Mechanical properties of tungsten alloys with Y2O3 and titanium additions

In this research the mechanical behaviour of pure tungsten (W) and its alloys (2 wt.% Ti–0.47 wt.% Y2O3 and 4 wt.% Ti–0.5 wt.% Y2O3) is compared. These tungsten alloys, have been obtained by powder metallurgy. The yield strength, fracture toughness and elastic modulus have been studied in the temperature interval of 25 °C to 1000 °C. The results have shown that the addition of Ti substantially improves the bending strength and toughness of W, but it also dramatically increases the DBTT. On the other hand, the addition of 0.5% Y2O3, is enough to improve noticeably the oxidation behaviour at the higher temperatures. The grain size, fractography and microstructure are studied in these materials. Titanium is a good grain growth inhibitor and effective precursor of liquid phase in HIP. The simultaneous presence of Y2O3 and Ti permits to obtain materials with low pores presenc

Linear Dynamics and Control of a Kinematic Wobble–Yoke Stirling Engine

This paper presents a control systems approach for the modeling and control of a kinematic wobble–yoke Stirling engine. The linear dynamics of the Stirling engine are analyzed based on the dynamical model of the system, developed by these authors. We show that the Stirling engine can be viewed as a closed–loop system, where the feedback control law is given by the pressure variations in the pistons. Since the closed–loop system exhibits unstable dynamics, we design a pre–compensator to stabilize the displacements of the engine’s pistons, and an observer to estimate their piston velocities

La ciencia andaluza a golpe de ratón

El Sistema de Información Científica de Andalucía (SICA) es una ventana al conocimiento que se produce en nuestra comunidad autónoma. En 2010 ha comenzado el diseño de SICA2 que situará a esta plataforma en la vanguardia de la sistematización y la difusión de la investigació

Baja morbilidad en niños operados de nefrectomía con técnica laparoscópica transperitoneal de 3 puertos

ResumenAntecedentesAunque la nefrectomía laparoscópica actualmente se considera el estándar de oro en la cirugía renal del adulto, aún existe controversia de su papel en la población pediátrica. La nefrectomía laparoscópica ha demostrado ser un procedimiento efectivo y seguro comparado con el abordaje abierto.ObjetivoPresentar una serie de casos de pacientes pediátricos con diversas enfermedades renales, tratados con nefrectomía laparoscópica transperitoneal.Materiales y métodosIncluye 22 pacientes pediátricos sometidos a nefrectomía laparoscópica transperitoneal. Todos los casos se realizaron vía laparoscópica con abordaje transperitoneal usando 3 puertos.ResultadosTodos los riñones se removieron satisfactoriamente. El promedio de tiempo operatorio fue de 142min. En 21 de los 22 casos no hubo complicaciones que requirieran conversión cirugía abierta. Se inició dieta y deambulación el mismo día de la cirugía en todos los pacientes y se dio de alta a 20 de los 21 pacientes sin conversión a los 2 días postoperatorios.ConclusionesEn nuestra serie de casos reportamos el abordaje transperitoneal laparoscópico para nefrectomía usando una técnica con 3 puertos que puede ser usada con seguridad en la población pediátrica con los mismos resultados y seguridad que otros procedimientos laparoscópicos. Es una excelente alternativa a la cirugía abierta tradicional y debe ser considerada para disminuir el riesgo quirúrgico.AbstractBackgroundEven though laparoscopic nephrectomy is considered the gold standard in renal surgery in the adult, its role in the pediatric population is still a subject of debate. Laparoscopic nephrectomy has been shown to be a safe and effective procedure, compared with the open approach.AimTo present a case series of pediatric patients with different renal pathologies treated through transperitoneal laparoscopic nephrectomy.Material and methodsTwenty-two pediatric patients that underwent transperitoneal laparoscopic nephrectomy were included in the study. All of the cases underwent the 3-port transperitoneal laparoscopic approach.ResultsAll the kidneys were satisfactorily removed and the mean surgery duration was 142 min. There were no complications requiring conversion to open surgery in 21 of the 22 cases. Oral diet and ambulation were begun the same day of the surgery for all patients. Twenty of the 21 patients that did not require conversion were released on the second postoperative day.ConclusionsWe report herein on the transperitoneal laparoscopic approach for nephrectomy with the 3-port technique. It can be performed in the pediatric population with the same results and safety as other laparoscopic procedures and is an excellent alternative to traditional open surgery. This procedure should be considered for reducing surgical risk

