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Articles 1591 - 1620 of 36535

Full-Text Articles in Physical Sciences and Mathematics

Using Machine Learning To Search For Vector Boson Scattering At The Cms Detector During Run 2, Mark Mekosh Jan 2023

Using Machine Learning To Search For Vector Boson Scattering At The Cms Detector During Run 2, Mark Mekosh

Graduate Research Theses & Dissertations

This work reports on the use of different machine learning (ML) techniques in the search for vector boson scattering (VBS) events in the semileptonic $WV$ channel. VBS is an important process for studying electroweak symmetry breaking (EWSB), the Higgs mechanism, as well as for probing beyond the standard model physics. Boosted decision trees as well as deep neural networks were trained on Monte Carlo simulation samples and applied to 137 fb$^{-1}$ of proton-proton collision data taken from 2016 to 2018 by the Compact Muon Solenoid (CMS) experiment at the Large Hadron Collider (LHC) with a center of mass energy $\sqrt{s} …


Simulations Of Electro-Optically Sampled Arbitrarily Shaped Electron Bunches For Wakefield Acceleratiors, Spencer Joseph Kelham Jan 2023

Simulations Of Electro-Optically Sampled Arbitrarily Shaped Electron Bunches For Wakefield Acceleratiors, Spencer Joseph Kelham

Graduate Research Theses & Dissertations

The measurement and recording of terahertz (THz) electric fields is of specialinterest to particle-accelerator science, as the electric fields of temporally short rela- tivistic electron bunches have frequency components that extend into the THz range. A single-shot, non-destructive measurement of such fields can be made using THz time-domain spectroscopy and electro-optic sampling. At the Argonne Wakefield Ac- celerator, arbitrary electron-bunch shapes are being explored to enhance the efficiency of advanced wakefield-accelerator schemes. In this report, we develop a framework for numerically modeling an implementation of electro-optical sampling – dubbed phase-diversity electro-optic sampling [1] – and apply the model to understand …


The Standard Model Precision Parameters At 200 Gev, Zamiul Alam Jan 2023

The Standard Model Precision Parameters At 200 Gev, Zamiul Alam

Graduate Research Theses & Dissertations

The Standard Model can be defined quantitatively by running parameters in a mass-independent renormalization scheme at a fixed reference scale. We provide a set of simple interpolation formulas that give the fundamental Lagrangian parameters in the MS-bar scheme at a renormalization scale of 200 GeV, safely above the top-quark mass and suitable for matching to candidate new physics models at very high mass scales using renormalization group equations. These interpolation formulas take as inputs the on-shell experimental quantities and use the best available calculations in the pure MS-bar scheme. They also serve as an accounting of the parametric uncertainties for …


Scalable Quantum Edge Detection Method For D-Nisq Imaging Simulations: Use Cases From Nuclear Physics And Medical Image Computing, Emmanuel Billias, Nikos Chrisochoides Jan 2023

Scalable Quantum Edge Detection Method For D-Nisq Imaging Simulations: Use Cases From Nuclear Physics And Medical Image Computing, Emmanuel Billias, Nikos Chrisochoides

The Graduate School Posters

Edge Detection is one of the computationally intensive modules in image analysis. It is used to find important landmarks by identifying a significant change (or “edge”) between pixels and voxels. We present a hybrid Quantum Edge Detection method by improving three aspects of an existing widely referenced implementation, which for our use cases generates incomprehensible results for the type and size of images we are required to process. Our contributions are in the pre- and post-processing (i.e., classical phase) and a quantum edge detection circuit: (1) we use space- filling curves to eliminate image artifacts introduced by the image decomposition, …


Nasa Student Launch - Payload, Eli Kirk Jan 2023

Nasa Student Launch - Payload, Eli Kirk

All Undergraduate Projects

A team of mechanical engineering, physics, and computer science students from Central Washington University have constructed a fully functional subscale model rocket to be flown at the NASA Student Launch competition. The rocket’s payload was designed to open the nose cone and take a photo of the rocket’s surroundings after descending from the launch. Smaller parts were constructed through machining and 3D printing that will be added to the purchased major component, the linear actuator, in order to perform the required tasks. These tasks are signaled by an attached electronics board, which will receive an RF command remotely, execute code, …


