Stochastic simulation of time-series models combined with geostatistics to predict water-table scenarios in a Guarani Aquifer System outcrop area, Brazil

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

Theoretical study of MgO(001) surfaces: Pure, doped with Fe, Ca, and Al, and with and without adsorbed water

Ab initio calculations of large cluster models have been performed in order to study water adsorption at the five-fold coordinated adsorption site on pure Mg(001) and MgO(001) surfaces doped with Fe, Ca, and Al. The geometric parameters of the adsorbed water molecule have been optimized preparatory to analysis of binding energies, charge transfer, preferential sites of interaction, and bonding distances. We have used Mulliken population analysis methods in order to analyze charge distributions and the direction of charge transfer. We have also investigated energy gaps, HOMO energies, and SCF orbital energies as well as the acid-base properties of our cluster model. Numerical results are compared, where possible, with experiment and interpreted in the framework of various analytical models. (C) 2001 John Wiley & Sons, Inc.

Interaction between GIS and hydrologic model: a preliminary approach using ArcHydro Framework Data Model

In different regions of Brazil, population growth and economic development can degrade water quality, compromising watershed health and human supply. Because of its ability to combine spatial and temporal data in the same environment and to create water resources management (WRM) models, the Geographical Information System (GIS) is a powerful tool for managing water resources, preventing floods and estimating water supply. This paper discusses the integration between GIS and hydrological models and presents a case study relating to the upper section of the Paraíba do Sul Basin (Sao Paulo State portion), situated in the Southeast of Brazil. The case study presented in this paper has a database suitable for the basin's dimensions, including digitized topographic maps at a 50,000 scale. From an ArcGIS®/ArcHydro Framework Data Model, a geometric network was created to produce different raster products. This first grid derived from the digital elevation model grid (DEM) is the flow direction map followed by flow accumulation, stream and catchment maps. The next steps in this research are to include the different multipurpose reservoirs situated along the Paraíba do Sul River and to incorporate rainfall time series data in ArcHydro to build a hydrologic data model within a GIS environment in order to produce a comprehensive spatial-temporal model.