Дисертації з теми "Seawater study"
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1
Reed, Jason. "Grower Attitudes Towards Water Management Strategies While Mitigating Seawater Intrusion| A Case Study of the Castroville Seawater Intrusion Project." Thesis, San Jose State University, 2017. http://pqdtopen.proquest.com/#viewpdf?dispub=10635156.
Повний текст джерелаАнотація:
The Salinas River Valley Watershed has endured the effects of seawater intrusion for decades caused by overpumping groundwater from the Salinas River Groundwater Basin. The Castroville Seawater Intrusion Project began delivering recycled water in 1998 with other water sources due to wells becoming too saline. One-on-one, in-person interviews with eighteen growers, who own or lease farmland within the Project’s service area, were conducted during a severe, statewide drought. Interview questions explored grower attitudes and concerns regarding their water supply, and the impact of management strategies on the mitigation of seawater intrusion. Two research questions were posed, exploring factors that influence grower acceptance of alternative water supplies, and whether environmental impacts affect their attitudes. Four prominent factors were found that influence grower acceptance of alternative water supplies: perceived need for water supply, changes to cost and/or water quality, information/education, and level of trust. The study also revealed three motivations of growers for choosing water supplies that do not increase seawater intrusion or contribute to adverse environmental impacts: protecting harvest/land, managing associated cost of operations, and avoiding increased regulations and/or oversight. Growers with fewer numbers of farms and smaller acreage of farmland tended to have a greater perceived need to acquire sustainable water supplies, while being more reluctant to implement water sources of lesser quality.
2
Bin, Marshad Saud Mohammed H. "Economic evaluation of seawater desalination : a case study analysis of cost of water production from seawater desalination in Saudi Arabia." Thesis, Heriot-Watt University, 2014. http://hdl.handle.net/10399/2996.
Повний текст джерелаАнотація:
As a result of the increasing scarcity of freshwater resources worldwide, many countries have resorted to the use of unconventional sources, of which seawater desalination is the most significant, for meeting the supply-demand gap. However, despite the recorded advances in desalination technologies of recent decades, desalination remains a very expensive operation and operators will be greatly assisted if reliable means of predicting the costs are available to aid effective decision making during planning of new plants or the operation of existing plants. To achieve this, it is important to fully understand the factors that contribute to desalination costs, which could then be used to develop appropriate models for predicting costs that can support budgeting and/or cost reductions decision making. Consequently, this project has investigated the development of such models for predicting monthly production costs using data from 16 operational plants in Saudi Arabia. Monthly and annual data spanning 2001 – 2010 were collected on total water production, type of desalination technique, sea water salinity, product water salinity, energy consumption, and total (capital and operational) unit cost of water production. Because of the way in which the data were archived, some of the variables only had the annual totals for some of the years, which made them unsuitable for the monthly scale adopted for the analyses. Consequently, disaggregation schemes based on several variants of the method of fragments widely used in hydrological studies were used to obtain monthly data from the annual data. Exploratory analysis showed that the monthly costs correlated most with the total water production, which then formed the lone independent variable for various tested regression model formulations. In general, an inverse regression model performed best during both calibration and validation. To enhance the usefulness of the predictive model for decision making, uncertainty limits of the predictions were constructed using a Monte Carlo simulation approach involving the seasonal, lag-1 autoregressive generation of equally likely realisations of the available historic records that have been transformed to remove the skewness. Extensive testing of the data generation technique showed that the assumed lag-1 auto-regressive dependence structure was adequate. This study thus provides for the first time a predictive model for costs of desalination in Saudi Arabia and its uncertainty range for effective budgeting and operational management. Although the models were developed using Saudi Arabia data, the fact that only one independent variable was used means that the replication of the methodology in other desalination-intensive countries can be readily carried out.
3
Buckley, P. J. M. "Organic speciation of copper, zinc and lead in seawater : A comparative study using electrochemical and ion exchange methods." Thesis, University of Liverpool, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.354547.
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4
Persson, Söderman Jennie. "A Study of the Short-term Variability of Seawater pCO2 near Östergarnsholm." Thesis, Uppsala universitet, Luft-, vatten och landskapslära, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-222286.
Повний текст джерелаАнотація:
In this study, an analysis of upwelling and biological activities impact on the seawater pCO2 variability was done to improve the knowledge about the pCO2 variability in seawater in the Baltic Sea. During upwelling activity, CO2 rich waters are upwelled to the surface. This influences air-sea CO2 flux and thus the net uptake/emission of CO2 by the sea. pCO2 and SST measurements from a SAMI sensor, located at the Östergarnsholm site in the Baltic Sea, and SST satellite data, was used to identify periods affected by upwelling activity. A strong variability due to upwelling activity was observed on the pCO2 concentration. The frequency of upwelling activity at the Östergarnsholm site was estimated to be around 20 % of the time from May-November. The relationship between pCO2 and SST during upwelling activity was found to depend of the month. In November, this relationship can be used to characterise the effect of upwelling, but for the other months there are no differences between the none- upwelling periods and the upwelling periods. Another type of period, characterized by a diurnal variability of pCO2 mainly driven by the biological effect, was also observed.I denna studie undersöktes hur uppvällning och biologisk aktivitet påverkar koncentrationen av pCO2 i havet. Detta gjordes för att få ökad förståelse för korttidsvariationen av pCO2 i Östersjön. Under uppvällning pressas CO2-rikt vatten upp till ytan. Detta påverkar flödet av CO2 mellan hav och atmosfär och då även det totala upptaget/utsläppet av CO2 från havet. I studien användes pCO2 och SST mätningar från en SAMI-sensor, placerad vid Östergarnsholm i Östersjön, och en del satellitdata för att identifiera perioder påverkade av uppvällning. Det observerades att uppvällnings inverkan på koncentrationen av pCO2 varierar kraftigt. Frekvensen av uppvällning vid Östergarnsholm uppskattades vara ungefär 20 % av tiden under maj-november. Relationen mellan SST och pCO2 under perioder med uppvällning observerades variera från maj-november. I november kan denna relation användas till att uppskatta effekten av uppvällning men under de andra månaderna är relationen under uppvällning för lika relationen under icke- uppvällning. Även en annan slags perioder observerades; under dessa perioder observerades en dygnscykel av pCO2, driven av biologisk aktivitet.
5
Xu, Yongfu. "A study of the biogeochemical cycle of COâ†2 in the ocean using a parcel model." Thesis, University of East Anglia, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.256896.
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6
Fishwick, Matthew Paul. "A study of the dissolution of atmospherically derived trace metals into North Atlantic seawater." Thesis, University of Plymouth, 2016. http://hdl.handle.net/10026.1/5288.
Повний текст джерелаАнотація:
The aim of this study was to investigate the factors that affect the dissolution of a suite of trace metals from aerosols into seawater from wet and dry deposition, with a focus on important trace metals: manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu) and lead (Pb). To this end, aerosol and rainwater samples were collected from Tudor Hill (Bermuda) and Penlee Point (Cornwall) atmospheric observatories and surface seawater samples were collected from the Sargasso Sea and the Celtic Sea. These representative aerosol, rainwater and seawater samples were used in aerosol leaching and rainwater mixing experiments, which simulated the processes of mixing and trace metal dissolution following wet and dry deposition as closely as possible within the laboratory. Key variables were changed to investigate the effect of aerosol source/composition, seawater temperature, pH, dissolved oxygen concentration and organic ligand amendments on aerosol and rainwater trace metal dissolution. Results for aerosol leaching experiments revealed that changes to key physico-chemical conditions had little effect on the amount of Mn, Fe, Co, Ni and Pb leached from aerosols and therefore plausible future changes in ocean surface temperature, pH and oxygenation are unlikely to affect the flux of these important trace metals to surface waters. Conversely, aerosol source and composition had a significant effect on the dissolution of aerosol Fe, Co and Pb, with the most anthropogenically influenced aerosol samples displaying the highest solubilities. Therefore, future changes in land use and fossil fuel combustion are likely to affect the flux of these metals to the surface ocean. Fractional solubilities were in the range of 50 – 104% for Mn, 0.3 – 3.2% for Fe, 29 – 58% for Co, 40 – 85% for Ni and 67 – 112% for Pb. In addition, novel empirical relationships were found between the fractional solubilities of Fe, Co and Pb and enrichment factors for antimony, vanadium, Ni and Cu. This suggests that these fractional solubilities in seawater could be predicted using only total aerosol trace metal concentrations. The use of ultrafiltration provided unique insight into the size fractionation (colloidal 0.02 – 0.4 μm; soluble < 0.02 μm) of dissolved aerosol trace metals and showed Fe and Pb were mostly colloidal (77 – 98% colloidal), Mn and Co were mostly soluble (0 – 48% colloidal) and Ni showed a mixed profile (6 – 58% colloidal) when released from aerosols into ambient seawater. However, in the presence of a sufficient concentration of strong organic ligands the majority colloidal Fe was converted to soluble Fe (up to 100% soluble). Some of these organic ligands were also able to increase the soluble fraction of dissolved aerosol Mn. Similarly, the presence of organic ligands in rainwater maintained Mn, Fe, Co, Cu and Pb in the dissolved phase following delivery by rain into seawater. Rainwater ligands had no effect on the typically varied size fractionation profile of Mn, Fe, Co and Cu in rainwater mixed with seawater, UV-irradiation of rainwater, however, shifted the size fractionation of Pb in rainwater/seawater mixtures from 80 – 100% colloidal to 13 – 63% soluble, indicating that Pb-binding rainwater ligands are either colloidal or attached to colloidal matter. These findings highlight the importance of organic ligands in rainwater and seawater for retaining trace metal micronutrients and toxicants in the surface ocean, with implications for primary production.
