Research on different structures of dimpled textures on improving the LE-FPL of engine

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Peiling Wang ◽  
Vanliem Nguyen ◽  
Xiaoyan Wu ◽  
Shu Wang
Keyword(s):  
Optimal Design ◽  
Coefficient Of Friction ◽  
Power Loss ◽  
Design Methodology ◽  
Operating Conditions ◽  
Asperity Contact ◽  
Content Type ◽  
Better Than ◽  
Engine Power ◽  
Oil Film Pressure

Purpose This paper aims to research the effect of the different structures of dimpled textures on the rod bearing surfaces on improving the engine’s lubrication efficiency and friction power loss (LE-FPL). Design/methodology/approach Based on the hydrodynamic model of the rod bearing, the effect of different structures of dimpled surfaces including circular dimples (CD), square dimples (SD), wedge-shaped dimples (WSD), circular-square dimples (CSD) and square-wedge-shaped dimples (SWSD) on ameliorating the LE-FPL is analyzed under the different operating conditions of the engine. The oil film pressure (p), asperity contact force (Wac), friction force (Ff) and coefficient of friction (COF) of the rod bearing are chosen to evaluate the LE-FPL. Findings The SD’s performance on improving the LE-FPL is better than all other structures of the CD, WSD, CSD and SWSD. Particularly, the average values of Wac, Ff and COF with the SD is significantly reduced by 14.5%, 28.5% and 33.3% compared to the optimal dimensions of the rod bearing; and by 26.4%, 34.5% and 43.7% compared to the optimal CD (n = m = 6). Originality/value The generated friction between surfaces of rod bearings of the engine not only reduces the engine power but also affects the durability of the structures. Thus, the optimal design of the SD to further improve the LE-FPL is very necessary.

Effects of piston design parameters on skirt-liner dynamic behavior

2016 ◽  
Vol 68 (2) ◽  
pp. 250-258 ◽  
Author(s):  
Ridha Mazouzi ◽  
Ahmed Kellaci ◽  
Abdelkader Karas
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Power Loss ◽  
Design Methodology ◽  
Great Influence ◽  
Structural Deformation ◽  
Design Parameters ◽  
Content Type ◽  
Piston Cylinder ◽  
Oil Film Pressure

Purpose – This paper aims to study the effect of piston skirt design parameters on the dynamic characteristics of a piston–cylinder contact. Design/methodology/pproach – This paper focuses on an analysis of the piston dynamic response. The oil-film pressure and the structural deformation were approximated, respectively, by finite difference method and finite element method. Findings – The results show that the design parameters such as clearance, offset and the axial location of piston pin have a great influence on the dynamics of the piston and hence on the piston slap phenomenon and the frictional power loss. Originality/value – All the results mainly focus on the slap noise of the engine and can be used in the piston–liner development at the development of the engine.

Current CITE-ings from the popular and trade computing press: telework and telecommuting

2016 ◽  
Vol 33 (1) ◽  
pp. 21-22 ◽  
Author(s):  
Martin Kesselman
Keyword(s):  
Literature Review ◽  
Design Methodology ◽  
Virtual Reference ◽  
Content Type ◽  
Advantages And Disadvantages ◽  
Better Than

Purpose – This article examines Current CITE-ings from the Popular and Trade Computing Press, Telework and Telecommuting Design/methodology/approach – The methodology adopted is a literature review. Findings – Readily available technologies now allow librarians to perform most of their work-offsite. Some traditional building-based services such as reference, have been taken over by virtual reference and now even instruction offers options on par with or even better than classroombased questions such as a webinar that can be viewed and reviewed at any time or by having librarians embedded into various courseware packages. Researchlimitations/implications – Librarians no longer need be limited to a single library; groups of subject librarians can work together in the cloud to provide services to multiple universities. Originality/value – This article collates some articles from the non-library literature that mayprovide some ideas and review advantages and disadvantages for both the library and employee

Research on thermal property and temperature rating prediction of Mongolian robe ensembles

2018 ◽  
Vol 30 (6) ◽  
pp. 747-756 ◽  
Author(s):  
Xiaofang Guo ◽  
Hui Shi ◽  
Chenglong Wei ◽  
Xiao Dong Chen
Keyword(s):  
Prediction Model ◽  
Thermal Property ◽  
Thermal Insulation ◽  
Design Methodology ◽  
Environmental Adaptation ◽  
Photographic Method ◽  
Mongolian Plateau ◽  
Content Type ◽  
Research Findings ◽  
Better Than

