Physical Sciences and Mathematics Commons^™

Kinetics And Mechanism Of Chromium Hexacarbonyl Photochemistry Using Flash By Photolysis, Marina Zaydman

Honors Theses

Chromium hexacarbonyl, Cr(CO)6, has been shown to be a very effective photochemical catalyst for many reactions, such as the 1,4- hydrogenation and 1 ,4-hydrosilation of conjugated 1 ,3-dienes resulting in the formation of a cis alkene product in greater than 99% yield. Although much research has been done on the reactions which Cr(CO)6 catalyzes, not much data exists on the reactions of photochemically created fragments of Cr(CO)6 , such as Cr(CO)6. This study focuses on the reactivity of organotransition metal intermediates with the goal of contributing to the growing database of the reactions involving the photochemistry of Cr(CO)6. Particular emphasis …

Sharp Frontal Interfaces In The Near-Surface Layer Of The Ocean In The Western Equatorial Pacific Warm Pool, Alexander Soloviev, Roger Lukas

Marine & Environmental Sciences Faculty Articles

During the TOGA COARE rich horizontal temperature and salinity variability of the near-surface layer of the ocean in the western Pacific warm pool was observed. High-resolution measurements were made by probes mounted on the bow of the vessel in an undisturbed region at ~1.7-m depth during four COARE cruises of the R/V Moana Wave. The authors observed several tens of cases of periodic sharp frontal interfaces of width 1– 100 m and separation 0.2–60 km. The sharp frontal interfaces were often found in frontal regions and on the periphery of freshwater puddles. Maneuvers of the ship were conducted to determine …

Physical Conditions Of The Coronal Line Region In Seyfert Galaxies, Jason W. Ferguson, Kirk Korista, Gary J. Ferland

Physics and Astronomy Faculty Publications

The launch of the Infrared Space Observatory and new atomic data have opened a window for the study of high-ionization gas in active galactic nuclei (AGNs). We present the results of a large number of photoionization simulations of the "coronal line" region in AGNs, employing new atomic data from the Opacity and Iron Projects. Our grid of line emission spans 8 orders of magnitude in gas density and 14 orders of magnitude in ionizing flux in an effort to identify the optimal conditions in which these lines form. We show that coronal lines form at distances from just outside the …

A Computational Study Of The Inclusion Processes Of Cyclodextrins And Cyclodextrin Polymers, James A. Best

Honors Theses

Cyclodextrins (CDs) are molecules that are composed of glucopyranose rings. Cyclodextrins can be formed from either 6, 7, or 8 glucopyranose units yielding, α-, β-, or y-Cyclodextrins respectively. Cyclodextrin polymers (COPs) can occur when glyceryl linkers are added to the previously mentioned cyclodextrins. CDs and COPs are hydrophilic, yet contain a hydrophobic cavity. This cavity allows for the binding of numerous guest molecules. Some practical purposes resulting from the host-guest interactions can be seen in cosmetology, food science, and pharmacy. Using the MacroModel Interactive Molecular Modeling System Version 5.0 we studied the binding of guest molecules to α-, β-, and …

The Crystallation Of Estrogen-Binding Protein From Candida Albicans, Chia-En Chen

Honors Theses

In the past decade scientists have discovered that the pathogenic fungus Candida albicans contains a highly specific estrogen-binding protein (EBP). Since it is known that the use of estrogen-containing compounds causes one to be more prone to infection by this organism, it is hypothesized that this estrogen system may have a role in infection. Understanding the structure and function of EBP would be helpful in developing treatments for infection by C. albicans. One way to approach the structure and function question of any protein is to crystallize the protein and solve its structure using X-ray diffraction. In the past few …

A Binding Investigation Of Fluorescence\Probes And Cyclodextrin Derivatives, Sara L. Mcintosh

