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Davies, M. W. "Modelling deposition environments around superheater tubes." Thesis, Cranfield University, 2011. http://dspace.lib.cranfield.ac.uk/handle/1826/7866.
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In an important initiative to reduce carbon dioxide emission from pulverized fuel boilers, coal is now co-fired with biomass. During the combustion process, however, chlorine and sulphur in chemical compounds associated with sodium and potassium are released in a form which can deposit onto and then corrode the steel heat exchanger tubes. The deposition and corrosion can have serious implications for the power generation industry because the corrosive damage on heat exchange tubes can shorten the operational life of the boilers and lead to significant economic penalties. The deposition and corrosion processes have been widely studied but eliminating the deposits and corrosive materials is still a challenging problem. Computational fluid dynamics (CFD) has been used to model the deposition processes and it mainly focuses on experimentally deriving constants in the models that capture some aspects of the problem such as the motion behaviour of aerosols. However, using CFD has a limitation that results in periodic instability when solving the models with numerical computation. Modelling deposition environments around superheater tubes is a complex problem as many aspects, such as particle motion, condensation of matter and continuous combustion of particles, should be considered.This thesis has: (1) developed a new mathematical approach that uses mesh-free methods to solve Hamilton’s equations with a consideration of the total energy of the system, where the Hamilton’s equation is scale independent; (2) developed a model that can simulate the mass accumulation process based on graph and combinatorics theory; (3) developed a model depicting the continuous combustion of particles in motion; (4) developed a model depicting the behaviour of changing matter states; (5) developed a model depicting the vapour phase deposition on particles; and (6) verified the developed models with case studies. This work shows the importance of homogenous and heterogeneous vapour depositions on binding particles onto superheater tubes.
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Whitham, A. G. "Transport and deposition of pyroclastic materials in subaqueous environments." Thesis, University of Cambridge, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.355512.
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Fones, Gary R. "Atmospheric deposition of trace metals to urban and coastal environments." Thesis, University of Central Lancashire, 1996. http://clok.uclan.ac.uk/20067/.
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The atmospheric flux (wet and dry) of trace metals (Ni, Co. Cu, Pb, Cd, Al and Na) to the Irish Sea and the North-West of England is presented. The fluxes were calculated from determined trace metal concentrations of aerosols (Al, Fe, Mn, Cd, Co, Cr, Cu, Na, Ni, Pb, V and Zn) and rainwaters (Ni, Co, Cu, Pb, Cd, Al and Na), which were collected using specially designed sampling equipment. The particulate material was analysed using inductively coupled plasma - mass spectroscopy (ICPMS) and also atomic absorption spectroscopy techniques after a complete aciddigestion (HFIHNO3). The dissolved rainwater metal concentrations were determined using the electroanalytical technique adsorptive cathodic stripping voltammetry (ACSV). This technique also enabled dissolved metal Organic complexation to be determined in the rainwater. The results indicated that the trace metal aerosol and rainwater concentrations detected for the Irish Sea and urban areas vary considerably during an annual period. This can be attributed to (i) air mass source and (ii) rainwater washout. Geometric mean aerosol concentrations (ng m 3) were calculated for the Irish Sea aerosol (Al, 210; Fe, 159; Mn, 6.2; Cd, 0.26; Co, 0.17; Cr, 2.0; Cu, 5.3; Na 1140; Ni, 4.2; Pb, 19; V, 4.1; Zn, 32) and North-West England aerosol (Al, 365; Fe, 589; Mn, 21; Cd, 0.80; Co, 0.68; Cr, 13; Cu, 17; Na 2208; Ni, 16; Pb, 45; V, 7.7; Zn, 153) along with total (dissolved + particulate) volume weighted mean concentrations (j.ig l') for the Irish Sea rainwater (Al, 32; Cd, 0.05; Co, 0.05; Cu, 1.8; Na 1998; Ni, 1.1; Pb, 0.73) and North-West England rainwater (Al, 72; Cd, 0.14; Co, 0.15; Cu, 2.9; Na 1274; Ni, 1.7; Pb, 1.82). Air mass analysis studies illustrated the affect on the aerosol trace metal concentrations. For Fe, Mn, Cd, Cu. Pb, V and Zn the Irish Sea aerosol concentrations decreased in the order E> S > N > W. Calculated total inputs to the Irish Sea for Cu (131 t yr:'), Pb (82 t yr') and Cd (3.2 t yr.') were of similar magnitude to total riverine inputs and considerably greater than those of direct discharges (sewage and drainage) for Cu and Pb. The fate of aerosol associated trace metals in the Irish Sea was investigated by laboratory simulation aerosol seawater/rainwater solubility studies. These studies indicated fast dissolution kinetics for crust-rich and urban-rich aerosol trace metals, with equilibrium times of - 5 minutes for Ni, Co, Cu, Pb and Cd. Similar solubility studies performed on collected Irish Sea aerosols in seawater and artificial rainwater indicated solubilities increased in the order Co (32 %) c Pb (37 %) < Ni (38 %) < Cd (46 %) < Cu (58 %) for seawater. These were correspondingly higher in artificial rainwater, Co (37 %) <Ni (41 %) < Pb (44 %) < Cd (52 %) < Cu (63 %). These solubilities were found to be both lower than field determined rainwater solubilities, Pb (63 %) <Ni (69 %) c Co (70 %) < Cd (79 %) < Cu (82 %). This difference being attributed to condensation and evaporation cloud cycles which can reduce the pH of cloudwater to - 2. Within the dissolved fraction, organic complexation was detected for Cu (32 %), Cd (32 %), Pb (34 %), Ni (35 %) and Co (38 %) indicating that the atmosphere is a source of potential metal complexing material. Calculation of net inputs to the Irish Sea highlights the importance of wet deposition. The wet to dry ratio for the selected metals in the Irish Sea increased in the order Co (1.7) !~ Ni (1.7) < Cu (2) !~ Cd (2) <Pb (2.1). Net atmospheric inputs to the North - East Irish Sea are of the same magnitude for Ni (7 t yr.'), Cu (17 yr.j, Pb (10 t yr.') and Cd (0.36 t yr:') when compared to riverine inputs.
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Manuja, Archit. "Total Surface Area in Indoor Environments." Thesis, Virginia Tech, 2018. http://hdl.handle.net/10919/83384.
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Certain processes in indoor air, such as deposition, partitioning, and heterogeneous reactions, involve interactions with surfaces. To accurately describe the surface-area-to-volume ratio in a room, we have characterized the surface area, volume, shape, and material of objects in five bedrooms, four kitchens, and three offices. Averaged over all types of rooms, the ratio of surface area with contents to that without contents was 1.7 ± 0.2 (mean ± standard error), and the ratio of volume of freely moving air to volume of the entire space was 0.89 ± 0.05. Ignoring contents, the surface-area-to-volume ratio was 1.9 ± 0.3 m-1; accounting for contents, the ratio was 3.7 ± 1.2 m-1. Ratios were not significantly different between room types and were comparable to those measured for 33 rooms in a similar study. Due to substantial differences in the design and contents of kitchens, their ratios had the highest variability among the three room types. On average, the contents of bedrooms, kitchens, and offices increase their surface area by 70% and decrease their volume of freely moving air by 11% compared to an empty room. The most common shape of objects in a room was a flat plate, while each room also had many irregularly-shaped objects. Paint and wood were the two most common materials in each room, although the distribution of materials varied by room type. The results of this study can be used to improve understanding of the behavior of gases and particles in indoor environments.<br>Master of Science
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Maheras, Anastasia Francis. "Elemental and reactive gaseous mercury deposition and diurnal cycles over terrestrial environments." Thesis, Massachusetts Institute of Technology, 2011. http://hdl.handle.net/1721.1/114365.
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Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2011.<br>Cataloged from PDF version of thesis.<br>Includes bibliographical references (pages 88-93).<br>The atmospheric component of the global biogeochemical mercury cycle was studied to determine the mechanisms behind diurnal trends and amplitudes in elemental and reactive gaseous mercury concentrations over terrestrial environments. This analysis was done using the 3D GEOS-Chem chemical transport model and the creation of a simple one-box model. Mercury is a significant neurotoxin for humans and other species that has been addressed in the policy realm on both national and international levels. Being able to model atmospheric mercury processes correctly is an important part of regulation and policy drafting. GEOS-Chem model results were compared with Weiss-Penzias et al. [2009] measurements for three Nevada, USA sites. The magnitude of elemental mercury concentrations differed by 0.07-0.2 ng/m3 , with GEOS-Chem underestimating concentrations due to an under-representation of mercury emissions at naturally enriched sites. The amplitude of reactive gaseous mercury diurnal variations differed by a factor of 3-4, with GEOS-Chem underestimating the diurnal trend. Based on the diurnal nature of this error, it is hypothesized that GEOS-Chem under represents the magnitude of elemental mercury emissions, the amount of oxidation occurring in the atmosphere, and the scale of entrainment from the free troposphere.<br>by Anastasia F. Maheras.<br>S.B.
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Black, R. Bernard. "Petrology, sedimentology and depositional environments of the Prairie Grove Member of the Hale Formation (Morrowan) in northwestern Arkansas /." Access abstract and link to full text, 1986. http://0-wwwlib.umi.com.library.utulsa.edu/dissertations/fullcit/8702931.
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Zolaly, Abdul Badea Mahza A. "The deposition of metals in different environments with special reference to Jeddah, Saudi Arabia." Thesis, University of Sheffield, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.280686.
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CARVALHO, CARLOS VITOR DE ALENCAR. "SIMULATION OF TRANSPORT AND DEPOSITION OF SILICICLASTIC SEDIMENTS IN PLATAFORM, SLOPE, AND BASIN ENVIRONMENTS." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2002. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=3529@1.
