Mohamad Mahmoudi, Alaa Elwany, Aref Yadollahi, Scott M. Thompson, Linkan Bian and Nima Shamsaei
The purpose of this paper is to understand the effect of four different factors: building orientation, heat treatment (solution annealing and aging), thermal history and process…
Abstract
Purpose
The purpose of this paper is to understand the effect of four different factors: building orientation, heat treatment (solution annealing and aging), thermal history and process parameters on the mechanical properties and microstructural features of 17-4 precipitation hardening (PH) stainless steel (SS) parts produced using selective laser melting (SLM).
Design/methodology/approach
Various sets of test samples were built on a ProX 100™ SLM system under argon environment. Characterization studies were conducted using mechanical tensile and compression test, microhardness test, optical microscopy, X-ray diffraction and scanning electron microscopy.
Findings
Results indicate that building orientation has a direct effect on the mechanical properties of SLM parts, as vertically built samples exhibit lower yield and tensile strengths and elongation to failure. Post-SLM heat treatment proved to have positive effects on part strength and hardness, but it resulted in reduced ductility. Longer inter-layer time intervals between the melting of successive layers allow for higher austenite content because of lower cooling rates, thus decreasing material hardness. On the other hand, tensile properties such as elongation to failure, yield strength and tensile strength were not significantly affected by the change in inter-layer time intervals. Similar to other AM processes, SLM process parameters were shown to be instrumental in achieving desirable part properties. It is shown that without careful setting of process parameters, parts with defects (porosity and unmelted powder particles) can be produced.
Originality/value
Although the manufacturing of 17-4 PH SS using SLM has been investigated in the literature, the paper provides the first comprehensive study on the effect of different factors on mechanical properties and microstructure of SLM 17-4 PH. Optimizing process parameters and using heat treatment are shown to improve the properties of the part.
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Brian Torries, Amanda J. Sterling, Nima Shamsaei, Scott M. Thompson and Steve R. Daniewicz
The purpose of this study is to calibrate a microstructure-based fatigue model for its use in predicting fatigue life of additively manufactured (AM) Ti-6Al-4V. Fatigue models…
Abstract
Purpose
The purpose of this study is to calibrate a microstructure-based fatigue model for its use in predicting fatigue life of additively manufactured (AM) Ti-6Al-4V. Fatigue models that are capable of better predicting the fatigue behavior of AM metals is required to further the adoption of such metals by various industries. The trustworthiness of AM metallic material is not well characterized, and fatigue models that consider unique microstructure and porosity inherent to AM parts are needed.
Design/methodology/approach
Various Ti-6Al-4V samples were additively manufactured using Laser Engineered Net Shaping (LENS), a direct laser deposition method. The porosity within the LENS samples, as well as their subsequent heat treatment, was varied to determine the effects of microstructure and defects on fatigue life. The as-built and heat-treated LENS samples, together with wrought Ti-6Al-4V samples, underwent fatigue testing and microstructure and fractographic inspection. The collected microstructure/defect statistics were used for calibrating a microstructure-sensitive fatigue model.
Findings
Fatigue lives of the LENS Ti-6Al-4V samples were found to be consistently less than those of the wrought Ti-6Al-4V samples, and this is attributed to the presence of pores/defects within the LENS material. Results further indicate that LENS Ti-6Al-4V fatigue lives, as predicted by the used microstructure-sensitive fatigue model, are in close agreement with experimental results. The used model could predict upper and lower prediction bounds based on defect statistics. All the fatigue data were found to be within the bounds predicted by the microstructure-sensitive fatigue model.
Research limitations/implications
To further test the utility of microstructure-sensitive fatigue models for predicting fatigue life of AM samples, future studies on additional material types, additive manufacturing processes and heat treatments should be conducted.
Originality/value
This study shows the utility of a microstructure-sensitive fatigue model for use in predicting the fatigue life of LENS Ti-6Al-4V with various levels of porosity and while in a heat-treated condition.
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Abstract
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Jonathan M Scott, Andy Penaluna and John L Thompson
The purpose of this paper is to conduct a critical appraisal of how experiential approaches can more effectively enhance the achievement of desired learning outcomes in…
Abstract
Purpose
The purpose of this paper is to conduct a critical appraisal of how experiential approaches can more effectively enhance the achievement of desired learning outcomes in entrepreneurship education. In particular, the authors critique whether actual learning outcomes can be profitably used to measure effectiveness; and consider how student performance can be evaluated through the twin lenses of implementation or innovation.
Design/methodology/approach
The authors undertook a review of both traditional and experiential approaches to entrepreneurship education. In addition to comparing these approaches, the authors critiqued a number of “taken for granted” assumptions regarding the effectiveness of experiential approaches to entrepreneurship education and made recommendations.
Findings
Although there is a large body of research on experiential approaches towards entrepreneurship education, the authors know little about how these approaches contribute towards the effective achievement of desired learning outcomes. Whilst many authors claim that such approaches are effective, such assertions are not supported by sufficient robust evidence. Hence the authors need to establish more effective student performance evaluation metrics. In particular: first, whether actual learning outcomes are appropriate measures of effectiveness; and second, the authors should evaluate student performance through the lenses of the two “Is” – implementation or innovation.
Practical implications
Whether actual learning outcomes are used as a measure of effectiveness at all needs to be critiqued further. Implementation involves doing things that are determined by others and matching against their expectations, whereas innovation comprises producing multiple and varied solutions that respond to change and often surprise.
