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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.
31

Plasma Ion Concentrations in Selected Fishes from Four North Central Texas Reservoirs with Different Salinities

Del Regno, Kenneth J. (Kenneth Joseph) 12 1900 (has links)
Mean salinity concentrations in the four reservoirs (Moss, Ray Hubbard, Texoma and Possum Kingdom) ranged from 0.2 ppt in Moss Lake to 2.01 ppt in Possum Kingdom Lake. Reservoir sodium and chloride concentrations were hypotonic to hypertonic to plasma levels in all species. Interspecific differences were seen in ionic concentrations within each reservoir. Total osmotic and sodium concentrations in carp, Cyprinus carpio, were correlated to their concentrations in the reservoirs. No such relationship was noted for chloride, potassium and calcium. A laboratory study indicated that fish collection by electroshock did not bias plasma ion concentrations. Exposures to wide variations in ionic concentrations did not appear to induce stress in the species studied.
32

Origin, evolution, and mixing of saline and dilute groundwaters in three regional flow systems, midcontinent, U.S.A.

Musgrove, MaryLynn, 1964- 06 February 2013 (has links)
Lower Paleozoic strata in southeastern Kansas, southwestern Missouri and northern Oklahoma are predominantly marine carbonates that comprise portions of three regional flow systems. Groundwaters in these three adjacent systems exhibit extreme chemical and isotopic variations that delineate large-scale fluid mixing processes and two distinct mechanisms for the generation of saline fluids. Hydrodynamic and geochemical data closely correlate with geographic location and indicate that each system contains waters of markedly different origins. Results of elemental and isotopic mass balance modeling demonstrate that fluid mixing processes exert a fundamental control on groundwater compositions over the 40,000 km² study area. This quantification of groundwater mixing provides an important basis for determining endmember water compositions and evaluating hydrologic models for these flow systems. The three endmember groundwaters are as follows. 1) Dilute modern-day meteoric waters of the Ozark Plateaus aquifer system, recharged to southern Missouri. The evolution of this groundwater is dominated by interaction with host limestone and dolomite aquifer rocks. 2) Eastward migrating, saline Na-Ca-Cl groundwaters from the northern part of the Western Interior Plains aquifer system in central Kansas. These groundwaters are of meteoric origin with distant recharge areas. Salinity is acquired via the subsurface dissolution of Permian halite and subsequent water-rock interaction with silicate minerals. The chemical signature of these groundwaters, coupled with the presence of brines resulting from the dissolution of Permian halite in central Kansas, allow development of a model for the formation of saline Na-Ca-Cl fluids, a common component of many sedimentary basins. Additionally, the large-scale topographically driven flow of the northern part of this aquifer system is a modem analog for models of similar ancient systems. 3) Na-Ca-Cl brines in north-central Oklahoma. In contrast to the other saline endmember, the geochemical signature of endmember 3 groundwater, integrated with hydrogeologic data, indicate that this groundwater may represent a marine-derived brine from the deep Anadarko Basin. / text
33

Biological pretreatment of produced water for reuse applications

Kwon, Soondong, 1973- 29 August 2008 (has links)
Co-produced water from the oil and gas industry represents a significant waste stream in the United States. Produced water is characterized by high levels of total dissolved solids (TDS), dissolved organics and oil and grease. Among the wide variety of organics present in the water, the concentration of hazardous substances such as benzene, toluene, ethylbenzene, and xylenes (BTEX) can reach 600 mg/L and the concentration of non-hazardous carboxylate can be as high as 10,000 mg/L (API, 2002). Regulations governing the disposal of produced water are tightening and the interest in reusing treated produced water is increasing in the United States particularly in regions with scarce water supplies. In order to reuse produced water, removal of both the inorganic dissolved solids and hazardous organics such as BTEX may be necessary. The main goal of this research was to investigate the feasibility of using a combined physicochemical/biological treatment system to remove the organic constituents present in saline produced water. In order to meet this objective, two separate biological treatment techniques were investigated: a vapor phase biofilter (VPB) to treat the regeneration off-gas from an upstream surfactant-modified zeolite (SMZ) adsorption system and a membrane bioreactor (MBR) to treat the carboxylate and BTEX constituents that penetrate an upstream SMZ system. Each of the biological pretreatment systems was investigated first in the laboratory treating synthetic produced water and then in the field coupled to an SMZ adsorption system treating produced water. Both of the biological treatment systems were capable of removing the BTEX constituents both in the laboratory and in the field over a range of operating conditions. For the VPB, separation of the BTEX constituents from the saline aqueous phase yielded high removal efficiencies. However, carboxylates remained in the aqueous phase and were not removed in the combined VPB/SMZ system. In contrast, the MBR was capable of directly treating the saline produced water and simultaneously removing the BTEX and carboxylate constituents. The major challenge of the MBR system was controlling membrane fouling, particularly when the system was treating produced water under field conditions.
34

