Atividade radicular da soja: definição de um método

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

Avaliação do sistema radicular da cana-de-açúcar por diferentes métodos

Para decidir qual método de avaliação do sistema radicular, é necessário ponderar sobre os objetivos do trabalho, a cultura em questão e as condições em que ela se desenvolve. O estudo de raízes é muito importante para a compreensão dos diversos fenômenos de crescimento e desenvolvimento da parte aérea, mas exige procedimentos extremamente criteriosos, pois, além de ser trabalhoso, seus resultados são influenciados pela variabilidade físico-química do solo. Objetivou-se, com esta pesquisa, comparar os resultados de cinco métodos de avaliação do sistema radicular, em duas variedades de cana-de-açúcar, em quatro profundidades e em dois sistemas de colheita: mecanizada de cana crua e manual de cana queimada. Foram comparados ao método de avaliação por extração de monólitos e pesagem de massa de raízes secas outros quatro métodos: monólito com medição de comprimento, trado com pesagem de massa seca, perfil com medição de comprimento por meio de imagens digitais e perfil com contagem do número de raízes. Constatou-se que regressões lineares expressaram adequadamente a relação entre os métodos estudados, exceto quando foi utilizado o trado. Os métodos de perfil foram os mais adequados para detectar diferenças entre tratamentos.

Characterization of tin oxide based sol-gel coatings on borosilicate glasses by X-ray reflectivity

The X-ray reflectivity technique was applied in the study of tin oxide films deposited by sol-gel dip-coating on borosilicate glasses. The influence of the withdrawal speed and temperature of thermal treatment on the film structure was analyzed. We have compared the thermal evolution of the density and the shrinkage of the films with these properties measured for the monolithic xerogel by helium picnometry and thermomechanical analysis. In agreement with the Landau-Levich model, the layer thickness increases by increasing the withdrawal speed. Nevertheless, it decreases with the increase of the thermal treatment temperature, due to the densification process. The values of apparent density are smaller than the skeletal density, which shows that the films are porous. The comparison between the film and the monolith indicates that shrinkage during firing is anisotropic, occurring essentially perpendicular to the coating surface.

Digital image analysis of root distribution towards improved irrigation water and soil management: Grapevine and date palm study cases

It is presented two study cases about the approach in root analysis at field and laboratory conditions based on digital image analysis. Grapevine (Vitis vinifera L.) and date palm (Phoenix dactylifera L.) root systems were analyzed by both the monolith and trench wall method aided by digital image analysis. Correlation between root parameters and their fractional distribution over the soil profile were obtained, as well as the root diameter estimation. Results have shown the feasibility of digital image analysis for evaluation of root distribution.

A produção do espaço sagrado em Quixadá - Ceará: estudo das inter-relações econômicas, socioculturais e o lugar

Pós-graduação em Geografia - IGCE

Pore structure and column efficiency of silica monoliths in high performance liquid chromatography (HPLC)

Five different methods were critically examined to characterize the pore structure of the silica monoliths. The mesopore characterization was performed using: a) the classical BJH method of nitrogen sorption data, which showed overestimated values in the mesopore distribution and was improved by using the NLDFT method, b) the ISEC method implementing the PPM and PNM models, which were especially developed for monolithic silicas, that contrary to the particulate supports, demonstrate the two inflection points in the ISEC curve, enabling the calculation of pore connectivity, a measure for the mass transfer kinetics in the mesopore network, c) the mercury porosimetry using a new recommended mercury contact angle values. rnThe results of the characterization of mesopores of monolithic silica columns by the three methods indicated that all methods were useful with respect to the pore size distribution by volume, but only the ISEC method with implemented PPM and PNM models gave the average pore size and distribution based on the number average and the pore connectivity values.rnThe characterization of the flow-through pore was performed by two different methods: a) the mercury porosimetry, which was used not only for average flow-through pore value estimation, but also the assessment of entrapment. It was found that the mass transfer from the flow-through pores to mesopores was not hindered in case of small sized flow-through pores with a narrow distribution, b) the liquid penetration where the average flow-through pore values were obtained via existing equations and improved by the additional methods developed according to Hagen-Poiseuille rules. The result was that not the flow-through pore size influences the column bock pressure, but the surface area to volume ratio of silica skeleton is most decisive. Thus the monolith with lowest ratio values will be the most permeable. rnThe flow-through pore characterization results obtained by mercury porosimetry and liquid permeability were compared with the ones from imaging and image analysis. All named methods enable a reliable characterization of the flow-through pore diameters for the monolithic silica columns, but special care should be taken about the chosen theoretical model.rnThe measured pore characterization parameters were then linked with the mass transfer properties of monolithic silica columns. As indicated by the ISEC results, no restrictions in mass transfer resistance were noticed in mesopores due to their high connectivity. The mercury porosimetry results also gave evidence that no restrictions occur for mass transfer from flow-through pores to mesopores in the small scaled silica monoliths with narrow distribution. rnThe prediction of the optimum regimes of the pore structural parameters for the given target parameters in HPLC separations was performed. It was found that a low mass transfer resistance in the mesopore volume is achieved when the nominal diameter of the number average size distribution of the mesopores is appr. an order of magnitude larger that the molecular radius of the analyte. The effective diffusion coefficient of an analyte molecule in the mesopore volume is strongly dependent on the value of the nominal pore diameter of the number averaged pore size distribution. The mesopore size has to be adapted to the molecular size of the analyte, in particular for peptides and proteins. rnThe study on flow-through pores of silica monoliths demonstrated that the surface to volume of the skeletons ratio and external porosity are decisive for the column efficiency. The latter is independent from the flow-through pore diameter. The flow-through pore characteristics by direct and indirect approaches were assessed and theoretical column efficiency curves were derived. The study showed that next to the surface to volume ratio, the total porosity and its distribution of the flow-through pores and mesopores have a substantial effect on the column plate number, especially as the extent of adsorption increases. The column efficiency is increasing with decreasing flow through pore diameter, decreasing with external porosity, and increasing with total porosity. Though this tendency has a limit due to heterogeneity of the studied monolithic samples. We found that the maximum efficiency of the studied monolithic research columns could be reached at a skeleton diameter of ~ 0.5 µm. Furthermore when the intention is to maximize the column efficiency, more homogeneous monoliths should be prepared.rn

