Influence of geology in the geochemistry signature of Itacolomi State Park waters,Minas Gerais-Brazil

In all geological scenarios, mineral water reactions will affect the water chemistry. As such, water resources in different rocks commonly involve different hydrogeological compartments. The aim of this work is to evaluate the influence of geology in the geochemistry signature of Itacolomi State Park waters. To do so, a survey of the geological units in the area was carried out, a geological/stratigraphic division was made, and its correlation with the main geological events was determined. Using the advantages of GIS, all the catchments were delimited. Based on this division, near 30 stream and lake segments were chosen for analyses. In each point, all physiochemical properties of the water were measured, and samples were collected to determine the concentrations of major and trace elements by ICP–OES. The dynamics of the Itacolomi State Park rock-soil and stream water solutions suggest that mixing of drainage waters from different bedrock and soil sources regulates stream water physical–chemical parameters and solute concentrations. The analytical data showed a clear correlation between the chemical compositions of the solute and the geological characteristics of the catchment. Units that are covered by iron oxide hardpan (Manso unit) and iron-banded formations (Custódio unit) show a large amount of soluble elements, including high values of Fe and Mn. On the other hand, the presence of high values of Al and K (Itacolomi unit) are a direct consequence of the presence of quartzite associated with low pH values.     

Hurricane flood risk assessment for the Yucatan and Campeche State coastal area

Natural Hazards - In this study, the first ever Sea, Lake, Overland Surges from Hurricanes (SLOSH) grid was built for the Yucatan Peninsula. The SLOSH model was used to simulate storm surges in the...     

Shaking table testing of an existing masonry building: assessment and improvement of the seismic performance

This paper aims to assess and improve the seismic performance of an existing masonry building with flexible floors, representative of a Portuguese building typology—‘gaioleiro’ buildings. The study involved seismic tests and dynamic identification tests of two models (nonstrengthened and strengthened) in the shaking table. Each model was subjected to several seismic tests with increasing amplitude. Before the first test and after each seismic test, the dynamic identification of the model was carried out, aiming at obtaining their seismic vulnerability curves based on a damage indicator obtained from the decrease of the frequencies of the modes. In the strengthened model, steel elements were used to improve the connection between walls and floors, together with ties in the upper stories. The results show that adopted strengthening technique is effective for reducing the seismic vulnerability of ‘gaioleiro’ buildings, namely for improving the out‐of‐plane behavior of the facades. Copyright © 2013 John Wiley & Sons, Ltd.     

Tropical Deforestation and the Kyoto Protocol

The current annual rates of tropical deforestation from Brazil and Indonesia alone would equal four-fifths of the emissions reductions gained by implementing the Kyoto Protocol in its first commitment period, jeopardizing the goal of Protocol to avoid “dangerous anthropogenic interference” with the climate system. We propose the novel concept of “compensated reduction”, whereby countries that elect to reduce national level deforestation to below a previously determined historical level would receive post facto compensation, and commit to stabilize or further reduce deforestation in the future. Such a program could create large-scale incentives to reduce tropical deforestation, as well as for broader developing country participation in the Kyoto Protocol, and leverage support for the continuity of the Protocol beyond the 2008–2012 first commitment period.     

Field observations of SPM using ADV, ADP, and OBS in a shallow estuarine system with low SPM concentration—Vitória Bay, SE Brazil

The present study investigated direct and indirect methods using optical and acoustic instruments for the acquisition of information required to estimate the concentration of suspended particulate matter (SPM) in Vitória Bay, a shallow estuarine system in SE Brazil. The aim was to calibrate and compare the use of different instruments (OBS, ADP, and ADV) to estimate SPM concentration in the water column and near the bed. Concentration was determined by correlating filtered water samples with the optical and acoustic measurements. In general, the methodology proved tenable for the chosen shallow estuarine environment with low SPM concentration (<60?mg/L). Pearson’s coefficient ranged from 0.75 to 0.85, when correlating measurements taken at three sampled depths. Differences in the correlation coefficient values showed that calibration at three depths (near the bed, mid-water column, and near the surface) was more effective than for surface samples alone, even in shallow (???m deep) water. When calibration was attempted for concentration in the entire water column with samples at just one elevation, the correlation value was very low, thus increasing the error in estimating the SPM concentration.     

Two-Way Regionalized Classification of Multivariate Datasets and its Application to the Assessment of Hydrodynamic Dispersion

Zones of mixing between shallow groundwaters of different composition were unravelled by “two-way regionalized classification,” a technique based on correspondence analysis (CA), cluster analysis (ClA) and discriminant analysis (DA), aided by gridding, map-overlay and contouring tools. The shallow groundwaters are from a granitoid plutonite in the Fundão region (central Portugal). Correspondence analysis detected three natural clusters in the working dataset: 1, weathering; 2, domestic effluents; 3, fertilizers. Cluster analysis set an alternative distribution of the samples by the three clusters. Group memberships obtained by correspondence analysis and by cluster analysis were optimized by discriminant analysis, gridded over the entire Fundão region, and converted into “two-way regionalized classification” memberships as follows: codes 1, 2 or 3 were used when classification by correspondence analysis and cluster analysis produced the same results; code 0 when the grid node was first assigned to cluster 1 and then to cluster 2 or vice versa (mixing between weathering and effluents); code 4 in the other cases (mixing between agriculture and the other influences). Code-3 areas were systematically surrounded by code-4 areas, an observation attributed to hydrodynamic dispersion. Accordingly, the extent of code-4 areas in two orthogonal directions was assumed proportional to the longitudinal and transverse dispersivities of local soils. The results (0.7–16.8 and 0.4–4.3 m, respectively) are acceptable at the macroscopic scale. The ratios between longitudinal and transverse dispersivities (1.2–11.1) are also in agreement with results obtained by other studies.     

Uncertainty quantification in numerical simulation of particle-laden flows

Numerical models can help to push forward the knowledge about complex dynamic physical systems. Modern approaches employ detailed mathematical models, taking into consideration inherent uncertainties on input parameters (phenomenological parameters or boundary and initial conditions, among others). Particle-laden flows are complex physical systems found in nature, generated due to the (possible small) spatial variation on the fluid density promoted by the carried particles. They are one of the main mechanisms responsible for the deposition of sediments on the seabed. A detailed understanding of particle-laden flows, often referred to as turbidity currents, helps geologists to understand the mechanisms that give rise to reservoirs, strategic in oil exploration. Uncertainty quantification (UQ) provides a rational framework to assist in this task, by combining sophisticated computational models with a probabilistic perspective in order to deepen the knowledge about the physics of the problem and to access the reliability of the results obtained with numerical simulations. This work presents a stochastic analysis of sediment deposition resulting from a turbidity current considering uncertainties on the initial sediment concentrations and particles settling velocities. The statistical moments of the deposition mapping, like other important features of the currents, are approximated by a Sparse Grid Stochastic Collocation method that employ a parallel flow solver for the solution of the deterministic problems associated to the grid points. The whole procedure is supported and steered by a scientific workflow management engine designed for high performance computer applications.     

New encoder–decoder convolutional LSTM neural network architectures for next-day global ionosphere maps forecast

GPS Solutions - In addition to traditional tide gauges, the ground-based global navigation satellite system reflectometry (GNSS-R) that utilizes signal-to-noise ratio data from a single GNSS...