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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 …

Strontium Monoxide Measurements In Methane-Air Flames, Bobby J. Wimberly

Masters Theses

The spectroscopy of alkaline earth metal compounds has been an area of active research for several decades. This is at least in part stimulated by the application of these compounds to practical areas ranging from technology to medicine. The use of these compounds in the field of pyrotechnics was the motivation for a series of flame emission spectroscopy (FES) experiments with strontium containing compounds. Specifically, strontium monoxide (SrO) is studied as a candidate radiator for the diagnostic of methane-air flames.

SrO emissions have been observed in flames with temperatures in the range of 1200-1600-K for two compounds: strontium hydroxide and …

Reflectance And Emission Spectroscopy: Curve Fitting Methods With Application To Impact Glasses And The Varying Grain Size Of Planetary Analogue Minerals, Michael A. Craig

Electronic Thesis and Dissertation Repository

Spectroscopy, i.e., the measurement of electromagnetic radiation as a function of wavelength, is arguably the technique most responsible for the majority of what is collectively known about the composition of stars, the distances to galaxies, the age of the universe and so on. Spectroscopy is also the tool most used to discern the mineralogy of planetary bodies remotely. Measuring the speed at which a star is receding and its composition, or the composition of an interstellar cloud of gas are well understood uses of spectroscopy. When it comes to spectroscopies use to discern mineralogy, the scientific literature on the subject …

Low Intensity Gamma-Ray Spectroscopy Of The Lake Labyrinth Meteorite, Tristan C. Paul

Physics

A 23.7g fragment of the Lake Labyrinth Meteorite (fell in 1924, collected in 1934 at Lake Labyrinth in South Australia, Australia) was re-investigated for evidence of the presence of 98Tc using a two dimensional low-intensity gamma-ray spectrometer. A new calibration technique using 26Al sources found the gamma-rays previously thought to be due to 98Tc are more likely from 166Ho. The presence of 166Ho is most likely due to activation of the stable 165Ho in the meteorite from terrestrial background sources where it was stored.

Empirical Measurement And Model Validation Of Infrared Spectra Of Contaminated Surfaces, Sean Archer

Theses

The goal of this thesis was to validate predicted infrared spectra of liquid contaminated surfaces from a micro-scale bi-directional reflectance distribution function (BRDF) model through the use of empirical measurement. Liquid contaminated surfaces generally require more sophisticated radiometric modeling to numerically describe surface properties. The Digital Image and Remote Sensing Image Generation (DIRSIG) model utilizes radiative transfer modeling to generate synthetic imagery for a variety of applications. Aside from DIRSIG, a micro-scale model known as microDIRSIG has been developed as a rigorous ray tracing physics-based model that could predict the BRDF of geometric surfaces that are defined as micron to …

Spectroscopy And Photophysics Of Carotenoids In Solution And In Light-Harvesting Pigment-Protein Complexes, Nikki Cecil M. Magdaong

Doctoral Dissertations

This thesis examines the factors affecting the photophysics and energy transfer properties of carotenoids. Steady-state and ultrafast time-resolved spectroscopic experiments were carried out on several carotenoids in various solvents and light-harvesting pigment-protein complexes. The main goal is to probe the excited state properties and kinetics of these molecules and relate the findings to their roles in light-harvesting and photoprotection of the photosynthetic apparatus. The spectroscopic studies on a short conjugated peridinin analogue extends previous studies on synthetic peridinin analogues having different numbers of conjugated carbon-carbon double bonds. The results provide insight into the nature of the intramolecular charge transfer state …

Solubility And Detectability Of Hydrocarbons On The Surface Of Titan, Sandeep Singh

Graduate Theses and Dissertations

Titan’s thick atmosphere is enriched with organic compounds and its surface holds reservoirs of hydrocarbons. This makes Titan the only other candidate in our solar system (apart from Earth) to have stable liquid at the surface. The stability and characteristics of liquid and ices on the surface of Titan are of high importance in understanding its surface-atmosphere interactions. Titan’s hydrological cycle is similar to what we see on Earth, with the exception of methane (CH4) and ethane (C2H6) taking the place of water. The smoggy atmosphere veils the surface of Titan from the view of Cassini spacecraft, except at seven …

