Fundamentos de circuitos eléctricos

Este libro está dirigido a estudiantes que cursan las asignaturas de Circuitos Eléctricos y Electrotecnia. En el texto se explican distintos ejemplos y se proponen ejercicios. La primera parte del libro trata sobre las definiciones de conceptos básicos de circuitos eléctricos, la segunda parte trata sobre circuitos eléctricos en Corriente Directa y su análisis, la tercera parte habla sobre los condensadores y los inductores, finalmente, se hace un breve tratamiento de Análisis de Circuitos en Corriente Alterna (AC). Los autores esperan que este libro sea de gran ayuda a los estudiantes de ingenierías del INSTITUTO TECNOLÓGICO METROPOLITANO y de otras universidades

The Solar Twin Planet Search. V. Close-in, low-mass planet candidates and evidence of planet accretion in the solar twin HIP 68468

[Methods]. We obtained high-precision radial velocities with HARPS on the ESO 3.6 m telescope and determined precise stellar elemental abundances (~0.01 dex) using MIKE spectra on the Magellan 6.5m telescope. [Results]. Our data indicate the presence of a planet with a minimum mass of 26 Earth masses around the solar twin HIP 68468. The planet is a super-Neptune, but unlike the distant Neptune in our solar system (30 AU), HIP 68468c is close-in, with a semi-major axis of 0.66 AU, similar to that of Venus. The data also suggest the presence of a super-Earth with a minimum mass of 2.9 Earth masses at 0.03 AU; if the planet is confirmed, it will be the fifth least massive radial velocity planet discovery to date and the first super-Earth around a solar twin. Both isochrones (5.9 Gyr) and the abundance ratio [Y/Mg] (6.4 Gyr) indicate an age of about 6 billion years. The star is enhanced in refractory elements when compared to the Sun, and the refractory enrichment is even stronger after corrections for Galactic chemical evolution. We determined a NLTE Li abundance of 1.52 dex, which is four times higher than what would be expected for the age of HIP 68468. The older age is also supported by the low log(R'HK) (-5.05) and low jitter. Engulfment of a rocky planet of 6 Earth masses can explain the enhancement in both lithium and the refractory elements. [Conclusions]. The super-Neptune planet candidate is too massive for in situ formation, and therefore its current location is most likely the result of planet migration that could also have driven other planets towards its host star, enhancing thus the abundance of lithium and refractory elements in HIP 68468. The intriguing evidence of planet accretion warrants further observations to verify the existence of the planets that are indicated by our data and to better constrain the nature of the planetary system around this unique star.Comment: A&A, in pres

Graphene Materials to Remove Organic Pollutants and Heavy Metals from Water: Photocatalysis and Adsorption

Since graphene was isolated from graphite, different researches have been developed around it. The versatility of graphene properties and their derivates, such as graphene oxide or doped and functionalized graphene materials have expanded the possible applications of these nanostructures. The areas studied of graphene include the following: nanocomposites, drug delivery, transistors, quantum dots, optoelectronic, storage energy, sensors, catalyst support, supercapacitors, among others. However, other important field of these materials is their applications in environment, mainly in the removal of pollutants in water. In this context, there are two possible alternatives to use graphene materials in water purification: photocatalysis and adsorption. In the first case, the key is related to the bandgap and semiconductors properties of these materials, also the versatility of different graphene structures after the oxidation or functionalization, play an important role to get different arrangements useful in photocatalysis and avoid recombination, one of the problems of typical semiconductors photocatalysts. In the second case, surface area and useful chemical groups in carbon material give different options to produce efficient adsorbents depending on different synthesis conditions. Thus, this book chapter covers a review of the photocatalytic activity of graphene materials with emphasis in the removal of organic pollutants and heavy metals from water, in the next topics: graphene-based semiconductor photocatalyst and graphene oxide as photocatalyst. On the other hand, the chapter also discusses the research related to the removal of organic compounds and heavy metals using graphene materials as adsorbents, the topics in this second part are as follows: graphene and graphene oxide as adsorbent of heavy metals from water, graphene, and graphene oxide as adsorbent of organic pollutants from water, functionalized graphene materials as adsorbent of water pollutants, carbon nanomaterials vs. graphene as adsorbents. Therefore, the book chapter presents a review and the discussion of the keys that play an important role in the advances in the research of graphene materials as photocatalysts. In addition, the isotherms and kinetic that produce these materials as adsorbents are also reviewed and discussed, because adsorption process in these materials is important to remove pollutants from water, but also for adsorption is a first step to achieve photocatalyst. The future of this topic in graphene materials is also analyzed