Forecasting water resources variables using artificial neural networks /

Bowden, G. J. January 2003 (has links) (PDF)
Thesis (Ph.D.)--University of Adelaide, School of Civil and Environmental Engineering, 2003. / "February 2003." Corrigenda for, inserted at back. Includes bibliographical references (leaves 475-524 ).
35

Culture du saumon de l'Atlantique Salmo salar en eau salée dans l'estuaire du St-Laurent, Québec (Canada) avec hivernage en eau douce /

Saint-Gelais, Sylvain, January 1986 (has links)
Mémoire (M.Sc. pures) --Université du Québec à Chicoutimi, 1986. / Document électronique également accessible en format PDF. CaQCU
36

Effect of salinity on biodegradation of MSW in bioreactor landfills /

Al-Kaabi, Salem. January 1900 (has links)
Thesis (Ph.D.) - Carleton University, 2007. / Includes bibliographical references (p. 248-258). Also available in electronic format on the Internet.
37

Geomechanical analysis applied to geological carbon dioxide sequestration, induced seismicity in deep mines, and detection of stress-induced velocity anisotropy in sub-salt environments /

Lucier, Amie Marie. Zoback, Mark D. January 1900 (has links)
Thesis (Ph. D.)--Stanford University, 2008. / Submitted to the Department of Geophysics. Copyright by the author.
38

Interactive effects of a calcium and magnesium sulphate enriched waste water on crop growth and nutrition

Strohmenger, Petronella Hermina Elizabeth 30 March 2006 (has links)
The coal industry of Mpumalanga Province is faced with the problem of developing cost effective ways of using large volumes of calcium and magnesium sulphate enriched waste waters. Use of the waste waters for agricultural production may contribute as a stabilising factor with regard to yields in this high potential agricultural area. The objectives of this study were to determine the effect of such waste waters on yield and to compare crop response to calcium and magnesium sulphate salinity at different nutrient levels. Two separate glasshouse experiments were conducted. Wheat (Triticum aestivum L. cv. SST 825) was grown in calcium and magnesium sulphate salinised nutrient solutions (Ca:Mg 2: 1) with differential levels of NO3, NH4, P and K. A soil pot experiment was subsequently conducted with maize (Zea mays, cv. PAN 6256), three gypsum and magnesium sulphate salinity levels and a 6 x 2 x 3 factorial combination of N, P and K. Calcium and magnesium sulphate salinity decreased the biomass production of both crops. This was mainly due to interactions of Mg with the uptake of essential nutrients in wheat and a Mg toxicity andlor Ca deficiency induced by high levels of Mg andlor SO4 in maize. The application of NO3, NH4, and K at rates different from the level considered beneficial for non-saline conditions improved wheat growth under sulphate saline conditions. Strongly inhibitory salinity levels controlled the maize yield of the highest salinity treatment regardless of the level of fertiliser application. A beneficial effect of higher NH4 supply was observed in both experiments. This can be ascribed to the antagonistic effect that NH4 exerted on Mg concentrations in plants (both experiments) and SO4 (soil pot experiment) and/or to a higher N-utilization efficiency where N was supplied as NH4 compared to NO3. Differential application levels of P had no effect on the yield of wheat. Phosphorus concentrations in maize were marginal to low, even at extremely high soil Bray I-P levels. This was probably caused by the precipitation of P as insoluble calcium phosphate complexes in the soil andlor between the free space of the cortex cells of plant roots. These results could also indicate that the Bray I extraction method does not give a true reflection of plant available P in sulphate saline soil. Further experimentation is needed to verify these results under field conditions and determine the optimal rate, method and timing of especially NH4 and PO4 fertilisers when irrigating crops with these calcium and magnesium sulphate enriched waste waters. / Dissertation (MSc (Plant Production and Soil Science))--University of Pretoria, 2007. / Plant Production and Soil Science / unrestricted
39

Investigation of marine components of large direct seawater intake & brine discharge systems for desalination plants, towards development of a general design approach

