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Найдено документов в текущей БД: 194
   В3
   Г67

    Особенности переходных процессов в динамических системах
[Электронный ресурс]. - Электрон. дан. (499 Кб) : диссертации на соискание ученой степени кандидата-физико математических наук (перевод на английский язык) / А.Н. Горбань. - Электрон. дан. (499 Кб). - [Б. м. : б. и.], 1997. - Б. ц.

Аннотация: The paper gives the systematic analysis of singularities of transition processes in general dynamical systems. Dynamical systems depending on parameter are studied. A system of relaxation times is constructed. Each relaxation time depends on three variables: initial conditions, parameters k of the system and accuracy ? of relaxation. This system of times contains: the time before the first entering of the motion into ?-neighbourhood of the limit set, the time of final entering in this neighbourhood and the time of stay of the motion outside the ?-neighbourhood of the limit set. The singularities of relaxation times as functions of (x0; k) under fixed ? are studied. A classification of different bifurcations (explosions) of limit sets is performed. The bifurcations fall into those with appearance of new limit points and bifurcations with appearance of new limit sets at finite distance from the existing ones. The relations between the singularities of relaxation times and bifurcations of limit sets are studied. The peculiarities of dynamics which entail singularities of transition processes without bifurcations are described as well. The peculiarities of transition processes under perturbations are studied. It is shown that the perturbations simplify the situation: the interrelations between the singularities of relaxation times and other peculiarities of dynamics for general dynamical system under small perturbations are the same as for smooth two-dimensional structural stable systems.

http://icm.krasn.ru/refextra.php?id=2806


Доп.точки доступа:
Gorban A.N.
Свободных экз. нет
   В3
   A80

    Instability of the magnetopause with a finite curvature radius and velocity shear
[Text] : статья / I.L. Arshukova, N.V. Erkaev, H.K. Biernat // International journal of geomagnetism and aeronomy. - 2002. - Vol. 3, № 1. - p. 27–34

Аннотация: This article deals with the magnetohydrodynamic instability of the high magnetic shear magnetopause, which is considered to be a thin layer with a constant curvature radius and plasma velocity shear. In our model, the magnetic field and plasma density are assumed to be piecewise constant in three regions: in the magnetosphere adjacent to the magnetopause, in the magnetosheath, and inside a thin layer associated with the magnetopause. The plasma parameters and the magnetic field are assumed to obey the ideal incompressible magnetohydrodynamics. A Fourier analysis is used to calculate small perturbations of magnetic field and plasma parameters near the magnetopause in a linear approximation. The instability growth rate is obtained as a function of the angle between the velocity vector and the geomagnetic field direction for different plasma bulk speeds, wave numbers and curvature radii. The resulting instability is a mixture of interchange and Kelvin-Helmholtz instabilities on a surface with a nonzero curvature. The instability growth rate is an increasing function of the tangential velocity component perpendicular to the magnetic field. On the other hand, the growth rate is a decreasing function of the velocity component along the magnetic field.

http://icm.krasn.ru/refextra.php?id=2427,
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Держатели документа:
ИВМ СО РАН : 660036, Красноярск, Академгородок, 50, стр.44

Доп.точки доступа:
Erkaev, N.V.; Еркаев, Николай Васильевич; Biernat, H.K.; Аршукова И.Л.
   В3
   E68

    Effects of MHD shocks propagating along magnetic flux tubes in a dipole magnetic field
[Text] : статья / N.V. Erkaev, V.A. Shaidurov, V.S. Semenov, H.K. Biernat // Nonlinear Processes in Geophysics. - 2002. - Vol. 9. - p. 163-172