7
Abd-Elhamid, Hany Farhat. "A simulation-optimization model to study the control of seawater intrusion in coastal aquifers." Thesis, University of Exeter, 2010. http://hdl.handle.net/10036/3054.
Повний текст джерелаАнотація:
Groundwater contamination is a very serious problem as it leads to the depletion of water resources. Seawater intrusion is a special category of groundwater contamination that threatens the health and possibly lives of many people living in coastal areas. The focus of this work is to develop a numerical model to study seawater intrusion and its effects on groundwater quality and develop a control method to effectively control seawater intrusion. Two major approaches are used in this study: the first approach is the development of a finite element model to simulate seawater intrusion; the second is the development of a simulation-optimization model to study the control of seawater intrusion in coastal aquifers using different management scenarios. The simulation-optimization model is based on the integration of a genetic algorithm optimization technique with the transient density-dependent finite element model developed in this research. The finite element model considers the coupled flow of air and water and solute transport in saturated and unsaturated soils. The governing differential equations include two mass balance equations of water and air phases and the energy balance equation for heat transfer, together with a balance equation for miscible solute transport. The nonlinear governing differential equations are solved using the finite element method in the space domain and a finite difference scheme in the time domain. A two dimensional finite element model is developed to solve the governing equations and provide values of solute concentration, pore water pressure, pore air pressure and temperature at different points within the region at different times. The mathematical formulation and numerical implementation of the model are presented. The numerical model is validated by application to standard examples from literature followed by application to a number of case studies involving seawater intrusion problems. The results show good agreement with previous results reported in the literature. The model is then used to predict seawater intrusion for a number of real world case studies. The developed model is capable of predicting, with a good accuracy, the intrusion of seawater in coastal aquifers. In the second approach, a simulation-optimization model is developed to study the control of seawater intrusion using three management scenarios: abstraction of brackish water, recharge of fresh water and combination of abstraction and recharge. The objectives of these management scenarios include minimizing the total costs for construction and operation, minimizing salt concentrations in the aquifer and determining the optimal depths, locations and abstraction/recharge rates for the wells. Also, a new methodology is presented to control seawater intrusion in coastal aquifers. In the proposed methodology ADR (abstraction, desalination and recharge), seawater intrusion is controlled by abstracting brackish water, desalinating it using a small scale reverse osmosis plant and recharging to the aquifer. The simulation-optimization model is applied to a number of case studies. The efficiencies of three different scenarios are examined and compared. Results show that all the three scenarios could be effective in controlling seawater intrusion. However, ADR methodology can result in the lowest cost and salt concentration in aquifers and maximum movement of the transition zone towards the sea. The results also show that for the case studies considered in this work, the amount of abstracted and treated water is about three times the amount required for recharge; therefore the remaining treated water can be used directly for different proposes. The application of ADR methodology is shown to be more efficient and more practical, since it is a cost-effective method to control seawater intrusion in coastal aquifers. This technology can be used for sustainable development of water resources in coastal areas where it provides a new source of treated water. The developed method is regard as an effective tool to control seawater intrusion in coastal aquifers and can be applied in areas where there is a risk of seawater intrusion. Finally, the developed FE model is applied to study the effects of likely climate change and sea level rise on seawater intrusion in coastal aquifers. The results show that the developed model is capable of predicting the movement of the transition zone considering the effects of sea level rise and over-abstraction. The results also indicate that the change of water level in the sea side has a significant effect on the position of the transition zone especially if the effect of sea level rise is combined with the effect of increasing abstraction from the aquifer.
8
Moollye, Sun Veer. "A Comparative Study on the Seawater Quality of the Coral Environment between Miri (Sarawak) and Sipadan (Sabah)." Thesis, Curtin University, 2017. http://hdl.handle.net/20.500.11937/59024.
Повний текст джерелаАнотація:
This study created a baseline for the seawater quality at Miri (Sarawak) and compared it to that of Sipadan (Sabah). Three locations in the Miri-Sibuti Coral Reef National Park were chosen and sampled during summer, transition period and monsoon at three depths. Two sites with the same attributes were chosen and sampled during monsoon at Sipadan. Physical parameters, nutrients, major ions, and trace metals were studied together with photo-documentation of the corals.
9
Singla, Milà Mireia. "Study of microplastics role in seawater based on collected samples across the oceans during the Barcelona World Race 2015." Doctoral thesis, Universitat Ramon Llull, 2020. http://hdl.handle.net/10803/669954.
Повний текст джерелаАнотація:
Els microplàstics s’han convertit en un gran problema mediambiental. La sobreproducció i l’ús excessiu del plàstic ha dificultat el seu correcte tractament y això provoca que sigui el sector amb un major creixement en la generació de residus. Els residus plàstics, a través de diversos processos es degraden i es trenquen en partícules mes petites donant lloc als microplàstics. També es poden trobar un altre tipus de microplàstics, aquells originats i fabricats d’aquesta mida de forma intencionada. Tot i que s’han publicat diversos articles científics demostrant la presencia de microplàstics a zones mol localitzades, cap d’ells mostra una visió global sobre aquest problema mediambiental.
En aquesta tesis presentem el desenvolupament d’una nova metodologia de mostreig de microplàstics a més de la retenció d’altres contaminants orgànics suspesos en l’aigua de mar. Per això, hem col·laborat amb la Fundació de Navegació Oceànica de Barcelona (FNOB), entitat organitzadora de la Barcelona World Race (BWR) y amb el grup Sailing Technologies. A través d’aquesta col·laboració, hem desenvolupat un dispositiu de mostreig instal·lat en un dels vaixells participants en la BWR 2015 que es capaç de col·lectar microplàstics i contaminants orgànics en aigua superficials en varies localitzacions del mon passant per quatre oceans (Mar Mediterrani i Oceans Atlàntic, Pacífic e Índic).
Hem realitzat la caracterització dels microplàstics mostrejats durant la BWR 2015. L’anàlisi de la seva morfologia, composició i distribució ens ha permès conèixer el nivell de contaminació i l’impacte de tenir aquest tipus de micropartícules en els oceans. També hem demostrat el efecte concentrador dels microplàstics. Hem desenvolupat un mètode analític reproduïble per l’extracció i quantificació de varies famílies de contaminants orgànics de diferents tipus de micropartícules polimèriques.
Per últim, es desenvolupa una metodologia per l’elució dels cartutxos SPE utilitzats durant la BWR 2015. A més, s’ha realitzat un anàlisis PCA i s’han agrupat les mostres en funció de diferents paràmetres com les corrents, la localització o la seva posició respecte l’equador.
En conclusió, aquesta tesis proporciona informació sobre l’estat global dels oceans en relació als microplàstics i les seves conseqüències. L’estudi del efecte dels microplàstics en els oceans de forma global ajuda a comprendre la situació mediambiental actual.Los microplasticos se han convertido en un gran problema medioambiental. La sobreproducción y el uso excesivo del plástico ha dificultado mucho su tratamiento y esto provoca que sea el sector con un mayor crecimiento en la generación de residuos. Los desechos plásticos, a través de varios procesos se degradan o rompen en partículas más pequeñas dando lugar a los microplasticos. También se pueden encontrar otro tipo de microplasticos, esos originados y fabricados en ese tamaño de forma intencionada. Aunque ya se han publicado varios artículos científicos demostrando la presencia de microplasticos en zonas localizadas, ninguno de ellos muestra una visión global acerca de este problema medioambiental. En esta tesis presentamos el desarrollo de una nueva metodología de muestreo de microplásticos además de la retención de otros contaminantes orgánicos suspendidos en agua de mar. Para ello, hemos colaborado con la Fundación de Navegación Oceánica de Barcelona (FNOB), entidad organizadora de la Barcelona World Race (BWR) y con el Grupo Sailing Technologies. A través de esta colaboración, hemos desarrollado un nuevo dispositivo de muestreo instalado en uno de los barcos participantes en la BWR 2015 que es capaz de colectar microplasticos y contaminantes orgánicos de agua superficial en varias localizaciones del mundo pasando por cuatro océanos (Mar Mediterráneo y Océanos Atlántico, Pacífico y Índico). Hemos realizado la caracterización de los microplasticos muestreados durante la BWR 2015. El análisis de su morfología, composición y distribución nos ha permitido conocer el nivel de contaminación y el impacto de tener este tipo de micropartículas en los océanos. También hemos demostrado el efecto concentrador que poseen los microplasticos. Hemos desarrollado un método analítico reproducible para la extracción y cuantificación de varias familias de contaminantes orgánicos de distintos tipos de micropartículas poliméricas. Por último, se desarrolla una metodología para la elución de los cartuchos SPE usados en la BWR 2015. Además, se ha realizado un análisis PCA y se han agrupado las muestras en función de varios parámetros como las corrientes, la localización o su posición respecto al ecuador. En conclusión, esta tesis proporciona información sobre el estado global de los océanos en relación con los microplasticos y sus consecuencias. El estudio del efecto de los microplasticos en los océanos de forma global es de ayuda para comprender la situación medioambiental actual.
Microplastics have become a huge environmental concern in recent years. The overproduction and excessive use of plastic have made difficult a proper manage and that is why it has become the fastest growing segment of the waste stream. Plastic debris, through several physical, chemical and biological processes can degrade or breakdown resulting in microplastics. In addition to these it can also find other type of microplastics which are those originally and intentionally manufactured in that size. Although several research studies have been published demonstrating the presence of microplastics in localised coastal regions, any of them show a global scenario about this environmental concern. Here we present the development of a new methodology for microplastics sampling and retention of pollutants present in seawater. In this sense, we have collaborated with the Barcelona World Race (BWR) organization and the “Fundació de Navegació Oceànica de Barcelona” (FNOB). Throughout this collaboration, we have developed a device, named COA device, installed in a racing boat of the BWR 2015 which collects microplastics and pollutants on superficial seawater from the different locations of the world going through four oceans (Mediterranean Sea and Atlantic, Pacific and Indian Oceans). Furthermore, we performed the characterization of the microparticles collected during the BWR 2015. The analysis, based on microscopic techniques, of their morphology, composition and distribution has allowed us to know better the level of pollution of the marine environment and which is the global impact of having that particles in the oceans. In addition to that, we demonstrate the microplastics concentration effect of persistent organic pollutants. We also developed a reproducible analytical methodology based on a new approach for the release and quantification of different families of pollutants from polymeric microparticles. Finally, different analytical methods have been optimized for the analysis of several pollutants solved in seawater. The elution of pollutants retained in the SPE cartridges used in the BWR 2015 has been performed. In conclusion, this thesis provides information about the overall status of the oceans in terms of microplastics and their consequences at present. The study of the role of microplastics in seawater in a global way have been helpful to understand the actual environmental situation.
