579 resultados para Carb?n
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Small off-road engines (SORE) have been recognised as a major source of air pollution. It is estimated that non handheld SORE annually produce over 1 million tonnes of HC+NOx and over 50 million tonnes of CO2. The fuel system design and its operating AFR are of key importance with regard to engine operation and engine out emissions. The conventional low-cost float carburettors used in these engines are relatively ineffective at atomising and preparing the fuel for combustion requiring a rich setting for acceptable functional performance. EPA and CARB have confirmed that Phase 3 limits are achievable for a “durable” engine fitted with a conventional well calibrated and manufactured “stock rich setting” float carburettor together with catalytic oxidation after-treatment and passive secondary air injection. The EPA and CARB strategy for meeting Phase 3 only considers the use of conventional float carburettors that operate at rich AFR’s over their entire engine operating range as no other cost effective alternative fuel system is yet available on the market. A cost effective alternative to the conventional carburettor that enabled leaner or optimised AFR operation with load and improved combustion performance would open the door to alternative strategies to meeting the phase 3 limits. This paper presents a completely new form of mechanical carburettor that gives AFR control with load, improved mixture preparation for improved combustion performance and has a lower production cost than conventional carburettors. The conventional and new fuel system designs and operation are discussed in detail and their technical merits demonstrated in the form of engine test data. The performance of different after-treatment systems is also simulated for different AFR profiles with load for a conventional or unmodified SORE engine. With optimised leaner operation and improved combustion characteristics, this new carburettor technology can provide significant engine out CO and HC+NOx reductions on the J1088 test cycle without loss of functional performance. Depending on the chosen emissions control strategy, minimum engine out emissions or optimum engine AFR for oxidation or three-way after-treatment or another, this new carburettor technology can be easily calibrated to provide the desired engine operating AFR profile on the J1088 cycle.
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La unidad did??ctica, elaborada por el Seminario de Ciencias Naturales del CEP del Nal??n, se centra en un tema muy cercano a la poblaci??n de esa zona, eminentemente minera. El carb??n es parte de su cultura y presenta una propuesta de actividades, ligadas a contenidos como: origen del carb??n, tipo de carb??n de la zona, propiedades del mismo, aplicaciones, extracci??n e influencias sobre la salud, el medio ambiente y vida econ??mico-social, acabando con el an??lisis de la situaci??n de crisis a la que ha llegado el sector.Se plantea una exploraci??n de conocimientos previos y se proponen actividades de evaluaci??n. La unidad se complementa con 2 transparencias y 3 fichas de trabajo.
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Ramon Carbó-Dorca va néixer a Girona un dia de tardor de 1940 en què la ciutat es negava en les aigües dels seus rius. Començar la vida enmig d’una contingència com aquella l’ha dut a pensar —explica— que no paga la pena preocupar-se de segons quines coses. Carbó-Dorca estudia a través de la semblança molecular la relació entre l’estructura i les propietats de les molècules
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Entrevista en Ramon Carbó-Dorca sobre la semblança molecular quantica
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La evaluación de los riesgos existentes en un centro educativo es una parte clave del plan de prevención que se diseñará para afrontarlos, debe saberse qué riesgos hay, qué nivel de gravedad tienen y qué soluciones existen para afrontarlos. A partir de este conocimiento se podrá decidir cuando, cómo y con qué medios afrontarlos. El estudio ha consistido en recoger información significativa sobre todo lo relacionado con el trabajo (instalaciones, estructura, aparatos, condiciones ambientales, desarrollo de la tarea docente), analizarla y proponer actuaciones para hacer más seguro, cómodo y llevadero el puesto de trabajo. La recogida de información se ha hecho siguiendo una metodología estándar de evaluación global de riesgos.
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Attempts to reduce the energy consumed in UK homes have met with limited success. One reason for this is a lack of understanding of how people interact with domestic technology – heating systems, lights, electrical equipment and so forth. Attaining such an understanding is hampered by a chronic shortage of detailed energy use data matched to descriptions of the house, the occupants, the internal conditions and the installed services and appliances. Without such information it is impossible to produce transparent and valid models for understanding and predicting energy use. The Carbon Reduction in Buildings (CaRB) consortium of five UK universities plans to develop socio-technical models of energy use, underpinned by a flow of data from a longitudinal monitoring campaign involving several hundred UK homes. This paper outlines the models proposed, the preliminary monitoring work and the structure of the proposed longitudinal study.
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An experiment was conducted to investigate the effects of increasing the level of two sources of fibrous by-products, orange pulp (OP) and carob meal (CM), in iso-NDF growing-finishing pig diets on nutrient balance, slurry composition and potential ammonia (NH3) and methane (CH4) emissions. Thirty pigs (85.4 ± 12.3 kg) were fed five iso-nutritive diets: a commercial control wheat/barley (C) and four experimental diets including two sources of fibrous by-products (OP and CM) and two dietary levels (75 and 150 g/kg) in a 2 × 2 factorial arrangement. After a 14-day adaptation period, faeces and urine were collected separately for 7 days to measure nutrient digestibility and the excretory patterns of N from pigs (6 replicates per diet) housed individually in metabolic pens. For each animal, the derived NH3 and CH4 emissions were measured in samples of slurry over an 11- and 100-day storage periods, respectively. Source and level of the fibrous by-products affected digestion efficiency in a different way as the coefficients of total tract apparent digestibility (CTTAD) for dry matter (DM), organic matter (OM), fibre fractions and gross energy increased with OP but decreased with CM (P < 0.05). Crude protein CTTAD decreased with the inclusion of both sources of fibre, being lower at the highest dietary level. Faecal concentration of fibre fractions increased (P < 0.05) with the level of inclusion of CM but decreased with that of OP (P < 0.01). High dietary level for both sources of fibre increased (P < 0.02) CP faecal content but urine N content decreased (from 205 to 168 g/kg DM, P < 0.05) in all the fibre-supplemented compared to C diet. Additionally, the proportions of undigested dietary, water soluble, and bacterial and endogenous debris of faecal N excretion were not affected by treatments. The initial slurry characteristics did not differ among different fibre sources and dietary levels, except pH, which decreased at the highest by-product inclusion levels. Ammonia emission per kg of slurry was lower in all the fibre-supplemented diets than in C diet (from 2.44 to 1.81 g, P < 0.05). Additionally, slurries from the highest dietary level of by-products tended (P < 0.06) to emit less NH3 per kg of initial total Kjeldahl N and showed a lower B0, independently of the fibre source. Thus, the fibre sources and their dietary levels affected pig nutrient digestion and composition of urine and faeces, showing potential to decrease NH3 and CH4 emissions at high levels of inclusion, independently of type of fibre.
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Mode of access: Internet.
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Mode of access: Internet.
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Tesis Universidad Central, 1858.
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Thesis (doctoral)--
