987 resultados para root system
Resumo:
Recently, the development of industrial processes brought on the outbreak of technologically complex systems. This development generated the necessity of research relative to the mathematical techniques that have the capacity to deal with project complexities and validation. Fuzzy models have been receiving particular attention in the area of nonlinear systems identification and analysis due to it is capacity to approximate nonlinear behavior and deal with uncertainty. A fuzzy rule-based model suitable for the approximation of many systems and functions is the Takagi-Sugeno (TS) fuzzy model. IS fuzzy models are nonlinear systems described by a set of if then rules which gives local linear representations of an underlying system. Such models can approximate a wide class of nonlinear systems. In this paper a performance analysis of a system based on IS fuzzy inference system for the calibration of electronic compass devices is considered. The contribution of the evaluated IS fuzzy inference system is to reduce the error obtained in data acquisition from a digital electronic compass. For the reliable operation of the TS fuzzy inference system, adequate error measurements must be taken. The error noise must be filtered before the application of the IS fuzzy inference system. The proposed method demonstrated an effectiveness of 57% at reducing the total error based on considered tests. (C) 2011 Elsevier Ltd. All rights reserved.
Resumo:
A new assessment of the aluminum corner of the quaternary Al-Fe-Mn-Si system has been made that extends beyond the COST-507 database. This assessment makes use of a recent, improved description of the ternary Al-Fe-Si system. In the present work, modeling of the Al-rich corner of the quaternary Al-Fe-Mn-Si system has been carried out by introducing Fe solubility into the so-called alpha-AlMnSi and beta-AlMnSi phases of the Al-Mn-Si system. A critical review of the data available on the quaternary system is presented and used for the extension of the description of these ternary phases into the quaternary Al-Fe-Mn-Si.
Resumo:
The thermodynamic assessment of an Al(2)O(3)-MnO pseudo-binary system has been carried out with the use of an ionic model. The use of the electro-neutrality principles in addition to the constitutive relations, between site fractions of the species on each sub-lattice, the thermodynamics descriptions of each solid phase has been determined to make possible the solubility description. Based on the thermodynamics descriptions of each phase in addition to thermo-chemical data obtained from the literature, the Gibbs energy functions were optimized for each phase of the Al(2)O(3)-MnO system with the support of PARROT(R) module from ThemoCalc(R) package. A thermodynamic database was obtained, in agreement with the thermo-chemical data extracted from the literature, to describe the Al(2)O(3)-MnO system including the solubility description of solid phases. (C) 2009 Elsevier Ltd. All rights reserved.
Resumo:
A thermodynamic information system for diagnosis and prognosis of an existing power plant was developed. The system is based on an analytic approach that informs the current thermodynamic condition of all cycle components, as well as the improvement that can be obtained in the cycle performance by the elimination of the discovered anomalies. The effects induced by components anomalies and repairs in other components efficiency, which have proven to be one of the main drawbacks in the diagnosis and prognosis analyses, are taken into consideration owing to the use of performance curves and corrected performance curves together with the thermodynamic data collected from the distributed control system. The approach used to develop the system is explained, the system implementation in a real gas turbine cogeneration combined cycle is described and the results are discussed. (C) 2011 Elsevier Ltd. All rights reserved.
Resumo:
The objective of this research was to examine how various factors in Icelandic cod fishing can influence the quality of the raw material, using traceability systems to link these factors, and how transfer that knowledge and techniques to the Brazilian seafood industry. Data were collected in 2007 and analysed, to find a functional relationship between various quality factors. The analysis, showed, that there is a correlation between the number of parasites in the fillets and location of the fishing ground. It also showed that fishing ground and volume in haul can influence gaping, and that fillet yield differs between fishing grounds. These conclusions could only be drawn because of the ability to trace the fish from catch and all the way through processing. Recommendations drawn from this research to the Brazilian Competent Authority are to revise the countries fisheries legislation in order to enable the implementation of a traceability system that could be used as a tool to improve the quality of the raw material. (C) 2010 Elsevier Ltd. All rights reserved.
