Physics Commons^™

Machine Learning-Based Regression For Magnetic Field Prediction From Odmr Spectral Data, Jesse B. Hernandez

Electronic Theses, Projects, and Dissertations

Optically Detected Magnetic Resonance (ODMR) using nitrogen-vacancy (NV) centers in diamond enables sensitive, room-temperature magnetic field sensing, but real ODMR spectra are often noisy and difficult to analyze with traditional peak-fitting methods. This thesis investigates whether machine learning can reliably predict magnetic field strength directly from ODMR spectra, and compares four model families under a single regression task: a random forest, an artificial neural network (ANN), a one-dimensional convolutional neural network (1D-CNN), and a Transformer.

Training data were generated from an NV-ensemble simulation calibrated to real measurements provided by the Ulsan National Institute of Science and Technology (UNIST), spanning 0 …

Pentagonal Pdte2 Monolayer For Sustainable Solar-Driven Hydrogen Production, Narender Kumar, Shambhu Bhandari, Dario Alfè, Ravindra Pandey, Nacir Tit

Michigan Tech Publications

This investigation demonstrates that the pentagonal PdTe2 (penta-PdTe2) monolayer is a highly tunable two-dimensional (2D) photocatalyst, characterized by the bandgap of 1.87 eV and high hole mobility. Using density functional theory calculations with the HSE06 functional, we show that tensile strain engineering (particularly at +2% and +3%) is essential for enabling spontaneous water splitting. At these strain values, the valence-band maximum and conduction-band maximum straddle the water redox potentials (H+/H2 and O2/H2O) under both acidic (pH = 0) and neutral (pH = 7) conditions. The monolayer's low hole effective mass facilitates rapid charge extraction, mitigating recombination and driving the oxygen …

Are Lagrangians Involving Fractional Derivatives Physically Viable?, Nicola Fabiano

Turkish Journal of Physics

The recent trend of incorporating fractional derivatives into Lagrangians prompts a critical assessment of their physical viability. This work analyzes such theories through the lenses of classical mechanics and quantum field theory (QFT), revealing profound foundational issues. While the nonlocal nature of fractional operators circumvents Ostrogradsky's theorem, it introduces more severe problems. Classically, these include a complicated variational principle and the violation of energy conservation due to broken time-translation symmetry. In QFT, the pathologies are fatal: the propagator violates the K\"all\'en--Lehmann spectral representation, leading to acausal propagation, ghost states, complex poles, and a loss of unitarity. We conclude that Lagrangians …

Electron-Loss And Electron-Capture Cross Sections In  H + H₂⁺ Collisions, Saed J. Al Atawneh, Oqlah Al-Refai, Mohammed Abu-Seileek, Feras Afaneh

Turkish Journal of Physics

We investigate projectile electron-loss, target electron-loss, and target electron capture in H + H₂⁺ collisions using classical trajectory Monte Carlo (CTMC) and quantum-corrected classical trajectory Monte Carlo (QCTMC) methods within a fully four-body model. Energy-dependent cross sections are reported for all three channels. For projectile electron-loss, we additionally analyze impact-parameter-dependent probabilities and representative trajectories. The QCTMC method incorporates Heisenberg corrections, improving accuracy at low impact energies. Projectile and target electron-loss cross sections peak at intermediate energies and exhibit good agreement with H + H₂⁺ data at high energies. At low to intermediate energies, projectile electron-loss exceeds target electron-loss because the …

Nonlinear Mode Crossing And Spontaneous Frequency Comb Generation In Driven Magnetic Nanodisks, Hasan Pi̇şki̇n

Turkish Journal of Physics

Nonlinear magnetization dynamics in confined nanostructures provide a rich platform for fundamental studies and advanced spintronic applications. Here, we investigate the driven dynamics of a perpendicularly magnetized permalloy nanodisk using high-resolution micromagnetic simulations. In the linear regime, geometric confinement quantizes the uniform precession into discrete radial standing spin-wave (SSW) modes. As the excitation amplitude increases, the fundamental Kittel mode exhibits a pronounced nonlinear frequency shift relative to the higher-order SSW modes, ultimately leading to a critical mode crossing associated with nonlinear resonance overlap and the breakdown of modal orthogonality. Time-domain analysis reveals that strong mode hybridization governs the ensuing dynamics, …

Microscopic Study Of Β-Decay And Stellar Weak Rates In Neutron-Rich Scandium Isotopes, Wajeeha Khalid, Jameel-Un Nabi, Maria Ramzan

