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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.
41

Eo-Variscan Orogenesis in the Guilleries Massif, Catalan Coastal Ranges, Northeastern Spain Recorded by U-Th-Pb ages of Monazite Inclusions in Metamorphic Garnet

Wise, Julia L. January 2012 (has links)
No description available.
42

Analysis of the Gouldsboro Pluton and the Fehr Granite: Understanding the Scales of Magmatic Processes and Partial Melt Generation from the Deep to Shallow Crust

Koteas, George Christopher 01 September 2010 (has links)
The heterogeneity of the continental crust has a first order control on the dynamics of plate tectonic processes and the compositions of the Earth in both time and space. Heterogeneity can be characterized at a variety of scales and in a multitude of tectonic environments, but it is the links between seemingly disparate tectonic settings and crustal levels that are critical in understanding construction of the continents. The focus of this dissertation work is to apply microtextural, microgeochemical, whole rock geochemical and traditional petrographic techniques to study features in both deep and shallow crustal igneous rocks. The goal of these efforts is to better understand the roles that magmatic processes, mafic-felsic magma interaction, and partial melting have on the evolution of continental crust. Two principal field areas were selected, the Gouldsboro pluton in coastal Maine and the Fehr granite in northern Saskatchewan, Canada, because they each represent end-members of the processes involved with the generation, modification, transport, and emplacement of magmas that build continental crust. Evidence for bimodal magmatism preserved in the Silurian age Gouldsboro pluton has led to a refined model for the construction of shallow crustal magma chambers. Research efforts focused on the Neoarchean Fehr granite and Paleoproterozoic Chipman dike swarm have contributed to the current understanding of the links between high temperature metamorphism (migmitization) and the production of new felsic magmas as well as the rheological and chemical influences of mafic-felsic magma interaction in the deep crust. The results of these combined field and laboratory efforts have demonstrated the important role of mafic-felsic magma interaction on the strength and composition of both deep and shallow continental crust and have contributed to the current understanding of the complex links between deep crustal heterogeneity and bimodal magmatism at shallow crustal levels.
43

Zircon, monazite, and xenotime as provenance indicators in selected Precambrian crystalline rocks, Black Hills uplift, South Dakota

Hark, Jessica Sandra 15 July 2009 (has links)
No description available.
44

The design, implementation and applications of a beam rocking system for a nuclear microprobe

Kerckhove, Diane G. de January 1999 (has links)
No description available.
45

Arsenic Distribution and Speciation in Antigorite-Rich Rocks from Vermont, USA

Niu, Lijie 07 September 2011 (has links)
Summary Serpentinites from the northern Vermont were examined for the distribution and abundance of As. XRD and electron microprobe showed the samples are composed of antigorite, chromite, magnetite, and carbonate minerals (magnesite, dolomite, calcite). The concentration in As when the samples were dissolved in H3PO4 was 10% of the concentration in As when the samples were dissolved in concentrated HF/HNO3, suggesting that As is mainly incorporated in the structure of antigorite. X-ray absorption near-edge structure spectra showed that the As is As(III) in the samples. Extended X-ray absorption fine structure spectra suggested that the As has a tetrahedral coordination and is located in the Si-site in serpentine.
46

Arsenic Distribution and Speciation in Antigorite-Rich Rocks from Vermont, USA

Niu, Lijie 07 September 2011 (has links)
Summary Serpentinites from the northern Vermont were examined for the distribution and abundance of As. XRD and electron microprobe showed the samples are composed of antigorite, chromite, magnetite, and carbonate minerals (magnesite, dolomite, calcite). The concentration in As when the samples were dissolved in H3PO4 was 10% of the concentration in As when the samples were dissolved in concentrated HF/HNO3, suggesting that As is mainly incorporated in the structure of antigorite. X-ray absorption near-edge structure spectra showed that the As is As(III) in the samples. Extended X-ray absorption fine structure spectra suggested that the As has a tetrahedral coordination and is located in the Si-site in serpentine.
47

Study of Chip-Level EMI Based on Near-Field Measurement Techniques

Hsieh, Hsin-Feng 08 August 2012 (has links)
This thesis proposed a near-field electromagnetic interference measurement framework to obtain sensitivity and spatial resolution of the characteristic parameters of magnetic probe based on International Electrotechnical Commission proposed for integrated circuits electromagnetic radiation measurement standards IEC 61967-6 : magnetic probe method. Using cross-coupled planar microwave bandpass filter which is realized by glass fiber board (FR4) for near-field measurement and electromagnetic simulation in comparsion. Nowadays, integrated circuits has become an important source of energy of overall electromagnetic interference in electronic systems. Finally, do near-field scanning measurement for a 64-pin wire-bond quad flat nonlead (WB-QFN) package and the voltage-controlled oscillator chip in 0.18 £gm CMOS technology by using high scanning resolution of microprobe. Then observes the chip-level and package-level electromagnetic interference, and achieve chip-level of near-field electromagnetic interference measurement techniques.
48

