Physics Commons^™

Model Checks For Two-Sample Location-Scale, Atefeh Javidialsaadi

Dissertations

Two-sample location-scale refers to a model that permits a pair of standardized random variables to have a common distribution. This means that if X₁ and X₂ are two random variables with means µ₁ and µ₂ and standard deviations ?₁ and ?₂, then (X₁ - µ₁)/?₁ and (X₂ - µ₂)/?₂ have some common unspecified standard or base distribution F₀. Function-based hypothesis testing for these models refers to formal tests that would help determine whether or not two samples may have come from some location-scale …

Coherent Control Of Dispersive Waves, Jimmie Adriazola

Dissertations

This dissertation addresses some of the various issues which can arise when posing and solving optimization problems constrained by dispersive physics. Considered here are four technologically relevant experiments, each having their own unique challenges and physical settings including ultra-cold quantum fluids trapped by an external field, paraxial light propagation through a gradient index of refraction, light propagation in periodic photonic crystals, and surface gravity water waves over shallow and variable seabeds. In each of these settings, the physics can be modeled by dispersive wave equations, and the technological objective is to design the external trapping fields or propagation media such …

Experimental And Computational Studies Of Functionalized Carbon Nanotubes For Use In Energy Storage Devices And Membranes, Emine S. Karaman

Dissertations

Electrolytes with good interfacial stability are a crucial component of any electrochemical device. The development of novel gel polymer electrolytes (GEs) with good interface stability and better manufacturability is important for the development of the next generation electrochemical devices. Gel electrolytes are hybrid electrolyte materials, combining benefits of both liquid and solid systems. Compared with liquid and solid electrolytes, GEs open new design opportunities and do not require rigorous encapsulation methods. In this dissertation, studies on functionalized carbon nanotubes (fCNTs) and graphene oxide (GO) doped polyvinyl alcohol (PVA) based gel electrolytes (GEs) are reported. The ionic conductivity and mechanical strength …

Hydrodynamic Characterization Of Laboratory And Production Equipment For Pharmaceutical Testing And Manufacturing Using Experimental And Computational Approaches, Chadakarn Sirasitthichoke

Dissertations

The hydrodynamics of process units used in pharmaceutical industry, i.e., the distribution of velocity profiles and shear stresses within the vessel, often controls the process performance, significantly affecting product quality. The hydrodynamics is strongly influenced by several factors such as the vessel shape, stirrer type, presence of internals and baffles, agitation intensity, and liquid properties. Most of these parameters can be varied by the process designers and the operators to achieve the desired process outcomes. The impact of the hydrodynamics on the process outcome can be profound in both large vessels (e.g., reactors) and smaller vessels (e.g., dissolution vessels), involving …

Dependent Censoring In Survival Analysis, Zhongcheng Lin

Dissertations

This dissertation mainly consists of two parts. In the first part, some properties of bivariate Archimedean Copulas formed by two time-to-event random variables are discussed under the setting of left censoring, where these two variables are subject to one left-censored independent variable respectively. Some distributional results for their joint cdf under different censoring patterns are presented. Those results are expected to be useful in both model fitting and checking procedures for Archimedean copula models with bivariate left-censored data. As an application of the theoretical results that are obtained, a moment estimator of the dependence parameter in Archimedean copula models is …

Electric-Field-Driven Processes In Multiphase Fluid Systems, Qian Lei

Dissertations

Advantages of using electric fields in miniaturized apparatuses for a wide range of applications are revealed by numerous experimental and theoretical studies over the last several decades as it offers a simple and efficient method for manipulation of multiphase fluid systems. This approach is considered to be especially beneficial for control of boiling processes and colloidal suspensions considered in the presented work.

Boiling. Today's trends for enhancing boiling heat transfer in terrestrial and space applications focus on removal of bubbles to prevent formation of a vapor layer over the surface at a high overheat. In contrast, this dissertation presents a …

A Numerical Solution Of Water Flow In Unsaturated Soil With Evapotraspiration, Andrei Ludu, Harihar Khanal, Ramesh Chandra Timsina, Kedar Nath Uprety

Publications

Flow movement in unsaturated soil can be expressed by Richards equation. This equation can be obtained by applying the mass conversation law and the Darcy law. In this work, we solve one-dimensional Kirchhoff transformed Richards equation with loss of water due to the evaporation of unsaturated porous media (soils) and transpiration of plants numerically using Crank-Nicolson method. The result has compared with evapotranspiration function and without it in the governing equation. It has found that an additional work in time and flow movement is needs to reach the given boundary condition for the model without evapotranspiration.

