Physicochemical and Electrical Properties of Praseodymium Oxides

The industrial research is continuously looking for novelties that could improve the applied processes, increasing the yields, lowering the costs, or improving the performances. In industrial electrochemistry, one more aspect is the stability of electrode materials, which is generally balanced by the catalytic activity: the higher the latter, the lower the former. A compromise has to be found, and an optimization is often the result of new ideas that completely change the way of thinking. Praseodymium-oxide-based cathodes have been proved to be quite interesting devices: the hydrogen evolution reaction is guaranteed by the presence of a noble metal (platinum and/or rhodium), while the stability and poisoning resistance seem to be strongly improved by the presence of lanthanide oxides

La configuración de las artes plásticas en Colombia 1940-1960, un proceso de tránsito estético y de cambio social

Sociólogo (a)Pregrad

A new approach to the analysis of vessel residence time distribution curves

Mathematical models for the evaluation of residence time distribution (RTD) curves on a large variety of vessels are presented. These models have been constructed by combination of different tanks or volumes. In order to obtain a good representation of RTD curves, a new volume (called convection diffusion volume) is introduced. The convection-diffusion volume allows the approximation of different experimental or numerical RTD curves with very simple models. An algorithm has been developed to calculate the parameters of the models for any given set of RTD curve experimental points. Validation of the models is carried out by comparison with experimental RTD curves taken from the literature and with a numerical RTD curve obtained by three-dimensional simulation of the flow inside a tundish. &nbsp

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The industrial research is continuously looking for novelties that could improve the applied processes, increasing the yields, lowering the costs, or improving the performances. In industrial electrochemistry, one more aspect is the stability of electrode materials, which is generally balanced by the catalytic activity: the higher the latter, the lower the former. A compromise has to be found, and an optimization is often the result of new ideas that completely change the way of thinking. Praseodymium-oxidebased cathodes have been proved to be quite interesting devices: the hydrogen evolution reaction is guaranteed by the presence of a noble metal (platinum and/or rhodium), while the stability and poisoning resistance seem to be strongly improved by the presence of lanthanide oxides

La escuela nacional de bellas artes 1920-1940: arte y conocimiento

La Escuela Nacional de Bellas Artes fue una de las instituciones de formación artística más importantes del siglo XX en Colombia. La historia que aquí se trata, aborda uno de los periodos más importantes de la plástica nacional como lo fueron los años entre 1920 a 1940. Por otro lado, esta Investigación tiene como objetivo, a partir de un trabajo empírico, entender cómo estudiantes, maestros, directores y comentaristas sobre el campo cultural y artístico colombiano, comprendían el proceso artístico, o en términos más generales cómo entendían el arte. Por tanto esta historia de la Escuela Nacional de Bellas Artes trata de entender los fenómenos artísticos como fenómenos del conocimiento.Abstract. The Escuela Nacional de Bellas Artes was one the most important institution of artistic teaching in Colombia in the last century. In the same way the period of 1920-1940 were very important years to understand the history of arts in this country. On the other hand whit empirical research, the objective understands how students, teachers and critics of art, comprehended the process of creation of art. The main question is how they understood the plastics arts. Therefore this history of Escuela Nacional de Bellas Artesis research about artistic phenomenon as problem of knowledgeMaestrí

A cohort study on acute ocular motility disorders in pediatric emergency department

Background: Acute ocular motility disorders (OMDs) in children admitted to Emergency Department (ED) represents a not so rare condition with a wide spectrum of different etiologies. The emergency physician must be skilled in rapidly identifying patients with potentially life threatening (LT) forms, requiring further diagnostic procedures. The aim of the study was to assess characteristics of children with acute Ocular Motility Disorders (OMDs), and to identify "red flags" for recognition of underlying life-threatening (LT) conditions. Methods: A retrospective cohort study evaluated children (2 months-17 years) admitted to a tertiary Emergency Department in 2009-2014. A subgroup analysis was performed comparing children with and without LT conditions. Results: Of 192 visits for OMDs, the isolated strabismus occurred most frequently (55.6%), followed by pupil disorders (31.8%), ptosis (5.2%) and combined OMDs (11.5%). The majority of acute OMDs involved no underlying LT conditions (n = 136) and most of them were infants or toddlers (50%). In a multivariable analysis, LT conditions included especially children over 6 years of age, increasing the odds ratio by 2% for each months of age (p = 0.009). LT etiologies were 16 times more likely in combined OMDs (p = 0.018), were over 13 times more likely to report associated extra-ocular signs/symptoms (p = 0.017) and over 50 times more likely to report co-morbidity (p = 0.017). Conclusion: OMDs are not an uncommon presentation at ED. Although most of them involve non-LT conditions, the ED physician should consider potential "red flags" for appropriate management of children such as age > 6 years, combined OMDs, extra-ocular symptoms and co-morbidity

