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Article
Publication date: 19 September 2019

Qiang Li, Shuo Zhang, Yujun Wang, Wei-Wei Xu, Zengli Wang and Zhenbo Wang

Shear stresses have a considerable influence on the characteristics of lubricants and become significant at high rotating speeds. This study aims to investigate the influences of…

Abstract

Purpose

Shear stresses have a considerable influence on the characteristics of lubricants and become significant at high rotating speeds. This study aims to investigate the influences of shear cavitation (SC) on loading capacity of journal bearings.

Design/methodology/approach

A principal normal stress cavitation criterion based on the stress applied to flowing lubricant in journal bearings is developed and used to investigate SC in journal bearings. A computational fluid dynamic (CFD) model for calculating the loading capacity is established using this criterion. After validation with experimental results, the loading capacity is calculated under different conditions.

Findings

The calculation results indicate that SC intensifies when viscosity, speed and eccentricity increase. Angle of loading capacity with SC is larger than that without SC. The magnitude of loading capacity with SC is smaller than that without SC due to the decrease in the ultimate pressure. In addition, the magnitude difference between the loading capacity with and without SC increases when viscosity, speed and eccentricity increases.

Originality/value

Present research can provide some guidance for calculating the loading capacity when a journal bearing is operating at high speed or with a high viscosity lubricant.

Details

Industrial Lubrication and Tribology, vol. 71 no. 9
Type: Research Article
ISSN: 0036-8792

Keywords

Article
Publication date: 4 December 2018

Lili Wang, Qingliang Zeng, Changhou Lu and Peng Liang

This paper aims to reveal the cavitation characteristics of three oil wedges sleeve bearing and set the theoretical and experimental basis for defining the oil film boundary…

Abstract

Purpose

This paper aims to reveal the cavitation characteristics of three oil wedges sleeve bearing and set the theoretical and experimental basis for defining the oil film boundary condition.

Design/methodology/approach

Computational fluid dynamics model of three oil wedges sleeve bearings based on the Navier–Stokes equation is set using Fluent considering turbulent situation and two-phase flow theory. The cavitation characteristics of bearing is investigated by taking pictures of experiment.

Findings

The rupture region of oil film and the contours of air volume fraction increase distinctly with the increase of rotating speed and the decrease of input pressure. The critical rotating speed of cavitation occurrence and oil film pressure increases with the increase of input pressure. The change trend of experiment cavitation with the rotating speed and input pressure is consistent with theoretical cavitation in general.

Originality/value

The finite element model of three oil wedges sleeve bearings is established based on the Navier-Stokes calculation equation of the fluid, two-phase flow theory and turbulent model. Sleeve bearing is transparent, the pictures of cavitation can be easily taken by high-speed camera, the cavitation characteristics of bearing is studied by experiment. The cavitation performance of three oil wedges bearings is studied with the change of input pressure and rotating speed, the change trend is basically consistent for theory and experiment. The study on critical rotating speed of cavitation occurrence is benefit for defining the oil film boundary condition.

Details

Industrial Lubrication and Tribology, vol. 71 no. 2
Type: Research Article
ISSN: 0036-8792

Keywords

Article
Publication date: 27 April 2020

Gabriel Welfany Rodrigues and Marco Lucio Bittencourt

This paper aims to numerically investigate the surface texturing effects on the main bearings of a three-cylinder ethanol engine in terms of the power loss and friction…

Abstract

Purpose

This paper aims to numerically investigate the surface texturing effects on the main bearings of a three-cylinder ethanol engine in terms of the power loss and friction coefficient for dynamic load conditions.

Design/methodology/approach

The mathematical formulation considers the Partir-Cheng modified Reynolds equation. The mass-conserving Elrod-Adams p-θ model with the JFO approach is used to deal with cavitation. A fluid-structure coupling procedure is considered for the elastohydrodynamic lubrication. Accordingly, a 3-D linear-elastic substructured finite element model obtained from Abaqus is applied

Findings

Simulations were carried out considering different dimple texture designs in terms of location, depth and radius. The results suggested that there are regions where texturing is more effective. In addition, distinct journal rotation speeds are studied and the surface texture was able to reduce friction and the power loss by 7%.

Practical implications

The surface texturing can be a useful technique to reduce the power loss on the crankshaft bearing increasing the overall engine efficiency.

Originality/value

The surface texturing performance in a three-cylinder engine using ethanol as fuel was investigated through numerical experimentation. The results are supported by previous findings.

