Physical Sciences and Mathematics Commons^™

Conservation Of Polyester-Urethane Magnetic Audio Tapes And Discrimination Of Textile Fiber Dyes Using Spectroscopy And Chemometrics, Nilmini Hemanthika Ratnasena

Theses and Dissertations

This dissertation explores and discusses conservation of magnetic audio tapes and discrimination of fiber dyes employing spectroscopic techniques and chemometrics.

Conservation of polyester urethane magnetic audio tapes has become a major challenge since they are susceptible to degradation via hydrolysis. The world’s modern cultural history is vastly recorded in this media, and now conservationists need a non-destructive technique to determine the playability status of these tapes. Once conservationists identify degraded tapes, they can be subjected to the baking process. This process temporarily reverses hydrolysis and provides enough time to digitize tapes, preserving information for future generations. The first three chapters …

A Spatial Heterodyne Spectrometer For Raman Imaging And Remote Spectroscopy, Ashley Nicole Allen

Theses and Dissertations

Raman and Laser-Induced Breakdown Spectroscopy (LIBS) are optical techniques that provide information about the chemical makeup of a sample without any preparation or physical contact with it. For this reason, Raman and LIBS spectrometers are among the instruments selected for NASA’s Mars 2020 rover mission and are being considered for future missions to the Jovian moons, asteroids and comets. Such future missions will require smaller, more ruggedized Raman and LIBS spectrometers, and the new type of spectrometers discussed here, the spatial heterodyne Raman and LIBS spectrometers are being developed for this purpose. The SHS is a wide-field, Fourier transform, stationary …

Issues In Laser Induced Breakdown Spectroscopy For Measurements In The Deep Ocean And Other High-Pressure Environments, Joseph C. Bonvallet

Theses and Dissertations

This dissertation describes fundamental and applied studies that have advanced the understanding and application laser induced breakdown spectroscopy (LIBS) to the deep-ocean environment and to operation on a deep-ocean submersible. Chapter one is an overview of LIBS including a brief history, LIBS theory, the instrumentation typically used, and a specific application. Chapter two analyzes the effect that monodisperse suspended particles have on LIBS emission intensity and on the formation of a LIBS plasma. This chapter demonstrates that for particle concentrations similar to those found in the neutrally buoyant regions around hydrothermal vents there is little effect on the LIBS emission …

Optical Spectroscopy And Chemometrics For Discrimination Of Dyed Textile Fibers And Magnetic Audio Tapes, Nathan C. Fuenffinger

Theses and Dissertations

This dissertation focuses on the application of both novel and standard chemometric approaches toward societal problems of interest in the areas of forensic science and cultural heritage preservation. Microspectrophotometry (MSP), a technique enabling measurements of absorption of electromagnetic radiation by microscopic materials in the ultraviolet-visible (UV-Vis) region, is widely used by forensic examiners for comparisons of metameric textile fibers. These comparisons are often hindered, however, by the raw or normalized spectra showing little detail or having few points of comparison. Derivative preprocessing can enhance structure in some instances. We have demonstrated through the use of multivariate statistics that derivatives are …