Physical Sciences and Mathematics Commons^™

Crystal Field Effects On The Reactivity Of Aluminum-Copper Cluster Anions, Patrick J. Roach, W. Hunter Woodward, Arthur C. Reber, Shiv N. Khanna, A. W. Castleman Jr.

Physics Publications

The limits and useful modifications of the jellium model are of great interest in understanding the properties of metallic clusters, especially involving bimetallic systems. We have measured the relative reactivity of CuAl−n clusters (n=11–34) with O2. An odd-even alternation is observed that is in accordance with spin-dependant etching, and CuAl−22is observed as a “magic peak.” The etching resistance of CuAl−22 is explained by an unusually large splitting of the 2D10 subshell that occurs because of a geometric distortion of the cluster that may also be understood as a crystal field splitting of the superatomic orbitals.

First-Principles Study Of Hydrogen Adsorption In Metal-Doped Cof-10, Miao Miao Wu, Qian Wang, Qiang Sun, Puru Jena, Yoshiyuki Kawazoe

Physics Publications

Covalent organic frameworks (COFs), due to their low-density, high-porosity, and high-stability, have promising applications in gas storage. In this study we have explored the potential of COFs doped with Li and Ca metal atoms for storing hydrogen under ambient thermodynamic conditions. Using density functional theory we have performed detailed calculations of the sites Li and Ca atoms occupy in COF-10 and their interaction with hydrogen molecules. The binding energy of Li atom on COF-10 substrate is found to be about 1.0 eV and each Li atom can adsorb up to three H2 molecules. However, at high concentration, Li atoms cluster …

Negative Ions Of Transition Metal-Halogen Clusters, Kalpataru Pradhan, Gennady L. Gutsev, Purusottam Jena

Physics Publications

A systematic density functional theory based study of the structure and spectroscopic properties of neutral and negatively chargedMXn clusters formed by a transition metal atom M (M=Sc,Ti,V) and up to seven halogen atoms X (X=F,Cl,Br) has revealed a number of interesting features: (1) Halogen atoms are bound chemically to Sc, Ti, and V for n≤nmax, where the maximal valence nmax equals to 3, 4, and 5 for Sc, Ti, and V, respectively. For n>nmax, two halogen atoms became dimerized in the neutral species, while dimerization begins at n=5, 6, and 7 for negatively charged clusters containing Sc, Ti, and …

Electronic Structure And Properties Of Isoelectronic Magic Clusters: Al13x (X=H,Au,Li,Na,K,Rb,Cs), Yeon Jae Ko, Anisha Shakya, Haopeng Wang, Andrej Grubisic, Weijun Zheng, Matthias Gotz, Gerd Gantefor, Kit H. Bowen, Puru Jena, Boggavarapu Kiran

Physics Publications

The equilibrium structure, stability, and electronic properties of the Al13X (X=H,Au,Li,Na,K,Rb,Cs) clusters have been studied using a combination of photoelectron spectroscopy experiment and density functional theory. All these clusters constitute 40 electron systems with 39 electrons contributed by the 13 Al atoms and 1 electron contributed by each of the X (X=H,Au,Li,Na,K,Rb,Cs) atom. A systematic study allows us to investigate whether all electrons contributed by the X atoms are alike and whether the structure, stability, and properties of all the magic clusters are similar. Furthermore, quantitative agreement between the calculated and the measured electron affinities and vertical detachment energies enable …

Enhanced Magnetic Moments Of Alkali Metal Coated Sc Clusters: New Magnetic Superatoms, Kalpataru Pradhan, J. Ulises Reveles, Prasenjit Sen, S. N. Khanna

Physics Publications

It is shown that the magnetic moments of Sc atoms can be significantly enhanced by combining them with alkali atoms. We present results of first principles electronic structure calculations of ScNan (1≤n≤12) clusters that indicate that a ScNa12 cluster consisting of a Sc atom surrounded by 12 Na atoms forming a compact icosahedral structure has a spin magnetic moment of 3μB that is three times that of an isolated Sc atom. This unusual behavior is analyzed in terms of the filling of the supershells 1S, 1P,… controlled by the nature and size of the alkali atoms and the more localized …

Magnetic Moment And Local Moment Alignment In Anionic And/Or Oxidized Fen Clusters, D. R. Roy, R. Robles, S. N. Khanna

Physics Publications

First principles studies on the ground statestructure, binding energy, spin multiplicity, and the noncollinearity of local spin moments in Fen and Fen− clusters and their oxides, viz., FenO2and FenO2− have been carried out within a density functional formalism. The ground states of Fen and Fen− clusters have collinear spins with a magnetic moment of around 3.0 μB per atom. The O2 molecule is found to be dissociatively absorbed and its most significant effect on spin occurs in Fe2, where Fe2O2 and Fe2O2− show antiferromagnetic and noncollinear spin arrangements, respectively. The calculated adiabatic electron affinity and the vertical transitions from the …

