Physical Sciences and Mathematics Commons^™

Investigation Of The Relationship Between Particulate Bound Mercury And Properties Of Fly Ash In A Full-Scale 100 Mwe Pulverized Coal Combustion Boiler, Sen Li

Masters Theses & Specialist Projects

There is an increasing concern over mercury emissions from coal-fired boilers. Coal-fired power generation accounts for approximately 33% of total mercury emission in the United States. Once it is emitted into the atmosphere and deposited on land or water, mercury can transform into methylmercury, an organic form. Mercury can then enter the food chain, which poses a potential threat to human health and the environment. To study the relationship between particulate bound mercury and fly ash properties, fly ash samples were collected from the mechanical hopper (MHP) and the electrostatic precipitator (ESP) of a 100 MWe pulverized coal-fired boiler and …

Direct Multielemental Analysis Of Solid Samples Using Laser Ablation Inductively Coupled Plasma Mass Spectometry And Pulsed Radio Frequency Glow Discharge Mass Spectrometry, Joseph Miller

Masters Theses & Specialist Projects

Direct solid sampling is an area of analytical research that has generated a large amount of interest in recent years. Two analysis systems offering fast and nondestructive methods of determining the elemental composition of substances, without requiring complicated sample preparation procedures, are laser ablation inductively coupled plasma mass spectroscopy (LA-ICPMS) and radio frequency glow discharge mass spectroscopy (rf-GDMS). A Cetac LSX-200 laser system coupled to a LECO Renaissance ICPMS was utilized to analyze coal and ash samples prepared by incorporation into a lithium borate matrix to form a disk. In addition, a VG 9000 Glow Discharge Mass Spectrometer (GDMS) with …

Solubility And Freezing Effects Of Fe2+ And Mg2+ In H2so4 Solutions Representative Of Upper Tropospheric And Lower Stratospheric Sulfate Particles, Matthew E. Wise, Sarah D. Brooks, Rebecca M. Garland, Daniel J. Cziczo, Scot T. Martin, Margaret A. Tolbert

CUP Faculty Research

Chemical elements characteristic of earth minerals and meteorites are present within background tropospheric and stratospheric sulfate aerosol particles. However, it is unknown if these elements are present predominantly as solids, including possible sulfates, carbonates, and oxides, or rather as soluble aqueous metal ions or complexes. Further, it is unclear how these impurities could affect particle freezing. To address these questions, we have determined the total equilibrium metal solubility ([Fe²⁺]_T and [Mg²⁺]_T) in 20–90 wt % sulfuric acid solutions over the temperature range 200–300 K. We have measured solubilities using samples of MgSO_{4 …}

A Multicentered Approach To Integrated Qm/Qm Calculations. Applications To Multiply Hydrogen Bonded Systems, Brian W. Hopkins, Gregory S. Tschumper

Chemistry Faculty Research & Creative Works

A multicentered integrated QM/QM technique has been developed. By separating high-level calculations in distinct regions of molecules, the multicentered approach supplants a single large high-level calculation with several smaller calculations. Due to the step polynomial scaling of traditional ab initio quantum chemical methods, this separation significantly enhances the computational efficiency of QM/QM methods. The straightforward implementation of this multicentered approach is illustrated with several large poly-alcohols that form hydrogen bonds with water. The largest alcohol-water complex contains 81 atoms. For properly selected model systems, this multicentered approach introduces essentially no error in the dissociation energies of these complexes relative to …

45th Rocky Mountain Conference On Analytical Chemistry

Rocky Mountain Conference on Magnetic Resonance

Final program, abstracts, and information about the 45th annual meeting of the Rocky Mountain Conference on Analytical Chemistry, co-endorsed by the Colorado Section of the American Chemical Society and the Rocky Mountain Section of the Society for Applied Spectroscopy. Held in Denver, Colorado, July 27-31, 2003.

Amino Acids Glu323, Tyr324, Glu330, And Val331 Of Factor Va Heavy Chain Are Essential For Expression Of Cofactor Activity, Lisam S. Singh, Michael A. Bukys, Daniel O. Beck, Michael Kalafatis

Chemistry Faculty Publications

We have recently demonstrated that amino acid region 323-331 of factor Va heavy chain (9 amino acids, AP4') contains a binding site for factor Xa (Kalafatis, M., and Beck, D. O. (2002) Biochemistry 41, 12715-12728). To ascertain which amino acids within this region are important for the effector and receptor properties of the cofactor with respect to factor Xa, we have synthesized three overlapping peptides (5 amino acids each) spanning the amino acid region 323-331 and tested them for their effect on prothrombinase complex assembly and function. Peptide containing amino acids 323EYFIA327 alone was found to increase the catalytic efficiency …

