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Full-Text Articles in Physics
Direct Parameter Fitting Of Action Potentials In Skeletal Muscle Cells Which Include Longitudinal Segments, Tyme Suda
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Excitation of skeletal muscle cells triggers a large voltage spike known as an action potential (AP), leading to muscle contraction. Modeling of an AP is typically done using the method developed by scientists Hodgkin and Huxley (HH). In the HH method, voltage and time gated Na+ and K+ ionic currents are simulated, along with a positive “Leak” ionic current and capacitive current. Due to the complexity and the computational time required for simulation, direct fitting of HH parameters to experimental APs has rarely been attempted. A previous thesis at Wright State performed direct fitting for the case of a single …
Using Network Analysis To Contrast Three Models Of Student Forum Discussions, Hannah N. Benston
Using Network Analysis To Contrast Three Models Of Student Forum Discussions, Hannah N. Benston
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There is much research about how actors and events in social networks affect each other. In this research, three network models were created for discussion forums in three semesters of undergraduate general physics courses. This study seeks to understand what social network measures are most telling of a online forum classroom dynamic. That is, I wanted to understand more about things like what students are most central to the networks and whether this is consistent across different network models. I also wanted to better understand how students may or may not group together. What relationships (student to student, student to …
Establishing A Machine Learning Framework For Discovering Novel Phononic Crystal Designs, Drew Feltner
Establishing A Machine Learning Framework For Discovering Novel Phononic Crystal Designs, Drew Feltner
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A phonon is a discrete unit of vibrational motion that occurs in a crystal lattice. Phonons and the frequency at which they propagate play a significant role in the thermal, optical, and electronic properties of a material. A phononic material/device is similar to a photonic material/device, except that it is fabricated to manipulate certain bands of acoustic waves instead of electromagnetic waves. Phononic materials and devices have been studied much less than their photonic analogues and as such current materials exhibit control over a smaller range of frequencies. This study aims to test the viability of machine learning, specifically neural …
The Effects Of An Ultrafast Pulsed Laser On Ybco Thin Film Circuit Transients, Matthew L. Rustad
The Effects Of An Ultrafast Pulsed Laser On Ybco Thin Film Circuit Transients, Matthew L. Rustad
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Terahertz (THz) frequency light has shown promise for a wide variety of applications due to its material characterization and imaging capabilities. Its nondestructive nature coupled with its submillimeter spatial resolution provides the most value for terahertz light as an imaging tool. The application of terahertz technology has been limited by a lack of novel and powerful sources. It has been shown that that Yttrium Barium Copper Oxide (YBCO), a type II superconductor, has certain properties that would allow YBCO to be an effective source for THz light. Recent microwave work has shown that when a persistent supercurrent is placed on …
Finite Different Time-Domain Simulation Of Terahertz Waves Propagation Through Unmagnetized Plasma, Aditha Srikantha Senarath
Finite Different Time-Domain Simulation Of Terahertz Waves Propagation Through Unmagnetized Plasma, Aditha Srikantha Senarath
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In order to support ongoing terahertz time-domain spectroscopic experiments involving plasma characterization, it is beneficial to simulate the interaction of THz pulses with varying plasma configurations. In this approach, a 1-D Finite Difference Time Domain (FDTD) model was constructed to simulate the interaction of terahertz radiation with a plasma medium. In order to incorporate the plasma properties into the simulation, a Z-transformation was applied. This model is capable of simulating the following properties of plasmas including electron density, collision frequency, and the interaction length of the plasma medium. The simulated model was characterized using terahertz time-domain spectroscopy. The effects of …
Development Of Embedded Atom Method Interatomic Potentials For Ge-Sn-Si Ternary And Constituent Binary Alloys For Modeling Material Crystallization, Sudip Acharya
