Study of the properties of materials under complicated conditions of low cycle deformation

2021 ◽  
Vol 87 (7) ◽  
pp. 49-58
Author(s):  
N. A. Makhutov ◽  
М. M. Gadenin ◽  
О. F. Cherniavsky ◽  
A. О. Cherniavsky
Keyword(s):  
Initial Data ◽  
Equations Of State ◽  
Complex Loading ◽  
Time Factors ◽  
Point Of View ◽  
Theoretical Point ◽  
Operational Parameters ◽  
Practical Applications ◽  
Wide Range ◽  
Deformation Diagrams

Operational integrity of structures under complex combined modes of a loading depends on a significant number of combinations of operational parameters of thermomechanical impacts in part of loads, temperatures, duration, number of cycles, and deformation rates. The main laws governing the deformation of structural materials under complex loading are determined in conditions of combined standard, unified and special tests in laboratories. Using representative substantiations of physical and mechanical models for deformation diagrams in a wide range of loading conditions, taking into account the different scales of models, the structure of materials and the responsibility of structures, a stepwise consideration of the corresponding types of deformation is proposed: elastic, sign-variable flow, progressing accumulation of strains and their combination. At the same time, calculations of the structures can be carried out in the form of a hierarchical system in which each next level specifies the boundaries of permissible impacts towards expansion of the range of acting loadings, temperatures, rates and modes of deformation, which entails an increase in the bulk of the required initial data and complicates the calculations. The proposed methods of schematization of the physicomechanical properties and types of the equations of state for description of the deformation curves take into account the requirements of compactness of the initial data and the need of using both standard and unified methods for determining the characteristics of cyclic inelastic deformation and special methods as well. To describe the kinetics of deformation diagrams under aforementioned conditions both from the theoretical point of view and from the point of view of practical applications, power equations appeared most suitable; to reflect the role of the temperature factor exponential dependences should be used; whereas power dependences are useful to take into account time factors, strain rate, and conditions of two-frequency loading. The refined calculations at the higher and more complicated steps of the considered hierarchy providing the maximum possible use of the deformation and strength reserves of the materials and structures are to be based on the kinetic laws describing processes of low cycle deformation under complex modes of loading.

CONCEPTUAL DIRECTIONS OF THE TAXATION THEORIES DEVELOPMENT THROUGH THE REALIZING PRISM INTERESTS OF THE STATE AND TAXPAYERS

2021 ◽  
Vol 7 (1) ◽  
pp. 188-204
Author(s):  
Yulia G. TYURINA ◽  
Kristina A. BANNOVA
Keyword(s):  
Income Tax ◽  
The State ◽  
Personal Income ◽  
Point Of View ◽  
Theoretical Point ◽  
Personal Income Tax ◽  
State Budget ◽  
Theoretical Understanding ◽  
Direct Taxation ◽  
Wide Range

Nowadays, direct taxation of personal income is used in almost all countries of the world, and to this day there are various changes that shift the share of revenue from these taxes towards increasing the state budget. The significance of the personal income tax in economic policy is also due to the fact that it affects the interests of almost the entire population of the country. A variety of disputes constantly arise around the personal income tax, which can be explained by a wide range of taxpayers in various social strata. The ongoing transformations in the tax area predetermine the construction of the individuals taxation fair system as the fulfillment of one of the conditions for improving the living standards of the population. The relevance of the study lies in the need to reform the tax system in Russia, namely, the taxation of personal income, in order to implement the principle of social justice, as well as to satisfy the fiscal component of this tax, respectively, to fulfill the interests of participants in tax relations. The purpose of the article is a theoretical understanding of the conceptual directions of the taxation theories development through the prism of realizing the interests of the state and taxpayers in the taxation system of personal income. The subject of this research is the set of economic relations between the state and individuals, formed in the process of taxation of personal income in Russia. The methodological basis was the conceptual provisions of the theories of taxation, scientific methods and methods of analysis. The scientific novelty of the work lies in the fact that the results of the methodological analysis of the taxation theories development through the prism of realizing the state interests and taxpayers will make it possible to solve from a theoretical point of view the issue of interests balance achieving of all parties, which will contribute to the development of practical measures to achieve a decent standard of living for the population.

