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1.
Granular materials, such as powders and sand, tend to segregate due to differences in particle properties. When a cylindrical drum is partially filled with particles of different sizes and rotated about its axis, this leads to radial segregation patterns in which the smaller particles concentrate in a radial core near the axis, and the larger particles near the outside walls of the drum. Under certain conditions, undulations in the radial core of smaller particles grow into radial stripes that extend toward the outer walls of the drum in a manner somewhat reminiscent of viscous fingering. The patterns are strongly dependent on the fill level and rotation speed of the drum. These observations can be explained by two spatially disjoint mechanisms: (1) a wave‐breaking mechanism that promotes the growth of the stripes and (2) a filtering mechanism that limits the growth of stripes. © 2005 Wiley Periodicals, Inc. Complexity 10: 79–86, 2005 相似文献
2.
The Discrete Element Method (DEM) is used to understand the formation of radial streak patterns produced when binary granular material (which may differ either in size, density or shape) segregate in a slowly rotating drum. Our simulations show that initial streak formation requires temporal fluctuations in the particle bed’s strength. This, in turn, creates fluctuations in the slope and shape of the upper surface of the bed which control the particle avalanches down the free surface. These ultimately lead to streak formation. We conjecture that growth and stabilisation of a regular streak pattern requires the two sets of particles to have significantly different angles of repose. 相似文献
3.
A series of CoxAg1-x nanostructured granular films have been prepared by ion beam sputtering and annealed at 100, 250, 400, 500℃. The optical constants, the complex dielectric function and magneto-optical Kerr parameters were measured at room temperature. For the samples having low Co compositions, the strong Kerr effect enhancement is observed around the Ag plasma edge. With an increase in annealing temperature, the resonance-like peaks appear in the Kerr rotation, and the peak positions are shifted toward the low photon energy region. From the analysis of the numerical calculations, it is concluded that the magneto-optical Kerr effect enhancement (MOKE) is due to the presence of the steep plasma edge. 相似文献
4.
G. N. Finogenov B. I. Panshin E. I. Stepanychev Yu. Ya. Voloshenko-Klimovitskii Ya. D. Avrasin 《Mechanics of Composite Materials》1970,6(5):723-727
The tensile strengths of glass laminates of various compositions under standard, high-speed and impact loading have been experimentally investigated in relation to the effect of low-temperature and stress raisers. As the loading rate increases (from 0.7 to 253 · 103 kgf/cm2. · sec) and the temperature falls to –196° C, the effective stress concentration coefficient decreases, which indicates that the glass laminates will perform adequately under these conditions.All-Union Scientific-Research Institute of Aviation Materials, Moscow. Translated from Mekhanika Polimerov, No. 5, pp. 836–841, September–October, 1970. 相似文献
5.
We consider the motion of a two-dimensional interface separating an inviscid, incompressible, irrotational fluid, influenced by gravity, from a region of zero density. We show that under certain conditions the equations of motion, linearized about a presumed time-dependent solution, are wellposed; that is, linear disturbances have a bounded rate of growth. If surface tension is neglected, the linear equations are well-posed provided the underlying exact motion satisfies a condition on the acceleration of the interface relative to gravity, similar to the criterion formulated by G. I. Taylor. If surface tension is included, the linear equations are well-posed without qualifications, whether the fluid is above or below the interface. An interesting qualitative structure is found for the linear equations. A Lagrangian approach is used, like that of numerical work such as [3], except that the interface is assumed horizontal at infinity. Certain integral equations which occur, involving double layer potentials, are shown to be solvable in the present case. © 1993 John Wiley & Sons, Inc. 相似文献
6.
The present work applies the integral method to analyze the momentum and mass transfer in thin liquid films on spinning disks, with the aim to describe the complex process of wet chemical etching of rotating silicon wafers The obtained results capture very well the essential features of the etching activity on the disk, and are in good agreement with experimental results. (© 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
7.
A series of CoxAg1 - x nanostructured granular films have been prepared by ion beam sputtering and annealed at 100, 250, 400, 500°C. The optical constants, the complex dielectric function and magneto-optical Kerr parameters were measured at room temperature. For the samples having low Co compositions, the strong Kerr effect enhancement is observed around the Ag plasma edge. With an increase in annealing temperature, the resonance-like peaks appear in the Kerr rotation, and the peak positions are shifted toward the low photon energy region. From the analysis of the numerical calculations, it is concluded that the magneto-optical Kerr effect enhancement (MOKE) is due to the presence of the steep plasma edge. 相似文献
8.
Kais Ammari Abdelkader Saïdi 《Zeitschrift für Angewandte Mathematik und Physik (ZAMP)》2006,57(5):832-846
In this paper we study the stabilization of plate vibrations by means of piezoelectric actuators. In this situation the geometric
control condition of Bardos, Lebeau and Rauch [6] is not satisfied. We prove that we have exponential stability for the low
frequencies but not for the high frequencies. We give an explicit decay rate for regular initial data at high frequencies
while clarifying the behavior of the constant which intervenes in this estimation there function of the frequency of cut n. The method used is based on some trace regularity which reduces stability to some observability inequalities for the corresponding
undamped problem. Moreover, we show numerically at low frequencies, that the optimal location of the actuator is the center
of the domain Ω.
