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- Alloy 800; Fe-Cr-Ni Alloy; Metal Oxides; Oxide Film Formation; Metal Dissolution; Interfacial Reactions; Electrochemical Reactions; Water Radiolysis; gamma-Radiation; Steady-state radiolysis; (1)
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Articles 1 - 15 of 15
Full-Text Articles in Physics
Analysis Of Primary Stripper Foils At The Spallation Neutron Source By An Electron Beam Foil Test Stand, Eric Paul Barrowclough
Analysis Of Primary Stripper Foils At The Spallation Neutron Source By An Electron Beam Foil Test Stand, Eric Paul Barrowclough
Doctoral Dissertations
Diamond films are used at the Spallation Neutron Source (SNS) as the primary charge exchange foils (i.e., stripper foils) of the accelerated 1 GeV (Gigaelectron volts) hydride ions. The most common type of film used is a nanocrystalline diamond film, typically 17 mm x 45 mm (millimeter) with an aerial density of 350 μg/cm2 (microgram per square centimeter). The diamond film is deposited on a corrugated silicon substrate using plasma-assisted chemical vapor deposition. After the growth of the diamond film, 30 mm of the silicon substrate is etched away, leaving a freestanding diamond foil with a silicon handle that …
Artificial Olfactory System For Multi-Component Analysis Of Gas Mixtures., Alexander Aleksandrovich Larin
Artificial Olfactory System For Multi-Component Analysis Of Gas Mixtures., Alexander Aleksandrovich Larin
Electronic Theses and Dissertations
Gas analysis is an important part of our world and gas sensing technology is becoming more essential for various aspects of our life. A novel approach for gas mixture analysis by using portable gas chromatography in combination with an array of highly integrated and selective metal oxide (MOX) sensors has been studied. We developed a system with small size (7 x 13 x 16 inches), low power consumption (~10 W) and absence of special carrier gases designed for portable field analysis (assuming apriori calibration). Low ppb and even sub-ppb level of detection for some VOCs was achieved during the analysis …
Gamma-Radiation Induced Corrosion Of Alloy 800, Mojtaba Momeni
Gamma-Radiation Induced Corrosion Of Alloy 800, Mojtaba Momeni
Electronic Thesis and Dissertation Repository
This thesis presents a newly developed mechanism and predictive model for the corrosion of Alloy 800. The Fe-Cr-Ni Alloy (Incoloy 800) is mainly used for steam generator (SG) tubing in CANDU and PWR reactors and is a candidate material for the proposed Canadian Supercritical Water Reactor (SCWR) in which it will be exposed to extreme conditions of high radiation flux and large temperature gradients. The influence of gamma radiation and water chemistry conditions on the corrosion behaviour of Alloy 800 are studied in this work. Ionizing radiation creates reducing (•eaq–, •H, •O2-) and oxidizing …
Construction And Analysis Of Accurate Exchange-Correlation Potentials, Sviataslau V. Kohut
Construction And Analysis Of Accurate Exchange-Correlation Potentials, Sviataslau V. Kohut
Electronic Thesis and Dissertation Repository
Practical Kohn–Sham density-functional calculations require approximations to the exchange-correlation energy functional, EXC[ρ], or the exchange-correlation potential, vXC(r), defined as the functional derivative of EXC[ρ] with respect to the electron density, ρ. This thesis focuses on the following problems: (i) development of approximate exchange-correlation potentials by modelling the exchange-correlation charge distribution; (ii) accurate approximation of functional derivatives of orbital-dependent functionals; (iii) generation of exchange-correlation potentials from many-electron wavefunctions; (iv) analysis of accurate exchange-correlation potentials in atoms and molecules.
The advantage of modelling the exchange-correlation potential through the exchange-correlation …
Electronic And Magnetic Materials Under External Stimuli, Kenneth Robert O'Neal
Electronic And Magnetic Materials Under External Stimuli, Kenneth Robert O'Neal
Doctoral Dissertations
The interaction between spin, charge, and lattice degrees of freedom leads to exotic and useful properties in multifunctional materials. This delicate balance of energy scales allows external stimuli such as temperature, magnetic field, or pressure to drive to novel phases. As a local probe technique, spectroscopy can provide insight into the microscopic mechanism of the phase transitions. In this dissertation I present spectroscopic studies of functional materials under extreme conditions.
