Physical Sciences and Mathematics Commons^™

Characterizing Molecular Environments In Acrylic Paint Via Single-Sided Nmr, Lyndi Kiple

Dissertations, Theses, and Masters Projects

Acrylic paint is a modern artistic material made of colored pigment and polymeric binder. Acrylic binder requires fundamental study at the molecular level to understand its physical properties for purposes of art conservation and general polymer chemistry. The research presented in this thesis uses single-sided nuclear magnetic resonance (NMR) as a non-invasive and non-destructive way to measure relaxation and self-diffusion, which provide insight to molecular mobility and physical properties of proton-containing samples. Specifically, this study relies on T2 relaxation to gain insight to regions within acrylic paint with different molecular mobilities. In both dry and wet paint, relaxometry data revealed …

Gas-Phase Proton Affinities For Twenty Of The Proline-Containing Dipeptides, Henry Cardwell

Undergraduate Honors Theses

Peptide fragmentation plays a crucial role in the analysis of proteins through mass spectrometry-based proteomics. Most proteomics experiments take place in the low-energy regime and are governed by the mobile proton model which predicts random cleavages along the peptide backbone; however, there sometimes arise circumstances where the mobile proton model fails causing sequencing algorithms to misidentify peptides. One such example is noted in the “proline effect” wherein proline-containing peptides preferentially fragment N-terminal. While it has been established that the “proline effect” is due to the rigidity and basicity of the proline N-terminus, a further understanding of the factors influencing the …

Exploring The Photophysics Of Brown Carbon Chromophores Using Laser-Based Spectroscopy And Computational Methods, Megan Elizabeth Alfieri

Dissertations, Theses, and Masters Projects

Atmospheric aerosols are made up of suspended liquids and solids in the atmosphere. These aerosols play a very important role in the solar energy exchange in Earth’s atmosphere as well have dramatic impact on human health. Different aerosols have different effects on the atmosphere depending on the physical properties of the aerosols.

The purpose of this research project is to understand how the structure of molecular chromophores impacts the solar absorption properties of aerosols. We propose a series of laboratory studies to investigate the outcomes from solar absorption of brown carbon chromophores: 1-phenylpyrrole, 2-phenyl-1-H-pyrrole, 2-phenylimadazole, as well as water complexes. …

Investigating Charge Transfer Complexes In Brown Carbon Aerosols, Brianna Peterson

Undergraduate Honors Theses

Aerosols are suspensions of particles in the air, commonly seen as dust or fog in the atmosphere. Brown carbon is a particular classification of carbonaceous atmospheric aerosol that increases in absorption from the visible to ultraviolet region, making it important for radiative forcing models. Elucidating the structures of brown carbon chromophores has been difficult as brown carbon is a broad category and the chromophore type can change depending on emission source, temperature, humidity, and season. Twisted intramolecular charge transfer (TICT) molecules have been identified as potential brown carbon chromophores. TICT molecules are those that allow charge transfer to occur between …

Investigating The Electron Transfer Dynamics Of Eosin Y Photosensitizers Using Single Molecule Spectroscopy, Kelly Margaret Kopera

Dissertations, Theses, and Masters Projects

Growing global energy demands have necessitated the search for alternative sources of renewable fuels. Dye-sensitized photocatalysis (DSP) is a promising low cost, sustainable method that directly converts solar energy to readily usable forms of energy such as hydrogen fuel. While DSP is a promising technology, its efficiency is limited by back electron transfer and kinetic redundancy. In order to fully understand these processes, single-molecule spectroscopy (SMS) is used to probe the electron transfer (ET) dynamics of photosensitizers. In particular, eosin Y (EY), a brominated fluorescein derivative that undergoes intersystem crossing prior to injection, is investigated using SMS. In this approach, …

Surface-Enhanced Raman Spectroscopy Studies Of Organic Dyes For Art Conservation And Ph Sensing Applications, Shelle Nicholle Butler

Dissertations, Theses, and Masters Projects

Surface-enhanced Raman scattering (SERS) spectroscopy is a powerful analytical technique with widespread applications. In this work, SERS applications in the realms of art conservation and biosensing are reviewed. First, the theory of this unambiguous and ultrasensitive technique is explained. Next, a review of the pedagogical journey in art conservation research through the lenses of undergraduates is offered in Chapter 2, a chapter recently submitted to the American Chemical Society. Finally, an investigation in biosensing SERS is explored with developing a SERS pH sensitive probe while offering new insight into SERS capabilities and the relationship between analyte and nanoparticle.

