1,069 research outputs found
Problems of hydrodynamics and continuum mechanics : contributions in honor of the sixtieth birthday of Academician L. I. Sedov, 14th November 1967 /
No full text"Published works of L. I. Sedov": p. 6-15.Includes bibliographies
Higher-gradient continua: The legacy of Piola, Mindlin, Sedov and Toupin and some future research perspectives
No full textSince the first studies dedicated to the mechanics of deformable bodies (by Euler, D'Alembert, Lagrange) the principle of virtual work (or virtual velocities) has been used to provide firm guidance to the formulation of novel theories. Gabrio Piola dedicated his scientific life to formulating a continuum theory in order to encompass a large class of deformation phenomena and was the first author to consider continua with non-local internal interactions and, as a particular case, higher-gradient continua. More recent followers of Piola (Mindlin, Sedov and then Richard Toupin) recognized the principle of virtual work (and its particular case, the principle of least action) as the (only!) firm foundation of continuum mechanics. Mindlin and Toupin managed to formulate a conceptual frame for continuum mechanics which is able to effectively model the complex behaviour of so-called architectured, advanced, multiscale or microstructured (meta)materials. Other postulation schemes, in contrast, do not seem able to be equally efficient. The present work aims to provide a historical and theoretical overview of the subject. Some research perspectives concerning this theoretical approach are outlined in the final section
Irreversible Aspects of Continuum Mechanics and Transfer of Physical Characteristics in Moving Fluids : Symposia
No full textAt its meeting on April 23, 1965 in Paris the Bureau of IUTAM decided to have a Symposium on the Irreversible Aspects of Continaum Mechanics held in June 1966 in Vienna. In addition, a Symposium on the Transfer of Physical Characteristics in Moving Fluids which, orig inally, had been scheduled to take place in Stockholm was rescheduled to be held in Vienna immediately following the Symposium on the Irre versible Aspects of Continuum Mechanics. It was felt that the subjects of the two symposia were so closely related that participants should be given an opportunity to attend both. Both decisions were unanimously approved by the members of the General Assembly of IUTAM. Prof. H. PARKUS, Vienna, was appointed Chairman of the Symposium on the Irreversible Aspects, and Prof. L. I. SEDOV, Moscow, was appointed Chairman of the Symposium on the Transfer of Physical Characteristics, with Prof. P ARKUS being re sponsible for the local organization of both symposia. In accordance with the policy set forth by IUTAM, membership of the Symposia was limited and by invitation only. Financial support for covering the costs of organization and for a partial defrayal of the accomodation and traveling expenses of the participants was provided by IUTAM and by the Austrian Ministry of Education
Problems of hydrodynamics and continuum mechanics contributions in honor of the sixtieth birthday of Academician L. I. Sedov, 14th Nov. 1967 ; English edition.
No full textWall Effects in Cavity Flows and their Correction Rules
Get PDFThe wall effects in cavity flows have been long recognized to be more important and more difficult to determine than those in single-phase, nonseparated flows. Earlier theoretical investigations of this problem have been limited largely to simple body forms in plane flows, based on some commonly used cavity-flow models, such as the Riabouchinsky, the reentrant jet, or the linearized flow model, to represent a finite cavity. Although not meant to be exhaustive, references may be made to Cisotti (1922), Birkhoff, Plesset and Simmons (1950, 1952), Gurevich (1953), Cohen et al. (1957, 1958), and Fabula (1964). The wall effects in axisymmetric flows with a finite cavity has been evaluated numerically by Brennen (1969) for a disk and a sphere. Some intricate features of the wall effects have been noted in experimental studies by Morgan (1966) and Dobay (1967). Also, an empirical method for correcting the wall effect has been proposed by Meijer (1967).
The presence of lateral flow boundaries in a closed water tunnel introduces the following physical effects: (i) First, in dealing with the part of irrotational flow outside the viscous region, these flow boundaries will impose a condition on the flow direction at the rigid tunnel walls. This "streamline-blocking" effect will produce extraneous forces and modifications of cavity shape. (ii) The boundary layer built up at the tunnel walls may effectively reduce the tunnel cross-sectional area, and generate a longitudinal pressure gradient in the working section, giving rise to an additional drag force known as the "horizontal buoyancy." (iii) The lateral constraint of tunnel walls results in a higher velocity outside the boundary layer, and hence a greater skin friction at the wetted body surface. (iv) The lateral constraint also affects the spreading of the viscous wake behind the cavity, an effect known as the "wake-blocking." (v) It may modify the location of the "smooth detachment" of cavity boundary from a continuously curved body.
