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Articles 1 - 14 of 14
Full-Text Articles in Physics
Coursenetworking And Community: Linking Online Discussion Networks And Course Success, Adrienne L. Traxler, Andrew Gavrin, Rebecca Lindell
Coursenetworking And Community: Linking Online Discussion Networks And Course Success, Adrienne L. Traxler, Andrew Gavrin, Rebecca Lindell
Physics Faculty Publications
Large introductory science courses are isolating for many students, and reducing this isolation is an important factor for student retention in college. Active learning courses often build community among students as an explicit goal, but many commuter or non-traditional students have limited on-campus time. Online discussion forums provide one tool for engaging students with each other outside of class time. This study uses social network analysis with forum data from an introductory physics course to examine students' positions in the class discussion network and link it to their final course grades. We find that, contrary to expectations, there is no …
Non-Traditional Students' Conceptual Scores And Network Centrality In Scale-Up Classrooms, Emily N. Sandt, Adrienne L. Traxler
Non-Traditional Students' Conceptual Scores And Network Centrality In Scale-Up Classrooms, Emily N. Sandt, Adrienne L. Traxler
Physics Faculty Publications
As classrooms transition from traditional to cooperative learning environments, questions about the details of these environments effectiveness are posed. Does this model equally benefit all students? How do nontraditional (NT) students' gains in conceptual knowledge compare to those of traditional (Trad) students in these classrooms? Do NT students' social differences (i.e. age, employment status, family life, etc.) affect the amount of learning they do in the course or their tendency to form collaborative ties with other students? In three sections of SCALE-UP introductory calculus-based physics, we collected social network survey data about student connections and used the Force Concept Inventory …
Photoexcited Carrier Trapping And Recombination At Fe Centers In Gan, T. K. Uždavinys, S. Marcinkevičius, J. H. Leach, K. R. Evans, David C. Look
Photoexcited Carrier Trapping And Recombination At Fe Centers In Gan, T. K. Uždavinys, S. Marcinkevičius, J. H. Leach, K. R. Evans, David C. Look
Physics Faculty Publications
Fe doped GaN was studied by time- resolved photoluminescence (PL) spectroscopy. The shape of PLtransients at different temperatures and excitation powers allowed discrimination between electron and hole capture to Fe3+ and Fe2+ centers, respectively. Analysis of the internal structure of Fe ions and intra-ion relaxation rates suggests that for high repetition rates of photoexciting laser pulses the electron and hole trapping takes place in the excited state rather than the ground state of Fe ions. Hence, the estimated electron and hole capture coefficients of 5.5 × 10−8 cm3/s and 1.8 × 10−8 cm3/s should be attributed to excited Fe3+ and …
Ultrafast Saturation Of Electronic-Resonance-Enhanced Coherent Anti-Stokes Raman Scattering And Comparison For Pulse Durations In The Nanosecond To Femtosecond Regime, Anil K. Patnaik, Sukesh Roy, James R. Gord
Ultrafast Saturation Of Electronic-Resonance-Enhanced Coherent Anti-Stokes Raman Scattering And Comparison For Pulse Durations In The Nanosecond To Femtosecond Regime, Anil K. Patnaik, Sukesh Roy, James R. Gord
Physics Faculty Publications
The saturation threshold of a probe pulse in an ultrafast electronic-resonance-enhanced (ERE) coherent anti-Stokes Raman spectroscopy (CARS) configuration is calculated. We demonstrate that while the underdamping condition is a sufficient condition for saturation of ERE-CARS with the long-pulse excitations, a transient gain must be achieved to saturate the ERE-CARS signal for the ultrafast probe regime. We identify that the area under the probe pulse can be used as a definitive parameter to determine the criterion for a saturation threshold for ultrafast ERE-CARS. From a simplified analytical solution and a detailed numerical calculation based on density-matrix equations, the saturation threshold of …
Improved Sensitivity Mems Cantilever Sensor For Terahertz Photoacoustic Spectroscopy, Ronald A. Coutu Jr., Ivan Medvedev, Douglas T. Petkie
Improved Sensitivity Mems Cantilever Sensor For Terahertz Photoacoustic Spectroscopy, Ronald A. Coutu Jr., Ivan Medvedev, Douglas T. Petkie
Physics Faculty Publications