10
McWilliam, Iain Stuart. "Development of microarray techniques for the study of gene expression in the European eel (Anguilla anguilla) during silvering and migration to seawater." Thesis, St Andrews, 2008. http://hdl.handle.net/10023/502.
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Robertson, Jane Isabella. "The coulometric determination of total inorganic carbon in seawater and the study of the inter-relationship between the planktonic metabolism of carbon dioxide and oxygen." Thesis, Bangor University, 1989. https://research.bangor.ac.uk/portal/en/theses/the-coulometric-determination-of-total-inorganic-carbon-in-seawater-and-the-study-of-the-interrelationship-between-the-planktonic-metabolism-of-carbon-dioxide-and-oxygen(bb8e93ac-5197-474e-a930-021d1b5358f4).html.
Повний текст джерелаАнотація:
A microprocessor- controlled coulometric system for measuring total inorganic carbon in seawater samples was refined. A precision of 0.5 micromoles/kg (one standard error) from a single sample was routinely achieved in the laboratory. This was reduced to 1.0 micromoles/kg at sea due to an increase in the instrument blank. The system has proved to be a robust and reliable method, well suited for routine plankton productivity measurements and oceanic mapping. The coulometric technique was used in conjunction with an automated Winkler oxygen method to make in vitro and in situ observations of planktonic photosynthetic ana respiratory quotients. In common wi th earlier published observations, a wide range of quotients were obtained. A detailed consideration of analytical and sampling errors led to the conclusion that the quotients could mostly be explained by the stoichiometry of conventional biochemical products and reactants. In situ observations were carried out within mesoCosms:-Tn one field study, particular attention was paid to the correction of data for physical mixing within the mesocosm and exchange with the atmosphere. A dye diffusion study coupled wi th continuous temperature profiles led to the the conclusion tha t the circulation wi thin these bags is complex and cannot be described by use of a one-dimensional vertical diffusion model. The total inorganic carbon measurements determined from vertical CTD profiles during the 1987 RV Challenger cruise were compared to similar stations sampled during the Transient Tracers in the Ocean Programme (1981). Although the TTO measurements were calculated from a potentiometric titra tion there was no evidence for major errors of accuracy.
12
Nedelec, Florence. "Implementation of a method to determine sub-nanomolar concentrations of iron in seawater and its application to the study of marine iron biogeochemistry at the ocean-shelf interface." Thesis, University of Southampton, 2006. https://eprints.soton.ac.uk/41362/.
Повний текст джерелаАнотація:
The aim of this study was to improve our understanding of the marine iron cycle using a newly implemented technique to measure dissolved iron in seawater. The setting up of a flow-injection analyser with chemiluminescence detection (FIACL) for Fe(II) proved to be non-trivial. Extensive work was undertaken to solve problems relating to our limited level of understanding of the CL reaction, and the variable behaviour of the resins prepared to preconcentrate iron. An analyser for Fe(II)+(III) was optimised, and careful assessment of data demonstrated the high quality of the information interpreted in this study, from the Celtic Sea shelf edge (Northeast Atlantic), and from the North Scotia Ridge (Southern Ocean). The distribution of iron at the Celtic Sea shelf edge was examined, and was used to provide a conceptual framework for future studies. Dissolved Fe (< 0.4 µm) concentrations were measured in samples from nine vertical profiles taken across the continental slope (160 – 2950 m water depth). Dissolved iron concentrations varied between 0.2 and 5.4 nM, and the resulting detailed section showed evidence of a range of processes influencing the iron distributions. The presence of elevated levels of dissolved Fe near the seafloor was consistent with release of Fe from in situ particulate organic matter remineralisation at two upper slope stations, and possibly of pore water release upon resuspension on shelf. Lateral transport of dissolved iron was evident in an intermediate nepheloid layer and its advection along an isopycnal. Surface waters at the shelf break also showed evidence of vertical mixing of deeper iron-rich waters. The data also suggest some degree of stabilisation of relatively high concentrations of iron, presumably through ligand association or as colloids. The possibility of iron limitation of phytoplankton at the shelf edge was not ruled out despite obvious depletion of nitrate. This study supports the view that export of dissolved iron laterally to the ocean’s interior from shelf and coastal zones may have important implications for the global budget of oceanic iron. A set of surface samples collected on a survey between the Falkland Islands and South Georgia were analysed for total dissolvable iron. Results suggested a source of benthic iron near South Georgia. A shift in photo-physiology of phytoplankton towards South Georgia was probably influenced by the transition from iron-limited to iron-replete populations. These results therefore strongly support the hypothesis that South Georgia may be a "pulse-point" of iron to high-nutrient low-chlorophyll waters.
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Fröllje, Henning [Verfasser], Katharina [Akademischer Betreuer] Pahnke, and Thorsten [Akademischer Betreuer] Dittmar. "Rare earth element and neodymium isotope tracing of element input and past ocean circulation: study from North and South Pacific seawater and sediments / Henning Fröllje ; Katharina Pahnke, Thorsten Dittmar." Oldenburg : BIS der Universität Oldenburg, 2016. http://d-nb.info/1116604124/34.
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Kfouri, Claire A. 1980, and Hyo Jin 1978 Kweon. "Seawater as coagulant substitute and the effects on disinfection in chemically enhanced primary wastewater treatment : a case study of Paraty, Brazil and the Deer Island wastewater treatment plant, Boston." Thesis, Massachusetts Institute of Technology, 2003. http://hdl.handle.net/1721.1/29565.
Повний текст джерелаАнотація:
Thesis (M.Eng.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2003.Includes bibliographical references (leaves [133]-[135]).
Paraty is a small touristic city on the South Eastern coast of Brazil plagued with public health problems inherently linked to its poor water and sanitation practices. This thesis centers on the design of an appropriate wastewater treatment facility for the City. The new and interesting use of seawater as a wastewater treatment tool and its effect on the disinfection potential of the treated effluent is also reviewed and tested in a series of jar tests and laboratory experiments Chemically Enhanced Primary Treatment (CEPT) is a wastewater treatment method that serves as an attractive alternative to conventional primary treatment and can also be used as an efficient preliminary step to biological secondary treatment processes. CEPT adopts coagulation and flocculation and accomplishes remarkable increases in the removals of common pollutants and contaminants from the influent. CEPT was chosen as the most favorable treatment alternative for Paraty as it is an expandable, economic and highly efficient system. The main advantage to CEPT is to generate an effluent that can be efficiently and economically disinfected at a low cost compared to secondary treatment. The most optimal dose of FeCl3, polymer and seawater to treat the Paraty sewage were estimated at 40mg/L, 0.1 mg/L and 5% seawater by volume respectively. Jar tests were also conducted at the Boston Deer Island WWTP to check the efficiency of using seawater as a coagulation enhancement mechanism on saline influents. CEPT effluents treated with FeCl3 were also tested for disinfection with both Paracetic acid (PAA) and Chlorine. Although PAA is an effective disinfectant, it was not included due to its high cost. The optimal chlorine dose for Paraty was estimated at 3 mg/L. Additional tests were conducted to test for the disinfectability of the Deer Island effluent treated with CEPT. These tests helped show that the sensitivity of disinfection in the presence of seawater is limited by low seawater concentrations. This thesis concludes with a detailed design of the treatment plant sedimentation tanks, chlorination/dechlorination chambers, and grit removal facility dimensions and draws general encouraging conclusions on the suggested use of seawater as a coagulation catalyst in chemically enhanced primary wastewater treatment.
by Claire A. Kfouri and Hyo Jin Kweon.
M.Eng.
15
Miura, Noriko, Yoshihiro Asahara, and Iwao Kawabe. "Rare earth element and Sr isotopic study of the Middle Permian limestone-dolostone sequence in Kuzuu area, central Japan: Seawater tetrad sffect and Sr isotopic signatures of seamount-type carbonate rocks." Dept. of Earth and Planetary Sciences, Nagoya University, 2004. http://hdl.handle.net/2237/7643.
Повний текст джерела
16
Boissonneau, Patrick. "Propulsion MHD en eau de mer : étude des couplages hydrodynamique-électrochimie-électromagnétisme." Université Joseph Fourier (Grenoble), 1997. http://www.theses.fr/1997GRE10079.
Повний текст джерелаАнотація:
La magnetohydrodynamique (mhd) permet de realiser des propulseurs a reaction fournissant des flux d'eau de mer a grande vitesse sans helice ni piece mecanique en mouvement. En appliquant a un ecoulement d'eau de mer des champs magnetique et electrique, on produit directement au sein de l'ecoulement des forces electromagnetiques (laplace) qui propulsent le navire. Malheureusement l'eau de mer est un electrolyte : le passage des courants amenes par des electrodes entraine une electrolyse non desiree. Le travail presente se consacre a l'etude des couplages suivants : - influence de l'hydrodynamique parietale sur l'electrochimie de l'eau de mer - influence du degagement de micro-bulles sur la couche limite turbulente - determination des courants et des forces au sein de l'ecoulement les parties experimentales reposent sur la confrontation des mesures sur electrodes de platine en cellule d'electrolyse avec des mesures sur electrodes de titane platine en ecoulement reel. Nous avons associe aux mesures traditionnelles electriques et electrochimiques, l'analyse de la production de bulles (electrolyse) et de ses consequences sur l'ecoulement (velocimetrie granulometrie laser doppler & visualisation). Les parties theoriques, touchant l'electrochimie, font une synthese des connaissances et permettent d'identifier les mecanismes dominants et d'expliquer les resultats experimentaux. La partie calcul numerique, concernant le couplage : ecoulement/champs electromagnetiques, repose sur la confrontation de resultats de modeles globaux dedies avec des simulations faites a l'aide de fluent, logiciel commercial (volumes finis 2d).
