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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
241

Assessing hydrologic impact of climate change in the Kou Basin

Sankofi, Ruth 11 1900 (has links)
One of the key areas of climate change impacts is the water resources. Surface water has been compromised by climate change, and so has groundwater. Sub-Saharan Africa has been one of the major sufferers of climate change since the early 70s. The limitations of current global climate models in the prediction of the future climate over the continent have been a source of research challenges in the last decade. Over the decades, West Africa and the Sahel region have been subjected to major droughts and recurrent dry spells. While most studies in the region have tackled climate change effects on surface water and agriculture, a few have highlighted its effects on groundwater. This study investigates climate change impacts on both surface and groundwater in the Kou basin in Burkina Faso. The Kou River and its tributaries have experienced depletion over the last decades. Therefore, it has become necessary to investigate the deficit of the river flow and how the groundwater that forms the springs that feed the rivers is affected by climate change. The study resorts to integrated hydrologic modelling approach using the SWAT surface model and the MODFLOW groundwater model to assess the impact of climate change. Simulations from selected Regional Climate Models (RCMs) are used. Investigations from the RCMs show that the study area is expected to be drier with less precipitation and higher temperatures. Furthermore, the SWAT model results show that as rainfall reduces, future stream flows also significantly decrease. Results from the MODFLOW model also follow the trend of the SWAT model. Groundwater levels are declining whatever the RCM outputs used. Overall, all the models predicted a severely decreasing trend in surface and groundwater in the Kou basin. The study results will be particularly useful for water resources managers in the Kou River basin. / Thesis / Master of Science (MSc)
242

Meals in Motion: Ceramic and Botanical Investigations of Foodways in the Late Formative and Tiwanaku IV/V, Lake Titicaca Basin, Bolivia

Reilly, Sophie E. January 2017 (has links)
In Andean South America, archaeological research demonstrates that rituals surrounding the consumption of food and drink have long played an important part in building relationships between individuals, families, and communities. This thesis focuses on foodways in the Late Formative (200BC-AD475) and Tiwanaku (475-1000AD) phases of the Lake Titicaca basin in highland Bolivia. I pair ceramic and botanical datasets from three assemblages: Late Formative contexts from Kala Uyuni (southern Titicaca Basin) and Challapata (eastern Titicaca Basin), and a Tiwanaku phase burial at Chiripa (southern Titicaca Basin). The goals of this thesis are to: identify microbotanical plant remains of foods associated with ceramic vessels, consider how these inform archaeological understandings of Titicaca Basin foodways, and evaluate whether studying plant residues from ceramic vessels is an effective method to study foodways. Phytoliths and starch grains recovered from Challapata and Chiripa included remains of both local and non-local plants, while the Chiripa ceramic assemblage included non-local ceramic styles. These results offer new evidence for exchange between highland and lowland sites. Both local and non-local plant remains were recovered in public spaces where ceremonies may have taken place. While non-local goods may have been desirable and special because they were difficult to obtain, results of this thesis suggest that local plants may have been just as symbolically important. Overall, results indicate that pairing ceramic and botanical datasets can enable a richer understanding of foodways. / Thesis / Master of Arts (MA)
243

Reconstructing the Thermal History of the Morondava Basin, Madagascar During Gondwana Breakup: A Detrital Zircon (U-Th)/He and U-Pb Study

Schetselaar, Willem Martijn 20 September 2022 (has links)
The Morondava Basin is one of three Phanerozoic rift basins bordering the western coast of Madagascar. Sediments were first deposited in this basin during the initial stages of breakup of Gondwana in the Permian, sourced from the adjacent Precambrian basement terranes. Gondwana breakup resulted in several stages of subsidence, tilting, and uplift of Madagascar, the thermal history of which is recorded within the strata of the Morondava Basin. We have applied U-Pb detrital zircon techniques to investigating the sedimentation and transport patterns of Jurassic and Cretaceous strata. In order to reconstruct the thermal history of the Morondava Basin throughout the stages of rift basin development we have applied modelling of (U-Th)/He thermochronology data. Our models show a protracted cooling history influenced by multiple stages of uplift and subsidence occurring differentially across the basin. A furthered understanding of the Morondava Basin with respect to its development during Gondwana breakup has implications for oil exploration in the region.
244

