Investigation of the factors influencing the efficiency of a solar still combined with a solar collector

A solar still was designed for the evaporation of desalination brine. The influence of several factors, such as the basin heating, the material of the cover (glass or polycarbonate), the existence of a mirror, the activation of an air extractor, and the existence of a black painted floor in the solar still, was evaluated in terms of their contribution to brine evaporation. The experiments were conducted with a factorial design approach. The combination of the factors that produced the best results was used in a subsequent daily monitoring study for brine evaporation. The monitoring parameters were the hourly average incident radiation, the changes in the temperature, the brine mass, and the brine volume. The accumulated amounts of the solar energy were calculated, and the correlation relationship was assessed.Regional Government of Coquimbo - 30137726-

Tiempo de reflexiones, una oportunidad del mundo

Este ensayo propone recorrer e indagar la relación entre el tiempo y las personas, reflexionando acerca de las diferentes representaciones, y como el sistema neoliberal se ha desarrollado dentro de esta relación, delimitando un camino que recorrer, así alienando el devenir de las personas y sus prácticas.El nuevo contexto planteado a nivel mundial por la pandemia (COVID 19) exige más que nunca reflexionar acerca de esto, sosteniendo a la recreación como una oportunidad, el pensamiento crítico como una herramienta que interpela lo contextual de nuestras prácticas y al juego como un posible camino trasgresor al sistema capitalista

Tratamento de lixiviado de aterro sanitário com carvão ativado obtido de resíduos de café

A set of experiments were carried out in order to establish and evaluate the potential of activated carbon, produced from coffee waste in adsorption process, in the depuration of landfill leachate. Different reagents were studied in the activation of carbon: HCl, HCl + H2O2, H3PO4, H3PO4 + H2O2, all with an impregnation rate of 1:1. The activated carbon that showed the best global results was activated with H3PO4, obtaining a 51.0, 32.8, 66.0, 81.0 and 97.1% elimination of chemical oxygen demand, ammonia, total chlorine, bromine and copper, respectively. This activated carbon has a total pore area of 4.85 m2/g and a median pore diameter of 65.32 micrometers. When different loads of this carbon were placed in a stirrer system in contact with landfill leachate, with the aim of evaluating the effect of the adsorption load and contact time, the concentration of ammonia decreased from the beginning of the adsorption process to the end of it, and the removal of ammonia increased with the increase in the adsorbent load. However, the trend of the amount adsorbed per unit mass decreased with increased dosage. The model Freundlich equilibrium isotherm fits experimental data adequately, giving R2 values of 0.95, 1/n of 0.5183, and a K value of 7.08*10-5 L/g, being favourable for adsorption process.Foi realizada uma série de experimentos para estabelecer e avaliar o potencial de carvão ativado produzido de resíduos de café por meio de um processo de adsorção na depuração do lixiviado de aterro sanitário. Foram estudados diferentes reagentes para a ativação do carvão: HCl, HCl + H2O2, H3PO4, H3PO4 + H2O2, todos com taxa de impregnação de 1:1. O carvão que apresentou os melhores resultados foi ativado com H3PO4, obtendo uma eliminação de 51,0; 32,8; 66,0; 81,0; e 97,1% de demanda química de oxigênio e concentração de amônia, cloro total, bromo e cobre, respetivamente. O referido carvão ativado tem uma área total de poro de 4,85 m2/g e diâmetro médio de poro de 65,32 micrômetros. Com o objetivo de avaliar o efeito da carga de adsorção e do tempo de contato, foram colocadas diferentes cargas desse carvão em um sistema de agitação em contato com o lixiviado de aterro sanitário. Observou-se que a concentração de amônia diminuiu e que sua remoção foi maior à medida que a carga adsorvente aumentava. No entanto, a quantidade adsorvida por unidade de massa diminuiu com o aumento da dosagem. Os dados experimentais adequaram-se corretamente ao modelo de isoterma de Freundlich, obtendo-se valores de R2 de 0,95, 1/n de 0,5183, e um valor de K de 7,08*10-5 L/g, considerados favoráveis para o processo de adsorção.Ministerio de Educación (Chile) 1114021

Integrated nutrient management as a sustainable strategy to recover a decayed Pear (Pyrus communis) orchard

