Cálculo del caudal ambiental mediante una metodología holística en la cuenca alta del río Bogotá

Saneamiento de comunidadesEl presente proyecto, mediante un caso de estudio, se aplica la metodología de Caudal Ambiental propuesto por la ANLA en la cuenca alta del río Bogotá y se compara con algunas metodologías adicionales utilizadas para el cálculo del caudal ambiental.INTRODUCCIÓN 1. GENERALIDADES DEL TRABAJO DE GRADO 2. MARCO DE REFERENCIA 3. METODOLOGÍA 4. ANÁLISIS DE RESULTADOS 5. CONCLUSIONES Y RECOMENDANCIONES BIBLIOGRAFÍAEspecializaciónEspecialista en Recursos Hídrico

Diseño de un plan de mantenimiento preventivo para aumentar la fiabilidad operacional y reducción de costos de mantenimiento de los equipos en la Empresa San Francisco de Asís Logística y Negocios S.A.C

La presente tesis tiene como propósito diseñar un plan de mantenimiento preventivo que permita aumentar la fiabilidad operacional de los equipos de la empresa San Francisco de Asís Logística & Negocios SAC y contribuya en la reducción de costos de mantenimiento. La primera parte de esta investigación se basó en recaudar la mayor información acerca de los equipos: datos técnicos, historial de fallas, servicios realizados a cada equipo, etc. También se determinó los gastos que realizo la empresa en el periodo noviembre 2014 – julio 2015 por concepto de reparaciones y averías de emergencia (mantenimiento correctivo) Luego con los datos obtenidos se procedió al cálculo de indicadores de mantenimiento, así como también se procedió a determinar el análisis de criticidad para cada equipo. Los resultados mostraron un aumento de disponibilidad de los equipos de 3.9%, así como también un aumento de criterio de confiabilidad de 6.35% poniendo en práctica el plan de mantenimiento. Respecto al nivel de criticidad de los equipos solo uno tiene un nivel alto, para lo cual se tomaron las consideraciones necesarias. Para el diseño del plan de mantenimiento se tomaron algunas especificaciones técnicas de cada equipo de modo que se garantice una mayor vida útil para los componentes de cada equipo. Respecto a las hojas de control y supervisión se elaboraron tomando en cuenta el rol que cumplen cada una de ellas, tratando de generar la cantidad de datos útiles y necesarios para un buen historial de falla y reporte de costo

Caracterización mecánica de espumas cerámicas de zirconio y carburo de Silicio

En este trabajo fue estudiado el comportamiento mecánico a compresión de filtros porosos de Zirconio y Carburo de Silicio. Se estudió la aplicabilidad de un modelo estadístico de Weibull a las celdas unitarias que conforman todo el material, empleándolos para analizar el esfuerzo a compresión que soportan. Se ha comprobado que este modelo, reproduce adecuadamente los valores para los cuales el material falla a estos esfuerzos ya que poseen una distribución estrictamente aleatoria. Además, se pudo observar a través de un análisis morfológico por medio de microscopia óptica y electrónica de barrido las características principales del material, teniendo en cuenta los huecos triangulares que conforman las paredes de cada una de las celdas unitarias y se propone en base a su morfología un modelo teórico en el cual es posible predecir el esfuerzo a compresión de una celda unitaria. Para finalizar, se propone para mejorar la resistencia de estos materiales, introducir una capa de metal antes del proceso de sinterización. Este análisis se ve reflejado igualmente en el modelo teórico planteado.Abstract: In this work the mechanical behavior to compression of porous filters of Zirconium and Silicon Carbide was studied. The maximum stresses that these fragile ceramic materials can withstand have traditionally been studied by statistical methods, most notably the Weibull Model. It was studied the applicability of this model to the unit cells that make up the whole material, using them to analyze the maximum compression effort they support. It has been shown that the Weibull statistical model adequately reproduces the values for which the material fails these efforts as they have a strictly random distribution. In addition, the main characteristics of the material could be observed through a morphological analysis using optical microscopy and scanning electron microscopy, considering the triangular holes that make up the walls of each of the unit cells, and it is proposed based on Its morphology a theoretical model in which it is possible to predict the compressive stress of a unit cell. Finally, it is proposed to improve the strength of these materials, introduce a layer of metal before the sintering process. This analysis is also reflected in the theoretical model proposed.Maestrí

