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Full-Text Articles in Physical Sciences and Mathematics

Oxidation Resistance Studies Of Crain Coatings On 430 Stainless Steel, Kurtis Wickey Jun 2008

Oxidation Resistance Studies Of Crain Coatings On 430 Stainless Steel, Kurtis Wickey

Honors Theses

The requirements of low cost and high-cost temperature corrosion resistance for interconnect plates in solid oxide fuel cell stacks has directed attention to the use of metal plates with oxidation resistant coatings. We have investigated the performance of stainless steel plates with homogenous coatings of CrAIN. The coatings were deposited using RF magnetron sputtering, with Ar as a sputtering gas and N as reactive gas. The Cr/A1 composition ratio in the coatings was varied in a combinatorial approach. The coatings were subsequently annealed in air for up to 25 hours at 800°C. The composition of the coated plates and the …


Hamiltonian Constraint Analysis Of Vector Field Theories With Spontaneous Lorentz Symmetry Breaking, Nolan L. Gagne Jan 2008

Hamiltonian Constraint Analysis Of Vector Field Theories With Spontaneous Lorentz Symmetry Breaking, Nolan L. Gagne

Honors Theses

Recent investigations of various quantum-gravity theories have revealed a variety of possible mechanisms that lead to Lorentz violation. One of the more elegant of these mechanisms is known as Spontaneous Lorentz Symmetry Breaking (SLSB), where a vector or tensor field acquires a nonzero vacuum expectation value. As a consequence of this symmetry breaking, massless Nambu-Goldstone modes appear with properties similar to the photon in Electromagnetism. This thesis considers the most general class of vector field theories that exhibit spontaneous Lorentz violation-known as bumblebee models-and examines their candidacy as potential alternative explanations of E&M, offering the possibility that Einstein-Maxwell theory could …


Diode Lasers For Use In Experiments On Cold Rydberg Atoms, Bill Whitledge Jan 2008

Diode Lasers For Use In Experiments On Cold Rydberg Atoms, Bill Whitledge

Honors Theses

This project was to measure the atomic density of (85)Rb atoms in a magneto optical trap using a low-intensity probe laser. Additionally, a dark spontaneous force optical trap was constructed in an attempt to boost the trap density. The dark spot failed to appreciably increase the overall trap density (which remained steady at - N = 10^10 atoms/cm^3) but it did increase the density of dark-state atoms in the trap by an order of magnitude. This is a useful result since many experiments on cold Rydberg atoms involve exciting atoms starting in the ground state rather than the first excited …


Interactions Of Electrons And Rydberg Atoms In Ultra-Cold Plasmas, Cristian Vesa Jan 2008

Interactions Of Electrons And Rydberg Atoms In Ultra-Cold Plasmas, Cristian Vesa

Honors Theses

This thesis discusses an experimental technique for investigating electron temperature control by Rydberg atoms in ultra-cold plasmas. The objective we set ourselves was twofold. Firstly, we sought to gain an insight into the processes whereby the creation of Rydberg atoms within the plasma lengthens the lifetime of the plasma. To this end, we created the plasma using a Littman dye laser and subsequently, at a variable time delay, we excited neutral atoms in the plasma to specific Rydberg states using a narrow bandwidth pulsed dye laser. Secondly, we employed radio-frequency (rf) electric fields to excite electron oscillations within the plasma …


Search For Novel Molecular Species Formed By Cold Rydberg Atoms In A Magneto-Optical Trap, Alexander Gill Jan 2008

Search For Novel Molecular Species Formed By Cold Rydberg Atoms In A Magneto-Optical Trap, Alexander Gill

Honors Theses

This describes a search for novel ultra-long-range molecular resonances between rubidium Rydberg atoms in a magneto-optical trap (MOT). We use the technique of photoassociative spectroscopy by directly scanning the wavelength of our Rydberg excitation laser about a 5p3/2 - 90p3/2 transition in a weak electric field and by scanning mm-waves about a 39sl/2 - 39p3/2 transition. The results of both of these surveys are inconclusive.