# Physics Commons™

## All Articles in Physics

27,846 full-text articles. Page 2 of 717.

2018 Washington University in St. Louis

#### Lattice Scales From Gradient Flow And Chiral Analysis On The Milc Collaboration's Hisq Ensembles, Nathan Joseph Brown

##### Arts & Sciences Electronic Theses and Dissertations

The interactions of quarks and gluons form most of the visible matter around us. Yet, extracting precise predictions from the field theory describing them, Quantum Chromodynamics (QCD), is notoriously difficult. By simulating the QCD interaction on a Euclidean space time lattice, the field theory can be regularized non-perturbatively and familiar statistical techniques from classical statistical mechanics can be applied. Then, by systematically improving each component of the process, high precision results can be obtained. Some of the possible components to be improved include the discretization of the continuum action, the determination of the lattice scale(s), the generation of gauge ...

Quantum Fields In Extreme Backgrounds, 2018 Washington University in St. Louis

#### Quantum Fields In Extreme Backgrounds, Leandro Medina De Oliveira

##### Arts & Sciences Electronic Theses and Dissertations

Quantum field theories behave in interesting and nontrivial ways in the presence of intense electric and/or magnetic fields. Describing such behavior correctly, particularly at finite (nonzero) temperature and density, is of importance for particle physics, nuclear physics, astrophysics, condensed matter physics, and cosmology. Incorporating these conditions as external parameters also provides useful probes into the nonperturbative structure of gauge theories.

In this work, formalism for describing matter in a variety of extreme conditions is developed and implemented. We develop several expansions of one-loop finite temperature effects for spinor particles in the presence of magnetic fields, including the effects of ...

2018 Washington University in St. Louis

#### Deuterium Mas Nmr Studies Of Mg-Ti Deuteride Formed During High Pressure Ball Milling, Samuel Emery

##### Arts & Sciences Electronic Theses and Dissertations

Magnesium hydride has long been considered a candidate onboard hydrogen storage material for hydrogen fuel cell powered vehicles due to its low cost, abundance (of magnesium metal), and high hydrogen content (7.6 wt%). However, its use has been limited by the poor kinetics and thermodynamics of the reversible hydriding/dehydriding reaction. Improvements to hydrogen uptake and release have been previously demonstrated when Mg is alloyed with Sc. The resulting MgSc-hydride adopts a cubic, fluorite crystal structure (as opposed to the rutile, tetragonal structure for bulk MgH2) that exhibits a significantly lower activation energy for thermally driven hydrogen motion. However ...

Endorectal Digital Prostate Tomosynthesis, 2018 Louisiana State University and Agricultural and Mechanical College

#### Endorectal Digital Prostate Tomosynthesis, Joseph Robert Steiner

##### LSU Doctoral Dissertations

Several areas of prostate cancer (PCa) management, such as imaging permanent brachytherapy implants or small, aggressive lesions, benefit from high image resolution. Current PCa imaging methods can have inadequate resolution for imaging these areas. Endorectal digital prostate tomosynthesis (endoDPT), an imaging method that combines an external x-ray source and an endorectal x-ray sensor, can produce three-dimensional images of the prostate region that have high image resolution compared to typical methods. This high resolution may improve PCa management and increase positive outcomes in affected men.

This dissertation presents the initial development of endoDPT, including system design, image quality assessment, and examples ...

Chiral Topological Insulator Of Magnons, 2018 University of Nebraska - Lincoln

#### Chiral Topological Insulator Of Magnons, Bo Li, Alexey Kovalev

##### Faculty Publications, Department of Physics and Astronomy

We propose a magnon realization of 3D topological insulator in the AIII (chiral symmetry) topological class. The topological magnon gap opens due to the presence of Dzyaloshinskii-Moriya interactions. The existence of the topological invariant is established by calculating the bulk winding number of the system. Within our model, the surface magnon Dirac cone is protected by the sublattice chiral symmetry. By analyzing the magnon surface modes, we confirm that the backscattering is prohibited. By weakly breaking the chiral symmetry, we observe the magnon Hall response on the surface due to opening of the gap. Finally, we show that by changing ...

Phonon Dynamics Of Alkali Metals In The Hcp Lattice Structure, 2018 Utah State University

#### Phonon Dynamics Of Alkali Metals In The Hcp Lattice Structure, Jake Christensen

##### Physics Capstone Project

An Embedded-Atom-Method model that is successful at describing the vibrational properties of alkali metals in the BCC crystal structure is applied to the HCP structure. Phonon dispersion curves, density of states, and Debye temperatures are calculalated for Li, Na, K, Rb, and Cs. Comparison of BCC, FCC and HCP Debye temperatures show that BCC is the preferred structure at higher temperatures, which agrees with experiment.

