Digital Commons Network^™

On Atmospheric Lapse Rates, Nihad E. Daidzic

International Journal of Aviation, Aeronautics, and Aerospace

We have derived and summarized and most important atmospheric temperature lapse rates. ALRs essentially govern vertical atmospheric air stability and creation of some cloud types. The sensitivity analysis of various atmospheric lapse rates and their dependence on actual ideal-gas air properties and gravitational attraction was conducted for the first time to the best of our knowledge. SALR, which has DALR as the upper asymptote, showed steepest decrease at around 9 degrees Celsius then flattening out and apparently approaching another asymptotic solution which has not been investigated as it falls outside of the terrestrial temperature range. ISA lapse rates are adopted …

Nonlinear Sliding Mode Observer Applied To Microalgae Growth, Rebecca J. Griffith

Doctoral Dissertations and Master's Theses

Modeling biological processes, such as algae growth, is an area of ongoing research. The ability to understand the multitude of parameters that influence this system provides a platform for better understanding the dynamics of microalgae growth. Empirical modeling efforts look to understand sources of driving nutrients that influence harmful algal blooms (HABs). These harmful algal blooms are dense aggregates that have an increasingly negative impact on local economics, marine and freshwater systems, and public health. They result from a high influx of nitrogen and nutrients that drive the algae biomass to exponentially grow. This growth blocks out the sun, potentially …

Vortex Structures Inside Spherical Mesoscopic Superconductor Plus Magnetic Dipole, A. Ludu

Publications

We investigate the existence of multivortex states in a superconducting mesoscopic sphere with a magnetic dipole placed at the center. We obtain analytic solutions for the order parameter inside the sphere through the linearized Ginzburg-Landau (GL) model, coupled with mixed boundary conditions, and under regularity conditions and decoupling coordinates approximation. The solutions of the linear GL equation are obtained in terms of Heun double confluent functions, in dipole coordinates symmetry. The analyticity of the solutions and the associated eigenproblem are discussed thoroughly. We minimize the free energy for the fully nonlinear GL system by using linear combinations of linear analytic …

Floating Active Baffles, System And Method Of Slosh Damping Comprising The Same, Dae Won Kim, Rudy L. Baum, Vijay Santhanam, Balaji Sivasubramanian, Sathya Gangadharan

Publications

This disclosure provides a system for damping slosh of a liquid within a tank, a baffle for use in the system, and a method of damping slosh using the system. The system includes a plurality of baffles. Each baffle has a body configured to substantially float upon the liquid. Each baffle also has an activation material received along at least a portion of the body. The activation material is magnetically reactive provided in a quantity sufficient to enable the body to be manipulated in the presence of a magnetic field (M). The system further includes an actuator configured to pro­vide …

Impacts Of Anisotropy, Wave Heating, And Neutral Winds On High-Latitude Ionospheric Dynamics, Meghan R. Burleigh

Doctoral Dissertations and Master's Theses

Significant amounts of ionospheric plasma can be transported to high altitudes (ion upflow) in response to a variety of plasma heating and uplifting processes such as DC electric fields and precipitation. Once ions have been lifted to high altitudes, transverse ion acceleration by broadband ELF waves can give the upflowing ions sufficient energy for the mirror force to propel these ions to escape into the magnetosphere (ion outflow). In order to accurately examine the connection between upflow and outflow processes, a new two dimensional, anisotropic fluid model is developed.

The new model, named GEMINI-TIA, is based on a Bi-Maxwellian distribution …

Effect Of Chemistry On Electrodynamics In The Martian Dynamo Region, Morgan M. Matheny

Doctoral Dissertations and Master's Theses

Electromagnetic interactions between Mars remnant crustal magnetic fields and solar and planetary ions lead to time and space variations of the ionosphere. In this work, we continue the investigations started by Riousset et al. [2013] and address the effect of chemistry on ion populations in the dynamo region, where ion dynamics are driven by collisions while electrons are still mostly magnetized. We adopt a mesoscale model to simulate dynamics of electrons and ions in the upper atmosphere (100–400 km). Our approach focuses on numerical studies using the Martian Multifluid Magnetohy drodynamic (MF-MHD) Model (M4). The dynamo is a region which …