Natural fracture cementation in the Marcellus Formation

Pommer, Laura Elizabeth 03 February 2014 (has links)
In order to test the hypothesis that fractures in outcrops are equivalent to subsurface fracture systems I compare fracture cement morphology, texture, mineralogy and geochemistry from a suite of outcrop samples from Union Springs, NY, with fractures in four cores from a currently producing reservoir in southwest Pennsylvania. Transmitted light-microscope petrography and cold cathodoluminescence of calcite of outcrop and core samples reveals a variety of cement morphologies including crack-seal and blocky fracture cement textures that are interpreted as a record multiple repeated stages of fracture opening and sealing, as well as fibrous calcite fill and other mineral phases. The stable isotopic composition of calcite fracture cements from different fracture types in cores and outcrop range from -21.5 to +4.4‰ δ13C PDB and -8.0 to -12.0 ‰ δ18O PDB and indicate calcite precipitation temperatures between 46 and 89°C. Fluid inclusion microthermometry from secondary fluid inclusions indicates trapping temperatures between 110 and 120°C. Microprobe analysis of fracture calcite cement indicates a range in Fe, Mn, and Mg composition, with subsurface and outcrop cement of similar composition. Assuming burial history predicts thermal history, isotopic compositions together with fluid inclusions suggest calcite precipitated in vertical fractures during prograde burial, during the Acadian to early Alleghanian orogenies. These findings indicate that fractures in outcrops of the Marcellus Formation can be used as a proxy for those in the subsurface. / text
49

A study of the effects of oxygen environment on the stoichiometry, phase assemblage and stability of BiSCCO 2212 and 2201 using EPMA

Rowan, Fraser S. January 2001 (has links)
A method of performing accurate oxygen analysis on cuprate based superconducting materials was established using electron probe micro analysis (EPMA). A range of YBa<sub>2</sub>Cu<sub>3</sub>O<sub>δ</sub> ceramics with varying oxygen concentration were used to test the method. Using YBCO as a reference material, a suitable standard for oxygen analysis of Bi<sub>2</sub>Sr<sub>2</sub>CaCu<sub>2</sub>O<sub>δ</sub> (BiSCCO-2212) materials was obtained. This standard was used to perform full elemental analysis of a range of BiSCCO-2212 crystals, post annealed in pO<sub>2</sub>'s between 10<sup>-5</sup>-2atm. When the average Cu valence of each crystal was calculated and plotted as a function of the critical temperature (T<sub>c</sub>) for each crystal, it was shown that BiSCCO-2212 materials conformed to the 'universal' trend illustrated by most other HTS and did not exhibit anomalous behaviour as had been previously believed. The phase assemblage and superconducting properties of BiSCCO-2212 Ag-clad multifilamental wires, prepared using the powder-in-tube (PIT) method by BICC, were studied as a function of a time/temperature profile. pO<sub>2</sub> of the processing atmosphere was found to be the predominant factor in determining the stoichiometry of the 2212 phase within wires. The phase assemblage is not simply a function of pO<sub>2</sub> as previously believed and can be controlled, in part, by the post annealing temperature. Homogenisation of the phase assemblage in BiSCCO-2212 Ag-clad wires can be achieved by prolonged heating (96hrs) at an appropriate temperature. An investigation into the 10K superconducting BiSCCO phase has shown the Sr-rich solid solution to extend towards the ideal stoichiometry of 2:2:1 (Bi:Sr:Cu) with increasing pO<sub>2</sub>. Using a combination of high pO<sub>2</sub> (60atm) to achieve the appropriate Bi:Sr stoichiometry followed by post annealing in N<sub>2</sub> to adjust the oxygen content, it was possible to prepare single-phase ceramics of stoichiometry Bi<sub>2.11(2)</sub>Sr<sub>1.90(2)</sub>Cu<sub>0.99(2)</sub>O<sub>δ</sub> with a T<sub>c</sub>=10.5K(5).
50

Arsenic Distribution and Speciation in Antigorite-Rich Rocks from Vermont, USA

Niu, Lijie 07 September 2011 (has links)
Summary Serpentinites from the northern Vermont were examined for the distribution and abundance of As. XRD and electron microprobe showed the samples are composed of antigorite, chromite, magnetite, and carbonate minerals (magnesite, dolomite, calcite). The concentration in As when the samples were dissolved in H3PO4 was 10% of the concentration in As when the samples were dissolved in concentrated HF/HNO3, suggesting that As is mainly incorporated in the structure of antigorite. X-ray absorption near-edge structure spectra showed that the As is As(III) in the samples. Extended X-ray absorption fine structure spectra suggested that the As has a tetrahedral coordination and is located in the Si-site in serpentine.

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