Turkish Journal of Physics

This study provides a critical investigation of the β-decay characteristics of neutron-rich scandium isotopes (53-65Sc) using the proton-neutron quasiparticle random phase approximation (pn-QRPA) model. The theoretical framework allows for a microscopic understanding of spin-isospin excitation modes that are essential for examining weak interaction phenomena. Charge-changing Gamow-Teller (GT) strength distributions were calculated and found to agree well with existing experimental results, thereby confirming the model's capacity to accurately represent the nuclear configuration of these isotopes. The computed β-decay half-lives and corresponding log ft values exhibit good agreement with experimental data, further validating the GT strength distributions and reinforcing the consistency of …

Comparison Of Umbral Dot Physical Properties In Developed And Undeveloped Sunspots, Muhammed Ali̇ Çalişir, Ali̇ Kilçik, Vasyl Yurchyshyn

Turkish Journal of Physics

Sunspots are cool regions where the magnetic field is significantly stronger than in the surrounding photosphere, and their darkest central regions are known as the umbra. Umbral dots (UDs) are small, bright features within the umbra that represent convective motions partially suppressed by strong magnetic fields. In this study, high-resolution images from the Goode Solar Telescope (GST) at Big Bear Solar Observatory (BBSO) were used to analyze four sunspots at different evolutionary stages, including two developed and two undeveloped sunspots. The physical properties of UDs, including brightness, diameter, eccentricity, lifetime, and dynamic velocity, were measured and compared across these sunspots …

Stress–Strain Behavior Of The High-Entropy Cantor Alloy Crmnfeconi Using A Deep Neural Network Potential, Nguyen Le Hoai Phuong, Le Huu Nghia, Huynh Khanh Van, Vo Khuong Dien, Nguyen Thanh Tien

Turkish Journal of Physics

Machine learning interatomic potentials (MLIPs) provide an efficient approach to large-scale molecular dynamics simulations of high-entropy alloys. In this work, an MLIP trained on AIMD data was developed for the CrMnFeCoNi Cantor alloy and validated against DFT calculations. In addition, we compared MLIP results with those obtained using the classical modified embedded atom method (MEAM)-based interatomic potential for the CrMnFeCoNi Cantor alloy. The model achieved energy and force RMSEs of 7.39 x 10-6 meV/atom and 4.46 x 10-3 eV/A, respectively. Tensile simulations demonstrated that the MLIP accurately reproduced the stress–strain response, elastic constants, and deformation mechanisms observed in DFT calculations. …

Spacer-Mediated Gold Nanocube Arrays For Edge-Localized Excitonic Enhancement In Monolayer Mos2​, Abdullah Efe Yildiz, Emre Ozan Polat

Turkish Journal of Physics

Plasmonic nanostructures offer an effective route for enhancing light-matter interaction in atomically thin semiconductors, whose optical response is intrinsically limited by their subnanometer active thickness. Here, we numerically investigate excitonic enhancement in monolayer (ML) Molybdenum Disulfide (MoS2) coupled to size-tuned gold (Au) nanocube arrays separated by thin aluminum oxide (Al2O3) and hexagonal boron nitride (h-BN) spacer layers. By varying the nanocube side length, the localized surface plasmon resonance is tuned across the visible spectral range to modulate the A- and B-excitonic transitions of monolayer MoS2.We show that the nanocube-size-dependent spectral redshift can be further controlled through the spacer material and …

Theoretical Construction Of Light Hexaquarks And Their Substantiation By Seven-Dimensional Representation Of Su(2) Group, Mayank Joshi, Shuchi Bisht, Navjot Hothi, Manish Bisht

Turkish Journal of Physics

This manuscript presents a theoretical approach to constructing light hexaquarks using up and down quarks. These light exotic hexaquarks are shown to exhibit a seven-dimensional representation of the SU(2) isospin group. Additionally, the isospin septuplet is developed along with the quintet, triplet, and singlet representations for these light exotic hexaquarks. These particles are essentially mesonic in nature and also satisfy the requirements of the Kronecker product. Furthermore, the physical characteristics and weights of the respective states are intrinsically provided for these light hexaquarks.

