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1
Woodhouse, Oliver Brian. "Osmium in seawater : analysis and geochemistry". Thesis, University of Southampton, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.284676.
Testo completo
2
Quigley, M. N. "Co-precipitation and flameless A.A.S. studies in seawater analysis". Thesis, University of Salford, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.372136.
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3
Colombo, Carlo Maurizio. "Flow analysis of trace metals in seawater by voltammetry". Thesis, University of Liverpool, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.338581.
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4
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.
Testo completoAbstract (sommario):
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.
5
Mohamed, Hassan S. B. Massachusetts Institute of Technology. "A numerical analysis of condenser performance of a seawater desalination system". Thesis, Massachusetts Institute of Technology, 2009. http://hdl.handle.net/1721.1/54517.
Testo completoAbstract (sommario):
Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2009.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 31).
This thesis presents the numerical analysis of three type condensers for desalination of seawater system. The condensers that were analyzed were a finned tube condenser that was built in Malaysia desalination plant, a cooling tube condenser in Jordan, and a common plate finned tube condenser. The goal of the analysis is to observe the thermal performance parameters of a condenser such as heat and mass transfer coefficient, surface effectiveness and condensate flow rate. The parameters that were changed in the analysis were the face velocity of air, the water velocity, and the number of rows of tubes. The numerical analysis was done based on basic heat exchanger analysis using e-NTU method for a dry case, and using a j-factor correlation that was developed by McQuiston for studying the wet case. Results from the basic heat exchanger analysis showed the air humidity ratio profile and temperature profile of air and water at the outlet of the condenser. The exit air temperature and humidity ratio were inversely proportional to the length of the condenser, whereas the temperature of the water at the outlet was proportional to the length of the condenser. Results from the j-factor correlation method show that the heat and mass transfer coefficient of the system increased when the number of rows of tubes, face velocity and water velocity increased. Similarly, the analysis showed that the condensate flow rate was highly influenced by the face velocity. In addition, the surface effectiveness was inversely proportional to the face velocity.
by Hassan Mohamed.
S.B.
6
Tappin, Alan David. "Studies of trace metals in shelf waters of the British Isles". Thesis, University of Southampton, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.330182.
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7
Couture, Estelle. "Chlorate and chlorite analysis in seawater, chlorate sinks, and toxicity to phytoplankton". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape17/PQDD_0023/MQ36420.pdf.
Testo completo
8
Al-Rashidi, Thamer Badi. "An analysis of drivers of seawater temperature in Kuwait Bay, Arabian Gulf". Thesis, University of Southampton, 2009. https://eprints.soton.ac.uk/145867/.
Testo completoAbstract (sommario):
Kuwait Bay presents a unique ecosystem and a significant nursery ground for many fish and shrimp species. In the last three decades, the bay has been under pressure from urbanization as well as from development from the entire region of the Arabian Gulf. Seawater temperature has an important impact on the marine environment. The aim of this study is to evaluate the drivers of seawater temperature in Kuwait Bay over the last two decades. Moderate Resolution Imaging Spectroradiometer (MODIS) and Landsat satellites images were used to describe the spatial and temporal distribution of sea surface temperature (SST) in the Arabian Gulf and Kuwait Bay. Hourly temperature measurements collected during the winter, 2007 and summer, 2008 were used to define the vertical temperature gradient in the water column, sea-bed and the intertidal flats of Kuwait Bay. Advanced Very High Resolution Radiometric (AVHRR) satellite data collected between 1985 and 2007 was also used to study the trends and drivers of increasing SST in Kuwait Bay over the last two decades. Satellite imaging showed that generally SST of Kuwait Bay is higher in the south than in the north. Highest SST was recorded near local human activities especially close to power and desalination plants due to thermal discharges. The field measurements showed that the water temperature is well-mixed in the bay. Seawater temperature reached 37 ºC in summer and dropped to 15.2 ºC in winter. Measurements beneath the sea-bed and within the intertidal flats showed that the temperature increased with depth in winter and decreased in summer. In winter, the sea-bed and intertidal flats are a source of heat to the water column, during summer the opposite is true. AVHRR data showed that the seawater temperature increased in Kuwait Bay by 0.62 (± 0.01)ºC/decade in the last two decades. This trend is three times greater than the global average. The defined trends were substantiated by routine in situ monthly measurements of SST made by the EPA in the bay, and were also similar in pattern and trend to air temperature recorded at Kuwait airport. Temperature trends have been affected by drivers, conveniently sub-divided into global (which contributes 37% of the change), regional (which contributes 50% of the change) and local (which contributes 13% of the change). SST measurements showed peaks in summer temperature coincident with El Niño events in 1998 and 2003. The measurements also showed a relatively-low summertime peak during 1991 in the aftermath of Iraqi invasion of Kuwait due to atmospheric dimming brought about by dense smoke that persisted in the region for most of that year. The long term trend also showed a drop in temperature after 2004 as a result of increasing dust storm frequency in the region. Air temperature was found to be the most dominant driver of seawater temperature in Kuwait Bay and operates at a regional scale. At the local scale the seawater temperature of Kuwait Bay is influenced by intertidal flat exposure time and the thermal discharge from power and desalination plants.
9
Winhusen, Eric. "PRECAMBRIAN SEAWATER TEMPERATURE ANALYSIS USING OXYGEN ISOTOPES FROM HAMERSLEY CARBONATES, WESTERN AUSTRALIA". University of Cincinnati / OhioLINK, 2001. http://rave.ohiolink.edu/etdc/view?acc_num=ucin992268720.
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10
Tan, KengSoong. "Electrochemical analysis of the erosion corrosion of HVOF aluminium bronze coatings". Thesis, University of Southampton, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.274707.
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11
Wong, King-wai Kelvin, e 黃景瑋. "Proteome response of barnacle larvae to CO2-driven seawater acidification". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2011. http://hub.hku.hk/bib/B46475084.
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12
Tian, Feng, e n/a. "The organic complexation of iron in seawaters around New Zealand". University of Otago. Department of Chemistry, 2006. http://adt.otago.ac.nz./public/adt-NZDU20070117.091325.
Testo completoAbstract (sommario):
This project aimed to characterise the organic speciation of iron in various oceanic waters associated with the New Zealand marine environment, and to examine the possible production of natural organic Fe-binding ligands by the Southern Ocean phytoplankton Phaeocystis antarctica. The location of New Zealand at the edge of the Southern Ocean provides a natural laboratory for studying ocean processes in a variety of oceanic conditions.
A time series of a surface transect across the Otago Continental Shelf was undertaken between April 2002 and January 2005 to measure the organic complexation of iron, hydrographic parameters and macronutrient concentrations. The study area contains three distinct water masses: 1) neritic water; 2) the Southland Current, derived from the Subtropical Surface Water (STW); 3) Subantarctic Surface Water (SASW). Hydrological measurements outlined the positions of the three water masses as being fixed within predictable boundaries. Variations in nutrient concentrations in the study area indicated that SASW is the predominant source of nitrate and phosphate to the shelf. Dissolved iron concentrations dropped sharply seaward from several nanomolar to sub-nanomolar levels. The dissolved iron was fully complexed with strong organic ligands in all three water masses, and the ligand concentrations also showed a slightly seaward decreasing trend. Trends in dissolved iron and the iron-binding ligand concentrations related to season were only obvious in neritic waters. Concentration maxima occurred during late spring and summer months, and concentration minima occurred in the middle of each year (winter months). Dissolved iron concentration was low (~0.1 nM) in SASW year round. Data from the present study are in support of that the SASW as a whole is classified as a high nitrate low chlorophyll (HNLC) water body and has an iron-limited phytoplankton population.
East of the New Zealand landmass, the Subtropical Convergence (STC) is topographically locked to the Chatham Rise. This is a dynamic region of enhanced primary production (Bradford-Grieve et al., 1997), which separates macronutrient-depleted STW from macronutrient-replete SASW. Dissolved iron concentrations were low (~0.1-0.2 nM) in SASW, while elevated dissolved iron concentrations were observed at the north flank of the Chatham Rise. The iron data imply that the regional currents may be an important vehicle for transporting the elevated iron across the front. Total dissolved iron-binding ligand concentrations were consistently higher (~0.5 nM) in the STW and STC waters than in SASW. The discrepancy in the ligand concentrations between STW and SASW may reflect a different contribution to the ligand pool from the local planktonic community.
The organic complexation of iron in the oligotrophic subtropical water columns in the Tasman Sea was also studied and comparison of waters to the north and south of the Tasman front were reported. The iron speciation data imply the potential biological origin for the iron-binding ligands, and the difference in ligand concentrations across the Tasman Front may represent slight differences in algal biomass.
A limited investigation to examine the production of natural organic iron-binding ligands by the Southern Ocean phytoplankton Phaeocystis antarctica was undertaken in laboratory culture experiments. Release of nanomolar levels of a strong iron-binding ligand was detected by cathodic stripping voltammetry (CSV) even under relatively high iron concentrations (> 1nM). The estimated iron binding strength for the ligands was similar to those observed in the open ocean. Moreover, the kinetic data suggested the presence of another weaker ligand class, which had a higher Fe concentration (>2 nM) and was not detectable by the CSV ligand titration technique.
Our field observations and culture experiment results suggest that the Fe-binding ligands are biologically produced. It appears algae engineer their environment to make Fe more available/accessible for longer by producing these ligands. Therefore, the organic speciation of Fe plays a very important role in the sustained nutrition of ocean primary productivity and must be accounted for in geochemical modelling.
