Open Access. Powered by Scholars. Published by Universities.®

Physical Sciences and Mathematics Commons™

Open Access. Powered by Scholars. Published by Universities.®

2007

Discipline
Institution
Keyword
Publication
Publication Type
File Type

Articles 91 - 120 of 6758

Full-Text Articles in Physical Sciences and Mathematics

Evaluation Of Equalization Basins As Initial Treatment For Flue Gas Desulfurization Waters, Meg Iannacone Dec 2007

Evaluation Of Equalization Basins As Initial Treatment For Flue Gas Desulfurization Waters, Meg Iannacone

All Theses

Coal-fired power plants are introducing flue gas desulfurization (FGD) scrubbers to reduce sulfur dioxide and mercury emissions in order to meet air quality standards. FGD scrubber systems utilize a mixture of limestone, water, and organic acids to precipitate sulfur compounds. The resulting FGD water and associated particulates often contain constituents of concern including chlorides, inorganic elements (Hg, As, and Se), and sulfates that must be treated before discharge. Constructed wetland treatment systems, consisting of an equalization basin followed by wetland reactors, present a viable option to efficiently treat FGD waters. Equalization basins are designed to cool and homogenize FGD water …

Go to article

Risk Characterization For Boron And Aquatic Plants And Animals, Basma Damiri Dec 2007

Risk Characterization For Boron And Aquatic Plants And Animals, Basma Damiri

All Theses

In aqueous mixtures, boron can be toxic to plants or animals at relatively low concentrations. Boron may occur at concentrations that can pose risk to plants used in constructed wetland treatment systems designed to treat constituents of concerned in a complex matrix such as flue gas desulfurization water and boron may adversely affect survival, growth, and consequently, plant performance. The three major objectives of this research are: 1) to measure responses of Typha latifolia (seed germination and root and shoot elongation) and Schoenoplectus californicus early seedlings (survival, and shoot and root elongation) to aqueous exposures of boron in diluted FGD …

Go to article

Changes In Severe Thunderstorm Environment Frequency During The 21st Century Caused By Anthropogenically Enhanced Global Radiative Forcing, Robert J. Trapp, Noah S. Diffenbaugh, Harold E. Brooks, Michael E. Baldwin, Eric D. Robinson, Jeremy S. Pal Dec 2007

Changes In Severe Thunderstorm Environment Frequency During The 21st Century Caused By Anthropogenically Enhanced Global Radiative Forcing, Robert J. Trapp, Noah S. Diffenbaugh, Harold E. Brooks, Michael E. Baldwin, Eric D. Robinson, Jeremy S. Pal

Civil and Environmental Engineering Faculty Works

Severe thunderstorms comprise an extreme class of deep convective clouds and produce high-impact weather such as destructive surface winds, hail, and tornadoes. This study addresses the question of how severe thunderstorm frequency in the United States might change because of enhanced global radiative forcing associated with elevated greenhouse gas concentrations. We use global climate models and a high-resolution regional climate model to examine the larger-scale (or “environmental”) meteorological conditions that foster severe thunderstorm formation. Across this model suite, we find a net increase during the late 21st century in the number of days in which these severe thunderstorm environmental conditions …

Go to article

Remote Sensing Sensors And Applications In Environmental Resources Mapping And Modelling, Assefa M. Melesse, Qihao Weng, Prasad S. Thenkbail, Gabriel B. Senay Dec 2007

Remote Sensing Sensors And Applications In Environmental Resources Mapping And Modelling, Assefa M. Melesse, Qihao Weng, Prasad S. Thenkbail, Gabriel B. Senay

Department of Earth and Environment

The history of remote sensing and development of different sensors for environmental and natural resources mapping and data acquisition is reviewed and reported. Application examples in urban studies, hydrological modeling such as land-cover and floodplain mapping, fractional vegetation cover and impervious surface area mapping, surface energy flux and micro-topography correlation studies is discussed. The review also discusses the use of remotely sensed-based rainfall and potential evapotranspiration for estimating crop water requirement satisfaction index and hence provides early warning information for growers. The review is not an exhaustive application of the remote sensing techniques rather a summary of some important applications …

