Other Physics Commons^™

Exclusive Neutral Pion Electroproduction Cross Section Measurements With A Neutral Particle Spectrometer, Mitchell R. Kerver

Physics Theses & Dissertations

Deep Virtual Compton Scattering (DVCS), the exclusive electron-proton scattering process ep →e′p′γ, provides access to generalized parton distributions (GPDs), which correlate informa tion about the longitudinal momentum and transverse spatial structure of quarks inside the nucleon. Experiment E12-13-010 in Hall C at Jefferson Lab was designed to take high-precision measure ments of the DVCS cross section over an extended kinematic range using the newly commis sioned Neutral Particle Spectrometer (NPS). The NPS features a high-resolution electromagnetic calorimeter and a streaming data acquisition system optimized for operation at high luminosities. This thesis presents the detector and analysis work carried out to …

Atmospheric Chemistry Experiment (Ace) Winds, Matthew Wyatt, Peter F. Bernath, Chris Boone, Léo Lavy, Ryan Johnson

Chemistry & Biochemistry Faculty Publications

The Atmospheric Chemistry Experiment Fourier Transform Spectrometer (ACE-FTS) uses limb geometry to measure transmittance spectra of Earth's atmosphere by solar occultation. Line-of-sight wind speeds can be derived via Doppler shifts of molecular lines in infrared spectra. The wind look direction angles relative to geodetic North are derived from geometry. We validate the new ACE version 5.3 (v.5.3) line-of-sight winds with MIGHTI and meteor radar vector wind observations and find a ±15 m/s sunrise/sunset shift above 80 km. We also compare line-of-sight winds from ACE-FTS v.5.2 and v.5.3 with vector winds from the MERRA-2, HWM14, and WACCM-X models. A ±15 m/s …

Exploring Physics Teacher Identity: Pathways Toward Equitable Instruction Among Teachers, Clausell Mathis, Jomo Mutegi, Turhan Carroll, Maya Patel, Andrea Wooley

Teaching & Learning Faculty Publications

Physics teacher identity encompasses teachers' beliefs and views toward being a physics teacher. Physics teacher identity is influenced by teachers' perspectives on physics teaching and learning. Previous studies on teacher identity in general suggest that the construct is complex and malleable. Studies further suggest that it influences instructional methods, student engagement, and classroom environment. However, within physics education, there has yet to be an examination of how physics teacher identity influences "equitable" teaching approaches. This qualitative study sought to identify various dimensions of physics teacher identity and its implications for physics education research. We interviewed secondary and postsecondary physics teachers …

Accelerating The Efficiency Of Multiscale Hybridizable Discontinuos Galerkin Methods For Flows In Heterogeneous Media, Tony Charles Haines

Mathematics & Statistics Theses & Dissertations

A plethora of scientific and engineering problems encountered are multiscale in nature. This multiscale feature often influences simulation efforts wherever large disparities in spatial scales are experienced. Notable examples include composite materials, fluid flow through porous media and turbulent transport in high Reynolds number flow. Although there are promising results from the advancement of modern supercomputer, obtaining direct numerical solution of multiscale problems is very laborious. This difficulty stems from the tremendous amount of computer memory and CPU time required. Parallel computing may be one obvious choice in remedying this issue. However, the complexity and size of the discrete problem …

Snow Spheres And Ice Cubes: Solutions For Fermi Questions, February 2024, John Adam

Mathematics & Statistics Faculty Publications

No abstract provided.

Proof Of Principle For A Self-Governing Prediction And Forecasting Reward Algorithm, Jose Osvaldo Gonzalez-Hernandez, Jonathan Marino, Ted Rogers, Brandon Velasco

Physics Faculty Publications

We use Monte Carlo techniques to simulate an organized prediction competition between a group of scientific experts acting under the influence of a "self-governing" prediction reward algorithm. Our aim is to illustrate the advantages of a specific type of reward distribution rule that is designed to address some of the limitations of traditional forecast scoring rules. The primary extension of this algorithm as compared with standard forecast scoring is that it incorporates measures of both group consensus and question relevance directly into the reward distribution algorithm. Our model of the prediction competition includes parameters that control both the level of …

Cats, Dogs, And Roll Waves, John Adam

Mathematics & Statistics Faculty Publications

This article discusses the phenomenon of roll waves, which are shock-like patterns separated by smooth profiles that occur in flood waves. The author mentions that in a steady-state situation, the drag forces on the water in the channel are balanced by the down-slope gravitational force. The article also includes questions for readers to estimate the speed and length of the roll waves, as well as determine the stability of the flow. The author provides additional information about the Chezy formula, an empirical equation used in fluid mechanics to estimate the mean flow velocity of open channel flow.