On The Gaussian-Core Vortex Lattice Model For The Analysis Of Wind Farm Flow Dynamics, Apurva Baruah Jan 2023

On The Gaussian-Core Vortex Lattice Model For The Analysis Of Wind Farm Flow Dynamics, Apurva Baruah

Dissertations, Master's Theses and Master's Reports

Wind power science has seen tremendous development and growth over the last 40 years. Advancements in design, manufacturing, installation, and operation of wind turbines have enabled the commercial deployment of wind power generation systems. These have been due, in a large part, to the expertise in the simulation and modeling of individual wind turbines. The new generation of wind energy systems calls for a need to accurately predict and model the entire wind farm, and not just individual turbines. The commercial deployment of these wind farms depends on model's ability to accurately capture the different physics involved, each at its …


Development Of Novel Hpge Detector For Rare Event Physics, Mathbar Singh Raut Jan 2023

Development Of Novel Hpge Detector For Rare Event Physics, Mathbar Singh Raut

Dissertations and Theses

This dissertation focuses on the enhancement of crystal quality in High Purity Germanium (HPGe) detectors, which play a crucial role in rare-event physics investigations such as dark matter detection, neutrinoless double-beta decay, geo-neutrinos, and solar neutrinos. The primary objective of this research is to improve crystal quality by controlling impurity concentration, dislocation density, and growth environment. Additionally, the development of advanced Ge detectors for various physics applications is explored. One significant aspect examined in this dissertation is the investigation of systematic errors associated with the Hall effect system. The goal is to identify a reliable technique that minimizes the systematic …


Background Discrimination Of A Neutrino Detector With Dense Neural Networks, Perry Siehien Jan 2023

Background Discrimination Of A Neutrino Detector With Dense Neural Networks, Perry Siehien

Dissertations and Theses

Neutrinos are subatomic particles that weakly interact with matter due to their neutral charge and small cross section. Detectors that search for neutrinos require sensitive instrumentation, which makes them susceptible to various background sources such as gamma rays. Additionally, coherent elastic neutrino-nucleus scattering events, or CEvNS, are the weakest neutrino interactions at 1-25 keV, making them exceptionally difficult to observe. To understand the physics of CEvNS events within the detector material, the recoil signatures of relevant interactions must be determined. Traditional analysis methods are effective, but cannot be applied to energies below 50 keV, due to the overlap of discrimination …


Homopurine Guanine-Rich Sequences In Complex With N-Methyl Mesoporphyrin Ix Form Parallel G-Quadruplex Dimers And Display A Unique Symmetry Tetrad, Ming Ye, Erin V. Chen, Shawn H. Pfeil, Kailey N. Martin, Tamanaa Atrafi, Sara Yun, Zahara Martinez, Liliya A. Yatsunyk Jan 2023

Homopurine Guanine-Rich Sequences In Complex With N-Methyl Mesoporphyrin Ix Form Parallel G-Quadruplex Dimers And Display A Unique Symmetry Tetrad, Ming Ye, Erin V. Chen, Shawn H. Pfeil, Kailey N. Martin, Tamanaa Atrafi, Sara Yun, Zahara Martinez, Liliya A. Yatsunyk

Physics & Engineering Faculty Publications

DNA can fold into G-quadruplexes (GQs), non-canonical secondary structures formed by pi-pi stacking of G-tet-rads. GQs are important in many biological processes, which makes them promising therapeutic targets. We identified a 42-nucleotide long, purine-only G-rich sequence from human genome, which contains eight G- stretches connected by A and AAAA loops. We divided this sequence into five unique segments, four guanine stretches each, named GA1-5. In order to investigate the role of adenines in GQ structure formation, we per-formed biophysical and X-ray crystallographic studies of GA1-5 and their complexes with a highly selective GQ ligand, N-methyl mesoporphyrin IX (NMM). Our data …