Аннотация: Variations of the plasma pressure in a magnetic flux tube can produce MHD waves evolving into shocks. In the case of a low plasma beta, plasma pressure pulses in the magnetic flux tube generate MHD slow shocks propagating along the tube. For converging magnetic field lines, such as in a dipole magnetic field, the cross section of the mag-netic flux tube decreases enormously with increasing mag-netic field strength. In such a case, the propagation of MHD waves along magnetic flux tubes is rather different from that in the case of uniform magnetic fields. In this paper, the propagation of MHD slow shocks is studied numerically us-ing the ideal MHD equations in an approximation suitable for a thin magnetic flux tube with a low plasma beta. The results obtained in the numerical study show that the jumps in the plasma parameters at the MHD slow shock increase greatly while the shock is propagating in the narrowing mag-netic flux tube. The results are applied to the case of the interaction between Jupiter and its satellite Io, the latter be-ing considered as a source of plasma pressure pulses.

http://icm.krasn.ru/refextra.php?id=2437,
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Держатели документа:
ИВМ СО РАН : 660036, Красноярск, Академгородок, 50, стр.44

Доп.точки доступа:
Shaidurov, V.A.; Шайдуров В.А.; Semenov, V.S.; Семенов В. С.; Biernat, H.K.; Еркаев, Николай Васильевич
   В3
   E68

    Ideal Magnetohydrodynamic Flow Around a Blunt Body under Anisotropic Pressure
[Text]. - Electronic data (106 Kb)
. - Режим доступа: http://icm.krasn.ru/refextra.php?id=1472. - Электрон. версия печ. публикации . - Режим доступа: http://library.krasn.ru/trudy/2000/1472erkaev_PHP03413_eng.pdf (Полный текст) : статья / Erkaev N.V., Biernat H.K., Farrugia C.J. - Electronic data (106 Kb) // Physics of Plasmas. - 2000. - Vol. 7, № 7. - p. 3413-3420
ГРНТИ

Аннотация: The plasma flow past a blunt obstacle in an ideal magnetohydrodynamic ~MHD! model is studied, taking into account the tensorial nature of the plasma pressure. Three different closure relations are explored and compared with one another. The first one is the adiabatic model proposed by Chew, Goldberger, and Low. The second closure is based on the mirror instability criterion, while the third depends on an empirical closure equation obtained from observations of solar wind flow past the Earth's magnetosphere. The latter is related with the criterion of the anisotropic ion cyclotron instability. In the presented model, the total pressure, defined as the sum of magnetic pressure and perpendicular plasma pressure, is assumed to be a known function of Cartesian coordinates. The calculation is based on the Newtonian approximation for the total pressure along the obstacle and on a quadratic behavior with distance from the obstacle along the normal direction. Profiles of magnetic field strength and plasma parameters are presented along the stagnation stream line between the shock and obstacle of an ideal plasma flow with anisotropy in thermal pressure and temperature.

http://icm.krasn.ru/refextra.php?id=1472,
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Держатели документа:
ИВМ СО РАН : 660036, Красноярск, Академгородок, 50, стр.44

Доп.точки доступа:
Biernat, H.K.; Farrugia, C.J.; Еркаев, Николай Васильевич
   В3
   Z79

    The Universal Limit in Dynamics of Dilute Polymeric Solutions
[Text]. - Electronic data (164 Kb)
. - Режим доступа: http://icm.krasn.ru/refextra.php?id=1496. - Электрон. версия печ. публикации . - Режим доступа: http://library.krasn.ru/trudy/2000/1496gorban_PhAPoly00.pdf (Полный текст) : статья / V.B. Zmievskii, I.V. Karlin, M. Deville. - Electronic data (164 Kb) // Physica A. - 2000. - 275. - p. 152-177
   Перевод заглавия: Универсальный предел в динамике разбавленных растворов полимеров

Аннотация: The method of invariant manifold is developed for a derivation of reduced description in kinetic equations of dilute polymeric solutions. It is demonstrated that this reduced description becomes universal in the limit of small Deborah and Weissenberg numbers, and it is represented by the (revised) Oldroyd 8 constants constitutive equation for the polymeric stress tensor. Coe_cients of this constitutive equation are expressed in terms of the microscopic parameters. A systematic procedure of corrections to the revised Oldroyd 8 constants equations is developed. Results are tested with simple flows.

