Dissertations / Theses on the topic 'Water mass'
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1
LI, ZHIWEI. "NETWORK WATER QUALITY MODELING WITH STOCHASTIC WATER DEMANDS AND MASS DISPERSION." University of Cincinnati / OhioLINK, 2006. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1147989825.
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Jullion, Loĭc. "Water mass modification in the southwestern Atlantic." Thesis, University of East Anglia, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.446168.
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LEE, YEONGHO. "MASS DISPERSION IN INTERMITTENT LAMINAR FLOW." University of Cincinnati / OhioLINK, 2004. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1085750678.
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Lindblom, Jenny. "Condensation irrigation : simulations of heat and mass transfer." Licentiate thesis, Luleå : Luleå University of technology, 2006. http://epubl.luth.se/1402-1757/2006/08.
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Brunet, Robert A. H. "Silent discharge water treatment, mass transfer and reaction rates." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp03/MQ39805.pdf.
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Brandon, Mark Alan. "Winter surface water mass modification in the Greenland Sea." Thesis, University of Cambridge, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.388764.
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Zhang, Huai-Min Ph D. Massachusetts Institute of Technology. "Circulations and water mass balances in the Brazil Basin." Thesis, Massachusetts Institute of Technology, 1991. http://hdl.handle.net/1721.1/57934.
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Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences and Woods Hole Oceanographic Institution, 1991.Bibliography: p.151-155.
by Huai-Min Zhang.
M.S.
8
PIVETTA, TOMMASO FERRUCCIO MARIA. "Gravimetry for monitoring water mass movements in karstic areas." Doctoral thesis, Università degli Studi di Trieste, 2021. http://hdl.handle.net/11368/2988158.
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Karst aquifers represent a significant source of water for about 1/4 of the world’s population. The water circulation in karst occurs mostly underground and it is mainly controlled by alternation of small conduits and large voids present in the rock massif. Such intricate void distribution combined with an irregular recharge provided by the rain results in fast and complex water flows with temporary accumulation of huge water volumes in the voids. The knowledge of the dynamics of such system is usually limited to the areas where a direct access to the vadose zone through speleological exploration is possible. Given the importance of such aquifers and their vulnerability it is important to have a detailed picture of the water dynamics and of the underground water paths.
Gravimetry offers a valid complement to classical hydrologic measurements in order to monitor the recharge process.
In this thesis, I show an innovative integration of gravimetric and hydrologic observations to constrain a hydrodynamic model of the Škocjan cave system (Slovenia). The Škocjan caves hydrology is mostly governed by the allogenic contribution of the Reka River, which during flood event causes the accumulation of several millions of m3 of water in the cave system for few hours. In 2018 I installed a continuous recording gravimeter nearby Škocjan which allowed the detection of several gravity transients related to the local hydrologic contribution.
Gravity observations are sensitive to several other contributions apart the hydrology, such as Earth and marine tides, atmospheric mass redistribution, water mass variations in oceans. All these phenomena superpose their effects and should be carefully evaluated and removed before unveiling the local hydrology contribution. Before discussing the hydrologic gravity signals, the thesis illustrates the efforts in modelling and removing all the non-hydrologic related gravity contributions. The study area is close to the Adriatic Sea, hence global models of tidal and non-tidal ocean (NTO) gravity effects could be inadequate for the correction. I prove that while tidal models are sufficiently accurate to remove the marine tidal influence a dedicated correction of the NTO is required. This was fulfilled by modelling the gravity variations due to a 4D mass model of the NTO constrained by tide gauge observations. The gravity residuals, obtained after reducing the observations for all the non-hydrologic effects, revealed anomalies correlated to the Reka flooding; the transients lasted for 12-24 hours with amplitudes in the range 10-450 nm/s2. I focused my analysis on a large flood event in February 2019 that caused water level variations >90 m inside the caves and gravity variations >400 nm/s2. The gravity and the hydrologic data were used to constrain a hydraulic model of the cave system which approximated the cavity through a series of interconnected conduits with rectangular cross-section. I fitted hydrologic and gravity observations obtaining a 4D model of the water mass variations in the cave system; the model revealed that >3 106 m3 of water were temporary accumulated during the peak’s flood. The inclusion of gravity observations improves water mass budget of the caves, which previously were based relying only on hydrological observations.
Finally, the gravity data allowed to draw some general conclusions on the detectability of water storage variations in karst through gravimetry. I assessed the noise level of the Škocjan gravimeter which is about 10 nm/s2 in the diurnal spectral band and which can be taken as representative of the noise level of a typical spring based gravimeter. Relying on realistic water level variations I estimated the expected gravity signals on surface due to temporary water accumulation in other
caves of the Classical Karst. For all the considered caves the gravity signal is above the noise threshold, suggesting that a remote monitoring of the storage variations is feasible.Karst aquifers represent a significant source of water for about 1/4 of the world’s population. The water circulation in karst occurs mostly underground and it is mainly controlled by alternation of small conduits and large voids present in the rock massif. Such intricate void distribution combined with an irregular recharge provided by the rain results in fast and complex water flows with temporary accumulation of huge water volumes in the voids. The knowledge of the dynamics of such system is usually limited to the areas where a direct access to the vadose zone through speleological exploration is possible. Given the importance of such aquifers and their vulnerability it is important to have a detailed picture of the water dynamics and of the underground water paths. Gravimetry offers a valid complement to classical hydrologic measurements in order to monitor the recharge process. In this thesis, I show an innovative integration of gravimetric and hydrologic observations to constrain a hydrodynamic model of the Škocjan cave system (Slovenia). The Škocjan caves hydrology is mostly governed by the allogenic contribution of the Reka River, which during flood event causes the accumulation of several millions of m3 of water in the cave system for few hours. In 2018 I installed a continuous recording gravimeter nearby Škocjan which allowed the detection of several gravity transients related to the local hydrologic contribution. Gravity observations are sensitive to several other contributions apart the hydrology, such as Earth and marine tides, atmospheric mass redistribution, water mass variations in oceans. All these phenomena superpose their effects and should be carefully evaluated and removed before unveiling the local hydrology contribution. Before discussing the hydrologic gravity signals, the thesis illustrates the efforts in modelling and removing all the non-hydrologic related gravity contributions. The study area is close to the Adriatic Sea, hence global models of tidal and non-tidal ocean (NTO) gravity effects could be inadequate for the correction. I prove that while tidal models are sufficiently accurate to remove the marine tidal influence a dedicated correction of the NTO is required. This was fulfilled by modelling the gravity variations due to a 4D mass model of the NTO constrained by tide gauge observations. The gravity residuals, obtained after reducing the observations for all the non-hydrologic effects, revealed anomalies correlated to the Reka flooding; the transients lasted for 12-24 hours with amplitudes in the range 10-450 nm/s2. I focused my analysis on a large flood event in February 2019 that caused water level variations >90 m inside the caves and gravity variations >400 nm/s2. The gravity and the hydrologic data were used to constrain a hydraulic model of the cave system which approximated the cavity through a series of interconnected conduits with rectangular cross-section. I fitted hydrologic and gravity observations obtaining a 4D model of the water mass variations in the cave system; the model revealed that >3 106 m3 of water were temporary accumulated during the peak’s flood. The inclusion of gravity observations improves water mass budget of the caves, which previously were based relying only on hydrological observations. Finally, the gravity data allowed to draw some general conclusions on the detectability of water storage variations in karst through gravimetry. I assessed the noise level of the Škocjan gravimeter which is about 10 nm/s2 in the diurnal spectral band and which can be taken as representative of the noise level of a typical spring based gravimeter. Relying on realistic water level variations I estimated the expected gravity signals on surface due to temporary water accumulation in other caves of the Classical Karst. For all the considered caves the gravity signal is above the noise threshold, suggesting that a remote monitoring of the storage variations is feasible.
9
Glogowski, Silke [Verfasser]. "Water mass dynamics around cold-water coral reefs in the North Atlantic / Silke Glogowski." Kiel : Universitätsbibliothek Kiel, 2017. http://d-nb.info/1141678004/34.
