LAMINAR FORCED CONVECTION IN HORIZONTAL CHANNEL WITH HEAT GENERATION PLATES COOLED BY WATER

This paper describes the study of the behavior of two-dimensional and parallel horizontal flat plates with uniform internal heat generation subjected to laminar forced convection of water. The governing equations are solved numerically using the finite volume technique with Power-Law interpolating scheme and the SIMPLE algorithm. After the simulations the temperature and velocity fields were obtained for various plates spacing and fluid inlet velocities, as well as the Nusselt number values

Avaliação do efeito de plantas inseticidas e produtos comerciais sobre folhas de mandioca (Manihot esculenta Crantz).

A mandioca Manihot esculenta Crantz é uma planta rica em carboidratos de grande importância socioeconômica para os estados que a produzem. Cultivada em todo o Brasil devido a sua adaptação às diversas condições edafoclimáticas, no nordeste se destaca por ser utilizada no combate à fome (LIMA, et al. 2012). Durante o ciclo produtivo é atacada por diversos insetos pragas e a utilização de pesticidas encarece a produção e provoca danos ao meio ambiente. Nesse contexto, as plantas inseticidas ressurgem como alternativa para minimizar os impactos provocados pelos agrotóxicos (CARBALI, et al, 2009). Dentre as plantas utilizadas no controle de insetos pragas, tem-se o Chenopodium ambrosioides L. em lepidópteros e coleópteros, o Zingiber officinale Roscoe em afídeos e o Azadirachta indica A. de Jussie que figura-se como a mais importante, devido a sua ação de mortalidade, repelência, fagoinibidor, ainda atua sobre o desenvolvimento de fase jovem dos insetos além de ser seletivo à inimigos naturais (CORRÊA; SALGADO, 2011). No Entanto as plantas inseticidas também apresentam desvantagens, sendo que a fitotoxicidade é pouco estudada (XUAN, et al., 2004). De acordo com Karlsson (2005), a fitotoxicidade é definida como a capacidade de um produto provocar danos temporários ou permanentes a uma planta. As partes mais afetadas pelos extratos de plantas inseticidas são as folhas, causando nas mesmas, necrose no limbo foliar, engruvilhamento, descoloração e redução do tamanho com efeito direto na capacidade de realizar fotossíntese. Dessa forma, o objetivo deste trabalho foi avaliar o efeito de plantas inseticidas Azadirachta indica, Zingiber officinale e Chenopodium ambrosioides e produtos comerciais Azamax® e Organic Neem® sobre folhas de mandiocas Manihot esculenta Crantz

A nonextensive insight to the stellar initial mass function

the present paper, we propose that the stellar initial mass distributions as known as IMF are best fitted by $q$-Weibulls that emerge within nonextensive statistical mechanics. As a result, we show that the Salpeter's slope of $\sim$2.35 is replaced when a $q$-Weibull distribution is used. Our results point out that the nonextensive entropic index $q$ represents a new approach for understanding the process of the star-forming and evolution of massive stars.Comment: 5 pages, 2 figures, Accepted to EP

Bioenergy potential of hydrocarbonoclastic bacteria fattened-up from industrial wastewaters

Microbial lipids are currently of great interest as raw material for biofuels production. Hydrocarbonoclastic bacteria (HCB), key players in bioremediation of hydrocarbon contaminated ecosystems, can produce and accumulate up to 90 % of its weight in lipids when submitted to growth-limiting conditions (e.g. nitrogen limitation). The intensive usage of crude oil derivatives as lubricants, which corresponds to about 1% of the world’s total mineral oil consumption, originates equivalent volumes of wastes. This lubricant wastes (LW) contains hydrocarbons ranging from C9 to C40, which can serve as substrate for HCB. Cultivation of HCB strains either in pure cultures or consortia with this type of industrial wastewater can, under optimized conditions, lead to production and accumulation of microbiological lipids, such as triglycerides (TAG). Combining TAG production with industrial wastewater treatment can contribute to make the process more economic and environmentally sustainable. This research aims at characterizing the potential of production and accumulation of bacterial lipids using 3. A concentrated wastewater collected from an engine’s repairing workshop, scarce in nitrogen and rich in HC, was fed (1.2% v/v) as sole carbon source, to representative HCB bacterial strains. Three different carbon to nitrogen molar ratios (C/N) were tested. After cultivation in nutrients balanced medium, the cells were washed and cultivated in a defined medium with excess of carbon. Different time lengths were evaluated for cultivation in nutrient balanced medium and under unbalanced conditions. For each condition tested, cells were harvested, freeze-dried, and its lipidic content was extracted and analyzed qualitatively. The profile of HC present in the culture media was 4. For Gram-negative HCB strain, the balanced growth conditions matched the period where the most significant HC removal was achieved. By the end of the exponential growth stage the chromatogram´s unresolved area decrease substantially and a 30% decrease in the concentration of compounds as tricosane and tetracosane was observed. The presence of TAG was detected in cells cultivated in unbalanced conditions. Fatty acids (FA) were detected in both conditions tested. The length of the accumulation period also showed to be an important factor in the experiments made with Gram-positive HCB strain. The late exponential or early stationary growth stages showed to be the most adequate period to transfer the biomass from balanced to unbalanced culture conditions. In general, the Gram-positive HCB strain showed a higher capacity to produce TAG from the tested wastewater. 5. The results obtained in our work show the potential of using hydrocarbon-based wastewaters to produce bacterial lipids. Further research is needed to determine the conditions that allow maximal storage lipid biosynthesis

Seed production of temperate forage legumes in Southern Brazil.

The objective of this interaction is to identify and prioritize the limiting factors, and overcome them with existing technologies or generating new knowledge through applied research