Opportunities In Physics Education: Low-Cost Position Tracking For Use In Kinematics Labs, 2018 Portland State University

#### Opportunities In Physics Education: Low-Cost Position Tracking For Use In Kinematics Labs, Paul R. Destefano, Cora Siebert, Roberto Perez-Franco, Thomas Allen, Gabriel Mukobi, Ralf Widenhorn

##### Student Research Symposium

Traditional introductory physics kinematics laboratories utilized a few different instruments for locating objects in motion, all of which have shortcomings. Some provide only timing data, which heavily restricts trajectories and data collection. Some instruments provide more measurements but restrict object shapes, orientations, and textures. Still others require extensive pre-processing. None of these traditional instruments provide two- or three-dimensional position data. New, low-cost, local positioning technology, based on radio frequency wireless communications, is available that enables novel redesigns of physics laboratories. This technology provides two- and three-dimensional position measurements, continuously, at data rates of 10 Hz or faster, from any object ...

Diagnostic Platform For Current Health Status Monitoring, 2018 Portland State University

#### Diagnostic Platform For Current Health Status Monitoring, Albert S. Benight, Megan M. Koslen, Matthew W. Eskew

##### Student Research Symposium

Our approach is based on physical measurements of blood plasma and exploits the plethora of information contained in the human plasma proteome, as a reporter of human health status. The assay involves collection and analysis ofthermograms of plasma from human blood measured by differential scanning calorimetry (DSC).

Plasma thermograms arise from the temperature-induced denaturation profile of proteins within blood plasma measured by DSC. This insightful measurement thereby provides a snapshot of the current state of the human plasma proteome which directly informs on overall systemic health. Such measurements have been shown to be highly accurate and sensitive indicators of health ...

Increased A20-E3 Ubiquitin Ligase Interactions In Bid-Deficient Glia Attenuate Tlr3- And Tlr4-Induced Inflammation., 2018 Royal College of Surgeons in Ireland

#### Increased A20-E3 Ubiquitin Ligase Interactions In Bid-Deficient Glia Attenuate Tlr3- And Tlr4-Induced Inflammation., Sinéad Kinsella, Michael Fichtner, Orla Watters, Hans-Georg Konig, Jochen Hm Prehn

##### Physiology and Medical Physics Articles

Background: Chronic pro-inflammatory signaling propagates damage to neural tissue and affects the rate of disease progression. Increased activation of Toll-like receptors (TLRs), master regulators of the innate immune response, is implicated in the etiology of several neuropathologies including amyotrophic lateral sclerosis, Alzheimer’s disease, and Parkinson’s disease. Previously, we identified that the Bcl-2 family protein BH3-interacting domain death agonist (Bid) potentiates the TLR4-NF-κB pro-inflammatory response in glia, and specifically characterized an interaction between Bid and TNF receptor associated factor 6 (TRAF6) in microglia in response to TLR4 activation.

Methods: We assessed the activation of mitogen-activated protein kinase (MAPK) and ...

2018 George Fox University

#### Weatherall's "Void: The Strange Physics Of Nothing" (Book Review), Gary R. Averill

##### The Christian Librarian

No abstract provided.

2018 Utah State University

#### Investigating The Climatology Of Mesospheric And Thermospheric Gravity Waves At High Northern Latitudes, Michael Negale

##### All Graduate Theses and Dissertations

An important property of the Earth's atmosphere is its ability to support wave motions, and indeed, waves exist throughout the Earth's atmosphere at all times and all locations. What is the importance of these waves? Imagine standing on the beach as water waves come crashing into you. In this case, the waves transport energy and momentum to you, knocking you off balance. Similarly, waves in the atmosphere crash, known as breaking, but what do they crash into? They crash into the atmosphere knocking the atmosphere off balance in terms of the winds and temperatures. Although the Earth's ...

2018 Iowa State University

#### Phase Field Study Of Surface-Induced Melting And Solidification From A Nanovoid: Effect Of Dimensionless Width Of Void Surface And Void Size, Anup Basak, Valery I. Levitas

##### Physics and Astronomy Publications

The size effect and the effects of a finite-width surface on barrierless transformations between the solid (S), surface melt (SM), and melt (M) from a spherical nanovoid are studied using a phase field approach. Melting (SM → M and S → M) from the nanovoid occurs at temperatures which are significantly greater than the solid-melt equilibrium temperature θe but well below the critical temperature for solid instability. The relationships between the SM and M temperatures and the ratio of the void surface width and width of the solid-melt interface, Δ⎯⎯⎯, are found for the nanovoids of different sizes. Below a critical ratio ...

2018 Utah State University

#### Sodium Lidar For Mesopause Temperature And Wind Studies, Xiaoqi Xi

##### Physics Capstone Project

In 1990 Dr. Chiao-Yao She developed a narrowband Na Temperature lidar in Colorado State University (CSU), it immediately became an important instrument to measure the temperature in mesopause region (80-105 km in altitude): the atmospheric layer between mesosphere and thermosphere [Krueger et al., 2015]. Led by Dr. Tao Yuan, this system was relocated to Utah State University (USU) in summer 2010 and has been continuing its exploration of upper atmosphere. This report will give a brief introduction to the theory and application of Sodium Lidar.