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Padowski, Julie C. "Direct measurement of water and solute mass fluxes using a passive surface water flux meter." [Gainesville, Fla.] : University of Florida, 2005. http://purl.fcla.edu/fcla/etd/UFE0013283.
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Pemberton, Per. "Freshwater processes and water mass transformation in the Arctic Ocean." Doctoral thesis, Stockholms universitet, Meteorologiska institutionen (MISU), 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-107594.
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This thesis explores freshwater-related processes and water mass transformation in the Arctic Ocean. Knowledge of these processes is important from both a local and a global perspective. Globally, because the export of cold and low saline water and sea ice might influence the North Atlantic and global meridional overturning circulation. Locally, because freshwater processes affect the vertical stratification and permit favorable conditions for the ice cover. Models of different complexity are the main tools of the present work. A part of the material considers how these models can be used to examine the key processes governing freshwater balance. Additionally, the freshwater budgets amongst 10 different ocean general circulation models (OGCMs) are compared and robust features and weaknesses identified. A large part considers the freshwater processes governing the stratification with an emphasis on the low saline upper parts. The interactions between freshwater sources and sinks are studied in an OGCM using passive tracers. It is found that the composition, pathways and shelf-basin exchange of low saline water primarily involve processes linked to Siberian runoff, Pacific water and sea-ice melting and formation. Motivated by observed changes and paleorecords the sensitivity of the stratification is further explored in freshwater perturbation experiments with an OGCM. The response yields a deeper halocline for decreasing freshwater input, in line with a theoretical model. The final part focuses on a new framework for analyzing water mass transformations. In the framework volume, heat and salt budgets are computed in salinity-temperature space. Using different OGCMs it is shown how surface and interior processes transform inflowing waters towards colder and fresher waters and how the halocline renewal rate can be estimated. Limiting cases for the water mass transformation balance are identified by separating contributions from surface, internal and boundary fluxes.At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 3: Submitted. Paper 4: Manuscript.
12
Fujio, Shinzo. "Diagnostically Derived World Ocean Circulation and the Water Mass Formation." 京都大学 (Kyoto University), 1992. http://hdl.handle.net/2433/168820.
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本文データは平成22年度国立国会図書館の学位論文(博士)のデジタル化実施により作成された画像ファイルを基にpdf変換したものであるKyoto University (京都大学)
0048
新制・課程博士
博士(理学)
甲第4974号
理博第1371号
新制||理||765(附属図書館)
UT51-92-J21
京都大学大学院理学研究科地球物理学専攻
(主査)教授 今里 哲久, 教授 奥西 一夫, 教授 廣田 勇
学位規則第4条第1項該当
13
Yao, Fengchao. "Water Mass Formation and Circulation in the Persian Gulf and Water Exchange with the Indian Ocean." Scholarly Repository, 2008. http://scholarlyrepository.miami.edu/oa_dissertations/183.
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The Persian Gulf is a shallow, semi-enclosed marginal sea where the Persian Gulf Water (PGW), one of the most saline water masses in the world, is formed due to the arid climate. The PGW flushes out of the Persian Gulf as a deep outflow and induces a surface inflow of the Indian Ocean Surface Water (IOSW), driving an inverse-estuarine type water exchange through the Strait of Hormuz. In this dissertation, the circulation and water mass transformation processes in the Persian Gulf and the water exchange with the Indian Ocean through the Strait of Hormuz, in response to the atmospheric forcing, are studied using the HYbrid Coordinate Ocean Model (HYCOM). The model is driven by surface wind stress, heat and fresh water fluxes derived from two sources: the COADS (Comprehensive Ocean-Atmosphere Data Set) monthly climatology and high frequency (2-hourly) MM5 (The Fifth-Generation NCAR/Penn State Mesoscale Model) output. This study is motivated by the time series measurements in the Strait during December 1996 to March 1998 by Johns et al. (2003), which also serve as a major benchmark for evaluating the model results. The simulations with climatological forcing show that the IOSW propagates in two branches into the Gulf, one along the Iranian coast toward the northern gulf and the other one onto the southern banks driven by the Ekman drift by the prevailing northwesterly winds. These two branches of inflow form two cyclonic gyres in the northern and in the southern gulf respectively. Cold, saline deep waters are formed both in the northern gulf and in the southern gulf during the wintertime cooling period and their exports contribute seasonally to the outflow in the strait. After formation in winter, the dense water in the shallow southwestern gulf spills off into the strait and causes high-salinity pulses in the outflow in the strait, a phenomenon also present in the observations. The export of dense waters from the northern gulf persists throughout the year, with the largest cold water export in summer. The intrusion of the IOSW in the model extends much farther into the Gulf in summer than in winter, which is in agreement with observations. By analyzing the salt balance in the basin and conducting sensitivity experiments, we show that it is the balance between the advection of IOSW and vertical upward flux induced by vertical mixing that mainly controls the seasonal variation of the surface salinity. The surface salinity in winter is increased by upward mixing from saltier subsurface waters, which is caused by the strong vertical mixing condition maintained by the surface heat loss. Surface wind stress, which opposes the inflow and is stronger in winter than in summer, plays a secondary role in modulating the seasonal intrusion of the IOSW. The MM5 high frequency forcing, capable of resolving synoptic weather events, leads to increased heat loss in winter, enhanced vertical mixing and higher annual mean evaporation rate. In the simulation with the high frequency forcing, the waters in the gulf are generally about 3 degree C colder and 1 psu fresher than with COADS forcing, and agree better with observations. The high-frequency forcing has little effect on the export of the dense waters from the northern gulf but delays the spillage of the waters from the southern gulf to April. A notable synoptic feature of the simulations is the annual appearance of eddies along the intruding salinity front. The typical sizes of the fully developed eddies in summer are about 100 km, about 3 times of the local Rossby deformation radius, consistent with a baroclinic instability process. The existence of these eddies is confirmed in satellite images of surface temperature in the Gulf.
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Huang, Lingyan. "Mass transport due to surface waves in a water-mud system." Click to view the E-thesis via HKUTO, 2005. http://sunzi.lib.hku.hk/hkuto/record/B35380457.
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Shawesh, Abdussalam Mohamed. "A study of heat and mass transfer in Dual Water Heaters /." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape11/PQDD_0002/MQ44040.pdf.
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Huang, Lingyan, and 黃凌燕. "Mass transport due to surface waves in a water-mud system." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2005. http://hub.hku.hk/bib/B35380457.
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Zhou, Shuzhen. "Compact photocatalytic reactors for water treatment : mass and photon transfer issues." Thesis, Lyon 1, 2014. http://www.theses.fr/2014LYO10331.
