Physical Sciences and Mathematics Commons^™

Electrochemically Desulfurized Molybdenum Disulfide (Mos2) And Reduced Graphene Oxide Aerogel Composites As Efficient Electrocatalysts For Hydrogen Evolution, Sanju Gupta, Taylor Robinson, N. Dimakis

Physics and Astronomy Faculty Publications and Presentations

Recent developments in graphene related materials including molybdenum disulfide (MoS₂) is gaining popularity as efficient and cost-effective nanoscale electrocatalyst essential for hydrogen production. These “clean” energy technologies require delicate control over geometric, morphological, chemical and electronic structure affecting physical and electrochemical catalytic properties. In this work, we prepared three-dimensional hierarchical mesoporous aerogels consisting of two-dimensional functionalized graphene and MoS₂ nanosheets of varying ratio of components under hydrothermal–solvothermal conditions (P <20 >bar, T <200 >°C). We systematically characterized these hybrid aerogels in terms of surface morphology, microstructure, understand heterointerfaces interaction through electron microscopy, X-ray diffraction, optical absorption and emission …

Model Comparison From Ligo–Virgo Data On Gw170817’S Binary Components And Consequences For The Merger Remnant, B. P. Abbott, R. Abbott, Teviet Creighton, Mario C. Diaz, Soma Mukherjee, Volker Quetschke, Malik Rakhmanov, K. E. Ramirez, Satzhan Sitmukhambetov, Robert Stone, D. Tuyenbayev, W. H. Wang, A. K. Zadrozny

Physics and Astronomy Faculty Publications and Presentations

GW170817 is the very first observation of gravitational waves originating from the coalescence of two compact objects in the mass range of neutron stars, accompanied by electromagnetic counterparts, and offers an opportunity to directly probe the internal structure of neutron stars. We perform Bayesian model selection on a wide range of theoretical predictions for the neutron star equation of state. For the binary neutron star hypothesis, we find that we cannot rule out the majority of theoretical models considered. In addition, the gravitational-wave data alone does not rule out the possibility that one or both objects were low-mass black holes. …

Characterizing The Quantum Phase Transition Using A Flat Band In Circuit Qed Lattices, Gui-Lei Zhu, Xin-You Lü, Hamidreza Ramezani

Physics and Astronomy Faculty Publications and Presentations

We show the superradiant phase transition (SPT) can control the existence of flat band in an extended Dicke-Hubbard lattice [1]

A Guide To Ligo–Virgo Detector Noise And Extraction Of Transient Gravitational-Wave Signals, B. P. Abbott, R. Abbott, Teviet Creighton, Mario C. Diaz, Soma Mukherjee, Volker Quetschke, Malik Rakhmanov, K. E. Ramirez, Satzhan Sitmukhambetov, Robert Stone, D. Tuyenbayev, W. H. Wang, A. K. Zadrozny

Physics and Astronomy Faculty Publications and Presentations

The LIGO Scientific Collaboration and the Virgo Collaboration have cataloged eleven confidently detected gravitational-wave events during the first two observing runs of the advanced detector era. All eleven events were consistent with being from well-modeled mergers between compact stellar-mass objects: black holes or neutron stars. The data around the time of each of these events have been made publicly available through the gravitational-wave open science center. The entirety of the gravitational-wave strain data from the first and second observing runs have also now been made publicly available. There is considerable interest among the broad scientific community in understanding the data …

Characterization Of Neutron Irradiated Accident Tolerant Nuclear Fuel Cladding Silicon Carbide & Radiation Detector Deadtime, Bader Almutairi

Doctoral Dissertations

“In part I, the pulse shape characteristics generated by a Geiger Muller (GM) detector and recorded by an oscilloscope manually, were investigated. The objective of part I was (1) to find a correlation between pulse shape and the operating voltage; and (2) to assess if pulse shape properties followed distinct patterns comparable to detector deadtime findings reported by a previous study. It was observed that (1) there is a strong correlation between pulse shape and operating voltage, and (2) pulse shape falls in three distinct regions similar to detector deadtime. Furthermore, parts II and III are companions and share the …