http://icm.krasn.ru/refextra.php?id=1496,
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Держатели документа:
ИВМ СО РАН : 660036, Красноярск, Академгородок, 50, стр.44

Доп.точки доступа:
Karlin, I.V.; Карлин, Илья Вениаминович; Deville, M.; Змиевский В.Б.
   В18
   Д304

    Моделирование и оптимизация технических систем с распределенными параметрами
[Текст] = Simulation and optimization of engeneering systems with distributed parametres : учебное пособие / Н. Д. Демиденко, Л. В. Кулагина. - Красноярск : КГТУ, 2006. - 210 с. : ил. - (Ресурсосбережение и экологическая безопасность = РЭБ). - Парал. загл. на англ. - Библиогр.: с. 210. - ISBN 5-7636-0411-3 : Б. ц.
УДК
ББК В18

Аннотация: Изложены основные положения теории и методов моделирования и оптимального управления для систем с распределенными параметрами. Приведены математические модели процессов тепломассопередачи в технологических установках. Сформулированы краевые задачи для анализа нестационарных режимов процессов теплообмена, разделения многокомпонентных смесей и горения. Рассмотрены задачи оптимального управления технологическими установками и методы их решения. Теоретические проблемы моделирования и оптимизации решены для некоторых конкретных объектов промышленности. Также даны контрольные вопросы и задачи, позволяющие закрепить теоретические знания и развить практические навыки решения задач по автоматизации технических систем. Предназначено для студентов специальностей "Тепловые электрические станции", "Промышленная теплоэнергетика", "Энергетика теплотехнологий" направления подготовки дипломированных специалистов "Теплоэнергетика", а также может быть полезным для студентов специальностей "Прикладная математика", "Автоматизация систем обработки информации и управление", "Системный анализ и управление"
Basic aspects of the theory and methods for simulation and optimal control for systems with distributed parameters are stated. Mathematical models of heat and mass transfer processes in processing systems are given. Boundary problems for the analysis of unsteadly conditions of heat exchange processes, segregation of multicomponent mixes and their burning are formulated. Tasks of technological installations optimal control and solution methods are considered. Theoretical issues of simulating and optimization are solved for industrial abstract entities. Control questions and test tasks which allow mastering theoretical knowledge and developing practical skills in solving tasks on technical systems automation are also presented. Intended for the students of Specialties "Heat Power Stations", "Industrial Thermal Power Engineering", "Power Engineering of Heat Technologies" of the under-graduate studies education field "Thermal Power Engineering", and also can be useful to students of specialties "Applied Mathematics", "Automation of Information Processing Systems and Controlling", "System Analysis and Controlling"


Доп.точки доступа:
Кулагина, Л.В. Др
Свободных экз. нет

    Convective instability of Marangoni-Poiseuille flow under a longitudinal temperature gradient
[Text] : статья / V.B. Bekezhanova // Journal of Applied Mechanics and Technical Physics. - 2011. - Vol. 52, Iss. 1. - p. 74-81DOI 10.1134/S0021894411010111 . -

Аннотация: An exact solution is obtained for the problem of steady flow in a system of two horizontal layers of immiscible fluids with a common interface. The stability of the flow is studied by a linearization method. It is shown that the occurrence of instabilities is due to the different governing parameters of the fluids (thickness, heating conditions, viscous and thermal conductivity of the fluids). It is found that under constant gravity conditions, the perturbations are monotonic, and in zero gravity, oscillatory thermocapillary instability occurs.

