Células de combustible y su uso como sistemas de propulsión

En el presente trabajo fin de grado se ha llevado a cabo un estudio y análisis de los diferentes tipos de celdas de combustible, desde su origen, su desarrollo a lo largo del tiempo, hasta los diferentes tipos que hay en la actualidad, así como las partes más representativas que las constituyen. Tras evaluar las distintas opciones, se ha llegado a la conclusión que las celdas de combustible tipo PEM son las que se encuentran en un estado más avanzado de desarrollo e implantación. Con esto, se ha optado por centrar el trabajo en este tipo de sistemas, describiendo con más detalle los componentes de los que está formado, y su funcionamiento. Para ello se ha realizado el diseño orientado a la fabricación de un pequeño prototipo que muestre su trabajo. Se han analizado los distintos pros y contras de esta tecnología para comprobar su viabilidad como alternativa a los sistemas de generación de energía, y más concretamente a los sistemas de propulsión en diferentes vehículos. Teniendo en cuenta que el hidrógeno es el principal combustible de estos sistemas, se ha realizado un estudio del mismo, analizando las distintas formas para su obtención, llegando a la conclusión que a día de hoy debe ser obtenido a partir de combustibles fósiles, ya que métodos como la electrolisis del agua todavía no se encuentran bien desarrollados para este fin. Del mismo modo, se han clasificado los diferentes métodos de almacenamiento de este combustible

Electromethanogenesis for the conversion of hydrothermal carbonization exhaust gases into methane

[EN] Hydrothermal carbonization (HTC) is a biomass conversion process that generates a CO2-rich gaseous phase that is commonly released directly into the atmosphere. Microbial electromethanogeneis (EM) can potentially use this off-gas to convert the residual CO2 into CH4, thus avoiding GHG emissions while adding extra value to the overall bioprocess. In the present work, the HTC gas phase was fed to two mixed-culture biocathodes (replicates) polarized at −1.0V vs. Ag/AgCl. Compared to pure CO2, HTC gas had a marked negative effect on the process, decreasing current density by 61%, while maximum CH₄ yield contracted up to 50%. HTC also had an unequal impact on the cathodic microbial communities, with the methanogenic hydrogenotrophic archaea Methanobacteriaceae experiencing the largest decline. Despite that, the present study demonstrates that HTC can be used in EM as a raw material to produce a biogas with a methane content of up to 70%.S

Biochar and Energy Production: Valorizing Swine Manure through Coupling Co-Digestion and Pyrolysis

[EN] naerobic digestion is an established technological option for the treatment of agricultural residues and livestock wastes beneficially producing renewable energy and digestate as biofertilizer. This technology also has significant potential for becoming an essential component of biorefineries for valorizing lignocellulosic biomass due to its great versatility in assimilating a wide spectrum of carbonaceous materials. The integration of anaerobic digestion and pyrolysis of its digestates for enhanced waste treatment was studied. A theoretical analysis was performed for three scenarios based on the thermal needs of the process: The treatment of swine manure (scenario 1), co-digestion with crop wastes (scenario 2), and addition of residual glycerine (scenario 3). The selected plant design basis was to produce biochar and electricity via combined heat and power units. For electricity production, the best performing scenario was scenario 3 (producing three times more electricity than scenario 1), with scenario 2 resulting in the highest production of biochar (double the biochar production and 1.7 times more electricity than scenario 1), but being highly penalized by the great thermal demand associated with digestate dewatering. Sensitivity analysis was performed using a central composite design, predominantly to evaluate the bio-oil yield and its high heating value, as well as digestate dewatering. Results demonstrated the effect of these parameters on electricity production and on the global thermal demand of the plant. The main significant factor was the solid content attained in the dewatering process, which excessively penalized the global process for values lower than 25% TS.SIThis research was funded by FGULEM, grant number NT55-2018. Judith González would like to thank the Junta de Castilla y León (Consejería de Educación) fellowship, Orden EDU/1100/2017, co-financed by the European Social Fund

Hydrothermal carbonization of olive tree pruning as a sustainableway for improving biomass energy potential: effect of reaction parameters on fuel properties

