Reversible operation performance of microtubular solid oxide cells with a nickelate-based oxygen electrode

This paper describes the reversible operation of a highly efficient microtubular solid oxide cell (SOC) with a nickelate-based oxygen electrode. The fuel cell was composed of a microtubular support of nickel and yttria stabilized zirconia (Ni-YSZ), an YSZ dense electrolyte, and a double oxygen electrode formed by a first composite layer of praseodymium nickelate (PNO) and gadolinium-doped ceria (CGO) and a second one of PNO. A good performance of the cell was obtained at temperatures up to 800 °C for both fuel cell (SOFC) and electrolysis (SOEC) operation modes, specially promising in electrolysis mode. The current density in SOEC mode at 800 °C is about -980 mA cm-2 at 1.2V with 50% steam. Current density versus voltage curves (j-V) present a linear behavior in the electrolysis mode, with a specific cell area resistance (ASR) of 0.32 O cm-2. Durability experiments were carried out switching the voltage from 0.7V to 1.2V. No apparent degradation was observed in fuel cell mode and SOEC mode up to a period of about 100 h. However, after this period especially in electrolysis mode there is an accumulated degradation associated to nickel coarsening, as confirmed by SEM and EIS experiments. Those results confirm that nickelate based oxygen electrodes are excellent candidates for reversible SOCs. © 2019 Hydrogen Energy Publications LL

Lanthanide nickelates for their application on Solid Oxide Cells

High-temperature technologies like solid oxide cells (SOC) have been employed to provide power-to-fuel and vice versa for energy conversion and storage. These technologies are a work in progress due to durability and compatibility issues between components at high temperatures. For this reason, the pursuit of optimal physical, mechanical, and chemical properties of SOC materials at lower temperatures has become more diligent. Finding suitable air electrodes has become one of the more notable obstacles to complete implementation in the industry. One of the most recent alternatives is the use of lanthanide nickelates with the Ruddlesden-Popper (RP), Lnn+1NinO3n±1 (Ln = La, Nd or Pr), and perovskite, LnNiO3-δ, structures. These materials present fast ionic and electronic transport, as well as flexible oxygen stoichiometry that makes them compelling for this purpose. As part of an ongoing study on alternative air electrode advanced materials, this review is focused on documenting the relevant findings of RP nickelates over the years, especially focusing on the current status in research and development while comparing the electrochemical performance of nickelate air electrodes

A hindcast simulation of Arctic and Antarctic sea ice variability, 1955-2001

A hindcast simulation of the Arctic and Antarctic sea ice variability during 1955-2001 has been performed with a global, coarse resolution ice-ocean model driven by the National Centers for Environmental Prediction/National Center for Atmospheric Research reanalysis daily surface air temperatures and winds. Both the mean state and variability of the ice packs over the satellite observing period are reasonably well reproduced by the model. Over the 47-year period, the simulated ice area (defined as the total ice-covered oceanic area) in each hemisphere experiences large decadal variability together with a decreasing trend of ∼1% per decade. In the Southern Hemisphere, this trend is mostly caused by an abrupt retreat of the ice cover during the second half of the 1970s and the beginning of the 1980s. The modelled ice volume also exhibits pronounced decadal variability, especially in the Northern Hemisphere. Besides these fluctuations, we detected a downward trend in Arctic ice volume of 1.8% per decade and an upward trend in Antarctic ice volume of 1.5% per decade. However, caution must be exercised when interpreting these trends because of the shortness of the simulation and the strong decadal variations. Furthermore, sensitivity experiments have revealed that the trend in Antarctic ice volume is model-dependent

