Physical Sciences and Mathematics Commons^™

Observational Constraints On The 520 Km Mantle Discontinuity, Mantle Transition Zone Anisotropy, And Local Seismicity At Mount St. Helens, Han Zhang

Earth and Planetary Sciences ETDs

Seismology provides valuable observational constraints to thermal and compositional states at inaccessible depths via understanding how elastic wave propagating through them. While many of fundament questions regarding solid Earth structures have been addressed during its more than 100 years history, some details remain unfilled and carefully designed approaches are needed to complete the pictures. This dissertation contributes observational constraints on three topics with newly developed methods. 1) We detected a controversial mantle discontinuity at about 520 km and concluded a mean mantle composition close to the Pyrolite model based on its seismic properties. 2) We isolated anisotropic effects in mantle …

Exploring Tunable Magnetization And High-Temperature Ferromagnetism In Ternary Transition Metal-Based Chalcogenides, Hector Iturriaga

Open Access Theses & Dissertations

The discovery of long-range magnetic ordering in ultrathin transition metal-based compounds shows great promise for the development of nanoscale memory and spintronic devices. Composed of cost-effective materials and boasting from strong chemical and thermal stability at low dimensions, van der Waals (vdW) ternary transition metal chalcogenide magnets like CrSiTe3 (CST), Fe2.7GeTe2 (FGT), and Mn3Si2Te6 (MST), provide not only possible energy solutions, but also a broad platform to explore the versatile magnetic character of this family of compounds. Although they have great potential, it has been found that their long-range magnetic ordering exists at temperatures far too low (the highest of …

Non-Adiabatic Perturbations And Non-Gaussianity During Inflation: Affine Gravity Approach, Isaac Bamwidhi

Theses

This thesis is concerned with providing a complete study of non-Gaussianity and entropy perturbations that are sourced by multiple fields nonminimally coupled to gravity. The study will be performed in the framework of the two important formulations of gravity, namely: purely metric (general relativity) and purely affine formulation – where the metrical structure results from the dynamics of the spacetime affine connection. We shall employ a covariant formalism in our framework and demonstrate that it leads to a curved field space which can produce a conspicuous departure from the purely metric gravity. This work is expected, not only to derive …

Calculated Charge State Distributions And Anisotropies Following The Β-Decay Of 6he, Eva E. Sculhoff

Electronic Theses and Dissertations

According to the standard model the beta-decay of 6He is a pure Gamow-Teller transition. The aim of this thesis is to provide theoretical support in the search for new physics beyond the standard model by examining the angular distribution of beta particles following decay. The simple structure of 6He, along with its ability to under go beta-decay into 6Li+ makes it an ideal candidate for studying the weak force. Due to the sudden increase in nuclear charge from Z = 2 to Z = 3, and the recoil momentum of the daughter nucleus resulting from the emitted leptons, this decay …

Bedrock Anisotropy At Sycamore Farms: An Investigation Using Azimuthal Resistivity And Electromagnetic Induction, Cody M. Kessler

Browse all Theses and Dissertations

Azimuthal resistivity surveys coupled with an electromagnetic survey were completed at Sycamore Farms with the goal of investigating bedrock fracturing at the site. Previous work on this subject matter was completed at the site using similar geophysical tools, however, this study utilizes a unique method of azimuthal resistivity and higher resolution electromagnetic data. 72 azimuthal surveys were completed, and the electromagnetic survey covered all fields in which azimuthal surveys were completed. The results from the two methods were compared to identify zones of bedrock fracturing. Although correlation between the two data sets was limited it was found that the electromagnetic …

Total Internal Reflection: Applications In Nonlinear Microscopy And Fluorescence Anisotropy, Brandon Colon

Doctoral Dissertations

As technology advances to harness new energies and to create new cures, the sophistication of analysis grows not only in depth but in efficiency. Total internal reflection (TIR) has been coupled to microscopy leveraging its unique optical phenomenon on a breadth of topics. In this dissertation, the work presented will show how TIR was applied in two different instrumental analyses to evaluate two unique and complex systems. The first project features TIR paired with the transient absorption microscopy (TAM), a nonlinear optical technique, to gauge solvent mixing and diffusion in microreactors. Microreactors gained acclaim for their ability to produce high …