Nonlinear Acoustic Waves Generated By Surface Disturbances And Their Effect On Lower Thermospheric Composition, Benedict Piñeyro

Doctoral Dissertations and Master's Theses

Recent nonlinear atmospheric models have provided important insight into acoustic waves generated by seismic events, which may steepen into shocks or saw-tooth trains while also dissipating strongly in the thermosphere. Although they have yielded results that agree with observations of ionospheric perturbations, dynamical models for the diffusive and stratified lower thermosphere often use single gas approximations with height-dependent physical properties (e.g. mean molecular weight, specific heats) that do not vary with time (fixed composition). This approximation is simpler and less computationally expensive than a true multi-fluid model, yet captures the important physical transition between molecular and atomic gases in the …

A Study Into Data Analysis Of Varying Types Of Langmuir Probes, William Merritt

Doctoral Dissertations and Master's Theses

Langmuir probes are ubiquitously used for in-situ measurements of plasma parameters. These probes have been placed on many different platforms, including experimental sounding rockets for measurements in mesosphere-lower-thermosphere, and also onboard satellites to obtain data sets over an extended period of time in the ionosphere. To accommodate such different situations, many different variations of the Langmuir probe design have been made. This thesis covers two such implementations, as well as the data analysis and issues that can arise with such instruments. The first of these implementations is a set of sweeping Langmuir probes on the Floating Potential Measurement Unit (FPMU) …

Patient-Specific Multiscale Computational Fluid Dynamics Assessment Of Embolization Rates In The Hybrid Norwood: Effects Of Size And Placement Of The Reverse Blalock–Taussig Shunt, Ray Prather, John Seligson, Marcus Ni, Eduardo Divo, Alain J. Kassab, William Decampli

Publications

The hybrid Norwood operation is performed to treat hypoplastic left heart syndrome. Distal arch obstruction may compromise flow to the brain. In a variant of this procedure, a synthetic graft (reverse Blalock–Taussig shunt) is placed between the pulmonary trunk and innominate artery to improve upper torso blood flow. Thrombi originating in the graft may embolize to the brain. In this study, we used computational fluid dynamics and particle tracking to investigate the patterns of particle embolization as a function of the anatomic position of the reverse Blalock–Taussig shunt. The degree of distal arch obstruction and position of particle origin influence …

Godunov-Type Upwind Flux Schemes Of The Two-Dimensional Finite Volume Discrete Boltzmann Method, Leitao Chen, Laura Schaefer

Publications

A simple unified Godunov-type upwind approach that does not need Riemann solvers for the flux calculation is developed for the finite volume discrete Boltzmann method (FVDBM) on an unstructured cell-centered triangular mesh. With piecewise-constant (PC), piecewise-linear (PL) and piecewise-parabolic (PP) reconstructions, three Godunov-type upwind flux schemes with different orders of accuracy are subsequently derived. After developing both a semi-implicit time marching scheme tailored for the developed flux schemes, and a versatile boundary treatment that is compatible with all of the flux schemes presented in this paper, numerical tests are conducted on spatial accuracy for several single-phase flow problems. Four major …

Error Analysis Of Multi-Needle Langmuir Probe Measurement Technique, Aroh Barjatya, William Merritt

Publications

Multi-needle Langmuir probe is a fairly new instrument technique that has been flown on several recent sounding rockets and is slated to fly on a subset of QB50 CubeSat constellation. This paper takes a fundamental look into the data analysis procedures used for this instrument to derive absolute electron density. Our calculations suggest that while the technique remains promising, the current data analysis procedures could easily result in errors of 50% or more. We present a simple data analysis adjustment that can reduce errors by at least a factor of five in typical operation.