Investigating The Structural Properties Of Licoo2 Through Annealing In A Reducing Atmosphere And Characterization Using Raman Spectroscopy And X-Ray Diffraction, Mathew A. Boeser Jan 2023

Investigating The Structural Properties Of Licoo2 Through Annealing In A Reducing Atmosphere And Characterization Using Raman Spectroscopy And X-Ray Diffraction, Mathew A. Boeser

MSU Graduate Theses

The electrochemical performance of lithium cobalt oxide (LiCoO2) cathode materials in lithium-ion batteries is strongly influenced by their structural and chemical characteristics. Annealing in a reducing atmosphere is able to modify the crystal structure of LiCoO2 by inducing oxygen vacancies, ideally enhancing its electrochemical performance. This master's thesis presents an investigation into the effects of low to mid-range annealing temperatures in a reducing atmosphere on bulk LiCoO2 powder, utilizing Raman spectroscopy and X-ray Diffraction (XRD).


Evaluation Of The Photon Contributions To The Solar Energy Conversion For Organic Luminescent Down-Shifting Liquid Beam Splitters In Hybrid Photovoltaic-Thermal (Pvt) Applications Using Raytracing Monte Carlo Simulations, Kenneth Coldrick Jan 2023

Evaluation Of The Photon Contributions To The Solar Energy Conversion For Organic Luminescent Down-Shifting Liquid Beam Splitters In Hybrid Photovoltaic-Thermal (Pvt) Applications Using Raytracing Monte Carlo Simulations, Kenneth Coldrick

Articles

A hybrid photovoltaic-thermal (PVT) system combines photovoltaic (PV) and photo-thermal (PT) energy collection into a single structure, enhancing the potential to achieve greater solar energy conversion efficiencies. Such enhanced efficiencies can result in greater economic returns and could promote a larger uptake of PVT devices in cold and temperate climate countries. Through the utilization of a Monte Carlo ray-tracing model, this work provides new insights into the optical, electrical, and thermal characteristics of PVT devices. In particular, the work focuses on evaluating the behaviour of novel luminescent imidazole-phenanthroline-based working fluids that were previously experimentally investigated as liquid spectral beam splitters …


The Employees’ Perspective: Situational Leadership Style Flexibility And Effectiveness And Employee Performance In A Technological Organization, Merari Cortes Jan 2023

The Employees’ Perspective: Situational Leadership Style Flexibility And Effectiveness And Employee Performance In A Technological Organization, Merari Cortes

Walden Dissertations and Doctoral Studies

Poor employee performance can have adverse effects on business outcomes. Business leaders are concerned with poor performance, which can minimize profitability and negatively impact business sustainability. Grounded in the Situational Leadership II® model, the purpose of this quantitative correlational study was to examine the relationship between situational leadership style flexibility, effectiveness, and employee performance as perceived by employees, controlling for employee gender, job location, and tenure. A random sample of 99 technology company employees completed the Leader Behavior Analysis II®– Other and the Employee Job Performance measurement tools. Using hierarchical multilinear regression, employee gender, job location, and tenure were entered …


Review-Electrode Kinetics And Electrolyte Stability In Vanadium Flow Batteries, Andrea Bourke, Daniela Oboroceanu, Nathan Quill, Catherine Lenihan, Maria Alhajji Safi Maria Alhajji Safi, Mallory A. Miller, Robert F. Savinell, Jesse S. Wainright, Varsha Sasikumarsp, Maria Rybalchenko, Pupak Amini, Niall Dalton, Robert P. Lynch, D. Noel Buckley Jan 2023

Review-Electrode Kinetics And Electrolyte Stability In Vanadium Flow Batteries, Andrea Bourke, Daniela Oboroceanu, Nathan Quill, Catherine Lenihan, Maria Alhajji Safi Maria Alhajji Safi, Mallory A. Miller, Robert F. Savinell, Jesse S. Wainright, Varsha Sasikumarsp, Maria Rybalchenko, Pupak Amini, Niall Dalton, Robert P. Lynch, D. Noel Buckley

