Physical Sciences and Mathematics Commons^™

Evaluation Of Raman Spectroscopy And Ruby Piezospectroscopy As Tools For Investigating The Corrosion Of Metallic Alloys, Daniel P. Renusch

Dissertations

Stainless steel system components that operate in high temperature oxidizing environments obtain protection from corrosion by means of thermally grown chromia and alumina scales. Ongoing investigations of protective scales utilize a battery of experimental and theoretical techniques. A technique which has received little attention is Raman scattering. The reason for its limited use has been long data acquisition times required to obtain suitable spectra from thin surface oxides. Because advances in detection systems, namely the multichannel CCD (charge coupled devices), have recently provided dramatic improvement in the sensitivity of Raman scattering experiments, we decided to reevaluate the technique as a …

A Comprehensive Approach For Evaluation Of Groundwater Vulnerability To Contamination, Shafiul H. Chowdhury

Dissertations

Groundwater vulnerability to contamination from surface sources was evaluated for Nottawa Creek Watershed, Calhoun County Michigan using AQUIPRO and DRASTIC vulnerability methods. A geographic information system (GIS) was used to analyze and map the data. Forty groundwater samples were collected following a statistical sampling protocol from private wells. Samples were analyzed for nitrate-N and atrazine. Atrazine was not detected (detection limit 0.1 ppb) in any of the samples. Five samples contained detectable nitrate-N (detection limit 0.05 mg/L). Due to insufficient chemical data, the relative AQUIPRO and DRASTIC vulnerability scores could not be compared with the frequency of occurrences o f …

Periodicity And Disorder, Simeon D. Simeonov

Dissertations

We have studied four examples of periodicity and disorder in nature and the phenomena associated with them.

In the first chapter of the dissertation we present an introduction to this work.

In the second chapter, the photonic band structures of two types of zinc blend structures are computed using the plane wave expansion method. Both structures are formed from an array of dielectric spheres in a vacuum background. In a first type zinc blend structure the spheres have the same size but different dielectric constants. In a second type of structure we keep the dielectric contrast of the spheres the …