Randall W. Eberts, Kevin Hollenbeck and Joe A. Stone
What evidence is available to assess the concrete effects of teacher unions on public schools and to provide a basis for the most reliable conclusions? Other reviews of teacher…
Abstract
What evidence is available to assess the concrete effects of teacher unions on public schools and to provide a basis for the most reliable conclusions? Other reviews of teacher unions often ask related but different questions that emphasize the institutional context, evolution, and operation of collective bargaining in public schools. Two prominent examples of this genre are Teacher Unions in Schools (Johnson, 1984) and The Changing Idea of a Teachers’ Union (Kerchner & Mitchell, 1988). Other contributions to the present volume offer related perspectives.
P. Regenfuss, L. Hartwig, S. Klötzer, R. Ebert, Th. Brabant, T. Petsch and H. Exner
Examples are given for the technical applicability of a novel development of selective laser sintering called “laser micro sintering”.
Abstract
Purpose
Examples are given for the technical applicability of a novel development of selective laser sintering called “laser micro sintering”.
Design/methodology/approach
Together with a specific method to produce powder layers, the controlled application of pulsed radiation for the processing of sub‐μm grained metal powders was exploited to produce micro‐tools with a heretofore unattained structural resolution.
Findings
High resolution micro bodies are displayed. Instruments could be generated which proved to fulfil their designation as grip bits for micro manipulators. The micro‐bodies can be generated detachably from or firmly fixed to the construction substrate. The material of the generated bodies withstands the traction forces when used as an injection mold for polymer casts.
Research limitations/implications
Densities and structural resolutions can still be improved especially with a newly updated version of the equipment. Laser micro sintering of materials, other than metal (e.g. ceramics), has still to be developed. The introduction of the equipment and the technique into the market is on its way.
Practical implications
Micro‐tools can be generated with an overall structural resolution of 30 μm and with all the advantages of a freedom technique.
Originality/value
The paper informs the technical community on a new novel modification of the freeform technique selective laser sintering, demonstrating the solution of some problems that have hampered the progress of metal laser into resolution ranges below 100 μm. It also supplies evidence for the technical applicability.
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P. Regenfuss, A. Streek, L. Hartwig, S. Klötzer, Th. Brabant, M. Horn, R. Ebert and H. Exner
The purpose of the paper is the elucidation of certain mechanisms of laser material processing in general and laser micro sintering in particular. One major intention is to…
Abstract
Purpose
The purpose of the paper is the elucidation of certain mechanisms of laser material processing in general and laser micro sintering in particular. One major intention is to emphasize the synergism of the various effects of q‐switched laser pulses upon metal and ceramic powder material and to point out the non‐equilibrium character of reaction steps.
Design/methodology/approach
Recent results and observations, obtained in development of “laser micro sintering,” are surveyed and analyzed. By breaking down the overall process into relevant steps and considering their possible kinetics, an approach is made towards interpreting specific phenomena of laser micro sintering. Thermodynamics upon heating of the material as well as its photo‐electronic response to the incident radiation are considered.
Findings
The findings corroborate a model whereby short pulses of high intensity provide non‐equilibrium pressure conditions at the location of incidence, that allow for the melting of metal powder with an almost immediate expansion of a plasma and/or vapor bulb. Thereby the molten material is condensed and propelled towards the substrate. A final boiling eruption after each pulse is the reason for the morphology of the laser micro‐sintered surfaces and can prevent oxidation when the process is conducted under normal atmosphere. In sintering of ceramics, the short pulsed and intensive radiation increases the chance to excite the material even with photon energies below the bandgap value and it lowers the risk of running into a destructive avalanche.
Research limitations/implications
Owing to the stochastic character of the respective sintering event, that is initiated by each individual pulse, the gathered data are not suitable yet for the formulation of an exact quantitative function between sintering behavior and laser parameters.
Practical implications
The qualitative findings yield a good rule of thumb for the choice of parameters in laser sintering on a micrometer scale and the model is conducive for advanced interpretation of other phenomena in laser material processing besides sintering.
Originality/value
The kinetics and thermodynamics of laser sintering with q‐switched pulses are approached by a qualitative explanation. The heterogeneous and non‐equilibrium character of the processes is taken into account; this character is often neglected by researchers in the area.
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Linda Ke, Haihong Zhu, Jie Yin and Xinbing Wang
– The purpose of this paper is to report the influence of the peak laser power on laser micro sintering 4-μm nickel powder using Q-switched 1064-nm Nd:YAG laser.
Abstract
Purpose
The purpose of this paper is to report the influence of the peak laser power on laser micro sintering 4-μm nickel powder using Q-switched 1064-nm Nd:YAG laser.
