Engineering Commons^™

Fabrication And Modification Of Titania Nanotube Arrays For Harvesting Solar Energy And Drug Delivery Applications, Ahmed El Ruby Abdel Rahman Mohamed

Electronic Thesis and Dissertation Repository

The fast diminishing of fossil fuels in the near future, as well as the global warming caused by increasing greenhouse gases have motivated the urgent quest to develop advanced materials as cost-effective photoanodes for solar light harvesting and many other photocatalytic applications. Recently, titania nanotube arrays (TNTAs) fabricated by anodization process has attracted great interest due to their excellent properties such as: high surface area, vertically oriented, highly organized, one-dimensional, nanotubular structure, photoactivity, chemical stability and biocompatibility. This unique combination of excellent properties makes TNTAs an excellent photoanode for solar light harvesting. However, the relatively wide band gap energy of …

Hydrodeoxygenation Of Anisole In A Novel Externally Agitated Reactor, Brett Pomeroy

Electronic Thesis and Dissertation Repository

Bio-oil upgrading via hydrodeoxygenation (HDO) was investigated using anisole, a model compound, in a novel Externally Agitated (EA) reactor which is expected to enhance gas-liquid-solid mixing. Operating conditions were established based on anisole HDO with 10 wt.% Ni on silica, γ-alumina, and δ-alumina while varying temperatures between 160 to 280^oC, and reaction times between 30 – 90 minutes. Mild temperatures of 220^oC and 45 minutes for reaction time with γ-alumina were selected for subsequent work since γ-alumina demonstrated the highest HDO activity. HDO was then investigated with varying Ni-Cu and Ni loadings. Despite the improved reducibility …

Hydrothermal Decarboxylation Of Fatty Acids And Their Derivatives For Liquid Transportation Fuels, Md Zakir Hossain

Electronic Thesis and Dissertation Repository

Due to the depletion of fossil fuel reserves, renewable resources are required to produce tomorrow’s fuel range hydrocarbons. This thesis focuses on the hydrothermal decarboxylation of fatty acids and their derivatives derived from renewable sources. These are required for liquid transportation fuels which have similar properties to conventional fuels. Detailed catalytic studies were performed for the decarboxylation of oleic acid as a model compound and corn distiller’s oil (CDO) as a real feedstock. Commercial activated carbon and laboratory prepared Ni-Al₂O₃, MgO-Al₂O₃, Mo-Al₂O₃ catalysts were also examined as catalysts. Fatty …

Hydrodynamics In The Gas-Driven Inverse Liquid-Solid Fluidized Bed, Jiaqi Huang

Electronic Thesis and Dissertation Repository

A novel reactor named Gas-Driven Inverse Liquid-Solid Fluidized Bed (GDFB for short) was developed in this research. A vertical baffle divides the column into a riser and a downer. Inverse fluidization is driven by the gas and occurs in the downer, where hydrodynamics and their influencing factors were studied. In the solid-baffle system, four fluidization regimes were observed, including the packed bed, semi-fluidized bed, fully-fluidized bed, and circulating bed. Bed expansion ratio was higher for particles with a higher density and a smaller solids loading. Moreover, the average particle velocity was proportional to superficial gas velocity and higher for denser …

Photoactive Properties Of Nanostructured Titania Modified Polyurethanes, Chao Chen

Electronic Thesis and Dissertation Repository

In order to enhance both the photoactivity and physical/mechanical properties of titania/polyurethane (PU) nanocomposites, in-situ polymerization and film casting were investigated. Both self-degrading PU foams and self-cleaning PU coatings were prepared. Functional monomers were prepared usingDMPA (2,2-dimethylolpropionic acid) functionalized anatse TiO₂ and P25 for integration into polyurethane foam with a "grafting-from" synthetic method. This technique was found to successfully reduce the agglomeration effect of titania nanoparticles inside the foams. In addition, the photodegradation rate was enhanced by > 120% over unmodified foam at an optimized loading of 3wt% DMPA functionalized anatase TiO₂. The presence of DMPA functionalized P25 …

Multi-Objective Optimization Of Industrial Ammonia Synthesis, Stanislav Ivanov

Electronic Thesis and Dissertation Repository

The thesis describes modelling and optimization work of an industrial ammonia synthesis. Author developed first-principle mathematical model of the commercial converter based on gas-solid reaction and heat transfer within the system. The model is validated with industrial data and showed satisfactory accuracy. Further, optimization study is performed in multi-objective manner to intensify ammonia production and decrease heat duty of the process. Result have revealed a potential to improve current operating condition int terms of both objectives.

Supercritical Fluid Extraction Of Valuable Chemicals: Application Of Microalgae And Pyrolysis Oil As Feedstocks, Osariemen Ogbeide

Electronic Thesis and Dissertation Repository

In this dissertation, pure and modified carbon dioxide were used as non-conventional solvents for the investigation of lutein, chlorophyll a, chlorophyll b extraction from microalgae and for caffeine extraction from the pyrolysis oil of spent coffee grounds. The use of toxic organic solvents in supercritical fluid extraction has propelled research efforts to develop new solvents that are environmentally friendly and provide faster extraction compared to conventional extraction processes. For this reason, phosphatidylethanolamine (PE), a major phospholipid consisting of 14% of the entire soybean lecithin was acetylated with acetic anhydride, providing a surfactant (N-A-PE).

Then, the synthesized N-A-PE was employed as …