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2013

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Articles 8431 - 8460 of 11462

Full-Text Articles in Physical Sciences and Mathematics

Metr 323: Physical Meteorology—A Peer Review Of Teaching Project Benchmark Portfolio, Jun Wang Jan 2013

Metr 323: Physical Meteorology—A Peer Review Of Teaching Project Benchmark Portfolio, Jun Wang

UNL Faculty Course Portfolios

Hands-on out-door activities are added into a course that is designed to teach students atmospheric physics ranging form solar light transfer to cloud and precipitation formation in the atmosphere. Statistical analysis and anonymous survey are conducted to benchmark the improvement in students' learning. Results show that these hands-on activities increase the student's interest and understanding in the course materials, and also improve the overall students' satisfaction for the course.

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Towards An Early Software Estimation Using Log-Linear Regression And A Multilayer Perceptron Model, Ali Bou Nassif, Nfa-Estimation, Luiz Fernando Capretz Jan 2013

Towards An Early Software Estimation Using Log-Linear Regression And A Multilayer Perceptron Model, Ali Bou Nassif, Nfa-Estimation, Luiz Fernando Capretz

Electrical and Computer Engineering Publications

Software estimation is a tedious and daunting task in project management and software development. Software estimators are notorious in predicting software effort and they have been struggling in the past decades to provide new models to enhance software estimation. The most critical and crucial part of software estimation is when estimation is required in the early stages of the software life cycle where the problem to be solved has not yet been completely revealed. This paper presents a novel log-linear regression model based on the use case point model (UCP) to calculate the software effort based on use case diagrams. …

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Contellation: Taurus, Gabriel Chaille Jan 2013

Contellation: Taurus, Gabriel Chaille

Natural Sciences Student Research Presentations

Using the constellation Taurus, the purpose of this project was to gain insight on how information is gathered about stars and what purpose that information serves.

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Multi-Dimentional Use Of Mri For Optimizing Reactions In Industries, Vyanti Sagram Jan 2013

Multi-Dimentional Use Of Mri For Optimizing Reactions In Industries, Vyanti Sagram

Natural Sciences Student Research Presentations

MRI Imaging has been used for many years and in a wide variety of industries. Recently. another application of MRI has been discovered by chemists. This research in MRI, a major step toward bridging the gap between laboratory studies and industrial catalysts, could help improve the design and environmental impact of catalytic reactors. This is a project for the Natural Sciences Poster Session at Parkland College.

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Developing A Group Decision Support System (Gdss) For Decision Making Under Uncertainty, Soroush Mokhtari Jan 2013

Developing A Group Decision Support System (Gdss) For Decision Making Under Uncertainty, Soroush Mokhtari

Electronic Theses and Dissertations

Multi-Criteria Decision Making (MCDM) problems are often associated with tradeoffs between performances of the available alternative solutions under decision making criteria. These problems become more complex when performances are associated with uncertainty. This study proposes a stochastic MCDM procedure that can handle uncertainty in MCDM problems. The proposed method coverts a stochastic MCDM problem into many deterministic ones through a Monte-Carlo (MC) selection. Each deterministic problem is then solved using a range of MCDM methods and the ranking order of the alternatives is established for each deterministic MCDM. The final ranking of the alternatives can be determined based on winning …

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Metrology Of Volume Chirped Bragg Gratings Recorded In Photo-Thermo-Refractive Glass For Ultrashort Pulse Stretching And Compressing, Christopher Lantigua Jan 2013

Metrology Of Volume Chirped Bragg Gratings Recorded In Photo-Thermo-Refractive Glass For Ultrashort Pulse Stretching And Compressing, Christopher Lantigua

Electronic Theses and Dissertations

Chirped Bragg gratings (CBGs) recorded in photo-thermo-refractive (PTR) glass provide a very efficient and robust way to stretch and compress ultra-short laser pulses. These gratings offer the ability to stretch pulses from hundreds of femtoseconds, to the order of 1 ns and then recompress them. However, in order to achieve pulse stretching of this magnitude, 100 mm thick CBGs are needed. Using these CBGs to both stretch, and re-compress the pulse thus requires propagation through 200 mm of optical glass. This therefore demands perfect control of the glass homogeneity, as well as the holographic recording process of the CBG. In …

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Extensions Of S-Spaces, Bernd Losert Jan 2013