Cross-Section Measurements For The Near Ultra-Violet Absorption Spectra Of Glyoxal At The 280 Nanometer Wavelength, Abigail Diaz

FIU Electronic Theses and Dissertations

Glyoxal and other dicarbonyl compounds have been detected in tropospheric air in rural areas and polluted urban areas. Accurate absorption cross-sections for the near UV spectrum of glyoxal are important since the value of this chemical characteristic is necessary for calculating effective quantum yields and ultimately the rates and products of photolysis. In this study, comprehensive measurements were made for the 2 80 nm gas-phase absorption spectrum of glyoxal. In addition, molecular orbital calculations were carried out and the results used as a guide to identify the vibration responsible for the weak structure features of the continuous area of the …

Trace Gas Measurements In Nascent, Aged, And Cloud-Processed Smoke From African Savanna Fires By Airborne Fourier Transform Infrared Spectroscopy (Aftir), Robert J. Yokelson, Issac T. Bertschi, Ted J. Christian, Peter V. Hobbs, Darold E. Ward, Wei Min Hao

Chemistry and Biochemistry Faculty Publications

[1] We measured stable and reactive trace gases with an airborne Fourier transform infrared spectrometer (AFTIR) on the University of Washington Convair-580 research aircraft in August/September 2000 during the SAFARI 2000 dry season campaign in Southern Africa. The measurements included vertical profiles of CO₂, CO, H₂O, and CH₄ up to 5.5 km on six occasions above instrumented ground sites and below the TERRA satellite and ER-2 high-flying research aircraft. We also measured the trace gas emissions from 10 African savanna fires. Five of these fires featured extensive ground-based fuel characterization, and two were in the …

Emissions Of Trace Gases And Particles From Savanna Fires In Southern Africa, Parikhit Sinha, Peter V. Hobbs, Robert J. Yokelson, Isaac T. Bertschi, Donald R. Blake, Isobel J. Simpson, Song Gao, Thomas W. Kirchstetter, Tihomir Novakov

Chemistry and Physics Faculty Articles

Airborne measurements made on initial smoke from 10 savanna fires in southern Africa provide quantitative data on emissions of 50 gaseous and particulate species, including carbon dioxide, carbon monoxide, sulfur dioxide, nitrogen oxides, methane, ammonia, dimethyl sulfide, nonmethane organic compounds, halocarbons, gaseous organic acids, aerosol ionic components, carbonaceous aerosols, and condensation nuclei (CN). Measurements of several of the gaseous species by gas chromatography and Fourier transform infrared spectroscopy are compared. Emission ratios and emission factors are given for eight species that have not been reported previously for biomass burning of savanna in southern Africa (namely, dimethyl sulfide, methyl nitrate, five …

Evolution Of Gases And Particles From A Savanna Fire In South Africa, Peter V. Hobbs, Parikhit Sinha, Robert J. Yokelson, Ted J. Christian, Donald R. Blake, Song Gao, Thomas W. Kirchstetter, Tihomir Novakov, Peter Pilewskie

Chemistry and Physics Faculty Articles

Airborne measurements of particles and gases from a 1000-ha savanna fire in South Africa are presented. These measurements represent the most extensive data set reported on the aging of biomass smoke. The measurements include total concentrations of particles (CN), particle sizes, particulate organic carbon and black carbon, light-scattering coefficients, downwelling UV fluxes, and mixing ratios for 42 trace gases and 7 particulate species. The ratios of excess nitrate, ozone, and gaseous acetic acid to excess CO increased significantly as the smoke aged over ∼40–45 min, indicating that these species were formed by photochemistry in the plume. For 17 other species, …

Global Geometry Optimization Of Silicon Clusters Described By Three Empirical Potentials, S. Yoo, Xiao Cheng Zeng

Xiao Cheng Zeng Publications

The “basic-hopping” global optimization technique developed by Wales and Doye is employed to study the global minima of silicon clusters Si_n (3<nnnn=17, as opposed to n=19. For larger SW clusters (20<n n =20. In particular, the overall structural features of SW Si₂₁, Si₂₃, Si₂₅, and Si₂₈ are nearly identical to the MSW counterparts. With the SW Si₂₁ as the starting structure, a geometric optimization at the B3LYP/6-31G(d) level of density-functional theory yields an isomer similar to the ground-stateisomer of Si₂₁ reported by Pederson et …

Reductivedesorption Of 11-Mercaptoundecanoic Acid Monolayers Modified By Covalent Attachment Of 1,3- And 1,4-Phenylenediamine, Mark Anderson, Richard Baltzersen

