Faster, Cheaper, And Better Cfd: A Case For Machine Learning To Augment Reynolds-Averaged Navier-Stokes, 2023 Old Dominion University
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 …
Superoscillations And Fock Spaces, 2023 Chapman University
Superoscillations And Fock Spaces, Daniel Alpay, Fabrizio Colombo, Kamal Diki, Irene Sabadini, Daniele C. Struppa
Mathematics, Physics, and Computer Science Faculty Articles and Research
In this paper we use techniques in Fock spaces theory and compute how the Segal-Bargmann transform acts on special wave functions obtained by multiplying superoscillating sequences with normalized Hermite functions. It turns out that these special wave functions can be constructed also by computing the approximating sequence of the normalized Hermite functions. First, we start by treating the case when a superoscillating sequence is multiplied by the Gaussian function. Then, we extend these calculations to the case of normalized Hermite functions leading to interesting relations with Weyl operators. In particular, we show that the Segal-Bargmann transform maps superoscillating sequences onto …
Trumpet Directivity From A Rotating Semicircular Array, 2023 Brigham Young University
Trumpet Directivity From A Rotating Semicircular Array, Samuel D. Bellows, Joseph E. Avila, Timothy W. Leishman
Directivity
The directivity function of a played musical instrument describes the angular dependence of its acoustic radiation and diffraction about the instrument, musician, and musician’s chair. Directivity influences sound in rehearsal, performance, and recording environments and signals in audio systems. Because high-resolution, spherically comprehensive measurements of played musical instruments have been unavailable in the past, the authors have undertaken research to produce and share such data for studies of musical instruments, simulations of acoustical environments, optimizations of microphone placements, and other applications. The authors acquired the data from repeated chromatic scales produced by a trumpet played at mezzo-forte in an anechoic …
Ferroelectric Hafnia Surface In Action, 2023 University of Nebraska-Lincoln
Ferroelectric Hafnia Surface In Action, Xia Hong
Nebraska Center for Materials and Nanoscience: Faculty Publications
Piezoresponse microscopy and spectroscopy reveal the inextricable role of surface electrochemistry in stabilizing and controlling ferroelectricity in doped hafnia.
Doped hafnia (HfO2), a relatively new member of the ferroelectric family, has challenged in many ways our conventional perception of ferroelectric oxides. It possesses extremely localized electric dipoles that are independently switchable,1 making it immune to finite size effects — the loss of long-range dipole order in ferroic materials due to size scaling. While polycrystalline grains and microstructures can yield lower polarization and poorer cycling behavior in canonical ferroelectrics such as Pb(Zr,Ti)O3 and BaTiO3, in …
Molecular Mechanisms Of Amyloid-Like Fibril Formation, 2023 New Jersey Institute of Technology
Molecular Mechanisms Of Amyloid-Like Fibril Formation, Sharareh Jalali
Dissertations
Proteins play a critical role in living systems by performing most of the functions inside cells. The latter is determined by the protein's three-dimensional structure when it is folded in its native state. However, under pathological conditions, proteins can misfold and aggregate, accounting for the formation of highly ordered insoluble assemblies known as amyloid fibrils. These assemblies are associated with diseases like Parkinson's and Alzheimer's. Strong evidence suggests that three mechanisms are critical for forming amyloid fibrils. These mechanisms are the nucleation of amyloid fibrils in solution (primary nucleation) as well as on the surface of existing fibrils (secondary nucleation) …
Exploring Topological Phonons In Different Length Scales: Microtubules And Acoustic Metamaterials, 2023 New Jersey Institute of Technology
Exploring Topological Phonons In Different Length Scales: Microtubules And Acoustic Metamaterials, Ssu-Ying Chen
Dissertations
The topological concepts of electronic states have been extended to phononic systems, leading to the prediction of topological phonons in a variety of materials. These phonons play a crucial role in determining material properties such as thermal conductivity, thermoelectricity, superconductivity, and specific heat. The objective of this dissertation is to investigate the role of topological phonons at different length scales.
