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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.
1

Analytical Analysis of Groundwater Availability in Oktibbeha County, Mississippi

Crabtree, Brandon 12 August 2016 (has links)
Oktibbeha County, Mississippi depends on the Gordo Formation for fresh water. This formation has never been analyzed as to its limits as the exclusive groundwater source for Oktibbeha County. The last extensive groundwater study in this area was done in 1965 and included the surrounding counties while focusing on the larger cities in that area. This project studied the aquifer systems within the county and determined the groundwater resources for the county with its growing population. Groundwater was analyzed for future usability as a public supply. Potentiometric surface maps were also updated in the area to reflect current groundwater levels and projected groundwater levels. Updated cross sections were also created for a more detailed understanding of the geologic units and hydraulic properties of the aquifer systems in the area.
2

Eine erweiterte Theis-Lösung: Berechnung und Implementierung einer Lösung der transienten Grundwassergleichung unter Berücksichtigung von Heterogenität im Coarse-Graining-Modell

Müller, Sebastian 20 October 2017 (has links)
Die vorliegende Arbeit behandelt die Modellierung von Fließprozessen in Grundwasserleitern. Grundlage dafür ist die Grundwassergleichung, welche diese Prozesse mathematisch beschreibt. Die wichtigste hydraulische Eigenschaft von Untergründen ist hierbei die hydraulische Leitfähigkeit, welche die Fließgeschwindigkeit des Grundwassers angibt. Da man die Verteilung der Leitfähigkeit in einem betrachten Wasserleiter aber durch das Fehlen von Informationen nicht vollständig bestimmen kann, ist man auf vereinfachende Modelle und Versuchsszenarien angewiesen. In der Vergangenheit haben sich zur Untersuchung von Böden sogenannte Pumpversuche etabliert, wobei ein Brunnen gebohrt wird, welcher den Grundwasserleiter vollständig durchteuft und an dem mit konstanter Rate Wasser aus dem Boden gepumpt wird. Parallel beobachtet man an einem oder mehreren Referenzbrunnen die sich verändernde hydraulische Druckhöhe. Aus diesen Daten möchte man Informationen über den betrachteten Boden gewinnen. Dazu braucht es gewisse Modellfunktionen, welche für fest definierte Standardsituationen das Grundwasserverhalten beschreiben. Eine Möglichkeit, Böden zu klassifizieren ist es, die heterogene Struktur der Leitfähigkeit durch log-normal verteilte Zufallsgrößen zu modellieren. Dabei beschränkt man sich auf den Mittelwert, die Varianz und die Korrelationslänge dieser Verteilungen. Das hier zugrunde liegende Coarse-Graining-Modell generiert zu diesen Parametern eine effektive Leitfähigkeitsverteilung, welche nur vom radialen Abstand zum Pumpbrunnen abhängt. Damit wird die Grundwassergleichung zu einer radialsymmetrischen parabolischen Differentialgleichung. Zu dieser Differentialgleichung wurde in der vorliegenden Arbeit ein Lösungsalgorithmus entwickelt und implementiert sowie anschließend gegen verschiedene Parametereingaben getestet.
3