MÉTODO DE PLANEACIÓN PARTICIPATIVA PARA EL DESARROLLO LOCAL EN SAN PABLO CUATRO VENADOS, ZAACHILA, OAXACA

El desarrollo local es el conjunto de procesos económicos, sociales, culturales, políticos y territoriales a través de los cuales una comunidad, a partir de sus propias potencialidades y de las oportunidades que le brinda el entorno, accede al bienestar, sin exclusiones ni discriminaciones, y garantiza las condiciones para que futuras generaciones también puedan hacerlo. Para lograrlo es necesario implementar métodos de participación ciudadana en las comunidades. Actualmente el municipio de San Pablo Cuatro Venados perteneciente al distrito de Zaachila localizado en la Región de Valles Centrales, Oaxaca, cuenta con 1,388 habitantes. En 2010, el 91% del total de la población (1403 individuos) se encontraban en pobreza, de los cuales 579 (37.6%) presentaban pobreza moderada y 824 (53.5%) estaban en pobreza extrema. El porcentaje de personas que reportó habitar en viviendas sin disponibilidad de servicios básicos fue de 97.6%, lo que significa que las condiciones de vivienda no son las adecuadas para 1504 personas. La incidencia de la carencia por acceso a la alimentación fue de 43%, es decir una población de 663 personas. (CONEVAL, 2015). Para poder subsistir las familias del municipio y núcleos rurales han desarrollado conocimientos empíricos que forman parte de los sistemas de producción que constituyen la estrategia de las familias para producir y obtener los productos básicos, para satisfacer sus necesidades principales, los sistemas de producción familiar se componen de actividades agrícolas, pecuarias, forestales, comerciales, de traspatio, de recolección y de empleo de mano de obra familiar fuera de la unidad de producción. Las cadenas productivas en éste municipio no están bien definidas, puesto que cada productor realiza un proceso diferente

An Active Learning Didactic Proposal with Human-Computer Interaction in Engineering Education: A Direct Current Motor Case Study

Engineering education requires learning strategies to engage students and improve the development of disciplinary and transversal competencies. Additionally, as economic resources are generally limited, it is sought to avoid investing large sums of money in software and hardware, as well as in fitting out laboratories. This work presents a didactic proposal within the framework of active and collaborative learning that includes the flipped classroom technique to be applied in the curriculum of undergraduate engineering programs and inside a massive flexible digital master class. The activity is the mathematical modeling, simulation, and control system of a direct current motor where simulation work is carried out in open license computational packages. Students understand the physical phenomena involved in the motor’s modeling and the input–output variables’ relations. Moreover, an analogy between an electromechanical and a pure electrical model is carried out, where the relevant variables respond in an agile and reliable manner. To validate the modeling, the differential equations are solved by applying numerical methods, and tested for control purposes. The activity has been validated with a rule-based system applied to a Likert scale survey data. This type of human–computer interaction, in the context of active learning, could engage students and motivate them to develop competencies that are highly appreciated by industry practitioners. View Full-Tex

Removal of Phenolic Compounds from Water by Adsorption and Photocatalysis

Phenolic compounds are important industrial wastes, and are classified as hazardous substances contaminating groundwater resources. Therefore, the removal or diminish of these organics compounds in order to reach the permitted levels before discharging becomes a challenging. Several processes have been developed to remove phenolic compounds from waters, including electrochemical oxidation, redox reactions, membrane separation and photocatalytic degradation. Recently, tendency of phenolic compounds removal involves adsorption and photocatalytic process, using synthetic or natural particles, such as carbon materials and clays. Actually, materials in nanometric scale play an important role in the processes previously mention due to their unique chemical and physical properties. In this book chapter, the first part shows the chemical properties of phenolic compounds that play an important role in the removal process. In the second part, different materials in macro, micro and nanosize used as adsorbents or photocatalysts are reviewed. In addition, other removal processes of phenolic compounds as electrochemistry and redox reactions are included. The removal conditions in these process, such as pH, adsorbate and adsorbent concentration are analyzed and discussed. Furthermore, special emphasis is included in micro and nanocarbon materials, used as adsorbents or photocatalyst to remove phenol from water in recently researches

Sistematización del proceso de prospectiva territorial construido en el Huila durante el periodo 1990-2010 con el soporte de la Universidad Surcolombiana

