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Full-Text Articles in Physics

Investigation Of The Chemical Kinetics In An Atmospheric Cold Plasma Towards Co2 Conversion, Daniel Piatek Aug 2020

Investigation Of The Chemical Kinetics In An Atmospheric Cold Plasma Towards Co2 Conversion, Daniel Piatek

Seton Hall University Dissertations and Theses (ETDs)

Hydrogenation of carbon dioxide (CO2) to methanol (CH3OH) is a promising route for utilization of excess and residual CO2. The conversion of CO to methanol is a well-developed process but the ability to use CO2 as a feed gas still requires high pressures (30-300 atm) to attain conversion. In this work, the hydrogenation of CO2 is explored using H2O as well as H2 in an atmospheric pressure nonthermal (cold) plasma created with a dielectric barrier discharge (DBD) reactor. Different gas mixtures such as argon (Ar) and helium (He) are used to understand their interactions in the process of CO2 hydrogenation ...


Characterization Of A Novel Double Cooled Electrode Dbd Reactor For Ozone Generation, Gustavo Duarte Aug 2020

Characterization Of A Novel Double Cooled Electrode Dbd Reactor For Ozone Generation, Gustavo Duarte

Seton Hall University Dissertations and Theses (ETDs)

The Dielectric Barrier Discharge (DBD) is used to generate atmospheric or higher-pressure non-thermal plasmas and has found various commercial applications such as in industrial large-scale ozone generation. Ozone (O3 ) is a powerful chemical reactant that is used to kill bacteria, to deodorize and to perform water purification. The effectiveness of the DBD reactors depends on the electrode arrangements, gap lengths, dielectric materials, operating gases and feed gas quality to name a few. However, the production of O3 is heat sensitive. In order to prevent O3 destruction thermal cooling of the DBD is needed. The industry approach to ...


Electrical And Chemical Characterization Of A Helium-Air Non-Thermal Atmospheric Pressure Plasma Jet, Adam Zandani May 2020

Electrical And Chemical Characterization Of A Helium-Air Non-Thermal Atmospheric Pressure Plasma Jet, Adam Zandani

Seton Hall University Dissertations and Theses (ETDs)

Plasma is one of the most complicated, yet promising fields in physics due to its high efficiency and multitude of crucial applications such as biological sterilization, polymer modification, surface treatments, etching, agriculture, and facilitation of selective catalytic processes to name a few. With these advantages, mysteries still remain. With this in mind, in order to accurately gauge the total influence of the plasma applied in various processes, understanding what is being produced and how the production occurs is vital. To understand this, optical emission spectroscopy was used to gauge how the species generated are influenced by operation parameters such as ...


The Population Densities Of Argon Metastable Levels, Nada Khogeer, Chelsy Gonzalez, Milka Nikolic Apr 2019

The Population Densities Of Argon Metastable Levels, Nada Khogeer, Chelsy Gonzalez, Milka Nikolic

Physics and Astronomy

In this experiment, we used the optical emission spectroscopy (OES) method to obtain the main properties of low temperature Argon plasma. The experiment was sustained in powers and pressures that ranges from 30-100 W and 15-100 mTorr. We used numerical methods for the Argon kinetic model to calculate metastable levels and resonant states for the first excited states in low temperature Argon plasma. By finding the ratio of two spectral lines and finding another ratio from a different upper energy level that goes down to the same two lower energy levels, we can construct a system of two nonlinear equations ...


A Multi-Frequency Study Of Arecibo Pulsars, Timothy Eugene Edward Olszanski Jan 2019

A Multi-Frequency Study Of Arecibo Pulsars, Timothy Eugene Edward Olszanski

Graduate College Dissertations and Theses

Compact Objects (Neutron Stars) form in the last moments of a star's life, during the violent events known as supernovae. As the star's core fusion falters, matter undergoes a dramatic gravitational compression resulting in internal densities rivaling subatomic particles. Ever since their discovery in the mid-twentieth century, these highly magnetized and rapidly rotating balls of condensed matter have provided a bountiful playground for astronomers seeking out exotic physics.

