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Desenvolveu-se um sistema de alimentação misto para motores de ignição por compressão turboalimentados, o qual utiliza diesel injetado normalmente na câmara de combustão e etanol pós-vaporizado, injetado líquido no coletor de admissão e vaporizado pela grande disponibilidade de energia contida no ar comprimido. Foram possíveis substituições de até 55% da massa de diesel por etanol; funcionamento regular e repetitivo foi verificado, resultado da admissão de álcool na forma de vapor. Constatou-se que o rendimento térmico e as emissões de gases poluentes eram bastante influenciados pelo sistema de alimentação desenvolvido: ganhos de até 25,6% no rendimento térmico foram possíveis com reduções máximas de 81% na emissão de material particulado e 80% em NOx, pela queima mais eficiente do diesel na presença do vapor de etanol. Reduções notáveis na temperatura do ar comprimido foram atingidas, possibilitando a substituição dos \"intercoolers\". A análise teórica da implantação do sistema desenvolvido, numa frota de veículos de transporte coletivo da região metropolitana de São Paulo, indicou viabilidade econômica e ambiental. / It was developed a supplementary fueling system for turbocharged compression ignition, which uses diesel injected usually in the combustion chamber and post-vaporized ethanol, that is injected in the liquid state inside the intake manifold and vaporized by the energy in the compressed air. It was possible to replace up to 55% of the diesel mass by ethanol; regular and repetitive operation was verified, result of the alcohol induction in the vapor state. It was verified that engine\'s efficiency and pollutant gases emissions were quite influenced by the fueling system developed: improvements of up to 25,6% in the efficiency were possible, with maximum reductions of 81% in particulate matter and 80% in NOx, as a result of a more efficient diesel oxidation in presence of ethanol vapor. Notable reductions in the compressed air temperature were reached, making possible the substitution of the \"intercoolers\". The theoretical analysis to implantation of the developed system, on vehicles of public transportation in the metropolitan area of São Paulo, indicated economical and environmental viability.

Desenvolveu-se um sistema de alimentação misto para motores de ignição por compressão turboalimentados, o qual utiliza diesel injetado normalmente na câmara de combustão e etanol pós-vaporizado, injetado líquido no coletor de admissão e vaporizado pela grande disponibilidade de energia contida no ar comprimido. Foram possíveis substituições de até 55% da massa de diesel por etanol; funcionamento regular e repetitivo foi verificado, resultado da admissão de álcool na forma de vapor. Constatou-se que o rendimento térmico e as emissões de gases poluentes eram bastante influenciados pelo sistema de alimentação desenvolvido: ganhos de até 25,6% no rendimento térmico foram possíveis com reduções máximas de 81% na emissão de material particulado e 80% em NOx, pela queima mais eficiente do diesel na presença do vapor de etanol. Reduções notáveis na temperatura do ar comprimido foram atingidas, possibilitando a substituição dos \"intercoolers\". A análise teórica da implantação do sistema desenvolvido, numa frota de veículos de transporte coletivo da região metropolitana de São Paulo, indicou viabilidade econômica e ambiental. / It was developed a supplementary fueling system for turbocharged compression ignition, which uses diesel injected usually in the combustion chamber and post-vaporized ethanol, that is injected in the liquid state inside the intake manifold and vaporized by the energy in the compressed air. It was possible to replace up to 55% of the diesel mass by ethanol; regular and repetitive operation was verified, result of the alcohol induction in the vapor state. It was verified that engine\'s efficiency and pollutant gases emissions were quite influenced by the fueling system developed: improvements of up to 25,6% in the efficiency were possible, with maximum reductions of 81% in particulate matter and 80% in NOx, as a result of a more efficient diesel oxidation in presence of ethanol vapor. Notable reductions in the compressed air temperature were reached, making possible the substitution of the \"intercoolers\". The theoretical analysis to implantation of the developed system, on vehicles of public transportation in the metropolitan area of São Paulo, indicated economical and environmental viability.