Releasing systems for aerospace industry based upon shape memory alloys: Characterization of materials for actuators

Releasing and deployment maneuvers carried out during space satellites launching are usually performed by utilizing pyrotechnics loads. However, it is considered convenient to replace this technique by others not requiring explosives (Non Explosive Actuators-NEA). This is mainly due to the necessity of reducing high-shock and vibrations induced levels, also avoiding the contamination of sensible instruments because of dust and gas release during explosion. In addition, the avoidance of risks associated with storage and manipulation of explosives and the possibility of performing device retesting prior to final mounting are desirable qualities. Among NEA devices, those exploiting the singular mechanical behavior of Shape Memory Alloys (SMA) have reached commercial maturity. In this study, the performance of a NEA device that uses the mechanical stress generated upon reverse transformation of a mechanically constrained SMA actuator (constrained recovery effect) to generate the controlled fracture of a notched bolt is analyzed. Firstly, the mechanical components of the system are described, and the main problems associated with its design are introduced. Then, the results of the experimental characterization performed on a NiTi SMA cylindrical tube actuator with 12.7 and 7.8 mm outer and inner diameter respectively, are presented. After an activation stage in which the cylinder is compressed to induce the martensitic phase (or re-orient the existing martensític phase), the temperature is raised while a constant displacement condition is imposed. For temperatures near 120 °C, a loads increment of 35 kN (440 MPa) is obtained. The repetition of this loading-unloading-heating-cooling cycle does not generate any important deterioration in the material response.Fil: Glücksberg, Andrés. Comisión Nacional de Energía Atómica. Gerencia del Área de Energía Nuclear. Instituto Balseiro; ArgentinaFil: Soul, Hugo Ramon. Comisión Nacional de Energía Atómica. Centro Atómico Bariloche; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Yawny, Alejandro Andres. Comisión Nacional de Energía Atómica. Centro Atómico Bariloche; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

The use of indigenous plants as food by a rural community in the Eastern Cape: Tuku 'A' Village, Peddie

In this short contribution the author, a Masters in Environmental Education student, introduces his research into a rural community's knowledge about, attitudes towards and extensive use of plants which grow wild in their locality, with specific reference to their diet. Taking an ethnographic approach to the study of people's relationships with plants, Shava spent a number of weeks in a village in Peddie, South Africa. Here he learned that some young people still know much about wild plants and their uses, but that these plants are playing a decreasing role in their diets. He attributes the growing negative attitudes towards wild plants to modernisation, the non-supportive role of formal education, and advertising which encouraged people to rely on store-bought foods. Environmental educators should consider paying greater attention to the role of "wild" foods in the diet. Such attention can contribute not only to the conservation of biodiversity, but also to greater food security and health

Ethnography of union practices in the Americas: Notes for the delimitation of a research field

El dossier que presentamos tiene el propósito de poner a debate los aportes que una etnografía del accionar sindical puede producir al campo de los estudios sociales e históricos del trabajo y de los trabajadores, como también a los procesos reflexivos que llevan adelante militantes, activistas y trabajadores en pos de la transformación de sus condiciones de vida y trabajo. Esta compilación reúne cinco artículos de destacados investigadores de la temática sindical, que se caracterizan por desarrollar una perspectiva antropológica tanto en la construcción de sus problemas e hipótesis como en el enfoque metodológico.Al delimitar el accionar sindical como campo específico del quehacer etnográfico, proponemos inscribirlo en una articulación conceptual anclada en las prácticas sociales y en la cotidianeidad de la/s clase/s trabajadora/sFil: Soul, Maria Julia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Saavedra 15. Centro de Estudios e Investigaciones Laborales; Argentin

Colectivos Inclusivos y colectivos reivindicativos: Propuesta conceptual para el abordaje de la cotidianeidad laboral

Este artículo presenta las nociones de colectivos inclusivos y colectivos reivindicativos como herramientas para abordar las relaciones propias de la cotidianeidad laboral. Ambas nociones permiten entablar un diálogo crítico con tesis e investigaciones sobre el accionar obrero provenientes de diferentes campos disciplinares. En primer lugar, se presenta el proceso de delimitación empírica de los colectivos inclusivos y reivindicativos. En segundo término, se explicita el entramado teórico que sustenta las nociones propuestas. Finalmente, se desarrollan las categorías propuestas y se plantean hipótesis para el abordaje de las prácticas de los trabajadores.This article presents ideas of inclusive and demanding groups as tools for approaching relations of day to day work. Both ideas allow for establishing a critical dialogue with a thesis and research on workers actions from different fields. In the first place, the process of an empirical outline of inclusive and demanding groups is presented. Secondly, the theoretical framework underpinning the proposed ideas is explained. Finally, the categories which are presented are developed and a hypothesis for approaching practices of workers is formulated.Fil: Soul, Maria Julia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Saavedra 15. Centro de Estudios e Investigaciones Laborales; Argentin