Le Roux, Maria 03 1900 (has links)
Thesis (MScEng (Civil Engineering))--University of Stellenbosch, 2010. / ENGLISH ABSTRACT: This investigation focused on the marine components of large direct seawater intake and brine discharge systems for seawater desalination plants, with the main aim to provide an overall design approach for these components. Due to its complexity, an overall and systematic design approach, addressing all the components (feedwater requirements, plant technology, marine structures and environmental issues) is required to ensure an optimum design. A literature review was done on the various desalination technologies, the main components of a seawater desalination plant, as well as the physical, hydraulic, operational and environmental issues regarding seawater extraction facilities, marine pipelines and discharge structures (diffuser). In order to obtain practical input to the development of an overall design approach, information regarding the marine structures of ten of the largest existing seawater desalination plants throughout the world were obtained and compared with each other and the available technologies. By way of example, the recently designed marine components of a new seawater reverse osmosis desalination plant in Namibia were reviewed and, as part of this thesis, alternative conceptual concepts which will include two additional components (sump and brine reservoir) were designed. The alternative design was compared with the actual design in order to determine the feasibility of the alternative in terms of operation and cost and subsequently provide input to the overall design recommendations. Furthermore, from the literature review it seems that there are still significant uncertainties regarding the required performance of a brine (dense) outfall and this required more attention in terms of environmental and hydraulic performance. Based on the Namibian plant, the diffuser configuration was analysed in terms of its hydraulic and environmental performance and subsequently some general guidance with specific respect to a brine diffuser was developed, which in turn formed part of the overall design approach for the marine components. Finally, the design approach for seawater intake structures, brine outfalls and the connecting marine pipelines is provided in the form of flow diagrams. / AFRIKAANSE OPSOMMING: Hierdie ondersoek handel oor die mariene komponente van groot en direkte toevoer van seewater en die sout-uitvloeisisteme van ontsoutingsaanlegte van seewater. Die doel is om ‘n oorsigtelike ontwerpbenadering vir hierdie component te verskaf. As gevolg van die kompleksiteit, is ‘n oorsigtelike en sistimatiese benadering, wat al die komponente (vereistes vir toevoerwater, tehnologie by die aanleg, mariene omstandighede en omgewingsfaktore) in ag neem noodsaaklik om die beste ontwerp te verseker. ‘n Literêre oorsig is gedoen ten opsigte van die tegnologie van verskeie ontsoutingsmetodes, die hoofkomponente van ‘n seewater-ontsoutingsaanleg, asook die fisiese, hidrouliese, operasionele en omgewingskwessies rakende die fasiliteite om die seewater te onttrek, die mariene pyplyne en die strukture vir die afvloei. Ten einde die optimum ontwerp te ontwikkel, is inligting oor die tegnologie en strukture van tien van die grootste bestaande onsoutingsaanlegte in die wêreld bekom, bestudeer en vergelyk Hulle is met mekaar vergelyk, asook met beskikbare tegnologie. As ‘n voorbeeld is die nuut ontwerpte mariene komponente van die nuwe ontsoutingsaanleg in Namibië, waar ontsouting d.m.v. omgekeerde osmose gedoen word ondersoek en as deel van hierdie tesis, is ‘n alternatiewe konsep, wat twee bykomende komponente – ‘n opvangput en reservoir vir die afloop – ontwerp. Hierdie alternatiewe ontwerp is met die werklike aanleg vergelyk om die uitvoerbaarheid van die onderneming en die koste daaraan verbonde te toets. Dit is gebruik as aanbeveling vir die oorhoofse ontwerp. Uit die literêre oorsig blyk dit dar daar nog groot onsekerheid is oor die vereistes van die (digte) waterafloop en dat meer aandag aan die omgewings- en hidrouliese aspekte gegee moet word. Met die Namibiese aanleg as voorbeeld, is die struktuur van die spreiers t.o.v. hidrouliese werkverrigting en die omgewing ontleed. Voortspruitend daaruit is algemene riglyne vir ‘n spesifieke spreier vir afloopwater ontwikkel, wat op sy beurt weer deel vorm van die oorhoofse ontwerp vir mariene komponente. Laastens is die ontwerp vir die strukture vir seewater-invloei, die afloopwater en die mariene verbindingspyplyne as vloeidigramme aangetoon.
40

Effets des diètes salées sur l'équilibre hydrominéral et l'acclimatation à l'eau salée de l'omble de fontaine (Salvelinus fontinalis) /

Angers, Bernard. January 1992 (has links)
Mémoire (M.Sc.B.) -- Université du Québec à Chicoutimi, 1992. / Document électronique également accessible en format PDF. CaQCU

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