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2009

Clemson University

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Full-Text Articles in Physical Sciences and Mathematics

Polymeric Carbon Nanocomposites - Preparation, Characterization, And Properties, Lucia Veca Dec 2009

Polymeric Carbon Nanocomposites - Preparation, Characterization, And Properties, Lucia Veca

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Excellent thermal properties of carbon nanomaterials such as carbon nanotubes and newly discovered graphene make them the filler of choice for the development of thermal management materials. Graphene has been viewed as “ unrolled single-walled carbon nanotube and as a wonder material with many superlatives to its name ” thus there is an excessive interest in developing new synthetic routes towards large scale production of high quality graphene nanosheets.
In this dissertation, we report different methods that could further exfoliate the commercially available expanded graphite to nanometer sized carbon structures, “carbon nanosheets ”, for their use in highly thermal conductive …

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Decoding Of Multipoint Algebraic Geometry Codes Via Lists, Nathan Drake Dec 2009

Decoding Of Multipoint Algebraic Geometry Codes Via Lists, Nathan Drake

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Algebraic geometry codes have been studied greatly since their introduction by Goppa . Early study had focused on algebraic geometry codes CL(D;G) where G was taken to be a multiple of a single point. However, it has been shown that if we allow G to be supported by more points, then the associated code may have better parameters. We call such a code a multipoint code and if G is supported by m points, then we call it an m-point code. In this dissertation, we wish to develop a decoding algorithm for multipoint codes. We show how we can embed …

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Synthesis, Modification Of Mesoporous Carbons And Their Application In Polymer Electrolyte Membrane Fuel Cells, Bing Liu Dec 2009

Synthesis, Modification Of Mesoporous Carbons And Their Application In Polymer Electrolyte Membrane Fuel Cells, Bing Liu

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Mesoporous carbon materials of carbon xerogel (CX) and silica-templated carbon (MC) were synthesized and explored as catalyst supports alternative to the most-commonly-used carbon black (CB) support, for polymer-electrolyte-membrane fuel cell (PEMFC) application. Pt catalyst was loaded on these carbons and electrodes were fabricated from them. These Pt-loaded carbon supports were characterized with XRD, TEM, ex-situ and in-situ cyclic voltammetry, etc. The fabricated electrodes were evaluated in single-cell testing in comparison with commercial CB-supported Pt catalyst fabricated electrodes. The experimental results showed that CX-supported Pt catalyst had close or better performance than that of CB-supported Pt, possibly due to CX's 3-D …

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Metal Oxide And Mercuric Sulfide Nanoparticles Synthesis And Characterization, Xin Xu Dec 2009

Metal Oxide And Mercuric Sulfide Nanoparticles Synthesis And Characterization, Xin Xu

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Increasing applications of nanoparticles (NPs), such as metal oxide and mercuric sulfide NPs, lead to heightened environmental concern. Challenges to the study of natural and engineered NPs include the physical and chemical characterizations.
Commercially available and laboratory-synthesized metal based NPs, iron oxide (Fe2O3), copper oxide (CuO), titanium dioxide (TiO2), zinc oxide (ZnO) and mercuric sulfide (HgS) were studied by comprehensive characterizations methods. The general synthesis process was modified sol-gel method. The size and morphology of NPs could be influenced by temperature, sonication, calcination, precursor concentration, pH and types of reaction media. In the synthesis of nZnO in ethanol, the essential …

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Atom Scattering From Metals, William Hayes Dec 2009

Atom Scattering From Metals, William Hayes

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In the initial portion of this dissertation studies of Ar
scattering from Ru(0001) at thermal and hyperthermal energies are
compared to calculations with classical scattering theory. These
data exhibited a number of characteristics that are unusual in
comparison to other systems for which atomic beam experiments have
been carried out under similar conditions. The measured energy
losses were unusually small. Some of the angular distributions
exhibited an anomalous shoulder feature in addition to a broad
peak near the specular direction and quantum mechanical
diffraction was observed under conditions for which it was not
expected. Many of the unusual features observed …

