Algunos rasgos característicos de las canciones soviéticas sobre la Guerra Civil Española

El presente artículo analiza el fenómeno de las canciones soviéticas dedicadas a la Guerra Civil Española (1936-1939). La guerra en España despertó vivo interés en la Unión Soviética. La propaganda estatal usó diferentes tipos de arte para apoyar a la causa republicana en el conflicto. Las canciones que describían la lucha de los republicanos españoles se hicieron muy populares en la URSS. El artículo muestra la relación entre la imagen de España en la cultura rusa y el reflejo de los acontecimientos de la Guerra Civil en las canciones soviéticas. Se analiza el contexto ideológico de la creación de las obras estudiadas en la URSS. La Guerra Civil Española coincidió con el inicio del llamado “giro patriótico” en la URSS. Se nota la influencia de canciones revolucionarias en las obras musicales dedicadas a la causa republicana. Se mencionan rasgos característicos de las canciones estudiadas. En estas obras musicales se observa una mezcla de elementos españoles y rusos. El paisaje español se describe en una manera abstracta, sin relación a lugares concretos. En algunas canciones se introduce la comparación de los españoles con los rusos. Los autores soviéticos a menudo usan el lenguaje “heroico” para describir la lucha de los republicanos españoles. En el anexo al artículo se presenta la lista de 25 canciones soviéticas sobre la Guerra Civil Español

Thyristor-Bypassed Sub-Module Power-Groups for Achieving High-Efficiency, DC Fault Tolerant Multilevel VSCs

Achieving DC fault tolerance in modular multilevel converters requires the use of a significant number of Sub-Modules (SMs) which are capable of generating a negative voltage. This results in an increase in the number of semiconductor devices in the current path, increasing converter conduction losses. This paper introduces a thyristor augmented multilevel structure called a Power-Group (PG), which replaces the stacks of SMs in modular converters. Each PG is formed out of a series stack of SMs with a parallel force-commutated thyristor branch, which is used during normal operation as a low loss bypass path in order to achieve significant reduction in overall losses. The PG also offers negative voltage capability and so can be used to construct high efficiency DC fault tolerant converters. Methods of achieving the turn-on and turn-off of the thyristors by using voltages generated by the parallel stack of SMs within each PG are presented, while keeping both the required size of the commutation inductor, and the thyristor turn-off losses low. Efficiency estimates indicate that this concept could result in converter topologies with power-losses as low as 0.3% rated power, whilst retaining high quality current waveforms and achieving tolerance to both AC and DC faults

Features of the experimental evaluation of the fatigue resistance characteristics of power lugs

The features of the fatigue strength of the lugs in different zones of the cycle asymmetry coefficient are considered. It is shown that the most severe conditions of variable loading of the lugs correspond to a cycle asymmetry coefficient from 0.1 to 0.2. Formulas have been obtained to clarify the statistical assessment of the durability of symmetrical lug samples when, during their fatigue testing, destruction occurs on only one side. Recommendations are given for the selection of accelerated test modes with forced loading and for comparative tests at the same stress amplitude level

The Implementation of Spectral Element Method in a CAE System for the Solution of Elasticity Problems on Hybrid Curvilinear Meshes

Modern high-performance computing systems allow us to explore and implement new technologies and mathematical modeling algorithms into industrial software systems of engineering analysis. For a long time the finite element method (FEM) was considered as the basic approach to mathematical simulation of elasticity theory problems; it provided the problems solution within an engineering error. However, modern high-tech equipment allows us to implement design solutions with a high enough accuracy, which requires more sophisticated approaches within the mathematical simulation of elasticity problems in industrial packages of engineering analysis. One of such approaches is the spectral element method (SEM). The implementation of SEM in a CAE system for the solution of elasticity problems is considered. An important feature of the proposed variant of SEM implementation is a support of hybrid curvilinear meshes. The main advantages of SEM over the FEM are discussed. The shape functions for different classes of spectral elements are written. Some results of computations are given for model problems that have analytical solutions. The results show the better accuracy of SEM in comparison with FEM for the same meshes

Numerical Estimation of Effective Mechanical Properties for Reinforced Plexiglas in the Two-Dimensional Case