In the present paper, the aforementioned effect (i) will be investigated for the pure-drag flows so that this primary effect can be clarified first. Two cavity flow models, namely, the Riabouchinsky and the open-wake (the latter has been attributed, independently, to Joukowsky, Roshko, and Eppler) models, are adopted for detailed examination. The asymptotic representations of these theoretical solutions, with the wall effect treated as a small correction to the unbounded-flow limit, have yielded two different wall-correction rules, both of which can be applied very effectively in practice. It is of interest to note that the most critical range for comparison of these results lies in the case when the cavitating body is slender, rather than blunt ones, and when the cavity is short, instead of very long ones in the nearly choked-flow state. Only in this critical range do these flow models deviate significantly from each other, thereby permitting a refined differentiation and a critical examination of the accuracy of these flow models in representing physical flows. A series of experiments carefully planned for this purpose has provided conclusive evidences, which seem to be beyond possible experimental uncertainties, that the Riabouchinsky model gives a very satisfactory agreement with the experimental results, and is superior to other models, even in the most critical range when the wall effects are especially significant and the differences between these theoretical flow models become noticeably large.
These outstanding features are effectively demonstrated by the relatively simple case of a symmetric wedge held in a non-lifting flow within a closed tunnel, which we discuss in the sequel
Superlinear increase of photocurrent due to stimulated scattering into a polariton condensate
No full textWe show that when a monopolar current is passed through an n-i-n structure, superlinear photocurrent response occurs when there is a polariton condensate. This is in sharp contrast to the previously observed behavior for a standard semiconductor laser. Theoretical modeling shows that this is due to a stimulated exciton-exciton scattering process in which one exciton relaxes into the condensate, while another one dissociates into an electron-hole pair.</p
k Istorii Boiarskoi Sem´i XVII v.
Get PDFAu xviie siècle, les princes Odoevskij appartenaient à la crème de l’élite moscovite. Tirant parti de documents inédits, l’auteur reconstruit l’histoire de quatre générations de cette famille, à commencer par le prince Nikita Ivanovič Odoevskij, l’un des plus célèbres bojare de l’époque d’avant Pierre le Grand. L’auteur montre comment chacune des générations successives s’efforçait de maintenir la tradition familiale, reproduisant autant que possible la carrière de ses pères. C’est ainsi que les princes Odoevskij s’affirmèrent durablement dans les premiers rangs de la Duma et dans le cercle intime du tsar. En ce sens, le règne de Pierre le Grand marque une rupture : le modèle comportemental dans lequel l’autorité des aïeux dictait les objectifs des descendants n’y a pas survécu. Durant la première moitié du xviiie siècle, les princes Odoevskij édifièrent leurs carrières en suivant leurs goûts et préférences personnels pour finalement ne laisser d’eux que l’image de gens « médiocres », « serviles » et « tricheurs aux cartes ».In the seventeenth century, the Odoevskii princes belonged to the upper crust of the Muscovite elite. On the basis of unpublished documents, the article reconstructs the history of four generations of the family starting with Nikita Ivanovich Odoevskii, one of the most notorious boyars of the pre‑Petrine era. The author shows how each generation strove to maintain family traditions by reproducing, as much as possible, their father’s and grand‑father’s careers. They thus secured their position in the top Duma ranks and the tsar’s close circle. In that respect, Peter’s reign marked a breaking point in a behavioral pattern in which younger generations were inspired by their forebears. During the first half of the eighteenth century, the Odoevskii princes built their careers following their personal tastes and preferences and were remembered as “mediocre” people, notorious for “fawning” and “cheating at cards.