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CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO<br>GRUPO DE TECNOLOGIA DE COMPUTAÇÃO GRÁFICA - PUC-RIO<br>A geologia sedimentar trata do estudo dos processos
físicos, químicos e biológicos atuantes na superfície da
Terra não só no presente como também ao longo de toda a sua
evolução. Em função disso, ela pode ser aplicada em diversos
campos, como, por exemplo, no estudo da formação de
combustíveis fósseis. Um dos focos principais da geologia
sedimentar reside em determinar os parâmetros e processos
pelos quais as bacias sedimentares são preenchidas. Neste
trabalho é apresentado o desenvolvimento de um simulador
numérico de sedimentação tridimensional, chamado de STENO,
com ênfase nos processos deposicionais em ambientes de
plataforma, talude e bacia. O algoritmo do simulador é
baseado nos conceitos quantitativos formulados pela
Estratigrafia de Seqüências, como mecanismos de controle
primário da arquitetura dos estratos sedimentares, e em
uma análise numérica para simulação do fluxo bidimensional
de um fluido incompressível, em regime permanente, não
viscoso, em função da batimetria da região a ser modelada
através de um grid regular definido pelo usuário. O campo
de velocidades, calculado a partir das velocidades de
aporte de sedimentos e das velocidades de corrente, é
utilizado para determinar a direção de escoamento dos
sedimentos (linhas de correntes). A abordagem dada pelo
algoritmo do STENO é inovadora em termos dos algoritmos
existentes, pois considera que os sedimentos são
transportados hidrodinamicamente, isto é, na direção x e y
eles são transportados seguindo as linhas de corrente e na
direção z a movimentação/deposição dos sedimentos é
controlada pelo ângulo de estabilidade de cada fração
litológica (areia, silte ou argila) e pelo volume do espaço
disponível para acomodação em cada uma das colunas formadas
a partir das células do modelo discretizado.<br>Sedimentary Geology deals with the study of the physical,
chemical and biological processes operating in the surface
of the Earth, not only in the present days, but also along
all History. Therefore, it can be applied in miscellaneous
fields, as, for example, in the study of fossils fuels
formation. One of the main focus of sedimentary geology
inhabits in determining the parameters and processes for
which the sedimentary basins are filled. In this work the
development of a numerical simulator of sedimentation 3D,
called STENO is presented, with emphasises the depositary
processes in platform, slope, and basin environments. The
algorithm of the simulator is based on the formulated
quantitative concepts for Sequence Stratigraphy, as
mechanisms of primary control of the architecture of
sedimentary stratus, and in a numerical analysis for
simulation of the 2D steady-state flow of a incompressible
fluid, not viscous, in function of the bathymetry of the
region represented by one regular grid defined by the user.
The velocity field calculated from boundary conditions
(sediment aport velocity and for field stream velocity) it
is used to determine the direction of draining of the
sediments (streamlines). The algorithm of STENO is
innovative because it considers that the sediments are
carried hydrodynamicsly, that is, in direction x and y they
are carried following streamlines and in direction z. The
movement/deposition of sediments is controlled by an angle
of stability of each lithology fraction (sand, silte or
clay) and by the volume of the available space for
accommodation in each one of the columns formed in the
cells of the discretized model.
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Quevedo, Ivan. "Transport and deposition of quantum dots and model polystryene nanoparticles in granular aquatic environments." Thesis, McGill University, 2013. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=119385.
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Quantum dots (QDs) are luminescent semiconductor nanoparticles with relevant applications in different fields, including medical imaging, solar cells, and sensors. However, toxic effects in living organisms have been reported, and upon release, the potential ecotoxicological risks of QDs will be directly related to their transport and fate. The objective of this research was to evaluate the transport and deposition of different QDs in systems representative of natural subsurface environments and engineered granular filtration processes. Two experimental approaches were used: (i) laboratory scale columns packed with granular materials representative of the soil or filter matrix, and (ii) a quartz crystal microbalance with dissipation monitoring (QCM-D) using sensors coated with materials representative of grain-water interfaces. The transport and deposition of the QDs were determined over a broad range of solution chemistries (i.e., ionic strength, pH, cation type, natural organic molecules (NOM)). In all cases, the deposition experiments were complemented with an appropriate physicochemical characterization of the particles and collectors. In experiments conducted with packed columns, the transport potential of a CdSe QD, a CdTe QD and model nanosized polystyrene particles was systematically investigated in two water-saturated granular matrices: (i) clean quartz sand and (ii) loamy sand obtained from Québec farm. This study provided a good starting point for the comparison of the transport behavior of engineered nanoparticles in quartz sand versus soil matrices (loamy sand), where greater retention was observed. The results obtained suggest that differences in retention are likely related to the binding affinity of surface-modified nanoparticles for specific soil constituents.In experiments conducted with a QCM-D, the deposition kinetics of polymer-coated QDs were compared with those measured for two different polystyrene latex nanoparticles onto model environmentally relevant collector surfaces (SiO2, Al2O3, or Al2O3 coated with NOM). The results showed that QD retention is relatively low compared to that of polystyrene latex particles, and in the presence of NOM, significantly lower deposition rates of QDs were observed. Overall, the data suggested that these phenomena could be attributed to the surface coating (polymers) used to stabilize the QDs, likely due to "electrosteric repulsion". In the final series of experiments, the deposition kinetics of functionalized silicon-nanocrystals (Si-NCs) was compared by means of: columns packed with quartz sand, and a QCM-D with SiO2 coated crystals (as a model sand surface). The Si-NCs used here were functionalized with carboxylic acids of varying alkyl-chain length, and in general, experiments conducted with both techniques revealed that the mobility of Si-NCs increases with longer alkyl-chains. QCM-D provided further insight on the nanoparticle deposition behavior, whereby the output parameters (i.e., frequency and dissipation) indicated how rigidly the ENPs are bound to the surface. Yet, the interpretation of nanoparticle deposition behavior by QCM-D may be limited by the size of the particle assessed; as it was determined that in the presence of large aggregates, the acquired frequency shifts were not proportional to the deposited mass.<br>Les points quantiques (PQs) sont des nanoparticules semi-conductrices luminescentes ayant des applications intéressantes et prometteuses dans différents domaines, comme l'imagerie médicale, les cellules solaires ou les senseurs. Cependant, des effets toxiques dans les organismes vivants ont été découverts, et après la libération des PQs dans l'environnement, les risques possibles éco-toxicologiques des PQs seront directement liés à leur transport et leur destin. L'objectif de cette recherche était d'évaluer le transport et le dépôt de PQs dans différents systèmes représentatifs des milieux naturels du sol et aussi des procédés de filtration granulaire. Deux approches expérimentales ont été utilisées: (i) des colonnes (collecteurs) remplies de matériaux granulaires (correspondant à la matrice du sol), et (ii) une microbalance à cristal de quartz avec dissipation d'énergie (QCM-D) en utilisant des capteurs recouverts de matériaux pouvant modéliser les différentes interfaces sol-eau. Le transport et le dépôt des PQs ont été déterminés sur une large gamme de chimies de solution (c.-à-d, force ionique, pH, type de cation et macromolécules organiques naturelles). Dans tous les cas, les mesures de dépôt ont été complétées par une caractérisation physico-chimique appropriée pour les particules et les collecteurs.Dans des expériences menées avec des colonnes, le potentiel de transport d'un PQ de CdSe, d'un PQ de CdTe et d'une nanoparticule modèle de latex polystyrène a été systématiquement étudié dans deux matrices granulaires saturées d'eau: (i) du sable de quartz propre et (ii) du sable glaiseux obtenu d'une ferme québécoise. Cette étude a servi de point de départ pour comparer le comportement de transport des nanoparticules dans le sable de quartz d'une part et avec les matrices du sol (sable glaiseux) d'autre part, où, d'ailleurs, une plus grande rétention a été observée. Les résultats obtenus suggèrent que les différences de rétention sont probablement liées à ce qui constitue l'affinité des nanoparticules modifiées en surface par les constituants spécifiques du sol.Dans des expériences menées par QCM-D, les dépôts cinétiques de PQs enrobés de polymères ont été comparés à ceux mesurés pour deux différents types de nanoparticules de latex sur des surfaces collectrices modèles représentatives de l'environnement (c.-à-d, SiO2, Al2O3, Al2O3 ou encore recouvertes de macromolécules organiques naturelles). Les résultats ont montré que la rétention des PQs est relativement faible par rapport à celle des particules de polystyrène, et peu d'interaction se produit entre les PQs et les macromolécules organiques naturelles. Dans l'ensemble, les données suggèrent que ces phénomènes pourraient être attribués à une "répulsion électro-stérique" de la couche de surface (polymères) utilisée pour stabiliser les PQs.Dans la dernière série d'expériences, la cinétique de dépôt des nanocristaux fonctionnalisés à base de silicium (NCs de Si), a été comparé à l'aide de : des colonnes remplies avec du sable de quartz, et un QCM-D avec de cristaux revêtus de SiO2 (comme surface du sable modèle). Les NCs de Si utilisés ici ont été fonctionnalisés par des acides carboxyliques avec différentes longueurs de chaîne alkyle, où la mobilité de NCs de Si augmente avec des chaînes d'alkyle plus longues. QCM-D a aussi permis de mieux comprendre le comportement de dépôt de NCs de Si, de sorte que les paramètres de sortie (c.-à-d, la fréquence et la dissipation) indiquent comment les particules sont rigidement liées à la surface. Néanmoins, en présence de grands agrégats, l'interprétation du comportement de dépôt de nanoparticules par QCM-D peuvent être limitée; comme il a été déterminé, les variations de fréquence acquise pourraient ne pas être proportionnels à la masse déposée.
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Kerns, Jessica L. "Contrasting depositional environments of North American black shales illuminated through geochemical techniques and modern analogs /." free to MU campus, to others for purchase, 2004. http://wwwlib.umi.com/cr/mo/fullcit?p1421149.
