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Article
Publication date: 6 July 2020

Johanna J. Schwartz, Joshua Hamel, Thomas Ekstrom, Leticia Ndagang and Andrew J. Boydston

Additive manufacturing (AM) methods such as material extrusion (ME) are becoming widely used by engineers, designers and hobbyists alike for a wide variety of applications…

388

Abstract

Purpose

Additive manufacturing (AM) methods such as material extrusion (ME) are becoming widely used by engineers, designers and hobbyists alike for a wide variety of applications. Successfully manufacturing objects using ME three-dimensional printers can often require numerous iterations to attain predictable performance because the exact mechanical behavior of parts fabricated via additive processes are difficult to predict. One of that factors that contributes to this difficulty is the wide variety of ME feed stock materials currently available in the marketplace. These build materials are often sold based on their base polymer material such as acrylonitrile butadiene styrene or polylactic acid (PLA), but are produced by numerous different commercial suppliers in a wide variety of colors using typically undisclosed additive feed stocks and base polymer formulations. This paper aims to present the results from an experimental study concerned with quantifying how these sources of polymer variability can affect the mechanical behavior of three-dimensional printed objects. Specifically, the set of experiments conducted in this study focused on following: several different colors of PLA filament from a single commercial supplier to explore the effect of color additives and three filaments of the same color but produced by three different suppliers to account for potential variations in polymer formulation.

Design/methodology/approach

A set of five common mechanical and material characterization tests were performed on 11 commercially available PLA filaments in an effort to gain insight into the variations in mechanical response that stem from variances in filament manufacturer, feed stock polymer, additives and processing. Three black PLA filaments were purchased from three different commercial suppliers to consider the variations introduced by use of different feed stock polymers and filament processing by different manufacturers. An additional eight PLA filaments in varying colors were purchased from one of the three suppliers to focus on how color additives lead to property variations. Some tests were performed on unprocessed filament samples, while others were performed on objects three-dimensional printed from the various filaments. This study looked specifically at four mechanical properties (Young’s modulus, storage modulus, yield strength and toughness) as a function of numerous material properties (e.g. additive loading, molecular weight, molecular weight dispersity, enthalpy of melting and crystallinity).

Findings

For the 11 filaments tested the following mean values and standard deviations were observed for the material properties considered: pa = 1.3 ± 0.9% (percent additives), Mw = 98.6 ± 16.4 kDa (molecular weight), Ð = 1.33 ± 0.1 (molecular weight dispersity), Hm = 37.4 ± 7.2 J/g (enthalpy of melting) and = 19.6 ± 2.1% (crystallinity). The corresponding mean values and standard deviations for the resulting mechanical behaviors were: E = 2,790 ± 145 MPa (Young’s modulus), E’ = 1,050 ± 125 MPa (storage modulus), Sy = 49.6 ± 4.93 MPa (yield strength) and Ut = 1.87 ± 0.354 MJ/m^3 (toughness). These variations were observed in filaments that were all manufactured from the same base polymer (e.g. PLA) and are only different in terms of the additives used by the manufacturers to produce different colors or different three-dimensional printing performance. Unfortunately, while the observed variations were significant, no definitive strong correlations were found between these observed variations in the mechanical behavior of the filaments studied and the considered material properties.

Research limitations/implications

These variations in mechanical behavior and material properties could not be ascribed to any specific factor, but rather show that the mechanical of three-dimensional printed parts are potentially affected by variations in base polymer properties, additive usage and filament processing choices in complex ways that can be difficult to predict.

Practical implications

These results emphasize the need to take processing and thereby even filament color, into account when using ME printers, they emphasize the need for designers to use AM with caution when the mechanical behavior of a printed part is critical and they highlight the need for continued research in this important area. While all filaments used were marked as PLA, the feedstock materials, additives and processing conditions created significant differences in the mechanical behavior of the printed objects evaluated, but these differences could not be accurately and reliably predicted as function of the observed material properties that were the focus of this study.

Originality/value

The testing methods used in the study can be used by engineers and creators alike to better analyze the material properties of their filament printed objects, to increase success in print and mechanical design. Furthermore, the results clearly show that as AM continues to evolve and grow as a manufacturing method, standardization of feedstock processing conditions and additives would enable more reliable and repeatable printed objects and would better assist designers in effectively implementing AM methods.