Firstly, the acoustic resonator properties of tubulin proteins, which form microtubules, will be explored The microtubule has been proposed as an analog of a topological phononic insulator due to its unique properties. One key characteristic of topological materials is the …
Feasibility Of Functional Mri On Point-Of-Care Mr Platforms, 2023 Western University
Feasibility Of Functional Mri On Point-Of-Care Mr Platforms, Arjama Halder
Electronic Thesis and Dissertation Repository
Magnetic resonance imaging (MRI) has proven to be a clinically valuable tool that can produce anatomical and functional images with improved soft tissue contrast compared to other imaging modalities. There has recently been a surge in low- and mid-field scanners due to hardware developments and innovative acquisition techniques. These compact scanners are accessible, offer reduced siting requirements and can be made operational at a reduced cost.
This thesis aims to implement blood-oxygen-level-dependent (BOLD) resting-state functional MRI (fMRI) at such a mid-field point-of-care scanner. The availability of this technique can be beneficial to get neurological information in cases of traumatic brain …
Investigation Of Student Understanding Of Representations Of Probability Concepts In Quantum Mechanics, 2023 University of Maine
Investigation Of Student Understanding Of Representations Of Probability Concepts In Quantum Mechanics, William D. Riihiluoma
Electronic Theses and Dissertations
The ability to relate physical concepts and phenomena to multiple mathematical representations—and to move fluidly between these representations—is a critical outcome expected of physics instruction. In upper-division quantum mechanics, students must work with multiple symbolic notations, including some that they have not previously encountered. Thus, developing the ability to generate and translate expressions in these notations is of great importance, and the extent to which students can relate these expressions to physical quantities and phenomena is crucial to understand.
To investigate student understanding of the expressions used in these notations and the ways they relate, clinical think-aloud interviews were conducted …
Towards Clinical Microscopic Fractional Anisotropy Imaging, 2023 Western University
Towards Clinical Microscopic Fractional Anisotropy Imaging, Nico Jj Arezza
Electronic Thesis and Dissertation Repository
Microscopic fractional anisotropy (µFA) is a diffusion-weighted magnetic resonance imaging (dMRI) metric that is sensitive to neuron microstructural features without being confounded by the orientation dispersion of axons and dendrites. µFA may potentially act as a surrogate biomarker for neurodegeneration, demyelination, and other pathological changes to neuron microstructure with greater specificity than other dMRI techniques that are sensitive to orientation dispersion, such as diffusion tensor imaging. As with many advanced imaging techniques, µFA is primarily used in research studies and has not seen use in clinical settings.
The primary goal of this Thesis was to assess the clinical viability of …
Optimization Of A Ball's Launch In Sports, 2023 University of West Georgia
Optimization Of A Ball's Launch In Sports, Andrew C. Smith, Javier E. Hasbun
Georgia Journal of Science
Newton's laws are used to study the effects of air resistance on an object's motion. In ball-related sports such as baseball, soccer, etc., understanding the effects of air resistance is essential to optimize ball launch performance. This performance optimization can be studied by identifying the minimal time it takes for a ball with speed to travel a certain distance. We work with two models that apply to an object's motion. One of the models assumes a linear air drag while a second model makes use of a quadratic air drag. We do investigate known differential equations for when the Magnus …
Synthesis, Characterization, And Simulation Of Two-Dimensional Materials, 2023 University of Wisconsin-Milwaukee
Synthesis, Characterization, And Simulation Of Two-Dimensional Materials, Lawrence Hudy
Theses and Dissertations
ABSTRACT
SYNTHESIS, CHARACTERIZATION, AND SIMULATION OF TWO-DIMENSIONAL MATERIALS
by
Lawrence Hudy
The University of Wisconsin-Milwaukee, 2023Under the Supervision of Professor Michael Weinert
This dissertation focuses on my journey through many aspects of surface science leading to the first principles investigation of transition metal dichalcogenides studying the impact of defects, twist, and decreasing interlayer separation to probe their effect on the electronic properties of these materials. My journey started out learning many aspects of material science such as methods for material synthesis and characterization but later ended on simulation of material properties using density functional theory. In the first experiments, we …
