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Cavity Ringdown Spectroscopy In Nitrogen/Oxygen Mixtures In The Presence Of Alpha Radiation, Sidney John Gautrau 2016 University of Southern Mississippi

Cavity Ringdown Spectroscopy In Nitrogen/Oxygen Mixtures In The Presence Of Alpha Radiation, Sidney John Gautrau

Master's Theses

This research was part of an effort to experimentally validate computational models under development for radiation-induced atmospheric effects. Cavity Ringdown Spectroscopy (CRDS) was used to measure the concentration of chemical products generated as a result of radiation interactions in a controlled atmosphere. Experiments were conducted in a vacuum chamber interfaced with a gas introduction system that controlled the initial atmospheric composition. A quadrupole mass spectrometer and tunable dye laser were integrated to confirm initial atmospheric composition, and provide wavelength flexibility for detecting a variety of chemical products generated by radiation interactions. CRDS measurements were made for ozone production resulting from ...


A Measuring Method For Abundance Of Uranium Components Based On Active Source Of Neutron, Li Li, Gen Hu, Keqi Liu 2016 South West University of Science and Technology

A Measuring Method For Abundance Of Uranium Components Based On Active Source Of Neutron, Li Li, Gen Hu, Keqi Liu

The 8th International Conference on Physical and Numerical Simulation of Materials Processing

No abstract provided.


Diffractive Imaging Of Coherent Nuclear Motion In Isolated Molecules, Jie Yang, Markus Guehr, Xiaozhe Shen, Renkai Li, Theodore Vecchione, R. N. Coffee, Jeff Corbett, Alan Fry, Nick Hartmann, Carsten Hast, Kareem Hegazy, Keith Jobe, Igor Makasyuk, Joseph Robinson, Matthew S. Robinson, Sharon Vetter, Stephen Weathersby, Charles Yoneda, Xijie Wang, Martin Centurion 2016 University of Nebraska-Lincoln

Diffractive Imaging Of Coherent Nuclear Motion In Isolated Molecules, Jie Yang, Markus Guehr, Xiaozhe Shen, Renkai Li, Theodore Vecchione, R. N. Coffee, Jeff Corbett, Alan Fry, Nick Hartmann, Carsten Hast, Kareem Hegazy, Keith Jobe, Igor Makasyuk, Joseph Robinson, Matthew S. Robinson, Sharon Vetter, Stephen Weathersby, Charles Yoneda, Xijie Wang, Martin Centurion

Martin Centurion Publications

Observing the motion of the nuclear wave packets during a molecular reaction, in both space and time, is crucial for understanding and controlling the outcome of photoinduced chemical reactions. We have imaged the motion of a vibrational wave packet in isolated iodine molecules using ultrafast electron diffraction with relativistic electrons. The time-varying interatomic distance was measured with a precision 0.07 Å and temporal resolution of 230 fs full width at half maximum. The method is not only sensitive to the position but also the shape of the nuclear wave packet.


Feasibility Of The Use Of Neutron Activation Analysis Techniques In An Underwater Environment, Michael D. Chick 2016 Western Kentucky University

Feasibility Of The Use Of Neutron Activation Analysis Techniques In An Underwater Environment, Michael D. Chick

Masters Theses & Specialist Projects

Elements when bombarded with neutrons emit a gamma ray that is characteristic of the isotope that underwent a neutron induced nuclear reaction; this is known as neutron activation. The characteristic gamma energy of an isotope can then be detected and recorded. One can then analyze the gamma energies captured and determine the elemental makeup of the sample. This form of analysis can be used in an underwater environment making it potentially a valuable tool for agencies tasked with maritime security of ports and waterways, or clean-up operations. This thesis will focus on the feasibility of neutron interrogation using pulsed fast ...


Control Of Spontanous Emission From Quantum Emitters Using Hyperbolic Metamaterial Substrates, Tal Galfsky 2016 The Graduate Center, City University of New York

Control Of Spontanous Emission From Quantum Emitters Using Hyperbolic Metamaterial Substrates, Tal Galfsky

All Graduate Works by Year: Dissertations, Theses, and Capstone Projects

Hyperbolic metamaterials (HMMs) are so named for possessing a hyperboloid-shaped dispersion which gives rise to a large photonic density of states. Quantum emitters placed inside or in the near-field of a HMM have been shown to exhibit strong enhancement of spontaneous emission due to the increase in available states. This thesis focuses on enhancing spontaneous emission of quantum emitters in optical frequencies by utilizing multilayered metal/dielectric composites that form these highly anisotropic metamaterials. In conjunction with the enhanced decay rate we experimentally demonstrate two methods for shaping and directing radiation trapped in the HMM into free space by employing ...