Cats, Dogs, And Roll Waves: Solutions For Fermi Questions, April 2024, John Adam

Mathematics & Statistics Faculty Publications

On a hot afternoon in western North Carolina, the heavens opened and (to mix metaphors) it started raining “cats and dogs.” The rain was torrential, and soon a river of water was flowing downhill into the parking lot. In rivers and dam spillways, these are known as flood waves. The picture shows a particular type of flood waves known s roll waves—shock-like patterns separated by smooth profiles. In a steady-state situation, the drag forces on the water in the channel are balanced by the down-slope gravitational force. The dimensionless friction coefficient is C, the stream depth is h, v is …

Snow Spheres And Ice Cubes, John Adam

Mathematics & Statistics Faculty Publications

This article, titled "Snow spheres and ice cubes," discusses the melting of snowballs and ice cubes. It explains that in standard calculus textbooks, it is shown that a snowball melting at a rate proportional to its surface area will have its radius decrease at a constant rate, assuming it remains spherical as it melts. The article then poses several questions related to this concept, including the proportion of a smaller snow sphere that remains when half of a larger one has melted, the value of p for which the smaller sphere first melts, and the volume reduction factor for cubes …

Faster, Cheaper, And Better Cfd: A Case For Machine Learning To Augment Reynolds-Averaged Navier-Stokes, John Peter Romano Ii

Mechanical & Aerospace Engineering Theses & Dissertations

In recent years, the field of machine learning (ML) has made significant advances, particularly through applying deep learning (DL) algorithms and artificial intelligence (AI). The literature shows several ways that ML may enhance the power of computational fluid dynamics (CFD) to improve its solution accuracy, reduce the needed computational resources and reduce overall simulation cost. ML techniques have also expanded the understanding of underlying flow physics and improved data capture from experimental fluid dynamics.

This dissertation presents an in-depth literature review and discusses ways the field of fluid dynamics has leveraged ML modeling to date. The author selects and describes …

Not Your Typical Tower Of Sauron, John Adam

Mathematics & Statistics Faculty Publications

The picture is of the tapering Chester Shot Tower, located in Chester, England. It was built in 1799 for the manufacture of lead shot for use in the Napoleonic Wars. Molten lead was poured through a sieve at the top of the tower, with the tiny droplets forming perfect spheres during the fall; these were then cooled in a vat of water at the base. This process was less labor intensive than an earlier method using molds. It is the oldest of the three remaining shot towers in the UK.

Question 1: Using the parked van at the base, estimate …

Oscillating Icebergs, John Adam

Mathematics & Statistics Faculty Publications

No abstract provided.

"Density" Of Light And Pi, John Adam

Mathematics & Statistics Faculty Publications

Question 1: What is the linear “density” of the spectral range on the ceiling? The crown molding is common for an older (circa 1925) house.

Question 2: The glass shown is a standard 16-oz. water glass engraved with many digits of pi. (The dimensions appear somewhat distorted because of the camera angle chosen to enhance the contrast of the numerals against the dark background.)

More On The Demons Of Thermodynamics, Daniel P. Sheehan, Garret Moddel, James W. Lee

Chemistry & Biochemistry Faculty Publications

No abstract provided.

A Comparison Of Uniaxial Compressive Response And Inelastic Deformation Mechanisms In Freeze Cast Alumina-Epoxy Composites Without And With Rigid Confinement, Tareq Aljuhari

Mechanical & Aerospace Engineering Theses & Dissertations

Cellular ceramics have an array of improved mechanical properties that make them incredibly desired for different applications such as armor systems, aircraft structures, automobiles bumpers, and biomedical implants. It is also desirable that porous architecture could be shaped into bulk complicated shapes and easy to scale-up with low manufacturing cost. Despite several efficient techniques to fabricate cellular ceramics, some limitations are preventing us from meeting the high demand of the after mentioned applications. For that, freeze casting, also called ice-templating, is technique of solidifying an aqueous ceramic suspension under the effect of unidirectional temperature gradient. In this study, Ice-templated porous …

Lattice Optics Optimization For Recirculatory Energy Recovery Linacs With Multi-Objective Optimization, Isurumali Neththikumara, Todd Satogata, Alex Bogacz, Ryan Bodenstein, Arthur Vandenhoeke

College of Sciences Posters

Beamline optics design for recirculatory linear accelerators requires special attention to suppress beam instabilities arising due to collective effects. The impact of these collective effects becomes more pronounced with the addition of energy recovery (ER) capability. Jefferson Lab’s multi-pass, multi-GeV ER proposal for the CEBAF accelerator, ER@CEBAF, is a 10- pass ER demonstration with low beam current. Tighter control of the beam parameters at lower energies is necessary to avoid beam break-up (BBU) instabilities, even with a small beam current. Optics optimizations require balancing both beta excursions at high-energy passes and overfocusing at low-energy passes. Here, we discuss an optics …

Rock Paintings: Solutions For Fermi Questions, September 2022, John Adam

Mathematics & Statistics Faculty Publications

No abstract provided.

Question 1: Snow Volume; Question 2: Longbow Arrow Velocity, Larry Weinstein

Physics Faculty Publications

No abstract provided.

Solutions For Fermi Questions, January 2022: Question 1: Snow Volume; Question 2: Longbow Arrow Velocity, Larry Weinstein

Physics Faculty Publications

No abstract provided.

