Iván La Fé-Perdomo, Jorge Andres Ramos-Grez, Ramón Quiza, Ignacio Jeria and Carolina Guerra
316 L stainless steel alloy is potentially the most used material in the selective laser melting (SLM) process because of its versatility and broad fields of applications (e.g…
Abstract
Purpose
316 L stainless steel alloy is potentially the most used material in the selective laser melting (SLM) process because of its versatility and broad fields of applications (e.g. medical devices, tooling, automotive, etc.). That is why producing fully functional parts through optimal printing configuration is still a key issue to be addressed. This paper aims to present an entirely new framework for simultaneously reducing surface roughness (SR) while increasing the material processing rate in the SLM process of 316L stainless steel, keeping fundamental mechanical properties within their allowable range.
Design/methodology/approach
Considering the nonlinear relationship between the printing parameters and features analyzed in the entire experimental space, machine learning and statistical modeling methods were defined to describe the behavior of the selected variables in the as-built conditions. First, the Box–Behnken design was adopted and corresponding experimental planning was conducted to measure the required variables. Second, the relationship between the laser power, scanning speed, hatch distance, layer thickness and selected responses was modeled using empirical methods. Subsequently, three heuristic algorithms (nonsorting genetic algorithm, multi-objective particle swarm optimization and cross-entropy method) were used and compared to search for the Pareto solutions of the formulated multi-objective problem.
Findings
A minimum SR value of approximately 12.83 μm and a maximum material processing rate of 2.35 mm3/s were achieved. Finally, some verification experiments recommended by the decision-making system implemented strongly confirmed the reliability of the proposed optimization methodology by providing the ultimate part qualities and their mechanical properties nearly identical to those defined in the literature, with only approximately 10% of error at the maximum.
Originality/value
To the best of the authors’ knowledge, this is the first study dealing with an entirely different and more comprehensive approach for optimizing the 316 L SLM process, embedding it in a unique framework of mechanical and surface properties and material processing rate.
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Germán Omar Barrionuevo, Jorge Andrés Ramos-Grez, Magdalena Walczak, Xavier Sánchez-Sánchez, Carolina Guerra, Alexis Debut and Edison Haro
The effect of processing parameters on the microstructure of steel produced by laser-based powder bed fusion (LPBF) is a recognized opportunity for property design through…
Abstract
Purpose
The effect of processing parameters on the microstructure of steel produced by laser-based powder bed fusion (LPBF) is a recognized opportunity for property design through microstructure control. Because the LPBF generates a textured microstructure associated with high anisotropy, it is of interest to determine the fabrication plane that would generate the desired property distribution within a component.
Design/methodology/approach
The microstructure of 316 L produced by LPBF was characterized experimentally (optical, scanning electron microscopy, glow discharge emission spectrometry and X-ray diffraction), and a finite element method was used to study the microstructure features of grain diameter, grain orientation and thermal parameters of cooling rate, thermal gradient and molten pool dimensions.
Findings
The computational tool of Ansys Additive was found efficient in reproducing the experimental effect of varying laser power, scanning speed and hatch spacing on the microstructure. In particular, the conditions for obtaining maximum densification and minimum fusion defects were consistent with the experiment, and the features of higher microhardness near the component’s surface and distribution of surface roughness were also reproduced.
Originality/value
To the best of the author’s knowledge, this paper is believed to be the first systematic attempt to use Ansys Additive to investigate the anisotropy of the 316 L SS produced by LPBF.
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Nathália de Fátima Joaquim, Ana Carolina Guerra and Alexandre de Pádua Carrieri
The aim of this article is to carry out a critical analysis of the view that core countries’ knowledge holds sway over that of the periphery and to offer a reassessment of…
Abstract
Purpose
The aim of this article is to carry out a critical analysis of the view that core countries’ knowledge holds sway over that of the periphery and to offer a reassessment of Lahiri’s Anglo-Eurocentric point of view and the implications this has for scientific discussion in the field of management. To do this the authors made use of both Lahiri’s (2011) comments as a representative of mainstream thought and the existing literature on this issue.