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Le but de ce travail est de concevoir, opérer et caractériser un réacteur photo-catalytique compact qui opère en régime non limité par le transfert de matière et le transfert de la lumière. Plus particulièrement, il s'agit de traiter de l'eau polluée par un principe pharmaceutique, le diclofénac (DCF) dans un pilote à l'échelle du laboratoire et, essentiellement, de fournir les données quantitatives pour le dimensionnement d'un pilote industriel. La fabrication du dépôt du photocatalyseur TiO2, la désactivation, les transferts interne et externe de matière et l'extinction lumineuse dans la couche de TiO2 ont été étudiés expérimentalement. Les paramètres opératoires – débits, concentration initiale de MB et d'oxygène, intensité lumineuse, épaisseur du dépôt – ont été variés. Un modèle de simulation du réacteur a été construit qui incorpore les transferts externe et interne de matière et l'extinction lumineuse dans le cas d'une molécule modèle, le bleu de méthylène (MB). Enfin, à l'aide d'outils de résolution numérique, les paramètres du modèle ont été déterminées. Cette méthodologie a ensuite été appliquée partiellement à la molécule cible, le DCF, en combinant hydrogénation et photocatalyse. Pour le dépôt de catalyseur (TiO2-P25), la méthode de dépôt par gouttes a été sélectionnée car conduisant à une large gamme d'épaisseurs. La densité du catalyseur déposé a été déterminée ce qui a permis de mettre au point une méthode d'évaluation rapide de l'épaisseur du film par simple pesée. Le coefficient d'extinction du rayonnement UV utilisé dans ce travail à travers le film de TiO2 a été déterminé et comparé favorablement avec les données de la bibliographie. Le composé DCF a été dégradé par hydrogénation et par oxydation photocatalytique. L'hydrogénation se révèle être une méthode de choix pour l hydrodéchloration et l'hydrodéaromatisation du DCF dans l'eau en présence d'un catalyseur au ruthénium déposé sur charbon actif (5%Ru, 59.7% H2O, type H 101B Degussa) à 60°C et 25 bars. Les résultats de cette recherche peuvent potentiellement s'appliquer à d'autres secteurs industriels où des systèmes compacts sont nécessairesIn this work, we aim to overcome photon transfer limitations and mass transfer limitations to design, operate and characterize a compact photocatalytic reactor to remove the pharmaceutical pollutant diclofenac (DCF) in a laboratory pilot reactor, and further to produce metrics for the design of a full scale industrial pilot. Metrics include rate law for pollutant degradation, optimal photocatalytic film thickness, catalyst deactivation law, light distribution, geometry, etc. under process conditions. Catalyst deposition, kinetics, catalyst deactivation; external and internal mass transfer and UV light diffusion in TiO2 film, etc. were studied with a model molecule methylene blue (MB) and operation parameters - flow rate, initial concentration of MB, light intensity, thickness of catalyst film, dissolved oxygen, etc - on MB photocatalytic degradation were investigated. A reactor model was built considering the mass transfer and light extinction issues. Numerical integration was performed to fit the experimental data to determine the intrinsic rate constant and order of light intensity. This methodology was then applied albeit partially to the targeted DCF, combined photocatalysis together with hydrogenation technology. Drop-coating method was chosen mainly for catalyst deposition and a wide range of catalyst (TiO2 P25) film was got with this method. A method to get and use the density of the catalyst film was performed to determine the thickness of deposited catalyst film. The extinction coefficients of the Pyrex glass and TiO2-P25 film were measured experimentally and compatible with literature data. DCF was degraded by photocatalysis and hydrogenation. Hydrogenation was proved to be effective for hydrodechlorination and hydrodearomatisation of DCF in water in the presence of Ru/C catalyst (5% Ru, Type H 101B Degussa) at 60°C and around 25 bars. This research can also be applied to other industrial sectors (off-shore platforms, “inside-thecity” production units, etc.) where such compact process may be required
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Mölder, Erik. "Measurement of the oxygen mass transfer through the air-water interface /." Tartu: Tartu University Press, 2005. http://dspace.utlib.ee/dspace/bitstream/10062/616/5/molder.pdf.
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FASANO, MATTEO. "Heat and mass transfer of water at nanoscale solid-liquid interfaces." Doctoral thesis, Politecnico di Torino, 2015. http://hdl.handle.net/11583/2615703.
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A better physical understanding of heat and mass transfer of water at nanoscale solid interfaces is essential for the rational design of novel nanoconstructs for clean water and energy as well as for biomedical applications. Both nanoscale transfer phenomena are strongly influenced by solid-liquid nonbonded interactions occurring at the interface.
First, classical Molecular Dynamics (MD) is used for investigating water transport in the proximity of several inorganic and biological solid surfaces, according to different surface functionalizations (i.e. hydrophobic/hydrophilic) and physical conditions. Results show that the self-diffusion coefficient D of water in nanoconfined geometries is reduced respect to bulk conditions. In fact, D scales with the dimensionless parameter θ, i.e. the ratio between the volume of confined water, which is defined by the solvent accessible surface and a characteristic length of confinement δ depending on surface chemistry, and the total one. The D(θ) relationship is then interpreted within the thermodynamics of supercooled water.
Second, water diffusion in nanoconstructs also plays a fundamental role in nanoscale heat transfer phenomena. Non-equilibrium MD simulations are used to investigate the characteristic solid-liquid thermal boundary resistance of solvated nanoparticles with different degree of hydrophobicity, curvature or surface pegylation, where modeling guidelines are needed in order to optimize the design of nanofluids for novel coolants, solar collectors or ablation therapies. Results show that solid-liquid thermal boundary transmittance is proportional to the hydrophilicity of the nanoparticle surface.
Once a theoretical framework for the transport properties of nanoconfined water is established, the obtained scaling laws are applied to engineering and biomedical applications.
Atomistic simulations are used for investigating the critical limitations of zeolite-based materials for filtering or thermal storage purposes, namely the limited water flux within the subnanometer pores and the low thermal transmittance, respectively. Infiltration isotherms of water in defective silicalite-I membranes are evaluated by MD simulations, and the water transport within the nanopores is interpreted in terms of solvent-structure and solvent-solvent nonbonded interaction energies. Large networks of carbon nanofillers, instead, may be introduced for enhancing the thermal transmittance of zeolite-based composite materials: non-equilibrium MD simulations show that CNTs with short overlap length and a few bonded interlinks already present a remarkable enhancement in the overall transmittance of the nanoconstructs, which also prove the importance of solid-solid interfaces for optimizing heat transfer at the nanoscale.
Finally, water self-diffusivity has also a strong influence on the performances of contrast agents for Magnetic Resonance Imaging (MRI). In fact, lower mobility of water molecules close to MRI contrast agents enhances their longitudinal and transverse relaxivities. Here, MD simulations and the D(θ) relationship are shown to accurately predict the relaxometric responses of Gd(DOTA) or SPIOn MRI contrast agents confined within hydrated nanopores, proving that the D(θ) scaling law can help in tailoring nanostructures with precise modulation of water mobility.
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Sarpola, A. (Arja). "The hydrolysis of aluminium, a mass spectrometric study." Doctoral thesis, University of Oulu, 2007. http://urn.fi/urn:isbn:9789514285578.
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Abstract
This thesis is focused on the hydrolysis of aluminium, the polymerisation of the hydrolysis products, and how these can be monitored by mass spectrometric methods. The main aim of this research is to figure out how the aqueous speciation of aluminium changes as a function of pH (3.2–10), concentration (1–100 mM), reaction time (1s–14d), and counter anion (Cl-, SO42-, HCOO-). The method used was electrospray mass spectrometry. The results showed more variable speciation than those suggested earlier. The main species were Al2, Al3, and Al13, which were found in all of the conditions under scrutiny. The effect of pH was the most remarkable of all the parameters researched. The formation of large highly charged complexes was strongly dependent on it. Also the Al-concentration in the bulk solution had a clear effect on speciation: in dilute solutions there were more protonated ligands and less attached counter anions. This could mean that the species in more diluted bulk solutions had fewer different states of charge. Reaction time caused only minor changes to speciation in the initial pH: there was slightly more variation of a certain sized species in the aged solution. In elevated pH, the birth of important Al13 oligomers was time dependent. The effect of the counter anion was tremendous. In a chloride environment the speciation was rich and diversified. With sulphate the speciation was limited to solid- like compounds, and the variation of single-sized species was almost lacking. The formate as a counter anion caused most surprising results; the charge of aluminium in some studied complexes was lowered from the common 3+ to 1+. If this reaction also occurs in natural circumstances, the uses of aluminium formate would be wide. The results can be utilised in following the progress of dissolution, the mobilization and toxicity of aluminium in natural waters, as well as in water purification, and in reaching minimal chemical contamination levels in sludge as well as in aqueous waste.
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McMahon, Callie Griggs. "Muscle Strength and Body Cell Mass in Postmenopausal Women." Thesis, Virginia Tech, 2001. http://hdl.handle.net/10919/42296.