Extensions Of S-Spaces, Bernd Losert

Electronic Theses and Dissertations

Given a convergence space X, a continuous action of a convergence semigroup S on X and a compactification Y of X, under what conditions on X and the action on X is it possible to extend the action to a continuous action on Y . Similarly, given a Cauchy space X, a Cauchy continuous action of a Cauchy semigroup S on X and a completion Y of X, under what conditions on X and the action on X is it possible to extend the action to a Cauchy continuous action on Y . We answer the first question for some …

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Trace Contaminant Control: An In-Depth Study Of A Silica-Titania Composite For Photocatalytic Remediation Of Closed-Environment Habitat Air, Janelle Coutts Jan 2013

Trace Contaminant Control: An In-Depth Study Of A Silica-Titania Composite For Photocatalytic Remediation Of Closed-Environment Habitat Air, Janelle Coutts

Electronic Theses and Dissertations

This collection of studies focuses on a PCO system for the oxidation of a model compound, ethanol, using an adsorption-enhanced silica-Ti02 composite (STC) as the photocatalyst; studies are aimed at addressing the optimization of various parameters including light source, humidity, temperature, and possible poisoning events for use as part of a system for gaseous trace-contaminant control system in closed-environment habitats. The first goal focused on distinguishing the effect of photon flux (i.e., photons per unit time reaching a surface) from that ofphoton energy (i.e., wavelength) of a photon source on the PCO of ethanol. Experiments were conducted in a bench-scale …

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Investigation Of A Novel Magnesium And Acidified Ethanol System For The Degradation Of Persistent Organic Pollutants, Phillip Maloney Jan 2013

Investigation Of A Novel Magnesium And Acidified Ethanol System For The Degradation Of Persistent Organic Pollutants, Phillip Maloney

Electronic Theses and Dissertations

For centuries chemists have sought to improve humankind’s quality of life and address many of society’s most pressing needs through the development of chemical processes and synthesis of new compounds, often with phenomenal results. Unfortunately, there also are many examples where these chemicals have had unintended, detrimental consequences that are not apparent until years or decades after their initial use. There are numerous halogenated molecules in this category that are globally dispersed, resistant to natural degradation processes, bioaccumulative, and toxic to living organisms. Chemicals such as these are classified as persistent organic pollutants (POPs), and due to their negative environmental …

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Virtual Interactions With Real-Agents For Sustainable Natural Resource Management, Tyler Pierce Jan 2013

Virtual Interactions With Real-Agents For Sustainable Natural Resource Management, Tyler Pierce

Electronic Theses and Dissertations

Common pool resource management systems are complex to manage due to the absence of a clear understanding of the effects of users’ behavioral characteristics. Non-cooperative decision making based on individual rationality (as opposed to group rationality) and a tendency to free ride due to lack of trust and information about other users’ behavior creates externalities and can lead to tragedy of the commons without intervention by a regulator. Nevertheless, even regulatory institutions often fail to sustain natural common pool resources in the absence of clear understanding of the responses of multiple heterogeneous decision makers to different regulation schemes. While modeling …

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Reduced Susceptibility Of Deformation Due To Vibrational And Gravitational Effects On A Focus Variable Adaptive Lens, Victoriya Relina Jan 2013

Reduced Susceptibility Of Deformation Due To Vibrational And Gravitational Effects On A Focus Variable Adaptive Lens, Victoriya Relina

Electronic Theses and Dissertations

Orthodox optical devices, such as lenses, mirrors, and prisms, are composed of solidstate materials, which although well studied and implemented ubiquitously are severely limited in their adaptable properties. An arguably new field of adaptive optics has emerged to further expand photonic manipulation competences of optical components. Fluid-based adaptive optical components were introduced as early as 1968 [1]; such components have the ability to change the shape of their interface surface, thus allowing for a variable curvature profile. The method of manipulation varies greatly, as does the range of surface deformations. A solid-state optical component is affected by system vibration variation …

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Photophysical And Photochemical Factors Affecting Multi-Photon Direct Laser Writing Using The Cross-Linkable Epoxide Su-8, Henry Williams Jan 2013

Photophysical And Photochemical Factors Affecting Multi-Photon Direct Laser Writing Using The Cross-Linkable Epoxide Su-8, Henry Williams

Electronic Theses and Dissertations

For the past decade, the epoxy based photoresist SU-8 has been used commercially and in the lab for fabricating micro- and nano-structures. Investigators have studied how processing parameters such as pre- and post-exposure bake temperatures affect the resolution and quality of SU-8 structures patterned using ultraviolet or x-ray lithography. Despite the advances in understanding the phenomena, not all of them have been explored, especially those that are specific to multi-photon direct laser writing (mpDLW). Unlike conventional exposure techniques, mpDLW is an inherently three-dimensional (3D) process that is activated by nonlinear absorption of light. This dissertation reports how several key processing …

