178 resultados para agitação


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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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The sol-gel process is a method for obtaining vitreous or vitro-ceramic materials which, are prepared a sol and by drying the liquid phase. This technique has been used extensively for the preparation of glassy gels, films, fibers and particles from the hydrolysis and polycondensation reactions of metal alkoxides. The usual methods for drying are: evaporation drying (xerogels), freeze drying (criogéis) and via supercritical CO2 extraction (aerogels). In the present work, we studied the preparation of silica gels by the sol-gel process from the hydrolysis of alkoxides tetraethylorthosilicate (TEOS) and 3-glycidoxypropyltrimethoxysilane (GPTS). The hydrolysis was promoted from GPTS and TEOS in proportion (4: 1) under acidic conditions. The hydrolysis reaction was promoted inside a Becker at room temperature. After hydrolyses the prepared sol had pH 2, and kept under mechanical agitation for a period of 1 hour. In order to accelerate the polycondensation reaction, the pH was corrected to a value near 5 by slowly adding NH4OH. Then the sols were leaked in sealed polycarbonate containers and maintained for 20 days at 40°C for gelation. Silica aerogels were prepared via supercritical CO2 extraction of the wet gel at temperature and pressure higher than 31°C and 74 atm, in an autoclave specially developed for the process. The structural characteristics were studied in the dry gel (aerogel). Aerogels were then characterized by nitrogen adsorption and small angle light scattering. The nitrogen adsorption data were analyzed for the determination of the BET specific surface (SBET), the total pore volume Vp, the pore mean size (lP=4Vp/SBET), the particle mean size (lS) and the pore size distribution (PSD). And the data from small angle light scattering were analyzed to determine the correlation function (γ'), the area per unit volume (S/V), average pore size (l ) and the average particle size...

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Na busca de novos recursos genéticos capazes de produzir enzimas celulolíticas a baixas/médias temperaturas, o continente Antártico vem demonstrando ser um ambiente bastante promissor. Neste contexto, o objetivo do presente trabalho foi avaliar a influência de diferentes fatores na produção de celulases por fungos filamentosos isolados de amostras da Antártica visando otimização do processo possível aplicação das mesmas na produção de etanol de segunda geração. Foram utilizados os fungos L1-1 e E5B da Central de Recursos Microbianos da UNESP (CRM-UNESP) os quais foram previamente selecionados devido ao potencial celulolítico. O delineamento experimental foi utilizado para analisar a influência de variáveis independentes na produção enzimática. A quantificação da celulase foi realizada pelo método do ácido dinitrosalicílico (ADNS). Antes de iniciar à aplicação dos planejamentos experimentais, foram adotadas estratégias para tentar minimizar e otimizar ao máximo o potencial dos isolados, as quais resultaram no estabelecimento da melhor agitação e a temperatura para a produção de celulase em 150 rpm e 20°C, para os dois isolados estudados. Inicialmente os fungos E5B e L1-1 apresentavam suas produções enzimáticas em 0,233U/mL e 0,342U/mL, respectivamente (antes da aplicação dos desenhos experimentais). Durante a condução do planejamento experimental do tipo Plackett&Burman(PB), foi verificada a preferência dos isolados pela fonte de carbono glicose, com efeito significativo na produção de celulases para os dois isolados. Tendo em vista o seu elevado custo comercial, foram realizados estudos com a sacarose, uma fonte de carbono alternativa e mais barata, bem como indutores enzimáticos. Após três planejamentos experimentais do tipo PB, foi selecionado o isolado L1-1 como o melhor produtor da enzima celulase. Após a condução de um quarto planejamento experimental do tipo Fatorial Fracionado 24-1, as...

