Synthesis of Cross-Conjugated Dibenzochrysene-Based Photosensitizers for Dye-Sensitized Solar Cells

Dye-sensitized solar cells (DSCs) represent a promising alternative method of energy generation. Absorbance of light across the visible spectrum and into the near-infrared (NIR) region is crucial to increasing the power conversion efficiencies (PCEs) of DSC devices. Dye absorbance can be red-shifted by either increasing the conjugation path of the photosensitizer or by increasing the strength of electron donors and acceptors found in molecules. By using a polycyclic aromatic π-bridge in a dye, lower energy wavelengths of light can be absorbed. Dibenzochrysene is a six-ring polycyclic aromatic hydrocarbon (PAH) with substitutable positions that allow for a double-donor, double-acceptor (DD-π-AA) structure, in which both donors and both acceptors contribute to the electronic properties of the structure. This under-utilized dye structure benefits from the additive electron donation strength provided by two donor groups, allowing for a narrowed optical band gap and deeper absorbance into the NIR region. Additionally, the usage of two anchoring groups creates dye molecules that bind tightly to metal oxide semiconductors and leads to more stable solar devices. To date, several synthetic strategies have been attempted towards the creation of these types of dyes

Mechanochemical and Combustion Syntheses of Cerium-Doped Lutetium Oxyorthosilicate Powders and Preliminary Studies into the Syntheses of Optically-Active Beta-Germanium(IV) Oxide and Alpha-Quartz Nanoparticles

Lu2SiO5:Ce powders were produced using solvent-free mechanochemistry. The Burgio-Rojac model for the planetary ball mill was used to conduct a parametric study of this synthesis, investigating the effect of varying the powder mass, the vial and ball density, the number of balls, the diameter of the balls, and the rotation rate of the mill on reaction time. The influence of additives was researched with Zn possibly leading to increased reduction of Ce4+ to Ce3+ and with various solvents hindering or preventing Lu2SiO5:Ce production. The solution and gel combustion syntheses of Lu2SiO5:Ce powders were executed using the fuels urea and hexamethylenetetramine both individually and as a mixture. The mixed-fuel solution combustion method successfully produced LSO:Ce powder with excellent replicability. This method produced LSO:Ce powders with a combination of the P 1 21/c 1and C 1 2/c 1 space groups, which were compared to mechanochemically-produce LSO:Ce powders with C 1 2/c 1 symmetry. Lu2SiO5:Ce powders produced by each method were sintered using either a microwave or a furnace. While furnace sintering increased intensity in their photoluminescence excitation and emission spectra, the intensity was decreased with microwave sintering. By furnace sintering the previously microwaved-sintered powder in air, it was determined that oxygen vacancies created during microwave sintering caused the loss of photoluminescence intensities. Preliminary studies were conducted to synthesize optically-active α[alpha]-quartz nanoparticles using optically-active β[beta]-GeO2 nanoparticles as a template. Templating optical activity in β[beta]-GeO2 nanoparticles using L-lysine and (R)-(+)-1,2-diaminopropane as templating agents was attempted. No optical activity was observed in polarimetry and circular dichroism measurements, which was most likely due to insufficient capping agent adsorption. Rac-β[beta]-GeO2 nanoparticles were used to attempt to template α[alpha]-quartz at room temperature as well as when heated in NaOH, NH4OH, Ba(OH)2, and CsOH solutions. α[alpha]-Quartz did not form in any powders although the silica may have dissolved during the heating

TheROOTS : Bridging the Gap Between Africa, Minstrelsy and Hip Hop

TheROOTS: Bridging the Gap between Afi ica, Minstrelsy and Hip Hop IS a thesis project written to look at the effects minstrelsy had on the early development of black dance in the United States, to pay tribute to Professor Sterling Stuckey\u27s research on slave culture, and the African-based tradition of the Ring Shout, which is performed in the Southern United States, as well as examine the contributions that African American, Jamaican, Afro-Brazilian and Puerto Rican culture, dance and music had on the early development of hip hop. The root of Hip Hop shows how artistic movements can be a vehicle for social change, cultural identity and passive/aggressive resistance against oppression

Core Formation in Partially Ionized Magnetic Molecular Clouds

Linear analysis of the formation of protostellar cores in planar magnetic interstellar clouds shows that molecular clouds exhibit a preferred length scale for collapse that depends on the mass-to-flux ratio and neutral-ion collision time within the cloud. This linear analysis can be used to investigate the formation of star forming clusters and the distribution of mass within star forming regions. By combining the results of the linear analysis with a realistic ionization profile for the cloud, we find that a molecular cloud may evolve through two fragmentation events in the evolution toward the formation of stars. Our model suggests that the initial fragmentation into clumps occurs for a transcritical cloud on parsec scales while the second fragmentation can occur for transcritical and supercritical cores on subparsec scales. Comparison of our results with several star forming regions (Perseus, Taurus, Pipe Nebula) shows support for a two-stage fragmentation model. Simulations of the thin-disk magnetohydrodynamic equations show that the two-stage fragmentation model is valid for a small region of parameter space assuming some form of recurrent density fluctuations within the region. In addition, applying Monte Carlo methods to these fragmentation length scales and distributions of other environmental variables (e.g., column density and mass-to-flux ratio) allow us to produce synthetic core mass functions (CMFs) for various environmental conditions. Our analysis shows that the shape of the CMF is directly dependent on the physical conditions of the cloud. Specifically, magnetic fields act to broaden the mass function and develop a high-mass tail while ambipolar diffusion will truncate this high-mass tail. We also analyze the effect of small number statistics on the shape and high-mass slope of the synthetic CMFs. We find that observed core mass functions are severely statistically limited, which has a profound effect on the derived slope for the high-mass tail

Posttraumatic Stress Disorder Among Rural Emergency Medical Services Personnel

Diagnostic criteria for posttraumatic stress disorder (PTSD) have undergone multiple revisions over the past few decades which have substantially refined our understanding of PTSD. Upon the publication of DSM-5, occupational exposure is now officially recognized as satisfying criterion A (exposure to a traumatic event) for the diagnosis of PTSD. First responder populations - particularly EMS personnel - have been historically understudied and warrant additional attention. The present study examines PTSD symptomology in a rural EMS population, as well as considering barriers to treatment. A total of 437 participants from West Virginia and western Pennsylvania completed a survey that included demographic information, exposure to traumatic events, PTSD symptoms, and perceived barriers to mental health care. Of those participants, 35% met criteria for provisional PTSD diagnoses. The majority of those individuals (96%) endorsed at least one traumatic event occurring as a part of their job. Barriers to accessing care in rural communities were identified, with the majority of participants endorsing personal financial difficulties, stigma, and employment as the most significant barriers. More intervention efforts are needed for rural EMS providers that target symptom recognition and treatment. Ultimately, the stigma of help-seeking behaviors should be addressed by supervisors and directors