Este trabalho apresenta os parâmetros de transporte e atenuação dos íons \'K POT.+\', \'CU POT.2+\' e \'CL POT.-\' obtidos em ensaios de coluna, para uma mistura compactada e saturada de solos lateríticos da Formação Botucatu e Serra Geral. As soluções contaminantes percoladas foram cloretos de potássio e de cobre em três diferentes concentrações. Os resultados obtidos estão apresentados na forma de curva de chegada e os parâmetros de transporte e atenuação foram estimados através do ajuste de curvas teóricas aos dados experimentais das colunas. A mistura compactada mostrou-se satisfatória para o uso em barreiras selantes (liner) uma vez que os resultados de condutividade hidráulica e de sorção dos íons estudados são razoáveis. / This paper presents transport and attenuation parameters of \'K POT.+\', \'CU POT.2+\' e \'CL POT.-\', obtained in columns test using a compacted and saturated mixture of two lateritic soils from Botucatu and Serra Geral formation. The contaminant leaching solution was composed of KCl and \'CU\'CL IND.2\'.2\'H IND.2\'O\' with concentrations three different. The results obtained are presented in the form of breakthrough curves and the transport and attenuation parameters estimated through fitting procedures of the theorical curves related to the real column data. The compacted mixture showed to be satisfactory for liner usage since the results of the hydraulic conductivity and the ions sorption in these soils are reasonable.

Among natural disasters affecting the United States, North Atlantic tropical cyclones (TCs) and hurricanes are responsible for the highest economic losses and are one of the main causes of fatalities. Although we cannot prevent these storms from occurring, skillful seasonal predictions of the North Atlantic TC activity and associated impacts can provide basic information critical to our improved preparedness. Unfortunately, it is not yet possible to predict heavy rainfall and flooding associated with these storms several months in advance, and the lead time is limited to few days at the most. On the other hand, overall North Atlantic TC activity can be potentially predicted with a six- to nine-month lead time. This thesis focuses on the evaluation of the skill in predicting basin-wide North Atlantic TC activity with a long lead time and rainfall with a short lead time. For the seasonal forecast of TC activity, we develop statistical-dynamical forecasting systems for different quantities related to the frequency and intensity of North Atlantic TCs using only tropical Atlantic and tropical mean sea surface temperatures (SSTs) as covariates. Our results show that skillful predictions of North Atlantic TC activity are possible starting from November for a TC season that peaks in the August-October months. The short term forecasting of rainfall associated with TC activity is based on five numerical weather prediction (NWP) models. Our analyses focused on 15 North Atlantic TCs that made landfall along the U.S. coast over the period of 2007-2012. The skill of the NWP models is quantified by visual examination of the distribution of the errors for the different lead-times, and numerical examination of the first three moments of the error distribution. Based on our results, we conclude that the NWP models can provide skillful forecasts of TC rainfall with lead times up to 48 hours, without a consistently best or worst NWP model.

Bridge scour is the leading cause of bridge damage nationwide. Successfully mitigating bridge scour problems depends on our ability to reliably estimate scour potential, design safe and economical foundation elements that account for scour potential, identify vulnerabilities related to extreme events, and recognize changes to the environmental setting that increase risk at existing bridges. This study leverages available information, gathered from several statewide resources, and adds watershed metrics to create a comprehensive, georeferenced dataset to identify parameters that correlate to bridges damaged in an extreme flood event. Understanding the underlying relationships between existing bridge condition, fluvial stresses, and geomorphological changes is key to identifying vulnerabilities in both existing and future bridge infrastructure. In creating this comprehensive database of bridge inspection records and associated damage characterization, features were identified that correlate to and discriminate between levels of bridge damage. Stream geomorphic assessment features were spatially joined to every bridge, marking the first time that geomorphic assessments have been broadly used for estimating bridge vulnerability. Stream power assessments and watershed delineations for every bridge and stream reach were generated to supplement the comprehensive database. Individual features were tested for their significance to discriminate bridge damage, and then used to create empirical fragility curves and probabilistic predictions maps to aid in future bridge vulnerability detection. Damage to over 300 Vermont bridges from a single extreme flood event, the August 28, 2011 Tropical Storm Irene, was used as the basis for this study. Damage to historic bridges was also summarized and tabulated. In some areas of Vermont, the storm rainfall recurrence interval exceeded 500 years, causing widespread flooding and damaging over 300 bridges. With a dataset of over 330 features for more than 2,000 observations to bridges that were damaged as well as not damaged in the storm, an advanced evolutionary algorithm performed multivariate feature selection to overcome the shortfalls of traditional logistic regression analysis. The analysis identified distinct combinations of variables that correlate to the observed bridge damage under extreme food events.

acase@tulane.edu

acase@tulane.edu

acase@tulane.edu

acase@tulane.edu

This study was designed to investigate the impact of some environmental factors on the survival and behavior of the larval stages of Heterobilharzia americana, a mammalian schistosome that is restricted in distribution to the Gulf of Mexico states and the Carolinas. The chemostimulation of the miracidia by calcium and magnesium ions in different ratios of the two was also attempted. The effect of light and gravity on the miracidia and cercariae were investigated using tubes in horizontal and vertical positions with different illumination levels. The miracidia were found to be negatively geotropic and positively phototropic. Such behavior facilitates their contact with the snails. The cercariae were also found to behave in the same way, so to bring them to the proximity of the mammalian host. To study the effect of temperature and chemical factors on miracidia, wells of culture plates were used to expose the miracidia to such factors; their survival at different intervals was recorded. The survival of the miracidia increased with a decrease in temperature while snail infection took place at low as well as at high temperatures, with the optimum being at room temperature (24-25(DEGREES)C). The miracidia survived at salinity ranges between 0.02 and 0.1% NaCl with optimum survival occurring between 0.02 and 0.04% NaCl. The optimum pH for survival of the miracidia was found to be between 7 and 8, and they survived better when the pH was alkaline than when it was acidic. The miracidia were found to tolerate calcium better than magnesium, but survival was found to be better when both ions were present. The results indicate that these factors may have a direct impact on larval survival which might affect the distribution of the parasite if extreme ranges of the factors happen to occur in nature. In order to study the effect of calcium and magnesium on miracidial chemostimulation, a modified dialysis membrane chamber (DMC) was used. Chemostimulation of miracidia was demonstrated using well water conditioned by the snail Lymnaea (Pseudosuccinea) columella. Solutions of different Ca('++)/Mg('++) ratios were tested in DMC and their effects were observed. It was found that alteration in the miracidial behavior decreased as the calcium ion concentration increased and the magnesium ion concentration decreases in the solution tested. . . . (Author's abstract exceeds stipulated maximum length. Discontinued here with permission of author.) UMI / acase@tulane.edu

acase@tulane.edu

acase@tulane.edu