The paper describes an algorithm for numerical estimation of effective mechanical properties in two-dimensional case, considering finite strains. The algorithm is based on consecutive application of different boundary conditions to representative surface elements (RSEs) in terms of displacements, solution of elastic boundary value problem for each case, and averaging the stress field obtained. Effective properties are estimated as a quadratic dependence of the second Piola-Kirchhoff stress tensor upon the Green strain tensor. The results of numerical estimation of effective mechanical properties of plexiglas, reinforced with steel wire, are presented at finite strains. Numerical calculations were performed with the help of CAE Fidesys using the finite element method. The dependence of the effective properties of reinforced plexiglas upon the concentration of wires and the shape of wire cross section is investigated. In particular, it was found that the aspect ratio of reinforcing wire cross section has the most significant impact on effective moduli characterizing the material properties in the direction of larger side of the cross section. The obtained results allow one to estimate the influence of nonlinear effects upon the mechanical properties of the composite

Thyristor/Diode-Bypassed Sub-Module Power-Groups for Improved Efficiency in Modular Multilevel Converters

The half-bridge Modular Multilevel Converter (MMC) is a Voltage Source Converter (VSC) with high effi- ciency, controllability and modularity. The topology is weak to DC side faults unless bipolar sub-modules are used, but this results in decreased efficiency. Power-Groups (PGs), a thyristor augmented multilevel structure, have been proposed as a way to reduce the power-loss increase arising from achieving DC- fault-tolerance. This paper investigates whether the PG concept can also achieve significant efficiency improvements in VSCs that are not required to be DC fault tolerant. A Single Sub-Module Voltage (SSMV) method of controlling the turn-on/turn-off of the thyristor assembly within each PG structure is presented and the differences with the previously detailed Dual Sub-Module Voltage (DSMV) technique are described. Two thyristor-based PG structures for use in non-DC-fault-tolerant MMCs are proposed, one using SSMV and the other using DSMV. A comparison is made considering the required semiconductor device count, the impact on thyristor snubber design, and the overall power- losses achieved. A further, simplified, variant using a diode bypassed PG structure is presented which results in power- loss reductions during rectifier mode only. Results show that power-loss reductions of ∼ 20-25% can be achieved by using the proposed PG structures to augment a half-bridge MMC

The Clustered Insulated Gate Biopolar Transistor (CIGBT)- from concept to manufacturing

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NEGATIVE HYPER-RESOLUTION FOR PROVING STATEMENTS CONTAINING TRANSITIVE RELATIONS

A modified version of PHR~- resolution comprising negative hyper-resolution and paramodulation is introduced to reduce the search of statements that contain transitive relations. Let R be a symbol of transitive relation and let a nucleus contain the literal tRp, and let a factor of an electron be of the form C V nt,Rt2.Moreover let us suppose that tU = t,U, where U is a simultaneous most general unifier for the corresponding clash. Then the resolvent of this clash contains the subclause (C V pRt2)U. This rule of deduction is said to Be TPHR- rule. It is shown that TPHR"- resolution is complete. More precisely, it is shown that the empty clause a can be deduced from a set G of clauses which contains the axiom of transitivity Tr for the relation R by using PHR""- resolution iff can be deduced from the set G-{Tr}by using TPHR"- resolution. The efficiency of the use of TPHR~rule is illustrated by examples

Open-Delta SBC: a New Converter Topology with Low Number of Sub-Modules for MV applications

International audienceMedium voltage direct current (MVDC) technology has been experiencing a great boom of interest in recent years. This paper aims at giving a contribution to this field by proposing a new converter topology for MVDC applications. This topology is characterized by a low number of sub-modules (SMs) which is strongly related to the converter footprint and complexity. The new topology sizing is compared to the modular multilevel converter (MMC) for the same requirements to highlight advantages and disadvantages of the proposed solution

Open-Delta SBC: a New Converter Topology with Low Number of Sub-Modules for MV applications

International audienceMedium voltage direct current (MVDC) technology has been experiencing a great boom of interest in recent years. This paper aims at giving a contribution to this field by proposing a new converter topology for MVDC applications. This topology is characterized by a low number of sub-modules (SMs) which is strongly related to the converter footprint and complexity. The new topology sizing is compared to the modular multilevel converter (MMC) for the same requirements to highlight advantages and disadvantages of the proposed solution