Structures Of Neutral And Anionic Au16 Clusters Revisited, Gang Chen, Qian Wang, Qiang Sun, Yoshiyuki Kawazoe, Puru Jena

Physics Publications

Using the density functional theory and generalized gradient approximation for exchange and correlation potential, we have performed an extensive search to obtain the ground stategeometries of both neutral and anionic Au16 cluster by considering over 200 low lying isomers. For the neutral Au16 cluster we found a new Td compact structure to be the lowest energy configuration, which is nearly degenerate in total energy with the previously reported Cs and C2v noncage structures. While the Au16− cluster, in agreement with previous calculations, is found to have a Td hollow cage structure, an isomer with a planar structure is found to …

A Trusted Storage System For The Cloud, Sushama Karumanchi

University of Kentucky Master's Theses

Data stored in third party storage systems like the cloud might not be secure since confidentiality and integrity of data are not guaranteed. Though cloud computing provides cost-effective storage services, it is a third party service and so, a client cannot trust the cloud service provider to store its data securely within the cloud. Hence, many organizations and users may not be willing to use the cloud services to store their data in the cloud until certain security guarantees are made. In this thesis, a solution to the problem of securely storing the client’s data by maintaining the confidentiality and …

Assessment Of Groundwater Quality In A Remediated Abandoned Feedlot, Henderson County, Kentucky: Data Report, E. Glynn Beck, James S. Dinger, John Grove, Eugenia Pena-Yewtukhiw

Information Circular--KGS

A three-phase project investigated the influence of past and present agricultural practices on groundwater resources in the Western Kentucky Coal Field. Phase III concentrated on an abandoned dairy feedlot that had been remediated. Results of phase III analyses are presented in this report.

Noncompliance With Public Health Service (Phs) Policy On Humane Care And Use Of Laboratory Animals: An Exploratory Analysis, Leah M. Gomez, Kathleen Conlee, Martin Stephens

Laboratory Experiments Collection

The National Institutes of Health (NIH) is a major biomedical research-funding body in the United States. Approximately 40% of NIH-funded research involves experimentation on nonhuman animals (Monastersky, 2008). Institutions that conduct animal research with NIH funds must adhere to the Public Health Service (PHS) care and use standards of the Office of Laboratory Animal Welfare (OLAW, 2002a). Institutions deviating significantly from the PHS’s animal care and use standards must report these incidents to the NIH’s OLAW. This study is an exploratory analysis of all the significant deviations reported by animal-research facilities to OLAW during a 3-month period. The study identifies …

The Jets Of Tev Blazars At Higher Resolution: 43 Ghz And Polarimetric Vlba Observations From 2005-2009, B. Glenn Piner, Philip G. Edwards

Physics

We present 23 new VLBA images of the six established TeV blazars Markarian 421, Markarian 501, H 1426+428, 1ES 1959+650, PKS 2155-304, and 1ES 2344+514, obtained from 2005 to 2009. Most images were obtained at 43 GHz, and they reveal the parsec-scale structures of three of these sources (1ES 1959+650, PKS 2155-304, and 1ES 2344+514) at factors of two to three higher resolution than has previously been attained. Most of the remaining images map the linear polarization structures at a lower frequency of 22 GHz. We discuss the transverse structures of the jets as revealed by the high-frequency …

Nonlinear Model Reduction Using Group Proper Orthogonal Decomposition, Benjamin T. Dickinson, John R. Singler

Mathematics and Statistics Faculty Research & Creative Works

We propose a new method to reduce the cost of computing nonlinear terms in projec- tion based reduced order models with global basis functions. We develop this method by extending ideas from the group nite element (GFE) method to proper orthogonal decomposition (POD) and call it the group POD method. Here, a scalar two-dimensional Burgers' equation is used as a model problem for the group POD method. Numerical results show that group POD models of Burgers' equation are as accurate and are computationally more e cient than standard POD models of Burgers' equation.

Optimality Of Balanced Proper Orthogonal Decomposition For Data Reconstruction, John R. Singler

Mathematics and Statistics Faculty Research & Creative Works

Proper orthogonal decomposition (POD) finds an orthonormal basis yielding an optimal reconstruction of a given dataset. We consider an optimal data reconstruction problem for two general datasets related to balanced POD, which is an algorithm for balanced truncation model reduction for linear systems. We consider balanced POD outside of the linear systems framework, and prove that it solves the optimal data reconstruction problem. the theoretical result is illustrated with an example.