Las instituciones locales en los procesos hegemónicos : Una mirada sobre las relaciones entre industria y comunidad en el caso de San Nicolás de los Arroyos

En este artículo se describen las principales características del entramado institucional que, mediante articulaciones entre entidades estatales y de la sociedad civil, configuró la fisonomía particular de las relaciones de hegemonía/subalternidad en la ciudad de San Nicolás de los Arroyos. El análisis se realiza endos períodos delimitados por las transformaciones que para la comunidad, supuso la instalación de una empresa siderúrgica y las transformaciones derivadas de la privatización de esa misma empresa. Se mostrara cómo las instituciones mediante las cuales los trabajadores industriales se integraron en la ciudad (las organizaciones sindicales, las asociaciones vecinales y entidades culturales y sociales) fueron elementos centrales para la articulación de las políticas estatales y para la canalización de prácticas de participación de los trabajadores en el marco de políticas de desarrollo local)Fil: Soul, Maria Julia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Saavedra 15. Centro de Estudios e Investigaciones Laborales; Argentin

"Acá lo que cambio todo fue la privatización..." : Aproximación antropológica a las prácticas obreras en los espacio laborales en procesos de privatización y reconversión productiva

El objetivo del presente artículo es analizar la configuración concreta de las relaciones de hegemonía en los lugares de trabajo. Con este propósito describimos las políticas de privatización de la empresa siderúrgica estatal (SOMISA) a través del proceso de desestructuración/reestructuración de las relaciones laborales. Identificamos dos elementos que forman parte de la experiencia de los trabajadores desde el período previo a la privatización: la percepción de la inestabilidad laboral y la individualización de las relaciones laborales. Nuestro análisis enfoca las rupturas y continuidades en la experiencia de los trabajadores, concluyendo que las rupturas en la cotidianeidad tienen un importante rol en las explicaciones acerca de la estructuración de los procesos hegemónicos.Fil: Soul, Maria Julia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Saavedra 15. Centro de Estudios e Investigaciones Laborales; Argentin

Conversations on Race

More students of color enroll in U.S. colleges today than in previous decades due to changing demographics and rising aspirations. However, racist incidents on college campuses, persistent achievement gaps, and lack of faculty of color indicate there are race-related problems in higher education. Research shows that conversations on race increase cultural competency, promote empathy, reduce prejudice, improve relations among conflict group members, and develop critical awareness of privilege and oppression. Yet, educational leaders rarely engage in racial conversations to affect systems change. This paper examines the growing body of literature on the use of race conversations in schools and colleges. Additionally, it considers how race conversations might be aligned with systems thinking for dismantling structural racism within the higher education system

Dark Patterns: Effect on Overall User Experience and Site Revisitation

Dark patterns are user interfaces purposefully designed to manipulate users into doing something they might not otherwise do for the benefit of an online service. This study investigates the impact of dark patterns on overall user experience and site revisitation in the context of airline websites. In order to assess potential dark pattern effects, two versions of the same airline website were compared: a dark version containing dark pattern elements and a bright version free of manipulative interfaces. User experience for both websites were assessed quantitatively through a survey containing a User Experience Questionnaire (UEQ) and a System Usability Scale (SUS). Site revisitation i.e. users’ willingness to revisit a website was assessed qualitatively through semi-structured interviews. Dark pattern awareness was also investigated through the survey and interviews. For the UEQ, a significant difference was observed for Attractiveness. There was no significant difference observed for the rest of the scales, namely Perspicuity, Efficiency, Dependability Stimulation and Novelty. Additionally, there was no significant difference between the SUS scores of the two sites. Thus, dark pattern application was found to have no significant effect on overall user experience. Despite this, the bright website was found to have a higher rating for all scales of the UEQ as well as for the average SUS score compared to the dark website. The semi-structured interviews revealed that dark pattern also had no effect on site revisitation. Lastly, questions assessing dark pattern awareness revealed that the majority of participants were moderately aware of dark patterns despite not knowing the term

Living currency: The multiple roles of livestock in livelihood sustenance and exchange in the context of rural indigenous communities in southern Africa

Modern national and international monetary currencies continue to be the accepted universal media of exchange globally and, to a large extent, have expanded and displaced indigenous currencies and their roles within some community settings. There are, however, areas where indigenous currencies such as livestock (see Schneider, 1964), are considered as the most significant aspect of traditional economies. This paper explores the past and present roles of livestock as indigenous living currency amongst the Nguni and Shona people of southern Africa, mainly drawn from collaborative autoethnography. It further highlights how livestock currencies used alongside monetary ones have sustained and created multifaceted livelihood strategies of such rural area dwellers through intergenerational learning processes. This is against the background of the global economic instability ushered forth by modern economic practices (Karmin, 2008). The paper suggests that traditional 'living' currencies provide a more sustainable economy that enhances the socio-ecological resilience of indigenous rural communities in southern Africa. It also emphasises the need to recognise the coexistence of plural economies beyond the current monopoly of modern capitalist monetary economies