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Mesoscale Light-Matter Interactions, Kyle Douglass Jan 2013

Mesoscale Light-Matter Interactions, Kyle Douglass

Electronic Theses and Dissertations

Mesoscale optical phenomena occur when light interacts with a number of different types of materials, such as biological and chemical systems and fabricated nanostructures. As a framework, mesoscale optics unifies the interpretations of the interaction of light with complex media when the outcome depends significantly upon the scale of the interaction. Most importantly, it guides the process of designing an optical sensing technique by focusing on the nature and amount of information that can be extracted from a measurement. Different aspects of mesoscale optics are addressed in this dissertation which led to the solution of a number of problems in …

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Peak Power Scaling Of Nanosecond Pulses In Thulium Based Fiber Lasers, Christian Gaida Jan 2013

Peak Power Scaling Of Nanosecond Pulses In Thulium Based Fiber Lasers, Christian Gaida

Electronic Theses and Dissertations

Thulium based fiber lasers represent a promising alternative for pulse energy scaling and high peak power generation with ytterbium based systems at 1µm. Advantages of thulium arise from the operation at longer wavelengths and a large gain bandwidth (1.8-2.1µm). Nonlinear effects, such as self phase modulation, stimulated Raman scattering and stimulated Brillouin scattering generally limit peak power scaling in fiber lasers. The longer wavelength of thulium fiber lasers and large mode field areas can significantly increase the nonlinear thresholds. Compared to 1µm systems, thulium fiber lasers enable single mode guidance for two times larger mode field diameter in step index …

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Shear-Wave Imaging And Birefringence In A Complex Near-Surface Geological Environment, Ali Z. Almayahi Jan 2013

Shear-Wave Imaging And Birefringence In A Complex Near-Surface Geological Environment, Ali Z. Almayahi

Theses and Dissertations--Earth and Environmental Sciences

Multiple geophysical and geological data sets were compiled, reprocessed, and interpreted using state-of-the-art signal processing and modeling algorithms to characterize the complex post-Paleozoic geology that overlies the southwestern projection of the Fluorspar Area Fault Complex (FAFC) in western Kentucky. Specific data included 21.5 km of SH-wave seismic reflection, 1.5 km of P-wave seismic reflection, 2 km of electrical resistivity, vertical seismic profiles, Vp and Vs sonic-suspension logs, and 930 lithologic borehole logs. The resultant model indicates three general northeast–southwest-oriented fault zones pass through the study area as southwestern extensions of parts of the FAFC. These fault zones form two significant …

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Generalized Least-Squares Regressions Ii: Theory And Classification, Nataniel Greene Jan 2013

Generalized Least-Squares Regressions Ii: Theory And Classification, Nataniel Greene

Publications and Research

In the first paper of this series, a variety of known and new symmetric and weighted least-squares regression methods were presented with efficient derivations. This paper continues and generalizes the previous work with a theory for deriving, analyzing, and classifying all symmetric and weighted least-squares regression methods.

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Precision Measurement Of The Most Distant Spectroscopically Confirmed Supernova Ia With The Hubble Space Telescope, D Rubin, R A. Knop, E Rykoff, G Aldering, R Amanullah, K Barbary, M S. Burns, A Conley, N Connolly, S Deustua, V Fadeyev, H K. Fakhouri, A S. Fruchter, R A. Gibbons, G Goldhaber, A Goobar, E Y. Hsiao, Xiaosheng Huang, M Kowalski, C Lidman, J Meyers, J Nordin, S Perlmutter, C Saunders, A Spadafora, V Stanishev, N Suzuki, L Wang, Supernova Cosmology Project Jan 2013

Precision Measurement Of The Most Distant Spectroscopically Confirmed Supernova Ia With The Hubble Space Telescope, D Rubin, R A. Knop, E Rykoff, G Aldering, R Amanullah, K Barbary, M S. Burns, A Conley, N Connolly, S Deustua, V Fadeyev, H K. Fakhouri, A S. Fruchter, R A. Gibbons, G Goldhaber, A Goobar, E Y. Hsiao, Xiaosheng Huang, M Kowalski, C Lidman, J Meyers, J Nordin, S Perlmutter, C Saunders, A Spadafora, V Stanishev, N Suzuki, L Wang, Supernova Cosmology Project

