Shun Cui, Hiroshi Nishikawa, Jing Wang and Qian Zou
This study aims to use a thermal elastohydrodynamic lubrication (EHL) algorithm incorporating an Eyring flow model to solve a steady-state contact in simple sliding motion.
Abstract
Purpose
This study aims to use a thermal elastohydrodynamic lubrication (EHL) algorithm incorporating an Eyring flow model to solve a steady-state contact in simple sliding motion.
Design/methodology/approach
A theoretical model was used to investigate the effect of starvation on the surface dimple phenomenon by gradually reducing the thickness of the inlet oil layer.
Findings
The increase in the starvation degree reduces the dimple depth, film thickness, the pressure peak and the temperature rise. Under the severe starvation condition, the dimple is eliminated so that the EHL contact becomes partly parched. In elliptical results, for the same starvation parameters, the oil replenishment is stronger than that in circular contact.
Originality/value
This paper fulfils an exploration to study how the oil starvation influences the surface dimple phenomenon.
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Sheri Kurgin, Jean M. Dasch, Daniel L. Simon, Gary C. Barber and Qian Zou
The purpose of this paper is to compare the performance of single- and dual-channel minimum quantity lubrication (MQL) for reaming spool bores in an automotive transmission valve…
Abstract
Purpose
The purpose of this paper is to compare the performance of single- and dual-channel minimum quantity lubrication (MQL) for reaming spool bores in an automotive transmission valve body.
Design/methodology/approach
Machining experiments are conducted under various parameters for both single- and dual-channel MQL. Comparison metrics include part surface temperature, spindle power consumption and hole quality. Experimental data from traditional through-tool flood coolant are provided as a baseline for spindle power consumption and part quality.
Findings
The results show that with proper tooling and machining parameters, dual-channel MQL can perform equivalently or better than flood coolant. Single-channel MQL was not deemed suitable for this machining application.
Practical implications
The results of the study show that MQL can be successfully applied for precision reaming of aluminum and can provide guidance in developing an MQL system.
Originality/value
Few studies have been performed for reaming holes in general, and very few studies have been performed for reaming with MQL. Reaming is a critical operation used to create holes with precise quality. No study was found in the literature review that directly compared the performance of single- and dual-channel MQL delivery systems.
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Sheri Kurgin, Jean M. Dasch, Daniel L. Simon, Gary C. Barber and Qian Zou
The purpose of this paper is to evaluate the cooling ability of minimum quantity lubrication (MQL) cutting fluid.
Abstract
Purpose
The purpose of this paper is to evaluate the cooling ability of minimum quantity lubrication (MQL) cutting fluid.
Design/methodology/approach
An experimental system is devised to find the heat transfer coefficient of MQL under simulated reaming conditions. Cooling rate of the specimen is measured with an infrared camera. The effect of air pressure and oil volume on cooling rate is tested. Metal cutting tests are performed to evaluate the effect of heat transfer coefficient on workpiece temperature.
Findings
Convective heat transfer coefficient for MQL increases with increasing air pressure. Oil volume has an indeterminate effect on the heat transfer coefficient; however, it is a dominant factor for controlling temperature during reaming.
Practical implications
The results of the study can provide guidance to optimize the temperature controlling ability of MQL for production.
Originality/value
There is limited information available in literature regarding the heat transfer coefficient of metal working fluids, particularly for MQL. In particular, experiments designed to investigate the effect of air pressure and oil volume on the heat transfer coefficient of the mist have not been previously documented. This information may be used to improve the overall cooling ability of MQL mist, thus increasing its effectiveness at controlling tool wear and maintaining part quality. The other major contribution of this work is to separate the role of the cooling and lubrication for controlling temperature while reaming aluminum. Prior to this study, there has been relatively little research performed for the reaming metal cutting operation, and still less for reaming with MQL. The nature of how metal working fluids control temperature is not fully understood, and this work provides insight as to whether cooling or lubrication plays the dominant role for reaming.
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Erdinc Karadeniz, Serkan Yilmaz Kandir, Mehmet Balcilar and Yildirim Beyazit Onal
The purpose of this paper is to investigate the factors affecting capital structure decisions of Istanbul Stock Exchange (ISE) lodging companies.
Abstract
Purpose
The purpose of this paper is to investigate the factors affecting capital structure decisions of Istanbul Stock Exchange (ISE) lodging companies.
Design/methodology/approach
A model based on the trade‐off and pecking order theories is specified and implications of both theories are empirically tested. The model is estimated using a dynamic panel data approach for five ISE companies for the period of 1994‐2006.