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The maize weevil (Sitophilus zeamais) is one of the stored grain pests of major importance in the world. The indiscriminate use of conventional insecticides has led to the selection of populations of resistant S. zeamais. Although the essential oils (EO) of plants are considered an alternative to conventional insecticides, their range of use due to insect populations with different capacities resistance has not been determined. We examined the toxicity of the EO of Pogostemon cablin and its nanoemulsion on nine populations of S. zeamais from different regions of Brazil. For that were performed bioassays topical application, contact, fumigation, and repellency effects on population growth. Fifteen compounds were identified the EO of P. cablin, and patchoulol was major component (55.04%). The EO of P. cablin showed average activity against the nine populations of S. zeamais when applied topically. The time required to cause 50% mortality of the population was 33.4 hours. The nine populations of S. zeamais responded similarly to EO of P. cablin. The lethal dose to kill 50% of the population resulted in low toxicity index (<2). The population of Viçosa-MG was more susceptible the EO of P. cablin, with LD50 of 9.17 and 8.01 μg mg-1 after 48 and 72 hours exposure respectively. The greater tolerance of EO P. cablin was detected in the population of Sete Lagoas, Minas Gerais, which increased the LD50 of 1.77 and 1.53 times. The concentration the EO of P. cablin required to cause 50% mortality of the population by contact and fumigation ranged from 0.34 to 0.43 μl ml-1 and from 28.6 to 33.5 μl l-1, respectively. Already the nanoemulsion P. cablin showed LC50 ranging from 1.28 to 8.84 μl ml-1 and from 32.7 to 39.5 μl l-1. There was an increase in toxicity by contact and fumigation (LC50) of the nanoemulsion of P. cablin from 48 to 72 hours of exposure. Toxicity (LC50) for contact and fumigation on populations of Viçosa-MG and Sete Lagoas-MG after 48 and 72 hours of exposure to EO P. cablin was in most cases greater than the toxicity caused by nanoemulsion of P. cablin. The EO and the nanoemulsion of P. cablin were LC50 and LC70 repellents in at all times of exposure for the population of Viçosa-MG. The same occurred with the population of Sete Lagoas, Minas Gerais, except for LC50 after 4, 6 and 8 hours of exposure and the LC70 after 24 hours of exposure to nanoemulsion of P. cablin. For the population of Viçosa-MG, there was no difference in repellency caused by EO and nanoemulsion of P. cablin. As for the population of Sete Lagoas, Minas Gerais, EO P. cablin caused greater repellency to this population compared to this oil nanoemulsion. Increasing concentrations of nanoemulsion of P. cablin resulted in reduction and consumption of grains of the two populations. Populations of Viçosa-MG and Sete Lagoas-MG entered decline (ri <0) using concentrations of 50.15 and 67.29 μl kg-1, respectively. / O gorgulho do milho (Sitophilus zeamais) e uma das pragas de graos armazenados de maior importancia no mundo. O uso indiscriminado de inseticidas convencionais tem levado a selecao de populacoes de S. zeamais resistentes. Apesar dos oleos essenciais (OE) de plantas serem considerados uma alternativa ao uso de inseticidas convencionais, sua amplitude de utilizacao frente as populacoes de insetos com capacidades distintas de resistencia ainda nao foi determinada. Neste trabalho analisamos a toxicidade do OE de Pogostemon cablin e da nanoemulsao a base desse OE sobre nove populacoes de S. zeamais provenientes de diferentes regioes do Brasil. Para isso foram realizados bioensaios de aplicacao topica, contato, fumigacao, repelencia e efeitos sobre o crescimento populacional. Foram identificados quinze compostos no OE de P. cablin, sendo o patchoulol o componente majoritario (55,04%). O OE de P. cablin demonstrou atividade inseticida sobre as nove populacoes de S. zeamais quando aplicado topicamente. O tempo necessario para causar 50% de mortalidade das populacoes foi em media 33,4 horas. As nove populacoes de S. zeamais responderam de modo semelhante ao OE de P. cablin. As doses letais para matar 50% das populacoes resultaram em baixas razoes de toxicidade (<2). A populacao de Vicosa-MG foi a mais susceptivel ao OE de P. cablin, com DL50 de 9,17 e 8,01 Êg mg-1 apos 48 e 72 horas de exposicao, respectivamente. A maior tolerancia ao OE de P. cablin foi detectada na populacao de Sete Lagoas-MG, que apresentou aumento na DL50 de 1,77 e 1,53 vezes. A concentracao do OE de P. cablin necessaria para causar 50% de mortalidade das populacoes por contato e fumigacao variou de 0,34 a 0,43 Êl ml-1 e 28,6 a 33,5 Êl l-1, respectivamente. Ja a nanoemulsao de P. cablin apresentou CL50 que variaram de 1,28 a 8,84 Êl ml-1 e 32,7 a 39,5 Êl l-1. Houve aumento da toxicidade por contato e fumigacao (CL50) da nanoemulsao de P. cablin de 48 para 72 horas de exposicao. A toxicidade (CL50) por contato e fumigacao sobre as populacoes de Vicosa-MG e Sete Lagoas-MG apos 48 e 72 horas de exposicao ao OE de P. cablin foi, na maioria das vezes, maior do que a toxicidade causada pela nanoemulsao de P. cablin. O OE e a nanoemulsao de P. cablin foram repelentes nas CL50 e CL70 em todos os tempos de exposicao para a populacao de Vicosa-MG. O mesmo ocorreu com a populacao de Sete Lagoas-MG, excecao para a CL50 apos 4, 6 e 8 horas de exposicao e para a CL70 apos 24 horas de exposicao a nanoemulsao de P. cablin. Para a populacao de Vicosa-MG, nao houve diferenca na repelencia causada pelo OE e nanoemulsao de P. cablin. Ja para a populacao de Sete Lagoas-MG, o OE de P. cablin causou maior repelencia a esta populacao se comparado a nanoemulsao deste OE. Concentracoes crescentes da nanoemulsao de P. cablin resultaram em reducao do ri e do consumo de graos das duas populacoes. As populacoes de Vicosa-MG e Sete Lagoas-MG entraram em declinio (ri<0) a partir das concentracoes de 50,15 e 67,29 Êl kg-1, respectivamente.

