NOX EMISSION ON RECIPROCAL FILTRATION COMBUSTION OF BIOGAS: A CASE STUDY

Filtration combustion is an effective technique for dealing with low-calorific value fuels, such as derivative fuels from biomass, and simultaneously reducing pollutant emissions. In this study, combustion of biogas (22% of CO2) was investigated theoretically and experimentally by utilizing a reciprocal flow porous burner with heat exchangers inserted in the porous medium. Combustion of lean biogas-air mixtures is stabilized in a naturally transient process, in which a lean equivalence ratio range (0.1 ≤ Φ ≤ 0.9) and gas flow velocities of 0.2 and 0.3 m/s were employed, periodically switching gas flow direction. Reciprocal flow combustion has been compared with unidirectional combustion, using technical methane as reference gas. In this context, predicted temperature profiles inside the burner, as well as experimental results, have shown that the reciprocating system plays an important role in the combustion process, significantly improving flammability limits, efficiency, and emissions. As result, trapezoidal temperature distribution profiles have been obtained with peaks between 1200 and 1600 K, reaching high efficiency up to 90% and ultra-low emission of nitrogen oxides (≤ 2ppm)

Avaliação qualitativa e quantitativa da microbiota do solo e da fixação biológica do nitrogênio pela soja.

O objetivo deste trabalho foi definir, para as condições edafoclimáticas do Brasil, níveis aceitáveis de dispersão de alguns parâmetros biológicos, utilizados em estudos de impacto ambiental de novas tecnologias usadas na cultura da soja. Dois ensaios com soja convencional e transgênica foram conduzidos em 11 municípios de seis estados e no Distrito Federal; os parâmetros avaliados foram: carbono e nitrogênio da biomassa microbiana, respiração basal e quociente metabólico microbiano, eletroforese do DNA do solo em géis desnaturantes (DGGE), fixação biológica do nitrogênio, população de rizóbios, número e massa de nódulos secos, ocupação dos nódulos pelas estirpes de Bradyrhizobium, massa de matéria seca da parte aérea, nitrogênio total e nitrogênio como ureídos na parte aérea. A variabilidade temporal de: carbono e nitrogênio, da biomassa microbiana, da respiração basal e do quociente metabólico microbiano foi adequada, e o coeficiente de variação máximo aceitável foi estimado em 35%. A homogeneidade entre repetições, tratamentos e coletas foi confirmada por DGGE. Em solos pobres em nitrogênio, os parâmetros de massa de nódulos e massa da parte aérea, com coeficiente de variação máximo de 33 e 18%, respectivamente, foram adequados para avaliar a fixação biológica do N, que contribuiu com 72 a 88% do nitrogênio total da parte aérea

Desenvolvimento e avaliação de uma semeadora adubadora à tração animal.

O presente trabalho constitui-se numa tentativa de melhorar a produtividade das culturas e, conseqüentemente, a renda de pequenos agricultores, em decorrência de uma melhor qualidade na operação de semeadura. Foi desenvolvido um protótipo de uma semeadora adubadora à tração animal. Este foi encaminhado a pequenos agricultores para avaliação, tendo sido refeito com base no resultado destas avaliações. O segundo protótipo foi avaliado em um ensaio realizado na área experimental da Escola de Agronomia e Engenharia de Alimentos da Universidade Federal de Goiás (Goiânia, Goiás). O equipamento apresentou desempenho técnico compatível com o de uma semeadora adubadora à tração animal. Verificou-se que esse pode oferecer aos pequenos e médios agricultores bons resultados na operação de semeadura. Em termos médios, a semeadora necessita de 697,4 N de força para ser tracionada, apresentando um rendimento operacional de 1,0 ha/h. Deposita as sementes a uma profundidade média de 34 mm, deixando cerca de 1,4 sementes descobertas por metro

Desenvolvimento e avaliação de um pulverizador de barras a tração humana.

O trabalho foi desenvolvido mediante convênio firmado entre a Escola de Agronomia e Engenharia de Alimentos - Universidade Federal de Goiás, a Empresa Brasileira de Pesquisa Agropecuária - Embrapa Arroz e Feijão e a Agência Goiana de Desenvolvimento Rural e Fundiário. Teve como objetivo o desenvolvimento e a avaliação de um protótipo de pulverizador de barras à tração humana, equipado com bicos hidráulicos. Determinaram-se as seguintes variáveis: capacidade de campo efetiva (ha.h-1), densidade de gotas de pulverização (gotas.cm-2) e quantidade de depósito de pulverização (ng.cm-2). O protótipo funcionou satisfatoriamente. Para a amostragem das pulverizações posterior avaliação da distribuição de gotas, empregaram-se alvos compostos de cartões de papel sensível à água e lâminas de microscópio, distribuídos sobre o solo. As avaliações foram realizadas em condições de solo recém preparado, em área de pastagem e em culturas de milho, feijão e arroz. Nos diferentes tratamentos empregados, o pulverizador apresentou uma capacidade de campo efetiva média de 1,18 ha.h-1, uma densidade média de gotas de 81,4 gotas.cm-2 e uma quantidade média de produto recuperado ao nível do solo de 64,8 ng.cm-2

Heterogeneity at the HLA-DRB1 locus and risk for multiple sclerosis.

