• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 158
  • 151
  • 34
  • 26
  • 22
  • 10
  • 7
  • 6
  • 5
  • 4
  • 4
  • 3
  • 3
  • 3
  • 3
  • Tagged with
  • 535
  • 120
  • 105
  • 70
  • 59
  • 52
  • 49
  • 49
  • 48
  • 47
  • 47
  • 35
  • 34
  • 32
  • 28
  • 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.
61

Société Royale de médecine et eaux minérales ...

Pascal, Joseph François Jacques, January 1934 (has links)
Thèse--Faculté de médecine de Paris. / Bibliographie.
62

The biotechnology of high rate algal ponding systems in the treatment of saline tannery wastewaters

Dunn, Kevin Matthew January 1998 (has links)
Salinisation has been identified as a major cause of the progressive deterioration in the public water system in South Africa. To deal with this problem Waste Stabilisation Ponding systems have been used by the Leather Processing Industry as zero-dischaJ;ge wastewater evaporation disposal processes in water-limited inland regions of the country. While effective in the evaporation disposal function these systems are plagued by the generation of serious odour nuisance creating intractable environmental problems relating to adjacent residential communities. High loading to ponds of organic compounds, sulphides and ammonia results in strongly reducing anaerobic conditions prevailing in early parts of pond cascades. These are characterised by bright red colours due to the predominance of purple photosynthetic bacteria. Sporadic micro algal blooms of Spirulina sp. and Dunaliella sp. had been previously noted to occur on the latter ponds in these cascades, and were associated with their conversion to facultative function, with aerobic surface layers, and a marked reduction in odour release. This research programme undertook an investigation of the microbial ecology of a tannery waste stabilisation ponding system to describe factors which give rise to these blooms, and to determine whether microalgal growth may be manipulated to achieve a reliable oxygengenerating capping of the anaerobic ponds. The predominance of near pure cultures of Spin/lina platensis was demonstrated for the blooms and factors restricting its growth in the system were described. These include the interaction of ammonia and sulphide toxic effects and laboratory studies were undertaken to show how effluent loading may be regulated to enable effective growth of the cyanobacterium. At appropriate dilutions of tannery effluent an enhancement of growth was noted, compared to growth in defined mineral medium. An investigation of this phenomenon provided preliminary evidence for organic uptake by the pond micro algae and a possible contribution to heterotrophic nutrition. The manipulation of Spirulina sp. growth in a High Rate Algal Pond raceway was undertaken in outdoor pilot plant studies and the effect of microalgal capping of the anaerobic ponds in the cascade was demonstrated by activating a recycle loop from a blooming facultative pond. Heavy metal contaminants were effectively eliminated by an optimisation of the primary anaerobic pond function and precipitation as metal sulphides. Biomass was harvested and dried, during which a range of methods were evaluated. Toxicological studies were undertaken on the dried biomass using Artemia and chick assays, and feed studies showed its useful application in rations for the abalone Haliotlls midae and rainbow trout Onchorhynchlls mykiss. Based on positive independent assessment of research outcomes, a decision was made by the tanning company operating the Waste Stabilisation Ponding system, to proceed to the construction of a full-scale 2 500 m2 High Rate Algal Pond raceway. This would be used for controlled Spirlilina biomass production to effect a practical capping of the anaerobic ponds in the system, and to evaluate its commercial potential in the feed market. The Advanced Integrated Wastewater Ponding System described by Oswald (1991) provided the conceptual basis for the Algal Biotechnology process development undertaken. The studies of the microbial ecology and the biotechnological potential of this system have shown that a Spirulina-based High Rate Algal Ponding process can be engineered in such a way that saline tannery effluents may be treated to effect a significant reduction in overall pollution load, that biomass may be recovered as a value added product of the treatment process and that the operational performance of Waste Stabilisation Ponding systems, and hence their immediate environment, may be improved by the use of the High Rate Algal Pond as a retrofitted upgrading unit operation.
63

Exploitation of non-living marine resources within national jurisdiction in East Africa

