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Full-Text Articles in Engineering

Numerical Studies Of Flow In Porous Media Using An Unstructured Approach, Nathan Matthew Lane Jan 2011

Numerical Studies Of Flow In Porous Media Using An Unstructured Approach, Nathan Matthew Lane

LSU Doctoral Dissertations

Flow and transport in porous media is relevant to many areas of engineering and science including groundwater hydrology and the recovery of oil and gas. Porous materials are characterized by the unique shape and connectivity of the internal void structures which give rise to a large range in macroscopic transport properties. Historically an inability to accurately describe the internal pore-structure has prevented detailed study of the role of pore structure on transport. In recent decades however, the combination of high resolution imaging technologies with computational modeling has seen the development of fundamental pore-scale techniques for studying flow in porous media. …


Photochemical Reaction Products Of Polycyclic Aromatic Hydrocarbons Adsorbed At An Air-Water Interface, Franz Stefan Ehrenhauser Jan 2011

Photochemical Reaction Products Of Polycyclic Aromatic Hydrocarbons Adsorbed At An Air-Water Interface, Franz Stefan Ehrenhauser

LSU Doctoral Dissertations

Polycyclic aromatic hydrocarbons (PAH) are ubiquitous pollutants resulting from incomplete combustion and hence normally unavoidable. The kinetic aspects of the environmental degradation process have received considerable attention; however, not much is known about the degradation products themselves. Aqueous solutions of naphthalene, acenaphthene, 9H-fluorene, phenanthrene and pyrene were subjected to UVB light in a bulk-phase and a thin-film reactor to assess the identity of the formed photodegradation products. To aide in the challenging analysis of these mixtures, a novel analytical technique based on high performance liquid chromatography (HPLC) coupled to UV diode-array detection and dopant-assisted atmospheric pressure photoionization mass …


Catalytic Process For The Conversion Of Synthesis Gas To Ethanol For Use As An Alternative Fuel, Nitin Kumar Jan 2011

Catalytic Process For The Conversion Of Synthesis Gas To Ethanol For Use As An Alternative Fuel, Nitin Kumar

LSU Doctoral Dissertations

Higher alcohols are increasing as a proportion of the transportation fuel market, and can be used as neat fuels, or as blends with conventional fuels. For a number of reasons, these C2+-alcohols will be of interest in the foreseeable future. Large-scale production of higher alcohols will likely be carried out via syngas, which can be produced from a number of feedstocks, including coal, natural gas and biomass. Rhodium-based catalysts have been found to be the most active/selective for higher alcohols. However, the literature shows that the yields of C2+-alcohols that can be achieved with current catalysts, even the most active/selective, …


Surface Functionalization Of Crystalline Silicon Substrates, Sri Sai Vegunta Jan 2011

Surface Functionalization Of Crystalline Silicon Substrates, Sri Sai Vegunta

LSU Doctoral Dissertations

In this work, various chemical and electrochemical methods were demonstrated to attach application-specific organic monolayers to crystalline silicon substrates. In one study, alkyl monolayers were anodically electrografted or thermally grafted onto planar (100) silicon substrates using Grignard precursors. The results show electrografted methyl monolayers provide a stable Si-C termination, resisting oxidation on (100) surfaces for approximately 55 days in air. The alkyl termination could provide a potential alternative to defective native oxides and kinetically unstable hydride surfaces. A mechanism involving two electron transfers per grafting event was established for both the thermal and electrochemical routes. In another study, unsaturated organic …


Analytical Design Method For Cold Production Of Heavy Oil With Bottom Water Using Bilateral Sink Wells, Wenting Qin Jan 2011

Analytical Design Method For Cold Production Of Heavy Oil With Bottom Water Using Bilateral Sink Wells, Wenting Qin

LSU Doctoral Dissertations

Few heavy oil reservoirs with strong bottom water drives have been developed successfully because of severe water coning. Water coning tends to cause low ultimate recovery, low well productivity, and high water production. Although thermal and gravity-assisted methods might improve recovery in oil reservoirs, such methods are widely perceived as either economically unfavorable or technologically infeasible. This study proposes a new, cold production technique, called Bilateral Water Sink (BWS), to meet those challenges. The BWS method suppresses water cresting by producing oil and water simultaneously from separate, horizontal wells completed in the oil and water zones; the oil and water …


Silicon Nanowire Anode For Lithium-Ion Batteries: Fabrication, Characterization And Solid Electrolyte Interphase, Wanli Xu Jan 2011

Silicon Nanowire Anode For Lithium-Ion Batteries: Fabrication, Characterization And Solid Electrolyte Interphase, Wanli Xu

LSU Doctoral Dissertations

Depletion of fossil fuels and concerns over CO2 emission have driven the development of electric vehicles (EVs) with high-energy efficiencies and low emissions. Lithium-ion rechargeable batteries, compared to lead acid, nickel cadmium, nickel metal hydroxide, and other popular rechargeable batteries, are considered as the most promising candidates for EVs for their high operating voltage and high energy density. Silicon nanowires are considered as lithium-ion battery anodes for their ultra high capacity at 4200 mAh·g-1 (10× higher than conventional graphite anode), as well as stress accommodation for reversible lithiation and delithiation. Silicon nanowires were fabricated via metal assisted electroless etching, and …


Catalytic Hydrogenation Of Co To Higher Alcohols, Nachal Devi Subramanian Jan 2011

Catalytic Hydrogenation Of Co To Higher Alcohols, Nachal Devi Subramanian

LSU Doctoral Dissertations

The interest in converting synthesis gas to alcohols and oxygenated fuel additives via CO hydrogenation is growing rapidly due to the increasing rise in oil prices. Among the potential end products, ethanol is desirable since it serves as a clean alternative fuel, a gasoline blend, and a hydrogen carrier to supply fuel cells. The high cost and limited availability of the most active/selective Rh-based catalysts has led to the development of base metal catalysts such as modified Cu-based catalysts. Literature suggests that a combination of Co (or Mn) with Cu can facilitate higher alcohol formation by a non-dissociative adsorption of …


Characterization Of Foam Flow In Pipes Using Two Flow Regime Concept, Rahul Narayanrao Gajbhiye Jan 2011

Characterization Of Foam Flow In Pipes Using Two Flow Regime Concept, Rahul Narayanrao Gajbhiye

LSU Doctoral Dissertations

The objective of this study is to investigate the characteristics of foam flow behavior in pipes in a wide range of experimental conditions, including two pipe materials (stainless steel and nylon pipes with about 0.36 - 0.38 inch in inner diameter and 12 ft in length), three surfactant formulations (Cedepal FA-406, Stepanform-1050, and Aquet-944), and three surfactant concentrations (0.1, 0.5, and 5 wt%). The concept of “two foam-flow regimes”, consisting of high-quality regime and low-quality regime, is at the heart of interpreting the experimental data. The experimental results in horizontal pipes showed the presence of two distinct high-quality and low-quality …