Honors Theses

Cyclodextrins (CDs) are cyclical carbohydrates composed of repeating glucopyranose units. The three most common CDs, α-, β-, or y-, contain 6, 7 and 8 glucopyranose units, respectively, and have hydrophilic exteriors, which makes them water soluble. CD polymers (CDPs) have been synthesized, containing glyceryl link, between CD units. These polymers are more water soluble than their monomer counterparts. CDs and CDPs, because of their hydrophobic interior cavities, form inclusion complexes with various molecules, including aromatics. This latter property is one we have investigated using fluorophores, including naphthalenes and pyrene. We have shown, through absorption spectral and fluorescence lifetime data, that …

The Prairie Naturalist Volume 29, No.2. June 1997

The Prairie Naturalist

CHRISTMAS BIRD COUNTS FOR NORTH DAKOTA - 1996 ▪ . R. N. Randall

BREEDING BIRD RICHNESS IN THE PRAIRIE POTHOLE REGION OF MINNESOTA ▪ . S. L. Niesar and D. E. Hubbard

UNUSUAL MIGRATION BY A WHITE-TAILED DEER FAWN IN SOUTH DAKOTA ▪ C. S. DePerno, S. L. Griffin, J. A. Jenks, and L. A. Rice

COYOTE FOOD HABITS AT DESOTO NATIONAL WILDLIFE REFUGE, NEBRASKA ▪ J. J. Huebschman, S. E. Hygnstrom, and J. A. Gubanyi

WHITE BASS GROWTH IN SOUTH DAKOTA WATERS ▪ D. W. Willis, H. D. Beck, C. A. Soupir, B. A. Johnson, G. D. Simpson, and …

An Improved Multi-Layer Fabrication Process For Yba2Cu3O7-X-Based Circuits, H.Q. Li, R.H. Ono, L.R. Vale, D.A. Rudman, Sy_Hwang Liou, W.H. Mallison

Sy-Hwang Liou Publications

Improved via connections in structures of YBa₂Cu₃O_7-x/SrTiO₃/ YBa₂Cu₃O_7-x (YBCO/STO/YBCO) multilayers have been made using a combined HF wet-etching and ion-milling process. The critical current density J_c of the via is as high as 2×10⁶ A/cm² at 76 K, and is dominated by edge contacts in the ab-plane, YBCO and Sr₂AlNbO₆ (SAN) multilayer test circuits were also made with this process. The 4° crossovers in a SAN test chip had a critical temperature T_c of 88 K and J_{c …}

Localization And Transport Effects In The Disordered Materials, Vladislav Malyshkin

Dissertations

No abstract provided.

Debye-Series Analysis Of The First-Order Rainbow Produced In Scattering Of A Diagonally Incident Plane Wave By A Circular Cylinder, James A. Lock, Charles L. Adler

Physics Faculty Publications

We derive the Debye-series expansion of the partial-wave scattering and interior amplitudes for the interaction of a diagonally incident beam of arbitrary profile with an infinitely long homogeneous dielectric circular cylinder. We then discuss the physical interpretation of the various terms of the series. We also consider the one-internal-reflection Debye-series terms for diagonal plane-wave incidence and examine the first-order rainbow extinction transition as a function of the tilt angle of the incident plane wave. We experimentally observe the first-order rainbow extinction transition and compare our observations with the Debye-series predictions. (C) 1997 Optical Society of America.

Anharmonic Potentials In Supercooled Liquids: The Soft-Potential Model, Ulrich Zürcher, T. Keyes

Physics Faculty Publications

Instantaneous normal modes (INM) are the harmonic approximation to liquid dynamics. This is an extension of the phonon description of lattice dynamics, in which case Bloch's theorem shows that all modes are extended. Long-range order is destroyed in liquids and glasses, and the INM spectrum has contributions from both extended and localized modes. We use the soft-potential mode to describe localized modes. This model is a high-temperature extension of the standard two-level-system model for glasses. The equilibrium position of any atom in the liquid has only temporary character, and relaxation processes in the liquid are associated with particles hopping over …

The Complexity Of Clerkship Scheduling, Jonathan Feldman

Dartmouth College Undergraduate Theses

Medical students must complete a clerkship program in their fourth year. Individual students have preferences for the clerkships to which they are assigned. However, individual hospitals also have capacities on how many students may be assigned to each clerkship. The problem of scheduling medical students to clerkships is formalized. The problem is then placed in a theoretical framework, and the most general case of Clerkship Scheduling is proven NP-hard. A detailed approximation algorithm is given, and an implementation of this algorithm is discussed and tested.

