Molecular mass distribution of dextran in Brazilian sugar and insoluble deposits of cachaca

The dextran molecular mass distribution profile in 77 sugar samples from Brazil and twelve insoluble deposits (alcoholic flocks) samples from sugared cachacas (Brazilian sugar cane spirit) is described in terms of number-average molecular mass M,,, weight-average molecular mass M(w), Z-average molecular mass M,, and polydispersity. The analyses were performed by size-exclusion chromatography, using a refractive index detector. In most of the sugar samples, it was possible to identify two major groups of dextrans with Mw averages of 5 x 10(6) and 5 x 10(4) Da. Based on the evaluated parameters, the dextran distribution profile is about the same in samples analyzed over five seasons, and, therefore, it is likely that the Brazilian product pattern will not change very much over the years. In insoluble deposits from sugared cachacas, dextrans with Mw values in the order of the 10(5) Da were the most frequent ones, being present in 58% of the samples. (c) 2008 Elsevier Ltd. All rights reserved.

Banco de sementes de plantas daninhas e sua correlação com a flora estabelecida no agroecossistema cana-crua

O conhecimento da composição específica do banco de sementes de plantas daninhas e a sua correlação com a flora estabelecida são importantes para nortear o manejo a ser adotado e a escolha dos herbicidas. A colheita mecanizada de cana-de-açúcar acarretou mudanças significativas na composição da flora infestante, quando proporcionou a manutenção de uma camada de palha, reduziu a movimentação do solo e dispensou a prática da queimada. Foram realizados levantamentos do banco de sementes e da flora de plantas daninhas que se estabeleceu em 28 talhões colhidos mecanicamente, sem queima prévia da palha. Com base nos dados de banco de sementes, efetuaram-se estudos fitossociológicos e de correlação entre a composição do banco de sementes e a flora emergida. As principais espécies presentes no banco de sementes foram as pertencentes à classe das dicotiledôneas anuais, com destaque para Amaranthus spp. e diversas espécies de Euphorbiaceae e Convolvulaceae. As sementes de gramíneas tradicionais da cultura tiveram pouca participação. O banco de sementes apresentou correlação não-significativa com a flora emergente, independentemente da época de colheita do talhão, da metodologia de quantificação do banco de sementes e das espécies de plantas daninhas.

Sewage sludge as nitrogen and phosphorus source for cane-plant and first ratoon crops

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

S-metolachlor efficacy on the control of Brachiaria decumbens, Digitaria horizontalis, and Panicum maximum in mechanically green harvested sugarcane

Objetivou-se com este trabalho avaliar o controle em pré-emergência de Brachiaria decumbens, Digitaria horizontalis e Panicum maximum pelo herbicida S-metolachlor aplicado em pré-emergência em área de cana-de-açúcar colhida mecanicamente sem queima prévia das plantas, com e sem palha sobre o solo. O delineamento experimental foi o de blocos ao acaso, com quatro repetições, em esquema de parcela subdividida 7 x 2. Nas parcelas, foram estudados cinco tratamentos de herbicidas (S-metolachlor a 1,44, 1,92 e 2,40 kg ha-1; clomazone a 1,20 kg ha-1; e isoxaflutole a 0,188 kg ha-1) e duas testemunhas sem aplicação. Nas subparcelas, foi avaliada a manutenção ou não da palha de cana na superfície do solo. A eficácia do herbicida S-metolachlor não foi prejudicada pela presença de 14 ou 20 t ha-1 de palha de cana sobre o solo. Com a manutenção da palha, a dosagem de S-metolachlor para o controle adequado das plantas daninhas foi de 1,44kgha-1. No ambiente sem palha, o S-metolachlor controlou B. decumbens, D. horizontalis e P. maximum nas dosagens de 1.92, 1.44 e 1.92kgha-1, respectivamente. Nas duas condições de palha, os herbicidas clomazone e isoxaflutole foram eficazes para as espécies estudadas. O S-metolachlor não causou nenhum sintoma visível de intoxicação à cana-de-açúcar. O clomazone e o isoxaflutole ocasionaram injúrias visuais às plantas de cana. Os herbicidas estudados não afetaram o número de colmos viáveis por m², a altura e o diâmetro de colmos.