Adaptive Sliding Mode Contouring Control Design Based On Reference Adjustment And Uncertainty Compensation For Feed Drive Systems, Mathew Renny Msukwa, Santos Kihwele

Tanzania Journal of Science

Industrial feed drive systems, particularly, ball-screw and lead-screw feed drives are among the dominating motion components in production and manufacturing industries. They operate around the clock at high speeds for coping with the rising production demands. Adversely, high-speed motions cause mechanical vibrations, high-energy consumption, and insufficient accuracy. Although there are many control strategies in the literature, such as sliding mode and model predictive controls, further research is necessary for precision enhancement and energy saving. This study focused on design of an adaptive sliding mode contouring control based on reference adjustment and uncertainty compensation for feed drive systems. A combined reference …

Rural Electrification Using Iliceto Shield Wire Scheme In Developing Countries: Tanzania Case Study, Heavenlight M Munisi, Santos Kihwele

Tanzania Journal of Science

Rural electrification rate in Tanzania is still very low despite the efforts made by the Rural Energy Agency (REA) in Tanzania. Rural electrification using medium voltage (MV) method has two major obstacles. First obstacle is high cost associated with the cost of extending the grid electricity to rural areas. Second obstacle is remoteness of the villages, which leads to high power loss during transmission. In lieu of economic extension of rural electrification areas, this paper proposes a low cost solution of Iliceto Shield Wire Scheme (ISWS). This technique involves insulating shield wires (SW) from high voltage (132-400 kV) transmission line …

Smart Electric Meter Deployment In Tanzania: A Survey, Theresia B Maziku, Kwame S Ibwe, Abdi Abdalla, Ellen A Kalinga

Tanzania Journal of Science

Using information and communication technologies (ICT) to make the electrical power network intelligent and smarter (smart grid) has been the focal point in transforming electrical power industry. The idea behind smart grid is to transform the Tanzanian power sector into a secure, adaptive, sustainable, and digitally enabled ecosystem that provides reliable and quality energy for all with active participation of stakeholders. Smart metering is a central segment in realizing smart grid. However, a big question is whether Tanzanian power stakeholders are ready for smart metering technology investments for household applications. Operation and maintenance of a smart metering solution is a …

Physical And Magnetic Properties Of Nanosized Mn0.5ni0.5¬Fe2-Xprxo4 Prepared By Co-Precipitation Method, Douaa El-Said Bakeer, Khulud Habanjar, Ghassan Youness, Mohammad Abou Ghoush

BAU Journal - Science and Technology

Nanosized Mn_0.5Ni_0.5Fe_2-xPr_xO₄, x=0.0, 0.02, 0.04, 0.06, 0.08, 0.1 and 0.15 are prepared by co-precipitation method at calcination temperature 650^oC for 4 hours. X-ray diffraction patterns show the presence of the cubic (Mn-Ni)- ferrite phase and anti-ferromagnetic a-Fe₂O₃. The variation in the lattice parameter “a” is due to the replacement of smaller radius ions Fe⁺³ by larger radius ions Pr⁺³. Transmission electron micrographs indicate that the particles are spherical in shape. The moderately agglomerated particles are present due to the …

Self-Assembly Of Black Cumin Oil-Based Nanoemulsion On Various Surfactants: A Molecular Dynamics Study, Aulia Fikri Hidayat, Taufik Muhammad Fakih

Makara Journal of Science

Black cumin is commonly used as traditional medicine due to its wide range of pharmacological potential. Black cumin oil (BCO) was often prepared as nanoemulsion to improve its solubility, stability, and bioavailability. This study was conducted to investigate the molecular behavior as well as structural evolution of BCO-surfactant systems during self-assembly micellization using molecular dynamics (MD) simulations. Several BCO constituents and variations of surfactants were employed to model BCO-surfactant systems. 50 ns of MD simulations were performed to elucidate their evolution of structures and physicochemical properties during formation. Results showed that BCO-tween20 and BCO-lecithin were able to form spherical-shaped micelles …

Scale Model Equations And Optimization For Annular Flow Of Non-Newtonian Fluids Between Eccentric And Rotating Cylinders, Wei Zhang, Pooya Khodaparast, Amin Mehrabian Dr., Amir Shojaei

Progress in Scale Modeling, an International Journal

A broad range of engineering applications involves helical flow of non-Newtonian fluids between two eccentric cylinders. These applications often require estimation of the frictional pressure losses along the axes of the cylinders. Laboratory flow loops are commonly used to study the flow characteristics at smaller scales of investigation. This study uses the laws of similarity and dimensional analysis to obtain a set of scaling equations between the laboratory and prototype scales of the described annular flow. These equations are derived for four types of fluid rheology including Newtonian, power-law, Bingham-plastic, and yield power-law.

