Influence of particle size and agglomeration in solid oxide fuel cell cathodes using manganite nanoparticles

In this work we studied the influence of particle size and agglomeration in the performance of solid oxide fuel cell cathodes made with nanoparticles of La0.8Sr0.2MnO3. We followed two synthesis routes based on the Liquid Mix method. In both procedures we introduced additional reagents in order to separated the manganite particles. We evaluated cathodic performance by Electrochemical Impedance Spectroscopy in symmetrical (CATHODE/ELECTROLYTE/CATHODE) cells. Particle size was tuned by the temperature used for cathode sintering. Our results show that deagglomeration of the particles, serves to improve the cathodes performance. However, the dependence of the performance with the size of the particles is not clear, as different trends were obtained for each synthesis route. As a common feature, the cathodes with the lowest area specific resistance are the ones sintered at the largest temperature. This result indicates that an additional factor related with the quality of the cathode/electrolyte sintering, is superimposed with the influence of particle size, however further work is needed to clarify this issue. The enhancement obtained by deagglomeration suggest that the use of this kind of methods deserved to be considered to develop high performance electrodes for solid oxide fuel cells.Fil: Martinelli, Hernán. Comisión Nacional de Energía Atómica. Centro Atómico Constituyentes; ArgentinaFil: Lamas, Diego Germán. Universidad Nacional de San Martín. Escuela de Ciencia y Tecnología; Argentina. Comisión Nacional de Energía Atómica. Centro Atómico Constituyentes; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Leyva, Ana G. Comisión Nacional de Energía Atómica. Centro Atómico Constituyentes; Argentina. Universidad Nacional de San Martín. Escuela de Ciencia y Tecnología; ArgentinaFil: Sacanell, Joaquin Gonzalo. Comisión Nacional de Energía Atómica. Centro Atómico Constituyentes; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Análisis cristalográfico e isotópico de granizos precipitados el 29-1-76 en la provincia de Mendoza

Se estudió 11 granizos de una misma tormenta. El análisis de la orientación permitió establecer que la mayor parte de los granizos se han formado en condiciones de crecimiento seco para temperaturas del depósito entre 0°C y -10°C y la temperatura del aire entre -15°C y -20°C. Supuestas estas condiciones se utilizaron los valores de la superficie media y longitud media de los cristales para evaluar la temperatura en las zonas de la nube en las que se han formado. A partir de estos datos y de los que se obtuvieron de la aplicación de un modelo de nube (de ascenso adiabático y Hirsh) se trazaron las posibles trayectorias de los granizos. Para dos de los granizos se determinó el contenido de deuterio y el resultado se interpretó aplicando a la nube el modelo de ascenso adiabático.We studied 11 hailstones from the same store. On the basis of the crystal orientation analysis, it was established that most hailstones were formed in dry growth conditions at deposit temperatures between 0°C and -10°C and air temperatures between ~15 °C and -20°C. Assumíng these conditions, the mean surface area and the mean length of the crystals were used to evalúate the temperature of the cloud zones where the hailstones were formed. On the basis of these datas and of those obtained from the application of the cloud model (of adiabatic ascent and Kirsch) the possible trajectories of the hailstones were drawn. For two of the hailstones, the deuterium content was determined, and the result was interpreted applying to the cloud the model of adiabatic ascentAsociación Argentina de Geofísicos y Geodesta

Current Approaches and Controversies: Legalization and Non-legalization of Drugs

When a critical analysis to date has made of, the historical aspects related to the topic of drugs, we could distinguish the existence of contrary positions regarding the possibility of legalizing them or not legalizing them. This dilemma is a very topical and important issue since opting for one position or another has economic, political and social implications that are necessary to keep track of. Therefore, the present study aims to; evaluate the advantages and disadvantages that would imply the legalization and non-legalization of drugs. Scientific journals from five years ago have consulted to date, theses and dissertations on the subject, digital and printed books that appear in libraries. Personal communication has made with researchers in the area of ​​addictions. The main results were that the legalization of drugs is very dangerous for society due to its highly addictive and harmful effects on human beings. Likewise, specialists in addictions affirm that legalization can send the wrong message that consuming marijuana and other illegal drugs does not represent risks, which in turn can generate the wrong perception of safety and promote the promotion of consumption. In conclusion, the legalization would not mean the disappearance of the current drug lords, since prices would fall, but this would have compensated with a higher demand, which would increase the sales-consumption volume

Diagnóstico sobre las bacterias rizosféricas asociadas al cultivo de caña de azúcar (Saccharum spp.)