Integrated Nutrition Management (INM) is a concept developed during the last decade in fruit agroecosystems based on the application of organic matter, biostimulants, and adjusted chemical fertilization to improve soil quality, plant rhizogenesis, and nutrition. Nevertheless, there are few studies on the application of the INM concept on the recovery of decayed orchards. The present study was focused on the evaluation of the effects of INM on soil and plant quality changes as recovery indicators of a decayed pear orchard. Two treatments (T1: conventional, T2: INM) were evaluated under three tree vigor levels, during two growing seasons. Old pear trees were used in a factorial experiment of two treatments (control and INM) x three vigor levels, based on a previous aerial Normalized Difference Vegetation Index (NDVI) image. Soil properties, nutrient leaf contents, and NDVI were evaluated. Soil chemical and biological properties and their spatial variability were determined after two and five years of treatment application, respectively. The INM improved β-glucosidase activity, reduced bulk density, and increased soil porosity. Furthermore, nutrient indices (NDVI x N, K, Ca, Mg, Cu, Fe, and B) were significantly increased under INM. After two years, soil chemical properties and root density were improved by INM. A significantly higher yield, soil organic matter, soluble C, and dehydrogenase activity was observed with INM after five growing seasons. The results indicated that INM is a sustainable alternative for recovering decayed orchards, through the inclusion of good-quality organic matter within the management program.Integrated Nutrition Management (INM) is a concept developed during the last decade in fruit agroecosystems based on the application of organic matter, biostimulants, and adjusted chemical fertilization to improve soil quality, plant rhizogenesis, and nutrition. Nevertheless, there are few studies on the application of the INM concept on the recovery of decayed orchards. The present study was focused on the evaluation of the effects of INM on soil and plant quality changes as recovery indicators of a decayed pear orchard. Two treatments (T1: conventional, T2: INM) were evaluated under three tree vigor levels, during two growing seasons. Old pear trees were used in a factorial experiment of two treatments (control and INM) x three vigor levels, based on a previous aerial Normalized Difference Vegetation Index (NDVI) image. Soil properties, nutrient leaf contents, and NDVI were evaluated. Soil chemical and biological properties and their spatial variability were determined after two and five years of treatment application, respectively. The INM improved β-glucosidase activity, reduced bulk density, and increased soil porosity. Furthermore, nutrient indices (NDVI x N, K, Ca, Mg, Cu, Fe, and B) were significantly increased under INM. After two years, soil chemical properties and root density were improved by INM. A significantly higher yield, soil organic matter, soluble C, and dehydrogenase activity were observed with INM after five growing seasons. The results indicated that INM is a sustainable alternative for recovering decayed orchards, through the inclusion of good-quality organic matter within the management program

Landfill leachate treatment using combined fish scales based activated carbon and solar advanced oxidation processes

The depuration of landfill leachate (LL) was evaluated by solar advanced oxidation processes (AOPs) (photo-Fenton + O3 and photo-Fenton + O2) and adsorption processes, using activated carbon made from fish scales, as either post-treatment or pre-treatment of advanced oxidation process. Also, the effect in the reduction of toxicity of LL depurated under these methods was evaluated. The activated carbon Brunauer-Emmett-Teller (BET) surface area is 1.8329 m2/g and the adsorption average pore width is 12.79833 nm, considered as a mesoporous material. When AOPs were used as treatment and adsorption was used as post-treatment of the LL, a removal of 67%, 98%, 98.9%, 83.3% and 99.6% of chemical oxygen demand (COD), colour, copper, iron and ABS254, respectively, was obtained. When the adsorption process was applied as AOP pre-treatment, the removal of organic matter was better in comparison to the results of the adsorption process as AOPs post-treatment. This resulted in a removal of COD, colour, copper, iron and ABS254 of 75.4%, 99.4%, 94.4%, 68.3% and 98.1%, respectively. When the AOPs were followed the adsorption process, a germination index (GI) of 126%, 122% and 116% was obtained. This was higher than the results obtained by LL treated with PF + O2 in a solution concentration of 1%, 3% and 10%, respectively. When PF + O3 was used at a concentration solution of 1%, 3% and 10%, similar GI values were obtained (122%, 113% and 114%, respectively). The EC50 is very low for raw LL, but this value increases as the LL is treated. A very high EC50 is obtained for the adsorption process and for AOPs following the adsorption process, going from 1.8 to 21.0 V/V. Adsorption as pre-treatment helps removing colour and metals from LL, thus enhancing the performance of solar AOPs

Eucalyptus nitens como materia prima para tableros de partículas

El objetivo del trabajo fue evaluar la madera de Eucalyptus nitens (Deane et Maiden) Maiden como materia prima para tableros de partículas. Se controlaron la densidad de la madera, las dimensiones de las partículas obtenidas, el coeficiente de esbeltez y el valor pH de las partículas. Se fabricaron tableros con densidades entre 450 y 750 kg/m³ y se determinaron las propiedades flexión, tracción perpendicular, densidad de los tableros, hinchamiento y absorción de agua a las 2 y 24 horas. Se calculó el grado de correlación de las distintas propiedades del tablero con la densidad de los mismos. Las características de la madera, de las partículas y las propiedades de los tableros demuestran que la madera de Eucalyptus nitens es apta para ser utilizada en la fabricación de estos aglomerados. A medida que aumenta la densidad del tablero se provoca un aumento en las propiedades mecánicas. El hinchamiento y la absorción de agua mejoran con aumentos de la densidad. El análisis de correlación entre las propiedades dependientes (hinchamiento, absorción, flexión y tracción) y la densidad del tablero arrojó coeficientes de correlación mayores a 0,7. La propiedad crítica es el hinchamiento, por lo que se recomienda agregar una emulsión de cera y un catalizador en el adhesivo de la capa central. AbstractThe aim of the study was to evaluate Eucalyptus nitens as raw material for the production of particleboards. Wood density and particle size, slenderness and pH-value were controlled. Bending strength, internal bond, density, thickness swelling and water absorption after 2 and 24 hours of particleboards with densities between 450 and 750 kg/m³, were determined. Correlations between board density and properties were calculated. The wood and particle characteristics as well as the obtained board properties proved that Eucalyptus nitens could be used for the particleboard production. As board density increases, higher mechanical properties were founded. Thickness swelling and water absorption decreased as density of particleboard increased. High correlation factors (> 0,7) between dependent variables (thickness swelling, absorption, bending strength and IB) and board density were obtained. Due to swelling is a critical property, we recommend the addition of a wax emulsion and a catalyst in the middle layer of the particleboard

