Моделирование и оптимизация процесса перемещения грузов в логистической тран- портной системе

Network model and algorithm for the solution of optimization problem concerning cargo transportation process within multi-terminal network in accordance with several efficiency criteria of transportation system operation have been constructed and elaborated in the paper.The paper gives the algorithm that makes it possible to trace routes and cyclic routes of maximum carrying capacity of a transportation flow.Построена сетевая модель и разработан алгоритм решения задачи оптимизации процесса перемещения грузов в многополюсной трайспортной сети по нескольким критериям эффективности функционирования транспортной системы.Приведен алгоритм отыскания маршрутов и циклических маршрутов максимальной пропускной способности транспортного потока

Nanostructural states in Nb-Al mechanocomposite after conbined deformation treatment

Nanostructural states were investigated, that were formed in Nb-Al system-based mechanocomposite after combined deformation treatment that includes mechanical activation in a planetary ball mill and subsequent consolidation by torsion under pressure on Bridgman anvils. The formation of the layered structure, consisting of Nb and Al nanobands with width from several to several tens of nanometers was revealed. The structural states with high elastic curvature of crystal lattice and high level of local internal stresses found in Nb and Al subgrains were investigated by transmission electron microscopy

Evolution of microstructure and microhardness of dispersion-hardened V-Cr-Zr-W alloy during deformation by torsion under pressure

Results of the study of the microstructural evolution and microhardness changes of dispersion-hardened V–Cr–Zr–W alloy under severe deformation during torsion on Bridgman anvils are presented. Typical structural states and mechanisms of their formation are revealed for basic evolution stages as well as appropriate microhardness values are determined. It was shown that at true logarithmic strain values (e) in the range 0.7 ≤ e 2, the anisotropic submicrocrystalline structure is observed and the formation of two-level nanostructural states was found within grains. In the strain range (e) from 3 to 6.6, submicrocrystal sizes hardly change, but changes of two-level nanostructural state parameters are observed: the nanofragment size decreases and values of elastic curvature of the crystal lattice increases

Influence of temperature on microstructure parameters and microhardness of dispersion-hardened V–Cr–Zr–W alloy after deformation by torsion under pressure

Study of microstructure transformation and microhardness changes of dispersion-hardened V–Cr–Zr–W alloy after severe plastic deformation by torsion on Bridgman anvils and subsequent heat treatments was conducted. Basic stages of relaxation processes were revealed: at 800°C recovery processes take place and primary recrystallization begins; at 900°C primary recrystallization intensifies; in range of 950–1050°C collective recrystallization processes activate; at 1200°C secondary recrystallization starts. Microhardness measurement and comparison of its values with structural states features were conducted. Strengthening mechanisms and their contribution at various stages of defect substructure relaxation are discussed. It is shown that increase of thermal stability of V–Cr–Zr–W alloy microstructure is a consequence of the formation of high density of thermally stable Zr (O–N–C)-based nanoparticles

Positron annihilation spectroscopy of vacancy-type defects hierarchy in submicrocrystalline nickel during annealing

Positron annihilation and X-ray diffraction analysis have been used to study submicrocrystalline nickel samples prepared by equal channel angular pressing. In the as-prepared samples the positrons are trapped at dislocation-type defects and in vacancy clusters that can include up to 5 vacancies. The study has revealed that the main positron trap centers at the annealing temperature of deltaT= 20°C-180°C are low-angle boundaries enriched by impurities. At deltaT = 180°C-360°C, the trap centers are low-angle boundaries providing the grain growth due to recrystallization in-situ

Decomposition process in a FeAuPd alloy nanostructured by severe plastic deformation

The decomposition process mechanisms have been investigated in a Fe50Au25Pd25 (at.%) alloy processed by severe plastic deformation. Phases were characterized by X-ray diffraction and microstructures were observed using transmission electron microscopy. In the coarse grain alloy homogenized and aged at $450 ^{circ}\mathrm{C}$, the bcc \alpha-Fe and fcc AuPd phases nucleate in the fcc supersaturated solid solution and grow by a discontinuous precipitation process resulting in a typical lamellar structure. The grain size of the homogenized FeAuPd alloy was reduced in a range of 50 to 100nm by high pressure torsion. Aging at $450 ^{circ}\mathrm{C}$ this nanostructure leads to the decomposition of the solid solution into an equi-axed microstructure. The grain growth is very limited during aging and the grain size remains under 100nm. The combination of two phases with different crystallographic structures (bcc \alpha-Fe and fcc AuPd) and of the nanoscaled grain size gives rise to a significant hardening of the allo

