La participación social es una clave esencial para poder transformar el mundo a la medida de las necesidades de la humanidad. Sin ella, el futuro será más infeliz y oscuro para la inmensa mayoría de personas. Pero la participación, para ser constructiva, requiere de valores, actitudes, conocimientos, habilidades y competencias que la hagan posible. Y la escuela, la comunidad educativa y su entorno comunitario, son espacios idóneos para iniciar los aprendizajes necesarios que continuarán a lo largo de toda la vida. Este libro se ocupa de la Educación para la Participación desde la Escuela y su entorno.

Abstract: Dissolved air flotation (DAF) is considered better than conventional gravity settling (CGS) for the treatment of algal-laden waters, and ballasted sedimentation (BS), a high-rate separation process, is now often used instead of CGS. Our initial literature search did not identify DAF-BS comparisons for the removal of algae and cyanobacteria from algal laden waters. The objective of this benchscale study was to compare DAF with BS and CGS for the treatment of water from a eutrophic waterway (Bay of Quinte, ON). The study was performed mid-summer when there was substantial algal growth. The optimized BS jar tests had 3% lower average turbidity removal than the DAF jar tests, however BS required 33% more coagulant, as well as 0.25 mg/L anionic polymer and microsand additions. The removal of cyanobacteria and algae (quantified using chlorophyll-a and c-phycocyanin concentrations) by DAF and BS were very similar, and they were superior to that achieved by CGS. The DOC removals and the disinfection by-products formation potential (DBPFP) of DAF and BS treated water were also similar. Based on the chlorophyll-a and c-phycocyanin removals, both BS and DAF performed better than CGS and can be considered suitable for the treatment of algal/cyanobacteria laden waters.

Abstract: The aim of this research was to investigate the combustion behaviour of coal and biomass blends using a pilot-scale bubbling fluidised bed reactor. The blends were prepared with a traditionally used biomass fuel (i.e. wood) and selected rich in alkali-metals biomass fuels (i.e. wheat straw and spent coffee grounds (SCG)) to investigate the potential of SCG as a fuel and the effect of ilmenite on agglomeration tendency when used as an additive and alternative bed material. To elucidate the interaction between the fuels in the blends and the effect of ash composition, thermogravimetric and ash fusibility studies were performed looking at both the parent fuels and blends. Initially, thermogravimetric studies focused on understanding the thermal decomposition of coal blended with by-products (spent coffee ground (SCG), and coffee husk (CH)) of coffee crop. Blends with wood were included for comparison purpose. The blends were prepared by blending coal with biomass at 10, 30 and 50 wt%. The experiments were performed under inert and oxidising conditions to elucidate the thermal behaviour and fuel interactions. The results showed that the inclusion of either spent coffee grounds or coffee husk in coal combustion can enhance the combustion performance. Indeed, the blends with spent coffee grounds were found to be more reactive than those with coffee husk and with similar characteristics to the blends with wood. It was attributed to the existence of synergistic effects. These results offer compelling evidence of the potential of by-products from the coffee crop, especially spent coffee grounds for energetic applications. The study of ash fusibility characteristics investigated the ash fusibility temperatures under oxidising conditions of coal ash blended with ash from spent coffee grounds. Blends with wheat straw ash were included for comparison purpose. Particular attention was paid to the blending ratio effect on ash fusibility temperatures. The results showed that SCG is an interesting fuel in co-processing due to the low ash content and high ash fusibility temperatures when blended with coal. The high ash fusibility temperatures of the blends were attributed to the high content of CaO, MgO, and P2O5 in SCG with negligible content of SiO2 and Cl, complementing the high content of Al2O3 and Fe2O3 in coal. Evidence from this study suggests that the high ash fusion temperatures in the blends of coal with spent coffee grounds can reduce the common operational issues related to biomass ash such as agglomeration. This can also provide confidence for large scale thermochemical conversion systems fuelled by such kind of coal and biomass blends to be able to maintain long-term stable operation. The final part of this research focused on co-combustion experiments in a pilot-scale BFB aiming to investigate the potential of SCG as a fuel, and ilmenite as an additive and alternative bed material. For comparison purpose blends of coal with wheat straw and wood pellets were also combusted in the same BFB reactor under similar combustion conditions. Similarly, kaolin and bauxite, and silica sand were compared to ilmenite when used as an additive and alternative bed material, respectively. The inclusion of biomass in coal combustion showed marked differences in the temperature profiles, gas emissions, and combustion performance. The results showed that coal and SCG blends can be combusted for energy applications with improved combustion efficiency compared to wheat straw and wood commercial pellets. Nevertheless, high N content in SCG represents a challenge in terms of NOx emissions that should be addressed.

