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Porous Silicon Photonics For Label-Free Interferometric Biosensing And Flat Optics, Tahmid Hassan Talukdar

All Dissertations

This dissertation uses porous silicon as a material platform to explore novel optical effects in three domains: (i) It studies dispersion engineering in integrated waveguides to achieve high performance group index sensing. With proper design parameters, the sensor waveguides can theoretically achieve 6 times larger group index shift compared to the actual bulk effective refractive index shift. We demonstrate the guided mode confinement factor to be a key parameter in design and implementation of these waveguides. (ii) It explores multicolor laser illumination to experimentally demonstrate perceptually enhanced colorimetric sensing, overcoming the limitations faced by many contemporary colorimetric sensors. Our technique …

A Cross Section Measurement Of Muon Neutrino-Induced Charged-Current Coherent Positive Pion Production On Argon With The Microboone Detector, Zachary Glenn Randell Williams

Physics Dissertations - Archive

Neutrino-induced charged-current coherent pion production is an important channel for the study of neutrino-nucleus interactions. It is both a dangerous background for $\nu_{e}$ oscillation experiments, and a critical component required for precise understanding of neutrino-nucleus pion production in general. This work performed a search for $\nu_{\mu}$-induced charged-current (CC) coherent pion production on argon in MicroBooNE from Fermilab's Booster Neutrino Beamline (BNB), which produces $\nu_{\mu}$ with a mean energy of 0.823 GeV. A flux-integrated cross section measurement was made for this channel, and was found to be: $\sigma(\nu_{\mu} + Ar \rightarrow \mu^{-} + \pi^{+} + Ar) = 1.12 \pm 0.253 \textrm{(stat.)} …

Investigating Gluonic Operators In Coordinate Space, Wayne Henry Morris Iii

Physics Theses & Dissertations

In this dissertation, a method of extracting gluon momentum distributions inside hadrons, and particularly nucleons, is developed. In general, the utility and application of performing calculations in coordinate space at the operator level is discussed, and its application to the method of pseudodistributions in the lattice extraction of parton distributions. An introduction to the background field method and other techniques used in the calculation of corrections to gluon operators are provided. Then, an outline of the calculation of the uncontracted gluon bilocal operator at one-loop is given, and the result thereof. Using the result for the gluon bilocal operator restricted …

Studies Of Bonus12 Radial Gem Detector And Tcs Beam Spin Asymmetry In Clas12, Jiwan Poudel

Physics Theses & Dissertations

The Barely Offshell Nucleon Structure (BONuS12) experiment adopted the concept of spectator tagging technique to study the nearly-free neutron structure function F2n in the CLAS12 of Jefferson Lab. A novel Radial Time Projection Chamber (RTPC) detector was built, tested and integrated into the CLAS12 system to detect a back-moving low momentum tagged proton in d(e, ep)X deep-inelastic scattering. It was a 40 cm long gaseous detector consisting of 3 layers of cylindrical GEM foils for the charge amplification, with the data readout directly from the surrounding padboard. The RTPC detected the recoiling spectator proton, in coincidence with …

The Impact Of Sea-Level Rise In Numerically Modeled Landfalling Hurricanes: Katrina And The Gulf Coast., Serenity Nadirah Mercuri

Electronic Theses and Dissertations

With climate change, landfalling hurricanes become an increasing threat to coastal regions. However, the interactions between the coastal landscape and landfalling hurricanes are often overlooked when addressing sea-level rise outside of inundation and independent of sea surface temperature. This study analyzed the potential impacts regarding structure and intensity as a result of sea-level rise in the Gulf of Mexico using the WRF-ARW numerical model coupled with a 1D ocean model. Analysis showed that 10 m windspeed from landfall forward was higher in modified coastlines, and minimum sea-level pressure post-landfall was consistently lower for modified runs where storms maintain a higher …

Optimization Of Modular, Long-Range, Ultra-Fast Optical Tweezers With Fluorescence Capabilities For Single-Molecule And Single-Cell Based Biophysical Measurements, Subash C. Godar

All Dissertations

An Optical tweezer is a tightly focused laser beam that applies and senses precise and localized optical force to a dielectric microsphere and offers a unique and effective tool for manipulating the single cell or cell components, including nucleotides and dynein motor proteins. Here, I used highly stabilized optomechanical components and ultra-sensitive detection modules to significantly improve the measurement capabilities over a wide range of temporal and spatial scales. I combined the optical tweezer-based force spectroscopy technique with fluorescence microscopy to develop an integrated high-resolution force-fluorescence system capable of measuring displacements at sub-nanometer, forces at sub-piconewton over a temporal range …