Purpose The purpose of this paper is to reveal the unique thermal property of Mongolian clothing from the current western clothing and explain their environmental adaptation to the climate of Mongolian plateau in China. Design/methodology/approach Thermal insulation and the temperature rating (TR) of eight Mongolian robe ensembles and two western clothing ensembles were investigated by manikin testing and wearing trials, respectively. The clothing area factor (fcl) of these Mongolian clothing was measured by photographic method and estimated equation from ISO 15831. Finally, the TR prediction model for Mongolian clothing was built and compared with current models for western clothing in ISO 7730 and for Tibetan clothing in previous article. Findings The results demonstrated that the total thermal insulation of Mongolian robe ensembles was much bigger than that of western clothing ensembles and ranged from 1.81clo to 3.11clo during the whole year. The fcl of the Mongolian clothing should be determined by photographic method because the differences between these two methods were much bigger from 0.6 to 13.9 percent; the TR prediction model for Mongolian robe ensembles is TR=25.57−7.13Icl, which revealed that the environmental adaptation of Mongolian clothing was much better than that of western clothing and similar to that of Tibetan clothing. Originality/value The research findings give a detailed information about the thermal property of China Mongolian clothing, and explain the environmental adaptation of Mongolian clothing to the cold and changing climate.

Modeling schedule overrun and cost escalation percentages of highway projects using fuzzy approach

2017 ◽  
Vol 24 (5) ◽  
pp. 809-827 ◽  
Author(s):  
Ahmed Ebrahim Abu El-Maaty ◽  
Amr M. El-Kholy ◽  
Ahmed Yousry Akal
Keyword(s):  
Linear Regression ◽  
Design Methodology ◽  
Fuzzy Theory ◽  
Linear Regression Analysis ◽  
Fuzzy Approach ◽  
Analysis Method ◽  
Highway Projects ◽  
Content Type ◽  
Theoretical And Numerical Analysis ◽  
Better Than

Purpose Modeling represents the art of translating problems from an application area into tractable mathematical formulations whose theoretical and numerical analysis provides insight, answers and guidance useful for the originating application. The purpose of this paper is to determine the causal causes of schedule overrun and cost escalation of highway projects in Egypt in order to be used as independents variables in mathematical models for predicting the percentages of schedule overrun and cost escalation of such projects in Egypt. Design/methodology/approach A survey of a randomly selected samples yielded responses from 40 owners, 15 consultants and 56 contractors. The survey includes 38 schedule overrun factors and 26 cost escalation factors. The effectiveness degree of the identified factors has been identified by the triangle fuzzy approach. Findings The results of the survey show that “contractor’s technical staff is insufficient and ineligible to accomplish the project” is the most important cause of schedule overrun, while the major cause of cost escalation is inadequate preparation of the project concerning planning and execution. Originality/value The main contribution of this study is predicting the percentages of schedule overrun and cost escalation of highway projects in Egypt. Through the application of the linear regression analysis method and statistical fuzzy theory, four predictive models have been developed and it has been noted that the linear regression-based model shows prediction accuracy better than statistical fuzzy-based model in predicting percentages of schedule overrun and cost escalation.

Simulation studies on static thermal behaviour of true elliptical and orthogonally displaced non-circular journal bearing

2016 ◽  
Vol 68 (3) ◽  
pp. 349-360 ◽  
Author(s):  
Amit Singla ◽  
Amit Chauhan
Keyword(s):  
Journal Bearing ◽  
Load Capacity ◽  
Current Trend ◽  
Operating Conditions ◽  
Performance Characteristics ◽  
Film Pressure ◽  
Content Type ◽  
Oil Film ◽  
Ellipticity Ratio ◽  
Oil Film Pressure

Purpose The current trend of modern industry is to use machineries which rotate at high speed along with the capability of carrying heavy rotor loads. This paper aims at static thermal analysis of two different profiles of non-circular journal bearings – a true elliptical bearing and orthogonal bearing. Design/methodology/approach The Reynolds equation has been solved through finite difference method to compute the oil film pressure. Parabolic temperature profile approximation technique has been used to solve the energy equation and thus used for computation of various bearing performance characteristics such as thermo-hydrodynamic oil film pressure, temperature, load capacity, Sommerfeld number and power loss characteristics across the bearing. The effect of ellipticity ratio on the bearing performance characteristics has also been obtained for both the elliptical and vertical offset bearing using three different commercially available grades of oil (Hydrol 32, 68 and 100). Findings It has been observed that the thermo-hydrodynamic pressure and temperature rise of the oil film is less in orthogonal bearing as compared to the true elliptical bearing for same operating conditions. The effect of ellipticity ratio of non-circularity on bearing performance parameters have been observed to be less in case of elliptical bearing as compared to orthogonal bearing. It has been concluded that though the rise in oil film temperature is high for true elliptical bearing, but still it should be preferred over orthogonal profile under study, as it has comparably good load-carrying capacity. Originality/value The performance parametric analysis will help the designers to select such kind of non-circular journal bearing for various applications.