Полный текст на сайте правообладателя


Доп.точки доступа:
Бекежанова, Виктория Бахытовна

    Group properties and exact solutions of equations for vibrational convection of a binary mixture
[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

    Singularities of Transition Processes In Dynamical Systems
[Electronic resource]. - Electronic text data : статья / A. N. Gorban. - Electronic text data // Electronic Journal of Differential Equations. - 1997. - Translation of Candidat (Ph.D) Thesis

Аннотация: The paper gives a systematic analysis of singularities of transition processes in dynamical systems. General dynamical systems with dependence on parameter are studied. A system of relaxation times is constructed. Each relaxation time depends on three variables: initial conditions, parameters k of the system and accuracy ε of the relaxation. The singularities of relaxation times as functions of (x0,k) under fixed ε are studied. The classification of different bifurcations (explosions) of limit sets is performed. The relations between the singularities of relaxation times and bifurcations of limit sets are studied. The peculiarities of dynamics which entail singularities of transition processes without bifurcations are described as well. The analogue of the Smale order for general dynamical systems under perturbations is constructed. It is shown that the perturbations simplify the situation: the interrelations between the singularities of relaxation times and other peculiarities of dynamics for general dynamical system under small perturbations are the same as for the Morse-Smale systems.

Полный текст

Держатели документа:
ИВМ СО РАН : 660036, Красноярск, Академгородок, 50, стр.44

Доп.точки доступа:
Горбань, Александр Николаевич

    The radiation force rectification effect and light-induced transport phenomena in a resonant gas
[Text] : статья / I.V. Krasnov // Journal of Experimental and Theoretical Physics. - 1995. - Vol. 80, № 4. - p. 632-641 ; Zhurnal Eksperimental'noi i Teoreticheskoi Fiziki. - 1995. - Vol. 107. - p. 1135-1152

Аннотация: The possibility is demonstrated of using intense interfering light fields to form a bulk, rectified, induced-light-pressure force, thereby making it possible to efficiently act on transport phenomena of a small resonant admixture in a buffer gas. This force is capable of inducing rotating or fixed spatially periodic structures in a dense gas. The symmetry and other characteristics of such a sharp periodic stratification of the gas are extremely sensitive to the spatial configuration, phases, and parameters of the fields acting on it.

Полный текст на сайте журнала

Держатели документа:
ИВМ СО РАН : 660036, Красноярск, Академгородок, 50, стр.44

Доп.точки доступа:
Краснов, Игорь Васильевич


    Interference phenomena and radiation-force rectification
[Text] : статья / A.P. Kazantsev, I.V. Krasnov // Journal of Experimental and Theoretical Physics. - 1989. - Vol. 68, № 1. - p. 59-64 ; Zhurnal Eksperimental'noi i Teoreticheskoi Fiziki. - 1989. - Vol. 95. - p. 104-113

Аннотация: The possibility is demonstrated of using intense interfering light fields to form a bulk, rectified, induced-light-pressure force, thereby making it possible to efficiently act on transport phenomena of a small resonant admixture in a buffer gas. This force is capable of inducing rotating or fixed spatially periodic structures in a dense gas. The symmetry and other characteristics of such a sharp periodic stratification of the gas are extremely sensitive to the spatial configuration, phases, and parameters of the fields acting on it.

Полный текст на сайте журнала

Держатели документа:
ИВМ СО РАН : 660036, Красноярск, Академгородок, 50, стр.44

Доп.точки доступа:
Krasnov, I.V.; Краснов, Игорь Васильевич


    Features of the interaction of interplanetary coronal mass ejections/magnetic clouds with the Earth's magnetosphere
/ C. J. Farrugia [et al.] // J. Atmos. Sol.-Terr. Phys. - 2013. - Vol. 99. - P14-26, DOI 10.1016/j.jastp.2012.11.014. - Cited References: 53. - C.J.F. is supported by NASA Grant NNX10AQ29G and NSF Grant AGS-1140211. N.V.E. acknowledges support from Austrian Science Fund Project I193-N16 and RFBR Grant no 12-05-00152-a. N.L. acknowledges support from NSF Grant AGS-1140211. Work at LANL was conducted under the auspices of the U.S. Department of Energy with partial support from NASA and NSF. . - 13. - ISSN 1364-6826
РУБ Geochemistry & Geophysics + Meteorology & Atmospheric Sciences

