• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 31
  • 9
  • 4
  • 4
  • 2
  • 1
  • Tagged with
  • 75
  • 42
  • 14
  • 14
  • 14
  • 11
  • 10
  • 9
  • 7
  • 5
  • 5
  • 5
  • 5
  • 5
  • 4
  • 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.
31

The nitrogen compounds of Colorado shale oil

Stauffer, John Cassius, January 1926 (has links)
Thesis (Ph. D.)--Columbia University, 1926. / Vita. "Insecticidal properties of the nitrogen bases of shale oil": p. 42-61. Bibliography: [2] p. at end.
32

The refining of the lower fractions of shale oil by liquid sulfer dioxide ...

Woldman, Norman Emme, January 1927 (has links)
Thesis (Ph. D.)--Columbia University, 1927. / Vita. Bibliography: p. [66-67].
33

Chemical and thermal effects on wellbore stability of shale formations

Yu, Mengjiao. January 2002 (has links) (PDF)
Thesis (Ph. D.)--University of Texas at Austin, 2002. / Vita. Includes bibliographical references. Available also from UMI Company.
34

The Pliensbachian-Toarcian (Lower Jurassic) extinction event

Little, Crispin T. S. January 1995 (has links)
No description available.
35

Paleoenvironmental Implications of the Indidura Formation (Cenomanian/Turonian), Northeastern Mexico: a High Resolution Stratigraphic Study

Duque-Botero, Fabian 02 June 2006 (has links)
High-resolution lithostratigraphic data from rock sequences known as the Indidura Formation near Parras de La Fuente, Coahuila, NE Mexico, led to achieve a significant improvement of our knowledge of that Formation. The results of this study indicate for the first time that the sequence at Parras de La Fuente developed from the deposition of calcareous cyanobacterial microspheroids that accumulated under perennial blooms during the Late Cenomanian through the Middle Turonian. Multi-proxy analyses included sedimentological, petrographical, scanning electron microscopy, stable isotope, trace element geochemistry, and paleontological data. The combined results allowed the correlation of δ13C and anomalies in Mo, V, and Cr with the abundance and predominance of calcareous cyanobacterial microspheroids, which were the main suppliers of the carbonate components and the organic matter throughout deposition of the Indidura Formation in the Parras de la Fuente area, under dysoxic/anoxic conditions. Conspicuous interbeds of dark and light-gray laminated marly calcilutites, and dark-gray marlstones that characterize the stratigraphic sequence formed in response to external forcing climatic factors of millennial-scale Milankovitch cycles (ca. 20 ka precession). At the microscopic level, the prominent dark and light-gray laminae were formed during cycles similar to the 10 to 15 years solar irradiance maximum, and represent alternating periods of high and low calcareous cyanobacterial microspheroids productivity.
36

Characterization of the engineering behavior of nondurable shales

Masada, Teruhisa January 1986 (has links)
No description available.
37

Sorption of organic compounds on oil shale materials and sorption of selected chemicals on a Western soil

Lu, Yeong-Wei January 1986 (has links)
The sorption capacity of a raw shale (Anvil Points), three spent shales, (Antrim, Oxy 6, and Run 16), and a western soil for three organic compounds (2-Hydroxynaphthalene, 1,2,3,4-Tetrahydroquinoline, and 2,3,5-Trimethylphenol) was evaluated by batch and column sorption studies. In addition, the sorption capacity of the western soil for selected inorganic agents (arsenic, cadmium, calcium, potassium, iron, ammonium, fluoride, and sulfate) was also determined. The results of the study showed that the sorption capacity of oil shales for organic compounds varied with the retorting conditions of spent shales, the characteristics of sorbates, and the number of different sorbates present. The overall sorption capacity of the oil shales and the soil were greatly enhanced in multi-sorbate solutions. On the other hand, mutual inhibition for sorption of individual compounds was evident throughout the study. The western soil, in general, exhibited a better sorption capacity for organic compounds than Anvil, Oxy 6, and Run 16 shale, yet Antrim shale appeared to be the best sorbent. Sorption of inorganic ions by soil was closely related to the pH of the solution, and was greatly affected by the interactions between ion species in multi-sorbate solutions. The soil had good affinity for arsenic, cadmium and iron, but little sorption capacity for ammonium and sulfate. Desorption of calcium and potassium from the soil was evident. / M. Eng.
38

Relations spatiales et génétiques entre uranium, sulfures et matières organiques : application aux shales et schistes noirs / Spatial and genetic relationships between uranium, sulfides and organic matter : application to black shales and black schists

