Sustainable production program in the mexican mining industry: occupational risks

Speaking of mining and sustainability sounds contradictory, as the environmental impact generated by resource extraction is well known. How-ever, there are mining companies that are working to be safe and environmentally friendly. An example of this is presented in this study aimed at identifying oc-cupational risks generated by the activities of a small-scale gold and silver mine located in northwestern Mexico. The methodology followed was a Sustainable Production Program (SPP) based on a continuous cycle of five steps in which the tools of cleaner production and pollution prevention are adapted. As a result of this project, it was possible to implement SPP activ-ities: training for workers, use of personal protective equipment and adequate handling of chemicals. As a conclusion, it was verified that SPP application helped this mining company move towards sustainable pat-terns of production.Hablar de minería y sustentabilidad suena contradictorio, ya que es bien sabido el impacto ambiental que se genera por la extracción de recursos. Sin embargo, existen empresas mineras que están trabajando para ser seguras y amigables con el ambiente. Un ejemplo de lo anterior se presenta en este estudio, cuyo objetivo fue identificar los riesgos ocupacionales generados por las actividades de una pequeña mina de oro y plata ubicada en el noroeste de México. La metodología que se siguió fue un Programa de Producción Sustentable (PPS), basado en un ciclo continuo de cinco pasos, en el cual se adaptan las herramientas de producción más limpias y prevención de la contaminación. Como resultado de este proyecto, se logró implementar el PPS en actividades de: capacitación a los trabajadores, uso de equipo de protección personal y manejo de sustancias químicas. A manera de conclusión, se establece que la aplicación del PPS coadyuva a transitar hacia patrones sustentables de producción

The Eastern Filament of W50

We present new spectral (FPI and long-slit) data on the Eastern optical filament of the well known radionebula W50 associated with SS433. We find that on sub-parsec scales different emission lines are emitted by different regions with evidently different physical conditions. Kinematical properties of the ionized gas show evidence for moderately high (V ~ 100 km/s) supersonic motions. [OIII]5007 emission is found to be multi-component and differs from lower-excitation [SII]6717 line both in spatial and kinematical properties. Indirect evidence for very low characteristic densities of the gas (n ~ 0.1cm^{-3}) is found. We propose radiative (possibly incomplete) shock waves in low-density, moderately high metallicity gas as the most probable candidate for the power source of the optical filament. Apparent nitrogen over-abundance is better understood if the location of W50 in the Galaxy is taken into account.Comment: accepted to Astronomische Nachrichten; 9 pages, 4 figures, 2 table

DFT Calculations and Statistical Mechanics Applied to Isomerization of Pseudosaccharins

In the present work, molar fractions were obtained as a function of temperature with different levels of theory for the most representative isomers of three systems belonging to the family of pseudosaccharins. The choice of those three systems was due to the fact that it is known in the scientific literature that these systems present very small differences in their relative energies which make a complicated experimental characterization, in addition these compounds are of interest in the biological area. These systems represent challenges not only from an experimental point of view but also from a theoretical point of view. From the theoretical perspective, this study is also complicated since several possible isomers with very similar energies are presented. The diagrams of species distribution (molar fractions) provide information that cannot be accessed through the electronic structure calculations at T = 0. Here, this tool was useful to identify the most probable isomer from several quasi-degenerate isomers and to discern if thermal effects favor any of them, as well as to find trends despite the different results of each level of theory. Additionally, an analysis was performed on vibrational, rotational and electronic data in order to know the reason of the behavior of molar fractions as function of temperature

Murine Typhus in Child, Yucatan, Mexico

A case of murine typhus in Yucatan was diagnosed in a child with nonspecific signs and symptoms. The finding of Rickettsia typhi increases the number of Rickettsia species identified in Yucatan and shows that studies are needed to determine the prevalence and incidence of rickettsioses in Mexico

Segregación residencial en las zonas metropolitanas del estado de Hidalgo

La segregación residencial en las zonas metropolitanas del estado de Hidalgo: Tulancingo, Tula y Pachuca interesa ser estudiada para conocer la estructura urbana que impacta las zonas residenciales de las tres principales áreas urbanas del estado de Hidalgo. El presente trabajo forma parte de los avances de investigación del estudio sobre los patrones de segregación en estas tres áreas metropolitanas durante el periodo de 2010 a 2020. Hay una serie de investigaciones relacionadas a la segregación socioespacial en distintas ciudades latinoamericanas (incluyendo las mexicanas), que explican este proceso; no obstante, en el estado de Hidalgo no se ha elaborado un análisis detallado que dé cuenta de este fenómeno. Se realiza una revisión teórica sobre la segregación residencial, posteriormente se muestra un panorama general de las tres Zonas Metropolitanas del Estado de Hidalgo y por último se muestra el estudio a detalle de la zona que ha presentado un crecimiento de población significativo, la Zona Metropolitana de Tula, se analizan las siguientes dimensiones: perfil sociodemográfico de la población, distribución de las viviendas, perfil económico de la población, arreglos residenciales, así como condiciones de la vivienda, durante el año 2010