Identity and Oppression: Differential Responses to an In-Between Status

Oppression operates at various levels, with varying degrees of negativity, and groups respond in markedly different ways. In this paper, the in-between status of the colored South African group is used to illustrate issues of identity and oppression under the Apartheid system—and differing ways in which oppression was experienced and used. The colored group had many social advantages over Blacks, but were also used to oppress that group. Habituation, accommodation, and relative advantage were identified as dynamics within the broader context of power and privilege that contributed to cultural and psychological marginality and status ambivalence of the coloreds. These processes must be understood within the historical, social, and political context of the community. What is evident from the data is that groups and individuals can take up various positions along a continuum of oppressor—oppressed, depending upon the contexts, time, and social and legal relationships involved in their interactions

Evaluation of hydrochars from lignin hydrous pyrolysis to produce biocokes after carbonization

Hydrochars were obtained after hydrous pyrolysis of a pine Kraft lignin using different reaction conditions (temperature, water content and residence time) and the residues were characterized through a wide range of analytical techniques including high-temperature rheometry, solid-state 13C nuclear magnetic resonance (NMR), thermal gravimetric analysis (TGA), diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) and field emission scanning electron microscopy (FE-SEM). The results indicated that an increase in reaction temperature, an increase in residence time or a decrease in water content reduces the amount of fluid material in the residue. The hydrous pyrolysis conditions studied were not able to increase the maturation of lignin, which would result in an increase in the resolidification temperature, but reduced the amount of mineral matter in the hydrochar produced. On the other hand, the hydrochars obtained from pristine lignin, torrefied lignin (300 °C, 1 h) and their 50:50 wt.%/wt.% blend at temperatures of 350 °C after 6 h using 30 ml of water had lower ash contents (45%) is excessively high compared to that of the good coking coal (10%) and the micro-strength of the biocokes (R139%) and high microporous surface areas ( > 400 m2/g) of the biocokes and high alkalinity index of the lignins (>27%) compared to those of the coke (27% and 145 m2/g) and coal (0.6%), respectively. Furthermore, the biocoke derived from the hydrous pyrolysed torrefied lignin did not agglomerate, which could not be explained by changes in the chemical properties of the material and requires further investigation

Evidence for a physically bound third component in HD 150136

Context. HD150136 is one of the nearest systems harbouring an O3 star. Although this system was for a long time considered as binary, more recent investigations have suggested the possible existence of a third component. Aims. We present a detailed analysis of HD 150136 to confirm the triple nature of this system. In addition, we investigate the physical properties of the individual components of this system. Methods. We analysed high-resolution, high signal-to-noise data collected through multi-epoch runs spread over ten years. We applied a disentangling program to refine the radial velocities and to obtain the individual spectra of each star. With the radial velocities, we computed the orbital solution of the inner system, and we describe the main properties of the orbit of the outer star such as the preliminary mass ratio, the eccentricity, and the orbital-period range. With the individual spectra, we determined the stellar parameters of each star by means of the CMFGEN atmosphere code. Results. We offer clear evidence that HD 150136 is a triple system composed of an O3V((f\ast))-3.5V((f+)), an O5.5-6V((f)), and an O6.5-7V((f)) star. The three stars are between 0-3 Myr old. We derive dynamical masses of about 64, 40, and 35 Msun for the primary, the secondary and the third components by assuming an inclination of 49{\deg}. It currently corresponds to one of the most massive systems in our galaxy. The third star moves with a period in the range of 2950 to 5500 d on an outer orbit with an eccentricity of at least 0.3. This discovery makes HD 150136 the first confirmed triple system with an O3 primary star. However, because of the long orbital period, our dataset is not sufficient to constrain the orbital solution of the tertiary component with high accuracy.Comment: 13 pages, 11 figures, accepted at A&

Rocketing restoration : enabling the upscaling of ecological restoration in the Anthropocene

In the 25 years during which the Society for Ecological Restoration (SER) has overseen the publication of Restoration Ecology, the field has witnessed conceptual and practical advances. These have become necessary due to the scale of environmental change wrought by the increasing global human population, and associated demands for food, fiber, energy, and water. As we look to the future, and attempt to fulfill global restoration commitments and meet sustainable development goals, there is a need to reverse land degradation and biodiversity loss through upscaling ecological restoration. Here, we argue that this upscaling requires an expanded vision for restoration that explicitly accounts for people and nature. This expansion can assess success in a future-focused way and as improvements relative to a degraded socio-ecological system. We suggest that upscaling requires addressing governance, legal and ethical challenges, investing in technological and educational capacity building, bolstering the practical science necessary for restoration, encouraging adoptable packages to ensure livelihoods of local stakeholders, and promoting investment opportunities for local actors and industry. Providing SER embraces this socio-ecological vision, it is ideally placed to aid the achievement of goals and remain globally relevant. SER needs to harness and coordinate three sources of potential energy (global political commitments, the green economy, and local community engagement) to rocket restoration into the Anthropocene. With principles that can embrace flexibility and context-dependency in minimum restoration standards, SER has the potential to guide socio-ecological restoration and help realize the ultimate goal of a sustainable Earth