Go to article

Slow-Light Fourier Transform Interferometer, Zhimin Shi, Robert W. Boyd, Ryan M. Camacho, Praveen K. Vudyasetu, John C. Howell Dec 2007

Slow-Light Fourier Transform Interferometer, Zhimin Shi, Robert W. Boyd, Ryan M. Camacho, Praveen K. Vudyasetu, John C. Howell

Mathematics, Physics, and Computer Science Faculty Articles and Research

We describe a new type of Fourier transform (FT) interferometer in which the tunable optical delay between the two arms is realized by using a continuously variable slow-light medium instead of a moving arm as in a conventional setup. The spectral resolution of such a FT interferometer exceeds that of a conventional setup of comparable size by a factor equal to the maximum group index of the slow-light medium. The scheme is experimentally demonstrated by using a rubidium atomic vapor cell as the tunable slow-light medium, and the spectral resolution is enhanced by a factor of approximately 100.

Go to article

A Middle-Ware Level Client Cache For A High Performance Computing I/O Simulator, Michael Bassily Dec 2007

A Middle-Ware Level Client Cache For A High Performance Computing I/O Simulator, Michael Bassily

All Theses

This thesis describes the design and run time analysis of the system level middle-ware cache for Hecios. Hecios is a high performance cluster I/O simulator. With Hecios, we provide a simulation environment that accurately captures the performance characteristics of all the components in a clusterwide parallel file system. Hecios was specifically modeled after PVFS2. It was designed to be extensible and to easily allow for various component modules to be easily replaced by those that model other system types. Built around the OMNeT++ simulation package, Hecios' inner-cluster communication module is easily adaptable to any TCP/IP based protocol and all standard …

Go to article

Deeply Virtual Compton Scattering Off The Neutron, M. Mazouz, Timothy Holmstrom, Jefferson Lab Hall A Collaboration Dec 2007

Deeply Virtual Compton Scattering Off The Neutron, M. Mazouz, Timothy Holmstrom, Jefferson Lab Hall A Collaboration

Chemistry & Physics Faculty Publications

The present experiment exploits the interference between the deeply virtual Compton scattering (DVCS) and the Bethe-Heitler processes to extract the imaginary part of DVCS amplitudes on the neutron and on the deuteron from the helicity-dependent D(e⃗,e′γ)X cross section measured at Q2=1.9  GeV2 and xB=0.36. We extract a linear combination of generalized parton distributions (GPDs) particularly sensitive to Eq, the least constrained GPD. A model dependent constraint on the contribution of the up and down quarks to the nucleon spin is deduced.

Go to article

Substitute Three-Dimensional Perception Using Depth And Colour Sensors, Simon Meers, Koren Ward Dec 2007

Substitute Three-Dimensional Perception Using Depth And Colour Sensors, Simon Meers, Koren Ward

Faculty of Informatics - Papers (Archive)

The development of sensor-actuator systems that can provide the user with perception of the environment without any use of the eyes is a difficult task. Firstly, the sensors must work effectively under differing conditions. Secondly, the actuators (or auditory feedback) must present the environmental information to the user in a manner that is easy to understand. Thirdly, the whole system needs to be compact, efficient and robust to be practical for a blind person to use. This paper firstly reviews current research in the area of substitute vision systems and discusses their limitations. We then provide details of the substitute …

Go to article

Hybrid Image/Model Based Gaze-Contingent Rendering, Hunter Murphy Dec 2007

Hybrid Image/Model Based Gaze-Contingent Rendering, Hunter Murphy

All Dissertations

A non-isotropic hybrid image/model based gaze-contingent rendering technique utilizing ray casting on a GPU is discussed. Empirical evidence derived from human subject experiments indicates an inverse relationship between a peripherally degraded scene's high-resolution inset size and mean search time, a trend consistent with existing image-based and model-based techniques. In addition, the data suggest that maintaining a target's silhouette edges decreases search times when compared to targets with degraded edges. Benefits of the hybrid technique include simplicity of design and parallelizability, both conducive to GPU implementation.