Gas-Phase Thermochemical Properties Of Proline-Containing Dipeptides And Fluorinated Alcohols Using The Extended Kinetic Method, Kathy Tang Huynh

Dissertations, Theses, and Masters Projects

No abstract provided.

Advanced Topographic Characterization Of Variously Prepared Niobium Surfaces And Linkage To Rf Losses, Chen Xu

Dissertations, Theses, and Masters Projects

Superconducting radio frequency (SRF) technology is widely adopted in particle accelerators. The shallow penetration (∼ 40 nm) of the RF into superconducting niobium lends great importance to SRF cavity interior surface chemistry and topography. These in turn are strongly influenced by the chemical etching "surface clean-up" that follows fabrication.;The principal surface smoothing methods are buffered chemical polish (BCP) and electropolish (EP). The resulting topography is characterized by atomic force microscopy (AFM). The power spectral density (PSD) of AFM data provides a more thorough description of the topography than a single-value roughness measurement. In this work, one dimensional average PSD functions …

Polymeric Radiation Shielding For Applications In Space: Polyimide Synthesis And Modeling Of Multi-Layered Polymeric Shields, Clinton Cleveland Schiavone

Dissertations, Theses, and Masters Projects

No abstract provided.

Thermochemistry Of Amino Acids And Constrained Diamines, Erica Jane Tullo

Dissertations, Theses, and Masters Projects

The gas-phase proton affinities of several highly basic amino acids and diamines were determined using the extended kinetic method in an ESI-quadrupole ion trap instrument. The non-protein amino acid L-canavanine is structurally related to L-arginine with an oxygen substituted for the terminal methylene group of L-arginine and is highly toxic to humans. The proton affinity of L-arginine, a protein amino acid, was determined to be 1036 kJ mol -1, whereas the proton affinity of L-canavanine was determined to be 1005 kJ mol-1. Thus, substitution of an oxyguanidino group for the guanidine group in L-arginine results in a large decrease in …

Surface Study Of Niobium For Superconducting Radio Frequency (Srf) Accelerators, Hui Tian

Dissertations, Theses, and Masters Projects

Niobium rf superconductivity is a near-surface phenomenon because of the shallow rf penetration depth. Accordingly, the performance of Nb SRF accelerator cavities is strongly impacted by the topmost few nanometers interior surface, especially as impacted by the final surface conditioning treatments.;Surface topography impacts performance through local loss of superconductivit caused by intrusion of the rf magnetic field, which is enhanced at sharp protrusions. "Sharpness" comprises both vertical and lateral aspects, requiring development a new characterization approach beyond the familiar roughness measurements (Ra, Rz), which view only the vertical component. Stylus profilomety and atomic force microscopy traces view surface topography from …

The Photochemistry Of Thiobenzoyl Derivatives Of Methyl Benzylidene-Alpha-D-Glucopyranoside, Adam Louis Schreiber

Dissertations, Theses, and Masters Projects

No abstract provided.

The Selective Oxidation Of Beta-Cyclodextrin On The Secondary Face, Christine Evelyn Heath

Dissertations, Theses, and Masters Projects

No abstract provided.

Analysis Of The Electronic Kinetic Energy In Xenon Difluoride, Michael Fiore Amendola

Dissertations, Theses, and Masters Projects

No abstract provided.

Effects Of Electron Irradiation And Percent Composition On The Glass Transition Temperature And Damping Of Boron-Epoxy Composites, Ian Ivan Nieves

Dissertations, Theses, and Masters Projects

No abstract provided.

Acid Dissociation Of Chloroguaiacols And Ph Dependent Sorption To Estuarine Sediments, Jennifer Lisa Gundersen

Dissertations, Theses, and Masters Projects

Chloroguaiacols are common components of bleached kraft pulp mill effluent known to bioaccumulate in aquatic organisms, and sorb onto particulate material and sediments. Ionization properties of the chloroguaiacols must be known in order to explain their sorptive behavior in aquatic systems. to obtain this information, thermodynamic acid dissociation constants (p&K\sb{lcub}\rm a{rcub})& of guaiacol (o-methoxyphenol) and nine chloroguaiacols have been determined by spectrophotometric methods. These experimental p&K\sb{lcub}\rm a{rcub}& values have been compared with literature values, values predicted by the Hammett equation and predictions by quantum chemical calculations using MOPAC 6.0 with AM1 and MNDO Hamiltonian operators. Experimental and predicted acidities were …

First Principles Linear Response Calculations Of Lattice Dynamics, Cheng-Zhang Wang

