914 resultados para Rheological additives
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Avaliaram-se a digestibilidade ileal e a retenção de alguns nutrientes e os valores de energia de dietas contendo mananoligossacarídeo (MOS) e/ou complexo enzimático (CE) para frangos de corte. Foram utilizadas 275 aves em delineamento em blocos ao acaso e arranjo fatorial 2 x 2 + 1, com dois níveis de MOS (0 e 0,1%), dois níveis de complexo enzimático (0 e 0,05%) e uma dieta controle positivo com antibióticos. O óxido crômico (0,5%) foi adicionado às dietas para estimativa do fator de indigestibilidade. O experimento teve início quando as aves completaram 13 dias de idade; a coleta de excretas foi realizada do 20º ao 22º dia e a de digesta, no 23º dia de idade das aves. A interação MOS × CE foi significativa para a retenção de PB e P e de energia metabolizável aparente (EMA), cujos valores foram maiores nas dietas com MOS e CE. A inclusão do CE melhorou a retenção de MS e os coeficientes de digestibilidade ileal de MS, PB, Ca e P na retenção de cálcio e nos valores de energia digestível com a inclusão de mananoligossacarídeo. Os coeficientes de digestibilidade ileal da MS, a retenção de MS, PB, Ca e P e os valores de energia digestível e de EMA das dietas contendo MOS e/ou CE foram superiores aos obtidos com a dieta contendo antibióticos.
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Este trabalho foi conduzido com o objetivo de verificar o efeito da adição de antibiótico, probiótico, prebiótico e gluconato de sódio para suínos no período de 28 a 142 dias de idade, correspondente às fases de creche, crescimento e terminação. Foram utilizados 168 leitões desmamados aos 21 dias de idade, distribuídos em delineamento inteiramente casualizado em 42 baias com quatro suínos machos castrados em cada unidade experimental, com seis repetições e sete dietas: ração basal (controle negativo); ração basal + antibiótico; ração basal + probiótico; ração basal + prebiótico; ração basal + probiótico + prebiótico (simbiótico); ração basal + gluconato de sódio; ração basal + gluconato de sódio + probiótico. O desempenho dos animais diferiu entre as dietas e foi melhor nos animais que receberam ração com aditivos no período de 28 a 142 dias de idade. Entre os aditivos, o simbiótico foi mais eficiente, pois promoveu os melhores resultados de ganho de peso e conversão alimentar. do mesmo modo, a adição de gluconato de sódio + probiótico, prebiótico e probiótico nas rações foi mais eficiente que a adição de antibiótico. A utilização dos aditivos avaliados em substituição ao antibiótico não compromete as características de carcaça e a morfometria intestinal. A associação do probiótico e prebiótico (simbiótico) estudados melhora o desempenho dos suínos nas fases de creche, crescimento e terminação.
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Meaning fuel and renewal energy source s derivative additives, the term biodiesel exists in Brazil since 1980, when it was signed its first patent by Expedito Parente. Since then, its importance has grown gradually due to the worsening of the ambient problems, since its use has became a highly promising alternative to the pollution decrease, as in the carbon dioxide issue as with the smoke and sulfur oxide. In Brazil, it was created the National Program of Production, whose objective is to insert the new product in the country s energy matrix, strengthening the economy and creating new employment opportunities, being an important product to the national energetic independence, since Brazil still imports diesel to its domestic consumption. This study aims to identify the ambient, social and economic perception of the teachers from the Technology Center of Natal city (CTGÁS-RN) to the biodiesel. For that, it was used a questionnaire closed questions, organized in the likart scale, directed to the tree spheres of the research analysis, the biodiesel and its social, ambient and economic nuances, totaling 31 questionnaires full answered. In its objectives, the research was descriptive and in its approach it was qualitative. To the data analysis it was used statistical tools (Statistic software, 6.1 version and Microsoft Excel 2003). The research revealed the predominance of the ambient aspect in the sight of the teachers, followed by the social ones. The economic factors represent a minor percentage in the analysis when compared to other
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Foram estudados os efeitos da adição de 15% de diferentes aditivos - casca de café, farelo de cacau e farelo de mandioca - à forragem verde de capim-elefante (peso/peso), no momento da ensilagem, sobre a digestibilidade aparente de dietas. Foram usados 20 ovinos machos, não castrados, com média de 22,27±3,24kg de peso corporal, em um delineamento inteiramente ao acaso, com quatro tratamentos e cinco repetições. Os tratamentos foram: T1 = capim-elefante ensilado sem aditivo; T2 = capim-elefante ensilado com 15% de casca de café; T3 = capim-elefante ensilado com 15% de farelo de cacau; T4 = capim-elefante ensilado com 15% de farelo de mandioca. Os animais receberam dieta isoproteica (10% de proteína bruta) em proporção de 60% de volumoso e 40% de concentrado, na base da matéria seca. Utilizou-se o método de coleta total de fezes durante sete dias. Os coeficientes de digestibilidade aparente da matéria seca, proteína bruta, fibra em detergente neutro e fibra em detergente ácido e de digestibilidade verdadeira da proteína bruta foram maiores no capim-elefante ensilado sem aditivo. O coeficiente de digestibilidade do extrato etéreo foi mais alto na silagem sem aditivo e na silagem com farelo de cacau. Os coeficientes de digestibilidade da matéria orgânica e dos carboidratos totais foram mais elevados na silagem sem aditivo e na silagem com farelo de mandioca. Os maiores valores de nutrientes digestíveis totais foram observados nas dietas que continham silagem sem aditivo e silagem com farelo de mandioca. A silagem de capim-elefante com 15% de farelo de mandioca, bem como a silagem sem aditivo apresentaram melhor digestibilidade dos nutrientes.
