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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.
81

Potential source rocks in the western Kansas petroleum province

Hill, Tyler J. January 1900 (has links)
Master of Science / Department of Geology / Matthew W. Totten / The source of the hydrocarbons in western Kansas has been an ongoing debate for many years. The highly organic-rich Anadarko basin, directly south of western Kansas, has been a very prolific producer for many years. This basin is the most widely accepted source of the oil in Kansas, as it is very deep and thermally mature. The main source rock in this area is the Woodford Shale, a very thick, very organic-rich unit which has been proven to produce many hydrocarbons. Several studies have been done on the oils that are presently in Kansas, suggesting that they can be traced back to the source of the Woodford Shale. The hydrocarbons in the Anadarko basin would have traveled several hundred miles, which would require that the migration mechanism be unusually efficient. An alternate explanation could be that one of the many organic black shales in western Kansas may have sourced this oil. This study examines formations of Cambrian to Permian ages which include organic shales interbedded with several known producing formations. Shales of these ages in other areas have produced thermally mature hydrocarbons, which indicate relatively high temperatures and pressures. Several models suggest that thermal maturity may be reached even with lower temperatures if burial times are longer. The shales in western Kansas were deposited in marine seas, and upon TOC testing, proved to be very organic-rich. Two sets of data were analyzed in this study, with the first from northwestern Kansas, and the second from southwestern Kansas. These two sets were analyzed for TOC, whole-rock analysis, and vitrinite reflectance. The shales analyzed from the first set proved to be thermally immature. Had they been subjected to higher temperatures, then they would have made excellent source rocks. The second set of shales analyzed also proved to be thermally immature with the exception of a few deeper shales, which are closer to being mature source rocks. These shales may have contributed to some of the hydrocarbons currently within Kansas.
82

Reservoir characterization of the Aldrich, Aldrich NE and Keilman North fields, Ness County, Kansas for potential exploration of sub-Mississippian formations

Leis, Jarred A. January 1900 (has links)
Master of Science / Department of Geology / Matthew Totten / Petroleum producing areas within the mid-continent region discovered in the first half of the 1900’s often ignored the potential of deeper horizons once hydrocarbons were discovered in shallower zones. In Ness County, Kansas the deepest horizon typically explored are Mississippian-aged rocks. One of the largest fields in Ness County is the Aldrich Field, first discovered in 1929. The Mississippian in this field contains an active water-drive, which was produced by an “open-hole” completion method. This precluded drilling deeper horizons. Although modern drilling and completion techniques allow drilling through and isolating water-drive reservoirs like the Mississippian, very few deep exploratory wells have been drilled in Ness County. Wells that penetrate sub-Mississippian horizons are typically drilled as disposal wells, along the flanks of the main structure. This study evaluates the potential of several sub-Mississippian formations to be hydrocarbon reservoirs. Drill cuttings from five wells that penetrate these formations were analyzed using a combination of petrographic microscope, Scanning Electron Microscope (SEM), and chemical methods. Reservoir quality porosity was observed in several sub-Mississippian zones. The presence of hydrocarbon staining was observed in the Viola samples of three wells, and the Arbuckle in one well. Staining was confirmed by EDS spectra under the SEM. The results of this study suggest a good potential of zones deeper than normally drilled to contain hydrocarbons in rocks with reservoir quality porosity. These zones were not drill stem tested in the Aldrich field, and structural advantage to these wells might be expected by drilling the apex of the trapping anticline to further evaluate the deeper horizons.
83

Is intravenous magnesium effective in cardiac arrhythmias?