Dengue y otros arbovirus en Argentina: panorama general y el cambio global

Las arbovirosis constituyen problemas crecientes de salud en el mundo tropical y subtropical. Particularmen­te, los Flavivirus transmitidos por mosquitos proveen algunos de los ejemplos más importantes de enferme­dades emergentes o reemergentes de significancia global. En las últimas décadas se ha registrado en Argentina la reemergencia del dengue luego de 81 años sin notificación de casos afectando inclusive provin­cias del área central de clima templado, la detección inédita de brotes epidémicos de enfermedad neurológica por el virus de la Encefalitis de San Luis en varias provincias, la introducción y diseminación del virus del Nilo Occidental y la reemergencia de la Fiebre Amarilla Selvática, luego de 42 años, generando algunos casos humanos e intensas epizootias en primates no humanos del noreste del país. Las enfermedades pro­ducidas por los Flaviwirus son zoonosis que dependen de especies animales más que del hombre para su mantenimiento en la naturaleza con la notable excepción de los virus dengue que se mantienen casi exclu­sivamente en circulación en los grandes centros urbanos donde el hombre actúa como reservorio viral. Los factores macrodeterminantes de la transmisión del dengue se clasifican en ambientales (latitud, humedad relativa, temperatura, otros); sociales (densidad de población, características de las viviendas, abasteci­miento de agua, entre otros) y estado socioeconómico de la población. Entre los factores microdeterminan- tes se destacan los dependientes del individuo, del agente y los relativos al vector (densidad de hembras adultas, frecuencia de alimentación, abundancia del vector, etc).Universidad Nacional de La Plat

Dengue y otros arbovirus en Argentina: panorama general y el cambio global

Las arbovirosis constituyen problemas crecientes de salud en el mundo tropical y subtropical. Particularmen­te, los Flavivirus transmitidos por mosquitos proveen algunos de los ejemplos más importantes de enferme­dades emergentes o reemergentes de significancia global. En las últimas décadas se ha registrado en Argentina la reemergencia del dengue luego de 81 años sin notificación de casos afectando inclusive provin­cias del área central de clima templado, la detección inédita de brotes epidémicos de enfermedad neurológica por el virus de la Encefalitis de San Luis en varias provincias, la introducción y diseminación del virus del Nilo Occidental y la reemergencia de la Fiebre Amarilla Selvática, luego de 42 años, generando algunos casos humanos e intensas epizootias en primates no humanos del noreste del país. Las enfermedades pro­ducidas por los Flaviwirus son zoonosis que dependen de especies animales más que del hombre para su mantenimiento en la naturaleza con la notable excepción de los virus dengue que se mantienen casi exclu­sivamente en circulación en los grandes centros urbanos donde el hombre actúa como reservorio viral. Los factores macrodeterminantes de la transmisión del dengue se clasifican en ambientales (latitud, humedad relativa, temperatura, otros); sociales (densidad de población, características de las viviendas, abasteci­miento de agua, entre otros) y estado socioeconómico de la población. Entre los factores microdeterminan- tes se destacan los dependientes del individuo, del agente y los relativos al vector (densidad de hembras adultas, frecuencia de alimentación, abundancia del vector, etc).Universidad Nacional de La Plat

Evaluación de la eficacia anti-arrugas de formulaciones cosméticas con un péptido anti-envejecimiento (Argirelina®)

The purpose of this research was to evaluate, by means of in vivo studies, the efficacy of new cosmetic active ingredients which effect of botox, called Argireline®), so that width and depth of wrinkles could be established. For this, it is prepared two formulations: an emulsion with an external aqueous phase for normal to dry skin, and a gel for oily skin. We likewise study the water content of the skin after the application of both formulas, as this must be one of the priority functions of facial treatments in general, as well as the level of satisfaction from the subjective point of view, fundamental for patients and their continuation of the treatment.After the designed tests, it is possible to verify that there is a remarkable diminution of the wrinkles size tested in each patient during the month of treatment. Besides, it is possible to review how the moisturizing capacity has been increased in all cases.At the end of the visual test, all the volunteers experienced a reduction in the depth of wrinkles, and from the subjective point of view, the appearance and elasticity of the skin were improved. Finally it is possible to conclude that Argireline® (acetyl hexapeptide-8 ) shows a great antiaging capacity in all the cases that have been studied and the tried compounds have increased moisturizing power.El propósito de esta investigación fue evaluar, mediante estudios in vivo, se podrían establecer la eficacia de nuevos ingredientes activos cosméticos que efecto del botox, llamado Argirelina®), de manera que la anchura y la profundidad de las arrugas. Para esto, se preparó dos formulaciones: una emulsión con una fase acuosa externa para piel normal a seca, y un gel para la piel grasa. Del mismo modo se estudia el contenido de agua de la piel después de la aplicación de ambas fórmulas, ya que esta debe ser una de las funciones prioritarias de tratamientos faciales en general, así como el nivel de satisfacción desde el punto de vista subjetivo, tanto para el enfermo y su continuación del tratamiento.Después de las pruebas diseñadas, es posible verificar que hay una notable disminución del tamaño de las arrugas a prueba en cada paciente durante el mes de tratamiento. Además, es posible revisar la forma en la capacidad de hidratación se ha incrementado en todos los casos.Al final de la prueba visual, todos los voluntarios experimentaron una reducción en la profundidad de las arrugas, y desde el punto de vista subjetivo, el aspecto y la elasticidad de la piel se han mejorado. Por último, es posible concluir que Argirelina® (hexapéptido acetil-8) muestra una gran capacidad antienvejecimiento en todos los casos que han sido estudiados y los compuestos probados se han incrementado poder hidratante