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Foram estudados os efeitos da glutamina, dos ácidos graxos poli-insaturados e da parede celular de levedura (PCL) sobre a estrutura e ultraestrutura do intestino delgado e o desempenho de leitões. Foram utilizados 45 leitões, desmamados aos 21 dias de idade, para testar os seguintes tratamentos: T1 - dieta basal; T2 - dieta basal + 1% de glutamina; T3 - dieta basal + 0,2% de PCL; T4 - dieta basal + 5% de óleo de peixe. Nos dias sete e 14 pós-desmame, foram abatidos cinco leitões de cada tratamento. Os aditivos testados não alteraram a altura e a densidade dos vilos nem a profundidade das criptas do intestino delgado. Foi observado efeito de idade, mostrando redução na altura e na densidade dos vilos e na profundidade das criptas após o desmame. No duodeno e jejuno, foram observados maiores valores de relação vilo:cripta, que aumentaram com a idade pós-desmame. Ocorreram redução da altura dos microvilos do duodeno aos sete dias e aumento da largura dos microvilos do jejuno aos 14 dias pós-desmame. A área de superfície apical dos enterócitos não foi alterada pelos fatores estudados. Os aditivos estudados não foram eficientes em prevenir a atrofia da mucosa intestinal do jejuno, ao não interferir na sua ultraestrutura. Os aditivos incluídos na dieta não influenciaram o desempenho dos leitões no pós-desmame.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Com o objetivo de avaliar as perdas em silagem de capim-marandu produzidas com aditivos foram desenvolvidos dois experimentos. No experimento 1, objetivou-se conhecer o perfil de fermentação e a estabilidade aeróbia de quatro silagens: 1) forragem não tratada (Controle); 2) tratada com Lactobacillus plantarum e Propionibacterium; 3) tratada com Lactobacillus buchneri; e 4) tratada com 0,1% de benzoato de sódio. No experimento 2, foram utilizados nove novilhos castrados Nelore (PC de 350 ± 38,9 kg), alocados em três quadrados latinos 3 x 3 para avaliação do consumo e da digestibilidade das rações contendo 85,4% das seguintes silagens de capim-marandu: 1) controle; 2) controle com L. plantarum, Pediococcus acidilactici + enzimas fibrolíticas; e 3) tratamento 2 + L. buchneri. No experimento 1, as silagens apresentaram baixas recuperações de MS durante a fermentação (média de 86%) e os coeficientes de digestibilidade in vitro da matéria seca reduziram de 65,5% (momento da ensilagem) para 50,0% no 60º dia após o fechamento dos silos. No experimento 2, o valor médio de consumo das rações foi de 5,7 kg MS/dia (1,6% PC) e a digestibilidade de 51,6% e não diferiram entre as rações. As silagens apresentaram perdas acentuadas na fase fermentativa e o uso de aditivos não alterou essas perdas. A inoculação com bactérias não influenciou o consumo ou a digestibilidade das rações.
