The Effects of Particulate Contamination in Rolling Bearings—a State of the Art Review

1990 ◽  
Vol 204 (1) ◽  
pp. 29-36 ◽  
Author(s):  
R S Sayles ◽  
J C Hamer ◽  
E Ioannides
Keyword(s):  
Surface Defects ◽  
State Of The Art ◽  
Bearing Steel ◽  
Rolling Bearings ◽  
Near Surface ◽  
Particulate Contamination ◽  
Debris Particles ◽  
Rolling Contacts ◽  
The Subject ◽  
Fatigue Failures

The role played by particulate contamination in rolling contacts has formed the subject of much research in recent years. Bearing-steel quality has improved to a level where the long established sub-surface-inclusion based fatigue failures are being replaced by surface or near-surface initiated failures caused by surface defects resulting mainly from rolled-in debris particles. The paper reviews the reasons and mechanisms involved, and shows how particle material, size, concentration and hardness can all have effects on bearing reliability.

Debris and Roughness in Machine Element Contacts: Some Current and Future Engineering Implications

1995 ◽  
Vol 209 (3) ◽  
pp. 149-172 ◽  
Author(s):  
R S Sayles
Keyword(s):  
Local Stress ◽  
Rolling Bearings ◽  
Machine Element ◽  
Debris Particles ◽  
Rolling Contacts ◽  
Lubricant Films ◽  
Potential Contaminant ◽  
The Many ◽  
Constant Velocity Joints ◽  
Practical Implications

The influence of surface roughness and third-body particulates on tribological contacts will be reviewed in general, but in particular their influence on rolling contacts and contacts where rolling and sliding occur simultaneously will be considered in some detail. Such non-conforming contacts are often referred to as Hertzian, and when lubricated are often considered to be protected by an elastohydrodynamic (EHD) lubricant film. Transferring these concepts to the loaded interfaces of real engineering components such as gears, rolling bearings, constant-velocity joints and cams, etc., can have serious shortcomings and lead engineers to many misconceptions. Roughness often appears to dominate over the theoretical size of lubricant films and can create a contact geometry and local stress distribution far removed from the smooth surface case. Even in ball-bearings where surfaces are some of the smoothest of all mass-produced engineering components, lubricant-borne debris particles are usually many times the theoretical film thickness and the damage they can cause can quickly destroy the production engineer's good work in creating smoothness, as well as having a significant influence on component performance. The paper reviews such aspects in terms of recent research and explains some of the many practical implications of roughness and debris that are faced at present, and also speculates on the implications for the future, when roughness geometry and surface properties might be engineered to suit a particular lubricant and its potential contaminant population.

Electron Channelling Contrast Imaging of Dislocations

1990 ◽  
Vol 48 (1) ◽  
pp. 600-601
Author(s):  
J.T. Czernuszka ◽  
N.J. Long ◽  
P.B. Hirsch
Keyword(s):  
Field Emission ◽  
Secondary Electron ◽  
Surface Defects ◽  
Spot Size ◽  
Beam Divergence ◽  
Contrast Imaging ◽  
Scattered Electron ◽  
Near Surface ◽  
Filter System ◽  
Electron Channelling

In the 1970s there was considerable interest in the development of the electron channelling contrast imaging (ECCI) technique for imaging near surface defects in bulk (electron opaque) specimens. The predictions of the theories were realised experimentally by Morin et al., who used a field emission gun (FEG) operating at 40-50kV and an energy filter such that only electrons which had lost no more than a few 100V were detected. This paper presents the results of a set of preliminary experiments which show that an energy filter system is unneccessary to image and characterise the Burgers vectors of dislocations in bulk specimens. The examples in the paper indicatethe general versatility of the technique.A VG HB501 STEM with a FEG was operated at 100kV. A single tilt cartridge was used in the reflection position of the microscope. A retractable back-scattered electron detector was fitted into the secondary electron port and positioned to within a few millimetres of the specimen. The image was acquired using a Synoptics Synergy framestore and digital scan generator and subsequently processed using Semper 6. The beam divergence with the specimen in this position was 2.5 mrads with a spot size of approximately 4nm. Electron channelling patterns were used to orientate the sample.

