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.

scholarly journals Theoretical Efficiency Study of Output Lubricant Flow Rate Regulating Principle on the Example of a Two-Row Aerostatic Journal Bearing with Longitudinal Microgrooves and a System of External Combined Throttling

Mathematics ◽  
2021 ◽  
Vol 9 (14) ◽  
pp. 1698
Author(s):  
Vladimir Kodnyanko ◽  
Stanislav Shatokhin ◽  
Andrey Kurzakov ◽  
Yuri Pikalov ◽  
Lilia Strok ◽  
...  
Keyword(s):  
Flow Rate ◽  
Dynamic Characteristics ◽  
Machine Tools ◽  
Theoretical Study ◽  
Load Capacity ◽  
Finite Difference Methods ◽  
Output Flow ◽  
Aerostatic Bearings ◽  
Dynamic Quality ◽  
Active Flow

Due to their vanishingly low air friction, high wear resistance, and environmental friendliness, aerostatic bearings are used in machines, machine tools, and devices that require high accuracy of micro-movement and positioning. The characteristic disadvantages of aerostatic bearings are low load capacity, high compliance and an increased tendency for instability. In radial bearings, it is possible to use longitudinal microgrooves, which practically exclude circumferential air leakage, and contributes to a significant increase in load-bearing capacity. To reduce compliance to zero and negative values, inlet diaphragm and elastic airflow regulators are used. Active flow compensation is inextricably linked to the problem of ensuring the stability of bearings due to the presence of relatively large volumes of gas in the regulator, which have a destabilizing effect. This problem was solved by using an external combined throttling system. Bearings with input flow regulators have a number of disadvantages-they are very energy-intensive and have an insufficiently stable load capacity. A more promising way to reduce compliance is the use of displacement compensators for the movable element. Such bearings also allow for a decrease in compliance to zero and negative values, which makes it possible to use them not only as supports, but also as active deformation compensators of the technological system of machine tools in order to reduce the time and increase the accuracy of metalworking. The new idea of using active flow compensators is to regulate the flow rate not at the inlet, but at the outlet of the air flow. This design has the energy efficiency that is inherent to a conventional bearing, but the regulation of the lubricant output flow allows the compliance to be reduced to zero and negative values. This article discusses the results of a theoretical study of the static and dynamic characteristics of a two-row radial aerostatic bearing with longitudinal microgrooves and an output flow regulator. Mathematical modeling and theoretical study of stationary modes have been carried out. Formulas for determining static compliance and load capacity are obtained. Iterative finite-difference methods for determining the dynamic characteristics of a structure are proposed. The calculation of dynamic quality criteria was carried out on the basis of the method of rational interpolation of the bearing transfer function, as a system with distributed parameters, developed by the authors. It was found that the volumes of the microgrooves do not have a noticeable effect on the bearing dynamics. It is shown that, in this design, the external combined throttling system is an effective means of maintaining stability and high dynamic quality of the design operating in the modes of low, zero and negative compliance.

scholarly journals Theoretical Investigation on Performance Characteristics of Aerostatic Journal Bearings with Active Displacement Compensator

2021 ◽  
Vol 11 (6) ◽  
pp. 2623
Author(s):  
Vladimir Kodnyanko ◽  
Stanislav Shatokhin ◽  
Andrey Kurzakov ◽  
Yuri Pikalov ◽  
Maxim Brungardt ◽  
...  
Keyword(s):  
Air Flow ◽  
Stability Margin ◽  
Quality Criteria ◽  
Dynamic Compliance ◽  
Theoretical Research ◽  
Elastic Displacement ◽  
Nonlinear Boundary Value Problems ◽  
Elastic Suspension ◽  
Aerostatic Bearings ◽  
Dynamic Quality

