Physical Sciences and Mathematics Commons^™

The CuA Center Of A Soluble Domain From Thermus Cytochrome Ba3. An Nmr Investigation Of The Paramagnetic Protein. A Proton Nmr Study Of The Paramagnetic Active Site Of The CuA Variant Of Amicyanin, Richard C. Holz

Chemistry Faculty Research and Publications

No abstract provided.

Temperature Dependence Of Step Density On Vicinal Pb(111), Z. H. Zhang, H. E. Elsayed-Ali

Electrical & Computer Engineering Faculty Publications

The temperature dependence of step density on the vicinal Pb(111) surface is investigated using reflection high-energy electron diffraction. When the temperature is increased from 323 to 590 K. the average terrace width and the average string length at the step edge decrease from 85±25 to 37±16 Å and from 220±33 to 25±8 Å, respectively. Thermal step collapse on the Pb(111) surface near its bulk melting temperature is not observed. Above 530±7 K, the change in the string length at the step edge with temperature becomes small, and the intensity of the (00) beam is significantly decreased. We conclude that partial …

Femtosecond Photoemission Study Of Ultrafast Electron Dynamics In Single-Crystal Au(111) Films, J. Cao, Y. Gao, H. E. Elsayed-Ali, R. J. D. Miller, D. A. Mantell

Electrical & Computer Engineering Faculty Publications

The energy-dependent relaxation of photoexcited electrons has been measured by time-resolved two-photon photoemission spectroscopy on single-crystal Au(111) films with thickness ranging from 150 to 3000 Å. It is found that the energy-dependent relaxation does not show any significant thickness dependence, which indicates that electron transport is a much slower dynamical process in the near-surface region than expected from bulk properties. Furthermore, lifetimes of the photoexcited electrons can be fitted well by the Fermi-liquid theory with a scaling factor plus an effective upper lifetime. This observation enables separation of electron-electron scattering, and to a lesser extent electron-phonon scattering, processes from electron-transport …

How Much Reliability And Yield Is Enough For A Ctbt?, David W. Hafemeister

Physics

No abstract provided.

Biomineralization Of Magnetic Iron Minerals In Bacteria, Richard B. Frankel, Dennis A. Bazylinski, Dirk Schϋler

Physics

Magnetotactic bacteria orient and migrate along magnetic field lines. This ability is based on a submicron assembly of single-magnetic domain iron mineral particles that elegantly solves the problem of how to construct a magnetic dipole that is large enough to be oriented in the geomagnetic field at ambient temperature, yet fit inside a micron-sized cell. The solution is based on the ability of the bacteria to accumulate high concentrations of iron, and control the deposition, size and orientation of a specific iron mineral at specific locations in the cell.

Ion Bernstein Waves Driven By Two Transverse Flow Layers, Mark Anthony Reynolds, G. Ganguli

Publications

The interaction between two narrow layers of E3B flow is investigated, along with their stability properties. The mode frequencies, growth rates, and eigenfunctions are calculated. It is found that the instability due to a single layer is robust to the inclusion of a second layer. Specifically, when the separation between the layers is on the order of the ion-cyclotron radius, there is strong coupling between the two layers and the second layer is destabilizing. In addition, when the flow velocities are in opposite directions a wide variety of modes is possible, including near-zero-frequency modes, resulting in broadband structure in both …

Inversion Of Plasmaspheric Euv Remote Sensing Data From The Stp 72-1 Satellite, R.R. Meier, A.C. Nicholas, J.M. Picone, D.J. Melendez-Alvira, G. Ganguli, Mark Anthony Reynolds, E.C. Roelof

Publications

Observations of the extreme ultraviolet emission of helium ions at 30.4 nm can be used to study the global shape of the plasmasphere and its dynamical response to geomagnetic forcing. In order to retrieve number densities of plasmaspheric He+ from such observations, we have developed a new inversion technique based on discrete inverse theory, which uses the optical data to optimize a parameterized model of the He+ distribution. We apply this inversion technique to several orbits of data obtained from the Naval Research Laboratory extreme ultraviolet photometric experiment launched on the STP 72-1 satellite in October 1972. The inversion is …

Fact Sheet, Yale University Office Of Institutional Research

Fact Sheets

No abstract provided.

