Influence of the notch-sharpening technique on styrene-acrylonitrile fracture behavior

The Centre Catala del Plastic and Universidad Rey Juan Carlos laboratories joined forces to investigate the effect of the notch-sharpening technique on the fracture parameters of styrene-acrylonitrile. Contact notch-sharpening techniques, such as razor tapping, razor sliding, and razor broaching, and a noncontact procedure, femtolaser, were analyzed. The fracture values of the samples with notches sharpened via contact techniques were divided into two groups: one with pop-in and the other with no pop-in in the load-displacement records; this resulted in the lowest and highest fracture toughnesses, respectively. The fracture parameters of the specimens with notches sharpened via a femtolaser were between those of the samples with notches sharpened via contact procedures in which pop-in occurred and those in which it did not. To explain these results, the crack front of the nontested specimens after sharpening was investigated in depth, we identified the type of damage and measured its size and the crack tip radii. The morphology of the crack front was related to the fractographic study.Postprint (author's final draft

Estudio integral del proceso de temple por láser con ópticas tipo escáner: Modelización, experimentación y control

288 p.El trabajo de tesis presenta el desarrollo de una metodología basada en el empleo de una óptica móvil o una óptica de tipo escáner para su uso en operaciones de temple por láser. Este trabajo, realizado en el Dpto. de Ingeniería Mecánica de la Universidad del País Vasco UPV/EHU, se basa en el análisis y desarrollo de una nueva configuración de máquina basada en el empleo de ópticas móviles para su empleo en el proceso de temple por láser en la industria, aportando la posibilidad de variar el tamaño de la zona templada en cada momento, así como de controlar la densidad de energía aplicada.Este enfoque, muy poco estudiado en la bibliografía tanto científica como industrial, se basa en un desarrollo integral del proceso apoyado en tres pilares: El desarrollo del control, la mecatrónica y la puesta a punto del sistema, la modelización del proceso y la validación experimental

Because I'm Happy: Exploring the Happiness of Shopping in Social Enterprises and its Effect on Customer Satisfaction and Loyalty

[Abstract] Purpose: This research analyzes the role of happiness associated with sustainable purchases in social enterprises (SEs) as a key precursor of prosocial behavioral responses through satisfaction with such purchases. Design/methodology/approach: This paper studies the relationships between past purchase in a social enterprise, consumer happiness, satisfaction and three indicators of loyalty: repurchase intention, word-of-mouth (WOM) intention and willingness to pay more. In addition, it analyzes the moderating role of altruistic motivation. A survey was designed to collect data from 380 consumers who had bought in a social enterprise. Findings: Sustainable consumption is a source of happiness for ethical consumers to the extent that they feel that they meet a personal need or desire, and they contribute to achieving a social objective with their purchasing behavior. Practical implication: SEs must appeal to the happiness of consumers as a strategic line to achieve their satisfaction and loyalty. Social enterprise practitioners and marketers should deploy organizational capabilities and resources in key performing areas such as communication, customer service or shopping experience, with the purpose of maximizing the happiness of ethical consumers with whom the firm is interacting for the first time. Originality/value: This research highlights the importance of the social enterprise in the commercial setting, since it has been proven that purchases in these companies generate happiness and satisfaction in consumers. In addition, satisfaction has a great impact on their loyalty, which is a direct advantage for this type of company and an indirect one for society as a wholeThis research was funded by the MICINN National Project CO-CRESEO: The co-creation of value in social enterprises. Effects of the omnichannel strategy (PID 2019-109580RB-I00/AEI/10.13039/501100011033)

Connecting Social Enterprises and Sustainable Consumption: Systematic Review, Bibliometric Analysis, and Conceptual Framework

[Abstract]: The purpose of this study is to explore the meeting point between social enterprises (SEs) and sustainable consumption, given the proven potential of these hybrid organizations in the achievement of sustainable development. Paradoxically, scholarly attention has been scarce to this field of research, particularly from the perspectives of SE products and (potential) customers. Aiming to shed some light, a systematic literature review was conducted, resulting in 24 scientific publications descriptively and thematically explored based on a bibliometric analysis. The findings show that the link between SEs and sustainable consumption is very recent and that empirical articles using quantitative methodologies prevail focused on the analysis of capabilities and performances of SEs aiming to positively influence customers’ response. Nevertheless, the attention to the identification of product attributes and the individual determinants effective enough to press the buy button is still limited. In response to this shortcoming, the originality of this study consists of assembling the findings in this regard into an integrated conceptual framework that paves the way for future analysis in this field of studyMICINN National Project CO-CRESEO ; PID2019-109580RB-I00/AEI/10.13039/ 50110001103