Spectroscopic, Imaging, And Doping Studies Of Push-Pull Conjugated Polymer Solar Cells, Eric Jeri Jon Martin

Nanoscience and Microsystems ETDs

Organic Photovoltaics (OPV) have the potential to provide inexpensive, renewable electric power to satisfy increasing global energy demands due to their low materials and processing costs. Poly[2,6-(4,4-bis-(2-ethylhexyl)-4H-cyclopenta [2,1- b;3,4-b\u2032]dithiophene)-alt-4,7(2,1,3-benzothiadiazole)] (PCPDTBT) is a promising candidate for use in solar cell active layers, and has produced OPV devices with power conversion efficiencies (PCEs) exceeding 5% when blended with fullerene electron acceptors. Although these results are encouraging, a molecular-level understanding of photophysical processes involved in photocurrent production is needed to propel the use of PCPDTBT and other conjugated molecules into widespread use in solar cells. The research presented herein is aimed at improving …

Coupling Nuclear Induced Phonon Propagation With Conversion Electron Mössbauer Spectroscopy, Michael J. Parker

Theses and Dissertations

Mössbauer spectroscopy is a very sensitive measurement technique (10^-8 eV) which prompted motivation for the experiment described in this thesis. Namely, can a sensitive detection system be developed to detect nuclear recoils on the order of 10 to 100 of eVs? The hypothesis that this thesis tests is: Nuclear induced phonon bursts caused by Rutherford scattered alphas, decayed from ²⁴¹Am, in a type-310 stainless steel material can couple with 7.3 keV conversion electron Mössbauer events at the other end of the material which will have a statistically significant effect on a Mössbauer spectrum. The phonon bursts produced by …

Effects Of Acute And Chronic Hypoxia On Respiratory Physiology Of Paddlefish (Polyodon Spathula), Daniel Larbi Aboagye

Theses and Dissertations

Among the basal bony fishes, the American paddlefish (Polyodon spathula) has a unique respiratory strategy of ram-ventilation. However, despite the increasing problems caused by hypoxia in natural habitats occupied by this species, little information exists about their response to hypoxia. Four studies were conducted to examine the physiological and biochemical responses of juvenile paddlefish (150-181 g) to acute and chronic hypoxia. Acute hypoxia tolerance, aerobic metabolic rates and swimming capabilities of paddlefish in an intermittent respirometer or swim flume were evaluated under normoxic (partial pressures of oxygen [pO2] =140 mm Hg) and hypoxic (pO2 =62 mm Hg) conditions at 18 …

Differentiation Of Human, Animal And Synthetic Hair By Atr Ftir Spectroscopy, Jeremy Manheim

Chemistry

Hair fibers are ubiquitous to every environment and are the most commonly found form of trace evidence at crime scenes. The primary difficulty forensic examiners face after retrieving a hair sample is determining who it came from. Currently, the methodology of microscopic examination of potential hair evidence is absent of statistical probability and is inherently subjective. Another method, involving DNA analysis, takes months to conduct and the majority of times is unsuccessful due to its degradation and absence from the hair. Here, Attenuated Total Reflectance (ATR) Fourier Transform Infrared (FTIR) Spectroscopy coupled with advanced statistics was used to identify a …

Spectroscopy Of States With Ion-Pair Character Near Rb(5s)+Rb(4d), Marco Ascoli

Doctoral Dissertations

Molecular and Rydberg physics have separately enjoyed, in the last decade or so, an enormous expansion due to the application of laser cooling techniques that allow control and resolution previously unattainable. One feld that lies at the intersection has not yet bene?ted from this development: heavy Rydberg states. In this experimental work, I investigated the possibility of ion pair production in ultracold rubidium through confguration mixing.

