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Search Results: 1 - 10 of 56545 matches for " Cristian Berto da Silveira "
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Composi??o química de um resíduo alcalino da indústria de papel e celulose (DREGS)
Almeida, Henrique Cesar;Silveira, Cristian Berto da;Ernani, Paulo Roberto;Campos, Mari Lucia;Almeida, Denice;
Química Nova , 2007, DOI: 10.1590/S0100-40422007000700032
Abstract: dregs is an alkaline solid by-product generated in the cellulose manufacturing industry that could be used to correct soil acidity. the present study aimed to evaluate the chemical composition of this product and some of its properties. the dregs presented 354 g kg-1 of calcium, neutralization capacity of 80.3%, and ph 10.7, besides low concentration of sodium (10.2 g kg-1), lead (62.9 mg kg-1) and cadmium (5.6 mg kg-1). thus, it is a product that can safely be used to increase the soil ph.
Effect of different salt concentrations on the reduction of bean (Phaseolus vulgaris) cooking time
Juliano Garcia Bertoldo,Jefferson Luís Meirelles Coimbra,Cristian Berto da Silveira,Diego Toaldo
Biotemas , 2008,
Abstract: The purpose of this work was to examine the effect of different saline concentrations on the cooking time of aged bean seeds. This experiment was conducted at the Molecular Genetics and Improvement Institute (IMEGEM / CAV), employing random block design with two repetitions, in a 2 x 4 factorial arrangement (two cultivars and four doses of NaCl). Two cultivars were tested, one belonging to the carioca group (Pérola) and the other belonging to the black group (Uirapuru). After weighing, the grains were imbibed in different sodium chloride (NaCl) concentrations (0g, 5g, 10g and 25g) for 12 hours at 25°C. Subsequently, these grains were submitted to a cooking test, using the Mattson cooking apparatus. It was then possible to determine the NaCl concentrations in which the cooking time presented a significant reduction. The Pérola cultivar cooking time was reduced by 31 minutes by the addition of 11g of NaCl and the Uirapuru cooking time was reduced by 25 minutes by the addition of 16.75g of NaCl.
Crystallization Mechanism and Kinetics of BaO-Li2O-ZrO2-SiO2 Glasses
Silveira, Cristian Berto da;Campos, Sílvia Denofre de;Campos, Elvio A. de;Oliveira, Ant?nio Pedro Novaes de;
Materials Research , 2002, DOI: 10.1590/S1516-14392002000100004
Abstract: differential thermal analysis and scanning electron microscopy were used to determine the influence of the addition of bao on the crystallization mechanism of li2o-zro2-sio2 systems. as the concentration of bao in the samples increased, a transition occurred in the predominant crystallization mechanism, which passed from superficial to volumetric. to determine the maximum nucleation rate, the crystallization kinetics of the sample containing 20 mole % bao, which showed the most uniform crystallization, was studied by counting the nuclei with an image analyzer. the first nuclei appeared at the first endothermic inflection point (at the start of tg, at 440 °c), while the maximum number of nuclei was counted at the midpoint of the glass transition region (446 °c). these results are similar to those observed for other materials that crystallize in volume, and confirm scanning electron microscopy data.
Resistência química de vitro-ceramicos pertencentes a sistemas Li2O-ZrO2-BaO-SiO2 frente ao tratamento com solu??es ácidas e básicas
Campos, Silvia Denofre de;Espíndola, Cláudio;Silveira, Cristian Berto da;Campos, élvio Ant?nio de;
Química Nova , 2002, DOI: 10.1590/S0100-40422002000200003
Abstract: the chemical durability of the li2o-zro2-bao-sio2 system was examined by determination of the vickers hardness. the dependence of hardness and of the chemical resistance with bao addition was investigated. the experimental results indicate that the hardness increases with the bao content. the samples surface's morphology submitted to the chemical treatment in acidic (h2so4) and basic (koh) solution was accompanied by scanning electron microscopy. the chemical durability of the materials with bao showed better than the glass ceramic without this content. these materials treated with h2so4 solution showed a preferential attack to the silica rich sites.
Crystallization Mechanism and Kinetics of BaO-Li2O-ZrO2-SiO2 Glasses
Silveira Cristian Berto da,Campos Sílvia Denofre de,Campos Elvio A. de,Oliveira Ant?nio Pedro Novaes de
Materials Research , 2002,
Abstract: Differential thermal analysis and scanning electron microscopy were used to determine the influence of the addition of BaO on the crystallization mechanism of Li2O-ZrO2-SiO2 systems. As the concentration of BaO in the samples increased, a transition occurred in the predominant crystallization mechanism, which passed from superficial to volumetric. To determine the maximum nucleation rate, the crystallization kinetics of the sample containing 20 mole % BaO, which showed the most uniform crystallization, was studied by counting the nuclei with an image analyzer. The first nuclei appeared at the first endothermic inflection point (at the start of Tg, at 440 °C), while the maximum number of nuclei was counted at the midpoint of the glass transition region (446 °C). These results are similar to those observed for other materials that crystallize in volume, and confirm scanning electron microscopy data.