scholarly journals Theory of low mass stars, brown dwarfs and extra-solar giant planets

1997 ◽  
Vol 189 ◽  
pp. 331-340 ◽  
Author(s):  
Gilles Chabrier ◽  
Isabelle Baraffe
Keyword(s):  
Equations Of State ◽  
Galactic Disk ◽  
Brown Dwarfs ◽  
Reaction Rates ◽  
Point Of View ◽  
Giant Planets ◽  
Substantial Contribution ◽  
Mechanical And Thermal Properties ◽  
Low Mass Stars ◽  
Wide Range

Accurate modeling of the mechanical and thermal properties of very-lowmass stars (VLMS), Brown Dwarfs (BD) and Extra-solar Giant Planets (EGP) is of prior importance for a wide range of physical and astrophysical problems, from the fundamental physics point of view to the astrophysical and cosmological implications. They provide natural laboratories to test the different theories, equations of state, nuclear reaction rates, model atmospheres aimed at describing the physics of dense and cool objects. They represent the largest stellar population in the Galaxy, and thus provide a substantial contribution to the Galactic (disk) mass budget. Finally they represent one of the most intriguing questions in our understanding of the formation of star-like objects: are planet and star formation processes really different? Is there, and if so what is, a minimum mass for the formation of star-like objects? This field has blossomed recently with the discovery of several brown dwarfs (Nakajima et al, 1995; Rebolo et al., 1995) and numerous exoplanets since 51 Pegasi (Mayor and Queloz 1995; Mayor, this conference), which provide important information to challenge the theory.

scholarly journals Unified Mathematical Framework for Slicing and Symmetry Reduction over Event Structures

2014 ◽  
Vol 2014 ◽  
pp. 1-20
Author(s):  
Xinyan Gao ◽  
Yingcai Ding ◽  
Wenbo Liu ◽  
Kaidi Zheng ◽  
Siyu Huang ◽  
...  
Keyword(s):  
State Space ◽  
Permutation Group ◽  
Symmetry Reduction ◽  
Point Of View ◽  
Mathematical Framework ◽  
Theoretical Point ◽  
Practical Applications ◽  
Event Structures ◽  
Basic Facts ◽  
Equivalence Relationship

Nonclassical slicing and symmetry reduction can act as efficient structural abstract methods for pruning state space when dealing with verification problems. In this paper, we mainly address theoretical and algorithmic aspects for nonclassical slicing and symmetry reduction over prime event structures. We propose sliced and symmetric quotient reduction models of event structures and present their corresponding algorithms. To construct the underlying foundation of the proposed methodologies, we introduce strong and weak conflict concepts and a pair of mutually inverse operators and extend permutation group based symmetry notion of event structures. We have established a unified mathematical framework for slicing and symmetry reduction, and further investigated the translation, isomorphism, and equivalence relationship and other related basic facts from a theoretical point of view. The framework may provide useful guidance and theoretical exploration for overcoming verification challenges. This paper also demonstrates their practical applications by two cases.

scholarly journals On the Complexity of Fixed-Size Bit-Vector Logics with Binary Encoded Bit-Width

10.29007/cvnz ◽  
2018 ◽  
Author(s):  
Gergely Kovásznai ◽  
Andreas Fröhlich ◽  
Armin Biere
Keyword(s):  
Point Of View ◽  
Satisfiability Modulo Theories ◽  
Theoretical Point ◽  
Fixed Size ◽  
Practical Applications ◽  
Binary Encoding ◽  
Complexity Results ◽  
Bit Vector