Weyl-Titchmarsh Theory For Hamiltonian Dynamic Systems, Shurong Sun, Shaozhu Chen, Martin Bohner

Mathematics and Statistics Faculty Research & Creative Works

We establish the Weyl-Titchmarsh theory for singular linear Hamiltonian dynamic systems on a time scale T , which allows one to treat both continuous and discrete linear Hamiltonian systems as special cases for T= ℝ and T= ℤ within one theory and to explain the discrepancies between these two theories. This paper extends the Weyl-Titchmarsh theory and provides a foundation for studying spectral theory of Hamiltonian dynamic systems. These investigations are part of a larger program which includes the following: (i) M(λ) theory for singular Hamiltonian systems, (ii) on the spectrum of Hamiltonian systems, (iii) on boundary value problems for …

Balanced Pod Algorithm For Robust Control Design For Linear Distributed Parameter Systems, John R. Singler, Belinda A. Batten

Mathematics and Statistics Faculty Research & Creative Works

A mathematical model of a physical system is never perfect; therefore, robust control laws are necessary for guaranteed stabilization of the nominal model and also "nearby" systems, including hopefully the actual physical system. We consider the computation of a robust control law for large-scale finite dimensional linear systems and a class of linear distributed parameter systems. The controller is robust with respect to left coprime factor perturbations of the nominal system. We present an algorithm based on balanced proper orthogonal decomposition to compute the nonstandard features of this robust control law. Numerical results are presented for a convection diffusion partial …

Computational Issues In Sensitivity Analysis For 1d Interface Problems, L. G. Davis, John R. Singler

Mathematics and Statistics Faculty Research & Creative Works

This paper is concerned with the construction of accurate and e cient computational algorithms for the numerical approximation of sensitivities with respect to a parameter dependent interface location. Motivated by sensitivity analysis with respect to piezoelectric actuator placement on an

Boundary Data Maps For Schrödinger Operators On A Compact Interval, Stephen L. Clark, Fritz Gesztesy, M. Mitrea

Mathematics and Statistics Faculty Research & Creative Works

We provide a systematic study of boundary data maps, that is, 2 x 2 matrix-valued Dirichlet-to-Neumann and more generally, Robin-to-Robin maps, associated with one-dimensional Schrödinger operators on a compact interval [0, R] with separated boundary conditions at 0 and R. Most of our results are formulated in the non-self-adjoint context. Our principal results include explicit representations of these boundary data maps in terms of the resolvent of the underlying Schrödinger operator and the associated boundary trace maps, Krein-type resolvent formulas relating Schrödinger operators corresponding to different (separated) boundary conditions, and a derivation of the Herglotz property of boundary data maps …

High Accuracy Combination Method For Solving The Systems Of Nonlinear Volterra Integral And Integro-Differential Equations With Weakly Singular Kernels Of The Second Kind, Xiaoming He, Lu Pan, Tao Lü

Mathematics and Statistics Faculty Research & Creative Works

This paper presents a high accuracy combination algorithm for solving the systems of nonlinear Volterra integral and integro-differential equations with weakly singular kernels of the second kind. Two quadrature algorithms for solving the systems are discussed, which possess high accuracy order and the asymptotic expansion of the errors. By means of combination algorithm, we may obtain a numerical solution with higher accuracy order than the original two quadrature algorithms. Moreover an a posteriori error estimation for the algorithm is derived. Both of the theory and the numerical examples show that the algorithm is effective and saves storage capacity and computational …

The Hodrick-Prescott Filter: A Special Case Of Penalized Spline Smoothing, Robert Paige L., A. A. Trindade

Mathematics and Statistics Faculty Research & Creative Works

We prove that the Hodrick-Prescott Filter (HPF), a commonly used method for smoothing econometric time series, is a special case of a linear penalized spline model with knots placed at all observed time points (except the first and last) and uncorrelated residuals. This equivalence then furnishes a rich variety of existing data-driven parameter estimation methods, particularly restricted maximum likelihood (REML) and generalized cross-validation (GCV). This has profound implications for users of HPF who have hitherto typically relied on subjective choice, rather than estimation, for the smoothing parameter. By viewing estimates as roots of an appropriate quadratic estimating equation, we also …

Gronwall-Ouiang-Type Integral Inequalities On Time Scales, Ailian Liu, Martin Bohner

Mathematics and Statistics Faculty Research & Creative Works

We present several Gronwall-OuIang-type integral inequalities on time scales. Firstly, an OuIang inequality on time scales is discussed. Then we extend the Gronwall-type inequalities to multiple integrals. Some special cases of our results contain continuous Gronwall-type inequalities and their discrete analogues. Several examples are included to illustrate our results at the end.