Mark R. Anderson

1,3- and 1,4-phenylenediamine were covalently attached to a self-assembled monolayer of 11-mercaptoundecanoic acid by formation of an amide bond. Bonding of the phenylenediamine isomers was confirmed by the presence of infrared features attributable to ring vibrational modes, the amide I vibration, and the amide II vibration in the reflection–absorption infrared spectrum of the modified interface. Reductivedesorption peak potentials were shifted by 120 mV for the monolayer modified by 1,4-phenylenediamine and by 90 mV for the monolayer modified by 1,3-phenylenediamine relative to the desorption potential of the unmodified 11-mercaptoundecanoic acid monolayer. These potential shifts represent 23 and 17 kJ/mol stabilization of …

High-Temperature Fiber Matrices: Electrospinning And Rare-Earth Modification, W. Kataphinan, R. Teye-Mensah, Edward A. Evans, R. D. Ramsier, D. H. Reneker, D. J. Smith

Chemical, Biomolecular, and Corrosion Engineering Faculty Research

We demonstrate the production of nonwoven mats of high-temperature organic and inorganic fibers by electrospinning. Specifically, glass/ceramic (tetraethylorthosilicate-SiO) and fire-blanket (polydiphenoxyphosphazene-PDPP) precursors are electrospun, and the resulting fibers are characterized by scanning electron microscopy, thermogravimetric analysis, and infrared (IR) spectroscopy. We find that the SiO fibers are smaller in diameter and more uniform than the PDPP fibers, and stable to higher temperatures. We also coat these fiber systems with several rare-earth nitrates, and find that these coatings can be used to selectively modify the near-IR spectra of the fibers. This work extends the use of electrospinning into two new classes …

Nanoscale Oxidation Of Zirconium Surfaces: Kinetics And Mechanisms, N. Farkas, G. Zhang, Edward A. Evans, R. D. Ramsier, J. A. Dagata

Chemical, Biomolecular, and Corrosion Engineering Faculty Research

We show that atomic force microscope-induced oxide features can be formed reproducibly on both Zr and ZrN surfaces, and that the growth rate decreases rapidly with increasing time. There is an increase in oxide-feature height with humidity for both systems, and an approximately linear dependence of the height of the structures on the applied voltage for all films for short exposure times. As the anodization time increases, only the thinnest (6 nm) films show a large enhancement in oxide-feature height, demonstrating the role of the film/substrate interface. Under the same conditions, the height of features grown on ZrN films is …

Multidentate Sulfur-Containing Ligands, David A. Atwood, Brock S. Howerton, Matthew Matlock

Chemistry Faculty Patents

Novel sulfur-containing ligands for binding of heavy metals are disclosed.

To read the remainder of this abstract, please download this patent.

Bulk And Interfacial Properties Of A Dipolar-Quadrupolar Fluid In A Uniform Electric Field: A Density-Functional Approach, V.B. Warshavsky, Xiao Cheng Zeng

Xiao Cheng Zeng Publications

We have studied the bulk and interfacial properties of a dipolar-quadrupolar fluid based on an extended modified mean-field density-functional theory. Effects of a uniform electric field on the bulk and interfacial properties are also studied. Results of the coexisting vapor-liquid densities, interfacial profiles of the density and orientation order parameters, the surface tension, and their dependence on the temperature, magnitude of molecule dipole and quadrupole moment, and the applied field are obtained. In general, we find that the applied field increases the critical temperature, broadens the vapor-liquid coexistence curves, and reduces the surface tension. We also find that if the …

Markov Chains And Dynamic Geometry Of Polygons, Jiu Ding, L. Richard Hitt, Xin-Min Zhang

Faculty Publications

In this paper we construct sequences of polygons from a given n-sided cyclic polygon by iterated procedures and study the limiting behaviors of these sequences in terms of non-negative matrices and Markov chains. (C) 2003 Elsevier Science Inc. All rights reserved.

Untangling The Web: The National Digital Libraries Initiative, Dean Johnston

Chemistry Faculty Scholarship

A report on the National Digital Libraries Initiative is presented. To facilitate access to the vast resources of the Internet, the National Science Foundation has created the Digital Libraries Initiative. Several sites have come online recently that index and catalog materials in a way similar to a library, providing additional information about each site. The official National Science Digital Library Web site has the potential to become a one-stop site for a wide range of educational science material.