Physics and Astronomy

We report the discovery of a redshift 1.71 supernova in the GOODS North field. The Hubble Space Telescope (HST) ACS spectrum has almost negligible contamination from the host or neighboring galaxies. Although the rest frame sampled range is too blue to include any Si ii line, a principal component analysis allows us to confirm it as a Type Ia supernova with 92% confidence. A recent serendipitous archival HST WFC3 grism spectrum contributed a key element of the confirmation by giving a host-galaxy redshift of 1.713 +/- 0.007. In addition to being the most distant SN Ia with spectroscopic confirmation, this …

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The Escape Fraction Of Ionizing Radiation From Galaxies, A Benson, Aparna Venkatesan, J Shull Jan 2013

The Escape Fraction Of Ionizing Radiation From Galaxies, A Benson, Aparna Venkatesan, J Shull

Physics and Astronomy

The escape of ionizing radiation from galaxies plays a critical role in the evolution of gas in galaxies, and the heating and ionization history of the intergalactic medium. We present semi-analytic calculations of the escape fraction of ionizing radiation for both hydrogen and helium from galaxies ranging from primordial systems to disk-type galaxies that are not heavily dust-obscured. We consider variations in the galaxy density profile, source type, location, and spectrum, and gas overdensity/distribution factors. For sufficiently hard first-light sources, the helium ionization fronts closely track or advance beyond that of hydrogen. Key new results in this work include calculations …

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Characterization Of The Supersonic Flowing Microwave Discharge Using Two Dimensional Plasma Tomography, Milka Nikolic, A. Samolov, F. Čučkov, S. Popović, L. Vušković, A. Godunov Jan 2013

Characterization Of The Supersonic Flowing Microwave Discharge Using Two Dimensional Plasma Tomography, Milka Nikolic, A. Samolov, F. Čučkov, S. Popović, L. Vušković, A. Godunov

Physics and Astronomy

A tomographic numerical method based on the two-dimensional Radon formula for a cylindrical cavity has been employed for obtaining spatial distributions of the argon excited levels. The spectroscopy measurements were taken at different positions and directions to observe populations of excited species in the plasmoid region and the corresponding excitation temperatures. Excited argon states are concentrated near the tube walls, thus, confirming the assumption that the post discharge plasma is dominantly sustained by travelling surface wave. An automated optical measurement system has been developed for reconstruction of local plasma parameters of the plasmoid structure formed in an argon supersonic flowing …

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Using Best Professional Judgment To Create Biological Benchmarks For Habitat Assessment Of Wetlands And Oak Savannas In Northwestern Indiana, Brad Gordon Jan 2013

Using Best Professional Judgment To Create Biological Benchmarks For Habitat Assessment Of Wetlands And Oak Savannas In Northwestern Indiana, Brad Gordon

Master of Environmental Science (MES) Theses

The Tolleston Strandplain at the southern end of Lake Michigan offers a unique “dune and swale” topography supporting oak savannas on the dunes and a mosaic of wetland communities in the swales. Following years of human degradation, the sites in this area are now being restored. In this effort, assessments of vegetative quality in these sites have been necessary for proper management decisions. However, it is poorly understood what indices best reflect the vegetative quality of these oak savannas and wetlands. A potential method for determining the best indices for these community types is to use benchmarks that employ expert …

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The Planet, 2013, Winter, James Rogerts, Huxley College Of The Environment, Western Washington University Jan 2013

The Planet, 2013, Winter, James Rogerts, Huxley College Of The Environment, Western Washington University

The Planet

No abstract provided.

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Reflections On Problem Solving Theory And Practice, Alan H. Schoenfeld Jan 2013

Reflections On Problem Solving Theory And Practice, Alan H. Schoenfeld

The Mathematics Enthusiast

In this article, the author reflects on the current state of mathematical problem solving, both in theory and in instruction. The impact of the book Mathematical Problem solving (Schoenfeld, 1985) is also discussed, along with implications of problem solving today with the advent of 21st century technologies.