Measuring The Hyperfine Splittings Of Lowest Energy Atomic Transitions In Rubidium, Benjamin D. Graber

Undergraduate Honors Thesis Projects

The goal of this experiment was to measure the hyperfine energy splittings of the ground to first excited state transitions in rubidium using saturated absorption spectroscopy. Using this technique, we measured these transition energy spectra by taking the difference of two photodiode outputs due to multiple beams of a single laser scanned over a range of frequencies and shone through a cell of Rb vapor. When the laser frequency was resonant with an atomic transition, photons of those frequencies were absorbed, leaving a dip in intensity of the beam measured at the photodiode. One of the two laser beams had …

Mueller Matrix Spectroscopic Ellipsometry Of Multiferroics, Roman Basistyy

Dissertations

Multiferroics, materials which possess several ferroic orders, are the focus of research in recent years. Among these materials are oxide crystals, such as, for example, RMnO₃, RMn₂O₅, R₃Fe₅O₁₂, where R stands for rare earth ions. The most fascinating physics occurs when magnon-lattice coupling reveals itself in the far-IR spectra of multiferroics. The expected optical behavior puts multiferroics into a more general category of bi-anisotropic materials, the properties of which could be only described using anisotropic dielectric ε(ω), magnetic μ(ω), and …

Nucleation And Detection In Tension Metastable Fluids, Thomas Francis Grimes

Open Access Dissertations

Neutron detection and spectroscopic techniques using state-of-the-art systems is covered. A novel approach using conventional (e.g., LiI, He-3, BF3) detectors coupled with Monte-Carlo code simulations to develop spectroscopy information was developed (in lieu of present-day tedious methods involving data acquisition using a multi-sized set of Bonner spheres). Focus of this thesis work was on developing neutron spectroscopy and multiplicity technology using the underlying science of tensioned metastable fluid detectors (TMFDs) in which neutron radiation interactions with atoms of TMFD fluids cause onset of cavitation bubbles. There are many applications and areas of science that would benefit from an increased knowledge …

A 21st Century Investigation Of The Lightning Spectrum, Thomas Daniel Walker

Dissertations

In the mid 1960s, Martin Uman, Leon Salanave and Richard Orville laid the foundation for lightning spectroscopy. They were among the first to acquire time re- solved return stroke spectra and the first to use spectroscopy as a diagnostic technique to characterize physical properties of the lightning channel [1] [2] [3]. Now, almost 50 years later, technology, including CMOS and CCD high speed cameras, volume-phase holographic (VPH) gratings, and triggered lightning, has progressed to the point at which new studies in lightning spectroscopy are needed to verify and extend past measurements. New spectral lines have been discovered in the lightning …

Terahertz Spectroscopy Of Magnetic Metal Oxides, Evan Constable

University of Wollongong Thesis Collection 1954-2016

The optical excitation and control of spins in magnetic materials promises new avenues for devices that couple photonic and spintronic functionality, with the prospects of a new paradigm in information processing. An understanding of the behaviour of the magnetic interactions in candidate materials is essential to the design of devices that exhibit these desirable properties. Terahertz radiation presents an ideal medium for the study of spin dynamics in magnetic materials. Its low energy in the meV range is equivalent to the many weak magnetic coupling mechanisms present. Terahertz radiation is therefore also complementary to established methods that probe these mechanisms …

Synchrotron Based Infrared Microspectroscopy Of Carbonaceous Chondrites., Mehmet Yesiltas

Electronic Theses and Dissertations

Relationships between organic molecules and inorganic minerals are investigated in five carbonaceous chondrites, Northwest Africa 852 (CR2), Tagish Lake (C2-ungroupped), Orgueil (CI1), Sutter's Mill (CM), and Murchison (CM2), with micron spatial resolution using synchrotron-based imaging micro-FTIR spectroscopy. Correlations based on absorption strength for various constituents are determined using statistical correlation analysis. Silicate band is found to be positively correlated with stretching modes of aliphatic hydrocarbons in NWA 852 and Tagish Lake. The former is highly correlated with the hydration band in all meteorites. Negative correlation is observed between water+organics and carbonate bands in all meteorites. Two dimensional infrared maps for …

The Spectroscopic Characterization Of Newly Developed Emissive Materials And The Effects Of Environment On Their Photophysical Properties, Louis Edward Mcnamara

