An abiotic typology and reference conditions for nutrients and chlorophyll-a in subtropical reservoirs (São Paulo State,Brazil)

Environmental Science and Pollution Research - The establishment of reference conditions and typology are two important steps in water resources management. The reference conditions enable the...     

Recycled lightweight concrete made from footwear industry waste and CDW

In this paper two types of recycled aggregate, originated from construction and demolition waste (CDW) and ethylene vinyl acetate (EVA) waste, were used in the production of concrete. The EVA waste results from cutting off the EVA expanded sheets used to produce insoles and innersoles of shoes in the footwear industry. The goal of this study was to evaluate the influence of the use of these recycled aggregates as replacements of the natural coarse aggregate, upon density, compressive strength, tensile splitting strength and flexural behavior of recycled concrete. The experimental program was developed with three w/c ratios: 0.49, 0.63 and 0.82. Fifteen mixtures were produced with different aggregate substitution rates (0%, 50% EVA, 50% CDW, 25% CDW–25% EVA and 50% CDW–50% EVA), by volume. The results showed that it is possible to use the EVA waste and CDW to produce lightweight concrete having semi-structural properties.     

Nonpoint sources of volatile organic compounds in urban areas-relative importance of land surfaces and air

Volatile organic compounds (VOCs) commonly detected in urban waters across the United States include gasoline-related compounds (e.g. toluene, xylene) and chlorinated compounds (e.g. chloroform, tetrachloroethane [PCE], trichloroethene [TCE]). Statistical analysis of observational data and results of modeling the partitioning of VOCs between air and water suggest that urban land surfaces are the primary nonpoint source of most VOCs. Urban air is a secondary nonpoint source, but could be an important source of the gasoline oxygenate methyl-tert butyl ether (MTBE). Surface waters in urban areas would most effectively be protected by controlling land-surface sources.     

PARAMETER IDENTIFICATION IN A TWO‐MULTIPLIER SEDIMENT YIELD MODEL1

ABSTRACT: A process based, distributed runoff erosion model (KINEROS2) was used to examine problems of parameter identification of sediment entrainment equations for small watersheds. Two multipliers were used to reflect the distributed nature of the sediment entrainment parameters: one multiplier for a raindrop induced entrainment parameter, and one multiplier for a flow induced entrainment parameter. The study was conducted in three parts. First, parameter identification was studied for simulated error free data sets where the parameter values were known. Second, the number of data points in the simulated sedigraphs was reduced to reflect the effect of temporal sampling frequency on parameter identification. Finally, event data from a small range‐land watershed were used to examine parameter identifiability when the parameter values are unknown. Results demonstrated that whereas unique multiplier values can be obtained for simulated error free data, unique parameter values could not be obtained for some event data. Unique multiplier values for raindrop induced entrainment and flow induced entrainment were found for events with greater than a two‐year return period (～25 mm) that also had at least 10 mm of rain in ten minutes. It was also found that the three‐minute sampling frequency used for the sediment sampler might be inadequate to identify parameters in some cases.     

Digeorge syndrome with total monosomy 22 diagnosed prenatally

A case of monosomy 22 diagnosed prenatally is reported. During pregnancy, ultrasonic observations already revealed several cardiac malformations of the fetus in the 25th week. Following counselling, the pregnancy was terminated. Fetal autopsy revealed several abnormalities associated with DiGeorge syndrome.     

Prenatal diagnosis of tetrasomy 21

Amniocentesis and prenatal diagnosis were done for late maternal age and an abnormality consistent with Tetrasomy 21 (47,XX,+t(21;21)) was found in every cell examined of the initial amniotic fluid. Clinical examination revealed a fetus with many of the signs of Down Syndrome and pathological examination revealed gross abnormalities of the internal structures. Follow-up tissues showed mosaic Tetrasomy 21.     

Bioconcentration of trichlorfon insecticide in pacu (Piaractus mesopotamicus)

Pacu (Piaractus mesopotamicus) is one of the most representative fish species of Brazilian fish culture, produced in most Brazilian States due to its importance for food diet and sport fishery. This research work investigated the bioconcentration of trichlorfon [phosphonic acid, (2,2,2-trichloro-1-hydroxyethyl)-dimethyl ester] insecticide in pacu under fish ponds culture conditions and a first-order kinetic insecticide dissipation in the water. Trichlorfon was applied at a rate of 4.62 x 10(4) mg to each of three nurseries containing 4.2 x 10(5)l of water. The fish ponds were built on the soil and supported 60 young pacus fishes. The concentrations of trichlorfon fitted to an equivalent non-linear kinetic type model, allows estimate the values of trichlorfon concentration in the water and fishes. These estimations together with the bioconcentration factor determined in the fishes, allowed establishing theoretical reference limit values for human consumption of fishes produced under cultivation systems with trichlorfon. This information will contribute to enlarge the database on pesticide use in Brazilian commercial fish farming, especially about the use of trichlorfon as chemotherapy for the control of fish ectoparasites.     

Numerical simulation of sand dune erosion

Erosion of sand or other granular material is a subject of utmost importance in several fields of practical interest, including industrial processes or environmental issues. Resulting from intricate interaction between the incident flow field and localized body forces responsible for the granular material cohesion, erosion is a particularly complex phenomenon. The present work addresses this problem, proposing a numerical method to compute the time evolution of a sand dune subjected to aeolian erosion, along with the associated entrainment and deposition fluxes. Turbulent fluid flow is computed through a three-dimensional Navier-Stokes solver based on a generalized coordinate system. A Lagrangian approach is adopted for tracking the trajectories of particles entrained in the saltation regime, thus allowing prediction of the corresponding deposition locations. Different models for saltation fluxes are tested, along with several formulations for the creeping-to-saltation flux ratio, creeping threshold and creeping distance. Comparison with results from wind tunnel experiments is very encouraging, stressing the relative importance of creeping in the erosion process for the presently studied conditions.