Hydrothermal carbonization (HTC) allows the conversion of organic waste into a solid product called hydrochar with improved fuel properties. Olive tree pruning biomass (OTP), a very abundant residue in Mediterranean countries, was treated by HTC to obtain a solid fuel similar to coal that could be used in co-combustion processes. Three different reaction temperatures (220, 250, and 280 °C) and reaction times (3, 6, and 9 h) were selected. The hydrochars obtained were extensively analyzed to study their behavior as fuel (i.e., ultimate, proximate, fiber and thermogravimetric analysis, Fourier-transform infrared spectroscopy (FTIR), activation energy, and combustion performance). The concentrations of cellulose, hemicellulose, and lignin in the samples depict a clear and consistent trend with the chemical reactions carried out in this treatment. Regarding O/C and H/C ratios and HHV, the hydrochars generated at more severe conditions are similar to lignite coal, reaching values of HHV up to 29.6 MJ kg-1. The higher stability of the solid is reflected by the increase of the activation energy (≈60 kJ mol-1), and ignition temperatures close to 400 °C. With this, HTC is a proper thermal treatment for the management of raw OTP biomass and its further conversion into a solid biofuel.Judith González-Arias would like to thank the Junta de Castilla y León (Consejería de Educación) fellowship, Orden EDU/1100/2017, cofinanced by the European Social Fund.info:eu-repo/semantics/publishedVersio

Evaluation of Joint Management of Pine Wood Waste and Residual Microalgae for Agricultural Application

[EN] This work addresses the joint management of residual microalgae and pine wood waste through pyrolysis to obtain a solid product for its use as soil amendment and two other by-products (liquid and gaseous) that can be used for energy purposes. Two management routes have been followed. The first route is through the co-pyrolysis of mixtures of both residual materials in several proportions and the later use of their solid fraction for soil amendment. The second route is the pyrolysis of pine wood waste and its direct combination with dried residual microalgae, also using it as soil amendment. The solid fraction assessment shows that from seven solid products (biochar) three stand out for their positive applicability in agriculture as soil amendment. In addition, they also present the benefit of serving as carbon sink, giving a negative balance of CO2 emissions. However, caution is suggested due to biochar applicability being subject to soil characteristics. To ensure the sustainability of the overall process, the energy available in liquid and gaseous fractions has been assessed for covering the drying needs of the residual microalgae in both cases. These results suggest that the pyrolysis process is a sustainable way to manage specific evaluated residues and their products.S

Scaling-Up of the Production of Biochar from Olive Tree Pruning for Agricultural Use: Evaluation of Biochar Characteristics and Phytotoxicity

[EN] Due to the large acreage of olive trees in the Mediterranean basin, the biochar from olive tree pruning may become an important resource as part of circular economy strategies. However, so far, there is not much knowledge on whether the same characteristics are repeated in biochar once production is up-scaled to an industrial level. Accordingly, this study aimed to scale up the production of olive tree pruning biochar with three reactors (semi-pilot, pilot and industrial) to ascertain the production parameters that determine the characteristics of the obtained biochar and its possible toxicity to use in agriculture or environmental applications. First, the production conditions in the semi-pilot reactor were optimised by testing three temperatures (400, 500 and 600 °C), with the result that 600 °C was the optimal production temperature because of a high carbon content (70.88%), moderate pH (8.1), good carbon sink (R50 > 0.5) and low contents of PAHs (<6 mg/kg) and heavy metals, resulting in a phytostimulanting effect for all the crops studied. Then, the production was upscaled, using 600 °C as pyrolysing temperature. At the industrial scale, accurate temperature control is essential because when temperatures above 650 °C were reached, the biochar showed a pH above 11, resulting in severe phytotoxicity. The longer retention time of the material in the industrial pyrolysers improved the carbon stability and, therefore, the biochar’s role as a carbon sink. Consequently, it was proven that it is possible to produce olive tree pruning biochar adequate for agriculture and environmental applications with large-scale equipment, and the two most important factors needing control are the temperature and retention time.SIThis research was co-funded by the research project “Desarrollo de fertilizantes avanzados a partir de subproductos del olivar y bioestimulantes microbianos” (BIFEROLIVA) [IDI-20191225] co-funded by Cortijo de Guadiana S.A. and CDTI (Spanish Ministry of Science and Innovation)

Codigestión Anaeróbica de Lodos y Residuos Orgánicos Municipales en Clima Tropical

La digestión anaeróbica permite la conversión de los lodos orgánicos provenientes de plantas de tratamiento de aguas residuales en fuentes de energía mediante la producción de biogás. Una manera de potenciar la producción obtenida mediante digestión anaeróbica es con la adición de otros sustratos al inóculo, mediante la codigestión anaeróbica. El objetivo de esta investigación fue evaluar el potencial energético de la codigestión de lodos y residuos orgánicos mediante la producción de metano, tomando en cuenta las propiedades fisicoquímicas de los materiales. Los ensayos de potencial de bioquímico de metano se llevaron a cabo mediante batch, mediante método manométrico utilizando el sistema Oxitop a una temperatura de 28°C por un tiempo de retención hidráulico de 10 días. Los ensayos de codigestión de Lodos orgánicos LD-LE resultaron con una producción de metano de 121.71mLCH4/g SV para la relación 1:1 y 154.84 mLCH4/g SV para la relación 2:1. Para la codigestion de LD-ROM se obtuvo una producción máxima de 294.92 mL CH4/g SV para la relación 1:1, mientras que para la relación 2:1 fue de 296.58 mL CH4/g SV. Los resultados obtenidos demuestran existen una disminución en el tiempo de retención hidráulico y el uso de lodo digerido como inóculo es positivo en la codigestión al reducir los tiempos de aclimatación

