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In this paper, based on the three-dimensional moment theory of elasticity, a mathematical model of moment shells with the deformation concept "shear plus rotation" is constructed, equilibrium equations, geometric and physical relations of elasticity are obtained and boundary conditions are established. Based on the completeness of the constructed applied theory, the equations of continuity of deformations of the middle surface of the shell are established as necessary and sufficient conditions for the integrability of the system of the differential equations, when the values of the components of the deformation and bending-torsion tensors are given and it is required to determine the components of the vectors of displacement and free rotation. [ABSTRACT FROM AUTHOR]

In present paper the applied (one-dimensional) model of micropolar elastic thin beam with a circular axis is constructed including the variation principles, on the basis of the two-dimensional equations of micropolar theory of elasticity with constrained rotation written in the polar coordinate system and previously developed hypotheses for thin bodies. Within the framework of this mathematical model, boundary problems with applied values are formulated, which are solved in the final form. Further, the scheme of application of finite element method (FEM) is developed for the boundary problems of micropolar elastic beam with a circular axis with constrained rotation. The boundary problems stated above are solved by using the FEM and on the basis of an analysis obtained through the numerical results, the specific property of micropolarity of the material is established, that it raises the rigidity of the beam as compared with the classical theory. [ABSTRACT FROM AUTHOR]

The structural pseudo-β-titanium alloys found a wide application in aircraft and rocket building. However, while producing welded joints of pseudo-β-alloys applying method of fusion welding, the difficulties arise connected with change in the structure and formation of metastable phases in welded joint. In this paper, using the developed mathematical model of the TIG-welding process, the influence of thermal welding cycle on the weld shape, cooling rate and structure of welded joint metal of the pseudo-β-titanium alloy VT19 was investigated. A number of phases in the weld metal, heat-affected zone and base metal was established, the phase composition and its effect on the mechanical properties of welded joints were predicted. [ABSTRACT FROM AUTHOR]

In present paper the discontinuous solutions of equations for anti-plane problem of the elasticity theory for piece-wise space, formed by alternate junction of two heterogeneous layers with same thickness from different materials, with interphase doubly-periodic defects, when the displacements, as well as the stresses are discontinuous. Using these solutions the governing singular integral equations are written for two stated problems: the defect is the finite tunnel crack and the defect is finite tunnel crack with absolutely rigid thin inclusion welded to its one bank. The solutions of governing equations are built by the method of mechanical quadtratures. The numerical analysis are fulfilled and the character of changing of the displacements of edges of cracks is revealed, the stress intensity factor and contact stresses on junction line of the inclusion with matrix are determined depending on geometrical and physical and mechanical parameters. [ABSTRACT FROM AUTHOR]

Paper is devoted to the development of the mathematical model and analysis of the problem of corium melt interaction with low-temperature melting blocks in the passive protection systems against severe accidents at the NPP, which is of high importance for substantiation of the nuclear power safety, for building and successful operating of passive protection systems. In the third-generation reactors passive protection systems against severe accidents at the NPP are mandatory, therefore this paper is of importance for the nuclear power safety. A few configurations for the cooling blocks' distribution have been considered and an analysis of the blocks' melting and corium's cooling in the pool under reactor vessel have been done, which can serve more effective for further improvement of the safety current systems and for the development of new ones. The ways for solution of the problems and the methods for their successful elaboration were discussed. The developed mathematical models and the analysis performed in the paper might be helpful for the design of passive protection systems of the corium melt retention inside the containment after corium melt eruption from the broken reactor vessel. [ABSTRACT FROM AUTHOR]

