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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
51

Analysis of Exoelectrogenic Bacterial Communities Present in Different Brine Pools of the Red Sea

Ortiz Medina, Juan F. 05 1900 (has links)
One contemporary issue experienced worldwide is the climate change due to the combustion of fossil fuels. Microbial Electrochemical Systems pose as an alternative for energy generation. In this technology, microorganisms are primarily responsible for electricity production. To improve the performance it is reasonable to think that bacteria from diverse environments, such as the brine pools of the Red Sea, can be utilized in these systems. Samples from three brine pools: Atlantis II, Valdivia, and Kebrit Deeps, were analyzed using Microbial Electrochemical Cells, with a poised potential at +0.2 V (vs. Ag/AgCl) and acetate as electron donor, to evaluate the exoelectrogenic activity by the present microorganisms. Only samples from Valdivia Deep were able to produce a noticeable current of 6 A/m2. This result, along with acetate consumption and changes on the redox activity measured with cyclic voltammetry, provides arguments to con rm the presence of exoelectrogenic bacteria in this environment. Further characterization using microscopy and molecular biology techniques is required, to obtain the most amount of information about these microorganisms and their potential use in bioelectrochemical technologies.
52

Extended life of swimming pools through LCC

Kroll, Stephan January 2012 (has links)
Swimming pools constructed with reinforced concrete require a high level of expertise within both, its planning and execution. To build waterproof concrete shells, extensive concrete technology knowledge, detailed planning of joint formation and high quality safety measures are needed. This thesis evaluates concrete technology features for swimming pool construction in Germany and Sweden. In particular, guidelines by DafStb, DIN and DgfdB provide the planner with detailed advice and specifics about swimming pools. It also gives an overview about the actual condition of swimming pools in Sweden that reached an age of at least 30 years and shows structural consequences of mistakes in planning and construction of swimming pools. The aspect of financial consequences is also analyzed. With the support of the software “Legep”, the methodology of LCC was used to estimate costs in the future. Additionally, a proposal of post tensioned concrete as a more sustainable technology for watertight concrete basins is shown and under equal aspects analyzed and compared.
53

Investigating the role of groundwater - surface water connectivity in supporting non-perennial river systems, Sandveld, Western Cape, South Africa

Pietersen, Raven Jesse January 2021 (has links)
>Magister Scientiae - MSc / Non-perennial rivers are characterised by a discontinuous and variable hydrological flow regime which may retreat to form isolated pools along the watercourse during prolonged dry periods. The resulting spatio-temporal variability in hydrological characteristics provides support for a variety of ecological habitats which promote species richness and biodiversity. It is well established that groundwater may offer flow supplementation to perennial river flow throughout the year as baseflow, while fewer authors have unpacked the nuances of the importance of groundwater in dynamics of water persistence and the conditions that determine non-perennial pool reoccurrence. This study explores river-aquifer interaction of the Verlorenvlei catchment within the Western Cape Province of South Africa as a case study in order to create an improved hydrogeological understanding of groundwater’s role in non-perennial rivers to improve of water management practices. A multi-method approach was designed to fulfil this aim. In addition to desktop literature review and in-field sampling of water for environmental tracers, a water presence, groundwater level, and geophysical survey was conducted in order to develop a conceptual understanding of the multi-scale interaction occurring within the Verlorenvlei basin. Results of the isotopic and chemical analysis of water sources revealed the water origin and groundwater flow dynamics for the Verlorenvlei. The contribution of groundwater from Table Mountain Group related, fault-driven flow to the groundwater balance of the Verlorenvlei creates regional gaining conditions. Local gaining conditions within the Verlorenvlei river are created through lateral input of upwelling groundwater which moves downgradient with the topography as evidenced by the hydrogeological and geophysical survey. Using the Verlorenvlei as a case study, a contribution is made to the knowledge of the role of groundwater in non-perennial rivers. The results presented in this study indicate that where basin hydrogeology allows, groundwater may play an important role in the supply of water to non-perennial pools, especially during periods of minimal rainfall. The interaction mechanisms of this groundwater contribution within non-perennial rivers are site specific and spatially variable. Basin hydrogeology, subsurface stratigraphy and water availability are key limiting factors to interaction in non-perennial rivers. Future research aimed at generating robust information on discrete zones of water presence along non-perennial rivers may allow for better assessment of the potential vulnerability of these areas to water loss. Where these areas are fed by groundwater, to accommodate for their vulnerability, groundwater capture maps may allow for investigation of the local impact of groundwater use on these areas.
54