Research supported by the RIP program of Oberwolfach Institut and by the Tunisian Ministry for Scientific Research and Technology
(MRST) under Grant 02/UR/15-01.
Research supported by the RIP program of Oberwolfach Institut.
(Received: September 17, 2003; revised: February 26, 2004) 相似文献
9.
Kais Ammari Abdelkader Sa?di 《Zeitschrift für Angewandte Mathematik und Physik (ZAMP)》2006,56(1):832-846
In this paper we study the stabilization of plate vibrations by means of piezoelectric actuators. In this situation the geometric
control condition of Bardos, Lebeau and Rauch [6] is not satisfied. We prove that we have exponential stability for the low
frequencies but not for the high frequencies. We give an explicit decay rate for regular initial data at high frequencies
while clarifying the behavior of the constant which intervenes in this estimation there function of the frequency of cut n. The method used is based on some trace regularity which reduces stability to some observability inequalities for the corresponding
undamped problem. Moreover, we show numerically at low frequencies, that the optimal location of the actuator is the center
of the domain Ω. 相似文献
10.
Edward R. D'Sa 《Zeitschrift für Angewandte Mathematik und Physik (ZAMP)》1970,21(5):768-779
Zusammenfassung Ein Rotationskörper und ein koaxialer Zylinder rotieren unabhängig und erzeugen eine stationäre MHD-Strömung in der zwischenliegenden Flüssigkeit, in einem gleichförmigen axialen magnetischen FeldB
o. Unter der Annahme, dass (die Hartmann-Zahl)M 1, dassM Re undM Rm findet man, dass die Flüssigkeit ausserhalb des Zylinders, der parallel zuB
o den Körper berührt und umhüllt, im wesentlichen mit dem äusseren Zylinder starr mitrotiert. Zonen mit Scherströmung parallel zuB
o beginnen an beiden Enden des Körpers vom Maximalkreis und gehen in einer Distanz der OrdnungM in parabolische Dellen über. In kleineren Distanzen rotiert die Flüssigkeit innerhalb der Scherschichten starr mit dem Mittelwert der Winkelgeschwindigkeit von Körper und Zylinder; zwischen dieser Flüssigkeit und dem Körper findet man eine Hartmann-Schicht. 相似文献
11.
Evans Curry Shelby Hildebrand Mark Kunkei Ann Pittman Derald Walling 《International Journal of Mathematical Education in Science & Technology》2013,44(6):997-1001
Completion and performance data from 92 high ability seventh and eighth grade students in an eight‐week summer programme conducted in 1989 and sponsored by the GTE Service Corporation are examined. 相似文献
12.
The paper analyses the effect of normal contact with friction on the generation of full band-gaps in sonic composites. The behavior of contact interfaces are computed by using LISA (local interaction simulation approach). LISA is an efficient tool for numerical simulation of the acoustic wave propagation in heterogeneous material specimens, in particular those with contact interfaces between different materials, like in sonic composites. (© 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
13.
A series of CoxAg1 - x nanostructured granular films have been prepared by ion beam sputtering and annealed at 100, 250, 400, 500°C. The optical
constants, the complex dielectric function and magneto-optical Kerr parameters were measured at room temperature. For the
samples having low Co compositions, the strong Kerr effect enhancement is observed around the Ag plasma edge. With an increase
in annealing temperature, the resonance-like peaks appear in the Kerr rotation, and the peak positions are shifted toward
the low photon energy region. From the analysis of the numerical calculations, it is concluded that the magneto-optical Kerr
effect enhancement (MOKE) is due to the presence of the steep plasma edge. 相似文献
14.
M.I. Isaev 《Applicable analysis》2013,92(11):2262-2274
We give an instability estimate for the Gel'fand inverse boundary value problem at high energies. Our instability estimate shows an optimality of several important preceding stability results on inverse problems of such a type. 相似文献
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Conclusions 1. A decrease in flow rate is observed upon increase in the pressure drop between the ends of a capillary at large pressure drops in the unstable flow region.2. It has been ascertained that the radial distribution of mean lengthwise velocity has an inflection close to the capillary wall.3. Wall slippage of the polymer has been observed and measured.4. A correlation of velocity pulsations in the channel with disturbances in the jet has been established.Institute of Problems of Mechanics, Academy of Sciences of the USSR, Moscow. Moscow Power Institute. Translated from Mekhanika Polimerov, No. 4, pp. 724–730, July–August, 1976. 相似文献
20.
In this note, the problem of a sphere carrying a fluid source at its centre and rotating with slow uniform angular velocity
about a diameter is studied. The analysis reveals that only the azimuthal component of velocity exists and is seen that the
effect of the source is to decrease it. Also, the couple on the sphere is found to decrease on account of the source. 相似文献