Articles

Two aspects of vanadium flow batteries are reviewed: electrochemical kinetics on carbon electrodes and positive electrolyte stability. There is poor agreement between reported values of kinetic parameters; however, most authors report that kinetic rates are faster for VIV/VV than for VII/VIII. Cycling the electrode potential increases the rates of both reactions initially due to roughening but when no further roughening is observed, the VII/VIII and VIV/VV reactions are affected oppositely by the pretreatment potential. Anodic pretreatment activates the electrode for the VII/VIII reaction, and deactivates it for VIV/VV. Three states of the carbon surface are suggested: reduced and oxidized states …


The Future Between Quantum Computing And Cybersecurity, Daniel Dorazio Jan 2023

The Future Between Quantum Computing And Cybersecurity, Daniel Dorazio

Williams Honors College, Honors Research Projects

Quantum computing, a novel branch of technology based on quantum theory, processes information in ways beyond the capabilities of classical computers. Traditional computers use binary digits [bits], but quantum computers use quantum binary digits [qubits] that can exist in multiple states simultaneously. Since developing the first two-qubit quantum computer in 1998, the quantum computing field has experienced rapid growth.

Cryptographic algorithms such as RSA and ECC, essential for internet security, rely on the difficulty of complex math problems that classical computers can’t solve. However, the advancement of quantum technology threatens these encryption systems. Algorithms, such as Shor’s, leverage the power …


Energy Conversion In Plasmas Out Of Local Thermodynamic Equilibrium: A Kinetic Theory Perspective, Mahmud Hasan Barbhuiya Jan 2023

Energy Conversion In Plasmas Out Of Local Thermodynamic Equilibrium: A Kinetic Theory Perspective, Mahmud Hasan Barbhuiya

Graduate Theses, Dissertations, and Problem Reports

The study of energy conversion in collisionless plasmas that are not in local thermodynamic equilibrium (LTE) is at the leading edge of plasma physics research. Plasma constituents in such systems can exhibit highly structured phase space densities that deviate significantly from that of a Maxwellian. A standard approach has emerged in recent years for investigating energy conversion between bulk flow and thermal energy in collisionless plasmas using the non-LTE generalization of the first law of thermodynamics. The primary focus is placed on pressure-strain interaction (PS) term, with a particular emphasis on its non-LTE piece called Pi − D. Recent studies …


Strong Homotopy Lie Algebras And Hypergraphs, Samuel J. Bevins, Marco Aldi Jan 2023

Strong Homotopy Lie Algebras And Hypergraphs, Samuel J. Bevins, Marco Aldi

Undergraduate Research Posters

We study hypergraphs by attaching a nilpotent strong homotopy Lie algebra. We especially focus on hypergraph theoretic information that is encoded in the cohomology of the resulting strong homotopy Lie algebra.


Gamelan Gong Directivity Dataset, Samuel D. Bellows, Dallin T. Harwood, Kent L. Gee, Micah R. Shepherd Jan 2023

Gamelan Gong Directivity Dataset, Samuel D. Bellows, Dallin T. Harwood, Kent L. Gee, Micah R. Shepherd

Directivity

No abstract provided.


Examining The Feasibility Of Identifying Tau Neutrino Charged Current Events In The Dune Far Detector, Sarah Choate Jan 2023

Examining The Feasibility Of Identifying Tau Neutrino Charged Current Events In The Dune Far Detector, Sarah Choate

Graduate Research Theses & Dissertations

Neutrinos began as theoretical, massless particles, and since their first detection they have continued to be the subject of various experiments. One such experiment is DUNE, which is a long baseline neutrino experiment with the goal of studying neutrino properties, such as neutrino oscillation parameters. In this work, two projects were completed, one dealing with the hardware of DUNE and the other dealing with neutrino simulations. For the hardware project, we designed a quality control method for testing adaptor boards which make up part of the Far Detector circuit boards. This method was completed and prototyped, however was not implemented …


Study Of The Dynamics Of Glasses Using Nuclear Resonance Time Domain Interferometry, Marc Pavlik Jan 2023