Go to article

Lithium-Conducting Ionic Melt Electrolytes From Oligomeric Ethylene Glycols: Synthesis And Characterization, Boutros Hallac Dec 2007

Lithium-Conducting Ionic Melt Electrolytes From Oligomeric Ethylene Glycols: Synthesis And Characterization, Boutros Hallac

All Dissertations

Commercial lithium ion cells consist of electrolytes that undergo salt concentration polarization which is acute upon high discharge currents. This type of polarization occurs as a result of the mobility of more than one ionic species in the presence of an electric field. One way to overcome it is by employing a material that would allow the mobility of one ionic species. This thesis will describe the synthesis and characterization of several fluorosulfonimide and fluorosulfonate based ionic liquids/melts as electrolytes having lithium as the only mobile ion. These materials were prepared by the nucleophilic addition reaction of a deprotonated polyether …

Go to article

Development Of Fullerene Based Sturctures For Photovoltaic And Electronic Applications, Amit Palkar Dec 2007

Development Of Fullerene Based Sturctures For Photovoltaic And Electronic Applications, Amit Palkar

All Dissertations

Solar energy can be envisioned as a long term alternative to rapidly depleting fossil fuels. The energy from the sun can be harnessed by constructing donor-acceptor (D-A) type devices where the incident photon induces the transfer of an electron from the donor to the acceptor. If recombination is prevented, this electron can then be channeled through an external circuit, thus leading to the generation of photocurrent. Porphyrins, which are the naturally occurring pigments in photosynthesis, have been widely established as donors while fullerenes, such as C60 and C70 , due to their unique electron accepting properties, have been …

Go to article

Thermodynaimic Study Of Nucleic Acids Recognition By Aminoglycosides , Hongjuan Xi Dec 2007

Thermodynaimic Study Of Nucleic Acids Recognition By Aminoglycosides , Hongjuan Xi

All Dissertations

ABSTRACT


Since the origin of first aminoglycosides antibiotics, streptomycin, isolated by Selman Waksman about 60 years ago, a number of aminoglycosides antibiotics were discovered to treat different infections. Neomycin class aminoglycosides were found to originally target the A site 16S rRNA in the 30S subunit of the ribosome within the Gram-negative bacteria. In addition to its antibacterial effect, aminoglycosides were also found to binding to various other viral RNA structures such as TAR and RRE of HIV, Group I introns and hammerhead ribozyme, implying its potential to be used as antiviral reagent.

Furthermore, previous studies in our laboratory discovered a …

Go to article

Constructed Wetlands For The Landscape Nursery Industry: Nutrient Assimilation And Removal, Sarah White Dec 2007

Constructed Wetlands For The Landscape Nursery Industry: Nutrient Assimilation And Removal, Sarah White

All Dissertations

Runoff from nursery operations is considered a potential non-point source contamination. Water quality and quantity are quickly becoming important factors that drive management practices at these facilities. Constructed wetland systems (CWS) are a management tool that can be used by nursery operations to improve water quality both for recycling within nursery production areas and for eventual release from nursery production areas into surrounding surface waters. The overall goal of this research was to optimize nutrient removal efficiencies in CWS. To accomplish this goal, I characterized the following: (1) the P sorption and desorption capacity of several substrates; (2) the effect …

Go to article

Water Quality Dynamics Of Lake James In The Catawba River Basin Of North Carolina, Susan Stokes Dec 2007

Water Quality Dynamics Of Lake James In The Catawba River Basin Of North Carolina, Susan Stokes

All Dissertations

Lake James is the uppermost hydropower reservoir in the Catawba River drainage in North Carolina. The Lake James Assessment (LJA) was a descriptive study initiated between Clemson University and Duke Energy Corporation to explore the physical, chemical and biological dynamics of this oligotrophic reservoir from spring 1997 through fall 1999 (Schindler 1997). The goals of this study were to ascertain the primary drivers for the chemical dynamics of Lake James, to assess the quantities of constituents entering and leaving the reservoir, where these chemicals were incorporated within the reservoir basins, and to evaluate the efficacy of the LJA chemical budget …

Go to article

Issues In Model Selection, Minimax Estimation, And Censored Data Analysis, Meng Zhao Dec 2007

Issues In Model Selection, Minimax Estimation, And Censored Data Analysis, Meng Zhao

All Dissertations

In this dissertation, we address several research problems in statistical inference. We obtain results in the following four directions: linear model selection, minimax estimation of linear functionals, Bayes type estimators for the survival functions based on right censored data, and estimation of survival functions based on doubly censored data.