Autonomous Construction Of Multi Layer Perceptron Neural Networks, Thomas F. Rathbun

Theses and Dissertations

The construction of Multi Layer Perceptron (MLP) neural networks for classification is explored. A novel algorithm is developed, the MLP Iterative Construction Algorithm (MICA), that designs the network architecture as it trains the weights of the hidden layer nodes. The architecture can be optimized on training set classification accuracy, whereby it always achieves 100% classification accuracies, or it can be optimized for generalization. The test results for MICA compare favorably with those of backpropagation on some data sets and far surpasses backpropagation on others while requiring less FLOPS to train. Feature selection is enhanced by MICA because it affords the …

Kinetics And Spectroscopy Of Brno, Patrick E. Godfrey

Theses and Dissertations

The infrared spectra and photochemistry of nitrosyl bromide, BrNO, are important to characterizing the performance of a recently demonstrated Br(²P_1/2)-NO(v=2 → v=1) transfer laser pumped by photolysis of iodine molecules. This wavelength agile, mid-infrared laser may be a desirable source for remote sensing and infrared countermeasures missions. Nitrosyl bromide also plays a role in the destruction of stratospheric ozone. The kinetics of BrNO formation and destruction were examined using time-resolved photolysis techniques. The equilibrium constant for the dark reaction Br₂ + 2NO (reversible reaction) 2BrNO was determined as K_eq 168 ± 23 /atm and …

Optimization Considerations For Adaptive Optics Digital Imagery Systems, Robert T. Brigantic

Theses and Dissertations

This dissertation had three objectives. The first objective was to develop image quality metrics that characterize Adaptive Optics System (AOS) performance. The second objective was to delineate control settings that maximize AOS performance. The third objective was to identify and characterize trade-offs between fully and partially compensated adaptive. For the first objective, three candidate image quality metrics were considered: the Strehl ratio, a novel metric that modifies the Strehl ratio by integrating the modulus of the average system optical transfer function to a 'noise-effective-cutoff' frequency at which some specified image spectrum signal-to-noise-ratio level is attained, and the noise-effective-cutoff frequency. It …

Numerical Modeling Of Self-Propagating Polymerization Fronts: The Role Of Kinetics On Front Stability, Stanislav E. Solovyov, Victor M. Ilyashenko, John A. Pojman

Faculty Publications

Frontal propagation of a highly exothermic polymerization reaction in a liquid is studied with the goal of developing a mathematical model of the process. As a model case we consider monomers such as methacrylic acid and n-butyl acrylate with peroxide initiators, although the model is not limited to these reactants and can be applied to any system with the similar basic polymerization mechanism. A three-step reaction mechanism, including initiation, propagation and termination steps, as well as a more simple one-step mechanism, were considered. For the one-step mechanism the loss of stability of propagating front was observed as a sequence …

Interpretation Of Ultraviolet Absorption Lines In Sn 1006, A. J. S. Hamilton, R. A. Fesen, C.-C. Wu, D. M. Crenshaw

Dartmouth Scholarship

We present a theoretical interpretation of the broad silicon and iron ultraviolet absorption features observed with the Hubble Space Telescope (HST) in the spectrum of the Schweizer-Middleditch star behind the remnant of SN 1006. These features are caused by supernova ejecta in SN 1006.

We propose that the redshifted Si II 1260 Å feature consists of both unshocked and shocked Si II. The sharp red edge of the line at 7070 km s^-1 indicates the position of the reverse shock, while its Gaussian blue edge reveals shocked Si with a mean velocity of 5050 km s^{-1 …}

Use Of Fluorescence Microscopy In An Assay Of Sperm Density For The Gorgonian Coral, Plexaura Kuna, Timothy D. Swain, K. Kim, H. R. Lasker

Marine & Environmental Sciences Faculty Proceedings, Presentations, Speeches, Lectures