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Hemer, Mark A. "The oceanographic influence of sedimentation on the continental shelf : a numerical comparison between tropical and Antarctic environments /." Connect to this title online, 2003. http://adt.lib.utas.edu.au/public/adt-TU20051223.102442.
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Segwabe, Tebogo. "The geological framework and depositional environments of the coal-bearing Karoo strata in the Central Kalahari Karoo Basin, Botswana." Thesis, Rhodes University, 2009. http://hdl.handle.net/10962/d1005567.
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The investigation of the geological history (i.e., stratigraphy and sedimentology) and the dynamics of coal depositional environments, in particular, the forces responsible for changes in the accommodation space (e.g., subsidence vs. sedimentation rates) in the Permian coal-bearing Karoo strata in the Central Kalahari Karoo Basin (Botswana) revealed new details about the depositional processes and environments. Detailed review of the temporal and spatial stratigraphic variation of the coal-bearing Ecca Group successions via the analysis of facies changes based on core descriptions, gamma logs, field observations and palaeo-current measurements, lead to the identification of two main informal stratigraphic units, namely the Basal and Upper Units. The Basal Unit is characterised by an upward-coarsening succession, and it is interpreted as a product of a progradational deltaic setting (i.e., regressive deltaic cycle). This is followed by five sequences of fining-upward successions of sandstones and siltstones in the Upper Unit, interpreted as deposits of distributary channels (the basal arenaceous member) capped by finer argillaceous sequences of the deltaic floodplains (the upper coal-bearing member). The Upper Unit thus is interpreted as a delta plain facies association which was formed during transgressive phases when conditions for coal-quality peat accumulation (e.g., high water table) were present and the available accommodation space was partly controlled by tectonic uplift (repeated?) at basin margins. Limited palaeo-current analysis indicates deposition by channels flowing from the east, south-east and north-east. The lack of good quality exposures hampers the reconstruction of the plan form of the channel patterns. However, the little available evidence indicates a high-energy fluvio-deltaic system with irregular discharge and a high proportion of bedload sediments. Coal-seam thickness in the upper coal-bearing member reflect the complex control of the geological processes associated with and following peat formation, such as differential compaction of the underlying lithology, and the erosive or protective nature of the immediately overlying lithology.
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Brasseur, Philippe. "Experimental Study of the Growth and Stable Water Isotopes of Ice Formed by Vapour Deposition in Cold Environments." Thesis, Université d'Ottawa / University of Ottawa, 2016. http://hdl.handle.net/10393/34487.
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Ice formed by water vapour deposition has been identified in different terrestrial environments: 1) in the atmosphere; 2) at the ground’s surface; 3) in caves; 4) in seasonally frozen ground; and 5) in perennially frozen ground (permafrost). Thus far, ground ice formed by diffusion and deposition of vapour in soils (types 4 and 5) has rarely been studied in a natural setting and remains one of the most poorly described ice types on Earth. This thesis focuses on the dynamics of deposition and sublimation of atmospheric water vapour into permafrost and the isotopic signature (D/H and 18O/16O) of the emplaced ground ice under different experimental conditions. Ground ice was produced in sediments with different thermo-physical characteristics (glass beads, JSC Mars-1 simulant). After a two-month growth period, the higher porosity sediments (JSC) had more than 7x the gravimetric water content than the lower porosity soil. Ground ice profiles had a distinct concave downwards shape due to the decrease in saturation vapour pressure with depth. Results also indicate that vapour deposited ground ice has a distinct δD-δ18O composition that plots near regression slope value of 8. Pore water isotopes plot below the global meteoric water line (GMWL) when the source of moisture is directly on top of the sediments. If an air gap is introduced between the source of moisture and the sediments, the pore water isotopes shift above the GMWL due to re-sublimation at the ground surface. Overall, this thesis addressed some fundamental knowledge gaps required to better understand the growth and isotopic evolution of ground ice emplaced by vapour deposition.
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Rizvi, Toor-E.-Aiman. "Fireside corrosion in oxy-fuel environments and the influence of fuel and ash characteristics on corrosion and deposition." Thesis, University of Leeds, 2014. http://etheses.whiterose.ac.uk/7654/.
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The development of advanced techniques (such as carbon capture and storage) for future power plants and the implementation of retrofit technologies to existing ones (like biomass co-firing) in order to reduce pollutant emission, has raised several concerns for the power industry. One such problem, which also forms the basis of this thesis, is the effect of these measures on corrosion and deposition of the boiler heat transfer surfaces. This research work can be divided into two parts. The first part involved studying the corrosion behaviour of a typical waterwall and a superheater material under simulated oxy-fuel environments with and without the influence of an ash deposit. A custom-built, laboratory scale, corrosion rig with the ability to simulate a range of flue gas compositions and temperatures, in addition to generating a heat flux through the specimen, was set up for this purpose. The second part of this work deals with evaluating the properties of a UK power station coal and four biomass samples with the help of laboratory techniques and thermodynamic modelling in order to predict their fusion and deposit forming tendencies in combustion systems. A series of experiments were performed on the corrosion rig to assess the influence of individual variables on the rate of corrosion. The results indicated that the increased concentration of SO2 in oxy fuel combustion due to recycling of the flue gas, can lead to an increase in corrosion rates especially in the presence of reactive alkali containing deposits. Under the conditions studied, the presence of a biomass ash deposit aggravated the corrosive propensity of the environment while coal ash lessened it. With regard to predicting the fusion behaviour of different ashes, the standard ash fusion tests proved inadequate for explaining the relationship between high alkali constituents in biomass ash and the expected higher slagging and fouling tendencies. Simultaneous thermal analysis was more useful in assessing the physical & chemical changes taking place in the ash. Prediction of the fuel behaviour using FactSage thermodynamic analysis showed that ash melting commences at much lower temperatures than those predicted from laboratory techniques. This would help to explain the increased risk of deposition and corrosion linked with burning high alkali containing fuels.
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Daniel, Monisha Gnanachandra. "Nanolaminate coatings to improve long-term stability of plasmonic structures in physiological environments." Thesis, Virginia Tech, 2017. http://hdl.handle.net/10919/78280.
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The unprecedented ability of plasmonic metal nano-structures to concentrate light into deep-subwavelength volumes has propelled their use in a vast array of nanophotonics technologies and research endeavors. They are used in sensing, super-resolution imaging, SPP lithography, SPP assisted absorption, SPP-based antennas, light manipulation, etc. To take full advantage of the attractive capabilities of CMOS compatible low-cost plasmonic structures based on Al and Cu, nanolaminate coatings are investigated to improve their long-term stability in corrosive physiological environments. The structures are fabricated using phase-shifting PDMS masks, e-beam deposition, RIE, Atomic Layer Deposition and Rapid Thermal Annealing. An alternate approach using Nanosphere Lithography (NSL) was also investigated. Films were examined using ellipsometry, atomic force microscopy and transmission measurements. Accelerated in-situ tests of Hafnium Oxide/Aluminum Oxide nanolaminate shells in a mildly pH environment with temperatures akin to physiological environments emulated using PBS show greatly enhanced endurance, with stable structures that last for more than one year.<br>Master of Science
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Figgis, Benjamin. "Investigation of PV soiling and condensation in desert environments via outdoor microscopy." Thesis, Strasbourg, 2018. http://www.theses.fr/2018STRAD006/document.
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La salissure des modules photovoltaïques (PV) dégrade grandement leurs performances dans les environnements désertiques. Les études précédentes en extérieur ont tendance à trouver de faibles corrélations entre les taux de salissure et les paramètres météorologiques. On pensait que l'une des raisons était le long intervalle de mesure - jours ou semaines - des techniques traditionnelles de mesure des salissures sur le terrain. Dans la présente étude, un «microscope de souillure extérieur» (OSM) a été développé pour mesurer le dépôt et le détachement de particules de poussière individuelles, toutes les 10 minutes, dans des conditions extérieures, de jour comme de nuit. En utilisant une paire d'OSM graissés et non graissés, il était en outre possible de séparer les salissures en trois vitesses de flux de poussière de composants - dépôt, rebondissement immédiat et remise en suspension retardée. Les OSM ont été utilisés pour mesurer les taux de flux dans des expériences sur le terrain à Doha, au Qatar. La nouvelle méthode a révélé des effets explicatifs de paramètres environnementaux qui avaient auparavant été obscurcis par de longs intervalles de mesure des salissures et des taux de flux de poussière confondus. L'OSM pouvait également mesurer l'apparition et la croissance de gouttelettes de condensation microscopiques dans des conditions de terrain et de laboratoire. De telles expériences, ainsi que des mesures isothermes et des analyses de composition, ont démontré que la condensation sur les surfaces sales au terrain d’études était fortement influencée par la présence de matière hygroscopique dans la poussière autre que NaCl. En raison de cette matière, la condensation microscopique peut persister à la surface même si elle est bien supérieure à la température du point de rosée. Les résultats de l'étude suggèrent que la souillure des modules photovoltaïques pourrait être atténuée en tirant parti des variations naturelles des conditions météorologiques au cours de la journée<br>Soiling of photovoltaic (PV) modules greatly degrades their performance in desert environments. Previous field studies have tended to find weak correlations between the soiling rate and weather parameters. It was thought that one reason was the long measurement interval — days or weeks — of conventional field soiling measurement techniques. In the present study, an “outdoor soiling microscope” (OSM) was developed able to measure deposition and detachment of individual dust particles, every 10 minutes, in outdoor conditions, day and night. By using a greased and ungreased pair of OSMs, it was further possible to separate soiling into three component dust flux rates — deposition, immediate rebound, and delayed resuspension. OSMs were used to measure flux rates in field experiments in Doha, Qatar. The novel method revealed explanatory effects of environmental parameters that had previously been obscured by limits of conventional long soiling measurement intervals and confounded dust flux rates. The OSM could also measure the onset and growth of microscopic condensation droplets in field and laboratory settings. Such experiments, along with isotherm measurements and composition analysis, demonstrated that condensation on soiled surfaces at the test site was strongly influenced by the presence of hygroscopic matter in the dust other than NaCl. Because of such matter, microscopic condensation could persist on both hydrophilic and hydrophobic surfaces well above the dew-point temperature. Results of the study suggest that soiling of PV modules might be mitigated by taking advantage of natural time-of-day variations in weather conditions
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Newton, Seth. "Legacy persistent organic pollutants and chemicals of emerging concern in Sweden : from indoor environments to remote areas." Licentiate thesis, Stockholms universitet, Institutionen för tillämpad miljövetenskap (ITM), 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-97094.
