Yuan Kang, Ping‐Chen Shen, Cheng‐Hsign Chen, Yeon‐Pun Chang and Hsing‐Han Lee
This paper seeks to modify the determinations of flow rate and fluid resistance, which can be realized and confident from the measurements of flow rates in experiments.
Abstract
Purpose
This paper seeks to modify the determinations of flow rate and fluid resistance, which can be realized and confident from the measurements of flow rates in experiments.
Design/methodology/approach
According to coupled physics of solid membrane and lubrication fluid, finite element method is used simultaneously to determine membrane deflection and film thickness. Several cases are simulated by traditional method, finite element method and compared with experimental method for the flow rates and fluid resistances to present the modification of determination results.
Findings
The FEM results for the fixed eight‐section are approximated to actual flow rate and are consistent with the modified determination of the flow rates, and so the modified determinations of the flow rates are verified. When a computer of P4 with 1.8 GHz CPU and 512 MB RAM is utilized, time needed for traditional method or modified formula is fewer than one second. However, more than 4 h is required for FEM by using the same computer.
Originality/value
This study provides the modified method for the determinations of flow rate and fluid resistance in membrane‐type restrictors by using FEM. The FEM results can increase the determination accuracy of the flow rate and restriction coefficient in the design of membrane‐type restrictors.
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Cheng‐Hsien Chen, Yuan Kang, Yeon‐Pun Chang, Hsing‐Han Lee and Ping‐Chen Shen
The present paper proposes a theoretical analysis of the stability characteristics of a Jeffcott rotor‐hybrid bearing system. It is intended that on the basis of the numerical…
Abstract
Purpose
The present paper proposes a theoretical analysis of the stability characteristics of a Jeffcott rotor‐hybrid bearing system. It is intended that on the basis of the numerical results drawn from this study, appropriate recess depth, land size, orifice location and speed parameter for stable operation can be determined for use in the bearing design process.
Design/methodology/approach
A Jeffcott rotor supported by hybrid oil film bearings with dual‐row recesses and orifice‐ compensated restrictors is studied. In order to facilitate the calculation of film dynamics, using the perturbation method, the Reynolds equation was linearized and subsequently solved using finite difference techniques, whilst the stability maps were determined by the Routh‐Hurwitz method.
Findings
The data reported here suggest that the stability characteristics of the Jeffcott rotor‐bearing system could be improved by the use of shallow, dual‐recessed hybrid bearings with orifice compensation. In addition to greater eccentricity ratios, smaller land‐width ratios and greater shaft stiffness may also provide shallow‐recessed bearings with better stability. In all cases, the stability provided by upstream orifice‐sited bearings is better than that provided by center orifice‐sited bearings, whilst high‐speed parameters may also provide a greater stability threshold.
Originality/value
This study proposes an extensive database as a critical requirement in the design of hybrid bearings, in order to ensure that a rotor bearing system is operating stably.
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Yuan Kang, Ping‐Chen Shen, Cheng‐Hsien Chen, Chih‐Ching Huang and Lin‐Kan Yang
All deep‐groove ball bearings have similar features in geometry, mechanism, and structure. Stiffness of this type of bearings is related to geometry, dimensions, and operating…
Abstract
All deep‐groove ball bearings have similar features in geometry, mechanism, and structure. Stiffness of this type of bearings is related to geometry, dimensions, and operating conditions by a very complex, high‐order and coupled‐variable function. This paper has verified that the stiffness function for all deep‐groove ball bearings can be replaced by a back‐propagation neural network (BPNN) which is trained by using some (not all) samples.
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Chun-Hsiao Wang and Yu-Ping Chen
The purpose of this study is to develop a conceptual model explicating the development of expatriate social capital and its influence on expatriate effectiveness in terms of…
Abstract
Purpose
The purpose of this study is to develop a conceptual model explicating the development of expatriate social capital and its influence on expatriate effectiveness in terms of knowledge transfer and adjustment. Drawing upon social capital theory and weak tie theory, we elucidate the process through which expatriate social capital facilitates expatriate knowledge transfer and adjustment via greater access of role information and social support.