The density of sperm in the water column during the broadcast spawning events of marine invertebrates is often undetermined or reported in terms of fertilization potential. The density of sperm during such events can be determined by directly counting numbers of spermatozoa using a modification of the acridine orange direct count (AODC) technique for enumerating bacteria. A number of variables in the handling and processing of samples may bias estimates. Sample collection in glass and rapid fixation and filtration are necessary for reproducible estimates. Once filtered, samples are stable for many months, and counts on filters that were poorly stained …

A Descriptive Survey Of Freshwater Unionidae Bivalves In Five Creeks Located In West Central Georgia, Rufus Carson Stringfellow

Theses and Dissertations

A descriptive survey of the West Georgia, Chattahoochee River drainage unionid bivalve fauna inhabiting Mountain Oak, Mulberry, Standing Boy, and Upatoi Creeks has been completed. The survey is intended to determine whether Unionidae populations remain extant in this portion of the Chattahoochee River drainage, and to estimate the abundance and distribution of species encountered. Accessibility sampling was employed; sites selected to be surveyed were usually located at a road bridge or some landmark easily identifiable for geographical positioning. Collecting methods included the use of a small rake in sandy or silty substrate, visual detection of siphons or trails in the …

Native Vegetation Handbook For The Shire Of Bridgetown-Greenbushes, Shaun B. Grein

Native vegetation handbook series

This booklet provides rural land managers with information relating to the natural resources of the Shire of Bridgetown-Greenbushes including the existing vegetation, drainage systems and soils. Some of the problems relating to the management of natural resources in the Shire of Bridgetown-Greenbushes and possible solutions to these problems are also discussed. By providing this information, it is hoped this booklet will contribute to the long term viability of the rural landscape and the conservation of native vegetation within the Shire.

Symmetry Breaking In Crossed Magnetic And Electric Fields, C. Neumann, R. Ubert, S. Freund, Et Al., John B. Delos

Arts & Sciences Articles

We present the first observations of cylindrical symmetry breaking in highly excited diamagnetic hydrogen with a small crossed electric field, and we give a semiclassical interpretation of this effect. As the small perpendicular electric field is added, the recurrence strengths of closed orbits decrease smoothly to a minimum, and revive again. This phenomenon, caused by interference among the electron waves that return to the nucleus, can be computed from the azimuthal dependence of the classical closed orbits.

Breakdown Of The Independent Particle Approximation In High-Energy Photoionization, E. W. B. Dias, H. S. Chakraborty, P. C. Deshmukh, S. T. Manson, Oliver Hemmers, P. Glans, D. Hansen, H. Wang, S. B. Whitfield, Dennis W. Lindle, R. Wehlitz, Jon C. Levin, I. A. Sellin

Environmental Studies Faculty Publications

The independent particle approximation is shown to break down for the photoionization of both inner and outer nℓ (ℓ>0) electrons of all atoms, at high enough energy, owing to interchannel interactions with the nearby ns photoionization channels. The effect is illustrated for Ne 2p in the 1 keV photon energy range through a comparison of theory and experiment. The implications for x-ray photoelectron spectroscopy of molecules and condensed matter are discussed.

Estimation Of Groundwater Velocities From Yucca Flat To The Amargosa Desert Using Geochemistry And Environmental Isotopes, Ronald L. Hershey, Steve Y. Acheampong

Publications (WR)

Geochemical modeling techniques were applied to groundwater flowpaths from Yucca Flat on the Nevada Test Site (NTS) to the Amargosa Desert, south of the NTS to estimate groundwater flow velocities for independent comparison to velocities calculated by other methods. The groundwater flowpaths examined considered flow in the carbonate aquifer beneath Yucca and Frenchman flats mixing with flow from carbonate aquifers east and southeast of the NTS and discharging at wells south of the NTS border. The approach used the computer codes WATEQ4F and NETPATH to calculate chemical speciation, determine the saturation state of mineral phases, and simulate mixing and the …

Artificial Recharge In The Las Vegas Valley: An Operational History, Michael Johnson, Erin Cole, Kay Brothers, Las Vegas Valley Water District

Publications (WR)