Аннотация: The interaction of interplanetary coronal mass ejections (ICMEs) and magnetic clouds (MCs) with the Earth's magnetosphere exhibits various interesting features principally due to interplanetary parameters which change slowly and reach extreme values of long duration. These, in turn, allow us to explore the geomagnetic response to continued and extreme driving of the magnetosphere. In this paper we shall discuss elements of the following: (i) anomalous features of the flow in the terrestrial magnetosheath during ICME/MC passage and (ii) large geomagnetic disturbances when total or partial mergers of ICMEs/MCs pass Earth. In (i) we emphasize two roles played by the upstream Alfven Mach number in solar wind-magnetosphere interactions: (i) It gives rise to wide plasma depletion layers. (ii) It enhances the magnetosheath flow speed on draped magnetic field lines. (By plasma depletion layer we mean a magnetosheath region adjacent to the magnetopause where magnetic forces dominate over hydrodynamic forces.) In (ii) we stress that the ICME mergers elicit geoeffects over and above those of the individual members. In addition, features of the non-linear behavior of the magnetosphere manifest themselves. (C) 2012 Elsevier Ltd. All rights reserved.


Доп.точки доступа:
Farrugia, C.J.; Erkaev, N.V.; Еркаев, Николай Васильевич; Jordanova, V.K.; Lugaz, N.; Sandholt, P.E.; Muhlbachler, S.; Torbert, R.B.

    Deep Solar Activity Minimum 2007-2009: Solar Wind Properties and Major Effects on the Terrestrial Magnetosphere
/ C. J. Farrugia [et al.] // Sol. Phys. - 2012. - Vol. 281, Is. 1. - pp. 461-489, DOI 10.1007/s11207-012-0119-1. - Cited References: 53 . - 29. - ISSN 0038-0938
РУБ Astronomy & Astrophysics

Аннотация: We discuss the temporal variations and frequency distributions of solar wind and interplanetary magnetic field parameters during the solar minimum of 2007-2009 from measurements returned by the IMPACT and PLASTIC instruments on STEREO-A. We find that the density and total field strength were significantly weaker than in the previous minimum. The Alfv,n Mach number was higher than typical. This reflects the weakness of magnetohydrodynamic (MHD) forces, and has a direct effect on the solar wind-magnetosphere interactions. We then discuss two major aspects that this weak solar activity had on the magnetosphere, using data from Wind and ground-based observations: i) the dayside contribution to the cross-polar cap potential (CPCP), and ii) the shapes of the magnetopause and bow shock. For i) we find a low interplanetary electric field of 1.3 +/- 0.9 mV m(-1) and a CPCP of 37.3 +/- 20.2 kV. The auroral activity is closely correlated to the prevalent stream-stream interactions. We suggest that the Alfven wave trains in the fast streams and Kelvin-Helmholtz instability were the predominant agents mediating the transfer of solar wind momentum and energy to the magnetosphere during this three-year period. For ii) we determine 328 magnetopause and 271 bow shock crossings made by Geotail, Cluster 1, and the THEMIS B and C spacecraft during a three-month interval when the daily averages of the magnetic and kinetic energy densities attained their lowest value during the three years under survey. We use the same numerical approach as in Fairfield's (J. Geophys. Res. 76, 7600, 1971) empirical model and compare our findings with three magnetopause models. The stand-off distance of the subsolar magnetopause and bow shock were 11.8 R-E and 14.35 R-E, respectively. When comparing with Fairfield's (1971) classic result, we find that the subsolar magnetosheath is thinner by similar to 1 R-E. This is mainly due to the low dynamic pressure which results in a sunward shift of the magnetopause. The magnetopause is more flared than in Fairfield's model. By contrast the bow shock is less flared, and the latter is the result of weaker MHD forces.