The Prevalence and Prevention of Crosstalk: A Multi-Institutional Study

Edlund, John E., Nichols, Austin Lee, Okdie, Bradley M., Guadagno, Rosanna E., Eno, Cassie A., Heider, Jeremy D., Hansen, Edward J., Sagarin, Brad J., Blackhart, Ginette, Cottrell, Catherine A., Wilcox, Kenneth Tyler 04 May 2014 (has links)
It is a common problem in psychology subject pools for past study participants to inform future participants of key experimental details (also known as crosstalk). Previous research (Edlund, Sagarin, Skowronski, Johnson, & Kutter, 2009) demonstrated that a combined classroom and laboratory treatment could significantly reduce crosstalk. The present investigation tested a laboratory-only treatment for the prevention of crosstalk at five universities, along with institutional-level moderators of crosstalk. Results indicated the presence of crosstalk at all universities and that the laboratory-based treatment was effective in reducing crosstalk. Importantly, crosstalk rates were higher (but successfully neutralized) in research pools with higher research credit requirements. Therefore, this research provides valuable guidance regarding crosstalk prevalence and its minimization by researchers.
55

RESOURCE SUBSIDIES ACROSS THE AQUATIC-TERRESTRIAL BOUNDARIES OF TEMPORARY PONDS

Fritz, Kelley Ann 01 December 2017 (has links) (PDF)
Aquatic habitats are closely linked to surrounding terrestrial environments via reciprocal subsidies. Much of the research on these subsidies has been focused on streams, while subsidies across aquatic-terrestrial boundaries of other aquatic systems, like temporary ponds, have received little attention. Temporary ponds are seasonally inundated aquatic habitats and patterns of energy transport across transient aquatic-terrestrial boundaries are not well understood. To address the lack of information regarding these cross-habitat subsidies, I quantified: 1) leaf litter inputs, 2) amphibian egg inputs, 3) terrestrial insect inputs, 4) amphibian metamorph emergence, and 5) aquatic insect emergence for eight temporary ponds. Terrestrial insect inputs to ponds represented substantial high-quality subsidies to ponds that are generally unaccounted for in similar studies. While larger ponds produced greater total fluxes to terrestrial habitats, smaller ponds were often more productive per unit area. Therefore, a mosaic of small ponds may produce greater or equivalent subsidies and may be of greater value to terrestrial food webs than a single large pond. Resource subsidies of energy and nutrients can be transported via physical forces or biotic processes, such as animal migration or emigration. I quantified net nutrient fluxes associated with amphibian migrations across aquatic-terrestrial boundaries of eight temporary ponds in Illinois. I measured carbon (C), nitrogen (N), and phosphorus (P) subsidies from forests to ponds, in the form of eggs, and the reciprocal subsidies from ponds to forests via juvenile emigration. Juvenile emergence biomass did not resemble egg biomass, as not all species bred successfully in each pond, resulting in variability in the magnitude of nutrient fluxes both across ponds and species. The forest was not always the recipient system of net nutrient fluxes. Hydroperiod, trophic interactions, and species composition explained some dynamics of N and P subsidies. Most studies have focused on the magnitude of cross-boundary fluxes, but the impact of a subsidy is mediated by the size of the flux as well as the quality and relative abundance of similar resources in the recipient habitat. Long-chain polyunsaturated fatty acids (LC-PUFAs) are necessary for proper physiological function, are unevenly distributed across the landscape, and animals differ greatly in their ability to synthesize them de novo. This creates the potential for limitation and increases their possible importance as a subsidy. I examined LC-PUFA tissue concentration and export in eight species of emerging amphibian metamorphs across eight temporary ponds in a wetland complex. I found that tissue concentrations and export of LC-PUFAs varied across species, but were generally within the ranges of several freshwater fish and aquatic insects. Anurans exported higher amounts of LC-PUFAs than salamanders, largely due to the higher emergence biomass of anurans. Further, I explored fatty acid profiles and immune function of wolf spiders in wetland and upland habitats. Wetland spiders had higher tissue levels of aquatic-derived LC-PUFAs and elevated immune function compared to upland spiders. These patterns suggest aquatically derived nutrients, such as LC-PUFAs, may benefit organisms exploiting freshwater habitats.
56

Phagotrophic Phytoflagellates across Ecosystems: Their Functional Role in the Southern Ocean and Mid-Atlantic Vernal Pools