Entanglement In The Hawking Effect: From Astrophysical To Optical Black Holes, 2023 Louisiana State University at Baton Rouge
Entanglement In The Hawking Effect: From Astrophysical To Optical Black Holes, Dimitrios Kranas
LSU Doctoral Dissertations
The Hawking effect is an exciting physical prediction lying at the intersection of the two most successful theories of the past century, namely, Einstein’s theory of relativity and quantum mechanics. In this dissertation, we put special emphasis on the quantum aspects of the Hawking process encoded in the entanglement shared by the emitted fluxes of created quanta. In particular, we employ sharp tools from quantum information theory to quantify the entanglement produced by the Hawking effect throughout the black hole evaporation process. Our framework allows us to extend previous calculations of entanglement to a larger set of cases, for instance, …
Adaptive Plasmonic Metasurfaces For Radiative Cooling And Passive Thermoregulation, 2023 Chapman University
Adaptive Plasmonic Metasurfaces For Radiative Cooling And Passive Thermoregulation, Azadeh Didari-Bader, Nooshin M. Estakhri, Nasim Mohammadi Estrakhri
Engineering Faculty Articles and Research
In this work, we investigate a class of planar photonic structures operating as passive thermoregulators. The radiative cooling process is adjusted through the incorporation of a phase change material (Vanadium Dioxide, VO2) in conjunction with a layer of transparent conductive oxide (Aluminum-doped Zinc Oxide, AZO). VO2 is known to undergo a phase transition from the “dielectric” phase to the “plasmonic” or “metallic” phase at a critical temperature close to 68°C. In addition, AZO shows plasmonic properties at the long-wave infrared spectrum, which, combined with VO2, provides a rich platform to achieve low reflections across the …
Optimizing Solid Thermal Storage In Insulated Solar Electric Cookers, 2023 California Polytechnic State University, San Luis Obispo
Optimizing Solid Thermal Storage In Insulated Solar Electric Cookers, Stefan Avramov
Physics
Insulated Solar Electric Cookers, more commonly known by their acronym ISECookers, are an alternative to biomass cooking. The ISECooker in its simplest form is a solar panel connected to a heating element, in contact with a cooking pot in an insulated chamber. An aluminum puck can be heated as solid thermal storage (STS) for increased power and night time cooking. Power was limited to about 500 W by the interface between the STS and cookpot. Powdered graphite and silver were separately applied to increase thermal flow. However, the powdered graphite decreased the thermal flow, while powdered silver decreased the temperature …
Characterization Of Boreal-Arctic Vegetation Growth Phases And Active Soil Layer Dynamics In The High-Latitudes Of North America: A Study Combining Multi-Year In Situ And Satellite-Based Observations, 2023 The Graduate Center, City University of New York
Characterization Of Boreal-Arctic Vegetation Growth Phases And Active Soil Layer Dynamics In The High-Latitudes Of North America: A Study Combining Multi-Year In Situ And Satellite-Based Observations, Michael G. Brown
Dissertations, Theses, and Capstone Projects
This dissertation examined the seasonal freeze/thaw activity in boreal-Arctic soils and vegetation physiology in Alaska, USA and Alberta, Canada, using in situ environmental measurements and passive microwave satellite observations. The boreal-Arctic high-latitudes have been experiencing ecosystem changes more rapidly in comparison to the rest of Earth due to the presently warming climatic conditions having a magnified effect over Polar Regions. Currently, the boreal-Arctic is a carbon sink; however, recent studies indicate a shift over the next century to become a carbon source. High-latitude vegetation and cold soil dynamics are influenced by climatic shifts and are largely responsible for the regions …
Experiments And Data Analysis For Modulated Phase Gratings In X-Rays, 2023 Louisiana State University and Agricultural and Mechanical College
Experiments And Data Analysis For Modulated Phase Gratings In X-Rays, Sydney B. Carr
LSU Master's Theses
Purpose: Modulated Phase Grating (MPG) interferometry has been shown in theory and simulations to produce observable fringes on a clinical detector without requiring fluence absorbing analyzer. In this work, we will experimentally show that the MPG X-ray system produces observable fringes and multi-modal X-ray images.
