Is. 1. - P13-19, DOI 10.1134/S002189441601003X. - Cited References:8. - This work was supported by Integration Project of the Siberian Branch of the Russian Academy of Sciences No. 38 and the Russian Foundation for Basic Research (Grant No. 14-01-00067). . - ISSN 0021-8944. - ISSN 1573-8620РУБ Mechanics + Physics, Applied

Аннотация: This paper considers a liquid in a finite-size cylinder in which Marangoni instability occurs. The upper boundary of the liquid is free and deformable. The problem of the occurrence of convection in a cylindrical container is solved using the method of separation of variables. A homogeneous differential equation of the sixth order with constant coefficients and complex boundary conditions is obtained. An analytical expression for critical Marangoni numbers is derived for the case of monotonic perturbations. The case is considered where the liquid in the cylinder is weightless.

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Russian Acad Sci, Inst Computat Modeling, Siberian Branch, Krasnoyarsk 660036, Russia.

Доп.точки доступа:
Magdenko, E. P.; Integration Project of the Siberian Branch of the Russian Academy of Sciences [38]; Russian Foundation for Basic Research [14-01-00067]

/ S. V. Kozlova, I. I. Ryzhkov // Phys. Fluids. - 2016. - Vol. 28, Is. 11, DOI 10.1063/1.4966640 . - ISSN 1070-6631
Аннотация: This work studies the stationary separation of a multicomponent mixture in a thermogravitational column (TGC). The existing theory for a flat-plate column is extended to the case of a cylindrical column. The equations of motion and heat/mass transfer are written in cylindrical coordinates to take into account the impact of the cylinders curvature and the ratio of their radii on the separation process. To characterize the impact of each component on convective motion induced by thermal diffusion, the dimensionless separation ratios are used. A multicomponent system as a whole is described by the net separation ratio. The approximation neglecting vertical diffusion in the column is employed and conditions for its validity are analyzed. The profiles of velocity, temperature, composition, and density in the column with a multicomponent mixture are found and their dependence on the separation ratios and the ratio of cylinders radii is analyzed. The vertical separation is described by the solutal Rayleigh numbers, which are proportional to the vertical concentration gradients. It is shown that the key relation of TGC theory, which relates the net solutal Rayleigh number to the net separation ratio, essentially depends on the ratio of cylinders radii. The working formulas for the thermal diffusion coefficients are derived and the importance of forgotten effect is discussed. It is found that the vertical separation in the column increases with decreasing the ratio of inner and outer cylinders radii. A detailed comparison of results with the case of a flat-plate column is performed. Example of a ternary hydrocarbon mixture is analyzed on the basis of obtained solution and numerical simulation. © 2016 Author(s).

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Держатели документа:
Institute of Computational Modelling SB RAS, 50/44 Akademgorodok, Krasnoyarsk, Russian Federation
Siberian Federal University, 79 Svobodny pr., Krasnoyarsk, Russian Federation

Доп.точки доступа:
Ryzhkov, I.I.; Рыжков, Илья Игоревич; Козлова, Софья Владимировна

/ V. K. Andreev // Bull. South Ural State Univ. Ser. Math. Model. Program. Comput. Softw. - 2016. - Vol. 9, Is. 4. - С. 5-16, DOI 10.14529/mmpl60401 . - ISSN 2071-0216
Аннотация: An inverse initial boundary value problem for a linear parabolic equation that arises as a result of mathematical modelling of 2D creeping motion of viscous liquid in a flat channel is considered. The unknown function of time is added in the right part of equation and can be found from additional condition of integral overdetermination. This problem has two different integral identities, permitting to obtain a priori estimates of solutions in uniform metric and to proof the uniqueness theorem. Under some restrictions on input data the solution is constructed as a series in the special basis. For this purpose the problem is reduced by differentiation with respect to the spatial variable to a direct non-classic problem with two integral conditions instead of ordinary ones. The new problem is solved by separation of variables, which allows one to find the unknown functions in the form of rapidly converging series. Another method for solving the initial problem is to reduce the problem to the loaded equation and to state the first initial boundary value problem for this equation. In its turn, this problem is reduced to one-dimensional in time Volterra operator equation with a special kernel. It is proved that it has a series solution. Some auxiliary formulas which are useful for the numerical solution of this equation by the Laplace transform are obtained. Sufficient conditions under which the solution with increasing time converges to steady regime by exponential law are established.

