Other Physics Commons^™

Enhancement Of Heat Transfer In Elastico-Viscous Fluid Due To Nanoparticles, Where The Fluid Is Impinging Obliquely To The Stretchable Surface: A Numerical Study, Tariq Javed, Abuzar Ghaffari, Tasawar Hayat

Applications and Applied Mathematics: An International Journal (AAM)

This article addresses the two-dimensional oblique stagnation point flow of non-Newtonian fluid in the presence of nanoparticles. Constitutive equations of Walter-B fluid are employed in the mathematical development of the relevant problems. Mathematical formulation includes the Brownian motion and thermophoresis effects. The resulting nonlinear system of equations are analyzed through Chebyshev Spectral Newton Iterative Scheme (CSNIS). A comparative study of present results through tabular values has been made with the previous results in a limiting sense and an excellent agreement is noted. It is also found that in near stagnation point region, the heat transfer rate and mass diffusion flux …

Lrs Bianchi Type-I Cosmology With Gamma Law Eos In F(R; T) Gravity, Pratishtha Shukla, Amritha Jayadev

Applications and Applied Mathematics: An International Journal (AAM)

We have studied the locally rotationally symmetric (LRS) Bianchi type-I line element in f(R; T) (R is the Ricci scalar and T is the trace of the stress energy tensor) theory of gravity in presence of EoS parameter. The simplest case of f(R; T) gravity, i.e. first choice, is considered. The “gamma-law” equations of state are considered to explore the role of particle creation in the early universe. The exact solutions of the field equations are obtained using the scalar expansion proportional to the shear. The physical and kinematical properties of the model are studied.

Effect Of Fluid Suction On An Oscillatory Mhd Channel Flow With Heat Transfer, N. Ahmed, A. H. Sheikh, D. P. Barua

Applications and Applied Mathematics: An International Journal (AAM)

Magnetohydrodynamics (MHD) is generally concerned with the study of the magnetic properties (behaviour) of electrically conducting fluids (plasmas, liquid metals etc.) moving in an electromagnetic field. The importance of the concept of MHD in various fields such as astrophysics, bio-medical research, missile technology and geophysics motivates the modelling and investigation of MHD flow and transport problems. The role of fluid suction is paramount in laminar flow control and has wide applications in fields such as aeronautical engineering, automobile engineering and rocket science. This fact inspires the study of the effects of fluid suction in flow and transport models. Time dependent …

Thermal Vibration Of Magnetostrictive Functionally Graded Material Shells With The Transverse Shear Deformation Effects, C. C. Hong

Applications and Applied Mathematics: An International Journal (AAM)

The transverse shear deformation effect on the functionally graded material (FGM) circular cylindrical shells with mounted magnetostrictive layer under thermal vibration is investigated by using the generalized differential quadrature (GDQ) method. In the time dependent of displacement field, the first order shear deformation theory (FSDT) is used. The dynamic equilibrium differential equations with displacements and shear rotations of FGM shells under the magnetostrictive load and thermal load are normalized into the dynamic discrete equations. The computational solutions for thermal stresses and center deflections of magnetostrictive FGM circular cylindrical shells with four edges in simply supported boundary conditions are obtained. Some …

On The Global Existence And Boundedness Of Solutions Of Nonlinear Vector Differential Equations Of Third Order, Timur Ayhan, Cemil Tunç

Applications and Applied Mathematics: An International Journal (AAM)

In this paper, we give some criteria to ensure the global existence and boundedness of solutions to a kind of third order nonlinear vector differential equations. By using the Lyapunov's direct method, we obtain a new result on the topic and give an example for the illustrations. Our result includes, completes and improves some earlier results in the literature.

Bianchi Type-I Hyperbolic Models With Perfect Fluid And Dark Energy In Bimetric Theory Of Gravitation, M. S. Borkar, S. S. Charjan, V. V. Lepse

Applications and Applied Mathematics: An International Journal (AAM)

Three different Bianchi type-I cosmological models as related to perfect fluid, with quintessence and with Chaplygin gas, in bimetric theory of gravitation have been deduced. The perfect fluid model has hyperbolic geometry and all its physical parameters are also hyperbolic in nature and therefore they have been studied from hyperbolic geometric view point. All these models are isotropize and shear-less. Other geometrical and physical behaviors of the models have also been studied. The hyperbolic geometric view point of the models will be helpful to the people who use observational data to search for such type of geometry.

