923 resultados para SLA (Sand blasting and acid etching)


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The propagation of 'juçara' and 'açaí' is done by seeds, but there is a great desuniformity in the germination process. In this way, the objective of this study was to verify the effect of temperature, mechanical scarification and substrate on seed germination of both species. Two experiments were conducted in a completely randomized design, with four replications each consisting of 25 seeds. The first was conducted with 14 treatments in factorial scheme 7 x 2, seven temperatures (20, 25, 30, 35, 20-30 and 25-35 °C and natural condition), with and without mechanical scarification. The second was constituted of eight treatments in factorial scheme 4 x 2, four substrates (sand, vermiculite, coconut fiber and soil + manure), with and without mechanical scarification. Seeds of 'juçara' palm present the highest mean percentage and germination speed index in alternating temperatures of 20-30 and 25-35 °C and natural condition and in substrates sand, vermiculite and coconut fiber. Temperatures of 30, 35, 20-30 and 25-35 °C and natural condition in all substrates tested were the most favorable condition for 'açai' seeds. The scarification of the seeds was favorable to the germination process of 'juçara' whereas the seeds of açaí does not need to be scarified.

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The objective of this trial was to evaluate the effect of the addition of chemical and bacterial additive in the ensiling of sugar cane (Saccharum officinarum L.) on chemical composition, pH, kinectic fraction and in situ degradation of nutritions components of silages. Five rumen-cannulated 1/2 Simental + 1/2 Zebu steers were allotted to a completely randomized design. The steers were placed in individual cages and they were fed with diets with 76% forage (%DM). Five silages were evaluated: control - sugar cane, no additives; urea - sugar cane + 0.5% of urea (wet basis); inoculant - sugar cane inoculated with LactoSilo® (390 g/40 t forage); NaOH - sugar cane + 1.0% of sodium hydroxide (wet basis); CaOH - sugar cane + 0.6% of calcium hydroxide (wet basis). The silage additives with sodium hydroxide showed the highest pH values before (11.20) and after (4.87) for silage. No differences were observed among the silages for dry matter (26.85), crude protein (5.25) and acid detergent fiber (57.21). Fractionation of dry matter and organic matter of silages showed similar behavior, with higher values of the soluble fraction (fraction A) for silages with sodium hydroxide (45.86 and 30.95%) and calcium hydroxide (29.47 and 26.13%). The use of sodium hydroxide allowed obtaining higher values for the degradation of cell wall components of silages from cane sugar. The potencial and effective degradability with 3, 5 and 8%/h of passage rate were respectively 88.44, 64.45, 56.73 and 49.83% for NDF and 82.57, 55.51, 46.72 and 38.83% for ADF, indicating that the use of sodium hydroxide as chemical additives can improve the nutritive value of cane sugar silage.

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Characterization by micro-Raman spectroscopy of polymeric materials used as nuclear track detectors reveals physico-chemical and morphological information on the material's molecular structure. In this work, the nuclear track detector poly(allyl diglycol carbonate), or Columbia Resin 39 (CR-39), was characterized according to the fluence of alpha particles produced by a 226Ra source and chemical etching time. Therefore, damage of the CR-39 chemical structure due to the alpha-particle interaction with the detector was analyzed at the molecular level. It was observed that the ionization and molecular excitation of the CR-39 after the irradiation process entail cleavage of chemical bonds and formation of latent track. In addition, after the chemical etching, there is also loss of polymer structure, leading to the decrease of the group density C-O-C (∼888 cm-1), CH=CH (∼960 cm -1), C-O (∼1110 cm-1), C-O-C (∼1240 cm -1), C-O (∼1290 cm-1), C-O (∼1741 cm -1), -CH2- (∼2910 cm-1), and the main band -CH2- (∼2950 cm-1). The analyses performed after irradiation and chemical etching led to a better understanding of the CR-39 molecular structure and better comprehension of the process of the formation of the track, which is related to chemical etching kinetics. Copyright © 2013 Society for Applied Spectroscopy.

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Considering the importance of knowledge of the spatial distribution of soil properties, the purpose of this study was to evaluate the spatial variability of physical properties in a Cambisolunder different land uses in the southern Amazon region. The study was conducted on three farms with cassava, sugarcane, and agroforestry, in the region of Humaitá, in the south of the State of Amazonas. In these areas, 70 x 70 m grids were established, with a regular spacing of 10 x 10 m and a total of 64 points, where soils were sampled at 0.0-0.10 m depth. Texture (sand, silt, and clay), macroporosity, microporosity, total porosity, bulk density, and aggregate stabilitywere determined. The data were analyzed using descriptive statistics and geostatistics. It was found that the propertiesvaried spatially and that the range of these variations between land uses was different, with the highest variability for the sugarcane management.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Pós-graduação em Ciência Animal - FMVA

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)