Design/methodology/approach
This study reviews and distills research on expatriate social capital development and proposes a conceptual model of expatriate effectiveness and suggests potential research avenues for global mobility scholars.
Findings
This study contributes to the understanding of the development of expatriate social capital in the host country and its impacts on expatriate effectiveness as a process. With regard to expatriates’ social capital accumulation, this study also highlights the important but less-known role of accompanying spouse/family members as expatriates’ weak tie enablers. We articulate a framework that outlines the sources of social capital for expatriates and the processes through which social capital transmits (via expatriates’ access to role information and social support) and then enhances expatriate effectiveness. This conceptual model aims to establish a basic “roadmap” for use by practitioners and researchers.
Research limitations/implications
Before the proposed conceptual model can be theoretically refined or extended by future research, its veracity needs to be tested empirically. Although we do not incorporate “time,” “personal characteristics” and “context” in our model, we recognize their potential importance and urge future researchers to incorporate them in studying the role of social capital on expatriate effectiveness.
Practical implications
A conceptual model is presented that enables multinational corporations (MNCs) to map their current (and future) strategies to enhance expatriate effectiveness by further strengthening the expatriate social capital.
Originality/value
Drawing upon social capital theory and weak tie theory, this paper links various sources of expatriate social capital to expatriates’ access to role information and social support in supporting expatriate effectiveness. From this, several avenues of future research are drawn.
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I‐En Liao, Wen‐Chiao Hsu, Ming‐Shen Cheng and Li‐Ping Chen
The purpose of this paper is not only to design a more effective recommendation system for libraries, but also to eliminate many of the weaknesses found in the existing library…
Abstract
Purpose
The purpose of this paper is not only to design a more effective recommendation system for libraries, but also to eliminate many of the weaknesses found in the existing library recommender systems.
Design/methodology/approach
A novel library recommender system was designed for English collections by integrating personal ontology model and collaborative filtering model with domain specification.
Findings
The trend of the traditional library is evolving toward that of digital library. The personal ontology recommender (PORE) system offers a friendly user interface and provides several personalized services.
Research limitations/implications
This system is only implemented and tested in the Library of National Chung Hsing University in Taiwan.
Originality/value
The paper demonstrates a good methodology to offer an active, effective, and personalized recommendation system for library patrons.
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Ke Li, Xiuping Dong, Mingji Huang and Ping Chen
This paper aims to improve the wear resistance of metal rubber microfilaments and the service life. The effect of surface texture by laser processing on the fretting friction…
Abstract
Purpose
This paper aims to improve the wear resistance of metal rubber microfilaments and the service life. The effect of surface texture by laser processing on the fretting friction properties of metal rubber microfilaments was studied.
Design/methodology/approach
The LQL-F20A laser marking machine was used to fabricate a ring groove array with equal spacing and dense arrangement on the surface of metal rubber microfilaments. The test was carried out with a self-made micro-dynamic frictional tester. The topography of the microfilaments was observed by scanning electron microscopy and analyzed.
Findings
It has shown that laser surface texturing can improve the wear performance of microfilaments. Under the same experimental conditions, the microfilaments of textured surface has a smaller depth of wear than un-textured specimen. The wear resistance increases with the increase of texture density. The friction coefficient of textured specimen is significantly reduced compared with un-textured specimen, and the surface texture density of microfilaments has little influence on the friction coefficient after stabilization. In the stage of stable fretting wear, the wear depth will be more with the increase of the load.
Originality/value
There is little research on metal rubber microfilaments tribological properties. In this paper, the effect of laser texturing of microfilaments on micro-dynamic friction properties was studied by friction machine to provide a reference for the application of metal rubber in aerospace, medical and other fields.