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.

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.

The many faces of suzhi in the Chinese organization and society

2014 ◽  
Vol 5 (1) ◽  
pp. 51-61 ◽  
Author(s):  
Sean Upton-McLaughlin
Keyword(s):  
Chinese Culture ◽  
Mainland China ◽  
Future Research ◽  
Chinese Society ◽  
Content Type ◽  
Mainland Chinese ◽  
Foreign Companies ◽  
Expatriate Managers ◽  
The Many ◽  
Practical Implications

Purpose – The purpose of this paper was to explore the Chinese concept of suzhi and how it relates to behavioral standards within mainland Chinese society and the workplace. The article provides a general discussion of suzhi and its inherent elements to act as a foundation for the education of expatriate managers and executives and for future research by Chinese human resource management (HRM) scholars. Design/methodology/approach – This paper draws on the author's first-hand experience and observations from five years of living and working abroad in mainland China with Chinese companies and executives. Findings – The concept of suzhi in China is a reflection of multiple behavioral standards throughout China. And while suzhi's roots are in ancient Chinese culture and Confucianism, it is also subject to influence and change. Practical implications – The paper may serve as a foundation both for expatriate managers seeking to improve HRM practices in foreign companies in China and future scholars who wish to conduct further research on suzhi and Chinese behavioral standards as they can be applied to the workplace. Originality/value – This is an attempt to enlighten expatriate managers and executives in China on the concept of suzhi and its implication for HRM in China.

scholarly journals Approaches to help the practitioner determine “are we a learning organization”

2018 ◽  
Vol 25 (5) ◽  
pp. 362-365
Author(s):  
Simon Reese
Keyword(s):  
Learning Organization ◽  
Design Methodology ◽  
Content Type ◽  
The Many ◽  
Practical Implications

Purpose The “Implication for practitioners” paper summarizes the articles within this issue of The Learning Organization in an easy-to-digest format for the practitioner audience. This paper aims to outline how in practice the structure and people and the interplay of both have an impact in creating a learning organization. Included in the paper is a summary of articles within this issue that outline different studies that can easily lead toward actions in practice. Design/methodology/approach The summary identifies specific elements from the articles within this issue that can applied in practice. Findings This issue of The Learning Organization is full of content to help practitioners think more deeply about assessing their organization and offers application of tools that can be easily applied in any organization. Practical implications The “Implication for practitioners” paper aims to outline areas where the articles can be further applied. The articles within this issue outline how structure and characteristics (or people) can provide a significant impact on developing a learning organization. Originality/value Readers can gain value in reading this summary, as it outline some of the many practical ideas outlined within the articles of this issue of The Learning Organization.

Developing a domain ontology for knowledge management technologies

2018 ◽  
Vol 42 (1) ◽  
pp. 28-44 ◽  
Author(s):  
Parvin Hashemi ◽  
Ameneh Khadivar ◽  
Mehdi Shamizanjani
Keyword(s):  
Knowledge Management ◽  
Formal Ontology ◽  
Content Type ◽  
Web Environment ◽  
Km Strategy ◽  
The Many ◽  
Common Understanding ◽  
Taxonomic Relations ◽  
Practical Implications

Purpose The purpose of this paper is to develop a new ontology for knowledge management (KM) technologies, determining the relationships between these technologies and classification of them. Design/methodology/approach The study applies NOY methodology – named after Natalya F. Noy who initiated this methodology. Protégé software and ontology web language are used for building the ontology. The presented ontology is evaluated with abbreviation and consistency criteria and knowledge retrieval of KM technologies by experts. Findings All the main concepts in the scope of KM technologies are extracted from existing literature. There are 241 words, 49 out of them are domain concepts, eight terms are about taxonomic and non-taxonomic relations, one term relates to data property and 183 terms are instances. These terms are used to develop KM technologies’ ontology based on three factors: facilitating KM processes, supporting KM strategies and the position of technology in the KM technology stage model. The presented ontology is created a common understanding in the field of KM technologies. Research limitations/implications Lack of specific documentary about logic behind decision making and prioritizing criteria in choosing KM technologies. Practical implications Uploading the presented ontology in the web environment provides a platform for knowledge sharing between experts from around the world. In addition, it helps to decide on the choice of KM technologies based on KM processes and KM strategy. Originality/value Among the many categories of KM technologies in literature, there is no classifying according to several criteria simultaneously. This paper contributes to filling this gap and considers KM processes, KM strategy and stages of growth for KM technologies simultaneously to choice the KM technologies and also there exists no formal ontology regarding KM technologies. This study has tried to propose a formal KM technologies’ ontology.