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Objetivou-se avaliar o efeito do uso de monensina, complexo de leveduras, ácidos graxos poliinsaturados e aminoácidos no consumo de matéria seca e nutrientes, na estimativa da digestibilidade ruminal, nos parâmetros de fermentação ruminal (pH, concentração de nitrogênio amoniacal e de ácidos graxos de cadeia curta), na população de protozoários e na produção de metano. Foram utilizados seis bovinos e com peso corporal de 530 ± 15 kg, recebendo complexo de leveduras, ácidos graxos poliinsaturados e aminoácidos (5 g/dia); monensina (5 g/dia); caulim (5 g/dia), usado como controle adicionado à dieta composta de feno de capim-tifton 85 (Cynodon spp.); e concentrado, na relação 80:20. O delineamento experimental adotado para análise do consumo e da digestibilidade foi o de blocos completos casualizados e, para análise dos parâmetros ruminais e da produção de metano, o de parcelas subdivididas. O consumo foi influenciado pelo uso de monensina na dieta, mas não diferiu entre os aditivos. As digestibilidades da matéria seca e dos nutrientes não foram influenciadas pelo fornecimento dos aditivos. A relação acetato:propionato nos animais alimentados com a dieta com monensina foi menor que naqueles que receberam o complexo de leveduras e ácidos graxos poliinsaturados e aminoácidos, diminuindo a perda de energia na forma de metano. O pH e a concentração de nitrogênio amoniacal foram adequados para o crescimento bacteriano. A concentração de metano não é alterada pelo uso dos aditivos testados.
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Broiler digestive tract fungal communities have gained far less scrutiny than that given corresponding bacterial communities. Attention given poultry-associated fungi have focused primarily on feed-associated toxin-producers, yeast, and yeast products. The current project focused on the use of pyrosequencing and denaturing gradient gel electrophoresis (DGGE) to identify and monitor broiler digestive fungal communities. Eight different treatments were included. Four controls were an Uninfected-Unmedicated Control, an Unmedicated-Infected Control, the antibiotic bacitracin methylene disalicylate plus the ionophore monensin as Positive Control, and the ionophore monensin alone as a Negative Control. Four treatments were two probiotics (BC-30 and Calsporin) and two specific essential oil blends (Crina Poultry Plus and Crina Poultry AF). All chickens except the Unmedicated-Uninfected Control were given, at 15 days of age, a standard oral Eimeria inoculum of sporulated oocysts. Ileal and cecal digesta were collected at pre-Eimeria infection at 14 days of age and at 7 days post-Eimeria infection at 22 days of age. Extracted cecal DNA was analyzed by pyrosequencing to examine the impact of diet supplements and Eimeria infection on individual constituents in the fungal community, while DGGE was used to compare more qualitative changes in ileal and cecal communities. Pyrosequencing identified three phyla, seven classes, eight orders, 13 families, 17 genera, and 23 fungal species. Ileal and cecal DGGE patterns showed fungal communities were clustered mainly into pre- and post-infection patterns. Post-infection Unmedicated-Uninfected patterns were clustered with pre-infection groups demonstrating a strong effect of Eimeria infection on digestive fungal populations. These combined techniques offered added versatility towards unraveling the effects of enteropathogen infection and performance enhancing feed additives on broiler digestive microflora.
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Composites with antimicrobial activity are of great interest nowadays and the development of titanium dioxide with these functional properties presents interest in academic and industrial sectors.An approach to develop PE composite containing silver microparticles to have an antimicrobial effect is presented. To obtain such antimicrobial composites, LDPE/EVA were processed with Ag particles on TiO2 particles as inorganic carrier substance. Titanium dioxide nanoparticles (P-25) were covered with silver particles using Turkevich Method or citrate reduction method. The Ag/TiO2 particles were dispersed at concentration of 0,8 wt% and 1% wt% in LDPE/ethylene vinyl acetate copolymer (EVA)-(50% w/w) at the melt state in a Haake torque Rheometer. Silver microparticles were characterized with UV-Vis Spectroscopy. The composites thus prepared were characterized through XRD, Ares Rheometer, Scanning Electronic Microscopy (SEM) and JIS Z 2801 antimicrobial tests to study the effects of the addition of particles on rheological properties, morphological behavior and antimicrobial properties. The results showed that incorporation of silver/titanium dioxide particles on composites obtained systems with differents dispersions. The Ag/TiO2 particles showed uniform distribution of Ag on TiO2 particles as observed by SEM-EDX and antimicrobial tests according to JIS Z 2801 shows excellent antimicrobial properties.
