This research was conducted to better understand the corrosion propagation stage on dry-cast reinforced concrete pipes (DCRCPs) while exposed to high moisture conditions and chlorides. Corrosion initiation and propagation were studied in instrumented specimens obtained from segments of dry-cast reinforced concrete pipes. All specimens were subjected to accelerated chloride transport by the application of an electric field. Corrosion of the steel wire mesh initiated after a few days to a few months rather than several years. The specimens were then transferred to high moisture environments (immersed in water, high humidity and/or covered with wet sand) during the corrosion propagation stage. Reinforcement potentials, linear polarization resistance (LPR) and Electrochemical Impedance Spectroscopy (EIS) measurements were carried out periodically. During the propagation stage in different exposures, reinforcement eventually reached negative potentials values (< –-0.55 Vsce), which suggest mass transfer limitations. These specimens showed no visual signs of corrosion such as cracks or corrosion products except the ones exposed to high humidity and laboratory environments; where some corrosion products have reached the concrete surface. Moreover, the apparent corrosion rate values obtained suggest high corrosion rates. No crack appearance on specimens exposed to other conditions could be explained by the porosity of the specimens; the corrosion products moved into saturated pores. It is speculated that although there might be mass transfer limitations present, the current demanded by the anode is being balanced by a larger cathode area due to macrocell effects since the high moisture conditions likely reduced the concrete resistivity and increased the throwing power. The corrected polarization resistance (Rc) was calculated by subtracting the solution resistance from the apparent polarization resistance measured. The Rc values measured over time were used to obtain the calculated mass loss (using Faraday’s Law). Most specimens were forensically analyzed and the measured mass loss compared to the calculated mass loss. The forensic examination includes the measurement of the actual corroding areas. The measured corroding areas were used to obtain corrosion current density (icorr) values. A comparison was made of the calculated corrosion current densities obtained using the linear polarization resistance method (LPR) and the extrapolation method from cyclic polarization tests. It was evident that most of the specimens’ corrosion rates were significantly high. The corrosion products filled the wet-pores inside the concrete and provide an explanation for no cracks or corrosion bleed outs being visually observed on the specimens. / Includes bibliography. / Dissertation (Ph.D.)--Florida Atlantic University, 2019. / FAU Electronic Theses and Dissertations Collection

Abstract There has been a steady increment in economic growth in Uganda and as the economy is on the rise, the demand for energy also increases. Hydro power energy production has been growing in Uganda as a result of the different types of dams created in Uganda along the River Nile. Uganda has been trying to reach the target of electricity capacity so as to ensure that her people get the energy required to improve on their livelihoods. Uganda as a whole has different energy sources but in this thesis, Bujagali dam will be at the center of the focus. Looking at the social and environmental impacts made upon its construction in Jinja. The main objective of this thesis was therefore to show how the livelihoods of the people dwelling in the neighborhood and the environment were affected by the construction of the dam. The livelihoods of the people before the construction of the dam were reviewed in regard to their social life as well as the environment from past literature provided. The different aspects in which the people and environment were affected after the construction of the dam were also reviewed through different interviews with the residents of Bujagali.   There were both positive and negative effects, socially, environmentally and economically due to the construction of the Bujagali. The positive social effects were: provision of land for farming, provision of employment opportunities for the residents, increase in tourism at the dam, the falls and the cultural centers, community development including education, health facilities, skill training, water supply and power supply while the negative effects were loss of land, cultural loss, and less access to different points of the river for fishing purposes for the residents. The positive environmental effects were increase in fish species, more health and safety awareness, and thermal plants closure hence less green house gases effects on the ozone layer, the noise levels effects due to the dam construction, were of no consequence as they were in the required standard.  The negative environmental effects were majorly water levels fluctuation that affects the head of water which in turn affects the capacity of power produced at the dam and air quality of the area during and after the construction of the dam especially air emissions. The positive economic effects were: increment of power to the national grid, lower electricity costs, closure of thermal plants as they were expensive to run and maintain and reduction of load shedding. The negative effect was the financial loan that the government of Uganda obtained to construct the dam that has to be paid back.

No description available.

