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Magnetic pulse welding involves the joining of two metallic parts in a solid state by the use of a short and intense electromagnetic impulses and the resulting impact between the parts. The coalesced interface undergoes visco-plastic deformation at a high strain rate and exhibits a wavy shape at a microscopic scale. A practical estimation of the electromagnetic pressure, impact velocity and welded joint length as a function of the process conditions and the electromagnetic coil geometry is required but currently not available. Three novel analytical relations for the estimation of the electromagnetic pressure, impact velocity, and welded joint length for magnetic pulse welding of tubes and sheets, are presented. These relations were developed systematically, following a dimensional analysis, and validated for a wide range of conditions from independent literature. The comparison of the analytically computed results and the corresponding values reported in the literature has illustrated that the proposed analytical relations can be used for the estimation of the electromagnetic pressure and impact velocity for the magnetic pulse welding of tubes and sheets with a good level of confidence. The analytically calculated results for the welded joint length show a little discrepancy with the corresponding experimentally measured values. Further investigations and more experimentally measured results are required to arrive at a more comprehensive analytical relation for the prediction of welded joint length.

There considered a system consisting of a fast neutron batch pulsed IBR type reactor and a subcritical unit (neutronically thermal). The reactor is fitted with a reactivity modulator, which provides short-term “transfer” of the system from a deep subcritical to a prompt supercritical state and back. The system is in a deep subcritical state in the intervals between pulses. Such a system is capable to operate in an equilibrium (static) mode only when a critical condition is fulfilled for the kinetic parameters describing its operation. The neutron kinetics is described as part of a two-point approximation. It is assumed that the change in the reactor reactivity at the pulse generation time takes place periodically according to a parabolic law and the reactor is deeply subcritical in the intervals between pulses. Numerical simulation of the critical condition is extremely time-consuming, and analytical representation is almost impossible due to the need for solving ordinary differential equations with variable coefficients. There proposed a methodology for approximate estimating of parameters of a coupled “batch pulsed reactor–subcritical unit” system operating in an equilibrium mode. Analytical relations have been obtained in a quadrature form to calculate the “critical” condition of such a system in the approximation of “frequently recurring” pulses, when the decay of the delayed neutron precursors in the interval between pulses can be ignored. Calculations of the “critical condition” are illustrated by an example of a laser system consisting of an IBR-type batch pulsed reactor and a subcritical neutron multiplication unit, in which fission energy is converted into laser emission energy. Critical parameters of the system were estimated using analytical relations, as well as direct numerical calculations based on the STIK program that models the neutron kinetics in the considered system in a two-point approximation. It has been shown that the results of direct calculations and the estimates based on analytical relations matched good.

This study was designed to find an analytical formula for predicting the ultimate shear strength of a novel kind of complex steel-concrete shear walls known as double steel plate complex shear wall (DSCSW). The performance of these compound walls is now under research and no adequate design provisions are available. Three types of analytical formulae consisting of full shear yield, local and global shear elastic buckling were proposed and their precisions were investigated. To this end, a comprehensive 3D nonlinear finite element (FE) parametric analysis was performed. To carry out such parametric study, 120 FE models of DSCSWs were simulated and analyzed using ABAQUS package. All models were constructed according to an FE model of a test sample of DSCSW which had been constructed and tested in 2013 by Rafiei. The validity of that FE model was verified by comparing the simulation results with the experimental results. The variables considered in the parametric study were the profiled steel plate thickness, the compressive strength of infill concrete, the yield strength of the profiled steel plate and finally the number of the intermediate fasteners. At the end of this study, it was revealed that the full shear yield formula can provide a good estimation of the shear capacity of this type of shear walls when at least one row of the intermediate fasteners in the mid-height of the wall used for connecting the steel plates to the concrete panel. [ABSTRACT FROM AUTHOR]

It is considered the quasi-stationary approximation of a dynamic model, representing a positive feedback mechanism in the MEK/ERK signaling pathway mediated by RKIP. An analytical solution of the eight dimensional quasi-stationary system is found. Analytical relations between stationary and initial values of all signal pathway components are derived too. On the basis of them it is established that the quasi-stationary behaviour of a MEK/ERK pathway is dependent only on reactions of association and dissociation of the double phosphorylated protein ERKpp and the protein complex RKIP/Raf-1 to the three-component complex ERKpp/RKIP/Raf-1 and vice versa. Moreover, the leading role of initial concentrations of the RKIP protein complexes is determined.