Neutron Stars that emit electromagnetic radiation are seen by observers as Pulsars, named such for the pulse of intensity as the pulsar's radiation beam passes into our line of ...


Designing A Modified Zeeman Slower For The Paschen-Back Magnetic Regime, Leo Michael Nofs Jan 2019

Designing A Modified Zeeman Slower For The Paschen-Back Magnetic Regime, Leo Michael Nofs

Master's Theses and Doctoral Dissertations

Controlled study of high-density plasmas, such as those found in fusion reactions and stars, is difficult due to their highly-magnetized environments. A specialized high magnetic field (High-B) trap was developed at the University of Michigan in Georg Raithel's research group to study such highly magnetized, high density plasmas using rubidium atoms. By replacing the atom source with a Zeeman slower, a well-studied device to slow and cool atoms, the atom flux could be increased by a factor more than 1000, leading to higher High-B plasma densities. The goal of this project is to design a Zeeman slower that differs ...


Evaluation Of X-Ray Spectroscopic Techniques For Determining Temperature And Density In Plasmas, Theodore Scott Lane Jan 2019

Evaluation Of X-Ray Spectroscopic Techniques For Determining Temperature And Density In Plasmas, Theodore Scott Lane

Graduate Theses, Dissertations, and Problem Reports

Temperature and density measurements of plasmas are important for understanding various phenomena. For example, equations of state, most scaling arguments for Inertial Confinement Fusion and laboratory astrophysics all rely upon accurate knowledge of temperature and density. Spectroscopy is a non-invasive technique to measure these quantities. In this work we establish a new spectroscopic technique by using it to determine temperature. We also compare and contrast the capability of two codes, PrismSPECT and ATOMIC, to infer electron density from experimentally acquired spectra via Stark broadening.

We compare and contrast the capability of isoelectronic line ratios and inter-stage line ratios in an ...


Hybrid Iterative Approach For Simulation Of Radio-Frequency Fields In Plasma, Vladimir A. Svidzinski, Jin-Soo Kim, Liangji Zhao, S. A. Galkin, Joseph Andrew Spencer Aug 2018

Hybrid Iterative Approach For Simulation Of Radio-Frequency Fields In Plasma, Vladimir A. Svidzinski, Jin-Soo Kim, Liangji Zhao, S. A. Galkin, Joseph Andrew Spencer

Physics Student Research

A novel iterative approach for solving discretized linear wave equations in a frequency domain, which combines time evolution with iterative relaxation schemes, is presented. In this hybrid approach, each iteration cycle consists of evolution of electromagnetic (EM) fields in time over a specified number of field periods followed by several iterative relaxations. Provided that there is sufficient dissipation, both the time evolution and the iterative relaxations contribute to the convergence of the EM fields to the solution of the formulated full wave boundary value problem. Time evolution rapidly distributes EM fields, propagating with group velocity, over the simulation domain, while ...


Statistical Physics Principles Tested Using Dusty Plasma And Aerosol Experiments, Chun-Shang Wong Aug 2018

Statistical Physics Principles Tested Using Dusty Plasma And Aerosol Experiments, Chun-Shang Wong

Theses and Dissertations

Statistical physics has been the foundation for much of our understanding about plasma physics. Often, plasma physics phenomena are explained using statistical physics principles and theories. Here, I reverse this paradigm to instead use plasma experiments to test statistical physics principles.

In this thesis, I test statistical physics principles with an experimental dusty plasma, which is a four-component mixture of micron-sized ``dust'' particles, electrons, ions, and neutral gas molecules. When immersed in the plasma, the dust particles acquire large negative charges, since they accumulate more electrons than ions. Due to their large electric charges, the dust particles have interparticle potential ...