Imaging Population Transfer In Atoms With Ultrafast Electron Pulses, Hua-Chieh Shao, Anthony F. Starace 2016 Purdue University

Imaging Population Transfer In Atoms With Ultrafast Electron Pulses, Hua-Chieh Shao, Anthony F. Starace

Anthony F. Starace Publications

We propose the use of ultrafast electron diffraction (UED) to image a controllable, laser-driven coherent electron population transfer in lithium atoms with currently available femtosecond electron pulses. Our simulations demonstrate the ability of ultrafast electrons to image such an electronic population transfer, thus validating UED as a direct means of investigating electron dynamics. Provided the incident electron pulses have sufficient temporal resolution, the diffraction images are shown to resolve also the relative phases of the target electronic wave functions.


Quantum Cascade Laser Measurements Of Line Intensities, N2-, O2- And Ar- Collisional Broadening Coefficients Of N2o In The L3 Band Near 4.5 Μm, Et-touhami Es-sebbar, Meriem Meriem Deli, Aamir Farooq 2016 Paul Scherrer Institute (PSI)

Quantum Cascade Laser Measurements Of Line Intensities, N2-, O2- And Ar- Collisional Broadening Coefficients Of N2o In The L3 Band Near 4.5 Μm, Et-Touhami Es-Sebbar, Meriem Meriem Deli, Aamir Farooq

Dr. Et-touhami Es-sebbar

This study deals with precise measurements of absolute line intensities, N2-, O2- and Ar- collisional broadening coefficients of N2O in the P-branch of the ν3 vibrational band near 4.5 µm. Collisional broadening coefficients of N2O-air are derived from the N2- and O2- broadening contributions by considering an ideal atmospheric composition. Studies are performed at room temperature for 10 rotational transitions over 2190–2202 cm–1 spectral range using a distributed-feedback quantum cascade laser. To retrieve spectroscopic parameters for each individual transition, measured absorption line shape is simulated within Voigt and Galatry profiles. The obtained results compare well with previous ...


Enhancement Of Hopping Conductivity By Spontaneous Fractal Ordering Of Low-Energy Sites, Tianran Chen, Brian Skinner 2016 West Chester University of Pennsylvania

Enhancement Of Hopping Conductivity By Spontaneous Fractal Ordering Of Low-Energy Sites, Tianran Chen, Brian Skinner

Physics

Variable-range hopping conductivity has long been understood in terms of a canonical prescription for relating the single-particle density of states to the temperature-dependent conductivity. Here we demonstrate that this prescription breaks down in situations where a large and long-ranged random potential develops. In particular, we examine a canonical model of a completely compensated semiconductor, and we show that at low temperatures hopping proceeds along self-organized, low-dimensional subspaces having fractal dimension d = 2. We derive and study numerically the spatial structure of these subspaces, as well as the conductivity and density of states that result from them. One of our prominent ...


Infrared Skin Damage Thresholds From 1319-Nm Continous-Wave Laser Exposures, Gavin D. Buffington, Clifton D. Clark 2016 Fort Hays State University

Infrared Skin Damage Thresholds From 1319-Nm Continous-Wave Laser Exposures, Gavin D. Buffington, Clifton D. Clark

Gavin Buffington

A series of experiments were conducted in vivo using Yucatan miniature pigs (Sus scrofa domestica) to determine thermal damage thresholds to the skin from 1319-nm continuous-wave Nd:YAG laser irradiation. Experiments employed exposure durations of 0.25, 1.0, 2.5, and 10 s and beam diameters of ∼0.6 and 1 cm. Thermal imagery data provided a time-dependent surface temperature response from the laser. A damage endpoint of fifty percent probability of a minimally visible effect was used to determine threshold for damage at 1 and 24 h postexposure. Predicted thermal response and damage thresholds are compared with a ...


Infrared Skin Damage Thresholds From 1319-Nm Continous-Wave Laser Exposures, Gavin D. Buffington, Clifton D. Clark 2016 Fort Hays State University

Infrared Skin Damage Thresholds From 1319-Nm Continous-Wave Laser Exposures, Gavin D. Buffington, Clifton D. Clark

Clifton D. Clark

A series of experiments were conducted in vivo using Yucatan miniature pigs (Sus scrofa domestica) to determine thermal damage thresholds to the skin from 1319-nm continuous-wave Nd:YAG laser irradiation. Experiments employed exposure durations of 0.25, 1.0, 2.5, and 10 s and beam diameters of ∼0.6 and 1 cm. Thermal imagery data provided a time-dependent surface temperature response from the laser. A damage endpoint of fifty percent probability of a minimally visible effect was used to determine threshold for damage at 1 and 24 h postexposure. Predicted thermal response and damage thresholds are compared with a ...