Electronic Theses and Dissertations

The development of new materials capable of efficient charge transfer and energy storage has become increasingly important in many areas of modern chemical research. This is especially true for the development of emissive optoelectronic devices and in the field of solar to electric energy conversion. The characterization of the photophysical properties of new molecular systems for these applications has become critical in the design and development of these materials. Many molecular building blocks have been developed and understanding the properties of these molecules at a fundamental level is essential for their successful implementation and future engineering. This dissertation focuses on …

Characterization Of Alabama Red Wine By Hplc And Multiple Spectroscopy Methods, Kayla Helene Smith

Theses

The purpose of this work was to conduct a chemical characterization on a local Alabama wine using Ultraviolet-visible Spectroscopy, Atomic Absorbance Spectroscopy, Infrared Spectroscopy, and High Performance Liquid Chromatography to determine whether characteristics of the wine were altered throughout the clarification process. The analyzed samples consisted of a freshly pressed grape, processed grapes inclusive of the addition of sulfites, and a store ready bottle of a Muscadine sweet red wine. A Ferrozine Assay, used to determine antioxidant activity, indicated that the newest freshly pressed sample had the greatest amount of health benefiting antioxidants. The Atomic Absorbance revealed each sample to …

Investigating The Photorecombination Dynamics In Molecular High-Harmonic Spectra, Benjamin Parker Wilson

LSU Doctoral Dissertations

The work presented in this dissertation will relate the photorecombination dynamics to photoionization dynamics in SF6 utilizing the self-probing mechanism, high harmonic generation (HHG). This work specifically aims to establish parameters for which the comparison is applicable and the macroscopic complications inherent in HHG do not interfere with the extraction of dynamic information. The first part of this work established the macroscopic experimental apparatus necessary for consistent spectroscopic observation. It is shown that using a gas jet that is an order of magnitude shorter than the Rayleigh length of the driving laser results in more consistent harmonic spatial profiles and …

Photoelectrons And Recombining Electrons In Atomic And Molecular Systems, Kristen D'Ann Fulfer

LSU Doctoral Dissertations

This work in this dissertation explores how photoelectrons enter and exit atoms and molecules. The electron rescattering events which may occur during photoionization or photorecombination processes play a dominant role in the understanding of how photoelectrons enter and exit molecules, which is intrinsically linked to how chemical reactions occur. Chapters 3-4 of this dissertation present evidence of vibrational mode specific breakdown of the Franck-Condon Principle in the photoionization of low symmetry molecules, acrolein and the singly halogenated thiophenes, due to resonant and non-resonant electron rescattering dynamics. In Chapters 5-6, the disentanglement of the valence electronic structure, as well as evidence …

Pulsed Inductive Plasma Studies By Spectroscopy And Internal Probe Methods, Warner C. Meeks

Doctoral Dissertations

The broad effort of the Missouri Plasmoid Experiment is to elucidate the energy conversion processes in a pulsed inductive discharge due to the presence of plasma. The test article is a 440 to 490 kHz theta-pinch (or solenoidal) geometry coil with a stored energy of around 80 joules. In this work experimental hydrogen, helium, argon and xenon data at back-fill pressures of 10 to 100 mTorr (1.3 to 133.3 Pa) are obtained and interpreted. Spectral and internal probe studies were performed on MPX Mk.I and Mk.II devices, respectively. IR spectra were acquired in the Mk.I device for argon and xenon. …

An Experimental Method Of Measuring Spectral, Directional Emissivity Of Various Materials And Joule Heating, Robert Bickel

Theses and Dissertations--Mechanical Engineering

Emissivity is an important parameter in calculating radiative cooling of a surface. In experiments at the NASA Ames hypervelocity ballistic range, one of the main errors indicated in temperature measurements is the uncertainty of emissivity for the materials under investigation. This thesis offers a method for measuring emissivity of materials at elevated temperatures at the University of Kentucky. A test specimen which consists of different sample materials under investigation and a blackbody cavity was heated in a furnace to an isothermal condition at known temperature. The emitted thermal radiation was measured and the comparison of sample and blackbody radiation yielded …