Resistência química de vitro-ceramicos pertencentes a sistemas Li2O-ZrO2-BaO-SiO2 frente ao tratamento com solu es ácidas e básicas
Campos Silvia Denofre de,Espíndola Cláudio,Silveira Cristian Berto da,Campos élvio Ant?nio de
Química Nova , 2002,
Abstract: The chemical durability of the Li2O-ZrO2-BaO-SiO2 system was examined by determination of the Vickers hardness. The dependence of hardness and of the chemical resistance with BaO addition was investigated. The experimental results indicate that the hardness increases with the BaO content. The samples surface's morphology submitted to the chemical treatment in acidic (H2SO4) and basic (KOH) solution was accompanied by scanning electron microscopy. The chemical durability of the materials with BaO showed better than the glass ceramic without this content. These materials treated with H2SO4 solution showed a preferential attack to the silica rich sites.
Metodologias para reutiliza??o do resíduo de terra diatomácea, proveniente da filtra??o e clarifica??o da cerveja
Goulart, Marcos Roberto;Silveira, Cristian Berto da;Campos, Mari Lúcia;Almeida, Jaime Antonio de;Manfredi-Coimbra, Silvana;Oliveira, Aline Fernandes de;
Química Nova , 2011, DOI: 10.1590/S0100-40422011000400014
Abstract: the earth diatomite is a material used by the industries in the filtration process and clarification of the beer. this material presents a reduced useful life due to the blockages of their pores during the filtration process. the objective of this work was to reactivate the properties of filtration of the earth diatomite, saturated with organic matter during the filtration stage, starting from a controlled thermal treatment. the obtained results demonstrated that the earth diatomite saturated with organic matter submitted to a controlled thermal treatment has their filtration properties reactivated, could be reused in the beer production process.
Decomposi??o térmica de espumas de poliuretano para fabrica??o de vitroceramica celular de Li2O-ZrO2-SiO2-Al2O3 (LZSA)
Silveira, Cristian Berto da;Escobar, Jairo A.;Quintero, Miguel W.;Sousa, Eliandra de;Moraes, Elisangela Guzzi de;Oliveira, Ant?nio Pedro Novaes de;Rambo, Carlos Renato;Hotza, Dachamir;
Química Nova , 2007, DOI: 10.1590/S0100-40422007000500010
Abstract: characterization of the thermal decomposition of polyurethane (pur) foams was performed by fourier-transformed infrared (ft-ir) spectroscopy and thermogravimetric analysis (tga). three main weight loss paths were observed by tga, the residue being lower than 3 wt.% for 3 different pur foams analyzed. ft-ir spectra indicated co2, co, nh3 and isocyanides as main decomposition products. pur foams of different cell sizes were immersed in a slurry of the parent glass ceramic of composition li2o-zro2-sio2-al 2o3 (lzsa) and submitted to heat treatment. the lzsa cellular glass ceramics obtained after sintering and crystallization resembled the original morphology of the pur foams.
Yield and fruit quality of peach scion by using rootstocks propagated by air layering and seed
Picolotto, Luciano;Fachinello, José Carlos;Bianchi, Valmor Jo?o;Manica-Berto, Roberta;Pasa, Mateus da Silveira;Schmitz, Juliano Dutra;
Scientia Agricola , 2010, DOI: 10.1590/S0103-90162010000600005
Abstract: in rootstock propagation, several methods can be used; however few practices are adopted due to the lack of information about the behavior of stionic combinations at field. the work aimed to compare the propagation method by air layering with the traditional propagation system by seeds using the scion peach [prunus persica (l.) batsch] cultivar granada. the following variables were measured: yield, fruit weight and size, skin color, flesh firmness, total soluble solids content (tss) and titatrable acidity (ta), tss/ta ratio, total phenols, trunk diameter and pruning mass. yield, total phenols and titatrable acidity were higher when using the air layering propagation. there was no difference between propagation methods regarding color and diameter of fruit, flesh firmness and total soluble solid and tss/ta ratio. depending on propagation method, the fruit weight did not differ, nevertheless using the seed propagated capdeboscq rootstock fruit weight was heavier. plant behavior in each propagation method depended on the rootstock used. scion cultivar (cv.) granada on air layering rootstock-derived keeps similar or superior yield and same attributes of fruit quality, better than using rootstocks derived from seeds.
Como evitar perdas na ensilagem do milho
éder Cristian Malta de Lanes:,Julieta de Jesus da Silveira Neta:
REDVET , 2008,
Abstract: As perdas durante os processos da fermenta o, relacionadas às altera es químico-bromatológicas da forragem dependem das características da planta forrageira e est o associadas às práticas de implanta o, manejo e colheita das lavouras e ao sistema de armazenamento. O objetivo desta revis o é discutir os principais passos no processo de ensilagem do milho, afim de evitar ou reduzir perdas, oferecendo aos agricultores conhecimento e informa es para maior eficácia técnica e econ mica na atividade agropecuária. Vários aspectos causam varia es na qualidade da silagem, como o híbrido utilizado, estádio de matura o na colheita, além de aspectosrelativos ao solo e ao clima. O processo de ensilagem também é muitoimportante, onde o material colhido deve ser picado em partículas comtamanho entre 2 e 2,5 cm, devendo-se retirar todo o oxigênio de dentro do silo. Em seguida deve-se vedar o silo para impedir a entrada de ar e construir valetas e cercas para impedir a entrada de água e animais. No processo de ensilagem parte das perdas s o evitáveis, e para isso as técnicas corretas de ensilagem devem ser utilizadas pelo produtor. Outras, porém, s o inevitáveis, mas podem ser minimizadas através, também, do uso de boas técnicas de ensilagem.
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