PLANEJAMENTO FAMILIAR COMO ASSUNTO DE MULHER!? PERFIL DE GÊNERO NA PRODUÇÃO CIENTÍFICA NO BRASIL

2019 ◽  
Vol 8 (1) ◽  
pp. 221-235 ◽  
Author(s):  
Daniella De Paula Chiesa ◽  
Mário Antônio Sanches ◽  
Daiane Priscila Simão-Silva
Keyword(s):  
Family Planning ◽  
Scientific Literature ◽  
State Of The Art ◽  
Health Sciences ◽  
Scientific Production ◽  
The State ◽  
Review Of The Literature ◽  
The Subject

O estudo do Planejamento familiar, no contexto da bioética, abre-se para diversas perspectivas, entre elas a valorização dos seus diferentes atores. Situado neste contexto o artigo tem como objetivo identificar o perfil de gênero na produção científica sobre Planejamento Familiar no Brasil, entre 2000 e 2014, assim como a área de formação e especialização dos autores. Foram utilizadas metodologias que permitiram mapear o estado da arte do tema estudado, a partir de uma revisão da literatura. O resultado da pesquisa identifica que a produção científica sobre Planejamento Familiar no Brasil se compõe de perfil destacadamente feminino (71,76%). Dos 73 artigos analisados, 42 (57,53%) o foco do tema está direcionado à mulher assim como evidencia-se a área de ciências da saúde com maior concentração das publicações do tema.  Este aspecto da pesquisa abre para uma realidade complexa onde se buscam criticamente as razões para a pesquisa em Planejamento Familiar ter ênfase na mulher e ser um tema de relevância nas ciências da saúde.Palavras-chave: Produção científica, Planejamento Familiar, Gênero.  ABSTRACT: The study of Family Planning, in the context of bioethics, opens to diverse perspectives, among them the appreciation of their different agents. Situated in this context the article aims to identify the profile of gender in scientific literature on Family Planning in Brazil, between 2000 and 2014, as well as the area of training and specialization of the authors. Methodologies were used which allowed to map the State of the art of the subject studied, from a review of the literature. The results found identify that the scientific production on Family Planning in Brazil is formed with a outstandingly female profile (71,76%). Of the 73 articles examined, 42 (57.53%) the focus of the topic is directed to women as well as showing the health sciences area with highest concentration of publications. This aspect of the research opens to a complex reality where we seek critically the reasons for Research in Family Planning have emphasis on woman and be a topic of relevance in health sciences.Keywords: Scientific Production, Family Planning, Gender.

A Systematic Literature Review of the EFQM Excellence Model from 1991 to 2019

1970 ◽  
Vol 2 (2) ◽  
pp. 11-15
Author(s):  
Muhammad Yousaf ◽  
Petr Bris
Keyword(s):  
Quality Management ◽  
Data Collection ◽  
Literature Review ◽  
Systematic Literature Review ◽  
Quantitative Research ◽  
Web Of Science ◽  
State Of The Art ◽  
Future Research ◽  
European Foundation ◽  
The Subject

A systematic literature review (SLR) from 1991 to 2019 is carried out about EFQM (European Foundation for Quality Management) excellence model in this paper. The aim of the paper is to present state of the art in quantitative research on the EFQM excellence model that will guide future research lines in this field. The articles were searched with the help of six strings and these six strings were executed in three popular databases i.e. Scopus, Web of Science, and Science Direct. Around 584 peer-reviewed articles examined, which are directly linked with the subject of quantitative research on the EFQM excellence model. About 108 papers were chosen finally, then the purpose, data collection, conclusion, contributions, and type of quantitative of the selected papers are discussed and analyzed briefly in this study. Thus, this study identifies the focus areas of the researchers and knowledge gaps in empirical quantitative literature on the EFQM excellence model. This article also presents the lines of future research.

Direct Plan View FIB Liftout for Near-Surface Defect Analysis in TEM

2013 ◽  
Author(s):  
Max L. Lifson ◽  
Carla M. Chapman ◽  
D. Philip Pokrinchak ◽  
Phyllis J. Campbell ◽  
Greg S. Chrisman ◽  
...  
Keyword(s):  
Failure Analysis ◽  
Silicon Germanium ◽  
Focused Ion Beam ◽  
Surface Defects ◽  
Ion Beam ◽  
Misfit Dislocations ◽  
Tem Analysis ◽  
Plan View ◽  
Near Surface ◽  
Straightforward Method

Abstract Plan view TEM imaging is a powerful technique for failure analysis and semiconductor process characterization. Sample preparation for near-surface defects requires additional care, as the surface of the sample needs to be protected to avoid unintentionally induced damage. This paper demonstrates a straightforward method to create plan view samples in a dual beam focused ion beam (FIB) for TEM studies of near-surface defects, such as misfit dislocations in heteroepitaxial growths. Results show that misfit dislocations are easily imaged in bright-field TEM and STEM for silicon-germanium epitaxial growth. Since FIB tools are ubiquitous in semiconductor failure analysis labs today, the plan view method presented provides a quick to implement, fast, consistent, and straightforward method of generating samples for TEM analysis. While this technique has been optimized for near-surface defects, it can be used with any application requiring plan view TEM analysis.