Study Of The Dynamics Of Glasses Using Nuclear Resonance Time Domain Interferometry, Marc Pavlik

Graduate Research Theses & Dissertations

Nuclear resonance time domain interferometry (NR-TDI) is used to study the slow dy- namics of liquids (that do not require M ̈ossbauer isotopes) at atomic and molecular length scales between 1 A to 10 nm and at time scales between 1 ns to 10 μs. This new spectroscopy technique covers a new range of previously unexplored momentum transfers between 1 to 100 nm−1 and energies between 10 peV to 100 neV allowing an investigation into the dynami- cal motion of molecules, liquids, and glasses. The notoriously low count rate from quasielastic scattering experiments makes measurements difficult when using synchrotron x-rays …


Switchable Anomalous Hall Effects In Polar-Stacked 2d Antiferromagnet Mnbi2Te4, Tengfei Cao, Ding-Fu Shao, Kai Huang, Gautam Gurung, Evgeny Y. Tsymbal Jan 2023

Switchable Anomalous Hall Effects In Polar-Stacked 2d Antiferromagnet Mnbi2Te4, Tengfei Cao, Ding-Fu Shao, Kai Huang, Gautam Gurung, Evgeny Y. Tsymbal

Department of Physics and Astronomy: Faculty Publications

Van der Waals (vdW) assembly allows controlling symmetry of two-dimensional (2D) materials that determines their physical properties. Especially interesting is the recently demonstrated breaking inversion symmetry by polar layer stacking to realize novel electronic, magnetic, and transport properties of 2D vdW materials switchable by induced electric polarization. Here, based on symmetry analyses and density-functional calculations, we explore the emergence of the anomalous Hall effect (AHE) in antiferromagnetic MnBi2Te4 films assembled by polar layer stacking. We demonstrate that breaking 𝑃̂ 𝑇̂ symmetry in an MnBi2Te4 bilayer makes this 2D material magnetoelectric and produces a spontaneous AHE switchable by …


Anisotropic Optical And Magnetic Response In Self-Assembled Tin-Cofe2 Nanocomposites, Jiawei Song, Di Zhang, Ping Lu, Haohan Wang, X. S. Xu, Melissa L. Meyerson, Samantha G. Rosenberg, Julia Deitz, Juncheng Liu, Xuejing Wang, Xinghang Zhang Jan 2023

Anisotropic Optical And Magnetic Response In Self-Assembled Tin-Cofe2 Nanocomposites, Jiawei Song, Di Zhang, Ping Lu, Haohan Wang, X. S. Xu, Melissa L. Meyerson, Samantha G. Rosenberg, Julia Deitz, Juncheng Liu, Xuejing Wang, Xinghang Zhang

Department of Physics and Astronomy: Faculty Publications

Transition metal nitrides (e.g., TiN) have shown tremendous promise in optical metamaterials for nanophotonic devices due to their plasmonic properties comparable to noble metals and superior high temperature stability. Vertically aligned nanocomposites (VANs) offer a great platform for combining two dissimilar functional materials with a one-step deposition technique toward multifunctionality integration and strong structural/property anisotropy. Here we report a two-phase nanocomposite design combining ferromagnetic CoFe2 nanosheets in the plasmonic TiN matrix as a new hybrid plasmonic metamaterial. The hybrid metamaterials exhibit obvious anisotropic optical and magnetic responses, as well as a pronounced magneto-optical coupling response evidenced by MOKE measurement, …


Interface-Tuning Of Ferroelectricity And Quadruple-Well State In Cuinp2S6 Via Ferroelectric Oxide, Kun Wang, Du Li, Jia Wang, Yifei Hao, Hailey Anderson, Li Yang, Xia Hong Jan 2023

Interface-Tuning Of Ferroelectricity And Quadruple-Well State In Cuinp2S6 Via Ferroelectric Oxide, Kun Wang, Du Li, Jia Wang, Yifei Hao, Hailey Anderson, Li Yang, Xia Hong