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Institute Computational Modelling, SB RAS, Krasnoyarsk, Russian Federation

Доп.точки доступа:
Andreev, V. K.

/ I. I. Ryzhkov, S. V. Kozlova // Eur. Phys. J. E. - 2016. - Vol. 39, Is. 12, DOI 10.1140/epje/i2016-16130-6 . - ISSN 1292-8941
Аннотация: Abstract.: The stationary and transient Soret separation in a binary mixture with a consolute critical point is studied theoretically. The mixture is placed between two parallel plates kept at different temperatures. A polymer blend is used as a model system. Analytical solutions are constructed to describe the stationary separation in a binary mixture with variable Soret coefficient. The latter strongly depends on temperature and concentration and enhances near a consolute critical point due to reduced diffusion. As a result, a large concentration gradient is observed locally, while much smaller concentration variations are found in the rest of the layer. It is shown that complete separation can be obtained by applying a small temperature difference first, waiting for the establishment of stationary state, and then increasing this difference again. In this case, the critical temperature lies between hot and cold wall temperatures, while the mixture still remains in the one-phase region. When the initial (mean) temperature or concentration are shifted away from the near-critical values, the separation decreases. The analysis of transient behavior shows that the Soret separation occurs much faster than diffusion to the homogeneous state when the initial concentration is close to the critical one. It happens due to the decrease (increase) of the local relaxation time during the Soret (Diffusion) steps. The transient times of these steps become comparable for small temperature differences or off-critical initial concentrations. An unusual (non-exponential) separation dynamics is observed when the separation starts in the off-critical domain, and then enhances greatly when the system enters into the near-critical region. It is also found that the transient time decreases with increasing the applied temperature difference. Graphical abstract: [Figure not available: see fulltext.] © 2016, EDP Sciences, SIF, Springer-Verlag Berlin Heidelberg.

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Держатели документа:
Institute of Computational Modelling SB RAS, Akademgorodok, Krasnoyarsk, Russian Federation
Siberian Federal University, Svobodny 79, Krasnoyarsk, Russian Federation

Доп.точки доступа:
Kozlova, S.V.; Kozlova S.V.; Рыжков, Илья Игоревич

/ V. K. Andreev // Bull. South Ural State U. Ser.-Math Model Program Comput. - 2016. - Vol. 9, Is. 4. - С. 5-16, DOI 10.14529/mmp160401. - Cited References:16 . - ISSN 2071-0216. - ISSN 2308-0256РУБ Mathematics, Applied

Аннотация: An inverse initial boundary value problem for a linear parabolic equation that arises as a result of mathematical modelling of 2D creeping motion of viscous liquid in a flat channel is considered. The unknown function of time is added in the right part of equation and can be found from additional condition of integral overdetermination. This problem has two different integral identities, permitting to obtain a priori estimates of solutions in uniform metric and to proof the uniqueness theorem. Under some restrictions on input data the solution is constructed as a series in the special basis. For this purpose the problem is reduced by differentiation with respect to the spatial variable to a direct non-classic problem with two integral conditions instead of ordinary ones. The new problem is solved by separation of variables, which allows one to find the unknown functions in the form of rapidly converging series. Another method for solving the initial problem is to reduce the problem to the loaded equation and to state the first initial boundary value problem for this equation. In its turn, this problem is reduced to one-dimensional in time Volterra operator equation with a special kernel. It is proved that it has a series solution. Some auxiliary formulas which are useful for the numerical solution of this equation by the Laplace transform are obtained. Sufficient conditions under which the solution with increasing time converges to steady regime by exponential law are established.

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Держатели документа:
Inst Computat Modelling SB RAS, Krasnoyarsk, Russia.

Доп.точки доступа:
Andreev, V. K.