Investigation Of The Production Technology Of Environmentally Safe Urethane Oligomers Based On Local Raw Materials, Bakhtiyor Kudratovich Shaykulov, Dilafruza Ruziboevna Akbarova Gulboeva, Fayzulla Nurmuminovich Nurqulov

Technical science and innovation

This paper investigates the step-by-step poly condensation pathway for synthesizing environmentally friendly, non-isocyanate urethane oligomers derived from local and safe raw materials: urea and ethylene glycol. The influence of thermodynamic parameters on the target product yield was systematically evaluated to determine the optimum technological matrix. Specifically, a 1:2 reactant mass ratio, a stable stationary temperature of 150-155 °C, and a reaction duration of 2 hours under an inert nitrogen atmosphere resulted in a sustainable and reproducible yield of 72%. Thermal degradation and competitive side-product condensations were activated above 160 °C, leading to a sharp drop in overall chemical efficiency. The …

Radiological And Chemical Safety Assessment Of Drinking Water From Treatment Plants And Rivers In Kut City, Iraq, Ahmed A. Alswaty, Hadi D. Alattabi

Karbala International Journal of Modern Science

Climate change and increasing anthropogenic activities, particularly wastewater discharge into rivers, have raised pollution levels in the water sources of Kut City, necessitating an assessment of the radiological and chemical safety of drinking water at the city's treatment plants. Thirteen water samples were collected, comprising ten treated and three raw water samples from the source rivers. An HPGe detector was used to measure the radionuclides ²¹⁴Bi, ²¹⁴Pb, ²¹²Bi, ²¹²Pb, ⁴⁰K, and ¹³⁷Cs. All measured radionuclides were below the minimum detectable activity (MDA). ICP-OES analysis supported these findings, as U concentrations in most samples were …

Noise Characterization And Mitigation In Intermediate-Scale Quantum Systems, Muhammad Qasim Khan

Dartmouth College Ph.D Dissertations

Current quantum processors, at the intermediate scale of tens to hundreds of qubits, remain error-limited. This thesis studies two related sources of error. The first is environmental noise, which may have temporal and spatial correlations and nonclassical components. The second is state-preparation and measurement (SPAM) error, which arises in the operations used to characterize this noise, a prerequisite for boosting operational fidelities. Neither can be characterized alone. Noise spectroscopy techniques use imperfect preparation and readout, while SPAM characterization is affected by qubit decoherence. Our methods vary measurement depth, drive duration, or sequence repetition so each source changes the measured signal …

Quantum Mechanics, Non-Locality, And The Space Discreteness Hypothesis, Wilson A. Zuniga-Galindo

School of Mathematical & Statistical Sciences Faculty Publications

The space discreteness hypothesis asserts that the nature of space at short distances is radically different from that at large distances. Based on the Bronstein inequality, here, we use a totally disconnected topological space X as a model for the physical space at short distances. However, we consider the time as a real variable. In this framework, the Dirac–von Neumann formalism can be used. This discreteness hypothesis implies that given two different points in space, there is no continuous curve (a world line) joining them. Consequently, this hypothesis is not compatible with the theory of relativity. We propose R×(R×X)3 as …

Electrical Characterization Of Pvdf–Bzt-Bct Composite Materials For Energy Storage Applications, Aidana Ospanova '28, Pumpkin Nguyen, Kenneth L. Brown, Guangjun Qu

Annual Student Research Poster Session

This project focused on the synthesis of ceramics and polymer–ceramic composite materials for increasing energy storage density. Over ten weeks, BZT-BCT and CCTO ceramics were synthesized, and more than 50 ceramic and PVDF–ceramic composite samples were prepared with ceramic concentrations ranging from 0.5% to 30% by weight. Different synthesis and film-processing conditions were investigated, including ceramic-to-PVDF ratios, film sizes, temperatures, and hold times. Powder X-ray diffraction (XRD) was used to verify the synthesized ceramic phases. Later in the project, carbon nanotubes (CNTs) and PTFE were incorporated into selected composites, with different CNT concentrations investigated for their effects on energy storage …

Implementation Of The Problem-Based Learning Model On The Topic Of The Immune System To Enhance The Critical Thinking Skills Of Grade Xi B Students At Sman 1 Tojo, Nani Sofyanti, Sutrisnawati Sutrisnawati, Vita Indri Febriani, Mohammad Jamhari, Bustamin Bustamin, Raya Agni

Jurnal Pendidikan Sains

Critical-thinking skills are essential competencies for students in 21st-century learning. Preliminary classroom observations in Class XI B at SMAN 1 Tojo indicated that instruction remained predominantly teacher-centered and provided limited opportunities for students to engage in activities involving interpretation, analysis, evaluation, and inference. This study aimed to improve students’ critical-thinking skills through the implementation of Problem-Based Learning (PBL) on the immune system topic. The study employed a Classroom Action Research (CAR) design conducted over two cycles, involving 28 students in Class XI B. Data were collected using a teacher activity observation sheet and critical-thinking skills tests assessing four indicators: interpretation, …