СЕТЕВАЯ МОДЕЛЬ И АЛГОРИТМ РЕШЕНИЯ ЗАДАЧИ ОПТИМАЛЬНОГО РАCПРЕДЕЛЕНИЯ КАПИТАЛЬНЫХ ВЛОЖЕНИЙ ПРИ МОДЕРНИЗАЦИИ ПРЕДПРИЯТИЯ ТЕПЛОВЫХ СЕТЕЙ

The paper presents a problem statement, a developed mathematical model and proposed algorithm for  solving  optimization of capital  investments in modernization  (introduction of  automatic  controlsystems of thermal processes) of large systems of centralized heat supply which are based on application of network model.The formulated problem refers to the problems of combinatory (discrete) optimization. Methods of «branches and boundaries» or dynamic programming are applied nowadays for solving problems of this type. These methods are not considered as universal ones because they greatly depend on description  of  solution feasible area. As a result of it it is not possible to develop a universal software for solving any assignments which can be formulated as problems of combinatory optimization.The presented network model of the investigated problem does not have above-mentioned disadvantages and an algorithm is proposed for solving this problem which admits a simple programming realization. Представлена постановка задачи, разработана математическая модель и предложен алгоритм решения задачи оптимизации вложения капитальных средств в модернизацию (внедрение АСУ ТП) крупных систем централизованного теплоснабжения, основанные на применении сетевой модели.Сформулированная задача относится к задачам комбинаторной (дискретной) оптимизации. На сегодняшний день для решения такого класса задач, как правило, используются методы «ветвей и границ» или динамического программирования. Эти методы не являются универсальными, так как существенным образом зависят от описания области допустимых решений задачи. Следствием этого является невозможность создания универсального программного обеспечения для решения любых задач, которые могут быть сформулированы как задачи комбинаторной оптимизации.Представленная сетевая модель исследуемой задачи лишена указанных выше недостатков, а для ее решении предложен алгоритм, который допускает простую программную реализацию

СЕТЕВАЯ МОДЕЛЬ И АЛГОРИТМ РЕШЕНИЯ ЗАДАЧИ ОПТИМАЛЬНОГО РАСПРЕДЕЛЕНИЯ ТЕПЛОВЫХ НАГРУЗОК МЕЖДУ ТЕПЛОИСТОЧНИКАМИ ПРЕДПРИЯТИЯ ТЕПЛОВЫХ СЕТЕЙ

The paper  presents an algorithm for optimization of thermal load distribution among heat-sources in the system of centralized heat supply. The algorithm can be used while elaborating plans for development of heat supply systems in cities and settlements.Представлен алгоритм для оптимизации распределения тепловых нагрузок между теплоисточниками в системе централизованного теплоснабжения. Алгоритм может быть использован при разработке планов развития систем теплоснабжения городов и населенных пунктов

АЛГОРИТМ РЕШЕНИЯ ЗАДАЧИ ОПТИМИЗАЦИИ СТРУКТУРЫ И СОСТАВА СИСТЕМЫ ЦЕНТРАЛИЗОВАННОГО ТЕПЛОСНАБЖЕНИЯ

 The paper presents algorithms for structure optimization of centralized heat-supply systems in large cities due to higher heat loads and necessity for equipment change. The algorithms can be applied for elaboration of plans for development of heat supply in cities and human settlements.Представлены алгоритмы для решения задач оптимизации структуры централизованной системы теплоснабжения крупных городов в результате роста тепловых нагрузок и необходимости замены оборудования. Алгоритмы могут быть использованы при разработке планов развития систем теплоснабжения городов и населенных пунктов

Simulation and Optimization of Cargo Transportation Process in Logistic Transportation System

Network model and algorithm for the solution of optimization problem concerning cargo transportation process within multi-terminal network in accordance with several efficiency criteria of transportation system operation have been constructed and elaborated in the paper.The paper gives the algorithm that makes it possible to trace routes and cyclic routes of maximum carrying capacity of a transportation flow