Direct-methane anode-supported solid oxide fuel cells fabricated by aqueous gel-casting

Direct methane Solid Oxide Fuel Cells (SOFCs) operated under catalytic partial oxidation (CPOX) conditions are investigated, focusing on the processing of the anode support and the anode deactivation caused by carbon deposition. Anode-supported SOFCs based on gadolinium-doped ceria (GDC) electrolyte, and NiO-GDC anode support were fabricated by the gel-casting method. Suitable aqueous slurries formulations of NiO–GDC were prepared, starting NiO-GDC nanocomposite powders, agarose as gelling agent and rice starch as pore former. Electrochemical and mechanical tests evidenced that the support of 550 ± 50 µm thickness and 10 wt% pore former is a good candidate for direct-methane SOFCs. The cells operating under stoichiometric conditions of CPOX reached a performance of 0.64 W·cm−2 at 650 ºC, a very close value to that measured under humidified hydrogen (0.71 W·cm−2). The best electrochemical stability of the cell is achieved at a CH4/O2 ratio of 2.5, showing no evidence of carbon deposition and reducing nickel re-oxidation significantly

Short communication: Effect of substituting hydroponic green barley forage for a commercial feed on performance of growing rabbits

[EN] The effect of replacing a commercial feed with hydroponic green barley forage (HGBF) was studied on productive performance and carcass yield of growing New Zealand rabbits. Four mixed diets based on a pelleted commercial feed (15.7% crude protein and 12.3% crude fi ber) were made by substituting wet HGBF (containing 16.1% dry matter, 2.18% crude protein and 2.36% crude fi ber) for the commercial feed (0, 10, 20 and 30%). Sixty-four rabbits, 35 d of age and with an average body weight of 917±9.7 (standard error) g were assigned to the 4 treatments and caged in groups of 4 rabbits (2 females and 2 males/cage). HGBF was grown for 15 d, and administered immediately after harvesting, including the radicular pad (roots and seed) and leaves. Feed intake and growth rate from 35 to 70 d of age were recorded. The rabbits were then slaughtered and the dressing-out percentage computed. Both dry matter feed intake and growth rate decreased linearly by 0.75±0.091 g/d (P<0.001) and 0.20±0.040 g/d (P<0.001) per unit of HGBF increase. Rabbits consumed daily all the HGBF offered 0, 2.3, 4.6 and 7.0 g DM for 0, 10, 20 and 30% substitution level, respectively. Feed conversion (average 3.26±0.026) and carcass yield percentage (average 58.1±0.32 %) were not affected by treatments. It was therefore concluded that replacing pelleted commercial feed by wet HGBF impaired growth performances.Morales, M.; Fuente, B.; Juárez, M.; Ávila, E. (2009). Short communication: Effect of substituting hydroponic green barley forage for a commercial feed on performance of growing rabbits. World Rabbit Science. 17(1):35-38. doi:10.4995/wrs.2009.668353817