Kinetic Picture Of Ion Acoustic Wave Reflection Using Laser-Induced Fluorescence, Jorge Alberto Berumen Cantu Aug 2018

Kinetic Picture Of Ion Acoustic Wave Reflection Using Laser-Induced Fluorescence, Jorge Alberto Berumen Cantu

Theses and Dissertations

An examination of the first laser-induced fluorescence measurements of ion-acoustic wave reflection is presented in this dissertation. The experiment is performed in a multipole cylinindrical chamber using singly-ionized argon (ArII) plasma produced by a means of a hot cathode. Ion-acoustic waves are launched from a mesh antenna and reflected/absorbed by a biased, solid boundary (electrode). A kinetic analysis of wave reflection is carried out through LIF's ability of resolving ion phase-space. A comparison between Langmuir probe and LIF diagnostics is presented, with complementary Electric-field probe measurements.


Actinometry Of Hydrogen Plasmas, A. M. Cotter, James Doyle Jun 2018

Actinometry Of Hydrogen Plasmas, A. M. Cotter, James Doyle

Macalester Journal of Physics and Astronomy

Optical emission spectroscopy (OES) can be used to map the electron energy distribution of hydrogen plasmas. Using actinometry, a type of OES where trace amounts of noble gases are introduced, the effect of discharge power on the electron temperature of hydrogen plasmas was explored. This was done using argon and krypton as actinometers for low pressure hydrogen plasmas. It was determined that the electron temperature decreased with respect to power supplied to the discharge.


Hill Functions For Stochastic Gene Regulatory Networks From Master Equations With Split Nodes And Time-Scale Separation, Ovidiu Lipan, Cameron Ferwerda Feb 2018

Hill Functions For Stochastic Gene Regulatory Networks From Master Equations With Split Nodes And Time-Scale Separation, Ovidiu Lipan, Cameron Ferwerda

Physics Faculty Publications

The deterministic Hill function depends only on the average values of molecule numbers. To account for the fluctuations in the molecule numbers, the argument of the Hill function needs to contain the means, the standard deviations, and the correlations. Here we present a method that allows for stochastic Hill functions to be constructed from the dynamical evolution of stochastic biocircuits with specific topologies. These stochastic Hill functions are presented in a closed analytical form so that they can be easily incorporated in models for large genetic regulatory networks. Using a repressive biocircuit as an example, we show by Monte Carlo ...


A Parallel Spectral Method Approach To Model Plasma Instabilities, Kevin S. Scheiman Jan 2018

A Parallel Spectral Method Approach To Model Plasma Instabilities, Kevin S. Scheiman

Browse all Theses and Dissertations

The study of solar-terrestrial plasma is concerned with processes in magnetospheric, ionospheric, and cosmic-ray physics involving different particle species and even particles of different energy within a single species. Instabilities in space plasmas and the earth's atmosphere are driven by a multitude of free energy sources such as velocity shear, gravity, temperature anisotropy, electron, and, ion beams and currents. Microinstabilities such as Rayleigh-Taylor and Kelvin-Helmholtz instabilities are important for the understanding of plasma dynamics in presence of magnetic field and velocity shear. Modeling these turbulences is a computationally demanding processes; requiring large memory and suffer from excessively long runtimes ...


A Molecular Debye-Hückel Theory Of Solvation In Polar Fluids: An Extension Of The Born Model, Tiejun Xiao, Xueyu Song Dec 2017

A Molecular Debye-Hückel Theory Of Solvation In Polar Fluids: An Extension Of The Born Model, Tiejun Xiao, Xueyu Song

Ames Laboratory Accepted Manuscripts

A dielectric response theory of solvation beyond the conventional Born model for polar fluids is presented. The dielectric response of a polar fluid is described by a Born response mode and a linear combination of Debye-Hückel-like response modes that capture the nonlocal response of polar fluids. The Born mode is characterized by a bulk dielectric constant, while a Debye-Hückel mode is characterized by its corresponding Debye screening length. Both the bulk dielectric constant and the Debye screening lengths are determined from the bulk dielectric function of the polar fluid. The linear combination coefficients of the response modes are evaluated in ...


Nonlinear Waves, Instabilities And Singularities In Plasma And Hydrodynamics, Denis Albertovich Silantyev Aug 2017

Nonlinear Waves, Instabilities And Singularities In Plasma And Hydrodynamics, Denis Albertovich Silantyev

Mathematics & Statistics ETDs

This work concentrates on Langmuir wave filamentation instability in the kinetic regime of plasma and computation of Stokes wave with high precision using conformal maps.