Campbell, G. January 2008 (has links)
Published Article / Magnesium is the second most abundant intracellular cation with many control and regulatory functions. It regulates energy production and utilization and modulates activity of membrane ionic channels. Magnesium has direct control effects on cardiac myocyte ion channels making it useful in certain arrhythmias. Calcium is responsible for pacemaker excitation and for excitation-contraction coupling in myocytes but increased intracellular calcium produces early and late afterdepolarisations initiating arrhythmias. Magnesium regulates calcium channel activity preventing raised intracellular levels. Potassium channel activity is enhanced by magnesium hyperpolarizing the cell reducing arrhythmia generation. Magnesium is effective against long QT Torsade de Pointes. In rapid atrial fibrillation magnesium produces rate control slowing AV nodal conduction. Magnesium prevents digitalis toxicity due to associated hypomagnesemia.
84

Decreased Commuting Time and its Effects on Accessibility and Productivity

Svanberg, Konrad January 2014 (has links)
This thesis analyzes how a decrease in the commuting time affects the region’s productivity and accessibility on the targeted area Jönköping, Vaggeryd and Värnamo. Numerous municipalities that surround the railway, within a one-hour time range have been included to determine whether an investment on the railway is efficient. The potential growth effects and productivity are measured in wages, and the accessibility is measured as population accessibility. The accessibility is calculated with an accessibility measure, also known The Potential of Opportunities. Additionally, the study includes four control variables. Out of these, four of the six variables proved to significantly influence the regions accessibility and productivity whereas multicollinearity is present in the remaining two. The study differentiates from other similar reports in such way that it investigates a brand new area, different municipalities and finally through the control variables that have not been explicitly used for this specific purpose. The investment is shown to have a substantial effect on the municipalities, especially the smaller ones close to the railway. Shorter time distances, better accessibility and increased productivity all contribute to economic growth and agglomeration.
85

Causal effects in mediation analysiswith limited-dependent variables

Schultzberg, Mårten January 2016 (has links)
Mediation is used to separate direct and indirect effects of an exposure variable on anoutcome variable. In this thesis, a mediation model is extended to account for censoredmediator and outcome variable. The two-part framework is used to account for thecensoring. The counterfactual based causal effects of this model are derived. A MonteCarlo study is performed to evaluate the behaviour of the causal effects accounting forcensoring, together with a comparison with methods for estimating the causal effectswithout accounting for censoring. The results of the Monte Carlo study show that theeffects accounting for censoring have substantially smaller bias when censoring is present.The proposed effects also seem to have a low cost with unbiased estimates for samplesizes as small as 100 for the two-part mediator model. In the case of limited mediatorand outcome, sample sizes larger than 300 is required for reliable improvements. A smallsensitivity analysis stresses the need of further development of the two-part models.
86

Comparison of different methods by means of which water holding capacity of soil is determined and the prediction of water holding capacity from soil texture in coarse-textured soil

