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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 …
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, …
Payload Charging Events In The Mesosphere And Their Impact On Langmuir Type Electric Probes, T. A. Bekkeng, Aroh Barjatya, U. P. Hoppe, M. Friedrich
Payload Charging Events In The Mesosphere And Their Impact On Langmuir Type Electric Probes, T. A. Bekkeng, Aroh Barjatya, U. P. Hoppe, M. Friedrich
Publications
Three sounding rockets were launched from Andøya Rocket Range in the ECOMA campaign in December 2010. The aim was to study the evolution of meteoric smoke particles during a major meteor shower. Of the various instruments onboard the rocket payload, this paper presents the data from a multi-Needle Langmuir Probe (m-NLP) and a charged dust detector. The payload floating potential, as observed using the m-NLP instrument, shows charging events on two of the three flights. These charging events cannot be explained using a simple charging model, and have implications towards the use of fixed bias Langmuir probes on sounding rockets …
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 …