Exploring Tunable Magnetization And High-Temperature Ferromagnetism In Ternary Transition Metal-Based Chalcogenides, Hector Iturriaga

Open Access Theses & Dissertations

The discovery of long-range magnetic ordering in ultrathin transition metal-based compounds shows great promise for the development of nanoscale memory and spintronic devices. Composed of cost-effective materials and boasting from strong chemical and thermal stability at low dimensions, van der Waals (vdW) ternary transition metal chalcogenide magnets like CrSiTe3 (CST), Fe2.7GeTe2 (FGT), and Mn3Si2Te6 (MST), provide not only possible energy solutions, but also a broad platform to explore the versatile magnetic character of this family of compounds. Although they have great potential, it has been found that their long-range magnetic ordering exists at temperatures far too low (the highest of …

Low-Lying Spin-Flip Excitonic States Of ����12��12 (��������)16 [��2��]4 Molecule (Mn12 − ����), Karma Dema

Open Access Theses & Dissertations

Molecules and materials constructed from Mn atoms offer diverse assortments of geomet- rical and spin structures. The diversity of structures, in comparison with other transition metals, along with nature’s decision to use a Mn-based molecule to catalyze solar-driven water splitting and oxygen evolution, suggests that there is indeed something special about the location of Mn valence electrons, both energetically and geometrically, that endows Mn with its multifaceted behaviors that, in turn, provide such chemical, physical and mag- netic diversity. Based upon recent work on the Mn3 monomer and the Mn(taa) there is an expectation that Mn�� �� �� centers can …

Evolution Of The Magnetic Properties On Van Der Waals Layered Magnets Via Pressure And Proton Irradiation, Rubyann Olmos

Open Access Theses & Dissertations

Probing the magnetism in quasi two-dimensional materials has the potential in driving their properties towards future use in spin electronic based devices. Studying such layered magnets will enable the scientific community to uncover tunable exotic phases such as superconductivity, quantum paramagnetism, etc. This work examines the influence of two types of external perturbations, namely, the pressure and proton irradiation, on the magnetic properties of several compounds in the van der Waals crystal family.

Pressure has been found to induce structural and magnetic phase transitions in many of these materials. Using hydrostatic pressure as a disorderless approach to manipulate the interlayer …

Yang-Mills Sources In Biconformal Double Field Theory, Davis W. Muhwezi

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

There is a robust and unifying approach to unraveling the roiling mysteries of the universe. Our most compelling accounts of physical reality at present rest on symmetry arguments that are conspicuously geometrical!

105 years ago, Albert Einstein derived gravity from Riemannian geometry. In the general theory of relativity, the world of our experience is a pseudo-Riemannian manifold whose curvature represents the gravitational field. Encoded in the Einstein field equation is how matter sources (energy-momentum tensor) couple to gravity (spacetime curvature). Schematically, the Einstein equation exhibits a more general structure:

Curvature of Spacetime = Material Sources

On one side of the …

Exploring The Glow Of The Universe In Gamma-Rays And Hunting Distant Agn, Changam Meenakshi Rajagopal

All Dissertations

The entirety of the γ-ray radiation permeating our Universe is encoded in the extragalactic γ-ray background. This is a superposition of resolved sources, mostly powerful relativistic jets powered by supermassive black holes, i.e., blazars, and an unresolved isotropic component, aka, the diffuse isotropic gamma-ray background (IGRB). Studying the IGRB can help unveil its composition, as well as unearth multi-messenger relationships between the intensities of PeV neutrinos, ultra high energy cosmic rays (> 1018 eV), and sub-TeV γ-rays. The comparable energy budgets of these three phenomena (neutrinos, UHECR, and γ-rays) indicates a physical connection or a common source amongst them. On …

Supertertiary Structural Dynamics Modulate Function In Postsynaptic Density Protein 95, George L. Hamilton Iii

All Dissertations

Proteins, RNA, and DNA serve as the primary sub-cellular machinery that give rise to the necessary functions of life. The long-standing paradigm has been that the structures of biomolecules, or the arrangement of the subunits that make up a biomolecule, determine biological function. However, biomolecules are not static objects. Instead, they often undergo structural rearrangements that are crucial to enabling and regulating their functions. In my thesis I present several studies of the interplay between the structures, dynamics, and functions of biomolecules that combine experimental fluorescence spectroscopy and computational methods to probe these systems at the single-molecule level. In particular, …