[Текст] : статья / Виктор Константинович Андреев // Вестник Южно-Уральского государственного университета. Серия: Математическое моделирование и программирование. - 2016. - Т. 9, № 4. - С. 5-16, DOI 10.14529/mmp160401 . - ISSN 2071-0216
   Перевод заглавия: On the Solution of an Inverse Problem Simulating Two-Dimensional Motion of a Viscous Fluid

УДК	517.956.27

Аннотация: Рассматривается обратная начально-краевая задача для линейного параболического уравнения, которая возникает при математическом моделировании двумерных ползущих движений вязкой жидкости в плоском канале. Неизвестная функция времени входит в правую часть уравнения аддитивно и находится из дополнительного условия интегрального переопределения. Поставленная задача имеет два разных интегральных тождества, которые позволяют получить априорные оценки решения в равномерной метрике и доказать теорему единственности. При некоторых ограничениях на входные данные решение построено в виде ряда по специальному базису. Для этого задача путем дифференцирования по пространственной переменной сводится к прямой неклассической задаче с двумя интегральными условиями вместо обычных краевых. Новая задача решается методом разделения переменных, позволяющим найти неизвестные функции в виде быстро сходящихся рядов. Другой, стандартный, метод решения исходной задачи состоит в сведении ее к нагруженному уравнению и первой начально-краевой задаче для него. В свою очередь, эта задача сведена к одномерному по времени операторному уравнению Вольтерры со специальным ядром. Доказано, что оно имеет решение в виде ряда. Установлены некоторые вспомогательные формулы, полезные при численном решении этого уравнения методом преобразования Лапласа. Установлены достаточные условия, при которых решение с ростом времени выходит на стационарный режим по экспоненциальному закону.
An inverse initial boundary value problem for a linear parabolic equation that arises as a result of mathematical modelling of 2D creeping motion of viscous liquid in a flat channel is considered. The unknown function of time is added in the right part of equation and can be found from additional condition of integral overdetermination. This problem has two different integral identities, permitting to obtain a priori estimates of solutions in uniform metric and to proof the uniqueness theorem. Under some restrictions on input data the solution is constructed as a series in the special basis. For this purpose the problem is reduced by differentiation with respect to the spatial variable to a direct non-classic problem with two integral conditions instead of ordinary ones. The new problem is solved by separation of variables, which allows one to find the unknown functions in the form of rapidly converging series. Another method for solving the initial problem is to reduce the problem to the loaded equation and to state the first initial boundary value problem for this equation. In its turn, this problem is reduced to one-dimensional in time Volterra operator equation with a special kernel. It is proved that it has a series solution. Some auxiliary formulas which are useful for the numerical solution of this equation by the Laplace transform are obtained. Sufficient conditions under which the solution with increasing time converges to steady regime by exponential law are established.

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Держатели документа:
Институт вычислительного моделирования СО РАН

Доп.точки доступа:
Андреев, Виктор Константинович; Andreev V.K.

[Текст] : статья / Софья Владимировна Козлова, Илья Игоревич Рыжков // Образовательные ресурсы и технологии. - 2016. - № 2. - С. 320-324 . - ISSN 2312-5500
   Перевод заглавия: Detemination of the characteristic time of a binary mixture separation in a cylindrical thermogravitational column

УДК

532.529.2

51-73

Аннотация: В данной работе рассмотрен нестационарный процесс разделения бинарной смеси в цилиндрической термодиффузионной колонне, для которого определена зависимость времени установления стационарного процесса от отношения радиусов цилиндров. При отношении радиусов, близком к единице, значение времени соответствует случаю плоской колонны
In this paper, the unsteady-state binary mixture separation in a cylindrical thermogravitational column is considered. For this process, the dependence of the characteristic time of establishing the steady-state separation on the ratio of the cylinders radii is obtained. When the ratio is close to unity, the characteristic time corresponds to that of a flat-plate column

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Держатели документа:
Институт Вычислительного моделирования СО РАН, Сибирский Федеральный университет

Доп.точки доступа:
Рыжков, Илья Игоревич; Ryzhkov I.I.; Kozlova S.V.