Fractional Charge Methods For Correcting Approximate Kohn-Sham Potentials, Darya N. Komsa 2016 The University of Western Ontario

Fractional Charge Methods For Correcting Approximate Kohn-Sham Potentials, Darya N. Komsa

Electronic Thesis and Dissertation Repository

The Kohn-Sham density functional theory relies on approximating the exchange-correlation energy functional or the corresponding potential. The behavior of the exchange-correlation potential as a function of position in a system can be used to detect and correct deficiencies of the parent functional. The too-fast decay of the potentials derived from common density functionals is a major problem, because it causes inaccurate Rydberg excitation energies and erroneous fractional charges in dissociating molecules. An efficient method to correct the shape of the exchange-correlation potential was proposed by Gaiduk et al. [A. P. Gaiduk, D. S. Firaha, and V. N. Staroverov, Phys. Rev ...


Photonicstd-2d: Modeling Light Scattering In Periodic Multilayer Photonic Structures, Alexey Bondarev, Shaimaa Azzam, Zhaxylyk Kudyshev, Alexander V. Kildishev 2016 North Carolina State University at Raleigh

Photonicstd-2d: Modeling Light Scattering In Periodic Multilayer Photonic Structures, Alexey Bondarev, Shaimaa Azzam, Zhaxylyk Kudyshev, Alexander V. Kildishev

The Summer Undergraduate Research Fellowship (SURF) Symposium

Efficient modeling of electromagnetic processes in optical and plasmonic metamaterials is important for enabling new and exciting ways to manipulate light for advanced applications. In this work, we put together a tool for numerical simulation of propagation of normally incident light through a nanostructured multilayer composite material. The user builds a unit cell of a given material layer-by-layer starting from a substrate up to a superstrate, splitting each layer further into segments. The segments are defined by width and material -- dielectric, metal or active medium. Simulations are performed with the finite difference time domain (FDTD) method. A database of common ...


Hyperpolarized 3he Magnetic Resonance Imaging Phenotypes Of Chronic Obstructive Pulmonary Disease, Damien Pike 2016 The University of Western Ontario

Hyperpolarized 3he Magnetic Resonance Imaging Phenotypes Of Chronic Obstructive Pulmonary Disease, Damien Pike

Electronic Thesis and Dissertation Repository

Chronic obstructive pulmonary disease (COPD) is the third leading cause of death in the world. Identifying clinically relevant COPD phenotypes has the potential to reduce the global burden of COPD by helping to alleviate symptoms, slow disease progression and prevent exacerbation by stratifying patient cohorts and forming targeted treatment plans. In this regard, quantitative pulmonary imaging with hyperpolarized 3He magnetic resonance imaging (MRI) and thoracic computed tomography (CT) have emerged as ways to identify and measure biomarkers of lung structure and function. 3He MRI may be used as a tool to probe both functional and structural properties of the lung ...


Observations Of High Vibrational Levels Of The 4fσ 41Σ+ U State Of H2, Alexander M. Chartrand, Robert C. Ekey Jr., Elizabeth F. McCormack 2016 Bryn Mawr College

Observations Of High Vibrational Levels Of The 4fσ 41Σ+ U State Of H2, Alexander M. Chartrand, Robert C. Ekey Jr., Elizabeth F. Mccormack

Physics Faculty Research and Scholarship

Resonantly enhanced multiphoton ionization via the EF 1Σg+, v′ = 6 double-well state has been used to probe the energy region below the third dissociation limit of H2 where several high vibrational levels of the 41Σu+ state are expected. Theoretical ab initio potential energy curves for this state predict a deep inner well and shallow outer well where vibrational levels above v = 8 are expected to exhibit the double-well character of the state. Since the 41Σu+ state has f-state character, transitions to it from the ground state are nominally forbidden. However ...


Multistart Spiral Electron Vortices In Ionization By Circularly Polarized Uv Pulses, Jean Marcel Ngoko Djiokap, Alexei V. Meremianin, N. L. Manakov, S. X. Hu, L. B. Madsen, Anthony F. Starace 2016 University of Nebraska-Lincoln

Multistart Spiral Electron Vortices In Ionization By Circularly Polarized Uv Pulses, Jean Marcel Ngoko Djiokap, Alexei V. Meremianin, N. L. Manakov, S. X. Hu, L. B. Madsen, Anthony F. Starace

Anthony F. Starace Publications

Multistart spiral vortex patterns are predicted for the electron momentum distributions in the polarization plane following ionization of the helium atom by two time-delayed circularly polarized ultrashort laser pulses. For two ultraviolet (UV) pulses having the same frequency (such that two photons are required for ionization), single-color two-photon interferometry with corotating or counter-rotating time-delayed pulses is found to lead respectively to zero-start or four-start spiral vortex patterns in the ionized electron momentum distributions in the polarization plane. In contrast, two-color one-photon plus two-photon interferometry with time-delayed corotating or counter-rotating UV pulses is found to lead respectively to one ...