Ntola, Yamkela Siqhamo January 2015 (has links)
This dissertation involves an analysis and discussion of the legal regime governing the exploitation of non-living marine resources within national jurisdiction in East Africa. This is in light of the relatively recent offshore oil and gas discoveries off the coasts of Mozambique and Tanzania which have resulted in offshore exploration activities along the Western Indian Ocean (including the Red Sea) in pursuit of these hydrocarbons. Before delving into legal analysis and discussion, the dissertation departs by providing background on the 1982 United Nations Law of the Sea Convention (LOSC)2 which is the international legal regime governing maritime spaces and the contributions made by, inter alia, East African coastal States to bring it about. From here, the dissertation ventures into an analysis and discussion of the legal zones claimed by East African coastal States within which exploitation activities may occur. This part of the discussion involves, among other things, an in depth analysis of the practices of East African coastal States as far as establishing maritime zones in terms of international law. The dissertation then proceeds to discuss which East African coastal States have delimited their maritime zones where they overlap with neighbouring States with adjacent and/or opposite coasts. The discussion highlights which States, in terms of international law, have clearly defined the ambit of their maritime jurisdiction by establishing a delimitation boundary where claims to maritime zones overlapped. This part of the dissertation also discusses which States have not delimited their overlapping maritime zones and the reasons for the lack of delimitation. Following this, the dissertation moves on to discuss the LOSC provisions applicable to exploiting non-living resources, and analyse whether the laws of East African coastal States that pertain to exploiting these resources adequately give effect to LOSC. Finally, in light of the above analysis and discussions, the dissertation moves on to establish if whether or not the legal infrastructure of East African coastal States is adequate for exploiting non-living resources within their national jurisdiction. Generally, the findings reflect favourably on the legal framework of East African coastal States. However, the pressing issue is the practices of some States in respect of claiming certain maritime zones and where necessary, not delimiting these zones. This results in uncertainty as to the maritime jurisdiction of a coastal State, especially with resources such as oil and gas which may straddle across boundaries. Moreover, it creates conflict and as such, threatens peace and security in the region as well as stunt economic and socio-economic development. As such, this dissertation, on the one hand, reflects the advancement of East African coastal States from contributing towards the adoption and coming into effect of LOSC, as well as giving effect to it domestically as far as exploiting non-living resources within national jurisdiction is concerned. On the other hand, it highlights the work that lays ahead for East African coastal States in order for them to fully enjoy their right.
64

Variabilidade espacial e temporal da qualidade das Ãguas no trecho perenizado na Bacia HidrogrÃfica do Curu, Cearà / Spatial and temporal variability in quality of the water in the perennialized stretch of the hydraulic basin of river Curu, Ceara state, Brasil