Variation in major histocompatibility complex genes on chromosome 6p21.3, specifically the human leukocyte antigen HLA-DR2 or DRB1*1501-DQB1*0602 extended haplotype, confers risk for multiple sclerosis (MS). Previous studies of DRB1 variation and both MS susceptibility and phenotypic expression have lacked statistical power to detect modest genotypic influences, and have demonstrated conflicting results. Results derived from analyses of 1339 MS families indicate DRB1 variation influences MS susceptibility in a complex manner. DRB1*15 was strongly associated in families (P=7.8x10(-31)), and a dominant DRB1*15 dose effect was confirmed (OR=7.5, 95% CI=4.4-13.0, P<0.0001). A modest dose effect was also detected for DRB1*03; however, in contrast to DRB1*15, this risk was recessive (OR=1.8, 95% CI=1.1-2.9, P=0.03). Strong evidence for under-transmission of DRB1*14 (P=5.7x10(-6)) even after accounting for DRB1*15 (P=0.03) was present, confirming a protective effect. In addition, a high risk DRB1*15 genotype bearing DRB1*08 was identified (OR=7.7, 95% CI=4.1-14.4, P<0.0001), providing additional evidence for trans DRB1 allelic interactions in MS. Further, a significant DRB1*15 association observed in primary progressive MS families (P=0.0004), similar to relapsing-remitting MS families, suggests that DRB1-related mechanisms are contributing to both phenotypes. In contrast, results obtained from 2201 MS cases argue convincingly that DRB1*15 genotypes do not modulate age of onset, or significantly influence disease severity measured using expanded disease disability score and disease duration. These results contribute substantially to our understanding of the DRB1 locus and MS, and underscore the importance of using large sample sizes to detect modest genetic effects, particularly in studies of genotype-phenotype relationships

Comparative genomics of Bradyrhizobium japonicum CPAC 15 and Bradyrhizobium diazoefficiens CPAC 7: elite model strains for understanding symbiotic performance with soybean.

The soybean-Bradyrhizobium symbiosis can be highly efficient in fixing nitrogen, but few genomic sequences of elite inoculant strains are available. Here we contribute with information on the genomes of two commercial strains that are broadly applied to soybean crops in the tropics. B. japonicum CPAC 15 (=SEMIA 5079) is outstanding in its saprophytic capacity and competitiveness, whereas B. diazoefficiens CPAC 7 (=SEMIA 5080) is known for its high efficiency in fixing nitrogen. Both are well adapted to tropical soils. The genomes of CPAC 15 and CPAC 7 were compared to each other and also to those of B. japonicum USDA 6T and B. diazoefficiens USDA 110T. Differences in genome size were found between species, with B. japonicum having larger genomes than B. diazoefficiens. Although most of the four genomes were syntenic, genome rearrangements within and between species were observed, including events in the symbiosis island. In addition to the symbiotic region, several genomic islands were identified. Altogether, these features must confer high genomic plasticity that might explain adaptation and differences in symbiotic performance. It was not possible to attribute known functions to half of the predicted genes. About 10% of the genomes was composed of exclusive genes of each strain, but up to 98% of them were of unknown function or coded for mobile genetic elements. In CPAC 15, more genes were associated with secondary metabolites, nutrient transport, iron-acquisition and IAA metabolism, potentially correlated with higher saprophytic capacity and competitiveness than seen with CPAC 7. In CPAC 7, more genes were related to the metabolism of amino acids and hydrogen uptake, potentially correlated with higher efficiency of nitrogen fixation than seen with CPAC 15. Several differences and similarities detected between the two elite soybean-inoculant strains and between the two species of Bradyrhizobium provide new insights into adaptation to tropical soils, efficiency of N2 fixation, nodulation and competitiveness

Exploring hypotheses of the actions of TGF-beta 1 in epidermal wound healing using a 3D computational multiscale model of the human epidermis

In vivo and in vitro studies give a paradoxical picture of the actions of the key regulatory factor TGF-beta 1 in epidermal wound healing with it stimulating migration of keratinocytes but also inhibiting their proliferation. To try to reconcile these into an easily visualized 3D model of wound healing amenable for experimentation by cell biologists, a multiscale model of the formation of a 3D skin epithelium was established with TGF-beta 1 literature-derived rule sets and equations embedded within it. At the cellular level, an agent-based bottom-up model that focuses on individual interacting units ( keratinocytes) was used. This was based on literature-derived rules governing keratinocyte behavior and keratinocyte/ECM interactions. The selection of these rule sets is described in detail in this paper. The agent-based model was then linked with a subcellular model of TGF-beta 1 production and its action on keratinocytes simulated with a complex pathway simulator. This multiscale model can be run at a cellular level only or at a combined cellular/subcellular level. It was then initially challenged ( by wounding) to investigate the behavior of keratinocytes in wound healing at the cellular level. To investigate the possible actions of TGF-beta 1, several hypotheses were then explored by deliberately manipulating some of these rule sets at subcellular levels. This exercise readily eliminated some hypotheses and identified a sequence of spatial-temporal actions of TGF-beta 1 for normal successful wound healing in an easy-to-follow 3D model. We suggest this multiscale model offers a valuable, easy-to-visualize aid to our understanding of the actions of this key regulator in wound healing, and provides a model that can now be used to explore pathologies of wound healing