Reactivo de Lugol: Historia de su descubrimiento y aplicaciones didácticas

Our paper is a brief historical study of aqueous solutions of potassium iodide and iodine. It also analyzes why, in Biology and Medicine, these solutions are known as Lugol reactive. Moreover, we study their use for educational purposes to deepen in various topics such as redox reactions and the relationship between solubility and bond types

Glacial environment protection

Se presenta una revisión sintética del desarrollo de la regulación argentina en materia de preservación de glaciares y medio ambiente periglacial, incluyendo i) el marco jurídico general de protección de las aguas en Argentina; ii) los antecedentes de la Ley N° 26.639 de 2010 sobre protección de glaciares y medio ambiente periglacial; iii) la conflictividad generada entre la protección glacial y la minería, y vi) las principales cuestiones controvertidas de la aplicación de la Ley N° 26.639 de 2010.A synthetic review of the development of Argentina’s regulation concerning the preservation of glaciers and periglacial environment is presented, including: i) the general legal framework for water protection in Argentina; ii) the history of Law Nº 26.639 of 2010, on the protection of glaciers and periglacial environment; iii) the confl ict generated between glacial protection and mining protection; and iv) the main controversial issues of the implementation of Law No 26,639 of 2010.Fil: Martin, Liber Alexis. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza; Argentina. Universidad Nacional de Cuyo; ArgentinaFil: Pinto, Martín. Universidad Nacional de Cuyo; Argentina. Universidad de Mendoza; Argentina. Universidad del Aconcagua; Argentin

Una aproximación a la historia de la enseñanza de la Química universitaria en España

Se resume la historia de la enseñanza de la química en la Universidad española, desde mediados del siglo XIX hasta el presente, partiendo de la Ley Moyano de 1857, que permitió la creación de facultades de ciencias con una sección de química, y del nacimiento de la Institución Libre de Enseñanza, que influirá de forma importante hasta 1936. Se describen otros hitos, como la creación de la Junta para la Ampliación de Estudios e Investigaciones Científicas, la fundación del Instituto Nacional de Física y Química (conocido en la época como Instituto Rockefeller), o el reciente Proceso de Bolonia, así como una semblanza de algunos de los profesores más destacados de estas épocas

Modeling the heat transfer by conduction of nanocellular polymers with bimodal cellular structures

Nanocellular polymers are a new generation of materials with the potential of being used as very efficient thermal insulators. It has been proved experimentally that these materials present the Knudsen effect, which strongly reduces the conductivity of the gas phase. There are theoretical equations to predict the thermal conductivity due to this Knudsen effect, but all the models consider an average cell size. In this work, we propose a model to predict the thermal conductivity due to the conduction mechanisms of nanocellular materials with bimodal cellular structures, that is, with two populations of cells, micro and nanocellular. The novelty of our work is to consider not only the average cell size, but the cell size distribution. The predictions of the model are compared with the experimental conductivity of two real bimodal systems based on poly(methyl methacrylate) (PMMA), and it is proved that this new model provides more accurate estimations of the conductivity than the models that do not consider the bimodality. Furthermore, this model could be applied to monomodal nanocellular polymers. In particular, for monomodal materials presenting a wide cell size distribution and at low densities, the model predicts important variations in comparison with the current models in the literature. This result indicates that the cell size distribution must be included in the estimations of the thermal conductivity of nanocellular polymer

Factores que impiden aplicar una gestión de riesgos en la Empresa Constructora HISAC Contratistas S.R.L. - Trujillo

La presente tesis tiene como propósito identificar los factores negativos que impiden implementar una gestión de riesgos en la empresa constructora HISAC CONTRATISTAS S.R.L. De los cuales se escogió un proyecto, el cual será evaluado para poder identificar los factores negativos, en la implementación de una gestión de riesgos. Sé procederá a encuestar a los principales responsables de la ejecución de los proyectos seleccionados a evaluar, con el fin de identificar los factores negativos que impiden llevar a cabo una correcta implementación de una gestión de riesgos; es decir, se llevó a cabo la elaboración de una encuesta, la cual nos permitirá obtener datos reales, acerca del nivel de participación, conocimiento y compromiso; para llevar a cabo con éxito este proyecto. La propuesta más conveniente, debe ser puesta en marcha lo más pronto posible; sin perjudicar la economía de la empresa constructora HISAC CONTRATISTAS S.R.L; la cual debe ser fuente de evaluación de los proyectos a ejecutar en un futuro. Las recomendaciones y conclusiones que se elaborarán, van a permitir a otras empresas constructoras que trabajen con el estado, en poder identificar y poner en marcha una correcta gestión de riesgos.This thesis aims to identify the negative factors that prevent implementing a management of risks in the construction company HISAC CONTRATISTAS S.R.L. Of which was chosen a project, which will be evaluated to identify the negative factors in the implementation of risk management. I know will be interviewing those chiefly responsible for the implementation of the selected projects to evaluate, in order to identify negative factors that impede to carry out a correct implementation of a risk management; i.e., the elaboration of a survey, which will allow us to get real data, about the level of participation was conducted, knowledge and commitment; in order to successfully complete this project. The most suitable proposal, should be launched as soon as possible; without harming the economy of the construction company HISAC CONSTRATISTAS S.R.L; which should be source of evaluation of projects to implement in the future. The recommendations and conclusions that will be developed, they will allow other construction companies to work with the State, to identify and implement proper risk management.Tesi