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Group IV elements based nanoelectronics devices (mainly Si and Ge based devices) have been developed and improved over a long period of time and are the most influencing materials of semiconductor electronics, but due to their indirect bandgap their use in optoelectronics is limited. Alternatively, new Group IV alloys comprised of Ge, Si, and Sn semiconductor materials have emerged as attractive options for various electronic and optoelectronic applications. The binary and ternary alloys provide strain and energy bandgap engineering by controlling element content, a route for realizing direct-transition semiconductors, improvement in interface and defect properties, and a reduction of the …
Characterization Of A Novel Terahertz Chemical Sensor, Daniel J. Tyree
Characterization Of A Novel Terahertz Chemical Sensor, Daniel J. Tyree
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A recently constructed novel analytical tabletop terahertz (THz) chemical sensor capable of detecting a wide range of gases with high sensitivity and specificity was characterized to assess its performance over a range of operational parameters. The sensor was designed with an objective of quantifying composition of exhaled human breath, where target concentrations span part per trillion (ppt) to part per billion (ppb) level of dilutions. The sensor utilizes terahertz rotational spectroscopy of sampled gases for quantification of dilutions. The sensor occupies a volume of ~ 2 ft3 and incorporates a coiled absorption cell, thermal desorption tubes, and all necessary electronic …
Evolution Of Electron Properties After Nanosecond Repetitively Pulsed Discharges In Air Measured By Thomson Scattering, Chase S. Murray
Evolution Of Electron Properties After Nanosecond Repetitively Pulsed Discharges In Air Measured By Thomson Scattering, Chase S. Murray
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This work was an investigation of nanosecond repetitively pulsed discharges in air by measuring the evolution of electron density and electron temperature between pulses using Thomson scattering of laser light. Bursts of repetitive pulses within several microseconds after the initial pulse were found to exhibit a coupling effect and create an even higher electron density than the initial pulse. The wide range of temperatures and densities of the electrons existing between pulses allow an opportunity to explore both the collective and non-collective regimes of Thomson scattering. By measuring electron density and temperature at a variety of times, an accurate description …
One-Dimensional Kinetic Particle-In-Cell Simulations Of Various Plasma Distributions, Richard N. Vanderburgh
One-Dimensional Kinetic Particle-In-Cell Simulations Of Various Plasma Distributions, Richard N. Vanderburgh
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A one-dimensional kinetic particle-in-cell (PIC) MATLAB simulation was created to demonstrate the time-evolution of various plasma distributions. Building on previous plasma PIC programs written in FORTRAN and Python, this work recreates the computational and diagnostic tools of these packages in a more user- and educational-friendly development environment. Plasma quantities such as plasma frequency and species charge-mass ratios are arbitrarily defined. A one-dimensional spatial environment is defined by total length and number and size of spatial grid points. In the first time-step, charged particles are given initial positions and velocities on a spatial grid. After initialization, the program solves for the …
The Magnetocaloric Effect & Performance Of Magnetocaloric Materials In A 1d Active Magnetic Regenerator Simulation, Daniel Nicholas Bayer
The Magnetocaloric Effect & Performance Of Magnetocaloric Materials In A 1d Active Magnetic Regenerator Simulation, Daniel Nicholas Bayer
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Active magnetic regenerators (AMRs) operate according to the magnetothermal phenomenon known as the magnetocaloric effect (MCE), and are at the forefront of magnetic cooling technology. AMR simulations have been shown to be useful tools in predicting the performance of different magnetocaloric materials (MCMs) without the need to develop a physical prototype. In a search to determine the set of operational parameters which would maximize MCM performance, a 1D simulation of an AMR device has been developed in Matlab. Gadolinium, the most well-documented MCM, is used as a benchmark material to study the effects of varying certain operational parameters such as …
Establishing A Quality Assurance Routine For Digital Imaging, Sulaiman Rana Al
Establishing A Quality Assurance Routine For Digital Imaging, Sulaiman Rana Al
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In the clinical medical physics field, Quality Assurance (QA) is a fundamental topic to insure patient safety and effective treatment. In recent years, the imaging hardware for diagnostic x-rays has been shifting to fully digital detectors. However, the quality assurance tests for such detectors in the clinical setting is still under development. In the Medical Imaging Department of Kettering Hospital (Kettering, OH), the currently accepted method of performing QA on detectors is to use an extensive set of tests suggested by the manufacturer. This set of tests requires about 90 minutes, which is too long for daily use. The goal …