Proyecto de Emprendimiento para la creación de la micro empresa NATURINSUL, S.A. dedicada a la elaboración y comercialización de Té y Cápsula NATURINGUA a base de Costus Igneus (Insulina) y Annona Muricata (Guanábana) para personas con diabetes tipo II, ubicada en el municipio de Jinotepe, departamento de Carazo durante el II semestre del año 2019

El presente documento contiene un Proyecto innovador el cual analiza la rentabilidad de la apertura de una Micro empresa nombrada NATURINSUL, S.A. que se dedica a la producción y comercialización de NATURINGUA en dos presentaciones té y cápsulas como producto medicinal alternativo en los hogares del casco urbano de las ciudades de Jinotepe, Diriamba y San Marcos durante el II semestre del año 2019. Inicialmente se llevará a cabo un estudio de mercado en el cual se describirá la propuesta de proyecto identificando la rentabilidad y el grado de aceptación de los productos utilizando instrumentos para identificar la demanda insatisfecha, la oferta y la estrategia de mercado de manera que se proyecten las ventas. En la segunda parte se detalla a través de un plan de producción todo con respecto a lo técnico que necesitará para la apertura y seguimiento de las operaciones de la empresa, en este se detalla los procesos, las maquinarias necesarias, la disponibilidad de la materia prima y mano de obra esto para determinar los costos. En la tercera etapa se plantean todos los requerimientos legales para el correcto funcionamiento de NATURINSUL, S.A siendo muy importante la elaboración de un organigrama y dentro de que leyes se regirá la empresa, dentro de este plan organizacional se especifican cuáles son las funciones necesarias para formar un personal de trabajo capacitado para la producción y comercialización de la misma. En la cuarta y última parte se desarrolla un estudio financiero en el cual se detalla la inversión, los egresos, ingresos y costo que serán el resultado de la ejecución del proyecto, para conocer la rentabilidad en cuanto a la realidad financiera de la microempresa

Dietary Patterns and Dietary Recommendations Achievement From Latin American College Students During the COVID-19 Pandemic Lockdown

This study aimed to compare the diet quality of different dietary patterns among college students from Latin American countries, including vegetarians, vegans, and omnivores during the COVID-19 pandemic. A cross-sectional, observational, multicenter study was conducted including a non- probabilistic sample of university students from 10 countries. University students were invited to participate in the study through social network platforms. Participants were self-reported to have followed a specific dietary pattern; either the Prudent diet, Western diet, Ovo-dairy-vegetarian diet, Fish-vegetarian diet, Strict vegetarian diet (vegan) or other. The last three patterns (vegetarians and vegans) were grouped as following a plant-based diet. A self-assessment survey was used to evaluate healthy eating habits using a questionnaire with values between 1 (do not consume) and 5 (consume) for a total of 9–45 points (higher values represent better eating habits). Unhealthy habits were assessed with nine questions. A total of 4,809 students filled out the questionnaire, and the majority of them were females (73.7%). Murillo et al. College Dietary Patterns During COVID-19 A high percentage have been in lockdown for more than 5 months and were in lockdown when the survey was released. 74.3% were self-reported to follow a prudent diet, while 11.4% reported following a western dietary pattern and 8.8% a plant-based diet. When compliance with healthy and unhealthy dietary habits was analyzed, although all groups had low compliance, the plant-based diet group (56.09 ± 6.11) performed better than the Western diet group (48.03 ± 5.99). The total diet quality score was significantly higher for plant-based diet followers, who also tended to better achieve the recommendations than omnivorous students, especially the ones following a western diet. These results present evidence that young adults such as college-aged students have unhealthy dietary habits. However, the ones who follow a plant-based diet such as vegetarians and vegans exhibit better scores and healthier dietary conducts.UCR::Vicerrectoría de Docencia::Salud::Facultad de Medicina::Escuela de Medicin

Violencia familiar

Este libro reúne los pensamientos, las ideas, las propuestas y las experiencias en torno al tema de la violencia familiar de 20 autores sistémicos de habla hispana, entre ellos, algunos de los más reconocidos y destacados por sus contribuciones al paradigma en la posmodernidad. El contenido del texto, con los aportes de cada uno, ha sido cuidadosamente dispuesto por las editoras académicas, en una estructura que busca proporcionar a la complejidad del tema, un armonioso conjunto de los diferentes aspectos del fenómeno de la violencia