Technical Physics Letters V. 30, I. 09
No full textTechnical Physics Letters -- September 2004
Volume 30, Issue 9, pp. 709-798
A New Method of Determining the Reversible Magnetization Loop of Bulk High-Temperature Superconductors
Yu. S. Ermolaev and I. A. Rudnev
pp. 709-711 Full Text: PDF (40 kB)
Modeling the Behavior of Complex Media by Jointly Using Discrete and Continuum Approaches
S. G. Psakhie, A. Yu. Smolin, Yu. P. Stefanov, P. V. Makarov, and M. A. Chertov
pp. 712-714 Full Text: PDF (156 kB)
The Synthesis and Photoelectric Properties of Si–(Si2)1 – x(ZnS)x Epitaxial Structures
B. Sapaev and A. S. Saidov
pp. 715-716 Full Text: PDF (85 kB)
Ionization Parameters of Some Nitro Compounds on the Surface of Alkali Metal Oxide Bronze
V. I. Kapustin, V. S. Petrov, and A. A. Chernousov
pp. 717-718 Full Text: PDF (29 kB)
Generation of Subnanosecond 10-GHz Pulses in High Peak and High Average Power Mode
S. D. Korovin, S. K. Lyubutin, G. A. Mesyats, V. V. Rostov, S. N. Rukin, B. G. Slovikovsky, M. R. Ul'maskulov, K. A. Sharypov, V. G. Shpak, S. A. Shunailov, and M. I. Yalandin
pp. 719-723 Full Text: PDF (124 kB)
Ionization Kinetics in a Supersonic Xenon Plasma Flow Entering Electric Field
T. A. Lapushkina, R. V. Vasil'eva, A. V. Erofeev, S. A. Ponyaev, and S. V. Bobashev
pp. 724-726 Full Text: PDF (54 kB)
Gas Adsorption on Semiconducting Oxides: A Change in the Work Function
S. Yu. Davydov, V. A. Moshnikov, and A. A. Fedotov
pp. 727-729 Full Text: PDF (42 kB)
The Effect of Neutron Irradiation on the Microhardness of Gallium Arsenide
Z. V. Jibuti, N. D. Dolidze, N. Sikhuashvili, and G. L. Eristavi
pp. 730-731 Full Text: PDF (30 kB)
Electron Chemoemission from Metal to Semiconductor
V. F. Kharlamov, S. N. Romashin, and A. V. Sedov
pp. 732-734 Full Text: PDF (46 kB)
Synergetic Description of Temperature Evolution in Strongly Inhomogeneous Media
S. O. Gladkov
pp. 735-737 Full Text: PDF (35 kB)
Photoelectron Spectroscopy of Thin-Film Yb–Si(100) Structures Formed by Solid Phase Epitaxy at 800 K
D. V. Vyalikh, M. V. Kuzmin, M. A. Mittsev, and S. L. Molodtsov
pp. 738-740 Full Text: PDF (48 kB)
Reconstructing an Object Image Using the Laser Speckle Pattern of the Diffraction Field
B. B. Gorbatenko, V. P. Ryabukho, and L. A. Maksimova
pp. 741-743 Full Text: PDF (179 kB)
Phase Inhomogeneity of Pyroboroncarbon Structure
V. N. Kukin, N. I. Borgardt, A. V. Agafonov, and V. O. Kuznetsov
pp. 744-746 Full Text: PDF (324 kB)
Orientation of Methyl Red Dye Molecules in a Polymer Matrix
A. V. Tomov and A. V. Khomchenko
pp. 747-749 Full Text: PDF (38 kB)
Optical Rectification Effect in Nanocarbon Films
G. M. Mikheev, R. G. Zonov, A. N. Obraztsov, and Yu. P. Svirko
pp. 750-752 Full Text: PDF (48 kB)
Electron Emission from Solid Surfaces Stimulated by Electric Field and Heterogeneous Chemical Reaction
V. F. Kharlamov, A. V. Sedov, and S. N. Romashin
pp. 753-755 Full Text: PDF (49 kB)
Europium Diffusion in Single Crystal Samarium Sulfide
V. A. Didik, E. A. Skoryatina, V. P. Usacheva, A. V. Golubkov, and V. V. Kaminskii
pp. 756-758 Full Text: PDF (41 kB)
Textured Tin Dioxide Films for Gas Recognition Microsystems
V. V. Sysoev, N. I. Kucherenko, and V. V. Kissin
pp. 759-761 Full Text: PDF (162 kB)
Photosensitivity of Surface Barrier Structures Based on Cu(In,Ga)Se2 Films Grown by Codeposition in Vacuum
V. Yu. Rud', Yu. V. Rud', V. F. Gremenok, and G. A. Il'chuk
pp. 762-764 Full Text: PDF (202 kB)
Peculiarities of the MBE Growth of Nanowhiskers on GaAs(100) Substrates
I. P. Soshnikov, A. A. Tonkikh, G. E. Cirlin, Yu. B. Samsonenko, and V. M. Ustinov
pp. 765-768 Full Text: PDF (175 kB)
Magnetoelectric Response of a Multilayer Ferrite–Piezoelectric Structure to Magnetic Field Pulses