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It has been observed that the normal process of aging is associated with a decline in muscle strength and mass. It has also been observed that total body potassium and intracellular water (ICW) decrease with age, reflecting a loss of body cell mass (BCM), 60% of which is the skeletal muscle. It is generally accepted that traditional high-intensity strength training (ST) regimens can not only attenuate, but in some cases, reverse some of these aging-related changes. Periodization, a nontraditional approach to strength training, has been demonstrated to stimulate more rapid increases in muscle strength than traditional approaches in young adults; however, it has not been comprehensively evaluated in postmenopausal women. Investigators have consistently reported an increase in muscle strength in older adults undergoing both short- and long-term traditional ST programs. It is fairly well accepted that early increases in muscle strength are attributable to neurologic adaptations. There has been less consistency in the literature regarding the timing and nature of changes in muscle quality and mass with ST. Although several investigators have reported increased muscle protein synthesis rates as early as 2 weeks after ST initiation in older adults, the majority of published reports support the notion that significant NET gains in intracellular protein, and thus, gains in muscle mass/volume/hypertrophy do not occur before 9-10 weeks. Changes in intracellular water, which would be expected to occur with changes in intracellular protein, have not been studied during short-term ST interventions in older adults. Bioimpedance spectroscopy (BIS) has been validated as a field technique to accurately measure ICW (and BCM) changes in HIV infected individuals. The primary aim of the current study was to determine if muscle strength would increase in postmenopausal women undergoing a novel (periodized) ST intervention of 10 weeks duration. A secondary aim was to determine if BIS would detect a change in ICW in the study subjects from baseline to study conclusion.
Study participants were eleven, healthy postmenopausal women between the ages of 60 and 74 (mean age: 65 ± 4.4 y) who had not engaged in ST in the six months preceding the study. ICW and muscle strength were assessed at baseline and at study conclusion. The ST program was conducted twice a week for 10 weeks at the Senior Center in Blacksburg, VA. Participants performed seven different exercises incorporating upper body and lower body muscle groups. The women performed one set of 8-12 repetitions at an intensity of 80% of one repetition maximum (1 RM) the first week, progressing to 2 sets of 8-12 repetitions at the same intensity during the second week. The remaining weeks consisted of three sets of 8-12 repetitions, performed at an intensity of 80%, 75%, and 70% of their current 1 RM, respectively. One RM was reassessed every other week. The major result from this study was that muscle strength of all trained muscle groups increased in postmenopausal women undergoing 10 weeks of pyramid ST (P<0.05). In addition, the pyramid ST protocol utilized in this study was well-tolerated and resulted in no injuries in any of the older women in the study, indicating that this approach may be used safely in this population. Mean ICW measured by the field method BIS did not change over the course of the study. This result was consistent with other published data reporting no changes in lean body mass or muscle volume/area by more sophisticated techniques.Master of Science
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KUBIN, ELISABETH. "Levantine intermediate and deep water formation and water mass characteristics: An Argo float study from 2000 to 2017." Doctoral thesis, Università degli Studi di Trieste, 2020. http://hdl.handle.net/11368/2961199.
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Levantine intermediate water (LIW) is formed in the Levantine Sea (Eastern Mediterranean) and spreads throughout the Mediterranean at intermediate depths, following the general circulation. The LIW, characterized by high salinity and relatively high temperatures, is one of the main contributors of the Mediterranean Overturning Circulation and influences the mechanisms of deep water formation in the Western and Eastern Mediterranean sub-basins. In this study, the LIW and Levantine deep water (LDW) formation processes are investigated using Argo float data from 2001 to 2017 in the Northwestern Levantine Sea (NWLS), the larger area around Rhodes Gyre (RG). To find pronounced events of LIW and LDW formation, more than 800 Argo profiles were analyzed visually. Events of LIW and LDW formation captured by the Argo float data are compared to buoyancy, heat and freshwater fluxes, sea surface height (SSH), and sea surface temperature (SST). All pronounced events (with a mixed layer depth (MLD) deeper than 250 m) of dense water formation were characterized by low surface temperatures and strongly negative SSH. The formation of intermediate water with typical LIW characteristics (potential temperature > 15 °C, salinity > 39 psu) occurred mainly along the Northern coastline, while LDW formation (13.7 °C < potential temperature < 14.5 °C, 38.8 psu < salinity < 38.9 psu) occurred during strong convection events within temporary and strongly depressed mesoscale eddies in the center of RG. This study reveals and confirms the important contribution of boundary currents in ventilating the interior ocean and therefore underlines the need to rethink the drivers and contributors of the thermohaline circulation of the Mediterranean Sea.
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Miller, Stanley David 1960. "Mass separation techniques for the design of fixed film bioreactors." Thesis, The University of Arizona, 1988. http://hdl.handle.net/10150/276846.
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Dissolved organics in wastewater samples were separated into three size fractions (0-1,000 amu, 1,000-10,000 amu, and 10,000 amu-0.22 m) using ultrafiltration (UF) membranes. The mass distribution within each fraction was adjusted by using a new permeation coefficient model to account for membrane rejection. Dissolved organic and soluble BOD (sBOD) removals in a trickling filter were studied for the different size fractions. The Logan trickling filter model was recalibrated and used to generate predicted removals by size fraction of sBOD, dissolved organic carbon (DOC), and biodegradable DOC (bDOC) for a given influent. Although there was moderate agreement between observed and predicted removals, more investigation is needed to explain shifts in material between different size fractions. Of the three parameters, bDOC may offer a better parameter for modelling trickling filter performance than sBOD.
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Lidström, Viktor. "Mass Loading of Space Plasmas." Thesis, Luleå tekniska universitet, Rymdteknik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-62094.
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The solar wind interaction with an icy comet is studied through a model problem. A hybrid simulation is done of a box with evenly distributed water ions and protons, where initially the water ions are stationary, and protons move with the speed of the solar wind. The purpose of the thesis is to investigate the interaction between the two species through the convective electric field, and focus is on early acceleration of pick-up ions, and deflection of the solar wind. It is relevant to the cometary case, because it enables study of the physics of this interaction, without involving other mechanisms, such as bow shock, magnetic field pile-up and draping. The species are found to exchange kinetic energy similar to a damped oscillator, where the dampening is caused by kinetic energy being transferred to the magnetic field. At early times, i.e. times smaller than the gyration time for the water ions, the solar wind does not lose much speed when it is deflected. For comparable number densities, the solar wind can be deflected more than 90° at early times, and loses more speed, and water ions are picked up faster. The total kinetic energy of the system decreases when energy builds up in the magnetic field. The nature of the energy exchange is strongly dependent on the number density ratio between water ions and protons. A density instability with behaviour similar to a plasma beam instability forms as energy in the magnetic field increases, and limits the amount of time the simulation preserves total energy, for the particular hybrid solver used. There is a discussion on the structure of the density instability, and it is compared to cometary simulations.
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Bohra, Lalit Kumar. "Analysis of Binary Fluid Heat and Mass Transfer in Ammonia-Water Absorption." Diss., Georgia Institute of Technology, 2007. http://hdl.handle.net/1853/19780.
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An investigation of binary fluid heat and mass transfer in ammonia-water absorption was conducted. Experiments were conducted on a horizontal-tube falling-film absorber consisting of four columns of six 9.5 mm (3/8 in) nominal OD, 0.292 m (11.5 in) long tubes, installed in an absorption heat pump. Measurements were recorded at both system and local levels within the absorber for a wide range of operating conditions (nominally, desorber solution outlet concentrations of 5 - 40% for three nominal absorber pressures of 150, 345 and 500 kPa, for solution flow rates of 0.019 - 0.034 kg/s.). Local measurements were supplemented by high-speed, high-resolution visualization of the flow over the tube banks. Using the measurements and observations from videos, heat and mass transfer rates, heat and vapor mass transfer coefficients for each test condition were determined at the component and local levels.
For the range of experiments conducted, the overall film heat transfer coefficient varied from 923 to 2857 W/m2-K while the vapor and liquid mass transfer coefficients varied from 0.0026 to 0.25 m/s and from 5.51×10-6 to 3.31×10-5 m/s, respectively. Local measurements and insights from the video frames were used to obtain the contributions of falling-film and droplet modes to the total absorption rates. The local heat transfer coefficients varied from 78 to 6116 W/m2-K, while the local vapor and liquid mass transfer coefficients varied from -0.04 to 2.8 m/s and from -3.59×10-5 (indicating local desorption in some cases) to 8.96×10-5 m/s, respectively. The heat transfer coefficient was found to increase with solution Reynolds number, while the mass transfer coefficient was found to be primarily determined by the vapor and solution properties. Based on the observed trends, correlations were developed to predict heat and mass transfer coefficients valid for the range of experimental conditions tested. These correlations can be used to design horizontal tube falling-film absorbers for ammonia-water absorption systems.