Howell, C. L. (Carolyn Louise) 12 1900 (has links)
Thesis (MScAgric)--University of Stellenbosch, 2004. / ENGLISH ABSTRACT: Irrigation scheduling is one of the most important cultural practices in irrigated vineyards. Water holding capacity of soil is arguably therefore one of the most important characteristics of a soil as it determines how much water can be made available to the plant. The measurement of water holding capacity of soils is time consuming and costly. In situ determinations are often impractical to determine. For routine determinations, water holding capacity is therefore determined on disturbed samples. Such a method for example is the rubber ring method. A great deal of criticism surrounds this rubber ring method and results are often questioned. The objectives of this study were therefore to determine what the relationship was between undisturbed and disturbed samples and to determine whether compacted samples could give a more accurate representation of the water holding capacity of soil. Soil textural factors influencing the volumetric water content of undisturbed, rubber ring and compacted samples at 5, 10 and 100 kPa were investigated. In addition, soil textural properties influencing water holding capacity of the respective samples between 5 and 100 kPa and 10 and 100 kPa were investigated. The final objective of the study was to develop simple models to predict the volumetric water content and water holding capacity of soil. Undisturbed and disturbed soil samples were taken at various localities to ensure a wide range of textures. Water holding capacity of undisturbed and disturbed samples was determined at ARC Infruitec-Nietvoorbij using the standard air pressure and ceramic plate technique and the routine rubber ring method respectively. Soil samples were also compacted to a bulk density of approximately 1.5 g.cm-3 as a further treatment for determination of water holding capacity using the air pressure and ceramic plate technique. To investigate aspects of soil texture that could possibly influence volumetric water content of the soil, correlations were done between different texture components and volumetric water content of undisturbed, rubber ring and compacted samples at 5, 10 and 100 kPa. In order to determine the effect of texture on water holding capacity of the soil, correlations were drawn between texture components and water holding capacity of undisturbed, rubber ring and compacted samples between matric potential ranges 5 and 100 kPa and 10 and 100 kPa. The results from this study were used to develop models to predict volumetric soil water content and water holding capacity of soils for a range of soils. Volumetric water content of rubber ring samples at 5 kPa was more than the volumetric water content of undisturbed samples at 5 kPa. The volumetric water content of rubber ring samples at 5 kPa and the volumetric water content of undisturbed samples at 5 kPa was correlated by 87%. Volumetric water content of compacted samples at 5 kPa had a 85% degree of correlation with the volumetric water content of undisturbed samples. At 10 kPa, the correlation between volumetric water content determined using rubber ring samples and undisturbed samples was 77%. This was identical to the correlation between volumetric water content of compacted samples at 10 kPa and undisturbed samples. At 100 kPa, most of the rubber ring samples' volumetric water content fell below the 1:1 line of volumetric water content of undisturbed samples. The volumetric water content of all the compacted samples was higher than that of the undisturbed samples. Water holding capacity of all the rubber ring samples between 5 and 100 kPa was greater than the water holding capacity of the undisturbed samples between 5 and 100 kPa. Rubber ring samples therefore generally overestimated the water holding capacity of the soil. The water holding capacity of most of the rubber ring samples between 10 and 100 kPa was greater than the water holding capacity of the undisturbed samples. In contrast, the water holding capacity of compacted samples between 5 and 100 kPa was less than the water holding capacity of undisturbed samples between 5 and 100 kPa. Water holding capacity of compacted samples was therefore underestimated. The results from this study confirmed that the influence of clay and silt content on volumetric water content of undisturbed, rubber ring and compacted samples increased as the suction on the respective samples is increased. The influence of fine sand content on volumetric water content of undisturbed, rubber ring and compacted samples decreased with an increase in matric potential to 100 kPa. Medium sand content of undisturbed, rubber ring and compacted samples had the greatest influence of all the textural components on the volumetric water content of the respective samples