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Bulk atmospheric deposition samples were taken every two months for a year in 2009-2010 at two sites in northern Sweden and analyzed for a suite of legacy and emerging persistent organic chemicals including legacy organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs) and novel flame retardants (NFRs). To further investigate the urban occurrence and contribution to remote contamination of flame retardants, indoor air, ventilation system air, and dust were sampled in several microenvironments in Stockholm during the winter of 2012 for analysis of PBDEs, isomer-specific hexabromocyclododecane (HBCDD), and NFRs. Outdoor air and soil samples were also sampled around the same time period for analysis of the same compounds. Five emerging pollutants were detected in atmospheric deposition: the current-use pesticides trifluralin and chlorothalonil; and the NFRs 1,2-dibromo-4-(1,2-dibromoethyl)cyclohexane (TBECH), 1,2-bis(tribromophenoxy)ethane (BTBPE), and Dechlorane Plus (DP). A decrease in the fraction of the anti isomer of DP was observed at the more remote site, indicating isomer-selective degradation or isomerization during long range atmospheric transport. The more remote site also received more total deposition of organic pollutants despite its receiving less precipitation. Although PBDEs and emerging organic pollutants were detected, the bulk of the deposition consisted of PCBs and hexachlorocyclohexanes (HCHs) at both sites. Several NFRs were identified in indoor and ventilation air samples including TBECH, pentabromotoluene (PBT), hexabromobenzene (HBB), 1,2-bis(pentabromodiphenyl)ethane (DBDPE), 2-ethylhexyl-2,3,4,5-tetrabromobenzoate (EHTBB), and bis(2-ethylhexyl)-3,4,5,6-tetrabromo-phthalate (TBPH). There was no significant difference between concentrations of contaminants in ventilation system air and indoor air indicating that the flame retardants included in this study reach the outdoor environment via ventilation systems. Dust and outdoor air samples have only been analyzed for HBCDDs so far. HBCDD concentrations in apartments, offices, and schools were lower than reported concentrations for other countries in similar microenvironments. However, an enrichment of α-HBCDD compared to γ-HBCDD was observed in dust taken from near treated products in stores when compared to dust taken directly from those products. Very low concentrations of HBCDDs were detected in outdoor air.
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Tarvainen, O. (Oili). "Scots pine and its ectomycorrhizal symbionts under chronic low-level urban pollution—responses and restoration." Doctoral thesis, University of Oulu, 2009. http://urn.fi/urn:isbn:9789514260629.
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Abstract
Boreal urban forests are becoming more and more fragmented and, at the same time, are exposed to low-level but long-term nitrogen and sulphur deposition. Natural mid-boreal forests are dominated by few tree and shrub species, while herbs and grasses are rare. Soils in mid-boreal forests are rich in ectomycorrhizal (ECM) fungi, forming a symbiotic relationship with forest trees, which is important for the nutrient cycle especially in nutrient-poor ecosystems.
Aims of this thesis were 1) to study differences between mid-boreal urban and rural forests in composition of macrofungi and structure of plant communities, 2) to explore whether responses of Scots pine seedlings to excess N are mediated via soil or via air, and 3) to study if partial removal of vegetation and humus layer alleviates the adverse effects of excess N on plant and fungal communities, and promotes performance and regeneration of Scots pine in urban forests. The growth responses of seedlings and their mycorrhizal colonization were studied in both field and greenhouse experiments. Peroxidase (POD) activity was used as a root stress indicator.
Urban forests were poor in number of fruiting ECM fungal species, but rich in herbs and grasses in the field layer, as compared to rural forests. These differences were thought to result from changes in soil properties. ECM fungal colonization in Scots pine roots did not respond significantly to high nitrogen load in soil, but high root POD activity indicated changes in root physiology.
ECM macrofungal diversity in urban forests was not markedly increased during a five-year survey after a partial humus removal treatment. On the other hand, fruiting of Cortinarius semisanguineus is a positive response to the treatment. Scots pine seedling emergence was poor due to rapid revegetation at the urban sites, but the treatment promoted both root and shoot growth of planted Scots pine seedlings in urban forests. Decreased root POD activity in Scots pine seedlings in the humus removal treatment possibly indicates lowered root stress.
Soil manipulations may result in a risk of nutrient leakage, and a risk of invasion by non-typical plants. Also, small stand size with high recreation pressure causes a risk for tree regeneration in urban forest stands. These risks need to be considered when planning management of urban coniferous forests.
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Sandberg, Jan. "Corrosion-induced release of zinc and copper in marine environments." Licentiate thesis, Stockholm : Division of corrosion science, Department of materials science end engineering, School of industrial engineering and management, Royal institute of Technology, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4051.
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Newton, Seth. "Occurrence and fate of emerging and legacy flame retardants : from indoor environments to remote areas." Doctoral thesis, Stockholms universitet, Institutionen för miljövetenskap och analytisk kemi, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-116443.
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Persistent organic pollutants (POPs) are toxic chemicals that can be found in various matrices in all corners of the planet, including remote areas such as the Arctic. Several POPs are known and monitored but given the abundance of new chemicals in commerce about which little is known, chemicals that may be new POPs are constantly being screened for. The use of flame retardants, particularly brominated flame retardants (BFRs), has been increasing for decades. PBDEs and HBCDDs are two types of BFRs that have historically been used in large volumes but recently faced legislative restrictions. However, in order to meet fire safety standards, these BFRs have been replaced by a variety of emerging flame retardants (EFRs) about which little is known especially concerning their toxicity, production volumes, and environmental behavior. The main purpose of this thesis was to investigate the occurrence and fate in indoor and outdoor environments of several EFRs and compare them with PBDEs, HBCDDs, and legacy POPs. Several indoor environments in the city of Stockholm, Sweden were sampled for dust, indoor air, and ventilation system air (Paper II). Results from these samples revealed a number of EFRs that humans are exposed to and that are emitted from buildings through ventilation systems. These included DDC-CO, DBE-DBCH, PBT, HBB, EHTBB, and BEH-TEBP. PBDE levels seem to be declining compared to previous studies in Stockholm. Outdoor air and soil were sampled across transects of Stockholm (Paper II) and Birmingham, United Kingdom (Paper III). Results from these samples showed the presence of many of the same EFRs in the outdoor environment that were found in indoor environments. Urban pulses in air were discovered for PBDEs in both cities and for some EFRs in Stockholm, indicating that the cities are sources of EFRs to the outdoor environment. Atmospheric deposition samples were taken at two sites in northern Sweden (Paper I). Three EFRs (DDC-CO, DBE-DBCH, and BTBPE) and two current-use pesticides (trifluralin and chlorothalonil) were identified, indicating these compounds’ potential for long range transport and global contamination. Other legacy POPs such as HCH, PCBs, and PBDEs were measured in the deposition samples as well. The bulk of deposition was comprised of HCH and PCBs with only minor contributions from PBDEs, chlordanes, and emerging compounds. Finally, passive and active air sampling methods were compared for BFRs in offices in Beijing, China. Some EFRs were identified in indoor air from China; however, BDE-209 was the most predominant compound found (Paper IV). Air samples collected with passive samplers generally had measured FR concentrations within a factor of 2-3 of those collected with active samplers. The use of a GFF in the passive samplers resulted in concentrations of particle-bound contaminants such as BDE-209 that were more comparable to those in active samples. The positioning of the PUF in the passive samplers affected the sampling rates for gaseous compounds and particle retention on PUFs was shown to be a large source of uncertainty in passive sampling.<br><p>At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 3: Manuscript. Paper 4: Manuscript.</p><p> </p>
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Esker, Donald Anton. "An Analysis of the Morrison Formation’s Terrestrial Faunal Diversity Across Disparate Environments of Deposition, Including the Aaron Scott Site Dinosaur Quarry in Central Utah." University of Cincinnati / OhioLINK, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1233009882.
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Esker, Donald Anton. "An analysis of the Morrison Formation's Terrestrial Faunal diversity across disparate environments of deposition, including the Aaron Scott Site Dinosaur Quarry in Central Utah." Cincinnati, Ohio : University of Cincinnati, 2009. http://www.ohiolink.edu/etd/view.cgi?acc_num=ucin1233009882.
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Thesis (M.S.)--University of Cincinnati, 2009.<br>Advisors: Glenn Storrs PhD (Committee Chair), Arnold Miller PhD (Committee Member), Carlton Brett PhD (Committee Member), David Meyer PhD (Committee Member). Title from electronic thesis title page (viewed April 25, 2009). Includes abstract. Keywords: vertebrate paleontology; multivariate analysis; Morrison Formation; Jurassic; dinosaurs; Paleobiology Database; paleoecology; Aaron Scott Site; lacustrine; palustrine; sphenodont; sexual dimorphism; geology; Utah; lagerstatten. Includes bibliographical references.
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Marklund, Anneli. "Levels and sources of organophosphorus flame retardants and plasticizers in indoor and outdoor environments." Doctoral thesis, Umeå : Dept. of Chemistry, Environmental Chemistry, Univ, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-640.