Implementation of ISO-22000 in Spain: obstacles and key benefits

2014 ◽  
Vol 116 (10) ◽  
pp. 1581-1599 ◽  
Author(s):  
Carmen Escanciano ◽  
María Leticia Santos-Vijande
Keyword(s):  
Factor Analysis ◽  
Food Industry ◽  
Design Methodology ◽  
Implementation Process ◽  
Adoption Process ◽  
Content Type ◽  
The Status ◽  
The Many ◽  
Implementation Data ◽  
Practical Implications

Purpose – The purpose of this paper is to analyze the status of the implementation of ISO 22000 in the food industry in Spain. The study identifies the main difficulties faced by firms during the adoption process, the benefits obtained, and the most influential benefits on firms overall satisfaction with ISO 22000. Design/methodology/approach – A questionnaire was developed to identify the difficulties and benefits for ISO 22000 implementation. Data were collected among 189 Spanish certified firms. Factor analysis and multiple linear regression were used. Findings – ISO 22000 is used by firms operating in all links of the food chain (FC). Size of the firm is not a factor that determines its implementation. Exporter firms are more attracted to ISO 22000 certification. All sample firms experienced difficulties throughout the implementation process, being those related with time and money the most relevant. The benefits which most contributed to the firms’ satisfaction were internal in nature, in particular, those related to improved efficiency and food safety. Practical implications – Despite the many difficulties, both material and organizational, that sample firms experienced in implementing ISO 22000, and the complexity of the standard, the overall satisfaction is high. Originality/value – The sample analyzed comprised certified firms, including representatives of all links in the FC from farm to table. Prior research specifically aimed at analyzing ISO 22000 implementation and its benefits is very scarce.

scholarly journals From fragile to agile: marketing as a key driver of entrepreneurial internationalization

2019 ◽  
Vol 36 (2) ◽  
pp. 260-288 ◽  
Author(s):  
Birgit Hagen ◽  
Antonella Zucchella ◽  
Pervez Nasim Ghauri
Keyword(s):  
Business Processes ◽  
Functional Dependencies ◽  
Multiple Stakeholders ◽  
Content Type ◽  
Partner Interaction ◽  
Key Driver ◽  
Strategic Agility ◽  
The Many ◽  
Practical Implications

PurposeThe purpose of this paper is to conceptualize strategic agility in entrepreneurial internationalization and highlight the role of marketing “under particular conditions” – those of early and fast internationalizers.Design/methodology/approachThe study is based on in-depth case studies of four entrepreneurial internationalizers using an inductive approach. The role of marketing is studied along a set of four key business processes, i.e. sensing through selective customer/partner intimacy; business development through selective experimentation and testing; coordination and harmonization of multiple stakeholders; and creative extension of resources.FindingsStrategic agility is a composite of flexibility and selective responsiveness. Marketing thought, mainly through customer and partner interaction, plays a prominent role in achieving strategic agility. Customer- and market-centric thinking needs to be built in a key set of business processes. Marketing’s contribution to strategic agility means an ability to cope with time, relationship and functional dependencies. Strategic agility helps improve the risk profile of the entrepreneurial internationalizer. Entrepreneurial internationalizers are particularly suited to compete on and benefit from strategic agility.Practical implicationsThe findings show managers and entrepreneurs in early and fast internationalizing ventures a path to strategic agility which helps to overcome the many parallel challenges that come with firm foundation and internationalization.Originality/valueStrategic agility is a novel explanation for entrepreneurial internationalization. The study explains the prominent role played by marketing in achieving strategic agility and growth. Strategic agility is reconceptualized in the context of the young and small internationalizing firm.

