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Full-Text Articles in Physical Sciences and Mathematics

Controlling The Chaotic Motions Of An Airfoil With A Nonlinear Stiffness Using Closed-Loop Harmonic Parametric Excitation, Robert Bruce Alstrom Dec 2020

Controlling The Chaotic Motions Of An Airfoil With A Nonlinear Stiffness Using Closed-Loop Harmonic Parametric Excitation, Robert Bruce Alstrom

Faculty and Student Publications

The purpose of this research is to conduct a preliminary investigation into the possibility of suppressing the flutter and post-flutter (chaotic) responses of a two-dimensional self-excited airfoil with a cubic nonlinear stiffness (in torsion) and linear viscous damping via closed-loop harmonic parametric excitation. It was found that the initial configuration of the proposed control scheme caused the torsional/pitch dynamics to act as a nonlinear energy sink; as a result, it was identified that the mechanisms of vibration suppression are the resonance capture cascade and the short duration or isolated resonance capture. It is the isolated resonance capture that is responsible …


New Method For Beyond The Standard Model Invisible Particle Searches In Tau Lepton Decays, E. De La Cruz-Burelo, A. De Yta-Hernandez, M. Hernandez-Villanueva Dec 2020

New Method For Beyond The Standard Model Invisible Particle Searches In Tau Lepton Decays, E. De La Cruz-Burelo, A. De Yta-Hernandez, M. Hernandez-Villanueva

Faculty and Student Publications

Motivated by models proposed to explain Standard Model anomalies, and the unprecedented τ+τ- data to be collected by the Belle II experiment during the next years, we study the kinematics of tau pair decays and propose a new method to search for lepton flavor violating processes in tau lepton decays to invisible beyond Standard Model particles, such as τ→ℓα, where ℓ is either an electron or a muon, and α is a massive particle that escapes undetected. The new method improves by one order of magnitude the expected upper limit on the τ→ℓα production in 3×1 prong tau decays and …


Reliable Extraction Of Energy Landscape Properties From Critical Force Distributions, Sudeep Adhikari, K. S. D. Beach Jun 2020

Reliable Extraction Of Energy Landscape Properties From Critical Force Distributions, Sudeep Adhikari, K. S. D. Beach

Faculty and Student Publications

The structural dynamics of a biopolymer is governed by a process of diffusion through its conformational energy landscape. In pulling experiments using optical tweezers, features of the energy landscape can be extracted from the probability distribution of the critical force at which the polymer unfolds. The analysis is often based on rate equations having Bell-Evans form, although it is understood that this modeling is inadequate and leads to unreliable landscape parameters in many common situations. Dudko et al. [Phys. Rev. Lett. 96, 108101 (2006)PRLTAO0031-900710.1103/PhysRevLett.96.108101] have emphasized this critique and proposed an alternative form that includes an additional shape parameter (and …