Evaluation of groundwater flow theories and aquifer parameters estimation

Xiao, Liang January 2014 (has links)
Philosophiae Doctor - PhD / This thesis deals with some fundamental aspects of groundwater models. Deterministic mathematical models of groundwater are usually used to simulate flow and transport processes in aquifer systems by means of partial differential equations. Analytical solutions for the deterministic mathematical models of the Theis problem and the transient confined-unconfined flow in a confined aquifer are investigated in the thesis. The Theis equation is a most commonly applied solution for the deterministic mathematical model of the Theis problem. In the thesis, a most simplified similarity transformation method for derivation of the Theis equation is proposed by using the Boltzmann transform. To investigate the transient confined-unconfined flow towards a fully penetrating well in a confined aquifer, a new analytical solution for the deterministic mathematical models of interest is proposed in the thesis. The proposed analytical solution considers a change of hydraulic properties (transmissivity and storativity) during the confined-unconfined conversion. Based on the proposed analytical solution, a practical method to determine distance of the conversion interface from pumping well and diffusivity of the unconfined region is developed by using a constant rate test. Applicability of the proposed analytical solution is demonstrated by a comparison with previous solutions, namely the MP and the Chen models. The results show that the proposed analytical solution can be used to assess the effect of the change of diffusivity on the transient confined-unconfined flow. The MP model is only accepted if the transmissivity during the confined-unconfined conversion is constant. The Chen model, given as a special case of the proposed analytical solution, is limited to the analysis of the transient confined-unconfined flow with a fixed diffusivity. An important application of groundwater models is to estimate parameters, such as hydraulic properties and flow dynamics, of groundwater systems by assessing and analysing field data. For instance, the pumping and the hydrochemistry and environmental tracer tests are two effective ways to obtain such data. To evaluate hydraulic properties of aquifer systems by derivative interpretation of drawdown data from pumping tests, a new diagnostic analysis method is proposed based on a lg-lg drawdown derivative, dlgs/dlgt, and the differentiation algorithm namely Lagrange Interpolation Regression (LIR) in the thesis. Use of a combined plot of dlgs/dlgt and a semi-lg drawdown derivative (ds/dlgt) is made to identify various flow segments during variable discharge tests with infinite conditions, constant rate tests in bounded aquifers and tests involving double-porosity behaviours. These can be applied to further characterize pumped aquifers. Compared to traditional diagnostic analysis method using plot of ds/dlgt alone, the combined drawdown derivative plot possesses certain advantages identified as: (1) the plot of dlgs/dlgt is strikingly sensitive for use in unveiling differences between pumping and its following recovery periods in intermittent variable discharge tests; (2) storativity (S) of pumped aquifers can be evaluated by using the combined plot; and (3) quantitative assessments of double-porosity behaviours can also be achieved. Based on two case studies, advantages and disadvantages of uses of the LIR and other existing differentiation methods in calculations of numerical drawdown derivative are demonstrated in practice. The results suggest that the LIR is a preferred method for numerical differentiation of drawdown data as it can be used to effectively minimise noisy effects. The proposed derivative approach provides hydrologists with an additional tool for characterizing pumped aquifers. Use of hydrochemistry and environmental tracer tests to assess flow dynamics of groundwater systems is demonstrated via a case study in the dolomite aquifer of South Africa. An emphasis is on determining mean residence times (MRTs) of the dolomite aquifer by means of an appropriate box model with time series of 14C values of dissolved inorganic carbon (14C-DIC) and initial 14C activities of spring samples during 1970s and 2010s. To obtain the calibrated 14C MRTs, 13C values of dissolved inorganic carbon (δ13C-DIC) of the spring samples are applied to estimate mineral dissolution in the dolomite aquifer and calculate the initial 14C activities. The results indicate that the spring samples have about 50%-80% initial 14C activities. By using the appropriate box model, the calibrated 14C MRTs of the spring system are given within a range from ≤ 10 to 50 years. Additionally, the flow dynamics, including the recharge source and area, the effect of climate change on the temporal trend of the groundwater MRTs and the groundwater flow circulation, of the dolomitic spring system are also discussed for further possible management interventions in the dolomite aquifer.
4

Shift Rotation Among Correctional Officers as a Source of Perceived Job Related Stress

Ingram, Phyllis 01 January 1986 (has links)
My formal hypothesis for this study is that shift rotation among correctional officers has an effect on correctional officer stress. Although there are many definitions of stress, for the purpose of this study stress is defined as conscious nervous tension. Many authors believe that stress develops from a person's reactions to certain situations that are threatening or exert pressure on them. It is felt that whatever the cause, stress depends not on the outside event but on how one reacts to it. For the purpose of this study, stress was not formally defined to the correctional officers because I was looking for perceptions of stress, or how an officer reacts to certain situations.
5

Muzeum automobilů / Car Museum

Suchý, Jakub January 2019 (has links)
The subject of these Master Thesis is a new building of Cars Museum. The object is located in Telc on street Radkovska, district Jihlava. This locality was chosen for its favorable conditions. In this area, there are lots of enthusiast and supporters of motorism. The nearest commission of veterans is around 50 km far. This museum is also meaning to improve a network of a commission of veterans. Telc is a beautiful historic city, which is an ideal choice for a museum of veterans. The building is divided into 3 imaginary sectors. The first one is an administrative part, which has two above-ground floors. In the first floor, there is educative room to familiarize guests with the history of vehicles, entry hall with reception, hygienic facilities for guests and base for staff and operations of the museum. In the second floor, there are offices for the museum, the commission of veterans, meeting room, storeroom, gaming-room, and daily room. The second part is the exhibition area. The third part is workshops and a base to remove operating fluids from cars. The investor is a passionate collector of historic vehicles and wants to share his collection with the public.
6

Grain-Size and Permeability of Sediments Within the Hyporheic Zone at the Theis Environmental Monitoring and Modeling Site, Great Miami River and Buried Valley Aquifer, Southwest Ohio, USA

Cornett, Timothy Wayne January 2021 (has links)
No description available.

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