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The calcium phosphate ceramics have been very investigated as material for bone implants. The tricalcium phosphate (β-TCP) had a great potential for application in temporary implants like a resorbable bioceramic. This material presents a limitation in its sintering temperature due to occurrence of the allotropic transformation β → α at temperatures around 1200°C, not allowing the attainment of dense ceramic bodies. This transformation also causes cracks, what diminishes the mechanical strength, limiting its use to applications of low mechanical requests. This work studies the influence of the addition of manganese oxide in the sintering of β-TCP. Two processing routes were investigated. The first was the powder metallurgy conventional process. The test bodies (samples) were pressed and sintering at temperatures of 1200 and 1250°C. The second route was uniaxial hot pressing and its objective was to obtain samples with high relative density. The samples were physically characterized through density and porosity measurements. The thermal behavior was studied through dilatometric, thermal differential and thermogravimetric analysis. The mechanical properties were characterized by three point flexure test and Vickers microhardness measurements. The microstructure was analyzed by scanning electron microscopy. The addition of manganese oxide caused an improvement of the mechanical strength in relation to the material without additive and promoting the stabilization of β-TCP to greater temperatures
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The adhesive mortars are a mixture of cement, sand, and additives to polymers that retain the mixing water and promotes adherence, being used in setting on various ceramic substrates. The sand used in the production of these mortars is from the riverbeds, and with the increasing restriction of these sands extraction by environmental agencies, and often having to be transported over long distances to the consumer center. This work aims to design and physical and mechanical characterization of ecological adhesive mortar with total replacement of natural sand by sand from the crushing of limestone, and the addition of mineral ash biomass of cane sugar in partial replacement cement used in the production of adhesive mortar , aiming compositions that meet the regulatory specifications for use adhesive mortar. Standardized tests to determine the tensile bond strength (NBR 14081-4), determination of open time (NBR 14081-3) and determination of slip (NBR 14081-5) were performed. Were also conducted trials squeeze flow in different formulation, the mortar with addition of 15 % gray biomass of cane sugar for cement mortars as well as the total replacement of natural sand by sand limestone crushing, got the best performance among the mortars studied, it was found that the addition of biomass to replace cement is perfectly feasible due to its pozzolanic activity, which contributed to this reduction in the cement matrix formation of adhesive mortar
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The lubricants found in the market are of mineral or synthetic origin and harm to humans and the environment, mainly due to their improper discard. Therefore industries are seeking to develop products that cause less environmental impact, so to decrease mainly, operator aggression the Cutting Fluids became an emulsion of oil / water or water / oil. However, the emulsion was not considered the most suitable solution for environmental question, therefore the search for biodegradable lubricants and which no are toxic continues and so vegetable oils are seen, again, as a basis for the production of lubricants. The biggest problem with these oils is their oxidative instability that is intensified when working at high temperatures. The process transesterification decreases the oxidation, however changes some physical and chemical properties. Therefore soybean oil after the transesterification process was subjected to tests of density, dynamic viscosity, kinematic viscosity which is calculated from two parameters mentioned, flash point and acidity. Besides the physico-chemical test the soybean oil was subjected to a dynamic test in a tribometer adapted from a table vise, whose induced wear was the adhesive and ultimately was used as cutting fluid in a process of turning in two different materials, steel 1045 and cast iron. This latter test presented results below the mineral cutting fluid which it was compared in all tests, already in other experiments the result was satisfactory and other experiments not, so that chemical additives can be added to the oil analyzed to try equate all parameters and so formulate a biolubrificante not toxic to apply in machining processes of metalworking industry
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The determination of the rheology of drilling fluids is of fundamental importance to select the best composition and the best treatment to be applied in these fluids. This work presents a study of the rheological behavior of some addictives used as viscosifiers in water-based drilling fluids. The evaluated addictives were: Carboxymethylcellulose (CMC), Xanthan gum (GX), and Bentonite. The main objective was to rheologically characterize suspensions composed by these addictives, by applying mathematical models for fluid flow behavior, in order to determine the best flow equation to represent the system, as well as the model parameters. The mathematical models applied in this research were: the Bingham Model, the Ostwald de Wale Model, and the Herschel-Bulkley Model. A previous study of hydration time for each used addictive was accomplished seeking to evaluate the effect of polymer and clay hydration on rheological behavior of the fluid. The rheological characterization was made through typical rheology experiments, using a coaxial cylinder viscosimeter, where the flow curves and the thixotropic magnitude of each fluid was obtained. For each used addictive the rheological behavior as a function of temperature was also evaluated as well as fluid stability as a function of the concentration and kind of addictive used. After analyses of results, mixtures of polymer and clay were made seeking to evaluate the rheological modifications provided by the polymer incorporation in the water + bentonite system. The obtained results showed that the Ostwald de Waale model provided the best fit for fluids prepared using CMC and for fluids with Xanthan gum and Bentonite the best fit was given by the Herschel-Bulkley one