Combining Pharmacokinetics And Vibrational Spectroscopy: Mcr-Als Hard-And-Soft Modelling Of Drug Uptake In Vitro Using Tailored Kinetic Constraints, David Perez-Guaita, Guillermo Quintas, Zeineb Farhane, Roma Tauler, Hugh Byrne

Articles

Raman microspectroscopy is a label-free technique which is very suited for the investigation of pharmacokinetics of cellular uptake, mechanisms of interaction, and efficacies of drugs in vitro. However, the complexity of the spectra makes the identification of spectral patterns associated with the drug and subsequent cellular responses difficult. Indeed, multivariate methods that relate spectral features to the inoculation time do not normally take into account the kinetics involved, and important theoretical information which could assist in the elucidation of the relevant spectral signatures is excluded. Here, we propose the integration of kinetic equations in the modelling of drug uptake and …

Objective Crystallographic Symmetry Classifications Of A Noisy Crystal Pattern With Strong Fedorov-Type Pseudo­Symmetries And Its Optimal Image-Quality Enhancement, Peter Moeck

Physics Faculty Publications and Presentations

Statistically sound crystallographic symmetry classifications are obtained with information-theory-based methods in the presence of approximately Gaussian distributed noise. A set of three synthetic patterns with strong Fedorov-type pseudo­symmetries and varying amounts of noise serve as examples. Contrary to traditional crystallographic symmetry classifications with an image processing program such as CRISP, the classification process does not need to be supervised by a human being and is free of any subjectively set thresholds in the geometric model selection process. This enables crystallographic symmetry classification of digital images that are more or less periodic in two dimensions (2D), also known as crystal …

Experimental Investigation Of All-Optical Production Of Metastable Krypton, Joshua Carl Frechem

Physics Theses & Dissertations

Metastable production of noble gases requires significant energy due to their filled valence shells. These transitions from the ground state are in the vacuum ultraviolet and extreme ultraviolet, which are relatively inaccessible to lasers. This necessitates the use of either electron/ion bombardment via inefficient glow discharges or the use of high-power lasers and nonlinear processes. The all-optical production efficiency using these high-power lasers promises to be orders of magnitude higher than glow discharges, but far more costly. This work looks to improve all-optical production of metastable krypton (Kr*) through the use of a commercially available vacuum ultraviolet lamp with a …

Ion Production And Mitigation In Dc High-Voltage Photo-Guns, Joshua T. Yoskowitz

Physics Theses & Dissertations

One of the biggest obstacles to operating a GaAs polarized electron source with a long charge lifetime is the mitigation of ion back-bombardment. Several techniques exist to either clear ions from the accelerator or to mitigate ion damage of the photocathode. Predicting the effectiveness of these techniques requires sophisticated simulation models of electron impact ionization within the photo-gun. In this work, the effectiveness of applying a positive anode bias voltage to mitigate ion damage and increase the charge lifetime of the GaAs photocathode was studied over three run periods at the Continuous Electron Beam Accelerator Facility (CEBAF) at Jefferson Lab …

Design & Analysis Of Mixed-Mode Integrated Circuit For Pulse-Shape Discrimination, Bryan Orabutt

McKelvey School of Engineering Graduate Student Theses & Dissertations

In nuclear science experiments it is usually necessary to determine the type of radiation, its energy and direction with considerable accuracy. The detection of neutrons and discriminating them from gamma rays is particularly difficult. A popular method of doing so is to measure characteristics intrinsic to the pulse shape of each radiation type in order to perform pulse-shape discrimination (PSD).

Historically, PSD capable systems have been designed with two approaches in mind: specialized analog circuitry, or digital signal processing (DSP). In this work we propose a PSD capable circuit topology using techniques from both the analog and DSP domains. We …

Terrestrial Planet Formation In M-Dwarf And Binary Star Systems, Anna C. Childs

UNLV Theses, Dissertations, Professional Papers, and Capstones

I examine circumbinary terrestrial planet formation in a gas free environment around various binary systems and terrestrial planet formation in a gaseous environment around M-dwarfs. While terrestrial cirumbinary planets have yet to be observed, this is likely due to observational bias. Motivated by recent observations of highly misaligned circumbinary gas disks, I perform a suite of n-body studies to understand the properties of terrestrial planets around various binary systems. In a polar alignment, a circumbinary disk is inclined by 90 degrees relative to the binary orbital plane. I find that terrestrial planet formation in a polar configuration may be as …