History of Mathematics in the Islamic World: The Present State of the Art

1985 ◽  
Vol 19 (1) ◽  
pp. 9-33 ◽  
Author(s):  
J. L. Berggren
Keyword(s):  
Present State ◽  
State Of The Art ◽  
History Of Mathematics ◽  
Islamic Culture ◽  
Islamic World ◽  
History Of ◽  
The Subject ◽  
Mathematical Sciences ◽  
Islamic Mathematics

In Recent Years, many discoveries in the history of Islamic mathematics have not been reported outside the specialist literature, even though they raise issues of interest to a larger audience. Thus, our aim in writing this survey is to provide to scholars of Islamic culture an account of the major themes and discoveries of the last decade of research on the history of mathematics in the Islamic world. However, the subject of mathematics comprised much more than what a modern mathematician might think of as belonging to mathematics, so our survey is an overview of what may best be called the “mathematical sciences” in Islam; that is, in addition to such topics as arithmetic, algebra, and geometry we will also be interested in mechanics, optics, and mathematical instruments.

Reemitted positron spectroscopy of near-surface defects

1990 ◽  
Vol 42 (4) ◽  
pp. 1910-1916 ◽  
Author(s):  
T. McMullen ◽  
M. J. Stott
Keyword(s):  
Surface Defects ◽  
Near Surface ◽  
Positron Spectroscopy

More on Brain and Semiosis: Can We Find a Point in Neuronets?

2021 ◽  
pp. 5-13
Author(s):  
Tatiana V. Chernigovskaya ◽  
Keyword(s):  
Language Processing ◽  
Intelligent Systems ◽  
State Of The Art ◽  
Similar Data ◽  
Direct Testing ◽  
The Subject ◽  
Neurophysiological Basis ◽  
Person Experience ◽  
Cognitive Dimensions ◽  
Human Specific

The paper discusses semiotic aspects of higher human functions and a possibility and relevance of traditional search for their neurophysiological basis. The state of the art on the subject is reviewed and the lack of data on anthropological specificity for reasoning, thinking, language and its AI modeling is highlighted. Experimental neuroscience presumes that if we know the characteristics of neu­rons and their connections, we automatically understand what mind and con­sciousness are. However, it is evident that such a paradigm does not allow us to get relevant answers to the main questions. I argue that the problem should be dealt with not only within the field of neurophysiology proper. Rather, such re­search should involve exploring the 'archeology' of mental processes as they are revealed in arts as well as in other symbolic spaces. The paper discusses the ade­quacy of physiological methodology when it is employed to demonstrate brain mechanisms of higher functions. Besides, I explore the relevance of juxta­posing similar data from other biological and artificial intelligent systems. I view language processing, mind and reasoning and 1st person experience (qualia) as human specific features, and questions the possibility of direct testing these phenomena. The paper links genetic, anthropological and neurophysio­logical data to semiotic activity and semiosphere formation as the basis for com­munication. The paper discusses the place of humans in the changing world in the context of new cognitive dimensions.

scholarly journals Environmental issues and international relations, a new global (dis)order - the role of International Relations in promoting a concerted international system

2015 ◽  
Vol 58 (1) ◽  
pp. 191-209 ◽  
Author(s):  
Joana Castro Pereira
Keyword(s):  
International Relations ◽  
Natural Resources ◽  
State Of The Art ◽  
Positive Impact ◽  
International System ◽  
Global Environmental Change ◽  
Environmental Issues ◽  
Global Environmental ◽  
The Subject

Is it possible to talk about the rise of a new global (dis)order founded on the challenges posed by environmental issues? Through the review of the state of the art on the subject, this article analyzes the growing importance of the environment, and natural resources in particular, in international relations; and aims to raise awareness among International Relations scholars to the potential positive impact of the development of the discipline in integration with global environmental change studies.

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