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Smith, James Anthony. "Laser diagnostics of a diamond depositing chemical vapour deposition gas-phase environment." Thesis, University of Bristol, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.247541.
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Adomat, Friederike [Verfasser], Eberhard [Akademischer Betreuer] Gischler, and Wolfgang [Akademischer Betreuer] Oschmann. "Holocene evolution of coastal lagoon environments in Belize, Central America : analysis of stratigraphic patterns, mollusk shell concentrations and storm deposition / Friederike Adomat. Gutachter: Eberhard Gischler ; Wolfgang Oschmann." Frankfurt am Main : Universitätsbibliothek Johann Christian Senckenberg, 2016. http://d-nb.info/1098308182/34.
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Zhang, Xian. "Atmospheric corrosion of zinc-aluminum and copper-based alloys in chloride-rich environments : Microstructure, corrosion initiation, patina evolution and metal release." Doctoral thesis, KTH, Yt- och korrosionsvetenskap, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-151180.
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Fundamental understanding of atmospheric corrosion mechanisms requires an in-depth understanding on the dynamic interaction between corrosive constituents and metal/alloy surfaces. This doctoral study comprises field and laboratory investigations that assess atmospheric corrosion and metal release processes for two different groups of alloys exposed in chloride-rich environments. These groups comprise two commercial Zn-Al alloy coatings on steel, Galfan™ (Zn5Al) and Galvalume™ (Zn55Al), and four copper-based alloys (Cu4Sn, Cu15Zn, Cu40Zn and Cu5Zn5Al). In-depth laboratory investigations were conducted to assess the role of chloride deposition and alloy microstructure on the initial corrosion mechanisms and subsequent corrosion product formation. Comparisons were made with long-term field exposures at unsheltered marine conditions in Brest, France. A multitude of surface sensitive and non-destructive analytical methods were adopted for detailed in-situ and ex-situ analysis to assess corrosion product evolution scenarios for the Zn-Al and the Cu-based alloys. Scanning electron microscopy and energy dispersive spectroscopy (SEM/EDS) were employed for morphological investigations and scanning Kelvin probe force microscopy (SKPFM) for nobility distribution measurements and to gain microstructural information. SEM/EDS, infrared reflection-absorption spectroscopy (IRAS), confocal Raman micro-spectroscopy (CRM) and grazing incidence x-ray diffraction (GIXRD) were utilized to gain information on corrosion product formation and possibly their lateral distribution upon field and laboratory exposures. The multi-analytical approach enabled the exploration of the interplay between the microstructure and corrosion initiation and corrosion product evolution. A clear influence of the microstructure on the initial corrosion product formation was preferentially observed in the zinc-rich phase for both the Zn-Al and the Cu-Zn alloys, processes being triggered by microgalvanic effects. Similar corrosion products were identified upon laboratory exposures with chlorides for both the Zn-Al and the Cu-based alloys as observed after short and long term marine exposures at field conditions. For the Zn-Al alloys the sequence includes the initial formation of ZnO, ZnAl2O4 and/or Al2O3 and subsequent formation of Zn6Al2(OH)16CO3·4H2O, and Zn2Al(OH)6Cl·2H2O and/or Zn5(OH)8Cl2·H2O. The patina of Cu sheet consists of two main layers with Cu2O predominating in the inner layer and Cu2(OH)3Cl in the outer layer, and with a discontinuous presence of CuCl in-between. Additional patina constituents of the Cu-based alloys include SnO2, Zn5(OH)6(CO3)2, Zn6Al2(OH)16CO3·4H2O and Al2O3. General scenarios for the evolution of corrosion products are proposed as well as a corrosion product flaking mechanism for some of the Cu-based alloys upon exposure in chloride-rich atmospheres. The tendency for corrosion product flaking was considerably more pronounced on Cu sheet and Cu4Sn compared with Cu15Zn and Cu5Al5Zn. This difference is explained by the initial formation of zinc- and zinc-aluminum hydroxycarbonates Zn5(OH)6(CO3)2 and Zn6Al2(OH)16CO3·4H2O on Cu15Zn and Cu5Al5Zn, corrosion products that delay the formation of CuCl, a precursor of Cu2(OH)3Cl. As a result, the observed volume expansion during transformation of CuCl to Cu2(OH)3Cl, and the concomitant flaking process of corrosion products, was less severe on Cu15Zn and Cu5Al5Zn compared with Cu and Cu4Sn in chloride-rich environments. The results confirm the barrier effect of poorly soluble zinc and zinc-aluminum hydroxycarbonates Zn5(OH)6(CO3)2 and Zn6Al2(OH)16CO3·4H2O, which results in a reduced interaction between chlorides and surfaces of Cu-based alloys, and thereby reduced formation rates of easily flaked off corrosion products. From this process also follows reduced metal release rates from the Zn-Al alloys.<br>Bättre molekylär förståelse för metallers atmosfäriska korrosion kräver en fördjupad kunskap i det dynamiska samspelet mellan atmosfärens korrosiva beståndsdelar och metallytan. Denna doktorsavhandling omfattar laboratorie- och fältundersökningar av korrosions- och metallfrigöringsprocesser av två grupper av legeringar som exponerats i kloridrika atmosfärsmiljöer: två kommersiella Zn-Al beläggningar på stål, Galfan™ (Zn med 5% Al, förkortat Zn5Al) och Galvalume™ (Zn55Al), samt fyra kopparbaserade legeringar (Cu4Sn, Cu15Zn, Cu40Zn och Cu5Zn5Al). Undersökningar har genomförts i renodlade laboratorie-miljöer med för-deponerade NaCl-partiklar i en atmosfär av varierande relativ fuktighet. Syftet har varit att utvärdera betydelsen av kloriders deposition och legeringarnas mikrostruktur på korrosionsmekanismen samt bildandet av korrosionsprodukter. Jämförelser av korrosionsmekanismer har även gjorts efter flerårsexponeringar av samma legeringar i en marin fältmiljö i Brest, Frankrike. Undersökningarna har baserats på ett brett spektrum av analysmetoder för detaljerade studier dels under pågående atmosfärisk korrosion (in-situ), och dels efter avslutad korrosion (ex-situ). Legeringarnas mikrostruktur och tillhörande variation i ädelhet hos olika faser har undersökts med svepelektronmikroskopi och energidispersiv röntgenmikroanalys (SEM/EDS) samt med en variant av atomkraftsmikroskopi (engelska: scanning Kelvin probe force microscopy, SKPFM). Korrosionsprodukternas tillväxt har analyserats in-situ med infraröd reflektions-absorptionsspektroskopi (IRAS), samt morfologi och sammansättning av bildade korrosionsprodukter ex-situ med SEM/EDS, konfokal Raman mikro-spektroskopi (CRM) samt röntgendiffraktion vid strykande ifall (GIXRD). Det multi-analytiska tillvägagångssättet har medfört att det komplexa samspelet mellan de skilda legeringarnas mikrostruktur, korrosionsinitiering och bildandet av korrosionsprodukter kunnat studeras i detalj. En tydlig påverkan av mikrostruktur på det initiala korrosionsförloppet har kunnat påvisas. Korrosionsinitieringen sker företrädesvis i mer zinkrika faser för såväl Zn-Al- som Cu-Zn-legeringar och orsakas av mikro-galvaniska effekter mellan de mer zinkrika, mindre ädla, faserna och omgivande faser. Deponerade NaCl-partiklar påskyndar den lokala korrosionen oberoende av mikrostruktur. Snarlika sekvenser av korrosionsprodukter har kunnat påvisas såväl efter laboratorie- som fältexponeringar. För Zn-Al-legeringar bildas först ZnO, ZnAl2O4 och/eller Al2O3, därefter Zn6Al2(OH)16CO3·4H2O och Zn2Al(OH)6Cl·2H2O och/eller Zn5(OH)8Cl2·H2O. På ren koppar bildas ett inre skikt dominerat av Cu2O, ett mellanskikt av CuCl och ett yttre skikt med i huvudsak Cu2(OH)3Cl. Beroende på legeringstillsats har även SnO2 och Zn5(OH)6(CO3)2 kunnat identifieras. En mekanism för flagning av korrosionsprodukter på kopparbaserade legeringar i kloridrika atmosfärer har utvecklats. Tendensen för flagning har visat sig vara mycket mer uttalad på ren Cu och Cu4Sn än på Cu15Zn och Cu5Al5Zn. Skillnaden kan förklaras med hjälp av det tidiga bildandet av Zn5(OH)6(CO3)2 och Zn6Al2(OH)16CO3·4H2O på Cu15Zn och Cu5Al5Zn som fördröjer bildandet av CuCl, en föregångare till Cu2(OH)3Cl. Därigenom hämmas även den observerade volymexpansionen som sker när CuCl omvandlas till Cu2(OH)3Cl, en process som visar sig vara den egentliga orsaken till att korrosionsprodukterna flagar. Resultaten bekräftar barriäreffekten hos de mer svårlösliga faserna Zn5(OH)6(CO3)2 och Zn6Al2(OH)16CO3·4H2O, vilken dels resulterar i en minskad växelverkan mellan klorider och de legeringsytor där dessa faser kan bildas, och dels i en reducerad metallfrigöringshastighet.<br><p>QC 20140915</p><br>Autocorr, RFSR-CT-2009-00015 Corrosion of heterogeneous metal-metal assemblies in the automotive industry<br>Atmospheric corrosion and environmental metal dispersion from outdoor construction materials
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MacMillan, Douglas C. "Valuing the environmental benefits of reduced acid deposition in the semi-natural environment." Thesis, University of Stirling, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.244698.
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Fulkerson, Mark. "ATMOSPHERIC MERCURY DEPOSITION IN AN URBAN ENVIRONMENT." Doctoral diss., University of Central Florida, 2006. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/2628.
