986 resultados para Water production rates
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Net photosynthesis (A) and transpiration rates (E), stomatal conductance (g), water use efficiency (WUE), intrinsic water use efficiency (IWUE) and internal leaf CO2 concentration (C) in response to different vapor pressure deficit (1.2 and 2.5 kPa) were investigated in 'Pera' sweet orange plants affected by citrus variegated chlorosis (CVC), a disease caused by Xylella fastidiosa. All plants were well watered and leaf water potential (Pw) was also measured by the psychrometric technique. Results showed that healthy plants responded to higher vapor pressure deficit (VPD), lowering its net photosynthesis and transpiration rates, and stomatal conductance. However, diseased plants presented no clear response to VPD, showing lower A, E and g for both VPDs studied and very similar values to these variables in healthy plants at the highest VPD. Internal leaf CO2 concentration also decreased for healthy plants when under the highest VPD, and surprisingly, the same pattern of response was found in plants with CVC. These results, the lower Psi(w) and higher WUE values for diseased plants, indicated that this disease may cause stomatal dysfunction and affect the water resistance through xylem vessels, which ultimately may play some role in photosynthetic metabolism. (C) 2003 Elsevier B.V. B.V. All rights reserved.
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O objetivo deste trabalho foi selecionar o pré-tratamento químico mais apropriado para a secagem de uvas cv. Rubi para a produção de passas. Foram obtidas curvas de secagem convectiva com ar a 50ºC, em um secador de bandejas, para uvas submetidas a pré-tratamentos químicos com diferentes concentrações de carbonato de potássio e azeite de oliva, e diferentes tempos de imersão, de acordo com planejamentos fatoriais. Também foram obtidas curvas de secagem convectiva, para uvas pré-tratadas em suspensões aquosas de lecitina de soja, em várias concentrações de lecitina e diferentes tempos de imersão. O modelo de Page foi ajustado às curvas de secagem experimental, e os tempos de secagem calculados mostraram que o melhor pré-tratamento consistiu na imersão das uvas por 2 minutos, em uma emulsão de 5% de azeite de oliva e 6% de K2CO3, a 50ºC, o que resultou em tempos de secagem próximos aos do pré-tratamento com 2,5% de azeite de oliva, mas com um menor consumo dessa substância. Além disso, a imersão das uvas em uma suspensão aquosa de 2% de lecitina de soja, a 50ºC, por 5 minutos, resultou em um tempo de secagem total apenas levemente superior ao do pré-tratamento mais efetivo.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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The industrial production of antibiotics with filamentous fungi is usually carried out in conventional aerated and agitated tank fermentors. Highly viscous non-Newtonian broths are produced and a compromise must be found between convenient shear stress and adequate oxygen transfer. In this work, cephalosporin C production by bioparticles of immobilized cells of Cephalosporium acremonium ATCC 48272 was studied in a repeated batch tower bioreactor as an alternative to the conventional process. Also, gas-liquid oxygen transfer volumetric coefficients, k(L)a, were determined at various air flow-rates and alumina contents in the bioparticle. The bioparticles were composed of calcium alginate (2.0% w/w), alumina (<44 micra), cells, and water. A model describing the cell growth, cephalosporin C production, oxygen, glucose, and sucrose consumption was proposed. To describe the radial variation of oxygen concentration within the pellet, the reaction-diffusion model forecasting a dead core bioparticle was adopted. The k(L)a measurements with gel beads prepared with 0.0, 1.0, 1.5, and 2.0% alumina showed that a higher k(L)a value is attained with 1.5 and 2.0%. An expression relating this coefficient to particle density, liquid density, and air velocity was obtained and further utilized in the simulation of the proposed model. Batch, followed by repeated batch experiments, were accomplished by draining the spent medium, washing with saline solution, and pouring fresh medium into the bioreactor. Results showed that glucose is consumed very quickly, within 24 h, followed by sucrose consumption and cephalosporin C production. Higher productivities were attained during the second batch, as cell concentration was already high, resulting in rapid glucose consumption and an early derepression of cephalosporin C synthesizing enzymes. The model incorporated this improvement predicting higher cephalosporin C productivity. (C) 2004 Wiley Periodicals, Inc.