Silicon Nitride Thin Film Deposited By Plasma-Enhanced Chemical Vapour Deposition Technique For Various Device Applications, Anayesu Bariki Malisa

Tanzania Journal of Science

This work reports on silicon nitride (SiNx) thin film deposited by the Plasma-Enhanced Chemical Vapour Deposition (PECVD) technique. The film was characterized by Variable Angle Spectroscopic Ellipsometry (VASE) to obtain optical constants 𝑛, 𝑘 and thickness using the Cauchy layer built on the Lorentz oscillator model and the B-spline model. The determined optical band gap 𝐸𝑜𝑝𝑡𝑖𝑐𝑎𝑙 for direct transition was 3.2 𝑒𝑉 and that for indirect transition was 2.13 𝑒𝑉. Film characterization was performed by Fourier Transform Infra-Red spectroscopy (FTIR) at two different angles of incidence of 15 degrees to probe deep layers and 65 degrees (Brewster’s angle) to excite …

Assessment Of Inter-Observer Variability In Delineating High-Risk Clinical Target Volumes And Organs At Risk In Cervical Cancer Brachytherapy, Atumaini A. Makoba, Julius S. Chiuyo, Innocent J. Lugendo

Tanzania Journal of Science

Achieving precise target volume delineation during cervical cancer treatment poses challenges due to several reasons, including difficulties in establishing the precise geometrical location of the gross target volume. Inter-observer variability in contouring anatomical structures poses a critical challenge to treatment consistency, delineation, and dosimetry accuracy. Volumetric and dosimetric records of 20 patients treated with gynecologic high-dose rate brachytherapy were analyzed to assess the interobserver variability between oncologists. Three radiation oncologists independently examined the organs at risk and high-risk critical organs on 20 computed tomography scans. The volumetric and dosimetric relationship between the contours delineated by radiation oncologists was described using …

Thermo-Entropic Analysis Of Unsteady Mhd Nanofluid Couette Flow: A Classical Spectral Approach With An Exploratory Quantum Linear-Solver Application, Serai Israel Mosala, Oluwole Daniel Makinde, Azwinndini Muronga

Mathematical Modelling and Numerical Simulation with Applications

This study presents a thermo-entropic analysis of unsteady MHD nanofluid Couette flow, combining a classical bivariate spectral quasilinearisation (BI-SQLM) and Crank--Nicolson solution with an exploratory application of quantum linear solvers. An incompressible, electrically conducting nanofluid flows between parallel plates under partial slip and convective heat exchange; the discretised linear systems are additionally solved via the Harrow--Hassidim--Lloyd (HHL) algorithm and the Variational Quantum Linear Solver (VQLS). Results are presented for Pure Water, Cu-Water, and Al₂O₃-Water across seven parameter variations. The Hartmann number dominates velocity suppression and entropy amplification, while velocity slip reduces upper-wall entropy generation more than …

Effects Of Co-Rotating Cylinders And Boundary Conditions On Heat And Mass Transfer In A Trapezoidal Enclosure, Olalekan Adebayo Olayemi, Olalekan Tajudeen Popoola, Leke Thaddeus Oladimeji, Isaac Kayode Adegun, Taofiq Omoniyi Amoloye, Oluwatayo Babatope Ojo, Benjamin Ohida Daniel, Michael Olabode Ibiwoye

Mathematical Modelling and Numerical Simulation with Applications

This study investigates the effects of rotational speed $(\Omega)$, Richardson number $\left(Ri\right)$, and Lewis number $\left(Le\right)$ on heat and mass transfer (HMT) around two co-rotating cylinders symmetrically situated in a trapezoidal enclosure. In the double-diffusive mechanism, the bottom wall of the trapezium is at a high temperature $\left(T_h\right)$ and concentration $\left(C_h\right)$, while the top wall is at a low temperature $\left(T_c\right)$ and concentration $\left(C_c\right)$. The side walls are perfectly insulated with zero mass flux, while the buoyancy ratio $\left(Br\right)$ is fixed at 1.0.  Two thermal-mass boundary scenarios are considered. Scenario 1: Cylinders are thermally insulated with zero mass flux, and …