Quality Assurance Procedures Implementation For Varian Truebeam, Yongquan Jiang

UNLV Theses, Dissertations, Professional Papers, and Capstones

Department of radiation oncology of Oncology Nevada updated its linear accelerator (LINAC) from Varian Clinac iX to a newer model known as Varian TrueBeam. The Varian TrueBeam LINAC includes 6x, 6xFFF (i.e., 6x without flattening filter known as flattening filter free), 10x, 10xFFF, 15x photon beams and 6e, 9e, 12e MeV electron beams. This system is also equipped with a 6 degree of freedom (DOF) couch, RapidArc, kV on board imager, MV portal imager and Cone Beam CT (CBCT) imaging. This system allows the clinical delivery of modern image guided radiation therapy (IGRT) modalities such as IMRT/VMAT, and SRS/SRT/SBRT. The …

Prediction Of Pathogenic Mutations In Spermine/Spermidine Synthases, Shannon Bonomi

All Theses

As genetic technology and information become continuously more sophisticated and applied to the prevention and treatment of diseases, the need to understand the effects of genetic variants becomes an important task with regards to assessing disease risk. In the specific case of intellectual disabilities, prenatal screenings is an important diagnostic tool that prepares families and health professionals for the arrival of a child who may need immediate, specialized care. Cell Free DNA screenings are routine for determining sex and provide the opportunity to discover genetic anomalies. However, this has little value unless mutations can be recognized as pathogenic and are …

Construction And Testing Of Large-Area Gem Detectors For The Forward Muon Endcap Upgrade Of The Cms Experiment And Vector-Portal Search For Dark Matter Particles With Dimuon Pairs At √S = 13 Tev, Mehdi Rahmani

Theses and Dissertations

In this thesis, I present my contributions to the second major upgrade of the Compact Muon Solenoid at the Large Hadron Collider and the analysis that I performed on the data collected by the Compact Muon Solenoid during the 2018 and 2017 era. Alongside my team, I assembled and tested ten Gaseous Electron Multipliers to upgrade the forward region at the Compact Muon Solenoid, all of which are now installed at the dedicated stations. The campaign for producing these detectors succeeded in a twoyear-long prototyping endeavor, where I examined the procedural steps for production to optimize the production and testing …

Ab Initio Studies Of Structure And Properties Of Group-Iv Monochalcogenide Monolayers, Shiva Prasad Poudel

Graduate Theses and Dissertations

The goal of this dissertation is to study the structure of ferroelectric group-IV monochalcogenide monolayers (MMLs) and their material properties. This work also established a new buckled honeycomb phase of these monolayers. Chapter 1 serves as an introduction where the motivation for these studies is established. In chapter 2, I used eight different exchange-correlation functionals (XC) to study the structure of these 2D ferroelectrics and found that their properties are independent of the choice of XC functionals. These findings reveal that the ground-state ferroelectric unit cell can be described by only five independent parameters, whereas their paraelectric (square or rectangular) …

Dissociative Excitation, Ionization, And Fragmentation Processes For Nitrogen, Oxygen, Methane, And Water Molecules By Electron Bombardment, M. Gochitashvili, R. Lomsazde, D. Kuparashvili, O. Taboridze, Roman Ya. Kezerashvili

Publications and Research

Electron–impact ionization and fragmentation of molecules are investigated by the chromatography mass-spectrometry device. While the excitation processes are investigated by an optical spectroscopy method. The spectral analysis is performed in the vacuum ultraviolet 50-130 nm spectral regions. The absolute value of the fragmentation cross-section in the dissociative ionization and excitation processes is determined. Measurements are performed in the electron energy range 25-120eV for ionization and 200-500eV for excitation processes respectively.

Estimating The Analytical Performance Of Raman Spectroscopy For Quantification Of Active Ingredients In Human Stratum Corneum, Hichem Kichou, Emilie Munnier, Yuri Dancik, Kamilia Kemel, Hugh Byrne, Ali Tfayli, Dominique Bertrand, Martin Soucé, Igor Chourpa, Franck Bonnier

Articles

Confocal Raman microscopy (CRM) has become a versatile technique that can be applied routinely to monitor skin penetration of active molecules. In the present study, CRM coupled to multivariate analysis (namely PLSR—partial least squares regression) is used for the quantitative measurement of an active ingredient (AI) applied to isolated (ex vivo) human stratum corneum (SC), using systematically varied doses of resorcinol, as model compound, and the performance is quantified according to key figures of merit defined by regulatory bodies (ICH, FDA, and EMA). A methodology is thus demonstrated to establish the limit of detection (LOD), precision, accuracy, sensitivity (SEN), and …