Dissertations, Theses, and Masters Projects

First principles calculations, using the density-functional theory and particularly the local density approximation (LDA), have achieved remarkable success in studying the properties of solid state systems. Although the basic results of these calculations are the electronic structures (eigenvalues, eigenfunctions, etc.) and the total energy of ground state, many other related physical properties can be deduced from them by investigating their response under external perturbations. Using the linear response method with linearized-augmented-plane-wave (LAPW) basis, we have calculated lattice dynamical properties of important semiconductors CuCl, SiC and ferroelectric KNbO{dollar}\sb3.{dollar} CuCl is known to exhibit large anharmonic effects and possibly a complicated multi-well …

Mechanisms Of Poly(Vinyl Chloride) Pyrolysis In The Presence Of Transition Metals, William Stephen Bryant

Dissertations, Theses, and Masters Projects

No abstract provided.

Deuteron Nuclear Magnetic Resonance Studies Of Molecular Motion In Solids, Tak Yan Tse

Dissertations, Theses, and Masters Projects

$\sp2$H-NMR is a powerful spectroscopic technique for investigating dynamics in solids. to extend the range of motional rates that can be quantitatively investigated, a new approach for measuring the quadrupolar spin-lattice relaxation time $T\sb{1Q}$ was developed. This uses a Broadband Jeener-Broekaert (BBJB) sequence with echo-detection, which avoids the frequency-discriminated excitation profile and spectral baseline distortion intrinsic to the conventional Jeener-Broekaert (JB) experiment. By combining the BBJB experiment with an Inversion-Recovery sequence with Quadrupole-Echo detection (IRQE), two independent longitudinal relaxation times, $T\sb{1Q}$ and $T\sb{1Z}$, can be measured. Spectral densities of motion $J\sb1(\omega\sb{o}$) and $J\sb2(2\omega\sb{o}$) are extracted from these relaxation times. The …

Dielectric Relaxation In Controlled Pore Glass, David Brian Faddis

Dissertations, Theses, and Masters Projects

No abstract provided.

In Situ Dielectric Monitoring And Kinetic Analysis Of Phase Separation, Theodore Joon Kim

Dissertations, Theses, and Masters Projects

No abstract provided.

Dielectric Monitoring Of The Chemical, Rheological, And Morphological Changes Incurred During Cure Of Epoxide-Amine Systems, Dara Elyn Levy

Dissertations, Theses, and Masters Projects

No abstract provided.

Aqueous Solubility Of Liquid Hydrocarbon Mixtures Containing Dissolved Solid Components, George G. Vadas

Dissertations, Theses, and Masters Projects

No abstract provided.

The Preparation Of And Upper Atmospheric Effects On Kevlar Films, Patricia Lynne Pate

Dissertations, Theses, and Masters Projects

No abstract provided.

Solid State Effects In The Reactions Of The Meta And Pura Trifluorodiazomethane/Beta-Cyclodextrin Inclusion Complexes, Shelley Hunnings Smith

Dissertations, Theses, and Masters Projects

No abstract provided.

The Cure Reaction Of An Aromatic Thermosetting Polyimide, Michael Edward Whitham

Dissertations, Theses, and Masters Projects

No abstract provided.

Thermodynamics And Kinetics Of Aqueous Solution Of Liquid Hydrocarbon Mixtures (Solutes, Petroleum), David Robert. Burris

Dissertations, Theses, and Masters Projects

Two-phase systems of a liquid hydrocarbon mixture, containing medium molecular weight (C(,7)-C(,12)) aromatic and aliphatic hydrocarbons, and water were examined in both equilibrium and kinetic experiments. Knowledge of the aqueous solution behavior of liquid hydrocarbon mixtures is of importance in determining the fate of hydrocarbon components in such systems of an environmental or geologic nature. Solute concentrations were determined by solvent extraction followed by gas chromatography. The equilibrium solute concentration for a given component i (C(,i)) is related to the pure compound solubility (C(,i)('o)), mole fraction of component i in the hydrocarbon phase (x(,i(h))) and the activity coefficient of component …

Acidic And Chemical Properties Of Molten Salt Hydrates, Stephen Keith Franzyshen

Dissertations, Theses, and Masters Projects

No abstract provided.

Dielectric Relaxation In The Uhf And Rf Regions, Theodore Bryant Kingsbury

Dissertations, Theses, and Masters Projects

No abstract provided.

The Measurement Of Flame Temperatures With Coated, Electrically Heated Thermocouples, Irvin Milton Miller

Dissertations, Theses, and Masters Projects

No abstract provided.