Go to article

Diversity And Abundance Of Ants At Forest Edges , Eric Paysen Dec 2007

Diversity And Abundance Of Ants At Forest Edges , Eric Paysen

All Dissertations

Fragmented habitats are a common result of human activities that involve the clearing of native vegetation for various land uses. Habitat fragmentation has two primary and inseparable components: habitat loss and insularization. Landscape-level connectivity in fragmented habitats is diminished for many species, and edge characteristics become more important as the edge-to-interior ratio increases. The study of the effects of edges on biodiversity has compelled ecologists to study them for over a century and has influenced the design and management of natural preserves. Invasion of habitats by non-native species is a phenomenon that coincides with the increased human activity typical of …

Go to article

Influence Of Mercury-Dissolved Organic Matter (Dom) Complexation On Toxicity In Natural Waters, Christina Mcnaughton Dec 2007

Influence Of Mercury-Dissolved Organic Matter (Dom) Complexation On Toxicity In Natural Waters, Christina Mcnaughton

All Dissertations

Global industrialization, coupled with a large biogeochemical cycle that moves mercury through the environment, has resulted in higher mercury concentrations being detected in many environmental compartments. Although the presence of mercury in each compartment has the potential to elicit toxicity, mercury found in natural waters provides the greatest risk, due to the various reactions it can undergo, resulting in a plethora of different species.
Due to the fact that mercury contamination in aquatic systems has the potential to bioaccumulate and biomagnify up the food chain and cause toxicity, understanding the behavior of mercury in these systems is imperative in the …

Go to article

Identification Of The Possible Defect States In Poly(3-Hexylthiophene) Thin Films, D.-Q. Feng, A. N. Caruso, Yaroslav B. Losovyj, D. L. Schulz, Peter A. Dowben Dec 2007

Identification Of The Possible Defect States In Poly(3-Hexylthiophene) Thin Films, D.-Q. Feng, A. N. Caruso, Yaroslav B. Losovyj, D. L. Schulz, Peter A. Dowben

Peter Dowben Publications

The possible origins of a low density of defect states within the highest occupied molecular orbital to lowest unoccupied molecular orbital gap are suggested for regioregular poly(3- hexylthiophene). A number of chemical defects, impurities, and structural defects could contribute to features in photoemission for regioregular poly(3-hexylthiophene), observed within the highest occupied molecular orbital to lowest unoccupied molecular orbital gap of regioregular poly(3-hexylthiophene).

Go to article

Spitzer Irs Observations Of Seyfert 1.8 And 1.9 Galaxies: A Comparison With Seyfert 1 And Seyfert 2, R. P. Deo, D. M. Crenshaw, S. B. Kraemer, M. Dietrich, Moshe Elitzur, H. Teplitz, T. J. Turner Dec 2007

Spitzer Irs Observations Of Seyfert 1.8 And 1.9 Galaxies: A Comparison With Seyfert 1 And Seyfert 2, R. P. Deo, D. M. Crenshaw, S. B. Kraemer, M. Dietrich, Moshe Elitzur, H. Teplitz, T. J. Turner

Physics and Astronomy Faculty Publications

We present Spitzer mid-infrared spectra of 12 Seyfert 1.8 and 1.9 galaxies over the 5-38 μm region. We compare the spectral characteristics of this sample to those of 58 Seyfert 1 and 2 galaxies from the Spitzer archives. An analysis of the spectral shapes, the silicate 10 μm feature and the emission-line fluxes have enabled us to characterize the mid-IR properties of Seyfert 1.8/1.9s. We find that the EWs of the 10 μm silicate feature are generally weak in all Seyfert galaxies, as previously reported by several studies. The few Seyfert galaxies in this sample that show …