Abstract: This study investigates the combustion characteristics of blends of bituminous coal (BC) with two by products of the coffee industry, spent coffee ground (SCG) and coffee husk (CH), at 10, 30, and 50 wt% using a thermogravimetric analyzer (TGA). For comparison purposes, blends of BC and wood pellets (WP) at the same mass ratios were also investigated. The thermal behavior and fuel interactions in the blends during combustion were characterized by the ignition index (Di), combustion index (S), and potential synergistic effects. The interactions between the materials in the blends led to an enhancement of up to 93.5% and 128.5% in Di, and 175.2% and 96.35% in S of the bituminous coal when blended at 50 wt% with SCG and CH, respectively. Furthermore, clear synergistic effects were observed with the combustion of BC-SCG blends, whereas the combustion of BC-CH blends did not show any appreciable synergistic effects.

Abstract: Adequate initial bolt preload is necessary to ensure the strength and stiffness of bolted connections. In this study, an experimental torque control method was used to determine the relationship between tightening torque and preload of nine Extended Hollo-Bolt (EHB) blind bolted connections to Concrete-Filled Steel Hollow Sections (CFSHS). In order to obtain the EHB nut factors, which allow to calculate the level of preload for any value of applied torque, torque versus preload curves were drawn based on the experimental results and curve fitting method was carried out. Bolt preload relaxation was also recorded for a period of 7 days while concrete hardening occurred. Additionally, a detailed 3D Finite Element (FE) model of the tightening stage of the EHB was established. The experimental and numerical results show that the nut factor for the EHB is higher than that of standard bolts and bolt relaxation is not affected by the concrete presence during the hardening stage. Adequate friction coefficients were proposed as well as an equation for calculating the residual preload of the EHB. Resumen: Es necesaria una precarga inicial adecuada del perno para garantizar la resistencia y rigidez de las conexiones atornilladas. En este estudio, se utilizó un método experimental de control de torque para determinar la relación entre el torque de apriete y la precarga de nueve conexiones empernadas ciegas Extended Hollo-Bolt (EHB) a secciones huecas de acero rellenas de concreto (CFSHS). Para obtener los factores de tuerca EHB, que permiten calcular el nivel de precarga para cualquier valor de torque aplicado, se dibujaron curvas de torque versus precarga con base en los resultados experimentales y se llevó a cabo el método de ajuste de curvas. También se registró la relajación de la precarga de los pernos durante un período de 7 días mientras se producía el endurecimiento del hormigón. Además, se estableció un modelo 3D detallado de elementos finitos (FE) de la etapa de apriete del EHB. Los resultados experimentales y numéricos muestran que el factor de tuerca para el EHB es mayor que el de los pernos estándar y la relajación del perno no se ve afectada por la presencia del concreto durante la etapa de endurecimiento. Se propusieron coeficientes de fricción adecuados así como una ecuación para calcular la precarga residual del EHB.