The Return To Anisotropy Across A Jet In Crossflow, Gregory P. Sakradse

Dissertations and Theses

With data from experiments on a jet of air emitting from an orifice flush with the floor of a wind tunnel providing a transverse flow, analysis is conducted to extract information about the state of anisotropy in the Reynolds stress tensor. Inflow velocities are modulated across two distinct turbulence intensity regimes while holding jet exit conditions constant, providing an opportunity to isolate effects of both jet to crossflow velocity ratio, r and the effects of the turbulence carried by the crossflow. Anisotropy in the Reynolds stress tensor is examined through anisotropy invariant maps and evolution of the function F, …

Modeling Hydraulic Fracturing Initiation And Propagation In Porous Rock Formationsl, Chang Huang

LSU Doctoral Dissertations

Hydraulic fracturing has long been introduced to the oil and gas industry since the early nineteenth century for both reservoir characterization and reservoir stimulation. Despite the progress made in the last two decades, many challenges still have not been tackled regarding not only the propagation problem but also the initiation problem due to its complexity. The dissertation is divided into two stages, i.e., before and after fracture initiation. The first stage of the research aimed at improving the accuracy in solving the poro-mechanical response of wellbore during fluid injection before a tensile fracture occurs, which is crucial to determine the …

Understanding The Role Of Anisotropy On The Optoelectronic And Colloidal Properties Of Quantum Rods For Programmable Self-Assembly With Dna Origami, Yuetian Chen

Dissertations - ALL

Semiconductor nanocrystals, like quantum dots (QDs) and quantum rods (QRs), have tunable optoelectronic properties that depend on their composition, size and asymmetry. A small change in size or aspect ratio can lead to measurable changes in optical absorption and photoluminescence emission energies, as well as varied degrees of polarized optical behaviors at those energies. My dissertation research focuses on investigating the role of anisotropy on the optoelectronic and colloidal properties of quantum rods, as well as using DNA-mediated self-assembly to align these quantum rods on DNA origami for energy transfer applications in biocompatible systems. First, CdSe of systematically varied aspect …

Numerical Simulations Of Complex Crater Formation In Layered And Mixed Targets, Ryan Hopkins

Electronic Thesis and Dissertation Repository

Numerical simulations of hypervelocity impact events provide a unique method of analyzing the mechanics that govern impact crater formation. This thesis describes modifications that were made to the impact Simplified Arbitrary Lagrangian Eulerian (iSALE) shock-physics code in order to more accurately simulate meteorite impacts into layered target sequences and details several applications that were investigated using this improved strength model.

Meteorite impacts occur frequently in layered targets but resolving thin layers in the target sequence is computationally expensive and therefore not often considered in numerical simulations. To address this limitation iSALE was modified to include an anisotropic yield criterion and …

Fault Mapping In 3d Seismic Reflection Data Using Seismic Attributes And Velocity Anisotropy: Example From West Virginia, Megan Valdez

Graduate Theses & Non-Theses

Fracture characterization is highly important in the oil and gas industry. Knowing the location of fractures allows for the assessment of reservoir quality, aids in well placement and planning, and helps identify locations of possible traps. Fracture locations can be determined using seismic data for attribute calculations and anisotropy analysis. Attribute calculations, such as coherence and curvature, identify subtle changes in the dataset that conventional seismic data interpretation might overlook. Anisotropy analysis looks at directionally dependent variations in the wave propagation velocity. Fractures slow the propagation velocity of a wave if the fractures are perpendicular to the wave direction. A …

Oleic Acid Vesicles: Formation, Mechanisms Of Reactivity, And Uses In Determination Of Terpene Activity, Laura A. Walther

Theses and Dissertations--Chemistry

This dissertation will focus on the volatile compounds released upon the burning of incense which are numerous and varied. The first part of this dissertation is the gas chromatography-mass spectral (GC-MS) analysis of burning incense collected via solid phase microextraction (SPME) with the aim of developing a library of compounds found in incense as used in the Orthodox church.

The second part of this dissertation has the aim of developing a method for forming oleic acid bilayer vesicle membranes and a fluorescence spectroscopy method by which the reactivities of these vesicles can be analyzed. These reactivities include permeability, fluidity, aggregation, …

Application Of Seismic Radial Anisotropy For Near-Surface Fractures Identification, Jer-Yu Jeng

Dissertations, Master's Theses and Master's Reports

Fractures significantly control the groundwater flow and solute transport in geological settings of low-permeable rocks. Fractures also affect seismic wave propagation. For instance, they can create a directional dependence of seismic velocity with respect to their orientations, known as seismic anisotropy. Seismic radial anisotropy as used here is the difference between the velocity of a vertically polarized S-wave (SV) and one polarized horizontally (SH). In this thesis, seismic radial anisotropy was used to evaluate its usefulness for correlating with near-surface fractures. The seismic radial anisotropy models were obtained at two sites from dispersion analyses of the Rayleigh waves, with vertical …

