152 research outputs found
The choice of poles rational number of the traction induction motors under different energy efficiency requirements for the drive
Выполнен сопоставительный анализ электромеханических характеристик тяговых асинхронных двигателей с различным числом полюсов при различных фиксированных превышениях температуры обмотки статора. Предложены критерии, формирующие множество Паретооптимальных решений. Представлен метод выбора наилучшего решения из совокупности Паретоэффективных альтернатив. Установлена низкая эффективность «бубликообразной» конструкции с большим числом пар полюсов.The report made a comparative analysis of the electromechanical characteristics of traction induction motors with different numbers of poles at various fixed overtemperature of the stator winding. The criteria that form the set Pareto-optimal solutions are proposed. The method of choosing the best solutions from the set of Pareto-efficient alternatives is described. There is a low efficiency of "donut-shaped" design with a large number of pole pairs is founded
Thermodynamics and Phase Transitions of Electrolytes on Lattices with Different Discretization Parameters
Lattice models are crucial for studying thermodynamic properties in many
physical, biological and chemical systems. We investigate Lattice Restricted
Primitive Model (LRPM) of electrolytes with different discretization parameters
in order to understand thermodynamics and the nature of phase transitions in
the systems with charged particles. A discretization parameter is defined as a
number of lattice sites that can be occupied by each particle, and it allows to
study the transition from the discrete picture to the continuum-space
description. Explicit analytic and numerical calculations are performed using
lattice Debye-H\"{u}ckel approach, which takes into account the formation of
dipoles, the dipole-ion interactions and correct lattice Coulomb potentials.
The gas-liquid phase separation is found at low densities of charged particles
for different types of lattices. The increase in the discretization parameter
lowers the critical temperature and the critical density, in agreement with
Monte Carlo computer simulations results. In the limit of infinitely large
discretization our results approach the predictions from the continuum model of
electrolytes. However, for the very fine discretization, where each particle
can only occupy one lattice site, the gas-liquid phase transitions are
suppressed by order-disorder phase transformations.Comment: Submitted to Molecular Physic
Thermophysical characteristics of radioactive graphite - Water vapor system
The article considers thermophysical characteristics of radioactive graphite - water vapor system in temperature range 373-3273K. The research was made by thermodynamic modeling method using TERRA software. We determined 4 temperature intervals in which changes of thermophysical characteristics of radioactive graphite - water vapor system occur. © 2017 The Authors, published by EDP Sciences
Historical and statistical data on the development of the domestic alcoholic beverages industry
The method of historical and statistical data analysis makes it possible to identify development and characteristic patterns, both temporary and permanent, production criteria for various branches of the food industry. The application of this method made it possible to trace formation of the alcohol industry inRussiaand identify critical historical events that influenced its development. The article presents and analyzes statistical data on the production of the main types of alcoholic beverages industry since 1913
Thermal characteristics of the radioactive graphite-CuO-Na2CO3-K2CO3-NaCl-KCl system in argon atmosphere
The article considers thermal characteristics of the radioactive graphite-CuO-Na2CO3-K2CO3-NaCl-KCl system in argon atmosphere. Thermodynamic calculations were carried out in the Terra program. Four temperature ranges with changes of thermal characteristics of the radioactive graphite-CuO-Na2CO3-K2CO3-NaCl-KCl system in argon atmosphere have been determined. © Published under licence by IOP Publishing Ltd
Thermodynamics of Electrolytes on Anisotropic Lattices
The phase behavior of ionic fluids on simple cubic and tetragonal
(anisotropic) lattices has been studied by grand canonical Monte Carlo
simulations. Systems with both the true lattice Coulombic potential and
continuous-space electrostatic interactions have been investigated. At
all degrees of anisotropy, only coexistence between a disordered low-density
phase and an ordered high-density phase with the structure similar to ionic
crystal was found, in contrast to recent theoretical predictions. Tricritical
parameters were determined to be monotonously increasing functions of
anisotropy parameters which is consistent with theoretical calculations based
on the Debye-H\"uckel approach. At large anisotropies a two-dimensional-like
behavior is observed, from which we estimated the dimensionless tricritical
temperature and density for the two-dimensional square lattice electrolyte to
be and .Comment: submitted to PR
Effect of the entropy on the shear viscosity of metallic glasses near the glass transition
We measured the shear viscosity of 14 metallic glasses differing with their
mixing entropy . It is found that the viscosity at the glass
transition temperature significantly increases with .
Using calorimetric data, we calculated the excess entropy of all glasses
with respect to their maternal crystalline states as a function of
temperature. It is shown that the excess entropy both at room
temperature and at \textit{decreases} with . It is
concluded that glasses with "high mixing entropy" correspond
to MGs with \textit{low} excess entropy . The origin of the increased
shear viscosity at of glasses with high is determined by
their reduced excess entropy .Comment: 12 pages, 4 Figure
Relation of the thermodynamic parameter of disordering with the width of structure factor and defect concentration in a metallic glass
In this work, we show that above the glass transition there exists a strong
unique interrelationship between the thermodynamic parameter of disorder of a
metallic glass derived using its excess entropy, diffraction measure of
disorder given by the width of the X-ray structure factor and defect
concentration derived from shear modulus measurements. Below the glass
transition, this relationship is more complicated and depends on both
temperature and thermal prehistory.Comment: 6 pages, 2 Figure
Critical behavior of the fluctuation heat capacity near the glass transition of metallic glasses
The high-frequency shear modulus of five Zr-, Pd-, Cu-based conventional and
two high-entropy bulk metallic glasses was measured in a wide temperature range
up to the beginning of crystallization. Using these data and general
thermodynamic relations, the "fluctuation" heat capacity
determined by local structural fluctuations in the defect regions is introduced
and calculated. It is found that temperature dependence for all
metallic glasses has a large peak located slightly below or above the glass
transition temperature but clearly lower than the crystallization onset
temperature. The form of this peak resembles the characteristic -peak
typical for order-disorder phase transitions. It is suggested that this -peak reflects certain underlying critical phenomenon. The critical
temperature (peak temperature) and corresponding critical index
are determined. Averaged over all seven metallic glasses under investigation in
the initial and relaxed states, the critical index . The results
obtained indicate that the fluctuations of thermal energy near the glass
transition bear the marks of a continuous phase transition. However, the
derived critical index is between those corresponding to a second-order phase
transition () and a critical transition characterized by a
tricritical point ().Comment: 18 pages, 4 figure
CALCULATION OF COMPRESSIBILITY IN MOLTEN MIXTURES OF POTASSIUM HALIDES BY MOLECULAR DYNAMICS SIMULATION
Calculation of the isothermal compressibility of molten potassium halides by the molecular dynamics method is carried out. It is shown that as the radii differences between the anions of the constituent binary mixture increase, the interparticle interactions in the system increase. This is manifested in a greater deviation from the additivity of the isothermal compressibility of the KCl-KI mixture as compared to the KBr-KI mixture
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