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Embedded-Atom-Method Modeling Of Alkali-Metal/Transition-Metal Interfaces, Jake D. Christensen 2020 Utah State University 81818app手机版下载

Embedded-Atom-Method Modeling Of Alkali-Metal/Transition-Metal Interfaces, Jake D. Christensen

All Graduate Theses and Dissertations

Understanding the thermal properties of materials is essential to using those materials for technological advancement which can benefit civilization. For example, it has been proposed that essential components of tokamaks, devices which perform fusion, be made out of tungsten with a thin layer of lithium on the surface. To that end, this thesis seeks to calculate the thermal properties of a layer of alkali atoms, like lithium and sodium, on tungsten and molybdenum substrates. We use an Embedded Atom Method (EAM) model to perform our calculations. This type of model has been widely used to describe the interaction between atoms ...


The Development And Use Of A Secondary Electron Yield Database For Spacecraft Charge Modeling, Phillip Lundgreen 2020 Utah State University

The Development And Use Of A Secondary Electron Yield Database For Spacecraft Charge Modeling, Phillip Lundgreen

All Graduate Theses and Dissertations

Charge modeling of electron-solid interactions requires a detailed and accurate compilation of experimental data on which to base its physics and against which to test its predictions. Historically researchers used methods involving individual research or information taken from existing, vague, databases that were often found wanting. To streamline the charge modeling process, a collection of data has been assembled and categorized based upon surface morphology and contamination from various published sources and existing databases. The quality and quantity of the compilation vary widely with very little information offered with regards to surface conditions of various materials (contamination, morphology, etc. ...). Included ...


Finite-Strain Scale-Free Phase-Field Approach To Multivariant Martensitic Phase Transformations With Stress-Dependent Effective Thresholds, Hamed Babaei, Valery I. Levitas 2020 Iowa State University

Finite-Strain Scale-Free Phase-Field Approach To Multivariant Martensitic Phase Transformations With Stress-Dependent Effective Thresholds, Hamed Babaei, Valery I. Levitas

Aerospace Engineering Publications

81818app手机版下载A scale-free phase-field model for martensitic phase transformations (PTs) at finite strains is developed as an essential generalization of small-strain models in Levitas et al. (2004) and Idesman et al. (2005). The theory includes finite elastic and transformational strains and rotations as well as anisotropic and different elastic properties of phases. The gradient energy term is excluded, and the model is applicable for any scale greater than 100 nm. The model tracks finite-width interfaces between austenite and the mixture of martensitic variants only; volume fractions of martensitic variants are the internal variables rather than order parameters. The concept of the ...


Issues And Proposed Solutions To Team Based Assessment In University Physics Labs, Manqoba Q. Hlatshwayo 2020 Western Michigan University

Issues And Proposed Solutions To Team Based Assessment In University Physics Labs, Manqoba Q. Hlatshwayo

STEM Instructional Graduate Teaching Assistant Posters

Many education experts considers peer-to-peer education as the most effective way for students to learn (Peersdom, 2014). Western Michigan University (WMU) physics laboratories embraces this philosophy and has designed the assessment to be based on the team report. The assumption is that every team member contributed (not necessarily equally) to the work submitted by the team hence every team member should receive the same grade. This is a ubiquitous assessment philosophy in education, and some forms of additional individual assessment in team projects are strongly discouraged (David Boud et al, 1999).

81818app手机版下载There is no doubt on the effectiveness of peer-to-peer ...


Improving Lab Experience For Students In Phys2080, Khushi Bhatt 2020 Western Michigan University

Improving Lab Experience For Students In Phys2080, Khushi Bhatt

STEM Instructional Graduate Teaching Assistant Posters

81818app手机版下载University Physics II (PHYS 2080) deals with providing hands-on experience with the experiments of electricity and magnetism. It aids students to develop computational thinking in physics through analysis of experimental and theoretical data using python programming language.

81818app手机版下载In Fall-2019, I taught the newly designed PHYS2080 class for the first time as per the requirements. During Spring-2020, I implemented some subtle changes using the skills that I gained through various teaching training. These changes are described in Methodology section. Data clearly shows improvement that was observed without lowering the expectations or changing the curriculum of the class.