Nonlinear effects are present in almost every area of science as soon as one tries to go beyond the first order approximation. In particular, nonlinear waves emerge in such areas as hydrodynamics, nonlinear optics, plasma physics, quantum physics, etc. The results of this work are related to nonlinear waves in two areas, plasma physics and hydrodynamics, united by concepts of instability, singularity and advanced numerical methods used for their investigation.

The first part of this ...


On Laser-Induced Plasma Containing Hydrogen, Ghaneshwar Gautam Aug 2017

On Laser-Induced Plasma Containing Hydrogen, Ghaneshwar Gautam

Doctoral Dissertations

Laser-induced micro-plasma dynamics are investigated in laboratory air, ultra-high-pure hydrogen gas, and hydrogen-nitrogen gas mixtures. The dissertation focuses on atomic spectroscopy of hydrogen in the visible region.

Line-of-sight measurements are analyzed to obtain spatial distributions of electron densities and excitation temperatures. The studies include evaluation of self-absorption phenomena. The plasma dynamics occur initially well above re-entry speeds and diminish to hypersonic and then supersonic expansions. Expansion velocities are measured that are above three hundred times the speed of sound in standard atmosphere. Optical breakdown is induced by using pulsed laser radiation. Emission spectra are collected by employing a spectrometer equipped ...


Accelerator Based Fusion Reactor, Keh-Fei Liu, Alexander Wu Chao Aug 2017

Accelerator Based Fusion Reactor, Keh-Fei Liu, Alexander Wu Chao

Physics and Astronomy Faculty Publications

A feasibility study of fusion reactors based on accelerators is carried out. We consider a novel scheme where a beam from the accelerator hits the target plasma on the resonance of the fusion reaction and establish characteristic criteria for a workable reactor. We consider the reactions d+tn+α, d+3Hep+α and p+11B→3α in this study. The critical temperature of the plasma is determined from overcoming the stopping power of the beam with the fusion energy gain. The needed plasma lifetime is determined from the width of the resonance, the beam ...


The Impact Of Base Stacking On The Conformations And Electrostatics Of Single-Stranded Dna, Alex Plumridge, Steve P. Meisburger, Kurt Andresen, Lois Pollack Feb 2017

The Impact Of Base Stacking On The Conformations And Electrostatics Of Single-Stranded Dna, Alex Plumridge, Steve P. Meisburger, Kurt Andresen, Lois Pollack

Physics and Astronomy Faculty Publications

Single-stranded DNA (ssDNA) is notable for its interactions with ssDNA binding proteins (SSBs) during fundamentally important biological processes including DNA repair and replication. Previous work has begun to characterize the conformational and electrostatic properties of ssDNA in association with SSBs. However, the conformational distributions of free ssDNA have been difficult to determine. To capture the vast array of ssDNA conformations in solution, we pair small angle X-ray scattering with novel ensemble fitting methods, obtaining key parameters such as the size, shape and stacking character of strands with different sequences. Complementary ion counting measurements using inductively coupled plasma atomic emission spectroscopy ...


Laser Shock Wave Assisted Patterning On Niti Shape Memory Alloy Surfaces, Dovletgeldi Seyitliyev, Peizhen Li, Khomidkhodza Kholikov, Byron Grant, Haluk E. Karaca, Ali O. Er Feb 2017

Laser Shock Wave Assisted Patterning On Niti Shape Memory Alloy Surfaces, Dovletgeldi Seyitliyev, Peizhen Li, Khomidkhodza Kholikov, Byron Grant, Haluk E. Karaca, Ali O. Er

Mechanical Engineering Faculty Publications

An advanced direct imprinting method with low cost, quick, and less environmental impact to create thermally controllable surface pattern using the laser pulses is reported. Patterned micro indents were generated on Ni50Ti50 shape memory alloys (SMA) using an Nd:YAG laser operating at 1064 nm combined with suitable transparent overlay, a sacrificial layer of graphite, and copper grid. Laser pulses at different energy densities which generates pressure pulses up to 10 GPa on the surface was focused through the confinement medium, ablating the copper grid to create plasma and transferring the grid pattern onto the NiTi surface ...


