Physical Sciences and Mathematics Commons^™

Dissociative Electron Attachment To Uracil Deuterated At The N1 And N3 Positions, A. M. Scheer, C. Silvernail, John A. Belot Jr., Gordon A. Gallup, Paul Burrow

Paul Burrow Publications

Deuteration at the nitrogen sites of uracil produces a striking change in the dissociative attachment cross-section at electron energies below 3 eV. In particular, sharp structures observed in uracil are absent or too small to observe. This result, as well as theoretical modeling, supports the earlier assignment of the sharp structure to vibrational Feshbach resonances that decay by tunneling of the N₁ hydrogen atom through the barrier created by the avoided crossing of the dipole bound anion potential surface by that of the lowest ²Σ valence anion state.

Using State-Wide Gis Data To Identify The Coincidence Betwen Sinkholes And Geologic Structure, Lee J. Florea

Lee J Florea, PhD, P.G.

The Kentucky GIS coverage of sinkholes, completed in 2003, consists of 101,176 polygons representing the uppermost closed contour of every karst sinkhole identified using USGS 1:24,000 scale topographic maps. This resource is a useful tool for delineating karst landscapes in Kentucky because karstified limestones underlie 55% of the areal surface of the state. For hydrologic studies, alignments of sinkholes commonly indicate preferential flowpaths for groundwater; and this information aids in large-scale planning and zoning. In this paper, I demonstrate the effectiveness of using this sinkhole coverage as a tool for delimiting structural features of Kentucky.

Synthesis And Characterization Of Highly Amine Functionalized Mesoporous Organosilicas By An “All-In-One” Approach, Rebecca Voss, Arne Thomas, Markus Antonietti, Geoffrey A. Ozin

Rebecca Cademartiri

Mesoporous organosilicas (MOs) represent a promising class of organic–inorganic nanocomposites for a broad range of applications like catalysis, sensing, separation, or microelectronics. Their distinct feature is the presence of organic groups incorporated into the channel walls of a mesoporous structure. Here, we present a convenient “all-in-one” approach using silsesquioxane surfactant precursors for the functionalization of the channel walls with primary amine groups. The monomer is made by a hydroboration/aminolysis sequence on the base of a commercial monomer, with the template bound to the functionalization site by hydroboration and released after silica condensation and aminolysis. This combination ensures both the placement …

A Geodetic Investigation Of Ground Deformation At Yucca Mountain, Southern Nevada, Emma Mccaughey

Publications (YM)

The data from 28 continuous BARGEN GPS stations in the Yucca Mountain region were processed for January 2000 to June 2004. The data have been processed independently using both the GIPSY and GAMIT software packages for quality assurance purposes, yielding an RMS of velocity differences between the solutions of 0.06 mm/yr for the east and 0.10 mm/yr for the north. The velocity solution for the local Yucca Mountain network has a relatively smooth signal showing NW-trending rightlateral shear. The magnitude of the velocity contrast across the local network, from east to west, is 0.95 ± 0.04 mm/yr. The GPS results …

Initial Borehole Accelerometer Array Observations Near The North Portal Of The Esf, David Von Seggern, James N. Brune, Joe Litehiser, Amy J. Smiecinski

Publications (YM)

This report addresses observed ground motions at the site of the proposed surface facilities associated with the designated repository for high-level nuclear waste at Yucca Mountain, Nevada. In 2003 an accelerometer array was installed at three boreholes on the pad of the north portal of the ESF (Exploratory Studies Facility) at Yucca Mountain, Nevada, by the Nevada Seismological Laboratory (NSL). These boreholes, roughly 150 m apart and initially used for extensive geological and geophysical surveys, were ideal locations to measure the subsurface ground motions at the proposed site of surface facilities such as the Waste Handling Building. Such measurements will …

Mass Loading Measurements In Amargosa Valley, John C. Sagebiel, Alan W. Gertler, Amy J. Smiecinski, David Shafer

Publications (YM)

