152 resultados para Carbón orgánico


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Pós-graduação em Microbiologia Agropecuária - FCAV

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Pós-graduação em Agronomia - FEIS

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The enrichment of an organic compound with biofertilizers of microorganisms (solubilizing phosphorus bacteria, BSF) can improve the properties of phosphate fertilizers applied to soils to increase nutrient availability. The experimental design was randomized complete blocks with a factorial 4x2 +1 arrangement of treatments: 1) four sources of phosphorus: phosphate rock, natural phosphate, triple superphosphate (TSP) and Cuban phosphate rock; 2) two sources of bio-fertilizer prepared from filter cake (cane waste) enriched with microorganisms and no enrichment; 3) and an absolute control (no filter cake or fertilizer); repeated three times. Data was analyzed with ANOVA and treatment means were compared using Tukey (p <= 0.05). Assessments of available P (Bray-2 and Oniani methodology) and the quantification of total and solubilizing bacteria and fungi in the soil were performed 30, 60 and 90 d after starting the experiment. After 60 d, the population of BSF was lower in the control (p <= 0.05) and the content of P (Bray-2) was higher for SFT (p <= 0.01). The application of the bio-fertilizer increased the P content compared to the control. At 90 d P (Bray-2) increased with the SFT treatment, which also increased (p P in the soil at 60 and 90 d regardless of the presence of microorganism-enriched bio-fertilizer. The use of filter cake enriched with microorganisms associated with different sources of P, and applied to the soil with a high content of P, did not change the soil populations of total and solubilizing bacteria and fungi in the short term. TSP promoted the highest levels of P in the soil, irrespective of the presence of the organic compound enriched with P solubilizing microorganisms.

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Usually organic polymeric diodes are made with a semiconductor layer placed between two electrodes in a sandwich-like architecture, where the electrodes are deposited on the surfaces of a polymeric semiconductor film. This methodology leads to two main problems: i) the polymeric film top surface is rough and irregular, resulting in non-uniform electric field into the device; ii) during the deposition of metallic electrode in the top surface polymeric film, by thermal evaporation, occurs the diffusion of metal atoms into the polymeric film, changing the material electronic structure. Thus, the metal-semiconductor junction is not well defined, which is essential for the production of good quality Schottky diode, which exhibits ideality factor close to the unity and low turn-on voltage. In order to avoid these two problems, in the present research was proposed to manufacture an organic diode with the semiconductor polymeric layer deposited over bimetallic (gold and aluminum) interdigitated electrodes. The doping of the active layer was performed by immersing the device in hydrochloric acid solution with pH 2 during different times in order to promote different doping levels of the semiconductor polymer. Was verified that the proposed diode, which exhibits well-defined metal-semiconductor junction, operates as a Schottky diode, with good ideality factor, 10 ± 3, and low turn-on voltage, 1,2 ± 0,2 V, in comparison with conventional organic polymeric diodes. Contrasting with the ideality factor and turn-on voltage, the diode rectification ratio was obtained as 7, a value lower than the expected for a good organic diode. Was also showed that the diode characteristics were dependent on the semiconductor polymer doping level, and that the diode characteristics were optimized with doping promoted by immersion in the acid solution for times longer than 50 s. Furthermore, as was showed that the diodes properties are dependent on the semiconductor...

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

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Fabrication of optoelectronic devices requires the employment of at least one transparent electrode. Usually, commercially transparent electrodes have been made by deposition of indium tin oxide (ITO) films by RF-Sputtering technique. These commercial electrodes have sheet resistance of about 100 Ω/sq and optical transmittance of 77% at the wavelength of 550 nm. The poly(3,4-ethylenedioxythiophene):polystyrene-sulfonate (PEDOT:PSS) is an alternative material to fabricate transparent electrodes due to its high conductivity (about 600 S/cm) and solubility in water. Soluble conductive materials exhibits advantages for processing of electrode layers, however there is a disadvantage during devices fabrication once materials with the same solvent of the electrode material cannot be coated one over the other. Alternatively, organic/Silica hybrid materials prepared by sol-gel process allow producing bulks and films with high chemical durability. In order to obtain transparent electrodes with high chemical durability, we introduced a blended material comprising the high UV-VIS transparency of organic/Silica sol-gel material and a high conductivity polymer PEDOT:PSS. The organic/Silica sol was obtained using two different molar concentrations (1:1 and 4:1), of tetraethylorthosilicate (TEOS) and 3-glycidoxypropyltrimethoxysilane (GPTS). Amounts of PEDOT:PSS solutions were added to the sol material, resulting in different weight fractions of sol and polymer. G:T/P:P were deposit onto glass substrates by spray-coating. In order to perform electrical characterization of the blended material, gold electrodes were thermally evaporated onto the films. The electrical characterization was performed using a Keithley 2410 source/meter unity and the optical characterization, using a Cary50 UV-Vis spectrophotometer. The absorption coefficient and electric conductivity of the different compositions blends, as function of the PEDOT:PSS concentration, were...

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The concentration of nutrients in plant is related to the soil, fertilization, climate, season, cultivar and cultural practices. Aiming to evaluate the soil chemical properties, the dry matter production of shoots and roots, nutrient content in the plant and the chemical composition of the grass Tierra Verde subjected to levels of organic biofertilizer as nitrogen source, an experiment was conducted in a greenhouse at the Faculty of Veterinary Medicine , UNESP, Araçatuba-SP, January-September 2010. Treatments were arranged in a completely randomized design with six fertilized biofertilizer doses (0, 33, 66, 132, 264, 528 m3 ha-1) and five repetitions for three cuts. We used the model split plot, with doses of biofertilizer considered as main treatments and cuts as sub-plots. We obtained a linear response in the production of dry mass of shoots and roots to the dose of 528 m3 ha-1 of organic biofertilizer. Nitrogen fertilization influenced the soil chemical properties and levels of organic matter, sulfur, boron and manganese, and in foliar levels of phosphorus, potassium and copper. The chemical composition was not altered by the influence of organic biofertilizer doses applied to the soil.

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Conselho Nacional de Desevolvimento Científico e Tecnológico (CNPq)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Pós-graduação em Agronomia (Produção Vegetal) - FCAV

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Aimed at satisfying a market niche, organic coffee production is a competitiveness-oriented system because it has less input costs and higher income. This study estimates the system’s economic efficiency, using production costs end gross income as economic input and output. This model was designed from original survey data, reported by a sample of producers in different stages of production, which enabled the development of average technical coefficients. Results show that annual gross income exceeds operating costs by 21%, pointing therefore to an economically efficient system.

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In this study, organic coffee production systems energy efficiency was estimate. So, an itinerary technical was built since the deployment phase up to the organic coffee production. The inputs used (labor, machine hours, pesticides, fertilizers, etc.) converted into energy units, quantified the energy input, while the production of organic coffee beans benefited was constituted the energy output. Data collection was based on an intentional and non-probabilistic sampling. Nine farmers were interviewed whose main source of income was the coffee production and had keep records of the culture data. The balances were positive, with an energy yield of 626.465MJ.ha-1, compared to an energy expenditure of 112.998MJ.ha-1 during the crop cycle. It is concluded that organic coffee production is energy efficient.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)