Low-density PMMA/MAM nanocellular polymers using low MAM contents: Production and characterization

Low-density nanocellular polymers are required to take advantage of the full potential of these materials as high efficient thermal insulators. However, their production is still a challenging task. One promising approach is the use of nanostructured polymer blends of poly(methyl methacrylate) (PMMA) and a block copolymer poly(methyl methacrylate)-poly(butyl acrylate)-poly(methyl methacrylate) (MAM), which are useful for promoting nucleation but seem to present a severe drawback, as apparently avoid low relative densities. In this work, new strategies to overcome this limitation and produce low-density nanocellular materials based on these blends are investigated. First, the effect of very low amounts of the MAM copolymer is analysed. It is detected that nanostructuration can be prevented using low copolymer contents, but nucleation is still enhanced as a result of the copolymer molecules with high CO2 affinity dispersed in the matrix, so nanocellular polymers are obtained using very low percentages of the copolymer. Second, the influence of the foaming temperature is studied. Results show that for systems in which there is not a clear nanostructuration, cells can grow more freely and smaller relative densities can be achieved. For these studies, blends of PMMA with MAM with copolymer contents from 10 wt% and as low as 0.1 wt% are used. For the first time, the production strategies proposed in this work have allowed obtaining low density (relative density 0.23) nanocellular polymers based on PMMA/MAM blends. Graphical abstrac

Análise comparativa da qualidade de panificaçao e rendimento de graos entre tritórdeo hexaplóide e outros cereais de inverno

A duplicação cromossômica dos híbridos entre Hordeum chilense e Triticum turgidum conv. durum originou o tritórdeo hexaplóide (X Tritordeum Ascherson et Graebner), um novo cereal cujas características estão sendo avaliadas. Com o objetivo de obter maiores informações sobre o potencial do tritórdeo para a qualidade de panificação e componentes do rendimento de grãos, foi instalado em 1996 em Córdoba, Espanha, um experimento de campo com três repetições. O desempenho de três linhagens de tritórdeo foi comparado com o rendimento de duas variedades comerciais de trigo, duas de trigo duro e quatro de triticale. O conjunto de resultados indicou perspectivas do tritórdeo para o desenvolvimento de variedades altamente produtivas com aceitável qualidade de panificação, especialmente por se tratar de uma espécie nova e ainda pouco melhoradaChromosome duplication of hybrids between Hordeum chilense and Triticum turgidum conv. durum originated a new cereal, of which characteristics for cropping being evaluated, the hexaploid tritordeum (X Tritordeum Ascherson et Graebner). In order to have more information about breadmaking quality and grain yield components in tritordeum, are a field experiment with three replications was carried out during the growing season of 1996 in Córdoba, Spain. Performance of three tritordeum lines was compared with two varieties of wheat, two of durum wheat and four of triticale. Results allow to expect the development of high yielding varieties of tritordeum with acceptable breadmaking qualit

College radio as coaching professional. Analysis of the relationship between the degrees and Spanish university radio

La radio universitaria está sometida a una transformación constante. El auge de las tecnologías de la información y la comunicación ha permitido su evolución y modernización, así como la proliferación de nuevos perfiles profesionales. La presente investigación tiene por objeto analizar la vinculación existente de las emisoras universitarias españolas con las titulaciones pertinentes. Para ello, utilizaremos una metodología comparativa basada en el examen de descriptores y asignaturas específicas fundamentalmente de las titulaciones en Comunicación Audiovisual y Periodismo, además del Grado de Información y Comunicación, por las posibilidades que ofrecen estas emisoras para el desarrollo competencial de su alumnado. Como conclusión, se observan aún debilidades estructurales en el ámbito universitario, si bien se constatan posibilidades de futuro, ya que una radio universitaria constituye un lugar de convergencia entre la formación de los alumnos de diferentes titulaciones y la realidad, un medio polivalente que brinda la pertinencia de ser el primer contacto profesional de los estudiantes universitarios con el mundo laboral.College radio is subject to constant transformation. The rise of information and communications technologies has allowed its development and modernization as well as the proliferation of new professional profiles. This research aims to analyze the connection of the Spanish university stations with the relevant qualifications. To do this, we use a comparative methodology based on examination of descriptors and specific principal subjects of degrees such as Audiovisual Communication and Journalism, although we will be using other degrees that are acquiring more responsibilities in a radio station, such as the degree in Information and Documentation. In conclusion, structural weaknesses in the university environment are observed, but future possibilities are detected as well: A college radio station is a place of convergence between the training of students from different degrees and reality itself, a versatile medium that provides the relevance of being the first professional contact of college students with the labor market.peerReviewe