Active aerostatic bearings are capable of providing negative compliance, which can be successfully used to automatically compensate for deformation of the machine tool system in order to reduce the time and improve the quality of metalworking. The article considers an aerostatic radial bearing with external combined throttling systems and an elastic displacement compensator, which is an alternative to aerostatic bearings with air flow rate compensators. The results of the mathematical modeling and theoretical research of stationary and nonstationary modes of operation of bearings with slotted and diaphragm throttling systems are presented. A counter-matrix sweep method has been developed for solving linear and nonlinear boundary value problems in partial derivatives with respect to the function of the square of the pressure in the bearing gap and inter-throttling bearing cavities for any values of the relative shaft eccentricity. A numerical method is proposed for calculating the dynamic quality criteria, and the transfer function of the dynamic compliance of a bearing with small displacements is considered as a linear automatic control system with distributed parameters. An experimental verification of the theoretical characteristics of the bearing was carried out, which showed a satisfactory correspondence among the compared data. It is shown that bearings with a throttle system have the best quantitative and qualitative load characteristics. The possibility of optimal determination of the values of a number of important parameters that provide the bearing with optimal performance and a high stability margin is established. It is shown that bearings with an elastic suspension of the movable sleeve allow one to compensate for significant movements, which can be larger than the size of the air gap by an order of magnitude or more. In these conditions, similar bearings with air flow compensators would be obviously inoperative.

Assessment of the quality of opening of soil structures technical means developed in Kuban State Agrarian University

2020 ◽  
Author(s):  
B. F. Tarasenko B. F. ◽  
◽  
S. Y. Orlenko S. Y. ◽  
V. V. Kuzmin V. V.
Keyword(s):  
Comparative Analysis ◽  
Field Tests ◽  
Soil Structures ◽  
Improved Design

The article presents a comparative analysis, based on field tests, of the quality of loosening of soil structures of the upper horizon with technical means developed at KubSAU and an improved design of a universal tillage unit.

Green Beans Cultivation Using Mice Pets Control to Improve the Quality of Bintaro Fruit Extract

2018 ◽  
Vol 1 (1) ◽  
pp. 38
Author(s):  
Ajeng Embri Legawati ◽  
Nur Azizah ◽  
Achmad Ramadhan
Keyword(s):  
Natural Resources ◽  
Negative Impact ◽  
Green Beans ◽  
Fruit Extract ◽  
Bean Plants ◽  
Cultivation Technology ◽  
Environmental Balance ◽  
The Impact ◽  
Chemical Pesticides

Green beans cultivation technology using mice pets control has been implemented in the Gluranploso village, Benjeng Gresik. The implementation of the technology performed for 2.5 months from August to October 2017. The purpose of the implementation is aimed to reduce the dependence of farmers on the use of chemical pesticides so that the farmers are aware of the negative impact of chemical pesticides. Assessing the impact of the utilization of Bintaro fruit and fruit extracts to explore ways of making Bintaro as a natural biopesticide to overcome rat attack on green bean plants in the Gluranploso village. Pest control mice can reduce the rate of loss of the crops more effectively and efficiently. Finally, with the use of those natural resources as a biopesticide material can also maintain the environmental balance

CHRONOBIOLOGICAL AND PSYCHOEMOTIONAL STATUS IN WOMEN WITH CHRONIC RECURRENT BACTERIAL CYSTITIS AND CARBOHYDRATE METABOLISM DISORDER

2020 ◽  
pp. 56-59
Author(s):  
Мария Николаевна Химичева ◽  
Андрей Владимирович Кузьменко ◽  
Владимир Васильевич Кузьменко ◽  
Тимур Асланбекович Гяургиев
Keyword(s):  
Chronic Disease ◽  
Carbohydrate Metabolism ◽  
Negative Impact ◽  
High Risk Group ◽  
Chronic Complications ◽  
Course Of Disease ◽  
Metabolism Disorder ◽  
Common Group ◽  
Tract Infections