Department of Physics and Astronomy: Faculty Publications

Ferroelectric van der Waals CuInP2S6 possesses intriguing quadruple-well states and negative piezoelectricity. Its technological implementation has been impeded by the relatively low Curie temperature (bulk TC ~42 °C) and the lack of precise domain control. Here we show that CuInP2S6 can be immune to the finite size effect and exhibits enhanced ferroelectricity, piezoelectricity, and polar alignment in the ultrathin limit when interfaced with ferroelectric oxide PbZr0.2Ti0.8O3 films. Piezoresponse force microscopy studies reveal that the polar domains in thin CuInP2S6 fully conform to those of underlying …


From Sine Waves To Soundscapes: Exploring The Art And Science Of Analog Synthesizer Design, Saiqi Zhang Jan 2023

From Sine Waves To Soundscapes: Exploring The Art And Science Of Analog Synthesizer Design, Saiqi Zhang

Senior Projects Spring 2023

Senior Project submitted to The Division of Science, Mathematics and Computing of Bard College.


Theoretical Foundations Of Quantum Computing And The Implementation Of The Quantum Fourier Transform, Natalia Dziubelski Jan 2023

Theoretical Foundations Of Quantum Computing And The Implementation Of The Quantum Fourier Transform, Natalia Dziubelski

Senior Projects Spring 2023

Quantum computing is a growing field with the potential to revolutionize computation. This thesis explores the foundations of quantum computing with specific focus on the efficacy of the Quantum Fourier Transform (QFT). The fundamentals of quantum computing were described through an explanation of quantum mechanics and the mathematics needed to understand the quantum computing model and its operations. Using IBM’s simulators and quantum processors, the QFT was implemented on a classical data set, and the results were compared to the predicted output values. It was found that the QFT simulator was able to produce results consistent with Discrete Fourier Transform, …


Compiling Quantum Programs, Li-Heng Henry Chang Jan 2023

Compiling Quantum Programs, Li-Heng Henry Chang

Senior Projects Spring 2023

This thesis introduces the quantum compilation problem and develops a prototypical compiler. The problem of quantum compiling is, in essence, converting high-level human expressions of quantum programs into low-level hardware executable code. Compilers that target different hardware platforms enable portable code that can be used to benchmark hardware performance, reduce programming work and speed up development. Because quantum systems are subjected to phenomena such as noise, no-cloning and decoherence, the challenge of quantum compiling is tied to the optimization of program runtimes and the lengths of compiled sequences. For near-term intermediate scale quantum (NISQ) computers with limited hardware resources and …


Acceptable Title Pending: Probing The Limits Of Precision Measurement And Academic Assessment, Bobby King Jan 2023

Acceptable Title Pending: Probing The Limits Of Precision Measurement And Academic Assessment, Bobby King

Senior Projects Spring 2023

This is a project in two parts. The first is an attempt to impart onto the reader the necessary mental models required to understand a scientific experiment related to the improvement of gravitational wave detectors. Part one is illustrated in collaboration with Simone River Wilding, Sohpie Foley, Roma Taitwood, and Cam Goldberg.

Part two is a technical description of efforts made to reduce speckle in measurements of scattered light. Gravitational wave detection requires extremely high precision measurement, and one source of noise in the detectors is scattering off of defects and surface roughness in optical coatings. Research into the development …


Detailed Analysis Of The Tev Γ-Ray Sources 3hwc J1928+178, 3hwc J1930+188, And The New Source Hawc J1932+192, A. Albert, R. Alfaro, C. Alvarez, J. C. Arteaga-Velázquez, D. Avila Rojas, H. A.Ayala Solares, R. Babu, D. Huang, P. Hüntemeyer, R. Turner, X. Wang, Et Al. Jan 2023

Detailed Analysis Of The Tev Γ-Ray Sources 3hwc J1928+178, 3hwc J1930+188, And The New Source Hawc J1932+192, A. Albert, R. Alfaro, C. Alvarez, J. C. Arteaga-Velázquez, D. Avila Rojas, H. A.Ayala Solares, R. Babu, D. Huang, P. Hüntemeyer, R. Turner, X. Wang, Et Al.