Magnetic Reconnection In Small And Large Scales On The Sun, Xin Chen

Dissertations

Almost all solar activities observed are related to the solar magnetic field, especially the topological restructuring of magnetic fields, the so-called magnetic reconnection in solar physics. They are occurring at different scales related to various phenomena, during minimum or maximum of the solar cycle, from the photosphere to the solar corona.

For small-scale activities, type II spicules which display high velocity upflows observed at the limb, have the most possible underlying driving mechanism of magnetic reconnection. A set of tools is developed for detecting small-scale solar magnetic cancellations and the disk counterpart of type II spicules (the so-called Rapid Blueshifted …

New Facet Of Solar Activities Revealed By High-Resolution Imaging At He I 10830 Å, Zhicheng Zeng

Dissertations

Major solar activities such as major flares and associated coronal mass ejections (CMEs), have a great impact on space weather, which requires us to develop the ability to predict them. Despite the extensive studies already made, however, many basic processes, such as energy accumulation processes in solar active regions and the triggering mechanism of solar activities, are still not well understood.

One reason why the basic processes are hard to be understood is that the large-scale activities are complicated, involving many small-scale energy releases, making it hard to understand the basic picture of the events. Small-scale solar activities, such as …

Radiative Properties Of Silicon Related Materials, Scott Sanowitz

Theses

The objective of this thesis is to study the optical properties of silicon, as a function of temperature, in the infrared range of wavelengths. The wavelength range, considered in this study, is between 1 micron and 20 microns. The temperature range observed is from 50 degrees Celsius to 1000 degrees Celsius. Varying wafer thickness and doping are taken into account. The thickness of the native oxide, silicon dioxide, must be taken into account as well as its orientation (front side versus back side). The effect of layering wafers one onto another is investigated. It is shown that all these parameters …

Automated Sea State Classification From Parameterization Of Survey Observations And Wave-Generated Displacement Data, Jason A. Teichman

LSU New Orleans Theses and Dissertations

Sea state is a subjective quantity whose accuracy depends on an observer’s ability to translate local wind waves into numerical scales. It provides an analytical tool for estimating the impact of the sea on data quality and operational safety. Tasks dependent on the characteristics of local sea surface conditions often require accurate and immediate assessment. An attempt to automate sea state classification using eleven years of ship motion and sea state observation data is made using parametric modeling of distribution-based confidence and tolerance intervals and a probabilistic model using sea state frequencies. Models utilizing distribution intervals are not able to …

The Millikan Oil Drop Experiment: A Simulation Suitable For Classroom Use, Benjamin Hogan, Javier E. Hasbun

Georgia Journal of Science

Due to advancements in computing techniques it has become possible to extend the accessibility of physics experiments across the physics curriculum by means of computational simulations. The widespread availability of computers in modern classrooms provides virtual access to hands-on physics, chemistry, and biology experiments, among others. Here, specifically, we consider Robert Millikan’s famous oil drop experiment. This experiment requires equipment that can be dangerous and expensive. A more practical approach is achieved via a computer simulation, a useful and a universally available alternative. The goal is to encourage scientific thinking, literacy, and innovation while promoting a free network of academic …

A Cylindrically Symmetric “Micro-Mott” Electron Polarimeter, Nathan B. Clayburn, Evan M. Brunkow, S. J. Burtwistle, George H. Rutherford, Timothy J. Gay

Timothy J. Gay Publications

A small, novel, cylindrically symmetric Mott electron polarimeter is described. The effective Sherman function, S_eff , or analyzing power, for 20 kV Au target bias with a 1.3 keV energy loss window is 0.16 ± 0.01, where uncertainty in the measurement is due primarily to uncertainty in the incident electron polarization. For an energy loss window of 0.5 keV, S_eff reaches its maximum value of 0.24 ± 0.02. The device’s maximum efficiency, I/I_o, defined as the detected count rate divided by the incident particle rate, is 3.7 ± 0.2 × 10^{− …}

Particle Image Velocimetry Design & Installation, Zach Ritchie

Mechanical Engineering Undergraduate Honors Theses

This work will mainly focus on the design, construction, and installation of the Particle Image Velocimetry (PIV) system in the Chemical Hazards Research Center wind tunnel. The PIV system utilizes a Class IV (double pulsed) laser, optics to produce a light sheet, timing circuitry, and a high-resolution camera (with buffered output) to measure a system’s velocity (two-dimensional) field by determining the displacement of particles over the time between laser pulses. For maximum mobility and functionality, the PIV system was installed in the center of the tunnel on a moveable cart with the laser and camera mounted to an adjustable support. …