Manejo de convolvuláceas em dois cultivares de soja semeada diretamente sob palha residual de cana crua

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Queima e aditivos químicos e bacterianos na ensilagem de cana-de-açúcar

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Avaliação da queima e da adição de milho desintegrado com palha e sabugo na ensilagem de cana-de-açúcar

Neste trabalho, avaliou-se a fermentação da cana-de-açúcar queimada, ensilada com ou sem uso de aditivo seco. Os tratamentos (seis no total) consistiram da silagem de cana crua ou queimada, adicionada de 0, 50 ou 100 g/kg de milho desintegrado com palha e sabugo (MDPS), com base no peso verde da forragem. Foram determinados os teores de MS, PB, nitrogênio insolúvel em detergente ácido (NIDA), FDN, FDA, celulose, hemicelulose e lignina. Na avaliação das características fermentativas, foram determinados os valores de carboidratos solúveis, o poder tamponante, o pH e as concentrações de nitrogênio amoniacal e etanol. Como características microbiológicas, avaliou-se o desenvolvimento de leveduras. A inclusão de MDPS elevou os teores de MS e reduziu discretamente os teores de N-NH3 e etanol das silagens, não ocasionando efeito nos valores de pH e na população de leveduras. A presença do fogo reduziu a concentração de MS das silagens, elevou os teores de etanol e leveduras e diminuiu os teores de N-NH3. A fermentação etanólica durante a ensilagem não foi controlada com a inclusão de aditivo seco ou com o uso do fogo.

Modelagem matemática para o aproveitamento da biomassa residual de colheita da cana-de-açúcar com menor custo

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Analysis of the performance of an extraction-condensation steam turbine on a cogeneration system of a Brazilian sugar-alcohol factory

In this work a detailed thermodynamic analysis for an extraction-condensation steam turbine capable to drive a 40 MVA electricity generator in a sugar-alcohol factory was carried out. The use of this turbine in the cogeneration system showed that its efficiency contributed to increase the power generation, although the condensation reduces the overall efficiency of the plant. Sensibility analyses were performed to evaluate the behavior of the overall energy efficiency of a plant with the extraction-condensation turbine in function of the boiler efficiency, the specific consumption of steam in the processes and the condensation rate in the turbine. It was observed that the plant efficiency is very sensible to the condensation rate variation and it increases when there is an increase in the demand of steam for processes.

Elementos traço em material particulado atmosférico de uma região agroindustrial do sudeste do Brasil

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

NEW YEAST STRAINS FOR ALCOHOLIC FERMENTATION AT HIGHER SUGAR CONCENTRATION

New yeast strains for alcoholic fermentation were isolated from samples collected from Brazilian alcohol factories at the end of the sugar cane crop season. They were selected by their capacity of fermenting concentrated sugar cane syrup as well as high sucrose concentrations in synthetic medium with a conversion efficiency of 89-92%. The strains were identified as Saccharomyces cerevisiae.

Global and diffuse solar irradiances in urban and rural areas in southeast Brazil

The seasonal evolution of daily and hourly values of global and diffuse solar radiation at the surface are compared for the cities of São Paulo and Botucatu, both located in Southeast Brazil and representative of urban and rural areas, respectively. The comparisons are based on measurements of global and diffuse solar irradiance carried out at the surface during a six year simultaneous period in these two cities. Despite the similar latitude and altitude, the seasonal evolution of daily values indicate that São Paulo receives, during clear sky days, 7.8% less global irradiance in August and 5.1% less in June than Botucatu. on the other hand, São Paulo receives, during clear sky days, 3.6% more diffuse irradiance in August and 15.6% more in June than Botucatu. The seasonal variation of the diurnal cycle confirms these differences and indicates that they are more pronounced during the afternoon. The regional differences are related to the distance from the Atlantic Ocean, systematic penetration of the sea breeze and daytime evolution of the particulate matter in São Paulo. An important mechanism controlling the spatial distribution of solar radiation, on a regional scale, is the sea breeze penetration in São Paulo, bringing moisture and maritime aerosol that in turn further increases the solar radiation scattering due to pollution and further reduces the intensity of the direct component of solar radiation at the surface. Surprisingly, under clear sky conditions the atmospheric attenuation of solar radiation in Botucatu during winter - the biomass burning period due to the sugar cane harvest - is equivalent to that at São Paulo City, indicating that the contamination during sugar cane harvest in Southeast Brazil has a large impact in the solar radiation field at the surface.