Symmetry-Breaking In The Multi-Photon Ionization Dynamics Of Oriented Atoms, Aruma Handi Nishshanka Chandrajith De Silva

Doctoral Dissertations

“Laser cooling and trapping, femtosecond light creation, and coincident electron and ion momentum imaging was combined in a world-wide unique experimental setup. These state-of-the-art techniques were used to control atomic systems and analyze the few-body quantum dynamics in multi-photon ionization of lithium. An all-optical, near-resonant laser atom trap (AOT) was developed to prepare a lithium gas at milli-Kelvin temperatures. The atoms can be resonantly excited to the state 2² P_3/2(ml = +1) with a high degree of polarization and are used as a target to study atomic multi-photon ionization in the field of an intense laser source …

Long-Range Electroweak Amplitudes Of Single Hadrons From Euclidean Finite-Volume Correlation Functions, Raúl A. Briceño, Zohreh Davoudi, Maxwell T. Hansen, Matthias R. Schindler, Alessandro Baroni

Physics Faculty Publications

A relation is presented between single-hadron long-range matrix elements defined in a finite Euclidean spacetime and the corresponding infinite-volume Minkowski amplitudes. This relation is valid in the kinematic region where any number of two-hadron states can simultaneously go on shell, so that the effects of strongly coupled intermediate channels are included. These channels can consist of nonidentical particles with arbitrary intrinsic spins. The result accommodates general Lorentz structures as well as nonzero momentum transfer for the two external currents inserted between the single-hadron states. The formalism, therefore, generalizes the work by Christ et al. [Phys. Rev. D 91, 114510 …

Probing Few-Body Nuclear Dynamics Via ³H And ³He (E E'P) Pn Cross-Section Measurements, R. Cruz-Torres, F. Hauenstein, D. Bulumulla, C. Hyde, M. Khachatryan, M.N.H. Rashad, L.B. Weinstein, Et. Al., Jefferson Lab Hall A. Tritium Collaboration

Physics Faculty Publications

We report the first measurement of the (e, e'p) three-body breakup reaction cross sections in helium-3 (³He) and tritium (³H) at large momentum transfer [< Q²> ≈ 1.9 (GeV/c)²] and x_B> 1 kinematics, where the cross section should be sensitive to quasielastic (QE) scattering from single nucleons. The data cover missing momenta 40 ≤ p_miss ≤ 500 MeV/c that, in the QE limit with no rescattering, equals the initial momentum of the probed nucleon. The measured cross sections are compared with state-of-the-art ab initio calculations. Overall …

Quantitative Analysis Of Ekg And Blood Pressure Waveforms, Denise Erin Mckaig

Dissertations, Theses, and Masters Projects

In the intensive care unit (ICU) of a hospital, patients are monitored continuously and the data on those patients provide powerful diagnostic tools for the medical community. However, the patient data creates incredibly large data sets with instruments measuring multiple signals simultaneously. This work seeks to improve monitoring techniques through analysis of large data sets from former ICU patients. By knowing the outcomes of patients in the past, can we detect patterns to diagnose future patients while also reducing the amount of recorded information? This thesis first seeks to improve methods of storing infant electrocardiograms (EKGs) by reducing the full …

Application Of Optical Trapping To Obtain Single-Source Str Profiles From Forensically Relevant Body Fluid Mixtures With Modified Dna Analysis Workflow, Benjamin J. O'Brien

Master of Science in Forensic Science Directed Research Projects

Current methods of mixture separation in forensic DNA laboratories typically deconvolute the mixture after analysis using statistical analysis or probabilistic genotyping. To save time and effort of labs already backlogged, a method to separate mixtures on a cellular level before analysis needs to be developed. Optical trapping is a method that uses a focused 1064 nm laser to manipulate cells. Previous research has shown that approximately 50 spermatozoa or 15 leukocytes from a liquid sample are required to produce a full STR DNA profile. It was found that the number of spermatozoa required remains constant when the method of sample …