Abstract: Fluid storage capacity measurements of core plugs in the laboratory consider pore volume as a function of effective stress. The latter is equal to applied confining pressure – n × applied pore pressure. However, the results are often reported as a function of difference in the applied pressures, because the effective stress coefficient (n) is an unknown. This creates confusion during the interpretation of laboratory data and leads to added uncertainties in the analysis of the storage capacity of the samples under in-situ conditions. In this paper, we present a new laboratory method that allows simultaneous prediction of the sample pore volume, the coefficient of isothermal pore compressibility, and the effective stress coefficient. These quantities are necessary to predict the fluid storage as a function of effective stress. The method requires two stages of gas (helium) uptake by the sample under confining pressure and pore pressure and measures pressure-volumedata. Confining pressure is always kept larger than the equilibrium pore pressure, but their values at each stage are changed arbitrarily. The analysis is simple and includes simultaneous solutions of two algebraic equations including the measured pressurevolumedata. The model is validated by taking the reference pore volume near zero stress. The reference volume predicted matches with that measured independently using the standard helium porosimeter. For sandstone, shale, and carbonate samples, the estimated pore compressibility is, on average, 10−6 psi−1. The effective stress coefficient is higher than unity and is a linear function of the ratio of the applied pressure values. We present a new graphical method that predicts the Biot coefficient (α) of the rock sample, a fundamental quantity used during the strain calculations that indicates the tendency of the rock to deform volumetrically. A new fundamental rule is found between the applied pressure difference and the effective stress: σe/α = pc − pp. Interestingly, the predicted Biot coefficient values for the shale samples show values between 0.46 and 1.0. This indicates that features of the shale sample, such as mineral variability, fine-scale lamination, and fissility, come into play during the fluid storage measurements. Resumen: Las mediciones de capacidad de almacenamiento de fluidos en tapones de núcleo en el laboratorio consideran el volumen poroso como una función del esfuerzo efectiva. Esta última, es igual a la presión de confinamiento aplicada - n × presión de poro aplicada. Sin embargo, los resultados a menudo se reportan como función de la diferencia en las presiones aplicadas, porque el coeficiente de esfuerzo efectivo (n) es desconocido. Esto crea confusión durante la interpretación de los datos de laboratorio y genera incertidumbres adicionales en el análisis de la capacidad de almacenamiento de las muestras en condiciones in situ. Resumen: En este artículo, presentamos un nuevo método de laboratorio que permite la estimación simultánea del volumen poroso de la muestra, el coeficiente de compresibilidad de poro isotérmico y el coeficiente de esfuerzo efectivo. Estas cantidades son necesarias para predecir el almacenamiento de fluido en función del esfuerzo efectivo. El método requiere dos etapas de absorción de gas (helio) por la muestra bajo presión de confinamiento y presión de poro y mide los datos de presión-volumen. La presión de confinamiento siempre se mantiene mayor que la presión de poro de equilibrio, pero sus valores en cada etapa pueden cambiar arbitrariamente. El análisis es simple e incluye soluciones simultáneas de dos ecuaciones algebraicas, incluidos los datos de presión-volumen medidos. El modelo se valida tomando el volumen de poro de referencia cerca de la tensión cero. El volumen de referencia estimado coincide con el medido de forma independiente utilizando un porosímetro de helio estándar. Para las muestras de arenisca, lutita y carbonato, la compresibilidad de poro estimada es, en promedio, 10−6 psi − 1. El coeficiente de esfuerzo efectivo es mayor a la unidad y es una función lineal de la relación de los valores de presión aplicados. Presentamos un nuevo método gráfico que predice el coeficiente de Biot (α) de la muestra de roca, una cantidad fundamental utilizada durante los cálculos de deformación que indica la tendencia de la roca a deformarse volumétricamente. Se encuentra una nueva relación fundamental entre la diferencia de presión aplicada y el esfuerzo efectivo: σe / α = pc - pp. Curiosamente, los valores del coeficiente de Biot estimado para las muestras de lutitas muestran valores entre 0,46 y 1,0. Esto indica que las características de la muestra de lutita, como la variabilidad mineral, la laminación a escala fina y la fisibilidad, entran en juego durante las mediciones de almacenamiento de fluidos.

Abstract: Essential Tremor (ET) is the most frequent movement disorder in adults. Upper-limb exoskeletons are a promising solution to alleviate ET symptoms. We propose a novel wrist exoskeleton for tremor damping. The TuMove exoskeleton is light-weight, portable, easy to use, and designed for ADLs and activities requiring hand dexterity. We validated the effectiveness of our exoskeleton by inducing forearm tremors using TENS on 5 healthy subjects. Our results show that wrist ranges are generally kept in most of the ROM needed in ADLs. The damping system reduced more than 30% of the tremor's angular velocity during drinking and pouring tasks. Furthermore, the completion time of the Archimedes spiral was decreased by 2.76 seconds (13.0%) and for the 9-Hole-Peg-Test by 2.77 seconds (11.8 %), indicating a performance improvement in dexterity tasks.