Th e cost optimal design of the majority of distribution and servicing systems consists of decisions on a number and on the locations of facilities from which customers' demands are satisfied however, there are severe difficulties in solving exact procedures because the underlying mathematical model is NP-hard. Th ese decisions should respect some additional conditions as a limited capacity of located facilities. Th e objective is to minimize the overall costs of the system and to satisfy all customers' demands. In this paper, we enrich the set of constraints by a new requirement called sub-pool compactness. Th is property of customer subset influences the quality of vehicle routes s ubsequently formed in a sub-set of customers served by the same facility. Th is paper formulates the problem of the enriched capacitated facility location considering compactness condition, formalizes and studies the property of compactness and suggests the compound method solving this problem. [ABSTRACT FROM AUTHOR]

This paper presents the results of analytical studies on determination of vibration characteristics of cylinder liners of diesel engines based on the development and application of mathematical models. Mathematical relationships for cyclic deformations in a longitudinal cylinder sleeve for circumferential and radial directions have been developed. Sufficient convergence of the model with the results of practical measurements given in the literature has been shown. [ABSTRACT FROM AUTHOR]

The paper is devoted to the development and study of the mathematical model for corium melt interaction with low-temperature melting blocks in the passive protection systems (PPS) against severe accidents at the NPP, and learning the peculiarities of construction and operation of the PPS. The configurations of cooling blocks' distributions considered and the results of their work in the corium cooling pool are compared to the data of other PPS's conceptions. The conclusion is made that the models developed and the results obtained may be useful for constructing the PPS against severe accidents. [ABSTRACT FROM AUTHOR]

The paper discusses the general principle of energy conversion in open energy systems and presents the heat pump operating principle based on the molecular-kinetic theory. Various mechanisms of aircraft cooling during flight in the fixed atmosphere have been explained as well as the conditions in which electromagnetic systems can operate as heat pumps. It is stated that the aircraft in flight represents a heat pump. [ABSTRACT FROM AUTHOR]

This paper focuses on development of mathematical model for shielded distributed lowpass filter based on eight-terminal circuit theory. The proposed model is assessed using different initial data. Recommendations for the simulation of filtration are given. [ABSTRACT FROM AUTHOR]

Important nuclear power safety problem in touch with modeling of melted corium jet spreading inside the coolant pool is considered in the paper. It appears by development of the passive protection systems against severe accidents. The non-linear mathematical developed model is presented for the jet under reactor vessel pool for one of the perspective passive protection systems and the results of its analysis and studies are given. The performed analysis and the results of the numerical simulation done on the base of the model have allowed establishing the interesting behaviors of the system, which may be useful for the scientists, as well as the engineers-constructors of the passive protection systems against severe accidents. [ABSTRACT FROM AUTHOR]

In this paper the research results of English CRN railway noise propagation prediction model applicability possibilities in the conditions of Latvian railway are described. Experimental measurements of railway noise levels from different types of trains were done in the area or railway station Dole and were compared with the CRN model numerical calculation results. Relatively small difference between the experimentally and numerically gotten results proves the reasonability of investigation of the currently developed mathematical CRN model for railway noise propagation applicability possibilities in the conditions of Latvian railway. [ABSTRACT FROM AUTHOR]

In this paper the English national mathematical model for railway rolling stock noise propagation prediction is described. CRN mathematical model distinguishes with the ease of numerical calculation implementation. The basis for numerical calculation is the information about noise level, which is being produced by one wagon. Knowledge of the noise level, which is being produced by one wagon, gives the possibility to calculate the noise level, which is being produced by a rolling stock, consisting of N identical wagons. Various important parameters are taken into account during calculation, such as: wagon type, number of wagons in the rolling stock and the rolling stock movement speed, as well many correction coefficients. The final calculation result is the A weighted equivalent noise level value for the certain track segment and for the day's or night's period of time. As the model's imperfection it is needed to note the following: noise frequency characteristics, variety of wagon types in the rolling stock and weather conditions are not taken into account. Applicability of the given model is limited to the conditions of normal movement of trains on a railroad tracks, i.e. presence of such phenomena as a roughness of a railroad track, squeal of wheel pairs, flanging can raise the SEL level for up to 20 dBA. [ABSTRACT FROM AUTHOR]