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Atmospheric mercury deposition, known to be a major source of mercury to aquatic and terrestrial environments, was studied at an urban site in Orlando, FL. Precipitation sampling was conducted from September 2003 to May 2006 at a Mercury Deposition Network site located on the University of Central Florida campus. Weekly rainfall and mercury wet deposition data were gathered from this site, which provided the framework of data for this study. Historical mercury wet deposition data from several sites in Florida were used to develop a regression model to predict mercury deposition at any location in Florida. Stormwater runoff from a 2-acre impervious surface at this study area was monitored during the spring and summer of 2005. Runoff water quality was analyzed to characterize mercury dry deposition. Atmospheric monitoring was also conducted during this period to study the interaction of atmospheric constituents on wet and dry deposition patterns. Spatial and seasonal trends for the entire state suggest 80% of Florida's rainfall and mercury deposition occur during the wet season. A strong linear correlation was established between rainfall depth and mercury deposition (R2 = 0.8). Prediction equations for the entire state, for both wet and dry seasons, were strongly correlated with measured data. The results of two unique methods to quantify dry deposition were similar at this site during this study period. Runoff monitored at this site contained significant levels of mercury, primarily in particulate form (58%). The vast majority of particulate mercury was flushed from the surface during storm events, while significant dissolved fractions remained. Runoff mercury concentrations were consistently higher than rainfall mercury, suggesting dry deposition accounted for 22% of total mercury in runoff. Atmospheric monitoring at this location showed gaseous elemental mercury was the dominant form (99.5%) followed by reactive gaseous mercury (0.3%) and particulate mercury (0.2%). Comparison of the contributions of wet and dry deposition suggested 80% of total mercury deposition was wet deposited during this study, while dry deposition accounted for the remaining 20%. Statistical correlations revealed rainfall scavenging of reactive gaseous mercury was the main factor controlling dry deposition.<br>Ph.D.<br>Department of Civil and Environmental Engineering<br>Engineering and Computer Science<br>Civil Engineering
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Redman, Stephen Alan. "Spectroscopic studies of the diamond chemical vapour deposition environment." Thesis, University of Bristol, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.297799.
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Yamaguchi, Seiji. "Development of bio-environment adjusted materials by electrophoretic deposition." Kyoto University, 2008. http://hdl.handle.net/2433/135597.
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Kyoto University (京都大学)<br>0048<br>新制・論文博士<br>博士(エネルギー科学)<br>乙第12164号<br>論エネ博第52号<br>新制||エネ||39(附属図書館)<br>UT51-2007-T891<br>京都大学大学院エネルギー科学研究科エネルギー基礎科学専攻<br>(主査)教授 八尾 健, 教授 吉川 暹, 教授 森井 孝<br>学位規則第4条第2項該当
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Grashion, Anton R. "Computer aided analysis of ancient fluvial depositional environments." Thesis, Staffordshire University, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.241509.
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Kreuger, Jenny. "Pesticides in the environment : atmospheric deposition and transport to surface waters /." Uppsala : Swedish Univ. of Agricultural Sciences (Sveriges lantbruksuniv.), 1999. http://epsilon.slu.se/avh/1999/91-576-5485-9.pdf.
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Böhm, Maraget. "Acid deposition in the Eastern Transvaal Highveld." Master's thesis, University of Cape Town, 1985. http://hdl.handle.net/11427/22012.
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The Transvaal Highveld has one of the largest potentials for air pollution in South Africa. The area around Witbank and Middleburg in the eastern Transvaal Highveld, is highly industrialized with several coal-fired power stations, burning coal dumps and heavy industries. The pollution levels in this area have been the centre of much dispute in recent years, and yet little emphasis has been placed on the severity of atmospheric deposition despite the fact that acid deposition is a major world-wide environmental concern. This study focusses on the chemistry and severity of atmospheric depositions to the south and south-east of the Witbank-Middleburg Power and Industrial Complex. Bulk depositions were sampled at seven sites during the year August 1982 to August 1983 and rain samples covered five sites for four of the six months of the 1983/84 rainy season.
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Butcher, Geoffrey David Hamilton. "The magnetic fabric and depositional environments of loess deposits." Thesis, University of Southampton, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.303506.
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Graniel, tamayo Octavio. "Atomic layer deposition for biosensing applications." Thesis, Montpellier, 2019. http://www.theses.fr/2019MONTS071.
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Le dépôt de couche atomique (ALD) est devenu une technique essentielle de dépôt en phase vapeur de couches minces pour de nombreuses applications. La demande croissante de composants électroniques et de matériaux nanostructurés a fait de gls{ald} l'un des processus de fabrication clés du marché des nanotechnologies.Dans ce travail, nous présentons de nouveaux matériaux nanostructurés pouvant être utilisés comme transducteurs dans des dispositifs à biocapteurs. Ces matériaux ont été préparés en combinant gls{ald} avec des techniques "top-down" et "bottom-up" telles que la lithographie par nanosphère (gls{nsl}), le dépôt physique en phase vapeur (gls{pvd}), la gravure chimie assistée par des métaux (gls{mace}) et électrodéposition.En tant que premier candidat prometteur, des nanofils de silicium (gls{sinws}) recouverts de ZnO par gls{ald} ont été fabriqués. Ces structures 3D sont très attractives pour les applications de biocapteurs optiques en raison de leur activité intense de photoluminescence (gls{pl}) à température ambiante. Dans une première approche, ces nanostructures coe ur/coquille ont été entièrement caractérisées et testées en tant que capteurs possibles pour la détection du peroxyde d’hydrogène, qui est un produit de réaction courant de plusieurs oxydoréductases.De plus, des nanostructures creuses en ZnO semblables à des oursins recouvertes de Au ont été préparées avec une taille contrôlée en combinant NSL, gls{ald}, électrodéposition et évaporation par faisceau d'électrons (gls{ebeam}). L’influence de l’épaisseur du film Au sur les capacités de diffusion Raman (gls{sers}) améliorées en surface des substrats a été étudiée. Les structures optimisées ont été utilisées pour détecter des molécules de thiophénol avec une limite de détection (gls{lod}) de SI{e-8}{Molar}. De plus, l'adénine peut être détectée avec une concentration aussi basse que SI{e-6}{Molar}. L'excellente uniformité et la répétabilité lot par lot des substrats en font d'excellents candidats pour une détection et une biocapture SERS fiables.En outre, un groupe diversifié de nouveaux matériaux présentant des caractéristiques attrayantes qui peuvent être facilement appliqués à la détection, à la catalyse et à la plasmonique est présenté. Des nanoparticules bimétalliques de Pd/Au supportées sur gls{sinws} avec gls{ald} et un remplacement galvanique ont été fabriquées. De plus, des structures ZnO creuses de type urchin avec ZIF-8 par électrodéposition ont été fabriquées pour de possibles applications SERS<br>Atomic layer deposition (gls{ald}) has emerged as an essential vapor deposition technique of thin films for countless applications. The rising demand for electronic components and nanostructured materials has established gls{ald} as one of the key fabrication processes in the nanotechnology market.In this work, novel nanostructured materials that can be used as transducers in biosensor devices are presented. These materials have been prepared by a combination of gls{ald} with top-down and bottom-up techniques such as nanosphere lithography (gls{nsl}), physical vapor deposition (gls{pvd}), metal-assisted chemical etching (gls{mace}), and electrodeposition.As a first promising candidate, silicon nanowires (gls{sinws}) covered with ZnO by gls{ald} were fabricated. These 3D structures are quite attractive for optical biosensing applications thanks to their intense photoluminescence (gls{pl}) activity at room temperature. As a first approach, these core/shell nanostructures were fully characterized and tested as possible sensors for the detection of hydrogen peroxide, which is a common reaction product of several oxidoreductases.In addition, Au-covered hollow urchin-like ZnO nanostructures were prepared with controlled size by combining NSL, gls{ald}, electrodeposition, and electron beam (gls{ebeam}) evaporation. The influence of the Au film thickness on the surface-enhanced Raman scattering (gls{sers}) capabilities of the substrates was investigated. The optimized structures were used to detect thiophenol molecules with a limit of detection (gls{lod}) of SI{e-8}{Molar}. Additionally, adenine can be detected with a concentration as low as SI{e-6}{Molar}. The excellent uniformity and batch-to-batch repeatability of the substrates makes them excellent candidates for reliable SERS sensing and biosensing.Moreover, a miscellaneous group of novel materials with enticing features that can be readily applied in sensing, catalysis, and plasmonics is presented. Bimetallic Pd/Au nanoparticles supported on gls{sinws} with gls{ald} and galvanic replacement were fabricated. Furthermore, hollow urchin-like ZnO structures with ZIF-8 via electrodeposition were fabricated for possible SERS applications
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Beck, Margaret E. "Ceramic deposition and midden formation in Kalinga, Philippines." Diss., The University of Arizona, 2003. http://hdl.handle.net/10150/280257.
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This ethnoarchaeological study addresses refuse disposal and site formation processes in a village setting, focusing on one artifact class (ceramics) and one type of refuse accumulation (middens). Archaeologists have long relied on middens for large artifact samples. Midden ceramics in particular can contribute to studies of household and community composition, activities, status differences, and food-preparation methods, but interpretations often require linking discarded ceramics to their source, if only in a general sense, and assessing the representativeness of the ceramic sample. This case study provides a model for determining midden catchments, illustrates the variables affecting ceramic deposition, and compares midden ceramics to systemic ceramic assemblages. The deposits themselves are also described in detail, linking observed midden formation processes with the resulting physical and chemical properties. Fieldwork was conducted in February-July 2001 in Dalupa, Kalinga Province, the Philippines, as part of the Kalinga Ethnoarchaeological Project. Residents of Dalupa are subsistence rice farmers, and traditional ceramic production continues despite the availability of metal and plastic alternatives. The 71 households in the community participated in household vessel inventories and weekly interviews to track ceramic vessel breakage and general discard patterns. Thirty active middens were identified in Dalupa, occupying roughly nine percent of the residential area. Twenty-eight of these middens were characterized using some or all of the following methods: surface maps, surface transects for artifact recording and collection, systematic cores for depth, pH measurements, excavated test units, and chemical analysis of soil samples. Observations of midden activity and soil profiles in and around Dalupa provide information on cultural and natural disturbance processes. The result is a picture of midden formation and the creation of midden ceramic assemblages in one community.