Innovative processes for syngas production

The research of new advanced processes for syngas production is a part of a European project for the production of a new Gas to Liquid Process (NextGTL). The crucial points in the production of GTL process are the energy required for the air separation used in autothermal reforming or the heat required for steam reforming and the efficiency in carbon utilization. Therefore a new multistep oxy-reforming process scheme was developed at lower temperature with intermediate H2 membrane separation to improve the crucial parameter. The process is characterized by a S/C of 0.7 and O2/C of 0.21 having a smoothed temperature profile in which kinetic regime is easily obtained. Active catalysts for low temperature oxy-reforming process have been studied working at low pressure to discriminate among the catalyst and at high pressure to prove it on industrial condition. It allows the selection of the Rh as active phase among single and bimetallic VIII group metal. The study of the matrix composition and thermal treatment has been carried out on Rh-Mg/Al hydrotalcite selected as reference catalyst. The research to optimize the catalyst lead to enhanced performances through the identification of a limitation of the Rh reduction from the oxides matrix as key point to increase the Rh performances. The Rh loading have been studied to allow the catalyst scale up for pilot process in Chieti in a shape of Rh-HT on honeycomb ceramic material. The developed catalyst has enhanced methane conversion in a inch diameter monolith reactor if compared with the semi-industrial catalyst chosen in the project as the best reference.

Modeling of diesel particulate filter filtration and regeneration for transient driving schedules

Due to their high thermal efficiency, diesel engines have excellent fuel economy and have been widely used as a power source for many vehicles. Diesel engines emit less greenhouse gases (carbon dioxide) compared with gasoline engines. However, diesel engines emit large amounts of particulate matter (PM) which can imperil human health. The best way to reduce the particulate matter is by using the Diesel Particulate Filter (DPF) system which consists of a wall-flow monolith which can trap particulates, and the DPF can be periodically regenerated to remove the collected particulates. The estimation of the PM mass accumulated in the DPF and total pressure drop across the filter are very important in order to determine when to carry out the active regeneration for the DPF. In this project, by developing a filtration model and a pressure drop model, we can estimate the PM mass and the total pressure drop, then, these two models can be linked with a regeneration model which has been developed previously to predict when to regenerate the filter. There results of this project were: 1 Reproduce a filtration model and simulate the processes of filtration. By studying the deep bed filtration and cake filtration, stages and quantity of mass accumulated in the DPF can be estimated. It was found that the filtration efficiency increases faster during the deep-bed filtration than that during the cake filtration. A “unit collector” theory was used in our filtration model which can explain the mechanism of the filtration very well. 2 Perform a parametric study on the pressure drop model for changes in engine exhaust flow rate, deposit layer thickness, and inlet temperature. It was found that there are five primary variables impacting the pressure drop in the DPF which are temperature gradient along the channel, deposit layer thickness, deposit layer permeability, wall thickness, and wall permeability. 3 Link the filtration model and the pressure drop model with the regeneration model to determine the time to carry out the regeneration of the DPF. It was found that the regeneration should be initiated when the cake layer is at a certain thickness, since a cake layer with either too big or too small an amount of particulates will need more thermal energy to reach a higher regeneration efficiency. 4 Formulate diesel particulate trap regeneration strategies for real world driving conditions to find out the best desirable conditions for DPF regeneration. It was found that the regeneration should be initiated when the vehicle’s speed is high and during which there should not be any stops from the vehicle. Moreover, the regeneration duration is about 120 seconds and the inlet temperature for the regeneration is 710K.

