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Articles 183721 - 183750 of 294144

Full-Text Articles in Physical Sciences and Mathematics

Balanced Pod For Linear Pde Robust Control Computations, John R. Singler, Belinda A. Batten Jan 2011

Balanced Pod For Linear Pde Robust Control Computations, 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 nite 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. Convergence theory is given, and numerical results are presented …

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A Model Based Feedback Controller For Wing-Twist Via Piezoceramic Actuation, John R. Singler, Belinda A. Batten Jan 2011

A Model Based Feedback Controller For Wing-Twist Via Piezoceramic Actuation, John R. Singler, Belinda A. Batten

Mathematics and Statistics Faculty Research & Creative Works

In this paper we present a model for a rubber plate with piezoceramic actuators to represent a bioinspired flexible wing. Using a Galerkin based finite element approximation to the system, we compute a linear quadratic based tracking control for piezoelectric actuators placed along both leading and trailing edges. Using these piezoceramic devices, we demonstrate the effectiveness of model based feedback control in achieving a desired wing tip position; this modified shape is analogous to aircraft roll moment generation via wing twist.

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Convergent Snapshot Algorithms For Infinite-Dimensional Lyapunov Equations, John R. Singler Jan 2011

Convergent Snapshot Algorithms For Infinite-Dimensional Lyapunov Equations, John R. Singler

Mathematics and Statistics Faculty Research & Creative Works

We consider two algorithms to approximate the solution Z of a class of stable operator Lyapunov equations of the form AZ + ZA* + BB* = 0. The algorithms utilize time snapshots of solutions of certain linear infinite-dimensional differential equations to construct the approximations. Matrix approximations of the operators a and B are not required and the algorithms are applicable as long as the rank of B is relatively small. The first algorithm produces an optimal low-rank approximate solution using proper orthogonal decomposition. The second algorithm approximates the product of the solution with a few vectors and can be implemented …

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Sub-Supersolution Method In Variational Inequalities With Multivalued Operators Given By Integrals, Vy Khoi Le Jan 2011

Sub-Supersolution Method In Variational Inequalities With Multivalued Operators Given By Integrals, Vy Khoi Le

Mathematics and Statistics Faculty Research & Creative Works

No abstract provided.

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The Impact Of Driving Conditions On Phev Battery Performance, Nathan Christensen, John Patten, Steven Srivastava, Gary P. Nola Jan 2011

The Impact Of Driving Conditions On Phev Battery Performance, Nathan Christensen, John Patten, Steven Srivastava, Gary P. Nola

Green Manufacturing Research Journal

The battery performance of a modified Prius with a 5 kWh plug-in battery was documented for a year to determine the impact of environmental conditions and user attributes on vehicle performance. Both fuel economy and pure electrical efficiency were compared to ambient temperature. The fuel economy has a positive relationship with ambient temperature until approximately 70˚F where the efficiency begins to drop. Electrical performance has a positive linear relationship with ambient temperature. With the emergence of electric vehicles (EVs) and PHEVs from a variety of automotive manufacturers, information on EV and PHEV performance for consumers will become more important.

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Caribbean Acropora Restoration Guide: Best Practices For Propagation And Population Enhancement, Meaghan E. Johnson, Caitlin Lustic, Erich Bartels, Iliana B. Baums, David S. Gilliam, Elizabeth Anne Larson, Diego Lirman, Margaret W. Miller, Ken Nedimyer, S. Schopmeyer Jan 2011

Caribbean Acropora Restoration Guide: Best Practices For Propagation And Population Enhancement, Meaghan E. Johnson, Caitlin Lustic, Erich Bartels, Iliana B. Baums, David S. Gilliam, Elizabeth Anne Larson, Diego Lirman, Margaret W. Miller, Ken Nedimyer, S. Schopmeyer

Marine & Environmental Sciences Faculty Reports

No abstract provided.