Josà Itamar Frota JÃnior 31 August 2006 (has links)
nÃo hà / O presente trabalho foi desenvolvido com o objetivo de analisar a variabilidade espacial e temporal da qualidade das Ãguas na regiÃo perenizada da bacia hidrogrÃfica do Curu, avaliando os efeitos da aÃÃo antrÃpica e influÃncia dos tipos de solos da regiÃo. Foram avaliados os seguintes parÃmetros: cÃtions (Ca2+, Mg2+, Na+, K+), Ãnions (HCO3 - e Cl-) e demais parÃmetros: RAS, Condutividade ElÃtrica, pH e SÃlidos Dissolvidos. Foram coletadas amostras de Ãgua em nove pontos distribuÃdos ao longo do trecho perenizado da bacia do Curu, durante o perÃodo de um ano. As analises foram realizadas no LaboratÃrio de Solos e Ãgua da Universidade Federal do CearÃ. Os valores mÃdios dos parÃmetros foram avaliados em relaÃÃo a variabilidade espacial e temporal. Realizou-se a AnÃlise de VariÃncia a 5% e de comparaÃÃo das mÃdias pelo Teste de Tukey a 1% para os dados referentes à variabilidade espacial. Com relaÃÃo à variabilidade temporal foram analisados os valores mÃdios dos perÃodos seco e chuvoso para comparaÃÃo posterior dos resultados e classificaÃÃo de suas Ãguas atravÃs do Diagrama de Piper. Os resultados evidenciaram incremento de sais ao longo da bacia. No ponto 1 (Serrota-Pentecoste) o valor mÃdio encontrado para o sÃdio foi de 1,92 mmolc L-1, enquanto no ponto 9 (Fazenda Pedras-Paraipaba) foi de 3,47 mmolc L-1 . Ficou nÃtida a influÃncia antrÃpica na qualidade das Ãguas estudadas ao longo de toda a bacia, as diferenÃas mais significativas entre os parÃmetros foram observadas entre os pontos P1, P2 e P3 parte media da bacia do Curu e P8 e P9 (parte baixa da bacia do Curu), onde a partir do ponto 6, o rio recebe Ãguas de drenagem dos perÃmetros irrigados e efluentes dos esgotos. Quanto a sazonalidade, observou-se que de maneira geral houve incremento nos valores mÃdios encontrados no perÃodo chuvoso, fato justificado pelo aumento da drenagem superficial e lavagem dos sais oriundos dos perÃmetros irrigados inseridos na bacia. Com relaÃÃo à classificaÃÃo das Ãguas estudadas, as mesmas foram classificadas como cloretadas. / This research aims analyze the spatial and temporal variability in quality of the water used to perennialized area the hydraulic basin of river Curu, Ceara state, Brazil, evaluating the effects of the anthropic action and the influence of the different types of soils in the region. The following parameters were appraised: cations (Ca2+, Mg2+, Na+, K+), anions (HCO3 -, Cl-) and also: SAR, electric conductivity, pH and dissolved solids. During a period of one year, samples of water were collected in nine points distributed along the perennialized part of the basin of Curu and were analysed in the Soils and Water Laboratory at Federal University of Ceara State. Spatial and temporal variability were considered in the analysis of the medium values of the parameters. Spatial variability was appraised using the Analysis of Variance to 5% and the comparison of the averages with the Test of Tukey to 1%. Regarding the temporal variability, the medium values of the periods dry and rainy were compared and analyzed, in order to classificate waters using the Diagram of Piper. The results evidenced increment of salts along the basin. In the point 1 (Serrota-Pentecoste) the medium value found for sodium was of 1,92 mmolc L-1, while in the point 9 (Pedras Farm-Paraipaba) it was of 3,47 mmolc L-1. It was clear the anthropic influence in the quality of the water studied along the whole basin. The most significant differences in the parameters were observed among the points P1, P2 and P3 in the middle part of the basin of Curu, and P8 and P9 in the low part of the basin, where from the point 6, the river receives waters of drainage of irrigated perimeters and effluents of sewers. In respect of seasonality, an increment in the medium values was observed in the rainy period, justified for the increase of superficial drainage and wash of the salts, originated from the irrigated perimeters located in the basin. With the results of the analysis, the studied waters were classified as chlorinated.
65

The education of Frank Waters, 1902-1969 : finding a southwestern literary voice

Meyers, Thomas Duncan 28 March 2011 (has links)
Not available / text
66

A review of the use of salt water for flushing in Hong Kong : project report /

Ip, Chi-kuen. January 1900 (has links)
Thesis (M. Sc.)--University of Hong Kong, 1993.
67

Inland saline aquaculture : overcoming biological and technical constraints towards the development of an industry /

Partridge, Gavin J. January 1900 (has links)
Thesis (Ph.D.)--Murdoch University, 2008. / Thesis submitted to the Division of Science and Engineering. Includes bibliographical references (leaves 123-154).
68

Stanovení těžkých polyaromátů v odpadních vodách závodu DEZA / Determination of large polyaromatics in waste waters of DEZA factory

