Thermally Conductive Polyethylene/Expanded Graphite Composites as Heat Transfer Surface: Mechanical, Thermo-Physical and Surface Behavior.

Composites of high-density polyethylene (HDPE) and expanded graphite (EG) are prepared for heat exchangers in multi-effect distillation (MED) desalination. At 50 wt.% EG loading, the thermal conductivity of HDPE was increased by 372%. Moreover, the surface wettability of the HDPE/EG composite was enhanced by corona and RF plasma treatment as demonstrated by the increase in surface free energy from 28.5 mJ/m2 for untreated HDPE/EG to 55.5 and 54.5 mJ/m2 for HDPE/EG treated by corona and RF plasma, respectively. This enhanced surface wettability was retained over a long time with only a 9% and 18% decrease in RF and corona plasma-treated samples' surface energy after two months. The viscoelastic moduli and the complex viscosity profiles indicated that EG content dictates the optimum processing technique. At loading below 30 wt.%, the extrusion process is preferred, while above 30 wt.% loading, injection molding is preferred. The plasma treatment also improved the HDPE/EG composite overall heat transfer coefficient with an overall heat transfer coefficient of the composite reaching about 98% that of stainless steel. Moreover, the plasma-treated composite exhibited superior resistance to crystallization fouling in both CaSO4 solution and artificial seawater compared to untreated composites and stainless-steel surfaces.

Contribuciones de la Psicología de la Liberación a la Integración de la Población Inmigrante / Contributions of Liberation Psychology to the Integration of the Immigrant Population

La migración es una dimensión inherente a la conducta humana desde el comienzo de la humanidad. Sin embargo, los éxodos actuales de personas empobrecidas hacia las zonas más opulentas del planeta representan nuevos desafíos que necesitan ser explorados con nuevas perspectivas y aproximaciones. La psicología de la liberación puede ayudar a dar respuesta a estos desafíos. Por un lado, permite explicar el sufrimiento de personas desplazadas e inmigrantes en términos de experiencias opresivas de vida impuestas por grupos que pretenden perpetuar y aumentar sus privilegios. Por otro, permite conocer cómo los inmigrantes confrontan y superan condiciones de injusticia, destruyen su posición de oprimidos, fortalecen lazos con otros grupos y llevan a cabo acciones colectivas para asegurar cohesión social y cooperación en los contextos de recepción y logran equitativas relaciones multiculturales. Este artículo describe las iniciativas que ha llevado a cabo CESPYD (Coalición para el Estudio de la Salud, el Poder y la Diversidad) para abordar en profundidad estos aspectos. Primero, discutimos las dificultades que la perspectiva dominante de la psicología de la aculturación tiene para abordar los desafíos de las nuevas migraciones. Complementariamente, proponemos la psicología de la liberación como un adecuado enfoque para completarla perspectiva tradicional. A continuación, redefinimos los conceptos de integración y competenciacultural como procesos de empoderamiento psicopolítico y las organizaciones de base comunitaria y las organizaciones sanitarias como escenarios comunitarios empoderadores. Finalmente, este artículo propone algunas direcciones de investigación que pueden ser abordadas desde este enfoque (AU)

Mobility is a human dimension that has been a part of human behaviour since humanity began. However, the actual exodus of impoverished people to the more opulent zones of the planet represents new challenges that need to be explored with new perspectives and approaches. Liberation psychology can assistin answering these challenges. On one hand, it permits an explanation of displaced people and poor immigrants’human suffering in terms of the life experiences oppressively imposed on them by other human groups as a means to maintain privileges. On the other hand, it allows knowing how immigrants confrontand overcome unjust conditions, destroy their position as oppressed, strengthen bonds with other groups,and carry out actions as a means to forge cohesion and cooperation in the contexts of reception and toachieve equitable multicultural international relations. This paper describes the initiatives that we have achieved in CESPYD for the purpose of studying these aspects in depth. First we discuss the difficulties that the dominant perspective of acculturation psychology poses in tackling the challenges that new migration represents. Additionally, we suggest liberation psychology as an adequate focus to complete a traditional perspective. Furthermore, we redefine concepts of integration and cultural competency as processes of psychopolitical empowerment and the community-based organizations and health organizations as empowering community settings. Finally, this paper proposes some research directions that can broaden its focus (AU)