Go to article

Structure Formation Inside Triaxial Dark Matter Halos: Galactic Disks, Bulges, And Bars, Clayton Heller, Isaac Shlosman, Evangelie Athanassoula Dec 2007

Structure Formation Inside Triaxial Dark Matter Halos: Galactic Disks, Bulges, And Bars, Clayton Heller, Isaac Shlosman, Evangelie Athanassoula

Department of Physics and Astronomy Faculty Publications

We investigate formation and evolution of galactic disks immersed in assembling live DM halos. Models have been evolved from cosmological initial conditions and represent the collapse of an isolated density perturbation. The baryons include gas participating in star formation (SF) and stars with the energy feedback onto the ISM. We find that (1) the triaxial halo figure tumbling is insignificant and the angular momentum (J) is channeled into the internal circulation, while the baryonic collapse is stopped by the centrifugal barrier; (2) density response of the (disk) baryons is out of phase with DM, thus washing out the …

Go to article

Measurement Of (Anti)Deuteron And (Anti)Proton Production In Dis At Hera, S. Chekanov, M. Derrick, S. Magill, B. Musgrave, D. Nicholass, J. Repond, R. Yoshida, Margarita C. K. Mattingly, M. Jechow, N. Pavel, A. G. Yagües Molina, S. Antonelli, P. Antonioli, G. Bari, M. Basile, L. Bellagamba, M. Bindi, D. Boscherini, A. Bruni, G. Bruni, L. Cifarelli, F. Cindolo, A. Contin, M. Corradi, S. De Pasquale, G. Iacobucci, A. Margotti, R. Nania, A. Polini, G. Sartorelli, A. Zichichi Dec 2007

Measurement Of (Anti)Deuteron And (Anti)Proton Production In Dis At Hera, S. Chekanov, M. Derrick, S. Magill, B. Musgrave, D. Nicholass, J. Repond, R. Yoshida, Margarita C. K. Mattingly, M. Jechow, N. Pavel, A. G. Yagües Molina, S. Antonelli, P. Antonioli, G. Bari, M. Basile, L. Bellagamba, M. Bindi, D. Boscherini, A. Bruni, G. Bruni, L. Cifarelli, F. Cindolo, A. Contin, M. Corradi, S. De Pasquale, G. Iacobucci, A. Margotti, R. Nania, A. Polini, G. Sartorelli, A. Zichichi

Faculty Publications

The first observation of (anti)deuterons in deep inelastic scattering at HERA has been made with the ZEUS detector at a centre-of-mass energy of 300-318 GeV using an integrated luminosity of 120 pb-1. The measurement was performed in the central rapidity region for transverse momentum per unit of mass in the range 0.3 < pT / M < 0.7. The particle rates have been extracted and interpreted in terms of the coalescence model. The (anti)deuteron production yield is smaller than the (anti)proton yield by approximately three orders of magnitude, consistent with the world measurements. © 2007 Elsevier B.V. All rights reserved.

Go to article

Studies Of The Stability And Potential Applications Of Pyrrolidinofullerenes And Other Fullerene Derivatives, Olena Lukoyanova Dec 2007

Studies Of The Stability And Potential Applications Of Pyrrolidinofullerenes And Other Fullerene Derivatives, Olena Lukoyanova

All Dissertations

Over the last decade, the variety of chemically modified fullerenes and their potential applications has increased significantly. Among fullerene derivatives, pyrrolidinofullerenes are one of the most widely synthesized types since they can be easily and efficiently obtained via simple reactions from both empty and endohedral fullerenes. Although fullerenes in general and pyrrolidinofullerenes in particular have been considered for numerous applications in electronic and optoelectronic devices, photovoltaics, medicinal chemistry, etc., their potential application in the evolving field of molecular electronics has not been extensively explored. The envisioned role of the fullerenes usually involves storage or transport of electrons. Therefore, studies of …