Electrochemical disinfection of groundwater for civil use – An example of an effective endogenous advanced oxidation process

Lab-scale experiments using real groundwater were carried out using the CabECO® reactor system in order to evaluate its suitability for producing safe water, acceptable for civil purposes. Trials were carried out in discontinuous and in continuous mode, analyzing the influence of electrical and hydraulic process parameters on the quality of treated water. The use of highly boron-doped diamond electrodes in the reactor allowed the electrosynthesis of considerable amounts of ozone. Because of the relatively high amount of chloride in the groundwater samples, a mixture of HOCl/ClO- was also synthesized. Somewhat unexpectedly, the increase in the current density in the explored range 100 -1000 A m-2 was accompanied by an increase in the faradaic yield of the electrosynthesis of oxidants, which was more pronounced for ozone than for free chlorine. As reported in literature, the main radical intermediate in the relevant reactions is ●OH, which can lead to different oxidation products, namely ozone and HOCl/ClO-. The electrolytic treatment also caused a decrease in the concentration of minor components, including NH4+ and Br-. Other byproducts were ClO3- and ClO4-, although their concentration levels were low. Moreover, due to alkali formation at the cathode surface, the precipitation of calcium and magnesium carbonates was also observed. In addition, the experimental investigation showed that even Pseudomonas aeruginosa and Legionella could be completely removed in the treated stream, due to the unique capacity of the reactor to synthesize biocidal agents like ozone, HOCl/ClO-, and chloramines. These effects were particularly evident during batch experiments.Lab-scale experiments using real groundwater were carried out using the CabECO® reactor system in order to evaluate its suitability for producing safe water, acceptable for civil purposes. Trials were carried out in discontinuous and in continuous mode, analyzing the influence of electrical and hydraulic process parameters on the quality of treated water. The use of highly boron-doped diamond electrodes in the reactor allowed the electrosynthesis of considerable amounts of ozone. Because of the relatively high amount of chloride in the groundwater samples, a mixture of HOCl/ClO− was also synthesized. Somewhat unexpectedly, the increase in the current density in the explored range 100–1000 A m−2 was accompanied by an increase in the faradaic yield of the electrosynthesis of oxidants, which was more pronounced for ozone than for free chlorine. As reported in literature, the main radical intermediate in the relevant reactions is [rad]OH, which can lead to different oxidation products, namely ozone and HOCl/ClO−. The electrolytic treatment also caused a decrease in the concentration of minor components, including NH4+ and Br−. Other byproducts were ClO3− and ClO4−, although their concentration levels were low. Moreover, due to alkali formation at the cathode surface, the precipitation of calcium and magnesium carbonates was also observed. In addition, the experimental investigation showed that even Pseudomonas aeruginosa and Legionella could be completely removed in the treated stream, due to the unique capacity of the reactor to synthesize biocidal agents like ozone, HOCl/ClO−, and chloramines. These effects were particularly evident during batch experiments

Dynamic, ecological, accessible and 3D Virtual Worlds-based Libraries using OpenSim and Sloodle along with mobile location and NFC for checking in

This paper proposes the implementation of a 3D virtual library, using open platforms such as OpenSimulator and Sloodle, applied to the integration of virtual learning environments. It also proposes their application to the creation of open libraries to share and disseminate the new dynamic nature of knowledge, in the understanding that 3D virtual worlds may contribute to the future of libraries as part of green initiatives to achieve an ecologic and sustainable planet