Findings
The findings suggest that effective tax rates, tangibility of assets, and return on assets are related negatively to the debt ratio, while free cash flow, non‐debt tax shields, growth opportunities, net commercial credit position, and firm size do not appear to be related to the debt ratio. Although the findings partially support the pecking order theory, neither the trade‐off nor the pecking order theory exactly seem to explain the capital structure of Turkish lodging companies.
Research limitations/implications
The data used in this paper are limited to five companies traded in the ISE, since the data on other companies are not available. A more detailed analysis would use data for other companies in the industry.
Practical implications
The findings of the study clearly demonstrate the importance of capital structure decisions for financial sources.
Originality/value
Although the capital structure theory is extensively examined in the finance literature, there are fewer studies covering the tourism industry, particularly Turkey. The paper establishes the determinants of the capital structure of Turkish lodging companies. The research findings should help managers to make optimal capital structure decisions.
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Xin Zou, Lihui Zhang and Qian Zhang
The purpose of this research is to develop a time-cost optimization model to schedule repetitive projects while considering limited resource availability.
Abstract
Purpose
The purpose of this research is to develop a time-cost optimization model to schedule repetitive projects while considering limited resource availability.
Design/methodology/approach
The model is based on the constraint programming (CP) framework; it integrates multiple scheduling characteristics of repetitive activities such as continuous or fragmented execution, atypical activities and coexistence of different modes in an activity. To improve project performance while avoiding inefficient hiring and firing conditions, the strategy of bidirectional acceleration is presented and implemented, which requires keeping regular changes in the execution modes between successive subactivities in the same activity.
Findings
Two case studies involving a real residential building construction project and a hotel refurbishing project are used to demonstrate the application of the proposed model based on four different scenarios. The results show that (1) the CP model has great advantages in terms of solving speed and solution quality than its equivalent mathematical model, (2) higher project performance can be obtained compared to using previously developed models and (3) the model can be easily replicated or even modified to enable multicrew implementation.
Originality/value
The original contribution of this research is presenting a novel CP-based repetitive scheduling optimization model to solve the multimode resource-constrained time-cost tradeoff problem of repetitive projects. The model has the capability of minimizing the project total cost that is composed of direct costs, indirect costs, early completion incentives and late completion penalties.
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Xin Zou, Guangchuan Wu and Qian Zhang
Repetitive projects play an important role in the construction industry. A crucial point in scheduling this type of project lies in enabling timely movement of crews from unit to…
Abstract
Purpose
Repetitive projects play an important role in the construction industry. A crucial point in scheduling this type of project lies in enabling timely movement of crews from unit to unit so as to minimize the adverse effect of work interruptions on both time and cost. This paper aims to examine a repetitive scheduling problem with work continuity constraints, involving a tradeoff among project duration, work interruptions and total project cost (TPC). To enhance flexibility and practicability, multi-crew execution is considered and the logic relation between units is allowed to be changed arbitrarily. That is, soft logic is considered.
Design/methodology/approach
This paper proposes a multi-objective mixed-integer linear programming model with the capability of yielding the optimal tradeoff among three conflicting objectives. An efficient version of the e-constraint algorithm is customized to solve the model. This model is validated based on two case studies involving a small-scale and a practical-scale project, and the influence of using soft logic on project duration and total cost is analyzed via computational experiments.
Findings
Using soft logic provides more flexibility in minimizing project duration, work interruptions and TPC, especial for non-typical projects with a high percentage of non-typical activities.
Research limitations/implications
The main limitation of the proposed model fails to consider the learning-forgetting phenomenon, which provides space for future research.
Practical implications
This study assists practitioners in determining the “most preferred” schedule once additional information is provided.
Originality/value
This paper presents a new soft logic-based mathematical programming model to schedule repetitive projects with the goal of optimizing three conflicting objectives simultaneously.
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This paper aims to shed new light on the multinationality‐performance debate by examining the performance of standardizing versus customizing firms from Spain.
Abstract
Purpose
This paper aims to shed new light on the multinationality‐performance debate by examining the performance of standardizing versus customizing firms from Spain.
Design/methodology/approach
The reasons for variations in performance of exporting firms build on the industrial organization and resource‐based views of strategy, which are shown to be linked to the integration (standardization) versus responsiveness (customization) framework of international business. The paper also incorporates the Uppsala model and the home region nature of international business activity. It develops hypotheses for both standardizing and customizing paths of international expansion for exporting firms. The paper uses the Survey on Business Strategies which has the support of the Ministry of Industry of Spain. This databank collects data of a representative sample of the Spanish manufacturing sector. The paper uses fixed‐effects regression models for the period 2000‐2008.
Findings
The paper provides evidence on how firms with a strategy of product standardization follow an M curve‐fourth degree polynomial relationship between the degree of internationalization (DOI) and performance. In contrast, product customization firms are observed to follow an inverted M curve relationship. Furthermore, by using both models, an appropriate level of internationalization can be suggested.