E1-E2 Interference In The Vuv Photoionization Of He, E. P. Kanter, B. Krassig, S. H. Southworth, Renaud Guillemin, Oliver Hemmers, Dennis W. Lindle, R. Wehlitz, M. Ya Amusia, L. V. Chernysheva, N. L. S. Martin

Environmental Studies Faculty Publications

We have measured the forward-backward asymmetry of photoelectron angular distributions produced in the vacuum ultraviolet photoionization of helium. This asymmetry, a consequence of the breakdown of the dipole approximation, measures the real part of the ratio of the quadrupole and dipole matrix elements. In the autoionization region, the strong energy dependence of the asymmetry permits an experimental separation of the ratio of those magnitudes from their phase difference. We experimentally determined the Fano parameters of the 2p²¹D₂ quadrupole resonance, and report improved values of the width Γ and line profile parameter q from those previously available …

One-Step Processing Of Spinel Ferrites Via The High-Energy Ball Milling Of Binary Oxides, V. G. Harris, D. J. Fatemi, J. O. Cross, E. E. Carpenter, V. M. Browning, J. P. Kirkland, Amitabh Mohan, Gary J. Long

Chemistry Faculty Research & Creative Works

MnZn ferrites have been produced via the high-energy ball milling of binary oxide precursors. The milled ferrites have a nonequilibrium cation site distribution, with an unusually high population of Zn cations on the octahedral sites. The particle size distribution drops precipitously with milling time from 60±1 to ∼14±1 nm at 10 h, but increases to 18.5±1 nm after long durations (20–40 h) concurrent with the formation of nearly pure ferrite. A 1 h anneal at 673 K facilitates a redistribution of cations to their near equilibrium sites. This processing approach circumvents the need for deleterious high-temperature heat treatments that often …

Methyl And T-Butyl Group Reorientation In Planar Aromatic Solids: Low-Frequency Nuclear Magnetic Resonance Relaxometry And X-Ray Diffraction, Peter A. Beckmann, Carylon Buser, Kathleen Gullifer, Frank B. Mallory, Clelia W. Mallory, Gene M. Rossi, Arnold L. Rheingold

Chemistry Faculty Research and Scholarship

We have synthesized 3-t-butylchrysene and measured the Larmor frequency omega/2pi (= 8.50, 22.5, and 53.0 MHz) and temperature T (110-310 K) dependence of the proton spin-lattice relaxation rate R in the polycrystalline solid [low-frequency solid state nuclear magnetic resonance (NMR) relaxometry]. We have also determined the molecular and crystal structure in a single crystal of 3-t-butylchrysene using x-ray diffraction, which indicates the presence of a unique t-butyl group environment. The spin-1/2 protons relax as a result of the spin-spin dipolar interactions being modulated by the superimposed reorientation of the t-butyl groups and their constituent methyl groups. The reorientation is successfully …

Environment-Induced Degradation And Crack-Growth Studies Of Candidate Target Materials: Annual Progress Report (May 2002 – May 2003), Ajit K. Roy, Brendan O'Toole

Transmutation Sciences Materials (TRP)

As indicated in the original proposal, the primary objective of this task is to evaluate the effect of hydrogen on environment-assisted cracking of candidate target materials for applications in spallationneutron- target (SNT) systems such as accelerator production of tritium (APT) and accelerator transmutation of waste (ATW). The materials selected for evaluation and characterization are martensitic stainless steels including Alloy HT-9, Alloy EP 823 and Type 422 stainless steel. The susceptibility to stress corrosion cracking (SCC) and hydrogen embrittlement (HE) of these materials are being evaluated in aqueous environments of interest using tensile specimens under constant load and slow-strain-rate (SSR) conditions. …

Quelques Conseils À Nos Nouveau Diplomés, Fathi Habashi

Fathi Habashi

An advice, the old wise man Polonius offered to the young Hamlet was “Neither a borrower, nor a lender be”, may be no longer pertinent. Some more relevant advices are offered to new graduates of the twentieth century. Available in English, French, and Spanish

Thickness Dependence Of Magnetic Blocking In Granular Thin Films, Scott Whittenburg

Chemistry Faculty Publications

Interparticle interaction among single domain nanosize magnetic particles embedded in nonmagnetic matrix was studied. Attention was paid to concentrated Cu–Co granular thin films with a fixed magnetic volume fraction 20%. By analyzing theoretical models and comparing with experimental results, a dimensional constraint on the magnetic properties was found. As the film thickness reduces toward the thin limit the interparticle interaction plays important roles in modifying the magnetic behavior. The dipolar interaction energy was calculated among magnetic particles including far-neighbor interaction for films with different thickness values. When magnetization variation is included in the calculation, the resulting calculated interaction energy versus …

Thickness Dependence Of Magnetic Blocking In Granular Thin Films With Interacting Magnetic Particles, Jian Qing Wang, Zhi Dong Zhao, Scott L. Whittenburg