IDENTIFICACIÓN DE GENES DE SOBREEXPRESIÓN DURANTE EL PROCESO DE EMBRIOGÉNESIS SOMÁTICA EN Agave angustifolia HAW

El género Agave es nativo del Continente Americano y muestra su mayor diversidad en México; desde la antigüedad, muchas especies de este género se han utilizado en México para la producción de alimentos, fibras, azúcares, jarabes, celulosa, ensilado para el ganado, productos farmacéuticos, obtención de sapogeninas, como plantas ornamentales, elaboración de bebidas alcohólicas y muchos otros productos (Portillo et al., 2007); una de estas especies es A. angustifolia, la cual se utiliza para la producción de mezcal. A. angustifolia puede ser multiplicado vegetativamente ya sea a través de bulbillos o estolones (hijuelos), sin embargo, la tasa de adaptación a condiciones de campo es muy baja. Además, en condiciones ambientales óptimas el agave florece sólo una vez en su vida (8-30 años de edad) pero rara vez se obtienen semillas viables (Tejavathi et al., 2007). Por otro lado, el incremento en la producción de mezcal ha ocasionado la sobreexplotación de dicha especie (Nikam et al., 2003). Igualmente, la recolección de plantas y semillas, así como la destrucción de su entorno natural han reducido significativamente las poblaciones de este agave en su hábitat nativo. Por lo anterior, la urgente necesidad de obtener un gran número de individuos uniformes de genotipos elite, ha llevado al desarrollo de técnicas de cultivo in vitro para propagar masivamente varias especies del género Agave, en este sentido, recientemente se ha reportado un procedimiento para la regeneración de plantas vía embriogénesis somática de A. angustifolia (Arzate-Fernández and Mejía-Franco, 2011)

Ocupación espectral de la banda ISM de 2.4 GHz para aplicaciones de radio cognoscitivo

La tecnología de radio cognoscitivo representa una prometedora solución al problema de escasez de espectro electromagnético, dado que una gran parte del espectro asignado se utiliza de forma esporádica, existiendo una subutilización del mismo. En la banda industrial, científica y médica (ISM, por sus siglas en inglés) de 2.4 GHz, varias campañas de mediciones se han realizado para determinar la ocupación real del espectro. En este trabajo se describe una metodología para obtener la ocupación espectral de la banda ISM de 2.4 GHz, en las instalaciones de la Facultad de Ciencias en la Universidad Autónoma de San Luis Potosí. Se presentan los resultados de la densidad espectral de potencia y el ciclo de trabajo. Estos resultados indican claramente que la utilización del espectro es baja, a pesar de que muchas tecnologías de comunicación inalámbrica comparten este recurso.Palabras Claves: banda ISM, ciclo de trabajo, ocupación espectral, radio cognoscitivo

Understanding the unusual fluidity characteristics of high ash Indian bituminous coals

High-temperature rheometry and 1H nuclear magnetic resonance (NMR) are two complementary techniques that have been used to investigate fluidity development quantitatively in the 105 Pa.s), the maximum concentration of fluid H was quite similar to that of the good coking coal (40%). This Indian non-coking coal developed fluid H with the greatest mobility (T2L > 150 μs) in the coal series, regardless of the particle size fraction studied. The probable explanation for this abnormal behavior is that the mineral matter prevents bulk movement in the sample but the local mobility of the fluid phase is still high on the nanometer scale. Blending the two Indian non-coking coals with the highly fluid medium coking coal gave higher viscosities (i.e. lower fluidity) than predicted by the polymer blend rule, probably again due to the high mineral matter restricting bulk flow. This negative effect was less pronounced with the higher ash coal suggesting that the high mobility of the fluid entities in this coal might prevent the destruction of fluid entities evolving from the medium coking coal. Partial demineralization of the high ash Indian non-coking coal to 17 wt% through a sink-float method did not decrease the complex viscosity of this coal but reduced the maximum mobility of the fluid H to levels observed with the lower ash content (20 wt%) Indian coal. Therefore, this reduction in mobility could be directly related to the mineral matter in the Indian non-coking coal