987 resultados para Dependência química


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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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O manejo químico de espécies de cobertura do solo é prática usual em sistemas de semeadura direta, e a mineralização de nutrientes dos restos vegetais deixados na superfície do solo pode ser intensificada pela ação da água da chuva ao longo da senescência das plantas submetidas ao herbicida. Avaliou-se a lixiviação de K da palha de seis espécies vegetais com potencial de uso como plantas de cobertura do solo, utilizando chuvas simulada em diferentes estádios após a dessecação química. Milheto (Pennisetum glaucum), sorgo de guiné (Sorghum vulgare), aveia preta (Avena strigosa), triticale (Triticum secale), crotalária juncea (Crotalaria juncea) e braquiária (Brachiaria decumbens) foram cultivados em vasos, em casa de vegetação, em Botucatu (SP). Aos 50 dias da emergência, as plantas foram manejadas com herbicida pós-emergente não-seletivo e submetidas à chuva simulada de 30 mm, aos 2, 4, 8 e 16 dias da dessecação, considerando uma quantidade de palha equivalente a 8,0 t ha-1 de matéria seca. As quantidades de K lixiviado das palhas aumentaram, à medida que o estado de senescência das plantas evoluiu após o manejo químico. No que diz respeito à nutrição potássica da cultura subseqüente, a palha do triticale apresentou-se como a melhor alternativa, uma vez que disponibilizou um montante de mais de 9 kg ha-1 de K até 16 dias após a dessecação química das plantas.

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O experimento teve como objetivo avaliar a distribuição das raízes do maracujazeiro-doce (Passiflora alata Dryand), cultivado em Nitossolo Vermelho, sob adubação química e orgânica, em Botucatu-SP. Foram utilizadas plantas com 19 meses de idade, em produção, conduzidas em latada e com irrigação. Os tratamentos com fertilizantes químicos e esterco de curral curtido foram os seguintes: T1 (400 g de sulfato de amônia), T2 (2,5kg de esterco), T3 (5,0kg de esterco), T4 (7,5kg de esterco) e T5 (10,0kg de esterco), acrescidos de 200g de termofosfato, 137g de cloreto de potássio e 2,0kg de calcário por planta, em todos os tratamentos, parcelados em duas aplicações. Foram empregadas 3 plantas por tratamento, sendo retiradas quatro amostras de cada uma, a 0-20 e 20-40cm de profundidade e distância do tronco. Os resultados evidenciaram que não houve diferenças significativas entre os tratamentos para massa seca das raízes. em todos os tratamentos, houve concentração das raízes a 0-20cm de distância do tronco. Nas parcelas com adubo orgânico, houve melhor distribuição das raízes em profundidade.

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Avaliou-se o efeito do esterco de curral curtido na adubação de formação do pomar de tangerineira 'Poncã' (Citrus reticulata, Blanco), comparando com a adubação química convencional. O experimento foi conduzido na Fazenda Experimental São Manuel da Faculdade de Ciências Agronômicas da UNESP, Câmpus de Botucatu-SP. Os tratamentos foram aplicados na adubação de formação do pomar durante dois anos. No primeiro ano, utilizaram-se 7,5; 15,0; 22,5 e 30,0 kg planta-1 de esterco de curral curtido e 400 g planta-1 de sulfato de amônio. Na adubação de formação do segundo ano, as doses de esterco de curral foram 15,0; 22,5; 30,0 e 37,5 kg planta-1 e 800 g planta-1 de sulfato de amônio. Nos dois anos, a adubação foi parcelada em três aplicações. Realizaram-se as avaliações aos 30; 150 e 270 dias após a última parcela de adubação do segundo ano, determinando-se: altura da planta, diâmetro do caule, volume, projeção e circunferência da copa. O delineamento experimental foi inteiramente casualizado, em parcelas subdivididas no tempo, e 3 repetições, sendo as parcelas representadas pela adubação e as subparcelas pelas épocas de avaliação. Verificou-se que, na média das avaliações, houve aumento linear das características avaliadas com o incremento das doses de esterco de curral curtido. Não houve diferença significativa entre os tratamentos com adubo orgânico e químico.