Motivation:Nearly 1 in 8 women in the US will develop invasive breast cancer in their lifetime, accounting for approximately 40,000 deaths each year [1-2]. In order to pursue the best treatment option available, cancer itself must be adequately imaged and staged, based on size and level of metastasis, on the order of Stage I-IV. …
Using Deep Neural Networks To Classify Astronomical Images, 2023 Seattle Pacific University
Using Deep Neural Networks To Classify Astronomical Images, Andrew D. Macpherson
Honors Projects
As the quantity of astronomical data available continues to exceed the resources available for analysis, recent advances in artificial intelligence encourage the development of automated classification tools. This paper lays out a framework for constructing a deep neural network capable of classifying individual astronomical images by describing techniques to extract and label these objects from large images.
The Future Is Now In Twisted Coil Polymer Actuators (Tcpa), 2023 Stephen F. Austin State University
The Future Is Now In Twisted Coil Polymer Actuators (Tcpa), Ryan Ronquillo
Electronic Theses and Dissertations
This thesis aimed to fabricate and test twisted coiled polymer actuators (TCPA) to understand the mechanical and thermal aspects of this artificial muscle fiber. The purpose of this thesis was to find a linear relationship using the LVDT sensor, fabricating TCPA fibers, and interpreting the data. The project tested whether nylon/polymer could be used as a better artificial muscle fiber.
This research accomplished three goals: (1) designing and fabricating a system capable of creating supercoiled muscle fibers consistently, (2) calibrating the Linear Variable Differential Transformer (LVDT) and Core, and (3) analyzing/interpreting the data of the Twisted Coiled Polymer Actuators (TCPA) …
Horizon Content Knowledge And Its Integration Into Physics Education Research: Case Study Analysis On Physical Science And Physics Teachers, 2023 The University of Maine
Horizon Content Knowledge And Its Integration Into Physics Education Research: Case Study Analysis On Physical Science And Physics Teachers, Trevor A. Robertson
Electronic Theses and Dissertations
Teachers focused on just one year of instruction may neglect what students need most– a coherent structure of learning across disciplines that advances students’ understanding. The topic of coherence has been a major motivator for education research, including investigations in student- teacher interactions, epistemological beliefs, and large-scale curricular reform. One framework of knowledge, horizon content knowledge (HCK), can aid in describing the knowledge a teacher needs to see beyond their own instruction and provide a coherent structure for students.
While horizon content knowledge exists in one of the most widely adopted teacher frameworks of knowledge in mathematics, mathematical knowledge for …
Domain Wall Saddle Point Morphology In Ferroelectric Triglycine Sulfate, 2023 Queen’s University Belfast
Domain Wall Saddle Point Morphology In Ferroelectric Triglycine Sulfate, C. J. Mccluskey, A. Kumar, Alexei Gruverman, I. Luk’Yanchuk, J. M. Gregg
Alexei Gruverman Publications
Ferroelectric domain walls, across which there is a divergence in polarization, usually have enhanced electrical conductivity relative to bulk. However, in lead germanate, head-to-head and tail-to-tail walls are electrically insulating. Recent studies have shown that this is because, when oppositely oriented domains meet, polar divergence is obviated by a combination of domain bifurcation and suspected local dipolar rotation. To explore the uniqueness, or otherwise, of this microstructure, we have used tomographic piezoresponse force microscopy to map three-dimensional domain morphologies in another uniaxial ferroelectric system: triglycine sulfate. This mapping reveals an abundance of domain wall saddle points, which are characteristic of …