Reactivity Indexes and Structure of Fullerenes

The discovery of fullerenes and their production in measurable quantities launched many studies about their reactivity and possible applications. Their peculiar structure opened possibilities for their study, initially replacing carbon atoms with alternative atoms. The surface also offers the possibility of attaching several species and the interior of their hollow structure represents a challenge because of the possibility of confining elements or molecules that may become less stable when attached to the exterior of the cage. These modifications may considerably affect both chemical and physical properties. In this chapter, we propose the encapsulation of 3–10 nitrogen atoms as aggregates inside the C70 cage. We also study the structures and reactivity indexes and the stabilization conferred as a result of being part of the fullerene. These aggregates are mainly of interest because of their possible application as energetic materials

Study of a hybrid solar absorption-cooling and flash-desalination system

Producción CientíficaIn this work, the analysis of a hybrid LiBr/H2O absorption-cooling and flash-desalination system, using solar thermal energy as heat source, is presented. An absorption open-cycle with three pressure levels is used in combination with a single-stage flash-desalination process to use the coolant as product water, resulting in an increase in cooling and desalination efficiency. For the application, a 20-room coastal hotel complex in San Felipe, Baja California, Mexico, is taken as a case study and the sizing of the solar collection and storage system is carried out for the operation of the proposed hybrid system, during the summer operative period. The operational dynamics during the week with the highest ambient temperatures are presented. The dimensioning of the solar collector’s area and the energy storage resulted in a collection area of 620 m2 with 30 m3, respectively, reaching a solar fraction of 69%. The absorption-cooling subprocess showed an increase of 13.88% in the average coefficient of performance (COP) compared to conventional LiBr/H2O absorption systems. Also, considering that the system provides cooling and desalination simultaneously, the average COPG is 1.64, which is 2.27 times higher than the COP of conventional LiBr/H2O single-effect absorption units. During the critical week, the system presented a desalinated water production of 16.94 m3 with an average performance ratio (PR) of 0.83, while the average daily water production was 2406 kg/day; enough to satisfy the daily water requirements of four people in a coastal hotel in Mexico or to cover the basic services of 24 people according to the World Health Organization

Simulation of a solar-assisted air-conditioning system applied to a remote school

Producción CientíficaIn this work, we present an absorption cooling system with 35 kW capacity driven by solar thermal energy, installed in the school of Puertecitos, Mexico, an off-grid community with a high level of social marginalization. The cooling system provides thermal comfort to the school’s classrooms through four 8.75-kW cooling coils, while a 110-m2 field of evacuated tube solar collectors delivers the thermal energy needed to activate the cooling machine. The characteristics of the equipment installed in the school were used for simulation and operative analysis of the system under the influence of typical factors of an isolated coastal community, such as the influence of climate, thermal load, and water consumption in the cooling tower, among others. The aim of this simulation study was to determine the best operating conditions prior to system start-up, to establish the requirements for external heating and cooling services, and to quantify the freshwater requirements for the proper functioning of the system. The results show that, with the simulated strategies implemented, with a maximum load operation, the system can maintain thermal comfort in the classrooms for five days of classes. This is feasible as long as weekends are dedicated to raising the water temperature in the thermal storage tank. As the total capacity of the system is distributed in the four cooling coils, it is possible to control the cooling demand in order to extend the operation periods. Utilizing 75% or less of the cooling capacity, the system can operate continuously, taking advantage of stored energy. The cooling tower requires about 750 kg of water per day, which becomes critical given the scarcity of this resource in the community.CONACYT-SENER-SUSTENTABILIDAD ENERGÉTICA (project P09)Programa Iberoamericano de Ciencia y Tecnología para el Desarrollo (project 518RT0558

El impacto de la vivienda deshabitada en la segregación socio espacial de la Zona Metropolitana de Pachuca

La segregación ha sido abordada desde diferentes dimensiones, resulta de interés prioritario para la consolidación de un marco crítico hacia la planeación eficiente de los entornos urbanos, el comprender aquellas características que impactan desde el fenómeno espacial toda dimensión de la estructura social de la población. Para la presente exposición de resultados de investigación, y como parte estructural de la etapa inicial del proyecto División social del espacio en regiones centro y norte de México, se toma como eje de análisis la segregación socio espacial con relación al crecimiento acelerado de la vivienda deshabitada en la Zona Metropolitana de Pachuca en las últimas décadas, ¿Cómo la vivienda deshabitada ha contribuido en elevar la desintegración social dentro de los mismos conjuntos habitacionales? Se explora el marco referencial como parte del proceso de identificación del modelo dimensional que incide directamente en la segregación a partir de características físicas y el desuso o deshabitación de la vivienda bajo el esquema de desarrollo de interés social y sus repercusiones en patrones de organización socio espacial de la población. Se presentan como referente principal de este trabajo tres condiciones que habrán de consolidar la identidad causal del fenómeno de deshabitación de la vivienda y los efectos en la organización de la población en el territorio; la definición derivada de la exploración de datos de carácter cuantitativo con respecto al número de viviendas deshabitadas y su entorno demográfico, el marco normativo que estimula la oferta de este tipo de viviendas y la definición física del concepto de vivienda habitable por su posible relación con el abandono o no habitación de la vivienda