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Avaliaram-se a composição química da madeira e da casca de sete espécies (E. saligna E. grandis, E. urophylla, E. camaldulensis, E. citriodora, E. paniculata e E. pellita) e três clones de eucalipto (híbridos de E. grandis x E. urophylla), antes e durante o cultivo das linhagens LE-95/01 e LE-96/18 de shiitake (Lentinula edodes), em toras. Cada linhagem de shiitake foi inoculada em nove toras de cada tipo de eucalipto com 1 m de comprimento e 9 a 14 cm de diâmetro. Assim, o delineamento experimental foi inteiramente casualizado, com 20 tratamentos e nove repetições, sendo cada repetição correspondente a uma tora. As toras foram mantidas em estufa climatizada, com temperatura de 25 ºC ± 5 e umidade relativa do ar entre 60-80%, durante 12 meses. Para a determinação da composição química da madeira, analisaram-se cunhas de discos e cascas de eucalipto recém-cortadas (sem inoculação das linhagens de L. edodes) e cunhas de discos e cascas retirados de toras já inoculadas com as linhagens de L. edodes após oito meses de incubação. Os resultados mostraram diferenças nos teores de holocelulose, lignina e extrativos totais na madeira e casca após o corte e depois de oito meses de incubação nas espécies e clones de eucalipto; o maior índice de decomposição da holocelulose na madeira, ao longo do tempo, ocorreu no E. saligna (5,5%), indicando, assim, ser o mais favorável para o desenvolvimento micelial do L. edodes. Já na casca aconteceu no clone 24 (22,2%). O E. camaldulensis apresentou o maior índice de decomposição da lignina na madeira (6,8%), ao longo do tempo. Já na casca, entre os eucaliptos testados, o E. grandis sofreu a maior decomposição de lignina (21,9%); o L. edodes degradou muito mais a holocelulose e lignina da casca que da madeira, tornando evidente a importância da casca; a casca da maioria dos tipos de eucaliptos apresentou menor teor de holocelulose, maior teor de extrativos totais e teores de lignina semelhantes ou superiores quando comparados com a madeira. O fator tipo de eucalipto (espécies e clones) teve maior efeito que o fator linhagem de L. edodes na degradação da holocelulose e lignina.

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Milk from different animals can be used for dairy production. Yoghurt is a popular fermented milk product and considered to be one of the greatest importance in terms of consumer acceptance and consumption. The present research deals with the production of strawberry set-type yoghurt by mixing goat and buffalo s milk and it has the objective of taking advantage of the intrinsic characteristics of each milk to produce a final product with desirable attributes. It was conducted by analyzing five experimental groups with different proportions of goat and buffalo s milk: C 100% goat s milk; 7C3B - 70% goat s milk and 30% buffalo s milk, 5C5B - 50% goat s milk and 50% buffalo s milk, 3C7B 30% goat s milk and 70% buffalo s milk; B - 100% buffalo s milk. Each group was evaluated for total solids content and the acidification profile was monitored every 30 minutes by pH analysis. The yoghurt samples were analyzed for physical-chemical (pH, acidity, protein, fat, total and reducing sugars, ash and total solids), rheological (syneresis and viscosity) and sensory characteristics (appearance, odor, consistency and flavour). Samples with higher percentual of bubaline milk reached Vm faster, but the time necessary for pH 4.6 (Te) were similar between groups. Statistical differences (p<0.05) were observed for fat and total solids content of yoghurt, with superior values for groups higher proportions of buffalo s milk. The parameters of behavior reached by the model of Ostwald of Waale pointed yoghurt samples as non-Newtonian and pseudoplastic fluids. Yoghurt made only with goat s milk (C) had higher values (p<0.05) for syneresis, which can be explained by its fragile coagulum. Additionally, this group also had the lowest sensory scores for the attributes consistence and taste, while bubaline yoghurt (B) obtained the best acceptance indexes for all of the appraised parameters

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Algaroba (Prosopis juliflora) is a typical legume from arid and semi arid regions, which is composed by sugar-rich pods and high protein seeds. Phenolic compounds are secondary metabolites recognized as potent bioactive compounds, found in several vegetables.Therefore, the objective of this work is to characterize the algaroba flour in terms of its physicalchemical composition, total phenolic content, antioxidant activity by DPPH and ABTS methods, a-amylase and a-glycosidase inhibition, as well as to analyze its organic compounds by high performance liquid chromatography (HPLC). Three experimental groups were investigated (seeds, seeds and pod together and only pod), which were prepared by oven drying and posterior grinding. Water and ethanol extracts (70, 80, 100% v/v) were prepared and used for functional studies. Organic compounds were detected by using HPLC equipment coupled to mass spectrometer. Results show important physical-chemical differences among the experimental groups, seeds, seeds and pod together and only pod. The algarroba seed flour is high in protein (49.49%) and fat (3.10%), while the pod flour is especially rich in sugar (60.3% to 67.9%). Algaroba phenolics are concentrated in pod flour, mainly in water extracts (1.30 mg GAEQ/100g sample). All seed extracts showed high DPPH activity and maximum antioxidant activity was registered for ethanol 80% extracts (19.81 μM Trolox/g sample). The ABTS activity ranged from 9.73 to 12.74 μM Trolox/g sample. Nearly all the extracts were able to inhibit α-amylase activity mildly (30.50% to 48.80%), while the maximum α-glycosidase inhibition was observed for pod water extracts (81.03%). Algaroba water extracts proven to be especially rich in organic compounds, observed by the high number of chromatographic peaks. Results demonstrate that algaroba is a potential candidate for further investigations concerning its possible functional applications