Preface To Special Topic: A Tribute To John Lumley, Kiran Bhaganagar, Thomas B. Gatski, William K. George Feb 2017

Preface To Special Topic: A Tribute To John Lumley, Kiran Bhaganagar, Thomas B. Gatski, William K. George

CCPO Publications

This Special Topic Section is dedicated to the life and memory of John Leask Lumley(1930-2015), professor and scientist extraordinaire.


Regionally Implicit Discontinuous Galerkin Methods For Solving The Relativistic Vlasov-Maxwell System, Pierson Guthrey Jan 2017

Regionally Implicit Discontinuous Galerkin Methods For Solving The Relativistic Vlasov-Maxwell System, Pierson Guthrey

Graduate Theses and Dissertations

The relativistic Vlasov-Maxwell system (RVM) models the behavior of collisionless plasma, where electrons and ions interact via the electromagnetic fields they generate. In the RVM system, electrons could accelerate to significant fractions of the speed of light. An idea that is actively being pursued by several research groups around the globe is to accelerate electrons to relativistic speeds by hitting a plasma with an intense laser beam. As the laser beam passes through the plasma it creates plasma wakes, much like a ship passing through water, which can trap electrons and push them to relativistic speeds. Such setups are known ...


Investigation Of Pyrolysis Gas Chemistry In An Inductively Coupled Plasma Facility, Corey Tillson Jan 2017

Investigation Of Pyrolysis Gas Chemistry In An Inductively Coupled Plasma Facility, Corey Tillson

Graduate College Dissertations and Theses

The pyrolysis mechanics of Phenolic Impregnated Carbon Ablators (PICA) makes it a valued material for use in thermal protection systems for spacecraft atmospheric re-entry. The present study of the interaction of pyrolysis gases and char with plasma gases in the boundary layer over PICA and its substrate, FiberForm, extends previous work on this topic that has been done in the UVM 30 kW Inductively Coupled Plasma (ICP) Torch Facility. Exposure of these material samples separately to argon, nitrogen, oxygen, air, and carbon dioxide plasmas, and combinations of said test gases provides insight into the evolution of the pyrolysis gases as ...


Power And Langmuir Probe Measurements Of H2 Rf Plasma, Alexander A. Stowell May 2016

Power And Langmuir Probe Measurements Of H2 Rf Plasma, Alexander A. Stowell

Macalester Journal of Physics and Astronomy

Methane based gases are often used to produce thin films of biomaterials, such as diamond-like carbon, through Plasma Enhanced Chemical Vapor Deposition. The characterization of the H2 plasma will give a deeper understanding of the physical processes occurring. Understanding these processes could lead to the optimization of the production of these thin films in the future. In this paper, we examine the H2 plasma using a Langmuir probe to gain information on the electron temperature and density of the plasma discharge. We measured electron temperatures of 6eV. Our Langmuir probe data indicates the electron temperature remains constant as ...


Dissociative Excitation Of H2 In An Rf Plasma, John Carlson May 2016

Dissociative Excitation Of H2 In An Rf Plasma, John Carlson

Macalester Journal of Physics and Astronomy

Plasma-enhanced chemical vapor deposition is a widely used method for depositing thin films. In order to optimize the properties of the films, it is important to understand the plasma processes that occur during film growth. In this research we use optical emission spectroscopy in order to measure the spectral emission lines of a plasma produced with hydrogen gas. In conjunction with other measurements and modeling, these measurements can provide insight to the electron energy distribution of the plasma.


Intensity Control Of Dielectric Barrier Discharge Filaments, Matthew Crawford Paliwoda Jan 2016

Intensity Control Of Dielectric Barrier Discharge Filaments, Matthew Crawford Paliwoda

Masters Theses

"When operated in a filamentary mode, a volume dielectric barrier discharge (DBD) is known to produce patterned plasma structures. These structures are currently being explored for reconfigurable metamaterial applications. In this work the presence and intensity of a single filament, within an array of filaments, was controlled by adjusting the voltage to that filament's individual needle electrode. The current, voltage, and time-averaged normalized light intensity were measured while varying the voltage of the needle through a self-biasing resistance. For a 7.5 kV, 3.2 kHz DBD in air, the needle-controlled filament intensity varies from that of the surrounding ...


