Acta Universitaria

5-13

Authors: Jose de Jesus Rodríguez Ibarra, Juan T. Frías Hernández, Víctor Hugo Rangel Hernández

The tanning industry is a source of contamination by hazardous waste generation and special handling. One of these elements is the flesh, which help this study to determine if fleshing is able to add value to a source of employment and a reduction of pollution: production of biodiesel promises to be the sustainable alternative, economically and socially viable. The study was divided into 3 unit processes with a base of 1 kg of biodiesel: a) flesh collection, b) cooked and rendered, c) esterification and transesterification. The impact categories evaluated were the primary energy consumption and the potential nonrenewable emissions of greenhouse gases. As a result of this article, it is had that the tanning is a source of biodiesel economically and environmentally feasible for the least environmental impact occurred. With the availability of annual flesh (79 200 000 kg) can be reduced combustion emissions of CO2 from the air to 11 980 300 kg per year.

25-31

Authors: Maximino Tapia Rodriguez, Salvador Botello, Luz Angélica Caudillo, Héctor Hernández, Iván Munguía, Jacob Esaú Salazar, Ernesto Ortega, Juan Carlos Gómez, Daniel Quiroz, Miguel Yáñez

Se presenta un laboratorio virtual que realiza el análisis, diseño y optimización de estructuras de acero rolado en frío, así como la cuantificación de los materiales utilizados en la construcción de la techumbre completa y el costo de fabricación e instalación la misma. El software está dotado con una interfaz de usuario amigable desarrollado para la empresa “Tejas El Águila”. El análisis estructural considera cargas de peso propio, muertas y vivas, a las que estará sometida la estructura en condiciones de servicio, además de considerarse los efectos de viento y sismo para la República Mexicana -de acuerdo a la normatividad vigente. El optimizador está basado en métodos de minimización de entropía con restricciones múltiples, evaluando cada una de las estructuras por el método de la rigidez. Para la evaluación de la eficiencia de la estructura, se utiliza la normativa American Iron and Steel Institute- Allowable Stress Design (AISI-ASD). La optimización de las estructuras se realiza haciendo múltiples evaluaciones de diferentes configuraciones de las mismas, tarea que se ha paralelizado utilizando técnicas de programación de memoria compartidaOpen Multiprocessing (OpenMP). La combinación adecuada del seguimiento de las normatividades vigentes, la implementación del optimizador y los métodos matriciales para el cálculo de estructuras, aunado al ambiente grafico fácil de usar y amigable, han resultado en un potente software que genera soluciones de vivienda económicas, seguras y estéticas (favoreciendo así a un amplio sector de la sociedad mexicana).

37-46

Authors: Eduardo Fernández Guzmán

This paper proposes a novel view of theoretical and historiographical approaches, as a first attempt, discussing the multicausal nature of contemporary international migration Mexico- United States. The intention is not going deeper into the different causal mechanisms, but only list them and ponder their interaction to better understand this phenomenon that goes beyond the macro-level considerations (economic and political). Migration, understood as a social process, manifests various causes and consequences in their past and present. And, in the case of the mass migration of Mexicans to the United States in recent decades, it is givable to think that this is a product of historical trends, economic asymmetries, of deep social inequalities and poverty in Mexico, of push and the pull factors, tradition and socialization migrant, social networks, transnational communities, symbolisms and collective imaginaries, modernization in transport and communication, migration industry, cultural values and psychological components, among others. It proposal is to analyze briefly this binational contemporary phenomenon under the epistemological consideration that migration is a social process. For this, macro, meso and microstructures will be essential in the explanation.