13
Easley, Regina Anita. "The Spectrophotometric Analysis of Lead Carbonate Complexation and Carbonate Saturation States in Seawater". Scholar Commons, 2013. http://scholarcommons.usf.edu/etd/4668.
Testo completoAbstract (sommario):
The carbon dioxide (CO2) system is the primary buffer in seawater which controls oceanic pH. Changes in the marine CO2 system affect a number of processes such as metal speciation, mineral saturation states, auditory responses in fish, and primary productivity rates. Increased atmospheric concentrations of CO2 from human activities (e.g. burning of fossil fuels, deforestation, and cement production) has led to a global decrease in surface ocean pH termed anthropogenic ocean acidification. One particular concern in response to increased oceanic CO2 is a substantial decrease in the calcium carbonate (CaCO3) saturation states, ΩCaCO3. The long-term physiological effects of ocean acidification and decreased ΩCaCO3 on marine biota are currently subjects of intensive global investigation. Consequently improved methods are needed to facilitate evaluations of the evolving CO2 system chemistry and the responses of marine organisms to those changes.
Currently two of four measureable chemical parameters (pH, dissolved inorganic carbon, fugacity of CO2, and total alkalinity) are required for full characterization of the inorganic CO2 system; carbonate ion concentrations ([CO3 2-]) can, for example, be calculated from paired measurements of pH-DIC and pH-TA. The primary objective of this dissertation is to refine a method for directly determining [CO3 2-] using a single measurement, the distinctive ultraviolet absorbance spectra of Pb(II) species in seawater. The technique is fast, methodologically simple, and suitable for routine use in laboratory and shipboard studies. It is, as well, suitable for analyses using autonomous instrumentation. My studies began with an investigation of lead carbonate (PbCO3 0) complexation in synthetic media (at 25 °C between 0.001 to 5.0 molal ionic strength) to evaluate factors that control Pb(II) speciation, and thereby Pb(II) spectra, in seawater. Since laboratory investigations of Pb(II) speciation in seawater require potentiometric measurements of seawater pH, my dissertation includes development of a novel spectrophotometric method for calibrating pH electrodes directly in seawater. This spectrophotometric electrode calibration enables improved assessment of the extent to which electrode behavior is Nernstian and the influence of salinity on electrode calibrations. In addition, for the first time at sea, [CO3 2-] was directly determined in the Arctic and the Eastern Pacific Oceans using the Pb(II) method. These field studies allowed assessment of the consistency between direct [CO3 2-] determinations and carbonate determined using conventional CO2 system measurements. Finally, using techniques from my evaluation of lead speciation, as well as my electrode calibration development and field studies, additional laboratory studies were used to increase carbonate measurement sensitivity and applicability over a wider range of salinity.
14
Diaz, Julia M. "Inorganic polyphosphate in the marine environment: field observations and new analytical techniques". Diss., Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/43673.
Testo completoAbstract (sommario):
Phosphorus (P) is a requirement for biological growth, but this vital nutrient is present at low or limiting concentrations across vast areas of the global surface ocean. Inorganic polyphosphate (poly-P), a linear polymer of at least three orthophosphate units, is one component of the marine P cycle that has been relatively overlooked as compared to other P species, owing in part to a lack of routine analytical techniques that cleanly evaluate it within samples. This thesis demonstrates that inorganic poly-P is a quantitatively significant and dynamic component of the global marine P cycle while also establishing two new techniques for its analysis in biological and environmental samples. In Chapter 2, experiments using the freshwater algae Chlamydomonas sp. and Chlorella sp. illustrate X-ray fluorescence spectromicroscopy as a powerful tool for the sub-micron scale assessment of poly-P composition in organisms. This method enabled the discovery, detailed in Chapter 3, of a mechanism for the long-term sequestration of the vital nutrient P from marine systems via the initial formation of poly-P in surface waters and its eventual transformation into the mineral apatite within sediments. The importance of marine poly-P is furthermore established in Chapter 3 by observations showing that naturally-occurring poly-P represents 7-11% of total P in particles and dissolved matter in Effingham Inlet, a eutrophic fjord located on Vancouver Island, British Columbia. In Chapter 4, a new fluorometric protocol based on the interaction of inorganic poly-P with 4',6-diamidino-2-phenylindole (DAPI) is established as a technique for the direct quantification of poly-P in environmental samples. Chapter 5 presents work from Effingham Inlet utilizing this method that show that inorganic poly-P plays a significant role in the redox-sensitive cycling of P in natural systems.
15
岑永昌 e Wing-cheong Sham. "The determination of mercury in sediment, river water and seawater samples, and the determination of Cr(VI) in river water". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1991. http://hub.hku.hk/bib/B31210533.
Testo completo
16
Hudson, Edward D. "The biogeochemistry of sterols in Trinity Bay, Newfoundland, and a new method (thin layer chromatography-pyrolysis-gas chromatography-mass spectrometry) for their analysis". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp03/MQ47458.pdf.
Testo completo
17
Saravanabhavan, Gurusankar. "Analysis of steroid hormones as endocrine disruptors in sewage, seawater and mussels using GC-MS techniques /". Internet access available to MUN users only, 2003. http://collections.mun.ca/u?/theses,175261.
Testo completo
18
Howell, William R. N. "An analysis of possible microbiologically influenced crevice corrosion of 316 stainless steel in a seawater environment". Thesis, Monterey, California. Naval Postgraduate School, 1996. http://hdl.handle.net/10945/7939.
Testo completoAbstract (sommario):
An analysis was conducted of 316 Stainless Steel components which exhibited an unusual degree of crevice corrosion after exposure to seawater for approximately one year. After conducting research into the possible chemical and microbiological mechanisms for the corrosion, a metallurgical and microscopic examination of the components was performed. Results of these examinations indicated that the corrosion observed was probably the result of an interaction between the Gallionella aerobic iron bacteria and the anaerobic sulfate reducing bacteria Desulfovibrio and Desulfomaculum
19
Howell, William R. N. (Robert Newton). "An analysis of possible microbiologically influenced crevice corrosion of 316 stainless steel in a seawater environment". Thesis, Massachusetts Institute of Technology, 1996. http://hdl.handle.net/1721.1/39622.
Testo completo
20
Un, Ka Man. "Real-time ocean optical fiber sensing of phytoplankton for studies in size distribution, concentration and biomass". HKBU Institutional Repository, 1999. http://repository.hkbu.edu.hk/etd_ra/265.
Testo completo
21
Rentel, Raimund. "Development and implementation of a flow injection analyser with chemiluminescence for detection of sub-nanomolar Fe in seawater". Thesis, Stellenbosch : Stellenbosch University, 2014. http://hdl.handle.net/10019.1/95832.
Testo completoAbstract (sommario):
Thesis (MSc)--Stellenbosch University, 2014.ENGLISH ABSTRACT: Iron is an essential micronutrient for all phytoplankton and is found in seawater at picomolar-level concentrations. For the first time in South Africa, a technique that utilizes a flow injection analyser (FIA) coupled with a chemiluminescence reaction has been developed for the analysis of Fe in seawater samples. The developed method is an improvement on similar available methods and uses commercially available resin (IDA) as opposed to the one that requires synthesis in the laboratory. Furthermore, the method requires reduced reagent concentrations thereby providing better results in a cost-efficient and easy manner. The improvements resulted in better precision while eliminating the loss of resin through bleeding, a common problem when using 8-HQ resin as per prior methods. Method validation was performed using internationally calibrated reference material provided by GEOTRACES and the values obtained were within the error limits of certified range. An inter-laboratory calibration was also conducted as part of the verification of the system. Surface samples from the SANAE 51 cruise were analysed for dFe and TdFe. Subsequently, the method was implemented on the SANAE 53 voyage on board the SA Agulhas II, to assess trace metal sampling protocol for any contamination issues, as well as for the analyses of collected samples. Current results suggest some contamination during collection stages, but this is still to be verified by complementary data on macronutrients and chlorophyll. The method was successfully developed and implemented in a land based clean laboratory, as well as on board a vessel.
AFRIKAANSE OPSOMMING: Yster is „n noodsaaklike mikrovoedsel vir fitoplankton en word in seewater in pikomolêre konsentrasies gevind. Hierdie lae konsentrasies en potensiële besoedeling gedurende monsteropname vanaf „n skip se platform maak akkurate Fe-analise moeilik. Vir die eerste keer in Suid-Afrika is „n tegniek ontwikkel wat gebruik maak van „n vloei- inspuitinganaliseerder (VIA), met „n geassosieerde chemiluminessensiereaksie, om die analise van Fe in seewatermonsters uit te voer. In teenstelling met soortgelyke bestaande metodes wat labratorium-gesintetiseerde hars vereis, is die nuut-ontwikkelde metode „n verbetering wat gebruik maak van „n kommersieel-beskikbare hars (IDA). Verder vereis die metode verminderde reagenskonsentrasies wat sodoende beter resultate lewer op 'n koste-effektiewe en eenvoudiger wyse. Die verbeteringe het gelei tot verhoogde akkuraatheid en uitskakeling van die verlies van hars deur dreinering – „n algemene probleem wat ondervind is met die gebruik van 8-HQ hars in vorige metodes. Geldigheidsbepaling van die metode is met internasionaal-gekalibreerde verwysingsmateriaal, verskaf deur GEOTRACES, uitgevoer. Die waardes wat verkry is, was binne die foutgrense van die gesertifiseerde skaal. „n Interlaboratorium-kalibrasie is ook uitgevoer as deel van die verifikasie van die stelsel. Daarna is die metode geïmplementeer gedurende die SANAE 53 reis op die SA Agulhas II, om die spoormetaal-monsternemingprotokol vir enige besoedelingskwessies te evalueer, asook vir die ontleding van versamelde monsters. Huidige resultate dui op „n mate van besoedeling tydens die versamelingstadiums, maar dit moet nog geverifieer word deur aanvullende data van die totale oplosbare Fe, makrovoedingstowwe en chlorofil.
