On the Method of Calculating Diffusion Vacuum Pump Stage Pumping Parameters

2021 ◽  
pp. 85-93
Author(s):  
K.E. Demikhov ◽  
A.A. Ochkov
Keyword(s):  
Mathematical Models ◽  
Science And Technology ◽  
Practical Importance ◽  
Vacuum Pump ◽  
Practical Significance ◽  
Relative Simplicity ◽  
Diffusion Pump ◽  
Pump Stage ◽  
Working Processes

At present, steam jet vacuum pumps are widely used in various fields of science and technology due to a number of advantages, e.g., reliability, relative simplicity of design, and manufacturability, over other pumping means. The paper analyzes the existing mathematical models of working processes, methods for calculating the pumping parameters of steam-jet vacuum pumps. The problem of improving these methods, which are used in the design, is still urgent. The study attempts to further develop the models in order to increase their practical significance for the pumps design: in particular, the processes of pumping by the first stages of a diffusion pump are considered, since it is they that determine the efficiency of the pump as a whole. Analytical dependences for calculating the main pumping parameters of widely used diffusion vacuum pumps are presented. The obtained equations are a certain clarifying correction of the known provisions on this topic. Findings of research are of practical importance for the design of modern steam-jet vacuum pumps

scholarly journals Infrastructure Public–Private Partnership (PPP) Investment and Government Fiscal Expenditure on Science and Technology from the Perspective of Sustainability

2021 ◽  
Vol 13 (11) ◽  
pp. 6193
Author(s):  
Chang Liu
Keyword(s):  
Science And Technology ◽  
Public Private Partnership ◽  
Practical Significance ◽  
Government Investment ◽  
Private Partnership ◽  
The Public ◽  
Governance Environment ◽  
Good Government ◽  
Investment Structure ◽  
Fiscal Expenditure

In the environment of the continuous development of the Public–Private Partnership (PPP) model, China’s “dual circulation” development pattern orientation and “new normal” economic development reform provide the foundation for the development of the PPP model in the field of infrastructure. A good government investment structure and governance environment will help to improve the financial sustainability of infrastructure investment. This paper studies the mechanism of the relationship between fiscal expenditure on science and technology and the development of infrastructure PPP models based on the data of provincial PPP projects in the World Bank database and carries out an empirical analysis. The results show that the positive effect of government fiscal expenditure on science and technology and the development of the infrastructure PPP model in local regions is significant. In addition, intergovernmental competition within the political system of China will have a restraining effect on this relationship. This has certain theoretical and practical significance for the construction and implementation of the mechanism underlying intergovernmental behavior and the infrastructure PPP model.

scholarly journals A Set of Economic and Mathematical Models for Assessment of Agricultural Crop Cultivation Technologies

2019 ◽  
Vol 8 (2) ◽  
pp. 3829-3833
Keyword(s):  
Mathematical Models ◽  
Assessment Model ◽  
Information Support ◽  
Practical Significance ◽  
Production Cycle ◽  
Agricultural Crop ◽  
Crop Cultivation ◽  
Software Complex ◽  
Technological Processes ◽  
Crop Farming

Research objectives. The paper describes the process of development of a set of mathematical models for assessment of agricultural production technologies to be used as the basis of a software complex module for managing technological processes in crop farming. The reported study was funded by RFBR according to the research project № 18-37-00148. Methods. Given the specifics of management in agriculture, it is worth noting that the lack of objective information across the production cycle in crop farming and the subsequent misalignment with an optimum technology results in overshooting labour and material costs, lost profits for the enterprise or even losses. These issues have to be addressed through advanced studies of economic and mathematical models and methods for analysis and assessment of economic efficiency of agricultural crop cultivation technologies and the development of a comprehensive automated information support system for decision-making in crop farming management. Results. A methodology is proposed for selecting economically efficient technological processes in crop farming, involving the sequential application of results obtained through the analysis of technological process criteria by the methods of binary decision matrices, cobweb diagrams and the matrix assessment model, taking into account their orientation at the economic performance of crop farming. Practical significance and applicability of results. The authors developed a complex of software and information support and assessment of technological processes in crop farming, with experimental trials showing improved efficiency of crop farming production through the well-reasoned selection of agricultural crop cultivation technologies.