Resumen: Los puentes atirantados son una tipología muy eficiente que posee agradables atributos estéticos. En los últimos años ha emergido como el sistema dominante para puentes de grandes luces, hasta 1200 m gracias a la combinación de distintos avances tecnológicos que la han convertido en muy competitiva. Aparte de la estabilidad aerodinámica, para esta tipología es relevante el estudio de la estabilidad del equilibrio elástico global y local del tablero frente a las cargas de compresión que se generan por el esquema de atirantamiento. En este trabajo se presenta un estudio paramétrico en puentes atirantados que permite identificar y evaluar un rango de luces donde los fenómenos de inestabilidad global del tablero son significativos. Para lograr este análisis se plantean varios objetivos, inicialmente de estudio, luego de modelación e identificación de rangos y finalmente de análisis y conclusiones. Los temas estudiados para el estado del conocimiento son la evolución del proyecto de tableros de puentes atirantados metálicos y mixtos en función de la luz, así como la tipología de tableros en función de la luz del tablero frente a los fenómenos de inestabilidad global. Para la modelización del tablero se considera el modelo de viga sobre cimentación elástica o modelo de Winkler con módulo de reacción constante y variable, junto con esfuerzos axiles de variación constante y variable. Con los resultados obtenidos se identifican rangos de luces donde la inestabilidad es importante para el análisis, al cual se le evalúan sus efectos no lineales y su posible repercusión en el proyecto del tablero.

Abstract: In the present work, theoretical and experimental analysis of the thermal performance of flat plate pulsating heat pipes, made of copper, are presented. The pulsating heat pipes were manufactured using an innovative fabrication process for this application, the diffusion bonding. For this purpose, a special oven was used, available in Labtucal, that provides high temperature, high pressure and high vacuum conditions, which allows the fabrication of monolithic pieces with high reliability. Plates of equal external size were used, in which the internal channels were modified. Different geometries were applied, including the variation of the number of channels for the same overall dimensions (density increase), modifications of the surface finishing (roughness) and addition of lateral grooves at evaporator section. Flat plate pulsating heat pipes were tested under different operating conditions, such as tilt angles, heat input levels, and filling ratios, concluding that higher roughness or grooves at evaporator zone enhance the thermal performance of the devices, as start-up time, thermal resistance and thermal stability. However, the most relevant parameters, to decrease the dependence of the gravity in the operation of the pulsating heat pipe, are the number of channels and the working fluid filling ratios. A mathematical model, based on electrical circuit analogy, is constructed, taking into consideration the activation energy. Model validation was made with the experimental date obtained from the devices developed in this thesis. The model presented a maximum error of 25-30%, at vertical bottom heat mode and vertical top heat mode. The main contributions of this Ph.D. thesis are: the development of modified pulsating heat pipes using effective thermal improvements; the production of a reliable fabrication process compatible with the proposed thermal enhancements and, finally, a model that can be used as a design tool for pulsating heat pipes fabricated from machined plates. Resumen: En el presente trabajo, se realiza un análisis teórico y experimental del desempeño térmico de tubos de calor pulsantes de placa plana, fabricados en cobre. Los tubos de calor pulsantes fueron fabricados utilizando un proceso de fabricación innovador para esta aplicación, la difusión vinculación. Para ello se utilizó un horno especial, disponible en Labtucal, que proporciona alta temperatura, alta presión y alto vacío, lo que permite la fabricación de piezas monolíticas de alta confiabilidad. Se utilizaron placas de igual tamaño externo, en las que el Se modificaron los canales internos. Se aplicaron diferentes geometrías, incluyendo la variación de el número de canales para las mismas dimensiones generales (aumento de densidad), modificaciones del acabado superficial (rugosidad) y adición de ranuras laterales en la sección del evaporador. placa plana Los tubos de calor pulsantes se probaron en diferentes condiciones de funcionamiento, como ángulos de inclinación, calor suministrado, relaciones de llenado, concluyendo que una mayor rugosidad o ranuras en la zona del evaporador mejora el rendimiento térmico de los dispositivos, como el tiempo de inicio de operación, la resistencia térmica y la estabilidad de la temperatura. Sin embargo, los parámetros más relevantes, para disminuir la dependencia de la gravedad en el funcionamiento del tubo de calor pulsante, fueron el número de canales y las proporciones del llenado de fluido de trabajo. Se construye un modelo matemático, basado en la analogía del circuito eléctrico, tomando en Consideración la energía de activación. La validación del modelo se realizó con los datos experimentales obtenidos a partir de los dispositivos desarrollados en esta tesis. Las principales contribuciones de este doctorado tesis son: el desarrollo de tubos de calor pulsantes modificados utilizando mejoras térmicasla producción de un proceso de fabricación confiable y un modelo que se puede utilizar como herramienta de diseño.