Results are expressed through a set of …

A Nanoscale Shape-Discovery Framework Supporting Systematic Investigations Of Shape-Dependent Biological Effects And Immunomodulation, Wei Zhang, Hender Lopez, Luca Boselli, Paolo Bigini, André Perez-Potti, Zengchun Xie, Valentina Castagnola, Qi Cai, Camila P. Silveira, Joao M. De Araujo, Laura Talamini, Nicolò Panini, Giuseppe Ristagno, Martina B. Violatto, Stéphanie Devineau, Marco P. Monopoli, Mario Salmona, Valeria A. Giannone, Sandra Lara, Kenneth A. Dawson, Yan Yan

Articles

Since it is now possible to make, in a controlled fashion, an almost unlimited variety of nanostructure shapes, it is of increasing interest to understand the forms of biological control that nanoscale shape allows. However, a priori rational investigation of such a vast universe of shapes appears to present intractable fundamental and practical challenges. This has limited the useful systematic investigation of their biological interactions and the development of innovative nanoscale shape-dependent therapies. Here, we introduce a concept of biologically relevant inductive nanoscale shape discovery and evaluation that is ideally suited to, and will ultimately become, a vehicle for machine …

Splashing Of Large Helium Nanodroplets Upon Surface Collisions, Paul Martini, Simon Albertini, Felix Laimer, Miriam Meyer, Michael Gatchell, Olof E. Echt, Fabio Zappa, Paul Scheier

Faculty Publications

In the present work we observe that helium nanodroplets colliding with surfaces can exhibit splashing in a way that is analogous to classical liquids. We use transmission electron microscopy and mass spectrometry to demonstrate that neutral and ionic dopants embedded in the droplets are efficiently backscattered in such events. High abundances of weakly bound He-tagged ions of both polarities indicate a gentle extraction mechanism of these ions from the droplets upon collision with a solid surface. This backscattering process is observed for dopant particles with masses up to 400 kilodaltons, indicating an unexpected mechanism that effectively lowers deposition rates of …

All-Sky Search For Short Gravitational-Wave Bursts In The Third Advanced Ligo And Advanced Virgo Run, R. Abbott, T. Abbott, F. Acernese, K. Ackley, Teviet Creighton, Mario C. Diaz, Francisco Llamas, Soma Mukherjee, Volker Quetschke, Wenhui Wang

Physics & Astronomy Faculty Publications

This paper presents the results of a search for generic short-duration gravitational-wave transients in data from the third observing run of Advanced LIGO and Advanced Virgo. Transients with durations of milliseconds to a few seconds in the 24–4096 Hz frequency band are targeted by the search, with no assumptions made regarding the incoming signal direction, polarization, or morphology. Gravitational waves from compact binary coalescences that have been identified by other targeted analyses are detected, but no statistically significant evidence for other gravitational wave bursts is found. Sensitivities to a variety of signals are presented. These include updated upper limits on …

Buckling Patterns And Mechanics Of Thin Interfacial Polymer Films, Monica M. Ripp

Dissertations - ALL

Thin elastic solids are easily deformed and will readily collapse into complex buckling modes. They can also transition between distinct buckling modes when the confining forces evolve over time, forming a variety of robust and striking patterns. Here we explore how thin interfacial films and the buckling modes they present couple with evolving macroscopic forces and how multi-scale features of the systems give rise to patterns.

