Engineering Commons^™

Synthesis And Development Of Boron Nanotubes And Metal/Ceramic-Carbon Nanotube Composites, Jinwen Liu

Dissertations

The first part of this thesis will be focused on developing a facile and scalable solid — solid chemical vapor deposition (CVD) process using a solid boron precursor to synthesize crystalline boron nanotubes (BNTs) mixed with small amounts of boron nanofibers (BNFs). The synthesis involves the use of solid boron precursors - magnesium boride and magnesium borohydride, magnesium and nickel boride as co-catalysts, and porous MCM-41 zeolite as the growth template. Experimental parameters, such as temperature, grinding of constituents and starting precursor-catalyst-template compositions, were studied and optimized. Detailed characterization have been carried out using field-emission scanning electron microscopy (FE-SEM), transmission …

A Study Of Three Transition Metal Compounds And Their Applications, Zhen Qin

Dissertations

The La_5/8-yPr_yCa_3/8MnO₃ with colossal magnetoresistance (CMR) effect has a rich phase diagram and is well studied for its electronic phase separation phenomenon, where the ferromagnetic (FM) metal order co-exists and competes with the charge-ordered (CO) insulator phase. High Pr doping will favor the CO order, leading a sharp FM to CO dominated phase transition around Pr concentration of 0.3 and above. Hydrostatic pressure favors FM metallic order without damaging the sample and can be tuned continuously. In this study, pressurized-magnetic and resistivity measurements was done on a La_0.25Pr_0.375Ca_{0.375 …}

Study Of Mechanisms Of Phytotoxicity Of Alumina Nanoparticles, Anthony Elijius

Dissertations

Plant growth inhibitory effect of alumina nanoparticles has recently been reported (Ling Y, Watts D, 2004) but the mechanisms of such an effect are yet to be established. The phytotoxicity of aluminum and some of its compounds is well known, but the rapid expansion of nanotechnology resulting in the introduction of new sets of materials in the nanometer range has led to the development of new approaches, experimental methods and modes of investigation.

In this study, the observed phytotoxic effects of alumina nanoparticles suspension on five plant species (Zea mays, Cucumis sativus, Daucus carota, Brassica oleracea, Lactuca sativa) …

Mixing Of Nanosize Particles By Magnetically Assisted Impaction Techniques, James V. Scicolone

Dissertations

Nanoparticles and nanocomposites offer unique properties that arise from their small size, large surface area, and the interactions of phases at their interfaces, and are attractive for their potential to improve performance of drugs, biomaterials, catalysts and other highvalue- added materials. However, a major problem in utilizing nanoparticles is that they often lose their high surface area due to grain growth. Creating nanostructured composites where two or more nanosized constituents are intimately mixed can prevent this loss in surface area, but in order to obtain homogeneous mixing, de-agglomeration of the individual nanoparticle constituents is necessary.

Due to high surface area, …

New Media Icc Profiles Construction And Concerns, Reem El Asaleh

Dissertations

With the advent of the modern digital technology, users can now capture an image and reproduce it between different media, such as display it on LCD monitor or tablet computer, print it on desktop printer or send it to a printing press. The challenge has been then to maintain the accuracy of image colors during this reproduction, which has led to the development of Color Management Systems. Using these systems, the color reproduction across-media will be accomplished using device ICC profiles that describe each device’s color characterization data in a standardized format based on International Color Consortium (ICC) specifications.

ICC …