17
Gao, Yongjun. "Lower Ocean Crust beneath Slow-Spreading Ridges: a Combined Oxygen Isotopic and Elemental in-situ Study on Hole 735B Gabbros." Doctoral thesis, [S.l.] : [s.n.], 2004. http://webdoc.sub.gwdg.de/diss/2004/gao/gao.pdf.
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Auger, Fernand. "Altération des roches sous influence marine, dégradation des pierres en oeuvre, simulation accélérée en laboratoire." Poitiers, 1987. http://www.theses.fr/1987POIT2018.
Повний текст джерелаАнотація:
Etude des facteurs de degradation des batiments et ouvrages anciens en pierre calcaire sous influence marine le long de la facade littorale atlantique francaise, en examinant deux situations : zone de marnage, et milieu aerien. Datation des ouvrages et localisation de la provenance des materiaux (carrieres a ciel ouvert et souterraines). Essais divers sur echantillons provenant des carrieres et d'une digue ancienne soumise au marnage, ainsi que de divers batiments historiques en refection (carottage, essais physiques et mecaniques, technique particuliere de mesure de la vitesse du son dans les carottes). Developpement d'un appareil pour la simulation acceleree de l'alteration aerienne, reproduisant les phenomenes naturels observe sur les monuments et sur les falaises naturelles
19
Huang, Kuan-wei, and 黃冠偉. "Study of Seawater Desalination Using Membrane Distillation." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/38012110035980419959.
Повний текст джерелаАнотація:
碩士嘉南藥理科技大學
環境工程與科學系暨研究所
98
Membrane distillation (MD) is a relatively new separation process which is being investigated worldwide as a low cost, energy saving alternative to other conventional separation processes. Plasma-modified polytetrafluoroethylene (PTFE) membranes for use in membrane distillation were prepared with composite PTFE membranes. The composite membrane consisted of a porous woven support and a dense PTFE layer. The membranes were characterized using contact angle measurement. Finally, the plasma-modified membranes were tested for their performance in the process of desalination by means of the air gap membrane distillation (AGMD) and direct contact membrane distillation (DCMD). It was found that the plasma treatment strongly affected the surface hydrophilicity of the modified membranes and thus enhanced their desalination performance. It was also found that prolonging the plasma treatment time and increasing the plasma power significantly decreased the water contact angle and significantly changed the surface morphology of the modified membranes. Furthermore, the plasma treatment only slightly changed the roughness and surface porosity. Such changes in the surface’s morphology and polarity enhanced the hydrophilicity of the modified membranes and then significantly improved the permeation flux but expectedly decreased the salt rejection.
20
Wu, Chi Chan, and 吳奇展. "Study of Membrane Distillation Process for Seawater Desalination." Thesis, 1998. http://ndltd.ncl.edu.tw/handle/43291422000229101646.
Повний текст джерелаАнотація:
碩士國立成功大學
機械工程學系
86
As the increase of global population compound with the rapid economic growthin mant developing countries, the demand for fresh water in those areas hasresen to a record level. Therefore, seeking a good clean water resource hasbecome an important domestic as well as worldwide issue. It is believed thesea water desalination may be the ultimate way to provide enough fresh water.Among many desalination methods, membrane distillation method is chosen as the interesting method in my study to investigate its performance in separatingthe fresh water from brine water.Membrane distillation is a process in which two solutions at different temperatures are separated by a microporous membrane. Because temperaturedifference which causes a corresponding vapor pressure difference across themembrane provides the driving force of the membrane distillation process. Thevapor evaporates through a porous membrane, and condenses on a coolant surfaceat the other side of the membrane. This paper is focused on air-gap membrane distillation (AGMD). A single stageAGMD facility is set up to investigate the transfer process, and the obtained data is confirmed by the theory of heat and mass transfers. Various kinds ofmembrane are used to examine the relationship between the permeate flux andmany other important parameters such as feed and cooling temperatures,membrane pore size, porosity etc. Finally, the scanning electron microscopy(SEM) is used to observe and analyze the detailed structure of membrane andthe crystallized salt on the membrane surface.The obtained experimental results show that the permeate flux increases exponentially with an increase in hot side temperature and is only slightly affected by the increase in salt concentration, and it*s hardly changed with the coolant flow rate. As the temperature difference between the feed solution and cooling flow increases, the effect due to polarization become obvious. The crystallized salts are found ( under SEM ) to block the membrane pores and result in the reduce of permeate flux or even the damage of membrane structure.
21
Lin, Cheng-Wei, and 林政偉. "Numerical study of wave effect on seawater intrusion." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/72123660115340133807.
Повний текст джерелаАнотація:
碩士國立中山大學
海洋環境及工程學系研究所
94
A two-dimensional finite difference model is developed for the simulation of saltwater intrusion in wave-induced aquifer system with either a confined or phreatic aquifer. The model considers many important factors, such as the dynamic pressure induced by wave motion, the pressure wave equation, the density-dependent Darcy’s Law, and the salt transport equation. This paper presents numerical study of the effect of wave motion, resulting salinity structure responses and phreatic surface fluctuation on the process of seawater intrusion … etc.
22
Kuma, Kenshi. "A Biogeochemical Study on Colloidal Ferric Oxides in Seawater." Doctoral thesis, 1992. http://hdl.handle.net/2115/32721.
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Lin, Ho-Nan, and 林和南. "A Study of Seawater Transparency in the Taiwan Strait." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/86380042080194699325.
Повний текст джерелаАнотація:
碩士國立臺灣海洋大學
海洋環境資訊系
102
The purpose of this study is to understand variations and characteristics of the seawater transparency in the Taiwan Strait and coastal waters around Taiwan by the satellite remotely-sensed data. The data are derived from Moderate Resolution Imaging Spectroradiometer (MODIS) onboard the Aqua satellite. The possible factors that may affect the variations are analyzed. The results show that the seawater transparency near the coastal waters is lower than that in the offshore waters. The lowest seawater transparency is in China coast, followed by the coastal waters of western Taiwan, and then the coastal waters of eastern Taiwan. Seasonal variations of water transparency are also observed. The seawater transparency in most regions is higher in summer and lower in winter. In addition, ocean currents and monsoons may affect the spatial distribution of the seawater transparency. The seawater transparency caused by tides is more significant impact on the coastal area.
24
Magalhães, Raquel Maria Rocha. "Study of the influence of seawater in antibiotic susceptibility." Master's thesis, 2021. https://hdl.handle.net/10216/138043.
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25
Fu, Lan-Chih, and 傅蘭枝. "A Study of Seawater Transparency at Bisha Fishing Harbor." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/19412167827171721710.
Повний текст джерелаАнотація:
碩士國立臺灣海洋大學
海洋環境資訊學系
99
Abstract The purpose of this study is to understand the variation of seawater transparency at Bisha Fishing Harbor in Keelung, Taiwan by using Secchi disk, and then analyze the possible factors that may influence its variation. After measuring every week for a year, the result shows that the average seawater transparency at Bisha Fishing Harbor is low to 4.8 ±1.3 meters in summer, and it’s because that plankton would perform photosynthesis under the sunshine; in contrast, the transparency in winter is high to 7.6 ±2.0 meters. From the continuous measurements for 30 days, the result shows that there is a variation period of 4~5 days by using Fast Fourier Transformation. According to the analysis of correlation, it indicates that the transparency is somehow related to the wind speed variation, but not correlated with tides. We can find that during typhoon and strong northeast monsoon periods, the transparency reduces dramatically because of the sediments disturbed by stormy waves. During the measuring period, we also found a lot of artificial interference, for example, the floating garbage and greasiness on the sea, human activities around the port, construction progressed in embankments and so on. These factors may influence the seawater transparency indirectly, and lower the visibility of the sea. Keywords: Secchi disk, Transparency, Bisha Fishing Harbor
26
Kailasam, M. "Effect of thermal effluent on water quality in relation to benthic community." Thesis, 1995. http://eprints.cmfri.org.in/6989/1/TH-63_Kai.pdf.
Повний текст джерелаАнотація:
The advancement of industrialization and urbanization along the
coastal region has received considerable attention of environmental scientists
in the recent past. Owing to an increasing trend in the above factors, large
volume of untreated industrial, agricultural, domestic and other wastes are
frequently discharged into the sea. This indiscriminate discharge of the waste
materials may endanger the safety of the aquatic life and even may cause
irrepairable damage to the otherwise very delicately balanced marine
ecosystem. Besides, some industrial waste water may contain high
concentration of toxicants at lethal or near lethal level. If such untreated waste
water is discharged into the sea, the toxicants may be picked up by fishes and
shell fishes and these get concentrated in the tissues until the organisms are
no longer fit for human consumption (Hammond, 1971).