scholarly journals Better than before: the resilient organization in crisis mode

2018 ◽  
Vol 39 (1) ◽  
pp. 32-42 ◽  
Author(s):  
Epaminondas Koronis ◽  
Stavros Ponis
Keyword(s):  
Crisis Management ◽  
Design Methodology ◽  
Organizational Characteristics ◽  
Managerial Ability ◽  
Organizational Survival ◽  
Research Directions ◽  
Learning Abilities ◽  
Content Type ◽  
Practical Implications ◽  
Better Than

Purpose The paper aims to adopt a strategic view of organizational survival and argue that preparedness, responsiveness, adaptability and learning abilities constitute organizational drivers of resilience and provide a new direction on crisis management. Design/methodology/approach As a conceptual and literature exploration, the methodological focus is to combine various concepts within a unified model for resilience. Findings The proposed conceptual model highlights the need for strategic reconfigurations toward the construction of a resilience culture and the development of a supporting social capital in organizations. It also portrays organizational survival and sustainability as being dependent on strategic characteristics rather than on the managerial ability to handle situations and manage crisis. Research limitations/implications In this paper, implications, methodological concerns in the study of resilience and further research directions have been presented. Practical implications The paper approaches a new way of thinking about crises and provides a set of cultural and organizational characteristics that would increase resilience and crisis management abilities. Originality/value While organizations are nowadays more than ever affected by disruptions and crises, their inherent ability and strategies to protect their sustainability have been undertheorized. This paper aims at contributing to a growing and fruitful discussion.

Reaching for ripeness: promoting negotiation through unilateral conciliatory action

2019 ◽  
Vol 30 (2) ◽  
pp. 180-201 ◽  
Author(s):  
Johnston S. Barkat
Keyword(s):  
Resource Sharing ◽  
Design Methodology ◽  
Identity Conflict ◽  
Content Type ◽  
Resource Conflict ◽  
Resource Conflicts ◽  
Economic Aid ◽  
Identity Based ◽  
Better Than ◽  
Do So

PurposeWhile the process of negotiation has been studied extensively, little research has been done on the factors that lead parties to the negotiation table. In light of this, the purpose of this paper is to examine effects of unilateral conciliatory initiatives (UCIs) (actions) on the willingness and preparedness of parties to negotiate.Design/methodology/approachThe study used a separate-sample posttest, 2 × 3 factorial design. Subjects were placed into simulated intractable resource- and identity-based conflicts. Groups then received UCIs (in the form of economic aid and apology) intended to benefit the other and contribute to a high commitment to de-escalation (ripeness). Ripeness was measured by increased empathy; and decreased distrust, escalatory behaviors (operationalized as aggression and autistic hostility), anger, win-lose/competitive orientation and negative attributions.FindingsUCIs were shown to impact both the state and the process of ripeness. Apology facilitated ripeness in an identity conflict and positively impacted five of the six resistance areas in a resource conflict. Economic aid likewise affected ripeness in an identity conflict but did not impact a resource conflict better than an apology. The offer of an apology affected empathy in both conflict types but economic aid did not do so in a resource conflict. It was also observed that an identity-based conflict produced less trust and increased negative attributions than did a resource conflict.Originality/valueThis suggests that identity and resource conflicts activate some resistance areas differently. It also reveals that similar interventions may be effective in both conflicts but that each UCI affects particular resistance areas differently. The findings suggest that there should be an increased emphasis on apology by conflict resolution practitioners. The practical and theoretical implications of apologies and resource sharing in de-escalation are discussed, to facilitate their appropriate use in resolution strategies that reduce tensions within conflict.

scholarly journals Chemical vegetable safety in China: “supermarketisation” and its limits