Global Formulation And Control Of A Class Of Nonholonomic Systems, Muhammad Rehan

Doctoral Dissertations and Master's Theses

This thesis study motion of a class of non-holonomic systems using geometric mechanics, that provide us an efficient way to formulate and analyze the dynamics and their temporal evolution on the configuration manifold. The kinematics equations of the system, viewed as a rigid body, are constrained by the requirement that the system maintain contact with the surface. They describe the constrained translation of the point of contact on the surface. In this thesis, we have considered three different examples with nonholonomic constraint i-e knife edge or pizza cutter, a circular disk rolling without slipping, and rolling sphere. For each example, …

An Asymptotic Analysis For Generation Of Unsteady Surface Waves On Deep Water By Turbulence, Shahrdad Sajjadi

Publications

The detailed mathematical study of the recent paper by Sajjadi, Hunt and Drullion (2014) is presented. The mathematical developement considered by them, for unsteady growing monochromatic waves is also extended to Stokes waves. The present contribution also demonstrates agreement with the pioneering work of Belcher and Hunt (1993) which is valid in the limit of the complex part of the wave phase speed c_i ↓ 0. It is further shown that the energy-transfer parameter and the surface shear stress for a Stokes wave reverts to a monochromatic wave when the second harmonic is excluded. Furthermore, the present theory can …

A Comparison Of Online, Video Synchronous, And Traditional Learning Modes For An Introductory Undergraduate Physics Course, Emily K. Faulconer, John C. Griffith, Beverly Wood, Donna Roberts

Publications

While the equivalence between online and traditional classrooms has been well-researched, very little of this includes college-level introductory Physics. Only one study explored Physics at the whole-class level rather than specific course components such as a single lab or a homework platform. In this work, we compared the failure rate, grade distribution, and withdrawal rates in an introductory undergraduate Physics course across several learning modes including traditional face-to-face instruction, synchronous video instruction, and online classes. Statistically significant differences were found for student failure rates,grade distribution, and withdrawal rates but yielded small effect sizes. Post-hoc pair-wise test was run to determine …

Recommissioning Reddi: Reviving A Doppler Asymmetric Spatial Heterodyne Spectrometer For Observing Thermospheric Winds, Robert Kallio

Doctoral Dissertations and Master's Theses

The REd-line DASH Demonstration Instrument (REDDI) was designed to prove that a Doppler Asymmetric Spatial Heterodyne (DASH) spectrometer could be used to accurately measure thermospheric winds by observing the Doppler shift of the 630nm emission of oxygen in the thermosphere. In 2015, we began a project to redesign the input optics of REDDI to repurpose the instrument from a demonstration unit to a long duration instrument. Integration of REDDI into the INSpIRe (Investigating Near-Space Interaction Regions) trailer at Embry-Riddle Aeronautical University (ERAU), Daytona Beach, began in 2016 with assembly of the new input optics in 2017. REDDI and INSpIRe will …

Low Frequency Electromagnetic Radiation From Gravitational Waves Generated By Neutron Stars, Preston Jones, Andri Gretarsson, Douglas Singleton

Publications

We investigate the possibility of observing very low frequency (VLF) electromagnetic radiation produced from the vacuum by gravitational waves. We review the calculations leading to the possibility of vacuum conversion of gravitational waves into electromagnetic waves and show how this process evades the well-known prohibition against particle production from gravitational waves. Using Newman-Penrose scalars, we estimate the luminosity of this proposed electromagnetic counterpart radiation coming from gravitational waves produced by neutron star oscillations. The detection of electromagnetic counterpart radiation would provide an indirect way of observing gravitational radiation with future spacecraft missions, especially lunar orbiting probes.

Localization Of Interacting Fields In Five-Dimensional Braneworld Models, Dewi Wulandari, Triyanta, Jusak S. Kosasih, Douglas Singleton, Preston Jones

Publications

We study localization properties of fundamental fields which are coupled to one another through the gauge mechanism both in the original Randall-Sundrum (RS) and in the modified Randall-Sundrum (MRS) braneworld models: scalar-vector, vector-vector, and spinor-vector configuration systems. For this purpose we derive conditions of localization, namely the finiteness of integrals over the extra coordinate in the action of the system considered. We also derive field equations for each of the systems and then obtain their solutions corresponding to the extra dimension by a separation of variable method for every field involved in each system. We then insert the obtained solutions …

Velocity-Dependent Inverse Cubic Force And Solar System Gravity Tests, Quentin G. Bailey, Daniel Havert

Publications

Higher mass dimension terms in an effective field theory framework for tests of spacetime symmetries are studied. Using a post-Newtonian expansion method, we derive the spacetime metric and the equations of motion for a binary system. This reveals an effective inverse cubic force correction to post-Newtonian general relativity that depends on the velocity of the bodies in the system. The results are studied in the context of laboratory and space-based tests including the effects on solar-system ephemeris, laser ranging observations, and gravimeter tests. This work reveals the coefficient combinations for mass dimension 5 operators controlling CPT violation for gravity that …

