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1 – 10 of 682N.B. Crane, J. Tuckerman and G.N. Nielson
Additive manufacturing (AM) offers substantial flexibility in shape, but much less flexibility in materials and functionality – particularly at small size scales. A system for…
Abstract
Purpose
Additive manufacturing (AM) offers substantial flexibility in shape, but much less flexibility in materials and functionality – particularly at small size scales. A system for automatically incorporating microscale components would enable the fabrication of objects with more functionality. The purpose of this paper is to consider the potential of self‐assembly to serve as an automated programmable integration method. In particular, it addresses the ability of random self‐assembly processes to successfully assemble objects with high performance despite the possibility of assembly errors.
Design/methodology/approach
A self‐assembled thermoelectric system is taken as a sample system. The performance expectations for these systems are then predicted using modified one‐dimensional models that incorporate the effects of random errors. Monte‐Carlo simulation is used to predict the likely performance of self‐assembled thermoelectric systems and evaluate the impact of key process and system design parameters.
Findings
While assembly yield can drop quickly with increasing numbers of assembled parts, large functional assemblies can be constructed by arranging components in parallel to provide redundancy. In some cases, the performance losses are minimal. Alternatively, sensing can be incorporated to identify perfect assemblies. For small assemblies, the probability of perfection may be high enough to achieve an acceptable assembly rate. Small assemblies could then be combined into larger functional systems.
Originality/value
The paper identifies two strategies that can guide the development of AM processes that incorporate miniature components to increase the system functionality. The analysis shows that this may be possible despite significant errors in the self‐assembly process because systems may be tolerant of significant assembly errors.
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Christian Baechler, Matthew DeVuono and Joshua M. Pearce
A low‐cost, open source, self‐replicating rapid prototyper (RepRap) has been developed, which greatly expands the potential user base of rapid prototypers. The operating cost of…
Abstract
Purpose
A low‐cost, open source, self‐replicating rapid prototyper (RepRap) has been developed, which greatly expands the potential user base of rapid prototypers. The operating cost of the RepRap can be further reduced using waste polymers as feedstock. Centralized recycling of polymers is often uneconomic and energy intensive due to transportation embodied energy. The purpose of this paper is to provide a proof of concept for high‐value recycling of waste polymers at distributed creation sites.
Design/methodology/approach
Previous designs of waste plastic extruders (also known as RecycleBots) were evaluated using a weighted evaluation matrix. An updated design was completed and the description and analysis of the design is presented including component summary, testing procedures, a basic life cycle analysis and extrusion results. The filament was tested for consistency of density and diameter while quantifying electricity consumption.
Findings
Filament was successfully extruded at an average rate of 90 mm/min and used to print parts. The filament averaged 2.805 mm diameter with 87 per cent of samples between 2.540 mm and 3.081 mm. The average mass was 0.564 g/100 mm length. Energy use was 0.06 kWh/m.
Practical implications
The success of the RecycleBot further reduces RepRap operating costs, which enables distributed in‐home, value added, plastic recycling. This has implications for municipal waste management programs, as in‐home recycling could reduce cost and greenhouse gas emissions associated with waste collection and transportation, as well as the environmental impact of manufacturing custom plastic parts.
Originality/value
This paper reports on the first technical evaluation of a feedstock filament for the RepRap from waste plastic material made in a distributed recycling device.
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Kai-Ming Yu, Yu Wang and Charlie C.L. Wang
In the newly released ASTM standard specification for additive manufacturing file (AMF) format – version 1.1 – Hermite curve-based interpolation is used to refine input triangles…
Abstract
Purpose
In the newly released ASTM standard specification for additive manufacturing file (AMF) format – version 1.1 – Hermite curve-based interpolation is used to refine input triangles to generate denser mesh with smoother geometry. This paper aims to study the problems of constructing smooth geometry based on Hermite interpolation on curves and proposes a solution to overcome these problems.
Design/methodology/approach
A formulation using triangular Bézier patch is proposed to generate smooth geometry from input polygonal models. Different configurations on the boundary curves in the formulation are analyzed to further enrich this formulation.
Findings
The study shows that the formulation given in the AMF format (version 1.1) can lead to the problems of inconsistent normals and undefined end-tangents.
Research limitations/implications
The scheme has requirements on the input normals of a model, only C0 interpolation can be generated on those cases with less-proper input.
Originality/value
To overcome the problems of smooth geometry generation in the AMF format, the authors propose an enriched scheme for computing smooth geometry by using triangular Bézier patch. For the configurations with less-proper input, the authors adopt the Boolean sum and the Nielson’s point-opposite edge interpolation for triangular Coons patch to generate the smooth geometry as a C0 interpolant.
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Nielson Veloso Medeiros, Emanuel Negrão Macêdo, Rui Nelson Otoni Magno, Claudio José Cavalcante Blanco and João Nazareno Nonato Quaresma
The aim of this paper is related to an analysis of hydrodynamic lubrication of circular thrust bearings.
Abstract
Purpose
The aim of this paper is related to an analysis of hydrodynamic lubrication of circular thrust bearings.
Design/methodology/approach
The modified Reynolds equation was treated to obtain a hybrid numerical-analytical solution through the generalized integral transform technique (GITT) for the problem.
