996 resultados para Silos (Agricultura)
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Una sitja és una cavitat subterrània destinada a emmagatzemar la collita, especialment de cereals. Amb el manteniment d'unes condicions ideal de temperatura i humitat els cereals s'hi poden conservar durant un llarg període de temps, que segons Varró podria arribar als 50 anys. Aquestes excepcionals possibilitats han possibilitat que l'emmagatzematge en sitges fos un dels mètodes de conservació de cereals a llarg termini més utilitzat en les societats pre-industrials de tot el món. La sitja estàndard del nord-est de Catalunya és aquella que era excavada a l'argila, no portava revestiment i tenia la boca en forma de tub, de 0,77 m de diàmetre màxim per 0,42 de profunditat. El perfil era de tipus còncau, amb el diàmetre màxim situat en el terç central de la sitja, i un fons indistintament còncau o pla. La profunditat i el diàmetre màxim es situarien entre 1,75 i 2 m., amb un marge de diferència reduïdíssim entre ambdues mesures. La capacitat resultant d'aquestes dimensions se situaria entre 1 i 3 tones de cereals, que en termes estàndards de producció seria el resultat de la collita d'una extensió d'entre 1,5 i 4 hectàrees de terreny. ASBTRACT: A silo is an underground cavity designed to store the harvest, especially grain. With the maintenance of ideal conditions of temperature and moisture grains can be preserved for a long period of time, according to Varró it could reach 50 years. These exceptional opportunities have enabled the storage silos to be one of the methods of long-term conservation of grain used in most pre-industrial societies around the world. The standard silo from the North-East of Catalonia was excavated in clay,it had no siding and its mouth was tube-shaped, up to 0.77 m of maximum diameter to 0.42 deep. The profile was concave, with maximum diameter located in the central third of the silo, and a background either concave or flat. The depth and maximum diameter are located between 1.75 and 2 m, with a very little margin of difference between the two measures. The capacity resulting from these dimensions would be located between 1 and 3 tons of cereals, which in terms of production standards it would mean a harvest of between 1.5 and 4 hectares of ground.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Pós-graduação em Agronomia (Energia na Agricultura) - FCA
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The use of Information and Communication Technology has grown in most agricultural activities. As a consequence, it has changed the way of thinking and acting of the farmer who wants to establish a more and more competitive market. However, the high costs of acquisition and maintenance of those technologies may be a factor which can inhibit its spread and acceptance, mainly to a large number of small grain Brazilian farmers. In this context, there is a need for innovative solutions that are proper for this universe of farmers. Starting from this premise, this paper presents the development of a low cost prototype to the monitoring process of temperature and humidity values of grains stored in silos, using communication based on wireless technology by radio frequency. Therefore, the economic implications of cost/benefit ratio of innovative application of wireless transmission in the process of thermometry of grains were analysed. The prototype was made of two electronic units, one of acquisition and another one of data reception, as well as computational software, which offered the farmer more precise information for the control of aeration. By means of stability, integrity and reliability tests of data transmission via radio, using low cost electronic components, the development system can be considered as potentially viable. It presented the difference regarding the wireless communication via radio in the process of grains thermometry, providing mobility, reducing cabling costs and maintenance, and also offering an easy system expansion; it was also appropriate to temperature and humidity monitoring in grain silos; and revealed operational viability, besides the low cost development when compared to similar products available in the Brazilian market.
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El comportamiento de los materiales granulares almacenados en silos se ve afectado por varios parámetros, tanto aquellos característicos del material como de la geometría del silo. La determinación del coeficiente de rozamiento pared-partícula es uno de los parámetros de mayor importancia, siendo habituales en su determinación el uso de ensayos de corte directo. En el presente trabajo se estudia dicho coeficiente para el supuesto de una pared corrugada, el cual, teóricamente, debe representar a un valor efectivo que depende tanto del coeficiente de rozamiento grano-pared (para el caso de una pared lisa) y el ángulo de rozamiento interno del material. La determinación del rozamiento efectivo se ha realizado a través de la simulación por elementos discretos de un ensayo de corte sobre una pared corrugada. Los valores obtenidos han sido comparados con las prescripciones expuestas en la normativa vigente. La potencialidad del método de los elementos discretos permite el estudio de diversas configuraciones geométricas de la pared corrugada de los silos sin necesidad de realizar ensayos de laboratorio. Esto permitirá, en trabajos sucesivos, investigar la influencia de muy diversos factores en el valor del rozamiento efectivo grano-pared en este tipo de paredes. The mechanical behaviour of granular materials stored in silos is affected by numerous parameters, some of them being related to the characteristic of the stored materials and others to the geometry of the silo. The determination of the particle-wall friction coefficient (or wall friction) is of great importance and direct shear tests are usually conducted in order to obtain its value. In this work this variable is analysed for the case of a corrugated wall. This value is expected to be an effective value between the particle-wall friction coefficient (obtained for a flat wall) and the internal friction coefficient of the material under study. The effective wall friction determination has been carried out by using a discrete element model to simulate a direct shear test on a corrugated wall. The values obtained have been compared with prescriptions given in the current standards. The potential of the discrete element method allows different geometries of the silo corrugated wall to be considered without the necessity of developing laboratory tests. In future works it will allow the influence of numerous parameters on the effective wall friction in corrugated walls to be studied.