Fish can bioconcentrate complex mixtures of xenobiotics arising from exposure to wastewater effluents discharged into surface waters. Wastewaters contain a complex mixture of organic compounds and little is known about their uptake into fish and their health effects. In this study, a chemical profiling approach was used to characterize the profile of xenobiotics and their metabolites (the xenometabolome) in biofluids (bile and plasma) of juvenile rainbow trout (Oncorhynchus mykiss) exposed to a wastewater effluent. Metabolite profiles of effluent-exposed fish were compared with that from control fish exposed to uncontaminated river water. Samples were analysed by ultra performance liquid chromatography-time-of-flight mass spectrometry and data analysed by multivariate statistics. Exposure to effluent resulted in accumulation in trout bile of alkylsulfophenyl and alkylpolyethoxy carboxylates, as well as glucuronide conjugates of nonylphenol ethoxylates, alcohol ethoxylates, naphthols, chlorinated xylenols and phenoxyphenols, chlorophenes, resin acids, mefenamic acid and oxybenzone. Nonconjugated or sulphate conjugates of many of these contaminants were also detected in plasma of effluent-exposed trout. In addition, changes in the concentrations of endogenously derived metabolites were also detected in trout plasma, and these included an increase in blood bile acids, methylbutryolcarnitine and a decrease in sphingosine levels. These observations were verified in a further exposure of sexually mature roach (Rutilus rutilus) to concentrations of the same effluent. Exposure to 50% or 100% effluent resulted in dose dependent increases in blood concentrations of xenobiotics, taurocholic acid, syprinol sulphate and lysophospholipids and decreases in sphingosine levels. This work reveals the complex nature of xenobiotics accumulating in effluent-exposed fish together with the identification of changes in concentrations of lipid metabolites associated with hepatotoxicity. These results reveal, for the first time, that metabolite profiling techniques can be used to screen for uptake of complex mixtures of contaminants into fish and also for the detection of natural metabolite pathways in the organism that are disrupted due to exposure to multiple xenobiotics.

The cumulative effects of watershed development and large water withdrawals are placing the sustainability of freshwater resources at risk due to alteration of watershed hydrology, stream geomorphology, groundwater recharge, and adverse effects to the aquatic ecology of water resources. The consideration of cumulative environmental effects in development decisions under current project-specific assessment does not fully encompass the interacting effects of multiple stressors over space and time. As a result, the cumulative effects of land uses and development on watershed processes are not properly assessed and managed. There is a recognized need to shift from local, project-scale cumulative effects assessments to broader, landscape, or regional scale assessments to accurately assess cumulative effects to watershed processes and river system condition. The problem is that there is little understanding of the current capacity to do so. This research: i) developed a set of indicators for evaluation of regional capacity to support watershed cumulative effects assessment and management (CEAM) requisites, ii) applied those indicators to the South Saskatchewan Watershed (SSW), iii) identified capacity needs and constraints to watershed CEAM in SSW, and iv) identified lessons learned and opportunities for capacity building to support watershed CEAM principles and practice. Capacity indicator questions were developed for a set of eight institutional requirements for watershed CEAM, identified from a previous study of watershed CEAM in the SSW. Research methods included a web-based survey of academics, regulators, industry and environmental organizations, which consisted of both closed ended and open-ended questions based on the capacity indicators. Survey results were analyzed using the Statistical Package for the Social Sciences and qualitative methods. Results indicate that the primary threats to water quality and quantity in the SSW, as identified by study participants, are broad-scale stressors that are not subject to project-specific environmental assessment regulations. To address these broad-scale stresses, cumulative effects assessment at the regional level needs to be done; however, it was identified that there is currently a lack of mechanisms to support watershed CEAM. The need for a lead agency, multi-stakeholder collaboration, and financial and human resources were identified as the most important requisites from the research results for implementing and sustaining watershed CEAM programs. Research results revealed that watershed CEAM cannot be driven solely ‘bottom-up’ and government must lead watershed CEAM activities. Participants noted that there is collaboration ongoing in the SSW to meet CEAM objectives, but it is limited. There is a lack of clarity around common goals for watershed and sub-watershed management, and a lack of transparency in sharing data. Many participants commented that expertise is available for watershed CEAM, but there is a lack of organizational and financial resources to develop successful plans and actions.

The aim of this study was to assess the environmental effects of Moshyttan, one of the earliest known blast furnaces in Europe (ca. 11th century). The study was based on the analysis of three lake records in the immediate surroundings of the smelter. Fickeln lies directly downstream and is the main recipient of waterborne pollution. Mosjökälla lies directly upstream and served as the main water reservoir for the water-powered bellows. Kramptjärnen lies 1 km to the NW in a separate catchment and acts as a reference. The data includes 31 elements analyzed by X-ray fluorescence spectroscopy (XRF), organic content inferred from loss on ignition (LOI), biogenic silica (BSi) modeled from Fourier-transform infrared spectroscopy (FT-IRS) for all lakes and diatom counts for Fickeln. Two other studies provided dating of slag from the smelter and pollen- and geochemical data from Fickeln. The results show that the metallurgy and associated activities (e.g. agriculture, forest grazing and charcoal production) led to eutrophication and alkalization in Fickeln. This is indicated by the diatom community that in the background is dominated by benthic genera indicative of oligotrophy and dystrophy (Frustilia, Brachisyra and Eunotia) that during the active smelter phase is replaced by pelagic genera indicative of eutrophy (Aulacoseira and Asterionella). BSi also decreases after smelter establishment, which speculatively could indicate an overall decrease in diatom production. At the same time, a suite of elements commonly associated with iron processing (Fe, Pb and Zn) increase in the sediment.