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Sampling Methods For Acropora Corals, Other Benthic Coral Reef Organisms, And Marine Debris In The Florida Keys: Field Protocol Manual For 2011-2012 Assessments, Steven Miller, Leanne M. Rutten, Mark Chiappone Jan 2011

Sampling Methods For Acropora Corals, Other Benthic Coral Reef Organisms, And Marine Debris In The Florida Keys: Field Protocol Manual For 2011-2012 Assessments, Steven Miller, Leanne M. Rutten, Mark Chiappone

Marine & Environmental Sciences Faculty Reports

The 2011-2012 sampling of Acropora corals, other coral reef benthic invertebrates, and marine debris in the Florida Keys National Marine Sanctuary (FKNMS) is being undertaken as a spatially intensive effort to provide updated population distribution and abundance information. The particular focus of surveys in the Florida Keys, as well as in the U.S. Caribbean (Puerto Rico and the U.S.V.I.), concerns the habitat distribution, colony density, size, condition, and population abundance of Acropora corals. Surveys in the Florida Keys also include assessments of urchins, mollusks, anemones, corallimorpharians, and marine debris. These additional assessments are relatively fast and easy to perform. Annual …

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Modification Of Turbulence At The Air-Sea Interface Due To The Presence Of Surfactants And Implications For Gas Exchange. Part I: Laboratory Experiment, Alexander Soloviev, S. Matt, Mikhail Gilman, H. Huhnerfuss, Brian K. Haus, D. Jeong, I. Savelyev, Mark A. Donelan Jan 2011

Modification Of Turbulence At The Air-Sea Interface Due To The Presence Of Surfactants And Implications For Gas Exchange. Part I: Laboratory Experiment, Alexander Soloviev, S. Matt, Mikhail Gilman, H. Huhnerfuss, Brian K. Haus, D. Jeong, I. Savelyev, Mark A. Donelan

Marine & Environmental Sciences Faculty Books and Book Chapters

The air-sea gas transfer of gases like CO2 is substantiallydetermined bythe properties of the aqueous diffusion sublayer and free-surface turbulent boundarylayer. Little is known about the effect of surfactants on turbulence in the near-surface layer of the ocean. In order to investigate the effect of surfactants on turbulent exchanges below the air-sea interface, we have conducted a series of laboratoryexperiments at the UM RSMAS Air-Sea Interaction Saltwater Tank (ASIST) facility. Results from these experiments demonstrate that the surfactant monolayer suppresses turbulence and reduces drag below the water surface and increases the surface drift velocity. This effect is important for parameterization …

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Spring 2011, Nsu Oceanographic Center Jan 2011

Spring 2011, Nsu Oceanographic Center

Currents

No abstract provided.

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Generation Of Isolated Attosecond Extreme Ultraviolet Pulses Employing Nanoplasmonic Field Enhancement: Optimization Of Coupled Ellipsoids, S. L. Stebbings, F. Süßmann, Y-Y Yang, A. Scrinzi, Maxim Durach, Anastasia Rusina, Mark I. Stockman, Matthias F. Kling Jan 2011

Generation Of Isolated Attosecond Extreme Ultraviolet Pulses Employing Nanoplasmonic Field Enhancement: Optimization Of Coupled Ellipsoids, S. L. Stebbings, F. Süßmann, Y-Y Yang, A. Scrinzi, Maxim Durach, Anastasia Rusina, Mark I. Stockman, Matthias F. Kling

Anastasia Rusina

The production of extreme ultraviolet (XUV) radiation via nanoplasmonic field-enhanced high-harmonic generation (HHG) in gold nanostructures at MHz repetition rates is investigated theoretically in this paper. Analytical and numerical calculations are employed and compared in order to determine the plasmonic fields in gold ellipsoidal nanoparticles. The comparison indicates that numerical calculations can accurately predict the field enhancement and plasmonic decay, but may encounter difficulties when attempting to predict the oscillatory behavior of the plasmonic field. Numerical calculations for coupled symmetric and asymmetric ellipsoids for different carrier-envelope phases (CEPs) of the driving laser field are combined with time-dependent Schrödinger equation simulations …

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Generation Of Isolated Attosecond Extreme Ultraviolet Pulses: Optimization Of Coupled Ellipsoids, Sarah L. Stebbings, F. Süßmann, Y-Y Yang, A. Scrinzi, Maxim Durach, Anastasia Rusina, Mark I. Stockman, Matthias F. Kling Jan 2011

Generation Of Isolated Attosecond Extreme Ultraviolet Pulses: Optimization Of Coupled Ellipsoids, Sarah L. Stebbings, F. Süßmann, Y-Y Yang, A. Scrinzi, Maxim Durach, Anastasia Rusina, Mark I. Stockman, Matthias F. Kling

