Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 438 for “"Calcite"”.
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Color centers in calcite
Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Physics, 1961.
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A theoretical investigation of deformation mechanisms in calcite
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Geology and Geophysics, 1964.
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Modelling calcite dissolution in a rotating disc reaction vessel
… in many natural and industrial processes. For calcite dissolution, the kinetics and mass transport of the dissolved species reflect both the chemistry of the bulk, and the conditions at the dissolving interface. We formulate the dissolution problem as a set of coupled convection- …
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Antibacterial calcite created with a multilayer polyelectrolyte coating method
… to be used for water treatment purposes. Calcite is a naturally occurring mineral in natural aqueous environments which mitigates the negative environmental impact of these materials versus previously used silver nanoparticles. Polycationic natural and synthetic polymers have been shown to …
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Biochemical approaches to investigate biomineralization of magnesium calcite and aragonite
… as three anhydrous polymorphs, namely, the calcite, aragonite and vaterite. Of these, marine organisms generally employ either calcite (usually with small amounts of magnesium ions replacing Ca2+ ions in the lattice) or aragonite form of the mineral. This thesis is focused on understanding …
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Nanoscale insight into tribomechanical and hydrothermal process at calcite surface
… Among the minerals that compose the lithosphere, calcite is particularly significant due to its abundance, ductility, and reactivity in aqueous environment. The induced dissolution and precipitation, commonly described as pressure solution and cementation, actively reconstruct calcite surfaces and …
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Transport properties and mechanical behavior of synthetic calcite-quartz aggregates
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 1997.
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High temperature deformation mechanisms and strain heterogeneities in calcite rocks
… a common impurity, on the mechanical behavior of calcite rocks. The results indicate that increasing Mg content increases the strength of calcite rocks during dislocation creep. The anisotropic nature of crystal slip usually entails variations in reorientation of individual grains and …
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Oxygen stable isotopic analysis of calcite by Raman microprobe spectrometry
… <1‱). Five natural and two synthetic ¹⁸O doped calcites were analyzed using the laser Raman microprobe (LRM) to determine whether the intensity ratio of the C¹⁸O¹⁶O₂²⁻ and C¹⁶O₃²⁻ symmetric stretching bands can be directly related to isotopic compositions measured by ratio mass spectrometry …
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Effect of ionic strength on heterogeneous nucleation of calcite during biomineralization
… are inert. In this study, we investigate calcite nucleation onto two model organic matrix polysaccharides, chitosan and alginate, in a series of ionic strength solutions (65 – 600 mM NaCl). Chitosan is near-neutral (at pH 8.5) and analogous to the structural polysaccharide chitin. In …
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Calcite cements in carbonates of the Sverdrup Basin, Canadian Arctic Archipelago.
Calcite cements from the Upper Paleozoic sequences 2, 3 and 4 of the Sverdrup Basin (Canadian Arctic Archipelago) are the subject of this study. On a micro-scale, petrography with light microscopy, cathodoluminescence (CL), scanning electron microscopy (SEM) and staining helped to identify two main …
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Water Column Productivity, Calcite Precipitation, and Phosphorus Dynamics in Freshwater Marshes
… carbonate minerals. During the precipitation of calcite (CaCO3) other chemical species such as phosphorus (P) can sorb onto the newly forming crystals and thus be removed from thewater column. While calcite precipitation and subsequent P removal have been studied extensively in lakes, rivers, and …
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Calcite Cementation of Sixty-Five-Year-Old Aragonite Sand Dredge Pile
… grains completely cemented with 4 micron calcite spar. Beneath this crust, micritized aragonite grains are cemented by sparry calcite cements with meniscus and isopachous textures. The amount of cement ranges from 7–16%. Cement volume decreases with depth; the deepest samples contain …
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Boron in Foraminiferal Calcite as an Indicator of Seawater Carbonate Chemistry
… The ratio of boron to calcium (B/Ca) in the calcite tests of planktic foraminifers has previously been suggested as a proxy for past seawater carbonate chemistry, but controls on B incorporation are not yet clear. The theoretical basis for this proxy is rooted in the pH-dependent …
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Diffraction and Spectroscopy of Marine Calcite Biominerals: Insights into Structure and Geochemistry
… are based on chemical information stored in the calcite biominerals produced by marine organisms. Organisms such as foraminifera and coccolithophores provide an unparalleled 'proxy’ archive of past marine conditions. The way in which these organisms record these proxy archives is largely unknown, …
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Experimental studies of pressure solution and crack healing in halite and calcite
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 1989.
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Water on Calcite (10.4) and K-Feldspar (001) - Adsorption Structure and Desorption Kinetics -
… two particularly interesting mineral surfaces, calcite (10.4) and K-feldspar (001), are investigated. Calcite is the most abundant carbonate mineral in the Earth’s crust. Despite its abundance, a central surface property, the presence of a surface reconstruction, remained elusive so far. Only …
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