Solar Wind-Magnetosphere Coupling: A Global Perspective Of Reconnection In The Magnetotail, Miles Thomas Bengtson

Doctoral Dissertations and Master's Theses

We present a case study of the 25 December 2015 substorm which occurred between 08:15 and 08:45 Universal Time. During this interval, fast particle flows and field geometry consistent with magnetic reconnection were detected in the mid-tail region. An ejected plasmoid was observed by the lunar-orbiting Acceleration, Reconnection, Turbulence and Electrodynamics of Moon’s Interaction with the Sun (ARTEMIS) probes and corresponding dipolarization signature was observed by the Time History of Events and Macroscale Interactions During Substorms (THEMIS) spacecraft earthward of the reconnection site, which was determined to be approximately -33 RE. Ground signatures indicative of substorm activity were also observed …

Cirrus Cloud Microphysics Over Darwin, Australia, Dorothea Ivanova, Matthew Johnson

Publications

Ice clouds, crucial to the understanding of both short - and long - term climate trends, are poorly represented in global climate models (GCMs). Cirrus clouds, one of the largest uncertainties in the global radiation budget, have been inadequately studied at low latitudes. Parameterizations exist for mid - latitude and tropical cirrus ( Ivanova et al. 2001; McFarquhar et al. 1997). Due to climate sensitivity in the GCM with respect to cloud input, without robust parameterizations of cirrus clouds, the GCM is inaccurate over most output fields, including radiative forcing, temperature, albedo, and heat flux (Yao and Del Genio 1999). …

An Rbf Interpolation Blending Scheme For Effective Shock-Capturing, M. Harris, Eduardo Divo, Alain J. Kassab

Publications

In recent years significant focus has been given to the study of Radial basis functions (RBF), especially in their use on solving partial differential equations (PDE). RBF have an impressive capability of inter- polating scattered data, even when this data presents localized discontinuities. However, for infinitely smooth RBF such as the Multiquadrics, inverse Multiquadrics, and Gaussian, the shape parameter must be chosen properly to obtain accurate approximations while avoiding ill-conditioning of the interpolating matrices. The optimum shape parameter can vary significantly depending on the field, particularly in locations of steep gradients, shocks, or discontinuities. Typically, the shape parameter is chosen …

Lorentz-Symmetry Test At Planck-Scale Suppression With Nucleons In A Spin-Polarized 133 Cs Cold Atom Clock, H. Pihan-Le Bars, C. Guerlin, R.-D. Lasseri, J.-P. Ebran, Q. G. Bailey, S. Bize, E. Khan, P. Wolf

Publications

The authors introduce an improved model that links the frequency of the 133 Cs hyperfine Zeeman transitions.

A Feasibility Study For Using The Erau ÉChelle Spectrograph To Improve Orbital Parameters Of Spectroscopic Binary Systems, Stanimir Letchev

Doctoral Dissertations and Master's Theses

Binary stars are critical for establishing knowledge of stellar masses and refining the mass-luminosity relationship when used in conjunction with precise parallax measurements. However, many spectroscopic binaries have poorly defined orbital parameters as they have not been revisited with newer CCD technology since their first observations on photographic plates. This thesis examines the feasibility of using the high-resolution échelle spectrograph at Embry-Riddle Aeronautical University (ERAU) to obtain radial velocities of spectroscopic binary stars, and establishes a software pipeline to obtain their orbital parameters. This was done by looking at the double-lined binaries HD 205539 and Pegasi, as well as the …

A Coupled Localized Rbf Meshless/Drbem Formulation For Accurate Modeling Of Incompressible Fluid Flows, Leonardo Bueno, Eduardo Divo, Alain J. Kassab

Publications

Velocity-pressure coupling schemes for the solution of incompressible fluid flow problems in Computational Fluid Dynamics (CFD) rely on the formulation of Poisson-like equations through projection methods. The solution of these Poisson-like equations represent the pressure correction and the velocity correction to ensure proper satisfaction of the conservation of mass equation at each step of a time-marching scheme or at each level of an iteration process. Inaccurate solutions of these Poisson-like equations result in meaningless instantaneous or intermediate approximations that do not represent the proper time-accurate behavior of the flow. The fact that these equations must be solved to convergence at …