22
Newton, M. P. "The design and application of an instrument for the automated in-line measasurement of trace metals in seawater using chronopotentiometric stripping analysis". Thesis, University of Liverpool, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.233822.
Testo completo
23
Esposito, Mario. "Stable carbon isotope analysis of seawater samples : a new approach to assess CO2 effects on the marine carbon cycle". Thesis, University of Southampton, 2017. https://eprints.soton.ac.uk/412277/.
Testo completoAbstract (sommario):
Stable isotope ratio analyses offer a unique opportunity to obtain information about ecosystem dynamics, patterns and processes. The anthropogenic contribution to the global atmospheric CO2 rise through fossil fuel combustion, deforestation and other related human activities has changed the stable carbon isotope composition (δ13C) of the atmosphere over the past 200 years. Changes in the carbon isotopic patterns of terrestrial biosphere, lithosphere and oceans are also expected. The global ocean has been acting as a net sink for CO2 emissions and although it moderates the climate, it is currently in a critical state of health. While the physico-chemical consequences (ocean acidification) of the increasing CO2 uptake by the ocean are fairly well known, the perturbation to marine ecosystems and the related effects on biota still entail large uncertainties. This thesis investigates the feasibility of using measurements of δ13C of seawater samples to increase our understanding of the biogeochemical responses of marine ecosystems to human CO2 perturbation. The isotopic composition of all the individual inorganic and organic carbon species from three long term mesocosm experiments (Sweden 2013, Gran Canaria 2014, Norway 2015) was determined. To have accurate and precise isotopic measurements, mass spectrometry instrument calibrations and method validation procedures were performed. Universal and inter-laboratory accuracy of the analysis was assessed by running standard materials provided by the International Atomic Energy Agency (IAEA, Vienna) and by the Scottish Universities Environmental Research Centre (SUERC) stable isotope laboratory, respectively. Precision and internal consistency was assessed from isotopic measurements of seawater reference materials from A.G. Dickson and D. Hansell for dissolved inorganic and organic carbon, respectively. A novel accurate, precise and rapid method, coupling a Shimadzu 5000A total organic carbon (TOC) analyser to an isotope ratio mass spectrometer (Thermo Scientific Delta V Advantage IRMS), was successfully developed in order to determine the δ13C of dissolved organic carbon in seawater samples which, due to analytical challenges, is currently not a widespread technique. The combination of isotopic and non-isotopic measurements from mesocosm experiments provided a holistic view of the biogeochemical mechanisms that affect carbon dynamics under different CO2 conditions (up to 2000 ppm). A clear CO2 response was detected in the isotopic datasets, but increased CO2 levels had only a subtle effect on the concentrations of the dissolved and particulate organic carbon pools. Distinctive δ13C signatures of the particulate carbon pool both in the water column and the sediments were detectable for the different CO2 treatments and they were strongly correlated with the δ13C signatures of the inorganic carbon but not with the δ13C of the dissolved organic pools. Phytoplankton fractionation was positively affected by high CO2 either because of the higher CO2 availability or because of a shift in phytoplankton community composition, however, phytoplankton bloom intensity and evolution was independent of CO2 concentrations and higher CO2 levels had no significant effect on inorganic nutrient uptake or carbon production/consumption. Overall this study proved the stable carbon isotope approach to be an effective tool for the assessment of the major biogeochemical interactions among individual compartments within the marine system opening the door to new interpretations for past, present and future changes of the global carbon cycle.
24
Johnson, Aaron W. "Regional-scale geochemical analysis of carbonate cements : reconstructing multiple fluid interactions related to dolomitization and mineralization in lower carboniferous rocks of the Irish Midlands /". free to MU campus, to others for purchase, 2003. http://wwwlib.umi.com/cr/mo/fullcit?p3101027.
Testo completo
25
Abbott, William. "The Development of a Fluorescence-based Reverse Flow Injection Analysis (rFIA) Method for Quantifying Ammonium at Nanomolar Concentrations in Oligotrophic Seawater". Scholar Commons, 2015. http://scholarcommons.usf.edu/etd/5892.
Testo completoAbstract (sommario):
The goal of this thesis was to adopt a reverse flow injection analysis (rFIA) technique to the fluorometric analysis of the reaction o-phthaldialdehyde (OPA) with ammonium, allowing accurate measurements of ammonium concentrations lower than the detection limit of the widely used indophenol blue (IPB) colorimetric method while accounting for the background fluorescence of seawater. Ammonium is considered an essential nutrient for primary productivity, especially in the nutrient depleted surface ocean where as the most reduced form of dissolved inorganic nitrogen, it is readily assimilated via metabolic pathways. Challenges in the quantification of ammonium require more sensitive analytical techniques for a greater understanding of the biogeochemical cycling of ammonium in the oligotrophic ocean. On-line and automated flow analysis techniques are capable of mitigating some of the challenges. Fluorescent-based methods out-perform colorimetric methods in terms of detection limits and sensitivity. Presented here is the development of an rFIA technique paired with an OPA-sulfite chemistry. For this method, a sulfite-formaldehyde reagent is mixed with the sample stream and then injected with the OPA reagent before being heated. Fluorescence is measured before and at the peak of the OPA injection, differentiating the background fluorescence from the analyte signal. Experiments to optimize reaction parameters and characterize the effects of salinity and potentially interfering species were conducted. The newly developed method offers a reasonable throughput (18 samples per hour), low limit of detection (1.1 nM) ammonium analysis technique with automatic background fluorescence correction suitable for oligotrophic seawater as a preferable alternative to the low sensitivity and high limit of detection IPB colorimetric method.
26
Guirguis, Mageed Jean. "Energy Recovery Devices in Seawater Reverse Osmosis Desalination Plants with Emphasis on Efficiency and Economical Analysis of Isobaric versus Centrifugal Devices". Scholar Commons, 2011. http://scholarcommons.usf.edu/etd/3135.
Testo completoAbstract (sommario):
With huge demands for potable water in regions lacking fresh water sources such as surface or ground water, various potential technologies have been explored for eliminating water shortage. Seawater emerged as a potential source and a major lifeline for such water-deprived areas. The development of seawater reverse osmosis (SWRO) technology proved to be a groundbreaking innovation, making it easier to extract pure water from seawater. Ever since its inception, SWRO technology has taken many leaps towards the development of energy efficient and high yielding systems. The reduction in energy consumption of desalination plants that were based on the SWRO technology emerged as a major driver of the technology revolution in this field. The improvement of membrane life and salt rejection, increase in recovery, and decrease in energy consumption has been the primary criteria for sifting through available technologies for incorporation in desalination plants. Many developments have, ever since, occurred in this direction. The membrane life has multiplied and the Total Dissolved Solids in the product are now as low as 100 mg/L. In addition, recoveries of 40-50% have been achieved. By recycling energy, many SWRO desalination plants have significantly lowered their total energy consumption. With the help of energy recovery devices (ERDs), it is now possible to decrease power consumption and increase efficiency of the seawater reverse osmosis desalination plant.
The first large-scale municipal SWRO plant was installed in 1980 in Jeddah, Saudi Arabia. This plant consumed 8 kilowatt-hours energy per cubic meter of water produced. This consumed energy was less than half of what was usually consumed by other conventional distillation processes. However, the SWRO desalination technology has one disadvantage. The seawater, which is to be desalinated, is pressurized with the help of high-pressure pumps. A large amount of energy is consumed during this process. Once the desalination is complete, the remaining reject water has to be eliminated as waste. Since the brine reject produced in this process has a high pressure, simply dumping it back into the sea is a waste of energy. This pressure can be reused and thus, the energy could be recycled. This idea led to the innovation of energy recovery devices (ERDs) that prevent the wastage of energy in the SWRO process. The hydraulic energy in the highly pressurized reject brine can be re-used with the help of ERDs, and energy consumption can thus be reduced by significant high amounts. The development of ERDs helped in the set-up and operation of large-scale SWRO plants, and facilitated the economic viability of the desalination process. The energy requirements of conventional SWRO plants are presently as low as 1.6 kWh/m3, making the process more cost effective and energy efficient than other technologies. About 80% of the total cost of desalinated water is due to energy consumption and capital amortization. The remaining costs are associated with other maintenance operations such as replacement of membranes and other components, labor associated costs etc.
Since energy consumption is the main determinant of final costs of the product, increasing energy efficiency of the plants is of primary concern. This paper deals with various energy recovery devices such as the Francis turbine, Pelton wheel, turbocharger, Recuperator, DWEER and Pressure Exchanger, used in SWRO desalination plants along with case studies associated with each of these. Special focus is given to the energy efficiency and costs associated with these devices. A brief discussion of the devices that are currently under investigation is also provided in the conclusion.