Design/methodology/approach
In this research, the authors used the methodology proposed by Lahiri (2011), but with some adjustments that they thought were necessary. They also analysed scientific production on management in the most important Brazilian journals to put the field of organizational studies in Brazil in context and to situate the reader as regarding their criticism of the North-centric viewpoint. This is because the authors consider organizational studies as a synonym for management studies.
Findings
The results presented in Lahiri’s (2011) article “Brazil-focused publications in leading business journals” are invalid because the sample on which the article is based is limited to 14 academic journals, of which 7 are American, 6 are British and 1 is German. It can be questioned whether this particular selection of journals accurately represents the corpus of publications that deal with Brazil, given that Lahiri does not include any articles published in Brazil and thus reinforces his North-centric standpoint. Moreover, the article emphasizes authors with ties to English institutions and concludes that the most relevant academic contributions on Brazil have been produced at non-Brazilian institutions. Moreover, the authors also discovered a contradiction in the sample that is important for the thesis presented in this article because, in fact, the scholars selected for the sample emphasized in that work have ties to both a foreign and a Brazilian institution.
Originality/value
The originality of this article lies in the fact that it proposes to discuss the production and consumption of knowledge in the area of administration in such a way as to reassess North-centric hegemony in this field.
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This chapter explores the provision of library services to children residing in juvenile justice facilities. The small body of scholarly literature published on the topic over the…
Abstract
This chapter explores the provision of library services to children residing in juvenile justice facilities. The small body of scholarly literature published on the topic over the last 50 years is examined, followed by a description of the findings of a recent Australian survey of juvenile justice library provision in that country. Australia presents a very poor example of the provision of library services to children living in correctional detention. A contrast to the Australian context is provided through a case study of the library service to the South Carolina Birchwood School, in the United States. Housed in the South Carolina Juvenile Justice Centre, the Birchwood School library is presented as an example of better practice and an illustration of what can be achieved by a juvenile justice facility library when it is sufficiently staffed and funded. Opportunities for further research are identified and conclusions are drawn regarding the need for libraries in juvenile justice facilities.
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Hyejo Hailey Shin, Miyoung Jeong, Natalia Zapata-Cuervo, Maricela Isabel Montes Guerra, Mi-Hea Cho and Yensoon Kim
This study aims to investigate how customers’ perceived risks of sharing economy (SE) affect their self-protective behaviors when using SE, leading to their future behavioral…
Abstract
Purpose
This study aims to investigate how customers’ perceived risks of sharing economy (SE) affect their self-protective behaviors when using SE, leading to their future behavioral intention. Additionally, this study looks into whether there are any differences between accommodation-sharing and ride-sharing customers in the aforementioned relationships.
Design/methodology/approach
An online survey targeting two groups of SE customers (i.e. accommodation sharing and ride sharing) was used. Using partial least squares structural equation modeling, the mechanism of how SE customers’ perceived risks of SE affect their self-protective behaviors, which in turn influence their future behavior intention. A multigroup analysis was performed to assess the difference between the two groups of SE customers. Finally, a multivariate analysis of variance (MANOVA) was conducted to see the potential differences between the five classifications of self-protective behaviors in their perceived risks.
Findings
SE customers’ psychological risks positively affected their hygiene protective behaviors and social protective behaviors, influencing their behavior intention and relative intention (compared with traditional services). Social risk had a negative impact on SE customers’ hygiene protective behaviors. There was a significant difference between accommodation sharing and ride sharing customers in their psychological mechanism of how perceived risks influence their self-protective behaviors.
Practical implications
The findings of this study help SE platforms and service providers better understand their customers’ perceived risks of their services and suggest them to promote their customers’ self-protective behaviors so that perceived risks can be mitigated, thereby generating strong behavior intentions. As the results indicated that there is a significant difference between the two major forms of SE (i.e. accommodation sharing and ride sharing) in their customers’ perceived risks and self-protective behavior, SE platforms can further refine their operational and marketing efforts based on the findings.