The Singing Cymbal: Is It Really Photon Momentum?, Thomas R. Moore, Samantha Collin, Nikki Etchenique

Student-Faculty Collaborative Research Publications

A simple demonstration that is occasionally used in the classroom to show that light carries momentum involves making an orchestral cymbal audibly ring using light from a common photoflash. A metal plate or a piece of foil can also be used, however, it appears that many people use a cymbal because the sound is easily heard at a reasonable distance. It is such an impressive example of the effects attributable to photon momentum that it is posted on the CERN website for educational under the name “singing cymbal.” Although it is an impressive demonstration, a series of simple classroom experiments …

Electromagnetic Properties Of Metal-Dielectric Media And Their Applications, Shravan Rakesh Animilli

Doctoral Dissertations

The main objective of this dissertation is to investigate nano-structured random composite materials, which exhibit anomalous phenomena, such as the extraordinary enhancements of linear and non-linear optical processes due to excitation of collective electronic states, surface plasmons (SP). The main goal is to develop a time and memory efficient novel numerical method to study the properties of these random media in three dimensions (3D) by utilization of multi core processing and packages such as MPI for parallel execution. The developed numerical studies are then utilized to provide a comprehensive characterization and optimization of a surface plasmon enhanced solar cell (SPESC) …

New Type Of Al-Based Decagonal Quasicrystal In Al60Cr20Fe10Si10 Alloy, Zhanbing He, Haikun Ma, Hua Li, Xingzhong Li, Xiuliang Ma

Nebraska Center for Materials and Nanoscience: Faculty Publications

A new kind of decagonal quasicrystal (DQC) with a periodicity of 1.23 nm was observed in the as-cast quaternary Al₆₀Cr₂₀Fe₁₀Si₁₀ alloy. The intensity distribution of some spots in the selected-area electron diffraction pattern along the tenfold zone axis was found to be different from other Al-based DQCs. High-angle annular dark-field scanning transmission electron microscopy was adopted to reveal the structural features at an atomic level. Both the tenfold symmetry and symmetry-broken decagonal (D) clusters of 1.91 nm in diameter were found, but with structural characteristics different from the corresponding D clusters in the …

Tests For Intrinsicness Tested, Kelvin J. Mcqueen, René Van Woudenberg

Philosophy Faculty Articles and Research

Various tests have been proposed as helps to identify intrinsic properties. This paper compares three prominent tests (we call them Perfect Duplication, Real Change, and Lonely) and shows that they fail to pass adequate verdicts on a set of three properties. The paper examines whether improved versions of the tests can reduce or remove these negative outcomes. We reach the sceptical conclusion that whereas some of the tests must be discarded as inadequate because they don’t yield definite results, the remaining tests depend for their application on the details of fundamental particle physics so much so that they cannot be …

Novel Electrolytes For Use In New And Improved Batteries: An Nmr Study, Marc B. Berman

Dissertations, Theses, and Capstone Projects

This thesis focuses on the use of nuclear magnetic resonance (NMR) spectroscopy in order to study materials for use as electrolytes in batteries. The details of four projects are described in this thesis as well as a brief theoretical background of NMR. Structural and dynamics properties were determined using several NMR techniques such as static, MAS, PFG diffusion, and relaxation to understand microscopic and macroscopic properties of the materials described within. Nuclei investigate were 1H, 2H, 7Li, 13C, 19F, 23Na, and 27Al. The first project focuses on an exciting new material to be used as a solid electrolyte membrane. T. …

Terahertz Wireless Communication Through Atmospheric Atmospheric Turbulence And Rain, Jianjun Ma

Dissertations

This dissertation focusses on terahertz (THz) wireless communication technology in different weather conditions. The performance of the communication links is mainly studied under propagation through atmospheric turbulence and rain. However, as real outdoor weather conditions are temporally and spatially varying, it is difficult to obtain reproducible atmospheric conditions to verify results of independent measurements making it a challenge to measure and analyze the impact of outdoor atmospheric weather on communication links. Consequently, dedicated indoor weather chambers are designed to produce controllable weather conditions to emulate the real outdoor weather as closely as possible. To emulate turbulent air conditions, an enclosed …