Collision Of Li2+ With Li(2s) And Li(2p): Differential And Total Ionization; Discrete Excitations; Elastic Scattering, And Total Cross Section, H.R.J. Walters, Colm T. Whelan

Physics Faculty Publications

The coupled pseudostate approximation (McGovern et al 2009 Phys. Rev. A 79 042707) has been applied to Li²⁺ + Li(2s, 2p_0,±₁) collisions at 16 MeV with emphasis on studying the fully differential ionization measurements of Ghanbari-Adivi et al in the azimuthal plane (2017 J. Phys. B: At. Mol. Opt. Phys. 50 215202). The states of the valence electron in the Li target are calculated using the model potential of Stein (1993 J. Phys. B: At. Mol. Opt. Phys. 26 2087). Altogether 164 states with angular momenta l = 0 to 9 are employed in …

Measurement Of The ³He Spin-Structure Functions And Of Neutron (³He) Spin-Dependent Sum Rules At 0 .035≤Q²≤0 .24 Gev², V. Sulkosky, D. Hayes, C. E. Hyde, P. E. Ulmer, X. Zheng, L. Zhu, Et Al., Jefferson Lab E97-110 Collaboration

Physics Faculty Publications

The spin-structure functions g₁ and g₂, and the spin-dependent partial cross-section σπ have been extracted from the polarized cross-sections differences,

Δσ∥ (ν, Q²) and Δσ⊥ (ν,Q²) measured for the 3^→He(^→e, e')X reaction, in the E97-110 experiment at Jefferson Lab. Polarized electrons with energies from 1.147 to 4.404GeV were scattered at angles of 6^◦and 9^◦ from a longitudinally or transversely polarized ³He target. The data cover the kinematic regions of the quasi-elastic, …

Dynamic Pair-Breaking Current, Critical Superfluid Velocity, And Nonlinear Electromagnetic Response Of Nonequilibrium Superconductors, Ahmad Sheikhzada, Alex Gurevich

Physics Faculty Publications

We report numerical calculations of a dynamic pair-breaking current density J_d and a critical superfluid velocity v_d in a nonequilibrium superconductor carrying a uniform, large-amplitude AC current density J(t)=J_asinΩt with Ω well below the gap frequency Ω ≪ Δ₀/h. The dependencies J_d(Ω,T) and v_d(Ω,T) near the critical temperature T_cwere calculated from either the full time-dependent nonequilibrium equations for a dirty s-wave superconductor or the time-dependent Ginzburg-Landau (TDGL) equations for a gapped superconductor, taking into account the GL relaxation time of the order parameter GL …

Measurement Of The Single-Spin Asymmetry A⁰ʸ In Quasi-Elastic ³He↑(E,E'N) Scattering At 0.4 < Q2 < 1.0 Gev/C2, E. Long, Y.W. Zhang, M. Mihovilovic, M. Canan, S. Golge, L. Zhu

Physics Faculty Publications

Due to the lack of free neutron targets, studies of the structure of the neutron are typically made by scattering electrons from either ²H or ³He targets. In order to extract useful neutron information from a ³He target, one must understand how the neutron in a ³He system differs from a free neutron by taking into account nuclear effects such as final state interactions and meson exchange currents. The target single spin asymmetry A⁰ʸ is an ideal probe of such effects, as any deviation from zero indicates effects beyond plane wave impulse approximation. New measurements of the target single spin …

Plasmonic Slab Waveguides: Theory & Application For Sensors, Anum Khattak

Theses and Dissertations (Comprehensive)

Through surface plasmon polaritons (SPPs) that propagate along the interface between a metal and a dielectric material, plasmonic waveguides have the ability to confine light at subwavelength scale beyond the diffraction limit, which opens a promising platform to further downsize the active and passive photonic devices. The fields of the SPPs have maximum amplitude at the metal/dielectric interface and decay exponentially toward both media, where the penetration of the fields in the dielectric is very susceptible to the change in the refractive index of the dielectric. This makes surface plasmon resonance (SPR) a remarkable technique in sensor applications to investigate …