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Doering, Che. "Measurements of the distribution and behaviour of Beryllium-7 in the natural environment." Thesis, Queensland University of Technology, 2007. https://eprints.qut.edu.au/16513/1/Che_Doering_Thesis.pdf.
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Beryllium-7 is a cosmogenic radionuclide produced in the atmosphere through the spallation of nitrogen and oxygen nuclei by cosmic-ray-produced neutrons and protons. It is carried in the atmosphere attached to aerosols and is deposited on land and ocean surfaces by wet and dry deposition processes. Beryllium-7 decays by electron capture to lithium-7 and has a half-life of approximately 53 days. It is a potentially useful radionuclide for studying different natural processes.
This thesis presents a collection of scientific papers on the occurrence of beryllium-7 in the natural environment, particularly in the Southeast Queensland region of Australia. It shows the results of experimental measurements and discusses their implications. Overall, this thesis contributes to advancing our understanding of the distribution and behaviour of beryllium-7 in the natural environment and provides a foundation for the development of nuclear techniques for the evaluation of environmental problems.
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Doering, Che. "Measurements of the distribution and behaviour of Beryllium-7 in the natural environment." Queensland University of Technology, 2007. http://eprints.qut.edu.au/16513/.
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Beryllium-7 is a cosmogenic radionuclide produced in the atmosphere through the spallation of nitrogen and oxygen nuclei by cosmic-ray-produced neutrons and protons. It is carried in the atmosphere attached to aerosols and is deposited on land and ocean surfaces by wet and dry deposition processes. Beryllium-7 decays by electron capture to lithium-7 and has a half-life of approximately 53 days. It is a potentially useful radionuclide for studying different natural processes. This thesis presents a collection of scientific papers on the occurrence of beryllium-7 in the natural environment, particularly in the Southeast Queensland region of Australia. It shows the results of experimental measurements and discusses their implications. Overall, this thesis contributes to advancing our understanding of the distribution and behaviour of beryllium-7 in the natural environment and provides a foundation for the development of nuclear techniques for the evaluation of environmental problems.
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Falcon-Lang, Howard James. "Carboniferous wildfires : their impact on vegetation, ecology and depositional environments." Thesis, Royal Holloway, University of London, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.300030.
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Senter, Anne Elizabeth. "Wood Export and Deposition Dynamics in Mountain Watersheds." Thesis, University of California, Davis, 2017. http://pqdtopen.proquest.com/#viewpdf?dispub=10260979.
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<p> Wood dynamics that store, transport, break down, and ultimately export wood pieces through watershed networks are key elements of stream complexity and ecosystem health. Efforts to quantify wood processes are advancing rapidly as technological innovations in field data collection, remotely sensed data acquisition, and data analyses become increasingly sophisticated. The ability to extend the temporal and spatial scales of wood data acquisition has been particularly useful to the investigations presented herein. The primary contributions of this dissertation are focused on two aspects of wood dynamics: watershed-scale wood export processes as identified using the depositional environment of a mountain reservoir, and wood deposition mechanisms in a bedrock-dominated mountain river. Three chapters present this work: </p><p> In Chapter 1, continuous video monitoring of wood in transport revealed seasonal and diurnal hydrologic cycle influences on the variable rates at which wood transports. This effort supports the efficacy of utilizing continuous data collection methods for wood transport studies. Annual wood export data were collected via field efforts and aerial image analyses from New Bullards Bar Reservoir on the North Yuba River, Sierra Nevada, California. Examination of data revealed linkages between decadal-scale climatic patterns, large flood events, and episodic wood export quantities. A watershed-specific relation between wood export quantities and annual peak discharge contributes to the notion that peak discharge is a primary control on wood export, and yielded prediction of annual wood export quantities where no data were available. Linkages between seasonality, climatic components, and hydrologic events that exert variable control on watershed scale wood responses are presented as a functional framework. An accompanying conceptual model supports the framework presumption that wood responses are influenced by seasonal variations in Mediterranean-montane climate conditions and accompanying hydrologic responses. </p><p> Chapter 2 contains development of new theory in support of the introduction of multiplicative coefficients, categorized by water year type, that were used to predict wood export quantities via utilization of an existing discharge-based theoretical equation. This new theory was the product of continued investigations into watershed-scale factors in search of explanation of observed variation of wood export rates into New Bullards Bar Reservoir. The gap between known variability and the attribution of wood export to one hydrologic relation continues to be a persistent issue, as the hierarchical and stochastic temporal and spatial nature of wood budget components remain difficult to quantify. The development of “watershed processes” coefficients was specifically focused on a generalized, parsimonious approach using water year type categories, with validation exercises supporting the approach. In dry years, predictions more closely represented observed wood export quantities, whereas the previously derived annual peak discharge relation yielded large over-predictions. Additional data are needed to continue development of these watershed-specific coefficients. This new approach to wood export prediction may be beneficial in regulated river systems for planning purposes, and its efficacy could be tested in other watersheds. </p><p> Chapter 3 presents the results of an investigation into wood deposition mechanisms in a 12.2 km segment of the confined, bedrock-dominated South Yuba River watershed. Inclusion of coarse wood particles in the analyses was essential in recognizing depositional patterns, thus supporting the value of utilizing a wider wood-size range. A near-census data collection effort yielded myriad data, of which topographic wetted width and bed elevation data, developed for an observed 4.5-year flood event, were standardized in 10-m intervals and then univariate and linked values were ordered into landform classifications using decision tree analyses. Digital imagery collected via kite-blimp was mosaicked into a geographic information system and all resolvable wood pieces greater then 2.5 cm in one dimension were delineated and categorized into piece count density classes. Visual imagery was also key in identifying two river corridor terrains: bedrock outcrops and cobble-boulder-vegetation patches. A conceptual model framed an investigation into how topographic variability and structural elements might influence observed wood deposition dynamics. Forage ratio test results that quantified wood piece utilization versus interval availability revealed that high-density wood deposition patterns were most significantly co-located with five discrete bedrock outcrops that dominated small portions of the river corridor in high flow conditions. Topographic variations and cobble-boulder-vegetation patches were found to be subordinate factors in wood deposition patterns. Bedrock outcrops with specific structural components were the primary depositional environments that acted as floodplain extents for coarse wood deposition, with mechanisms such as topographic steering, eddying, trapping, stranding, backwater effects, and lateral roughness features inferred to be responsible for observed wood deposition patterns.</p><p>
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Howsam, Mike. "The role of woodlands in the cycling of polycyclic aromatic hydrocarbons (PAHs) in the environment." Thesis, Lancaster University, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.310455.
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Chan, Matthew Yunho. "Transport, Stability, and Deposition of Gold Nanoparticles in Porous Media." Thesis, Virginia Tech, 2011. http://hdl.handle.net/10919/64177.
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Gold-nanoparticle (AuNP) transport in groundwater is heavily influenced by the intrinsic properties of the nanoparticles and the external parameters of the environment. Batch experimental data indicated that 15 nm AuNP coated by bovine serum albumin (BSA-AuNP) was more stable at high ionic strength compared to citrate-coated AuNP (cit-AuNP) of similar size. It was expected that the stability of these AuNP would be replicated in column studies. Column experiments with varying monovalent and divalent ion concentrations using both types of AuNP yielded breakthrough curves that both adhere and deviate from this hypothesis. BSA-AuNP was found to be more stable relative to cit-AuNP during porous media flow in the presence of increasing concentrations of CaCl2, but the opposite occurred with increasing NaCl concentration. Colloidal filtration theory (CFT) fails to predict and explain this discrepancy. DLVO calculations suggested pore-space destabilization occurred in these experiments that were not accounted by CFT.<br>Master of Science
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Lawrence, Cameron Eoin. "Measurement of 222Rn Exhalation Rates and 210Pb Deposition Rates in a Tropical Environment." Thesis, Queensland University of Technology, 2006. https://eprints.qut.edu.au/16291/1/Cameron_Lawrence_Thesis.pdf.
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This thesis provides the measurements of 222Rn exhalation rates, 210Pb deposition rates and excess 210Pb inventories for locations in and around Ranger Uranium Mine and Jabiru located within Kakadu National Park, Australia. Radon-222 is part of the natural 238U series decay chain and the only gas to be found in the series under normal conditions. Part of the natural redistribution of 222Rn in the environment is a portion exhales from the ground and disperses into the atmosphere. Here it decays via a series of short-lived progeny, that attach themselves to aerosol particles, to the long lived isotope 210Pb (T1/2 = 22.3 y). Attached and unattached 210Pb is removed from the atmosphere through wet and dry deposition and deposited on the surface of the earth, the fraction deposited on soils is gradually transported through the soil and can create a depth profile of 210Pb. Here it decays to the stable isotope 206Pb completing the 238U series.
Measurements of 222Rn exhalation rates and 210Pb deposition rates were performed over complete seasonal cycles, August 2002 - July 2003 and May 2003 - May 2004 respectively. The area is categorised as wet and dry tropics and it experiences two distinct seasonal patterns, a dry season (May-October) with little or no precipitation events and a wet season (December-March) with almost daily precipitation and monsoonal troughs. November and April are regarded as transitional months. As the natural processes of 222Rn exhalation and 210Pb deposition are heavily influenced by soil moisture and precipitation respectively, seasonal variations in the exhalation and deposition rates were expected. It was observed that 222Rn exhalation rates decreased throughout the wet season when the increase in soil moisture retarded exhalation. Lead-210 deposition peaked throughout the wet season as precipitation is the major scavenging process of this isotope from the atmosphere.
