Mechanics of Materials Commons^™

Synthesis And Characterization Of A Novel Polyacetal & Design And Preparation Of Superhydrophobic Photocatalytic Surfaces, Yuanyuan Zhao

Dissertations, Theses, and Capstone Projects

Polyacetal polymers are thermoplastic resins that play an important role in industry because of numerous industrial applications including automobile; household appliance; etc. The first part of this thesis (Chapter 2) is about the synthesis of a new acetal copolymer that exhibits superior thermal stability. The second part of this thesis (Chapter 3) is about the preparation and applications of TiO₂-based polymer nanocomposite films, where the reactive oxygen species (ROS) are generated on the solid surface. Catalytic nanocomposite films are an active area of research because of their potential uses for environmental remediation and chemical synthesis. Furthermore, to …

Transition States And Modeling For Co9s8/Mos2 Catalysis, Gabriel Angel Gonzalez

Open Access Theses & Dissertations

Transition state computational studies of the sulfur removal from dibenzothiophene (DBT) molecule have herein been performed considering the Co9S8/MoS2 interface existing on unsupported Co/MoS2 catalysts. The linear synchronous transit (LST) and quadratic synchronous transit (QST) methods integrated in a density functional theory (DFT) program such as Dmol3 were used for the calculations of energy barriers of the transition states. Three different configurations present on the Co9S8/MoS2 interface have been envisaged as possible catalytic sites: sulfur-sulfur (S, S) sites, and molybdenum-sulfur (Mo, S) and molybdenum-molybdenum (Mo, Mo) edge sites. This study revealed that the (Mo, Mo) edge site is the most …

Transition Metal Carbide (Tmc) Novel Materials For Novel Catalytic Applications, Svetlana Lagoykina

Open Access Theses & Dissertations

Transition metal carbides (TMC) constitute a diverse class of materials and traditionally have many technological applications. TMC became a subject of extensive research since 1973, when their platinum -like properties were discovered. They demonstrated high catalytical activity and selectivity in a variety of chemical reaction and have potential for some novel catalytic application.

This research is an effort to design new high effective, selective and stable bimetal or alkali promoted TMC catalyst. After extensive theoretical research a wide range of TMC, including bimetal and alkali promoted carbides, were synthesized by different methods. All solids were characterized by XRD and microscopy. …

Synthesis And Evaluation Of Sensitizer Drug Photorelease Chemistry: Micro-Optic Method Applied To Singlet Oxygen Generation And Drug Delivery, Goutam Ghosh

Dissertations, Theses, and Capstone Projects

This thesis summarizes a new micro-optic method for singlet oxygen generation and sensitizer drug delivery, which include i) synthesis and evaluation of a first generation device for drug delivery from native and fluorinated silica probe tips, ii) synthesis of PEG conjugated sensitizers to study phototoxicity in ovarian cancer cells, and iii) synthesis and evaluation of tris-PEGylated chlorin conjugated fluorinated silica for its future integration into the device to use as a 2nd generation device. A first generation micro-optic device was developed that works by sparging O2 gas and light generating cytotoxic singlet oxygen that cleaves the covalently attached drug (sensitizer) …

Synthesis, Fabrication And Characterization Of Magnetic And Dielectric Nanoparticles And Nanocomposite Films, Xiaohua Liu

Dissertations, Theses, and Capstone Projects

Materials science is an interdisciplinary field investigating the structure-property relationship in solid-state materials scientifically and technologically. Nanoscience is concerned with the distinctive properties that matter exhibits when confined to physical dimensions on the order of 10^-9 meters. At these length scales, behaviors of particles or elaborate structures are often governed by the rules of quantum mechanics in addition to the physical properties associated with the bulk material.

The work reported here seeks to employ nanocystals, binary nanocomposites and thin films of materials, to build versatile, functional systems and devices. With a focus on dielectric, ferroelectric, and magnetoelectric performance, a …

Metal Nanoparticles Immobilized On Basic Supports As Catalysts For Hydrogenation And Dehydrogenation Reactions Of Relevance To Cleaner Fossil Fuels And Alternative Sources Of Energy, Reena Rahi

Dissertations, Theses, and Capstone Projects

We developed a series of catalysts, composed of metal nanoparticles immobilized on basic supports for the hydrogenation of heteroaromatics of relevance to cleaner fossil fuels and biodiesel, and for the dehydrogenation of heteroaromatics of relevance to hydrogen storage in organic liquids. Our catalyst design involves nanostructured catalysts composed of metal particles immobilized on basic supports capable of ionic mechanism that may avoid catalyst poisoning and enhance catalytic activity.

