Influencia de los efectos de segundo orden en piezas esbeltas sometidas a flexión

En este trabajo se presenta un cálculo analítico no lineal de las deformaciones y tensiones en piezas esbeltas sometids a flexión. Los resultados se comparan con los obtenidos por un método matricial "paso a paso", en el que los efectos de segundo orden se tienen en cuenta aplicando las cargas por etapas, y actualizando la geometría en cada etapa. Por último, se comparan los resultados de ambos métodos con los de un método matricial habitual, en una sola etapa

Aplicación de la fiabilidad estructural a piezas esbeltas en voladizo

La fiabilidad estructural tiene como objetivo el tratamiento racional de las incertidumbres existentes en los sistemas estructurales, así como el estudio de procedimientos que permitan valorar la seguridad de los mismos. El objeto de este artículo es la aplicación de la teoría de fiabilidad a elementos esbeltos en voladizo sometidos a flexión, considerando los efectos de segundo orden=The objetive of structural reliability is the rational treatment of ramdom phenomena in structural systems and also the study of the procedures for the assesment of its safety. This workadress the application of reliability theories to cantilever slender elements under bending taking account of second order effects

Formic Acid Ionization and Fragmentation by Multiphoton Absorption

Multiphoton absorption is an intensity dependent nonlinear effect related to the excitation of virtual intermediate states. In the present work, multiphoton ionization and dissociation of the formic acid molecule (HCOOH) by the interaction with photons from 532 Nd: YAG laser at different intensities are discussed, using different carrier gases. The induced fragmentation-ionization patterns show up to 17 fragments and dissociation channels are proposed. Some evidence of small clusters formation and conformational memory from the ratio of the detected products, CO+ and CO2+, on the light of the available results, it is possible to conclude that they arise from trans and cis formic acid. Our results are compared with those obtained in other laboratories under different experimental conditions, some of them show only partial agreement and differences are discussed. Following the Keldysh description it is possible, from our experimental parameters, characterize our results, in the multiphoton absorption regime

Synthesis of Ceramic Pigments by Non-Conventional Methods for New Ceramic Decoration Technologies

The ceramic tile industry increasingly commits to modernisation and implementation of new technologies in the decoration process. Current demands of advanced processes in this fi eld, such as rotational decoration, inkjet printing, PVD (physical vapour deposition), laser systems, etc., led to a great interest in developing ceramic pigments with controlled composition and microstructure. These pigments are thermally and mechanically stable in the production cycles, have reproducible and multifunctional properties, and meet ecological and economic demands. The research work in this fi eld made the ceramic sector dynamic and competitive with regard to opening new markets

Expression of B-nerve growth factor in rabbit male tract and seminal plasma

Nerve growth factor (NGF) has been recently identified as an ovulation inductor factor (OIF) in the seminal plasma (SP) (Ratto et al. PNAS 2012; 109:15042-7). The presence of OIF in rabbit has been suggested but this protein has not yet been identified. Our aim was to study the mRNA expression in the rabbit male reproductive tract and to identify the protein β-NGF in the SP

Quid: observatorio de medios

Medios de Comunicación y Derecho a la Información en Jalisco, consta de cinco partes: Medios de Comunicación y Estado; Medios Públicos de Jalisco; Medios Electrónicos de la Zona Metropolitana de Guadalajara; Transparencia en el estado; y Sociedad civil y Derecho a la Información. En estas secciones podrán encontrarse diversos artículos que documentan casos como las presuntas transgresiones del gobernador de Jalisco al artículo 134 constitucional (que hace referencia a la prohibición expresa que tienen los gobernantes para hacer promoción personal en medios de comunicación con recursos públicos); las donaciones que el gobierno del estado ha dado a instituciones como Televisa, TV Azteca o MTV; los cambios en el Sistema Jalisciense de Radio y Televisión; el surgimiento de la Asociación Mexicana del Derecho a la Información capítulo Jalisco; entre otros. Estos temas son muy importantes porque son coyunturas que dan pistas de cómo está conformado el sistema de comunicación de nuestro entorno.ITESO, A.C

150 años del descubrimiento del yacimiento cámbrico de Murero (Cadenas Ibéricas, NE España).

The lower-middle Cambrian palaeontological site of Murero (Cadenas Ibéricas, NE Spain) is a classical locality of the Cambrian in Europe. The site was first reported by the French geologist Edouard de Verneuil in 1862, and now it achieves 150 years of geological works contributing to a better knowledge of the Cambrian Period. Murero is an exceptional Lagerstätte because the coexistence of both skeletal and soft-bodied groups along a continuous record of ca. 8 million years, which is subdivided into 14 trilobite zones. Murero was the first palaeontological site in Spain to obtain the highest protection figure (Bien de Interés Cultural, BIC) from the Spanish Administration in 1997. Since then, the educational and social projection of the site is continuously increasing

Influence of plasma-generated negative oxygen ion impingement on magnetron sputtered amorphous SiO2 thin films during growth at low temperatures

Growth of amorphous SiO2 thin films deposited by reactive magnetron sputtering at low temperatures has been studied under different oxygen partial pressure conditions. Film microstructures varied from coalescent vertical column-like to homogeneous compact microstructures, possessing all similar refractive indexes. A discussion on the process responsible for the different microstructures is carried out focusing on the influence of (i) the surface shadowing mechanism, (ii) the positive ion impingement on the film, and (iii) the negative ion impingement. We conclude that only the trend followed by the latter and, in particular, the impingement of O- ions with kinetic energies between 20 and 200 eV, agrees with the resulting microstructural changes. Overall, it is also demonstrated that there are two main microstructuring regimes in the growth of amorphous SiO2 thin films by magnetron sputtering at low temperatures, controlled by the amount of O2 in the deposition reactor, which stem from the competition between surface shadowing and ion-induced adatom surface mobilityMinisterio de Innovación español-MAT 2007-65764Ministerio de Innovación español (CONSOLIDER INGENIO 2010)-CSD2008-00023Junta de Andalucía-TEP2275, TEP5283, P07-FQM-03298 y P10-FQM-690