Maxim Durach

The production of extreme ultraviolet (XUV) radiation via nanoplasmonic field-enhanced high-harmonic generation (HHG) in gold nanostructures at MHz repetition rates is investigated theoretically in this paper. Analytical and numerical calculations are employed and compared in order to determine the plasmonic fields in gold ellipsoidal nanoparticles. The comparison indicates that numerical calculations can accurately predict the field enhancement and plasmonic decay, but may encounter difficulties when attempting to predict the oscillatory behavior of the plasmonic field. Numerical calculations for coupled symmetric and asymmetric ellipsoids for different carrier-envelope phases (CEPs) of the driving laser field are combined with time-dependent Schrödinger equation simulations …

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Disassembly Of Preformed Amyloid Ss Fibrils By Small Organofluorine Molecules, Abha Sood, Abid Shaikh, Catharine Sauer, Samson Hailemichael, Michelle Foster, Béla Török, Marianna Török Jan 2011

Disassembly Of Preformed Amyloid Ss Fibrils By Small Organofluorine Molecules, Abha Sood, Abid Shaikh, Catharine Sauer, Samson Hailemichael, Michelle Foster, Béla Török, Marianna Török

Abid Shaikh

A potential therapeutic approach for Alzheimer’s disease is to reduce the amount of toxic amyloid-beta oligomers and fibrillar amyloid plaques. In order to contribute to this approach the ability of small organofluorine compounds that were previously reported as successful inhibitors of fibrillogenesis to destabilize preformed fibrils of the amyloid-beta peptide was studied. These organofluorine molecules including chiral compounds were tested in vitro using standard methods based on Thioflavin-T (THT) fluorescence spectroscopy, atomic force microscopy (AFM) and Fourier-transform infrared spectroscopy (FTIR). It was observed that 5′-halogen substituted 3,3,3-trifluoromethyl-2-hydroxyl-(indol-3-yl)-propionic acid esters showed significant activity in the disassembly of the preformed fibrils. Since …

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Boronic Acid Functionalized Peptidyl Synthetic Lectins: Combinatorial Library Design, Peptide Sequencing, And Selective Glycoprotein Recognition, Kevin L. Bicker, Jing Sun, John J. Lavigne, Paul R. Thompson Jan 2011

Boronic Acid Functionalized Peptidyl Synthetic Lectins: Combinatorial Library Design, Peptide Sequencing, And Selective Glycoprotein Recognition, Kevin L. Bicker, Jing Sun, John J. Lavigne, Paul R. Thompson

Jing Sun

Aberrant glycosylation of cell membrane and secreted glycoproteins is a hallmark of various disease states, including cancer. The natural lectins currently used in the recognition of these glycoproteins are costly, difficult to produce, and unstable toward rigorous use. Herein we describe the design and synthesis of several boronic acid functionalized peptide-based synthetic lectin (SL) libraries, as well as the optimized methodology for obtaining peptide sequences of these SLs. SL libraries were subsequently used to identify SLs with as high as 5-fold selectivity for various glycoproteins. SLs will inevitably find a role in cancer diagnostics, given that they do not suffer …

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A Comparative Integrated Geophysical Study Of Horseshoe Chimney Cave, Colorado Bend State Park, Texas, Wesley A. Brown, Kevin W. Stafford, Melinda G. Shaw-Faulkner, Andy Grubbs Jan 2011

A Comparative Integrated Geophysical Study Of Horseshoe Chimney Cave, Colorado Bend State Park, Texas, Wesley A. Brown, Kevin W. Stafford, Melinda G. Shaw-Faulkner, Andy Grubbs

Faculty Publications

An integrated geophysical study was performed over a known cave in Colorado Bend State Park (CBSP), Texas, where shallow karst features are common within the Ellenberger Limestone. Geophysical survey such as microgravity, ground penetrating radar (GPR), direct current (DC) resistivity, capacitively coupled (CC) resistivity, induced polarization (IP) and ground conductivity (GC) measurements were performed in an effort to distinguish which geophysical method worked most effectively and efficiently in detecting the presence of subsurface voids, caves and collapsed features. Horseshoe Chimney Cave (HCC), which is part of a larger network of cave systems, provides a good control environment for this research. …

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Thermal Characterization Of The Ellenberger Karst Springs, Colorado Bend State Park, Texas [Abstract], Sherri Dornak, Katie Mitchell, Jessica De Leon, Kevin W. Stafford Jan 2011

Thermal Characterization Of The Ellenberger Karst Springs, Colorado Bend State Park, Texas [Abstract], Sherri Dornak, Katie Mitchell, Jessica De Leon, Kevin W. Stafford

Faculty Presentations

No abstract provided.

