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.
Results
Showing 1 to 20 of 22 for “"Carbonate formation"”.
-
Geomechanical Stability Analysis for Co2 Sequestration in Carbonate Formation
… of CO2. Large scale CO2 sequestration in deep carbonate formation is a complicated geological process, which will non-reversibly transform the presumed equivalent and stable status of a sedimentary basin that formed over millions of years: chemically, hydraulically, geothermally, and …
-
Calcium Carbonate Formation in Water Distribution Systems and Autogenous Repair of Leaks by Inert Particle Clogging
The formation of calcium carbonate (CaCO3) (i.e. scale) in potable water systems has long been a concern in water treatment and distribution. A literature review reveals that CaCO3 scaling issues are re-emerging due to climate change, temperature increases in hot water systems and lower use of …
-
Biomolecular Controls on Calcium Carbonate Formation by Amorphous and Classical Pathways: Insights from Measurements of Nucleation Rates and Isotope Tracers
… of organic matrices to actively guide the formation of crystal structures. The timing and placement of the subsequent minerals that form are most easily controlled during nucleation; however, a physical and chemical picture of how organic functional group chemistry influences the initial …
-
Microfluidic H2/O2 fuel cells for contaminant and electrode analysis
… inexpensive non-noble metal catalysts. However, carbonate formation from carbon dioxide in air has long been considered a significant hurdle for liquid electrolyte-based AFC technologies. Carbonate formation consumes hydroxyl anions, which leads to (i) reduced electrode performance if formed …
-
The origin and behaviour of carbonate minerals in diverse environments: from subduction zones to asteroids
Carbonate minerals are some of the most important carbon storage materials in both terrestrial and asteroidal settings. Understanding the origin and behaviour of carbonates as a function of pressure, temperature, and composition of coexisting phases is therefore crucial for modelling carbon fluxes. …
-
Calcium isotope insight into the global carbon cycle
… the sedimentary sink for carbon. The formation of authigenic carbonate in marine sediments is caused by the microbial degradation of organic matter. I used pore fluid measurements and a numerical model to identify zones of authigenic carbonate precipitation. This knowledge was then …
-
Interpretation and Fracture Characterization of Early-Cretaceous Buda Limestone Formation Using Post-Stack 3D Seismic Data in Zavala County, Texas
… is a naturally fractured Early Cretaceous carbonate formation in south Texas which unconformably underlies the Eagle Ford Shale. Matrix porosity of the Buda is less than 6%, therefore natural fractures improve the potential for commercial hydrocarbon production from this tight limestone …
-
Developing durable electrodes for selective electroreduction of CO2 to value-added intermediates
… modes include catalyst agglomeration, carbonate formation, and binder dissolution. This chapter concludes by proposing a standard durability testing protocol applicable to all ECO2RR setups and providing data for a 50 h durability study in a membrane electrode assembly-based …
-
Carbon and mineral transformations in seafloor serpentinization systems
… examines abiotic processes controlling the transformation and distribution of carbon compounds in seafloor hydrothermal systems hosted in ultramafic rock. These processes have a direct impact on carbon budgets in the oceanic lithosphere and on the sustenance of microorganisms inhabiting …
-
Carbon and mineral transformations in seafloor serpentinization systems
… examines abiotic processes controlling the transformation and distribution of carbon compounds in seafloor hydrothermal systems hosted in ultramafic rock. These processes have a direct impact on carbon budgets in the oceanic lithosphere and on the sustenance of microorganisms inhabiting …
-
Pedogenic carbonates in loess formation rates, formation conditions and source apportionment assessed by isotopes and molecular proxies
Interest in secondary (pedogenic) carbonates as an archive for paleoclimatic reconstructions in arid and semiarid regions has increased during recent decades. Their carbon (C) isotope composition represents the conditions prevailing during their formation because they are formed by precipitation of …
-
CO2 Separation Using Regenerable Magnesium Solutions Dissolution, Kinectics and VLSE Studies
… of Mg(OH)2 for continuous CO2 absorption, formation of an unwanted by-product magnesium carbonate (MgCO3), and vapor-liquid-solid equilibrium (VLSE) of the system were studied. The dissolution of Mg(OH)2 and the release of magnesium ions into the solution to maintain a level of alkalinity …
-
Oil Potential of Middle Cretaceous Tight Carbonate in Mexico
… investigates a tight overpressured Cretaceous carbonate formation in Field A of Mexico. The Cretaceous carbonate was penetrated by well A1 and tested oil successfully during an open-hole test covering interval 5356 to 5515 m (MD) that produced oil of 33 degrees API. Initial pressure was 1050 …
-
The geochemistry of fossil termite nests in Calitzdorp, Western Cape, South Africa
… movement frequently leads to post-construction carbonate precipitation within termitaria. Fossil termitaria near Calitzdorp, Western Cape, South Africa, were described nearly two decades ago, but no detailed work has been performed on them until now. Here, these calcretised Quaternary features, …
-
The Influence of dust deposition, carbonates and erosion on the formation of Clanwilliam heuweltjies
… an equally likely explanation for heuweltjie formation. The aim of this investigation was firstly to determine the influence of dust deposition and carbonates on heuweltjie formation in order to gain insight into the formative process of heuweltjies. The second part of this investigation …
-
Evaluation of Cathode Materials for Low Temperature (500-700C) Solid Oxide Fuel Cells
… This phase was attributed to surface A-site carbonate formation due to exposure to atmospheric CO<sub>2</sub>.</p> <p>Symmetric cells were prepared and electrochemically characterized using AC impedance spectroscopy in a range of 500-700°C, and a PO<sub>2</sub> of 1.0-0.01 atm. The BSCF was …
-
Investigation of contaminant effects and cathode catalysts in microfluidic fuel cells
… are largely limited to whole cell analytical information (e.g. polarization and power density curves). We have previously used a microfluidic H2/O2 fuel cell as an analytical platform to determine the effects of carbonate formation in alkaline fuel cells. The microfluidic fuel cell has modular …
-
Study of reactive flow, ground deformation and real-time tomography with applications on CO₂ sequestration
… uplift owing to sequestration of CO₂ in a carbonate saline aquifer, and a validation of a new, real-time, tomography method that monitors the velocity change resulting from hydraulic fracturing. In Chapter 2, a network approach that models the formation of wormholes from reactive flow of …
-
Oxygen Transport Membrane Reactors for Oxy-Fuel Combustion and Carbon Capture Purposes
… mechanical and chemical instabilities due to the carbonate formation on the perovskite structure. The addition of SDC in the membrane composition produces a dual-phase OTM which is observed to improve the oxygen permeation flux when subjected to pure CO2 sweeping gases. When subjected to pure …
-
Linking the kinetics of formation and growth to the mechanical properties of calcium carbonate composites
Calcium carbonate, the most common among other biogenic minerals, is widely used in skeletal components in marine organisms. These organisms exploit varied physical and chemical interactions between calcium carbonate and organic additives to direct the precipitation process through thermodynamic …
Page 1 of 2