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The soil of the Paraiba, in generality, are acid and with low levels of available match, seriously limiting the income of the plants. A research in vegetation house was lead, with the objective to evaluate doses of calcareous soil and match in the culture of ricinus. The treatments had been composites for five levels of match: 0.0; 80; 160; 240 and 360 kg ha(-1) of P(2)O(5) and four dosis of calcareous rock: 0.0; 2.5; 3.5 and 4.5 t ha(-1) in experimental delineation of blocks casualized with 4 factorial project x 3 (four levels of match and three doses of calcareous soil) more two treatments you add zero of match (0.0 P(2)O(5): 2,5 t ha(-1) of calcareous soil) and calcareous soil zero (240 P(2)O(5): 0.0 t ha(-1) of calcareous soil), with three repetitions. The calcareous soil reduced the acidity of the ground and effect of the application of the match (>= 80 kg ha(-1) of P(2)O(5)) in the presence of the collagen (>= 2.5 t ha(-1) of CaCO(3)) with of the calcareous soil (>= 2.5 t ha(-1) of CaCO(3)) in the presence of the match was not verified well (>= 80 kg ha(-1) of P(2)O(5)). The match applied in the absence of the calcareous soil was limited to the income of the culture of what the calcareous soil in the absence of the match.
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Vegetated riparian buffer strips have been established in Southern Quebec (Canada) in order to intercept nutrients such as nitrate (NO(3)(-)) and protect water quality near agricultural fields. Buffer strips may also favour denitrification through a combination of high soil moisture, NO(3)(-) and carbon supply, which could lead to the production of nitrous oxide (N(2)O), a greenhouse gas. Denitrification could be further amplified by the presence of earthworms, or by plant species that promote earthworm and bacterial activity in soils. Soils from four farms, comprising maize fields and adjacent buffer strips, were sampled in the fall of 2008. A total of six earthworm species were found, but average earthworm biomass did not differ between buffer strips and maize agroecoecosystems. Nitrate concentrations and net nitrification rates were higher in the maize fields than in the buffer strips: there was no difference in N(2)O production in soils collected from the two sampling locations. Potential denitrification, measured by acetylene inhibition, varied by two orders of magnitude, depending on experimental conditions: when amended with H(2)O or with H(2)O + NO3-, potential denitrification was higher (P < 0.05) in soils from buffer strips than from maize fields. Potential denitrification was highest in soils amended with H(2)O+glucose, or with H(2)O+ NO(3)(-) + glucose. Using microcosms, we tested the effect of litter-soil mixtures on earthworm growth, and the effect of earthworm-litter-soil mixtures on potential denitrification. Based on four categories of chemical assays, litters of woody species (oak, apple, Rhododendron) were generally of lower nutritional quality than litter from agronomic species (alfalfa, switchgrass, corn stover). Alfalfa litter had the most positive effect, whereas apple litter had the most negative effect, on earthworm growth. Potential denitrification was 2-4 times higher in earthworm-litter-soil mixtures than in plain soil. Litter treatments that included corn stover had lower potential denitrification than those that included alfalfa or switchgrass, whereas litter treatments that included oak had lower potential denitrification than those that included apple or Rhododendron. Results suggest that potential N(2)O emissions may be higher in riparian buffer strips than in adjacent maize fields, that N(2)O emissions in buffer strips may be amplified by comminuting earthworms, and that plant litters that reduce earthworm growth may not be best at mitigating N(2)O emissions. (c) 2010 Elsevier B.V. All rights reserved.
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Sedimentation rates of particulate material and some physicochemical parameters of water were determined in October, January, April and July 1990-91 at seven stations in the Jurumirim Reservoir (São Paulo, Brazil), three located in the Paranapanema arm, three in the Taquari arm and one near the dam. Higher sedimentation rates of tripton were found in the Paranapanema arm, followed by those from the Taquari arm and the dam. Suspended matter (2.5-48.7 mg · 1-1) and chlorophyll-a (0.7-8.1 mg · m-3) concentrations in the Paranapanema arm were in general higher resulting in lower water transparency (0.3-1.7m) than in the Taquari arm. Temporal and spatial variations in the tripton sedimentation rates were mainly influenced by allochthonous input at the stations near the river mouth. The settling fluxes at station near the dam of the reservoir were affected rather by a small autochthonous production (65 g C ass m-2 ;yr-1), indicated by a higher organic content (64-87%). Therefore, sedimentation rates measured by bottom traps were affected by sediment ressuspension especially at isothermal conditions. With respect to sedimentation, the riverine, the transition and the lacustrine zones commonly found in reservoires could be distinguished. The extent of the riverine zone in each arm of the Jurumirim Reservoir depends on the seasonal change of allochthonous input.