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Buraglio, Nadia. "Accelerator mass spectrometry of 129I and its applications in natural water systems." Doctoral thesis, Uppsala universitet, Institutionen för materialvetenskap, 2000. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-1077.
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During recent decades, huge amount of radioactive waste has been dumped into the earth's surface environments. 129I (T1/2 = 15.6 My) is one of the radioactive products that has been produced through a variety of processes, including atomic weapon testing, reprocessing of nuclear fuel and nuclear accidents. This thesis describes development of the Accelerator Mass Spectrometry (AMS) ultra-sensitive atom counting technique at Uppsala Tandem Laboratory to measure 129I and discusses investigations of its distribution in the hydrosphere (marine and fresh water) and precipitation. The AMS technique provides a method for measuring long-lived radioactive isotopes in small samples, relative to other conventional techniques, and thus opens a new line of research. The optimization of the AMS system at Uppsala included testing a time of flight detector, evaluation of the most appropriate charge-state, reduction of molecular interference and imporvement of the detection limit. Furthermore, development of a chemical procedure for separation of iodine from natural water samples has been accomplished. The second part of the thesis reports investigations of 129I in natural waters and indicates that high concentrations of 129I (3-4 orders of magnitude higher than in the pre-nuclear era) are found in most of the considered natural waters. Inventory calculations and results of measurements suggest that the major sources of radioactive iodine are the two main European nuclear reprocessing facilities at Sellafield (U.K.) and La Hague (France). This information provides estimates of the transit time and vertical mixing of water masses in the central Arctic Ocean. Results from precipitation, lakes and runoff are used to elucidate mechanisms of transport of 129I from the point sources and its pathways in the hydrological environment. This study also shows the need for continuous monitoring of the 129I level in the hydrosphere and of its future variability.
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Weitbrecht, Volker. "Influence of dead-water zones on the dispersive mass transport in rivers." Karlsruhe : Univ.-Verl, 2004. http://deposit.d-nb.de/cgi-bin/dokserv?idn=972080783.
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Braun, Christian [Verfasser]. "Time-resolved photoelectron spectroscopy of mass-selected metal-water clusters / Christian Braun." Konstanz : Bibliothek der Universität Konstanz, 2012. http://d-nb.info/1026847141/34.
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Oliveira, Fernada Adelina Anselmo Soares Rodrigues. "Mass transfer analysis for the leaching of water soluble components from food." Thesis, University of Leeds, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.328196.
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Harris, Carolyn Louise. "Water mass distribution and Polar Front structure in the Southwestern Barents Sea." Thesis, Massachusetts Institute of Technology, 1996. http://hdl.handle.net/1721.1/54421.
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Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, and Woods Hole Oceanographic Institution, 1996.Includes bibliographic references (leaves 63-66). Includes bibliographical references (leaves 63-66).
by Carolyn Louise Harris.
M.S.
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Troccoli, Alberto. "Ocean data assimilation using the temperature-salinity relation and water mass diagnostics." Thesis, University of Edinburgh, 2000. http://hdl.handle.net/1842/14580.
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In this thesis a novel method for assimilating upper ocean temperature profiles with salinity adjustments into numerical ocean models is presented. The approach uses a T-S relation more local in space and time than the climatological T-S used in previous studies. The assimilation method also avoids convective instability as the temperature data are introduced. In order to test the method, three sets of experiments are carried out. First, Conductivity-Temperature-Depth measurements in the western tropical Pacific, and also instantaneous fields from an ocean model, are used to test the assimilation method by combining one profile with another. These tests recover the salinity profiles and the 0-500-m dynamic height very well (differences smaller than 1 dyn cm). By contrast, analyses using a climatological T-S relation did not provide a good salinity profile or dynamic height (greater than 3 dyn cm errors). Second, a synthetic assimilation experiment using a 3-D primitive equation model is carried out. Four runs are considered: the truth (Tr), the parallel (Pa) and two assimilation runs, one in which the salinity method is applied (AST) and the other in which salinity is left unmodified during the temperature assimilation (ASZ). The only difference between Pa and Tr is that Pa is forced by a wind stress 15% larger than Tr, so as to simulate a systematic observational error. AST and ASZ use the same forcings as Pa. Vertical temperature profiles down to a depth of 525 m are taken as synthetic data from Tr and assimilated every 30 days for two years into AST and ASZ. Results show that AST yields better salinity analyses than both Pa and ASZ, which, in terms of rms errors, translate into at least 15% improvement at the end of the 2-year experiment. In addition to assessing the success of the assimilation method (e.g. using T and S rms), a more physical analysis of the model modifications, due to the assimilation, is presented.
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Rich, J. F. "Integrated mass, solute, isotopic and thermal balances of a coastal wetland /." Access via Murdoch University Digital Theses Project, 2004. http://wwwlib.murdoch.edu.au/adt/browse/view/adt-MU20040520.130717.
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Thesis (Ph.D.) --Murdoch University, 2004.Thesis submitted to the Division of Science and Engineering. Includes bibliographical references (leaves R-1 - R-24). Also available via the World Wide Web at.
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Atkinson, Erin C. "Field-testing of a passive surface water flux meter for the direct measurement of water and solute mass fluxes." [Gainesville, Fla.] : University of Florida, 2007. http://purl.fcla.edu/fcla/etd/UFE0021166.
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Keinath, Christopher Mahlo. "Direct-fired heat pump for multi-pass water heating using microchannel heat and mass exchangers." Diss., Georgia Institute of Technology, 2015. http://hdl.handle.net/1853/54330.
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Absorption heat pump water heaters offer improved performance compared to conventional direct-fired water heaters, with the potential for coefficients of performance well in excess of 1. A primary energy usage comparison with electric heat pumps shows that absorption systems can be competitive with current technology. However, the implementation of these systems in the residential and light commercial market has not been practical for several reasons, including a limited knowledgebase on absorption systems for this application and the lack of compact and economically viable heat and mass exchangers. An improved understanding of the coupled heat and mass transfer processes in thermally driven absorption systems to be used as heat pump water heaters was obtained over the course of this study. In addition, microchannel heat and mass exchangers that enable such compact gas-fired heat pump water heaters were developed and tested. Performance at design and off-design conditions over a range of water and ambient temperatures was simulated in detail with a system-level model developed for this purpose. The system-level model was coupled with a water-tank model to investigate several water heating scenarios including a cold start, response to a medium sized draw and response to stand-by losses. Heat and mass exchangers were designed using component-level heat and mass transfer models. The heat and mass exchangers were first installed and evaluated on a breadboard test facility. Insights from these experiments were then used to design and fabricate a monolithic unit integrating several of the microchannel heat and mass exchangers, coupled with a gas-fired desorber heat exchanger to yield a stand-alone water heater prototype. The performance of the prototype was investigated over a range of water and ambient temperatures. A comparison of results was performed to investigate the deviation between model predictions and experimental values. A refined model was developed that more accurately predicted experimental results. Energy-use and cost analyses were performed and showed the potentially significant energy savings of thermally driven heat pump water heaters.
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Mistry, Bhavnita. "Risk, media and drinking water: An analysis of the media's construction of the Walkerton risk event." Thesis, University of Ottawa (Canada), 2007. http://hdl.handle.net/10393/27574.
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The contamination of the local drinking water supplies in Walkerton, Ontario, in May 2000 was a highly publicized public health risk event, where seven people died and 2,300 other individuals became ill.
