Product and process innovations by means of rapid technologies

Published ArticleOver the past few years, methods of layered manufacturing (LM) have advanced substantially to the point where they now provide vital strategic benefits to various organisations. One area of application where LM technologies have begun to reach a critical mass is in the development and production of high-performance tooling in different forming processes. With these tooling capabilities now available, the next challenge becomes the development of optimal process chains to minimise lead times and production costs, while still ensuring high quality of castings. The relevant issues that influence where a break-even point will be between different process chains and thereby also the point of selection between such optimal process chains according to different situations include among others: the size of production runs, part size and complexity, and the cast materials involved. This paper reflects some of the experiences gained from an investigation towards developing a set of generic rules (guidelines) for the design of optimal process chains for sand casting prototypes of automotive components using LM methods, and more specifically the 3D Printing process

Direct neutron capture cross sections of 62Ni in the s-process energy range

Direct neutron capture on 62Ni is calculated in the DWBA and the cross sections in the energy range relevant for s-process nucleosynthesis are given. It is confirmed that the thermal value of the capture cross section contains a subthreshold resonance contribution. Contrary to previous investigations it is found that the capture at higher energies is dominated by p-waves, thus leading to a considerably increased cross section at s-process energies and a modified energy dependence.Comment: 10 pages, 1 figure, corrected typos in Eq. 6 and subsequent paragrap

Engaged but exhausted: Work-related wellbeing profiles of South African employees

Organizations and colleagues alike benefit from dedicated employees who are immersed in their work and energetically pursue their tasks. Unfortunately, this may come at a price for employees who may burn out. Organizations are, therefore, confronted with a responsibility to assist employees in striking a balance between eagerly engaging in their tasks and taking care of their wellbeing. Before designing and implementing interventions, it is valuable to identify how engagement and burnout components cluster within individuals and whether these different combinations have different implications for employees. The study aimed to explore whether burnout and work engagement combine within individuals to form different burnout-engagement profiles. The study also aimed to examine the implications of different profiles for employees’ psychological distress, affective commitment, and turnover intention. Among 1048 South African employees, latent profile analysis highlighted five distinct burnout-engagement profiles: Burned-out, Risky, Moderately balanced, Stars, and Workaholics. The Burned-out reported higher levels of psychological distress than the Risky. Still, both reported higher levels than the Moderately balanced, who also reported higher levels of psychological distress than the Stars. The Burned out and the Workaholics reported equal levels of psychological distress. The Stars reported the highest levels of affective commitment, followed by the Workaholics, the Moderately balanced, and the Risky, with the lowest levels reported by the Burned-out. The Burned-out reported the highest levels of turnover intention, followed by the Risky, the Workaholics, and the Moderately balanced, with the lowest levels reported by the Stars. Limitations, recommendations for future research and practical implications are discussed

The effect of coupling circuits on impulsive noise in power line communication

Abstract: Most researchers in the Power Line Communications (PLC) field have adopted the practice of using idealized impulse noise models directly at the input of the demodulator, as is widely done in simulations. The effect of the coupling circuit on the impulse noise tend to be ignored. However, coupling circuits produce transients. This paper focuses on investigating the effect of the coupling circuit on the impulse noise. Experimental measurements are used to determine the effect of the coupling circuit. An equivalent circuit of the coupling circuit is developed and further simulations are conducted to gain in-depth knowledge on how the impulse noise is affected by the coupling circuit. A literature survey suggests that this topic has not been studied yet

Psychometric properties of the Flourishing Scale for South African first-year students

This study focused on a positive construct of well-being, namely flourishing. In a multicultural and diverse country such as South Africa, it is a legal requirement to provide evidence that measures of psychological constructs, like flourishing, are fair, unbiased, and equivalent for diverse groups in the country. The aim was to test the psychometric properties of the Flourishing Scale, a purpose-made scale that measures positive functioning across various areas of life. This study tested the factorial validity, item bias, measurement invariance and reliability of the Flourishing Scale in a sample of 1088 South African first-year university students. A unidimensional structure was confirmed. Although three items showed statistically significant uniform and total bias for language and campus groups, the magnitude and practical impact were negligible. No evidence of bias across gender groups was found. Configural, metric and partial scalar invariance were established for language and campus groups. Full measurement invariance was established across gender groups. Cronbach’s alpha coefficient was 0.91, indicating high reliability. The study provided promising results for using the Flourishing Scale among South African university students to measure flourishing as an aspect of well-being. Contribution: This study contributes to the field of student well-being in South Africa. No studies could be found that test for item bias or measurement invariance of the Flourishing Scale, specifically for South African first-year students. This study is the first to test these psychometric properties of a Flourishing Scale in a multicultural setting for students from different languages

Instability of confined water films between elastic surfaces

We investigated the dynamics of nanometer thin water films at controlled ambient humidity adsorbed onto two atomically smooth mica sheets upon rapidly bringing the surfaces into contact. Using a surface forces apparatus (SFA) in imaging mode, we found that the water films break up into a distribution of drops with a typical thickness of a few nanometers and a characteristic lateral size and spacing of several micrometers. Whereas the characteristic length is found to be independent of the ambient humidity, the characteristic time of the breakup decreases from 1 to 0.01 s with increasing humidity. The existence of characteristic length and time scales shows that this breakup is controlled by an instability rather than a conventional nucleation and growth mechanism for SFA experiments. These findings cannot be explained by a dispersion-driven instability mechanism. In contrast, a model involving the elastic energies for the deformation of both the mica sheets and the underlying glue layer correctly reproduces the scaling of the characteristic length and time with humidity