Physics Commons^™

Charge Transport And Electron Emission Of Disordered Materials: Extensions Of The Walden-Wintle Model For Charge Injection With Electron Beams, Jr Dennison, Alec Sim, Gregory Wilson, Jodie C. Gillespie

Presentations

No abstract provided.

Pre-Breakdown Arcing And Electrostatic Discharge In Dielectrics Under High Dc Electric Field Stress, Allen Andersen, Jr Dennison

Presentations

No abstract provided.

Small Satellite Space Environments Effects Test Facility, Jr Dennison, Justin Dekany, Kent Hartley, James S. Dyer, Robert H. Johnson

Presentations

No abstract provided.

One-Dimensional Weakly Nonlinear Model Equations For Rossby Waves, David Henry, Rossen Ivanov

Articles

In this study we explore several possibilities for modelling weakly nonlinear Rossby waves in fluid of constant depth, which propagate predominantly in one direction. The model equations obtained include the BBM equation, as well as the integrable KdV and Degasperis-Procesi equations.

Density Of State Models And Temperature Dependence Of Radiation Induced Conductivity, Jodie C. Gillespie, Jr Dennison, Alec Sim

Presentations

No abstract provided.

Defects Density Of States Model Of Cathodoluminescent Intensity And Spectra Of Disordered Sio2, Amberly Evans Jensen, Jr Dennison

Presentations

No abstract provided.

Electrostatic Discharge And Endurance Time Measurements Of Spacecraft Materials: A Defect-Driven Dynamic Model, Allen Andersen, Jr Dennison, Alec Sim, Charles Sim

Presentations

No abstract provided.

Synergistic Models Of Electron Emission And Transport Measurements Of Disordered Sio2, Jr Dennison, Justin Dekany, Jodie C. Gillespie, Phil Lundgreen, Allen Andersen, Amberly Evans, Greg Wilson, Alec Sim, Ryan Carl Hoffmann

Presentations

No abstract provided.

Variations In Cathodoluminescent Intensity Of Spacecraft Materials Exposed To Energetic Electron Bombardment, Justin Dekany, Justin Christensen, Jr Dennison, Amberly Evans, Greg Wilson, Todd Schneider, Charles W. Bowers, Robert H. Meloy

Presentations

No abstract provided.

Measurements Of Intrinsic Electron Emission Yields Of High Resistivity Ceramic Materials, Justin Dekany, Jr Dennison, Ryan Carl Hoffmann, Clint D. Thomson, Ender Savrun

Presentations

No abstract provided.

Magnetism Of Zn-Doped Sno2: Role Of Surfaces, Pushpa Raghani, Balaji Ramanujam

Physics Faculty Publications and Presentations

Surface effects on the magnetization of Zn-doped SnO₂ are investigated using first principles method. Magnetic behavior of Zn-doped bulk and highest and lowest energy surfaces—(001) and (110), respectively, are investigated in presence and absence of other intrinsic defects. The Zn-doped (110) and (001) surfaces of SnO₂ show appreciable increase in the magnetic moment (MM) compared to Zn-doped bulk SnO₂. Formation energies of Zn defects on both the surfaces are found to be lower than those in bulk SnO₂. Zn doping favors the formation of oxygen vacancies. The density of states analysis on the Zn-doped (110 ...

Dynamics Of And On Complex Networks, Arda Halu

Physics Dissertations

Complex networks are dynamic, evolving structures that can host a great number of dynamical processes. In this thesis, we address current challenges regarding the dynamics of and dynamical processes on complex networks. First, we study complex network dynamics from the standpoint of network growth. As a quantitative measure of the complexity and information content of networks generated by growing network models, we define and evaluate their entropy rate. We propose stochastic growth models inspired by the duplication-divergence mechanism to generate epistatic interaction networks and find that they exhibit the property of monochromaticity as a result of their dynamical evolution. Second ...