Educación Física en la infancia : Experiencia de una propuesta didáctica en la escuela

El siguiente trabajo presenta una propuesta práctica de enseñanza de la educación física (en adelante EF) para la infancia, llevada a cabo en una institución educativa de la ciudad de Viña del Mar, Chile. Lo lúdico, a partir del compartir y cooperar, el descubrimiento de las posibilidades de autonomía, libertad y resolución, individual y colectiva de problemas, son las características metodológicas de la misma, construyendo un ambiente propicio para el aprendizaje. El trabajo, se articula a través de cinco lineamientos didácticos: la tarea como una propuesta, jerarquización de las mismas, variabilidad, ludismo, y toma de decisiones a partir de la resolución de problemas. Desde el punto de vista investigativo se trabaja con un diseño mixto. Desde la lógica pre y post test conocimos la incidencia de la propuesta en los niños 2 participantes, utilizando una pauta de observación de habilidades motrices (Vargas, 2004). Paralelamente se construyeron dos cuestionarios de preguntas abiertas y una entrevista con el que pudimos analizar las percepciones de los participantes. La muestra fue intencionada, compuesta por un grupo intacto de niños de 4 años de edad. Los datos cuantitativos fueron analizados con un método estadístico no paramétrico (T Student) a través del software SPSS 19.0. Cualitativamente realizamos análisis de contenido y de discurso de carácter mixto inductivo deductivo, apoyados con el software Nvivo 8.0. De los hallazgos se destaca un desarrollo de las habilidades motrices y una valoración positiva hacia la propuesta por parte de quienes participaron de ell

Biological Materials: Materials and Sustainability through Design

El siguiente artículo tiene como objetivo destacar la importancia y el vínculo entre los conceptos de sustentabilidad, nuevos materiales biológicos y circularidad a través del diseño. Al hacer hincapié en los materiales biológicos como un camino posible a un cambio de paradigma, se pretende poner en discusión el sistema económico nacional actual, que resalta el desarrollo de estos como un fenómeno posible dentro del país. A su vez, y haciendo énfasis en los conceptos mencionados, este artículo pretende demostrar el valor que tiene hoy la función del diseñador como agente de influencia en la sociedad y en la producción de bienes.The following article aims to highlight the importance and the connection between the concepts of sustainability, new bio-based materials and circularity through design. By emphasizing bio-based materials as a possible path to shift the paradigm, bringing to discussion the current national economic system, pointing out its development as a feasible phenomenon capable of being implemented. Moreover, what this article aims to demonstrate highlighting the mentioned concepts is the value of the designer’s role today as an agent of influence in society and in the production of goods.Facultad de Arte

“La influencia de las estrategias cognitivistas en el aprendizaje de Ciencias Naturales para 5º año básico”

59 p.La presente tesis se dirige a atender unos de los problemas más frecuentes de la enseñanza de las ciencias naturales, que es cómo desarrollar y mejorar las habilidades científicas desde los primeros años escolares, en este caso con los estudiantes de quinto año básico.En lo que respecta al objetivo general de esta investigación será: Conocer las estrategias de enseñanza que favorecen el aprendizaje de los estudiantes de 5º básico de la Escuela Municipal de San Javier, en la asignatura de Ciencias Naturales y como objetivos generales: Analizar las estrategias que colaboran en el aprendizaje de Ciencias Naturales; Describir las estrategias que ayudan a mejorar el rendimiento de los estudiantes en los estudios superiores y por último Conocer los diferentes tipos de estrategias que favorecen el desarrollo de competencias en Ciencias Naturales. Cada uno objetivos responden a las preguntas o interrogantes que se formularon en el diagnóstico.En cuanto al modelo empleado, es cualitativo correspondiendo al diseño etnometodológico, por medio del estudio descriptivo. Utilizándose como instrumento de recogida de datos: la entrevista al estamento docente. Tras el diagnóstico y como problema de estudio, se detectó el deficiente rendimiento de los estudiantes de quinto año básico, en la asignatura de Ciencias Naturales, específicamente en la Unidad “Estructura y función de los seres vivos”. Por lo que se indagó acerca de la Didácticas y estrategias cognitivistas que ayudan a un trabajo colaborativo y activo por parte de los estudiantes, debido a que la escuela municipal a pesar de de contar con recursos humanos y materiales no ha podido elevar las calificaciones de los estudiante. Posteriormente con el trabajo de campo se constató que los docentes de ciencias de este establecimiento, manejan en sus praxis pedagógicas, estrategias de corte magistral o conductista en contraposición de lo que establecen los Planes y Programas establecidos por el Ministerio de Educación de Chile