In this paper, analytical and semi-analytical expressions for the effective properties of transversely isotropic piezoelectric materials are derived based on the Mori–Tanaka model and Eshelby tensors using compact matrix formulations. Concise explicit relations are presented for the coupled and decoupled effective electroelastic moduli of piezoelectric materials with various inclusion types and shapes. In order to use these explicit relationships, some of the Eshelby tensor components are needed to be analytically or numerically computed. These closed-form relations are suitable for use in designing composite piezoelectric materials with optimized characteristics. Results of effective electroelastic moduli, obtained using the derived closed-form expressions, are presented for various types and shapes of piezoelectric inclusions and compared with self-consistent and incremental self-consistent numerical predictions. [ABSTRACT FROM AUTHOR]

Simple analytical relations that can readily be applied to verify a critical aspect of numerical predictions of fully nonlinear free-surface flows around ship hulls steadily advancing in calm water are given. The relations do not involve the flow field equations; that is, they are only based on the boundary conditions at the ship hull surface and at the free surface. These boundary conditions have a predominant influence on free-surface flows around advancing ship hulls. The analytical relations are exact for inviscid flows, and can be applied to numerical methods that solve either the Laplace equation (potential-flow methods) or the Euler flow equations (CFD Euler-flow methods). They provide a simple test to verify if numerical predictions given by nonlinear potential-flow or Euler-flow methods correctly satisfy the hull-surface and free-surface boundary conditions along the contact curve between the hull surface and the free surface. The relations might also be used to verify CFD methods that solve the RANS equations if they are applied at the edge of the viscous boundary layer. The analytical test can identify an inconsistency, which might point to a "method issue" related to a feature of a numerical method (e.g., a numerical-differentiation scheme) or an "implementation issue" in the implementation of the method (e.g., a poor discretization). For purposes of illustration, the test is applied to predictions of flows around the Wigley parabolic hull given by two CFD methods that solve the Euler equations with fully nonlinear boundary conditions at the free surface. This illustrative example demonstrates that the test can indeed be useful to identify numerical inaccuracies. The analytical relations can also be used to determine experimental values of the flow velocity at a ship wave profile that correspond to measurements of the wave profile. [ABSTRACT FROM AUTHOR]

A mathematical model for mechanosynthesis in solid-gas systems is constructed which includes the equations of mechanical-reactor heat balance, grinding, the excess-energy dynamics in the condensed substances, which determines the effect of mechanical activation on the chemical-reaction rate, and the reaction kinetics. A brief analysis of the model is presented. A description is given of two simplified models of independent significance derived from the general model, which can be studied by analytical methods. Synthesis in a preactivated system is studied in detail. Relations determining the characteristics of the synthesis are obtained. The accuracy of the analytical estimates is verified by numerical simulation. [ABSTRACT FROM AUTHOR]

Magnetic pulse welding involves the joining of two metallic parts in a solid state by the use of a short and intense electromagnetic impulses and the resulting impact between the parts. The coalesced interface undergoes visco-plastic deformation at a high strain rate and exhibits a wavy shape at a microscopic scale. A practical estimation of the electromagnetic pressure, impact velocity and welded joint length as a function of the process conditions and the electromagnetic coil geometry is required but currently not available. Three novel analytical relations for the estimation of the electromagnetic pressure, impact velocity, and welded joint length for magnetic pulse welding of tubes and sheets, are presented. These relations were developed systematically, following a dimensional analysis, and validated for a wide range of conditions from independent literature. The comparison of the analytically computed results and the corresponding values reported in the literature has illustrated that the proposed analytical relations can be used for the estimation of the electromagnetic pressure and impact velocity for the magnetic pulse welding of tubes and sheets with a good level of confidence. The analytically calculated results for the welded joint length show a little discrepancy with the corresponding experimentally measured values. Further investigations and more experimentally measured results are required to arrive at a more comprehensive analytical relation for the prediction of welded joint length. [ABSTRACT FROM AUTHOR]

Summary: Following the adequate seismic behavior, the steel plate shear walls have gained popularity among the designers worldwide, and many buildings have been designed employing such walls as their lateral load‐carrying system. Despite the fact that the steel shear walls using unstiffened thin plates outnumber the ones benefitting from stiffeners, it should be kept in mind that application of stiffeners prevents the buckling induced by lateral loads such earthquake or wind. On the other hand, the stiffeners enhance the stiffness and shear strength of the plate. Accordingly, this paper deals with an analytical and numerical investigation into the steel plates stiffened by unequaled vertical and horizontal stiffeners. The results obtained for the analyses led to the development of the analytical relations to compute the shear strength, stiffness, and displacement. To validate the proposed relations, analytical outputs were compared with those obtained from the numerical investigation indicating great accuracy of the proposed analytical relations. Moreover, in this paper, the design process of the stiffened steel plate shear walls has been presented based on the interaction between the plate and frame. The results indicate the addition of stiffeners to the steel plate, improves its shear strength by 6 to 15%. [ABSTRACT FROM AUTHOR]

Larger optical penalties than predicted by a Gaussian crosstalk model are found both in our experiments and in the literature when investigating signals including multiple interferometric crosstalk contributions. We attribute this to an imperfect signal extinction ratio. In this letter, simple analytical relations for crosstalk induced power penalties are derived taking the signal extinction ratio into account and excellent agreement with 10-Gb/s experiments is obtained. Both theory and experiments show the importance of the signal extinction ratio in connection with interferometric crosstalk [ABSTRACT FROM PUBLISHER]