Measurements of a water potential and water content in unsaturated crystalline rock

A water desaturation zone develops around a tunnel in water-saturated rock when the evaporative water loss at the rock surface is larger than the water flow from the surrounding saturated region of restricted permeability. We describe the methods with which such water desaturation processes in rock materials can be quantified. The water retention characteristic theta(psi) of crystalline rock samples was determined with a pressure membrane apparatus. The negative water potential, identical to the capillary pressure, psi, below the tensiometric range (psi < -0.1 MPa) can be measured with thermocouple psychrometers (TP), and the volumetric water contents, theta, by means of time domain reflectometry (TDR). These standard methods were adapted for measuring the water status in a macroscopically unfissured granodiorite with a total porosity of approximately 0.01. The measured water retention curve of granodiorite samples from the Grimsel test site (central Switzerland) exhibits a shape which is typical for bimodal pore size distributions. The measured bimodality is probably an artifact of a large surface ratio of solid/voids. The thermocouples were installed without a metallic screen using the cavity drilled into the granodiorite as a measuring chamber. The water potentials observed in a cylindrical granodiorite monolith ranged between -0.1 and -3.0 MPa; those near the wall in a ventilated tunnel between -0.1 and -2.2 MPa. Two types of three-rod TDR Probes were used, one as a depth probe inserted into the rock, the other as a surface probe using three copper stripes attached to the surface for detecting water content changes in the rock-to-air boundary. The TDR signal was smoothed with a low-pass filter, and the signal length determined based on the first derivative of the trace. Despite the low porosity of crystalline rock these standard methods are applicable to describe the unsaturated zone in solid rock and may also be used in other consolidated materials such as concrete.

Report on 2010-2013 Excavations at Horvat Kur, Galilee

Four seasons of excavations at Horvat Kur in the Galilee (250570/754485) have exposed the remains of a broadhouse synagogue from the Byzantine period. The building was entered through a portico on the west or a doorway on the south. The fill beneath the portico included the discarded remains of a once colored mosaic as well as more than 1000 coins. A low bench of basalt stones (some of which were plastered) runs along the interior walls, interrupted only by a stone bemah in the center of the southern wall. The synagogue is thus oriented toward Jerusalem. Near the bemah, an ornamented limestone seat was found in situ atop the bench. The building underwent several changes and repairs in the course of its lifespan. On either side of the bemah, north-south rows of columns rested on stylobate. A basalt stone table was found in re-use in the eastern stylobate. Nicknamed “the Horvat Kur stone,” this monolith features geometric figures on three sides and figurative representations on one side. Its original function is as yet subject of research. A narrow test-trench into the sediment of a cistern located outside the northern wall of the synagogue has produced nearly thirty intact vessels of the early Byzantine period, mostly cooking pots and water jars. In addition a dense sequence of pollen samples has been taken. Preliminary interpretation of these finds indicates that the Horvat Kur synagogue illustrates Byzantine synagogue construction, decoration, and use in the setting of a Galilean village of modest economic circumstances.

Family Preservation Journal, 1998, Volume 3, Issue 2. (Entire issue)

Entire issue (large pdf file) Articles include: Getting to Know You: Psychoeducational Groups to Counter Social Isolation of Neglectful Mothers. Marianne Berry Intensive Family Preservation in Children's Mental Health: Predictors of Placement. Cathryn C. Potter An Innovative Family Preservation Program in an African American Community: Longitudinal Analysis. Patricia Ciliberti Chipping Away at the Monolith: Dispelling the Myth of Father Noninvolvement in Children's Early Literacy Development. Robert W. Ortiz

Accumulation rates and predominant atmospheric sources of natural and anthropogenic Hg and Pb on the Faroe Islands