Reconciling The Results Of The Z ∼2 Mosdef And Kbss-Mosfire Surveys, Jordan N. Runco, Naveen A. Reddy, Alice E. Shapley, Charles C. Steidel, Ryan L. Sanders, Allison L. Strom, Alison L. Coil, Mariska Kriek, Bahram Mobasher, Max Pettini, Gwen C. Rudie, Brian Siana, Michael W. Topping, Ryan F. Trainor, William R. Freeman, Irene Shivaei, Mojegan Azadi, Sedona H. Price, Gene C.K. Leung, Tara Fetherolf, Laura De Groot, Tom Zick, Guillermo Barro

Pacific Faculty Work

The combination of the MOSDEF and KBSS-MOSFIRE surveys represents the largest joint investment of Keck/MOSFIRE time to date, with ∼3000 galaxies at 1.4 z 3.8, roughly half of which are at z ∼2. MOSDEF is photometric- and spectroscopic-redshift selected with a rest-optical magnitude limit, while KBSS-MOSFIRE is primarily selected based on rest-UV colours and a rest-UV magnitude limit. Analysing both surveys in a uniform manner with consistent spectral-energy- distribution (SED) models, we find that the MOSDEF z ∼2 targeted sample has higher median M ∗and redder rest U −V colour than the KBSS-MOSFIRE z ∼2 targeted sample, and smaller median …

Experimental Demonstration Of Continuous Quantum Error Correction, William P. Livingston, Machiel S. Blok, Emmanuel Flurin, Justin Dressel, Andrew N. Jordan, Irfan Siddiqi

Mathematics, Physics, and Computer Science Faculty Articles and Research

The storage and processing of quantum information are susceptible to external noise, resulting in computational errors. A powerful method to suppress these effects is quantum error correction. Typically, quantum error correction is executed in discrete rounds, using entangling gates and projective measurement on ancillary qubits to complete each round of error correction. Here we use direct parity measurements to implement a continuous quantum bit-flip correction code in a resource-efficient manner, eliminating entangling gates, ancillary qubits, and their associated errors. An FPGA controller actively corrects errors as they are detected, achieving an average bit-flip detection efficiency of up to 91%. Furthermore, …

Dispersion In High Temperature Superconductors, Lazar Novakovic

Undergraduate Research Symposium Podium Presentations

Superconductors are used in many different industries: Efficient power transmission, Maglev train, MRIs

Controlling Unequal Surface Energy Results Caused By Test Liquids: The Case Of Uv/O3 Treated Pet, Bilge N. Altay, Paul D. Fleming, Md Arifur Rahman, Alexandra Pekarovicova, Bruce Myers, Cem Aydemir, Arif Karademir

Articles

Ultraviolet/ozone (UV/O3) treatment has been reported to be an effective method to modify properties such as wettability, adhesion or adsorption of plastic surfaces. The change in the surface is measured by contact angle analysis, which employs liquids and their surface tensions (ST) to estimate the surface energy (SE). We found two different practices in the scientific community: (1) the majority of researchers adopted the ST value of liquids from the literature, while (2) other researchers conducted real-time measurements in the lab under ambient conditions prior to SE estimation. To the best of our knowledge, there is no study that compares …

Using Supervised Learning Algorithms As A Follow-Up Method In The Search Of Gravitational Waves From Core-Collapse Supernovae, Javier M. Antelis, Marco Cavaglia, Travis Hansen, Mannuel D. Morales, Claudia Moreno, Soma Mukherjee, Marek J. Szczepańczyk, Michele Zanolin

Physics & Astronomy Faculty Publications

We present a follow-up method based on supervised machine learning (ML) to improve the performance in the search of gravitational wave (GW) bursts from core-collapse supernovae (CCSNe) using the coherent WaveBurst (cWB) pipeline. The ML model discriminates noise from signal events by using a set of reconstruction parameters provided by cWB as features. Detected noise events are discarded yielding a reduction in the false alarm rate (FAR) and the false alarm probability thus enhancing the statistical significance. We tested the proposed method using strain data from the first half of the third observing run of advanced LIGO, and CCSNe GW …

Search For Electroweak Production Of Charginos And Neutralinos In Proton-Proton Collisions At √S = 13 Tev, A. Tumasyan

Department of Physics and Astronomy: Faculty Publications

A direct search for electroweak production of charginos and neutralinos is presented. Events with three or four leptons, with up to two hadronically decaying τ leptons, or two same-sign light leptons are analyzed. The data sample consists of 137 fb⁻¹ of proton-proton collisions with a center of mass energy of 13TeV, recorded with the CMS detector at the LHC. The results are interpreted in terms of several simplified models. These represent a broad range of production and decay scenarios for charginos and neutralinos. A parametric neural network is used to target several of the models with large backgrounds. In …