An analysis of isobaric versus centrifugal devices is also conducted in this work. A comparison between the energy recovery turbine (ERT) manufactured by Pump Engineering Inc. (PEI) and the pressure exchanger (PX) manufactured by Energy Recovery Inc. (ERI) energy recovery systems is performed using collected data from provided water analyses and respective manufacturers' device specifications. The different configurations used for this comparison were applied to the Jeddah SWRO desalination plant for a total productivity of 240,000 m³/day. As a result of this analysis, the specific energy consumption of the ERT and PX configurations were 2.66 kWh/m3 and 2.50 kWh/m3 respectively. Analysis shows however that although the PX configuration achieved the best specific energy consumption, the ERT was favored over it due to its lower capital and maintenance costs. Therefore, the final conclusion of this work, in this special case, is that the ERT configuration is more economical than the PX configuration.
27
SEO, DANIELE. "Avaliação dos teores de Br, Cl, K, Mg, Mn e V em mexilhões Perna perna (Linnaeus, 1758: Mollusca, Bivalvia) coletados no litoral do estado de São Paulo, Brasil". reponame:Repositório Institucional do IPEN, 2012. http://repositorio.ipen.br:8080/xmlui/handle/123456789/9939.
Testo completoAbstract (sommario):
Made available in DSpace on 2014-10-09T12:33:02Z (GMT). No. of bitstreams: 0Made available in DSpace on 2014-10-09T14:06:05Z (GMT). No. of bitstreams: 0
Dissertação (Mestrado)
IPEN/D
Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
28
Santos, Luiz Queiroz dos. "Modelagem e aproximação numérica de dados de nutrientes na costa pernambucana". Universidade Católica de Pernambuco, 2010. http://www.unicap.br/tede//tde_busca/arquivo.php?codArquivo=549.
Testo completoAbstract (sommario):
A zona costeira de Pernambuco compreende uma faixa de 187 km de extensão e abrange 21 municípios. Apresenta o maior aglomerado populacional do Estado, onde está
concentrada aproximadamente 44 % da população. Pesca intensiva e poluição ambiental, aliadas a uma mudança de clima global conduzirão a um colapso de todos os pescados em
2048. Esses impactos ambientais alteram a concentração ou distribuição de nitrogênio, fósforo e silício (biolimitantes da produção primária) e interferem em seus ciclos
biogeoquímicos. A aplicação de modelos numéricos a zonas costeiras pode indicar uma previsão melhor dos fluxos de nutrientes associados com suas transferências e
conseqüência geoquímica. O objetivo deste trabalho foi estimar concentrações dos principais nutrientes dissolvidos: nitrogênio, fósforo e silício através de modelagem
matemática. Na metodologia foram utilizados dados do Programa REVIZEE, coletados pelo Departamento de Oceanografia (UFPE) no verão pernambucano de 1997. As estimativas das concentrações dos nutrientes nitrogênio, fósforo e silício da costa marinha no estado de
Pernambuco geram informações que dão suporte à atividades futuras de pesca artesanal. O apoio científico serve de suporte para o aumento da demanda pesqueira que é de produção econômica para a região, considerando ser a mesma uma zona costeiraThe coastal zone of Pernambuco comprises a range of 187 km and covers 21 cities. It presents the greatest agglomeration of the state, which concentrates approximately 44% of the population. Overfishing and pollution environment, coupled with global climate change will lead to a collapse of all fish in 2048. These environmental impacts change the concentration or the distribution of nitrogen, phosphorus and silicon (limiting production primary). It also interferes in their biogeochemical cycles. The application of numerical models in coastal areas may indicate a better estimate of nutrient fluxes associated with their transfer and geochemistry consequence. The objective of this study was to estimate concentrations of the major nutrients:nitrogen, phosphorus and silicon through mathematical modeling. In the methodology it was used the data Program REVIZEE, collected by the Department of Oceanography (UFPE) in the summer of 1997. The estimates of concentrations of nitrogen, phosphorus and silicon from the sea coast in the state of Pernambuco generated information to support the future activities of fishing. The scientific support for the increased demand of fishing is related to the economic production of the coastal area region
29
Paluselli, Andrea. "Analysis, occurence, release and degradation of phthalate esters (PAEs) in Mediterranean coastal sea". Thesis, Aix-Marseille, 2018. http://www.theses.fr/2018AIXM0060/document.
Testo completoAbstract (sommario):
Les phtalates (PAEs) sont un groupe de contaminants organiques émergents qui sont devenus une préoccupation majeure en raison de leur omniprésence dans le milieu marin et de leurs effets perturbateurs sur le système endocrinien. Cependant, leur répartition en Méditerranée est assez mal connue, principalement en raison des difficultés analytiques et du risque élevé de contamination des échantillons lors du processus analytique. En outre, les débris de plastique en milieu marin contiennent des additifs comme les PAEs, qui sont ajoutés lors de l’étape de fabrication du plastique. Dans la première partie de cette thèse, une méthode analytique a été optimisée et validée pour la détermination de 8 PAEs à l'état de traces en milieu marin. Brièvement, 1L d'échantillon filtré est passé à travers des cartouches de verre contenant 200 mg d'Oasis HLB, puis élué à l’aide de 6mL d'acétate d'éthyle. Notre méthode donne des rendements d’extraction compris entre 95 et 115 % et des blancs acceptables. Dans un second temps, un suivi annuel de la contamination de la Baie de Marseille a été effectué de décembre 2013 à novembre 2014. Les résultats ont montré la présence de 7 PAEs, avec des concentrations totales variant de 130 à 1330 ng L-1. Dans la dernière partie de cette thèse, deux échantillons de plastique communs (sac de poubelle et gaine de câble électrique) ont été incubés dans de l'eau de mer naturelle dans des conditions contrôlées de laboratoire, de manière à évaluer la migration de PAEs depuis ces matériaux en fonction de différentes conditions environnementales comme la température, la présence de lumière, ou encore la présence de bactériesPhthalic Acid Esters (PAEs) are a group of emerging organic contaminants that have become a serious issue because of their ubiquitous presence on the marine environment worldwide and for the endocrine disrupting effects in animals and humans. However, little is known about their distribution in the Ocean, mainly because of analytical difficulties and the high possibility of ambient sample contamination. Plastic debris in marine environment includes resin pellets, macro- and microplastic fragments, and contains additives such as PAEs that might be released in the aquatic environment in unknown proportion. In our work, we improved an analytical method for the determination of 8 PAEs, at trace levels in marine and fresh waters. In the first part of the thesis, the method was validated for different seawater salinities and wastewater treatment plant outlet. By passing 1 L of sample through glass cartridges packed with 200 mg of Oasis HLB and eluted with 6 mL of ethyl acetate, the recoveries of 8 PAEs ranged from 95 to 115 % with acceptable blank values (below 0.4-4.0 % of the masses measured in different seawater samples). In a second part, PAE distribution in the Marseille Bay has been evaluated though a one-year monitoring from December 2013 to November 2014. The results showed the occurrence of six PAEs with total concentrations ranging from 130 to 1330 ng L-1. In the last part of this thesis, two common plastic samples as trash plastic bags and insulation layer of electric cables were incubated in natural seawater in laboratory conditions and studied for the release of PAE. Release ws observed for the different PAEs with kinetics varying according to the plastic type
30
Capper, Joseph David. "Numerical Analysis and Parameter Optimization of Portable Oscillating-Body Wave Energy Converters". Thesis, Virginia Tech, 2021. http://hdl.handle.net/10919/103861.
Testo completoAbstract (sommario):
As a clean, abundant, and renewable source of energy with a strategic location in close proximity to global population regions, ocean wave energy shows major promise. Although much wave energy converter development has focused on large-scale power generation, there is also increasing interest in small-scale applications for powering the blue economy. In this thesis, the objective was to optimize the performance of small-sized, portable, oscillating-body wave energy converters (WECs). Two types of oscillating body WECs were studied: bottom hinged and two-body attenuator. For the bottom-hinged device, the goal was to show the feasibility of an oscillating surge WEC and desalination system using numerical modeling to estimate the system performance. For a 5-day test period, the model estimated 517 L of freshwater production with 711 ppm concentration and showed effective brine discharge, agreeing well with preliminary experimental results.
The objective for the two-body attenuator was to develop a method of power maximization through resonance tuning and numerical simulation. Three different geometries of body cross sections were used for the study with four different drag coefficients for each geometry. Power generation was maximized by adjusting body dimensions to match the natural frequency with the wave frequency. Based on the time domain simulation results, there was not a significant difference in power between the geometries when variation in drag was not considered, but the elliptical geometry had the highest power when using approximate drag coefficients. Using the two degree-of-freedom (2DOF) model with approximate drag coefficients, the elliptical cross section had a max power of 27.1 W and 7.36% capture width ratio (CWR) for regular waves and a max power of 8.32 W and 2.26% CWR for irregular waves. Using the three degree-of-freedom (3DOF) model with approximate drag coefficients, the elliptical cross section had a max power of 22.5 W and 6.12% CWR for regular waves and 6.18 W and 1.68% CWR for irregular waves. A mooring stiffness study was performed with the 3DOF model, showing that mooring stiffness can be increased to increase relative motion and therefore increase power.Master of Science
As a clean, abundant, and renewable source of energy with a strategic location in close proximity to global population centers, ocean wave energy shows major promise. Although much wave energy converter development has focused on large-scale power generation, there is also increasing interest in small-scale applications for powering the blue economy. There are many situations where large-scale wave energy converter (WEC) devices are not necessary or practical, but easily-portable, small-sized WECs are suitable, including navigation signs, illumination, sensors, survival kits, electronics charging, and portable desalination. In this thesis, the objective was to optimize the performance of small-sized, oscillating body wave energy converters. Oscillating body WECs function by converting a device's wave-driven oscillating motion into useful power. Two types of oscillating body WECs were studied: bottom hinged and two-body attenuator. For the bottom-hinged device, the goal was to show the feasibility of a WEC and desalination system using numerical modeling to estimate the system performance. Based on the model results, the system will produce desirable amounts of fresh water with suitably low concentration and be effective at discharging brine. The objective for the two-body attenuator was to develop a method of power maximization through resonance tuning and numerical simulation. Based on the two- and three-degree-of-freedom model results with approximate drag coefficients, the elliptical cross section had the largest power absorption out of three different geometries of body cross sections. A mooring stiffness study with the three-degree-of-freedom model showed that mooring stiffness can be increased to increase power absorption.