Because differences often exist between species in their tolerances to environmental conditions, locations characterized by extreme parameter values (i.e., high temperature, low DO, high turbidity) may provide refuges from predation or competition by altering the outcome of inter-species interactions. This thesis examined the effects and relative importance of water temperature, dissolved oxygen (DO) and turbidity on habitat use by fish species and resulting changes in community composition. The effects of abiotic factors on predator-prey interactions were tested using field surveys, laboratory experiments, field experiments and computer modeling. Field surveys were conducted in Blind Channel, Delta Marsh, Manitoba, and on Lake Winnipeg, Manitoba, to determine if small bodied forage species preferentially used high temperature, low DO or high turbidity habitats and whether predator species avoided these locations. Prey species were more abundant in these extreme locations at both small (Blind Channel) and large (Lake Winnipeg) spatial scales, but predator avoidance was only documented in Blind Channel. The tolerances of fish species to moderate hypoxia (< 3 mg/L DO) was tested in the laboratory to verify that differences did exist among species and that the observed species distributions were not solely the effect of temperature. To quantify the potential for moderately hypoxic locations to provide a refuge from predation for small fish, a field manipulation was conducted in Blind Channel; hypoxic habitats were created without altering water temperature, decoupling the natural covariation between these two factors that occurs in aquatic systems. The abundance of small forage fish was higher in the hypoxic locations compared to controls and while predators still visited the hypoxic habitats, their mean visit duration was reduced from around 300 min to less than 1 min. An individual based computer model was used to test and illustrate current understanding of the relative importance of temperature, DO and turbidity on predator habitat selection decisions and fish community composition. The model showed that DO had a stronger effect on community composition than temperature, and that reduced foraging success from high turbidity was able to overpower the other two factors. Hypoxia affects habitat selection decisions by fish species and can provide refuges from predation and competition, helping maintain higher species diversity. Water temperature appears to have a weaker effect on fish distributions than DO while turbidity primarily affects visual predators, though the strength of turbidity effects depends on the magnitude and duration of individual events. / February 2008

The aim and purpose of this report is to describe how the domestic tobacco industry is affectingsustainable development in Malawi. This is done by describing the environmental and socio-economic effects ofthe cultivation and selling of tobacco leaves. Together with an outlook on the future developments of the industry,this information is used to describe how the Malawian tobacco industry corresponds to sustainable developmentand how it can be changed to improve sustainability in the country. The report is based on a literature study andtwo interviews. Theories on sustainable development and developmental concepts form the theoreticalbackground for the report. The conclusion of the report is that the situation regarding the Malawian tobaccoindustry is a complex one, where direct economic benefits are the main motive, but various socio-economic andenvironmental effects combine to make the situation unsustainable in a number of aspects. The suggestion of thisreport is to turn away from the current high dependence on tobacco to a more diversified agriculture, wheredifferent types of food crops substitute tobacco as the main source of income, while at the same time providingmore food in a country where poverty and malnutrition are problematic issues.

Diss. Linköping : Univ.

Computational modelling of chemical systems is most easily carried out in the vacuum for single molecules. Accounting for environmental effects accurately in quantum chemical calculations, however, is often necessary for computational predictions of chemical systems to have any relevance to experiment. This PhD thesis focuses on accounting for environmental effects in quantum chemical calculations by quantum mechanics/ molecular mechanics (QM/MM) approaches, taking on diverse examples from the solid state, the liquid phase and the protein environment. The methods are applied to compute a variety of properties from transition metal NMR properties of molecular crystals and enzymes, via conformational properties of zwitterions in aqueous solution, to an intramolecular amidation reaction in peptides. Chapter 3 concerns QM/MM calculations of molecular properties in the solid state, both molecular crystals and metalloenzymes, with a focus on transition metal chemical shift and EFG properties. We demonstrate that solid-state effects on such properties in molecular crystals can be accounted for by a simple general black-box QM/MM approach. We also describe preliminary QM/MM calculations of 51V anisotropic NMR properties for a vanadium-dependent enzyme. In Chapter 4 the focus is on solvent effects on the conformational preference of a small zwitterionic molecule, 3F-γ-aminobutyric acid (3F-GABA), calculated using QM/MM molecular dynamics simulations. NMR spin-spin coupling constants in solution are also calculated. Our simulations highlight the difficulty of accounting for solvation effects well enough to achieve agreement with experimental observations. Chapter 5 concerns the reaction mechanism of an intramolecular amidation reaction in a bacterial peptide, predicted by QM/MM calculations. We predict a reaction mechanism that accounts well for the experimental observations both for the wild-type and mutants. We demonstrate that environmental effects can often be satisfactorily accounted for by QM/MM approaches, thus helping to bridge the gap between theory and experiment.