TRENDS IN THE DEVELOPMENT OF REACTIVE FIRE PROTECTION (LITERATURE REVIEW)

2021 ◽  
pp. 75-90
Author(s):  
Lyubov Vakhitova ◽  
◽  
Nadiya Taran ◽  
Konstantin Kalafat ◽  
◽  
...  
Keyword(s):  
Literature Review ◽  
Fire Protection ◽  
Flame Retardants ◽  
Practical Importance ◽  
Fire Retardant ◽  
Steel Structures ◽  
Life Time ◽  
Practical Significance ◽  
Protection Measures ◽  
The Cost

Purpose. Identification of the main directions of evolution of scientific researches concerning development and improvement of fire protective reactive coatings of intumescent type for steel constructions. Methods. Analysis of literature sources, study and generalization of information, classification and modeling of chemical processes. Results. As a result of the performed researches it has been shown that of all the developed reactive fire protection systems for increasing the fire resistance of steel structures the intumescent composition of ammonium polyphosphate/ pentaerythritol / melamine / polymer is the most widespread and economically justified. To reduce the cost of fire protection measures, it is necessary to improve the coatings of the intumescent type in the following main areas: increasing of fire protection efficiency with a decrease in the thickness of the fire protection layer; prolongation of life time with strengthening of resistance to external factors; reducing the cost of the prescription composition of intumescent paint due to the use of nanomaterials. Scientific novelty. It has been established that nanoclays, nanooxides of metals and silicon, LDH compounds and their analogues should be considered the most promising and multifunctional. The presence of nanomaterials in intumescent compositions allows to increase the environmental parameters of fire-retardant treatment due to the rejection of halogen flame retardants, boron compounds, formaldehyde resins. In addition, the presence of nanocompounds in intumescent coatings significantly reduces smoke in fire. Practical significance. The conclusions obtained from the literature review are of practical importance for the development of new approaches to the design of fire-fighting materials with improved performance through the use of nanomaterials, which provides a strong fire retardant foam char layer and provides rigidity of the insulation frame.

scholarly journals The Use of the Foresight Methods in Developing an Algorithm for Conducting Qualitative Examination of the Research Activities Results on the Example of the Republic of Kazakhstan

Mathematics ◽  
2020 ◽  
Vol 8 (11) ◽  
pp. 2024
Author(s):  
Rinat Zhanbayev ◽  
Saule Sagintayeva ◽  
Abildina Ainur ◽  
Anton Nazarov
Keyword(s):  
Higher Education ◽  
Human Resources ◽  
Systematic Approach ◽  
Science And Technology ◽  
Patent Analysis ◽  
The State ◽  
Practical Significance ◽  
Innovative Development ◽  
Research Activities ◽  
The Republic

In modern conditions, it is interesting to study foresight as an effective tool for identifying new strategic scientific directions. Its purpose is to develop an algorithm for conducting qualitative expertise in the application of the foresight methods with the ability to integrate forecast estimates. Currently, the vast majority of research activities results do not contribute to the innovative development of the state. To solve this problem, it is necessary to ensure a stable systemic relationship between specific sectors of the economy and higher education. The algorithm is developed on the basis of a systematic approach to the foresight methods and the use of the methods of bibliometrics, scientometrics, patent analysis and forecasting. The results and conclusions of this study are: an algorithm has been developed for conducting qualitative examination of the results of scientific activities in order to increase its practical significance, in which the authors propose the foresight methods as the most optimal tool for choosing priority areas of science and technology. Putting this approach into practice will make it possible to increase the efficiency of the foresight methods by both reducing time costs, and rationally using monetary and human resources.