Van Kuren, Andrew, 0009-0000-7393-4689 January 2023 (has links)
Much of the world’s aquatic food webs and nutritional relationships have been blurred by the ever-increasing evidence that many phytoplankton are not exclusively heterotrophic or autotrophic, but instead mixotrophic. Mixotrophy is a continuum of different energy and carbon-acquisition mechanisms utilizing both autotrophy and heterotrophy which distorts the concept of single trophic tier modality. This makes mixotrophs flexible to adapt to environmental pressures and is becoming more the rule than the exception in many aquatic ecosystems. One unique environmental setting where mixotrophy could be highly beneficial to food web stability is in seasonally occurring ephemeral pools – aka vernal pools. Mid-Atlantic vernal pools are biodiverse biogeochemical hotspots and critical breeding habitats for a diverse number of endemic taxa including many endangered amphibian species. Vernal pools are not permanent standing bodies of water and have fluxes in hydrology, temperatures, nutrients, and irradiance to name a few. These extremes make vernal pools an ideal setting for mixotrophic phytoplankton, however it’s never been investigated. Our survey found mixotrophy in every vernal pool sampled, as well as elevated grazing rates in pools experiencing nontypical seasonal conditions. From these small-scale forest pools to the world’s oceans mixotrophy is a widespread nutritional strategy. The Southern Ocean is essential for powering worldwide ocean circulation, regional biogeochemical cycles, and global climate. One of the major hurdles with understanding mixotrophy is identifying the phytoplankton capable of shifting nutritional strategies. While many Southern Ocean plankters have been properly identified as mixotrophic, one such keystone species has gone mislabeled until now. Phaeocystis antarctica is a well-studied Haptophyte algae that plays major roles in the global carbon and sulfur cycles. This species has been historically labeled as an obligate phototroph, but contradictory survives the long dark Antarctic winter without any known evidence of encystment. We suspect that this highly abundant species is in fact mixotrophic, capable of phagocytosis to supplement the irradiance shortcomings of the Antarctic dark. We experimented with varying degrees of light and nutrient limitations to determine possible triggers for P. antarctica grazing. Our results showed P. antarctica ingesting in every treatment, but its highest grazing rates corresponded with limitations to its primary photosynthetic mode. Apart from the newly realized complexity P. antarctica brings to the Southern Ocean food web, it is an environment that suffers from microplastic pollution that can impede these mixotrophic species. Mismanaged plastic waste around the world, especially microfiber discharge from laundered synthetic textiles, escape into the natural environment, and eventually concentrate in the oceans. The Southern Ocean can become disproportionately polluted in regions due to microfibers becoming sequestered once crossing the Antarctic circumpolar current and even becoming trapped in sea-ice formations. While it is easy to see the devastation plastic waste has on megafauna (i.e. turtles, fish, birds, and whales), its microscopic devastation is less obvious. Plastic waste comes in many forms and one less researched form is buoyant polyester microfibers <1mm that interact with colony forming algae. We utilized different concentrations of polyester microfibers and mixing speeds to determine if microfiber interactions with colony formations increases or decreases overall colony buoyancy. Smaller concentrations of polyester microfibers can impart a positively buoyant effect onto P. antarctica colonies regardless of mixing speed, however larger concentrations negatively affected colony buoyancy regardless of mixing speed. / Biology
57

Městské lázně / The Municipal Baths

Stružková, Jaroslava January 2010 (has links)
The theme of the project is an architectural design of a municipal baths situated in a space between a Voroněž hotel and Svratka river in city Brno. The project contains design of urban space in reference to the ground surrounding and the architectural, disposal, structural and material design of the building for municipal baths at the demanded place.
58

Spontaneous expansion and mobilization of a discontinuous gas phase due to mass transfer from dense non-aqueous phase liquid / SPONTANEOUS EXPANSION AND MOBILIZATION OF GAS ABOVE DNAPL