In the indentation of a circular film floating on a liquid bath three buckling modes arise: wrinkling, crumpling, and folding. This work shows that striking transitions between these states accompany four regimes in the …

Direct Single Molecule Imaging Of Enhanced Diffusion For Enzymes And Enzyme-Conjugated Dna Origami, Mengqi Xu

Dissertations - ALL

Enzymes have been shown to diffuse faster in the presence of their substrates. Recently, we revealed new insights into this process of enhanced diffusion using single-particle tracking (SPT) with total internal reflection fluorescence (TIRF) microscopy. We found that the mobility of individual enzymes was enhanced three-fold in the presence of the substrate, and the motion remained Brownian. We showed that the relative increase in diffusion is independent of the total enzyme concentrations; and the oligomerization state of enzymes did not change during the catalytic turnover. These experiments ruled out the possibility that the enhanced enzyme diffusion was caused by the …

First Measurement Of B(Ξc0 → Π−Λ+C ), Michael Kent Wilkinson

Dissertations - ALL

The first measurement of the branching fraction of the Ξc0 baryon in its decay to π− and Λ+c hadrons, B(Ξc0 → π−Λ+c ), is presented. This measurement was conducted with the LHCb detector, located on the Large Hadron Collider, using 13 TeV proton-proton collisions. There have been a number of theoretical predictions for the size of this branching fraction, spanning more than an order of magnitude; this large difference is primarily due to differing assumptions about the internal interactions contributing to the decay. The branching fraction measured here provides the first experimental evidence for the nature of these interactions; it …

A Solid-State Phase Camera For Advanced Gravitational Wave Detectors, Erik Muniz

Dissertations - ALL

I present a novel way of wavefront sensing using a commercially available, continuouswavetime-of- ight camera with QVGA-resolution. This CMOS phase camera is capable of sensing externally modulated light sources with frequencies up to 100 MHz. The high-spatial-resolution of the sensor, combined with our integrated control electronics, allows the camera to image power modulation index as low as -62 dBc/second/pixel. The phase camera is applicable to problems where alignment and mode-mismatch sensing is needed and suited for diagnostic and control applications in gravitationalwave detectors. Specically, I explore the use of the phase camera in sensing the beat signals due to thermal …

Observation Of Ω Contribution In The C1(3872) → Π+Π−J/Ψ Decays, Baasansuren Batsukh

Dissertations - ALL

Resonant structure in the dipion mass spectrum produced via \decay{\Bu}{\X\Kp}, \decay{\X}{\jpsi \pip \pim}, with \decay{\jpsi}{\mu^+\mu^-} is analyzed using Run 1 and Run 2 data samples from the LHCb experiment. The spectrum is dominated by $\rhoz\to\pi^+\pi^-$, but cannot be described by this contribution alone. A significant $\omega\to\pi^+\pi^-$ contribution, interfering with $\rhoz$, is observed for the first time. This is a more significant observation ($>7.1\sigma$) of $\X\to\omega\jpsi$ decays, than previously achieved with $\omega\to\pi^+\pi^-\pi^0$ decays. The relative contribution of $\omega$ to the total $\X\to\pi^+\pi^-\jpsi$ rate is at the level expected from the measured $\X\to(\omega\to\pi^+\pi^-\pi^0)\jpsi$ rate, if the interference between the $\rho^0$ and …

Utilizing Parity Violating Electron Scattering As A Probe To Measure The Neutron Radius Of 208-Pb, David Eric King

Dissertations - ALL

The Lead Radius Experiment 2 (PREX-II) and Calcium Radius Experiment (CREX) carried out in Hall A of the Thomas Jefferson National Accelerator Facility were designed to measure the neutron skins of 208-Pb and 48-Ca nuclei by measuring the parity-violating asymmetry APV of the elastic scattering of polarized electrons on 208-Pb and 48-Ca targets. In order to achieve a precision measurement of the neutron skins of 208-Pb and 48-Ca it is imperative to maintain precise control over many experimental parameters–one of which is a precision measurement of the electron beam polarization (which is the largest contributor to experimental error making control …

Temperature-Immune Self-Referencing Fabry–Pérot Cavity Sensors, Hengky Chandrahalim, Jonathan W. Smith

AFIT Patents

A passive microscopic Fabry-Pérot Interferometer (FPI) sensor an optical fiber a three-dimensional microscopic optical structure formed on a cleaved tip of an optical fighter that reflects a light signal back through the optical fiber. The reflected light is altered by refractive index changes in the three-dimensional structure that is subject to at least one of: (i) thermal radiation; and (ii) volatile organic compounds.