Seismic Refraction And Electrical Resistivity Tests For Fracture Induced Anisotropy In A Mountain Watershed, Aida Mendieta

Boise State University Theses and Dissertations

The critical zone (CZ) is the earth’s layer where water, air, rock, and life meet. It is the zone with which humans interact most. The National Research council (2001) defines the CZ as a “heterogeneous, near surface environment in which complex interactions involving rock, soil, water, air, and living organisms regulate the natural habitat and determine the availability of life sustaining resources”. The CZ may extend roughly from the top of the vegetation canopy to the deepest part of the rock column where meteoric water circulates – this is often in the 10 – 30 m range. The upper 1-2 …

Petrophysical Investigations Of The Marathon Cu-Pge Deposit, Marathon, On, Hiruni Gunawardana

Electronic Thesis and Dissertation Repository

Drill core samples obtained from four mineralized zones of the Marathon Cu-PGE deposit in the Coldwell igneous complex have been investigated for their petrophysical characteristics. Remanent magnetization was used as a possible tool to reorient core samples but a drilling induced overprint magnetization dominated the record. Anisotropy of magnetic susceptibility was measured to provide a proxy for the petrofabric of samples obtained from oriented drill cores; a well-defined planar fabric was found to strike 177 and dip 25°W, with down-dip lineation, in excellent agreement with inferred magmatic flow direction based on 3D modeling of mineralized footwall troughs. Magnetite rich lithologies …

Soil Moduli Obtained From A Back Pressure Constant Rate Of Strain Bender Element Consolidation Apparatus, Yi Zhao

Graduate Theses and Dissertations

A back-pressure saturated, constant-rate-of-strain consolidation device was modified to incorporate bender elements (BP-CRS-BE) and thus allowed for shear wave measurements during consolidation tests. This newly fabricated system has many advantages over other previous or current devices: 1) it can be utilized not only for laboratory prepared soil samples but also for field sampled soils such as Shelby tube samples, and 2) continuous compression curves, and continuous values of vertical hydraulic conductivity and coefficient of consolidation can be acquired with a significant reduction in testing time. Soil modulus values such as shear modulus and constrained modulus are also able to be …

Optical Characterization Of Anisotropic Interfaces, Renjie Hou

Electronic Thesis and Dissertation Repository

The understanding of optical properties of surfaces and interfaces are critical for the development of new technologies ranging from photonics to molecular electronics. Knowing for example the orientation of molecules functionalized onto a surface yields valuable information about the macroscopic properties of the resulting surface. The optical properties can be tuned using various strategies such as molecular functionalization or patterning of meta-structures that ultimately interact with light in a rational way. Advanced optical and spectroscopy methods allowing one to probe such surfaces are therefore key to correlate properties and surface functionalization.

In this thesis, multiple approaches have been taken to …

An Improved Tight-Binding Model For Phosphorene, Kursti Delello

Honors Undergraduate Theses

The intent of this thesis is to improve upon previously proposed tight-binding models for one dimensional black phosphorus, or phosphorene. Previous models offer only a qualitative analysis of the band structure of phosphorene, and fail to fully realize critical elements in the electronic band structure necessary for transport calculations. In this work we propose an improved tight-binding model for phosphorene by including up to eight nearest-neighbor interactions. The efficacy of the model is verified by comparison with DFT-HSE06 calculations, and the anisotropy of the effective masses in the armchair and zigzag directions is considered.

Seismic Anisotropy And Mantle Dynamics Beneath The Central And Western United States, Bin Yang

Doctoral Dissertations

"Various tectonic features and the recent availability of high-quality broadband seismic data from the USArray and other seismic stations in the central and western United States (CWUS) provide a distinct opportunity to test different anisotropy-forming mechanisms. For the first part of the study, a total of 4138 pairs of well-defined shear wave splitting (SWS) parameters observed at 445 stations on the northern Great Plains show systematic spatial variations of anisotropic characteristics. Azimuthally invariant fast orientations subparallel to the absolute plate motion (APM) direction are observed at most of the stations on the Superior Craton and the southern Yavapai province, indicating …

