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Search Results: 1 - 10 of 468280 matches for " J.L. González-Carrasco "
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Detection of metallic cylindrical inclusions by thermoelectric coupling
H. Carreon,J.L. González-Carrasco
Revista mexicana de física , 2012,
Abstract: In this paper, we present a technique that can give information on surface metallic inclusions embedded in a host material, i.e. by the magnetic sensing of local thermoelectric currents produced when a temperature gradient is established in the material. These thermoelectric currents generate flux magnetic densities that are detected by a highly sensitive magnetometer. A comparison between reported analytical results with experimental data of the magnetic field produced by thermoelectric currents around surface-breaking cylindrical tin inclusions in copper under external thermal excitation for different lift-off distances between the sensor and the surface of the specimen is presented. The diameter of the inclusions varied from 4.76 to 12.7 mm at different lift-off distance magnetometer probe and the specimen 1 to 8 mm respetively. A fairly modest 1.46±C/cm temperature gradient in the specimen produced magnetic flux densities ranging from 60 to 1460 nT.
Caracterización de la superaleación ODS MA 956 para aplicaciones biomédicas
Escudero, M. I.,Ruiz, J.,González-Carrasco, J. L.,Chao, J.
Revista de Metalurgia , 1998,
Abstract: Since the MA 956 was proposed as a possible new biomaterial due to its good corrosion resistance values in physiological fluids a long way, still not finished, has been done. An exhaustive characterization of this alloy at room temperature has been developed. The technological objectives are well established: the possible use of this material for biomedical applications as hip or knee prostheses and as dental implants. The study was performed comparing the results of this alloy with the materials used nowadays as surgical implants, i.e., titanium alloys and polyethylene. Desde que la MA 956 fue propuesta como posible nuevo biomaterial en base a su buena resistencia a la corrosión frente a sueros fisiológicos, un largo camino, aún sin finalizar, se ha recorrido, en el que se ha llevado a cabo una caracterización exhaustiva de esta aleación a temperatura ambiente con fines tecnológicos bien definidos: su posible uso en aplicaciones biomédicas, bien sea como prótesis de cadera o de rodilla y para implantes dentales. Los estudios se han llevado a cabo comparando esta aleación con los materiales más comúnmente utilizados en implantes ortopédicos como aleaciones de titanio y polietileno.
Estudio de la cinética de oxidación de la superaleación MA 956 M
García-Alonso, C.,González-Carrasco, J. L.,Escudero, M. L.
Revista de Metalurgia , 1998,
Abstract: This work deals with the oxidation kinetics of the MA 956 superalloy in the temperature range of 800-1,200°C for up to 200 h exposure. During oxidation the alloy develops a fine, compact and very well adhered α-alumina layer, the thickness of which increases with increasing time and temperature. The oxidation kinetics obeys a subparabolic type behaviour. The scale growth seems to occur by two different oxidation mechanisms; above 1,050°C, the oxidation process would be controlled by α-alumina, and below 900°C by γ-alumina. Se estudia la cinética de oxidación de la superaleación MA 956 en el intervalo de temperaturas 800-1.200°C durante tiempos de tratamiento de hasta 200 h. Durante la oxidación, se forma una capa de alúmina fina, densa y muy bien adherida cuyo espesor aumenta al aumentar el tiempo y la temperatura. La cinética de oxidación puede describirse mediante una ley de tipo subparabólico. El crecimiento de la capa de alúmina en el intervalo de temperaturas estudiado parece estar controlado por dos mecanismos distintos; por encima de 1.050°C se forma alúmina α y por debajo de los 900oC alúmina γ.
Efecto del pH ácido y de la desaireación del medio en el comportamiento frente a la corrosión de la MA 956 preoxidada
García-Alonso, M. C.,Escudero, M. L.,González-Carrasco, J. L.,Clemente, C.
Boletín de la Sociedad Espa?ola de Cerámica y Vidrio , 2000,
Abstract: The lifetime of implants is affected by the aggressivity of the physiological medium, which mainly results from the relatively high concentration of ion chlorides. There are, however, other transient situations that may enhance the aggressivity of the environment in the adjacent zones to the implant. For example, during the first days of the implantation is rather frequent to get bruises, inflammation, and even infections. These modifications could dramatically influence the corrosion behaviour and decrease the life expectancy of the implant. In this work the corrosion behaviour of the MA 956, which has been proposed as a new biomaterial, is investigated under experimental conditions of low pH and deareation, which simulate the most typical medical complications in service. Además del contenido en iones cloruro que ya hacen del medio fisiológico un entorno corrosivo, en la vida de un implante se producen situaciones transitorias que pueden provocar cambios locales del medio en torno al implante. En los primeros días de la implantación de un biomaterial es relativamente frecuente que se produzcan hematomas, con bajada en el valor del pH, inflamación e incluso infección. Estas situaciones químicas cambiantes, aunque en general son transitorias pueden modificar drásticamente el comportamiento a corrosión de un biomaterial y por tanto afectar negativamente a la vida en servicio de las prótesis. En este trabajo se presenta el comportamiento a corrosión de la superaleación MA 956 con capa de alúmina, en suero fisiológico, en condiciones de bajo pH y desaireación para simular la posibilidad de hematomas, inflamación e infección de los tejidos que rodean la prótesis, dado que esta superaleación está propuesta como nuevo biomaterial.