Design And Construction Of A Modular Nai(Tl) Detector Array For Use In The Parity- And Time Reversal Violation Measurements For Noptrex, Jon Mills, Jason Fry

Posters-at-the-Capitol

The goal of the NOPTREX collaboration is to probe the Standard Model by utilizing the properties of low energy neutron-nucleus resonances to find evidence of parity- and time-reversal-odd violations. In order to conduct these sensitive experiments, it is needed to design and simulate an array of modular, high precision NaI(Tl) detectors. These detectors will be designed to operate in both pulse and current modes. We have tentative beam time at LANSCE to perform a search for new parity violation in heavy nuclei as candidates for time reversal and to perform a research and development effort on the n+d=t+gamma experiment. We …

Droplet-Based Fuel Property Measurements, Wanjun Dang

LSU Doctoral Dissertations

Ongoing work to find renewable biofuels to function as drop-in replacements or blending components with gasoline has identified a large number of fuel candidates. Given the vast number of potential biomass-derived fuel molecules and limited sample sizes, screening tools are required to down-select candidate fuels having desired physical properties to ensure good engine performance. This work investigates approaches for rapid screening of candidate fuels using micro-liter sample sizes targeting four properties -- surface tension, viscosity, heat of vaporization (HOV), and vapor pressure. Measurement techniques for fuel properties are developed based on unit phenomena for liquid fuel droplets including droplet oscillation …

Sufficient Condition For The Possibility Of Completing The Pursuit, Nodirbek Umrzaqov

Scientific Bulletin. Physical and Mathematical Research

In this paper, the problem of chase is represented by a system of linear differential equations of motion dynamics. In this case, there is an integral limit to the control parameter of the evader, and a geometric limit to the control parameter of the pursuer. The pursuer is allowed to use the control that the fugitive has used so far to build his control. There are enough conditions for the game to end even if it starts from any starting point. An algorithm for constructing the control function of the pursuer is defined. It should also be noted that the …

Fast Statistical Methods For The Global Qcd Analysis Of The Proton Structure, Xiaoxian Jing

Physics Theses and Dissertations

Parton distribution functions (PDFs) quantify probabilities to find partons (quarks and gluons) in a hadron as a function of the fraction x of the hadron’s momentum carried by the parton at a given energy scale. PDFs play a critical role in precision tests of the Standard Model in Higgs boson production and other electroweak processes at the Large Hadron Collider (LHC), and in searches for physics beyond the Standard Model. PDFs are obtained by the global QCD analysis, which fits theoretical predictions to experimental measurements. PDF fitting and post-analysis are computationally intensive. This dissertation discusses fast statistical methods for the …

Discovery Of An Olivine-Type Lithium Manganese Thiophosphate, Limnps4,: Via A Building Block Approach, Srikanth Balijapelly, Kartik Ghosh, Aleksandr V. Chernatynskiy, Amitava Choudhury

Physics Faculty Research & Creative Works

An olivine-type orthothiophospate LiMnPS4 has been synthesized for the first time through a building block approach by reacting preformed ternary lithium thiophospate with MnCl2. Diffuse reflectance measurements show an optical band gap of 2.36 eV, which is further confirmed by DFT calculations. Irreversible weak ferromagnetic ordering and metamagnetism are verified through preliminary magnetic measurements.

Evaluation And Improvement Of Nuclear Security Measures At A Radiological Facility In Morocco, Halima Jemmal, Abdelmajid Choukri, Mohammed Mouhib

International Journal of Nuclear Security

Nuclear security combines both concepts of physical security and security culture within a nuclear facility to protect people, property, society and the environment from harmful effects of ionization radiation. Physical security means prevention, detection, and response to unauthorized removal, sabotage, and/or illegal transfer involving radioactive sources and nuclear material. Nuclear security culture is the human factor within the nuclear field which is considered a principal means to support and enhance nuclear security system. This paper presents a study of nuclear security system already established within a radiological facility considering concepts such as: deter, detect, delay, and response layers. This study …

Spin-Dependent Electronic Transport In Noncollinear Antiferromagnetic Antiperovskites, Gautam Gurung

Department of Physics and Astronomy: Dissertations, Theses, and Student Research

Spin-dependent properties are the heart of spintronic devices. Spintronics exploits electron’s spin, in addition to charge, to process and store the information. Recently, antiferromagnetic (AFM) spintronics has emerged as a subfield of spintronics, where an AFM order parameter (the Néel vector) is exploited to control spin-dependent transport properties. Due to being robust against magnetic perturbations, producing no stray fields, and exhibiting ultrafast dynamics, antiferromagnets can serve as promising functional materials for spintronic applications.

Among antiferromagnets, high Néel temperature noncollinear antiperovskites ANMn₃ (A = Ga, Ni, Sn, and Pt) are interesting due to their magnetic group symmetry supporting non-trivial spin-dependent …