at 5 kPa and 10 kPa. Water holding capacity of undisturbed, rubber ring and compacted samples between 5 and 100 kPa was greatly influenced by the fine sand content of the samples. Medium sand content of the samples also had an influence on the water holding capacity thereof. To predict the volumetric water content of undisturbed samples at 5, 10 and 100 kPa, the independent variables were fine sand content, square root of medium sand content and In of medium sand content. In the case of models to predict the volumetric water content of rubber ring samples at 5, 10 and 100 kPa, the same variables were used as independent variables. Additional variables such as silt content, the In of silt content, square root of clay plus silt content and the medium sand content. To predict the volumetric water content of compacted samples at 5, 10 and 100 kPa the terms used were silt content, clay plus silt content, the e-clay plus silt content. medium sand content and the square root of medium sand content. The models to predict volumetric water content of rubber ring samples gave the best correlation with the actual volumetric water content of rubber ring samples. The final models to predict the water holding capacity of all the samples between 5 and 100 kPa and 10 and 100 kPa used only fine and medium sand parameters as independent variables. Soil textural components do play an important role in determining the volumetric water content of undisturbed, rubber ring and compacted samples at 5, 10 and 100 kPa. The magnitude of the water holding capacity between 5 and 100 kPa and 10 and 100 kPa is also influenced by soil texture. The models developed to predict the volumetric water content of samples at 5, 10 and 100 kPa and the magnitude of the water holding capacity between 5 and 100 kPa and 10 and 100 kPa could be very useful. Both time and money can potentially be saved. Models that can be highly recommended are the models generated for the undisturbed samples. These are: At 5 kPa, VWCu = 0.47259 - 0.04712 medium sando.s At 10 kPa, VWCu = 0.41292 - 0.04221 medium sandos At 100 kPa, VWCu = 0.48080 - 0.00254 fine sand - 0.0865 In medium sand Between 5 and 100 kPa, WHCu = -29.523 + 3.394 fine sand Between 10 and 100 kPa, WHCu = -891.794 + 232.326 In fine sand + 38.006 In medium sand / AFRIKAANSE OPSOMMING: Besproeiingskedulering is een van die belangrikste wingerdverbouingspraktyke. Waterhouvermoë bepaal hoeveel water beskikbaar gestel kan word aan die plant en daarom is dit een van die belangrikste eienskappe van 'n grond. Die meting van waterhouvermoë van grond is tydsaam en duur. Boonop is in situ bepalings dikwels onprakties om te bepaal. Waterhouvermoë word dus bepaal op versteurde monsters vir roetine ontledings. 'n Voorbeeld van so 'n metode is die rubberring metode. Daar bestaan groot kritiek teenoor hierdie rubberring metode en resultate word dikwels betwyfel deur die landboubedryf. Die doel van hierdie studie was dus om te bepaal wat die verwantskap is tussen onversteurde monsters en rubberring monsters asook om te bepaal of gekompakteerde monsters 'n meer akkurate aanduiding sou gee as onversteurde monsters van die waterhouvermoë van die grond. Grondtekstuur faktore wat die volumetriese waterinhoud van onversteurde monsters, rubberring monsters en gekompakteerde monsters by 5, 10 and 100 kPa beïnvloed, was ondersoek. Grondtekstuur faktore wat waterhouvermoë van die onderskeie monsters tussen 5 en 100 kPa en tussen 10 en 100 kPa beïnvloed, was ook ondersoek. Die finale doelwit van die studie was om eenvoudige modelle te ontwikkel vir die voorspelling van volumetriese waterinhoud en waterhouvermoë van grond. Onversteurde grond monsters en grond vir versteurde monsters is by verskeie lokaliteite geneem om 'n wye reeks teksture te verkry. Waterhouvermoë van onversteurde monsters is bepaal by LNR Infruitec- Nietvoorbij met die standaard drukplaat tegniek. Waterhouvermoë van versteurde grond is bepaal met die roetine rubberring metode van LNR Infruitec-Nietvoorbij. Grond was ook gekompakteer tot 'n bulkdigtheid van ongeveer 1.5 g.cm-3 en daarna is die waterhouvermoë bepaal by die LNR Infruitec- Nietvoorbij met die standaard drukplaat tegniek. Om aspekte van grondtekstuur, wat moontlik die volumetriese waterinhoud van grond kan beïnvloed te ondersoek, is korrelasies tussen verskeie tekstuur komponente en die volumetriese waterinhoud van onversteurde monsters, rubberring monsters en gekompakteerde monsters by 5, 10 en 100 kPa bepaal. Om te bepaal watter tekstuur komponente waterhouvermoë van die grond kan bepaal, is korrelasies getrek tussen tekstuur komponente en waterhouvermoë van onversteurde monsters, rubberring monsters en gekompakteerde monsters tussen 5 en 100 kPa en tussen 10 en 100 kPa. Die data is verwerk met die SAS uitgawe 6.12 (SAS, 1990) om modelle vir die voorspelling van volumetriese