Nanomaterials have attracted attention because nanoscale confinement affects various material properties and often reduces energy scales or suppress phase transitions. Combining Raman and infrared spectroscopies reveals that the breakdown mechanism …
Functional And Structural Studies Of Cytochromes P450 By Resonance Raman Spectroscopy, Yilin Liu
Functional And Structural Studies Of Cytochromes P450 By Resonance Raman Spectroscopy, Yilin Liu
Dissertations (1934 -)
Cytochrome P450 is a broad class of heme monooxygenase enzymes which catalyze various oxidative transformations. There are two main kinds of mammalian P450s: steroidogenic and drug metabolizing P450s. The first project involves a steroidogenic P450, CYP17A1, occupying a central role in the biosynthesis of steroid hormones. It catalyzes hydroxylation reaction on pregnenolone and progesterone, generating 17OH-pregnenolone and 17OH-progesterone, presumably utilizing a “Compound I” species. However, these hydroxylated products can be further processed in a second oxidative cycle to cleave the C17–C20 bond to form dehydroepiandrosterone or androstenedione, respectively, a crucial step in androgen production. Interestingly, it is well known that …
Nuclear Spin Alignment In Optically Pumped Semiconductors, Matthew M. Willmering
Nuclear Spin Alignment In Optically Pumped Semiconductors, Matthew M. Willmering
Arts & Sciences Electronic Theses and Dissertations
Nuclear magnetic resonance (NMR) has shown its ability to be a very informative analytical technique due to the ability to measure very small changes in the energy splittings due to the nuclei’s local environment. However, this ability is hindered by the low sensitivity of the experiment. Many methods have been postulated and implemented to enhance the sensitivity of NMR experiments; one of which is optically pumped NMR (OPNMR). In this dissertation, the usefulness and potential applications of OPNMR are presented. First, a doubly resonant OPNMR probe was fabricated in order to complete more advanced NMR techniques while optically pumping the …
Universal Disorder In Organic Semiconductors Due To Fluctuations In Space Charge, Tzucheng Wu
Universal Disorder In Organic Semiconductors Due To Fluctuations In Space Charge, Tzucheng Wu
Physics & Astronomy ETDs
This thesis concerns the study of charge transport in organic semiconductors. These materials are widely used as thin-film photoconductors in copiers and laser printers, and for their electroluminescent properties in organic light-emitting diodes. Much contemporary research is directed towards improving the efficiency of organic photovoltaic devices, which is limited to a large extent by the spatial and energetic disorder that hinders the charge mobility. One contribution to energetic disorder arises from the strong Coulomb interactions between injected charges with one another, but to date this has been largely ignored. We present a mean-field model for the effect of mutual interactions …
Understanding Three-Body Interactions In Hexagonal Close Packed Solid He-4, Ashleigh Locke Barnes
Understanding Three-Body Interactions In Hexagonal Close Packed Solid He-4, Ashleigh Locke Barnes
Doctoral Dissertations
The ground state properties of hexagonal close packed (hcp) solid 4He [He-4] are dominated by large atomic zero point motions which make the primary contribution to the solid’s low-temperature Debye-Waller (DW) factors. Preliminary investigations have also suggested that three-body interactions can play an important role in this system, particularly at higher densities. However, due to their computational cost, these interactions are not generally incorporated into theoretical models of solid 4He [He-4]. In order to accurately treat both zero point motion and three-body interactions, we have developed a perturbative treatment in which the three-body energy is added as a …
Investigating The Properties Of Superfluid He-4 Through Density Functional Calculations, Matthew Francis Dutra
Investigating The Properties Of Superfluid He-4 Through Density Functional Calculations, Matthew Francis Dutra
Doctoral Dissertations
We present a study of isotopically pure He-4 systems evaluated using helium density functional theory (He-DFT) with the intent of better understanding their ground state structural and energetic properties, particularly within the scope of singularly-doped helium droplets. We self-consistently solve for the density profiles and chemical potentials for a wide range of pure helium droplet sizes (up to 9500 atoms) via an imaginary time propagation method, and fit the resultant energetic data to a power law formula to be able to extrapolate values for even larger droplets. Subsequent calculations on singularly-doped droplets within the same size range yield accurate binding …