Mumford, Kevin G. 10 1900 (has links)
Included in this file is a CD drive titled "Chapter Three: Supporting Information" with a 00:40 second long animation. For best quality, view in VLC, not Quicktime Player. / <p>Groundwater contamination by dense non-aqueous phase liquids (DNAPLs ), such as chlorinated solvents, continues to be a significant environmental problem. When released to the subsurface, either due to improper disposal or accidental release, DNAPLs can form complex source zones whose geometry is largely controlled by the geological heterogeneity of the subsurface. These source zones are composed of disconnected, immobile blobs or ganglia trapped by capillary forces (referred to as DNAPL residual) between high-saturation regions located at permeability interfaces (referred to as DNAPL pools). The slow dissolution of DNAPL pools can result in the contamination of groundwater for time periods on the order of decades to centuries.</p> <p>The common conceptual model used in the investigation of DNAPL-contaminated sites is based primarily on the mass transfer from DNAPL to the surrounding aqueous phase in the saturated zone. However, the presence of a discontinuous gas phase above a DNAPL pool can significantly affect the mass transfer from the pool through repeated, spontaneous expansion and mobilization of the gas phase. This mechanism has not been included in the common conceptual models.</p> <p>The goal of this research was to develop a quantitative understanding of discontinuous gas phase expansion and mobilization above a DNAPL pool. This goal was addressed using a combination of small-scale and intermediate-scale laboratory experiments. Small-scale, no-flow vial experiments were used to measure the expansion of single gas bubbles above DNAPL pools, and provide the basis for the development of an analytical model to assess the effect of expansion by multi-component partitioning on the mass transfer from DNAPL pools. Small-scale flow cell experiments were used to measure spontaneous expansion rates in porous media, and provide visual data concerning the distribution of the gas phase. Small-scale air injection experiments were used to characterize the gas flow. Finally, an intermediate-scale flow cell experiment was used to provide larger-scale data concerning the transient distribution of the gas phase, and measure the effect of spontaneous expansion and mobilization on the aqueous-phase DNAPL constituent concentrations.</p> <p>The combined results of these experiments established a detailed conceptual model for the spontaneous expansion and mobilization of a discontinuous gas phase above a DNAPL pool. In this conceptual model, spontaneous expansion of a discontinuous gas phase above a DNAPL pool occurs due to multi-component partitioning, and depends on the concentrations of both the volatile DNAPL and the other dissolved gases. This expansion is more likely to occur, and will be faster, in shallower systems (i.e. lower hydrostatic pressures) containing coarser media (i.e. lower capillary pressures), more volatile DNAPL, and higher concentrations of other dissolved gases (i.e. higher partial pressures). Mobilization of the expanding gas will occur as discontinuous gas flow in most sands, where the repeated trapping and coalescence of gas clusters can allow rapid, large-scale vertical transport of the gas phase. This discontinuous gas flow can produce macroscopic gas fingers composed of multiple, discrete gas clusters. These macroscopic fingers can reach substantial heights above the pool surface, but the growth occurs predominantly at the pool's leading edge due to the stripping of other dissolved gases. This expansion and mobilization can significantly affect the mass transfer from the DNAPL pool if the gas phase is in direct contact with the pool surface; or if the gas phase is close to the pool surface, covers a large fraction of the pool, and the groundwater flow is sufficiently slow. The partitioning of DNAPL constituent from the mobilized gas phase to the aqueous phase well above the pool surface can also change the spatial distribution of aqueous-phase DNAPL constituent concentrations, increasing them above those that are expected based on theoretical calculations for strictly DNAPL-water systems, even at elevations where the concentrations are expected to be zero. The increased concentrations well above the pool surface can appear as short-duration events in the presence of a sustained gas phase, due to the partitioning of DNAPL constituents from the gas to the aqueous phase during multi-component mass transfer. The results of this research provide the necessary basis to begin incorporating this fundamental mechanism into the conceptual and mathematical models used for DNAPL-related research, the investigation ofDNAPL-contaminated sites, and the design and application of DNAPL remediation technologies.</p> / Thesis / Doctor of Philosophy (PhD)
59

Evaluation of the Conflict Prevention Pools: Russia and the Former Soviet Union

Austin, Greg, Bergne, P. January 2004 (has links)
yes / P5. The evaluation was undertaken by Bradford University, Channel Research Ltd, the PARC & Associated Consultants. The GCPP Russia and Former Soviet Union (FSU) Case study was carried out by Dr Greg Austin with Mr Paul Bergne. Work was conducted in three phases. The first was London-based, and considered the Russia and FSU Strategy¿s activities in the context of UK approaches to conflict prevention in the region and the overall policy framework of the GCPP. The second phase involved fieldwork in Georgia, Russia, Azerbaijan, Armenia, Kyrgyzstan and Kazakhstan, whilst the third phase involved consultations in London. P7. The Russia and FSU Case Study is one of six studies undertaken within the framework of the evaluation of the Conflict Prevention Pools. In accordance with the Terms of Reference (ToRs) and the Inception Report, the Evaluation placed maximum emphasis on the macro level: the policy processes in Whitehall by which decisions on allocations are made and implemented by the CPPs. Considerable attention has also been placed on the meso level: the degree to which CPP policies and activities in a given conflict form part of a coherent package of direct interventions by the international community and local actors to the problems of particular large scale deadly conflicts or potential conflicts. The microlevel of analysis (review of specific projects) confines itself largely to the way in which projects impact on the meso and macro levels. The Evaluation has not analysed systematically whether specific projects funded by the CPPs have been well managed and whether they have achieved their specific project goals. Single projects have been analysed to the extent that they reflect on the macro and meso levels. P8. The main findings of the evaluation, reflected in this Synthesis Report, are that the CPPs are doing significant work funding worthwhile activities that make positive contributions to effective conflict prevention, although it is far too early in the day to assess impact. The progress achieved through the CPP mechanisms is significant enough to justify their continuation.
60

Sanitary Aspects of the Swimming Pool of North Texas State Teachers College, Denton, Texas

Self, Louise 08 1900 (has links)
This investigation was conducted in order to show that insanitary conditions may exist in the swimming pool at North Texas State Teachers College provided the proper precautions are not taken; and, in contrast that this pool can be sanitary and entirely safe when operated and used according to the necessary sanitary specifications.

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