Resumo:
Underground systems of Asteraceac species from the Brazilian Cerrado. The aim or this study was to describe the underground systems structure, the origin of the shoot buds, and to identify the storage reserve of seven Asteraceae species in order to understand the adaptive strategies of these species in burned Cerrado areas and their higher frequency in the floristic Surveys for herbaceous and undershrub layers of this biome. The subterranean systems types-diffuse underground system, rhizophore, tuberous roots, and xylopodium-varied among the studied species, but all of them have high shoot bud-forming potential. Fructans of the inulin type were detected as storage substances. The presence of these characteristics on the underground systems Could explain the frequency of these species in the floristic surveys from the Brazilian Cerrado, in which Fire and seasonal drought are frequent. It is possible that the belowground bud banks in the Cerrado biome are as important as demonstrated in North American prairies where fire is also frequent. However, in the Cerrado, as demonstrated here, there are types of underground systems other than rhizomes that are usually described in the prairie. Understanding the anatomical features of these plants is one of the steps to appropriate conservation management of these species in the Cerrado.
Resumo:
The leaders` organizations of several different sectors have as characteristic to measure their own performance in a systematic way. However, this concept is still unusual in agricultural enterprises, including the mechanization sector. Mechanization has an important role on the production costs and to know its performance is a key factor for the agricultural enterprise success. This work was generated by the importance that measurement of performance has for the management and the mechanization impact on the production costs. Its aim is to propose an integrated performance measurement system to give support to agricultural management. The methodology was divided in two steps: adjustment of a conceptual model based on Balanced Score Card - BSC; application of the model in a study case at sugar cane mill. The adjustment and the application of the conceptual model allowed to obtain the performance index in a systematic way, that are associated to: costs and deadline ( traditionally used); control and improvement on the quality of operations and support process; environmental preservation; safety; health; employees satisfaction; development of information systems. The adjusted model helped the development of the performance measurement system for the mechanized management systems and the index allows an integrated view of the enterprise, related to its strategic objectives.
Resumo:
Leaching is disadvantageous, both for economical and environmental reasons since it may decrease the ecosystem productivity and may also contribute to the contamination of surface and ground water. The objective of this paper was to quantify the loss of nitrogen and sulfur by leaching, at the depth of 0.9 m, in an Ultisol in Sao Paulo State (Brazil) with high permeability, Cultivated with sugarcane during the agricultural cycle of crop plant. The following ions were evaluated: nitrite, nitrate, ammonium, and sulfate. Calcium, magnesium, potassium, and phosphate were also evaluated at the same depth. The sugarcane was planted and fertilized in the furrows with 120 log ha(-1) of N-urea. In order to find out the fate of N-fertilizer, four microplots with (15)N-enriched fertilizer were installed. Input and output of the considered ions at the depth of 0.9 m were quantified from the flux density of water and the concentration of the elements in the soil solution at this soil depth: tensiometers, soil water retention curve and soil solution extractors were used for this quantification. The internal drainage was 205 mm of water, with a total loss of 18 kg ha(-1) of N and 10 kg ha(-1) of S. The percentage of N in the soil solution derived from the fertilizer (%NSSDF) was 1.34, resulting in only 25 g ha(-1) of N fertilizer loss by leaching during all agricultural cycle. Under the experimental conditions of this crop plant, that is, high demand of nutrients and high incorporation of crop residues, the leached N represented 15% of applied N and S leaching were not considerable; the higher amount of leached N was native nitrogen and a minor quantity from N fertilizer; and the leached amount of Ca, Mg, K and P did not exceed the applications performed in the crop by lime and fertilization. (C) 2009 Elsevier B.V. All rights reserved.