This work will be conducted under Task DRI-FI-001, “Mass Loading Measurements in Amargosa Valley.” The objective of this task is to measure, with known accuracy, the levels of atmospheric mass loading (mass concentration of suspended particulates) accompanying soil surface disturbing activities in Amargosa Valley. Mass loading is used in the biosphere model to calculate inhalation exposure for the human receptor, the maximally reasonably exposed individual (RMEI). The mass loading currently used in the biosphere model is based on literature data from the analog sites rather than on site-specific conditions. This work is subject to the Nevada System of Higher Education …

Extracting Reduced Logic Programs From Artificial Neural Networks, Jens Lehmann, Sebastian Bader, Pascal Hitzler

Computer Science and Engineering Faculty Publications

Artificial neural networks can be trained to perform excellently in many application areas. While they can learn from raw data to solve sophisticated recognition and analysis problems, the acquired knowledge remains hidden within the network architecture and is not readily accessible for analysis or further use: Trained networks are black boxes. Recent research efforts therefore investigate the possibility to extract symbolic knowledge from trained networks, in order to analyze, validate, and reuse the structural insights gained implicitly during the training process. In this paper, we will study how knowledge in form of propositional logic programs can be obtained in such …

Integrating First-Order Logic Programs And Connectionist Systems - A Constructive Approach, Sebastian Bader, Andreas Witzel, Pascal Hitzler

Computer Science and Engineering Faculty Publications

Significant advances have recently been made concerning the integration of symbolic knowledge representation with artificial neural networks (also called connectionist systems). However, while the integration with propositional paradigms has resulted in applicable systems, the case of first-order knowledge representation has so far hardly proceeded beyond theoretical studies which prove the existence of connectionist systems for approximating first-order logic programs up to any chosen precision. Advances were hindered severely by the lack of concrete algorithms for obtaining the approximating networks which were known to exist: the corresponding proofs are not constructive in that they do not yield concrete methods for building …

On The Design Of An Immersive Environment For Security-Related Studies, Yougu Yuan

Dartmouth College Master’s Theses

The Internet has become an essential part of normal operations of both public and private sectors. Many security issues are not addressed in the original Internet design, and security now has become a large concern for networking research and study. There is an imperative need to have an simulation environment that can be used to help study security-related research problems. In the thesis we present our effort to build such an environment: Real-time Immersive Network Simulation Environment (RINSE). RINSE features flexible configuration of models using various networking protocols and real-time user interaction. We also present the Estimate Next Infection (ENI) …

Efficiently Implementing A Large Number Of Ll/Sc Objects, Prasad Jayanti, Srdjan Petrovic

Computer Science Technical Reports

Over the past decade, a pair of instructions called load-linked (LL) and store-conditional (SC) have emerged as the most suitable synchronization instructions for the design of lock-free algorithms. However, current architectures do not support these instructions; instead, they support either CAS (e.g., UltraSPARC, Itanium) or restricted versions of LL/SC (e.g., POWER4, MIPS, Alpha). Thus, there is a gap between what algorithm designers want (namely, LL/SC) and what multiprocessors actually support (namely, CAS or RLL/RSC). To bridge this gap, a flurry of algorithms that implement LL/SC from CAS have appeared in the literature. The two most recent algorithms are due to …

Variation In Glacier Length And Ice Volume Of Rabots Glaciar, Sweden, In Response To Climate Change, 1910–2003, Keith A. Brugger, Kurt A. Refsnider, Matthew F. Whitehill

Geology Publications

Historical records, photographs, maps and measurements were used to determine changes in the length, geometry and volume of Rabots Glaciar, Sweden, in response to a warming that occurred early in the 20th century.

Chromospherically Active Stars. Xxv. Hd 144110=Ev Draconis, A Double-Lined Dwarf Binary, Francis C. Fekel, Gregory W. Henry, Ceteka Lewis

Information Systems and Engineering Management Research Publications

New spectroscopic and photometric observations of HD 144110 have been used to obtain an improved orbital element solution and determine some basic properties of the system. This chromospherically active, double-lined spectroscopic binary has an orbital period of 1.6714012 days and a circular orbit. We classify the components as G5 V and K0 V and suggest that they are slightly metal-rich. The photometric observations indicate that the rotation of HD 144110 is synchronous with the orbital period. Despite the short orbital period, no evidence of eclipses is seen in our photometry.