Details

Rapid Prototyping Journal, vol. 26 no. 7
Type: Research Article
ISSN: 1355-2546

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Available. Open Access. Open Access
Article
Publication date: 18 November 2024

Jannick Schneider, Clemens Striebing, Lydia Uhler, Johanna Marie Wührl, Simon Schmaus and Mathias Weber

This study investigates the differential effectiveness of leadership styles within the German Federal Police Office, focusing on how these styles interact with employees' personal…

190

Abstract

Purpose

This study investigates the differential effectiveness of leadership styles within the German Federal Police Office, focusing on how these styles interact with employees' personal values to influence organizational identification (OI). Thus, we investigate the augmentation hypothesis and explore the moderating effects of personal values on leadership effectiveness regarding OI.

Design/methodology/approach

Utilizing a quantitative cross-sectional design, the study analyzes responses from 1,816 police employees via the Multifactor Leadership Questionnaire and Portraits Value Questionnaire. Hierarchical regressions are used to analyze the hypothesized associations.

Findings

The results indicate that transformational leadership significantly enhances OI more than transactional or laissez-faire leadership. Moderating effects of personal values reveal complex interactions: while transformational leadership consistently predicts higher OI, transactional leadership’s effectiveness varies according to the employees' values such as Conformity and Tradition enhancing OI, Universalism and Benevolence diminishing it. These findings suggest that leadership effectiveness in policing is contingent on aligning leadership style with the personal values of the employees.

Originality/value

This research contributes to the understanding of how personal values modulate the impact of leadership styles on organizational outcomes within police organizations. It underscores the necessity for police leaders to consider the value profiles of their employees to optimize OI and effectiveness. The study is among the first to systematically explore these dynamics within a law enforcement context, providing empirical evidence to inform targeted leadership development and policy-making in policing.

Details

Policing: An International Journal, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 1363-951X

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Publication date: 2 November 2009

Peter Bonsall

The increasing prominence of environmental sustainability as an objective of transport policy, and in people's thinking about their travel-related decisions, brings new challenges…

Abstract

The increasing prominence of environmental sustainability as an objective of transport policy, and in people's thinking about their travel-related decisions, brings new challenges for data collection because, uniquely in the transport sector, it brings three issues to the fore: firstly, the difficulties associated with gathering data and opinions on a topic which is socially and morally charged; secondly, the fact that the resulting adjustments to behaviour may be in dimensions (such as choice of vehicle characteristics and mode choice for infrequent trips) which are not traditionally covered very fully in travel surveys; and thirdly, the likelihood that any change in behaviour may emerge only slowly over an extended period of time (as and when the opportunity arises for the individuals' behaviour to be adjusted to fit their aspirations).

It is argued that, because the topic is socially charged, data on sustainable travel behaviour is particularly prone to social desirability bias and other related biases. The nature and implications of these biases are addressed and it is concluded that individuals will tend to exaggerate the likelihood of behavioural change in response to sustainability concerns and policy initiatives. Methods, which might be used to study the emergence of sustainable patterns of behaviour in general, and responses to sustainability orientated policy initiatives in particular, are discussed and attention is given to ways of minimising bias in the data.

Details

Transport Survey Methods
Type: Book
ISBN: 978-1-84-855844-1

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Book part
Publication date: 2 March 2017

Abstract

Details

The Imagination Gap
Type: Book
ISBN: 978-1-78714-207-7

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Book part
Publication date: 6 July 2021

Soon Seok Park

Prodemocracy protest in South Korea in the 1980s can be described in terms of two waves of sustained activism between 1979 and 1987. One wave was brutally repressed in the Gwangju…

Abstract

Prodemocracy protest in South Korea in the 1980s can be described in terms of two waves of sustained activism between 1979 and 1987. One wave was brutally repressed in the Gwangju Uprising of May 1980, while the other succeeded in bringing in a transition to democracy in June 1987. How did activists recover from the repression in the first wave, and how did they create a viable movement in the second wave? This work focuses on the role of memory work about the Gwangju Uprising in the mobilization of the prodemocracy movement. Drawing on a wide assortment of documents collected from various archives in South Korea, the author demonstrates how memory work contributed to the movement dynamics. Cognitively, memory work radicalized movement participants such that they became completely disillusioned with the legitimacy of state power. Emotionally, memory work triggered a moral shock among recruits that motivated them to take the high risks associated with activism. Relationally, memory work provided a bonding experience for activists within a network. The findings also show a process through which memory work becomes a powerful social force: emergence of a challenger, proliferation of an alternative narrative, and then a full-blown contention between the state and a challenger. The process also means changes of the status of memory in terms of ownership, salience, and valence.