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This work has as objective to demonstrate technical and economic viability of hydrogen production utilizing glycerol. The volume of this substance, which was initially produced by synthetic ways (from oil-derived products), has increased dramatically due mainly to biodiesel production through transesterification process which has glycerol as main residue. The surplus amount of glycerol has been generally utilized to feed poultry or as fuel in boilers, beyond other applications such as production of soaps, chemical products for food industry, explosives, and others. The difficulty to allocate this additional amount of glycerol has become it in an enormous environment problem, in contrary to the objective of biodiesel chain, which is to diminish environmental impact substituting oil and its derivatives, which release more emissions than biofuels, do not contribute to CO2-cycle and are not renewable sources. Beyond to utilize glycerol in combustion processes, this material could be utilized for hydrogen production. However, a small quantity of works (theoretical and experimental) and reports concerning this theme could be encountered. Firstly, the produced glycerol must be purified since non-reacted amounts of materials, inclusively catalysts, contribute to deactivate catalysts utilized in hydrogen production processes. The volume of non-reacted reactants and non-utilized catalysts during transesterification process could be reutilized. Various technologies of thermochemical generation of hydrogen that utilizes glycerol (and other fuels) were evaluated and the greatest performances and their conditions are encountered as soon as the most efficient technology of hydrogen production. Firstly, a physicochemical analysis must be performed. This step has as objective to evaluate the necessary amount of reactants to produce a determined volume of hydrogen and determine thermodynamic conditions (such as temperature and pressure) where the major performances of hydrogen production could be encountered. The calculations are based on the process where advance degrees are found and hence, fractions of products (especially hydrogen, however, CO2, CO, CH4 and solid carbon could be also encountered) are calculated. To produce 1 Nm3/h of gaseous hydrogen (necessary for a PEMFC - Proton Exchange Membrane Fuel Cell - containing an electric efficiency of about 40%, to generate 1 kWh), 0,558 kg/h of glycerol is necessary in global steam reforming, 0,978 kg/h of glycerol in partial oxidation and cracking processes, and 0,782 kg/h of glycerol in autothermal reforming process. The dry reforming process could not be performed to produce hydrogen utilizing glycerol, in contrary to the utilization of methane, ethanol, and other hydrocarbons. In this study, steam reforming process was preferred due mainly to higher efficiencies of production and the need of minor amount of glycerol as cited above. In the global steam reforming of glycerine, for one mole of glycerol, three moles of water are necessary to produce three moles of CO2 and seven moles of H2. The response reactions process was utilized to predict steam reforming process more accurately. In this mean, the production of solid carbon, CO, and CH4, beyond CO2 and hydrogen was predicted. However, traces of acetaldehyde (C2H2), ethylene (C2H4), ethylene glycol, acetone, and others were encountered in some experimental studies. The rates of determined products obviously depend on the adopted catalysts (and its physical and chemical properties) and thermodynamic conditions of hydrogen production. Eight reactions of steam reforming and cracking were predicted considering only the determined products. In the case of steam reforming at 600°C, the advance degree of this reactor could attain its maximum value, i.e., overall volume of reactants could be obtained whether this reaction is maintained at 1 atm. As soon as temperature of this reaction increases the advance degree also increase, in contrary to the pressure, where advance degree decrease as soon as pressure increase. The fact of temperature of reforming is relatively small, lower costs of installation could be attained, especially cheaper thermocouples and smaller amount of thermo insulators and materials for its assembling. Utilizing the response reactions process in steam reforming, the predicted volumes of products, for the production of 1 Nm3/h of