Circulation, Vol. 5, No. 2, Center For Coastal Physical Oceanography, Old Dominion University

CCPO Circulation

Winter 1998 issue of CCPO Circulation featuring article "Coastal Oceanographic Research Experiences in Chile"

Heat And Salt Changes On The Continental Shelf West Of The Antarctic Peninsula Between January 1993 And January 1994, John M. Klinck

CCPO Publications

Hydrographic measurements from four cruises between January 1993 and January 1994 over the continental shelf west of the Antarctic Peninsula allow analysis of seasonal changes in heat and salt content of this region. Changes above the permanent pycnocline (about 150 m) follow a seasonal pattern of cooling and increasing in salt from summer to winter and warming and freshening from winter to summer. These near-surface changes expressed as net heating or salting rate, were above 80 W m(-2) and 4 mg salt m(-2) s(-1). The year to year difference was small compared to the seasonal changes. There was no seasonal …

University Of Texas At Tyler Freshman Catalog, 1998-1999, University Of Texas At Tyler

Catalogs

Archives Space instance: https://archivesspace.uttyler.edu/repositories/2/archival_objects/22363

Characterisations Of Slender Groups, Thomas Kelly

Masters

Chapter 1 summarises some necessary results concerning free, divisible, algebraically compact and cotorsion groups. A detailed proof of the well-known result that the Specker group P is ℵ1 free but not free is included and the structure of the quotient group P/S is determined. The basic properties of slender groups are examined and cotorsion groups of cardinality less than or equal to that of the continuum are shown to be epimorphic images of P. Chapter II presents Nunke’s characterisation of slender groups. This approach establishes that homomorphic images of the Specker group P are the direct sum of a cotorsion …

Transitive And Fully Transitive Groups, Steve Files, Brendan Goldsmith

Articles

The notions of transitivity and full transitivity for abelian p-groups were introduced by Kaplansky in the 1950s. Important classes of transitive and fully transitive p-groups were discovered by Hill, among others. Since a 1976 paper by Corner, it has been known that the two properties are independent of one another. We examine how the formation of direct sums of p-groups affects transitivity and full transitivity. In so doing, we uncover a far-reaching class of p-groups for which transitivity and full transitivity are equivalent. This result sheds light on the relationship between the two properties for all p-groups.

Segmentation Of Printed Circuit Board Images Into Basic Patterns, Madhav Moganti, Fikret Ercal

Computer Science Faculty Research & Creative Works

Segmentation is the first and foremost step in the inspection of the printed circuit boards. In this paper a new technique for the segmentation of printed circuit board (PCB) images is presented. The technique basically segments a given PCB into small windows containing primitive PCB subpatterns. The technique proposed exploits the simplicity and the homogeneity of the PCB images and is inherently parallel. A detailed discussion of the experiments and the results obtained is also presented. © 1993 Academic Press.

Evaluation Of Toxicity, Bioavailability And Speciation Of Lead, Zinc And Cadmium In Mine/Mill Wastewaters, Mujde Erten-Unal, Bobby G. Wixson, Nord Gale, Jerry L. Pitt

Civil & Environmental Engineering Faculty Publications

The toxicity of common compounds of lead, cadmium and zinc was evaluated in waters similar to that found in the world's largest lead producing area in Missouri. Static, acute toxicity tests were performed using fathead minnows (Pimephales promelas) and water fleas (Daphnia magna) respectively. Test organisms were subjected to varying amounts of sulfide, carbonate, chloride and sulfate salts of lead, zinc and cadmium mixed in hard, alkaline waters typical to this region. Median lethal concentrations were calculated using nominal versus measured metal concentrations. Measured metal concentrations included four different metal fractionation (extraction/filtration) techniques at different pH …

Kinetic Studies Of The Thermal Decomposition Of Di- And Tri-Organotin Derivatives Of 1-Nitroso-2-Naphthol, Saqib Ali, Moazzam H. Bhatti, Sohail Mahmood, Muhammad Mazhar, M. Saleem Khalid, Nazar Hussain

Turkish Journal of Chemistry

The di- and tri-organotin complexes of general formula R$_2$SnL$_2$ and R$_3$SnL where R = C$_4$H$_9$, C$_6$H$_5$, C$_6$H$_5$CH$_2$, C$_6$H$_{11}$ and L=1-nitroso-2-naphthol, were subjected to thermal decomposition by means of thermogravimetry (TG). The decomposition occurred in steps and the kinetics of every set of reactions were determined using the method described by Coats and Redfern. These results were analysed to establish the decomposition kinetics and hence to calculate activation energies. The activation energies were also determined by applying the method described by Horowitz, which yielded comparable results.