Characterization Of Programmable Arduino Sensors, 2018 Utah State University

#### Characterization Of Programmable Arduino Sensors, Brett Mortenson

##### Physics Capstone Project

Arduinos are increasing in usage and prevalence due to the ease in which they can be programmed. External sensors attached to the Arduinos are being used for various measurements, and many of them give raw data output such as voltage spikes or decibel readings. These readings were characterized so that one can interpret the readings relatively easily, and understand more completely, the environment which the sensors are in. The sensors utilized are as follows: photoresistor, vibrational, sound, temperature, pressure, and humidity.

Atmospheric Gravity Wave Events Over Antarctica, 2018 Utah State University

#### Atmospheric Gravity Wave Events Over Antarctica, America Wrobel

##### Physics Capstone Project

This study used infrared (IR) image data obtained from McMurdo Station, Antarctica to investigate the properties of atmospheric gravity waves as they propagate into the upper mesosphere over Antarctica. The data were obtained as part of the international Antarctic Gravity Wave Instrument Network (ANGWIN). ANGWIN utilizes image data from several sites around Antarctica to investigate continent-wide propagation. This paper covers a study that reduced and analyzed two years of data from one particular site: McMurdo Station. An all-sky IR camera placed at McMurdo Station, Antarctica (77°83’ S, 166°61’ E) took one picture every ten seconds for the months ...

Mesoscale Computational Studies Of Thin-Film Bijels, 2018 University of Arkansas, Fayetteville

#### Mesoscale Computational Studies Of Thin-Film Bijels, Joseph M. Carmack

##### Theses and Dissertations

Bijels are a relatively new class of soft materials that have many potential applications in the technology areas of energy, medicine, and environmental sustainability. They are formed by the arrest of binary liquid spinodal decomposition by a dispersion of solid colloidal nanoparticles. This dissertation presents an in-depth simulation study of Bijels constrained to thin-film geometries and in the presence of electric fields. We validate the computational model by comparing simulation results with previous computational modeling and experimental research. In the absence of suspended particles, we demonstrate that the model accurately captures the rich kinetics associated with diffusion-based surface-directed spinodal decomposition ...

2018 University of Arkansas, Fayetteville

#### Near Bandgap Two-Photon Excited Luminescence Of Inas Quantum Dots, Xian Hu

##### Theses and Dissertations

Semiconductor quantum dots (QDs) confine carriers in three dimensions, resulting in atomic-like energy levels as well as size-dependent electrical and optical properties. Self-assembled III-V QD is one of the most studied semiconductor QDs thanks to their well-established fabrication techniques and versatile optical properties. This dissertation presents the photoluminescence (PL) study of the InAs/GaAs QDs with both above bandgap continuous-wave excitation (one-photon excitation) and below-bandgap pulse excitation (two-photon excitation). Samples of ensemble QDs, single QD (SQD), and QDs in a micro-cavity, all grown by molecular beam epitaxy, are used in this study. Morphology of these samples was examined using atomic ...

Diffraction Of Laguerre Gaussian Vortex Beams, 2018 University of Arkansas, Fayetteville

#### Diffraction Of Laguerre Gaussian Vortex Beams, Anindya Ambuj

##### Theses and Dissertations

The natural phenomenon of waves bending around obstacles is diffraction. Spatial characteristics of the diffraction pattern depends on the incident wave field, the shape, and size of the aperture. The diffraction of a plane wave of light by a slit and a circular aperture produce the sinc-squared and the Airy intensity patterns, respectively. On the contrary, the diffraction of Laguerre-Gauss vortex (LGV) beams by simple apertures such as a slit, circular apertures, and polygons show many unexpected features.

LGV beams have $\rho^{\ell}e^{i\ell\phi}$ transverse spatial dependence, where $\rho$ is the distance from the beam axis, \$\phi ...

Enhancing High-Order Harmonic Generation By Sculpting Waveforms With Chirp, 2018 University of Nebraska - Lincoln

#### Enhancing High-Order Harmonic Generation By Sculpting Waveforms With Chirp, Dian Peng, M. V. Frolov, Liang-Wen Pi, Anthony F. Starace

##### Anthony F. Starace Publications

We present a theoretical analysis showing how chirp can be used to sculpt two-color driving laser field waveforms in order to enhance high-order harmonic generation (HHG) and/or extend HHG cutoff energies. Specifically, we consider driving laser field waveforms composed of two ultrashort pulses having different carrier frequencies in each of which a linear chirp is introduced. Two pairs of carrier frequencies of the component pulses are considered: (ω, 2ω) and (ω, 3ω). Our results show how changing the signs of the chirps in each of the two component pulses leads to drastic changes in the HHG spectra. Our theoretical ...

2018 College of William and Mary