Electronic & Magnetic Properties Of Ba(Fe,Co)2as2 & Uru2si2, Travis J. Williams

Open Access Dissertations and Theses

This thesis details a collection of experiments performed on two condensed matter systems, Co-doped BaFe₂As₂ and URu₂Si₂. These two materials are related by their structural type (ThCr₂Si₂-type) serving as great examples of the diversity of material properties present in this family. They are also both superconducting materials and belong to the collection of strongly-correlated electron systems. The interest in studying the Ba(Fe,Co)₂As₂ group of materials is due to the high superconducting transition temperature in these (and related) materials, while the compound URu₂Si_{2 ...}

Phase Field Crystal Studies Of Strain-Mediated Effects In The Thermodynamics And Kinetics Of Interfaces, Jonathan F E Stolle

Open Access Dissertations and Theses

In this dissertation, the Phase Field Crystal (PFC) Method is used to study a number of problems in which interfaces and elastic effects play important roles in alloys. In particular, the three topics covered in this work are grain boundary thermodynamics in alloys, dislocation-mediated formation of clusters in binary and ternary alloys, and solutal effects in explosive crystallization. Physical phenomena associated with grain boundaries, such as Read-Shockley-like behaviour and Gibbs adsorp- tion theorem, were shown to be accurately captured in both PFC- and XPFC-type models. In fact, a connection between the solute segregation behaviour and physical properties of the system ...

Neutron Scattering Studies Of Magnetic Oxides Based On Triangular Motifs, Katharina Fritsch

Open Access Dissertations and Theses

The following dissertation presents neutron scattering studies on three specific magnetic insulating oxide materials whose lattice is based on triangular structural motifs. Each of the three materials studied, LuCoGaO₄, Co₃V₂O₈ and Tb₂Ti₂O₇, displays an interesting disordered ground state that is reached by different mechanisms: site disorder, geometric frustration, and quantum fluctuations induced by a transverse magnetic field. The main focus of this work is the characterization of the resulting magnetic ground states and magnetic excitations within these systems.

Chapters 3, 4 and 5 contain original work in the form ...

Development Of A Thgem Imaging Detector With Delay Line Readout, Andrei Hanu

Open Access Dissertations and Theses

Position sensitive detectors represent a class of particle detectors widely used in high-energy physics, astrophysics, biophysics and medicine for imaging the spatial distribution of various radioactive sources. In recent years, a new class of gas based detectors, so-called micropattern gas detectors (MPGDs), has emerged. While modern MPGDs rival solid state detectors in terms of spatial and temporal resolution, their cost of production is significantly lower. A Thick Gaseous Electron Multiplier (THGEM) imaging detector, with a two-dimensional delay line readout, has been constructed as a concept for a large area imaging detector with reasonable spatial resolution. The delay line based THGEM ...

Resonant Curved Piezoelectric Cantilever Fluid Diode Wings For Mass-Producible Flying Microrobots, Matthew D. Minnick

Open Access Dissertations and Theses

This work explores a new method of force generation for flying robots on the sub-cm wingspan scale: resonant curved piezoelectric cantilevers created using completely parallel MEMS fabrication. It theorizes that because a resonating curved beam has a different drag coefficient on the upstroke than the downstroke, it should act as a fluid diode: a partial one-way gate for fluids, and thereby generate an asymmetric force over a symmetric one-degree-of-freedom flapping cycle. It develops a simplified model for the large-amplitude resonant mode of thin circular arcs by analytically extending the resonant mode shape of straight cantilevers, shows that this shape is ...

Capture Of Magnetic Inelastic Dark Matter In The Sun, Matthew Mccreadie

Open Access Dissertations and Theses

We consider the phenomenology of the Magnetic Inelastic Dark Matter model, specifically its capture and subsequent annihilation in the Sun. By using the most recent data from the IceCube and Super- Kamiokande neutrino detection experiments, we are able to put limits on the dipole moment of this WIMP candidate for masses ranging from 100 GeV to 10 TeV with a mass-splitting ranging from 0 to 200 keV. Limits are placed on a 100 GeV WIMP with magnetic dipole interactions as low as 2.6 × 10^−6µN for an inelastic parameter of 100 keV

Valence Bond Calculations For Quantum Spin Chains: From Impurity Entanglement And Incommensurate Behaviour To Quantum Monte Carlo, Andreas Deschner

Open Access Dissertations and Theses

In this thesis I present three publications about the use of
valence bonds to gain information about quantum spin systems.
Valence bonds are an essential ingredient of low energy states present
in many compounds.

The first part of this thesis is dedicated to
two studies of the antiferromagnetic J₁-J₂ chain with
S=1/2. We show how automated variational calculations based on
valence bond states can be performed close to the Majumdar-Ghosh point
(MG-point). At this point, the groundstate is a product state of
dimers (valence bonds between nearest neighbours). In the dimerized
region surrounding the MG-point ...

Nuclear Proliferation And Testing: A Tale Of Two Treaties, Pierce S. Corden, David Hafemeister

Physics

Despite progress in reducing stockpiles after the end of the Cold War, the disturbing actions of some nations could spread nuclear weapon capabilities and enlarge existing arsenals.