Resumo:
Hydrological models featuring root water uptake usually do not include compensation mechanisms such that reductions in uptake from dry layers are compensated by an increase in uptake from wetter layers. We developed a physically based root water uptake model with an implicit compensation mechanism. Based on an expression for the matric flux potential (M) as a function of the distance to the root, and assuming a depth-independent value of M at the root surface, uptake per layer is shown to be a function of layer bulk M, root surface M, and a weighting factor that depends on root length density and root radius. Actual transpiration can be calculated from the sum of layer uptake rates. The proposed reduction function (PRF) was built into the SWAP model, and predictions were compared to those made with the Feddes reduction function (FRF). Simulation results were tested against data from Canada (continuous spring wheat [(Triticum aestivum L.]) and Germany (spring wheat, winter barley [Hordeum vulgare L.], sugarbeet [Beta vulgaris L.], winter wheat rotation). For the Canadian data, the root mean square error of prediction (RMSEP) for water content in the upper soil layers was very similar for FRF and PRF; for the deeper layers, RMSEP was smaller for PRF. For the German data, RMSEP was lower for PRF in the upper layers and was similar for both models in the deeper layers. In conclusion, but dependent on the properties of the data sets available for testing,the incorporation of the new reduction function into SWAP was successful, providing new capabilities for simulating compensated root water uptake without increasing the number of input parameters or degrading model performance.
Resumo:
Time-domain reflectometry (TDR) is an important technique to obtain series of soil water content measurements in the field. Diode-segmented probes represent an improvement in TDR applicability, allowing measurements of the soil water content profile with a single probe. In this paper we explore an extensive soil water content dataset obtained by tensiometry and TDR from internal drainage experiments in two consecutive years in a tropical soil in Brazil. Comparisons between the variation patterns of the water content estimated by both methods exhibited evidences of deterioration of the TDR system during this two year period at field conditions. The results showed consistency in the variation pattern for the tensiometry data, whereas TDR estimates were inconsistent, with sensitivity decreasing over time. This suggests that difficulties may arise for the long-term use of this TDR system under tropical field conditions. (c) 2008 Elsevier B.V. All rights reserved.
Resumo:
The success in the adoption of peach integrated production (IP) was evaluated in small orchards of the Parana State. The importance of specific technical accompaniment; points of strangulating in adoption of technology and the classification of the areas to IP conformity were evaluated. The seasons 2005/2006 (without IP orientation) and 2006/2007 (with IP orientation) were compared considering 20 producers who were oriented monthly to attend the minimum requisites. The incidence of peach rust (Tranzschelia discolor) and of brown rot (Monilinia fructicola) in full bloom was evaluated in 2006/2007 and 2007/2008 seasons, as biological parameters to accompany the efficiency of system adoption. After the technical accompaniment in 2007/2008 season, the software APOIA-Novo Rural-PI (APOIA-PI) was applied to measure the conformity to IP in peach orchards. The conformity index of each orchard was compared to the minimum requisite to classify as IP (0.7). The major difficulties in register of field book were: pests monitoring; collect of climate data and the harvest evaluation. The technical accompaniment increased in 60% the conformity in use of field book. In 2007/2008 season, the brown rot incidence increased in some areas, caused by not following IP recommendations. The inadequate management caused the increment in pathogen inoculum, promoting the disease development in peach orchards. The APOIA-PI classified two orchards as good agricultural practices (GAP) (0.7 <= conformity index >= 0.4), two as integrated production (IP) (>= 0.7) and the other orchards had conformity index lower than 0.4.
Resumo:
Brown rot, caused by Monilinia fructicola, is the most widespread disease for organic peach production systems in Brazil. The objective of this study was to determine the favorable periods for latent infection by M. fructicola in organic systems. The field experiment was carried out during 2006, 2007 and 2008 using the cultivar Aurora. After thinning fruits were bagged using white paraffin bags, and the treatments were performed by removing the bags and exposing the fruit for four days to the natural infection during each of seven fruit stages from pit hardening to harvest. Throughout the entire growing season, the conidial density and the weather variables were measured and related to the disease incidence using multiple regression analyses. At the fourth day after harvest in each season, the cumulative disease incidence was assessed, and it ranged from 40 to 98%. The incidence of brown rot on fruit that were exposed during the embryo growing stage was lower than that of unbagged fruit throughout the entire season in 2006 and 2008. The relative humidity and the conidia density were significantly correlated to disease incidence. Based on our results, M. fructicola can infect peaches during any stage of fruit development, and control of the disease must be revised to account for organic peach production systems. (C) 2011 Elsevier Ltd. All rights reserved.