scholarly journals ЗАБЕЗПЕЧЕННЯ РЕЗУЛЬТАТИВНОСТІ ОБЛІКУ ТА АУДИТУ СИСТЕМИ УПРАВЛІННЯ ВИТРАТАМИ ПІДПРИЄМСТВ АЕРОКОСМІЧНОЇ ГАЛУЗІ

2020 ◽  
pp. 58-64
Author(s):  
Г. С. Ліхоносова ◽  
В. Г. Бондаренко
Keyword(s):  
Management System ◽  
Cost Management ◽  
Practical Importance ◽  
Aerospace Industry ◽  
Cost Accounting ◽  
Production Costs ◽  
Practical Significance ◽  
Main Hypothesis ◽  
Cost Management System ◽  
The Cost

The article considers the organization of the cost management system as an object of accounting, the factors that affect the cost and effectiveness of methods of audits of costs for the production of aerospace products. The purpose of the article is to present the issues of accounting and analytical support and audit of the cost management system in the aerospace industry with a focus on the features of accounting and audit of the cost system in the aerospace industry. The methodological basis of the study is a number of scientific methods, including methods of empirical research - comparison, methods of theoretical knowledge – formalization and general research methods - analysis, synthesis and grouping. The main hypothesis of the study was the assumption that the accounting and analytical support of cost management system is influenced by various factors, including: type of production, features of its organization, product range, enterprise management structure, organization of accounting by places and centers of responsibility, cost accounting methods and costing products and the level of automation of accounting work. Presenting main material. It was found that cost accounting occupies a decisive place in accounting and analytical support and audit procedures. The formation of accounting and analytical support of the cost management system in the aerospace industry largely depends on the factors influencing the formation of the cost and the organization of the analysis of the component costs of enterprises. The organization of synthetic and analytical accounting of production costs should ensure: reflection of all performed operations on costs, appropriate distribution of costs by objects of accounting and calculation objects, determination of production costs, timely receipt of necessary information for management purposes. The originality and practical significance of the study is confirmed by the analysis of the possibility of auditing the enterprises of the aerospace industry. The proposed method of accounting and costing is of practical importance and can be used for other enterprises in the aerospace industry. Conclusions and prospects for further research. The method of cost accounting presented in the article is of practical importance for the enterprises of the aerospace industry. Further research will be aimed at improving the accounting and analytical support and algorithms for audits of the cost management system in the aerospace industry

scholarly journals Mathematical models and methods of numerical investigation of processes which accompany aircraft icing

2021 ◽  
Vol 33 (5) ◽  
pp. 237-248
Author(s):  
Ivan Alekseevich Amelyushkin ◽  
Maksim Aleksandrovich Kudrov ◽  
Alexey Olegovich Morozov ◽  
Andrey Sergeevich Shcheglov
Keyword(s):  
Numerical Modeling ◽  
Mathematical Models ◽  
High Performance ◽  
Practical Importance ◽  
Particle Dynamics ◽  
Software Systems ◽  
Aircraft Icing ◽  
Properties Of Coatings ◽  
Practical Applications ◽  
Physical And Mathematical Models

The study of aircraft icing modes, in which it is necessary to take into account the effect of droplet crushing, is of great interest in calculating the icing of aircraft, optimizing the hydrophobic and anti-icing properties of coatings, and is relevant in a number of other practical applications. Of great practical importance is the development of high-performance methods for calculating the interaction of aerosol flows with a solid. This work is devoted to the development of a model of particle dynamics, as well as a model of fragmentation of supercooled droplets of an aerosol flow during its interaction with the surface of a streamlined body. Developed physical and mathematical models can be used in software systems for numerical modeling of aircraft icing.

scholarly journals Entrepreneurship in national economics: significance and potential of development