Bit-precise reasoning is important for many practical applications ofSatisfiability Modulo Theories (SMT). In recent years efficient approachesfor solving fixed-size bit-vector formulas have been developed. Fromthe theoretical point of view, only few results on the complexity offixed-size bit-vector logics have been published. In this paper we showthat some of these results only hold if unary encoding on the bit-width ofbit-vectors is used. We then consider fixed-size bit-vector logics withbinary encoded bit-width and establish new complexity results. Our proofsshow that binary encoding adds more expressiveness to bit-vector logics,e.g. it makes fixed-size bit-vector logic even without uninterpretedfunctions nor quantication NExpTime-complete. We also show that undercertain restrictions the increase of complexity when using binary encodingcan be avoided.

Graphitic Nanoparticles

MRS Bulletin ◽  
1994 ◽  
Vol 19 (11) ◽  
pp. 39-42 ◽  
Author(s):  
D. Ugarte
Keyword(s):  
High Performance ◽  
Carbon Materials ◽  
Arc Discharge ◽  
Point Of View ◽  
Phase Changes ◽  
Laser Vaporization ◽  
Carbon Phase ◽  
Practical Applications ◽  
Wide Range ◽  
Melting Lead

Pure carbon materials, graphite and diamond, possess a wide array of interesting physical properties, and so attract a large spectra of interests and applications. Carbon microparticles (carbon black) and carbon fibers are widely used in practical applications including common materials (paints, inks, polymers, etc.) and high-performance composite materials.Carbon displays a remarkably rich and complex chemical behavior (three different possible hybridizations: sp1, sp2, and sp3). In particular, the covalent carboncarbon bond is one of the strongest in nature, and induces a high melting temperature (> 4000°C). The phase changes associated with unusually high temperatures and pressures as revealed in the carbon phase diagram, and the fact that the solid sublimates at low pressures before melting, lead to many experimental difficulties in the study of high-temperature properties of carbon materials. Experiments must therefore rely on transient melting, for example, laser vaporization or arc-discharge heating. This explains why fullerenes and related graphitic structures have only recently been discovered.From a fundamental point of view, the discovery of fullerenes has introduced new ideas about how carbon atoms bond. The curvature and closure of graphitic surfaces has become a standard concept in carbon chemistry, and recently a wide range of structures formed by curved graphitic networks has been observed. A surprising aspect of fullerene research is that these novel graphitic structures were found in well-known experiments, and that they had been overlooked for so many years.This article will describe recent progress in the generation and physical characterization of graphitic nanoparticles, or multishell fullerenes. The lack of an efficient method for producing, as well as a method for purifying these particles makes it difficult to characterize them and to develop possible applications.

Practical applications of the analysis of the environment of functioning (Data envelope Analysis) to the solution of problems of ecological management

2019 ◽  
Author(s):  
Светлана Ратнер ◽  
Svyetlana Ratnyer
Keyword(s):  
Functional Dependence ◽  
Russian Language ◽  
Point Of View ◽  
Mathematical Economics ◽  
Wide Audience ◽  
Envelope Analysis ◽  
Practical Applications ◽  
Wide Range ◽  
Dea Models ◽  
Data Envelope Analysis

Methodology of analysis of the operating environment (in the English version — Data envelope Analysis) for the last 30 years is one of the most popular and dynamically developing areas in operations research. Whereas previously the DEA models were known only to professional mathematicians, in recent years there have been many new and interesting applications of the DEA methodology to solving a wide range of management problems from various areas of management. The popularity of DEA is explained, on the one hand, by the fact that this methodology is based on the fundamental principles of mathematical Economics, which allows to obtain modeling results that are quite easily interpreted from the point of view of the economist. On the other hand, the advantage of DEA is the ability to model the activities of economic agents in the absence of any assumptions about the form of functional dependence between the inputs consumed by them and the outputs produced, i.e. to consider the activity of any production system as a "black box". However, the methodology of the DEA is still little known in Russia, as indirectly evidenced by the lack of generally accepted Russian-language terminology in this area. The few publications devoted to DEA, as a rule, are written for specialists with serious mathematical training. The monograph is intended to acquaint a wide audience of students, undergraduates, postgraduates, researchers and practitioners from the field of management with the possibilities of using the DEA methodology for solving a wide class of practical problems. A feature of the monograph is the focus on a relatively new class of DEA models specifically designed to solve problems in the field of environmental management.