Инфекции мочевых путей - наиболее распространённая группа заболеваний в практике врача уролога. Один из представителей является хронический рецидивирующий бактериальный цистит. Данное заболевание встречается во всех возрастных категориях и затрагивает все сферы жизни пациентов. Симптомы, возникающие при обострении хронического бактериального цистита, оказывают негативное влияние на качество жизни, что может приводить к нарушению психоэмоционального состояния больных. Отдельную группу высокого риска в отношении ИНМП составляют пациенты с нарушением углеводного обмена, у которых риск развития различных инфекций выше, чем у людей без подобных нарушений. К факторам, повышающим риск развития ИНМП у больных с нарушением углеводного обмена, относят возраст, компенсацию и наличие хронических осложнений, в первую очередь нефропатии и цистопатии. Человеческий организм функционирует циклически в соответствии с определенными индивидуальными ритмами. Любое хроническое заболевание приводит к рассогласованию процессов, протекающих в различных системах организма, вызывая развитие десинхроноза. Наличие у человека более 1 хронического заболевания утяжеляет течение болезни и приводит к снижению восстановительных способностей организма и сокращению его адаптационного потенциала Urinary tract Infections are the most common group of diseases in the practice of a urologist. One of the representatives is chronic recurrent bacterial cystitis. This disease occurs in all age categories and affects all areas of life of patients. Symptoms that occur with the exacerbation of chronic bacterial cystitis have a negative impact on the quality of life, which can lead to a violation of the psychoemotional state of patients. A separate high-risk group for INMP is patients with impaired carbohydrate metabolism, who have a higher risk of developing various infections than people without such disorders. Factors that increase the risk of developing INMP in patients with impaired carbohydrate metabolism include age, compensation, and the presence of chronic complications, primarily nephropathy and cystopathy. The human body functions cyclically in accordance with certain individual rhythms. Any chronic disease leads to misalignment of the processes occurring in various body systems, causing the development of DS, the Presence of more than 1 chronic disease complicates the course of disease and leads to a decrease in regenerative abilities of the organism and reduce its adaptive capacity

Modern challenges of border areas development in the context of decentralization reform

2019 ◽  
pp. 79-89
Author(s):  
Khrystyna Prytula ◽  
Yaroslava Kalat ◽  
Iryna Kyryk
Keyword(s):  
Ethnic Minorities ◽  
Negative Impact ◽  
Local Development ◽  
Economic Security ◽  
Uneven Development ◽  
Scientific Article ◽  
Border Regions ◽  
Border Areas ◽  
Decentralization Reform

An integral part of the implementation of any reform is the emergence of the risks of its negative impact on one or another area of region development. The decentralization reform in Ukraine is not an exception. In its the context the most probable occurrence of negative phenomena is in the border regions, which could be prevented by first detecting them. In the scientific article, the authors focus on the analysis of a number of challenges for the development of border regions in the context of decentralization reform. Given the territorial remoteness of the central regions of the country and the capital, which today serve as areas of concentration of investment and economic activity, the border regions traditionally (this is typical for the border areas of the EU member states) lag behind the rest of the regions by the main socio-economic indicators of development. Among the main challenges facing the border regions of Ukraine today are the following: the provision of competitiveness in the context of European integration processes and reduction of the border barrier function; low level of economic security; the outflow of human capital and the issue of ethnic minorities. Based on an expert survey of representatives of the fifteen united territorial communities (UTCs), the possibility of such risks of decentralization in the border regions were defined as following: groundless use of local budget funds; emergence of significant imbalances between delegated new authority and available financial resources of the community; increasing uneven development of territories within the community; increasing uneven development of communities within the country; deterioration of the availability and quality of providing educational and medical services; deterioration of the quality of local government; reducing of the state influence on the management of local development processes; radicalization of political unions representing the interests of ethnic minorities in places of their compact residence; further economic decline of the territory of communities and so on.

