Design and manufacturing of master alloys for sintering activation in high performance structural parts

Nowadays, the development of high performance structural parts, is limited by the fact that the alloying systems are being modifying by requirements associated to envorimental guideline as well as to the increase in the price of raw materials. The use of masteralloys allows to activate the mass transport processes during sintering with a minimum modification of final composition (low cost) acting on densification, and hence, on final properties. The research group of “Powder Technology” from Carlos III University, has a wide experience and qualification on the design of new alloying systems and in manufacturing the powders by atomization and mechanical alloying techniques. The Group is looking for companies interested in technical cooperation or manufacturing agreement

Labor supply of married women in Mexico: 1990-2000

In the last couple of decades, and in particular during the last couple of administrations, the Mexican government has implemented various social programs targeted specifically to women, such as PROGRESA/Oportunidades, a child care program, and a gender equality program (PROIGUALDAD). The impact that those programs may have on the work behavior of women largely depends on the form that the female labor supply takes, and in particular, on the labor supply elasticities with respect to own wages, and the husband’s wages. Despite this fact, the literature on female labor supply in Mexico is very scarce. To our knowledge, there is no estimate of the female labor supply elasticities at the national level. This paper fills in this gap in the literature. Using data from the 1990 and 2000 Mexican Census of Population, we estimate a structural model of labor supply through an application of Wooldridge’s (2002) threestep procedure. We …nd that the female labor supply elasticities had a rather sharp decrease between 1990 and 2000, which suggests that women are getting increasingly attached to the labor market. We also find evidence of heterogenous effects for women with young children and women of different cohorts. Even though female are now less responsive to changes in wages, the elasticities that we …nd are still large enough so that social programs aimed at modifying females´ work behavior through incentives might still be very successful.wage inequality, Mexico, labor supply, employment, married women

Customer-oriented risk assessment in Network Utilities

For companies that distribute services such as telecommunications, water, energy, gas, etc., quality perceived by the customers has a strong impact on the fulfillment of financial goals, positively increasing the demand and negatively increasing the risk of customer churn (loss of customers). Failures by these companies may cause customer affection in a massive way, augmenting the intention to leave the company. Therefore, maintenance performance and specifically service reliability has a strong influence on financial goals. This paper proposes a methodology to evaluate the contribution of the maintenance department in economic terms, based on service unreliability by network failures. The developed methodology aims to provide an analysis of failures to facilitate decision making about maintenance (preventive/predictive and corrective) costs versus negative impacts in end-customer invoicing based on the probability of losing customers. Survival analysis of recurrent failures with the General Renewal Process distribution is used for this novel purpose with the intention to be applied as a standard procedure to calculate the expected maintenance financial impact, for a given period of time. Also, geographical areas of coverage are distinguished, enabling the comparison of different technical or management alternatives. Two case studies in a telecommunications services company are presented in order to illustrate the applicability of the methodology

Large Scale Morphological Segregation in Optically Selected Galaxy Redshift Catalogs

We present the results of an exhaustive analysis of the morphological segregation of galaxies in the CfA and SSRS catalogs through the scaling formalism. Morphological segregation between ellipticals and spirals has been detected at scales up to 15-20 h$^{-1}$ Mpc in the CfA catalog, and up to 20-30 h$^{-1}$ Mpc in the SSRS catalog. Moreover, it is present not only in the densest areas of the galaxy distribution, but also in zones of moderate density.Comment: 9 pages, (1 figure included), uuencode compressed Postscript, (accepted for publication in ApJ Letters), FTUAM-93-2

A new strategy to design SIW-fed arrays

In this work, a new full-wave strategy, with very low iteration times, is proposed for the optimization and design of antenna arrays fed by substrate integrated waveguides. The device is decomposed into fixed and modifiable (to be optimized) sections, whose generalized scattering matrices are precomputed. The response of the array is calculated by considering firstly only the interactions between the fixed sections, which are then coupled to the modifiable ones in each iteration of an optimization process. To validate the proposed strategy, a transversal 16-slot antenna array, placed on the top plate of a substrate integrated waveguide, has been designed. A speed-up factor of over 2000 times, compared to general purpose commercial software, has been obtained in this optimization process. The final design presents a 1.05 GHz bandwidth under - 10 dB in terms of |S11|, a maximum realized gain of 17.5 dBi at 17 GHz, and a 99.95% maximum efficiency (without dielectric and conductor losses). Index Terms—Addition theorems, cylindrical modes, spherical modes, optimization process, antenna array, substrate integrated waveguide (SIW)