Substitutional And Interstitial Doping In Laco5 System For The Development Of Hard Magnetic Properties: A First Principles Study, Huseyin Ucar, Renu Choudhary, Durga Paudyal 2020 California State Polytechnic University - Pomona

Substitutional And Interstitial Doping In Laco5 System For The Development Of Hard Magnetic Properties: A First Principles Study, Huseyin Ucar, Renu Choudhary, Durga Paudyal

Ames Laboratory Accepted Manuscripts

We investigate here the changes in the electronic structure at the transition metal sites of the RE-TM5 structure (RE = Rare Earth, TM = Transition Metal) while doping the interstitial sites with nitrogen. LaCo5 compound is taken as the baseline compound owing to its critically needed intrinsic magnetic properties such as magneto-crystalline anisotropy energy (MAE) of ≈5 meV/fu [1] due to the contributions from the cobalt network. In addition, because of the lack of 4f electrons in lanthanum, complications originating from the treatment of the 4f localized electrons are absent in this compound; making it an ideal reference material to all ...


Optical Study Of Pks B1322-110, The Intra-Hour Variable Radio Source, Juan P. Madrid, Artem V. Tuntsov, Mischa Schirmer, Mark A. Walker, Carlos J. Donzelli, Keith W. Bannister, Hayley E. Bignall, Jamie Stevens, Cormac Reynolds, Simon Johnston 2020 The University of Texas Rio Grande Valley 81818app手机版下载

Optical Study Of Pks B1322-110, The Intra-Hour Variable Radio Source, Juan P. Madrid, Artem V. Tuntsov, Mischa Schirmer, Mark A. Walker, Carlos J. Donzelli, Keith W. Bannister, Hayley E. Bignall, Jamie Stevens, Cormac Reynolds, Simon Johnston

Physics and Astronomy Faculty Publications and Presentations

81818app手机版下载Observations with the Australia Telescope Compact Array revealed intra-hour variations in the radio source PKS B1322-110 (Bignall et al. 2019). As part of an optical follow-up, we obtained Gemini Hα and Hα continuum (HαC) images of the PKS B1322-110 field. A robust 19 σ detection of PKS B1322- 110 in the Hα−HαC image prompted us to obtain the first optical spectrum of PKS B1322-110. With the Gemini spectrum we determine that PKS B1322-110 is a flat-spectrum radio quasar at a redshift of z = 3.007 ± 0.002. The apparent flux detected in the Hα filter is likely to originate ...


Spectral Properties Of Quaternionic Unit Gain Cycles, Nolan J. Coble 2020 State University of New York College at Brockport 81818app手机版下载

Spectral Properties Of Quaternionic Unit Gain Cycles, Nolan J. Coble

Senior Honors Theses

The quaternions are a non-commutative division ring that extends the complex numbers. A gain graph is a simple graph together with a gain function that assigns a value from an arbitrary group to each edge of the graph. We can define certain concepts on these graphs such as adjacency and Laplacian matrices, gains of paths, and more. If we restrict ourselves to the unit norm quaternions, we can define quaternionic unit gain graphs, or U(H)-gain graphs, as gain graphs where the domain of the gain function is the unit quaternions. Traditional methods from spectral graph theory are not ...


High Layer Uniformity Of 2-D Materials Surprisingly From Broad Features In Surface Electron Diffraction, Shen Chen, Michael Horn von Hoegen, Patricia A. Thiel, Adam Kaminski, Benjamin Schrunk, Thanassis Speliotis, Edward Henry Conrad, Michael C. Tringides 2020 Iowa State University and Ames Laboratory

High Layer Uniformity Of 2-D Materials Surprisingly From Broad Features In Surface Electron Diffraction, Shen Chen, Michael Horn Von Hoegen, Patricia A. Thiel, Adam Kaminski, Benjamin Schrunk, Thanassis Speliotis, Edward Henry Conrad, Michael C. Tringides

Chemistry Publications

81818app手机版下载Paradoxically a very broad diffraction background, named the Bell-Shaped-Component (BSC), has been established as a feature of graphene growth. Although the BSC has been present in the earlier literature it has been ignored. Recent diffraction studies as a function of electron energy have shown that the BSC is not related to scattering interference. The BSC is a very strong effect, but its origin is still unclear. Here, additional experiments are carried out as a function of temperature while monitoring changes in the intensity of different spots over the range that single-layer-graphene (SLG) grows. Quantitative fitting of the profiles shows that ...