A. Y. Ostashchenko, K. E. Kamentsev, Y. K. Fetisov, and G. Srinivasan
pp. 769-771 Full Text: PDF (44 kB)
Effect of the Initiating Pulse Energy on the Kinetics of Preexplosion Processes in Silver Azide
É. D. Aluker, A. G. Krechetov, A. Yu. Mitrofanov, and A. S. Pashpekin
pp. 772-773 Full Text: PDF (27 kB)
Peculiarities of the Kinetics of Explosive Decomposition of Silver Azide Initiated by a Pulsed Electron Beam
B. P. Aduev, G. M. Belokurov, S. S. Grechin, and E. V. Tupitsin
pp. 774-775 Full Text: PDF (36 kB)
Obtaining a Dispersed Liquid–Gas Mixture Using a Piston Machine: Method and Possible Applications
Yu. V. Alekhanov, A. E. Levushov, A. A. Logvinov, S. A. Lomtev, and E. E. Meshkov
pp. 776-778 Full Text: PDF (86 kB)
Synchronization of Spectral Components of Coupled Chaotic Oscillators
A. A. Koronovskii, O. I. Moskalenko, and A. E. Hramov
pp. 779-783 Full Text: PDF (174 kB)
High-Intensity X-ray Microbeams Obtained Using a Cylindrical Polycapillary Structure
A. Yu. Romanov and I. V. Dmitriev
pp. 784-785 Full Text: PDF (39 kB)
Interplay of Surface Effects in a Thin Nematic Liquid Crystal Layer
S. L. Lopatnikov and G. Gillespie, Jr.
pp. 786-790 Full Text: PDF (162 kB)
A Modified Kolmogorov Model and the Growth Rate of a Crystal Face of Arbitrary Size
N. V. Sibirev and V. G. Dubrovskii
pp. 791-794 Full Text: PDF (52 kB)
Electron Transport Effects in the IR Photoconductivity of InGaAs/GaAs Structures with Quantum Dots
V. M. Danil'tsev, M. N. Drozdov, L. D. Moldavskaya, V. I. Shashkin, A. V. Germanenko, G. M. Min'kov, and A. A. Sherstobitov
pp. 795-798 Full Text: PDF (53 kB)Archived web conten
FIG. 8. — A-D, G, J in Conodonts in the Silurian of Severnaya Zemlya and Sedov archipelagos (Russia), with special reference to the genus Ozarkodina Branson & Mehl, 1933
No full textFIG. 8. — A-D, G, J, Ozarkodina guiyangensis Zhou, Zhai & Xian, 1981; A, B, G, Cn 5981, lateral and lower views of Pa element (A in translucent light); C, D, Cn 5983, lateral and lower views of Pa element; J, Cn 5980, lateral view of Pa element in translucent light; all elements from the lower part of the Golomyannyj Formation, October Revolution Island: A, B, G, J, from Strojnaya River, section 52, sample MF 52-23; C, D from Ushakov River, section 32, sample MF 46-14; E, F, Ozarkodina aldridgei Uyeno & Barnes, 1983, specimen Cn 5960, lateral and lower views of Pa element; from the lower part of the Vodopad Formation, October Revolution Island, Strojnaya River, section 51, sample MF 51-9; H, I, K, M-P, R-T, Ozarkodina sp. A.; H, N, Cn 5971, lateral and lower views of Pa element; I, K, Cn 5973, lateral and lower views of Pa element; M, O, Cn 5972, lateral and lower views of Pa element; P, Cn 5974, lateral view of Pb element; R, Cn 5975, lateral view of M element; S, Cn 5977, posterior view of Sa element, T, Cn 5976, posterior view of Sb element; all specimens from the lowermost part of the Vodopad Formation, October revolution Island, Strojnaya River, section 51, sample MF 51-3; L, Q Ozarkodina confluens bucerus (Viira, 1983); L, Cn 6091, lateral view of Pa element; Q, Cn 6089, lateral view of Pa element; both specimens from the upper part of the Samojlovich Formation, October Revolution Island: L, from Matusevich River, section 2, sample 5-2-68k; Q, from the Spokojnaya River region, section 157, sample MF 157-6. Scale bar: 0.5 mm.Published as part of Männik, Peep, 2002, Conodonts in the Silurian of Severnaya Zemlya and Sedov archipelagos (Russia), with special reference to the genus Ozarkodina Branson & Mehl, 1933, pp. 77-97 in Geodiversitas 24 (1) on page 88, DOI: 10.5281/zenodo.537514
The generalized potentials, Riemann invariants and simple waves in analog of the Chaplygin-Sedov hodograph method in magnetic gas dynamics.