[Текст] : статья / Евгений Петрович Магденко // Прикладная механика и техническая физика. - 2016. - Т. 57, № 1. - С. 16-23, DOI 10.15372/PMTF20160103 . - ISSN 0869-5032
   Перевод заглавия: Marangoni Convection in a Finite-Size Cylinder

УДК	532.61.096

Аннотация: Рассмотрена находящаяся в цилиндре конечного размера жидкость, в которой возникает неустойчивость Марангони. Верхняя граница жидкости свободна и деформируема. С использованием метода разделения переменных решена задача о возникновении конвекции в цилиндрическом контейнере. Получено однородное дифференциальное уравнение шестого порядка с постоянными коэффициентами и сложными граничными условиями. Для случая монотонных возмущений получено аналитическое выражение для критических чисел Марангони. Рассмотрен случай, когда жидкость в цилиндре находится в состоянии невесомости.
This paper considers a liquid in a finite-size cylinder in which Marangoni instability occurs. The upper boundary of the liquid is free and deformable. The problem of the occurrence of convection in a cylindrical container is solved using the method of separation of variables. A homogeneous differential equation of the sixth order with constant coefficients and complex boundary conditions is obtained. In the case of monotonic perturbations, an analytical expression for critical Marangoni numbers is derived. The case of a weightless liquid in the cylinder is considered.

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Держатели документа:
Институт вычислительного моделирования СО РАН

Доп.точки доступа:
Magdenko E.P.

[Text] : abstract / I. I. Ryzhkov, M. I. Medvedeva // 12th International Meeting on Thermal Diffusion : book of abstracts. - Madrid, 2016. - P106


Доп.точки доступа:
Medvedeva, M.I.; Рыжков, Илья Игоревич

[Text] : abstract / I. I. Ryzhkov, A. V. Minakov // 12th International Meeting on Thermodiffusion : book of abstracts. - Madrid, 2016. - P74


Доп.точки доступа:
Minakov, A.V.; Минаков, Андрей Викторович; Рыжков, Илья Игоревич

[Text] : abstract / S. V. Kozlova, I. I. Ryzhkov // 12th International Meeting on Thermodiffusion : book of abstracts. - Madrid, 2016. - P76


Доп.точки доступа:
Ryzhkov, I.I.; Рыжков, Илья Игоревич; Козлова, Софья Владимировна

/ D. V. Lebedev [et al.] // Pet. Chem. - 2017. - Vol. 57, Is. 4. - P306-317, DOI 10.1134/S096554411704003X. - Cited References:52. - This work was supported by the Russian Science Foundation, grant no. 15-19-10017. Instrumental analysis of the materials was performed in the Shared Equipment Center at the Krasnoyarsk Scientific Center, Siberian Branch of the Russian Academy Sciences. . - ISSN 0965-5441. - ISSN 1555-6239РУБ Chemistry, Organic + Chemistry, Physical + Energy & Fuels + Engineering,

Аннотация: A novel type of ion-selective membranes based on Nafen(TM) alumina nanofibers coated with carbon is proposed. The membranes are produced by filtration of a Nafen nanofiber suspension through a porous support followed by drying and sintering. A thin carbon layer (up to 2 nm) is deposited on the nanofibers by chemical vapor deposition (CVD). Its formation is confirmed by the results of Raman spectroscopy and visually observed in TEM images. According to low temperature nitrogen adsorption experiments, the formation of carbon layer leads to decreasing pore size (the maximum of pore size distribution shifts from 28 to 16 nm) and the corresponding decrease of porosity (from 75 to 62%) and specific surface area (from 146 to 107 m(2)g(-1)). The measurement of membrane potential in an electrochemical cell has shown that the deposition of carbon on the membrane results in high ionic selectivity. In an aqueous KCl solution, the membranes display high anion selectivity with anion and cation transference numbers of 0.94 and 0.06, respectively. The fixed-charge density of membrane has been determined by fitting the experimental data using the Teorell-Meyer-Sievers model. It has been found that the membrane fixed-charge density increases with increasing electrolyte concentration. Possible applications of the membranes produced include nanofiltration, ultrafiltration, and separation of charged species in mixtures. The formation of a conductive carbon layer on the pore surface can be employed for fabricating membranes with switchable ion-transport selectivity.