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Visuohaptic Simulation Of A Borescope For Aircraft Engine Inspection, Deepak Vembar Dec 2009

Visuohaptic Simulation Of A Borescope For Aircraft Engine Inspection, Deepak Vembar

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Consisting of a long, fiber optic probe containing a small CCD camera controlled by hand-held articulation interface, a video borescope is used for remote visual inspection of hard to reach components in an aircraft. The knowledge and psychomotor skills, specifically the hand-eye coordination, required for effective inspection are hard to acquire through limited exposure to the borescope in aviation maintenance schools. Inexperienced aircraft maintenance technicians gain proficiency through repeated hands-on learning in the workplace along a steep learning curve while transitioning from the classroom to the workforce.
Using an iterative process combined with focused user evaluations, this dissertation details the …

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Synthesis And Development Of Novel Fullerene-Based Structures For Photovoltaics, Electronic Applications And Mri Contrast Agents, Manuel Chaur Dec 2009

Synthesis And Development Of Novel Fullerene-Based Structures For Photovoltaics, Electronic Applications And Mri Contrast Agents, Manuel Chaur

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Metallic nitride endohedral metallofullerenes (EMFs) are one of the most interesting types of metallofullerenes due to their high yields and interesting electronic properties. The synthesis of these compounds allows the encapsulation of different metals inside fullerenes making it possible to combine the properties of the metal with those of the fullerene. Their interesting electrochemical and optical features make them potential candidates for several applications such as molecular electronics, biomedical imaging, non-linear optical devices, and magnetic resonance imaging (MRI) agents. This thesis reports the synthesis of novel metallic nitride EMFs based on Gd, Nd, Pr, Ce and La. These families of …

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Examining The Dynamics Of Managing Information Systems Development Projects: A Control Loss Perspective, Ravi Narayanaswamy Dec 2009

Examining The Dynamics Of Managing Information Systems Development Projects: A Control Loss Perspective, Ravi Narayanaswamy

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The failure rate of information systems development (ISD) projects continues to pose a big challenge for organizations. The success rate of ISD projects is less then forty percent. Factors such as disagreements and miscommunications among project manager and team members, poor monitoring and intermediary problems contribute to project failure.
Agency theory and leader member exchange (LMX) theories offer potential explanations for project failure. In particular, three monitoring strategies - control strategy, decision rights, and influence tactics were found to be effective in promoting project success. LMX theorists suggest that achieving congruence between the manager and subordinate regarding each other actions …

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Characterization Of Escherichia Coli Related To Construction Site Sediment Basins, Calvin Sawyer Dec 2009

Characterization Of Escherichia Coli Related To Construction Site Sediment Basins, Calvin Sawyer

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Large construction sites can have significant temporary and permanent impacts on the physical landscape. Excess sediment is frequently deposited into nearby surface waters, altering benthic habitat, reducing water clarity and transporting other pollutants such as enteric bacteria. To capture eroded soil and attenuate storm discharge peaks, many permitted construction projects larger than 10 acres in South Carolina require the installation of a sediment basin. Sediment-laden runoff is routed to a newly excavated impoundment, where larger particles settle out of suspension. Thus an entirely new hydrologic feature designed to concentrate eroded sediment and water is introduced into the landscape.
Eight construction …

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Branchings And Time Evolution Of Reaction Networks, Changyuan Wang Dec 2009

Branchings And Time Evolution Of Reaction Networks, Changyuan Wang

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In this thesis I analyze flows in reaction networks in terms of branchings
in a digraph. If the coupled differential equations governing the rate
of change of probabilities X of a state or species are finite-differenced in time, a matrix equation (I + Adt)X(t+dt) = X(t) results, where X(t) is a vector giving the probabilities at time t and X(t+dt) is a vector giving the probabilities at time t + dt. I demonstrate that the matrix (I + Adt) may be written as the product of an incidence matrix and a weight matrix for a directed graph (digraph) representing the …