Incorporating Genome Annotation In The Statistical Analysis Of Genomic And Epigenomic Tiling Array Data, Gayla R. Olbricht

Mathematics and Statistics Faculty Research & Creative Works

"A wealth of information and technologies are currently available for the genomewide investigation of many types of biological phenomena. Genomic annotation databases provide information about the DNA sequence of a particular organism and give locations of different types of genomic elements, such as the exons and introns of genes. Microarrays are a powerful type of technology that make use of DNA sequence information to investigate different types of biological phenomena on a genome-wide level. Tiling arrays are a unique type of microarray that provide unbiased, highdensity coverage of a genomic region, making them well suited for many applications, such as …

2010 Tropical Coral Reefs (Appendix 10), Joana Figueiredo

Marine & Environmental Sciences Faculty Reports

SUMMARY

• Coral reef ecosystems are global biodiversity hotspots that depend on the massive calcium carbonate structures mainly deposited by scleractinian (i.e., “hard”) corals. Scleractinian coral distribution is primarily limited by sea-surface temperature, light, depth, ocean pH, sea water salinity, nutrients and sediment loads. These ecosystems are currently threatened by localized stresses such as overfishing and destructive fishing practices, pollution, terrestrial nutrient and sediment run-off, but are increasing impacted by direct and indirect impacts of rising CO2 concentrations and climate change.
• Coral reefs provide a broad range of ecosystems services with high socio-economic value: tourism, fisheries (food and employment), nutrient cycling, …

Standardized Catch Rates Of Sandbar Sharks And Dusky Sharks In The Vims Longline Survey: 1975-2009, Jason G. Romine, Kristene T. Parsons, R. Dean Grubbs, John A. Musick, Tracey Sutton

Marine & Environmental Sciences Faculty Reports

The Virginia Institute of Marine Science has conducted a fishery-independent longline survey during summer months since 1974. Data for sandbar sharks and dusky sharks captured in the survey between 1975 and 2009 are presented. Most of the sandbar sharks encountered by the survey were immature, with females composing almost all of the mature sandbar catch. Almost all dusky sharks captured were immature. Most of the catch since the early 1990’s has been composed of 0-4 year age classes. Nominal and standardized catch rates are presented. CPUE for both species decreased from the early 1980’s to minima in 1992. CPUE then …

Sailfish (Istiophorus Platypterus) Habitat Utilization In The Southern Gulf Of Mexico And Florida Straits With Implications On Vulnerability To Shallow-Set Pelagic Longline Gear, David W. Kerstetter, Shannon Michael Bayse, John E. Graves

Marine & Environmental Sciences Faculty Reports

A total of 19 pop-up satellite archival tags (PSATs) were deployed on sailfish in the southern Gulf of Mexico between 2005 and 2007 aboard a commercial pelagic longline vessel (n = 18) and a recreational rod-and-reel vessel (n = 1). All PSATs were programmed to collect pressure (depth), temperature, and light-level data for 10 days at approximately 90-second intervals. These point-level data were not summarized prior to transmission, allowing the reconstruction of vertical movement patterns. Three tags suggested mortality events and were excluded from subsequent analyses. We present the preliminary data analyses from the remaining 16 PSATs. Sailfish are primarily …

Marine Resources Of The Falklands' Shallow Marine Environment, Karen L. Neely, Paul Brickle, Vladimir Laptikhovsky

Marine & Environmental Sciences Faculty Reports

No abstract provided.

On A Semigroup Variety Of György Pollák, Edmond W. H. Lee

Mathematics Faculty Articles

Let P be the variety of semigroups defined by the identity xyzx = x². By a result of György Pollák, every subvariety of P is finitely based. The present article is concerned with subvarieties of P and the lattice they constitute, where the main result is a characterization of finitely generated subvarieties of P. It is shown that a subvariety of P is finitely generated if and only if it contains finitely many subvarieties, and the identities defining these varieties are described. Specifically, it is decidable when a finite set of identities defines a finitely generated subvariety …

Fall 2010, Nsu Oceanographic Center

Currents

No abstract provided.

Winter 2010, Nsu Oceanographic Center

Currents

No abstract provided.

2010-2011 Nova Southeastern University Undergraduate Student Catalog, Nova Southeastern University

Undergraduate Programs Course Catalogs

No abstract provided.

Dark Matter Halos And Evolution Of Bars In Disk Galaxies: Varying Gas Fraction And Gas Spatial Resolution, Jorge Villa-Vargas, Isaac Schlosman, Clayton Heller

Jorge Villa-Vargas

We conduct numerical experiments by evolving gaseous/stellar disks embedded in live dark matter halos aiming at quantifying the effect of gas spatial resolution and gas content on the bar evolution. Three model sequences have been constructed using different resolutions, and the gas fraction has been varied along each sequence within the range of f_g = 0%-50%, but keeping the disk and halo properties unchanged. We find that the spatial resolution becomes important with an increase in the gas content. For the higher resolution model sequences, we observe a bimodal behavior in the bar evolution with respect to the gas …