waterinhoud en waterhouvermoë van grond met behulp van maklik kwantifiseerbare grondtekstuur veranderlikes te ontwikkel. Die volumetriese waterinhoud van rubberring monsters by 5 kPa was meer as die volumetriese waterinhoud van onversteurde monsters by 5 kPa. Die volumetriese waterinhoud van rubberring monsters by 5 kPa en die volumetriese waterinhoud van onversteurde monsters by 5 kPa is gekorreleerd met 87%. Die volumetriese waterinhoud van gekompakteerde monsters by 5 kPa het 'n korrelasie van 85% met volumetriese waterinhoud van onversteurde monsters getoon. By 10 kPa, was die graad van korrelasie tussen volumetriese waterinhoud bepaal met rubberring monsters en onversteurde monsters, 77%. Dit was omtrent dieselfde as die graad van korrelasie tussen volumetriese waterinhoud van gekompakteerde monsters en onversteurde monsters by 10 kPa. By 100 kPa het die meeste van die rubberring monsters se volumetriese waterinhoud onderkant die 1:1 lyn van die volumetriese waterinhoud by 100 kPa van al die onversteurde monsters. Die volumetriese waterinhoud van al die gekompakteerde monsters was hoër as die van die onversteurde monsters. Die waterhouvermoë van al die rubberring monsters tussen 5 en 100 kPa was groter as die van die onversteurde monsters tussen 5 en 100 kPa. Die rubberring monsters het dus oor die algemeen die grootte van die waterhouvermoë oorskry. Die waterhouvermoë van die meeste van die rubberring monsters tussen 10 en 100 kPa was groter as die waterhouvermoë van die onversteurde monsters. Die waterhouvermoë van gekompakteerde monsters tussen 5 en 100 kPa was minder as die waterhouvermoë van die onversteurde monsters tussen 5 en 100 kPa. Die waterhouvermoë van gekompakteerde grondmonsters is dus onderskat. Die resultate van hierdie studie het die invloed van klei- en slik- inhoud op die volumetriese waterinhoud van onversteurde monsters, rubberring monsters en gekompakteerde monsters bevestig. Die invloed van klei en sand op die volumetriese waterinhoud van onversteurde monsters, rubberring monsters en gekompakteerde monsters het toegeneem soos die matriks potensiaal op die onderskeie monsters toegeneem het. Die invloed van fynsand op die volumetriese waterinhoud van onversteurde monsters, rubberring monsters en gekompakteerde monsters was die grootste by 5 kPa en het afgeneem tot by 100 kPa. Die mediumsand inhoud van onversteurde monsters, rubberring monsters en gekompakteerde monsters het van al die tekstuur komponente die grootste invloed op die volumetriese waterinhoud van al die monsters by 5 kPa en 10 kPa gehad. Die waterhouvermoë van onversteurde monsters, rubberring monsters en gekompakteerde monsters tussen 5 en 100 kPa is grootliks beinvloed deur die fynsand inhoud van die monsters. Die mediumsand inhoud van die monsters het ook 'n invloed gehad op die waterhouvermoë daarvan. Om die volumetriese waterinhoud van onversteurde monsters by 5, 10 en 100 kPa te voorspel, is onafhanklike veranderlikes soos fynsand inhoud, vierkantswortel van mediumsand inhoud en In van mediumsand inhoud bepaal. In die geval van modelle om die volumetriese waterinhoud van rubberring monsters by 5, 10 en 100 kPa te voorspel, is dieselfde veranderlikes gebruik as onafhanklike veranderlikes. Addisionele veranderlikes soos slik inhoud, In van slik inhoud, die vierkantswortel van die klei plus slik inhoud en die mediumsand inhoud is ook gebruik. Om die volumetriese waterinhoud van gekompakteerde monsters by 5, 10 en 100 kPa te voorspel, is die terme slik inhoud, klei plus slik inhoud, e-klei plus slik inhoud, mediumsand inhoud en vierkantswortel van mediumsand inhoud gebruik. Die modelle om volumetriese waterinhoud van rubberring samples te voorspel het die akkuraatste voorspellings gegee. Die finale modelle, om waterhouvermoë van alle monsters tussen 5 en 100 kPa en tussen 10 en 100 kPa te bepaal, het slegs fyn en mediumsand as onafhanklike veranderlikes gebruik. Grondtekstuur komponente speel dus 'n belangrike rol in die volumetriese waterinhoud van onversteurde monsters, rubberring monsters en gekompakteerde monsters by 5, 10 en 100 kPa. Die grootte van die waterhouvermoë tussen 5 en 100 kPa en tussen 10 en 100 kPa is ook beinvloed deur die grondtekstuur. Die modelle wat ontwikkel is om die volumetriese waterinhoud van monsters by 5, 10 en 100 kPa en die grootte van die waterhouvermoë tussen 5 en 100 kPa en tussen 10 and 100 kPa te voorspel, kan baie waardevol wees. Tyd en geld kan potensieel bespaar word. Die modelle wat hoogs aanbevole is, is die modelle vir onversteurde monsters. Die modele is: By 5 kPa, VWlo = 0.47259 - 0.04712 rnedlumsand?" By 10 kPa, VWlo = 0.41292 - 0.04221 mediumsando.s By 100 kPa, VWlo = 0.48080 - 0.00254 fynsand - 0.0865 In mediumsand Tussen 5 en 100 kPa, WHVo = -29.523 + 3.394 fynsand Tussen 10 en 100 kPa, WHVo = -891.794 + 232.326 In fynsand + 38.006 In mediumsand
87