Get PDFВ случае, когда уравнения состояния и интегралы симметрии включают зависимость не только от удельного объема, но и от функций тока, в аналоге метода годографа Чаплыгина-Седова в магнитной газовой динамике введены обобщенные потенциалы, удовлетворяющие линейным уравнениям, через которые в конечном виде выражены координаты x1 и x2 и функция тока y. В случае гиперболичности основного линейного уравнения теории получены инварианты Римана и уравнения для них. В случае, когда векторы скорости и магнитного поля коллинеарны, получены решения типа простых волн, в которых скорость, напряженность магнитного поля и давление являются функциями только удельного объема. На основе способа, аналогичного способу Л. И. Седова получения класса точных решений с однородными относительными деформациями уравнений однопараметрической нестационарной газовой динамики, рассмотрен весьма общий случай интегрируемости в квадратурах уравнения для переменной "П" в плоскости годографа, аналогичной давлению в классической газовой динамике. Отдельно рассмотрен случай, когда вектор напряженности магнитного поля параллелен выделенной оси.У випадку, коли рiвняння стану та iнтеграли симетрiї мiстять залежнiсть не тiльки вiд питомого об'єму, але й вiд функцiї току, в аналозi методу Чаплигiна-Сєдова, в магнiтнiй газовiй динамiцi введенi узагальненi потенцiали, що задовольняють лiнiйним рiвнянням, через якi в кiнцевому виглядi вираженi координати x1 i x2 i функцiя току y. У випадку гiперболiчностi основного лiнiйного рiвняння теорiї одержано iнварiанти Рiмана i рiвняння для них. У випадку, коли вектори швидкостi та магнiтного поля колiнеарнi, одержано розв'язок типу простих хвиль, в яких швидкiсть, напруженiсть магнiтного поля та тиск є функцiями тiльки питомого об'єму. На основi способа, який аналогiчний способу Л. I. Сєдова одержання класа точних розв'язкiв з однорiдними вiдносними деформацiями рiвнянь однопараметричної нестацiонарної газової динамiки, розглянутий досить загальний випадок iнтегрованостi в квадратурах рiвняння для змiнної "П" в площинi годографа, аналогiчної тиску в класичнiй газовiй динамiцi. Окремо розглянуто випадок, коли вектор напруженостi магнiтного поля є паралельним вiсi, що видiлена.In case when the equations of state and the integrals of symmetry involve not only specific volume dependence, but a stream function dependence, too, generalized potentials, that fulfill the linear equations, in which the coordinates x1 and x2 and a stream function y are expressed, are introduced to analog of Chaplygin-Sedov method of hodograph in magnetic gas dynamics. In case when basic linear equation of theory is hyperbolic the Riman invariants and equations for them are obtained. In case, when vectors of the magnetic field and velocity are collinear, the solutions of simple waves type, where velocity, magnetic field intensity and pressure are the functions of only specific volume, are obtained. On basis of the method, that is analogous to L. I. Sedov method of obtaining of the class of exact solutions with homogeneous relative deformations of single--parametric nonstationary gas dynamics, the very general occasion of integrability in quadratures of the equation for the variable "П" in hodograph plane, that is analogous to pressure in classical gas dynamics, is consideredi. Тhe case is considered, when the magnetic field vector is parallel to the particular axis
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