31
Glaude, Robin Francoise. "Applicability of Uncertainty analysis to groundwater environmental risks through Fault Tree Analysis and Monte Carlo simulations". Master's thesis, Alma Mater Studiorum - Università di Bologna, 2020.
Cerca il testo completoAbstract (sommario):
The Anthropocene epoch initiated by human in
uence on its Earth system (biosphere,
hydrosphere, ...) leads to an irreversible change: Global warming. Climate
change alters all existing natural processes, including the ones related to groundwater.
The present paper aims to study the occurrence's probability of two particular
groundwater risks: the generation of thermokarst lakes in permafrost environment
and its subsequent thermal consequences in the surroundings as well as seawater
intrusion inducing saltwater contamination in pumping wells. These processes are
dependent of physical parameters to which is attached uncertainty. Consequently,
two uncertainty analysis methods have been applied to determine the probability
of occurence of these undesired events: Fault Tree Analysis and Monte Carlo Simulation.
Beside the rough approximation performed to evaluate the probability of
thermokarst lake occurence (48%) and of talik development under these latter (73%)
by means of fault tree analysis, these high failure probabilities translate the urge to
slow down global warming due to the irreversible effect on permafrost environment,
meaning its thawing and releasing of trapped methane in the atmosphere. On the
other hand, Monte Carlo simulations have been performed to compare dfferent scenarii
related to seawater intrusion in Akrotiri aquifer in Cyprus. The results once
again translate the disastrous effect of climate change regarding the probability of
occurence of these unwanted events. Indeed, a failure probability around 6 times
greater (43%) is observed in the climate change scenario with respect to the reference
scenario (7%).
Uncertainty analysis is good methodology to apply to environmental concerns
to quantify the occurence's probability of these undesired events. This would urge
public authorities to perform decision making in order to avoid or reduce the failure's
probability of these groundwater issues that have irreversible consequences.
32
Ilioni, Alin. "Influence of seawater ageing on the behaviour of adhesives : a rapid characterization of the evolution of mechanical properties of bonded joints". Thesis, Brest, 2017. http://www.theses.fr/2017BRES0110/document.
Testo completoAbstract (sommario):
La majorité des adhésifs utilisés dans l’industrie marine sont des polymères avec un comportement mécanique qui est fortement influencé par les conditions environnementales (vieillissement hydrique ou température). Par conséquent, il est très important pour les ingénieurs travaillant dans des bureaux d’études d’être capable de prendre en compte ces effets lors des différentes étapes de développement et conception des assemblages collés.Le présent travail propose une méthode d’analyse de l’influence du vieillissement hydrique sur le comportement mécanique d’un adhésif structural époxy dans un assemblage collé. Tout d’abord, un modèle viscoélastique-viscoplastique a été développé pour caractériser la réponse mécanique de l’adhésif dans un joint de colle. Pour cela, le dispositif expérimentalArcan a été utilisé. Le modèle est identifié en utilisant la méthode d’identification inverse et les échantillons sont testés à l’état non-vieilli (pas de vieillissement hydrique). Les résultats obtenus après la démarche d’identification sont utilisés pour prédire le comportement mécanique d’éprouvettes massiques.Dans un deuxième temps, afin de diminuer les temps de saturation d’échantillons, l’évolution des propriétés mécaniques de l’adhésif est analysée sous différentes conditions de vieillissement hydrique (immersion dans l’eau de mer et en humidité relative contrôlée) grâce à des essais sur éprouvettes massiques.Les résultats obtenus seront utilisés pour identifier l’évolution de chaque paramètre du modèle proposé, en fonction de la quantité d’eau absorbée. En parallèle, un modèle de diffusion a été développé pour caractériser le gradient de teneur en eau des joints de colle. Les deux approches sont ensuite combinées pour modéliser les profils d’eau pour différents temps de vieillissement et prédire l’évolution des propriétés mécaniques du joint de colle après le vieillissement. Finalement, pour valider la méthode proposée, la prédiction du modèle est comparée avec des essais réalisés sur assemblages collés vieillisMost of the adhesives used in the marine industry are polymers with a mechanical behaviour which is strongly influenced by environmental conditions (water activity or temperature). Therefore, it is important for engineers and designers to be able to consider these effects during the different stages of development and manufacturing of a bonded structure.The present work presents a method for analyzing the influence of water ageing on the behaviour of an epoxy adhesive in an adhesively bonded assembly.First, a viscoelastic-viscoplastic model is developed to characterise the mechanical response of the adhesive at initial state in a bonded joint using the modified Arcan device. The model is identified using the inverse identification method and the considered samples are tested at an unaged stage (no water activity). The results obtained after the identification process are used to predict the bulk behaviour of the adhesive. A comparison between numerical results and experimental tests realised on bulk specimens is then made in order to validate this first approach.In a second phase, in order to decrease the times for samples saturation, the evolution of the mechanical properties of the adhesive in bulk form is tested under different water ageing conditions (immersion in seawater and different relative humidity). The obtained results allowed to identify the evolution of the model parameters as a function of water content. In parallel, a diffusion model was developed to characterise the water ingress in the bonded joint. These two approaches are then combined to model the water profiles and to consider the evolution of mechanical properties of a water aged adhesively bonded assembly, for different immersion times. Finally, to validate the framework, the prediction is compared with experimental tests performed on aged specimens
33
Deshpande, Jaydeep Sanjeev. "Investigations on Solar Powered Direct Contact Membrane Distillation". Thesis, Virginia Tech, 2016. http://hdl.handle.net/10919/71370.
Testo completoAbstract (sommario):
Desalination is one of the proposed methods to meet the ever increasing water demands. It
can be subdivided into two broad categories, thermal based desalination and electricity based
desalination. Multi-effect Distillation (MED), Multi-Stage Flashing (MSF), Membrane
Distillation (MD) fall under former and Reverse Osmosis (RO), Electro-Dialysis (ED) fall under
later. MD offers an attractive solution for seawater as well as brackish water distillation. It shows
highly pure yields, theoretically 100% pure. The overall construction of a MD unit is way simpler
than any other desalination systems.
MD is a thermally driven diffusion process where desalination takes places in the form of
water vapor transport across the membrane. It has low second law efficiency due to parasitic heat
losses. The objective of the first part of the investigation is to thoroughly analyze a Direct
Contact Membrane Distillation (DCMD) system from the view point of yield and exergy. The
insights from exergy analysis are used in a design study, which is used for performance
optimization. The first part concludes with a design procedure and design windows for large scale
DCMD construction.
In the second part of the investigation, focus is moved to waveguide solar energy
collector. The idea behind an ideal waveguide is to reduce the complexity of modeling solar
energy collection. The mathematical model provided in this analysis can be extended to a
family of non-imaging optics in solar energy and serves as a benchmarking analysis tool. A
waveguide is suitable for low temperature operations due to limitations on maximum continuous
temperature of operation. Thus, it becomes an ideal solution for DCMD applications. A levelized
cost analysis is presented for a waveguide powered DCMD plant of a 30,000 capacity. A
combination of waveguide and DCMD shows levelized cost of water at $1.80/m3, which is found
to be lower than previously reported solar desalination water costs.Master of Science
34
Floge, Sheri Ann. "Seasonal Variations in Colloidal Chromophoric Dissolved Organic Matter (CDOM) in the Damariscotta River Estuary, Maine". Fogler Library, University of Maine, 2005. http://www.library.umaine.edu/theses/pdf/FlogeSA2005.pdf.
Testo completo
35
Tuit, Caroline Beth 1973. "The marine biogeochemistry of molybdenum". Thesis, Massachusetts Institute of Technology, 2003. http://hdl.handle.net/1721.1/58369.
Testo completoAbstract (sommario):
Thesis (Ph. D.)--Joint Program in Marine Geology and Geophysics (Massachusetts Institute of Technology, Dept. of Earth, Atmospheric and Planetary Sciences, and the Woods Hole Oceanographic Institution), 2003.Includes bibliographical references.