Spica: Stereographic Projection For Interactive Crystallographic Analysis, X. Z. (Xingzhong) Li 2016 University of Nebraska-Lincoln

Spica: Stereographic Projection For Interactive Crystallographic Analysis, X. Z. (Xingzhong) Li

Faculty Publications from Nebraska Center for Materials and Nanoscience

In numerous research fields, especially the applications of electron and X-ray diffraction, stereographic projection represents a powerful tool for researchers. SPICA is a new computer program for stereographic projection in interactive crystallographic analysis, which inherits features from the previous JECP/SP and includes more functions for extensive crystallographic analysis. SPICA provides fully interactive options for users to plot stereograms of crystal directions and crystal planes, traces, and Kikuchi maps for an arbitrary crystal structure; it can be used to explore the orientation relationships between two crystalline phases with a composite stereogram; it is also used to predict the tilt angles ...


Emergence Of Collective Light Scattering In Atomic 87rb Samples, Kasie Jean Kemp 2016 Old Dominion University

Emergence Of Collective Light Scattering In Atomic 87rb Samples, Kasie Jean Kemp

Physics Theses & Dissertations

Over the past half century, atomic ensembles have been used to create sensors, clocks, and quantum information systems. As these devices become more compact, and as the number of atoms increases to improve the sensitivity for detection, the atomic samples are increasing in density and optical depth. As such, the spectroscopic properties of the atomic media are modified due to interactions among the particles in the ensemble. We report investigation of near-resonance light scattering from a cold atomic sample of 87Rb. Initially prepared in a magneto-optical trap, the atoms are loaded into a far-off-resonance optical dipole trap (FORT) in which ...


A Chemical Kinetic Study Of The Reaction Of Hydroxyl With Furans, Et-touhami Es-sebbar, Ahmed Elwardany, K. Fethi, A. Farooq 2016 KAUST

A Chemical Kinetic Study Of The Reaction Of Hydroxyl With Furans, Et-Touhami Es-Sebbar, Ahmed Elwardany, K. Fethi, A. Farooq

Dr. Et-touhami Es-sebbar

Furans, a class of cyclic ethers, are potential renewable fuels and additives to conventional fuels. High temperature oxidation of furans is dominated by their reaction with hydroxyl radical. In this work, rate coefficients for the reaction of hydroxyl (OH) with furan (k1), 2-methyl furan (k2) and 2,5-dimethyl furan (k3) were measured behind reflected shock waves over a temperature range of 890–1388 K and pressures of 1–2 atm. Hydroxyl radicals were generated via the thermal decomposition of tert-butylhydroperoxide.

The OH radicals were monitored using the well-characterized R1(5) rotational line of the A–X (0, 0) band in ...


Theoretical Analysis Of Single Molecule Spectroscopy Lineshapes Of Conjugated Polymers, Murali Devi 2016 Graduate Center, City University of New York

Theoretical Analysis Of Single Molecule Spectroscopy Lineshapes Of Conjugated Polymers, Murali Devi

All Graduate Works by Year: Dissertations, Theses, and Capstone Projects

Conjugated Polymers(CPs) exhibit a wide range of highly tunable optical properties. Quantitative and detailed understanding of the nature of excitons responsible for such a rich optical behavior has significant implications for better utilization of CPs for more efficient plastic solar cells and other novel optoelectronic devices. In general, samples of CPs are plagued with substantial inhomogeneous broadening due to various sources of disorder. Single molecule emission spectroscopy (SMES) offers a unique opportunity to investigate the energetics and dynamics of excitons and their interactions with phonon modes. The major subject of the present thesis is to analyze and understand room ...


Model For The Electrolysis Of Water And Its Use For Optimization, Roger Lascorz, Javier E. Hasbun Dr 2016 Georgia Institute of Technology

Model For The Electrolysis Of Water And Its Use For Optimization, Roger Lascorz, Javier E. Hasbun Dr

Georgia Journal of Science

The goal of this research was to study the optimization of the electrolysis of water both theoretically and experimentally. For accuracy, 3 hr experiments were made with measurements recorded every 15 min. The results show that a better model than the classical one is needed for water electrolysis. A new model that fits experimental data better is proposed. The results of this new model not only predict hydrogen production in electrolysis of water better, but show a way to predict gas production of any liquid as well as what voltage to use to optimize it.


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