We prepared a new catalyst composed of Pd nanoparticles immobilized on MgO by NaBH4 reduction of Na2PdCl4 in methanol in the presence of the support. TEM measurements revealed well-dispersed 1.7 nm Pd …

Organic Pi-Stacking Semiconducting Material: Design, Synthesis And The Analysis Of Structure And Properties, Bin Wang

Dissertations, Theses, and Capstone Projects

Organic semiconducting materials have been under intensive investigation in the recent decades for potential applications in various electronic or optoelectronic devices such as light emitting diodes, photovoltaic cells and field effect transistors. Compared to inorganic counterparts, organic charge transport materials are attractive for their abilities of forming thin-films, large area manufacturing, compatibility with flexible substrate, light weight and potential low fabrication cost. The charge transport property of the organic active layer is one of the key factors to the electronic or optoelectronic performance of devices. Research projects presented in this thesis focused on improving charge carrier mobility of organic charge …

Alkali Promoted Molybdenum (Iv) Sulfide Based Catalysts, Development And Characterization For Alcohol Synthesis From Carbon Monoxide And Hydrogen, Belinda Delilah Molina

Open Access Theses & Dissertations

For more than a century transition metal sulfides (TMS) have been the anchor of hydro-processing fuels and upgrading bitumen and coal in refineries worldwide. As oil supplies dwindle and environmental laws become more stringent, there is a greater need for cleaner alternative fuels and/or synthetic fuels. The depletion of oil reserves and a rapidly increasing energy demand worldwide, together with the interest to reduce dependence on foreign oil makes alcohol production for fuels and chemicals via the Fischer Tropsch synthesis (FTS) very attractive. The original Fischer-Tropsch (FT) reaction is the heart of all gas-to-liquid technologies; it creates higher alcohols and …

Preparation Of Mesoporous Silica Supported Ruthenium Oxides And The Application And Kinetic Study In The Catalysis Of Water Oxidation, Yang Zhang

Open Access Dissertations

Photo-induced water splitting of water into H2 and O2 has been a major focus in the development of clean and renewable energy. The development of viable and efficient catalysts that facilitates O2 production remains the major challenge in the study of the corresponding half-reaction of water oxidation. There are plenty of metal oxides reported active in the catalysis of water oxidation. However, several important performance bench marks of those materials, such as the non-stoichiometric production of O2, slow reaction rate and/or low quantum efficiency, remain to be improved.

Ruthenium oxide (RuO2) has long been known as one of the most …

Applications Of Density Functional Theory In Materials Science And Engineering, Manuel Alvarado

Open Access Theses & Dissertations

Density Functional Theory (DFT) is a powerful tool that can be used to model various systems in materials science. Our research applies DFT to two problems of interest. First, an organic/inorganic complex dye system known as a Mayan pigment is modeled to determine chemical binding sites, verifying each model with physical data such as UV/Vis spectra. Preliminary studies on palygorskite-based mayan pigments (mayacrom blue, mayacrom purple) show excellent agreement with experimental studies when using a dimer dye geometry binding with tetrahedrally-coordinated aluminum impurity sites in palygorksite. This approach is applied to a sepiolite-based organic/inorganic dye system using thioindigo attached to …

Observed Superspin-Glass Behavior In Ni0.5zn0.5fe2o4 Nanoparticles, Antony Adair

Open Access Theses & Dissertations

In this investigation we seek to identify the magnetic behavior of Ni0.5Zn0.5Fe2O4 nanoparticles though AC-susceptibility and DC-magnetization measurements. Powder x-ray diffraction was performed to determine the purity and average diameter ( ~ 9nm) of the particles. Aditionally, structure was confirmed by comparison through the International Centre for Diffraction Data's Powder Diffraction File [52] (PDF # 08-0234).

Zero-field cooled and field cooled DC magnetization measurements (bifurcation and blocking temperature), as well as M(H) hysteresis (below and above the blocking temperature) lead us to initially suggest that the material may in fact be superparamagnetic. However, further investigation of the real AC susceptibility …

Computational Modeling Studies Of The Structures And Properties Of Organotin(Iv) And Stannyl-Thioether Systems With Comparisons To X-Ray Crystallography, Michelle R. Stem Joseph

Open Access Theses & Dissertations

Controlling the toxic effects of organotin(IV) compounds involves engineering the structure of the molecules to optimize their properties. Molecular engineering, coupled with improved capabilities to generate reliable computational optimization models (COMs), will enable researchers to have greater success at harnessing the highly specific cytotoxicity of organotins. For example, as the thio_n ligand phenyl groups were replaced with Cl atoms, the S-Sn intramolecularity was strengthened, the bond distance decreased, and the stannyl tetrahedral structure was deformed from its triphenyl conformation. With each substitution, conformation deformations lowered the damaging bioactivity levels of thio_n. Bonding various ligands to organotin(IV) compounds …

A Study Of The Interaction Of Thioindigo Dye, With Several Inorganic Host Materials, Alejandra Ramirez

Open Access Theses & Dissertations

Maya Blue has been the focus of numerous studies and is believed to be a mixture of palygorskite clay and indigo dye.^1,2 Several derivatives of this pigment have been developed with intriguing properties. For instance, the dye thioindigo reacts with the palygorskite clay to exhibit a broad range of colors from red to blue under UV-Vis excitation. Based on FT-Raman and computer simulation, previous work performed in our group could relate indigo and thioindigo interaction to the aluminum sites in the framework. super>3,4

The work performed with other inorganic host materials such as, layer structures and zeolites have …