Impact Of Palmitic Acid Coating On The Water Uptake And Loss Of Ammonium Sulfate Particles, R. M. Garland, M. E. Wise, M. R. Beaver, H. L. Dewitt, A. C. Aiken, J. L. Jimenez, M. A. Tolbert

CUP Faculty Research

While water insoluble organics are prevalent in the atmosphere, it is not clear how the presence of such species alters the chemical and physical properties of atmospheric aerosols. Here we use a combination of FTIR spectroscopy, Transmission Electron Microscopy (TEM) and Aerosol Mass Spectrometry (AMS) to characterize ammonium sulfate particles coated with palmitic acid. Coated aerosols were generated by atomizing pure ammonium sulfate, mixing the particles with a heated flow of nitrogen with palmitic acid vapor, and then flowing the mixture through an in-line oven to create internally mixed particles. The mixing state of the particles was probed using the …

Measurements Of Secondary Organic Aerosol From Oxidation Of Cycloalkenes, Terpenes, And M-Xylene Using An Aerodyne Aerosol Mass Spectrometer, Roya Bahreini, Melita D. Keywood, Nga L. Ng, Varuntida Varutbangkul, Song Gao, Richard C. Flagan, John H. Seinfeld, D. R. Worsnop, J. L. Jimenez

Chemistry and Physics Faculty Articles

The Aerodyne aerosol mass spectrometer (AMS) was used to characterize physical and chemical properties of secondary organic aerosol (SOA) formed during ozonolysis of cycloalkenes and biogenic hydrocarbons and photooxidation of m-xylene. Comparison of mass and volume distributions from the AMS and differential mobility analyzers yielded estimates of “effective” density of the SOA in the range of 0.64−1.45 g/cm³, depending on the particular system. Increased contribution of the fragment at m/z 44, CO₂⁺ ion fragment of oxygenated organics, and higher “Δ” values, based on ion series analysis of the mass spectra, in nucleation experiments …

Applying The Test Of Appurtenance Globally: A New Inventory Of Wide Margin States From Public Domain Data, Dave Monahan, Robert Van De Poll, Sara Cockburn

Center for Coastal and Ocean Mapping

No abstract provided.

Estimating The Parameters Of Semiconductor Lasers Based On Weak Optical Feedback Self-Mixing Interferometry, Jiangtao Xi, Yanguang Yu, Joe F. Chicharo, T. Bosch

Faculty of Informatics - Papers (Archive)

The paper presents a practical approach for measuring the linewidth enhancement factor /spl alpha/ of semiconductor lasers and the optical feedback level factor C in a semiconductor laser with an external cavity. The proposed approach is based on the analysis of the signals observed in an optical feedback self-mixing interferometric system. The parameters /spl alpha/ and C are estimated using a gradient-based optimization algorithm that achieves best data-to-theoretical model match. The effectiveness and accuracy of the method has been confirmed and tested by computer simulations and experiments, which show that the proposed approach is able to estimate /spl alpha/ and …

Sample-Based Cameras For Fast Accurate Reflections, Voicu Popescu, Elisha Sacks, Chunhui Mei

Department of Computer Science Technical Reports

No abstract provided.

Geometry And Magnetism Of L10 Nanostructures, Kory D. Sorge, Ralph Skomski, Maria Daniil, Steven A. Michalski, L. Gao, Jian Zhou, M. Yan, Yucheng Sui, Roger D. Kirby, Sy_Hwang Liou, David J. Sellmyer

Roger Kirby Publications

The fabrication and magnetism of L1₀ nanostructures with different shapes (such as nanoparticles and nanotubes) is investigated. These nanostructures are produced by hydrogen processing and focused ion beam milling. The structures exhibit interesting reversal modes and are of present or potential interest for sensors and imaging, as well as magnetic recording.