Artificially recharging the Las Vegas Valley (Valley) ground-water system with treated Colorado River water is one water resource management option employed by the Las Vegas Valley Water District (District) to help meet future long-term and short-term peak water demands. The District began operation of an artificial ground-water recharge program in 1988 in order to bank water for future use and to slow declining water levels. Artificial recharge occurs in the winter months, typically from October to May, when there is excess capacity in the Southern Nevada Water System (SNWS), currently a 400 Million Gallon per Day (MGD) treatment and transmission …

Numerical Simulations Of Gravity Waves Imaged Over Arecibo During The 10-Day January 1993 Campaign, M. P. Hickey, R. L. Walterscheid, Michael J. Taylor, W. Ward, G. Schubert, Q. Zhou, F. Garcia, M. C. Kelley, G. G. Shepherd

All Physics Faculty Publications

Recently, measurements were made of mesospheric gravity waves in the OI (5577 Å) nightglow observed from Arecibo, Puerto Rico, during January 1993 as part of a special 10-day campaign. Clear, monochromatic gravity waves were observed on several nights. By using a full-wave model that realistically includes the major physical processes in this region, we have simulated the propagation of two waves through the mesopause region and calculated the O(1 S) nightglow response to the waves. Mean winds derived from both UARS wind imaging interferometer (WINDII) and Arecibo incoherent scatter radar observations were employed in the computations as were the climatological …

Wright State University College Of Engineering And Computer Science Bits And Pcs Newsletter, Volume 13, Number 6, June 1997, College Of Engineering And Computer Science, Wright State University

BITs and PCs Newsletter

Wright State University College of Engineering and Computer Science

Assessment Of The Environmental Impact Of Re-Injecting Oil-Field Water Into The Miocene Clastic Sediments On The Shallow Aquifer In The Bu Hasa Oil Field, United Arab Emirates, Khalid Ali Al Amari

Theses

The Bu Hasa oil field is located about 200 km southwest of Abu Dhabi City in the U.A.E. Oil production from the field started in 1965 and a water injection program was initiated in 1970. This research is focused on the assessment of the environmental hazards to the Quaternary Liwa aquifer from either the re-injection of oil-field water into the Miocene Clastic aquifer or surface dumping into unlined pits.

Well logs, core samples, structure and isopach contour maps, stratigraphic cross sections, and water chemistry analyses were utilized in this study. Moreover, a detailed hydrogeological aquifer assessment was conducted and a …

Scientific Facts Vs. Political Values, Thomas G. Field Jr.

RISK: Health, Safety & Environment (1990-2002)

Professor Field takes exception to a recent Science editorial.

Continuous Monitoring Of Surface Deformation At Long Valley Caldera, California, With Gps, Timothy H. Dixon, Ailin Mao, Marcus Bursik, Michael Heflin, John Langbein, Ross Stein, Frank Webb

School of Geosciences Faculty and Staff Publications

Continuous Global Positioning System (GPS) measurements at Long Valley Caldera, an active volcanic region in east central California, have been made on the south side of the resurgent dome since early 1993. A site on the north side of the dome was added in late 1994. Special adaptations for autonomous operation in remote regions and enhanced vertical precision were made. The data record ongoing volcanic deformation consistent with uplift and expansion of the surface above a shallow magma chamber. Measurement precisions (1 standard error) for “absolute” position coordinates, i.e., relative to a global reference frame, are 3–4 mm (north), 5–6 …

Physiologically-Based Vision Modeling Applications And Gradient Descent-Based Parameter Adaptation Of Pulse Coupled Neural Networks, Randy P. Broussard

Theses and Dissertations

In this research, pulse coupled neural networks (PCNNs) are analyzed and evaluated for use in primate vision modeling. An adaptive PCNN is developed that automatically sets near-optimal parameter values to achieve a desired output. For vision modeling, a physiologically motivated vision model is developed from current theoretical and experimental biological data. The biological vision processing principles used in this model, such as spatial frequency filtering, competitive feature selection, multiple processing paths, and state dependent modulation are analyzed and implemented to create a PCNN based feature extraction network. This network extracts luminance, orientation, pitch, wavelength, and motion, and can be cascaded …