Trace Element Signatures In Otoliths Record Natal River Of Juvenile American Shad (Alosa Sapidissima), Simon R. Thorrold, Cynthia M. Jones, Steven E. Campana, James W. Mclaren, Joseph W. H. Lam

OES Faculty Publications

The elemental composition of fish otoliths may represent a permanent record of the environmental conditions an individual has experienced as trace elements, incorporated into the growing surface of the otolith, reflect the physical and chemical characteristics of the ambient water. We tested the utility of trace element signatures in otoliths as natural tags of the river of origin of juvenile American shad (Alosa sapidissima) collected from the Connecticut, Hudson and Delaware Rivers in August and October 1994. Four elements (K, Mn, Sr, and Ba) showed significant variability among sites within rivers in August, although only Mg showed a …

Stochastic Analysis Of Quality Control Charts Using Integral Equations, Kenneth Adam Scharnagl

College of Graduate Studies: Theses & Dissertations (1964–2006)

No abstract provided.

Thermodynamics And Structure Of Simple Liquid Metals Calculated Using An Analytic Pair Potential, Serap Dalgiç, Seyfettin Dalgiç, M. Tomak

Turkish Journal of Physics

The analytic interatomic pair potential for simple metals is derived from first principles using second order pseudopotential theory by Pettifor and Ward . It is developed using the Heine-Abarenkov pseudopotential for simple metals and applied to the calculations of the structural and thermodynamic properties of liquid metals. The corresponding liquid metal structure is calculated using the random phase approximation and the hypernetted-chain formulation. The long-wavelength limit S(0) of the structure factor of liquid metals using the hard-sphere system as reference is also investigated. The calculated thermodynamic and structural properties using the real space formalism are in better agreement with experimental …

Multiple Scales Method For A Matrix Kdv Equation, Mehmet Naci Özer

Turkish Journal of Physics

In this paper the method of multiple scales is used to derive an integrable matrix non-linear Schrödinger equation (MNLS) as an amplitude equation from the Matrix Korteweg-de Vries equation (MKdV) associated with symmetric spaces. Then the integrability of the MNLS equation is deduced by the derivation of the spectral problem for the MNLS equation from the spectral problem for the MKdV equation.

Space Charge Limited Current In Films Obtained In Glow Discharge Plasma, M.M. Akhmedov, M.K. Kerimov, B.A. Suleimanov, S.A. Mansimov

Turkish Journal of Physics

The electrical current in thin films obtained by the polymerization of acetonitrile in glow discharge on a heated substrate were investigated in order to determine the mechanism of electrical conduction. The results of the field dependence, sample thickness dependence of the dark conductivity, supported by the results of photocurrent measurements, suggest an exponential energy distribution of traps inside the band gap of the polymer.

Eect Of Sintering Time On Sb Added Bipbsrcacuo Superconducting Ceramics, K. Kocabaş

Turkish Journal of Physics

In this study, superconducting Sb doped BiPbSrCaCuO ceramics with a fixed nominal composition were prepared and sintered at 850^oC for different periods. The structural phases of the sintered ceramics were determined by means of the measurements of the resistivity-temperature behaviour and of the XRD analysis. Sb doping along with Pb doping in the BiSrCaCuO ceramics was observed to increase the volume fraction of the high $T_c$ phase, the onset temperature and the critical temperature $T_c$. The critical temperature for the 100 hour sintered sample was 4K higher than that of the 60 hour sintered sample.

A Hierarchical Filtering-Based Monitoring Architecture For Large-Scale Distributed Systems, Ehab Salem Al-Shaer

Computer Science Theses & Dissertations

On-line monitoring is essential for observing and improving the reliability and performance of large-scale distributed (LSD) systems. In an LSD environment, large numbers of events are generated by system components during their execution and interaction with external objects (e.g. users or processes). These events must be monitored to accurately determine the run-time behavior of an LSD system and to obtain status information that is required for debugging and steering applications. However, the manner in which events are generated in an LSD system is complex and represents a number of challenges for an on-line monitoring system. Correlated events axe generated concurrently …