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Article
Publication date: 19 April 2013

Katarina Hellén and Johanna Gummerus

Service scholars have questioned the usefulness of the concept of tangibility/intangibility as a characteristic of services for two reasons: first, it is ambiguous and does not…

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Abstract

Purpose

Service scholars have questioned the usefulness of the concept of tangibility/intangibility as a characteristic of services for two reasons: first, it is ambiguous and does not differentiate between services and goods; and second, because all offerings, despite their characteristics, render service to customers. Consequently, scholars have suggested discarding the concept altogether. The purpose of this paper is to subject the concept to critical evaluation and argue that tangibility/intangibility is useful, because it influences consumers' experiences with offerings. In this paper, the authors argue that it is necessary to re‐conceptualise tangibility/intangibility to overcome the previous critique.

Design/methodology/approach

The authors draw upon empirical research from the service marketing and psychology literature in order to advance knowledge on the nature of tangibility/intangibility and its influence on the formation of consumer experiences.

Findings

It is proposed that tangibility/intangibility should be investigated from a consumer perspective, rather than an inherent characteristic in offerings. Also, it is shown that the concept is relevant for understanding consumer experience formation at different stages of the purchase process.

Originality/value

The paper provides propositions on the conceptualization of tangibility/intangibility and its relationship with pre‐, ongoing use and post‐purchase consumer experiences. The authors call for caution in dismissing tangibility/intangibility as a concept in the service marketing literature.

Details

Journal of Service Management, vol. 24 no. 2
Type: Research Article
ISSN: 1757-5818

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Article
Publication date: 14 May 2018

Dominik Emanuel Froehlich, Mingyang Liu and Beatrice Isabella Johanna Maria Van der Heijden

Employability and its components have received a lot of attention from scholars and practitioners. However, little is known about the interrelations between these different…

1177

Abstract

Purpose

Employability and its components have received a lot of attention from scholars and practitioners. However, little is known about the interrelations between these different components of employability and how employees progress within their employability trajectories. Therefore, a model of such progression was constructed and tested using Van der Heijde and Van der Heijden’s (2006) employability measurement instrument. The paper aims to discuss these issues.

Design/methodology/approach

The propositions were tested empirically by applying a Rasch model using a sample of 167 Austrian business consultants.

Findings

The findings lend some support for the hypothesized progression model of employability. Specifically, the items measuring occupational expertise are largely located in the group of items that were relatively likely to be endorsed. Also, the items of personal flexibility and anticipation and optimization were, in general, less likely to be endorsed than the items of occupational expertise.

Research limitations/implications

The major thrust of this paper is a theoretical one. However, the empirical demonstration tentatively supports the proposed model, which implies that further, more robust longitudinal research in this direction may be a worthwhile endeavor.

Practical implications

By understanding which competences are important at which stage or across which stages of an individual’s career, career advisors and human resource management professionals can give more targeted advice concerning career management practices.

Originality/value

The present study contributes to the literature by investigating how employees may make progress within their employability trajectories.

Details

Career Development International, vol. 23 no. 2
Type: Research Article
ISSN: 1362-0436

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Book part
Publication date: 6 July 2021

Gabriela González Vaillant and Fernanda Page Poma

This paper analyzes the relationship between the Chilean student movement and state force action during the period 2000–2012, placing specific attention on three waves of student…