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Synthesis And Characterization Of Metallic, Core-Shell And Composite Nanoparticles, Amar Kumbhar Dec 2009

Synthesis And Characterization Of Metallic, Core-Shell And Composite Nanoparticles, Amar Kumbhar

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ABSTRACT
Silver nanoparticles exhibit size, shape and the surrounding dielectric medium dependent optical properties (scattering and absorption) in the visible spectral region. These optical properties can be explained in terms of the collective oscillation of the 'free conduction band electrons' or 'surface plasmons' induced by an external electromagnetic field. Dipole and Quadrupole Plasmon resonances have been observed for silver particles less than 100nm in diameter prepared using various synthetic techniques. However higher order resonances have been elusive due to lack of experimental techniques to prepare colloidal solutions of large silver nanoparticles in the size range above 100nm. Controlled hydrogen reduction …

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Development Of A Fluorescent Probe For Determination Of Water Transport In Subcellular Organelles, Adriana Chaurra-Arboleda Dec 2009

Development Of A Fluorescent Probe For Determination Of Water Transport In Subcellular Organelles, Adriana Chaurra-Arboleda

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Water transport has been widely studied in a variety of cells and isolated membranes. However, the intrinsic complexity related with the study of intracellular processes has delayed the development of an analytical technique for the study of water transport in subcellular compartments of living cells. This study represents the development and application of a ratiometric fluorescent probe to study water transport in endocytic organelles of intact living cells. The probe is based on the use of a D2O-sensitive fluorophore, Lucifer yellow dextran (LY-dex), together with a D2O-insensitive fluorophore, Alexa fluor 546 dextran (AF546-dex), used as an …

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A Study Of The Mesosphere-Lower Thermosphere: Noctilucent Cloud Observations And Rocket Borne Density Measurements, Shelton Simmons Dec 2009

A Study Of The Mesosphere-Lower Thermosphere: Noctilucent Cloud Observations And Rocket Borne Density Measurements, Shelton Simmons

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Herein, a study of a noctilucent cloud, NLC, display from 17 July 2007 is analyzed. A photogrammetric analysis was applied to time lapsed photographs taken from two observation sites, RŸgen and KŸhlungsborn, Germany. Both Kelvin-Helmholtz instabilities and internal gravity waves were identified during the NLC display based on the typical characteristics of such waves in the mesopause region. With the two observation sites, the location of details can be identified with an accuracy of ±0.125¡ longitude and ±0.5¡ latitude. A gravity wave with a wavelength of 50km and Kelvin-Helmholtz instability or gravity wave of wavelength 16.5km were observed. The 16.5km …

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Risk Assessment Of Bird Aircraft Strike Hazard For Grassland Birds At The Mcentire Air National Guard Station, Eastover, South Carolina, Marla Hamilton Dec 2009

Risk Assessment Of Bird Aircraft Strike Hazard For Grassland Birds At The Mcentire Air National Guard Station, Eastover, South Carolina, Marla Hamilton

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ABSTRACT
There are strict regulations surrounding vegetation management at military airfields for the purpose of reducing Bird Aircraft Strike Hazards (B.A.S.H.). At military installations vegetation heights are set between 17 to 38 cm to discourage the use of animal species such as flocking birds, soarers (e.g. raptors), large wading birds (e.g. herons), and waterfowl that create hazards to flying aircraft. Within designated clear zones, managers have typically promoted the growth of non - non-native grasses without much consideration for how these plantings might impact B.A.S.H. potential, bird occupancy, or avian conservation. Grasslands and grassland associated avifauna are among the 'highest …

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Semantic Search, Anup Sawant Dec 2009