In this paper, a microelectromechanical system (MEMS) cantilever sensor was designed, modeled and fabricated to measure the terahertz (THz) radiation induced photoacoustic (PA) response of gases under low vacuum conditions. This work vastly improves cantilever sensitivity over previous efforts, by reducing internal beam stresses, minimizing out of plane beam curvature and optimizing beam damping. In addition, fabrication yield was improved by approximately 50% by filleting the cantilever’s anchor and free end to help reduce high stress areas that occurred during device fabrication and processing. All of the cantilever sensors were fabricated using silicon-on-insulator (SOI) wafers and tested in a custom …
Heating Power Of Coated Fecov Magnetic Nanoparticles, Hanaa Ali Alshammari
Heating Power Of Coated Fecov Magnetic Nanoparticles, Hanaa Ali Alshammari
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The effect of coatings on the heating curves of magnetic nanoparticles was studied in this Thesis. Iron cobalt vanadium (FeCoV) nanoparticles with oxide (CoOFe2O3) and graphite (C) coating to prevent oxidation, were synthesized through thermal plasma processing method. The magnetic nanoparticles had an average diameter of 30 nm. In the case of FeCoV with oxide coating, the initial diameter of the pure FeCoV nanoparticles on average was 30 nm but after oxidation 5 nm thick oxide layer was created. As a result of this oxidation, the magnetic core of FeCoV nanoparticles was shrunk from 30 nm to 20 nm in …
A Social Network Analysis Of An Introductory Calculus-Based Physics Class With Comparisons Of Traditional And Non-Traditional Students, Fci Scores, And Network Centralities, Emily Sandt
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The use of social network analysis in physics education research seeks to advance understanding of how students' collaborative tendencies influence trends of learning. Common useful measurements are network size, density of connections, and centrality measures that describe the importance of nodes' positions. This study compared four different centrality measures at the beginning and end of seven sections of an introductory calculus-based physics course. The Force Concept Inventory was used as a measure of conceptual learning at pre- and post-course administrations. The main focus of this study was to identify if differences in network centralities and conceptual learning/knowledge exist with respect …
Surface Effect Of Ferromagnetic Nanoparticles On Transition Between Single- And Multi-Domain Structure Or Between Single-Domain Structure And Superparamagnetic Phase, Hind Adawi
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Surface effects on critical dimensions of ferromagnetic nanoparticles were studied. Algebraic equations were derived and numerically solved for critical radius RC2 of ferromagnetic nanoparticles describing the transition between single- and multi-domain magnetic structure. Results were analyzed to illustrate the effect of surface parameters related to saturation magnetization a, exchange interaction ß, and anisotropy KS on the critical radius of nanoparticles with a core value of anisotropy KV. Available experimental data for MnBi, FePt, and CoPt or for Fe nanoparticles were used as examples of nanoparticles with high and low values of KV, respectively. Our studies clearly show that discrepancies existing …
Social Network Analysis And The Representation Of Female Students In Introductory Undergraduate Physics, Sarah Teresa Hierath
Social Network Analysis And The Representation Of Female Students In Introductory Undergraduate Physics, Sarah Teresa Hierath
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Physics Education Research has begun to focus on the learning habits, success, and connections of students in physics classrooms using Social Network Analysis (SNA). SNA is an important tool in studying classroom dynamics because it can be used to map the social structure of a classroom's interactions and to aid in understanding how students work and study together. This study presents network diagrams, statistics, centrality measures, and conceptual understanding correlations for 7 different sections of introductory physics. Centrality measures were determined from a first and last week survey in which students were asked to indicate their study partners within the …
Millimeter – Wave/Terahertz Chirped Michelson Interferometer Techniques For Sub Surface Sensing, Dinesh Amal Mirando
Millimeter – Wave/Terahertz Chirped Michelson Interferometer Techniques For Sub Surface Sensing, Dinesh Amal Mirando