Originality/value
This study offers a comprehensive understanding of SE customers’ self-protective behaviors by examining the effects of SE customers’ different perceived risks on their self-protective behaviors during the unprecedented pandemic. Furthermore, the comparison of the two most popular forms of SE (i.e. accommodation sharing and ride sharing) provides new perspectives to understand customers’ behavior in the SE context.
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Galen H. Smith and Teresa L. Scheid
The race concordance hypothesis suggests that matching patients and health providers on the basis of race improves communication and patients’ perceptions of health care, and by…
Abstract
Purpose
The race concordance hypothesis suggests that matching patients and health providers on the basis of race improves communication and patients’ perceptions of health care, and by extension, encourages patients to seek and utilize health care, which may reduce health disparities. However, relatively few studies have examined the impact of race concordance on the utilization of health services. This chapter is grounded on Andersen’s Emerging Model of Health Services Utilization (Phase 4) and extends that model to include race concordance.
Methodology/approach
The data were collected from a stratified random sample of adult beneficiaries enrolled in North Carolina Medicaid’s primary care case management delivery system in 2006–2007. Propensity score matching techniques were used to sort respondents on their propensity for race concordance and indices were constructed to generate key control variables. Poisson regression was used to examine the impact of race concordance on the utilization of primary care and emergency room care, under the assumption that race concordance would increase the use of primary care and decrease the use of emergency care for minority patients.
Findings
While blacks (compared to whites) used less primary care and had more emergency care visits, race concordance was not a statistically significant predictor of either primary care or emergency room use. However, patients’ satisfaction with their primary care providers was associated with significantly fewer primary care and emergency care visits while trust in one’s provider was associated with more primary care visits.
Research implications
The study findings suggest that the central premises of the race concordance hypothesis require further study to confirm the assumption that better patient – primary care provider relationships result in less utilization of more costly and resource-intensive forms of health care.
Value of chapter
The study makes a valuable contribution by expanding the relatively small body of literature dedicated to exploring the impact of race concordance on health services utilization. Additionally, by virtue of researching the experience of Medicaid enrollees, the study controls for health insurance status.
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Frederick C. Buskey and Meagan Karvonen
Educational leadership preparation programs are expected to train graduates who change their practice and produce outcomes for teachers and students. However, programs are…
Abstract
Educational leadership preparation programs are expected to train graduates who change their practice and produce outcomes for teachers and students. However, programs are challenged to produce evidence of their impact while also evaluating for formative purposes. This paper describes collaboration between an educational leadership program director and a program evaluator to construct an evaluation system that incorporated program theory, processes, and outcomes. The leadership preparation program, grounded in ethical leadership practices, had a unique design with core tenets that informed choices about the evaluation design. Decisions about data sources were informed by evaluation foci, the availability of existing data sources, and resource constraints. The complexity of the evaluation design paralleled the complexity of the program itself. Leadership content expertise, evaluation design expertise, and genuine collaboration were all essential to the successful design of this evaluation plan. Several recommendations are offered for others collaborating to design evaluations of their programs.
Maria Alice Nunes Costa, Carolina Doria Romeo Losicer, Jessica Guerra Inácio de Oliveira and Bruno Silva Faria
This chapter is a case study of Companhia Siderúrgica Nacional (CSN, National Steel Company, Volta Redonda, Rio de Janeiro, Brazil), in order to compare two models of social…
Abstract
This chapter is a case study of Companhia Siderúrgica Nacional (CSN, National Steel Company, Volta Redonda, Rio de Janeiro, Brazil), in order to compare two models of social responsibility adopted by the same company in two different historical periods: when it was state-owned company (since forties) and then when it was privatized in the 1990s. The results are preliminary for this case study, in that the research is ongoing. However, we can anticipate a main conclusion, that CSN has no social responsibility with its main stakeholders: the community of city Volta Redonda, where industrial activities are carried out. This research is relevant for future research in the comparative perspective, in poor or developing countries such as Brazil. We add that this study has led us to build the concept of territorial social responsibility, in order to broaden and move beyond the debate focused on social responsibility in the corporate world and move towards a transnational reflection of what is liability to the planet.