Abstract

This paper analyzes the relationship between the Chilean student movement and state force action during the period 2000–2012, placing specific attention on three waves of student contention that took place at the turn of the century. During the decade under study, the Chilean students became more contentious, they broadened their demands beyond specific grievances to encompass a critique to the education system as a whole, their alliance system grew (gaining from these denser networks of collaboration more resources to mobilize), and they managed to win public opinion on their side. However, the relationship with state forces has not been static across time, and both students and state forces have experienced changes in how they interact with each other. The results of this paper are based on a mixed method approach that drew on a quantitative database of student contention in Chile (n = 491 student events) and 15 in-depth interviews with leader activists from the most salient recent Chilean student movements of three periods under study, in addition to some key informants. The findings confirm that when student protests target the government, when they use disruptive strategies that affect the status-quo, and when they mobilize alongside other challenging actors, they are more likely to be met with direct repression by authorities. The research shows that there is a “dialect of repression” at play by which state forces' direct repression of protest can be two-fold: on the one hand, it gives students visibility in the public opinion, but on the other, it can be negative for ushering support if the media and authorities are successful in portraying them as violent or a threat to public order. In this sense, the figure of the “encapuchado,” students who disguise their identity and purposefully seek confrontation with authorities during mobilizations is problematized by the movement itself. How to win public opinion and use that visibility in their favor is related to decision-making mechanisms that the movement puts at play but also to the calculations done on the part of the government and security forces about the leverage of the movement.

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Four Dead in Ohio
Type: Book
ISBN: 978-1-80071-807-4

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Article
Publication date: 8 March 2024

Jennifer Kunz, Johanna Oltmann and Felix Weinhart

The present paper aims to focus on the role which German controllers play so far in the process of sustainable transformation in for-profit organizations, the current obstacles to…

416

Abstract

Purpose

The present paper aims to focus on the role which German controllers play so far in the process of sustainable transformation in for-profit organizations, the current obstacles to a wider engagement here and ways to overcome these obstacles.

Design/methodology/approach

The analysis combines two qualitative study designs. Empirical data is generated via a job advertisement analysis and an explorative survey with 107 subjects from management accounting/controlling and sustainability management. The generated data is interpreted against the background of the theory of institutional logics and Abbott’s (1988) theory of professional jurisdiction.

Findings

We find that controllers are in a state of tension. On the one hand, the pressure to integrate sustainability into companies is increasing. On the other hand, they seem to be rather reluctant to get involved. The institutional logics that shape their profession play an important role here, as does an unclear relationship with the sustainability department, which has its own claims here. Based on these observations, we identify the core obstacles to the transformation of the controllers’ profession and discuss solutions which can guide the transformation of this profession.

Originality/value

The present paper provides insights from a unique combination of different quantitative study designs and different perspectives on the possible role that controllers can play in advancing sustainable transformation in companies.

Details

Accounting, Auditing & Accountability Journal, vol. 38 no. 1
Type: Research Article
ISSN: 0951-3574

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Book part
Publication date: 12 December 2024

Johanna Sofia Adolfsson, Arve Hansen and Ulrikke Wethal

How to change consumption patterns remains one of the most wicked global sustainability challenges, and it is increasingly acknowledged that such wicked problems require…

Abstract

How to change consumption patterns remains one of the most wicked global sustainability challenges, and it is increasingly acknowledged that such wicked problems require interdisciplinary solutions. In this chapter, we ask what can be learnt from contrasting two approaches to sustainable consumption that only to a very limited extent interact. First, psychological approaches to consumption have been immensely influential concerning individual behavioural change, particularly through their theorisations of ‘nudge’ and ‘choice architecture’. Second, social practice theories (SPTs) have obtained a dominant position in sociocultural approaches to consumption, focusing on how bodily, social and material elements combine into taken-for-granted daily routines that make up shared patterns of (unsustainable) social life. Interestingly, despite the theoretical approaches' different ontologies and analytical loci, nudge theory and practice theories seem to end up in surprisingly similar recommendations for facilitating sustainable change. In this chapter, we explore the differences and similarities of two theoretical bodies that rarely interact, with the aim to explore the room for breaking out of disciplinary silos and investigate potentials for cross-field pollination. We use the empirical case of continuity and change in meat consumption, but the dynamics discussed are arguably relevant for all fields of consumption. We demonstrate that while cross-pollination between nudge and practice theories could potentially increase political attention as well as be used to deliver more precise and tailored interventions, the diverging ontological underpinnings of these directions of thought significantly reduce the potential for further co-development.

Details

Consumers and Consumption in Comparison
Type: Book
ISBN: 978-1-83549-315-1

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