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This dissertation aims to assess the representativeness of the manual chilled mirror analyzer (model II Chanscope 13-1200-CN-2) used for the determination of condensed hydrocarbons of natural gas compared to the indirect methods, based on thermodynamic models equation of state. Additionally, it has been implemented in this study a model for calculating the dew point of natural gas. The proposed model is a modification of the equation of state of Peng-Robinson admits that the groups contribution as a strategy to calculate the binary interaction parameters kij (T) temperature dependence. Experimental data of the work of Brown et al. (2007) were used to compare the responses of the dew point of natural gas with thermodynamic models contained in the UniSim process simulator and the methodology implemented in this study. Then two natural gas compositions were studied, the first being a standard gas mixture gravimetrically synthesized and, second, a mixture of processed natural gas. These experimental data were also compared with the results presented by UniSim process simulator and the thermodynamic model implemented. However, data from the manual analysis results indicated significant differences in temperature, these differences were attributed to the formation of dew point of water, as we observed the appearance of moisture on the mirror surface cooling equipment

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Despite the relatively organized cashew (Anacardium occidentale L.) productive chain and the number of cashew derivatives found in the market, it is estimated that over 90% of the cashew peduncle is wasted. A possible strategy for a better commercial exploitation of this agroindustrial commodity would be the production of spray dried cashew pulp. Thus, this paper approaches the yellow cashew pulp spray drying process and the final product evaluation. Based on that, the shelf life of the spray dried cashew pulp packed in different packaging was evaluated. Drying was conducted in two drying temperatures (140 °C to 150 °C) and two concentrations of Arabic gum (AG, 15% and 25%), which summed four experimental groups. The drying performance was evaluated as well as the physicochemical characteristics (moisture, water activity, total soluble solids, pH, density, solubility, particle diameter, hygroscopicity, degree of caking, color, scanning electronic microscopy and X-ray diffraction), composition (protein, ash, fat and sugars) and bioactive and functional value (total phenolic compounds, carotenoids, ascorbic acid and antioxidant activity) of the final products. Results showed spray drying efficiency higher than 65% for all experiments, mainly for the C4 group (150 °C and 25% AG) which reached efficiency of 93.4%. It was also observed high solubility (94.7% to 97.9%) and the groups with lower hygroscopicity (5.8% and 6.5%) were those with the highest proportion of drying coadjuvant. The particle diameters ranged between 14.7 μm and 30.2 μm and increased with the proportion of AG. When comparing the product before and after spray drying, the drying impact was evident. However, despite the observed losses, dried yellow cashew showed high phenolic concentration (from 235.9 to 380.4 mg GAE eq / 100 g DM), carotenoids between 0.22 and 0.49 mg/100 g DM and remarkable ascorbic acid levels (852.4 to 1346.2 mg/100 g DM), in addition to antioxidant activity ranging from 12.9 to 16.4 μmol TE/ g DM. The shelf life study revealed decreased phenolic content over time associated to a slight water activity increase. Overall, our results unveil the technological and bioactive potential of dried yellow cashew as a functional ingredient to be used in food formulations or as a ready-to-use product. The technological approach presented here can serve as an efficient strategy for a rational use of the cashew apple, avoiding its current underutilization