A monolith representing 5420 14C yr of peat accumulation was collected from a blanket bog at Myrarnar, Faroe Islands. The maximum Hg concentration (498 ng/g at a depth of 4.5 cm) coincides with the maximum concentration of anthropogenic Pb (111 μg/g). Age dating of recent peat accumulation using 210Pb (CRS model) shows that the maxima in Hg and Pb concentrations occur at AD 1954 ± 2. These results, combined with the isotopic composition of Pb in that sample (206Pb/207Pb = 1.1720 ± 0.0017), suggest that coal burning was the dominant source of both elements. From the onset of peat accumulation (ca. 4286 BC) until AD 1385, the ratios Hg/Br and Hg/Se were constant (2.2 ± 0.5 × 10-4 and 8.5 ± 1.8 × 10-3, respectively). Since then, Hg/Br and Hg/Se values have increased, also reaching their maxima in AD 1954. The age date of the maximum concentrations of anthropogenic Hg and Pb in the Faroe Islands is consistent with a previous study of peat cores from Greenland and Denmark (dated using the atmospheric bomb pulse curve of 14C), which showed maximum concentrations in AD 1953. The average rate of atmospheric Hg accumulation from 1520 BC to AD 1385 was 1.27 ± 0.38 μg/m2/yr. The Br and Se concentrations and the background Hg/Br and Hg/Se ratios were used to calculate the average rate of natural Hg accumulation for the same period, 1.32 ± 0.36 μg/m2/yr and 1.34 ± 0.29 μg/m2/yr, respectively. These fluxes are similar to the preanthropogenic rates obtained using peat cores from Switzerland, southern Greenland, southern Ontario, Canada, and the northeastern United States. Episodic volcanic emissions and the continual supply of marine aerosols to the Faroe Islands, therefore, have not contributed significantly to the Hg inventory or the Hg accumulation rates, relative to these other areas. The maximum rate of Hg accumulation was 34 μg/m2/yr. The greatest fluxes of anthropogenic Hg accumulation calculated using Br and Se, respectively, were 26 and 31 μg/m2/yr. The rate of atmospheric Hg accumulation in 1998 (16 μg/m2/yr) is comparable to the values recently obtained by atmospheric transport modeling for Denmark, the Faroe Islands, and Greenland.

Relationships between soil nitrate desorbed from anion-exchange membranes, canopy reflectance and nitrate leaching losses from cool-season lawn turf.

Nutrient leaching studies are expensive and require expertise in water collection and analyses. Less expensive or easier methods that estimate leaching losses would be desirable. The objective of this study was to determine if anion-exchange membranes (AEMs) and reflectance meters could predict nitrate (NO3-N) leaching losses from a cool-season lawn turf. A two-year field study used an established 90% Kentucky bluegrass (Poa pratensis L.)-10% creeping red fescue (Festuca rubra L.) turf that received 0 to 98 kg N ha-1 month-1, from May through November. Soil monolith lysimeters collected leachate that was analyzed for NO3-N concentration. Soil NO3-N was estimated with AEMs. Spectral reflectance measurements of the turf were obtained with chlorophyll and chroma meters. No significant (p > 0.05) increase in percolate flow-weighted NO3-N concentration (FWC) or mass loss occurred when AEM desorbed soil NO3-N was below 0.84 µg cm-2 d-1. A linear increase in FWC and mass loss (p < 0.0001) occurred, however, when AEM soil NO3-N was above this value. The maximum contaminant level (MCL) for drinking water (10 mg L-1 NO3-N) was reached with an AEM soil NO3-N value of 1.6 µg cm-2 d-1. Maximum meter readings were obtained when AEM soil NO3 N reached or exceeded 2.3 µg cm-2 d-1. As chlorophyll index and hue angle (greenness) increased, there was an increased probability of exceeding the NO3-N MCL. These data suggest that AEMs and reflectance meters can serve as tools to predict NO3-N leaching losses from cool-season lawn turf, and to provide objective guides for N fertilization.

Fall Fertilization Timing Effects on Nitrate Leaching and Turfgrass Color and Growth

Fall season fertilization is a widely recommended practice for turfgrass. Fertilizer applied in the fall, however, may be subject to substantial leaching losses. A field study was conducted in Connecticut to determine the timing effects of fall fertilization on nitrate N (NO3-N) leaching, turf color, shoot density, and root mass of a 90% Kentucky bluegrass (Poa pratensis L.), 10% creeping red fescue (Festuca rubra L.) lawn. Treatments consisted of the date of fall fertilization: 15 September, 15 October, 15 November, 15 December, or control which received no fall fertilizer. Percolate water was collected weekly with soil monolith lysimeters. Mean log10 NO3-N concentrations in percolate were higher for fall fertilized treatments than for the control. Mean NO3-N mass collected in percolate water was linearly related to the date of fertilizer application, with higher NO3-N loss for later application dates. Applying fall fertilizer improved turf color and density but there were no differences in color or density among applications made between 15 October and 15 December. These findings suggest that the current recommendation of applying N in mid- to late November in southern New England may not be compatible with water quality goals.