Resumo:
A comparative study between microsatellite and allozyme markers was conducted on the genetic structure and mating system in natural populations of Euterpe edulis Mart. Three cohorts, including seedlings, saplings, and adults, were examined in 4 populations using 10 allozyme loci and 10 microsatellite loci. As expected, microsatellite markers had a much higher degree of polymorphism than allozymes, but estimates of multilocus outcrossing rate ((t) over cap (m) = 1.00), as well as estimates of genetic structure (F(IS), G(ST)), were similar for the 2 sets of markers. Estimates of R(ST), for microsatellites, were higher than those of GST, but results of both statistics revealed a close agreement for the genetic structure of the species. This study provides support for the important conclusion that allozymes are still useful and reliable markers to estimate population genetic parameters. Effects of sample size on estimates from hypervariable loci are also discussed in this paper.
Resumo:
Iron (Fe) is an essential nutrient for plants, but it can generate oxidative stress at high concentrations. In this study, Coffea arabica L. cell suspension cultures were exposed to excess Fe (60 and 240 mu M) to investigate changes in the gene expression of ferritin and antioxidant enzymes. Iron content accumulated during cell growth, and Western blot analysis showed an increase of ferritin in cells treated with Fe. The expression of two ferritin genes retrieved from the Brazilian coffee EST database was studied. CaFER1, but not CaFER2, transcripts were induced by Fe exposure. Phylogenetic analysis revealed that CaFER1 is not similar to CaFER2 or to any ferritin that has been characterised in detail. The increase in ferritin gene expression was accompanied by an increase in the activity of antioxidant enzymes. Superoxide dismutase, guaiacol peroxidase, catalase, and glutathione reductase activities increased in cells grown in the presence of excess Fe, especially at 60 mu M, while the activity of glutathione S-transferase decreased. These data suggest that Fe induces oxidative stress in coffee cell suspension cultures and that ferritin participates in the antioxidant system to protect cells against oxidative damage. Thus, cellular Fe concentrations must be finely regulated to avoid cellular damage most likely caused by increased oxidative stress induced by Fe. However, transcriptional analyses indicate that ferritin genes are differentially controlled, as only CaFER1 expression was responsive to Fe treatment.
Resumo:
Experimental results obtained from a greenhouse trial with common bean (Phaseolus vulgaris L) plants performed to test model hypotheses regarding the onset of limiting hydraulic conditions and the shape of the transpiration reduction curve in the falling rate phase are presented. According to these hypotheses based on simulations with an upscaled single-root model, the matric flux potential at the onset of limiting hydraulic conditions is as a function of root length density and potential transpiration rate, while the relative transpiration in the falling rate phase equals the relative matric flux potential. Transpiration of bean plants in water stressed pots with four different soils was determined daily by weighing and compared to values obtained from non-stressed pots. This procedure allowed determining the onset of the falling rate phase and corresponding soil hydraulic conditions. At the onset of the falling rate phase, the value of matric flux potential M(I) showed to differ in order of magnitude from the model predicted value for three out of four soils. This difference between model and experiment can be explained by the heterogeneity of the root distribution which is not considered by the model. An empirical factor to deal with this heterogeneity should be included in the model to improve predictions. Comparing the predictions of relative transpiration in the falling rate phase using a linear shape with water content, pressure head or matric flux potential, the matric flux potential based reduction function, in agreement with the hypothesis, showed the best performance, while the pressure head based equation resulted in the highest deviations between observed and predicted values of relative transpiration rates. (C) 2010 Elsevier B.V. All rights reserved.