Aerosol Particle Scavenging By Fog And Haze Droplets, Josef Podzimek

Physics Faculty Research & Creative Works

Droplet imprints in thin gelatin layers have been used for the investigation of coarse particles embedded in fog (haze) droplets in comparison to interstitial particles. Droplet samples were taken in less polluted regions of Missouri and Illinois and also in more polluted marine-urban environment in Italy. Considerable differences in particle size distribution and particle location inside the droplets have been found in samples collected on four sampling sites. The deduced relationships can be applied for the description of the aerosol scavenging process in fogs. The pollution of fog (haze) droplets may be related to the droplet mean volume radius and …

Structure And Dynamics Of Few-Nucleon Systems, J. Carlson, R. Schiavilla

Physics Faculty Publications

Few-nucleon physics is a field rich with high-quality experimental data and possibilities for accurate calculations of strongly correlated quantum systems. In this article the authors discuss the traditional model of the nucleus as a system of interacting nucleons and outline many recent experimental results and theoretical developments in the field of few-nucleon physics. The authors describe nuclear structure and spectra, clustering and correlations, elastic and inelastic electromagnetic form factors, low-energy electroweak reactions, and nuclear scattering and response in the quasi-elastic regime. Through a review of the rich body of experimental data and a variety of theoretical developments, a coherent description …

Composition And Environmental Assessment Of Soils From United Arab Emirates, Torfa Alsheba Khames Alsheriani

Theses

The study focuses on the mineral and chemical composition, the textural characters and environmental assessment of some soils from the UAE. About forty soil samples were collected from AI Ain District and the Eastern Mountain District. Soils in AI Ain and its suburb are strongly influenced by the aeolian sedimentation, while those of the Eastern Mountain are formed in narrow valleys strikingly close to ophiolitic hinterland.

The studied soils· are remarkably impoverished in clay size fraction and clay minerals as well. This is due to the impeded chemical weathering under the prevailing arid climate. Corroborative techniques including X-ray diffraction, infrared …

Parametric Software Project Estimating: An Analysis Of Current Practice, Stuart Hope

Theses: Doctorates and Masters

As society and the world economy moves into the second millennium. the service industries involving knowledge workers will continue to increase. Software is the enabling technology that is driving the knowledge industry. As the development of software is mostly a design process, where new artefacts are conceived and built, the prediction of outcomes in the process is fraught with difficulties. Software project estimating is one of the essential Software Engineering techniques that will enable the rationalisation of decision-making regarding software development. Estimates that are more accurate will increase the probability of success and lower the risk. This thesis analyses the …

Patterns Of Organochlorine Pesticide Contamination In Neotropical Migrant Passerines In Relation To Wintering Range And Wintering Habitat, Jeffrey A. Klemens '98

Honors Projects

Seventy-two Neotropical migrant passerines were analyzed for the presence of 17 organochlorine pesticide residues (aldrin; alpha-BHC; beta-BHC; gamma-BHC; delta-BHC; p,p'-DDD; p,p'-DDE; p,p'-DDT; dieldrin; endosulfan I; endosulfan II; endosulfan sulfate; endrin; endrin aldehyde; heptachlor- heptachlor epoxide; methoxychlor) using standard method of gas chromatography applied to bird tissues. Individuals were colIected along the Mississippi River during May 1996 and represent 11 species (Catharus ustulatus; Geothlypis trichas; Protonotaria citrea; Mniotilta varia; Contopus virens; Dendroica petechia; Ernpidonax minimus; Passerina cyanea; Myiarchus crinitus; Vireo gilvus). The contaminants most frequently detected were p,p'-DDE, dieldrin, and heptachlor epoxide. No significant difference was found between male and female …

The Total Synthesis Of A Conformationally Constrained Organophosphorus Analog Of Acetycholine, Justin Mergott '98

Honors Projects

We propose the total synthesis of a conformationally constrained organophosphorus analog of acetylcholine (5, Scheme 5). This compound will contain two crural centers, one being the phosphorus atom and the other being the pyrrolidine ring carbon beta to the phosphorus atom. The chiral beta carbon is conformationally constrained because it is part of the pyrrolidine ring. Studies with such a compound should allow us to make substantial progress towards the clarification of the stereospecificity of AChE inhibition by OP compounds and eventually help us understand more about the structure of the AChE active site. The synthesis begins with Cbz-L-proline methyl …

Remote Sensing Of Commercial Aircraft Emissions, Peter J. Popp, Donald H. Stedman

Fuel Efficiency Automobile Test Publications

No abstract provided.