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Full-Text Articles in Physics
Molecular Dynamics Model Of Carbon Nanotubes In Epon 862/Detda Polymer, Guttormur Arnar Ingvason
Molecular Dynamics Model Of Carbon Nanotubes In Epon 862/Detda Polymer, Guttormur Arnar Ingvason
Doctoral Dissertations and Master's Theses
The aerospace industry is interested in increasing the strength while reducing the weight of carbon fiber composite materials. Adding single walled carbon nanotubes (SWCNT) to a polymer matrix can achieve that goal by improving delamination properties of the composite. Due to the complexity of polymer molecules and the curing process, few 3-D Molecular Dynamics simulations of a polymer-SWCNT composite have been run. Our model runs on the Large-scale Atomic/Molecular Massively Parallel Simulator (LAMMPS), with a COMPASS (Condensed phase Optimized Molecular Potential for Atomistic Simulations Studies) potential to represent the interactions between the atoms of the polymer and the SWCNT. This …
Numerical Analysis And Theory Of Oblique Alfvenic Solitons Observed In The Interplanetary Magnetic Field, Harry Raphael Wheeler Iv
Numerical Analysis And Theory Of Oblique Alfvenic Solitons Observed In The Interplanetary Magnetic Field, Harry Raphael Wheeler Iv
Doctoral Dissertations and Master's Theses
Recently, there have been reports of small magnetic pulses or bumps in the interplanetary magnetic field observed by various spacecraft. Most of these reports claim that these localized pulses or bumps are solitons. Solitons are weakly nonlinear localized waves that tend to retain their form as they propagate and can be observed in various media which exhibit nonlinear steepening and dispersive effects. This thesis expands the claim that these pulses or bumps are nonlinear oblique Alfven waves with soliton components, through the application of analytical techniques used in the inverse scattering transform in a numerical context and numerical integration of …
Controllability Of Open Quantum Optical Systems: Photon Fock States In A Cavity, Byron Henry Lowry
Controllability Of Open Quantum Optical Systems: Photon Fock States In A Cavity, Byron Henry Lowry
Doctoral Dissertations and Master's Theses
There has always been a signicant interest in using optical systems to control quantum phenomena. A major barrier to controllability of quantum optical systems is the fact that the systems are usually innite dimensional open systems, two cases which have mostly negative controllability results. This thesis develops three new denitions of controllability and reformulates a previous controllability theorem in order to apply the theorem to the system of interest. Then, the controllability of a pumped dissipative quantum optical cavity with engineered decoherence is investigated using previously developed concepts in quantum control theory, as well as the ones developed in this …
A 3-D Model Of The Auroral Ionosphere, Yishi Lee
A 3-D Model Of The Auroral Ionosphere, Yishi Lee
Doctoral Dissertations and Master's Theses
A new 3-D model of the high latitude ionosphere is developed to study the coupling of the ionosphere with the magnetosphere and neutral atmosphere. The model consists of equations describing conservations of mass, momentum and energy for the six ionospheric constituents (O+, NO+, N+2 , O+2 , N+ and e-) and an electrostatic potential equation. This 3-D model is used to examine interrelated processes of ion heating, plasma structuring due to perpendicular transport, ion upflow, molecular ion generation, and neutral wave forcing. It is first validated by comparisons with a 2-D model, which uses similar mathematical and numerical approaches, and …
Nonlinear Control For Dual Quaternion Systems, William D. Price
Nonlinear Control For Dual Quaternion Systems, William D. Price
Doctoral Dissertations and Master's Theses
The motion of rigid bodies includes three degrees of freedom (DOF) for rotation, generally referred to as roll, pitch and yaw, and 3 DOF for translation, generally described as motion along the x, y and z axis, for a total of 6 DOF. Many complex mechanical systems exhibit this type of motion, with constraints, such as complex humanoid robotic systems, multiple ground vehicles, unmanned aerial vehicles (UAVs), multiple spacecraft vehicles, and even quantum mechanical systems. These motions historically have been analyzed independently, with separate control algorithms being developed for rotation and translation. The goal of this research is to study …
Robust Control Methods For Nonlinear Systems With Uncertain Dynamics And Unknown Control Direction, Chau T. Ton
Robust Control Methods For Nonlinear Systems With Uncertain Dynamics And Unknown Control Direction, Chau T. Ton
Doctoral Dissertations and Master's Theses
Robust nonlinear control design strategies using sliding mode control (SMC) and integral SMC (ISMC) are developed, which are capable of achieving reliable and accurate tracking control for systems containing dynamic uncertainty, unmodeled disturbances, and actuator anomalies that result in an unknown and time-varying control direction. In order to ease readability of this dissertation, detailed explanations of the relevant mathematical tools is provided, including stability denitions, Lyapunov-based stability analysis methods, SMC and ISMC fundamentals, and other basic nonlinear control tools. The contributions of the dissertation are three novel control algorithms for three different classes of nonlinear systems: single-input multipleoutput (SIMO) systems, …