The analysis of the media construction of the Walkerton risk event reveals how the media uses important elements of risk to construct this event. The analysis shows how trust and blame issues are used to create this community, by constructing messages about how the community dealt with this risk event. The analysis also reveals how the media concentrate on the negative aspects of the risk, such as the health issues, that aid in framing the stories in a negative tone. Moreover, the analysis illustrates the relative importance of this risk issue on the Canadian media's agenda, for the duration of the study period. These factors may influence public perceptions of risk regarding drinking water.
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Moodley, Anand. "Development of a unified mass and heat integration framework for sustainable design an automated approach /." Diss., Pretoria : [s.n.], 2007. http://upetd.up.ac.za/thesis/available/etd-04222008-094925/.
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Zheng, Bingxue. "Quantitative Analysis and Determination of Microcystin in water by Capillary Electrophoresis Mass Spectrometry." FIU Digital Commons, 2014. http://digitalcommons.fiu.edu/etd/1538.
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The presence of harmful algal blooms (HAB) is a growing concern in aquatic environments. Among HAB organisms, cyanobacteria are of special concern because they have been reported worldwide to cause environmental and human health problem through contamination of drinking water. Although several analytical approaches have been applied to monitoring cyanobacteria toxins, conventional methods are costly and time-consuming so that analyses take weeks for field sampling and subsequent lab analysis. Capillary electrophoresis (CE) becomes a particularly suitable analytical separation method that can couple very small samples and rapid separations to a wide range of selective and sensitive detection techniques. This paper demonstrates a method for rapid separation and identification of four microcystin variants commonly found in aquatic environments. CE coupled to UV and electrospray ionization time-of-flight mass spectrometry (ESI-TOF) procedures were developed. All four analytes were separated within 6 minutes. The ESI-TOF experiment provides accurate molecular information, which further identifies analytes.
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Shi, Jianyou. "Conservative and reactive mass transport in homogeneous and heterogeneous ground-water flow systems /." The Ohio State University, 2000. http://rave.ohiolink.edu/etdc/view?acc_num=osu1488194825667624.
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Winters, Tim. "Oxygen isotope ratios in seawater of the North Atlantic." Thesis, University of East Anglia, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.323347.
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Sabokrouhiyeh, Nima. "Mass Transport Processes in vegetated wetlands-Optimal design of FWS wetlands." Doctoral thesis, Università degli studi di Padova, 2018. http://hdl.handle.net/11577/3422801.
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The hydraulic efficiency of wetlands for wastewater treatment was investigated as a function of wetland shape and vegetation density using a 2D depth-averaged numerical model. First, the numerical model was calibrated and validated against field data and then was applied to 8 hypothetical wetlands of rectangular and elliptical shape and different aspect ratio (i.e. 1/1 to 4/1). The vegetation density was varied from 0 to 1000 stems m-2. The effect of inlet-outlet configuration was analyzed by simulating the hydraulic response of wetlands with different alignment of the flow inlet and outlet and wetlands with multiple inlets. The resulting Residence Time Distributions (RTDs) were derived from numerical simulations of the flow field and the temporal evolution of the outlet concentration of a passive tracer injected at the inlet. The simulated velocity field demonstrated that wetland shape can have significant impact on the size of dead zone areas, which is also reflected in the RTD. Efficiency metrics associated with detention time and degree of mixing improved for an elliptical shape compared to a rectangular shape. An ellipse shape improved the wetland performance by reducing the area of dead zones at the corners, and thereby increasing the effective wetland volume contributing to the treatment process. Configurations in which inlet and outlet were located at opposite corners of the wetland, and wetlands with multiple inlets produced smaller dead zones, which reduced the variance of the RTD. The simulation results also revealed an interesting threshold behavior with regard to stem density. For stem density above 300 stems m-2, which is typical of treatment wetlands, the model predictions were not sensitive to the exact value of stem density selected, which simplifies the parameterization of models.
The presence of heterogeneous vegetation patterns in constructed wetlands was also analyzed by numerical model to simulate flow, mass transport and contaminant removal in a conceptual free water surface (FWS) wetland with heterogeneous vegetation patterns. The main objectives were (1) to quantify the effectiveness of FWS wetlands of different vegetation patterns in reducing water contamination and, if possible, give such patterns a physical interpretation to increase the insight into the governing processes, and (2) to evaluate if there exists an optimum pattern that would maximize contaminant removal. First, the model was calibrated and validated against survey data from a wide variety of vegetated types, sizes, and shapes of large, shallow wetlands, and subsequently, simulations were performed for different random vegetation fields characterized by imposed statistical properties, including mean, variance and correlation length of the stem density distribution. The patterns were designed to mimic vegetation patterns that occur in natural wetlands. Results show that the concentration reduction efficiency increased monotonically with average stem density, whereas mass removal had a peak for an intermediate value of average stem density. The ensemble average of the total mass removal decreased for increasing stem density variance and correlation length, because the presence of vegetation patches, localized regions of high or low stem density, promoted preferential flow paths. In particular, preferential flow paths parallel to the mean flow direction were found to reduce the hydraulic efficiency of wetlands by producing short-circuiting, whereas, for the same mean stem density, alternating stripes of stem density perpendicular to the flow direction provide higher concentration and mass reduction efficiencies. The results provide guidance for designers of constructed wetlands by developing a quantitative understanding of the hydraulic impact of spatial heterogeneity in vegetation. This quantitative analysis of the effect of wetland shape, inlet-outlet configuration and vegetation distribution can help engineers to achieve more efficient and cost-effective design solutions for wastewater treatment wetlands.L'efficienza idraulica delle zone umide per il trattamento delle acque reflue è stata studiata in funzione della forma delle zone umide e della densità della vegetazione utilizzando un modello numerico bidimensionale mediato sulla verticale. In primo luogo, il modello numerico è stato calibrato e validato sulla base di dati sperimentali e quindi è stato applicato a 8 zone umide ipotetiche di forma rettangolare ed ellittica con differenti proporzioni (cioè da 1: 1 a 4: 1). La densità della vegetazione è stata variata da 0 a 1000 steli / m2. Inoltre è stato analizzatol 'effetto della configurazione dell'ingresso-uscita,simulando la risposta idraulica di zone umide con diversi allineamenti dell'ingresso e dell'uscita e di zone umide con più ingressi. Dalle simulazioni numeriche del campo di flusso e dall'evoluzione temporale della concentrazione di uscita di un tracciante passivo iniettato all'ingresso sono state ricavate le risultanti distribuzioni del tempo di residenza (RTD). Il campo di velocità simulato ha dimostrato che la forma delle zone umide può avere un impatto significativo sulle dimensioni delle zone morte, che si riflette anche nella RTD. Le metriche di efficienza associate al tempo di detenzione e al grado di miscelazione migliorano per una forma ellittica rispetto a una forma rettangolare. Una forma ad ellisse migliora le prestazioni delle zone umide riducendo l'area delle zone morte agli angoli, aumentando così il volume efficace che contribuisce al processo di trattamento. Le Configurazioni in cui l'ingresso e l'uscita erano situati agli angoli opposti della zona umida, e le zone umide con più ingressi producevano zone morte più piccole, che riducevano la varianza della RTD. I risultati delle simulazioni hanno anche rivelato un comportamento soglia interessante per quanto riguarda la densità dello stelo. Per densità di vegetazione oltre 300 steli / m2, che è tipica delle zone umide deputate al trattamento di acque reflue, le previsioni del modello non erano sensibili al valore esatto della densità di vegetazione, il che semplifica la parametrizzazione dei modelli. anche La presenza di distribuzioni eterogenee di vegetazione nelle zone umide artificiali è stata analizzata mediante un modello numerico in grado di simulare il flusso, il trasporto di massa e la rimozione dei contaminanti in una zona umida concettuale a superficie libera (FWS). Gli obiettivi principali erano (1) quantificare l'efficacia delle FWS wetlands con diverse distribuzioni di vegetazione nel ridurre la contaminazione dell'acqua e, se possibile, dare a tali schemi un'interpretazione fisica per aumentare la conoscenza dei processi che li governano e (2) valutare se esiste un modello ottimale che massimizza la rimozione dei contaminanti. Innanzitutto, il modello è stato calibrato e validato rispetto a dati di indagine provenienti da un'ampia varietà di tipi, dimensioni e forme vegetate di vaste zone umide superficiali e successivamente sono state eseguite simulazioni per diversi campi random di vegetazione caratterizzati da proprietà statistiche imposte, tra cui media, varianza e lunghezza di correlazione della distribuzione della densità dello stelo. le distribuzioni di vegetazione sono state generate in modo da imitare le distribuzioni che si verificano nelle zone umide naturali. I risultati hanno mostrato che l'efficienza di riduzione della concentrazione aumentava monotonicamente con la densità di vegetazione media, mentre la rimozione di massa aveva un picco per un valore intermedio della densità di vegetazione media. La media di insieme della rimozione totale della massa diminuiva all'aumentare della varianza della densità di vegetazione e della lunghezza di correlazione, poiché la presenza di macchie di vegetazione, regioni localizzatecon densità di steli alta o bassa, promuoveva percorsi di flusso preferenziali. In particolare, è stato rilevato come percorsi di flusso preferenziali paralleli alla direzione media del flusso riducano l'efficienza idraulica delle zone umide producendo cortocircuiti, mentre, per la stessa densità media staminale, strisce alternate di densità dello stelo perpendicolari alla direzione del flusso forniscono maggiore concentrazione e efficienze di riduzione di massa. I risultati forniscono una guida per i progettisti di zone umide artificiali grazie allo sviluppo di una comprensione quantitativa dell'impatto idraulico dell'eterogeneità spaziale nella vegetazione. Questa analisi quantitativa dell'effetto della forma delle zone umide, della configurazione dell'ingresso e della distribuzione della vegetazione può aiutare gli ingegneri a realizzare soluzioni di progettazione più efficienti ed economicamente vantaggiose per le zone umide di trattamento delle acque reflue.