Ensemble Lung Segmentation System Using Deep Neural Networks, Redha A. Ali, Russell C. Hardie, Hussin K. Ragb

Electrical and Computer Engineering Faculty Publications

Lung segmentation is a significant step in developing computer-aided diagnosis (CAD) using Chest Radiographs (CRs). CRs are used for diagnosis of the 2019 novel coronavirus disease (COVID-19), lung cancer, tuberculosis, and pneumonia. Hence, developing a Computer-Aided Detection (CAD) system would provide a second opinion to help radiologists in the reading process, increase objectivity, and reduce the workload. In this paper, we present the implementation of our ensemble deep learning model for lung segmentation. This model is based on the original DeepLabV3+, which is the extended model of DeepLabV3. Our model utilizes various architectures as a backbone of DeepLabV3+, such as …

Characterization Of Retinol Stabilized In Phosphatidylcholine Vesicles With And Without Antioxidants, Yekaterina G. Chmykh, Jay Nadeau

Physics Faculty Publications and Presentations

Retinol stability has been reported to be improved by encapsulation in liposomes, both with and without cholesterol. However, this improvement is limited because of lipid peroxidation. In this study, we compare the stability of retinol in phosphatidylcholine liposomes under ultraviolet (UV) light or standard room air, with and without the addition of antioxidants. Both butylated hydroxytoluene (BHT) and a proprietary mix (StoppOx) improved the shelf stability from vesicles, including within the aqueous layer. Fluorescence lifetimes were equally heterogeneous. Under UV irradiation, StoppOx protected retinol for significantly longer than BHT and via different mechanisms. This suggests that natural antioxidants work well …

Membraneless H2o2 Fuel Cells Driven By Metallophthalocyanine Electrocatalysts, Bao Nguyen, Neal Kuperman, Gary Goncher, Raj Solanski

Physics Faculty Publications and Presentations

One-compartment hydrogen peroxide fuel cells with Co, Cu, and Fe phthalocyanine (PC) and iron nitride (FexN) as cathodes and Ni anode have been investigated as sustainable energy sources. The cells were operated under acidic conditions and at room temperature. The potentials for onset of the catalytic currents in these cells were determined via cyclic voltammograms. The reduction current onset potentials of FePC, CoPC, CuPC and FexN were 0.56 V, 0.42 V, 0.51 V and 0.57 V, respectively. Potentialcurrent linear sweep voltammetry was utilized to determine the open circuit potentials (OCP) and the power densities the fuel cells. The OCPs for …

Enhancing Final Image Contrast In Off-Axis Digital Holography Using Residual Fringes, Manuel Bedrossian, Kent Wallace, Eugene Serabyn, Chris Lindensmith, Jay Nadeau

Physics Faculty Publications and Presentations

We show that background fringe-pattern subtraction is a useful technique for removing static noise from off-axis holographic reconstructions and can enhance image contrast in volumetric reconstructions by an order of magnitude in the case for instruments with relatively stable fringes. We demonstrate the fundamental principle of this technique and introduce some practical considerations that must be made when implementing this scheme, such as quantifying fringe stability. This work also shows an experimental verification of the background fringe subtraction scheme using various biological samples.

Gold/Qds-Embedded-Ceria Nanoparticles: Optical Fluorescence Enhancement As A Quenching Sensor, Nader Shehata, Effat Samir, Ishac Kandas

Electrical & Computer Engineering Faculty Publications

This work focuses on improving the fluorescence intensity of cerium oxide (ceria) nanoparticles (NPs) through added plasmonic nanostructures. Ceria nanoparticles are fluorescent nanostructures which can emit visible fluorescence emissions under violet excitation. Here, we investigated different added plasmonic nanostructures, such as gold nanoparticles (Au NPs) and Cadmium sulfide/selenide quantum dots (CdS/CdSe QDs), to check the enhancement of fluorescence intensity emissions caused by ceria NPs. Different plasmonic resonances of both aforementioned nanostructures have been selected to develop optical coupling with both fluorescence excitation and emission wavelengths of ceria. In addition, different additions whether in-situ or post-synthesis have been investigated. We found …