H2 and thermodynamic conditions as cited previously, were 0,264 kg/h of CO (13% of molar fraction of reaction products), 0,038 kg/h of CH4 (3% of molar fraction), 0,028 kg/h of C (3% of molar fraction), and 0,623 kg/h of CO2 (20% of molar fraction). Through process of water-gas shift reactions (WGSR) an additional amount of hydrogen could be produced utilizing mainly the volumes of produced CO and CH4. The overall results (steam reforming plus WGSR) could be similar to global steam reforming. An attention must to be taking into account due to the possibility to produce an additional amount of CH4 (through methanation process) and solid carbon (through Boudouard process). The production of solid carbon must to be avoided because this reactant diminishes (filling the pores) and even deactivate active area of catalysts. To avoid solid carbon production, an additional amount of water is suggested. This method could be also utilized to diminish the volume of CO (through WGSR process) since this product is prejudicial for the activity of low temperature fuel cells (such as PEMFC). In some works, more three or even six moles of water are suggested. A net energy balance of studied hydrogen production processes (at 1 atm only) was developed. In this balance, low heat value of reactant and products and utilized energy for the process (heat supply) were cited. In the case of steam reforming utilizing response reactions, global steam reforming, and cracking processes, the maximum net energy was detected at 700°C. Partial oxidation and autothermal reforming obtained negative net energy in all cited temperatures despite to be exothermic reactions. For global steam reforming, the major value was 114 kJ/h. In the case of steam reforming, the highest value of net energy was detected in this temperature (-170 kJ/h). The major values were detected in the cracking process (up to 2586 kJ/h). The exergetic analysis has as objective, associated with physicochemical analysis, to determine conditions where reactions could be performed at higher efficiencies with lower losses. This study was performed through calculations of exergetic and rational efficiencies, and irreversibilities. In this analysis, as in the previously performed physicochemical analysis, conditions such as temperature of 600°C and pressure of 1 atm for global steam reforming process were suggested due to lower irreversibility and higher efficiencies. Subsequently, higher irreversibilities and lower efficiencies were detected in autothermal reforming, partial oxidation and cracking process. Comparing global reaction of steam reforming with more-accurate steam reforming, it was verified that efficiencies were diminished and irreversibilities were increased. These results could be altered with introduction of WGSR process. An economic analysis could be performed to evaluate the cost of generated hydrogen and determine means to diminish the costs. This analysis suggests an annual period of operation between 5000-7000 hours, interest rates of up to 20% per annum (considering Brazilian conditions), and pay-back of up to 20 years. Another considerations must to be take into account such as tariffs of utilized glycerol and electricity (to be utilized as heat source and (or) for own process as pumps, lamps, valves, and other devices), installation (estimated as US$ 15.000 for a plant of 1 Nm3/h) and maintenance cost. The adoption of emission trading schemes such as carbon credits could be performed since this is a process with potential of mitigates environment impact. Not considering credit carbons, the minor cost of calculated H2 was 0,16288 US$/kWh if glycerol is also utilized as heat sources and 0,17677 US$/kWh if electricity is utilized as heat sources. The range of considered tariff of glycerol was 0-0,1 US$/kWh (taking as basis LHV of H2) and the tariff of electricity is US$ 0,0867 US$/kWh, with demand cost of 12,49 US$/kW. The costs of electricity were obtained by Companhia Bandeirante, localized in São Paulo State. The differences among costs of hydrogen production utilizing glycerol and electricity as heat source was in a range between 0,3-5,8%. This technology in this moment is not mature. However, it allows the employment generation with the additional utilization of glycerol, especially with plants associated with biodiesel plants. The produced hydrogen and electricity could be utilized in own process, increasing its final performance.