Multiscale Modeling Of Carbon Nanotube Synthesis In A Catalytic Chemical Vapor Deposition Reactor, Jonathan Troville
Multiscale Modeling Of Carbon Nanotube Synthesis In A Catalytic Chemical Vapor Deposition Reactor, Jonathan Troville
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The bottom-up analysis of Carbon Nanotube synthesis is not well understood. Specifically, the question as to how carbon adsorbs to a substrate inclusive of a supported catalyst may lead to the energetically favorable structure of a hexagonal close- packed structure along the wall, or walls, of the tube. A first time simulation using COMSOL Multiphysics has been generated in order to capture the gas-phase mech- anism which leads to carbon production. It is thought that the carbon adsorbs and the walls are formed from the bottom up and the inside out for multi-wall CNTs. The studies involved accurately setting up …
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 …
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 …
Assessment Of The Applicability Of Terahertz Spectroscopic Breath Sensing Towards Monitoring Type 1 Diabetic Mellitus, Jessica Rose Thomas
Assessment Of The Applicability Of Terahertz Spectroscopic Breath Sensing Towards Monitoring Type 1 Diabetic Mellitus, Jessica Rose Thomas
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Type 1 diabetes is a condition that cumulatively costs around $14.9 billion in medical expenses every year in the United States. Besides being costly, the monitoring of this disease is invasive, painful, and often embarrassing to the afflicted individual; blood and urine testing is currently the daily method of monitoring blood glucose and ketone levels in the body of type 1 diabetics. Though the use of these samples is standard, another avenue for possibly determining blood glucose has not been completely explored. With over 3000 chemicals reportedly found in exhaled human breath, biomarkers associated with this disorder and many of …
Chemical Analysis Of Exhaled Breath By Means Of Terahertz Rotational Spectroscopy, Tianle Guo
Chemical Analysis Of Exhaled Breath By Means Of Terahertz Rotational Spectroscopy, Tianle Guo
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Terahertz spectroscopy, due to the high sensitivity and specificity that it affords, has been incorporated in many fields to aid in the chemical analysis of gases. One potential application is to detect bio-markers in human breath for early diagnosis. Our current aim of our research is to establish a relationship between several chemicals and the glucose levels from human exhaled breath. 20 chemical including Acetone, Carbon monoxide (CO), Methanol were studied. Volunteers' breath samples were processed through a pre-concentration system before being injected into the spectrometer. Initially, a commercial preconcentration system, Entech 7100A, was used. However, due to the limitations …
Characterization Of Ceramic Matrix Composite Materials Using Millimeter-Wave Techniques, Matthew Lee Bischoff
Characterization Of Ceramic Matrix Composite Materials Using Millimeter-Wave Techniques, Matthew Lee Bischoff
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This thesis describes studies that were carried out on Ceramic Matrix Composite (CMC) materials. These materials were provided by the Air Force Research Laboratory for evaluation in the millimeter-wave frequency region with the goal of developing Non-Destructive Evaluation techniques. This thesis centers on describing the measured reflections from an Oxide/Oxide and SiC/SiNC CMC materials. Models were derived from the Fresnel equations to account for the reflected and transmitted waves in these materials. System models were developed to describe the power coupling of the spectra measured in three separate measurement systems. Using these models the complex index of refraction was determined …
The Mechanisms Of Luminescence From Zno Under Electron Irradiation, Devin Marlinjames Todd
The Mechanisms Of Luminescence From Zno Under Electron Irradiation, Devin Marlinjames Todd
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Zinc Oxide has been utilized for centuries in a wide range of applications including medical, food, and materials. It is now that ZnO draws much attention to its potential as a high frequency semiconductor and UV laser. As a result, there has been much investigation into the properties of ZnO and many papers have been published in the area. Despite this fact, there is still much that is unknown about its electronic defect structure. This research investigates the broad region of the Zinc Oxide luminescence spectrum known as the green band, which lies roughly between 480 - 580 nm or …