Domain-Wall Magnetoresistance Of Co Nanowires, Renat F. Sabirianov, Ashok K. Solanki, J. D. Burton, Sitaram S. Jaswal, Evgeny Y. Tsymbal

Physics Faculty Publications

Using density functional theory implemented within a tight-binding linear muffin-tin orbital method we perform calculations of electronic, magnetic, and transport properties of ferromagnetic free-standing fcc Co wires with diameters up to 1.5 nm. We show that finite-size effects play an important role in these nanowires resulting in oscillatory behavior of electronic charge and the magnetization as a function of the wire thickness, and a nonmonotonic behavior of spin-dependent quantized conductance. We calculate the magnetoresistance (MR) of a domain wall (DW) modeled by a spin-spiral region of finite width sandwiched between two semi-infinite Co wire leads. We find that the DW …

Reply To Comment By Sushil K. Singh On "A Concept Of Maximum Stream Depletion Rate For Leaky Aquifers In Alluvial Valleys", Vitaly A. Zlotnik

Department of Earth and Atmospheric Sciences: Faculty Publications

Vitaly A. Zlotnik's reply to the comment by Sushil K. Singh on Zlotnik's "A concept of maximum stream depletion rate for leaky aquifers in alluvial valleys."

Chlorella Virus-Encoded Deoxyuridine Triphosphatases Exhibit Different Temperature Optima, Yuanzheng Zhang, Hideaki Moriyama, Kohei Homma, James L. Van Etten

Hideaki Moriyama Publications

A putative deoxyuridine triphosphatase (dUTPase) gene from chlorella virus PBCV-1 was cloned, and the recombinant protein was expressed in Escherichia coli. The recombinant protein has dUTPase activity and requires Mg²⁺ for optimal activity, while it retains some activity in the presence of other divalent cations. Kinetic studies of the enzyme revealed a K_m of 11.7 μ M, a turnover k_cat of 6.8 s^-1, and a catalytic efficiency of k_cat/K_m = 5.8 x 10⁵ M^-1 s^-1. dUTPase genes were cloned and expressed from two other chlorella viruses …

Autoionization Of He Atoms By Partially Stripped Ion Impact, Sebastian Otranto, Ronald E. Olson

Physics Faculty Research & Creative Works

A study of the autoionization process induced by partially stripped ion impact is performed. Electron spectra in momentum space are predicted within a classical model for partially stripped ions. The results are compared with those obtained for pure Coulomb-like projectiles. A quantum-mechanical extension of the Barrachina-Macek model is proposed for partially stripped projectiles. Structure on the electron angular distribution arising in quantum and classical treatments is identified and compared. The presence of rainbow scattering interference is observed in the binary ring profile of the outgoing autoionized electrons for positive-ion impact.

A Constructive Proof Of Ky Fan's Generalization Of Tucker's Lemma, Timothy Prescott '02, Francis E. Su

All HMC Faculty Publications and Research

We present a proof of Ky Fan's combinatorial lemma on labellings of triangulated spheres that differs from earlier proofs in that it is constructive. We slightly generalize the hypotheses of Fan's lemma to allow for triangulations of Sⁿ that contain a flag of hemispheres. As a consequence, we can obtain a constructive proof of Tucker's lemma that holds for a more general class of triangulations than the usual version.

Factors Affecting The Phase Separation Of Liquid Crystals From Acrylate-Based Polymer Matrices, Nathan Joseph Crawford

Doctoral Dissertations

The work presented in this dissertation covers the study of phase separation of small-molecule liquid crystals (LC's) from acrylate-based polymer matrices. These materials are used in the construction of polymer dispersed liquid crystals, or PDLC's, an emerging technology with applications ranging from privacy windows to photonic materials.

The first part of this study involves the determination of the effect of increasing polymer molecular weight on the solubility of the LC 4' -octyl-4-biphenyl carbonitrile, or 8CB, in poly(methyl methacrylate), or PMMA. Optical microscopy is used to determine the equilibrium phase diagrams for blends of 8CB and PMMA with weight-average polymer molecular …

Web Mining - The Ontology Approach, Ee Peng Lim, Aixin Sun

Research Collection School Of Computing and Information Systems

The World Wide Web today provides users access to extremely large number of Web sites many of which contain information of education and commercial values. Due to the unstructured and semi-structured nature of Web pages and the design idiosyncrasy of Web sites, it is a challenging task to develop digital libraries for organizing and managing digital content from the Web. Web mining research, in its last 10 years, has on the other hand made significant progress in categorizing and extracting content from the Web. In this paper, we represent ontology as a set of concepts and their inter-relationships relevant to …