Coleridge and Contemplation

2017 ◽  
Keyword(s):  
Historical Background ◽  
New Developments ◽  
English Departments ◽  
Original Essays ◽  
Wide Range ◽  
Romantic Era ◽  
Renaissance Man ◽  
Dynamic Quality ◽  
Philosophical Writings

In his philosophical writings, Coleridge increasingly developed his thinking about imagination, a symbolizing precursor to contemplation, to a theory of contemplation itself, which for him occurs in its purest form as a manifestation of ‘Reason’. Coleridge is a particularly challenging figure because he was a thinker in process, and something of an omnimath, a Renaissance man of the Romantic era. The dynamic quality of his thinking, the ‘dark fluxion’ pursued but ultimately ‘unfixable by thought’, and his extensive range of interests make essential an approach that is philosophical yet also multi-disciplinary. This is the first collection of essays to be written mainly by philosophers and intellectual historians on a wide range of Coleridge’s philosophical writings. With a foreword by Baroness Mary Warnock, and original essays on Coleridge and Contemplation by prominent philosophers such as Sir Roger Scruton, David E. Cooper, Michael McGhee, and Andy Hamilton, this volume provides a stimulating collection of insights and explorations into what Britain’s foremost philosopher-poet had to say about the contemplation that he considered to be the highest of the human mental powers. The essays by philosophers are supported by new developments in philosophically minded criticism from Coleridge scholars in English departments, including Jim Mays, Kathleen Wheeler, and James Engell. They approach Coleridge as an energetic yet contemplative thinker concerned with the intuition of ideas and the processes of cultivation in self and society. Other essays, from intellectual historians and theologians, clarify the historical background, and ‘religious musings’, of Coleridge’s thought regarding contemplation.

Perianal Hyperhidrosis Successfully Treated with Botulinum Toxin A

2021 ◽  
pp. 1-4
Author(s):  
Leandra Reguero del Cura ◽  
Marta Drake Monfort ◽  
Adrian De Quintana Sancho ◽  
Marcos Antonio González López
Keyword(s):  
Botulinum Toxin ◽  
Negative Impact ◽  
Botulinum Toxin A ◽  
Psychosocial Burden ◽  
Toxin A ◽  
Rare Form ◽  
Good Safety Profile ◽  
Degree Of Satisfaction ◽  
Botulinum Toxin Injections

Perianal hyperhidrosis (HH) is a rare form of primary focal HH and may become a major problem for the patient with a significant psychosocial burden and negative impact on the quality of life. Botulinum toxin injections are widely used as a second-line treatment option for axillary, palmar, and plantar HH with a good safety profile. Herein, we pre­sent a case of primary perianal HH successfully treated with Botulinum toxin A at a dose higher than that previously reported in literature, with a longer response, a higher degree of satisfaction, and no adverse effects. Moreover, we review the main aspects of the perianal anatomy that are essential to carry out the technique correctly and make dermatologists achieve expertise with the procedure.

scholarly journals New diagonal micropolarizer arrays designed by an improved model in fourier domain

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jia Hao ◽  
Yan Wang ◽  
Kui Zhou ◽  
Xiaochang Yu ◽  
Yiting Yu
Keyword(s):  
Stokes Parameters ◽  
Fourier Domain ◽  
Extended Model ◽  
Reconstruction Accuracy ◽  
Polarization Imaging ◽  
New Class ◽  
Reconstruction Quality ◽  
Improved Design ◽  
Improved Model

AbstractThe design of micropolarizer array (MPA) patterns in Fourier domain provides an efficient approach to reconstruct and investigate the polarization information. Inspired by Alenin’s works, in this paper, we propose an improved design model to cover both 2 × N MPAs and other original MPAs, by which an entirely new class of MPA patterns is suggested. The performance of the new patterns is evaluated through Fourier domain analysis and numerical simulations compared with the existing MPAs. Particularly, we analyze the reconstruction accuracy of the first three Stokes parameters and degree of linear polarization (DoLP) in detail. The experimental results confirm that the 2 × 2 × 2 MPA provides the highest reconstruction quality of s0, s1, s2 and DoLP in terms of quantitative measures and visual quality, while the 3 × 3 diagonal MPA achieves the state-of-the-art best results in case of single-snapshot systems. The guidance of this extended model and new diagonal MPAs show its massive potential for the division of focal plane (DoFP) polarization imaging applications.

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