2020 ◽  
Vol 122 (11) ◽  
pp. 3433-3449
Author(s):  
Lita Alita ◽  
Liesbeth Dries ◽  
Peter Oosterveer
Keyword(s):  
Food Safety ◽  
Value Chain ◽  
Design Methodology ◽  
Urban China ◽  
Value Chains ◽  
Small Scale ◽  
Retail Sector ◽  
Content Type ◽  
Food Value ◽  
Better Than

PurposeThe purpose of this paper is to analyze the process of supermarketization in the vegetable retail sector in China and its impact on food safety.Design/methodology/approachData from food safety reports by the Chinese Food and Drug Administration (CFDA) are used to investigate the degree of vegetable safety in different value chain types. To assess the predictors of the degree of vegetable safety, a logistic regression model is applied.FindingsSupermarketization has led to the reorganization of the vegetables provision system, through closer coordination along the supply chain and the use of secured production bases. We identify four types of vegetable value chains in China based on their form of coordination. Supermarkets improve vegetable safety even when they rely on external suppliers, but also wet markets perform significantly better than other small-scale retailers in terms of vegetable safety.Originality/valueThe study has expanded the knowledge of the supermarketization in urban China by collecting data from CFDA. Furthermore, the study used the theory of food value chain to understand determinant factors in securing food safety. Moreover, this study reveals that wet markets also have prospects in solving vegetable safety problems in China, especially in underdeveloped areas.

Design and optimization of textures on the surface of crankpin bearing to improve lubrication efficiency and friction power loss of engine

2020 ◽  
pp. 135065012094200
Author(s):  
Zhenpeng Wu ◽  
Vanliem Nguyen ◽  
Vanquynh Le ◽  
Xuanlong Le ◽  
Vancuong Bui
Keyword(s):  
Power Loss ◽  
Asperity Contact ◽  
Bearing Surface ◽  
Film Pressure ◽  
Oil Film ◽  
Design And Optimization ◽  
Friction Power ◽  
Study Results ◽  
The Impact ◽  
Oil Film Pressure

The study proposes a design and optimization of textures on the surface of crankpin bearing to improve the lubrication efficiency and friction power loss (LE-FPL). A hydrodynamic lubrication model of crankpin bearing considering the impact of the external dynamic load and micro asperity contact is established. Based on the established model, the lubrication textures designed on the bearing surface are then simulated and optimized through the algorithms developed in Matlab environment and multi-objective optimization method. Increasing the oil film pressure and reducing the contact force ( Wac) in the asperity contact region, friction force ( Ff), and friction coefficient ( µ) of crankpin bearing are the objective functions to evaluate the LE-FPL. The study results indicate that the lubrication textures designed on the bearing surface have an obvious effect on improving the LE-FPL. Especially, with the optimized textures, the maximum oil film pressure is greatly increased by 44.8% while the maximum values of Wac and Ff are significantly reduced by 22% and 25%. Consequently, the lubrication textures added on the surface of crankpin bearing can greatly improve the LE-FPL.

The acquisition of the Arabic construct state (CS) constructions by Arabic-speaking children with ASD

2019 ◽  
Vol 5 (4) ◽  
pp. 255-267 ◽  
Author(s):  
Abdel Rahman Mitib Altakhaineh ◽  
Razan N. Alkhatib
Keyword(s):  
Autism Spectrum Disorder ◽  
Design Methodology ◽  
Children With Autism ◽  
Autism Spectrum ◽  
Head Direction ◽  
Content Type ◽  
Children With Asd ◽  
Different Types ◽  
Arabic Speaking ◽  
Better Than

PurposeThe purpose of this paper is to investigate whether age plays a role in the acquisition of construct state (CS) constructions in Arabic by 14 children with autism spectrum disorder (ASD). It also examined the challenges faced by children with ASD in producing different types of CS constructions. Finally, the study analysed the sources of difficulties children with ASD encounter during the learning process of the CS.Design/methodology/approachFor the purposes of this study, the participants were asked to orally complete short sentences with the help of illustrative pictures.FindingsResults revealed that the age of the 14 children with ASD plays a role in the acquisition of CS constructions. Children of age 12–15 performed better than those of age 8 and 10. Results also showed that children with ASD performed better in producing phrases rather than compounds. Moreover, the participants performed better on endocentric compounds as opposed to exocentric ones. Finally, analysing the errors produced on the text revealed that the acquisition of head direction precedes definiteness.Originality/valueThe topic of the study has not been investigated yet and the study concluded with some important findings concerning teaching Arabic CS to children with ADS.

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