Azimuthal Anisotropy Beneath North Central Africa From Shear Wave Splitting Analysis, Awad Abdussalam Henish Lemnifi

Doctoral Dissertations

"This study represents the first multi-station investigation of azimuthal anisotropy beneath the interior of north central Africa, including Libya and adjacent regions, using shear wave splitting (SWS) analysis. Data used in the study include recently available broadband seismic data obtained from 15 stations managed by the Libyan Center for Remote Sensing and Space Science, and those from five other stations at which data are publicly accessible. A total of 583 pairs of high-quality SWS measurements utilizing the PKS, SKKS, and SKS phases demonstrate primarily N-S fast orientations with an average splitting delay time of approximately 1.2 s. An absence of …

Mechanical Characteristics Of Organically Modified Fly Ash-Kaolinite Mixtures, Xin Kang

Doctoral Dissertations

"Fly ash is a hazardous waste material to the environment. Beneficial reuse of fly ash, however, brings economic and environmental benefits, i.e., decreases the cost of disposal, reduces greenhouse gas emission, and improves mechanical properties of construction materials. Due to the lack of pozzolanic properties, the reuse rate of Class F fly ash in geotechnical engineering is relatively low (ACAA 2013). In order to promote the effectiveness and sustainability of high volume reuse of class F fly ash in geotechnical engineering, biopolymers (Chitosan, and Xanthan gum) and synthetic polymers (Polyethylene Oxide, PEO) were used instead of the traditional stabilizers to …

Magneto-Optical Kerr Eect Study Of Magnetic Anisotropy In Soft Ferromagnets, Tatiana Marie Eggers

USF Tampa Graduate Theses and Dissertations

The continued progress of modern information technology relies on understanding the influence of magnetic anisotropy on magnetic thin films. In this work, two sources of magnetic anisotropy are examined in two different soft ferromagnets: a uniaxial anisotropy induced during the fabrication of Ni₈₀Fe₂₀ and exchange anisotropy, or exchange bias, which occurs at the interface of Ni₇₇Fe₁₄Cu₅Mo₄/Fe₅₀Mn₅₀ bilayer. A home-built Magneto-optical Kerr effect magnetometer is used to measure the magnetic response of the soft ferromagnetic films and details of its construction are also discussed. A simple model …

Targeted Full-Waveform Inversion For Recovering Thin- And Ultra-Thin-Layer Properties Using Radar And Seismic Reflection Methods, Esther Babcock

Boise State University Theses and Dissertations

Ground penetrating radar (GPR) and seismic reflection methods are useful geophysical tools for near-surface characterization. Analysis of radar or seismic reflection data can combine velocity analysis with common physical transformations to provide subsurface physical properties such as subsurface porosity, density, and contaminant locations. However, reliable quantitative characterization of thin subsurface layers may be impossible using standard reflection data processing techniques, e.g. velocity analysis, if the layer thickness is below the conventional resolution limits of the data. The limiting layer thickness for layer resolution may be up to ½ or even ¾ of the dominant wavelength (λ) of the …

The Effect Of Single Crystal Elastic And Plastic Anisotropy On Stress And Strain Heterogeneity: Comparison Of Olivine To Other Common Minerals, Christopher Joseph Cline Ii

UNLV Theses, Dissertations, Professional Papers, and Capstones

In order to investigate the influence of single crystal elastic anisotropy on the heterogeneity of stress distributions during polycrystalline deformation multiple deformed crystalline materials were analyzed using electron backscatter diffraction (EBSD). Deformation experiments were conducted on samples of Solnhofen limestone using a modified Griggs piston cylinder apparatus at UNLV, and also on San Carlos olivine using the D-DIA multi-anvil press at the National Synchrotron Light Source beamline X17B2. Analysis of the mechanical twins in deformed calcite and kink bands in olivine help elucidate deviations in local stress directions away from that of the applied macroscopic stress. Combined calculated compression directions …

Characterization Of Heterogeneous Media With Multicomponent Laser Ultrasonics, Thomas E. Blum

Boise State University Theses and Dissertations

Wave propagation in scattering media is a complicated topic, but scattered elastic waves carry important information about the internal structure of the medium. It is a current topic of research and for the foreseeable future. Advances in theory and applications described in this manuscript benefit from new ways to collect more densely sampled, multicomponent, true-amplitude data.