Single neuron transient activity detection by means of tomography

From Twentieth Annual Computational Neuroscience Meeting: CNS*2011 Stockholm, Sweden. 23-28 July 2011(CA) and (ES) are supported by BFU2009-08473. (CA) and (PP) are partially supported by AYA2009-14212-05. (PP) is partially supported by TIN2010-21575-C02-01

Novel Ir1–xCoxO2 thin films: Growth and characterization

Ir1–xCoxO2 thin films have been prepared by reactive co–sputtering deposition at room temperature. Composition, structure, electronic properties and electric and magnetic behavior have been analyzed by different techniques including XRR, XRD, TEM microscopy, SQUID magnetometry, electrical resistivity and XAS spectroscopy. After annealing, an Ir1–xCoxO2 substitutional solid solution phase with rutile crystal structure was achieved for a wide Co-doping range 0 ≤ x ≤ 0.6. Starkly departing from the highly insulating behavior of CoO and Co3O4, the electrical resistivity at room temperature of our films is only slightly higher than that of IrO2. Likewise, our work shows that the magnetic response of the doped films is very similar to that of the paramagnetic parent IrO2. Neither ferromagnetism nor enhanced paramagnetism is observed. XAS spectra indicate a Co3+ oxidation state and, correspondingly, an oxidation state of ∼5+ for Ir ions in the polycrystalline Ir0.6Co0.4O2 film. By application of sum rules, a 13 % increase in the spin–orbit coupling is found despite the lattice shrinkage causes a detrimental bandwidth broadening

Estilo de vida y estado de nutrición en niños escolares

ResumenObjetivoRelacionar el estilo de vida y el estado de nutrición en escolares.MétodoEstudio correlacional, participaron 260 niños adscritos a la Clínica ISSSTE, elegidos aleatoriamente. Se utilizó el cuestionario sobre estilos de vida en la niñez y se valoró el peso y talla. Se obtuvo la aprobación de la Jefatura de Investigación del ISSSTE. En el análisis de datos se aplicó estadística descriptiva e inferencial.ResultadosParticiparon 137 niños y 123 niñas, con edades entre 6-12 años. Respecto al estado de nutrición, 5 de cada 10 de los participantes se encuentran en peso normal, 2 de cada 10 en sobrepeso y uno de cada 10 en obesidad y peso bajo. Sobre el estilo de vida 7 de cada 10 de los participantes se encontraron en riesgo bajo y 2 de cada 10 en riesgo mediano. Por otra parte, no se encontró relación entre el estilo de vida de los niños y su estado de nutrición (rs=0.038, p>0.05). Adicionalmente, se encontró que los niños con peso normal o bajo peso tienen mejores hábitos de sueño que los niños con sobrepeso u obesidad (U=3.79, p<0.001).ConclusionesEste estudio muestra indicios de que los aspectos vinculados con la dimensión psicocorporal y con uso del tiempo libre deberían indagarse a mayor profundidad, ya que fueron los que arrojaron cifras que ubican a los escolares en riesgo medio y alto.AbstractObjectiveTo explore the association between lifestyle and nutritional status among school children.MethodCorrelational study involving 260 children registered at an ISSSTE clinic, who were randomly selected. A questionnaire on childhood lifestyles was used; weight and height were also assessed. A project approval from the ISSSTE research committee was obtained. Descriptive and inferential statistics were used.Results137 boys and 123 girls with ages between 6 and 12 years old participated. In relation to the nutrition status, five out every ten have a normal weight; two out every ten are over weighted, and one out of every ten is obese or under weighted respectively. In relation to lifestyle, seven out of every ten participants have low risk; and two out of every ten have medium risk. On the other hand a relation between the lifestyle and nutritional status of the children was not found (rs=.038, p>0.05). Moreover, it was found that children with normal or low weights have better sleep habits in comparison to the children who are over weighted or obese U=3.79, p <.001).ConclusionsThis study suggests that issues related to the psychological and corporal dimensions, as well as the use of free time, should be further explored because they showed figures which place children within mid and high risks

Effect of fluvastatin therapy of the pattern of protein expression in monocytes of patients in primary antiphospholipid syndrome

Comunicaciones a congreso