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Держатели документа:
Russian Acad Sci, Inst Computat Modeling, Siberian Branch, Krasnoyarsk, Russia.
Russian Acad Sci, Siberian Branch, Mol Elect Dept, Krasnoyarsk Sci Ctr, Krasnoyarsk, Russia.
Natl Res Univ Elect Technology MIET, Moscow, Russia.
Russian Acad Sci, Siberian Branch, Inst Chem & Chem Technol, Krasnoyarsk, Russia.

Доп.точки доступа:
Lebedev, D.V.; Лебедев Д.В.; Shiverskiy, A. V.; Simunin, M. M.; Solodovnichenko, V.S.; Солодовниченко В.С.; Parfenov, V. A.; Bykanova, V. V.; Khartov, S. V.; Ryzhkov, I.I.; Рыжков, Илья Игоревич; Russian Science Foundation [15-19-10017]

[Текст] : статья / Д. В. Лебедев [и др.] // Мембраны и мембранные технологии. - 2017. - Т. 7, № 2. - С. 86-98, DOI 10.1134/S2218117217020031 . - ISSN 2218-1172
Аннотация: Предложен новый тип керамических мембран с ионной селективностью на основе нановолокон оксида алюминия (NafenTM), покрытых слоем углерода. Синтез мембран осуществляется методом вакуумной фильтрации коллоидного раствора волокон Nafen с последующим термическим отжигом и нанесением углеродного слоя методом химического осаждения из газовой фазы (chemical vapor deposition, CVD). Данные просвечивающей электронной микроскопии и спектроскопии комбинационного рассеяния подтверждают формирование углеродного слоя толщиной до 2 нм на нановолокнах. По данным низкотемпературной адсорбции азота, это приводит к уменьшению размера пор (максимум функции распределения смещается от 28 к 16 нм) и соответственному снижению пористости (с 75 до 62%) и удельной поверхности мембраны (с 146 до 107 м2 г–1). С помощью потенциометрического метода установлено, что нанесение углеродного слоя на мембраны из волокон Nafen придает им выраженные ионоселективные свойства. Измерения в водном растворе KCl показали, что полученные мембраны являются анион-селективными с числами переноса 0.94 для аниона и 0.06 для катиона. Определена плотность фиксированного заряда мембран путем аппроксимации экспериментальных данных моделью Теорелла–Мейера–Сиверса. Показано, что плотность заряда возрастает с увеличением концентрации электролита. Полученные мембраны могут быть применены в области нано- и ультрафильтрации, а также для разделения заряженных компонентов смесей. Нанесение проводящего углеродного слоя на поверхность пор является перспективным для создания мембран с управляемой ионной селективностью.
A novel type of ion-selective membranes based on NafenTM alumina nanofibers covered with carbon is proposed. The membranes are produced by filtration of Nafen nanofiber suspension through a porous support followed by drying and sintering. A thin carbon layer (up to 2 nm) is deposited on the nanofibers with the help of chemical vapor deposition (CVD). Its formation is confirmed by the results of Raman spectroscopy and visually observed in TEM images. According to low temperature nitrogen adsorption experiments, the formation of carbon layer leads to decreasing pore size (the maximum of pore size distribution shifts from 28 to 16 nm) and the corresponding decrease of porosity (from 75 to 62%) and specific surface area (from 146 to 107 m2 g–1). The measurement of membrane potential in an electrochemical cell shows that the deposition of carbon on the membrane results in high ionic selectivity. In an aqueous KCl solution, the membranes display high anion–selectivity with transference numbers 0.94 for anion and 0.06 for cation. The fixed charge density of membrane is determined by fitting the experimental data with the help of Teorell–Meyer–Sievers model. It is found that the density of fixed membrane charge increases with increasing the electrolyte concentration. The potential applications of produced membranes include nano- and ultrafiltration as well as separation of charged species in mixtures. The formation of conductive carbon layer on the pore surface can be employed for producing membranes with switchable ion-transport selectivity. Keywords: alumina nanofiber, membrane, chemical vapor deposition, carbon, membrane potential measurement, ionic permselectivity, Teorell–Meyer–Sievers model