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Sign.: []4, B1, A2-A4, B-Z4-, 2A-2Z4, 3A-3N4
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Patient safety has become a significant and pressing policy issue. Around the world, governments, the health care sector and the public are increasingly cognizant of the need to improve the safety of care delivered by their health systems. Pressure for change has been created by highly publicized incidents in a number of countries involving unsafe acts that were significant both in scale and consequence and a number of empirical studies that revealed the high rates of unsafe acts and their consequences. The costs of unsafe health care – both personal and fiscal – to individuals, their families and their communities and to the state are massive. In this research project we explored one particular avenue for change – that is, the use of legal instruments by governments to improve patient safety. We did this through a comparative review of the use of legal instruments or frameworks in other countries (specifically Australia, Denmark, New Zealand, the United Kingdom, and the United States) as well as two non-health care related sectors in Canada (transportation and occupational health and safety). We began this research by reviewing the legal instruments and undertaking extensive literature reviews. Further information was gathered through in-person interviews with policy-makers and academics in the countries studied, and from policy-makers and academics expert in the health, occupational health and safety, and transportation sectors in Canada. Once descriptions of the various countries and sectors were drafted, we held small-group meetings with local experts on particular aspects of patient safety. We then hosted a national consultation meeting. We subsequently drafted this final report and the appendices, which fully describe the results of the background research. Finally, we prepared a summary version of the report as well as posters and papers to be published and delivered at conferences and meetings with relevant groups.
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The aim of this study was to examine the actions of geographically dispersed process stakeholders (doctors, community pharmacists and RACFs) in order to cope with the information silos that exist within and across different settings. The study setting involved three metropolitan RACFs in Sydney, Australia and employed a qualitative approach using semi-structured interviews, non-participant observations and artefact analysis. Findings showed that medication information was stored in silos which required specific actions by each setting to translate this information to fit their local requirements. A salient example of this was the way in which community pharmacists used the RACF medication charts to prepare residents' pharmaceutical records. This translation of medication information across settings was often accompanied by telephone or face-to-face conversations to cross-check, validate or obtain new information. Findings highlighted that technological interventions that work in silos can negatively impact the quality of medication management processes in RACF settings. The implementation of commercial software applications like electronic medication charts need to be appropriately integrated to satisfy the collaborative information requirements of the RACF medication process.
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The phosphine distribution in a cylindrical silo containing grain is predicted. A three-dimensional mathematical model, which accounts for multicomponent gas phase transport and the sorption of phosphine into the grain kernel is developed. In addition, a simple model is presented to describe the death of insects within the grain as a function of their exposure to phosphine gas. The proposed model is solved using the commercially available computational fluid dynamics (CFD) software, FLUENT, together with our own C code to customize the solver in order to incorporate the models for sorption and insect extinction. Two types of fumigation delivery are studied, namely, fan- forced from the base of the silo and tablet from the top of the silo. An analysis of the predicted phosphine distribution shows that during fan forced fumigation, the position of the leaky area is very important to the development of the gas flow field and the phosphine distribution in the silo. If the leak is in the lower section of the silo, insects that exist near the top of the silo may not be eradicated. However, the position of a leak does not affect phosphine distribution during tablet fumigation. For such fumigation in a typical silo configuration, phosphine concentrations remain low near the base of the silo. Furthermore, we find that half-life pressure test readings are not an indicator of phosphine distribution during tablet fumigation.
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The mass flow rate, (m) over dot, associated with the lateral outflow of dry, cohesionless granular material through circular orifices of diameter D made in vertical walls of silos was measured experimentally in order to determine also the influence of the wall thickness of the silo, w. Geometrical arguments, based on the outflow happening, are given in order to have a general correlation for (m) over dot embracing both quantities, D and w. The angle of repose appears to be an important characterization factor in these kinds of flows.