Analysis Of Chaotic And Regular Behavior Of Matinyan-Yang-Mills-Higgshamiltonian System, Engi̇n Kandiran, Avadi̇s Si̇mon Hacinliyan

Turkish Journal of Physics

In this study we analyze the Matinyan-Yang-Mills-Higgs (MYMH) system, based on semiclassical solutions to a Yang-Mills model, using Poincaré surfaces of section and the method of averaging. To investigate the possible chaotic behavior for the system, we simulate the trajectories of the system and calculate the Lyapunov exponents. We observe that the system displays weakly chaotic behavior. We search for the existence of approximately conserved quantities for the system using the method of averaging. In this way, we show the existence of four fixed points where period orbits exist.

Reactive Wetting Of Metallic/Ceramic (Al/Α-Al2 O3 ) Systems: A Parallel Moleculardynamics Simulation Study, Gürcan Aral

Turkish Journal of Physics

The reactive wetting process of a flat solid alumina (α-Al2 O3) ceramic surface by metallic aluminum (Al) nanodroplets with different shapes (spherical, cylindrical, and layer) is studied using parallel molecular dynamics (MD) simulations based on a variable charge MD method, with focuses on heat transfer, mass transfer, and the structure of the reactive region at the Al/α-Al2 O3 interface. We find that the diffusion of oxygen (O) atoms from the substrate into the droplet leads to the formation of a continuous layer of reaction product at the interface. The diffusion length of oxygen atoms into the spherical Al droplet is …

Atomic Layer Deposition Of Zirconium Oxide Thin Film On An Optical Fiber Forcladding Light Strippers, Ali̇ Karatutlu

Turkish Journal of Physics

Cladding light strippers are essential components in high-power fiber lasers used for removal of unwanted cladding light that can distort the beam quality or even damage the whole fiber laser system. In this study, an Atomic Layer Deposition system was used for the first time to prepare the cladding light stripper devices using a 40 nm thick zirconia layer grown on optical fiber. The thickness of the zirconia coating was confirmed using the Scanning Electron Microscopy (SEM) and the Ellipsometry techniques. The elemental analysis was also performed using the wavelength dispersive X-ray spectroscopy technique. The Raman spectroscopy and XRD data …

Structural And Optical Properties Of Zno Films Obtained On Mesoporous Sisubstrates By The Method Of Hf Magnetron Sputtering, Valeriy Kidalov, Alena Dyadenchuk, Yuriy Bacherikov, Anton Zhuk, Tetyana Gorbaniuk, Igor Rogozin, Vitali Kidalov

Turkish Journal of Physics

In the present work, ZnO films were obtained on mesoporous silicon substrates by the method of HF magnetron sputtering of a metallic zinc target in reaction oxygen and argon gas medium. The properties of the ZnO films obtained on mesoporous substrates were studied depending on the ratio of the partial pressures of the working gases (argon/oxygen). X-ray analysis showed that in the process of deposition, the ZnO films of a hexagonal structure were formed. The effect of the porous layer on the structural and luminescent properties of the thin ZnO films was studied. The results showed that the porous silicon …

Size-Dependent Electron Chemical Potential In Nanostructures Derived Fromstatistical Configuration, Desyana Olenka Margaretta, Nadya Amalia, Fisca Dian Utami, Riri Murniati, Sparisoma Viridi, Mikrajuddin Abdullah

Turkish Journal of Physics

We rederived the fermion distribution function by considering the effect of assembly size. We did not use Stirling approximation to avoid the deviation generated by this approximation for a small number of constituents and small assembly size. Furthermore, we identified that in small systems, the chemical potential should also depend on the assembly size. We also rederived a general expression for the size-dependent chemical potential from a statistical configuration and showed that it is consistent with the results from previously reported theoretical or simulation methods. Finally, we applied the model to derive a size-dependent thermoelectric power factor of nanostructured materials. …