Abstract: Perennial ryegrass (Lolium perenne) is the predominant forage crop in the equatorial highland zones of Colombia due to its high nutritional value and versatility to produce both milk and meat. This study aimed to determine the relationship between the relative depletion of usable soil water and the Ks values of canopy expansion and closure stomatal of perennial ryegrass, as well as to identify the threshold values of water stress. The experiment was carried out in pots under a controlled environment condition. These pots were arranged in a completely randomized manner. The experiment consisted of five treatments—including control treatment—of water deficits in the soil that progressively increased the depletion level as the crop cycle developed. This generated a wide range of conditions in the growth stages. For each treatment, four repetitions were performed Biomass production was significantly affected by water stress. The results show that the upper and lower thresholds of Ks were 0.28 and 1.3 of the depletion level (p) of the total available water (TAW) in the soil for the expansion of the canopy (CE), and 0.25 and 1.1 p of the TAW for stomatal closure (gs). Quadratic functions were fitted for both the CE (R2 = 0.72) and CS (R2 = 0.73); moreover, the Ks function of FAO-AquaCrop with positive shape factor (sf) was as follows: sf = 11, RMSE 0.22 for CE, and sf = 4.3, RMSE 0.19 for gs. Our results indicate that ryegrass is moderately sensitive to water stress. The differences found between the Ks function of FAO and the experimental data call for the need to use modeling with parameters adapted for each case. Resumen: El raigrás perenne (Lolium perenne) es el cultivo forrajero predominante en las zonas altas ecuatoriales de Colombia debido a su alto valor nutricional y versatilidad para producir tanto leche como carne. Este estudio tuvo como objetivo determinar la relación entre el agotamiento relativo del agua utilizable del suelo y los valores de Ks de la expansión del dosel y el cierre estomático del raigrás perenne, así como identificar los valores de los umbrales de estrés hídrico. El experimento se llevó a cabo en macetas en condiciones de ambiente controlado. Estas macetas se dispusieron de forma completamente aleatoria. El experimento consistió en cinco tratamientos, incluido el tratamiento de control, de déficit de agua en el suelo que aumentaron progresivamente el nivel de agotamiento a medida que se desarrollaba el ciclo del cultivo. Esto generó una amplia gama de condiciones en las etapas de crecimiento. Para cada tratamiento se realizaron cuatro repeticiones. La producción de biomasa se vio significativamente afectada por el estrés hídrico. Los resultados muestran que los umbrales superior e inferior de Ks fueron 0.28 y 1.3 del nivel de agotamiento (p) del agua total disponible (AAT) en el suelo para la expansión del dosel (ED), y 0.25 y 1.1 p del AAT para cierre de estomas (gs). Se ajustaron funciones cuadráticas tanto para ED (R2 = 0,72) como para cierre de estomas gs (R2 = 0,73); además, la función Ks de FAO-AquaCrop con factor de forma positivo (Ff) fue la siguiente: Ff = 11, RMSE 0,22 para ED y Ff = 4,3, RMSE 0,19 para gs. Nuestros resultados indican que el raigrás es moderadamente sensible al estrés hídrico. Las diferencias encontradas entre la función Ks de FAO y los datos experimentales hacen necesaria la utilización de modelos con parámetros adaptados a cada caso.