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Prospective Teachers’ Interactive Visualization And Affect In Mathematical Problem-Solving, Inés Mª Gómez-Chacón Jan 2013

Prospective Teachers’ Interactive Visualization And Affect In Mathematical Problem-Solving, Inés Mª Gómez-Chacón

The Mathematics Enthusiast

Research on technology-assisted teaching and learning has identified several families of factors that contribute to the effective integration of such tools. Focusing on one such family, affective factors, this article reports on a qualitative study of 30 prospective secondary school mathematics teachers designed to acquire insight into the affect associated with the visualization of geometric loci using GeoGebra. Affect as a representational system was the approach adopted to gain insight into how the use of dynamic geometry applications impacted students’ affective pathways. The data suggests that affect is related to motivation through goals and self-concept. Basic instrumental knowledge and the …

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Editorial: (Why) Yet Another Issue On Problem Solving?, Bharath Sriraman Jan 2013

Editorial: (Why) Yet Another Issue On Problem Solving?, Bharath Sriraman

The Mathematics Enthusiast

No abstract provided.

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Problem Solving And Its Elements In Forming Proof, Joanna Mamona-Downs, Martin Downs Jan 2013

Problem Solving And Its Elements In Forming Proof, Joanna Mamona-Downs, Martin Downs

The Mathematics Enthusiast

The character of the mathematics education traditions on problem solving and proof are compared, and aspects of problem solving that occur in the processes of forming a proof, which are not well represented in the literature, are portrayed.

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Developing Problem Solving Experiences In Practical Action Projects, François Pluvinage Jan 2013

Developing Problem Solving Experiences In Practical Action Projects, François Pluvinage

The Mathematics Enthusiast

Problem solving doubtless is an essential element of mathematical learning, so that mathematics educators often are satisfied when finding situations that lead their students to such activity. But in many cases, the chosen situations and the ways to guide students' works are not sufficiently analyzed from a didactic point of view. Our goal in the present analysis is to underline the possible ways for managing the situations, and to exhibit the parameters that educators have at their disposition within their role as mediator between students and mathematical knowledge and know-how.

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Cognition And Affect In Mathematics Problem Solving With Prospective Teachers, Lorenzo J. Blanco, Eloisa Guerrero Barona, Ann Caballero Carrasco Jan 2013

Cognition And Affect In Mathematics Problem Solving With Prospective Teachers, Lorenzo J. Blanco, Eloisa Guerrero Barona, Ann Caballero Carrasco

The Mathematics Enthusiast

Recent studies relating the affective domain with the teaching and learning of mathematics, and more specifically with mathematics problem solving, have focused on teacher education. The authors of these studies have been ever more insistently pointing to the need to design educational programs that take an integrated cognitive and affective approach to mathematics education. Given this context, we have designed and implemented a program of intervention on mathematics problem solving for prospective primary teachers. We here describe some results of that program.

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Framing The Use Of Computational Technology In Problem Solving Approaches, Manuel Santos-Trigo, Matías Camacho Machín Jan 2013

Framing The Use Of Computational Technology In Problem Solving Approaches, Manuel Santos-Trigo, Matías Camacho Machín

The Mathematics Enthusiast

Mathematical tasks are key ingredient to foster teachers and students’ development and construction of mathematical thinking. The use of distinct computational tools offers teachers a variety of ways to represent and explore mathematical tasks which often extends problem solving approaches based on the use of paper and pencil. We sketch a framework to characterize ways of reasoning that emerge as result of using computational technology to solve a task that involves dealing with variation phenomena.

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Tme Volume 10, Numbers 1 And 2 Jan 2013

Tme Volume 10, Numbers 1 And 2

The Mathematics Enthusiast

No abstract provided.

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Compressional And Em Wave Velocity Anisotropy In A Temperate Glacier Due To Basal Crevasses, And Implications For Water Content Estimation, John Bradford, Joshua Nichols, Joel T. Harper, Toby W. Meierbachtol Jan 2013

Compressional And Em Wave Velocity Anisotropy In A Temperate Glacier Due To Basal Crevasses, And Implications For Water Content Estimation, John Bradford, Joshua Nichols, Joel T. Harper, Toby W. Meierbachtol

Geosciences Faculty Publications

We have conducted a series of experiments designed to investigate elastic and electromagnetic (EM) velocity anisotropy associated with a preferentially aligned fracture system on a temperate valley glacier in south-central Alaska, USA. Measurements include a three-dimensional compressional wave (P-wave) seismic reflection survey conducted over a 300 m x 300 m survey patch, with uniform source grid and static checkerboard receiver pattern. Additionally, we acquired a multiazimuth, multi-offset, polarimetric groundpenetrating radar (GPR) reflection experiment in a wagon-wheel geometry with 94 degrees of azimuthal coverage. Results show azimuthal variation in the P-wave normal-moveout velocity of less than 3% (3765 and 3630 ms …

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