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 …

Non-Destructive Determination Of Magnetic Audio Tape Degradation For Various Tape Chemistries Using Spectroscopy And Chemometrics, Alyssa Marie Abraham

Theses and Dissertations

This dissertation focuses on creating a non-destructive method for the identification of degraded magnetic audio tapes using attenuated total reflectance Fourier transform infrared spectroscopy (ATR FT-IR) and chemometrics. The primary recording medium during the second half of the twentieth century was magnetic tapes. These tapes hold some of the world’s modern cultural history. Unfortunately, the majority of these tapes were made with a polyester urethane (PEU) binder, which has shown to degrade through hydrolysis of the ester component, called sticky shed syndrome (SSS). As the name implies, degraded tapes will stick and shed onto player guides and heads during playback. …

Optimized Spectral Processing Of Infrared Diffuse Reflection Spectra For The Detection Of Blood On Fabric, Stephanie Ann Dejong

Theses and Dissertations

The detection of bodily fluids such as blood on interfering backgrounds is important to the forensic community. Luminol, which participates in a chemiluminescent reaction with the heme groups of blood, is one of the most commonly used presumptive tests. Luminol has a few drawbacks, including the requirement of use in a dark environment and potential to degrade the amount of recoverable DNA in blood stains. A potential complementary method is infrared (IR) spectroscopy. These two methods are compared in this work. Infrared diffuse reflection (DR) spectroscopy works well to measure the IR spectrum of samples that are highly absorbing or …

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 …