Strategic Prospective is seen as a scientific discipline which studies the future in order to diagnose it and build it from the present. Some authors call the science of hope. According to this approach, the “show strategically a territory” (constructing future scenarios) are known as Territorial prospective. There are a number of exercises for the future that have been carried out on the territory of Huila; such as the Comprehensive Plan of Neiva (PIDNE II: 1990-2015), the Huila Vision 2020, the Strategic Plan for Science, Technology and Innovation in the Huila: 2005 - 2020, the Ten-year Plan of Culture of Huila 2011-2020, among others, which have provided strategic lines for the planning of their future in 2020. In this historical context, and therefore objective methodological, the systematize the more recent prospective experiences of Huila makes it possible to identify the intentions that are common in huilense society as also the strategic route possible contained in them, toward the year 2020.La Prospectiva Estratégica es considerada como una disciplina científica que estudia el futuro con el fin de diagnosticarlo y construirlo desde el presente. Algunos autores la denominan la ciencia de la esperanza. Según este enfoque, al “visionar estratégicamente un territorio” (construyendo escenarios futuros) se le conoce como Prospectiva Territorial. Varios son los ejercicios de futuro que se han realizado en el territorio del Huila, tales como el Plan Integral de Neiva (PIDNE II: 1990-2015), la Visión Huila 2020, el Plan Estratégico de Ciencia, Tecnología e Innovación del Huila: 2005-2020, el Plan Decenal de Cultura del Huila 2011-2020, entre otros, los cuales han proporcionado líneas estratégicas para la planificación de su futuro en el 2020. En este contexto histórico, por tanto objetivo y metodológico, el sistematizar las más recientes experiencias prospectivas del Huila posibilita identificar las intencionalidades que son comunes en la sociedad huilense, como también la ruta estratégica posible contenida en ellos hacia el año 2020

Sistematización del proceso de prospectiva territorial construido en el Huila, durante el periodo 1990-2010 con el soporte de la Universidad Surcolombiana

La Prospectiva Estratégica es considerada como una disciplina científica que estudia el futuro con el fin de diagnosticarlo y construirlo desde el presente. Algunos autores la denominan la ciencia de la esperanza. Según este enfoque, el «visionar estratégicamente un territorio» (construyendo escenarios futuros) se le conoce como Prospectiva Territorial.Varios son los ejercicios de futuro que se han realizado en el Territorio del Huila; tales como el Plan Integral de Neiva (PIDNE II: 1990-2015), la VISION Huila 2020, el Plan Estratégico de Ciencia, Tecnología e Innovación del Huila: 2005-2020, el Plan Decenal de Cultura del Huila 2011-2020, entre otros, los cuales han proporcionado líneas estratégicas para la Planificación de su futuro en el 2020.En este contexto histórico, por tanto objetivo y metodológico, el sistematizar las más recientes experiencias prospectivas del Huila posibilita identificar las intencionalidades que son comunes en la sociedad huilense como también la ruta estratégica posible contenida en ellos, hacia el año 2020

Determination of HFE C282Y Mutation and its Association With the Iron Status and Viral Load in HIV Patients From Reynosa, Tamaulipas

Background: The HFE protein has a fundamental role in iron homeostasis, the HFE C282Y mutation prevents the specific function of the protein, causing greater intestinal absorption of iron and intracellular accumulation. The HIV virus causes a disease that attacks the cells of the immune system, mainly CD 4 T lymphocytes inducing their destruction and immunosuppression of the patient. Some viruses have the ability to disrupt cellular metabolic processes during their own replication, such is the case of HIV-1, which is involved in alteration of iron metabolism resulting in an overload of iron. Methods: An exploratory, descriptive, cross-sectional and prolective study was conducted, including 68 patients, ≥ 18 years old, HIV positive, attended at CAPASITS, through informed consent and application of an interview on lifestyle and health, were determined: blood pressure, anthropometric measures, CD 4 T cell count, viral load, and iron status (ferritin, iron and transferrin). Results: 41 participants were male sex (60%) and 27 (40%) of the female sex, average of 38.22 (±11.05 SD) years, with a BMI 25.30 (± 4.70 SD). The presence of the C282Y mutation was not detected, only the wild variant (100%) was identified. Patients with viral loads ≥ 40 copies/ml, were ruled out when relating viral load vs. serum ferritin (r= 0.594, r2= 0.353 and p= 0.004) with statistical significance, with a ferritin mean of 231.5 (± 216.04 SD). Conclusions: The C282Y mutation of the HFE gene is not present in the study population, due to its low frequency, so it is not related to iron overload. Because there is a high viral load, serum ferritin levels will also increase, and this may be due to the fact that HIV in addition to interfering with the Iron metabolism induces alterations in the synthesis and regulation of the secretion of this protein

Predictors of mortality among elderly dependent home care patients

The purpose of this study is to identify which variables -among those commonly available and used in the primary care setting- best predict mortality in a cohort of elderly dependent patients living at home (EDPLH) that were included in a home care program provided by Primary Care Teams (PCT). Additionally, we explored the risk of death among a sub-group of these patients that were admitted to hospital the year before they entered the home care program