Trefilová, Daniela January 2009 (has links)
Large polycyclic aromatic hydrocarbons with molecular mass exceeding 278 Da are rarely object of study, in spite of the fact that some compounds from this group are proved carcinogens. These compounds belong to the group of persistent organic compounds and they are considered as dangerous environmental contaminants. Diploma thesis is focused on the evaluation of the occurence of large PAHs in technological and waste waters produced in black pitch processing in the DEZA Valašské Meziříčí factory. The method of their analysis based on reversed-phase liquid chromatography with non-aqueous gradient; UV-VIS and fluorescence detection will be used. This method will enable the study of changes of large PAHs distribution at various stages of waste water treatment process.
69

Estudo sobre a aplicaÃÃo da espectrofotometria derivativa na anÃlise de nitrogÃnio em diversas matrizes de Ãguas / Study on the application in derivative spectrophotometry analysis of nitrogen in several matrices of waters

Maria do Socorro Pinheiro da Silva 19 July 2013 (has links)
A determinaÃÃo dos nÃveis de nitratos e nitrogÃnio total (NT) em Ãguas constitui uma ferramenta importante no sentido de avaliar o controle de seus nÃveis para proteÃÃo da saÃde humana bem como para caracterizar a eutrofizaÃÃo dos corpos aquÃticos. O presente trabalho faz um estudo da espectrofotometria derivativa (ED) para determinaÃÃo de nitratos e NT pelo mÃtodo zero-pico por ED, em segunda derivada, no mÃximo de absorÃÃo do nitrato (225nm). Neste estudo foram avaliados os interferentes comumente encontrados nas matrizes onde a metodologia foi aplicada, que foram Ãguas minerais, Ãguas adicionadas de sais e Ãguas superficiais (aÃudes e rios): bicarbonato, carbonato, ferro, cobre, sulfato, cloreto, brometo, iodeto, fosfato, sulfato, nitrito e matÃria orgÃnica dissolvida (MOD). Esta metodologia foi aplicada na determinaÃÃo de nitratos em amostras Ãguas minerais, adicionada de sais e Ãguas de aÃudes monitorados pela COGERH, onde nesta Ãltima matriz foi determinado tambÃm NT. Os interferentes avaliados nÃo apresentaram interferÃncia na segunda derivada do nitrato dentro de limites aceitÃveis, com exceÃÃo dos Ãons nitrito e carbonato, onde foi necessÃrio a remoÃÃo destes pela adiÃÃo de uma soluÃÃo de Ãcido sulfÃmico com HCl. Segundo o teste t (student) pareado, para amostras de Ãguas minerais e adicionadas sais, que foram analisados os teores de nitratos tanto por ED quanto pelo mÃtodo da reduÃÃo em coluna de cÃdmio com posterior determinaÃÃo pelo mÃtodo da sulfanilamida, nÃo apresentaram diferenÃas significativas a um nÃvel de confianÃa de 95%. Para as amostras de Ãguas superficiais, a determinaÃÃo de nitratos por ED demonstrou nÃo ser aplicÃvel. JÃ determinaÃÃo de NT demonstrou-se promissora, porÃm, estudos preliminares sugerem que a MOD presente nas amostras dos aÃudes estudados apresenta interferÃncia espectral, uma vez que, tais aÃudes estudados apresentaram indÃcios de contaminaÃÃo de origem alÃctone, se encontrando, na maioria, eutrofizados. / The determination of the levels of nitrates and total nitrogen (TN) in water is an important tool to assess the control levels for the protection of human health as well as to characterize the eutrophication of water bodies. The present work is a study of derivative spectrophotometry (DS) for the determination of nitrate and TN zero-peak method for DS in the second derivative maximum absorption of nitrate (225nm). In this study we evaluated the interferences commonly found in matrices where the methodology was applied, which were mineral water, added salts and surface water (reservoirs and rivers): bicarbonate, carbonate, iron, copper, sulfate, chloride, bromide, iodide, phosphate, sulphate, nitrite and dissolved organic matter (DOM). This methodology was applied in the determination of nitrate in mineral water samples, added salt and water reservoirs monitored by COGERH where the latter matrix was also determined TN. The interfering evaluated showed no interference in the second derivative of nitrate within acceptable limits, with the exception of nitrite and carbonate ions, where it was necessary to remove these by adding a solution of sulfamic acid with HCl. According to the t test (student) paired samples of mineral waters and added salts, which were analyzed nitrate levels both DS as the method of cadmium reduction column with subsequent determination by the method of sulfanilamide, showed no significant differences a confidence level of 95%. For surface water samples, the determination of nitrates by DS proved not to be applicable. Determination of TN already proved to be promising, however preliminary studies suggest that the DOM present in the samples studied the reservoirs presents spectral interference, since such, dams studied showed signs of contamination of allochthonous origin, lying mostly eutrophic.
70