Improving The Efficiency And Resolution Of Time Of Flight (Tof) Mass Spectrometer For Magnetospheric Applications., Zain Abbas Jan 2016

Improving The Efficiency And Resolution Of Time Of Flight (Tof) Mass Spectrometer For Magnetospheric Applications., Zain Abbas

Honors Theses and Capstones

The Earth magnetosphere is the volume of space formed by the Earth magnetic field in response to the flow of plasma from the solar wind. Although the magnetopause shields us from the solar wind there are far more particles that penetrate with energy, and momentum to the Earths magnetosphere and interacts with the Earth’s magnetic field to create various plasmas and currents which shape and couple different regions of magnetosphere. The study of the dynamics of ions in and outside of the magnetosphere is done through mass spectrometer. Over the years, CODIF Ion TOF spectrometer have been used to ...


Electrically Induced Plasma, Nate Ashby Nov 2015

Electrically Induced Plasma, Nate Ashby

Physics Capstone Projects

My research project, under the mentorship of research professor Ajay Singh was to prove that the plasma he was creating was lasting longer than the electrical current data indicated. He decided that if the plasma was still there, it would be producing light. So we set out to prove that the light emitted from his plasma lasted longer than the current draw measurements.


Kinetic Modeling Of Roll To Roll Rfcvd Plasma, Kudzo S. Ahegbebu, Siva Sashank Tholeti, Alina A. Alexeenko Aug 2015

Kinetic Modeling Of Roll To Roll Rfcvd Plasma, Kudzo S. Ahegbebu, Siva Sashank Tholeti, Alina A. Alexeenko

The Summer Undergraduate Research Fellowship (SURF) Symposium

Roll-to-roll radio frequency plasma enhanced chemical vapor deposition (R2R RFCVD) is a technique for large-scale synthesis of high quality graphitic nanopetals. Graphitic nanopetals are petal-like graphene structures with remarkable electrical and mechanical properties with major industrial applications such as microsupercapacitors. RFCVD uses a non-equilibrium plasma with high energy electrons to catalyze chemical reactions, induce the creation of free radicals, and promote otherwise high temperature chemistry in a low temperature environment. Understanding how bulk plasma characteristics (particularly, power and number densities) vary with changing reactor parameters is an important step towards optimizing synthesis techniques. In our present work we use the ...


Experiments In Flowing And Freely Expanding Dusty Plasmas, John Kenneth Meyer May 2015

Experiments In Flowing And Freely Expanding Dusty Plasmas, John Kenneth Meyer

Theses and Dissertations

I study a dusty plasma produced in a DC glow discharge device. The chamber is a stainless steel cylinder 0.6 m in diameter and 0.9 m long. A stainless steel disk 3.2 cm in diameter acts as the anode and the walls act as the cathode. The discharge current is set between 1 - 10 mA and the voltage at the anode between 250 - 300 V. Dust is initially on a tray beneath the anode, and becomes trapped in the anode glow naturally with high discharge current. A secondary cloud can be made at a different location using ...


Demagnetization Diagnostics In Collisionless Space Plasma Layers, Jershon Ysrael Lopez May 2015

Demagnetization Diagnostics In Collisionless Space Plasma Layers, Jershon Ysrael Lopez

Theses and Dissertations

A recently proposed set of demagnetization diagnostics [Scudder et al., submitted to Physics of Plasmas, 2015] is related to the preconditions of Guiding Center Theory (GCT) and benchmarked in kinetic particle-in-cell simulations. Specifically, GCT requires that the time and length scales of the field are long compared to the Larmor motion of the particles. When this condition is violated, the particles become demagnetized and the assumptions of magnetohydrodynamics are no longer valid. In this thesis, these diagnostics are applied to different space plasma layers of different length scales.

In the past, proxy diagnostics that are not based on fundamental GCT ...