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Держатели документа:
Институт вычислительного моделирования СО РАН, Академгородок 50-44, Красноярск, Россия
Институт химии и химической технологии СО РАН, Академгородок 50-24, Красноярск, Россия
Красноярский научный центр СО РАН, Академгородок 50, Красноярск, Россия
Национальный исследовательский университет “МИЭТ”, Площадь Шокина, 1, Зеленоград, Москва, Россия

Доп.точки доступа:
Лебедев, Д.В.; Шиверский, А.В.; Симунин, М.М.; Солодовниченко, В.С.; Парфенов, В.А.; Быканова, В.В.; Хартов, С.В.; Рыжков, И.И.

/ V. S. Solodovnichenko [et al.] // Adv. Eng. Mater. - 2017. - Vol. 19, Is. 11. - Ст. 1700244, DOI 10.1002/adem.201700244. - Cited References:60. - This work is supported by the Russian Science Foundation, Project 15-19-10017. The physicochemical analysis of materials was carried out on equipment of Krasnoyarsk Scientific Center of Shared Facilities SB RAS. . - ISSN 1438-1656. - ISSN 1527-2648РУБ Materials Science, Multidisciplinary

Аннотация: The authors propose a novel type of ion-selective membranes, which combine the advantages of ceramic nanofibrous media with good electrical conductivity. The membranes are produced from Nafen alumina nanofibers (diameter around 10nm) by filtration of nanofiber suspension through a porous support followed by drying and sintering. Electrical conductivity is achieved by depositing a thin carbon layer on the nanofibers by chemical vapor deposition (CVD). Raman and FTIR spectroscopy, X-ray fluorescence analysis, and TEM are used to confirm the carbon structure formation. The deposition of carbon leads to decreasing porosity (from 75 to 62%) and specific surface area (from 146 to 107m(2) g(-1)) of membranes, while the pore size distribution maximum shifts from 28 to 16nm. Measurements of membrane potential in an electrochemical cell show that the carbon coated membranes acquire high ionic selectivity (transference numbers 0.94 for anion and 0.06 for cation in aqueous KCl). Fitting the membrane potential data by the Teorell-Meyer-Sievers model shows that the fixed membrane charge increases proportionally with increasing electrolyte concentration. The carbon coated membranes are ideally polarizable for applied voltages from -0.5 to +0.8V. The potential applications of produced membranes include nano- and ultrafiltration, separation of charged species, and switchable ion-transport selectivity.

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Держатели документа:
Inst Computat Modeling SB RAS, Akademgorodok 50-44, Krasnoyarsk, Russia.
Fed Res Ctr KSC SB RAS, Akademgorodok 50, Krasnoyarsk, Russia.
Natl Res Univ Elect Technol MIET, Shokin Sq 1, Moscow, Russia.
Inst Chem & Chem Technol SB RAS, Akademgorodok 50-24, Krasnoyarsk, Russia.

Доп.точки доступа:
Solodovnichenko, Vera S.; Lebedev, Denis V.; Bykanova, Victoria V.; Shiverskiy, Alexey V.; Simunin, Mikhail M.; Parfenov, Vladimir A.; Ryzhkov, Ilya I.; Russian Science Foundation [15-19-10017]

/ I. I. Ryzhkov [et al.] // J. Membr. Sci. - 2018. - Vol. 549. - P616-630, DOI 10.1016/j.memsci.2017.11.073. - Cited References:69. - This work is supported the Russian Science Foundation, Project 15-19-10017. The physicochemical analysis of materials was carried out on the equipment of Krasnoyarsk Scientific Center of Shared Facilities SB RAS. . - ISSN 0376-7388. - ISSN 1873-3123РУБ Engineering, Chemical + Polymer Science