Lecomte, Andreï 30 January 2014 (has links)
Dans de nombreux gisements métalliques, notamment en contexte sédimentaire et en particulier dans le cas des shales noirs, des relations spatiales voire génétiques sont décrites entre la matière organique et les métaux. Une série de shales/schistes noirs affectés par des conditions thermo barométriques croissantes a été sélectionnée afin d'étudier le comportement et le devenir de l'uranium de la sédimentation au métamorphisme. Dans les Alum Shales cambro ordoviciens (Suède) faiblement enfouis, l'uranium reste dispersé et n'apparaît sous aucune forme minéralogique identifiable. Le passage des Alum Shales dans la fenêtre pétrolière et la génération d'hydrocarbures n'a pas provoqué de remobilisation identifiable de la concentration primaire, les hydrocarbures migrés ne transportant pas l'uranium. En revanche, le métamorphisme de faciès schiste vert associé à l'orogénèse calédonienne a entraîné une réexpression de la minéralisation uranifère sous la forme d'uraninite, d'urano titanates et/ou de phospho silicates à U, Ti, Zr, Y. Dans le cas des schistes noirs paléoprotérozoïques de Talvivaara (Finlande), le métamorphisme de faciès amphibolite a provoqué la remobilisation de l'uranium synsédimentaire et la cristallisation synmétamorphique, pendant l'orogénèse svécofennienne à 1880 1870 Ma, de cristaux d'uraninite fréquemment inclus dans des nodules carbonés. Cette étude montre que l'uranium, préconcentré au moment de la sédimentation, reste immobile pendant les premiers stades d'enfouissement mais est remobilisé dans les conditions P T croissantes et cristallise sous forme d'oxydes d'uranium pouvant évoluer vers des (phospho-)silicates d'uranium / In many metallic deposits, especially in sedimentary context and particularly in black shales, spatial or genetic relationships are described between organic matter and metals. Several black shales/schists affected by increasing thermo barometric conditions were selected to study the behavior and fate of uranium from sedimentation to high grade metamorphism. In shallow buried cambro ordovician Alum Shales (Sweden), uranium is dispersed and is not detectable as a particular mineralogical expression. Thermal maturation of the Alum Shales and hydrocarbon generation did not cause any identifiable remobilization of primary concentration, since migrated hydrocarbons did not carry uranium. In contrast, greenschist facies metamorphism associated with the Caledonian orogeny resulted in a re expression of uranium mineralization as uraninite or urano titanate crystals, which may evolve into U Ti Zr Y phospho silicates. In the case of Talvivaara, amphibolite facies metamorphism caused remobilization of synsedimentary uranium and synmetamorphic crystallization, during Svecofennian orogeny at 1880 1870 Ma, of uraninite crystals that are frequently included in carbonaceous nodules. This study shows that uranium, which is preconcentrated during sedimentation, remains immobile in the early stages of burial but is remobilized with increasing PT conditions and crystallizes as uranium oxides and/or uranium (phospho-)silicates
39

Joint non-linear inversion of amplitudes and travel times in a vertical transversely isotropic medium using compressional and converted shear waves

Nadri, Dariush January 2008 (has links)
Massive shales and fractures are the main cause of seismic anisotropy in the upper-most part of the crust, caused either by sedimentary or tectonic processes. Neglecting the effect of seismic anisotropy in seismic processing algorithms may incorrectly image the seismic reflectors. This will also influence the quantitative amplitude analysis such as the acoustic or elastic impedance inversion and amplitude versus offsets analysis. Therefore it is important to obtain anisotropy parameters from seismic data. Conventional layer stripping inversion schemes and reflector based reflectivity inversion methods are solely dependent upon a specific reflector, without considering the effect of the other layers. This, on one hand, does not take the effect of transmission in reflectivity inversion into the account, and on the other hand, ignores the information from the waves travelling toward the lower layers. I provide a framework to integrate the information for each specific layer from all the rays which have travelled across this layer. To estimate anisotropy parameters I have implemented unconstrained minimization algorithms such as nonlinear conjugate gradients and variable metric methods, I also provide a nonlinear least square method, based on the Levenberg-Marquardt algorithm. In a stack of horizontal transversely isotropic layers with vertical axis of symmetry, where the layer properties are laterally invariant, we provide two different inversion schemes; traveltime and waveform inversion. / Both inversion schemes utilize compressional and joint compressional and converted shear waves. A new exact traveltime equation has been formulated for a dipping transversely isotropic system of layers. These traveltimes are also parametrized by the ray parameters for each ray element. I use the Newton method of minimization to estimate the ray parameter using a random prior model from a uniform distribution. Numerical results show that with the assumption of weak anisotropy, Thomsen’s anisotropy parameters can be estimated with a high accuracy. The inversion algorithms have been implemented as a software package in a C++ object oriented environment.
40

The role of bacteria in the deposition and early diagenesis of the Posidonienschiefer, a Jurassic oil shale in southern Germany

Hiebert, Franz Kunkel, January 1988 (has links) (PDF)
Thesis (M.A.)--University of Texas at Austin, 1988. / Vita. Includes bibliographical references (leaves 116-124).

Page generated in 0.2948 seconds