Precision Measurement Of The Beam-Normal Single-Spin Asymmetry In Forward-Angle Elastic Electron-Proton Scattering, Qweak Collaboration, David Armstrong, Wouter Deconinck, K. Bartlett, J. C. Cornejo, R. D. Carlini, James F. Dowd, J. M. Finn, Valerie M. Gray, K. Grimm, J. R. Hoskins, J. P. Leckey, Jeong Han Lee, Joshua A. Magee, Victoria F. Owen 2020 William & Mary

Precision Measurement Of The Beam-Normal Single-Spin Asymmetry In Forward-Angle Elastic Electron-Proton Scattering, Qweak Collaboration, David Armstrong, Wouter Deconinck, K. Bartlett, J. C. Cornejo, R. D. Carlini, James F. Dowd, J. M. Finn, Valerie M. Gray, K. Grimm, J. R. Hoskins, J. P. Leckey, Jeong Han Lee, Joshua A. Magee, Victoria F. Owen

Arts & Sciences Articles

81818app手机版下载A beam-normal single-spin asymmetry generated in the scattering of transversely polarized electrons from unpolarized nucleons is an observable related to the imaginary part of the two-photon exchange process. We report a 2% precision measurement of the beam-normal single-spin asymmetry in elastic electron-proton scattering with a mean scattering angle of theta_lab = 7.9 degrees and a mean energy of 1.149 GeV. The asymmetry result is B_n = -5.194 +- 0.067 (stat) +- 0.082 (syst) ppm. This is the most precise measurement of this quantity available to date and therefore provides a stringent test of two-photon exchange models at far-forward scattering ...


Particle Dynamics In Anti-De Sitter Space By Eih Method, Jiusi Lei 2020 The Graduate Center, City University of New York

Particle Dynamics In Anti-De Sitter Space By Eih Method, Jiusi Lei

Dissertations, Theses, and Capstone Projects

Following the work of Einstein, Infeld and Hoffmann, we show that particle dynamics in Anti-de Sitter spacetime can be built up by regarding singularities in spacetime manifold as the source of particles.

81818app手机版下载Since gauge fields play a foundational role in the action, the singularities are chosen to be point-like instantons. Their winding number, defined by an integration on the spheres surrounding those singularities, will turn out to be related to their masses. And their action, derived from the Chern-Simons forms, will be a co-adjoint orbit action, with group element g ∈ SO(4, 2) describing the collective coordinates of the particle ...


Wave Propagation In Random And Topological Media, Yuhao Kang 2020 The Graduate Center, City University of New York

Wave Propagation In Random And Topological Media, Yuhao Kang

Dissertations, Theses, and Capstone Projects

This thesis discusses wave propagation in two kinds of systems, random media and topological insulators. In a disordered system, the wave is randomized by multiple scattering. The scattering matrix and associated delay times are powerful tools with which to describe wave transport. We discuss the relation among the Wigner time, the transmission time, and energy density in a lossless or lossy system. We propose the zeros of the transmission matrix and show how to manipulate the zero-transmission mode in a nonunitary system. In a photonic topological insulator, we realize an edge mode and discuss its robustness in the face of ...


An Accurate Solution Of The Self-Similar Orbit-Averaged Fokker-Planck Equation For Core-Collapsing Isotropic Globular Clusters: Properties And Application, Yuta Ito 2020 The Graduate Center, City University of New York

An Accurate Solution Of The Self-Similar Orbit-Averaged Fokker-Planck Equation For Core-Collapsing Isotropic Globular Clusters: Properties And Application, Yuta Ito

Dissertations, Theses, and Capstone Projects

Hundreds of dense star clusters exist in almost all galaxies. Each cluster is composed of approximately ten thousand through ten million stars. The stars orbit in the clusters due to the clusters' self-gravity. Standard stellar dynamics expects that the clusters behave like collisionless self-gravitating systems on short time scales (~ million years) and the stars travel in smooth continuous orbits. Such clusters temporally settle to dynamically stable states or quasi-stationary states (QSS). Two fundamental QSS models are the isothermal- and polytropic- spheres since they have similar structures to the actual core (central part) and halo (outskirt) of the clusters. The two ...


