Elastohydrodynamic Friction Mode as a Method of Surface Finishing Excluding Burnishing

2019 ◽  
Vol 946 ◽  
pp. 732-738
Author(s):  
M.V. Kharchenko ◽  
V.N. Kononov ◽  
E.S. Zambrgitckaya
Keyword(s):  
High Pressures ◽  
Elastohydrodynamic Lubrication ◽  
Surface Finishing ◽  
Elastic Deformations ◽  
Elastic Bodies ◽  
Friction Mode ◽  
Development Processes ◽  
Design Selection ◽  
The Impact ◽  
Lubricant Viscosity

Over the past decades the science of friction has got great development. Processes of friction and wear significantly depend on constructive junction design, selection of wear resistant materials and effective lubricants for them, as well as the conditions of the machinery operation. Currently, a large number of scientific works [7-11, 16-20] are devoted to the review of the contact interaction conditions with the use a lubricant. The method of elastohydrodynamic lubrication is of particular interest when studying different kinds of lubrication. According to the elastohydrodynamic lubrication theory, contact conditions of two elastic bodies are characterized by high pressures which cause the elastic deformation of solids and by the dependence of a lubricant viscosity from the pressure. When using the elastohydrodynamic lubrication the layer profile, the sum amount of elastic deformations, elastic deformations and the lubricant viscosity dependence from pressure are given by set equations [12-15]. The impact of elastohydrodynamic lubrication method on the surface layer of the contacting parts is of great interest.

scholarly journals Effects of non-Newtonian lubricants and elastic coating on transient elastohydrodynamic lubrication at impact squeeze loading

2019 ◽  
Vol 11 (7) ◽  
pp. 168781401986607
Author(s):  
Li-Ming Chu ◽  
Yuh-Ping Chang ◽  
Hsiang-Chen Hsu
Keyword(s):  
Elastohydrodynamic Lubrication ◽  
Flow Index ◽  
Transient Pressure ◽  
Academic Innovation ◽  
Pressure Profiles ◽  
The Impact ◽  
Peak Increase ◽  
Ball Motion ◽  
Lubricant Viscosity ◽  
Peak Value

This study explores the effects of non-Newtonian lubricants on elastohydrodynamic lubrication with coating at impact and rebound loading using power law lubricants. The coupled transient modified Reynolds, rheology, elasticity deformation, and ball motion equations are solved simultaneously, thus obtaining the transient pressure profiles, film shapes, normal squeeze velocities and accelerations. The effect of the flow index ( n) is equivalent to enhancing the lubricant viscosity, also enlarging the damper effect. The simulation results reveal that the film thickness, the primary peak, and the secondary peak increase with increasing the flow index. The greater the flow index is, the earlier the dimple form, and the smaller the maximum value of the impact force is. The rebounding velocity and the peak value of acceleration increase with decreasing the flow index. Moreover, this research possesses academic innovation and industrial application.

scholarly journals Detecting Convergence Trends among EU Universities

Economies ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 42
Author(s):  
Maria Adamakou ◽  
Dimitris Kallioras ◽  
George Petrakos
Keyword(s):  
Methodological Approach ◽  
Basic Research ◽  
Valuable Insight ◽  
Traditional Role ◽  
University Ranking ◽  
Convergence Clubs ◽  
Development Processes ◽  
The Impact ◽  
The Empirical Analysis ◽  
Insight Into

Universities are emerging growth determinants. This is so as, in addition to the fulfillment of their traditional role in teaching and (basic) research, universities, as aptly described within the helix framework, are expected to engage in regional development processes. The paper aims to detect trends of convergence among EU universities in terms of performance. To the best of our knowledge, this topic has not hitherto been examined. The empirical analysis of the paper covers the period 2014–2021, utilizes data obtained from URAP (University Ranking by Academic Performance), and employs the methodological approach of convergence clubs. The findings of the paper provide valuable insight into both theory and policy-making. We conclude that despite the unification of EU educational space, trends of divergence among EU universities are still present, and notable divisions still remain. Consequently, this indicates that the impact of EU universities on the formation of spatial disparities across EU space is not neutral.

scholarly journals Financing of Smart Growth in Less Developed Regions on the Example of Poland

e-Finanse ◽  
2018 ◽  
Vol 14 (3) ◽  
pp. 8-20 ◽  
Author(s):  
Dorota Murzyn
Keyword(s):  
Smart Growth ◽  
Regional Level ◽  
The European Union ◽  
Public Intervention ◽  
Structural Funds ◽  
Factors Influencing ◽  
Development Processes ◽  
Eu Structural Funds ◽  
Research Questions ◽  
The Impact

AbstractThe aim of this paper is twofold. First, the smart growth concept is examined with a focus on challenges associated with applying this concept in the less developed regions. Second, the impact of EU structural funds on smart growth in Poland is analyzed at the regional level with a view to contributing to the debate on public intervention in this area. The research questions are as follows: “Is the concept of smart growth, as postulated by the European Union, well suited to the less developed regions?” and “Whether and to what extent do EU funds contribute to achieving smart growth in Poland?”Smart growth has accelerated after 2007, which could suggest a significant impact of EU structural funds, whose allocation to measures supporting innovative activity rose markedly after 2007. However, among the various factors influencing regional development processes, the impact of structural funds was not as strong as might be expected, which was confirmed by further analysis.

scholarly journals Impact of Different Components and Boundary Conditions on the Eigenfrequencies of a Magnet–Girder Assembly

Instruments ◽  
2021 ◽  
Vol 5 (3) ◽  
pp. 29
Author(s):  
Simone Andresen
Keyword(s):  
Boundary Conditions ◽  
Particle Beam ◽  
Design Development ◽  
Material Density ◽  
Electron Synchrotron ◽  
Support Points ◽  
Beam Stability ◽  
Development Processes ◽  
Large Triangle ◽  
The Impact

