B. Fiegl, M. Hibler, W. Kiffe, F. Koch, R. Kuhnert, R. Messer and H. Schwarzbauer
Module technology has become the most successful technology for power devices. The sandwich structure of the module serves as both an electrical insulator and heat sink to remove…
Abstract
Module technology has become the most successful technology for power devices. The sandwich structure of the module serves as both an electrical insulator and heat sink to remove the heat generated in the device. Typical heat fluxes of 200 W/cm2 through the chip substrate interface make it necessary to develop modules with a lower thermal resistance than those available today. With the recent advances in diamond technology, diamond substrates which have unique heat conducting properties are now available. Presented here are the first applications of diamond films in power device modules in combination with a new joining technology. The thermal behaviour of these modules has been simulated. Following the simulations, power device modules with a diamond film were produced. Investigations with a scanning acoustic microscope showed that there is good mechanical contact between the diamond and the adjacent layers. The thermal resistance of the modules was measured. The results are in good agreement with those of the simulations. They show that the application of diamond films in power modules for heat conduction and heat spreading is feasible. It is demonstrated that diamond films together with an advanced joining technology provide a considerable improvement in thermal management compared with state‐of‐the‐art technologies.
Kaisa Henttonen, Minna Janhonen, Jan‐Erik Johanson and Kaisu Puumalainen
Businesses are increasingly using teams as their fundamental organisational unit. This paper aims to explore the impact of demographic antecedents and the social‐network…
Abstract
Purpose
Businesses are increasingly using teams as their fundamental organisational unit. This paper aims to explore the impact of demographic antecedents and the social‐network structure, measured in terms of task‐related advice‐network density, centralisation and fragmentation, on work‐team performance. The paper seeks to examine: the impact of the social‐network structure (dense, fragmented or centralised) on work‐team performance and the origins of the social structure. It also tests whether team diversity (in terms of variety with regard to gender and separation with regard to age and education) has an impact on team performance.
Design/methodology/approach
A survey was conducted on 76 work teams (499 employees) representing 48 different organisations.
Findings
With regard to the first question, density was positively related to team performance. The impact of advice‐network fragmentation was also positive, and this is in line with the results of other studies focusing on teams conducting standard tasks. In addressing the second question the paper explored whether diversity as variety (age) and diversity as separation (age and education) had an effect on the work team's social‐network structure. Age and education had no effect, but gender diversity was related negatively to density and positively to fragmentation. It was also related negatively to team performance.
Originality/value
The contribution of this research is twofold in that it explores social‐structure effects on team performance and examines the possible antecedents of the team's social structure. The results of the investigation strengthen the rationale behind integrating the literature on social‐network analysis and teams.
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Every writer, Nietzsche once commented, has an intellectual idiosyncrasy that, once grasped, can be used as a key to interpret their work. In Chester Barnard’s classic text on…
Abstract
Every writer, Nietzsche once commented, has an intellectual idiosyncrasy that, once grasped, can be used as a key to interpret their work. In Chester Barnard’s classic text on management theory, The Functions of the Executive, the use of dichotomy is such a key. Barnard uses dichotomy in all his major conceptual frameworks. Analyses his three central sociological concepts: society, organization purpose, and organization authority. Shows that the purpose behind Barnard’s use of dichotomy is political: he is attempting to legitimate the dominance of formal organization in society. His main means to accomplish this is by defining dichotomies in such a way that they either assume the dominance or demonstrate the superiority of formal organization. The result is that Barnard’s use of dichotomy is misleading and contradictory. He tries to conceal the contradictions by the use of complex and ambiguous discussions. Ultimately, Barnard’s theoretical method is shown to rest on the erroneous dichotomy that assumes organization rationality is autonomous from and superior to culture and society.
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Boussad Abbes, Tahar Anedaf, Fazilay Abbes and Yuming Li
Direct energy deposition (DED) is an additive manufacturing process that allows to produce metal parts with complex shapes. DED process depends on several parameters, including…
Abstract
Purpose
Direct energy deposition (DED) is an additive manufacturing process that allows to produce metal parts with complex shapes. DED process depends on several parameters, including laser power, deposition rate and powder feeding rate. It is important to control the manufacturing process to study the influence of the operating parameters on the final characteristics of these parts and to optimize them. Computational modeling helps engineers to address these challenges. This paper aims to establish a framework for the development, verification and application of meshless methods and surrogate models to the DED process.
Design/methodology/approach
Finite pointset method (FPM) is used to solve conservation equations involved in the DED process. A surrogate model is then established for the DED process using design of experiments with powder feeding rate, laser power and scanning speed as input parameters. The surrogate model is constructed using neutral networks (NN) approximations for the prediction of maximum temperature, clad angle and dilution.
Findings
The simulations of thin wall built of Ti-6Al-4V titanium alloy clearly demonstrated that FPM simulation is successful in predicting temperature distribution for different process conditions and compare favorably with experimental results from the literature. A methodology has been developed for obtaining a surrogate model for DED process.
Originality/value
This methodology shows how to achieve realistic simulations of DED process and how to construct a surrogate model for further use in optimization loop.