Investigating Nickel Partitioning In A Contaminant Aquifer, Suama Ndengu

Masters Theses

Improved prediction of the transport and bioavailability of metals in contaminated sediments demands a better quantitative understanding of how metals partition between aqueous solutions and mineral phases. This research examines the partitioning of nickel in a contaminated aquifer from Grand Rapids, Ml. Contaminated aquifer sediments were examined using the five step Tessier et al. (1979) operationally defined sequential extraction procedure to determine the solid phase distribution of nickel in the aquifer sediments. Models used to guide remediation efforts at the contaminated site assume that Ni behavior can be predicted based on Ni adsorption onto ferrihydrite (HFO). Although sequential extraction results …

Upper Estimates For The Energy Of Solutions Of Nonhomogeneous Boundary Value Problems, Alfonso Castro, Mónica Clapp

All HMC Faculty Publications and Research

We establish upper bounds for the energy of critical levels of the functional associated to a perturbed superlinear elliptic boundary value problem. We show that the perturbed problem satisfies the estimates obtained by Bahri and Lions (1988) for the symmetric problem. We use these estimates to prove the existence of nonradial solutions to a radial elliptic boundary value problem. Our results fill a gap in an earlier paper by Aduén and Castro.

Studies Directed Toward The Synthesis Of Acylated Phloroglucinols, Joseph Allen Burlison

Doctoral Dissertations

The synthesis and application of α-allenyl ketones directed toward the synthesis of polycyclic polyprenylated acylphloroglucinols are described. A functionalized α-allenyl ketone was synthesized in twelve steps starting from 2-methyl-2-cyclohexenome in 24% overall yield. The α’ stereocenter in the α-allenyl ketone was stereoselectively quaternized using a Tsuji allylation, Mukaiyama adol condensation sequence to afford C-1 functionalized allenyl cyclohexanone building blocks. A survey of acetals and reaction conditions for the Mukaiyama reaction suggested that 3-tert-butyldiphenylsiloxypropanal dimethyl acetal could be used, and indeed this reagent in the presence of TiCl₄∙Ti[OCH(CH₃)₂]₄ gave the aldol product …

Age And Quality Of Ground Water And Sources Of Nitrogen In The Surficial Aquifers In Pumpkin Creek Valley, Western Nebraska, 2000, G. V. Steele, J. C. Cannia, S. S. Sibray, V. L. Mcguire

United States Geological Survey: Publications

Ground water is the source of drinking water for the residents of Pumpkin Creek Valley, western Nebraska. In this largely agricultural area, shallow aquifers potentially are susceptible to nitrate contamination. During the last 10 years, ground-water levels in the North Platte Natural Resources District have declined and contamination has become a major problem for the district. In 2000, the U.S. Geological Survey and the North Platte Natural Resources District began a cooperative study to determine the age and quality of the ground water and the sources of nitrogen in the aquifers in Pumpkin Creek Valley.

Water samples were collected from …

Characterizing 3-Chloro-P-Toluidine Hydrochloride On Rough-Hulled Rice And Ethyl-Cellulose-Coated Rice Baits Using High-Performance Liquid Chromatography, Randal S. Stahl, Carol Furcowlow, Jerome C. Hurley, John J. Johnston

United States Department of Agriculture Wildlife Services: Staff Publications

Methods are developed to extract and quantitate the avicide 3-chloro-p-toluidine hydrochloride (CPT HCI) from rough-hulled rice and ethyl-cellulose-coated rice baits using high-performance liquid chromatography. The mobile phase used in the ethyl-cellulose-coated rice matrix method is an acetonitrile(ACN)-phosphate buffer (60:40) at pH 8, and the rough-hulled rice matrix method uses an ACN-phosphate (70:30) buffer at pH 2. Increased retention time is observed for CPT HCI at the higher pH. The two methods have been useful in characterizing different bait formulations in an ongoing pesticide formulation improvement program.