The ever increasing demand of electricity for industrial and domestic
purposes has urged the Government, Public and Private sectors to install more
and more electricity generating stations. The location of any industry is
selected based on both the availability of reasonably good water for the
industrial processes and the facility for discharging the wastes. The thermal
power plants are always installed near to larger water bodies such as
reservoir,lakes and sea and these plants use an enormous amount of water as
transfer medium to remove the heat from the condensers and dissipate it into
the nearest aquatic environment. The pumping rate of cooling water varies
widely according to the design of the plant. Pannel et al (1962) have pointed
out that dispersion of heat will be by mixing with water and not by cooling to
the atmosphere. As a result of this, the effects of heated effluent are felt at a
greater distance from the out fall than if the heated water was spread out and
cooled at the surface (Raymont and Carrie, 1964; Ansell, 1963b)
27
Tseng, Chao-Hung, and 曾兆弘. "Study on Ocean Thermal Energy Conversion with Seawater Flow Control." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/p9rvms.
Повний текст джерелаАнотація:
碩士國立臺灣海洋大學
電機工程學系
104
This thesis studies on dynamic analysis of Ocean Thermal Energy Conversion, including open-cycle and closed-cycle OTEC system which both have flow rate control model. The study analyzes dynamic characteristic and variation in seawater flow rate when system operate on islanding and grid-connect. From the study results, it is shown that closed-cycle OTEC can generate same power with less seawater flow rate than open-cycle OTEC. Seawater flow can’t change so rapidly that it results in a disturbance on the generator output. When micro-grid is connected to the electricity, voltage and frequency can be returned to normal steady state.
28
Huang, Li-Li, and 黃麗莉. "Study of The Analytical Method for Chromium(VI) in Seawater." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/68736012850339495801.
Повний текст джерелаАнотація:
碩士國立中山大學
海洋生物科技暨資源學系研究所
94
In this research, in order to set up the ultimate approaches to determine the content of chromium(Ⅵ) in seawater, different pH values, the amount of chelating agent, chelating time and extraction time were investigated in two different solvent extraction systems, APDC-MIBK and Aliquat 336-MIBK. In APDC-MIBK system, the ultimate extracting condition is that 400 mL sample is adjusted to pH 3.0, added 4 % APDC 4 mL to chelate chromium(Ⅵ) for 60 minutes, and added 20 mL MIBK to partiton into two fractions for 5 minutes. The recovery in APDC-MIBK system is 68 %~ 123 %. The method detection limit is 0.2 ppb. In Aliquat 336-MIBK system, the ultimate extracting condition is that 400 mL sample is adjusted to pH 2.0, added 5 % Aliquat 336 4 mL to chelate chromium(Ⅵ), added 20 mL MIBK to be shaken for 2 minutes, and partitoned into two fractions for 5 minutes. The recovery in Aliquat 336-MIBK system is 80 %~ 120 %. The method detection limit is 0.1ppb. Although in APDC-MIBK system assorted metals can be extracted at same time, it is steadier in Aliquat 336-MIBK system than APDC-MIBK system. Therefore, it is a feasible extraction method to adopt Aliquat 336-MIBK system to determine the content of chromium(Ⅵ) in seawater.
29
Gil, Daniel Ribeiro. "Seawater desalination using wind energy. Case study: Johnny Cay-Colômbia." Master's thesis, 2016. http://hdl.handle.net/10451/26070.
Повний текст джерелаАнотація:
Tese de mestrado integrado em Engenharia da Energia e do Ambiente, apresentada à Universidade de Lisboa, através da Faculdade de Ciências, 2016A escassez de água potável é um problema atual em certas regiões do planeta e vários estudos indicam que todos os dias se está a alastrar a outras regiões do globo. Na literatura há uma enorme quantidade de indicadores e de índices relacionados com a água. Cada um deles tem sido definido sob diferentes premissas e condições, por isso, a sua aplicabilidade pode ou não ser adequada em todas as áreas de estudo. Um dos indicadores mais utilizados é o “índice de stress hídrico” que afirma que quando as reservas anuais de água estão abaixo dos 1 000 m3 por pessoa, a população enfrenta escassez de água. No entanto a água é um recurso muito complexo. Ao contrário do que acontece com um recurso estático, como terra, a água ocorre num ciclo muito dinâmico de chuva, escoamento e evaporação, com enormes variações temporais e espaciais, bem como variações na qualidade. A água pode ser um incómodo (em cheias), bem como um recurso de salvação (em secas) sendo que ambas as condições podem ocorrer num local dentro de um único ano. Por esta razão, a disponibilidade anual de água num determinado local tem pouco significado quando estamos a avaliar a sua escassez. Existem três fatores que são a principal causa da falta de água no globo: a variabilidade climática; o rácio supply/demand e os acessos. O primeiro destes fatores é um fenómeno natural causado principalmente pela variação da quantidade de precipitação. No entanto, há estudos que indicam que, devido às alterações climáticas, há cada vez fenómenos mais extremos de precipitação, causando cheias e/ou secas mais ou menos intensas e prolongadas. O segundo fator tem diversas origens, entres elas, o desenvolvimento económico de uma região, que potencia o uso de água nas indústrias e noutros setores, por outro lado a sobrepopulação, a poluição, o aumento da qualidade de vida e o ineficiente uso do recurso disponível. O terceiro fator é o principal no que toca aos números de pessoas afetadas (663 milhões), neste caso o recurso existe mas por razões económicas não está disponível. Para travar este problema sugeriram-se algumas soluções, entre elas a dessalinização da água do mar. Atualmente há mais do que 17 000 centrais de dessalinização no mundo que, combinadas, produzem um total de 80 milhões m3 de água potável em mais de 150 países, abastecendo mais de 300 milhões de pessoas. Todas estas centrais funcionam com base em dois principais processos de dessalinização: os processos térmicos (ou de mudança de fase), que usam um método equivalente ao ciclo da água,ou seja, a água salgada aquece, evapora, condensa e precipita sob a forma de água potável e os processos de membranas, onde, como o nome indica, o processo de separação dos sais minerais da água é feito com recurso a uma membrana. Dentro das tecnologias com base em processos de membranas destacam-se os sistemas de osmose inversa (reverse osmosis em inglês, ou RO) que representam 65% da capacidade total instalada em dessalinização. Nesta tecnologia a água do mar é bombeada (com recurso a uma bomba de alta pressão) contra uma membrana semipermeável, na qual ficam retidos a maioria dos sais contidos na água, produzindo assim água potável. O custo dos sistemas RO decresceu bastante desde a sua comercialização em 1970 até hoje, devido a melhorias das tecnologias das membranas, bombagem e sistemas de recuperação de energia. No entanto, os seus custos continuam a ser bastantes elevados, principalmente devido à grande quantidade de energia necessária para abastecer a bomba de alta pressão. Energia essa que vem com impactos ambientais associados, mais especificamente a emissão de gazes de efeito de estufa, devido aos combustíveis fósseis utilizados pelos sistemas convencionais na produção de eletricidade. Este facto motivou o desenvolvimento de tecnologias de dessalinização integradas com fontes de energia limpa e grátis, as energias renováveis. Em ilhas e regiões remotas, onde as instalações elétricas são economicamente inviáveis e o recurso eólico é abundante, a dessalinização da água do mar através da energia disponível no vento surge como uma possível solução à escassez de água potável. O presente trabalho tem como objetivo o estudo da viabilidade técnico-económica de um microssistema de dessalinização da água do mar por osmose inversa, utilizando energia eólica e tendo como caso de aplicação na ilha Johnny Cay, que não possui água potável nem eletricidade. Johnny Cay é uma pequena ilha Colombiana localizada no mar das Caraíbas. Esta é principalmente visitada por turistas que aproveitam o sol e as águas cristalinas para beber uma bebida fresca ou comer peixe acabado de pescar num dos diversos restaurantes e bares espalhados pela ilha. No entanto, como não existe água potável nem gelo estes bens têm de ser importados para fazer face a uma demanda média anual de 120 450 L e 369 380 kg, respetivamente. Isto dificulta as contas dos comerciantes ao mesmo tempo que traz prejuízos ambientais devido ao combustível gasto para transportar os bens, e à grande quantidade de plástico necessário. Tendo em conta as necessidades previstas da ilha, bem como o recurso de energia renovável disponível, é proposta a implementação de um microssistema híbrido composto por uma turbina eólica ligada a um sistema de dessalinização da água do mar por osmose inversa (seawater reverse osmosis em inglês, ou SWRO) e a um gerador de reserva, de maneira a produzir água potável e fornecer eletricidade para a comunidade local. Um sistema de energia solar fotovoltaica será também utilizado para suportar as necessidades elétricas. Em ilhas pequenas, onde a mão-de-obra qualificada é escassa e o orçamento é limitado, o custo de investimento juntamente com a simplicidade pode ser um fator preponderante na escolha de um sistema de dessalinização. Tendo isto em conta, como grande parte da energia necessária numa unidade SWRO é consumida pela bomba de alta pressão (high pressure pump em inglês, ou HPP), a ideia de uma ligação mecânica entre a turbina e a HPP parece à primeira vista mais simples e económica do que a utilização de um aerogerador, visto que deste modo vão existir menos formas de conversão de energia envolvidas (com o uso de um aerogerador normal seria necessária a conversão de energia mecânica em elétrica que teria de ser novamente convertida em energia mecânica antes de chegar ao RO). No sistema estudado a energia disponível do vento é transferida para as pás do rotor que está acoplado a uma bomba de cilindrada fixa, esta, por sua vez, está ligada a um sistema hidráulico que ocupa toda a extensão interior da torre da turbina, desde a altura da nacelle até ao solo. A velocidade de rotação do rotor é proporcional ao fluxo bombeado pela bomba. Através de um conjunto de válvulas no sistema hidráulico o fluxo do óleo que chega ao RO e ao gerador é mantido praticamente constante enquanto o excesso é desviado de volta para o cimo da torre. A energia contida no óleo é então transferida à água salgada através de um motor acoplado à bomba de alta pressão do RO fazendo movimentar 1,43 m3/h de água salgada através de dois módulos de membranas do tipo spiral-wound. Deste fluxo 0,5 m3/h sai sob forma de água potável.