Design/methodology/approach
Experimental study has been performed. Nickel powder with grain size of 4 μm has been utilized. A Q-switching duration of 20-25 μs and rate of 20-40 kHz have been used.
Findings
The peak power intensity is so high that the metal particles and molten pool are blown away, leading to laser micro sintering not being successfully proceeded. The scanning line obtained by continuous-wave (CW) laser looks like a rod owing to balling effect. Using a suitable peak power intensity, a good-shaped sintering line can be obtained because the plasma can protect the molten metal from oxidation, and improve the wettability of the system. In addition, the plasma flattening effect may also contribute to the form of the good-shaped sintering line in pulsed laser sintering regime.
Originality/value
The role of plasma induced by pulsed laser with high peak power intensity has been found during pulsed laser sintering under an ambient environment.
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– The purpose of this paper is to examine the managerial role in the practices of corporate social responsibility (CSR) in developing economies.
Abstract
Purpose
The purpose of this paper is to examine the managerial role in the practices of corporate social responsibility (CSR) in developing economies.
Design/methodology/approach
The paper takes the form of an empirical analysis of employees' opinions based on a quantitative survey of 100 middle and senior level managers from four organisations chosen from relatively high impact industry sectors.
Findings
Managerial role in the practice of CSR is limited and ineffective in Ghana. Difficulties of effective CSR implementation mainly stem from leadership weak spots in the form of mismanagement and corruption, lack of leadership commitment and unwillingness to allocate monies due for CSR activities. Organisations can do better in the practice of CSR if management's attitude to CSR, corruption, and work behaviors are positive.
Practical implications
The paper provides valuable information on managerial activities with regards to organisational CSR, and how these can be improved.
Originality/value
Empirical literature on CSR in developing countries is limited. This paper identifies the roles that management and organisational leadership can play in the practice of CSR in developing countries. The paper proposes a universal approach which aims to address the need for adequate and effective enforcement of CSR.
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This paper aims to study the state of the art of corporate social responsibility (CSR) governance and operational structure within the most sustainable companies to arrive at a…
Abstract
Purpose
This paper aims to study the state of the art of corporate social responsibility (CSR) governance and operational structure within the most sustainable companies to arrive at a typology of CSR organization. Whether companies consider corporate social responsibility (CSR) a strategic management task is mirrored in the department and governance structure of CSR.
Design/methodology/approach
By conducting a web content analysis, the authors apply a “best practice” approach to examine the vertical and horizontal organization of CSR within the “most sustainable companies worldwide” (Robeco SAM, 2013).
Findings
The results show that most corporations have in place governance structures for CSR that organize it horizontally in stand-alone departments. Three types of CSR organization best practice emerged: the single-headed, two-headed and infused types.
Practical implications
The paper indicates three different ways that companies can organize CSR internally. The authors discuss the feasibility of such organization for large and small companies and their day-to-day business.
Originality/value
The paper addresses the under-researched area of vertical and horizontal CSR organization at the micro level. The authors analyze the state of the art of organizational and governance structures of CSR in the most sustainable companies and deduce three types of CSR governance and operational architecture.
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This article illustrates the transformational nature of servant leadership and its capacity to empower and develop others. In it, I recount my close relationship with a high…
Abstract
Purpose
This article illustrates the transformational nature of servant leadership and its capacity to empower and develop others. In it, I recount my close relationship with a high school mentor who embodied the key tenants of Greenleaf’s (1970) servant leadership philosophy. I also advocate for others to provide mentorship and support in a similar fashion.
Design/methodology/approach
This Origins contribution was constructed as a reflective narrative in response to a mentorship experience earlier in my life.
Findings
A mentorship experience from my youth profoundly shaped my approach to leadership and teamwork that I still embrace to this day. Readers are asked to consider the power of servant leadership in their own lives.
Originality/value
Students of leadership can utilize this reflective essay as a touchstone for further classroom discussion.
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Examines marketing techniques used by British non‐profit organisations. Defines public sector and voluntary sector non‐profit organisation. Outlines the difficulties encountered…
Abstract
Examines marketing techniques used by British non‐profit organisations. Defines public sector and voluntary sector non‐profit organisation. Outlines the difficulties encountered in defining the marketing process in non‐profit organisations compared with normal business operations. Highlights four main areas of marketing for non‐profit organisations – research, promotion, pricing and distribution. Concludes that the non‐profit sector includes a number of organisations where ownership, structure and objectives do not correspond to the traditional model of business organisations. Affirms that British authors should view these dissimilarities as an opportunity to develop the marketing concept, marketing and marketing management in a much wider context than that of business marketing.