Debería realizar la tesis doctoral?: una retrospectiva compartida
González Geraldo, J.L.
Ensayos : Revista de la Facultad de Educacion de Albacete , 2010,
Abstract: El presente artículo desnuda el proceso de tesis doctoral, a la luz del incipiente Espacio Europeo de Educación Superior (EEES), a través de enfoque en el que el propio autor es, al mismo tiempo, la muestra. A través de tres partes claramente diferenciadas, se expondrán los pasos que conforman el proceso general de investigación de una tesis doctoral para, después, comprobar su disección desde un doble prisma: externo e interno. Las reflexiones que deriven de su lectura deberían de ser de especial interés para futuros doctorandos y directores de tesis, pues muestran el inicio, desarrollo y gestación de una tesis que, objetivamente, puede ser considerada como una buena práctica para comenzar, o al menos plantearse realizar, una tesis doctoral, especialmente, en relación con el ámbito educativo.
Instructional differences and differential item functioning: Agreement between the Mantel-Haenszel and the logistic regression
J.L. Padilla,A. González,C. Pérez
Psicológica , 1998,
Abstract:
Primary Productivity and Biomass of Size-Fractionated Phytoplankton in an Upwelling Area, Bahía de Mejillones (23oS, Chile), during and after the 1997-1998 El Ni o
J.L Iriarte,H. E González
Investigaciones Marinas , 2002,
Abstract:
Niveles de lisina y treonina digestible en dietas sorgo-pasta de soya para cerdos en crecimiento
López,M.; Figueroa,J.L.; González,M.J.; Miranda,L.A.; Zamora,V.; Cordero,J.L.;
Archivos de Zootecnia , 2010, DOI: 10.4321/S0004-05922010000200006
Abstract: was evaluated the effect of digestible lysine and threonine supplemented to sorghum-soybean meal diets for growing pigs on growth performance, carcass characteristics, and plasma urea nitrogen concentration (nup). in experiment 1, five dietary digestible lysine levels (0.67, 0.75, 0.83, 0.91 and 0.99%) were evaluated during four weeks. fifty barrows with 22.34 ± 3.45 kg of initial weight were used. in experiment 2 five dietary digestible threonine levels (0.42, 0.47, 0.52, 0.57 and 0.62%) were evaluated during six weeks. fifty pigs (25 barrows and 25 gilts) with 24.02 ± 3.73 kg of initial weight were used. pigs were alloted in a completely randomized design with five replicates of two pigs per experimental unit. the analyzed variables were as follows: average daily feed intake (cda), average daily gain (gdp), feed:gain ratio (ca), fat free lean gain (gcm), final body weight (pf), backfat thickness (gd), lean meat percentage (%cm), longissimus muscle area (aml), and plasma urea nitrogen concentration (nup). the cda, gdp and ca were recorded weekly and analyzed with the proc mixed procedure of sas; the variables obtained at the end of the experiment were analyzed with glm procedure. the means comparison was performed with tukey test; and orthogonal contrasts were applied to detect linear, quadratic or cubic effects. the best digestible lysine level for cda and gdp was 0.75%; for ca was 0.91%; and for pf was 0.99%. the orthogonal contrasts analysis showed a cubic effect of digestible lysine on cda; a lineal effect on ca; and a quadratic effect on aml, %cm, and nup. the digestible threonine levels did not affect growth performance, nor carcass characteristics; they just linearly reduced nup as digestible threonine levels increased. the barrows also reduced nup as the level of dietary digestible threonine increased. these results indicate that the level of digestible lysine affects differently growth performance, carcass characteristics and plasma urea nitrogen concentra
Necesidades en las enfermedades raras durante la edad pediátrica
Gaite,L.; García Fuentes,M.; González Lamu?o,D.; álvarez,J.L.;
Anales del Sistema Sanitario de Navarra , 2008,
Abstract: all rare diseases present a common set of challenges to the sufferers and their families: diagnosis, dealing with symptoms, health information, obtaining helpful medical care, availability of medications, disability and emotional impact. children with rare disorders are an important population from health care services, and social services perspectives, and families are providing long-term care for these chronically ill children. the impact of rare disorders in children is far-reaching, extending beyond the child to all those with whom he/she has contact. multiple facets of life are affected including social an family relationships, economical well-being and activities of daily living. the assessment of needs for rare disorders treatment is a critical step in providing high quality care and achieving patients? and families? satisfaction. findings from different studies show that people with rare diseases have medical and social needs. social needs are becoming more relevant in developed countries where health care services, even with limitations, have greater availability than social services. furthermore, it seems that health care and social services for persons with rare diseases need to be improved to address the patients? needs and to provide better support to families. validated tools with good psychometric porperties are still needed to assess quality of care on the basis of patients and family needs.
Unconventional magnetic properties of cuprates
González, J.L.;Caixeiro, E.S.;Mello, E.V.L. de;
Brazilian Journal of Physics , 2003, DOI: 10.1590/S0103-97332003000400025
Abstract: recently experiments on high critical temperature superconductors have shown that the doping levels and the superconducting gap are usually not uniform properties but strongly dependent on their positions inside a given sample. we show here that the large diamagnetic signal above the critical temperature tc and the unusual temperature dependence of the upper critical field hc2 with the temperature can be explained taking the inomo-geneities and a distribution of different local critical temperatures into account.
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