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Доп.точки доступа:
Farrugia, C.J.; Harris, B.; Leitner, M.; Mostl, C.; Galvin, A.B.; Simunac, K.D.C.; Torbert, R.B.; Temmer, M.B.; Veronig, A.M.; Erkaev, N.V.; Еркаев, Николай Васильевич; Szabo, A.; Ogilvie, K.W.; Luhmann, J.G.; Osherovich, V.A.

    On validation of the SIgMA.CA pedestrian dynamics model with bottleneck flow
/ E.Kirik, T.Vitova // Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics). - 2012. - Vol. 7495 LNCS: 10th International Conference on Cellular Automata for Research and Industry, ACRI 2012 (24 September 2012 through 27 September 2012, Santorini Island. - pp. 719-727, DOI 10.1007/978-3-642-33350-7-74 . -
Аннотация: In this paper a connection of a width of a bottleneck and unidirectional virtual people flow by the SIgMA.CA pedestrian movement model (stochastic Cellular Automata model) is investigated. Specific and full flow rates for different model parameters, initial densities, and bottleneck width are presented and discussed. В© 2012 Springer-Verlag Berlin Heidelberg.

Scopus


Доп.точки доступа:
Kirik, E.; Кирик, Екатерина Сергеевна; Vitova, T.

    Numerical solving dynamic problems of elastoplastic deformation of solids
[Text] / I. O. Bogulskii, Y. M. Volchkov // Numerical Analysis and Applications. - 2012. - Vol. 5, Is. 2. - pp. 124-128, DOI 10.1134/S1995423912020048 . - ISSN 1995-4239
Аннотация: Numerical schemes for solving two-dimensional dynamic problems of elasticity theory based upon several local approximations for each of the required functions are discussed. The schemes contain free parameters (dissipation constants). An explicit form of artificial dissipation of the solutions allows us to control its size and to effectively construct both explicit and implicit schemes. The principle of producing such schemes is applied to a plane dynamic problem of elasticity theory as an example. We describe a class of problems for which numerical algorithms using several local approximations for each of the required functions are constructed. Examples of solving practical problems are given. В© 2012 Pleiades Publishing, Ltd.

Scopus,
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Доп.точки доступа:
Bogulskii, I.O.; Богульский, Игорь Олегович; Volchkov, Y.M.

    Numerical modeling of vertical stratification of Lake Shira in summer
[Text] / P.V. Belolipetsky [et al.] // Aquat. Ecol. - 2010. - Vol. 44, Is. 3. - pp. 561-570, DOI 10.1007/s10452-010-9330-z. - Cited References: 35. - The study was financially supported by the Netherlands Organization for Scientific Research (NWO), Grant 047.011.2004.030, RFBR, Grant 05-05-89002; RFBR, Grant 07-01-00153; Multidisciplinary integration project of SB RAS No. 95. . - ISSN 1386-2588
РУБ Ecology + Limnology + Marine & Freshwater Biology

Аннотация: A one-dimensional numerical model and a two-dimensional numerical model of the hydrodynamic and thermal structure of Lake Shira during summer have been developed, with several original physical and numerical features. These models are well suited to simulate the formation and dynamics of vertical stratification and provide a basis for an ecological water-quality model of the lake. They allow for the quantification of the vertical mixing processes that govern not only the thermal structure but also the nutrient exchange, and more generally, the exchange of dissolved and particulate matter between different parts of the lake. The outcome of the calculations has been compared with the field data on vertical temperature and salinity distributions in Lake Shira. Lake Shira is meromictic and exhibits very stable annual stratification. The stratification is so stable because of the high salinity of the water. If the water in Lake Shira were fresh and other parameters (depth, volume, and meteorology) were the same, as now, the lake would be mixed in autumn. Using the newly developed models and using common meteorological parameters, we conclude that Lake Shira will remain stratified in autumn as long as the average salinity is higher than 3%.