Radon-222 is influenced by other parameters such as 226Ra activity concentration and distribution, soil porosity and grain size. With the removal of the influence of soil moisture during the dry season it was possible to examine the effect of these other variables in a more comprehensive manner. This resulted in categorisation of geomorphic landscapes from which the 222Rn exhalation rate to 226Ra activity concentration ratios were similar during the dry season. These results can be extended to estimate dry season 222Rn exhalation rates from tropical locations from a measurement of 226Ra activity concentration.
Through modelling the 210Pb budget on local and regional scales it was observed that there is a net loss of 210Pb from the region, the majority of which occurs during the dry season. This has been attributed to the fact that 210Pb attached to aerosols is transported great distance with the prevailing trade winds created by a Hadley Circulation cell predominant during the dry season (winter) months. By including the influence of factors such as water inundation and natural 210Pb redistribution in the soil wet season budgeting of 210Pb on local and regional scales gave very good results.
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Lawrence, Cameron Eoin. "Measurement of 222Rn Exhalation Rates and 210Pb Deposition Rates in a Tropical Environment." Queensland University of Technology, 2006. http://eprints.qut.edu.au/16291/.
Full textAbstract:
This thesis provides the measurements of 222Rn exhalation rates, 210Pb deposition rates and excess 210Pb inventories for locations in and around Ranger Uranium Mine and Jabiru located within Kakadu National Park, Australia. Radon-222 is part of the natural 238U series decay chain and the only gas to be found in the series under normal conditions. Part of the natural redistribution of 222Rn in the environment is a portion exhales from the ground and disperses into the atmosphere. Here it decays via a series of short-lived progeny, that attach themselves to aerosol particles, to the long lived isotope 210Pb (T1/2 = 22.3 y). Attached and unattached 210Pb is removed from the atmosphere through wet and dry deposition and deposited on the surface of the earth, the fraction deposited on soils is gradually transported through the soil and can create a depth profile of 210Pb. Here it decays to the stable isotope 206Pb completing the 238U series. Measurements of 222Rn exhalation rates and 210Pb deposition rates were performed over complete seasonal cycles, August 2002 - July 2003 and May 2003 - May 2004 respectively. The area is categorised as wet and dry tropics and it experiences two distinct seasonal patterns, a dry season (May-October) with little or no precipitation events and a wet season (December-March) with almost daily precipitation and monsoonal troughs. November and April are regarded as transitional months. As the natural processes of 222Rn exhalation and 210Pb deposition are heavily influenced by soil moisture and precipitation respectively, seasonal variations in the exhalation and deposition rates were expected. It was observed that 222Rn exhalation rates decreased throughout the wet season when the increase in soil moisture retarded exhalation. Lead-210 deposition peaked throughout the wet season as precipitation is the major scavenging process of this isotope from the atmosphere. Radon-222 is influenced by other parameters such as 226Ra activity concentration and distribution, soil porosity and grain size. With the removal of the influence of soil moisture during the dry season it was possible to examine the effect of these other variables in a more comprehensive manner. This resulted in categorisation of geomorphic landscapes from which the 222Rn exhalation rate to 226Ra activity concentration ratios were similar during the dry season. These results can be extended to estimate dry season 222Rn exhalation rates from tropical locations from a measurement of 226Ra activity concentration. Through modelling the 210Pb budget on local and regional scales it was observed that there is a net loss of 210Pb from the region, the majority of which occurs during the dry season. This has been attributed to the fact that 210Pb attached to aerosols is transported great distance with the prevailing trade winds created by a Hadley Circulation cell predominant during the dry season (winter) months. By including the influence of factors such as water inundation and natural 210Pb redistribution in the soil wet season budgeting of 210Pb on local and regional scales gave very good results.
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Priscu, Caius. "Behavior of mine tailings dams under high tailings deposition rates." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape8/PQDD_0024/NQ50240.pdf.
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Lyons, Timothy Williams 1957. "Stratigraphy and depositional environment of the Colina limestone (lower Permian), southeastern Arizona." Thesis, The University of Arizona, 1989. http://hdl.handle.net/10150/558115.
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Dickhudt, Patrick J. "Controls on Erodibility in a Partially Mixed Estuary, York River, Virginia." W&M ScholarWorks, 2008. http://www.vims.edu/library/Theses/Dickhudt08.pdf.
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Cashman, Amanda L. "Depositional environment analysis of the Pennslyvanian, mid-continent Tonkawa sandstone." Thesis, Kansas State University, 2011. http://hdl.handle.net/2097/11997.
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Master of Science<br>Department of Geology<br>Allen W. Archer<br>Hydrocarbon production throughout the continental United States has declined in past decades. New interpretations together with advanced recovery techniques can increase production in older fields. Re-examining these types of underdeveloped resources is a simple and cost effective tool that can be readily used to increase hydrocarbon production throughout the mid-continent.
Pennsylvanian sandstones throughout Oklahoma and Kansas are known for their excellent reservoir qualities. The focus of this study is the upper Pennsylvanian Tonkawa Formation, a sandstone dominated unit. The Tonkawa has been informally correlated to both the Stalnaker and Tonganoxie sandstones in Kansas. Previous publications do not present a unified understanding of the depositional environments that are seen across state borders. The interpretations vary from fluvio-deltaic to marine environments. A cohesive interpretation is necessary to understand paleo-processes and efficiently exploit the reservoir for hydrocarbons.
The study presents a regional analysis covering an eleven county area in northwest Oklahoma. Analysis of core and well log data is used to determine the range of depositional environments of the Tonkawa sandstone. Sedimentary structures, mineral assemblages, and lithologies of selected cores are described and correlated with well log data. With this data, structural isopach maps are constructed using Petra software. Earlier interpretations have relied primarily on well log data, focusing on core data rather than geophysical logs, allowing for a more detailed and accurate interpretation. Analysis of transitional sedimentary sequences, such as the Tonkawa, can be applied to sandstones deposited in similar environments throughout the mid-continent.
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Kerr, Jeremy M. "Environmental Controls on Depositional Patterns of Isolated Carbonate Platforms." Diss., NSUWorks, 2018. https://nsuworks.nova.edu/occ_stuetd/487.
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This dissertation explores the influence of the environment on the lateral spatial patterning of facies in modern isolated carbonate platforms through six studies. The first study describes the creation of a database of benthic habitat and bathymetric maps derived from multispectral satellite imagery and the field data used calibrate and validate the mapping algorithms. The second study develops and assesses a new approach for remotely-deriving water depth from multispectral satellite imagery without the need for ground-truth information. The third study identifies a criterion for distinguishing between facies belts and mosaics and deploys the criterion to investigate the co-occurrence of these arrangements within modern carbonate depositional systems. The fourth study explores the geologic history of an isolated carbonate platform in the Bahamas, Cay Sal Bank, to understand why the lateral spatial pattering observed in this site differs from the patterns observed in neighboring platforms. The fifth study explores the distribution of carbonate facies in relation to wave energy and water depth for two detached ramps in the Red Sea, Ras Al-Qisbah and Al Wajh. The last study investigates the recovery of scleractinian communities along the coasts of two islands in the Galapagos archipelago, Darwin and Wennman (Wolf) Islands, following a large-scale disturbance in the 1980s. Together, these six studies provide new insight into the spatial patterning of facies within modern carbonate depositional systems and the influence of the environment on the observed arrangements.
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Kondziolka, John M. (John Michael). "Feedbacks between flow, vegetation, deposition, and the implications for landscape development." Thesis, Massachusetts Institute of Technology, 2014. http://hdl.handle.net/1721.1/90051.
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Thesis: S.M., Massachusetts Institute of Technology, Department of Civil and Environmental Engineering, 2014.<br>Cataloged from PDF version of thesis.<br>Includes bibliographical references.<br>Flow and sedimentation around patches of vegetation are important to landscape evolution, and a better understanding of these processes would facilitate more effective river restoration and wetlands engineering. In wetlands and channels, patches of vegetation are rarely isolated and neighboring patches influence one another during their development. This patch-to-patch interaction, and its influence on landscape evolution, was examined through laboratory experiment and numerical modeling. In an experimental study, an adjacent pair of emergent vegetation patches were modeled by circular arrays of cylinders. The flow and deposition patterns behind the pair of patches were measured for two stem densities and for different patch separations (gap widths). For all gap widths (A), the velocity on the centerline between the patches (Uc) was elevated to a peak velocity Umax that persisted over a distance L. Although Umax was not a function of [delta], L decreased with decreasing [delta]. Beyond Lj, the patch wakes merged, and Uc decayed to a minimum at a distance Lm. The merging of wakes and associated velocity minimum produced a local maximum in deposition downstream from and on the centerline between the patches. If this secondary region of enhanced deposition promotes new vegetation growth, the increased drag on the centerline could slow velocity between the upstream patch pair, leading to conditions favorable to their merger. The patch-scale interactions documented in the lab were incorporated into a model of vegetation evolution. The initial flow field was solved using a porous media formulation for hydraulic resistance, and the velocity in wake regions was adjusted to match the wake structure measured in the laboratory study. Vegetation growth was added based on a probabilistic growth function linked to the velocity field. The simulations explored the influence of initial plant density (ID) and threshold velocity (TV, the velocity above which no plants can grow) on landscape evolution. Three types of stable landforms occurred: full vegetation coverage, channeled, and sparse. Full vegetation coverage was achieved for ID >/_ 5% when wakes were included, whereas simulations that excluded the influence of wakes rarely reached full coverage. The model highlights the role of flow diversion into bare regions (channels) in the promotion of growth within vegetated regions.<br>by John M. Kondziolka.<br>S.M.