Semantic Search, Anup Sawant

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The thesis describes a Semantic approach towards web search through a stand-alone Java application. An Ontology Web Language(OWL) model is used to build a knowledge database related to different types of Organisms. The goal is to guide the Google web search engine using this OWL model. In the rst approach towards Semantic web search, an inference engine called CLIPS is used and in the second aproach, the Protege-OWL API is used. The thesis goes in detail about the design,
working and comparison of these two approaches. The thesis also deals with design approach for enhancement of the OWL model, once …

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Roost Selection By Rafinesque's Big-Eared Bats, Corynorhinus Rafinesquii, In Congaree National Park - A Multiscale Approach, Jessica Lucas Dec 2009

Roost Selection By Rafinesque's Big-Eared Bats, Corynorhinus Rafinesquii, In Congaree National Park - A Multiscale Approach, Jessica Lucas

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Little is known about natural roost selection of Rafinesque's big-eared bats, Corynorhinus rafinesquii , throughout their range. The objectives of this study were to determine roost use and selection of big-eared bats in the Upper Coastal Plain of South Carolina at multiple spatial scales and test whether roost use and selection differed between maternity colonies and solitary individuals. The study was conducted May-August 2006 and 2007 in Congaree National Park which contains extensive areas of old-growth bottomland forest. Roost trees were located via tree searches and radio-telemetry and I used univariate tests and multiple logistic regression to compare tree, stand, …

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Analysis Of Mercury And Lead In Birds Of Prey From Gold-Mining Areas Of The Peruvian Amazon, Peggy Shrum Dec 2009

Analysis Of Mercury And Lead In Birds Of Prey From Gold-Mining Areas Of The Peruvian Amazon, Peggy Shrum

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This study was conducted to determine levels of lead and mercury in the raptors of the South-eastern Peruvian Amazon. The study took place within the Los Amigos Conservation Concession in Madre de Dios, Peru. Eighty-six raptors from among sixteen species were captured with Bal-Chatri traps. From each individual, feather samples were obtained for mercury analysis and blood was taken for lead analysis. Each raptor was then released without incident or injury.
Mercury amalgamation for gold extraction is widely used by small-scale, transient mining operations, which are numerous along the rivers and creeks in the tropical forests and other locations in …

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Uptake Of Gold Nanoparticles In An Algae - Daphnid Food Chain, Matthew Osborne-Koch Dec 2009

Uptake Of Gold Nanoparticles In An Algae - Daphnid Food Chain, Matthew Osborne-Koch

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Nanoparticle entry into the environment can result in deleterious effects to exposed organisms, disruption of ecological processes, and accumulation within the wood web. Gold nanoparticles (AuNPs), which are classified as zero-valent metals, are of significant interest due to their use in a variety of applications including electrical, biomedical, catalytic, magnetic, and optical technology. The wide range of uses for AuNPs can be attributed to a combination of the unique physical properties of the element gold (i.e. density, conductivity, stability, etc.) and the diversity of sizes, shapes, and surface compositions that can be achieved through manipulation of AuNP synthesis. While previous …

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Light Beaming From A Single Subwavelength Metal Slit, Pengyu Chen Dec 2009

Light Beaming From A Single Subwavelength Metal Slit, Pengyu Chen

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In this thesis, light transmission through a single sub-wavelength slit in a silver thin film with periodic gratings at the exit side of the slit has been studied in both the visible and mid-infrared wavelength ranges.
In the visible wavelength range, we first investigate the enhancement of plasmonic light beaming efficiency by near field resonance in a subwavelength metallic slit-groove beaming structure. We show that by varying the film thickness and the separation distance of the beaming grating, the intensity of the near field can be greatly enhanced by resonance, which leads to the increase of the beaming efficiency. Moreover, …

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The Effects Of Pulsed Exposures Of Suspended Clay On The Survival, Growth, And Reproduction Of Daphnia Magna, Sarah Robinson Dec 2009

The Effects Of Pulsed Exposures Of Suspended Clay On The Survival, Growth, And Reproduction Of Daphnia Magna, Sarah Robinson