Доп.точки доступа:
Belolipetsky, P.V.; Белолипецкий, Павел Викторович; Belolipetskii, V.M.; Белолипецкий, Виктор Михайлович; Genova, S.N.; Генова, Светлана Николаевна; Mooij, W.M.

    Analysis of energy balance of the arc discharge limited by walls
[Text] / E.N. Vasiliev // Thermophys. Aeromechanics. - 2010. - Vol. 17, Is. 3. - pp. 411-418, DOI 10.1134/S0869864310030121. - Cited References: 13 . - ISSN 0869-8643
РУБ Thermodynamics + Mechanics

Кл.слова (ненормированные):
arc discharge -- heat exchange -- radiation regime -- channel model

Аннотация: The modeling of the formation of the equilibrium arc discharge structure in the axisymmetric formulation was carried out in a wide range of the values of current and radius. The boundary separating the radiation and heat-conducting regimes of discharge combustion was determined from computed data. The influence of energy mechanisms on the structure of the discharge was analysed, and a channel model was proposed for computing its parameters in the radiation regime.


Доп.точки доступа:
Vasiliev, E.N.; Васильев, Евгений Николаевич

    Dynamical modeling of microRNA action on the protein translation process
[Text] / A.Zinovyev [et al.] // BMC Syst. Biol. - 2010. - Vol. 4. - Ст. 13, DOI 10.1186/1752-0509-4-13. - Cited References: 66. - We acknowledge support from Agence Nationale de la Recherche (project ANR-08-SYSC-003 CALAMAR) and from the Projet Incitatif Collaboratif "Bioinformatics and Biostatistics of Cancer" at Institut Curie. AZ and EB are members of the team "Systems Biology of Cancer" Equipe labellis'ee par la Ligue Nationale Contre le Cancer. This work was supported by the European Commission Sixth Framework Programme Integrated Project SIROCCO contract number LSHG-CT-2006-037900. We thank Vitaly Volpert and Laurence Calzone for inspiring and useful discussions. . - ISSN 1752-0509
РУБ Mathematical & Computational Biology

Аннотация: Background: Protein translation is a multistep process which can be represented as a cascade of biochemical reactions (initiation, ribosome assembly, elongation, etc.), the rate of which can be regulated by small non-coding microRNAs through multiple mechanisms. It remains unclear what mechanisms of microRNA action are the most dominant: moreover, many experimental reports deliver controversial messages on what is the concrete mechanism actually observed in the experiment. Nissan and Parker have recently demonstrated that it might be impossible to distinguish alternative biological hypotheses using the steady state data on the rate of protein synthesis. For their analysis they used two simple kinetic models of protein translation. Results: In contrary to the study by Nissan and Parker, we show that dynamical data allow discriminating some of the mechanisms of microRNA action. We demonstrate this using the same models as developed by Nissan and Parker for the sake of comparison but the methods developed (asymptotology of biochemical networks) can be used for other models. We formulate a hypothesis that the effect of microRNA action is measurable and observable only if it affects the dominant system (generalization of the limiting step notion for complex networks) of the protein translation machinery. The dominant system can vary in different experimental conditions that can partially explain the existing controversy of some of the experimental data. Conclusions: Our analysis of the transient protein translation dynamics shows that it gives enough information to verify or reject a hypothesis about a particular molecular mechanism of microRNA action on protein translation. For multiscale systems only that action of microRNA is distinguishable which affects the parameters of dominant system (critical parameters), or changes the dominant system itself. Dominant systems generalize and further develop the old and very popular idea of limiting step. Algorithms for identifying dominant systems in multiscale kinetic models are straightforward but not trivial and depend only on the ordering of the model parameters but not on their concrete values. Asymptotic approach to kinetic models allows putting in order diverse experimental observations in complex situations when many alternative hypotheses co-exist.


