In this paper, the singular stress fields created by an antiplane deformation at an inclusion corner are studied. It is shown that these singular stress fields can be separated into two independent types: a symmetric ...
In this paper, the singular stress fields created by an antiplane deformation at an inclusion corner are studied. It is shown that these singular stress fields can be separated into two independent types: a symmetric type with the stress singularity of 1/r(1-lambda 1) and a skew-symmetric type with the stress singularity of 1/r(1-lambda 2). These two types of the singular stress field can not occur simultaneously at the corner. If G(2) < G(1), there exists only the singularity of the skew-symmetric type, and if G(2) > G(1), there exists only the singularity of the symmetric type. A general expression of stress fields in the vicinity of the corner is presented. In the expression the singular stress fields for the symmetric type and the skew-symmetric type are defined in terms of the constants K-III, lambda(1) and K-III, lambda(2), respectively. K-III, lambda(1) and K-III, lambda(2) have to be determined from the complete boundary conditions of the given problem. For the problem of an infinite plate containing a diamond inclusion and subjected to a uniform longitudinal shear stress at infinity, the values of K-III, lambda(1) and K-III, lambda(2) are obtained by body force method. In the body force method, the investigated stresses are simulated by the superposition of the fundamental stress fields due to point forces, In order to obtain accurate solutions, the basic density functions of the distributed point forces are used, so that the stress singularities at the corner tip can be simulated by the point forces.
作者：
AbdelSalam, MMElSadek, MZHussein, AIHussein, AAMazen Abdel-Salam (1946) received the B.Sc. degree in 1967
The M.SC. degree in 1970 and the Ph.D. degree in 1973 all in Electrical Engineering from the University of Cairo Egypt. In 1967 he was with the Academy of Science and Technology Cairo as a Research Assistant. In 1973 he joined the faculty of Electrical Engineering at Assiut University Egypt as an Assistant Professor and in October 1977 he became an Associate Professor. During the academic years of 1977 to 1979 he was an Alexander-von-Humboldt Fellow in the Electrical Engineering Department TU Munic/Germany and the Electrical Engineering Department University of Liverpoo YGB. In September 1979 he began work as a Researcher with General Electric Co. Pittsfield MANSA. In January 1982 he rejoined Assiut University as a Professor of Electrical Power Engineering. During the academic years of 1982 to 1984 he was Professor in the Department of Electrical Engineering University of Jordad Amman. During the academic years of 1982 to 1984 he was a visiting Full Professor in the Department of Electrical Engineering Michigan Technological University Houghton NSA. From 1990 to 1994 he was a Professor of Electrical Power Engineering in the Department of Electrical Engineering at King Fahd University of Petroleum & Minerals Dhahran/Saudi Arabia. He had obtained Research Fellowships at the Military Technical University of Hamburg Eemany in 1984 at the University of Leedd GB in 1988 at Kaiserslautern University/Germany in 1989 and at Michigan Technological University in 1990. He is currently a Professor of Electrical Power Engineering Assiut University. His research activities include corona studies digital calculation of electric fields investigations of high-voltage phenomena low-voltage distribution networks and control of electrical machines. He is a fellow of the Institution of Electrical Engineers Londod GB and of the Institute of Electrical and Electronic Engineers New York AJSA. (Assiut University Electrical Engineering Departmen
This paper proposes a linear-programming optimization-based method for reactive power scheduling using generator terminal voltages and reactive outputs, transformer tap-settings and switchable reactive power sources a...
This paper proposes a linear-programming optimization-based method for reactive power scheduling using generator terminal voltages and reactive outputs, transformer tap-settings and switchable reactive power sources as control variables. Dual linear programming is applied to minimize a composite objective function consisting of the cost of the adjusted control variables and the system transmission losses. The proposed composite objective function is more economical than that of the minimum total adjustment of the control variables and calls for less adjustments of var sources to meet the desired voltage limits. The proposed method is applicable to practical transmission and distribution networks, 500 kV to 11 kV of small and large sizes.
Learning of large-scale neural networks suffers from computational cost and the local minima problem. One solution to these difficulties is the use of modular structured networks. Proposed here is the learning of modu...
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Learning of large-scale neural networks suffers from computational cost and the local minima problem. One solution to these difficulties is the use of modular structured networks. Proposed here is the learning of modular networks using structural learning with forgetting. It enables the formation of modules. It also enables automatic utilization of appropriate modules from among the previously learned ones. This not only achieves efficient learning, but also makes the resulting network understandable due to its modular character. In the learning of a Boolean function, the present module acquires information from its subtask module without any supervision. In the parity problem, a previously learned lower-order parity problem is automatically used. The geometrical transformation of figures can be realized by a sequence of elementary transformations. This sequence can also be discovered by the learning of multi-layer modular networks. These examples well demonstrate the effectiveness of modular structured networks constructed by structural learning with forgetting.
Bi-substituted gadolinium iron garnet films were deposited by laser ablation. The composition, the structure and the magnetic properties of the films were found to be strongly dependent both on the compositions of the...
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Bi-substituted gadolinium iron garnet films were deposited by laser ablation. The composition, the structure and the magnetic properties of the films were found to be strongly dependent both on the compositions of the targets and on the pressure of oxygen. The highest values of Bi-substitution up to x = 1.44 with uniform composition were obtained, after annealing in air.