Originality/value
Through revisiting the discussions on the art and the science of entrepreneurship education, this paper represents an initial critical attempt – as part of an ongoing study – to fill a gap in entrepreneurship education research. The paper, therefore, has significant value for students, entrepreneurship educators and policy-makers.
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Tjaša Štrukelj, Dejana Zlatanović, Jelena Nikolić and Simona Sternad Zabukovšek
The purpose of this paper is to prove that it is possible and necessary that higher education institutions develop appropriate competencies of students during the learning process…
Abstract
Purpose
The purpose of this paper is to prove that it is possible and necessary that higher education institutions develop appropriate competencies of students during the learning process as required by the practice if teachers use the systemic approach and cybernetics knowledge. The authors especially research the importance of competence entrepreneurship and how to stimulate entrepreneurship by developing competencies of creativity, teamwork and communication.
Design/methodology/approach
Based on systems theory, transversal competencies entrepreneurship, creativity, teamwork and communication, as well as their interdependence, were requisitely holistic selected. In the selection of diverse contemporary learning methods, the authors started from an action research approach that implies learning by doing, i.e. participation of students. With the use of statistical methods, the authors showed that a cyber-systemic requisite holistic learning action approach based on interdependence of teacher and students learning process results in innovation of researched transversal competencies.
Findings
Based on two quantitative and qualitative researches of 96 students’ competencies, the authors found out that when using contemporary learning methods, the desired results can be achieved. In described learning process everyone involved gained: both the teacher and the students.
Research limitations/implications
The survey does not include verifying the usefulness of developed competencies in practice. Also, the study only covers the findings of the research study of one academic year.
Practical implications
The research is important for the practice of higher education, as it demonstrates that the teacher is with a targeted focus on the selected viewpoints able to effectively improve students’ competencies.
Social implications
If higher education’s institutions take a strategic decision to target improvement of the transversal competencies of students, they will be easier and faster to employ, and practice will get more relevant employees. The economy will be more efficient and effective.
Originality/value
According to the authors’ knowledge, no research measures the development of selected transversal competencies using the contemporary learning methods, based on cyber-systemic learning action approach. The authors found out that the methods used have influenced the final results, which show that all measured students’ transversal competencies have improved.
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Purpose – The integration of librarians and technologists to deliver information services represents a new and costly organizational challenge for many library administrators. To…
Abstract
Purpose – The integration of librarians and technologists to deliver information services represents a new and costly organizational challenge for many library administrators. To understand how to control the costs of integration, this study uses structural contingency theory to study the coordination of librarians and technologists within the information commons.
Design/methodology/approach – This study tests the structural contingency theory expectation that an organization will achieve higher levels of performance when there is a positive relationship between the degree of workflow interdependence and the complexity of coordinative structures necessary to integrate these workflows. This expectation was tested by (a) identifying and collecting a sample of information common; (b) developing and validating survey instruments to test the proposition; and (c) quantitatively analyzing the data to test the proposed contingency theory relationship.
Findings – The contingency theory expectations were confirmed by finding both a positive relationship between coordination and interdependence and a positive relationship between perceptions of performance and degree of congruency between interdependence and coordination.
Limitations – The findings of this study are limited to both the context of an information common and the structures tested. Future research should seek to both broaden the context in which these findings are applicable, and test additional structural relationships as proposed by contingency theory
Practical implications – This study contributes to the library profession in a number of ways. First, it suggests that managers can improve IC performance by matching coordination structures to the degree of interdependence. For instance, when librarians and technologists are strictly co-located, managers should coordinate workflows using less resource-intensive policies rather than meetings. Second, the instruments developed in this study will improve the library manager's ability to measure and report unit interdependence and coordination in a valid and reliable manner. Lastly, it also contributes to the study of structural contingency theory by presenting one of the first empirical confirmations of a positive relationship between interdependence and coordination.
Originality/value – This study represents one of the first empirical confirmations of the structural contingency theory expectations of both a positive relationship between workflow interdependence and coordination, and a positive relationship between performance and coordination's fit to workflow interdependence. These findings are of value to both organizational theorists and to administrators of information commons.
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Noel Scott, Brent Moyle, Ana Cláudia Campos, Liubov Skavronskaya and Biqiang Liu
Eric J. Arnould and Craig J. Thompson
This paper reflects on the development of Consumer Culture Theory, both as a field of research and as an institutional classification, since the publication of Arnould and Thompson…
Abstract
Purpose
This paper reflects on the development of Consumer Culture Theory, both as a field of research and as an institutional classification, since the publication of Arnould and Thompson (2005).
Methodology/approach
This paper takes a conceptual/historical orientation that is based upon the authors’ experiences over the course of the 10-year CCT initiative (including numerous conversations with fellow CCT colleagues).
Findings
The authors first discuss key benchmarks in the development of the CCT community as an organization. Next, the authors highlight key intellectual trends in CCT research that have arisen since the publication of their 2005 review and discuss their implications for the future trajectories of CCT research.
Originality/value
The paper by Arnould and Thompson (2005) has proven to be influential in terms of systematizing and placing a widely accepted disciplinary brand upon an extensive body of culturally oriented consumer research. The CCT designation has also provided an important impetus for institution building. The 10-year anniversary of this article (and not incidentally the CCT conference from which the papers in this volume hail) provides a unique opportunity for the authors to comment upon the broader ramifications of their original proposals.