Opto-Mechanical Design Of Synchrotron Radiation-Based Far-Infrared Spectroscopic Ellipsometer With Strong Magnetic-Field, Ahmad Abbas Chaudhry

Theses

The objective of this dissertation is to present opto-mechanical design of a synchrotron radiation based far-infrared spectroscopic ellipsometer with a strong external magnetic-field capability. Since high magnetic field has enabled major breakthrough in science such instrument will be highly important to the field of condensed matter physics and characterization of advanced electronic materials. This instrument will be installed at the multi-User facility with the most advanced synchrotron light source: Natonal Synchrotron Source (NSLS-II) at Brookhaven National Laboratory (BNL).The proposed here instrument is capable to measure full Mueller matrix spectroscopic ellipsometry spectra in high magnetic fields of up to 9 Tesla. …

Vortex Circulation And Polarity Patterns In Closely Packed Cap Arrays, Robert Streubel, Florian Kronast, Christopher F. Reiche, Thomas Mühl, Anja U.B. Wolter, Oliver G. Schmidt, Denys Makarov

Robert Streubel Papers

We studied curvature-driven modifications to the magnetostatic coupling of vortex circulation and polarity in soft-magnetic closely packed cap arrays. A phase diagram for the magnetic remanent/transition states at room temperature as a function of diameter and thickness was assembled. For specimens with vortex remanent state (40 nm-thick Permalloy on 330 nm spherical nanoparticles), both vortex circulation and polarity were visualized. Intercap coupling upon vortex nucleation leads to the formation of vortex circulation patterns in closely packed arrays. The remanent circulation pattern can be tailored choosing the direction of the applied magnetic field with respect to the symmetry axis of the …

Drag Reduction Using Graphene In Viscous Laminar Flow With Water And Isopropanol, Jessica M. Patalano, Akm Newaz Dr.

STAR Program Research Presentations

America has over 2.6 million miles of pipeline for the transportation of energy products, such as liquid petroleum and natural gas. Friction is one of the main sources for energy dissipation at liquid/solid interfaces that limits the transport of a fluid through a cylindrical pipe or tube. In order to make these pipelines more efficient and enhance the flow of these materials, it is necessary to find a coating material that reduces the frictional drag. The ideal material would reduce the drag between the fluid and solid interface while being easily synthesizable on the surface. The goal of this project …

Electron Diffraction Study Of Cobalt-Rich Hf-Co, Xingzhong Li, Yunlong Jin, Jeffrey E. Shield, Ralph Skomski, David J. Sellmyer

Nebraska Center for Materials and Nanoscience: Faculty Publications

Intermetallic compounds having compositions from HfCo₄ to HfCo₈ were investigated by transmission electron microscopy, selected-area electron diffraction, and energy-dispersive x-ray spectroscopy. A major crystalline phase, closely related to the orthorhombic Zr₂Co₁₁ phase in structure, has been observed in the samples with the composition ranges from HfCo₆ to HfCo₈. The phase, referred to as either Hf₂Co₁₁ or HfCo₇ phase in the literature, is actually one common phase, having a broad composition range and referred to as μ-phase in the present paper. In addition to the μ-phase, we …

Method For Monitoring Gaas Photocathode Heat Cleaning Temperature, Nathan B. Clayburn, Kenneth Wayne Trantham, M. Dunn, Timothy J. Gay

Timothy J. Gay Publications

Before a GaAs photocathode can be activated to achieve a negative electron affinity condition, the GaAs crystal must be cleaned. This is most commonly done by ohmic, radiative, or electron bombardment heating. We report a new technique to monitor the temperature of heated GaAs photocathodes by observation with a camera. The method is robust and yields the same temperatures for different GaAs samples heated using different methods in different mounting configurations.

Phase Separation In Lufeo3 Films, Shi Cao, Xiaozhe Zhang, Kishan Sinha, Wenbin Wang, Jian Wang, Peter A. Dowben, Xiaoshan Xu

Peter Dowben Publications

The structural transition at about 1000°C, from the hexagonal to the orthorhombic phase of LuFeO₃, has been investigated in thin films of LuFeO₃. Separation of the two structural phases of LuFeO₃ occurs on a length scale of micrometer, as visualized in real space using X-ray photoemission electron microscopy. The results are consistent with X-ray diffraction and atomic force microscopy obtained from LuFeO₃ thin films undergoing the irreversible structural transition from the hexagonal to the orthorhombic phase of LuFeO₃, at elevated temperatures. The sharp phase boundaries between the structural phases are observed to …