Prevailing wisdom holds that the vertical distribution of molybdenum (Mo) in the open ocean is conservative, despite Mo's important biological role and association with Mn oxides and anoxic sediments. Mo is used in both nitrogenase, the enzyme responsible for N2 fixation, and nitrate reductase, which catalyzes assimilatory and dissimilatory nitrate reduction. Laboratory culture work on two N2 fixing marine cyanobacteria, Trichodesmium and Crocosphaera, and a marine facultative denitrifier, Marinobacter hydrocarbanoclasticus, showed that Mo cell quotas in these organisms were positively correlated with Mo-containing enzyme activity. Mo concentrations in Crocosphaera dropped almost to blank levels when not fixing N2 suggesting daily synthesis and destruction of the entire nitrogenase enzyme and release of Mo. Trichodesmium cultures, however, retained a pool of cellular Mo even when not fixing N2. Colonies of Trichodesmium collected in the field have Mo:C tenfold higher than seen in culture, these Mo:C ratios were reflected in SPM samples from the same region. Fe:C ratios for Trichodesmium were between 12-160 pmol:mol in field and culured samples. The Fe:C ratio of Crocosphaera was established to be 15.8 =/+ 11.3 under N2 fixing conditions. Mo cellular concentrations in cultured organisms were too small to significantly influence dissolved Mo distributions, but may slightly affect Suspended Particulate Matter (SPM) distributions. Mean SPM Mo:C ratios were slightly elevated in regions of N2 fixation and denitrification.. A high precision (=/+ 0.5%) isotope dilution ICP-MS method for measuring Mo was developed to re-evaluate the marine distribution of Mo in the dissolved and particulate phase.
(cont.) Mn oxides were not found to significantly influence either the dissolved or SPM Mo distribution. Dissolved Mo profiles from the Sargasso and Arabian Sea were conservative. However, dissolved Mo profiles from the Eastern Tropical Pacific showed both depletion and enrichment of dissolved Mo possibly associated with interaction of Mo with coastal sediments. Dissolved Mo profiles in several California Borderland Basins showed 1-2 nM Mo depletions below sill depth. A more focused study of water column response to sediment fluxes using the high precision Mo analyses is necessary to determine whether these phenomena are related.
by Caroline Beth Tuit.
Ph.D.
36
Burnett, Danielle Lee. "Determining the relative influence of mental pollutants in Newport and Laguna beach seawater on the Giant Kelp (Macrocystis pyrifera) populations of Crystal Cove State Park by analysis of sieve sap metals". Thesis, California State University, Long Beach, 2014. http://pqdtopen.proquest.com/#viewpdf?dispub=1527307.
Testo completo
37
FIGUEIRA, RUBENS C. L. "Inventario de radionuclideos artificiais em agua do mar e sedimentos da costa sul do Brasil". reponame:Repositório Institucional do IPEN, 2000. http://repositorio.ipen.br:8080/xmlui/handle/123456789/10817.
Testo completoAbstract (sommario):
Made available in DSpace on 2014-10-09T12:44:19Z (GMT). No. of bitstreams: 0Made available in DSpace on 2014-10-09T13:57:12Z (GMT). No. of bitstreams: 1 06901.pdf: 9310315 bytes, checksum: 34ec97737bf373b58a295f330b6aa935 (MD5)
Tese (Doutoramento)
IPEN/T
Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
38
Hashim, Ahmed. "Foulants investigations and performance modelling analyses in seawater reverse osmosis (SWRO) desalination". Thesis, University of Newcastle Upon Tyne, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.489274.
Testo completoAbstract (sommario):
The research was mainly concerned with performance analysis in seawater reverse osmosis desalination at the Addur SWRO Desalination Plant, Kingdom of Bahrain; there were four main objectives associated with the research. The first objective was conducting a process performance analysis of the conventional pre-treatment system at the Addur Plant so as to determine its filtration efficiency (Chapter 4). The analysis involved assessment of principal filtration parameters like temperature, silt density index (SDI) and turbidity for one seasonal year (with reference to total organic carbon (TOC), ultra violet absorbance (UVA), humic acids substances (HAS) and total suspended solids (TSS) that reflect the fouling potential of organic matter in the seawater feed). Through the evaluation of these parameters' time varying profile trends, specific key aspects were acknowledged. It was established that the incoming seawater quality is characterised as complex and most difficult seawater feed utilised for seawater RO desalination and confirmed that the , pre-treatment was unable to meeting its design performance parameters (i.e. reduce the raw seawater SDI to 2.7 and remove organic matter). Seeping of various undesirable matter through the pre-treatment was verified through EDX analysis suggesting filtration channelling. A system shortfall in the pre-treatment process was conclusive. It was a~so recognised from the profile trends that SDI and turbidity were influenced by seawater . temperature, as micro-organisms flourish within high temperature regions. The second objective was carrying out comprehensive performance analyses on three leading RO membrane modules in seawater desalination tested at similar seasonal conditions and seawater feed composition (Chapter 5) through which the most suitable module that withstood the harsh operation conditions was selected to replace the existing membrane modules at the Addur Plant (where the design aspects and operating guidelines for the three modules were also reviewed in Chapter 3). The results demonstrated that Toyobo CTA HF was best suitable and FilmTec spiral wound PA composite proven second suitable while the performance operation and endurance of DuPont HFF PA was not acceptable. both did not exactly correlate to one another owing to the unavailability of the salt concentration in the vicinity of the membrane wall during the actual RO process. In the second model variations in water and salt transport within a seawater RO module during RO were established in terms of flow, pressure and seawater feed concentration traversing through the module. Fundamental parameters to seawater RO processes were determined such as pure water permeability constant (A), mole fraction of concentrated boundary solution (XA2), solute transport parameter ((DAwKO)sw), mass transfer coefficient for seawater on the high pressure side of the membrane (ks»1, concentration polarisation modulus (M) and thickness of concentrated boundary solution (I). All these quantities are unique and not before determined for real seawater RO systems. The third modelling analysis was concerned with developing a mathematical model defining spatial variations in key parameters ofthe seawater feed entering and traversing through the RO module; this was performed in terms of seawater feed temperature,. volumetric permeate flow rate (and related velocity) and the volumetric flow rate, pressure and concentration of solutions on the high pressure side of the membrane during RO separation. The results achieved through this research have been of primary significance to the development of the pre-treatment and seawater RO process operations and systems at the Addur SWRO Desalination Plant while the consequences of the solutio.ns recommended henceforth had reshaped the configuration of the plant, enhanced production and ensured availability and reliability.
39
Carvalho, Maria Leonor. "Corrosion of copper alloys in natural seawater : effects of hydrodynamics and pH". Thesis, Paris 6, 2014. http://www.theses.fr/2014PA066304/document.
Testo completoAbstract (sommario):
Cette thèse, réalisée en étroite collaboration avec le partenaire industriel RSE S.p.A (Italie), s’inscrit dans le cadre du projet européen BIOCOR ITN. Les alliages de cuivre habituellement utilisés dans les circuits de refroidissement de centrales électriques peuvent être affectés par la biocorrosion induite par la formation d’un biofilm. L’objectif de ce travail était d’étudier the comportement à la corrosion de l’alliage 70Cu-30Ni et d’un laiton contenant 2% d’aluminium en milieu marin, dans des conditions industrielles réelles (expériences sur le terrain) et en laboratoire. L’influence de différents paramètres, tels que la solution (eau de mer naturelle filtrée (FNSW) vs eau de mer artificielle (ASW)), la concentration en biomolécules (biomolécules naturellement présentes dans l’eau de mer vs une protéine modèle, l’albumine de sérum bovin (BSA)), l’hydrodynamique (conditions statiques, sous circulation et agitation, électrode à anneau tournant) et le pH (8,0 ; 6,0 et 3,7), a été évaluée. Sur le terrain, le comportement global à la corrosion et les traitements antifouling ont été suivis en utilisant des techniques électrochimiques (potentiel de corrosion Ecorr vs temps, LPR), gravimétriques (pertes de masse) et génétiques. En laboratoire, des mesures électrochimiques (Ecorr vs temps, courbes de polarisation, spectroscopie d’impédance électrochimique), réalisées pendant les toutes premières étapes de formation des couches d’oxydes (1 h d’immersion), ont été combinées à des analyses de surface par XPS et ToF-SIMS. A partir des expériences sur le terrain, l’analyse microbiologique et moléculaire des biofilms formés sur les deux alliages de cuivre dans l’eau de mer naturelle montre la présence des espèces bactériennes Marinobacter, Alteromonas et Pseudomonas. In the case of Al brass, the single experimental loop illustrates both anodic charge transfer and anodic mass transport. A partir des expériences en laboratoire, des modèles sont proposés pour analyser les données d’impédance obtenues à Ecorr. Dans le cas de 70Cu-30Ni, la boucle HF illustre principalement le transfert de charge anodique (diamètre égal à Rta) ; alors que la boucle BF est liée au transport de matière anodique et au blocage partiel de la surface par CuCl. Dans le cas du laiton, la seule boucle expérimentale illustre à la fois le transfert de charge anodique et le transport de matière anodique. Le comportement électrochimique et la composition chimique de surface de l’alliage 70Cu-30Ni sont similaires dans ASW et dans FNSW statiques, du fait de la faible concentration en biomolécules dans FNSW. En comparaison de l’alliage 70Cu-30Ni dans ASW statique sans biomolécules, pour lequel une couche duplex épaisse (couche externe de Cu2O redéposé et couche interne de nickel oxydé) est montrée, la présence de BSA conduit à une couche mixte d’oxydes de Cu et de Ni d’épaisseur plus faible ; les résultats montrent aussi un ralentissement de la réaction anodique et un faible effet d’inhibition de la corrosion en présence de BSA. Sous circulation et agitation, une couche mixte d’oxydes de Cu et de Ni, de très faible épaisseur, est obtenue. Pour les deux alliages dans FNSW, le courant de corrosion icorr estimé à partir de Rta est indépendant de la vitesse de rotation de l’électrode tournante, du fait de la compensation des effets du potentiel et du transport de matière. Pour 70Cu-30Ni dans FNSW statique, la réaction anodique est ralentie à pH acide (effet cinétique). Pour le laiton, un effet d’inhibition de la corrosion est montré à pH acide, et plus le pH est acide, plus la réaction anodique est lente. Pour 70Cu-30Ni, l’épaisseur de la couche d'oxyde augmente avec la diminution du pH, dans le cas du laiton il est indépendante du pH. La composition chimique de la couche d'oxyde semble avoir un effet sur la quantité de protéines adsorbées et l'épaisseur équivalente calculée de la couche organique est très faible (quelques Å pour 70Cu-30Ni et 1 Å pour laiton)This thesis was carried out in the frame of the BIOCOR ITN European project, in close collaboration with the industrial partner RSE S.p.A. (Italy). Copper alloys commonly used in cooling systems of power plants may be affected by biocorrosion induced by biofilm formation. The main objective of this work was to study the corrosion behavior of 70Cu-30Ni alloy and aluminum brass in seawater environments, under real industrial conditions (field experiments) and in laboratory. The influence of different parameters, such as the solution (filtered natural seawater (FNSW) vs artificial seawater (ASW)), the concentration of biomolecules (biomolecules naturally present in seawater vs a model protein, the bovine serum albumin (BSA)), hydrodynamics (static conditions, under flow and stirring, rotating ring electrode (RRE)) and pH (8.0, 6.0 and 3.7), was evaluated. In field, the overall corrosion behavior and antifouling treatments were monitored using electrochemical (corrosion potential Ecorr vs time, LPR), gravimetric (weight losses) and genetic techniques. In lab, electrochemical measurements (Ecorr vs time, polarization curves, EIS), performed during the very first steps of oxide layers formation (1 h immersion time), were combined to surface analysis by XPS and ToF-SIMS. From field experiments, microbiological and molecular analysis of biofilms formed on both copper alloys in natural seawater indicates the presence of Marinobacter, Alteromonas and Pseudomonas bacterial species. From lab experiments, models are proposed to analyze impedance data obtained at Ecorr. In the case of 70Cu-30Ni, the HF loop illustrates mainly the anodic charge transfer (diameter equal to Rta); whereas the LF loop is related to the anodic mass transport and partial blocking effect by CuCl. In the case of Al brass, the single experimental loop illustrates both anodic charge transfer and anodic mass transport. Similar electrochemical behavior and surface chemical composition of 70Cu-30Ni alloy are obtained in static ASW and FNSW, due to the low biomolecule concentration in FNSW. Compared to 70Cu-30Ni in static ASW without biomolecules, for which a thick duplex oxide layer (outer redeposited Cu2O layer and inner oxidized nickel layer) is shown, the presence of BSA leads to a mixed Cu and Ni oxide layer with a lower thickness; the results also show a slow-down of the anodic reaction and a small corrosion inhibition effect in the presence of BSA. Under flow and stirring, a very thin mixed Cu and Ni oxide layer is obtained. For both alloys in FNSW, the corrosion current icorr estimated from Rta is independent of the rotation speed of the RRE, due to compensated potential and mass transport effects. For 70Cu-30Ni in static FNSW, the anodic reaction is slown down at acidic pH (kinetic effect). For Al brass, there is a corrosion inhibition effect at acidic pH, and the more acidic the pH, the slower the anodic reaction. In the case of 70Cu-30Ni alloy, the oxide layer thickness increases with decreasing pH, whereas for Al brass it is independent of the pH. The chemical composition of the oxide layer seems to have an effect on the amount of adsorbed proteins and the calculated organic layer equivalent thickness is very low (few Å for 70Cu-30Ni and 1 Å for Al brass)
40
Bellil, Ali. "Mise au point et modélisation d'un capteur à fibre optique pour le dosage par fluorescence de l'oxygène en milieu marin". Vandoeuvre-les-Nancy, INPL, 1994. http://www.theses.fr/1994INPL090N.
Testo completoAbstract (sommario):
Le sujet que nous avons abordé concerne la mesure de la concentration d'oxygène dissous dans l'eau de mer artificielle en utilisant une sonde moléculaire fluorescente maintenue in-situ par fibres optiques. La durée de vie de la sonde est affectée par la concentration de l'espèce (l'inhibiteur) qu'on veut doser, dans le cas présent: l'oxygène. La sonde moléculaire choisie est l'acide pyrènebutyrique dont la fluorescence se situe dans le bleu. Ce réactif présente une bonne sensibilité à la présence d'oxygène en faible concentration. La concentration de l'oxygène est classiquement obtenue à partir de l'équation cinétique de Stern-Volmer. Théoriquement, la constante de Stern-Volmer (Ksv) dépend des paramètres physico-chimiques du milieu, par exemple: température, viscosité, pH, polarité, la détermination préalable de Ksv dans différentes conditions intéressant l'eau de mer (température, pH) doit donc permettre de déterminer la concentration de l'oxygène via la mesure de la durée de vie. Une autre technique de mesure de durée de vie par ouverture de porte temporelle à ensuite été utilisée dans le but de réaliser une maquette de laboratoire simple d'utilisation. Les problèmes liés au greffage chimique de la sonde à la surface de la fibre ont empêché de mener cette phase à son terme. Des essais encourageants de fixation de la sonde dans un polymère perméable à l'oxygène ont alors été entrepris
41
Sørensen, Lisbet. "Parameters Governing the Adsorption of Crude and Bunker Fuel Oils to Seawater Suspended Particulate Matter". Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for kjemi, 2012. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-16800.
Testo completoAbstract (sommario):
In this study, parameters influencing the adsorption of dispersed oil droplets to suspended particulate matter (SPM) in seawater were investigated. The interaction between oil and SPMs can alter the ultimate fate of oil spilled in marine environments, and it is therefore of interest to be able to predict the effect of these interactions. The chosen parameters of this study were sediment type (carbonate sand, quartz sand and clay) and concentration (5-80 g/L seawater), temperature (5-20 °C) and oil type (two crudes, one condensate and a heavy fuel oil). Special attention was given to the effect of adding chemical dispersant to the oil prior to mixing with water and SPMs.The experimental outline included the mechanical generation of oil droplets using an oil droplet generator. Water with oil droplets were added to a beaker with sediment and a suspension was induced by stirring. After settling and filtration, both the water samples and the sediment samples were subject to extraction, clean-up and analysis by GC-FID. A selection of samples was also analysed by GC-MS.The study shows that oil droplets adsorb as a bulk to SPM. An absence of water-soluble oil components adsorbed to the sediment was observed. Oil type, sediment size and the use of chemical dispersant stand out as most influencing on the adsorption properties of oil droplets to SPM in seawater. The effect of varying temperature was not considerable compared to the other parameters in this study. Partitioning of oil components to the water column was also monitored in this study, and found not to be influenced significantly by any of the studied parameters.
42
Bourhane, Anli. "Méthodes d'investigation de l'intrusion marine dans les aquifères volcaniques (La Réunion et La Grande Comore)". Thesis, La Réunion, 2014. http://www.theses.fr/2014LARE0028/document.
Testo completoAbstract (sommario):
En contexte insulaire volcanique, les aquifères du domaine côtier présentent de très fortes hétérogénéités liées à leur structure, à la disparité de leurs recharges et à l'influence des conditions en aval. Les travaux envisagés ici consistent à élaborer une méthodologie adaptée à différentes configurations hydrogéologiques dans l'optique de mieux imager et comprendre l'évolution du biseau salé. L'acquisition des données est effectuée sur différents sites présentant des configurations hydrogéologiques variées sur le plan de la recharge, de la structure de l'aquifère et de la géomorphologie de la limite en aval. Un réseau d'observation est mis en place sur la côte ouest de l'île de La Réunion, dans la zone littorale allant de L'Ermitage à Saint-Leu. Cette zone est particulièrement intéressante dans le sens où elle présente les types de limites en aval les plus communes aux îles volcaniques à savoir, des côtes rocheuses, des plaines d'arrière-récif et des plaines d'accumulation fluviomarine. Sur La Réunion et la Grande Comore, le milieu volcanique est investigué au moyen de méthodes géophysiques et par une analyse de séries temporelles hydrogéologiques. Les outils géophysiques employés confirment la présence d’un milieu souterrain hétérogène, avec la présence sporadique de chenaux d'écoulement souterrain préférentiel susceptibles de contrôler la dynamique des intrusions marines. Les simulations numériques effectuées par la suite corroborent ces observations. L'analyse des signaux enregistrés indique une forte influence des forçages hydro-climatiques externes sur les nappes côtières. Elle permet aussi de distinguer deux familles de comportement selon le contexte géologique des ouvrages instrumentés. Les résultats de ces travaux mettent en avant une méthodologie de gestion des nappes côtières adaptée au milieu volcanique. Ils contribuent également à l'orientation des programmes de prospection de la ressource en eau souterraine dans ces contextes très complexesIn volcanic islands context, the aquifers of coastal areas have very strong heterogeneities related to their structure, the disparity of their recharge and the influence of the downstream boundaries (rocky coasts, detritic cones...). The works considered here consist to develop a methodology adapted to different hydrogeological configurations in the aim to better understanding the development of saltwater intrusions. Time series recording and geophysical investigations are carried out on various sites, with different hydrogeological conditions, on the west coast of Reunion Island and throughout Grande Comore Island. The groundwater observatory tested in the pilot study area of Reunion was exported to three others experimental sites situated in Grande Comore Island (Indian Ocean). The geophysical investigations reveal a very important lateral heterogeneity along the shoreline due to the existence of 3D volcanic structures such as palaeovalleys filled by recent lava flows. In coastal areas, these structures exert an important role towards the marine intrusion dynamics, like it was confirmed by numerical simulations. Time series recording has allowed the hydrodynamic characterisation of the coastal groundwater and has enhanced the understanding of low and high frequency variations of the groundwater resources quality
43
Palmer, Sara Jane. "Stability of hydrotalcites formed from Bayer refinery environmental control processes". Thesis, Queensland University of Technology, 2010. https://eprints.qut.edu.au/48672/1/Sara_Palmer_Thesis.pdf.