Доп.точки доступа:
Zinovyev, A.; Morozova, N.; Nonne, N.; Barillot, E.; Harel-Bellan, A.; Gorban, A.N.; Горбань, Александр Николаевич

    The role of magnetic handedness in magnetic cloud propagation
[Text] / U. Taubenschuss [et al.] // Ann. Geophys. - 2010. - Vol. 28, Is. 5. - pp. 1075-1100, DOI 10.5194/angeo-28-1075-2010. - Cited References: 92. - The author appreciates financial support on behalf of the projects 06/9690 from the Austrian Research Community and A3-12T63/2007-1 from the Styrian government. Participation at the ISSS8 was made possible due to the travel fellowship of UCLA. Nikolai Erkaev acknowledges support by RFBR grants Nos. 07-05-00135 and 09-05-91000-ANF. Charles Farrugia received NASA grants NNG06GD41G and NNX08AD11G. Christian Mostl and Ute Amerstorfer work under FWF projects P20145N16 and P21051-N16 of the Austrian Science Foundation, respectively. . - ISSN 0992-7689
РУБ Astronomy & Astrophysics + Geosciences, Multidisciplinary + Meteorology & Atmospheric Sciences

Аннотация: We investigate the propagation of magnetic clouds (MCs) through the inner heliosphere using 2.5-D ideal magnetohydrodynamic (MHD) simulations. A numerical solution is obtained on a spherical grid, either in a meridional plane or in an equatorial plane, by using a Roe-type approximate Riemann solver in the frame of a finite volume approach. The structured background solar wind is simulated for a solar activity minimum phase. In the frame of MC propagation, special emphasis is placed on the role of the initial magnetic handedness of the MC's force-free magnetic field because this parameter strongly influences the efficiency of magnetic reconnection between the MC's magnetic field and the interplanetary magnetic field. Magnetic clouds with an axis oriented perpendicular to the equatorial plane develop into an elliptic shape, and the ellipse drifts into azimuthal direction. A new feature seen in our simulations is an additional tilt of the ellipse with respect to the direction of propagation as a direct consequence of magnetic reconnection. During propagation in a meridional plane, the initial circular cross section develops a concave-outward shape. Depending on the initial handedness, the cloud's magnetic field may reconnect along its backside flanks to the ambient interplanetary magnetic field (IMF), thereby losing magnetic flux to the IMF. Such a process in combination with a structured ambient solar wind has never been analyzed in detail before. Furthermore, we address the topics of force-free magnetic field conservation and the development of equatorward flows ahead of a concave-outward shaped MC. Detailed profiles are presented for the radial evolution of magnetoplasma and geometrical parameters. The principal features seen in our MHD simulations are in good agreement with in-situ measurements performed by spacecraft. The 2.5-D studies presented here may serve as a basis under more simple geometrical conditions to understand more complicated effects seen in 3-D simulations.


Доп.точки доступа:
Taubenschuss, U.; Erkaev, N.V.; Еркаев, Николай Васильевич; Biernat, H.K.; Farrugia, C.J.; Mostl, C.; Amerstorfer, U.V.

    Mathematical modeling of the electrolytic obtaining of aluminum to solve technology-control problems
[Text] / V. M. Belolipetskii, T. V. Piskazhova // Russ. J. Non-Ferrous Metals. - 2013. - Vol. 54, Is. 5. - P398-402, DOI 10.3103/S1067821213050039. - Cited References: 5 . - ISSN 1067-8212
РУБ Metallurgy & Metallurgical Engineering

Аннотация: A thermal dynamic model of the electrolyzer is considered and certain production events are modeled. Results of variations in production parameters after controlling actions are considered.

Полный текст


Доп.точки доступа:
Belolipetskii, V.M.; Белолипецкий, Виктор Михайлович; Piskazhova, T.V.