scholarly journals Quality of Dynamics of a Circular Gas-Static Thrust Bearing with an Elastic Suspended Support Center

2019 ◽  
pp. 331-338
Author(s):  
Vladimir A. Kodnyanko ◽  
Andrei S. Kurzakov
Keyword(s):  
Mathematical Model ◽  
Dynamic Characteristics ◽  
Dynamic Systems ◽  
Thrust Bearing ◽  
Calculation Technique ◽  
Degree Of Stability ◽  
Optimal Dynamic ◽  
Bearing Dynamics ◽  
Dynamics Characteristic

A design, a mathematical model are presented and a calculation technique of quality indicators of the gas-static thrust bearing dynamics with the elastic suspended support center is described. It is shown that the application of such improvement allows to eliminate completely essential shortcomings of the quality of dynamics characteristic for a bearing with annular diaphragms and transforms the construction into a dynamic system with optimal dynamic characteristics – high indicators of degree of stability, aperiodic nature of the transient process, values of the oscillation index that are peculiar to ideally damped dynamic systems

Multifactor mathematical model of criticality of welding process of products from aluminum- magnesium alloys

2020 ◽  
pp. 12-18
Author(s):  
F.A. Urazbahtin ◽  
A.YU. Urazbahtina
Keyword(s):  
Mathematical Model ◽  
Magnesium Alloy ◽  
Magnesium Alloys ◽  
Welding Process ◽  
Welding Equipment ◽  
Equipment Operation ◽  
Aluminum Magnesium Alloys ◽  
Aluminum Magnesium Alloy ◽  
Welding Materials

A multifactor mathematical model of the welding process of products from aluminum-magnesium alloys, consisting of 71 indicators that assess the quality of the weld, the welding process, costs, equipment operation and quality of the welded material. The model can be used to control and optimize the welding process of products from aluminum-magnesium alloys. Keywords welding, products, aluminum-magnesium alloy, indicators, process parameters, welding equipment, welding materials, electrode sharpening, lining [email protected]

Network analysis models – the secret for success

2004 ◽  
Vol 4 (5-6) ◽  
pp. 383-388
Author(s):  
D.M. Rogers
Keyword(s):  
Mathematical Model ◽  
Field Data ◽  
Essential Element ◽  
Distribution Networks ◽  
Automatic Calibration ◽  
Supply And Distribution ◽  
The World ◽  
Optimum Approach ◽  
Analysis Models

Water is a fundamental necessity of life. Yet water supply and distribution networks the world over are old and lacking in adequate maintenance. Consequently they often leak as much water as they deliver and provide an unacceptable quality of service to the customer. In certain parts of the world, water is available only for a few hours of the day. The solution is to build a mathematical model to simulate the operation of the real network in all of its key elements and apply it to optimise its operation. To be of value, the results of the model must be compared with field data. This process is known as calibration and is an essential element in the construction of an accurate model. This paper outlines the optimum approach to building and calibrating a mathematical model and how it can be applied to automatic calibration systems.

Numerical Simulation on Mold Electromagnetic Eccentric Stirring and Central Segregation of Round Bloom

2013 ◽  
Vol 652-654 ◽  
pp. 2450-2454
Author(s):  
Zhi Hong Zhang ◽  
Guo Guang Cheng
Keyword(s):  
Numerical Simulation ◽  
Mathematical Model ◽  
Electromagnetic Stirring ◽  
Center Line ◽  
Central Segregation

The paper describes multi-section round bloom casting using external MEMS, equipped with max section D600mm and min D280mm mold, the center line of D280mm mold not coincident with the axis of stirrer coils. it is exist eccentric electromagnetic stirring of mold which section less than max D600mm, a mathematical model of MEMS has been established, the index of central segregation of D280mm macrostructure had decreased less than 1.12 by optimized parameters of electromagnetic stirring and SEN immerse depth, in the end, the quality of round bloom had improved.

scholarly journals Dynamic Quality of an Aerostatic Thrust Bearing with a Microgroove and Support Center on Elastic Suspension

Mathematics ◽  
2021 ◽  
Vol 9 (13) ◽  
pp. 1492
Author(s):  
Vladimir Kodnyanko ◽  
Stanislav Shatokhin ◽  
Andrey Kurzakov ◽  
Lilia Strok ◽  
Yuri Pikalov ◽  
...  
Keyword(s):  
Dynamic Characteristics ◽  
Negative Impact ◽  
Aerostatic Bearing ◽  
Elastic Suspension ◽  
Variable Parameters ◽  
Aerostatic Bearings ◽  
Improved Design ◽  
Dynamic Quality ◽  
Bearing Layer