Influence Of Steric Hindrance On The Molecular Packing And The Anchoring Of Quinonoid Zwitterions On Gold Surfaces, Minghui Yuan, Iori Tababe, Jean-Marie Bernard- Schaaf, Qin-Yin Shi, Vicki Schlegel, Rachel Schurhammer, Peter A. Dowben, Bernard Doudin, Lucie Routaboul, Pierre Braunstein

Peter Dowben Publications

Driven by the huge potential of engineering the molecular band offset with highly dipolar molecules for improving charge injection into organic electrics, the anchoring of various N-alkyl substituted quinonoid zwitterions of formula C₆H₂ (···NHR)₂ (···O)₂ (R = iPr, Cy, CH₂CH(Et)CH₂CH₂CH₂CH₃,. . .) on gold surfaces is studied. The N–Au interactions result in an orthogonal arrangement of the zwitterions cores with respect to the surface, and stabilize adsorbed compact rows of molecules. IR spectroscopy is used as a straightforward diagnostic tool to validate the presence of …

On The Ising Character Of The Quantum-Phase Transition In Lihof4, Ralph Skomski

Ralph Skomski Publications

It is investigated how a transverse magnetic field affects the quantum-mechanical character of LiHoF₄, a system generally considered as a textbook example for an Ising-like quantum-phase transition. In small magnetic fields, the low-temperature behavior of the ions is Ising-like, involving the nearly degenerate low-lying J_z = ± 8 doublet. However, as the transverse field increases, there is a substantial admixture of states having | J_z | < 8. Near the quantum-phase-transition field, the system is distinctively non-Ising like, and all J_z eigenstates yield ground-state contributions of comparable magnitude. A classical analog to this mechanism is the micromagnetic single point in magnets with uniaxial anisotropy. Since Ho³⁺ has …

Low-Temperature Fcc To L10 Phase Transformation In Copt(Bi) Nanoparticles, Frank M. Abel, Vasilis Tzitzios, David J. Sellmeyer, George C. Hadjipanayis

Nebraska Center for Materials and Nanoscience: Faculty Publications

This work is focused on the effects of Bi substitution on the synthesis of CoPt nanoparticles with the L1₀ structure using a modified organometallic approach. The structural and magnetic properties of the nanoparticles have been studied and compared directly with those of CoPt nanoparticles synthesized by the same tech- nique but in the absence of Bi substitution. The as-synthesized particles at 330 ◦C have an average size of 11.7 nm and a partially ordered L10 phase with a coercivity of 1 kOe. The coercivity is increased to 9.3 kOe and 12.4 kOe after annealing for 1 hour at 600 …

Analysis Of Solar Photovoltaic And Wind Power Potential In Afghanistan, Ahmad Murtaza Ershad, Robert J. Brecha, Kevin P. Hallinan

Physics Faculty Publications

Afghanistan has a need for increased access to energy to enable development. In this paper we analyze the potential for large-scale grid-connected solar photovoltaic (PV) and wind power plants in two of Afghanistan's most populous provinces (Balkh and Herat) to meet a large fraction of growing electricity demand. The results presented here represent the first quantitative analysis of potential capacity factors and energy yields of power plants in the country using measured wind speed and typical solar radiation data. Variability of resources is also investigated by comparing temporal profiles with those of electricity demand, using residual load duration curves to …

Modification Of The G-Phonon Mode Of Graphene By Nitrogen Doping, Pavel V. Lukashev, Liuyan Zhao, Tula R. Paudel, Theanne Schiros, Noah Hurley, Evgeny Y. Tsymbal, Aron Pinczuk, Abhay Pasupathy, Rui He

Nebraska Center for Materials and Nanoscience: Faculty Publications

The effect of nitrogen doping on the phonon spectra of graphene is analyzed. In particular, we employ first-principles calculations and scanning Raman analysis to investigate the dependence of phonon frequencies in graphene on the concentration of nitrogen dopants. We demonstrate that the G phonon frequency shows oscillatory behavior as a function of nitrogen concentration. We analyze different mechanisms which could potentially be responsible for this behavior, such as Friedel charge oscillations around the localized nitrogen impurity atom, the bond length change between nitrogen impurity and its nearest neighbor carbon atoms, and the long-range interactions of the nitrogen point defects. We …