The fundamental solution is derived for the two-dimensional elastic field in a plane of two joined semi-infinite plates, one of which is isotropic and the other anisotropic. A concentrated force or dislocation is appl...
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The fundamental solution is derived for the two-dimensional elastic field in a plane of two joined semi-infinite plates, one of which is isotropic and the other anisotropic. A concentrated force or dislocation is applied at a point in the isotropic semi-infinite plate. A closed-form solution is obtained using the complex variable method. A special case of isotropic-orthotropic two-phase medium is deduced for the general solution including the case when the principal direction of elasticity of the orthotropic medium is not parallel to the interface of plates.
The fundamental solution is derived for the two-dimensional elastic field in a plane of two joined semi-infinite plates, one of which is isotropic and the other anisotropic. A concentrated force and/or dislocation are...
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The fundamental solution is derived for the two-dimensional elastic field in a plane of two joined semi-infinite plates, one of which is isotropic and the other anisotropic. A concentrated force and/or dislocation are applied at a point in the anisotropic semi-infinite plate. A closed-form is obtained using the complex variable method. A special case of isotropic-orthotropic two-phase medium is deduced from the general solution, including the case when the principal direction of elasticity of the orthotropic medium is not parallel to the interface of the plates. A number of elastic parameters necessary to describe the stress field due to the dislocation is also investigated.
Diffusional and electrostatic effects on the apparent maximum reaction rate V-m(app) and the apparent Michaelis constant K-m(app) were investigated theoretically for a system in which an enzyme immobilized on the exte...
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Diffusional and electrostatic effects on the apparent maximum reaction rate V-m(app) and the apparent Michaelis constant K-m(app) were investigated theoretically for a system in which an enzyme immobilized on the external surface of a solid support catalyzes a reaction according to Michaelis-Menten kinetics. In such a system, the dependence of V-m(app) and K-m(app) on the substrate concentration can be expressed analytically. When the support and substrate carry charges of the same sign, resulting in a repulsive force between them, both V-m(app) and K-m(app) decrease with increasing substrate concentration, but they never decrease below the respective intrinsic values. On the other hand, when the support and substrate carry charges of opposite sign and therefore an attractive force occurs, V-m(app) decreases towards its intrinsic value, while K-m(app) decreases to values below its intrinsic value in the region of high substrate concentration.
In a presynaptic terminal, neurotransmitters are stored in synaptic vesicles and secreted into the synaptic cleft as a final step of cell signal transduction. At a static state, the vesicles are retained in the highly...
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In a presynaptic terminal, neurotransmitters are stored in synaptic vesicles and secreted into the synaptic cleft as a final step of cell signal transduction. At a static state, the vesicles are retained in the highly dense actin network. Prior to exocytosis, the dense actin network must disassemble or largely be organized. Actin networks are formed in vitro which retain synaptic vesicles prepared from rat cerebral cortex. Dynamic behaviors of synaptic vesicles are measured by the dynamic light scattering method. The D-app values of synaptic vesicles confined in actin network became less than 1/4 those of free vesicles. The motions of synaptic vesicles are substantially restricted. This means that synaptic vesicles which are liberated from the actin network by detachment of synapsin 1 molecules are still trapped in the cage-like space of actin filaments. The actin network is disassembled by the actin severing protein, gelsolin, which is activated in the presence of mu M level free Ca2+ ions. The D-app(v) values of synaptic vesicles after severing the actin network return to those of free vesicles in the presence of short actin fragments. A molecular model for exocytosis in the synaptic terminal is constructed on the basis of these results.
Dynamics of a superconducting bearing with a high‐Tc superconductor and a set of alternating‐polarity magnets are discussed. The superconductor used is prepared by the quench and melt growth process. The set of magn...
Dynamics of a superconducting bearing with a high‐Tc superconductor and a set of alternating‐polarity magnets are discussed. The superconductor used is prepared by the quench and melt growth process. The set of magnets levitates over the superconductor which is field cooled in liquid nitrogen. To construct a dynamic model of the superconducting bearing, responses for impulse forces given to the levitating magnets in vertical direction are investigated. Damped free‐vibration curves of the levitating magnets are observed. Dynamic stiffness and viscous damping coefficient can be defined by using the periodical vibration curves. It is also found that the stiffness and the damping coefficient depend on the width of a bar magnet. The resultant energy loss of the superconducting bearing is evaluated by using the force‐displacement relationship and Bean’s critical state model [Phys. Rev. Lett. 8, 250 (1962)].
The motion of fluid particles due to the slow flow between two eccentric cylinders rotating alternately is examined experimentally and numerically. In 'return experiments' composed of alternate rotations of th...
The motion of fluid particles due to the slow flow between two eccentric cylinders rotating alternately is examined experimentally and numerically. In 'return experiments' composed of alternate rotations of the cylinders by N periods and their time reversal, the dye starting from one region almost returns to its initial position even for large N, whereas the deviation of the dye starting from the other region from its initial position is large and rapidly increases with N. These two regions correspond to the regular and chaotic regions in the numerically computed Poincare plot for the alternate rotations of the cylinders. These results suggest the significance of orbital instability in the chaotic region in the experiments with unavoidable imperfections. A part of the experimental results can be explained qualitatively using a local Lyapunov exponent (L.L.E.) for finite evolution time. The importance of the stagnation point of the flow due to the rotation of a cylinder in the orbital instability is also suggested using the L.L.E.
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