The disadvantage of aerostatic bearings is their low dynamic quality. The negative impact on the dynamic characteristics of the bearing is exerted by the volume of air contained in the bearing gap, pockets, and microgrooves located at the outlet of the feeding diaphragms. Reducing the volume of air in the flow path is a resource for increasing the dynamic quality of the aerostatic bearing. This article presents an improved design of an axial aerostatic bearing with simple diaphragms, an annular microgroove, and an elastic suspension of the movable center of the supporting disk. A mathematical model is presented and a methodology for calculating the static characteristics of a bearing and dynamic quality indicators is described. The calculations were carried out using dimensionless quantities, which made it possible to reduce the number of variable parameters. A new method for solving linearized and Laplace-transformed boundary value problems for transformants of air pressure dynamic functions in the bearing layer was applied, which made it possible to obtain a numerical solution of problems sufficient for practice accuracy. The optimization of the criteria for the dynamic quality of the bearing was carried out. It is shown that the use of an elastic suspension of the support center improves its dynamic characteristics by reducing the volume of compressed air in the bearing layer and choosing the optimal volume of the microgroove.

The Numerical Analysis of the Velocity and Pressure Distribution of the Oil Film in Heavy Hydrostatic Thrust Bearing

2014 ◽  
Vol 541-542 ◽  
pp. 658-662
Author(s):  
Jian Li ◽  
Yuan Chen ◽  
Yang Chun Yu ◽  
Zhu Xin Tian ◽  
Yu Huang
Keyword(s):  
Mathematical Model ◽  
Numerical Analysis ◽  
Pressure Distribution ◽  
Working Conditions ◽  
Thrust Bearing ◽  
Rotation Speed ◽  
The Other ◽  
Surface Load ◽  
Oil Film ◽  
Volume Method

To study the velocity and pressure distribution of the oil film in a heavy hydrostatic thrust bearing, a mathematical model of the velocity is proposed and the finite volume method (FVM) has been used to simulate the flow field under different working conditions. Some pressure experiments were carried out and the results verified the correctness of the simulation. It is concluded that the pressure distribution varies small under different rotation speed when the surface load on the workbench is constant. But the velocity of the oil film is influenced greatly by the rotation speed. When the rotation speed of the workbench is as quick as enough, the velocity of the oil film on one radial side of the pad will be zero, that is to say the lubrication oil will be drained from the other three sides of the recess.

scholarly journals Determination of the Vertical Load on the Carrying Structure of a Flat Wagon with the 18–100 and Y25 Bogies

2021 ◽  
Vol 11 (9) ◽  
pp. 4130
Author(s):  
Oleksij Fomin ◽  
Alyona Lovska ◽  
Václav Píštěk ◽  
Pavel Kučera
Keyword(s):  
Mathematical Model ◽  
Fatigue Strength ◽  
Service Life ◽  
Dynamic Characteristics ◽  
Dynamic Load ◽  
Field Tests ◽  
Vertical Load ◽  
Mathcad Software ◽  
The Mathematical Model

The study deals with determination of the vertical load on the carrying structure of a flat wagon on the 18–100 and Y25 bogies using mathematic modelling. The study was made for an empty wagon passing over a joint irregularity. The authors calculated the carrying structure of a flat wagon with the designed parameters and the actual features recorded during field tests. The mathematical model was solved in MathCad software. The study found that application of the Y25 bogie for a flat wagon with the designed parameters can decrease the dynamic load by 41.1% in comparison to that with the 18–100 bogie. Therefore, application of the Y25 bogie under a flat wagon with the actual parameters allows decreasing the dynamic loading by 41.4% in comparison to that with the 18–100 bogie. The study also looks at the service life of the supporting structure of a flat wagon with the Y25 bogie, which can be more than twice as long as the 18–100 bogie. The research can be of interest for specialists concerned with improvements in the dynamic characteristics and the fatigue strength of freight cars, safe rail operation, freight security, and the results of the research can be used for development of innovative wagon structures.