The Effects of Basin Slope and Boundary Friction on the Character and Plunge Location of Hyperpycnal Flows Entering a Laterally Unbounded Basin

Bhide, Shantanu Vidyadhar 19 June 2019 (has links)
This thesis focuses on the behaviour of hyperpycnal plumes in river mouth discharges. The plunging of high density flows in two dimensional channels has been extensively studied before. A fundamental assumption in these studies is that the flow is laterally confined. These studies allow the flow to plunge only in two directions, the horizontal x-direction and the vertical z-direction. The goal of this study is to determine if there is observable plunging of hyperpycnal flows in the lateral y-direction, i.e. lateral spreading, in a three dimensional domain and to find out the parameters influencing the lateral spread. Previous studies conducted in laterally confined channels suggest that hyperpycnal flows plunge when the flow reaches a densimetric Froude number of unity. This study attempts to find the densimetric Froude number at hyperpycnal plunging in a three dimensional domain and if it is influenced by the factors that also influence the spread. This study also analyzes whether the cross-shore location for plunging changes when lateral spreading is accounted for, relative to a two dimensional analysis and if the plunging is limited to flow reaching a certain depth. This was accomplished through a series of experimental simulations on a hypothetical river mouth domain using Delft-3D, a hydrodynamic modeling software. Three parameters viz. the bottom slope of the receiving basin, the bottom friction and the density difference between inflow and ambient liquid were varied to test their influence on the plume spread rate. / Master of Science / It is crucial for researchers to have the expertise in modeling flow processes that develop in oceans, lakes and reservoirs in order to aid efforts in improving conditions for water quality within such domains. Hyperpycnal flows, also commonly known as high density flows are among one of the the less studied phenomenon in this discipline. This phenomenon occurs when a river carrying water with high density flows into an ocean, lake or a reservoir containing water with a lower density. Such flow regimes cause the inflow to submerge and sink to the bottom (plunge) and form a density current on the bed of the receiving basin. Studying density flows is important to model the transport of sediments, dissolved solids or pollutants. This study aims to improve the existing understanding of hyperpycnal plumes, their plunge location and spread in a three dimensional domain. For this, a simulation software Delft3D was used to build a model that is representative of the system and closely resembles the flow processes taking place in the aforementioned domains. Simulations were then run to collect data on how factors like the initial flow conditions (∆ρ), the basin slope (S) and friction (Chézy coefficient, Cz) have an impact on the phenomenon. This data was then compared to previous analyses to show the difference in plume behaviour and prediction of plunging. This study serves as a stepping stone in the ultimate goal of developing a prediction model for hyperpycnal plumes, indicating that Delft3D is a promising tool for analyzing such phenomenon.
245

Stratigraphic Analysis and Reservoir Characterization of the Late Oligocene-Early Miocene, Upper Yenimuhacir Group, Thrace Basin, Turkey