Peer review

The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-09-2019-0380/

Details

Industrial Lubrication and Tribology, vol. 72 no. 9
Type: Research Article
ISSN: 0036-8792

Keywords

Book part
Publication date: 1 July 2014

Gerald R. Ferris, John N. Harris, Zachary A. Russell, B. Parker Ellen, Arthur D. Martinez and F. Randy Blass

Scholarship on reputation in and of organizations has been going on for decades, and it always has separated along level of analysis issues, whereby the separate literatures on…

Abstract

Scholarship on reputation in and of organizations has been going on for decades, and it always has separated along level of analysis issues, whereby the separate literatures on individual, group/team/unit, and organization reputation fail to acknowledge each other. This sends the implicit message that reputation is a fundamentally different phenomenon at the three different levels of analysis. We tested the validity of this implicit assumption by conducting a multilevel review of the reputation literature, and drawing conclusions about the “level-specific” or “level-generic” nature of the reputation construct. The review results permitted the conclusion that reputation phenomena are essentially the same at all levels of analysis. Based on this, we frame a future agenda for theory and research on reputation.

Details

Research in Personnel and Human Resources Management
Type: Book
ISBN: 978-1-78350-824-2

Keywords

Article
Publication date: 1 April 2008

P.W. Buys

In recent times there have been major developments in the areas of digitising business information, which can impact the financial reporting supply chain. Such developments…

Abstract

In recent times there have been major developments in the areas of digitising business information, which can impact the financial reporting supply chain. Such developments include the eXtensible Business Reporting Language (XBRL) technology. The South African regulator of financial services and a major South African retirement fund administrator were recently the first South African organisations to embark on an XBRL proof of concept initiative as part of an attempt to enhance their financial reporting supply chain, from initial data recording, to the submission of the reports, to the analysis of the data. This paper provides highlights of this initiative against the background of current XBRL developments, the financial reporting supply chain and the digitising efforts of such supply chains.

Article
Publication date: 1 March 1990

Denise Francis

What it may lack in numbers, Scotland has always made up for in the independence and enterprise of its inhabitants. While Scotland cannot claim much part in the earliest stages of…

Abstract

What it may lack in numbers, Scotland has always made up for in the independence and enterprise of its inhabitants. While Scotland cannot claim much part in the earliest stages of printed circuit development, it should come as no surprise that the land which bore Alexander Graham Bell and John Logie Baird should have seized the opportunity of exploiting this other aspect of innovative technology, and that, for its mere 5 million inhabitants, it should boast a disproportionately large share of involvement in the printed circuit board industry. The total number of people involved in the PCB manufacturing industry (non‐captive market only) in England has been estimated at approximately 9,000—the numbers involved in Scotland total approximately 2,000, not far off 25% of the English figure. Wales and Ireland trail behind with about 300 and 400 respectively, while the Isle of Man, putting up a good show, numbers 16. Michael Hannon, of Michael Hannon Marketing (Ayr), comments, ‘Scottish PCB manufacturers have a disproportionate share of the UK rigid PCB home and export markets, as well as including in their number one of the largest flexible manufacturers in the UK. Out of the top five UK/Republic of Ireland PCB manufacturers’ production, the Scottish manufacturers represent about 55%. This is quite surprising when one considers that Scotland's population represents less than 10% of the total.’ Narrowing the focus from country to specific area, the Borders region is host to a number of PCB companies which together account for 55% of PCBs manufactured in Scotland, and 10% of the UK total.

Details

Circuit World, vol. 16 no. 4
Type: Research Article
ISSN: 0305-6120

Article
Publication date: 1 February 1989

M. Hannon

The EEC Nation States' 1992 Single Market awareness campaigns have achieved their objectives. The underlying EEC policies have ignited a fuse which will lead to an increase of…

Abstract

The EEC Nation States' 1992 Single Market awareness campaigns have achieved their objectives. The underlying EEC policies have ignited a fuse which will lead to an increase of Corporate Activity in the European PCB Industry. Having witnessed a rash of OEM activity including acquisitions, disposals and equity swaps there is now the feeling of the pace quickening in the PCB industry. This short paper looks at the technological implications of PCB Industry restructuring on a European scale and provides at least a taste of the larger global restructuring of which it is a part. The paper first views the European Electronics Industry restructuring and the types of deals involved, then analyses some recent PCB Industry activity before going on to draw some implications for the Technical and Production Manager. The other option, Organic growth, is not covered in this article as it is felt the reader will be more aware of this route to growth.