Go to article

Multijet Production At Low XBj In Deep Inelastic Scattering At Hera, S. Chekanov, M. Derrick, S. Magill, B. Musgrave, D. Nicholass, J. Repond, R. Yoshida, Margarita C. K. Mattingly, M. Jechow, N. Pavel, A. G. Yagües Molina, S. Antonelli, P. Antonioli, G. Bari, M. Basile, L. Bellagamba, M. Bindi, D. Boscherini, A. Bruni, G. Bruni, L. Cifarelli, F. Cindolo, A. Contin, M. Corradi, S. De Pasquale, G. Iacobucci, A. Margotti, R. Nania, A. Polini, G. Sartorelli, A. Zichichi Dec 2007

Multijet Production At Low XBj In Deep Inelastic Scattering At Hera, S. Chekanov, M. Derrick, S. Magill, B. Musgrave, D. Nicholass, J. Repond, R. Yoshida, Margarita C. K. Mattingly, M. Jechow, N. Pavel, A. G. Yagües Molina, S. Antonelli, P. Antonioli, G. Bari, M. Basile, L. Bellagamba, M. Bindi, D. Boscherini, A. Bruni, G. Bruni, L. Cifarelli, F. Cindolo, A. Contin, M. Corradi, S. De Pasquale, G. Iacobucci, A. Margotti, R. Nania, A. Polini, G. Sartorelli, A. Zichichi

Faculty Publications

Inclusive dijet and trijet production in deep inelastic ep scattering has been measured for 10 < Q2 < 100 GeV2 and low Bjorken x, 10-4 < xBj < 10-2. The data were taken at the HERA ep collider with centre-of-mass energy sqrt(s) = 318 GeV using the ZEUS detector and correspond to an integrated luminosity of 82 pb-1. Jets were identified in the hadronic centre-of-mass (HCM) frame using the kT cluster algorithm in the longitudinally invariant inclusive mode. Measurements of dijet and trijet differential cross sections are presented as functions of Q2, xBj, jet transverse energy, and jet pseudorapidity. As a further examination of low-xBj dynamics, multi-differential cross sections as functions of the jet correlations in transverse momenta, azimuthal angles, and pseudorapidity are also presented. Calculations at O (αs3) generally describe the trijet data well and improve the description of the dijet data compared to the calculation at O (αs2). © 2007 Elsevier B.V. All rights reserved.

Go to article

Learning Languages From Positive Data And A Limited Number Of Short Counterexamples, Sanjay Jain, Efim Kinber Dec 2007

Learning Languages From Positive Data And A Limited Number Of Short Counterexamples, Sanjay Jain, Efim Kinber

School of Computer Science & Engineering Faculty Publications

We consider two variants of a model for learning languages in the limit from positive data and a limited number of short negative counterexamples (counterexamples are considered to be short if they are smaller than the largest element of input seen so far). Negative counterexamples to a conjecture are examples which belong to the conjectured language but do not belong to the input language. Within this framework, we explore how/when learners using n short (arbitrary) negative counterexamples can be simulated (or simulate) using least short counterexamples or just ‘no’ answers from a teacher. We also study how a limited number …

Go to article

Solid Phase Crystallization Of Vanadium Dioxide Thin Films And Characterization Through Scanning Electron Microscopy, Felipe Rivera Dec 2007

Solid Phase Crystallization Of Vanadium Dioxide Thin Films And Characterization Through Scanning Electron Microscopy, Felipe Rivera

Theses and Dissertations

Crystalline films of vanadium dioxide were obtained through thermal annealing of amorphous vanadium dioxide thin films sputtered on silicon dioxide. An annealing process was found that yielded polycrystalline vanadium dioxide thin films, semi-continuous thin films, and films of isolated single-crystal particles. Orientation Imaging Microscopy (OIM) was used to characterize and study the phase and the orientation of the vanadium dioxide crystals obtained, as well as to diferentiate them from other vanadium oxide stoichiometries that may have formed during the annealing process. There was no evidence of any other vanadium oxides present in the prepared samples. Indexing of the crystals for …