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La preocupante situación por el uso excesivo de productos químicos en granos almacenados, ha llevado a la búsqueda de métodos efectivos no químicos para prevenir las pérdidas ocasionadas por los insectos. Entre estos métodos tenemos el uso de atmósferas modificadas (AM) el cual ha sido utilizado en otros países con buenos resultados. Este método consiste en la descomposición o fermentación de materiales vegetales como substrato para la generación de CO2 (dióxido de carbono) en un biogenerador, conectado a silos metálicos u otros depósitos de granos herméticos donde el gas es transferido pasivamente al depósito de granos. Nos propusimos identificar fuentes naturales para la producción de CO2 y determinar la eficacia del método de atmósferas controladas en el control del Sitophilus zeamais Motsch. Para el estudio se realizaron dos etapas: Identificación de fuentes naturales para la producción de CO2 a partir del proceso de fermentación, donde se probaron caiia de azúcar, banano y maíz, utilizando para cada material tratamientos con y sin levadura comercial en concentración de 0.5% y 0% respectivamente de la cantidad total del material a fermentar en el biodigestor. Se determinó el momento inicial, máximo y final de la producción de CO2 . El tipo de biogenerador utilizado para todos los ensayos consistió de un depósito plástico de 18 l. de capacidad, donde se colocaron los materiales a fermentar. Se utilizó un indicador de agua. La variable a medir fue la emisión de burbujas en un período de tres minutos a intervalos de dos horas. Se determinó el porcentaje de mortalidad del S. zeamaiz en silos metálicos de 4qq. con maíz utilizando la AM. El silo metálico fue llenado con maiz hasta las 5/6 partes de su capacidad total; las jaulas que se utiüzaron fueron recipientes plásticos de 1L de capacidad con maíz-grano y 100 gorgojos del maíz adultos en su interior, colocadas a tres diferentes profundidades dentro del silo metálico. El porcentaje de C02 contenido en el silo metálico se midió con el método bioquímico del Hidróxido de Sodio (NaOH). El índice de mortalidad se evaluó a los 6, 8 y 10 días. Los mejores resultados en producción de gas se obtuvieron con el banano, con un rendimiento promedio de 91.9 y 52.6 burbujas por tres minutos a intervalos de dos horas en un período de 40 horas. Con un porcentaje mayor al 25% de CO 2 en el interior del silo metálico (atmósfera interna) y más de 6 días de exposición se obtuvo la mortalidad del gorgojo del maíz superior al 95%; concluyendo que la mortalidad del gorgojo del maíz estará en dependencia del porcentaje de CO2 en el interior del silo metálico.
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El presente artículo es producto de la investigación "Caracterización socio-económica de la microcuenca Cuscamas, El Tuma-La Dalia" realizada en el 2001, cuyo propósito fue describir y analizar los aspectos socioeconómicos y productivos, y la manera de cómo éstos se relacionan con el manejo y aprovechamiento de los recursos naturales. El método utilizado fue el estudio de caso. Para obtener la información requerida se usaron encuestas, observación directa. transeptos, talleres y entrevistas con informantes claves. Los resultados señalan que la actividad principal de las familias es la agricultura. ya que genera directa o indirectamente ingresos y alimentos. La diferencia entre los sistemas productivos encontrados radica en las estrategias de vida: algunos pueden establecer mas áreas de cultivos que otros, aplicar mas o menos insumos y destinar mas o menos producción al mercado, vender o no su fuerza de trabajo, en dependencia de su nivel de bienestar. El análisis de este caso indica que los campesinos dependen directamente o indirectamente de la agricultura para obtener sus alimentos e ingresos; sin embargo, no debe esperarse que esta pequeña agricultura sea suficiente para salir de la situación de pobreza por el contrario, se requiere una estrategia integral de desarrollo rural que contenga de manera equilibrada elementos de agricultura familiar, diversificación productiva, comercio justo, empleo rural no agrícola. bienestar o protección social, agroindustria y empoderamiento.
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A partir del 12 de octubre de 1492, el mundo ya no fue el mismo. El almirante Cristóbal Colón tocada tierras de un nuevo continente, al que llamaría América. Cuando descubrió Las Antillas, encontró que estas islas estaban habitadas por diversas tribus donde la agricultura era el epicentro de sus vidas, de sus usos y costumbres. De ella se han heredado muchas y se encuentran vigentes de uso cotidiano. El presente trabajo hace descripción de algunas de estas vigencias y se citan ejemplos de su variada influencia como los nombres de: maní (Arachis hypogea L.), maíz (lea mays L.) guanábana (Annona muricata L.), pitahaya (Hyfocereus undatus B & G) y tabaco (Nicotiana tabacum L.), en usos particulares en el caso del mamey (Mammea americana L.), icaco (Chysobafanus icaco L.) y yuca (Manihot esculenta C.), con propósito alimenticio el quequisque (Xanthosoma sagittifolium Shott), batata (lpomoea batatas L.) y topee tambo (Caffathea affonia) y de origen autóctono como la piña (Ananas comosus L.), nancite (Byrsonima crassifolia H.B.K.), guayaba (Psidium guajava L.), coco (Cocos nucifera L.), caímito (Chysophylum caimito L.), guayacán (Guayacum sanctum L.) y la caoba ( Swietenia microphyfa L.).