Los inicios de la economía de producción en el estuario Tinto-Odiel : el asentamiento prehistórico de Casa del Río (Aljaraque, Huelva)

La investigación arqueológica sobre el proceso de génesis y consolidación de estrategias productoras en el marco global del suroeste penínsular y en los contextos fluviomarítimos de la provincia de Huelva, en particular, apenas cuenta, hoy por hoy con resultados contrastados que puedan contribuir a esclarecer la cuestión. La excavación en el asentamiento de Casa del Río (Aljaraque, Huelva) ha aportado bases tanto para el análisis y definición del proceso histórico de aquellos grupos, su organización social, economía, etc., cuanto para el planteamiento de un modelo hipotético zonal del tránsito de sociedades cazadoras-recolectoras a productoras._______________________Nowadays, the archaeological research on the process of genesis and consolidation of producing strategies in the Southwest of the Iberian Peninsula, specially, on the fluvial and maritime context of the province of Huelva, hardly posseses contrasting results that clarify the isue. Anyway, thexcavations in the settlement of "Casa del Río" (Aljaraque, Huelva) have provided foundations for both the analysis and definition of the historical process, social organisation, economy, etc, for these groups. Besides, they have introduced a hypothetical model that enables the shift from hunting-farming societies to producing ones

Consejo de Estado : facultad de control de constitucionalidad

272 páginas incluye ilustraciones y diagramasQueremos agradecer a la Universidad de La Sabana por su formación, no solamente académica, sino también por los valores que nos inculcó a lo largo de nuestra carrera, que nos llevó a ser personas de bien, y que guiadas por la mano de Dios, podremos llegar a desarrollar trabajos de la importancia y calidad, como el presente, el cual desarrolla el tema de la competencia que le fue atribuida por la Carta Política de 1991, en su artículo 237 2, al Consejo de estado, Máximo Organo de la Jurisdicción Contenciosa Administrativa, para conocer de la acción de nulidad por inconstitucionalidad que se interponga contra los decretos expedidos por el Gobierno Nacional, cuya competencia no hay sido atribuida a la Corte Constituciona

Toward high performance in powder metallurgy

Powder Metallurgy (PM) is technology well known for mass production of parts at low cost but usually with worse mechanical properties than same parts obtained by alternative routes. But using this technology, high performance materials can be obtained, depending of the processing route and the type and amount of porosity. In this paper, a brief review of the capabilities of powder technology is made with the objective of attaining the highest level of mechanical and physical properties. For this purpose, different strategies over the processing can be chosen: to act over the density/porosity level and properties of the pores, to act over strengthening mechanisms apart from the density of the material (the alloying system, the microstructure, the grain size,..), to improve the sintering activity by different routes and to use techniques that avoid the grain growth during sintering

The effect of teaching methodological strategies on the development of the speaking skill in the students of eleventh grade at the "Augusto C. Sandino" high school in Niquinohomo during the second semester, 2014

Speaking is the most useful skill to develop communication with many people around the world or with foreigners making use of the language naturally to provide good interaction of ideas with others. At present, students are developing few speaking skills and they are being affected in the process of the English language learning which do not allow them to carry out a good conversation. The problematic on how to apply teaching strategies to develop the speaking skill, should be considered immediately and find out a solution to the students to increase a good level of the communication skill in English. The development of this research allows to apply the knowledge gained in the field of research methodology, experienced each of the processes in which was divided the methodology used, and thus student help to suggest the teacher how to implement teaching strategies properly to the students to reach the appropriate level of the speaking skill management. This research project takes into consideration the variables that support and determine “The effect of teaching methodological strategies on the development of speaking skill in students of eleventh grade” at Augusto C Sandino in Niquinohomo. Moreover, this research provides information in different methods and strategies to improve the speaking skill in the classroom. Furthermore, to analyze the problematic and find out a suitable solution of this, it was necessary to make use of some instruments such as: student’s survey, teacher’s interview and class observation

Las instituciones científico-medicas en la Murcia del XVIII : un intento fracasado de renovación de la formación médica

Presentamos un estudio sobre dos intentos que, en la Murcia del siglo XVIII, pretendieron mejorar y actualizar la formación que recibían los profesionales sanitarios. Ambos fracasaron, aparentemente por falta de acuerdo entre sus promotores, si bien pensamos que las causas fueron más profundas y habría que buscarlas en la escasa actividad científica que se desarrolló en la ciudad, lo que hacía innecesaria la existencia de instituciones docentes o de otras como las Academias de Medicina