Optimization of culture conditions and extraction method for phycocyanin production from a hypersaline cyanobacterium

Mogany, Trisha 08 August 2014 (has links)
Submitted in fulfilment of the requirements of the degree of Master of Technology: Biotechnology, Durban University of Technology, 2014. / Cyanobacteria contain phycocyanin a light harvesting pigment found to have numerous biotechnological applications, such as: a natural colorant in food and cosmetics, fluorescent tags employed in clinical and immunological research and also in therapeutic processes. Successful phycocyanin production depends on growth characteristics, ability to accumulate high quantities of the pigment, and an effective downstream process. Therefore, the aim of this research was to optimize the extraction method and production by determining the optimal cultivation conditions for phycocyanin producing cyanobacterium. This cyanobacterium was isolated from a hypersaline water body in Kwa-Zulu Natal, and subsequently purified using traditional streak and spread plate techniques. Different cell disruption techniques and a range of buffers were evaluated for the extraction of phycocyanin. The buffer concentrations and pH was subsequently optimized. Results showed that maximum phycocyanin was extracted when cells were suspended in 50mM sodium phosphate buffer (pH-7.5) supplemented with 10 % lysozyme and then disrupted using the freeze–thaw method at -20 & 4°C. The UV-Vis absorption spectral scan of the crude extracted pigments showed a peak at 620 nm. This corresponds to phycocyanin production. Unwanted proteins were removed using a 25and 50% saturated ammonium sulphate precipitation, followed by dialysis. SDS-PAGE showed two subunits with molecular masses of 19 and 20 kDa. These masses corresponded to phycocyanin α and β subunits. Furthermore, a food grade purity ratio (A615/A280) of 1.20 was achieved. The effects of various abiotic factors (temperature, light and pH) on growth and phycocyanin production of the Cyanothece sp. was investigated. Temperature ranging from 20-45°C and pH (5-10) was evaluated for 2 weeks. Cultures were then subjected to four photoperiods (24:0, 18:06 12:12 and 8:16 h light: dark) three light intensities (25, 75 and 125 µmol photons per m2 per –s) at varying wavelengths i.e. blue, red and green and Grolux light. Ideal conditions were observed at 35°C, 125 µmol photons.m2.s-1 of Grolux light for a 16:8 light and dark photoperiod. It was observed that the highest biomass and phycocyanin production was found to be at 35°C, temperatures below or above resulted in a decrease in both growth and pigment synthesis. Phycocyanin concentration changed in response to light quality and intensity. A significantly higher (p<0.05) phycocyanin yield was found when the culture was exposed to 125 µmol photons.m2.s-1 of Grolux light compared with the other three light conditions. Using Design of experiments, a series of fractional factorial experiments were carried out to optimize media components for pigment production. The final optimized growth medium was determined from a central composite design using response surface plots together with a mathematical point-prediction tool and consisted of 2g/L NaNO3, 0.06g/L K2HPO4, 0.12 g/L MgSO4.7H2O, 0.033 g/L CaCl2.2H2O, 100g/L NaCl, 12mL minor nutrients and 0.5 trace metal. A 72 % increase in phycocyanin was observed. This research revealed that this particular Cyanothece sp. shows great potential as a reliable source of phycocyanin.

Page generated in 0.0807 seconds