Michigan Tech Publications

The latest High Altitude Water Cherenkov (HAWC) point-like source catalog up to 56 TeV reported the detection of two sources in the region of the Galactic plane at galactic longitude 52° < ℓ < 55°, 3HWC J1930+188 and 3HWC J1928+178. The first one is associated with a known TeV source, the supernova remnant SNR G054.1+00.3. It was discovered by one of the currently operating Imaging Atmospheric Cherenkov Telescope (IACT), the Very Energetic Radiation Imaging Telescope Array System (VERITAS), detected by the High Energy Stereoscopic System (H.E.S.S), and identified as a composite SNR. However, the source 3HWC J1928+178, discovered by HAWC and coincident with the pulsar PSR J1928+1746, was not detected by any IACT despite their long exposure on the region, until a recent new analysis of H.E.S.S. data was able to confirm it. Moreover, no X-ray counterpart has been detected from this pulsar. We present a multicomponent fit of this region using the latest HAWC data. This reveals an additional new source, HAWC J1932+192, which is potentially associated with the pulsar PSR J1932+1916, whose γ-ray emission could come from the acceleration of particles in its pulsar wind nebula. In the case of 3HWC J1928+178, several possible explanations are explored, in an attempt to unveil the origins of the very-high-energy γ-ray emission.


High Energy Blue Light Induces Oxidative Stress And Retinal Cell Apoptosis, Jessica Malinsky Jan 2023

High Energy Blue Light Induces Oxidative Stress And Retinal Cell Apoptosis, Jessica Malinsky

Capstone Showcase

Blue light (BL) is a high energy, short wavelength spanning 400 to 500 nm. Found in technological and environmental forms, BL has been shown to induce photochemical damage of the retina by reactive oxygen species (ROS) production. Excess ROS leads to oxidative stress, which disrupts retinal mitochondrial structure and function. As mitochondria amply occupy photoreceptors, they also contribute to oxidative stress due to their selectively significant absorption of BL at 400 to 500 nm. ROS generation that induces oxidative stress subsequently promotes retinal mitochondrial apoptosis. BL filtering and preventative mechanisms have been suggested to improve or repair BL-induced retinal damage, …


Novel Compact Magnetless Isolator Based On A Magneto-Optical Garnet Material, Gianni Portela, Miguel Levy, Hugo E. Hernandez-Figueroa Jan 2023

Novel Compact Magnetless Isolator Based On A Magneto-Optical Garnet Material, Gianni Portela, Miguel Levy, Hugo E. Hernandez-Figueroa

Michigan Tech Publications

A compact magnetless isolator for optical communication systems based on a ring resonator with an outer layer made of silicon and an inner layer made of a magneto-optical material that does not require an external magnet to keep its magnetization saturated is suggested. Three-dimensional computational simulations of the device performed with the full-wave electromagnetic solver COMSOL Multiphysics show that the insertion loss and isolation levels are about −1.9 dB and −23 dB, respectively, thus confirming the feasibility of the isolator. An analytical model of the device based on the temporal coupled-mode theory method has been formulated and there is a …


The Behavior Of Partially Coherent Twisted Space-Time Beams In Atmospheric Turbulence, Milo W. Hyde Iv Jan 2023

The Behavior Of Partially Coherent Twisted Space-Time Beams In Atmospheric Turbulence, Milo W. Hyde Iv

Faculty Publications

We study how atmospheric turbulence affects twisted space-time beams, which are non-stationary random optical fields whose space and time dimensions are coupled with a stochastic twist. Applying the extended Huygens–Fresnel principle, we derive the mutual coherence function of a twisted space-time beam after propagating a distance z through atmospheric turbulence of arbitrary strength. We specialize the result to derive the ensemble-averaged irradiance and discuss how turbulence affects the beam’s spatial size, pulse width, and space-time twist. Lastly, we generate, in simulation, twisted space-time beam field realizations and propagate them through atmospheric phase screens to validate our analysis.