Aspectos quantitativos e qualitativos das águas da Bacia Experimental do Rio Pardo - Região de Botucatu, SP

Pós-graduação em Agronomia (Energia na Agricultura) - FCA

Avaliação da qualidade da água do rio Poti na cidade de Teresina, Piauí

Pós-graduação em Geografia - IGCE

Influência da bacia hidrográfica e características espaço-temporais de variáveis limnológicas sobre reservatórios no Rio Jacuí - RS

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Copper(II) and Nickel (II) Complexation Capacity of Dissolved Organic Matter from Rivers of Agricultural and Urban Areas in the State of Sao Paulo

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

Rn-222, Rn-220 and other dissolved gases in mineral waters of southeast Brazil

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

Effect of Water Exchange and Mechanical Aeration on Grow-out of the Amazon River Prawn in Ponds

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

A local-global scheme for tracking crack path in three-dimensional solids

This paper aims to contribute to the three-dimensional generalization of numerical prediction of crack propagation through the formulation of finite elements with embedded discontinuities. The analysis of crack propagation in two-dimensional problems yields lines of discontinuity that can be tracked in a relatively simple way through the sequential construction of straight line segments oriented according to the direction of failure within each finite element in the solid. In three-dimensional analysis, the construction of the discontinuity path is more complex because it requires the creation of plane surfaces within each element, which must be continuous between the elements. In the method proposed by Chaves (2003) the crack is determined by solving a problem analogous to the heat conduction problem, established from local failure orientations, based on the stress state of the mechanical problem. To minimize the computational effort, in this paper a new strategy is proposed whereby the analysis for tracking the discontinuity path is restricted to the domain formed by some elements near the crack surface that develops along the loading process. The proposed methodology is validated by performing three-dimensional analyses of basic problems of experimental fractures and comparing their results with those reported in the literature.

Avaliação espaço-temporal da qualidade da água e simulação de autodepuração na bacia hidrográfica do córrego São Simão, SP

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

The influence of floc size and hydraulic detention time on the performance of a dissolved air flotation (DAF) pilot unit in the light of a mathematical model

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

Effects of litter manipulation in a tropical Eucalyptus plantation on leaching of mineral nutrients, dissolved organic nitrogen and dissolved organic carbon

Although many studies have shown that soil solution chemistry can be a reliable indicator of biogeochemical cycling in forest ecosystems, the effects of litter manipulations on the fluxes of dissolved elements in gravitational soil solutions have rarely been investigated. We estimated the fluxes of NH4-N, NO3-N, K, Ca, Mg, Na, Cl, dissolved organic nitrogen (DON) and dissolved organic carbon (DOC) over the first two years after re-planting Eucalyptus trees in the coastal area of Congo. Two treatments were replicated in two blocks after clear-cutting 7-year-old stands: in treatment R, all the litter above the mineral soil was removed before planting, and in a double slash (DS) treatment, the amount of harvest residues was doubled. The soil solutions were sampled down to a depth of 4 m and the water fluxes were estimated using the Hydrus 1D model parameterized from soil moisture measurements in 4 plots. Isotopic and spectroscopic analytical techniques were used to assess the changes in dissolved organic matter (DOM) properties throughout the transfer in the soil. The first year after planting, the fluxes of NH4-N, K, Ca, Mg, Na, Cl and DOC in the topsoil of the DS treatment were 2-5 times higher than in R, which showed that litter was a major source of dissolved nutrients. Nutrient fluxes in gravitational solutions decreased sharply in the second year after planting, irrespective of the soil depth, as a result of intense nutrient uptake by Eucalyptus trees. Losses of dissolved nutrients were noticeably low in these Eucalyptus plantations despite a low cation exchange capacity, a coarse soil texture and large amounts of harvest residues left on-site at the clear cut in the DS treatment. All together, these results clarified the strong effect of litter manipulation observed on eucalypt growth in Congolese sandy soils. DOM fluxes, as well as changes in delta C-13, C:N and aromaticity of DOM throughout the soil profile showed that the organic compounds produced in the litter layer were mainly consumed by microorganisms or retained in the topsoil. Below a depth of 15 cm, most of the DOC and the DON originated from the first 2 cm of the soil and the exchanges between soil solutions and soil organic matter were low. (C) 2014 Elsevier B.V. All rights reserved.

Dissolved uranium, radium and radon evolution in the Continental Intercalaire aquifer, Algeria and Tunisia

Natural, dissolved U-238-series radionuclides (U, Ra-226, Rn-222) and activity ratios (A.R.s: U-234/U-238; Ra-228/Ra-226) in Continental Intercalaire (Cl) groundwaters and limited samples from the overlying Complexe Terminal (CT) aquifers of Algeria and Tunisia are discussed alongside core measurements for U/Th (and K) in the contexts of radiological water quality, geochemical controls in the aquifer, and water residence times. A redox barrier is characterised downgradient in the Algerian Cl for which a trend of increasing U-234/U-238 A.R.s with decreasing U-contents due to recoil-dominated U-234 solution under reducing conditions allows residence time modelling similar to 500 ka for the highest enhanced A.R. = 3.17. Geochemical modelling therefore identifies waters towards the centre of the Grand Erg Oriental basin as palaeowaters in line with reported C-14 and Cl-36 ages. A similar U-234/U-238 trend is evidenced in a few of the Tunisian CI waters. The paleoage status of these waters is affirmed by both noble gas recharge temperatures and simple modelling of dissolved, radiogenic He-4-contents both for sampled Algerian and Tunisian CI and CT waters. For the regions studied these waters therefore should be regarded as "fossil" waters and treated effectively as a non-renewable resource. (C) 2014 The Authors. Published by Elsevier Ltd.

Differential environmental impacts on small and medium size rivers from center of São Paulo State, Brazil, and regional management perspectives

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Tratamento de águas oleosas oriundas do processo de produção de óleo de dendê utilizando a flotação por ar dissolvido

This study was developed to evaluate the performance of different coagulant and pH dosages by applying the use of Dissolved Air Flotation (FAD) to enable its use in effluent treatment of the extraction process of palm oil. The study was developed in the laboratory, where studies about emulsions stability were made for the production of a synthetic effluent which best suit the characteristics of raw effluent. The synthetic water that would be used in the tests of FAD was produced, once the stability and characterization which best approached the raw wastewater was obtained. Trials tested three coagulant doses, combined with various pH ranges and five upward velocities (Va), finding an optimal range of this combination. Some operating parameters such as time and gradient of rapid mixing (20 s / 1000 s-1), time and gradient flotation (15 min / 60 s-1), chamber pressure saturation (450 kPa) and recirculation rate (20%) were set. In this way, samples were collected for analysis of the removal of turbidity parameters, suspended solids and oils and greases. This one is obtained by a correlation turbidity x oils and greases, referring to the previous analysis. The degree of removal obtained were 73,97% for turbidity, 51,4% for total suspended solids and 86,2% for oils and greases. Removal rates may be increased in later studies, by ranging the velocity gradient and flocculation parameters and the recirculation ratio, and by using lower flotation speeds to these effluent characteristics.

Construction of a chamber for in situ monitoring of the drying process of gels and porous solids

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

Estimation of Submerged Aquatic Vegetation Height and Distribution in Nova Avanhandava Reservoir (São Paulo State, Brazil) Using Bio-Optical Modeling

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)