Solar Potential Assessment : Comparison Using LiDAR Data and PVsyst

Perez Amigo, Laura January 2016 (has links)
Energy consumption is on a permanent rise and it is becoming increasingly concentrated in cities. Hence, cities have to work on saving energy and being more efficient by finding sources with great potential to produce their own energy and implanting the correct policies. Photovoltaics is the renewable energy technology with the higher potential in the urban context and Sweden is highly committed on its investment since it is the less developed renewable source in the country. The aim of the thesis is to compare two methodologies and determine which one is better or gives more relevant information for this kind of studies in order to evaluate how good a solar map is. For doing this, the first step is to create a solar map to have a general idea about the solar potential and to know which roofs are more suitable to install PV systems. This is made with LiDAR data using ArcGIS and SEES software. After that, another study on the quantity of solar power that could be obtained from those roofs will be performed using PVsyst, where it is possible to develop an entire PV system installation and obtain more exhaust results on energy production and shadowing. Four buildings are going to be evaluated, two public ones located in Gävle city centre (Library and Concert House) and two residential ones located in Sätra. Factors such as the optimal tilt, the best azimuth angle and the distance between panel rows are dimensioned in order to reduce shading loss and improve the performance ratio of the system in PVsyst. The final system is defined with 10° tilt, south orientation (0° azimuth), 1.5meters distance between rows and modules in strings of 9 panels connected in series for the four buildings. The simulated production from the best alternative is compared with the solar map results. Since the solar map contains information about total yearly irradiation, the energy production is obtained by means of visual exploration of the results combined with simple calculations that include GCR and system efficiency. The results show that a solar map is a reliable tool to obtain a general estimation of the solar potential in buildings but it is necessary to first identify its limitations and be able to filter the results. On the other hand, PVsyst software allows making several simulations and eases to obtain a PV system in a building or structure with detailed results of the system components. It can be concluded that since the PVsyst only allows to work with specific buildings or structures, a solar map permits big amounts of data calculations. It can be said that a solar map takes part in the process of obtaining a pre-project and the PVsyst is used in the project when a real installation is sized. Nevertheless, both methods are found to be reliable and suitable for solar potential assessment works since the results obtained match.
88

Quantum fluctuations during inflation and the development of large scale structure

Roberts, David Gawaine January 1997 (has links)
No description available.
89

Photodissociation dynamics of small atmospherically important molecules

Mordaunt, David H. January 1994 (has links)
No description available.
90

Electrode measurement on the net charge on muscle proteins

Bryson, Elzbieta Anna January 1997 (has links)
No description available.

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