Prediction Of Standard Enthalpies Of Formation Of Boron Nitride Nanocones, Fahimeh Shojaie

Turkish Journal of Physics

Prediction of the standard enthalpy of formation (ΔfH0298) of boron nitride nanocone (BNNCs) structures with disclination angles 60°, 120°, and 180°is recommended to be performed by the isodesmic reaction approach. NH3, BH3, and N2H4 were selected as key reference compounds. In order to calculate ΔfH0298 of nanocones, we must first calculate the enthalpies of nanocone rings at their apexes. For this purpose, ΔfH0298 values of 40 different structures, such as boron, nitrogen, and hydrogen compounds, have been calculated by combining Gaussian-4 (G4) theory calculations with the isodesmic and other balanced reactions approach. At each stage of the calculations, the previously …

Electrophysical Properties Of Pb 1-Xmnx Se Epitaxial Films Irradiatedby Γ-Quanta, Rahim Madatov, Rakshana Mamishova, Muslim Mamedov, Javanshir Ismayilov, Ulviya Faradjova

Turkish Journal of Physics

Herein, the effect of γ-quanta on electrophysical and photoelectric properties of p-type Pb1-xMnx Se epitaxial films obtained from the molecular cluster on the glass substrate by the method of condensation has been investigated. It has been established that the acceptor-type local levels with the ionization energy of 0.14 eV and 0.175 eV are generated, when p-type Pb1-xMnx Se (x = 0.01) epitaxial films are irradiated by γ-quanta at D >10 kGy doses. The increase in the photoconductivity in the low temperature range 80-180K is due to the discharge of 0.14eV level, but the decrease in the rate of change of …

Study Of Kno Scaling In The Emulsion Based Neutrino Experiments, Çağin Kamişcioğlu

Turkish Journal of Physics

KNO scaling was put forward by Koba-Nielsen-Olesen in 1972 and then tested by various experiments up to now. In this paper, the data on charged hadron multiplicity moments with KNO scaling of CHORUS and OPERA, both of them emulsion-based neutrino experiments, are compared. The results are given in detail which is very useful for tuning in MC event generators.

Investigation Of Some Nuclear Structure Properties Of 213bi, 201ti, 188re, 186re, 133xe, 131i, 125i, 123i, 111in, 94tc, 90y, 67ga, 67cu, 62cu, 61cu, 55co, And 48v Nuclei Used In Spect In Axial Deformation, Ozan Artun

Turkish Journal of Physics

The present work mainly purposed to investigate significant nuclear structure properties nuclei used in single photon emission computed tomography (SPECT), in addition to ground state nuclear properties such as the binding energy per particle, the root mean square (rms) charge, and proton and neutron radii. Besides, we calculated the neutron skin thicknesses (NST), the proton, neutron quadrupole moments ($Q_{P}, Q_{N})$, quadrupole deformation parameter ($\beta_{2})$, and the proton and neutron pairing energies ($P_{P}, P_{N})$ to determine shapes and deformations of SPECT nuclei including odd-odd or odd-even/even-odd nuclei in axial symmetry for Skyrme and Gogny interactions. To analyze the accuracy of the …

A Nonminimally Coupled, Conformally Extended Einstein-Maxwell Theory Of Pp-Waves, Dündar Teki̇n Dereli̇, Yorgo Şeni̇koğlu

Turkish Journal of Physics

A nonminimal coupling of Weyl curvatures to electromagnetic fields is considered in Brans-Dicke-Maxwell theory. The gravitational field equations are formulated in a Riemannian spacetime where the spacetime torsion is constrained to zero by the method of Lagrange multipliers in the language of exterior differential forms. The significance and ramifications of nonminimal couplings to gravity are examined in a pp-wave spacetime.