The Relationship Between Government Popularity and Approval for the Government's Record in the United Kingdom

1985 ◽  
Vol 15 (2) ◽  
pp. 165-186 ◽  
Author(s):  
John Hudson
Keyword(s):  
The Public ◽  
The Past ◽  
The United Kingdom ◽  
State Of The Economy ◽  
Degree Of Stability ◽  
Key Variables ◽  
The Government ◽  
The Relationship ◽  
Opinion Polls

The past decade has seen the growth of a considerable literature on the link between government popularity, as reflected by the proportion of the public indicating their intention to vote for the government in opinion polls, and the state of the economy, as represented by certain key variables. The work began in the early 1970s with articles by Goodhart and Bhansali, Mueller, and Kramer. It continued through the decade; some of the more recent contributions can be found in a set of readings edited by Hibbs and Fassbender. However, despite the amount and quality of this work, problems remain. Principal amongst these, as Chrystal and Alt have pointed out, is the inability to estimate a relationship which exhibits any degree of stability either over time or between researchers. Nearly all the studies have been successful in finding a significant relationship for specific time periods, but when these are extended, or when the function is used to forecast outside the original estimation period, the relationship appears to break down.

scholarly journals INCREASING THE COMPETITIVENESS OF INSURANCE COMPANY PRODUCTS AND SERVICES USING ECONOMIC AND MATHEMATICAL MODELING METHODS

2021 ◽  
Author(s):  
Mykhailo Demydenko ◽  
Ihor Pistunov
Keyword(s):  
Mathematical Model ◽  
Social Activity ◽  
Insurance Companies ◽  
Comprehensive System ◽  
Insurance Company ◽  
Competitive Advantages ◽  
Insurance Policy ◽  
Insurance Policies ◽  
The Impact

The competitiveness of an insurance company depends on the competitiveness of the products and services it introduces in the market. The competitive advantages of the insurance company are expressed in the attractiveness and competitiveness of insurance policies. An economic and mathematical model of increasing the competitiveness of the insurance company is proposed, which allows to calculate the integrated indicator of competitiveness of the insurance policy based on a comprehensive system of indicators characterizing the reliability of the insurance company, quality of its services, competitiveness, social activity. To analyze the impact of these indicators on the competitiveness of the insurance policy and identify areas for improving the efficiency and competitiveness of the insurance company. The competitiveness of an insurance company depends on the competitiveness of the products and services it introduces in the market. The assessment of the quality of insurance company services is compliance with the needs, requirements, and insurance interests of customers. This assessment is performed each time an individual client chooses to cooperate with an insurance company that meets his insurance interests and wishes. Therefore, the overall competitiveness of the enterprise depends on the competitiveness of products and services offered on the market. The competitive advantages of the insurance company are expressed in the attractiveness and competitiveness of insurance policies. The insurance market in recent years has shown consistently high growth, which makes it attractive for doing business. In these conditions, the task of modeling the activities of the insurance company in a highly competitive market environment becomes relevant. A mathematical model of increasing the competitiveness of the insurance company is proposed, which allows to calculate the integrated indicator of competitiveness of the insurance policy based on a comprehensive system of indicators characterizing the reliability of the insurance company, quality of its services, competitiveness, social activity. With the proposed model, insurance companies can objectively assess their weaknesses and strengths to ensure continuous growth and decent competition in a competitive market environment. The model allows you to select performance indicators and perform modeling and determine the consequences of changes in this indicator, analyze the impact of these indicators on the competitiveness of insurance policies and identify areas for improving the efficiency and competitiveness of the insurance company. By conducting such experiments, insurance companies can make more informed choices and decisions, analyze areas of competitiveness, and more efficiently allocate resources.

scholarly journals Researches on Rheological Characteristics of Dough of Wheat Flour and their Changes During Storage

2011 ◽  
Vol 68 (2) ◽  
Author(s):  
Gheorghe CONSTANTIN ◽  
Gheorghe VOICU ◽  
Carmen Otilia RUSĂNESCU ◽  
Elena Mădălina ŞTEFAN
Keyword(s):  
Absorption Capacity ◽  
Rheological Characteristics ◽  
Gluten Strength ◽  
Structure Changes ◽  
Degree Of Stability ◽  
Laboratory Device ◽  
Brabender Farinograph ◽  
Changes Over Time ◽  
Dough Development Time

In this paper, rheological characteristics of flour are determined with Brabender farinograph. Brabender Farinograph is the most widely used laboratory device to evaluate the quality of flour, in batter, with which the rheological characteristics of flour is determined by measuring and recording gluten strength and endurance. With farinograph records the dough structure changes over time and obtaining data about: Absorption of flour, flour power (its ability to form a dough with rheological properties appropriate to flow operations technology), forming time of the dough, the degree of stability and soaking, the consistency of dough during this time. Analyzing the data presented on farinograph curves, were extracted the values of the dough development time (min), stability (min), softening degree (FU), consistency (FU), the absorption capacity of flour (%) farinograph index of the dough ..

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