Water scarcity is a current problem in certain parts of the world and several studies indicate that every day it is spreading to other regions of the globe, mainly due to population growth, the desire to improve life’s quality and climate changes. To minimize this growing problem seawater desalination techniques have been applied. However, conventional systems are very expensive and require a lot of energy, usually from fossil fuels. On islands and remote areas, where electrical installations are economically unviable and the wind resource is abundant, desalination of seawater using the kinetic energy of wind comes up as a possible solution to the shortage of drinking water. This work aims to study the technical and economic feasibility of a seawater desalination microsystem by reverse osmosis, using wind power and with a practical application in the small Colombian island, Johnny Cay, which has no drinking water nor electricity.
30
Chen, Tsung-Ching, and 陳宗慶. "The Study of Solar Assisted Membrane Distillation on Seawater Desalination." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/94219624821950798768.
Повний текст джерелаАнотація:
博士淡江大學
化學工程與材料工程學系博士班
98
The solar heat assisted membrane seawater desalination system is technically and economically feasible, which is constructed of solar collectors and membrane distillation device for energy saving water purification. The diving force of separation in membrane distillation device is supplied by infinite resources of solar radiation. Solar desalination systems are classified into two categories, i.e. direct and indirect collector systems. There are some advantages for the direct indirect solar heat driven systems (1) the direct solar heat system integrates the solar absorber as an additional heat supply source and membrane distillation process into a small-scale unit which uses the solar radiation as the heat source to produce high purity water; (2) the hot brine is indirectly preheated by the solar heating system to prevent equipment fouling and the maintenance costs of solar collectors and hot water storages are low, respectively. The purposes of this study are (1) to study new design of ultra-thin channel solar water heater, direct contact membrane distillation, dual films membrane distillation, immediate solar assisted membrane distillation systems with mathematical modeling and experimental studies; (2) to develop a two-dimensional mathematical model and propose a general numerical method for solving this complex mathematical model in predicting pure water productivity of membrane distillation systems; (3) to study the collector efficiency improvement of solar collector and the effect of temperature distributions, temperature polarization and pure water productivity improvement on the membrane distillation systems. The results show that the agreement between the experimental results and theoretical prediction are fairly good.
31
Yang, Tai-I., and 楊岱宜. "Study on the Interference in the Determination of Ammonia in Seawater." Thesis, 2001. http://ndltd.ncl.edu.tw/handle/10761910716004628024.
Повний текст джерелаАнотація:
碩士國立臺灣大學
海洋研究所
89
This study focuses on the pH and buffering capacity problems involved in the determination of ammonia in seawater by the indophenol blue colo-rimetric method. The pH-shift puzzle was unraveled by acid-base titration. The major buffering capacity for the indophenol blue method is induced by the combination of the phenate system (pK = 10) and a previous — un-known Mg-citrate system. By adding extra alkali reagent to compensate for the pH difference in saline media, the molar absorptivity was found to be 21000 /M/cm at 640 nm. For sample with a variety of salinities, an empirical equation is suggested to correct the results.
32
邱士恩, Shin-En Chiu, and 邱士恩. "A study on performance of PVDF composite membrane in seawater desalination." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/46664835469527629702.
Повний текст джерелаАнотація:
碩士淡江大學
化學工程與材料工程學系碩士班
103
In this study, the flat-sheet composite membranes of polyvinylidene fluoride (PVDF) supported on hydrophilic cellulose were prepared, and their performances in direct contact membrane distillation (DCMD) for seawater desalination were also investigated. The simulated seawater of 3.5 wt% NaCl solution was adepted as the feed. The dope solution consisted of PVDF, Triethyl phosphate(TEP) and Tween-20, and four conditions, 10、20、40 and 60 wt% triethylphosphate (TEP) solution were applied in the coagulation bath. From the observation by SEM, the surface pore sizeof membrane increased with the increasing of TEP concentration in the coagulation bath. The experimental results of DCMD showed that the membrane prepared from higher TEP concentration had a larger permeate flux because of its larger pore size on the surface. And increasing the feed temperature of the feed can significantly increase the flux, but the polarization phenomena become more serious, but the effect of increasing feed flow rate the effect is not obvious on the flux.
33
Chen, Shao-Yu, and 陳劭宇. "Study and design of seawater Powering module and Optimized output power." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/4z6e9s.
Повний текст джерела
34
Chen, Hsiao Ling, and 陳筱玲. "Study on carbon nanotubes/PEDOT:PSS composite as cathode material for seawater batteries." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/84c7ha.
Повний текст джерела
35
Wang, Cheng-Yun, and 王程筠. "Study on the formation reaction of the silico-molybdenum complex in seawater." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/8r9akk.
Повний текст джерелаАнотація:
碩士國立臺灣大學
海洋研究所
105
Dissolved reactive silicate in natural water is usually determined colorimetrically based on the formation of a yellowish silicomolybdenum complex. The product and reaction rate can be affected significantly by the amounts of reagents added, and the optimal conditions are optimized by observing the color formation kinetics. Several criteria have been found: the final Mo concentration requires at least 30 mM, the final pH needs to be adjusted to 1.5, and the H+/Mo ratio should be around 2.5. To keep the above condition one needs to prepare a high Mo concentration reagent at [Mo]675 mF. A prior mixing with ammonia at a concentration covering more than half of Mo concentration allows the reagent stable at room temperature. In real measurement the sample is added with this reagent and acid to give a final [Mo] of ca. 30 mF. The reaction can reach >99% within 120 s at 25 ℃,. The molar extinction coefficient of silicomolybdum complex is 2175 M-1cm-1. The salinity interference is around 2%. The interference by phosphate is equivalent ot half of silicate concentration (molar extinction coefficient =1170 M-1cm-1 ). The reaction time in manual operation requires 3 min, which can be readily converted to autoanalysis. However, to improve the precision of measurement, a stepwise concept has been adopted in this study. The sample mixed with reagents is allowed to fill into a flow cuvette and the liquid is trapped in a spectrophotometer. The measurement was made 180 s after sample loading. At 250 μM the relative standard deviation reaches 0.2%, the detection limit is 0.5 μM using 1 cm cuvette, and can be further lowered to 0.1 μM if a 5 cm cuvette is used. The analysis throughput is 20 samples per hour.
36
Chen, Chun-Nan, and 陳俊男. "The study of double-effect direct contact membrane distillation on seawater desalination." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/10080288624855392554.
Повний текст джерелаАнотація:
碩士淡江大學
化學工程與材料工程學系碩士班
100
The direct contact membrane distillation(DCMD) device is a simple design of MD systems in which both the cold stream and hot stream are kept in direct contact with the membrane. The advantages of DCMD lie in its simple configuration, the need for only small temperature differences and nearly 100% salt rejection. In this study, the DCMC process are performed at middle temperature operation (about 40 °C to 70 °C) of hot inlet stream associated with a constant cold stream inlet temperature(about 25 °C). A concurrent flat-plate device was constructed and carried out to verify the theoretical prediction of pure water productivity on saline water desalination. The purposes of this study are (1) to develop a new semi-empirical expression of the membrane coefficient from the results of the pure water production of the experiment and the mathematical modeling; (2) to study a new design of double-effect direct contact membrane distillation system and develop a two-dimensional mathematical model and propose a general numerical method for solving this complex mathematical model in predicting pure water productivity in membrane distillation systems. The numerical results from the mathematical modeling of the resultant partial differential equations were obtained using the finite difference technique of the fourth-order Runge-Kutta method. The influences of the inlet saline water temperature and volumetric flow rate on the pure water productivity as well as the hydraulic dissipated energy are also delineated.
37
Yuwen, Pai, and 白育文. "The Energy-Saving Study Of The Main Cooling Seawater Pump For Ships." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/86157522722639961307.
Повний текст джерелаАнотація:
碩士國立高雄海洋科技大學
輪機工程研究所
100
This main goal of this study is to control the flowrate of the cold fluid while it flows through main water cooler or to fix the cold fluid temperature while reducing its flux, especially under the different weather conditions or the temperature change of ambient water. In other words, in order to save the consumption of electric power and achieve energy conservation, the same heating effect can be achieved by controlling the motor rotation. Employing smooth, four-fin, six-fin, and eight-fin tubes, a heat exchanger with counterflow arrangement is made for the hot water and cold water which serve as the inner and outer working fluids in the test. In addition, with a well-stirred design, the hot water is kept around 70 ℃ in the hot bathing constant-temperature reservoir whereas the cold water temperature is set at 20 ℃. The temperature and pressure differences are recorded as the working fluids are pumped through the test unit. For a fully developed flow, the tested Reynolds number ranges from 200 to 3000. It is shown that the heat transfer characteristics and friction factor of the exchanger with fins are larger than those with smooth tube. The more the fins are used, the better the heat transfer performance will be. It is understood that there is always a great demand on cooling water system for ships. Through this work, it is expected that the efficiency of ship operation can be enhanced and the maximum outcome for ship owners can be obtained.
38
Shih, Jyun-Han, and 施鈞瀚. "A study of composite nanofiber membrane applied in seawater desalination by membrane distillation." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/3k9a2a.