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Suspended sediments are a natural component of aquatic ecosystems but anthropogenic activity such as land development can result in significant increases, especially following rain events due to surface erosion. Continuous exposures of suspended clay and silt have been shown to effect growth and reproduction of Cladocera, leading to a decrease in population growth rate. The mechanism of clay toxicity in these filter-feeding organisms is clogging of the gut tract resulting in decreased food uptake and assimilation. When placed in clean water, daphnids can purge clay from their gut and recover. In many surface waters, aquatic organisms experience episodic exposures of …

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An Animation Framework For Improving The Comprehension Of Tinyos Programs, Sravanthi Dandamudi Dec 2009

An Animation Framework For Improving The Comprehension Of Tinyos Programs, Sravanthi Dandamudi

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To meet the increasing demand for monitoring of the physical world, there has been an increase in the development of wireless sensor network applications. The TinyOS platform has emerged as a de facto standard for developing these applications. The platform offers a number of advantages, with its support for concurrency, power-efficient operation, and resource-constrained hardware chief among them. However, the benefits come at a price. Even without the TinyOS platform, the inherent parallel and distributed nature of these applications makes it difficult for developers to reason about program behavior. Further, the TinyOS programming model adopts
asynchronous, split-phase execution semantics. Developers …

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Some New Problems In Changepoint Analysis, Jonathan Woody Dec 2009

Some New Problems In Changepoint Analysis, Jonathan Woody

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Climatological studies have often neglected changepoint effects when modeling
various physical phenomena. Here, changepoints are plausible whenever a station location moves or its instruments are changed. There is frequently meta-data to
perform sound statistical inferences that account for changepoint
information. This dissertation focuses on two such problems in changepoint analysis.
The first problem we investigate involves assessing trends
in daily snow depth series. Here, we introduce a stochastic storage model. The model allows for seasonal features, which permits the
analysis of daily data. Changepoint times are shown to greatly influence estimated trends in one snow depth series and are accounted …

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Field Evaluation Of The Immunocontraceptive Gonacontm In Reducing Eastern Gray Squirrel Fecundity In Urban Areas, Murali Pai Dec 2009

Field Evaluation Of The Immunocontraceptive Gonacontm In Reducing Eastern Gray Squirrel Fecundity In Urban Areas, Murali Pai

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The purpose of this study was to evaluate the immunocontraceptive GonaConTM in reducing fecundity in Eastern gray squirrel (EGS) (Sciurus carolinensis) in urban areas. Using a modified box trap design, 317 EGS were captured during four trapping sessions on a 5.66 ha site on Clemson University's main campus. EGS were handled using a restraint cone and sexed, weighed, ear-tagged and implanted with a microchip at the nape of the neck on all 'original' captures and later identified in subsequent captures as 'recaptures.' Blood samples and morphometric data were obtained on EGS before the immunocontraceptive GonaConTM was administered by …

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An Approach Designed For Reginal Prospective Human Health And Ecological Risk Assessment And Its Application To Mercury Risks From A Coal-Fired Power Plant, Pathratipa Sansayavichai Dec 2009

An Approach Designed For Reginal Prospective Human Health And Ecological Risk Assessment And Its Application To Mercury Risks From A Coal-Fired Power Plant, Pathratipa Sansayavichai

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A large and/or long-term released source of a toxic chemical(s) can cause adverse effects to humans and non–human species inhabiting all over the region. The overall goal of this dissertation was to improve practices in risk assessment concerning a regional risk posed by a prospective source. A generic conceptual framework for performing regional prospective human health and ecological risk assessment was developed. The formulation of a priori considerations was used to identify the possible sources of uncertainties in the prospective risk assessment. Physiologically based pharmacokinetic (PBPK) modeling was utilized to reduce uncertainty in a toxicologically safe dose used in risk …

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Functional Characterization Of Calcium Dependent Protein Kinase 32 From Arabidopsis, Rucha Karve Dec 2009

Functional Characterization Of Calcium Dependent Protein Kinase 32 From Arabidopsis, Rucha Karve