Sedentarismo y condición física en mujeres post-menopáusicas

Objetivos: establecer la relación entre un comportamiento sedentario (permanecer sentada ≥4 horas/día) y la condición física en 457 mujeres ≥65 años. Metodología: la condición física se evaluó mediante 8 test (batería ‘Senior Fitness Test’). Se utilizó ANOVA para analizar diferencias entre grupos en función de las horas de sedestación y regresión logística para estudiar la asociación del comportamiento sedentario con baja condición física, utilizando como referencia el percentil 20 de los valores normativos en España (Proyecto EXERNET). Resultados: las mujeres sedentarias obtuvieron valores más bajos en las pruebas de equilibrio, fuerza de piernas y brazo izquierdo, flexibilidad de brazos y velocidad (p<0.05). Además, aquellas mujeres que permanecían sentadas ≥4 horas/día presentaban mayor riesgo de baja condición física en las pruebas citadas anteriormente, independientemente de las horas dedicadas a caminar (p<0.05). Conclusión: permanecer mucho tiempo sentada influye negativamente sobre la condición física de las mujeres postmenopáusicas independientemente del tiempo que caminen

Analysis of the Part Distortions for Inconel 718 SLM: A Case Study on the NIST Test Artifact

The present paper evaluates the misalignment and geometry distortion of the standard National Institute of Standards and Technology (NIST) test artifact in Inconel 718 alloy, when several layers with and without supports are employed to manufacture it by the Selective Laser Melting (SLM) process. To this end, a coordinate-measuring machine (CMM) is used to measure the geometrical distortion in each manufacturing configuration, following the same measurement protocol. The results show that the laser path strategy favors a thermal gradient which, consequently, induces geometrical distortions in the part. To prove this hypothesis, a numerical simulation is performed to determine the thermal gradient and the pattern of the residual stresses. It was found that the geometrical distortion certainly depends on the position of the feature position and laser strategy, where thermal cycles and residual thermal stresses had an impact in the end-part geometry, especially if a high strength-to-weight ratio commonly used in aeronautics is present.This work is supported by the Serra Húnter program (Generalitat de Catalunya) reference number [UPC-LE-304 (2018)] and by the Aeronautics Advanced Manufacturing Center (CFAA) in the JANO—Joint action toward digital transformation project framework. Diego Celentano acknowledges Pontificia Universidad Católica de Chile (PUC), Wallonie-Bruxelles International (WBI) and National Council for Scientific and Technological Research CONICYT (FONDECYT Projects No. 3180006 and 1180591) for the financial supports provided for this work

Effect of powder particle size distribution on the surface finish of components manufactured by laser powder bed fusion

One of the key aspects of the laser powder bed fusion (L-PBF) process is the quality of the raw powder since it affects the final properties of the manufactured parts. In this study, 13 batches of Inconel (R) 718 powder were analysed, all of them being specially designed for L-PBF technology and meeting similar requirements but coming from different suppliers. Therefore, these batches have certain differences in their characteristics, including the particle size distribution (PSD). This study presents the relationship between the PSD of each batch and the surface roughness obtained in the manufactured parts. For the roughness study, Sa and Sz parameters are presented; in addition, the size and frequency of the particles adhered to the surface were quantified, and an autocorrelation analysis was carried out. Furthermore, after this analysis, the parts were sandblasted in order to repeat the same analysis after removing the adhered particles from the surface. This work points to the fact that the particles adhered to the surface are the smallest particles in the powder batch, and their size affects the roughness of the final part. This means that the surface roughness is strongly related to the fraction of smaller particles within the PSD of the batch, while there is no relationship between the surface roughness and the larger particles.Open Access funding provided by UPV/EHU thanks to the CRUE-CSIC agreement with Springer Nature. This research was funded by the Basque Government under the ELKARTEK Program, EDISON project, grant number KK-2022/00070

The Effect of the Laser Incidence Angle in the Surface of L-PBF Processed Parts

The manufacture of multiple parts on the same platform is a common procedure in the Laser Powder Bed Fusion (L-PBF) process. The main advantage is that the entire working volume of the machine is used and a greater number of parts are obtained, thus reducing inert gas volume, raw powder consumption, and manufacturing time. However, one of the main disadvantages of this method is the possible differences in quality and surface finish of the different parts manufactured on the same platform depending on their orientation and location, even if they are manufactured with the same process parameters and raw powder material. Throughout this study, these surface quality differences were studied, focusing on the variation of the surface roughness with the angle of incidence of the laser with respect to the platform. First, a characterization test was carried out to understand the behavior of the laser in the different areas of the platform. Then, the surface roughness, microstructure, and minimum thickness of vertical walls were analyzed in the different areas of the platform. These results were related to the angle of incidence of the laser. As it was observed, the laser is completely perpendicular only in the center of the platform, whilst at the border of the platform, due to the incidence angle, it melts an elliptical area, which affects the roughness and thickness of the manufactured part. The roughness increases from values of Sa = 5.489 μm in the central part of the platform to 27.473 μm at the outer borders while the thickness of the manufactured thin walls increases around 40 μm.This research was funded by the Spanish Ministry of Industry and Competitiveness under the CDTI JANO project and by Basque Government (Eusko Jaurlaritza) under the ELKARTEK Program, QUALYFAM project, Grant No. KK-2020/00042