Повний текст джерелаАнотація:
碩士國立臺灣科技大學
材料科學與工程系
99
The current research and application of electrospinning process on the textile engineering, biomedical engineering, tissue engineering, environment engineering. For the past few years, some research teams have been use the electrospun membrane for the liquid filtration application. In this study, two composite nanofibrous membranes of PVDF and PVDF-HFP prepared by electrospinning process were employed in a direct contact membrane distillation (DCMD) system. The nanofiber membrane combined the high tenacity spunbond nonwoven. And this membrane was electrospun nanofiber nonwoven membrane and spunbond combined to form a sandwich structure of the folder into a SES (Spunbon-Electrospun-Sponbond) composite nanofiber membrane. It reach high porosity, low pore sizes, nanofiber grade, high specific surface area, and high hydrophobic composite membrane for the direct contact membrane distillation system. By SEM observations, porosity analyzer technique and contact angle measurement, it indicated that the nanofibrous membrane of the average fiber diameter of 170nm and maximum pore diameters distribution of 0.3μm is the best membrane applied in DCMD system. During 12 hours, experiment with the following conditions: Bulk temperature difference of 55°C , and both the two side flow rate of 210 mL/min, it resulted in that the permeate flux of PVDF-HFP composite membrane is higher 4.28kg/m2hr than PTFE commercial membrane. From this 12 hours experiment, the salt rejection of PVDF-HFP (99.9901%) was better than that of PVDF composite membrane (99.9888%) and was the same as that of PTFE commercial membrane (99.9951%). Consequently, the PVDF-HFP composite nanofibrous membrane is significantly increase the permeation flux and salt rejection than the PVDF composite nanofibrous membrane in the DCMD system.
39
Huang, Chun-Ying, and 黃俊穎. "Study of Seawater Intrusion Mechanisms in a Coastal Area in Yunlin and Chayi." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/60439208011625732400.
Повний текст джерелаАнотація:
碩士國立中正大學
地震研究所暨應用地球物理研究所
97
Long-term overpumping groundwater in the coastal area of Yunlin and Chiayi has caused a depression cone with water level in 20 m below sea level since 1982. The depression cone goes on expanding indefinitely and water level keeps dropping due to continuous overpumping. Consequently, it may cause serious seawater intrusion. In this study, a precise numerical simulation is conducted to evaluate all possible mechanisms of seawater intrusion in Yunlin and Chiayi areas. Based on the detailed stratigraphic information, the surface aquifer is pinched out toward seaside and the deep aquifers are exposed to seawater at the surface tens kilometers away from the coastal line. These demonstrate that seawater intrusion is less possible to happen. However, serious seawater signal has been detected in deep aquifers in the studied area. In general, there are four possible sources of seawater: (1) Seawater intrudes into aquifer through high conductive layers due to groundwater depression cone. (2) Seawater infiltrates from the land surface during high tide. (3) Brackish connate water. (4) Seawater infiltrates from surface through mass pumping wells. This study concentrates on evaluate the first two mechanisms. The 3 dimensional conceptual model is accordingly constructed and is simulated by FEMWATER. The results demonstrate that seawater is difficult to intrude into inland deep aquifers. In addition, the seawater signals are exclusively observed around the area of groundwater depression cone; therefore, the seawater signal in deep aquifers is not caused by connate brackish water. The most possible mechanism is that the seawater infiltrates into deep aquifers through the deep pumping wells which penetrate major aquitards.
40
Chien, Yi-Fang, and 簡怡芳. "Study of the Masking Reagents Used in the Determination of Silicate in Seawater." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/47612140665843901475.
Повний текст джерелаАнотація:
碩士國立臺灣大學
海洋研究所
96
Abstract Silicate in natural water is usually determined colorimetrically by reacting with molybdate reagent. A further treatment using masking agent is necessary to eliminate the interference of phosphate. This study focuses on the mechanism of the masking reagents. Four reagents were chosen namely oxalic acid, tartaric acid, citric acid and EDTA, and their effects to the silicate determination were monitored by a thermostatic closed circulating device. It was found that different reagents could cause fading of silicomolybdic complex, and that citric acid provides the least fading rate and minimum required dose. In manual operation freshwater samples should be measured with in 40 s and 5.5 min after mixing with citric acid reagent, whereas for seawater sample the optimal measuring time is between 30 s and 2.5 min at room temperature. For flow injection analysis when a heating bath at 40 ℃ is applied the yellow color stream should be lead to a detecting device, within 15 s after meeting the reagent flow, for prompt measurement.
41
Chen, Jung-Wei, and 陳忠偉. "Study of suitable water table and seawater intrusion in Chou-Shui alluvial fan." Thesis, 2002. http://ndltd.ncl.edu.tw/handle/25051692349677738245.
Повний текст джерелаАнотація:
碩士國立成功大學
資源工程學系碩博士班
90
ABSTRACT The hydro-geological structure model in Chou-Shui alluvial fan is established to investigate the issues for safety yield and seawater intrusion for water quality from 1995 to 2000 year. The MODFLOW computer code was applied to simulate the 3-D groundwater flow pattern and to validate in situ hydraulic parameters for Chou-Shui alluvial fan. The safe yield is computed by Hill method. A certain processes also estimate the safe yield related to the suitable water table. Furthermore, the MT3D computer code transport model with considering the suitable water table is applied to evaluate the seawater intrusion in the Chou-Shui alluvial fan. Simulation results indicate that as the discharge of Chou-Shui alluvial fan is reduced from 2080 × 106 tons per year to 1250 × 106 tons per year, both the measured water table and the predicted water table are closed. The averaged safe yield of Chou-Shui alluvial fan was 1,229 × 106 tons per year from 1995 to 2000 years. The results also show that the suitable water table is lower than the observed water table at the top fan whose area can be pumped groundwater amount. On the other hand, the suitable water table is higher than the observed water table at the last fan whose area needs to recharge/replenish the groundwater amount. The contamination areas of Chou-Shui alluvial fan defined by using the index of the TDS is agreed with those defined by using the index of the ratio of CL/HCO3 . The variation of the concentration wasn’t substantially changed between 1999 and 2000 years. As considering the suitable water table to simulate the concentration of TDS and the ratio of CL/HCO3 after 5 and 10 years, results show that they are significantly reduced at the top and middle fan while slightly reduced the last fan.
42
linsasu and 林聖書. "Study on Pressure Decompression Type Seawater Desalination System Driven by Solar Focusing Heating." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/07096538669865827334.
Повний текст джерелаАнотація:
碩士樹德科技大學
應用設計研究所
95
In this article, the research is primarily focused on the solar energy seawater desalination system. Seawater is characterized by low boiling temperature when it is under a pressure lower than one atmospheric pressure. By using solar energy as a heat source for heating and extracting air from the seawater desalination system manually so as to reduce pressure in the system, it is possible to boil and evaporate seawater with lower heat energy. The solar radiation can help boil and evaporate seawater once it is heated through the heat-collecting effect of the solar collector, and then the motor will circulate the seawater to make the cooled and evaporated vapor condense into potable pure water. The said system is expected to solve the crisis of lacking fresh water in the future, reduce the harm to the earth due to consumption of energy, slow down the green house effect and further reach the goal of sustainable development. Combining the seawater desalination with the application of solar energy is able to reduce the utilization and consumption of heat energy in the process of seawater desalination. In the course of producing fresh water, the researcher applied the principle of parabolic focusing to calculate the optimal concentration ratio with reference to relevant literature, to produce the heat collecting and evaporation equipment, and to modify the cylinder into manual vacuum air-extracting equipment, closed vacuum chamber, etc. The experimental results showed that the temperature of seawater of 350 ml raised from 26.2℃ to 86.4℃ within 15 minutes in the initial stage. The heat-collecting efficiency of the heat-collecting device was as high as 55.3%. Within 15 minutes., the circulation cooling water could reduce the water temperature of water of 7500 ml reduce from 42.1℃ to 25.4℃ and produced heat of 125.25 kcal. If the system structure was enhanced, the air-extracting equipment could reduce the system pressure to 25 cm-Hg under an optimal condition. This would be in line with the heating temperature of the solar heating system and could produce a sudden boiling phenomenon of seawater, meeting the economic effect. The best fresh water production capacity of the system is to produce 38ml of fresh water with salinity of 220 ppm from 200ml of seawater within 30 minutes. The fresh water so produced will also meet the national potable water standard. This system can be used to produce fresh water for fishing vessels and provide domestic water to offshore islands. Producing fresh water by utilizing solar energy and supplying domestic water to fishing vessels and offshore islands will not need to consume extra energy. Moreover, the manual pressure reducing equipment will allow the water so desalinated to meet the national potable water standard. To sum up, the system will be one of the methods to solve the problem of water deficiency on the sea and offshore islands.
43
Ye, Jia-Wei, and 葉家維. "The Study of Numerical Simulation of Brine Dispersion for Taoyuan Seawater Desalination Plant." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/57707616520327445087.
Повний текст джерелаАнотація:
碩士國立臺灣海洋大學
河海工程學系
100
Since industrial development and the population expanded massively in Taoyuan, the water demand increased rapidly. Thus, the government plans to build the seawater desalination plant which can supply the demand of water. This study simulated the emission of 90,000 tons brine every day to the offshore of Taoyuan seawater desalination plant for a month. This paper utilized the salinity(psu) as an index and discussed the condition of brine dispersion for the three configurations. Moreover, we assess the feasibility of the discharging work. In this study, we used numerical models(Mike 21andMike 3) which developed by DHI. These numerical models simulated the work by using Hydrodynamic module(HD) and Advection-dispersion module(AD) with nest-shape method. Besides, we set three different computational domains. By using harmonic analysis, we can obtain the water level as the boundary conditions of the HD module on the largest computational domain(M1). For a more accurate simulation, we extracted water level boundary condition from the largest computational domain(M1) to simulate the middle computational domain(M2).The same as previous step, we also extracted water level boundary condition from the middle computational domain(M2),to calculate the smallest computational domain(M3), and added an AD module to the smallest computational domain(M3) to understand the effect on the salinity concentration after the dispersion of high-concentration brine. According to the simulation results, we can observe the salinity of sea water after brine discharging. Except the surrounding area approximate 2000~5000m2 of the layer of discharging point, the salinity is higher than the background value of about 1~3psu. On the other hand, the remaining salinity of waters, just higher than the background value of 0.01~0.5psu which is no cumulative effect. It is obvious that after the dual effect of dispersion and advection, the high concentration of brine can quickly mix with the surrounding seawater and reduce the impact of discharge water on the marine environment.