Leader-Follower Trajectory Generation And Tracking For Quadrotor Swarms, Michael James Campobasso

Doctoral Dissertations and Master's Theses

Swarm control is an essential step in the progress of robotic technology. The use of multiple agents to perform tasks more effectively and efficiently than a single agent allows for the expansion of robot use in all aspects of life. One of the foundations of this area of research is the concept of Leader-Follower swarm control. A crucial aspect of this idea is the generation of trajectories with respect to the leader’s path and some desired formation. With these trajectories generated, one can use a tracking controller specific to the swarm vehicle of choice to accomplish the desired swarm formation. …

Particle Production In A Gravitational Wave Background, Preston Jones, Patrick Mcdougall, Douglas Singleton

Publications

In this article, the authors study the possibility that massless particles, such as photons, are produced by a gravitational wave. That such a process should occur is implied by tree-level Feynman diagrams such as two gravitons turning into two photons, i.e., g + g → γ + γ. Here we calculate the rate at which a gravitational wave creates a massless scalar field. This is done by placing the scalar field in the background of a plane gravitational wave and calculating the 4-current of the scalar field. Even in the vacuum limit of the scalar field it has a nonzero …

Optimizing Jets For Wake Control Of Ground Vehicles, Domenic Barsotti, Sandra Boetcher

Publications

A system of wake control for a ground vehicle to help promote increased fuel efficiencies of the ground vehicle by modifying an air flow wake generated during the movement of the vehicle in a forward direction. The system includes at least one slot jet configured to be located along a rear profile portion of the ground vehicle. The at least one slot jet is configured to provide a continuous flow of air at a non-zero velocity when the ground vehicle is moving in a forward direction, the non-zero velocity being at least partially directed in a rearward direction with an …

Index Of Refraction From The Near-Ultraviolet To The Near-Infrared From A Single Crystal Microwave-Assisted Cvd Diamond, Giorgio Turri, Scott Webster, Ying Chen, Benjamin Wickham, Andrew Bennett, Michael Bass

Publications

The refractive index of a type IIa CVD-grown single-crystal diamond was measured by ellipsometry from the near ultraviolet to the near infrared region of the spectrum. As a consequence, a one term Sellmeier Equation with coefficents of B-1 = 4.658 and C-1 = 112.5 for the refractive index of diamond, for the wavelength range from 300 to 1650 nm, was derived that is only as accurate as the input data, +/- 0.002. The experimental results in this paper between 800 and 1650 nm are new, adding to the values available in the literature.

Gravity Wave And Turbulence Transport In The Mesopause Region, Yafang Guo

Doctoral Dissertations and Master's Theses

Vertical transport due to dissipating gravity waves and turbulence in the mesopause region (85-100 km) are analyzed with observational data obtained from a narrow-band sodium wind/temperature lidar located at Andes Lidar Observatory (ALO), Cerro Pach´on (30.25 S, 70.73 W), Chile. The Na lidar at ALO has been in regular operation since 2010. The upgrade of the lidar system in May 2014 resulted in great improvements of the signal levels, which enabled data acquisition of high temporal and vertical resolutions reaching 6 s and 25 m. Traditional data processing utilizes signals at lower resolutions, typically at 60 s and 500 m, …

Dynamical Processes Of Gravity Waves Propagation And Dissipation, And Statistical Characteristics Of Their Momentum Flux In The Mesosphere And Lower Thermosphere, Bing Cao

Doctoral Dissertations and Master's Theses

The mesosphere and lower thermosphere (MLT) (⇠80–110 km) is dominated by abundant atmospheric waves, of which gravity waves are one of the least understood due to large varieties in wave characteristics as well as potential sources. Gravity waves play an important role in the atmosphere by influencing the thermal balance and helping to drive the global circulation. But due to their sub-grid scale, the effects of gravity waves in General Circulation Models (GCMs) are mostly parameterized. The investigations of gravity waves in this dissertation are from two perspectives: the dynamical processes of gravity wave propagation and dissipation in the MLT …