An Ab Initio Study Of Bonding In The Ag-Clpx3 Complex (For X = H, F), Michael Ryan
An Ab Initio Study Of Bonding In The Ag-Clpx3 Complex (For X = H, F), Michael Ryan
HON499 projects
Quantum Theory of Atoms in Molecules (QTAIM) and Natural Bond Orbital (NBO) analyses were performed on AgCl-PX3 complexes, where X = H, F. The analyses indicate the presence of a 3- center- 4- electron (3c4e) hyperbond between the Cl, Ag, and P atoms, formed by a charge transfer from the occupied p orbital of the phosphorus and Lowest Unoccupied Molecular Orbital (LUMO), (nominally a σ*.). Delocalization of the complexes’ electrons results from these interactions. Furthermore, the complexes were bound predominately by electrostatic interactions (approximately 80%), as opposed to covalent bonds. The structures are resonance stabilized with the Cl-Ag and Ag-P …
Investigations Into Structure And Properties Of Atomically-Precise Transition Metal-Chalcogenide Clusters Of Crte And Ligated Cr6te8(Pet3)6, Anthony F. Pedicini
Investigations Into Structure And Properties Of Atomically-Precise Transition Metal-Chalcogenide Clusters Of Crte And Ligated Cr6te8(Pet3)6, Anthony F. Pedicini
Theses and Dissertations
The complete understanding of a clusters electronic structure, the primary mechanisms for its properties and stabilization is necessary in order to functionalize them for use as building blocks within novel materials. First principle theoretical studies have been carried out upon the electronic properties of CrxTey (x = 1 – 6, y = 0 – 8, x + y ≤ 14), as well as for the larger triethylphosphine (PEt3) ligated cluster system of Cr6Te8(PEt3)6. Together, we aim to use the information garnered from the smaller clusters to address …
Using Low-Coherence Interferometry To Monitor Cell Invasion In An In-Vitro Model System, Behnaz Davoudi Nasab
Using Low-Coherence Interferometry To Monitor Cell Invasion In An In-Vitro Model System, Behnaz Davoudi Nasab
Honors Undergraduate Theses
In an optically random system, such as naturally occurring and man-made media, light undergoes pronounced multiple scattering. This phenomenon has shown a remarkable potential in characterizing complex materials. In this regime, scattering occurs from each individual center of the scattering and independent scattering events lead to multiple light scattering. This phenomenon is often described as a random walk of photons and can be modeled in terms of a diffusion equation based on the radiative transfer theory. In this thesis, we used optical path-length spectroscopy (OPS), which is an experimental method to obtain the path-length probability density of the propagating light …
Attosecond Spectroscopy Probing Electron Correlation Dynamics, Alexander Heinecke Winney
Attosecond Spectroscopy Probing Electron Correlation Dynamics, Alexander Heinecke Winney
Wayne State University Dissertations
Electrons are the driving force behind every chemical reaction. The exchange, ionization, or even relaxation of electrons is behind every bond broken or formed. According to the Bohr model of the atom, it takes an electron 150 as to orbit a proton[6]. With this as a unit time scale for an electron, it is clear that a pulse duration of several femtoseconds will not be sufficient to understanding electron dynamics. Our work demonstrates both technical and scientific achievements that push the boundaries of attosecond dynamics. TDSE studies show that amplification the yield of high harmonic generation (HHG) may be possible …
Design And Activation Of Frequency Tunable 200ghz Gyrotron, Natalie Golota, Faith Scott, Edward Saliba, Brice Albert, Alexander Barnes
Design And Activation Of Frequency Tunable 200ghz Gyrotron, Natalie Golota, Faith Scott, Edward Saliba, Brice Albert, Alexander Barnes
Undergraduate Research Symposium Posters
Dynamic Nuclear Polarization (DNP) when combined with Nuclear Magnetic Resonance (NMR) yields high sensitivity spectra while decreasing sample acquisition time. DNP transfers polarization from electron to nuclear spins, giving a strong enhancement of NMR signal. DNP is rapidly developing area of research due in part to application of cyclotron resonance masers (gyrotron) as high power microwave sources. Gyrotrons provide a high-power, high-frequency microwave source that can be used in close proximity to high field NMR magnets. Gyrotrons are operated under strong vacuum and within a cryogenic superconducting magnetic. Gyrotron microwave power is generated by a magnetron injection gun (MIG) composed …