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Cooper’S Hawk Nest Site Characteristics In The Pineywoods Region, Richard R. Schaefer, D. Craig Rudolph, Josh B. Pierce, Jesse F. Fagan Jan 2011

Cooper’S Hawk Nest Site Characteristics In The Pineywoods Region, Richard R. Schaefer, D. Craig Rudolph, Josh B. Pierce, Jesse F. Fagan

Faculty Publications

Early accounts describe the Cooper’s Hawk (Accipiter cooperi) as a species in decline in much of North America during the early twentieth century (Bent 1937), particularly when in close proximity to humans (Eaton 1914). This decreasing population trend continued to be recognized later in the century in both Texas (Oberholser 1974) and Louisiana (Lowery 1974). Shooting and trapping during the first half of the 1900s, and pesticide use (especially DDT) after World War II are suggested as primary causes of the decline (Henny and Wight 1972, Bednarz et al. 1990). The Migratory Bird Treaty Act of 1972 and the ban …

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The Changing Roles Of Natural Resource Professionals: Providing Tools To Students To Teach The Public About Fire, Pat Stephens Williams, Brian Oswald, Karen Stafford, Justice Jones, David Kulhavy Jan 2011

The Changing Roles Of Natural Resource Professionals: Providing Tools To Students To Teach The Public About Fire, Pat Stephens Williams, Brian Oswald, Karen Stafford, Justice Jones, David Kulhavy

Faculty Publications

The Arthur Temple College of Forestry and Agriculture (ATCOFA) at Stephen F. Austin State University is taking a proactive stance toward preparing forestry students to work closely with the public on fire planning in wildland-urban interface areas. ATCOFA's incorporation of the "Changing Roles" curriculum provides lessons on how natural resource managers' roles are (1) different than they used to be, and (2) ever-evolving. The undergraduate Forestry Field Station summer program at the University's Piney Woods Conservation Center now emphasizes the importance and challenges of working with the public. The program brings practicing professionals from the Texas Forest Service to describe …

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Physics In A Glitter Ball, Walter Trikosko Jan 2011

Physics In A Glitter Ball, Walter Trikosko

Faculty Publications

Maui Toys' Water Bouncer (Fig. 1) is a water‐filled ball containing glitter. Buy one and put it on your desk and students can't keep their hands off of it. Pitch the ball in the air giving it a quick spin. When you catch it you will see a sparkling vortex. Twist the ball around different ways and the angular momentum of the fluid keeps the axis of the glitter vortex fixed in one direction.

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Apparatus For Demonstrating Longitudinal Wave Pulses, Walter L. Trikosko, Thomas O. Callaway Jan 2011

Apparatus For Demonstrating Longitudinal Wave Pulses, Walter L. Trikosko, Thomas O. Callaway

Faculty Publications

For live classroom demonstrations there are a number of devices that have been used to simulate waves. Some are based upon a design produced by E. S. Ritchie & Sons1 and consist of rods and cams that are activated by turning a crank.2,3 These devices show what transverse and longitudinal waves look like, but they do not allow for the free manipulation of wave parameters and observations of the changes that take place. A simple device can be constructed using elastic bands and straws4 to demonstrate properties of transverse waves.

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Sfa Weather Station - Monthly And Annual Rainfall - 1901-2011, Arthur Temple College Of Forestry And Agriculture, Stephen F. Austin State University Jan 2011

Sfa Weather Station - Monthly And Annual Rainfall - 1901-2011, Arthur Temple College Of Forestry And Agriculture, Stephen F. Austin State University

Weather Station Data

Monthly and annual rainfall statistics for the years 1901 to 2011.

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Sfa Weather Station - Monthly And Annual Raindays - 1901-2011, Arthur Temple College Of Forestry And Agriculture, Stephen F. Austin State University Jan 2011

Sfa Weather Station - Monthly And Annual Raindays - 1901-2011, Arthur Temple College Of Forestry And Agriculture, Stephen F. Austin State University

Weather Station Data

Monthly and annual raindays for the years 1901 to 2011.

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Sfa Weather Station - Monthly And Annual Mean Minimum Air Temperature 1901-2011, Arthur Temple College Of Forestry And Agriculture, Stephen F. Austin State University Jan 2011

Sfa Weather Station - Monthly And Annual Mean Minimum Air Temperature 1901-2011, Arthur Temple College Of Forestry And Agriculture, Stephen F. Austin State University

Weather Station Data

Monthly and annual mean minimum air temperature statistics for the years 1901 to 2011.