Аннотация: We report a new mechanism for the generation of membrane potential in polarizable nanoporous membranes separating electrolytes with different concentrations. The electric field generated by diffusion of ions with different mobilities induces a non-uniform surface charge, which results in charge separation inside the nanopore. The corresponding Donnan potentials appear at the pore entrance and exit leading to a dramatic enhancement of membrane potential in comparison with an uncharged non-polarizable membrane. At high concentration contrast, the interaction between electric field and uncompensated charge at a low concentration side results in the development of electrokinetic vortices. The theoretical predictions are based on the Space-Charge model, which is extended to nanopores with polarizable conductive surface for the first time. This model is validated against full Navier-Stokes, Nernst-Planck, and Poisson equations, which are solved in a high aspect ratio nanopore connecting two reservoirs. The experimental measurements of membrane potential of dielectric and conductive membranes in KCl and NaCl aqueous solutions confirm the theoretical results. The membranes are prepared from Nafen nanofibers with similar to 10 nm in diameter and modified by depositing a conductive carbon layer. It is shown theoretically that the membrane potential enhancement becomes greater with decreasing the electrolyte concentration and pore radius. A high sensitivity of membrane potential to the ratio of ion diffusion coefficients is demonstrated. The described phenomenon may find applications in precise determination of ion mobilities, electrochemical and bio-sensing, as well as design of nanofluidic and bioelectronic devices.

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Держатели документа:
Fed Res Ctr KSC SB RAS, Inst Computat Modelling SB RAS, Akademgorodok 50-44, Krasnoyarsk 660036, Russia.
Siberian Fed Univ, Svobodny 79, Krasnoyarsk 660041, Russia.

Доп.точки доступа:
Ryzhkov, Ilya I.; Lebedev, Denis V.; Solodovnichenko, Vera S.; Minakov, Andrey V.; Simunin, Mikhail M.; Russian Science Foundation [15-19-10017]

[Text] : доклад, тезисы доклада / Sofia Kozlova [et al.] // The Joint Conference of the 7th International Symposium on Physical Sciences in Space (ISPS-7) & 25th European Low Gravity Research Association Biennial Symposium and General Assembly (ELGRA-25) : abstract Book. - Juan-les-Pins : European Space Agency, 2017. - P68

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Держатели документа:
Krasnoyarsk Science Centre of the Siberian Branch of Russian Academy of Science
Mech. and Manufacturing Dept, MGEP Mondragon Goi Eskola Politeknikoa

Доп.точки доступа:
Kozlova, Sofia; Lapeira, E.; Ryzhkov, Ilya; Bou - Ali, M. M.; The Joint Conference of the 7th International Symposium on Physical Sciences in Space (ISPS-7); 25th European Low Gravity Research Association Biennial Symposium and General Assembly (ELGRA-25)(2017 ; 02.10 - 06.10 ; Juan-les-Pins)
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/ S. V. Kozlova, I. I. Ryzhkov // Int. J. Heat Mass Transf. - 2018. - Vol. 126. - P660-669, DOI 10.1016/j.ijheatmasstransfer.2018.05.086 . - ISSN 0017-9310
Аннотация: This work deals with the transient separation of a multicomponent mixture in a cylindrical thermogravitational column. The model describing the evolution of separation in vertical direction is derived and solved analytically. It is assumed that the profiles of velocity and temperature in radial direction are established and the forgotten effect as well as vertical diffusion in the column are ignored. The dependence of separation and characteristic transient time on the ratio of inner and outer cylinders radii ? is obtained. The transient time tends to diffusion time along the column height when ? approaches zero, while it reduces to the transient time for a flat–plate column when ? approaches unity. The analytical results are compared with two–dimensional numerical simulation for binary and ternary mixtures, and a good agreement is observed. It is concluded that for typical liquid mixtures, the decrease of radii ratio between inner and outer cylinders results in a slight increase of separation and in a significant increase of transient time. © 2018 Elsevier Ltd

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Держатели документа:
Institute of Computational Modelling SB RAS, 50/44 Akademgorodok, Krasnoyarsk, Russian Federation
Siberian Federal University, 79 Svobodny pr., Krasnoyarsk, Russian Federation

Доп.точки доступа:
Kozlova, S. V.; Ryzhkov, I. I.