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Article
Publication date: 12 December 2023

Austin R. Colon, David Owen Kazmer, Amy M. Peterson and Jonathan E. Seppala

A main cause of defects within material extrusion (MatEx) additive manufacturing is the nonisothermal condition in the hot end, which causes inconsistent extrusion and polymer…

188

Abstract

Purpose

A main cause of defects within material extrusion (MatEx) additive manufacturing is the nonisothermal condition in the hot end, which causes inconsistent extrusion and polymer welding. This paper aims to validate a custom hot end design intended to heat the thermoplastic to form a melt prior to the nozzle and to reduce variability in melt temperature. A full 3D temperature verification methodology for hot ends is also presented.

Design/methodology/approach

Infrared (IR) thermography of steady-state extrusion for varying volumetric flow rates, hot end temperature setpoints and nozzle orifice diameters provides data for model validation. A finite-element model is used to predict the temperature of the extrudate. Model tuning demonstrates the effects of different model assumptions on the simulated melt temperature.

Findings

The experimental results show that the measured temperature and variance are functions of volumetric flow rate, temperature setpoint and the nozzle orifice diameter. Convection to the surrounding air is a primary heat transfer mechanism. The custom hot end brings the melt to its setpoint temperature prior to entering the nozzle.

Originality/value

This work provides a full set of steady-state IR thermography data for various parameter settings. It also provides insight into the performance of a custom hot end designed to improve the robustness of melting in MatEx. Finally, it proposes a strategy for modeling such systems that incorporates the metal components and the air around the system.

Details

Rapid Prototyping Journal, vol. 30 no. 1
Type: Research Article
ISSN: 1355-2546

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Article
Publication date: 22 August 2017

Anthony A. D’Amico, Analise Debaie and Amy M. Peterson

The aim of this paper is to examine the impact of layer thickness on irreversible thermal expansion, residual stress and mechanical properties of additively manufactured parts.

1198

Abstract

Purpose

The aim of this paper is to examine the impact of layer thickness on irreversible thermal expansion, residual stress and mechanical properties of additively manufactured parts.

Design/methodology/approach

Samples were printed at several layer thicknesses, and their irreversible thermal expansion, tensile strength and flexural strength were determined.

Findings

Irreversible thermal strain increases with decreasing layer thickness, up to 22 per cent strain. Tensile and flexural strengths exhibited a peak at a layer thickness of 200 μm although the maximum was not statistically significant at a 95 per cent confidence interval. Tensile strength was 54 to 97 per cent of reported values for injection molded acrylonitrile butadiene styrene (ABS) and 29 to 73 per cent of those reported for bulk ABS. Flexural strength was 18 to 41 per cent of reported flexural strength for bulk ABS.

Practical implications

The large irreversible thermal strain exhibited that corresponding residual stresses could lead to failure of additively manufactured parts over time. Additionally, the observed irreversible thermal strains could enable thermally responsive shape in additively manufactured parts. Variation in mechanical properties with layer thickness will also affect manufactured parts.

Originality/value

Tailorable irreversible thermal strain of this magnitude has not been previously reported for additively manufactured parts. This strain occurs in parts made with both high-end and consumer grade fused deposition modeling machines. Additionally, the impact of layer thickness on tensile and flexural properties of additively manufactured parts has received limited attention in the literature.

Details

Rapid Prototyping Journal, vol. 23 no. 5
Type: Research Article
ISSN: 1355-2546

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Book part
Publication date: 12 October 2011

Shira M. Peterson and Amy C. Baker

Understanding the complexity of the change process is critical if early childhood improvement initiatives are to result in lasting change. One of the keys to effective programs…

Abstract

Understanding the complexity of the change process is critical if early childhood improvement initiatives are to result in lasting change. One of the keys to effective programs and efficient use of resources is an understanding of readiness to change. This chapter presents a theoretical approach to understanding readiness to change in the field of early education and care. We describe applications of this approach used within a community-wide initiative in Rochester, New York, funded by an Early Childhood Educator Professional Development grant. The goal of the initiative was to create an integrated professional development system from entry level through the completion of a bachelor degree, with the priorities of increasing access, alignment, and articulation. We describe interventions at the community, organization, and individual level, and explore the impact of readiness to change at each of these levels.

Evaluation results show that educators enrolled in the research-based mentoring program offered by this grant became involved in other types of professional development programs, made significant gains in the quality of the classroom environment, and had children who made gains in overall development and vocabulary beyond developmental expectations. We conclude with a discussion of these results as well as implications for policy, practice, and future research.