Diyarbakirli, Ali Can 09 December 2016 (has links)
The Thrace Basin, NW Turkey, is one of the most important basins in Turkey in terms of hydrocarbon potential. Previous studies, starting in the 1930s, focused on tectonics, basin evolution, sedimentation and stratigraphy, depositional systems, and hydrocarbon potential. Eocene turbiditic sandstones and reefal limestones, and Oligocene deltaic sandstones are the major reservoir targets in the basin today. The focus of this research is the Upper Oligocene deltaic sandstones, namely the Danismen and Osmancik formations, which contain potential hydrocarbon reservoirs. The aims of research were to develop a better understanding of the geometric configuration of the Oligocene strata and to identify potential reservoirs within the study area. Accordingly, the geometric configurations of the strata were delineated using 3D seismic reflection data whereas petro-physical properties of the target formations were determined using wireline logs from three wells. A right-lateral strike slip or reverse fault system and associated NW-SE trending asymmetric fold extend across the study area. Both the fault system and the fold are truncated beneath the Miocene unconformity and are thus dated as late Oligocene to early Miocene in age. The Miocene unconformity forms a stratigraphic trap whereas the fault system and associated fold construct a NW-SE trending structural trap. Hydrocarbon-bearing, five main clean sandstone (shale volume less than %10) intervals were identified using wireline logs and evaluated as potential targets. Hydrocarbon concentrations increase through the fold structure. Thus, the fault system and the associated asymmetric fold were the main factors that affected the zonal distribution of hydrocarbons in the study area. / Master of Science / Thrace Basin, northwest part of Turkey, is one of the most important basins in Turkey in terms of oil and gas potential. Previous studies started in1930s and included studies on the geology of the basin. Major reservoir targets in the basin today are Eocene turbiditic sandstones and reefal limestones, and Oligocene deltaic sandstones. This study focuses on the Oligocene deltaic sandstones of the Danismen and Osmancik formations, which are significant in terms of the oil and gas potential in the basin. The main purpose of this thesis is to evaluate the geometric configurations of these two formations and to identify potential reservoirs within the study area. For this purpose, geometric representation of the study area was generated by mapping the formations with the help of 3D seismic data. Reservoir characteristics related to physical properties were determined by utilizing the data obtained from three wells within the study area. As a result, potential reservoir zones are discovered mainly in the Danismen Formation, which can further be incorporated with exploration activities in the basin.
246

Analysis of subsidence and thermal history in the Sabinas Basin, northeasern Mexico

Cuevas Leree, Juan Antonio January 1985 (has links)
No description available.
247

Η τεκτονο-στρωματογραφική εξέλιξη της ΝΑ Μεσογείου, με έμφαση στη λεκάνη του Ηροδότου, στην κατεύθυνση ανάπτυξης πεδίων υδρογονανθράκων