Findings
Numerical results for the engineering parameters such as pressure field, load capacity and power consumption were thus produced as functions of the radial and circumferential directions. These parameters depend on the geometry of sector-shaped used: Rayleigh pad with 4, 8 and 16 steps. Comparing among them, on the numerical point of view, the Rayleigh pad geometry with N = 16 steps has a better satisfactory performance because it has a lower power consumption.
Originality/value
The present GITT results and those obtained by the finite volume method (FVM) from previous works in the literature were confronted to verify whether the results are consistent and to demonstrate the capacity of the GITT approach in handling thrust bearing problems.
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P. D. Harms, Dina V. Krasikova, Adam J. Vanhove, Mitchel N. Herian and Paul B. Lester
This chapter examines the role of stress and emotional well-being as critical antecedents of important outcomes in the military context. In it, we provide a framework for…
Abstract
This chapter examines the role of stress and emotional well-being as critical antecedents of important outcomes in the military context. In it, we provide a framework for understanding the sources of stress among military personnel. Using this model, we review the risk factors associated with combat and deployment cycles in addition to protective factors, such as personality characteristics and social support, which mitigate the effects of stress on emotional well-being and performance. Finally, we evaluate efforts by military organizations to enhance the emotional well-being of service members through training programs designed to build resiliency.
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This study provides a comprehensive framework of adaptation in triadic business relationship settings in the service sector. The framework is based on the industrial network…
Abstract
This study provides a comprehensive framework of adaptation in triadic business relationship settings in the service sector. The framework is based on the industrial network approach (see, e.g., Axelsson & Easton, 1992; Håkansson & Snehota, 1995a). The study describes how adaptations initiate, how they progress, and what the outcomes of these adaptations are. Furthermore, the framework takes into account how adaptations spread in triadic relationship settings. The empirical context is corporate travel management, which is a chain of activities where an industrial enterprise, and its preferred travel agency and service supplier partners combine their resources. The scientific philosophy, on which the knowledge creation is based, is realist ontology. Epistemologically, the study relies on constructionist processes and interpretation. Case studies with in-depth interviews are the main source of data.
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Connie R Wanberg, Elizabeth T Welsh and Sarah A Hezlett
Organizations have become increasingly interested in developing their human resources. One tool that has been explored in this quest is mentoring. This has led to a surge in…
Abstract
Organizations have become increasingly interested in developing their human resources. One tool that has been explored in this quest is mentoring. This has led to a surge in mentoring research and an increase in the number of formal mentoring programs implemented in organizations. This review provides a survey of the empirical work on mentoring that is organized around the major questions that have been investigated. Then a conceptual model, focused on formal mentoring relationships, is developed to help understand the mentoring process. The model draws upon research from a diverse body of literature, including interpersonal relationships, career success, training and development, and informal mentoring. Finally, a discussion of critical next steps for research in the mentoring domain is presented.
YouTube's vast and engaged user base makes it central to firms' digital marketing effort. With extant studies focusing on viewers' post-view engagement behavior, however, research…
Abstract
Purpose
YouTube's vast and engaged user base makes it central to firms' digital marketing effort. With extant studies focusing on viewers' post-view engagement behavior, however, research into what motivates viewers to click on and watch YouTube videos is scarce. This study investigates the implications of marketers' video optimization practices for video views on YouTube.
Design/methodology/approach
The study employed a data set of videos (N = 4,398) gathered by scraping YouTube's trending list. Using a combination of text and sentiment analysis, the study measured four video optimization practices: information content of video titles, emotional intensity of video titles, information content of video descriptions and volume of video tags. It then analyzed the effect of these video optimization practices on video views.
Findings
The study finds that greater availability of information in video titles is negatively associated with video views, whereas intensity of negative emotional sentiment in video titles is positively associated with video views. Further, greater availability of information in video descriptions is positively associated with video views. Finally, an inverted U-shaped relationship is found between volume of video tags and video views. Up to 17 video tags can contribute to more video views; however, beyond 17 tags, the relationship turns negative.
Originality/value
This study investigates the effect of marketers' video optimization practices on video views. While extant studies mainly focus on viewers' post-view engagement behavior, such as liking, commenting on and sharing videos, this study examines video views. Similarly, extant studies investigate videos' internal content, while this study investigates elements of the video metadata.
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Sunday O. Obi, Festus E. Obiakor, Stephanie L. Obi, Tachelle Banks, Sean Warner and Natalie Spencer
The historian, Arthur M. Schlesinger (1999), once wrote that “a basic theme of American history has been the movement, uneven but steady, from exclusion to inclusion” – a movement…
Abstract
The historian, Arthur M. Schlesinger (1999), once wrote that “a basic theme of American history has been the movement, uneven but steady, from exclusion to inclusion” – a movement “fueled by ideals” (p. 173). He might well have been talking about the United States’ public education system where it has become evident that segments of its pupil population have been overlooked or neglected. The good news is that there have been some efforts to ameliorate this problem. However, despite these efforts, there continues to be lingering problems for culturally and linguistically diverse students with gifts and talents. In this chapter, we address how to maximize the success potential of these students.
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