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The municipality of Petrolina, located in the semi-arid region of Brazil, is highlighted as an important agricultural growing region, however the irrigated areas have cleared natural vegetation inducing a loss of biodiversity. To analyze the contrast between these two ecosystems the large scale values of biomass production (BIO), evapotranspiration (ET) and water productivity (WP) were quantified. Monteithś equation was applied for estimating the absorbed photosynthetically active radiation (APAR), while the new SAFER (Simple Algorithm For Evapotranspiration Retrieving) algorithm was used to retrieve ET. The water productivity (WP) was analysed by the ratio of BIO by ET at monthly time scale with four bands of MODIS satellite images together with agrometeorological data for the year of 2011. The period with the highest water productivity values were from March to April in the rainy period for both irrigated and not irrigated conditions. However the largest ET rates were in November for irrigated crops and April for natural vegetation. More uniformity of the vegetation and water variables occurs in natural vegetation, evidenced by the lower values of standard deviation when comparing to irrigated crops, due to the different crop stages, cultural and irrigation managements. The models applied with MODIS satellite images on a large scale are considered to be suitable for water productivity assessments and for quantifying the effects of increasing irrigated areas over natural vegetation on regional water consumption in situations of quick changing land use pattern. © 2012 SPIE.
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Contents: The osteopontin gene may influence the fertility of water buffaloes because it is a protein present in sperm. The aim of this work was to identify polymorphisms in this gene and associate them with fertility parameters of animals kept under extensive grazing. A total of 306 male buffaloes older than 18 months, from two farms, one in the state of Amapá and the other in the state of Pará, Brazil were used in the study. Seven SNPs were identified in the regions studied. The polymorphisms were in gene positions 1478, 1513 and 1611 in the region 5′upstrem and positions 6690, 6737, 6925 and 6952 in the region amplified in intron 5. The SNPs were associated with the traits, namely scrotal circumference, scrotal volume, sperm motility, sperm concentration and sperm pathology. There were significant SNPs (p < 0.05) for all the traits. The SNP 6690 was significant for scrotal circumference, sperm concentration, sperm motility and sperm pathology and the SNP 6737 for scrotal volume. The genotype AA of SNP 6690 presented the highest averages for scrotal circumference, sperm concentration and motility and the lowest total number of sperm pathologies. For the scrotal volume trait, the animals with the largest volume were correlated with the presence of the genotype GG of SNP 6737. These results indicate a significance of the osteopontin gene as it seems to exert a substantial influence on the semen production traits of male buffaloes. © 2013 Blackwell Verlag GmbH.
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The prevalence of and possible risk factors for tuberculosis were studied in water buffalo from Para, Brazil. In this study, 3,917 pregnant and nonpregnant female Murrah and Mediterranean buffaloes were studied; 2,089 originated from Marajo Island, and 1,108 were from the mainland. The comparative cervical tuberculin test was used as a diagnostic test for tuberculosis in these animals. The prevalence of positive buffaloes was 3.5 % (100/2,809) on Marajo Island and 7.2% (80/1,108) on the mainland. The municipalities with the highest tuberculosis prevalence rates in animals were Ipixuna do Para (10.1 %), Marapanim (9.8 %), Chaves (9.4 %), Paragominas (8.6 %), and Cachoeira do Arari (6.7 %). The tuberculosis prevalence was not significantly different between the Murrah (4.3 %) and Mediterranean (4.8 %) breeds or between pregnant (5%) and nonpregnant (4.3%) buffaloes. Tuberculosis was detected in water buffaloes from Para, Brazil; the mainland buffalo exhibited the highest tuberculosis prevalence. These results indicate that this disease is dangerous to public health and buffalo farming in Para.
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Potassium fertilization is very important to alfalfa crop in terms of yield, quality and persistence of forage, especially on soils naturally poor K. Thus, to assess the effects of K fertilization in alfalfa production and nutritional status, was carried out an experiment in a greenhouse using samples of a Dystrophic Oxisol medium texture (LV) (0.6 mmol(c) dm(-3) K) and a Dystrophic Ultisol sandy/medium texture (PVA) (2.2 mmol(c) dm(-3) K). A completely randomized design in a factorial arrangement 6 x 2 (six K rates and two soils) was used, with four replications. The K rates used were: 0, 25, 50, 100, 150 and 200 mg kg(-1) K. Potassium fertilization increased K content in soil and shoots. Dry matter production was increased with the K addition. However, in the PVA, this occurred only in the second cut. In LV, potassium fertilization increased N concentration in alfalfa shoots in both cuts. Plants with K concentration around 10 g kg(-1) had typical symptoms of this nutrient deficiency. The K critical levels of K in soil and shoots were 1.8 mmolc dm(-3) and 16.7 g kg(-1), respectively.