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Over the last couple of decades, the field of millimeter-wave (mmW) and terahertz (THz) radiation has seen an accelerated growth thanks to developments in high quality mmW/THz sensors. These developments have contributed to many useful applications in the fields of medicine, security, construction, etc. Non-destructive evaluations such as the detection of defects in materials is currently one of the major applications of mmW/THz radiation. These evaluations are performed using mmW/THz continuous-wave radar systems. In this study, we discuss how Frequency Modulated Continuous Wave (FMCW) techniques can enhance sensing applications through the use of a Michelson interferometer. This allows multiple objects …
Terahertz Spectroscopic Breath Analysis As A Viable Analytical Chemical Sensing Technique, Robert M. Schueler
Terahertz Spectroscopic Breath Analysis As A Viable Analytical Chemical Sensing Technique, Robert M. Schueler
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The ability to quantify trace chemicals in human breath enables the possibility of identifying breath biomarkers to aid in diagnosis. The vast majority of the studies in the analytical breath analysis rely on GC-MS techniques for quantification of the human breath composition1,2,3,4. THz spectroscopy of breath is rapid, sensitive, and highly specific molecular identification in complex mixtures containing 10-100 analytes with near `absolute' specificity. THz spectroscopic breath analyzers require chemical preconcentration. A newly developed custom preconcentrator was constructed and compared in its performance to a commercial system. Unlike the commercial counterpart, the new system does not require cryogenic liquids, is …
Correlations Between Introductory Students’ Attitudes About Physics And Conceptual Understanding, Raym Alzahrani
Correlations Between Introductory Students’ Attitudes About Physics And Conceptual Understanding, Raym Alzahrani
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The purpose of this study is to measure correlations between the students’ incoming attitudes, beliefs and expectations about physics and their conceptual understanding. The study presents a profile of the attitudes and beliefs for Wright State University students who enrolled in calculus-based General Physics I courses during academic years 2014-2015 and 2015-2016. Students’ initial and final attitudes, measured using the CLASS, are correlated with initial and final conceptual gain, measured using the Force Concept Inventory. Students’ initial attitudes (Opre) was correlated with students’ gain (FCIgain) in many sections. Correlations between students’ final attitudes (Opost) and their conceptual understanding (FCIpost), reported …
High Powered Pulsed Terahertz Light Generation From Superconducting Antenna Arrays, Nicholas C. Padgett
High Powered Pulsed Terahertz Light Generation From Superconducting Antenna Arrays, Nicholas C. Padgett
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Terahertz radiation is invaluable for use in spectroscopy and imaging work due to its nondestructive nature. It has become a key focus for those wishing to develop sensors capable of detecting weapons and narcotics unobtrusively and at a distance as well as characterizing materials and identifying defects. An ultrafast pulsed (femtoseconds) laser incident on a superconducting ring has been predicted to cause the emission of terahertz (THz) radiation. It is theorized that the radiation is a result of the supercurrent being modulated by the breaking and recombining of Cooper pairs on the order of picoseconds, where the time scale determines …
Use Of Clearview Gel Dosimeter For Quality Assurance And Testing Of Stereotactic Radiosurgery, Erik Joseph-Leonard Courter
Use Of Clearview Gel Dosimeter For Quality Assurance And Testing Of Stereotactic Radiosurgery, Erik Joseph-Leonard Courter
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There exists a lack of accurate, reproducible three-dimensional dosimetry techniques for stereotactic radiosurgery (SRS) commissioning and quality assurance. This experiment evaluates the use of ClearView gel dosimeters as an alternative to current methods for small field dosimetry in SRS testing. ClearView differs from other gel dosimeters in that it uses tetrazolium salt in its chemical make-up in place of traditional Fricke-type compounds. Using a Varian TrueBeam radiotherapy system to deliver the radiation, three vials of ClearView gel dosimeter were tested in three different dose delivery scenarios. The first test examined the dosimeter's response to a static beam with the dose …