Remarkable lives: Jen Waring in conversation with Jerome Carson

2016 ◽  
Vol 20 (3) ◽  
pp. 153-159
Author(s):  
Jen Waring ◽  
Jerome Carson
Keyword(s):  
Mental Health ◽  
Mental Illness ◽  
Mental Distress ◽  
Mental Health Problems ◽  
Single Case ◽  
Health Problems ◽  
Content Type ◽  
The Many ◽  
Practical Implications

Purpose – The purpose of this paper is to provide a profile of Jen Waring. Design/methodology/approach – Jen provides a short biographical description of her life. She is then interviewed by Jerome. Findings – Jen talks about her long battle with mental health problems and what has sustained her over this time. She talks about the crucial importance of support from both loved ones and professionals, as well as medication. Research limitations/implications – Single case studies are of course just one person’s story. Given Jen is an academic biologist, she not only has a unique way of looking at mental illness, she can see the potential of developing approaches in the biological understanding for people experiencing mental distress. Practical implications – Jen’s account shows the need for long-term support for more severe mental health problems. There are no quick fixes! It also highlights the need for interventions at biological, psychological and social levels. Social implications – People need “somewhere to live, someone to love and something meaningful to do” (Rachel Perkins). Many sufferers do not have all three. Services may only be able to provide two of these. Originality/value – Accounts of mental illness recovery by academics can often provide the authors with amazing insights into the world of the mentally distressed. They can also serve as an inspiration to the many students who experience mental distress.

scholarly journals Progress in rolling bearing technology for refrigerant compressors

2017 ◽  
Vol 232 (16) ◽  
pp. 2948-2961 ◽  
Author(s):  
Guillermo E Morales-Espejel ◽  
Hans H Wallin ◽  
Rudolf Hauleitner ◽  
Magnus Arvidsson
Keyword(s):  
Kyoto Protocol ◽  
Corrosion Fatigue ◽  
Rolling Bearing ◽  
Rolling Bearings ◽  
Environmental Friendly ◽  
Refrigerant Mixture ◽  
Bearing Life ◽  
Rolling Contacts ◽  
Surface Distress ◽  
New Generation

The paper describes the latest technological solutions in rolling bearings (ball and roller) used in refrigerant compressors. First, the numerous tribological challenges faced by rolling contacts in a lubricant environment made of oil and refrigerant mixture are discussed. It is followed by a description of the even tougher conditions derived by the replacement of the more chemically stable pre-Montreal and pre-Kyoto Protocol refrigerants by the new generation of more environmental friendly refrigerants. In these conditions, rolling bearings are expected to suffer from surface distress and sometimes corrosion fatigue. Thus, attempts to model these conditions by using advanced tribological models are described. Finally, descriptions of different solutions in rolling bearings in refrigerant compressors facing challenges in lubrication and bearing life are described, all the way from traditional oil–refrigerant mixture lubrication up to the latest innovation related to oil-free lubrication, namely the pure refrigerant lubrication.

scholarly journals Methodological and conceptual challenges in rare and severe event forecast-verification

2021 ◽  
Author(s):  
Philip Alexander Ebert ◽  
Peter Milne
Keyword(s):  
Skill Score ◽  
Forecast Verification ◽  
Avalanche Forecasting ◽  
Severe Event ◽  
The Many ◽  
The Relationship ◽  
Critical Overview ◽  
Practical Implications ◽  
Do So

Abstract. There are distinctive methodological and conceptual challenges in rare and severe event (RSE) forecast-verification, that is, in the assessment of the quality of forecasts involving natural hazards such as avalanches or tornadoes. While some of these challenges have been discussed since the inception of the discipline in the 1880s, there is no consensus about how to assess RSE forecasts. This article offers a comprehensive and critical overview of the many different measures used to capture the quality of an RSE forecast and argues that there is only one proper skill score for RSE forecast-verification. We do so by first focusing on the relationship between accuracy and skill and show why skill is more important than accuracy in the case of RSE forecast-verification. Subsequently, we motivate three adequacy constraints for a proper measure of skill in RSE forecasting. We argue that the Peirce Skill Score is the only score that meets all three adequacy constraints. We then show how our theoretical investigation has important practical implications for avalanche forecasting by discussing a recent study in avalanche forecast-verification using the nearest neighbour method. Lastly, we raise what we call the “scope challenge" that affects all forms of RSE forecasting and highlight how and why the proper skill measure is important not only for local binary RSE forecasts but also for the assessment of different diagnostic tests widely used in avalanche risk management and related operations. Finally, our discussion is also of relevance to the thriving research project of designing methods to assess the quality of regional multi-categorical avalanche forecasts.

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