Electromagnetic Reciprocity In The Presence Of Topological Insulators, Huai-Yi Xie, P. T. Leung 2020 Institute of Nuclear Energy Research

Electromagnetic Reciprocity In The Presence Of Topological Insulators, Huai-Yi Xie, P. T. Leung

Physics Faculty Publications and Presentations

Electromagnetic reciprocity is studied in the presence of topological insulators (TI) with application of axion electrodynamics for harmonic electromagnetic fields. The corresponding generalized Lorentz and Feld-Tai type lemmas are derived in terms of the axion coupling parameter, and their correlation to the conditional symmetry in source-observer coordinates for the various Green dyadics is established subjected to different types of boundary conditions. Possible application of the results to the probing of the topological magneto-electric effects from TI is discussed.


Variability Of Active Galactic Nuclei From Differential Photometry, Nicholas Steven Yee 2020 California Polytechnic State University, San Luis Obispo

Variability Of Active Galactic Nuclei From Differential Photometry, Nicholas Steven Yee

Physics

The Seoul AGN Monitoring Project, or SAMP for short, is an international project (PI Jonghak Woo from Korea) with the goal of measuring the masses of black holes residing in the center of massive active galactic nuclei (AGNs). AGNs are some of the brightest objects in the universe. Their light is attributed to the accretion of material onto the black hole. However, these objects are too distant to spatially resolve the gravitational sphere of influence of the black hole directly. Instead, we use a technique called reverberation mapping which observes the variability of the AGN power-law continuum emission and the ...


New Techniques For Holography From Supergravity, Oscar Varela 2020 Utah State University 81818app手机版下载

New Techniques For Holography From Supergravity, Oscar Varela

Funded Research Records

81818app手机版下载No abstract provided.


Yield-Stress Fluids In Confined Geometries, Thalia Magyar 2020 The University of Western Ontario

Yield-Stress Fluids In Confined Geometries, Thalia Magyar

Electronic Thesis and Dissertation Repository

A yield-stress fluid is a material that has properties of both solids and conventional liquids that only begins to flow when subject to a finite stress. The behaviour of yield-stress fluids is interesting and important in many applications. It is expected that the rheological properties of a yield-stress fluid will change when confined to a region with a length scale comparable to the characteristic scale of its microstructure. The particle size and polydispersity of two yield-stress fluids, Carbopol and poly(N-isopropylacrylamide), were determined using dynamic light scattering. A rheological characterization was performed on these two yield-stress fluids. Flow of ...


Understanding The Magnetic Properties Of Ii-Vi Semiconductor Nanocrystals, Alex Khammang 2020 University of Maine

Understanding The Magnetic Properties Of Ii-Vi Semiconductor Nanocrystals, Alex Khammang

Electronic Theses and Dissertations

81818app手机版下载Semiconductor nanocrystals (NC) are well known for their unique size tunable optical properties making them suitable candidates for devices such as light emitting diodes (LEDs), solar cells, and cellular labels. II-VI semiconductors in the bulk form behave diamagnetically, but can inherit paramagnetic (PM) or ferromagnetic (FM) properties at the nanoscale. Reports suggest that the emergence of weak PM or FM behavior in undoped NCs are attributed to the increased surface to volume ratio compared for NCs. Traditionally, these NCs only obtain magnetic properties after doping with certain transition metals, such as Co, Mn, or Fe. Many mechanisms have been proposed ...


Elmer Fem-Dakota: A Unified Open-Source Computational Framework For Electromagnetics And Data Analytics, Anjali Sandip 2020 University of North Dakota

Elmer Fem-Dakota: A Unified Open-Source Computational Framework For Electromagnetics And Data Analytics, Anjali Sandip

Mechanical Engineering Faculty Publications

Open-source electromagnetic design software, Elmer FEM, was interfaced with data analytics toolkit, Dakota. Furthermore, the coupled software was validated against a benchmark test. The interface developed provides a unified open-source computational framework for electromagnetics and data analytics. Its key features include uncertainty quantification, surrogate modelling and parameter studies. This framework enables a richer understanding of model predictions to better design electric machines in a time sensitive manner.


H-Atom Ladder Operator Revisited, Carl W. David 2020 University of Connecticut

H-Atom Ladder Operator Revisited, Carl W. David

Chemistry Education Materials

81818app手机版下载An error laden note (Am. J. Phys., 34, 984,(1966)) concerning the ladder operator solution to the hydrogen atom electronic energy levels is corrected.