Thus far, most fracture characterization experiments in the laboratory involve contacting transducers as elastic wave sources and receivers. Similarly, rock properties such as anisotropy and attenuation are also measured with contacting techniques. These type of measurements are well-suited for time-of-flight measurements, but for scattering …

Multimessenger Approach To Search For Cosmic Ray Anisotropies, Larry David Buroker

Theses and Dissertations

The origin of the highest energy cosmic rays is still unknown. The discovery of their sources will reveal the workings of the most energetic astrophysical accelerators in the universe. Recent international efforts have brought us closer to unveiling this mystery. Possible ultra-high energy cosmic ray sources have been narrowed down with the confirmation of an "ankle" and the GZKlike spectral feature at the high-end of the energy spectrum. A clear resolution of the ultra-high energy mystery calls for the search of anisotropies in the distribution of arrival directions of cosmic rays. In this thesis, we adopt the so-called "multi-messenger" approach …

Estimating Subsurface Anisotropy: Combining Waveform Tomography And Simulated Annealing, Michael Victor Afanasiev

Electronic Thesis and Dissertation Repository

Crosshole seismic tomography has been used by Vale to provide geophysical images of mineralized massive sulphides in the Eastern Deeps deposit at Voisey's Bay. High resolution seismic images are presented by applying acoustic waveform tomography to these data. In waveform tomography, an initial model is required which predicts the first arrival traveltimes to within a half-cycle of the lowest frequency in the data. Because seismic velocity anisotropy can be significant, the initial model must quantify the anisotropy, as well as the velocity, in order to meet the half-cycle criterion.

In our case study, difficulties were encountered in generating an accurate …

Azimuthal Seismic First-Arrival Tomography As A Proxy For Hydraulically Conductive Subsurface Fracture Networks, Matthew Brooks Edmunds

Masters Theses

The Oak Ridge Field Research Center (ORFRC) was established by the Environmental Sciences Division (ESD) at the Oak Ridge National Laboratory (ORNL) in Oak Ridge, TN, in order to study the various biogeochemical processes involved in the remediation as well as natural attenuation of a large contaminant plume that is extant in the vicinity of the ORIFRC. A part of this work has been to characterize the movement of this groundwater/contaminant plume with the use of azimuthal seismic first-arrival tomography (ASFT).

Within the general area of the ORIFRC, a 0-2 m layer of generally isotropic anthropogenic fill and unconsolidated soil …

Characterization Of Englacial Voids Using Radar Velocity Anisotropy, Joshua D. Nichols

Boise State University Theses and Dissertations

Glacial hydrology plays an important role in the motion and melt of glaciers. The transport of water through glacial ice is still poorly understood. Previous studies show that much of the water is stored and routed through planar voids within the glacier. From borehole observations and previous radar surveys, the voids appear to have a preferential orientation. Transverse waves, including radar waves, and shear seismic waves, travel at different velocities when polarized at different orientations relative to aligned inclusions. I conducted two georadar surveys on Bench glacier, in the Chugach Mountains, AK. Bench glacier has been the field site of …

Development Of Metal-Based Luminescent Probes For Applications In Biomolecular Structure And Dynamics, Ayesha Sharmin

Graduate Student Theses, Dissertations, & Professional Papers

New transition-metal complexes containing luminescent properties have been designed and synthesized for application as structural probes for biomolecules. Potential DNA intercalators, 2- amino-anthracene substituted triosmium clusters, were synthesized by the reactions of 2-aminoanthracene with [Os3(CO)10(CH3CN)2]. The products [Os3(CO)10(μ-η2-(N-C(1))-NH2C14H8)(μ- H)], [Os3(CO)10(μ-η2-(N-C(3))-NHC14H9)(μ-H)], [Os3(CO)9(μ-η2-(N-C(3))-NHC14H8)(μ-H)2] and [Os3(CO)9(μ3-η2-(N-C(3))-NHC10H9)(μ-H)] obtained from this reaction have been structurally characterized by spectroscopic, photophysical and electrochemical techniques. Solid state structures are also reported for the complexes [Os3(CO)10(μ-η2-(N-C(3))-NHC14H9)(μ-H)] and [Os3(CO)9(μ-η2-(N-C(3))-NHC14H8)(μ-H)2]. To investigate bio-macromolecular dynamics on the sub-microsecond-to-microsecond timescale, a series of ruthenium based mono-nuclear metalligand charge-transfer complexes (MLCs) of formula [XRu(CO)(L–L)(L′)2][PF6] (X = H, TFA, Cl; L–L = 2,2′-bipyridyl, 1,10-phenanthroline, 5-amino-1,10-phenanthroline …