scholarly journals Analysing the Utilisation Effectiveness of Mining Machines Using Independent Data Acquisition Systems: A Case Study

Energies ◽  
2019 ◽  
Vol 12 (13) ◽  
pp. 2505 ◽  
Author(s):  
Jarosław Brodny ◽  
Magdalena Tutak
Keyword(s):  
Raw Materials ◽  
Digital Data ◽  
Independent Data ◽  
Operational Parameters ◽  
Mining Sector ◽  
Data Archiving ◽  
Practical Applications ◽  
Unit Costs ◽  
Automation Systems ◽  
Wide Range

Growing competition in the market for energy raw materials needed for power generation has led to an increasing number of measures being undertaken in the mining sector to reduce the unit costs of mining production. One of the areas that offer considerable savings in this regard is the utilisation of the technical resources owned by mines. This article is therefore focussed on analysing the utilisation effectiveness of these machines, based on the data recorded by industrial automation systems, as well as on measurements from independent surveying and chemical analysis of the excavated material’s quality. For this purpose, a methodology was developed to use the data about the operational parameters of the machines in order to analyse the effectiveness of their utilisation. It was assumed that the reliability of this assessment would depend mainly on the quality of the data used to conduct it. It was also assumed that using independent data sources for the analysis would provide objective and reliable information on the operation of the machines, devoid of any subjective feelings of the personnel or other factors. The developed methodology, based on a modified Overall Equipment Effectiveness (OEE) model, was used to analyse four machines that comprise the automated longwall system. Values were determined for each machine, including their availability, performance and product quality. This, in turn, made it possible to determine a total effectiveness indicator, based on a modified Overall Equipment Effectiveness (OEE) model, for the particular machines and the entire technical systems they form. The obtained results were used to assess the effectiveness of their utilisation and recommend corrective measures aimed at improving this metric. Moreover, the analysis results made it possible to assess the utilisation status of the machines in question. They also served as the basis for determining further lines of research, the purpose of which is to improve the effectiveness of the mining sector. The obtained results indicated that this process requires the wide application of IT tools, especially for data archiving and analysis. These tools, along with the developed model and methodology based on the analysis of large volumes of digital data, are in accord with the activities related to the implementation of Industry 4.0 idea in mining. It is the authors’ opinion that the material at hand should find a wide range of practical applications in supporting the management of technical resources within the mining sector.

Theoretical Parametric Study of Wrap-Around Heat Pipe (WAHP) in Air Conditioning Systems

2019 ◽  
Vol 27 (01) ◽  
pp. 1950004
Author(s):  
Mridul Sarkar
Keyword(s):  
Air Temperature ◽  
Mass Conservation ◽  
Point Of View ◽  
Outlet Temperature ◽  
Theoretical Point ◽  
Performance Study ◽  
Operational Parameters ◽  
Humidity Ratio ◽  
Comparative Performance ◽  
Cooling Coils

Warp-around heat pipes (WAHP) belong to a special class of recuperative heat exchangers that transfer heat from inlet to outlet locations via thermal gradient, without using any energy. In the present work, effects of various mechanical parameters on the performance of a WAHP dehumidifier system that are based on the underlying principles of heat and mass conservation are presented primarily from a theoretical point of view. A simplified methodology pertaining to wet cooling coils is applied here for defining the case of moisture condensation during precooling process at WAHP evaporator. Inlet air temperature, inlet humidity ratio, air mass flow rate, dehumidifier outlet temperature and effectiveness are the main operational parameters considered in this study. On the other hand, comparative performance study of the WAHP system is done through an other set of thermodynamic parameters like the supply air temperature, supply humidity ratio, specific coil load and recovered enthalpy. The subtle variations in these factors against the operational parameters not only help in stipulating functional characteristics of the WAHP but also allow HVAC designers to make informed decisions for system design and performance without relying entirely on manufacturer’s equipment data.