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Kaisa Henttonen, Jan-Erik Johanson and Minna Janhonen
– The focus in this paper is on the extent to which bonding and bridging social relationships predict the performance effectiveness and attitudinal (identity) outcomes.
Abstract
Purpose
The focus in this paper is on the extent to which bonding and bridging social relationships predict the performance effectiveness and attitudinal (identity) outcomes.
Design/methodology/approach
The research was survey-based, involving 76 work teams and a total of 499 employees in 48 organisations.
Findings
The analysis reveals a positive relationship between both bonding and bridging relationships and performance effectiveness and attitudinal outcomes. Team identity mediates the relationship between the team ' s social-network structure and its performance effectiveness.
Research limitations/implications
The research investigates the performance effectiveness and attitudinal outcomes of social networks simultaneously, which is rare, but for study-design reasons fails to investigate behavioural outcomes. More extensive data would reveal more about the possible interaction between bridging and bonding.
Practical implications
In order to improve performance effectiveness managerial attention should focus on building a team and social networks.
Originality/value
The research shows that team identity fully mediates the influence of bonding and bridging social relationships. This finding sheds light on the processes that mediate performance effectiveness, which in turn facilitate understanding of how team dynamics lead to differing performance levels. The results also reveal how the type of social network affects the creation of a team identity: individuals identify with the team through the social networks to which they belong both within it and outside. Thus, team identity matters given the evidence suggesting that those who identify more with their work teams perform more effectively.
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Ankur Nandedkar and Roger S. Brown
A significant amount of research has examined the relationship between transformational leadership and positive follower outcomes such as organizational citizenship behavior (OCB…
Abstract
Purpose
A significant amount of research has examined the relationship between transformational leadership and positive follower outcomes such as organizational citizenship behavior (OCB) and task performance. Building on the social exchange theory and referent cognitions theory, this paper explores the propositions that transformational leadership, OCB and task performance relationship are mediated by leader member exchange (LMX) and distributive justice. The purpose of this paper is to explore the underlying mechanism that has a potential to influence the transformational leadership and follower outcomes relationship. The authors also discuss the implications for management theory and practice.
Design/methodology/approach
The primary goal of the research is theory building, so the paper is using a conceptual research design.
Findings
The authors find the assumption that the supervisors evaluate the performance of their employees and the performance evaluation has a strong influence on the allocation of rewards to be reasonable. Despite being reasonable, in some circumstances, the rewards allocation maybe dictated by upper management or the HR department; thus, the authors will need to gather a few more details in the survey to address this limitation.
Originality/value
This study presents a research model which emphasizes on the role of LMX and distributive justice in the linkage of transformational leadership and positive work outcomes. More specifically, the authors argue that follower outcomes such as OCB and task performance are a result of not only the high-quality LMX between transformational leaders and followers but also the distributive justice perceptions of followers.
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This paper aims to find proper technological parameters of low-temperature joining technique by silver sintering to eventually use this technique for reliable electronic packaging.
Abstract
Purpose
This paper aims to find proper technological parameters of low-temperature joining technique by silver sintering to eventually use this technique for reliable electronic packaging.
Design/methodology/approach
Based on the literature and author’s own experience, the factors influencing the nanosized Ag particle sintering results were identified, and their significance was assessed.
Findings
It has been shown that some important technological parameters clearly influence the quality of the joints, and their choice is unambiguous, but the meaning of some parameters is dependent on other factors (interactions), and they should be selected experimentally.
Originality/value
The value of this research is that the importance of all technological factors was analyzed, which makes it easy to choose the technological procedures in the electronic packaging.
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Qian Li, Qinshan Sun, Sha Tao and Xinglin Gao
Recently, there has been increasing focus on the development of multi-skilled workforce in project management. The purpose of this paper is to investigate a multi-skill project…
Abstract
Purpose
Recently, there has been increasing focus on the development of multi-skilled workforce in project management. The purpose of this paper is to investigate a multi-skill project scheduling problem (MSPSP), which combines project scheduling and multi-skill personnel assignment. The distinct features of skill evolution and cooperation effectiveness are considered in the problem to maximize the total project effectiveness and skill development simultaneously.
Design/methodology/approach
The Bi-objective non-linear integer programming (LIP) models are formulated for the problem using three types of skill development objective function: number of experts, total skill increment and “bottleneck” skill increment. Non-linear models are then linearized through several linearization techniques, and the ε-constraint method is used to convert the bi-objective models into single-objective models.
Findings
A construction project case is used to validate the proposed models. In comparison with models that do not consider skill evolution and cooperation effectiveness, the models proposed in this paper offer more realistic solutions and show better performance with regard to both project effectiveness and skill development.
Originality/value
This research extends the current MSPSP by considering skill evolution based on the “learning effect” as well as the influence of cooperation in an activity-based team, which are common phenomena in practice but seldom studied. LIP models formulated in this paper can be solved by any off-the-shelf optimization solver, such as CPLEX. Besides, the proposed LIP models can offer better project scheduling and personnel assignment plan, which would be of immense practical value in project management applications.