Originality/value
The paper provides theoretical and empirical support for the different relationships of standardizing and customizing firms when expanding abroad. This paper is one of the first to find empirical support for an M curve relationship between the DOI and performance, and certainly is the first one testing and corroborating an inverted M curve.
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Lee Li, Gongming Qian and Zhengming Qian
The purpose of this paper is to investigate the early internationalization and the performance of small firms in technology‐intensive industries.
Abstract
Purpose
The purpose of this paper is to investigate the early internationalization and the performance of small firms in technology‐intensive industries.
Design/methodology/approach
Using a sample of 278 small US firms in technology‐intensive industries, this paper employs quantitative methodologies to test hypotheses.
Findings
The findings indicate that such organizational variables as firm size and international experience have a non‐linear, inverted U‐shaped relationship with these firms’ early internationalization. Some strategic variables, such as R&D intensity, have significant impacts, whereas others, such as advertising intensity and strategic alliances, have none. However, the interactions between these strategic variables have a more significant influence upon these firms’ early internationalization than do the individual strategic variables in isolation. Moreover, early internationalization has significant and positive impacts on the performance of these firms.
Practical implications
The paper’s findings have important managerial implications. The paper identifies the driving forces for the early globalization of small firms and provides useful guidelines for managers to manage these factors in their efforts to maximize firm performance.
Originality/value
The paper differentiates organizational factors from strategic factors against the background of small “born globals” in technology industries and investigates the interactions among these internal factors and external factors, i.e. the environments of technology industries. Findings of non‐linear relationships among these factors shed light on the strategy determinants of a unique group of small to medium‐sized enterprises and their performance.
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Jingtao Yi, Yi Zhong and Qian Zheng
The purpose of this paper is to investigate factors that account for variations in the export performance between private‐owned enterprises (POEs) and state‐owned enterprises from…
Abstract
Purpose
The purpose of this paper is to investigate factors that account for variations in the export performance between private‐owned enterprises (POEs) and state‐owned enterprises from the perspective of value chain.
Design/methodology/approach
The authors conducted empirical analysis with the panel data of 19 industrial sectors in China between 2005 and 2007.
Findings
This study finds that labor input, state ownership and vertical specialization have positive effects on export performance while capital and technology inputs have negative effects. In particular, the study found that the superior export performance of state‐owned enterprises to private‐owned ones can be mainly explained by their positions of vertical specialization in the upper stage along the industrial value chain.
Practical implications
The paper shows that, given the significance of POEs in China's economy and foreign trade, restrictions on POEs to enter certain high‐end industrial sectors should be relaxed and policy makers should undertake favourable policies to help POEs to engage in high‐end activities along the industrial value chain.
Originality/value
Although export performance has always been a heated topic in both economics and business studies, the value chain perspective has been rarely investigated and this paper fills the research gap.
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Mohammad A. Gharaibeh and Faris M. Al-Oqla
There are several lead-free solder alloys available in the industry. Over the years, the most favorable solder composition of tin-silver-copper (Sn-Ag-Cu [SAC]) has been vastly…
Abstract
Purpose
There are several lead-free solder alloys available in the industry. Over the years, the most favorable solder composition of tin-silver-copper (Sn-Ag-Cu [SAC]) has been vastly used and accepted for joining the electronic components. It is strongly believed that the silver (Ag) content has a significant impact on the solder mechanical behavior and thus solder thermal reliability performance. This paper aims to assess the mechanical response, i.e. creep response, of the SAC solder alloys with various Ag contents.
Design/methodology/approach
A three-dimensional nonlinear finite element simulation is used to investigate the thermal cyclic behavior of several SAC solder alloys with various silver percentages, including 1%, 2%, 3% and 4%. The mechanical properties of the unleaded interconnects with various Ag amounts are collected from reliable literature resources and used in the analysis accordingly. Furthermore, the solder creep behavior is examined using the two famous creep laws, namely, Garofalo’s and Anand’s models.
Findings
The nonlinear computational analysis results showed that the silver content has a great influence on the solder behavior as well as on thermal fatigue life expectancy. Specifically, solders with relatively high Ag content are expected to have lower plastic deformations and strains and thus better fatigue performance due to their higher strengths and failure resistance characteristics. However, such solders would have contrary fatigue performance in drop and shock environments and the low-Ag content solders are presumed to perform significantly better because of their higher ductility.
Originality/value
Generally, this research recommends the use of SAC solder interconnects of high silver contents, e.g. 3% and 4%, for designing electronic assemblies continuously exposed to thermal loadings and solders with relatively low Ag-content, i.e. 1% and 2%, for electronic packages under impact and shock loadings.