Ηλία, Χρίστος 11 July 2013 (has links)
Η Μεσόγειος θάλασσα είναι μια κλειστή θάλασσα που μπορεί να χωριστεί σε δυτικό και ανατολικό τμήμα. Η ανατολική Μεσόγειος είναι μεγαλύτερη σε μέγεθος από την δυτική και παρουσιάζει έντονο γεωλογικό ενδιαφέρον σε διάφορους τομείς. Συγκεκριμένα η νοτιοανατολική Μεσόγειος με την παρουσία της Μεσογειακής ράχης, της Λεκάνης Λεβαντίνης, του αβυσσικού πεδίου του Ηροδότου, του κώνου του Νείλου και του ηπειρωτικού μπλοκ του Ερατοσθένη αποτελεί ένα μεγάλο πεδίο ερευνών. Ένας τομέας ερευνών που τα τελευταία χρόνια παρουσιάζει μια έξαρση είναι η ύπαρξη πεδίων υδρογονανθράκων στην περιοχή. Το μεγαλύτερο ενδιαφέρον εστιάζεται στη γεωλογική εξέλιξη δυο λεκανών, της Λεβαντίνης νοτιοανατολικά της Κύπρου και του Ηροδότου νοτιοδυτικά της Κύπρου. Οι δυο αυτές λεκάνες σχηματίστηκαν την ίδια γεωλογική περίοδο ως λεκάνες προχώρας λόγω της καταβύθισης της Αφρικανικής πλάκας κάτω από την Ευρασία. Φιλοξενούν το ίδιο περίπου πάχος ιζημάτων όπως και ίδιους τύπους ιζημάτων. Έχουν διαφορετική γεωμετρία με την λεκάνη του Ηροδότου να είναι βαθύτερη και διπλάσια σε έκταση από την λεκάνη της Λεβαντίνης. Για την λεκάνη της Λεβαντίνης υπάρχουν αρκετά στοιχεία για την στρωματογραφία της, και τη δυνατότητα της να αναπτύξει πεδία υδρογονανθράκων, καθώς και πιστοποιημένα αποθέματα πετρελαίου και φυσικού αερίου. Μέσω αυτών των στοιχείων και γνωρίζοντας ότι η λεκάνη Ηροδότου έχει ίδια ηλικία σχηματισμού συγκρίναμε τις δυο λεκάνες όσον αφορά την παλαιογεωγραφική τους εξέλιξη και την στρωματογραφία τους με σκοπό να εκτιμήσουμε τα αποθέματα που μπορεί να φιλοξενεί η λεκάνη του Ηροδότου. Σύγχρονα λαμβάνουμε υπόψη και το ρόλο που διαδραματίζουν στην εξέλιξη των λεκανών αλλά και της ευρύτερης περιοχής, το ηπειρωτικό μπλοκ του Ερατοσθένη και ο κώνος του Νείλου Παρουσιάζονται επίσης σεισμικά δεδομένα στα οποία φαίνονται άμεσοι δείκτες υδρογονανθράκων DHI (Direct Hydrocarbons Indicators) αλλά και άλλα στοιχεία που αφορούν την εξέλιξη των λεκανών. Αυτοί οι δείκτες συνδέονται άμεσα με σημεία στα οποία υπάρχουν διαφυγές υδρογονανθράκων, όπου πιθανά να υπάρχουν πεδία υδρογονανθράκων. Επίσης αναφέρεται ποια πρέπει να είναι τα κριτήρια ούτως ώστε να αναπτυχθούν υδρογονάνθρακες. Τέλος παρουσιάζεται ένας συγκεντρωτικός πίνακας με όλα τα συγκριτικά στοιχεία των δυο λεκανών, που μας δείχνει τα πιστοποιημένα στοιχεία της λεκάνης της Λεβαντίνης και τις εκτιμήσεις για την λεκάνη του Ηροδότου μέσα από την σύγκριση της με τη λεκάνη Λεβαντίνης. / The Mediterranean Sea is an close sea that can be divided into western and eastern part. The Eastern Mediterranean is larger in size than the west and has a big geological interest in various fields. Specifically, the southeastern Mediterranean in the presence of the Mediterranean ridge, the Levantine basin, the Herodotus abyssal plain, the Nile cone and the Eratosthenes continental block, is a large field of investigation. One of the main interesting topics is the genesis and the development of hydrocarbon fields in the area. The major focus is on the palaeogeographic evolution of two major basins, such as Levantine basin and Herodotus basin. These two basins were formed in the same geological period as foreland basins due to subduction of the African plate beneath Eurasia. Accommodate approximately the same sediment thickness and the same sediment types. They have different geometry with Herodotus basin is deeper and doubles in size from the Levantine basin. For the Levantine basin there is enough evidence for the stratigraphy, and the ability to develop oil fields and they are certified reserves of petroleum and natural gas. Through these elements and knowing that Herodotus basin formed in the same age we compared the palaeogeographic evolution and stratigraphy of the two basins with a view to assess the stocks that can accommodate the Herodotus basin. At the same time we take into account the role they played in the evolution of the basins, the Eratosthenes continental block and the Nile cone. Seismic data are also presented which show direct hydrocarbon indicators DHI (Direct Hydrocarbons Indicators) and other data concerning the evolution of the two basins. These indicators are directly linked to places where there are leaks of hydrocarbons, which are thought to be hydrocarbon fields. Finally we present a table summarizing all the comparisons of the two basins, which shows us the certified data of the Levantine basin and the estimated oil and gas reserves of Herodotus basin through the comparison of the Levantine basin.
248

Characteristics of pools used by adult summer steelhead (Oncorhynchus mykiss) in the Steamboat Creek Basin, North Umpqua River, Oregon