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Sfa Weather Station - Maximum Daily Rainfall - 1901-2011, Arthur Temple College Of Forestry And Agriculture, Stephen F. Austin State University Jan 2011

Sfa Weather Station - Maximum Daily Rainfall - 1901-2011, Arthur Temple College Of Forestry And Agriculture, Stephen F. Austin State University

Weather Station Data

Maximum daily rainfall statistics from 1901 to 2011.

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Sfa Weather Station - Monthly And Annual Mean Air Temperature - 1901-2011, Arthur Temple College Of Forestry And Agriculture, Stephen F. Austin State University Jan 2011

Sfa Weather Station - Monthly And Annual Mean Air Temperature - 1901-2011, Arthur Temple College Of Forestry And Agriculture, Stephen F. Austin State University

Weather Station Data

Monthly and annual mean air temperature statistics for the years 1901 to 2011.

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Sfa Weather Station - Monthly And Annual Mean Maximum Air Temperature - 1901-2011, Arthur Temple College Of Forestry And Agriculture, Stephen F. Austin State University Jan 2011

Sfa Weather Station - Monthly And Annual Mean Maximum Air Temperature - 1901-2011, Arthur Temple College Of Forestry And Agriculture, Stephen F. Austin State University

Weather Station Data

Monthly and annual mean maximum air temperature for the years 1901 to 2011.

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Sfa Weather Station - Daily Rainfall - 1901-2011, Arthur Temple College Of Forestry And Agriculture, Stephen F. Austin State University Jan 2011

Sfa Weather Station - Daily Rainfall - 1901-2011, Arthur Temple College Of Forestry And Agriculture, Stephen F. Austin State University

Weather Station Data

Daily rainfall statistics for the years 1901 to 2011.

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Sfa Weather Station - Minimum Daily Air Temperature - 1901-2011, Arthur Temple College Of Forestry And Agriculture, Stephen F. Austin State University Jan 2011

Sfa Weather Station - Minimum Daily Air Temperature - 1901-2011, Arthur Temple College Of Forestry And Agriculture, Stephen F. Austin State University

Weather Station Data

Minimum daily air temperature statistics from 1901 to 2011.

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Sfa Weather Station - Maximum Daily Air Temperature - 1901-2011, Arthur Temple College Of Forestry And Agriculture, Stephen F. Austin State University Jan 2011

Sfa Weather Station - Maximum Daily Air Temperature - 1901-2011, Arthur Temple College Of Forestry And Agriculture, Stephen F. Austin State University

Weather Station Data

Maximum daily air temperature for the years 1901 to 2011.

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Photosensitizer Drug Delivery Via An Optical Fiber, Matibur Zamadar, Goutam Ghosh, Adaic Kapillai Mahendran, Mihaela Minnis, Bonnie I. Kruft, Ashwini Ghogare, David Aebisher, Alexander Greer Jan 2011

Photosensitizer Drug Delivery Via An Optical Fiber, Matibur Zamadar, Goutam Ghosh, Adaic Kapillai Mahendran, Mihaela Minnis, Bonnie I. Kruft, Ashwini Ghogare, David Aebisher, Alexander Greer

Faculty Publications

: An optical fiber has been developed with a maneuverable miniprobe tip that sparges O2 gas and photodetaches pheophorbide (sensitizer) molecules. Singlet oxygen is produced at the probe tip surface which reacts with an alkene spacer group releasing sensitizer upon fragmentation of a dioxetane intermediate. Optimal sensitizer photorelease occurred when the probe tip was loaded with 60 nmol sensitizer, where crowding of the pheophorbide molecules and self-quenching were kept to a minimum. The fiber optic tip delivered pheophorbide molecules and singlet oxygen to discrete locations. The 60 nmol sensitizer was delivered into petrolatum; however, sensitizer release was less efficient in …

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Dft/Td-Dft Investigation Of Optical Absorption Spectra, Electron Affinities, And Ionization Potentials Of Mono-Nitrated Benzanthrones [Abstract], Kefa Karimu Onchoke Jan 2011

Dft/Td-Dft Investigation Of Optical Absorption Spectra, Electron Affinities, And Ionization Potentials Of Mono-Nitrated Benzanthrones [Abstract], Kefa Karimu Onchoke

Faculty Publications

No abstract provided.

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