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Persistent Organic Pollutants (POPs) are chemical substances extraordinarily toxic and persistent in the environment. Due to these properties, POPs are targets of the Stockholm Convention which aims to provide means to eliminate production and use by encouraging the reduction and, where possible, eliminating the release of these contaminants to the environment. One of the articles of this _Convention aims to assess the basal levels of such substances in the environment to monitor both the reduction of release to the environment, and to assess human exposure, using analyzes of milk and air for example. Although efforts to control POPs production and release to the environment have been made, data about their levels in Brazil are still scarce, mainly in the atmosphere or indoor environment. Considering the permanence of people inside its house, this study presents a method for POP extraction from XAD-2 sorbent employed in indoor air sampling, with identification and quantification by GC-ECD. GC-ECD linear range of the studied analytes, congeners of polychlorinated biphenyls (PCB) (28, 52, 101, 118, 138, 153 and 180), DDTs and their metabolites (DDDs, DDEs) and endosullan (isomers c - and 13 - and metabolite endosulfan sulfate) ranged between 0.5 and 16.0 ng mL-I with r2 > 0.967. The method developing consist of selecting the extraction solvent system by agitation (90 rpm, 1 hour) with n-hexan,e (2 mL) or n-hexane:acetone (1:1, v/v) (2 mL), concentration the extract with a gentle N2 stream, and evaluation of breakthrough with passage or air through the fortified XAD-2 cartridge before extraction, employing a low volume air suction pump (Pump Model 224 universal-PCXR8; 5-5000 mL min-1, SKC Inc., Eighty Four, PA, USA), Calibrator Dry-Cal DC-Lite (BIOS, Butler, NJ, USA)). Two fortification levels were employed, 15 and 30 ng. After selecting n-hexane as extraction solvent, with accuracy and precision ranging...

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

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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This work had with objective to characterize and evaluate the performance of the combined system, involving activated charcoal and ionic exchange resins in the removal of substances organic contaminating of the ethyl alcohol from the fermentation of the cassava starch. To testing was used ethyl alcohol PA 96 oGL, conductivity of 0.90 μS/cm at 25 oC, acidity of 60 mg/L and Barbet test of 43 minutes at 15 oC. The contaminated alcohol was composed of ethyl alcohol additive of higher alcohols, organic acids, ester, diol, aldehydes, ketone and ether. Contaminated alcohol was added 2% activated charcoal and after the adsorption isotherm in ionic exchange resins was tested. The adsorption with activated charcoal was performed in a Water Bath at 30 oC for one hour and a half and shaking. Already adsorption ionic exchange columns occurred at room temperature on columns of 93,4 cm in filling height and diameter of 2.29 cm, for flows of 180 mL/min and 90 mL/min. Samples were collected in the tests with charcoal and with each one of the resins and the following analyses were performed: conductivity, acidity and Barbet test. The medium values for conductivity, acidity and Barbet test after the adsorption in charcoal and cation and anion resins were respectively: conductivity was 240; 354 and 465 μS/cm to 25 oC; acidity of 1.081; 1.103 and 1.062 mg/L and the Barbet test was 21; 20 and 9 minutes to 15 oC. It was observed that the addition of 2% of activated charcoal and the permanence in the columns of adsorption was not sufficient to remove the organic substances contaminating of the ethyl alcohol.

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

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This study aimed to evaluate the use of a mixer to determine the rheological properties of fluids. The mixer is comprised of an agitation tank and an anchor type impeller. The tests were performed with honey and fruit juices (orange, guava and peach). The rheological characterization was performed using data from the torque and rotation speed required for the operation of fluid agitation. Tests were also made with a concentric cylinder rotational viscometer with the samples being subjected to various shear rates. The rheological parameters were obtained from the flow curves fitted to the power law model. Analyses of results showed that the mixer can be used, within its limitations, to determine rheological properties.