Baigun, Claudio Rafael Mariano 14 November 1994 (has links)
This study examined features of deep pool (>0.8 m mean depth) used by adult summer steelhead in Steamboat Creek (1991-1992). Steamboat Creek had a heterogenous thermal profile, with some segments exceeding preferred temperature of steelhead. Deep pools were scarce (4% of the total habitat units) and 39% of them were identified as cool pools (mean bottom water temperature [less than or equal to] 19°C). Adult summer steelhead were found primarily in deep pools, avoiding other habitats (glides, riffles) and even cold but shallow tributary junctions. Use of odds ratio showed that use of cool pools use was estimated to be 11 times greater than the odds of the use of warm pools (P <0.001). Discriminant analysis identified mean bottom pool water temperature, riparian forest at the pool bank, proportion of large boulders, maximum length and mean depth as the best subset of variables that accounted for differences between pools occupied and not occupied by adult steelhead. A total of 69% of the variation was explained by differences in used and not used groups. Classification accuracy was 89%. Canton Creek, a tributary of Steamboat Creek, were tested as validation site for the derived model, observing that the classification function performed moderately, achieving a hit-ratio of 0.7. Results of the study showed that, since bottom pool temperature was a major factor but other ecological factors were also relevant, an integrated framework would be required in determining pool used by this species. Moderate success of the predictive model suggests that managers will want to check it before applying in other basins. / Graduation date: 1995
249

An institutional and economic assessment of water reuse in the Tucson Basin

Lieuwen, Andrew L. January 1989 (has links)
With groundwater resources becoming less available in the physical, economic, and legal senses, water reuse is rapidly gaining momentum in the arid West. An institutional assessment of water reuse in the Tucson Basin in Arizona indicates that despite institutional changes encouraging the substitution of effluent for native groundwater, many opportunities for water reuse are precluded by existing water rights arrangements and insufficient economic incentives. An economic assessment compares potential benefits and costs of implementing water reuse plans for the Tucson area with potential benefits and costs of alternative water-supply scenarios in which similar quantities of water are provided from other sources. Alternative water sources include pumping native groundwater, "reallocating" water saved through reduction in low value water uses, and importing surface water and groundwater from other basins. The results of this study indicate that at the present time, there is no convincing economic justification for increasing water reuse as planned by the City of Tucson. Not only are reduction in use and importation alternatives less costly to implement than increasing effluent use, they also save more groundwater. The results of the economic assessment indicate that the citizenry of the Tucson Basin would be better served if planned increases in the use of effluent in the Tucson metropolitan area were postponed until the costs become more competitive with the costs of alternatives.
250

Fast Stochastic Global Optimization Methods and Their Applications to Cluster Crystallization and Protein Folding

Zhan, Lixin January 2005 (has links)
Two global optimization methods are proposed in this thesis. They are the multicanonical basin hopping (MUBH) method and the basin paving (BP) method. <br /><br /> The MUBH method combines the basin hopping (BH) method, which can be used to efficiently map out an energy landscape associated with local minima, with the multicanonical Monte Carlo (MUCA) method, which encourages the system to move out of energy traps during the computation. It is found to be more efficient than the original BH method when applied to the Lennard-Jones systems containing 150-185 particles. <br /><br /> The asynchronous multicanonical basin hopping (AMUBH) method, a parallelization of the MUBH method, is also implemented using the message passing interface (MPI) to take advantage of the full usage of multiprocessors in either a homogeneous or a heterogeneous computational environment. AMUBH, MUBH and BH are used together to find the global minimum structures for Co nanoclusters with system size <em>N</em>&le;200. <br /><br /> The BP method is based on the BH method and the idea of the energy landscape paving (ELP) strategy. In comparison with the acceptance scheme of the ELP method, moving towards the low energy region is enhanced and no low energy configuration may be missed during the simulation. The applications to both the pentapeptide Met-enkephalin and the villin subdomain HP-36 locate new configurations having energies lower than those determined previously. <br /><br /> The MUBH, BP and BH methods are further employed to search for the global minimum structures of several proteins/peptides using the ECEPP/2 and ECEPP/3 force fields. These two force fields may produce global minima with different structures. The present study indicates that the global minimum determination from ECEPP/3 prefers helical structures. Also discussed in this thesis is the effect of the environment on the formation of beta hairpins.

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