Details

Circuit World, vol. 15 no. 3
Type: Research Article
ISSN: 0305-6120

Article
Publication date: 1 January 2004

Nina D. Cole and Douglas H. Flint

The self‐interest and relational models of organizational justice were tested to explain the relationship between benefit plan type and organizational justice. Benefit plan types…

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Abstract

The self‐interest and relational models of organizational justice were tested to explain the relationship between benefit plan type and organizational justice. Benefit plan types considered were flexible and traditional plans. In support of the self‐interest model employees in flexible benefit plans had significantly higher perceptions of procedural justice than employees in traditional benefit plans. There were no significant differences in perceptions of distributive justice between the plan types.

Details

Journal of Managerial Psychology, vol. 19 no. 1
Type: Research Article
ISSN: 0268-3946

Keywords

Article
Publication date: 19 May 2020

Emily C. Crofton and Amalia G.M. Scannell

Using a consumer-led approach, the purpose of this research is to examine how consumers perceive new cereal-based snack food concepts using healthy brewers spent grain (BSG) as a…

Abstract

Purpose

Using a consumer-led approach, the purpose of this research is to examine how consumers perceive new cereal-based snack food concepts using healthy brewers spent grain (BSG) as a sustainable and functional ingredient.

Design/methodology/approach

In-depth laddering interviews based on means–end chain theory were conducted with 40 healthy snack consumers in Dublin, Ireland.

Findings

Four hierarchical value maps (HVM) representing data from each snack concept dimensions were generated. The results identified the crispy crackers concept as the most promising for further development, followed by crispy sticks with dip, fruity biscuits and twisted breadsticks. Consumer cognitions regarding the crispy sticks with dip and fruity biscuits were more dominantly associated with a hedonic orientation, while crispy crackers and twisted breadsticks were more strongly associated with health- related dimensions. The HVMs also identified factors which could potentially prevent the acceptance of these snacks. Although consumers displayed a level of environmental consciousness regarding the perceived packaging type, outcomes also showed that the environmental benefit of using BSG in foods is not viewed as a means to attain a desired end state in the consumers’ mind. Our findings also suggest the rich protein content of BSG is not considered relevant in the context of a cereal snack product.

Practical implications

BSG is an abundant, low-cost, nutritious waste material which is available globally in large quantities. This study provides new actionable consumer insights with important implications for snack manufacturers regarding the design and development of cereal snack foods containing this healthy by-product.

Originality/value

This study contributes to a limited body of literature by illustrating which product characteristics are considered important for consumers when selecting healthy, cereal-based snack foods using BSG as an ingredient.

Details

British Food Journal, vol. 122 no. 12
Type: Research Article
ISSN: 0007-070X

Keywords

Article
Publication date: 30 September 2008

Javed G. Hussain, Jonathan M. Scott and Paul D. Hannon

The purpose of this paper is to profile the characteristics and entrepreneurial motivations of graduate entrepreneurs from black and minority ethnic (BME) communities.

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Abstract

Purpose

The purpose of this paper is to profile the characteristics and entrepreneurial motivations of graduate entrepreneurs from black and minority ethnic (BME) communities.

Design/methodology/approach

To gather the data, the authors interviewed selected individuals from within the BME community (including current students and graduates from various universities, predominantly in the West Midlands, UK), analysed the transcripts and compared the findings with the review of literature.

Findings

Evidence suggests that BME graduate entrepreneurs were diverse in terms of their characteristics: size, gender, ethnicity and when they started the business. Almost all interviewees had worked for someone before they started their business. The two most compelling motivations for start up were “being your own boss”, especially for Indians and Bangladeshis; and making more money (31 per cent), in particular for African Caribbeans. Over half of interviewees started a business in a sector in which they had prior experience, knowledge or skills. Two thirds of interviewees obtained advice from family and friends, while just over a third had completed any kind of training or course.

Research limitations/implications

The sample of BME graduate entrepreneurs in this study was both small and selective. It was not statistically significant, nor did it represent a random selection of the BME graduate entrepreneurs in the UK or the respective population mix. Hence, there is a need for a larger scale study and the inclusion of a white control group.

Originality/value

This study provides an insight into characteristics and entrepreneurial motivations of BME graduate entrepreneurs. Though the results of this study are indicative, there is a compelling case for further research into this relatively unexplored group.

Details

Education + Training, vol. 50 no. 7
Type: Research Article
ISSN: 0040-0912

Keywords

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