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King, Stanley W. "Mass transfer analysis of polyether sulfone and polyamide membranes modified by ion beam irradiation /." See Full Text at OhioLINK ETD Center (Requires Adobe Acrobat Reader for viewing), 2004. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=toledo1083875419.
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Thesis (M.S.C.)--University of Toledo, 2004.Typescript. "A thesis [submitted] as partial fulfillment of the requirements of the Master of Science degree in Chemical Engineering." Bibliography: leaves 109-113.
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da, Silva Cerozi Brunno, and Silva Cerozi Brunno da. "Phosphorus Dynamics, Mass Balance and Mineralization in Aquaponics Systems." Diss., The University of Arizona, 2016. http://hdl.handle.net/10150/620832.
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This study involves tracing inputs, partitioning, and outputs of phosphorus (P) through an aquaponics system. A mathematical model was developed to describe the dynamics of phosphorus in an aquaponics nutrient solution, and to maximize P use efficiency and minimize P waste. We assessed the influence of pH on the availability and speciation of phosphorus in an aquaponics nutrient solution. By using Visual MINTEQ, a freeware chemical equilibrium model for the calculation of element speciation, solubility equilibria, and sorption for natural waters, it was discovered that high pH values favor the formation of calcium phosphate complexes, decreasing the concentration of free phosphorus in aquaponics nutrient solutions. In addition, the mineralization of organic phosphorus in aquaponics systems was evaluated using treatments with phytase supplementation to fish diets, and incorporation of a microbial inoculant in the aquaponics nutrient solution. Overall, dietary phytase and microorganisms promoted phosphorus mineralization and enhanced phosphorus utilization in aquaponics systems. In the end, we conclude that aquaponics systems can keep the same growth performance and quality of vegetable crops grown in conventional systems when the availability and dynamics of phosphorus are well managed.
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Determan, Matthew D. "Experimental and Analytical Investigation of Ammonia-Water Desorption in Microchannel Geometries." Thesis, Georgia Institute of Technology, 2005. http://hdl.handle.net/1853/7149.
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An experimental and analytical study of a microchannel ammonia-water desorber was conducted in this study. The desorber consists of 5 passes of 16 tube rows each with 27, 1.575 mm outside diameter x 140 mm long tubes per row for a total of 2160 tubes. The desorber is an extremely compact 178 mm x 178 mm x 0.508 m tall component, and is capable of transferring the required heat load (~17.5 kW) for a representative residential heat pump system. Experimental results indicate that the heat duty ranged from 5.37 kW to 17.46 kW and the overall heat transfer coefficient ranges from 388 to 617 W/m2-K. The analytical model predicts temperature, concentration and mass flow rate profiles through the desorber, as well as the effective wetted area of the heat transfer surface. Heat and mass transfer correlations as well as locally measured variations in the heating fluid temperature are used to predict the effective wetted area. The average wetted area of the heat and mass exchanger ranged from 0.25 to 0.69 over the range of conditions tested in this study. Local mass transfer results indicate that water vapor is absorbed into the solution in the upper stages of the desorber leading to higher concentration ammonia vapor and therefore reducing the rectifier cooling capacity required. These experimentally validated results indicate that the microchannel geometry is well suited for use as a desorber. Previous experimental and analytical research has demonstrated the performance of this microchannel geometry as an absorber. Together, these studies show that this compact geometry is suitable for all components in an absorption heat pump, which would enable the increased use of absorption technology in the small capacity heat pump market.
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Staudinger, Jeff. "Evaluation of mass transfer correlations for packed column air stripping of volatile organic contaminants from water supplies." Thesis, Virginia Polytechnic Institute and State University, 1986. http://hdl.handle.net/10919/101153.
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The application of packed column air stripping systems to the removal of volatile organic contaminants (VOCs) from drinking water sources was investigated. The crucial element for the design of such systems exists in obtaining accurate predictions of mass transfer rates. The first phase of this study evaluated three semi-empirical correlations available for predicting packed column mass transfer rates. From this initial screening, the Onda model was selected for further investigation. A test data base was established from water treatment pilot study results reported in the literature. Ten separate studies were selected for evaluation, encompassing approximately 450 data points. Eleven different VOCs were encountered in these investigations, and the basic packing types tested included rings, saddles, Tri-Packs, and Tellerettes. Comparison of measured mass transfer rates with the corresponding rates predicted by the Onda correlation yielded a relative standard deviation of 17%. A ± 30% accuracy value was therefore assigned to the model based on 90% confidence limits. This assessment agrees with the observed accuracy of the correlation for the chemical engineering-based system results utilized in the model's original derivation. From the overall evaluation, no severe deficiencies and/or limitations with the Onda correlation were noted. In particular, gas-phase resistance predictions appeared reasonably accurate. However, further investigative studies involving observed column performance with larger packing materials (≥2 inches in nominal size) is encouraged to verify the accuracy of the correlation for such situations.
Within the context of the evaluation procedure, several related areas were investigated. First, Henry's constant temperature relations reported in the literature were established within approximately 20% for common VOCs at low concentration levels. Secondly, the transfer unit performance model for calculating observed mass transfer rates was found sensitive to experimental measurement errors below a stripping factor of 1.5. Therefore, measured results obtained under such operating conditions must be viewed with appropriate caution. Finally, economic design boundaries for column operational parameters were established based upon optimization study results reported in the literature.M.S.
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Svengren, Henrik. "Water splitting by heterogeneous catalysis." Doctoral thesis, Stockholms universitet, Institutionen för material- och miljökemi (MMK), 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-148181.