Question 1: Ketchup Packets; Question 2: Dog Hair, Larry Weinstein

Physics Faculty Publications

Question 2: Dog hair How much dog hair is shed (and subsequently vacuumed) in the U.S. each year? How many ketchup packets are used in America every year?.

Question 1: Dinosaur Killer Crater; Question 2: Graduation Speeches, Larry Weinstein

Physics Faculty Publications

The Fermi Questions: In 2003, the "Dinosaur Killer" asteroid crater was imaged for the first time (see National Geographic News, March 7, 2003). The crater is believed to be 100 km in radius and 1 km deep. What was the kinetic energy of the asteroid that made the crater? Express your answer in joules and in megatons (1 MT = 4 ·10 J).

Solutions For Fermi Questions, April 2022, Larry Weinstein

Physics Faculty Publications

[Introduction] Answer: When an asteroid hits the Earth, it transfers thermal and kinetic energy to the ground. The kinetic energy moves rock and makes a crater. We'll start by estimating the kinetic energy needed to make a crater.

Question 1: Space Telescope; Question 2: Jwst2, Larry Weinstein

Physics Faculty Publications

[Introduction] Space telescope

Question 1: If the James Webb Space Telescope could be turned to face Earth, how small an object could it resolve? How does that compare to the Hubble Space Telescope? ...

Question 2: How much heat from Earth is blocked by the Sun and Earth shade of the James Webb Space Telescope? ...

Question: While I was at a Norfolk Tides baseball game, a foul ball landed in the section above me and showered some of my friends with beer. What is the probability of a foul ball landing directly in a cup of beer during one …

Solutions For Fermi Questions, March 2022, Larry Weinstein

Physics Faculty Publications

Answers the questions:

Question 1: Ketchup packets

How many ketchup packets are used in America every year?

Question 2: Dog hair

How much dog hair is shed (and subsequently vacuumed) in the U.S. each year?

Solutions For Fermi Questions, May 2022, Larry Weinstein

Physics Faculty Publications

[Introduction] Question: If the James Webb Space Telescope could be turned to face the Earth, how small an object could it resolve? How does that compare to the Hubble Space Telescope?.

To answer this, we need to know the location of the JWST, its size, and the wavelengths it can image. (This is one of those Fermi questions where we're not really estimating, but we are calculating unusual order-of-magnitude answers.) The JWST is orbiting the Earth and Sun at the second Lagrange point, L2, which is located 1.5 × 10⁶ km beyond the Earth (so that the Sun, Earth and …

Work-In-Progress: Rapid Development Of Advanced Virtual Labs For In-Person And Online Education, Yiyang Li, Yuzhong Shen, Charles Sukenik, Brian Sanders, Pauline Delacruz, Justin Mason

Electrical & Computer Engineering Faculty Publications

During the closure of K-12 schools and universities thanks to the COVID-19 pandemic, many educators turned to web conferencing tools such as Zoom and WebEx to deliver online lectures. For courses with labs, some teachers provide recorded videos of real labs. Watching recorded lab videos is a passive experience, as the procedures and point of view are fixed, and students do not have any control of the lab and thus miss the opportunity to explore different options, including making mistakes that is important part of the learning process. One approach that holds great potential to enhance laboratory experience for online …

High-Order Positivity-Preserving L2-Stable Spectral Collocation Schemes For The 3-D Compressible Navier-Stokes Equations, Johnathon Keith Upperman

Mathematics & Statistics Theses & Dissertations

High-order entropy stable schemes are a popular method used in simulations with the compressible Euler and Navier-Stokes equations. The strength of these methods is that they formally satisfy a discrete entropy inequality which can be used to guarantee L₂ stability of the numerical solution. However, a fundamental assumption that is explicitly or implicitly used in all entropy stability proofs available in the literature for the compressible Euler and Navier-Stokes equations is that the thermodynamic variables (e.g., density and temperature) are strictly positive in the entire space{time domain considered. Without this assumption, any entropy stability proof for a numerical scheme …

Development And Applications Of Adjoint-Based Aerodynamic And Aeroacoustic Multidisciplinary Optimization For Rotorcraft, Ramiz Omur Icke

Mechanical & Aerospace Engineering Theses & Dissertations

Urban Air Mobility (UAM) is one of the most popular proposed solutions for alleviating traffic problems in populated areas. In this context, the proposed types of vehicles mainly consist of rotors and propellers powered by electric motors. However, those rotary-wing components can contribute excessively to noise generation. Therefore, a significant noise concern emerges due to urban air vehicles in or around residential areas. Reducing noise emitted by air vehicles is critically important to improve public acceptance of such vehicles for operations in densely populated areas.

Two main objectives of the present dissertation are: (1) to expand the multidisciplinary optimization to …

Fermi Questions, Question 1: Light Bulb Photons; Question 2: Light Bulbs, Larry Weinstein

Physics Faculty Publications

No abstract provided.

Solutions For Fermi Questions, March 2021, Larry Weinstein

Physics Faculty Publications

No abstract provided.