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The aim of this work is to use a new technology in the treatment of produced wastewaters from oil industry. An unit for treat produced waters called UTMDIF, was designed, installed and operated in an industrial plant for treatment of effluents from oil industry. This unit operates by means of the method of separation of phase inversion and can become a promising alternative to solve the problem of oil/water separation. This method constitutes the basis of the working of a new design of mixersettler of vertical configuration which occupies small surface area. The last characteristic becomes specially important when there is limitation on the lay-out of the plant, for example, over maritime platforms to explore oil. This equipment in a semi-industrial scale treats produced wastewaters contaminated with oil at low concentrations (ranging from 30 to 150 mg/L) and throughputs of 320 m3/d (47,4 m3 m-2 h-1). Good results were obtained in oil/water separation which leads to the necessary specification to discharge those wastewaters. Besides, the non dependence of the efficiency of separation in spite of the salinity of the medium becomes the equipment an attractive new technology to treat wastewaters containing oil at low concentrations

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The objective of this research was to evaluate some soil chemical attributes and the nutritional status of 'Ponkan' mandarin managed with organic residues and chemical fertilization. The experiment was carried out at the Natural Resource Department-Soil Science Area, in the College of Agronomic Sciences -UNESP/Botucatu, SP. 'Ponkan' Mandarin seedlings were cropped and managed using the organic residues sewage sludge, cattle manure and chemical fertilization. The results allow the conclusion that there was an increase in the CEC, OM, N-total, P and K values in the soil managed with organic residues. The sewage sludge application did not harm the soil quality because the input of elements As, Cd, Cr and Hg present in its constitution were not significant. The soil management with organic residues increased significantly contents of N, P, Ca and S in 'Ponkan' leaves but did not contribute to increase significantly the elements B, Cu, Fe, Mn, Zn, As, Cd, Cr and Pb. The soil management with sewage sludge did not result in significant increase in the As, Cd, Cr and Hg content of leaves and fruits.

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The aim of the present study was to extract vegetable oil from brown linseed (Linum usitatissimum L.), determine fatty acid levels, the antioxidant capacity of the extracted oil and perform a rapid economic assessment of the SFE process in the manufacture of oil. The experiments were conducted in a test bench extractor capable of operating with carbon dioxide and co-solvents, obeying 23 factorial planning with central point in triplicate, and having process yield as response variable and pressure, temperature and percentage of cosolvent as independent variables. The yield (mass of extracted oil/mass of raw material used) ranged from 2.2% to 28.8%, with the best results obtained at 250 bar and 50ºC, using 5% (v/v) ethanol co-solvent. The influence of the variables on extraction kinetics and on the composition of the linseed oil obtained was investigated. The extraction kinetic curves obtained were based on different mathematical models available in the literature. The Martínez et al. (2003) model and the Simple Single Plate (SSP) model discussed by Gaspar et al. (2003) represented the experimental data with the lowest mean square errors (MSE). A manufacturing cost of US$17.85/kgoil was estimated for the production of linseed oil using TECANALYSIS software and the Rosa and Meireles method (2005). To establish comparisons with SFE, conventional extraction tests were conducted with a Soxhlet device using petroleum ether. These tests obtained mean yields of 35.2% for an extraction time of 5h. All the oil samples were sterilized and characterized in terms of their composition in fatty acids (FA) using gas chromatography. The main fatty acids detected were: palmitic (C16:0), stearic (C18:0), oleic (C18:1), linoleic (C18:2n-6) and α-linolenic (C18:3n-3). The FA contents obtained with Soxhlet dif ered from those obtained with SFE, with higher percentages of saturated and monounsaturated FA with the Soxhlet technique using petroleum ether. With respect to α-linolenic content (main component of linseed oil) in the samples, SFE performed better than Soxhlet extraction, obtaining percentages between 51.18% and 52.71%, whereas with Soxhlet extraction it was 47.84%. The antioxidant activity of the oil was assessed in the β-carotene/linoleic acid system. The percentages of inhibition of the oxidative process reached 22.11% for the SFE oil, but only 6.09% for commercial oil (cold pressing), suggesting that the SFE technique better preserves the phenolic compounds present in the seed, which are likely responsible for the antioxidant nature of the oil. In vitro tests with the sample displaying the best antioxidant response were conducted in rat liver homogenate to investigate the inhibition of spontaneous lipid peroxidation or autooxidation of biological tissue. Linseed oil proved to be more efficient than fish oil (used as standard) in decreasing lipid peroxidation in the liver tissue of Wistar rats, yielding similar results to those obtained with the use of BHT (synthetic antioxidant). Inhibitory capacity may be explained by the presence of phenolic compounds with antioxidant activity in the linseed oil. The results obtained indicate the need for more detailed studies, given the importance of linseed oil as one of the greatest sources of ω3 among vegetable oils