Details

The Early Childhood Educator Professional Development Grant: Research and Practice
Type: Book
ISBN: 978-0-85724-280-8

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Book part
Publication date: 21 November 2022

Albert Somit and Steven A. Peterson

Biology and Politics (or Biopolitics) has been a part of the political science firmament since the 1960s. Over time, it has become less an odd outlier in the discipline and more a…

Abstract

Biology and Politics (or Biopolitics) has been a part of the political science firmament since the 1960s. Over time, it has become less an odd outlier in the discipline and more a tolerated (and sometimes respected) part of the enterprise. After about 50 years of existence, this is a proper time to reflect on where biopolitics has been, where it is now, and where it might go as an academic endeavor. Indeed, some have said that the best step would for biopolitics to no longer be seen as a special, narrow part of political science – but a part of every field in the discipline, integrated into the larger world of the study of politics.

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Article
Publication date: 30 November 2005

Cecile K. M. Crutzen

Questioning gender is about taking an active, critical role in the technological design of our daily behaviour. It is a deconstruction of the oppositions that exist in the…

252

Abstract

Questioning gender is about taking an active, critical role in the technological design of our daily behaviour. It is a deconstruction of the oppositions that exist in the discourses of Ambient Intelligence designers, the ICT industry and computer scientists. What underlies the assumption that Ambient Intelligence will, by disappearing into our environment, bring humans both an easy and entertaining life? The gender perspective can uncover power relations within the promotion and realisation of Ambient Intelligence that satisfy an obvious wish for a technological heaven. The deconstruction of the promise of progress and a better life reveals what is overvalued, what is undervalued and what is ignored. This paper is a deconstruction of the view, currently prevalent in the discourses of Ambient Intelligence; a view of humans and the way they live. A view that will influence the way women and men will be allowed to construct their lives.

Details

Journal of Information, Communication and Ethics in Society, vol. 3 no. 4
Type: Research Article
ISSN: 1477-996X

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Book part
Publication date: 21 November 2022

Tony Wohlers and Amy Fletcher

Abstract

Details

Biopolitics at 50 Years
Type: Book
ISBN: 978-1-80262-108-2

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Book part
Publication date: 21 November 2022

Free Access. Free Access

Abstract

Details

Biopolitics at 50 Years
Type: Book
ISBN: 978-1-80262-108-2

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Book part
Publication date: 24 August 2017

Amy C. Edmondson and Jean-François Harvey

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Extreme Teaming
Type: Book
ISBN: 978-1-78635-449-5

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Book part
Publication date: 20 October 2016

Corey Shdaimah and Chrysanthi S. Leon

Very little research has examined how prostitute women relate to each other. Drawing on interviews, focus groups, and observations with 76 women engaged in street-level…

Abstract

Very little research has examined how prostitute women relate to each other. Drawing on interviews, focus groups, and observations with 76 women engaged in street-level prostitution in Baltimore, Philadelphia, and a mid-Atlantic state, we show how prostitute women provide mutual assistance both to meet their basic needs and as part of their ethical norms, in contrast to the stigmatized characterizations of prostitute women as morally deficient. Women’s relationships offer them concrete support and encouragement while simultaneously producing a counter-narrative that challenges their stigmatized identities.

Details

Special Issue: Problematizing Prostitution: Critical Research and Scholarship
Type: Book
ISBN: 978-1-78635-040-4

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Book part
Publication date: 4 September 2003

Michael W Preis, Salvatore F Divita and Amy K Smith

Missing in most of the research on selling has been an examination of the process from the point of view of the customer. When satisfaction in selling has been considered…

Abstract

Missing in most of the research on selling has been an examination of the process from the point of view of the customer. When satisfaction in selling has been considered, researchers have focused on the satisfaction of the salesperson with his job and/or the impact of this job satisfaction on performance (e.g. Bluen, Barling & Burns, 1990; Churchill, Ford & Walker, 1979; Pruden & Peterson, 1971). To concentrate on salesperson performance while neglecting customers is to ignore the most important half of the relationship between buyers and sellers and entirely disregards the marketing concept and the streams of research in customer satisfaction. This research takes a different approach and examines customers’ satisfaction with salespeople.

Details

Evaluating Marketing Actions and Outcomes
Type: Book
ISBN: 978-0-76231-046-3

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