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O presente trabalho foi desenvolvido no Centro de Raízes e Amidos Tropicais – CERAT, Na UNESP em Botucatu, estado de São Paulo onde foram realizados ensaios de fermentação alcoólica com hidrolisado de amido de mandioca. A fécula de mandioca foi utilizada como fonte de carboidrato para obtenção dos açúcares redutores consumidos no processo. Em um reator agitado foi produzido 12Kg de hidrolisado a partir de suspensão de fécula a 30% (p/p) utilizando enzimas alfa amilase na primeira etapa, seguida de amiloglucosidase na etapa posterior. As dosagens em unidades enzimáticas foram 2KNU.g-1 de amido e 2AGU.g-1 de amido respectivamente. O planejamento experimental considerou a realização de três ensaios de hidrolisados e três ensaios de fermentação a partir do mosto produzido; a) mosto aerado; b) com microaeração; c) em meio anaeróbio. Os ensaios foram realizados em erlenmeyers com 2,5 Kg de hidrolisado, ajustado a concentração de glicose a 100g.L-1 sendo inoculada a levedura do gênero Saccharomyces cerevisiae à taxa de 1,5% (p/p). Todos os erlenmeyers foram colocados sob agitação orbital e temperatura controlada de 30ºC sendo acompanhado o processo de fermentação através de coleta de amostras do mosto a cada hora. A aeração nos frascos erlenmeyers foi realizada através de mangueira coletora de válvula que regulava a vazão de ar. De acordo com os dados obtidos pode se concluir que o sistema anaeróbio em 32h foi o mais eficiente para a produção de etanol. Também foi possível observar que enquanto ocorre aeração no meio não se observa alteração significativa na concentração de etanol e quando cessa a aeração o meio torna se anaeróbio e tem início a produção de etanol. Quando aumenta a concentração de etanol no meio, o crescimento celular do sistema anaeróbio cai e etanol inibe a levedura, parando o crescimento celular.

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Aiming to get the best economic advantage in ethanol production from cassava roots, this study presented a physiochemical characterization from two different types of solid waste in two types of processing of the raw materials in manufacturing ethanol. The processing of cassava roots begins with the disintegration and washing the roots with the addition of 20% more water to obtain a pulp which was treated and stirred in the reactor while adding enzyme α-amylase at a temperature of 90°C for 2 hours. Then we performed a pH adjustment while lowering the temperature to 60 ° C with the addition of the enzyme amiloglucosidase and then stirring for 14 hours. The hydrolyzate obtained was the source of two types of waste which are: i) Solid residue obtained after filtration of the hydrolyatze and ii) Solid waste obtained from filtering wine after alcoholic fermentation of the hydrolyzate with the addition of a dried yeast strain Y-940 manufactured by MAURI OF BRAZIL SA (2%) at a temperature of 25º C. The results of the laboratory analysis showed that the byproducts derived from the hydrolysis and fermentation showed very similar chemical compositions. With levels between 39 and 41% fiber, 0.5% lipids, 20 and 30% carbohydrates, protein 0.5 and 1.50, 6 and 8% acidity, and 20 and 30% soluble solids.

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Stress relates to the broad and generalized body's responses to various environmental, physical and social situations. It is the force that drives the emotions and motives (desires), but is also the cause of the wear and tear of human existence. This study aims to investigate the stressors in administrative technical servers Univ. Estadual Paulista - UNESP, Bauru, as well as on companies providing service within the perimeter of the campus. Was used as a methodology, literature and field research, a questionnaire was applied in order to reach those goals. The profiles of employees who participated in the survey were: both sexes, adults, young people with different educational levels, varying levels of marital and socioeconomic status. The main stressors mentioned by the employees were: workload, dissatisfaction in the workplace, pressure boss or colleagues, as they bring consequences, fatigue or drowsiness, affecting the work environment and mostly family. Physical symptoms of stress are fatigue, difficulty relaxing and headache, and backache. And the psychological symptoms are verbalized concern, agitation, aggression, dissatisfaction, and forgetfulness and feeling of lack of time. It was concluded that these factors negatively affect the quality of life in the work of these employees, interfering with your work, family and socio-emotional life.