Environmental evaluation of cogeneration scenarios in sugar industry

The development of new techniques that allow the analysis and optimization of energy systems bearing in mind environmental issues is indispensable in a world with finite natural resources and growing demand of energy. Among the energy systems that deserve special attention, cogeneration in the sugar industry must be pointed out, because it uses efficiently a common fuel for generation of useful heat and power. Within this frame, thermoeconomical optimization - 2nd Law of Thermodynamics analysis by exergy function and economic evaluation of the thermal system - gradually is taking importance as a powerful tool to assist to the decision making process. Also, the explicit consideration of environmental issues offers a better way to explore trade-offs between different aspects to support the decisions that must be made. In this work it is used the technique of Life Cycle Analysis (LCA) which allows to consider environmental matters as an integral part of the problem, in opposite to most of the environmental approaches that only reduce residuals generation , without taking into account impacts associated to other related processes. On the other hand, the consideration of environmental issues in optimization of energy systems is a novel and promissory contribution in the state of the art of energy optimization and LCA. The system under study is a sugar plant of Tucumán (Argentina) given the particular importance that this industry had inside the regional economy of the Argentinean Northwest. Although cogeneration comes being used a while ago in sugar industry, being the main objective the generation of heat and as secondary objective the electric power generation and mechanic power to cover several needs of working machineries, to the date it is no available a versatile tool that allows to analyze economical feasible alternatives bearing in mind environmental issues. At sugar plants, steam is generated in boilers using as fuel bagasse - cellulosic fiber waste obtained crushing the sugar cane- and it is used to give useful heat and shaft work to the plant, but it can also be used to generate electricity with export opportunities to the electrical network. The great number of process alternatives outlines a serious decision making problem in order to take advantage of the resources. Although the problem turns out to be a mixed non-linear problem (MINLP), the main contribution of this work is the development of a hybrid strategy to evaluate cogeneration alternatives that combines optimization approaches with environmental indicators. This powerful tool for its versatility and robustness to analyze cogeneration systems, will be of great help in the decision making process, because of their easy implementation to analyze the kind of problems presented in the sugar industry.

Carbon dioxide emissions under different soil tillage systems in mechanically harvested sugarcane

Soil tillage and other methods of soil management may influence CO 2 emissions because they accelerate the mineralization of organic carbon in the soil. This study aimed to quantify the CO2 emissions under conventional tillage (CT), minimum tillage (MT) and reduced tillage (RT) during the renovation of sugarcane fields in southern Brazil. The experiment was performed on an Oxisol in the sugarcane-planting area with mechanical harvesting. An undisturbed or no-till (NT) plot was left as a control treatment. The CO2 emissions results indicated a significant interaction (p < 0.001) between tillage method and time after tillage. By quantifying the accumulated emissions over the 44 days after soil tillage, we observed that tillage-induced emissions were higher after the CT system than the RT and MT systems, reaching 350.09 g m-2 of CO2 in CT, and 51.7 and 5.5 g m-2 of CO2 in RT and MT respectively. The amount of C lost in the form of CO2 due to soil tillage practices was significant and comparable to the estimated value of potential annual C accumulation resulting from changes in the harvesting system in Brazil from burning of plant residues to the adoption of green cane harvesting. The CO 2 emissions in the CT system could respond to a loss of 80% of the potential soil C accumulated over one year as result of the adoption of mechanized sugarcane harvesting. Meanwhile, soil tillage during the renewal of the sugar plantation using RT and MT methods would result in low impact, with losses of 12% and 2% of the C that could potentially be accumulated during a one year period. © 2013 IOP Publishing Ltd.

Analysis of efficiency and rationality in a sugar-alcohol mill using hyperboloid a-load and potency

Brazil is the world's largest producer of sugar cane and which in the state of São Paulo concentrate the greatest amount of sugar cane field of the country. The sugar-alcohol sector has the capacity to produce sufficient thermal and electrical energy to be used in their process of production and commercialize of surplus in electricity distribution network. Therefore it is necessary to evaluate the energy efficiency and rationality within the mill. Accordingly this research proposed analyze the sugar-alcohol mill's sectors globally and individually, located in the west center of the São Paulo state, using the valuation methodology employed by the Agência Nacional de Energia Elétrica (ANEEL) in the industries that do not have systems of cogeneration. In this analysis, the hyperboloids of load and potency were applied based on the indexes of potency factor and load factor that allow estimate the efficiency and rationality. © 2013 IEEE.