Testo completoAbstract (sommario):
Bauxite refinery residues (red mud) are derived from the Bayer process by the digestion of crushed bauxite in concentrated sodium hydroxide at elevated temperatures and pressures. This slurry residue, if untreated, is unsuitable for discharge directly into the environment and is usually stored in tailing dams. The liquid portion has the potential for discharge, but requires pre-treatment before this can occur. The seawater neutralisation treatment facilitates a significant reduction in pH and dissolved metal concentrations, through the precipitation of hydrotalcite-like compounds and some other Mg, Ca, and Al hydroxide and carbonate minerals. The hydrotalcite-like compounds, precipitated during seawater neutralisation, also remove a range of transition metals, oxy-anions and other anionic species through a combination of intercalation and adsorption reactions: smaller anions are intercalated into the hydrotalcite matrix, while larger molecules are adsorbed on the particle surfaces. A phenomenon known as ‘reversion’ can occur if the seawater neutralisation process is not properly controlled. Reversion causes an increase in the pH and dissolved impurity levels of the neutralised effluent, rendering it unsuitable for discharge. It is believed that slow dissolution of components of the red mud residue and compounds formed during the neutralisation process are responsible for reversion.
This investigation looked at characterising natural hydrotalcite (Mg6Al2(OH)16(CO3)∙4H2O) and ‘Bayer’ hydrotalcite (synthesised using the seawater neutralisation process) using a variety of techniques including X-ray diffraction, infrared and Raman spectroscopy, and thermogravimetric analysis. This investigation showed that Bayer hydrotalcite is comprised of a mixture of 3:1 and 4:1 hydrotalcite structures and exhibited similar chemical characteristic to the 4:1 synthetic hydrotalcite. Hydrotalcite formed from the seawater neutralisation of Bauxite refinery residues has been found not to cause reversion. Other components in red mud were investigated to determine the cause of reversion and this investigation found three components that contributed to reversion: 1) tricalcium aluminate, 2) hydrocalumite and 3) calcium hydroxide. Increasing the amount of magnesium in the neutralisation process has been found to be successful in reducing reversion.
44
Sicre, Marie-Alexandrine. "Echanges de matiere organique a l'interface air-mer". Paris 6, 1987. http://www.theses.fr/1987PA066212.
Testo completoAbstract (sommario):
Etude realisee dans le bassin occidental de le mediterranee fortement soumis aux apports d'origine naturelle ou anthropique du fait de la proximite des sources d'emission. Choix d'une approche par marqueurs lipidiques. Analyse des hydrocarbures et acides gras qui fournissent des informations concernant des phenomenes se deroulant a des echelles differentes. Les flux relatifs aux differents mecanismes ont ete calcules et discutes
45
Guha, Swagata. "Variable-Density Flow Models of Saltwater Intrusion in Coastal Landforms in Response to Climate Change Induced Sea Level Rise and a Chapter on Time-Frequency Analysis of Ground Penetrating Radar Signals". Scholar Commons, 2010. http://scholarcommons.usf.edu/etd/3490.
Testo completoAbstract (sommario):
Populations residing on and near the world’s coasts have become increasingly dependent on coastal groundwater for their supply of freshwater. Under the conditions of predicted climate changes, the expected rise in global sea level can adversely affect the quality and quantity of freshwater resources in coastal areas as a result of saltwater intrusion.
In this study, a suite of two- and three-dimensional variable-density groundwater flow models of major coastal landforms (e.g. deltas, estuaries and small islands) has been constructed to assess the effects of sea level rise (SLR), using different SLR rates of 0.5 m, 1m and 1.5 m over the next 90 years, from 2010-2100. The model results indicate that in natural coastal systems the extent of saltwater intrusion is significantly controlled by the stratigraphy of the depositional environments. Among deltaic aquifers, wave-dominated deltas are more prone to saltwater intrusion than river- and tide-dominated deltas. In case of a partially mixed, microtidal estuary, SLR can cause extensive porewater salinity increases, especially within estuarine sand deposits. Simulations of atoll and barrier islands reveal that carbonate atoll islands with high conductivity units, are severely affected by SLR, resulting in significant reduction of the volume of freshwater lens. In contrast, migrating sandy barrier islands could retain their freshwater resources with rising sea level under conditions of increased recharge, assuming the barriers can migrate in response to SLR. The freshwater lens of barrier island aquifers would reduce in size due to increased evapotranspiration caused by change in vegetation pattern.
When examined for anthropogenic impacts of groundwater withdrawal through pumping, all the coastal aquifers show evidence of saltwater intrusion, with varying degrees of impact. Wave-dominated deltas are more affected by groundwater withdrawal than river- and tide-dominated deltaic aquifers. Saltwater intrusion in atoll islands is further enhanced by pumping withdrawal. It is evident from the results of the simulations that, the potential effects on coastal aquifers of groundwater withdrawals for potable water can easily exceed the adverse effects of SLR in terms of salinity increase.
46
HUANG, BOU CHIN, e 黃博欽. "FINITE ELEMENT ANALYSIS ON SEAWATER INTERCHANGE IN INNER BAY AREA". Thesis, 1996. http://ndltd.ncl.edu.tw/handle/55746661420473972803.
Testo completoAbstract (sommario):
碩士國立中山大學
海洋環境學系
84
8 文主要是探討港灣變形對於港灣之擴散以及自淨能力的影響,以澎湖青 灣為研究對象,以有限元素法加以分析,評估其變形後之港灣自淨能力. THE RESEARCH DESCRIBED IN THIS PAPER INVOLVES THE INFLUENCE OF THE DEFORMATION OF THE BAY ON DIFFUSION AND SELF-CLEANING ABILITY. CHING-WAN IS THE EXAMPLE TO EVALUATE THE SELF-CLEANING ABILITY AFTER DEFORMATION USING THE FINITE ELEMENT METHOD TO SIMULATE.
47
Weeks, Debra A. "Determination of iron and its forms in the coastal ocean using flow injection analysis". Diss., 2002. http://catalog.hathitrust.org/api/volumes/oclc/50734116.html.
Testo completo
48
Ssu-YuChou e 周思妤. "A numerical analysis on seawater intrusion in Penghu and its remediation strategy". Thesis, 2016. http://ndltd.ncl.edu.tw/handle/63425632126063295998.
Testo completoAbstract (sommario):
碩士國立成功大學
水利及海洋工程學系
104
In Penghu, Taiwan, the quantity of rainfall is less than that of evaporation. There is a shortage of surface water, and thus groundwater is the main water resource. However, the amount of pumping has increased with increasing urban development and population growth, and thus seawater intrusion and groundwater salinization have become more serious. Previous studies have used a groundwater numerical model to simulate groundwater salinization. Therefore, we use MODFLOW and its sub-mode MT3DMS to simulate the groundwater level and chloride concentration distribution in Penghu. The chloride concentration is used as a salinization indicator. After calibrating and verifying the model, three scenarios are used to predict the groundwater salinization in this area. The results show that a remediation strategy can raise the groundwater level and dilute the salt concentration in whole area. In addition, the priority area for the injection of freshwater is Gangzih village.
49
ZHEN, KUANG-LONG, e 鄭光龍. "Method of trace metal pre-concentration and analysis in seawater and corals". Thesis, 1988. http://ndltd.ncl.edu.tw/handle/98818904375016772990.
Testo completo
50
Ming-Shi, Wamg, e 王銘熙. "The Analysis and Application of Artifical Recharge Method in Improving Seawater Intrusion". Thesis, 2000. http://ndltd.ncl.edu.tw/handle/62846474132754808019.
Testo completoAbstract (sommario):
碩士中原大學
土木工程學系
88
In Taiwan, The demand for water resource has led to many serious problems and water resource also has not equally distributed. Many places solve the shortage of the water by withdrawing groundwater. As a result, the storage of the groundwater decreases day-by-day, and groundwater table drop off. This kind of situation is especially serious in Ping-tung coastal areas. Now Ping-tung faces land subsidence, seawater intrusion, and soil salinization This study uses a three-dimension groundwater flow model, MODFLOW developed by USGS, to simulate the groundwater state of Ping-tung coastal areas. Then by using another three-dimension transport model, MT3DMS simulate chloride concentration in coastal areas. Based on the result of the simulation, the effectiveness of artificial recharge method in improving seawater intrusion can be evaluated. The results of simulation shows, the zero water-table areas in Ping-tung coastal areas were extensive, and chloride had moved to inland. The problem of seawater intrusion escalated. The study uses artificial recharge wells; recharging groundwater in coastal areas to form continues pressure head. If water can constantly being recharged, the poor condition, can be improved and the land-value will increase.