22 resultados para Principle of alternative possibilities
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Analysis of oxy-fuel combustion as an alternative to combustion with air in metal reheating furnaces
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Using oxygen instead of air in a burning process is at present being widely discussed as an option to reduce CO2 emissions. One of the possibilities is to maintain the combustion reaction at the same energy release level as burning with air, which reduces fuel consumption and the emission rates of CO2. A thermal simulation was made for metal reheating furnaces, which operate at a temperature in the range of 1150-1250 degrees C, using natural gas with a 5% excess of oxygen, maintaining fixed values for pressure and combustion temperature. The theoretical results show that it is possible to reduce the consumption of fuel, and this reduction depends on the amount of heat that can be recovered during the air pre-heating process. The analysis was further conducted by considering the 2012 costs of natural gas and oxygen in Brazil. The use of oxygen showed to be economically viable for large furnaces that operate with conventional heat recovering systems (those that provide pre-heated air at temperatures near 400 degrees C). (C) 2014 Elsevier Ltd. All rights reserved.
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O uso de fontes não convencionais para fornecimento de K às plantas tem sido amplamente estudado, mas os efeitos de materiais alternativos na qualidade fisiológica das sementes não são conhecidos. Este estudo teve como objetivo avaliar a qualidade fisiológica de sementes de soja e trigo em função da aplicação fontes de potássio em uma sucessão de culturas. O delineamento experimental foi o de blocos ao acaso com quatro repetições. Os tratamentos constaram de três fontes de K (KCl, rocha alcalina e fonolito moído, com 58%, 11% e 8.42% de K2O, respectivamente) aplicados em quatro doses (0, 25, 50 e 100 kg K2O ha-1). As doses de potássio foram aplicadas na soja e seu efeito residual foi avaliado na cultura do trigo, cultivado em sucessão. Logo após a colheita, as sementes de soja e trigo foram avaliadas pelos testes de teor de água, massa de sementes, germinação, primeira contagem, condutividade elétrica, comprimento de plântulas e massa da matéria seca de plântulas. Plantas de soja adubadas com fontes alternativas para fornecimento de K produzem sementes com maior massa e menor permeabilidade de membranas comparado às com KCl; maior qualidade fisiológica de sementes de soja e massa de sementes de trigo são obtidas com maiores doses de K2O independente da fonte.
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The simultaneous existence of alternative oxidases and uncoupling proteins in plants has raised the question as to why plants need two energy-dissipating systems with apparently similar physiological functions. A probably complete plant uncoupling protein gene family is described and the expression profiles of this family compared with the multigene family of alternative oxidases in Arabidopsis thaliana and sugarcane (Saccharum sp.) employed as dicot and monocot models, respectively. In total, six uncoupling protein genes, AtPUMP1-6, were recognized within the Arabidopsis genome and five (SsPUMP1-5) in a sugarcane EST database. The recombinant AtPUMP5 protein displayed similar biochemical properties as AtPUMP1. Sugarcane possessed four Arabidopsis AOx1-type orthologues (SsAOx1a-1d); no sugarcane orthologue corresponding to Arabidopsis AOx2-type genes was identified. Phylogenetic and expression analyses suggested that AtAOx1d does not belong to the AOx1-type family but forms a new (AOx3-type) family. Tissue-enriched expression profiling revealed that uncoupling protein genes were expressed more ubiquitously than the alternative oxidase genes. Distinct expression patterns among gene family members were observed between monocots and dicots and during chilling stress. These findings suggest that the members of each energy-dissipating system are subject to different cell or tissue/organ transcriptional regulation. As a result, plants may respond more flexibly to adverse biotic and abiotic conditions, in which oxidative stress is involved. © The Author [2006]. Published by Oxford University Press [on behalf of the Society for Experimental Biology]. All rights reserved.
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Based on the hypothesis that alternative substrates should improve the yield of lettuce crops by producing better quality seedlings, the objective of this work was to evaluate the effect of different substrates on the production of seedlings of this species, and their growth in the field. The study was in two stages. The first consisted of the production of lettuce seedlings, and the second assessed their development in the field. Four alternative substrates were tested, obtained by mixing together a sieved vermicompost from which all clumps had been removed, sterilized sand, charred rice husks and basalt powder. The commercial substrate, Plantmax HA®, was also tested. In the first phase, which was conducted in a completely randomised design with four replications, the height, root length, number of leaves, leaf area and dry weight of the seedlings were all evaluated 28 days after sowing. In the second phase, which was carried out in the field in a randomised block design with four replications, the plants were harvested 50 days after transplanting and the head diameter, fresh weight, number of leaves and leaf and stem dry weight were evaluated. The alternative substrates produced larger seedlings in less time than the commercial substrate, resulting in a reduction of 10 days in the total crop cycle. The reduction in the time between sowing and harvesting, together with those aspects relating to sustainability, are the main advantages of the use of alternative substrates, since in the field crop production did not differ between treatments.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)