Objective: Characterize the presence of rhizobacteria associated with three varieties of sugar cane: 9640 ATMEX, MEX 69-290 and the MEX SFC 9546, cultivated in the area of supplying the Pdte. Benito Juarez sugar mills (PBJ). Desing/methodology/approach: Three sites were selected for sampling by variety where soil samples were collected from 0 to 30 cm depth. For the isolation of the bacteria are followed by the serial dilution technique by viable. Results:The rhizosphere of the variety ATMEX-9640 presented the greatest number of CFU g-1. Ten of the 26 strains demonstrated capabilities of biological nitrogen fixation (BNF) or solubizacion of phosphorus (SP). Eight of them carried FBN already that degrade the malic acid in the NFb. Five are considered within the group of phosphorus solubilizing bacteria (BSP), because they solubilize the calcium phosphate of Pikovskaya medium. Limitations on study/implications: It was not possible to determine the production of AIA in the strains that grew in the Soya Tripticasa Broth medium. Findings/conclusions: The molecular identification revealed that these bacteria belong to the group of plant growth promoting rhizobacteria (PGPR) belonging Microbacterium, Bacillus y Paenibacillus genera present in the soil Cambisol Fluvic Éutric of the PBJ sugar mills.Objetivo: Evaluar la presencia de rizobacterias asociadas a tres cultivares de caña de azúcar: ATMEX 9640, MEX 69-290 y MEX SFC 9546, cultivados en la zona de abastecimiento del Ingenio Pdte. Benito Juárez (IPBJ). Diseño/Metodología/Aproximación: Se seleccionaron tres sitios de muestreo por cultivar donde se colectaron muestras de suelo de 0 a 30 cm de profundidad. Para el aislamiento de las bacterias se siguió la técnica de dilución seriada por cuenta viable. Resultados: La rizósfera del cultivar ATMEX 9640 presento el mayor número de UFC g-1. 10 de las 26 cepas manifestaron capacidades de fijación biológica de nitrógeno (FBN) o solubización de fósforo (SP). Ocho de ellas llevaron a cabo FBN ya que degradan el ácido málico en el medio NFb. Cinco se consideran dentro del grupo de bacterias solubilizadoras de fósforo (BSF), ya que solubiliza el fosfato de calcio del medio Pikovskaya. Limitaciones del estudio/implicaciones: No fue posible determinar la producción del AIA en las cepas que crecieron en el medio Caldo Tripticasa de Soya. Hallazgos/conclusiones: La identificación molecular reveló que estas bacterias corresponden al grupo de rizobacterias promotoras del crecimiento vegetal del genero Microbacterium, Bacillus y Paenibacillus sp presentes en el suelo Cambisol Fluvico Éutrico del IPBJ

Distribution pattern of psoriasis, anxiety and depression as possible causes of sexual dysfunction in patients with moderate to severe psoriasis

BACKGROUND: Psoriasis may significantly impair sexual function. Depression and organic factors appear to play a key role in this relation. However, beyond genital psoriasis, the importance of the disease's distribution patterns has not been considered. OBJECTIVES: To research sexual function in psoriasis patients and investigate the roles of anxiety, depression and psoriasis' distribution patterns in sexual dysfunction. METHODS: A comparative study matched for sex and age was performed. Eighty patients with moderate to severe psoriasis and 80 healthy controls were included. The participants completed the Massachusetts General Hospital-Sexual Functioning Questionnaire, the Hospital Anxiety and Depression Scale, and the Self-Administered Psoriasis Area and Severity Index. RESULTS: Psoriasis was associated with sexual dysfunction, odds ratio=5.5 (CI 95% 2.6-11.3; p<0.001). Certain distribution patterns of psoriasis, involving specific body regions, were associated with an increase in sexual dysfunction in the group presenting the disease, odds ratio 7.9 (CI 95% 2.3-33.4; p<0.001). Multivariate logistic regression analysis identified anxiety and depression, and the involvement of these specific areas, as possible independent risk factors for sexual dysfunction in patients with moderate to severe psoriasis. CONCLUSION: This study identifies body areas potentially related to sexual dysfunction, independently of anxiety and depression, in psoriasis patients. The results suggest that the assessment of sexual dysfunction and the involvement of these body areas should be considered as disease severity criteria when choosing the treatment for psoriasis patients

Análisis cristalográfico e isotópico de granizos precipitados el 29-1-76 en la provincia de Mendoza

Se estudió 11 granizos de una misma tormenta. El análisis de la orientación permitió establecer que la mayor parte de los granizos se han formado en condiciones de crecimiento seco para temperaturas del depósito entre 0°C y -10°C y la temperatura del aire entre -15°C y -20°C. Supuestas estas condiciones se utilizaron los valores de la superficie media y longitud media de los cristales para evaluar la temperatura en las zonas de la nube en las que se han formado. A partir de estos datos y de los que se obtuvieron de la aplicación de un modelo de nube (de ascenso adiabático y Hirsh) se trazaron las posibles trayectorias de los granizos. Para dos de los granizos se determinó el contenido de deuterio y el resultado se interpretó aplicando a la nube el modelo de ascenso adiabático.We studied 11 hailstones from the same store. On the basis of the crystal orientation analysis, it was established that most hailstones were formed in dry growth conditions at deposit temperatures between 0°C and -10°C and air temperatures between ~15 °C and -20°C. Assumíng these conditions, the mean surface area and the mean length of the crystals were used to evalúate the temperature of the cloud zones where the hailstones were formed. On the basis of these datas and of those obtained from the application of the cloud model (of adiabatic ascent and Kirsch) the possible trajectories of the hailstones were drawn. For two of the hailstones, the deuterium content was determined, and the result was interpreted applying to the cloud the model of adiabatic ascentAsociación Argentina de Geofísicos y Geodesta

Nanostructured LnBaCo2O6− (Ln = Sm, Gd) with layered structure for intermediate temperature solid oxide fuel cell cathodes

In this work, we present the combination of two characteristics that are beneficial for solid oxide fuel cell (SOFC) cathodic performance in one material. We developed and evaluated for the first time nanostructured layered perovskites of formulae LnBaCo2O6-d with Ln = Sm and Gd (SBCO and GBCO, respectively) as SOFC cathodes, finding promising electrochemical properties in the intermediate temperature range. We obtained those nanostructures by using porous templates to confine the chemical reagents in regions of 200-800 nm. The performance of nanostructured SBCO and GBCO cathodes was analyzed by electrochemical impedance spectroscopy technique under different operating conditions using Gd2O3-doped CeO2 as electrolyte. We found that SBCO cathodes displayed lower area-specific resistance than GBCO ones, because bulk diffusion of oxide ions is enhanced in the former. We also found that cathodes synthesized using smaller template pores exhibited better performance