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A sustainable solution for meeting the energy demands at our planet is by utilizing wind-, solar-, wave-, thermal-, biomass- and hydroelectric power. These renewable and CO2 emission-free energy sources are highly variable in terms of spatial and temporal availability over the Earth, introducing the need for an appropriate method of storing and carrying energy. Hydrogen has gained significant attention as an energy storage- and carrier media because of the high energy density that is exploited within the ‘power-to-gas’ process chain. A robust way of producing sustainable hydrogen is via electrochemical water splitting. In this work the search for new heterogeneous catalyst materials with the aim of increasing energy efficiency in water splitting has involved methods of both electrochemical water splitting and chemical water oxidation. Some 21 compounds including metal- oxides, oxofluorides, oxochlorides, hydroxide and metals have been evaluated as catalysts. Two of these were synthesized directly onto conductive backbones by hydrothermal methods. Dedicated electrochemical cells were constructed for appropriate analysis of reactions, with one cell simulating an upscale unit accounting for realistic large scale applications; in this cell gaseous products are quantified by use of mass spectrometry. Parameters such as real time faradaic efficiency, production of H2 and O2 in relation to power input or overpotentials, Tafel slopes, exchange current density and electrochemical active surface area as well as turnover numbers and turnover frequencies have been evaluated. Solubility, possible side reactions, the role of the oxidation state of catalytically active elements and the nature of the outermost active surface layer of the catalyst are discussed. It was concluded that metal oxides are less efficient than metal based catalysts, both in terms of energy efficiency and in terms of electrode preparation methods intended for long time operation. The most efficient material was Ni-Fe hydroxide electrodeposited onto Ni metal foam as conductive backbone. Among the other catalysts, Co3Sb4O6F6 was of particular interest because the compound incorporate a metalloid (Sb) and redox inert F and yet show pronounced catalytic performance. In addition, performance of materials in water splitting catalysis has been discussed on the basis of results from electron microscopy, solubility experiments and X-ray diffraction data.
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Sadd, Peter Alan. "The effect of surfactants on heat and mass transfer to water drops in air." Thesis, University of Surrey, 1987. http://epubs.surrey.ac.uk/843252/.
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The temperatures and evaporation rates of surfactant-contaminated droplets were determined under controlled conditions. The surfactants used were sodium stearate, sodium palmitate, sodium myristate and sodium laurate. The drops were suspended on fine glass fibres or thermocouples in an environmental cell maintained at known temperature and humidity, and the evaporation rate was determined by optical measurement of the change of diameter with time. The results showed an early evaporation following a "clean" model, with a relatively sharp transition to a regime of "contaminated" evaporation kinetics. Simultaneous measurements of temperature and evaporation rate showed that the contaminants had no effect on heat transfer, i.e. their effect was limited to forming an additional mass transfer resistance. This mass transfer resistance increased strongly with initial surfactant concentration. Surfactants with longer carbon chains produced higher resistances, but after a longer delay. The partial differential equations describing surfactant diffusion within an evaporating drop were set up and solved, and an approximate analytical solution was shown to agree well with a numerical solution. By assuming that the surfactants retarded evaporation at the drop surface both by presenting a diffusional resistance to water transport and by vapour pressure lowering, a model was constructed to predict the evaporation behaviour of contaminated drops. It predicted the results obtained with sodium stearate well, but was unable to explain the results for shorter chain surfactants which were complicated by their adsorption behaviour at the surfactant-water interface. This model of single drop evaporation was extended to describe the evaporation of contaminated aerosols and used in an attempt to explain the measurements of Raper et al. (1982). Their results could not be explained quantitatively by a surfactant contaminant (though a surfactant would have produced similar qualitative features) and were probably caused by experimental error.
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Sandery, Paul Anthony, and paul sandery@flinders edu au. "Seasonal Variability of Water Mass Properties in Bass Strait: Three-dimensional oceanographic modelling studies." Flinders University. Chemistry, Physics and Earth Sciences, 2007. http://catalogue.flinders.edu.au./local/adt/public/adt-SFU20070831.093503.
Full textAbstract:
The climatology of the seasonal cycle of water mass variation and transformation in Bass Strait, south-eastern Australia, is studied using a high resolution three-dimensional sigma-coordinate hydrodynamic model coupled with data from observations and previous studies.
Model forcing consists of the principal tidal constituents from the Australian National Tidal Centre and long-term monthly mean atmospheric forcing fields from NCEP reanalysis. The initial density field is established using temperature and salinity means and annual and semi-annual harmonics from the CARS2000 hydrographic atlas. This is also used to prescribe incoming water mass properties at model open-sea boundaries with seasonal variation. Far-field forcing is included with open-sea boundary parameterisation of residual sea-level representing both the South Australian Current and the East Australian Current. Lagrangian and Eulerian tracer methods are used to derive transport timescales, such as age, residence times and flushing times. These are used to examine and summarise model predictions and as a diagnostic tool in sensitivity studies.
Currents, sea-level and water mass properties in the model compare favourably with previous studies and observations, despite limitations in the model and in the data used for comparison. The seasonal cycle, in model results, is characterised by formation of a shallow (< 20 m) saltier surface-layer in late spring to summer and subsequent downward mixing and erosion of the salinity field in autumn to winter with water mass from the west. This leaves behind water mass with positive age and salinity anomalies in areas of low flushing. In late winter-early spring most parts of this water mass leave the Strait interior. These areas are thought to be related to the source water of the Bass Strait Cascade. The residual circulation in all model experiments is shown to be related to seasonal-mean sea-level anomalies, arising from both barotropic and baroclinic adjustment, both in and surrounding the Strait.
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Hirayama, Y. "Heat and mass transfer regimes for room cooling and dehumidification using chilled water radiators." Thesis, Cranfield University, 1998. http://hdl.handle.net/1826/4028.
Full textAbstract:
The application of room radiators for the purposes of cooling and dehumidification in
buildings for hot and humid climates is investigated. The radiator is purposely brought
below the dew point temperature of the room air thereby creating condensation on the
radiator surface. The condensate is then collected at the base of the radiator and
removed. Mathematical models describing the heat transfer regime within a room when
this system is used have been verified using climate chamber tests. The models show
good agreement with the experimental results for radiator (a) with a height of 1 m, but
not as accurate for radiator (b) with a height of 2 m. The underestimation of the real
values by the convective heat transfer model used for the geometric construction of the
radiator tested is attributed to the effect of air entrainment along the height of the
radiator. Results indicate the importance of the radiant transfer component of the
radiator, as well as its effectiveness to remove latent heat. In view of improving thermal
comfort and energy efficiency, the implication of the results from this investigation of the
heat transfer characteristics of the radiator used for cooling and dehumidification is such
that the chilled radiator may offer a definite alternative to conventional air conditioning
systems. Partial or full matching of the sensible and latent component of the radiator
output to the load requirements of a building should prove particularly effective in hot
and humid regions where the latent heat factor of the total cooling load is high.
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Weitbrecht, Volker [Verfasser]. "Influence of dead-water zones on the dispersive mass transport in rivers / Volker Weitbrecht." Karlsruhe : Univ.-Verl. Karlsruhe, 2004. http://d-nb.info/972080783/34.
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Tisch, Timothy Daniel. "Seasonal variability of the geostrophic velocity and water mass structure off Point Sur, California." Thesis, Monterey, California. Naval Postgraduate School, 2013.
Find full textAbstract:
Approved for public release, distribution unlimitedThe Point Sur Transect was established in 1987 by the Department of Oceanography at the Naval Postgraduate to further the present understanding of long term variability of current and temperature in eastern boundary regions. Seven of these cruises were selected for seasonal comparisons of alongshore geostrophic velocities and water mass characteristics. Geostrophic velocities were referenced to the 1000 decibar surface based on available PEGASUS observations. Anomalies of spiciness calculated as deviations from an average offshore T-S profile have been used to identify the location and spatial extent of the eastern Pacific water masses. The California Undercurrent (positive spiciness anomaly) was a prominent feature in 6 of the 7 sections analyzed, and was very weak during a period of uncommonly strong equatorward wind stress. The position of the core varied from 12 to 42 km from shore while its strength varied from 10 to 35 cm s, with the maximum flow occurring in winter. The vertical extent of the Undercurrent core covered a region of the continental slope from 70 to 460 m throughout these seven cruises. The nature of the alongshore geostrophic velocities and the location and spatial extent of the undercurrent appear strongly related to specific wind events, both local and remote. Remote wind forcing from the south was believed to cause anomalous, strong poleward flow throughout the entire water column during a period of local equatorward wind stress, while an intrusion of warm, salty water was believed to cause a deep penetration (to 700 m) of the California Current in winter.