2020 ◽  
Vol 9 (27) ◽  
pp. 428-435
Author(s):  
I. S. Pinkovetskaia ◽  
N. R. Aleksandrova ◽  
O. N. Mingazova
Keyword(s):  
Comparative Analysis ◽  
Mathematical Models ◽  
Practical Significance ◽  
Social Significance ◽  
Entrepreneurship Development ◽  
The Social ◽  
Global Entrepreneurship

The purpose of the study was to develop proposals for the use of two comprehensive indexes to assess the social significance and the existing potential for entrepreneurship development in different countries. The study used information provided in the report on the Global entrepreneurship monitoring project. At the same time, the opinions of residents of 48 countries for 2018 were considered. The first index included four indicators, and the second index included five indicators. Mathematical models were developed and the values of these two complex indexes were calculated. The average values of the indexes and their ranges of change for most countries are determined. Lists of countries with high and low index values are given. A comparative analysis of the values of complex indexes typical for Russia and other countries is presented. The results of research are new and original, have scientific and practical significance.

scholarly journals ОСНОВНІ ТЕНДЕНЦІЇ ПРОСТОРОВОЇ ОРГАНІЗАЦІЇ ТА МЕБЛЮВАННЯ ШКІЛЬНОГО КЛАСУ У ПЕРШІЙ ТРЕТИНІ XX СТОРІЧЧЯ

2019 ◽  
pp. 64-76
Author(s):  
Д. Ю Косенко
Keyword(s):  
Public Schools ◽  
20Th Century ◽  
Western Europe ◽  
Progressive Education ◽  
Practical Importance ◽  
Spatial Arrangement ◽  
Practical Significance ◽  
Learning Space ◽  
Educational Design ◽  
School Learning

Purpose of the article is to discover features of the arrangement and furnishing of the school learning space in the 1st third of the 20th century. Methodology is based on the historical and evolutionary princsple. Source base includes scientific, technical and popular literature of the period, material artefacts. Results. At the turn of 20th century strong movement for renewing of pedagogy rises; the movement based on child-centered principle is known as “reform-pedagogy” in Europe and “progressive education” in the USA. Progressive educators came to conclude that new pedagogical approaches also demand changes in the classroom equipment. Furnishing and spatial arrangement of the classroom are treated not only from the point of working convenience, but as essential part of pedagogical concept and, even more, as social and cultural phenomena. New types of classroom furniture are developed and improved, namely desks with horizontal or variable-sloped worksurface and freestanding students’ chairs, not attached to desks. Innovations in spatial arrangement are based on two approaches: functional zoning on the subject or thematic basis and flexible arrangement of pupils’ workplaces. Mentioned tendencies at that time are improved in alternative or experimental schools. Attempts to rearrange the spaces of public schools basing on mentioned approaches started in the USSR in the late 1920th, but were stopped in early 1930th, when experiments in the Soviet educational system were banned. Scientific novelty. Main tendencies in classroom spatial arrangement and furnishing in the 1st third of the 20th century are analized and summarized in the context of the progressive education movement. The furnishing of Soviet (including Ukrainian) schools of the period is discussed; similarities and differences in the development of classroom space in USSR, Western Europe and USA are revealed. Practical significance. Review of the development of the school learning space in 1st third of the 20th century contributes to the holistic picture of educational design as a historical and cultural phenomenon. Understanding the patterns of historical development of the educational space is of practical importance for the conceptualization and prediction of trends in modern educational design.

FIRE PROTECTIVE EFFICIENCY OF INTUMESCENT TYPE EPOXIDE COATING

2021 ◽  
pp. 143-153
Author(s):  
Lyubov Vakhitova ◽  
◽  
Nadiya Taran ◽  
Konstantin Kalafat ◽  
Volodymyr Bessarabov ◽  
...  
Keyword(s):  
Epoxy Resin ◽  
Epoxy Resins ◽  
Flame Retardants ◽  
Practical Importance ◽  
Fire Retardant ◽  
Practical Significance ◽  
Protective Efficiency ◽  
Intumescent Coating ◽  
Polymer Component ◽  
Intumescent System