Methyl bromide (MBr) was widely used as a soil fumigant to manage soilborne pests in plasticulture vegetable production; however, it has been banned by the United Nations Environment Programme. Alternatives to MBr must be implemented to sustain fresh market tomato productivity. Possible MBr alternatives include new fumigant compounds, improved plastic mulch, and grafting. Methyl iodide (MeI) and dimethyl disulfide (DMDS) were tested as fumigant alternatives to MBr for the control of yellow nutsedge and soilborne pathogens of tomato. Virtually impermeable film (VIF) and totally impermeable film (TIF) were tested for fumigant retention and yellow nutsedge control in tomato. Grafting onto resistant rootstocks was tested for bacterial wilt and nematode management in tomato. In the absence of a soil fumigant, TIF suppressed yellow nutsedge better than VIF. TIF increased fumigant retention compared to VIF at similar application rates. Reduced fumigant application rates could be used in combination with TIF while maintaining fumigant concentrations, weed control, and crop yields comparable to greater use rates with VIF. Shank applied DMDS rates could be lowered to 281 L/ha under TIF from 468 L/ha under VIF; shank applied MeI application rates could be reduced to 56 L/ha under TIF compared to 93 L/ha under VIF and drip applied DMDS could be reduced from 561 L/ha under VIF film to 374 L/ha under TIF. Grafting susceptible commercial tomato cultivars onto resistant tomato hybrid rootstocks increased yields and plant survival in bacterial wilt infested fields. "Cheong Gang", "BHN 998", and "BHN 1054" were the best performing rootstocks for bacterial wilt resistance and tomato fruit yield in severely infested fields. Grafting increased tomato yield and decreased root galling from root-knot nematodes in an infested field. Hybrid rootstock "RST 106" resulted in the lowest root-knot nematode galling. In conclusion, TIF with reduced rates of DMDS or MeI is a viable MBr alternative for fresh market tomato production to retain effective doses of fumigant, manage yellow nutsedge and maintain yields. Grafting is an effective MBr alternative to manage bacterial wilt and root-knot nematode and maintain tomato yields. / Ph. D.

This Project identified the relationships between storage conditions, dry matter losses (DMLs) caused by Fusarium species in cereal grains and mycotoxin contamination and assessed novel control strategies for post-harvest grain management including chemical control and ozone. F. graminearum, F. verticillioides and F. langsethiae were inoculated on wheat, maize and oats and stored under environmental conditions where marginal to optimum spoilage and mycotoxin contamination can occur. DMLs were calculated from the CO2 produced and were significantly correlated with deoxynivalenol (DON), zearalenone (ZEA), fumonisins (FUMs) and T-2 and HT-2 toxins respectively. Mycotoxin levels in wheat and maize exceeded the EU legislative limits with 0.9-1% DMLs. Therefore, CO2 monitoring during storage can indicate the level of contamination in a stored batch. Using CO2 production data at different water activity (aw) and temperature conditions, the environmental regimes at which F. langsethiae can grow and contaminate oats with T-2 and HT-2 toxins were identified for the first time. Five acids were examined in vitro and little effect was observed on Fusarium growth, in the aqueous form, while the effect on mycotoxin production varied. Dissolved in ethanol, adipic, fumaric and ferulic acids inhibited fungal growth and controlled DON and FUMs, but T-2 toxin was stimulated by the ethanol. Two garlic essential oils, propyl-propylthiosulfinate (PTS) and propyl propylthiosulfonate (PTSO) were studied for the first time. In vitro, 200 ppm reduced fungal growth (50-100%) and mycotoxin production by >90%. The efficacy was species-dependent. In naturally contaminated oats of 0.93 aw stored for 20 days, 16 ppm PTSO reduced T-2 and HT-2 toxins by 66% and ochratoxin A (OTA) by 88%, while 200 ppm PTS reduced OTA by 95%. In wheat, 100 ppm PTS reduced DON and ZEA and 300 ppm PTS reduced fumonisins by 40-80%. PTSO:PTS (1:1) at 400 and 600 ppm was very effective against DON and ZEA in wheat of 0.92 aw. Ozone (O3) exposure at 200 ppm for 30 min delayed Fusarium spore germination on media of 0.98 aw and inhibited germination at 0.94 aw. O3 was more effective against fungal spores than mycelium and little effect was observed on growing cultures. In vitro, mycotoxin production after exposure depended on the stage of life of the fungi. O3 reduced fungal populations in grains. Mycotoxin production in wet grains treated with 100-200 ppm O3 for 60 min and stored for up to 30 days was reduced or completely inhibited, depending on the species and the exposure system. Simultaneous drying of the grain due to the O3 passage was observed.