scholarly journals General considerations on the theory of the separation of H 1 and H 2 by electrolysis of water

1934 ◽  
Vol 144 (852) ◽  
pp. 452-466 ◽  
Keyword(s):  
A Priori ◽  
Point Of View ◽  
Theoretical Point ◽  
High Current ◽  
Hydrogen Electrode ◽  
Effective Separation ◽  
A Value ◽  
Rates Of Evolution ◽  
Wide Range ◽  
Current Densities

1. The Facts .―In a solution of NaOH (or KOH) with nickel (perhaps with other) electrodes and at high current densities of the order of 1 ampere per cm. 2 of electrode the observed rates of evolution E 1 and E 2 of H 1 and H 2 at the cathode obey an equation of the type E 1 /E 2 = q D 1 /D 2 , (1) where D 1 and D 2 are the relative concentraction of the H 1 and H 2 atoms in the water as a whole. The coefficient q has been shown to be independent of D 1 /D 2 over a very wide range of relative concentrations. Under the conditions most favourable to separation, which appear to be those just specified, q can have a value as great as 6, or perhaps 7. With other metals than nickel for the electrodes and with lower current densities the factor q may fall to a value well below 2 or even to a value so nearly unity that no effective separation occurs. The dependence of q (if any) on the temperature of the solution is not known. 1.1. The Arguments .―The facts have already been commented on by Polanyi from the theoretical point of view. He has been led to conclude from them that the separation is to be attributed to a difference of " over potential" for the deposition of H 1 and H 2 ions on the cathode, and consequently that Gurney's theory of the over-potential of the hydrogen-electrode at low current densities (as measured, for example, by Bowden) must be discarded. These conclusions if correct and unavoidable are of the greatest importance. It is most general way possible, in order to see that no types of mechanism have been overlooked which could lead to the observed results. When this is done it is found that the mechanism discussed by Polanyi which refers the separation to differences of over-potential is not the only mechanism which must be held possible a priori . The observed separation could perfectly well occur by a mechanism consistent with Gurney's theory. It does not yet appear to be possible to decide confidently between the two possibilities on experimental grounds.

scholarly journals Decidable Reasoning in Terminological Knowledge Representation Systems

1993 ◽  
Vol 1 ◽  
pp. 109-138 ◽  
Author(s):  
M. Buchheit ◽  
F. M. Donini ◽  
A. Schaerf
Keyword(s):  
Knowledge Representation ◽  
Knowledge Bases ◽  
Point Of View ◽  
Theoretical Point ◽  
General Technique ◽  
Practical Applications ◽  
Constraint Systems ◽  
Representation Systems ◽  
Concept Languages ◽  
Knowledge Representation Systems

Terminological knowledge representation systems (TKRSs) are tools for designing and using knowledge bases that make use of terminological languages (or concept languages). We analyze from a theoretical point of view a TKRS whose capabilities go beyond the ones of presently available TKRSs. The new features studied, often required in practical applications, can be summarized in three main points. First, we consider a highly expressive terminological language, called ALCNR, including general complements of concepts, number restrictions and role conjunction. Second, we allow to express inclusion statements between general concepts, and terminological cycles as a particular case. Third, we prove the decidability of a number of desirable TKRS-deduction services (like satisfiability, subsumption and instance checking) through a sound, complete and terminating calculus for reasoning in ALCNR-knowledge bases. Our calculus extends the general technique of constraint systems. As a byproduct of the proof, we get also the result that inclusion statements in ALCNR can be simulated by terminological cycles, if descriptive semantics is adopted.

Sign in / Sign up

Export Citation Format

Share Document