Chemistry and Biochemistry Faculty Publications

Interparticle interaction among single domain nanosize magnetic particles embedded in nonmagnetic matrix was studied. Attention was paid to concentrated Cu–Co granular thin films with a fixed magnetic volume fraction (20%). By analyzing theoretical models and comparing with experimental results, a dimensional constraint on the magnetic properties was found. As the film thickness reduces toward the thin limit the interparticle interaction plays important roles in modifying the magnetic behavior. The dipolar interaction energy was calculated among magnetic particles including far-neighbor interaction for films with different thickness values. When magnetization variation is included in the calculation, the resulting calculated interaction energy versus …

Sol-Gel-Platform Optical Sensors For Oxygen Gas : Sensor Development And Investigation Of Probe Partitioning In Sol-Gel Matrices, Desiree L. Plata

Honors Theses

I have developed gas sensors that respond rapidly and noticeably to changes in oxygen concentration by doping fluorescent complexes into gas-permeable sol-gel materials. Ruthenium (II) 4,7-diphenyl-1,10- phenanthroline, Ru(dpp)32+, responds to variations in ambient oxygen concentrations through marked changes in its fluorescence intensity. I investigated the response of Ru(dpp)32+ to oxygen in solution, in aerogels (sol gels dried under ambient conditions) and in aerogels (sol gels dried using supercritical conditions). Aerogels have particularly high porosity and low density, which allows for rapid diffusion of gases into the material. The aerogel sensor responds reversibly to changes in ambient oxygen concentration within 10 …

The Use Of Fluorescence To Investigate The Factors Leading To Complex Formation Between Naphthalenes And ├Ƒ-Cyclodextrins, Jamie M. Iannacone

Honors Theses

Fraiji et al. determined a binding constant (K) of 581 = 6 M-1 for the 1:1 complex between 2-acetylnaphthalene (2-AN) and β-cyclodextrin (β-CD) in H20 using fluorescence quenching experiments (Appl. Spectrosc. 1994, 48, 79). Molecular modeling experiments indicate the possibility of complex stabilization resulting from hydrogen bonds between the C=O group of 2-AN and the -OH groups on the rim of β-CD. To check this possibility, we measured the K of the 2-AN:trimethyl-β-CD (TM-β- CD) complex, where all rim -OH groups are converted to –OCH3. In this case, K decreases to 134 M-1. To show that this is due to …

Solution Structure Refinement Comparing Reference Model Noe Volumes, Maura Mahar

Honors Theses

NMR is a powerful experimental technique which can be used to determine protein structures. Central to this process is conversion of peak volumes in the NOE data sets into distance constraints and then structural refinement against those constraints. In general, each solution structural analysis is initiated de novo. We are interested in the structural analysis of a series of hybrids derived from two parental proteins (rubredoxins from mesophilic bacterium Clostridium pasteurianum (Cp) and the hyperthermophilic archaeon Pyrococcus furiosus (Pf)). Near 1 A resolution X-ray structures of Cp and Pf rubredoxins are available to provide a basis for quantitative comparison of …

Investigation Of Indicators In Aerogels And Xerogels, Rebecca L. Wolfe

Honors Theses

A sol-gel is a silicon-oxygen matrix that is suitable for the entrapment of chemical species, including biological species, indicators, dyes, and sensors. Aerogels are sol-gels prepared by supercritical extraction, whereas aerogels are allowed to dry under ambient conditions. The resulting materials differ considerably in their physical properties. We are investigating a series of luminescent species for use as probes of the microenvironment in different sol-gel materials. Sol gels containing each probe are prepared as both aerogels and aerogels; aerogels are formed using a novel contained mold process. Spectral properties, including absorption or excitation spectra, emission spectra, time-based fluorescence scans, and …

Perilipin A Is Essential For The Translocation Of Hormone-Sensitive Lipase During Lipolytic Activation. J Cell Biol, John Tansey

Chemistry Faculty Scholarship

A key step in lipolytic activation of adipocytes is the translocation of hormone-sensitive lipase (HSL) from the cytosol to the surface of the lipid storage droplet. Adipocytes from perilipin -null animals have an elevated basal rate of lipolysis compared with adipocytes from wild-type mice, but fail to respond maximally to lipolytic stimuli. This defect is downstream of the -adrenergic receptor–adenylyl cyclase complex. Now, we show that HSL is basally associated with lipid droplet surfaces at a low level in perilipin nulls, but that stimulated translocation from the cytosol to lipid droplets is absent in adipocytes derived from embryonic fibroblasts of …