Go to article

Charge Effects In Bilayer Electric Transport, Christopher Czech Dec 2007

Charge Effects In Bilayer Electric Transport, Christopher Czech

All Theses

The mathematical isomorphism between the layer index in a bilayer system and the spin index in a spin-polarized system is used to draw an analogy between phenomena that occur in the two systems as a result of the electron-electron (e-e) interaction. First, the classical case of the Coulomb drag, a phenomenon resulting from momentum transfer through e-e collisions, is reviewed for both bilayer systems and spin-polarized systems. Then, the spin-backflow phenomenon, a result of the interaction-induced changes in the local quasiparticle energy that affects the charge transport in spin-polarized systems is presented. Finally, the iso-spin correlation is exploited to establish …

Go to article

Characterization Of Metalferroelectric-Insulator-Semiconductor Structures Based On Ferroelectric Langmuir-Blodgett Polyvinylidene Fluoride Copolymer Films For Nondestructive Random Access Memory Applications, Timothy J. Reece Dec 2007

Characterization Of Metalferroelectric-Insulator-Semiconductor Structures Based On Ferroelectric Langmuir-Blodgett Polyvinylidene Fluoride Copolymer Films For Nondestructive Random Access Memory Applications, Timothy J. Reece

Department of Physics and Astronomy: Dissertations, Theses, and Student Research

Ferroelectric field effect transistors (FeFETs) have attracted much attention recently because of their ability to combine high speed, low power consumption, and fast nondestructive readout with the potential for high density nonvolatile memory. The polarization of the ferroelectric is used to switch the channel at the silicon surface between states of high and low conductance.

Among the ferroelectric thin films used in FET devices; the ferroelectric copolymer of Polyvinylidene fluoride, PVDF (C2H2F2), with trifluoroethylene, TrFE (C2HF3), has distinct advantages, including low dielectric constant, low processing temperature, low cost and compatibility …

Go to article

How To Hunt A Wild Neutrino, Janet Conrad Dec 2007

How To Hunt A Wild Neutrino, Janet Conrad

IMSA Great Minds Program ®

Of all of the particles which make up matter, the neutrino is the most mysterious. Remnants of the big bang, neutrinos are everywhere -- up in your attic, out in the cornfields, deep in the farthest galaxies. Catching them has always been a problem. But recently we have discovered one of their tricks. They can change their spots -- from one type into another! This talk will discuss neutrinos, how to catch them, and in the context of the research at Fermilab.

Go to article

Geochemical Reconstruction Of Late Holocene Drainage And Mixing In Kluane Lake, Yukon Territory, Janice Brahney, John J. Clague, Brian Menounos, Thomas W. D. Edwards Dec 2007

Geochemical Reconstruction Of Late Holocene Drainage And Mixing In Kluane Lake, Yukon Territory, Janice Brahney, John J. Clague, Brian Menounos, Thomas W. D. Edwards

Watershed Sciences Faculty Publications

The level of Kluane Lake in southwest Yukon Territory, Canada, has fluctuated tens of metres during the late Holocene. Contributions of sediment from different watersheds in the basin over the past 5,000 years were inferred from the elemental geochemistry of Kluane Lake sediment cores. Elements associated with organic material and oxyhydroxides were used to reconstruct redox fluctuations in the hypolimnion of the lake. The data reveal complex relationships between climate and river discharge during the late Holocene. A period of influx of Duke River sediment coincides with a relatively warm climate around 1,300 years BP. Discharge of Slims River into …

Go to article

Small-Scale X-Ray Variability In The Cassiopeia A Supernova Remnant, Daniel J. Patnaude, Robert A. Fesen Dec 2007

Small-Scale X-Ray Variability In The Cassiopeia A Supernova Remnant, Daniel J. Patnaude, Robert A. Fesen

Dartmouth Scholarship

A comparison of X-ray observations of the Cassiopeia A supernova remnant taken in 2000, 2002, and 2004 with the Chandra ACIS-S3 reveals the presence of several small-scale features (≤10'') that exhibit significant intensity changes over a 4 yr time frame. Here we report on the variability of six features, four of which show count rate increases from ~10% to over 90%, and two of which show decreases of ~30%-40%. While extracted 1-4.5 keV X-ray spectra do not reveal gross changes in emission-line strengths, spectral fits using nonequilibrium-ionization, metal-rich plasma models indicate increased or decreased electron temperatures for features showing increasing …

Go to article

First Prev Next Last