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Calcium-dependent protein kinases (CPKs) are major plant Ca2+ sensors, many of which have roles in plant stress responses. The Arabidopsis genome encodes 34 CPK isoforms. Here we report characterization of AtCPK32 gene function. Analysis of transgenic plants expressing pCPK32-GUS shows that CPK32 is highly expressed in roots, pollen and embryo, as well as leaf hydathodes, and the abscission zone of mature siliques. Real time RT-PCR and promoter expression patterns show that CPK32 is responsive to abiotic and biotic stresses. Plants treated with salt, ABA, osmotic stress (PEG), wounding, and flagellin 22 peptide show up-regulation of CPK32 upon these stress treatments. …

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Observations Of Very High Energy Gamma-Ray Emission From Supernova Remnants With Veritas, Mark Theiling Dec 2009

Observations Of Very High Energy Gamma-Ray Emission From Supernova Remnants With Veritas, Mark Theiling

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The nature and source of cosmic rays has been at the core of particle astrophysics since their discovery almost a century ago. The cosmic ray spectrum is best described by a broken power law, and can be better understood as three distinct parts. Theory holds that cosmic rays up to ∼1015 eV – those below the “knee” or steepening in the spectrum – are produced in the shocks of supernova remnants. Direct detection of cosmic rays produced in supernova remnant shocks is impossible, however, as cosmic rays below ∼1018 eV are deflected by the Galactic magnetic field and cannot be …

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A Cognitive Model For Problem Solving In Computer Science, Jennifer Parham Dec 2009

A Cognitive Model For Problem Solving In Computer Science, Jennifer Parham

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According to industry representatives, computer science education needs to emphasize the processes involved in solving computing problems rather than their solutions. Most of the current assessment tools used by universities and computer science departments analyze student answers to problems rather than investigating the processes involved in solving them. Approaching assessment from this perspective would reveal potential errors leading to incorrect solutions.
This dissertation proposes a model describing how people solve computational problems by storing, retrieving, and manipulating information and knowledge. It describes how metacognition interacts with schemata representing conceptual and procedural knowledge, as well as with the external sources of …

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On The Testing And Estimation Of High-Dimensional Covariance Matrices, Thomas Fisher Dec 2009

On The Testing And Estimation Of High-Dimensional Covariance Matrices, Thomas Fisher

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Many applications of modern science involve a large number of parameters. In
many cases, the number of parameters, p, exceeds the number of observations,
N. Classical multivariate statistics are based on the assumption that the
number of parameters is fixed and the number of observations is large. Many of
the classical techniques perform poorly, or are degenerate, in high-dimensional
situations.
In this work, we discuss and develop statistical methods for inference of
data in which the number of parameters exceeds the number of observations.
Specifically we look at the problems of hypothesis testing regarding and the
estimation of the covariance …

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Exploring Formation And Distribution Of Halonitromethanes In Drinking Waters, Jia Hu Dec 2009

Exploring Formation And Distribution Of Halonitromethanes In Drinking Waters, Jia Hu

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ABSTRACT
Nine halonitromethanes (HNMs) were among the more than fifty unregulated high-priority disinfection by-products (DBPs) that were monitored for and detected in drinking waters in a 2000-2002 nationwide occurrence study funded by the US Environmental Protection Agency (USEPA). The toxicology studies conducted in recent years have shown that HNMs are one of the most cytotoxic and genotoxic classes among the emerging DBPs, with orders of magnitude higher cytotoxicity and genotoxicity than any of the regulated organic DBPs. Furthermore, brominated HNMs were found to be more toxic than their chlorinated analogs, with dibromonitromethane being the most cyto- and genotoxic. Today, our …

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Writing A Supercomputer Proposal For The National Science Foundation's Major Research Instrumentation Solicitation, Amy Apon Oct 2009

Writing A Supercomputer Proposal For The National Science Foundation's Major Research Instrumentation Solicitation, Amy Apon

Presentations

No abstract provided.

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