Synchrotron radiation facilities are very important in different areas of fundamental and applied science to investigate structures or processes at small scales. Magnet–girder assemblies play a key role for the performance of such accelerator machines. High structural eigenfrequencies of the magnet–girder assemblies are required to assure a sufficient particle beam stability. The objective of the present parametric study was to numerically investigate and quantify the impact of different boundary conditions and components on the magnet–girder eigenfrequencies. As case studies, two 3 m long girder designs following the specifications of the PETRA IV project at DESY (German Electron Synchrotron, Hamburg, Germany) were selected. High magnet–girder assembly eigenfrequencies were achieved by, e.g., positioning the magnets close to the upper girder surface, increasing the connection stiffness between the magnets and the girder and between the girder and the bases, and positioning the girder support points as high as possible in the shape of a large triangle. Comparing the E/ρ ratio (E: Young’s modulus, ρ: material density) of different materials was used as a first approach to evaluate different materials for application to the girder. Based on the findings, general principles are recommended to be considered in the future girder design development processes.

A mixed contact model for an immersed collision between two solid surfaces

2008 ◽  
Vol 366 (1873) ◽  
pp. 2205-2218 ◽  
Author(s):  
Fu-Ling Yang ◽  
Melany L Hunt
Keyword(s):  
Surface Deformation ◽  
Elastohydrodynamic Lubrication ◽  
Solid Particles ◽  
Solid Surfaces ◽  
Additional Energy ◽  
Collision Model ◽  
Dry Granular Flow ◽  
Wide Range ◽  
The Impact ◽  
Surrounding Liquid

Experimental evidence shows that the presence of an ambient liquid can greatly modify the collision process between two solid surfaces. Interactions between the solid surfaces and the surrounding liquid result in energy dissipation at the particle level, which leads to solid–liquid mixture rheology deviating from dry granular flow behaviour. The present work investigates how the surrounding liquid modifies the impact and rebound of solid spheres. Existing collision models use elastohydrodynamic lubrication (EHL) theory to address the surface deformation under the developing lubrication pressure, thereby coupling the motion of the liquid and solid. With EHL theory, idealized smooth particles are made to rebound from a lubrication film. Modified EHL models, however, allow particles to rebound from mutual contacts of surface asperities, assuming negligible liquid effects. In this work, a new contact mechanism, ‘mixed contact’, is formulated, which considers the interplay between the asperities and the interstitial liquid as part of a hybrid rebound scheme. A recovery factor is further proposed to characterize the additional energy loss due to asperity–liquid interactions. The resulting collision model is evaluated through comparisons with experimental data, exhibiting a better performance than the existing models. In addition to the three non-dimensional numbers that result from the EHL analysis—the wet coefficient of restitution, the particle Stokes number and the elasticity parameter—a fourth parameter is introduced to correlate particle impact momentum to the EHL deformation impulse. This generalized collision model covers a wide range of impact conditions and could be employed in numerical codes to simulate the bulk motion of solid particles with non-negligible liquid effects.

The Political Economy of Land and Urban Development

2018 ◽  
pp. 343-359
Author(s):  
Kudzanai Bvochora ◽  
Bernard Kusena
Keyword(s):  
Urban Areas ◽  
Natural Increase ◽  
Rapid Expansion ◽  
The Political ◽  
Social Infrastructure ◽  
The World ◽  
Urban Settlements ◽  
Development Processes ◽  
The Impact ◽  
The Relationship

Many urban areas which have sprouted around the world owe their economic and social origins in growth points and market centers. Situated about 15 kilometers south-east of Harare, Epworth became one of Zimbabwe's largest peri-urban settlements due to the combined effect of demographic, political, and socioeconomic factors, among others. This chapter interrogates the various forces behind this unprecedented population growth. It demonstrates the relationship between Epworth's ballooning population and the various pull and push factors of urbanization. For example, immigration contributed immensely to this rise, although natural increase in births also contributed fairly significantly. This chapter examines the impact of population dynamics and other variables that were linked to the rapid expansion of Epworth on the overall development processes, arguing that economic and social infrastructure became conditioned by such dynamics.

THE IMPACT OF ELASTIC BODIES

1971 ◽  
pp. 266-288
Author(s):  
C. PLUMPTON ◽  
W.A. TOMKYS
Keyword(s):  
Elastic Bodies ◽  
The Impact

The Impact of Regulatory Compliance on Agile Software Processes with a Focus on the FDA Guidelines for Medical Device Software

2011 ◽  
Vol 2 (2) ◽  
pp. 67-81 ◽  
Author(s):  
Hossein Mehrfard ◽  
Abdelwahab Hamou-Lhadj
Keyword(s):  
Medical Device ◽  
Software Process ◽  
Regulatory Compliance ◽  
Extreme Programming ◽  
Organizational Processes ◽  
Medical Device Software ◽  
Development Processes ◽  
Agile Software ◽  
The Impact ◽  
Fda Regulations

The difficulty of complying with different regulations has become more evident as a large number of regulated businesses are mandated to follow an ever-increasing set of regulations. These regulations often drive significant changes in the way organizations operate to deliver value to their customers. This paper focuses on the impact of the Food and Drug Administration (FDA) regulations on agile software development processes, which in many ways can be considered as just another type of organizational processes. Particular focus is placed on the ability for Extreme Programming (XP) to support FDA requirements. Findings show that XP fails to meet many of the FDA guidelines for medical device software, which increases the risks of non-compliance for organizations that have adopted XP as their main software process. The results of this study can lead the work towards designing an extension to XP for FDA regulations.

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