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The work aimed to study the formation of Tabebuia chrysotricha Standl. seedlings in function of four substrates, varying the covering fertilization solutions. To compose the substrate it was used fibrous and granulated coconut fiber obtaining the following treatments: 100% fibrous (100% F), 60% fibrous + 40% granulated (60% F+40% G), 40% fibrous + 60% granulated (40% F+60% G) and 100% granulated (100% G). The basis fertilization was the same for all treatments and the solutions of covering fertilization varied in order to obtain complete solutions with electric conductivities of 1.06 dS m(-1), 2.12 dS m(-1), 3.2 dS m(-1) and 4.25 dS m(-1). The propagative material was sowed directly in plastic containers (120mL) with the respective substrates. The fertilization was received through sub-irrigation once a week, respecting the treatments of fertilizations. Seedlings produced in 100%G had been taller and higher than the others. The chemical analyses of aerial part were obtained when the seedlings were ready for expedition (height of 20 cm). The seedlings production in substrate 100% F and 60% F+40% G allowed them to have higher N, S, B, Mn and Zn concentrations in the aerial part. The production of T chrysotricha seedlings is recommended in granulated coconut fiber substrate and fertilizer solutions with EC of 1.06 dS m(-1)

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The nonionic surfactants when in aqueous solution, have the property of separating into two phases, one called diluted phase, with low concentration of surfactant, and the other one rich in surfactants called coacervate. The application of this kind of surfactant in extraction processes from aqueous solutions has been increasing over time, which implies the need for knowledge of the thermodynamic properties of these surfactants. In this study were determined the cloud point of polyethoxylated surfactants from nonilphenolpolietoxylated family (9,5 , 10 , 11, 12 and 13), the family from octilphenolpolietoxylated (10 e 11) and polyethoxylated lauryl alcohol (6 , 7, 8 and 9) varying the degree of ethoxylation. The method used to determine the cloud point was the observation of the turbidity of the solution heating to a ramp of 0.1 ° C / minute and for the pressure studies was used a cell high-pressure maximum ( 300 bar). Through the experimental data of the studied surfactants were used to the Flory - Huggins models, UNIQUAC and NRTL to describe the curves of cloud point, and it was studied the influence of NaCl concentration and pressure of the systems in the cloud point. This last parameter is important for the processes of oil recovery in which surfactant in solution are used in high pressures. While the effect of NaCl allows obtaining cloud points for temperatures closer to the room temperature, it is possible to use in processes without temperature control. The numerical method used to adjust the parameters was the Levenberg - Marquardt. For the model Flory- Huggins parameter settings were determined as enthalpy of the mixing, mixing entropy and the number of aggregations. For the UNIQUAC and NRTL models were adjusted interaction parameters aij using a quadratic dependence with temperature. The parameters obtained had good adjust to the experimental data RSMD < 0.3 %. The results showed that both, ethoxylation degree and pressure increase the cloudy points, whereas the NaCl decrease

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Nowadays there are many reasons that aim to include people with special necessities, like those with visual deficiency, in the world of work, education, and in the society as a whole. However it is observed that when we talk about schooling inclusion, especially in High School, there is a huge gap between the theory and the practice. The lack of didactic resources, the inadequate installations, unprepared teachers, the families´ lack of information, are some of the factors that hinder the process of inclusion. Furthermore, the educators also have to deal with the roughness of the disciplinary contents and, refering to the study of Chemistry, with the use of signals related to this subject´s language. So, the objective of our research is to reflect about the apprehension of this language by the visually handicapped people, and try to contribute with their process of inclusion in the school life. On this perspective we work with the Periodic Table, which constitutes one of the indispensable tools necessary to the Chemistry learning. In order to acomplish it, the way followed by us happened in three passages. Initially, by means of a semistructured interview, we tried to get acquainted with the blind students opinion, who were participating in the research about the Periodic Table used by them throughout High School, as well as the dificulties felt when using it. After getting the answers, the Table was reelaborated to fill those students´necessities. Here, two new Tables were designed, one in Braille which shape is more compacted, and another made with high printed dots, built with sand and glue. On the third moment, the new designed Tables were tested by the students and, by means of a semi-structured interview, we tried to identify if this new resource would solve the problems concerned to the old Table. The students showed that the compacted Tables would facilitate the touch reading of the chemical elements simbols, making it clear and fast. We hope that, with the elaboration of this learning tools we can contribute with one of the elements to favor the effective participation of blind students in Chemistry classes, when studying the Periodic Table