44
Chang, Chi-Kai, and 張祉凱. "A Study on the Integrated Numerical Model of Groundwater Resources and Seawater Intrusion." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/rybjj7.
Повний текст джерелаАнотація:
碩士國立臺灣大學
生物環境系統工程學研究所
105
Pingtung Plain is an important area for the usage of groundwater resources, with irrigation and household as the main usage in the past. In recent years, the development of fishing industry starts to flourish, which causes a competitive utilization of groundwater resources in Taiwan’s coastal areas, resulting in groundwater overdraft and an increase demand in the needs of water, which leads to various problems such as land subsidence, seawater intrusion and salinization. In order to explore the situation of seawater intrusion in Pingtung Plain, this research applies Soil Water Assessment Tool (SWAT), MODFLOW groundwater model and MT3D to stimulate the numerical model of integrated groundwater, seawater intrusion and the development of water resources in Pingtung Plain. This study applies the external factors of Pingtung Plain provided by Water Resources Agency, to stimulate the change of chloride concentration in groundwater due to the increasing pumpage phenomenon causes by future economic growth and rise in sea level as climate changes. The study is divided into two simulation conditions: i.To stimulate in 2020 to 2039, the rise in sea level in 3 different cases: 27cm, 40cm and 54cm. The stimulated result has shown that, under the current pumping situation, the rise in sea level in the mentioned cases has no significant effect towards the inland chloride concentration. However, the high concentration of chloride in coastal area moves towards inland. ii.Based on the future economic development, predict groundwater pumpage will respectively increase by 10%, 20% and 30% over the existing percentage. Result has shown that, the chloride concentration in the first aquifer has a significant growth as pumpage increases. However, the second and third aquifer has no significant changes as pumpage increases. The numerical model of integrated groundwater, seawater intrusion and water resources development set up in this research investigates the spatiotemporal changes of chloride concentration as climate changes and water demand increases. This model can examine the affects towards the quality of water resources as the increase usage in water amount due to future economic development, and act as a reference for the government in decision making and implementation.
45
Chang, Chun-cheng, and 張峻誠. "A Study of Water Quality Improvement in Seawater Aquaculture Using A Biofilter System." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/b7bhmk.
Повний текст джерелаАнотація:
碩士國立中山大學
海洋環境及工程學系研究所
106
The study mainly concentrates on dealing with fish farming wastewater through biofilter system and discusses the transformation when nutrients pass the biofilter system. Meanwhile, the interaction was analyzed and the variation of factors were observed during experiments. The study discovers the time interval of hydraulic retension time influences biofilter system result a lot. Hence, the tests was designed based on the time interval of hydraulic retension time and observe general results for finding which meets operation setting of the practical demand. Furthermore, the results are collected and summarized to calculate the scales and costs of biofilter system when used in practical application, and also be the references of research and practical use afterwards. In the study it discovers the total of nitrogen keep raising if the feed is put into water,and also discovers it will exists as organic substance, which means algae, after degradation and absorption. The experiment results show the proportion of organic nitrogen to inorganic nitrogen is four to one. The biofilter system designed in the study discovers denitration still happens under high-dissolving oxygen condition and determines the elimination of nitrate effectively. After calculation implemented in this study, 35.5 % of the total nitrogen amount were removed from the water system if the time interval was under 8 hours. Without changing the water, biofilter system can treat 20 % of the general water volume per day, and it’s volume covers 5 % of total water amount.
46
Jung-YenHsu and 徐蓉彥. "Study on effects of land subsidence on seawater intrusion in the Pingtung coastal area." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/71039906258308278773.
Повний текст джерелаАнотація:
碩士國立成功大學
海洋科技與事務研究所
104
Coastal and inland aquaculture fisheries flourish in the Pingtung Plain result in groundwater salinization pollution in coastal areas. In the previous studies, the use of groundwater numerical model of groundwater salinization was the most common way, while the researchers did not consider the impact of land subsidence, these models would not be able to accurately predict long-term groundwater salinization, and meanwhile, these models would not be able to accurately assess the effect of various remediation methods, too. MODFLOW groundwater model is used in this study with its sub-modes MT3D to simulate Pingtung coastal area groundwater condition, and consider the change of hydrogeological properties after land subsidence additionally. To quantize the change of hydrogeological properties, the theory of poroelasticity will be used. Via the process of calibration and verification, and different scenarios to predict the salinization, the model which considered the consolidation and the one did not would be analyze. The remediation strategy can reduce the area of salinization effectively. The model did not considered the consolidation improves the area of salinization is relatively significant due to the value of hydraulic conductivity stay fixed, and there won’t have great change in flow conditions. Meanwhile, the hydraulic conductivity of the model considered the consolidation is gradually become smaller, it means the flow conditions not be so well, and the effect of the remediation is reduced. The results show that there are great differences between the model considered the consolidation and the one did not. In the prediction of salinization, taking no account of consolidation might underestimate the extent of salinization, therefore, taking into account the impact of land subsidence is essential.
47
Hwang, Kuan-Luen, and 黃冠綸. "Interference Study of the Colorimetric Method for the Determination of Dissolved Oxygen in Seawater." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/93641270020129813057.
Повний текст джерелаАнотація:
碩士國立臺灣大學
海洋研究所
94
Four potential interference factors involved in colorimetric determination of dissolved oxygen were studied. Those factors include the concentrations of oxygen and iodide in the sample and reagent, the wavelength and temperature at which the detection is made. Evaluations were made both theoretically and experimentally on the linearity of the calibration curve. The results show that concentrations of dissolved oxygen and iodide cause variation of the ratio between molecular iodine and tri-iodide, thus leading to a bending phenomenon of the calibration curve. Detection made at near the isobestic point (466~469 nm) may reduce the above interference at the cost of losing up to 30% of the sensitivity. The colorimetry can be carried out at 456 nm but it is important to ensure a high strength of iodide reagent (e.g. the final strength = 33 mM) so as to minimize the bending effect. The temperature of the sample is found essential because it alters the spectrum of the final color and causing a shift of the isobestic point (ca. 0.5 nm per 5 oC). The shifting is more significant at a relatively higher wavelength. In conclusion, when the final temperature is to be controlled within a ±1 oC error and the iodide reagent strength is sufficient, the colorimetric approach can provide a precise and reliable tool for the determination of oxygen at the naturally occurring concentration range (up to 300 μM) in the ocean environment.
48
Maggeni, Avigail, and 馬艾薇. "Qualitative Analysis of Seawater desalinationAs a Sustainable Water Strategy: Israel as a Case Study." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/92104594693589279052.
Повний текст джерелаАнотація:
碩士國立臺灣大學
企業管理碩士專班
101
Climate change, increase in population size, and the rising standard of living, have put extensive pressure on natural water sources. The State of Israel, located in a semi- arid region, suffers from a negative water balance which means the consumption of water is higher than the supply. In order to close this gap between supply and demand for water, many different solutionshave been examined. This work presents the water economy in Israel, the main possible solutionsto the water shortage, and focuses on seawater desalination as the main alternative for increasing the water supply. A qualitative analysis was performed on the different benefits and limitations of seawater desalination, using reliable and scientific data. The conclusion drawn from this research is that seawater desalination is the most `sustainable solution for the water shortage in Israel, offering an unlimited amount of water for the entire population. Nevertheless, some issuesneed to be taken into consideration if the option of seawater desalination is chosen. The location of the desalination plant should not harm any population centers, and occupation of available seashores should be avoided as much as possible, giving priority to industrial zones as the preferred locations. In addition, a proper long-term monitoring of the salt and chemicals discharged back into the sea in the desalination process must take place, identifyingany potential damages to marine- life and seawater quality.
49
Chiu, Chao-yuan, and 邱昭源. "A Study of Planning for Seawater Desalination Process - A Case Study in the Hsinchu Science-based Industrial Park." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/36697277147225156913.
Повний текст джерелаАнотація:
碩士國立臺灣大學
環境工程學研究所
91
Due to the supply of water resource is unstable in Taiwan area, a water-shortage situation always happens in Winter and Spring. It will threaten or damage production if that situation occurs in the Hsinchu Science-based Industrial Park. To solve water-shortage risk of the Hsinchu Science-based Industrial Park , this research attempt to plan a most proper seawater desalination process for Hsinchu Science-based Industrial Park. With the usage of the scoring model in quantitative approach to decision making as a tool, we can assess seawater desalination processes and then obtain the most proper one. Finally, this research will conduct a preliminary evaluation to seawater desalination process by a assessment which integrates scoring model and complete comparison according to eight criteria. we find out the highest degree of satisfaction among four processes is reverse osmosis(RO) process by the above result calculated with each importance percentage of criteria. And the number two is multi-stage flash(MSF) distillation. The number three is vapor compression distillation(VCD). The last one is multiple effect distillation(MED). Therefore according to the result of assessment through the scoring model, the conclusion of this study proposes the most proper seawater desalination process for the Hsinchu Science-based Industrial Park is reverse osmosis process.
50
Chou, Meng-Hsien, and 周孟賢. "The study of MWCNTs composite material coated by EPD as cathode electrodes for seawater batteries." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/73669657608792577235.
Повний текст джерелаАнотація:
碩士國立清華大學
材料科學工程學系
102
In this experiment, multi-walled carbon nanotubes (MWCNTs) are coated onto stainless steel mesh by electrophoretic deposition and assemble a seawater battery cell with magnesium/aluminum alloy as anode and MWCNTs/stainless steel composite as cathode. We find that MWCNT coating reduces internal resistance and facilitates charge transfer at electrode/electrolyte interfaces, allowing seawater batteries to yield higher current and stable voltage output. Meanwhile, no pollutants are released into seawater while discharging.