Purpose. The purpose of this work is to study the thermal degradation of epoxy polymers and nanocomposites based on them in a fire retardant intumescent coating having a composition – ammonium polyphosphate / melamine / pentaerythritol. Methods. Thermogravimetric studies have been performed on the device “Thermoscan-2”, fire tests were performed by the method of “Bunsen burner”. Results. The influence of the structure of epoxy resin as a polymer component of the intumescent system on oxidative thermal destruction and fire retardant efficiency of reactive coating has been researched. The obtained results allow us to state that the best result has been demonstrated by Araldite GY 783 – epoxy resin of bisphenols A/F with a reactive solvent. The thermal properties of various epoxy resins and nanocomposites based on them with organomodified montmorillonite have been studied. It was found that montmorillonite in the nanocomposite increases the decomposition temperature of epoxy resin. Scientific novelty. It has been shown that the variation of the polymer component of the intumescent coating has little effect on the swelling rate, but the fire retardant efficiency of the intumescent composition containing epoxy resin of bisphenols A/F is higher than the same characteristic for the composition based on epoxy resin of bisphenol A. It has been established that the exclusion of pentaerythritol from the formulation of the epoxy intumescent system causes the formation of a more regular and durable char insulation layer. It has been proved that the use of additional, including nanostructured flame retardants, namely, modified montmorillonite, can increase the fire retardant efficiency of the coating. Practical significance. The obtained results are of practical importance for the development of new scientific approaches to the design of fire-fighting materials with improved performance characteristics through the use of polymers that provide the construction of a thermostable thermal insulation char layer. Through a series of systematic tests, it has been demonstrated that the use of nanoclay and nanocomposites based on epoxy resins allows to improve the formulations of intumescent coatings with high performance with the help of budget nanotechnologies.

Control of Dynamic Objects in the Conditions of Uncertainty in the Point Sliding Mode

2019 ◽  
Vol 20 (12) ◽  
pp. 714-722
Author(s):  
G. A. Rustamov ◽  
M. B. Namazov ◽  
A. Y. Gasimov ◽  
R. G. Rustamov
Keyword(s):  
Finite Number ◽  
Sliding Mode ◽  
Practical Importance ◽  
Practical Significance ◽  
Switching Frequency ◽  
Time Interval ◽  
Initial State ◽  
Classical Formulation ◽  
Sliding Motion ◽  
Switching Line

There is development of the well-known sliding mode, which in the classical formulation didn’t find the development to be applied to control systems discussed. Alternatively, there is method of organizing one of the uniformity of the sliding mode called the "point sliding mode" proposed. The distinctive feature of this mode is that here the control gaps occur at time-equal points of the switching line (hyperplane) which allows the origin of coordinates for a finite number of switches. The possibility of changing the time interval between these points makes it possible to obtain various modes: a finite mode, in which a given point is reached from any initial state in one switch, and in this mode the switch line is "isochronous"; point sliding mode in which a given point is reached in a finite number of switchings; limit mode, when the length of time intervals tend to zero, and the switching frequency to infinity. Considering this feature the concept of "degree of slip" is introduced. It is shown that in the case of forced movement in the SPS, a sliding motion is observed, which does not allow for ensuring invariance with respect to external disturbances. There are two ways to eliminate the forced component of the movement offered. One of the advantages of using a point sliding mode is that, in order to improve performance, it is not necessary to use a boundary layer, which is realized by entering various logical conditions into the control algorithm. The practical significance of a point sliding mode lies in the fact that, with a small switching frequency, it is possible to maintain the quality indices of an undefined object within an acceptable interval. The studies were conducted for onedimensional second-order linear systems (SISO). Results can be generalized for higher order multidimensional systems. Solution of model problems on MATLAB / Simulink allows us to make a number of positive conclusions that are of great practical importance in terms of expanding the area of use of skipping modes, especially in relation to the management of undefined objects.

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