Detectability of f-mode Unstable Neutron Stars by the Schenberg Spherical Antenna

The Brazilian spherical antenna (Schenberg) is planned to detect high frequency gravitational waves (GWs) ranging from 3.0 kHz to 3.4 kHz. There is a host of astrophysical sources capable of being detected by the Brazilian antenna, namely: core collapse in supernova events; (proto)neutron stars undergoing hydrodynamical instability; f-mode unstable neutron stars, caused by quakes and oscillations; excitation of the first quadrupole normal mode of 4-9 solar mass black holes; coalescence of neutron stars and/or black holes; exotic sources such as bosonic or strange matter stars rotating at 1.6 kHz; and inspiralling of mini black hole binaries. We here address our study in particular to the neutron stars, which could well become f-mode unstable producing therefore GWs. We estimate, for this particular source of GWs, the event rates that in principle can be detected by Schenberg and by the Dutch Mini-Grail antenna.Comment: 7 pages, 3 figures; Classical and Quantum Gravity (in press

A Uniform Approximation for the Coherent State Propagator using a Conjugate Application of the Bargmann Representation

We propose a conjugate application of the Bargmann representation of quantum mechanics. Applying the Maslov method to the semiclassical connection formula between the two representations, we derive a uniform semiclassical approximation for the coherent state propagator which is finite at phase space caustics.Comment: 4 pages, 1 figur

Rutherford scattering with radiation damping

We study the effect of radiation damping on the classical scattering of charged particles. Using a perturbation method based on the Runge-Lenz vector, we calculate radiative corrections to the Rutherford cross section, and the corresponding energy and angular momentum losses.Comment: Latex, 11 pages, 4 eps figure

Development of a Safety Performance Decision-Making Tool for Flight Training Organization

Title 14 of the Code of Federal Regulations (CFR) Part 141 flight training organizations are actively pursuing ways to increase operational safety by introducing advanced risk assessment and decision-making techniques. The purpose of the dissertation was to create and validate a safety performance decision-making tool to transform a reactive safety model into a predictive, safety performance decision-making tool, specific to large, collegiate Title 14 CFR Part 141 flight training organizations, to increase safety and aid in operational decision-making. The validated safety decision-making tool uses what-if scenarios to assess how changes to the controllable input variables impact the overall level of operational risk within an organization’s flight department. Utilizing SPIs determined to be most indicative of flight risk within large, collegiate flight training organizations, a predictive, safety performance decision-making tool was developed utilizing Monte Carlo simulation. In a high-risk system beset with uncertainty, applying Monte Carlo simulation addresses the need to accommodate uncontrollable inputs into the model in a manner that enables the model to produce meaningful output data. This research utilizes the validated equations drawn from the non-statistical model developed by Anderson, Aguiar, Truong, Friend, Williams, & Dickson (2020) for the mathematical inputs driving the computational nodes, including the SPIs, as the foundation to develop the safety performance decision-making tool. The probability distributions of the uncontrollable inputs were drawn from a sample of operational data from September 2017 to September 2019 from a large, collegiate 14 CFR Part 141 flight training organization in the southeastern United States. The study conducted simulation runs based on true operational ranges to simulate the operating conditions possible within large, collegiate CFR Part 141 flight training organizations with varying levels of controllable resources including personnel (Aviation Maintenance Technicians and Instructor Pilots) and expenditures (active flight students and available aircraft). The study compared the output from three different Verification Scenarios—each using a unique seed value to ensure a different sample of random numbers for the uncontrollable inputs. ANOVA testing indicated no significant differences appeared among the three different groups, indicating the results are statistically reliable. Four What-if Scenarios were conducted by manipulating the controllable inputs. Mean probability was the key output and represents the forecasted level of operational risk on a standardized 0-5 risk scale for the Flight Score, Maintenance Score, Damage and Related Impact, and an Overall Risk Score. Results indicate the lowest Overall Risk Score occurred when the level of personnel was high yet expenditures were moderate. Changes to the controllable inputs are reflected by variations to the outputs demonstrating the utility and potential for the safety performance decision-making tool. The outputs could be utilized by safety personnel and administrators to make more informed safety-related decisions without expending unnecessary resources. The model could be adapted for use in any CFR Part 141 flight training organization with data collection capabilities and an SMS by modifying the input value probability distributions to reflect the operating conditions of the selected 14 CFR Part 141 flight training organization

Semiclassical Tunneling of Wavepackets with Real Trajectories

Semiclassical approximations for tunneling processes usually involve complex trajectories or complex times. In this paper we use a previously derived approximation involving only real trajectories propagating in real time to describe the scattering of a Gaussian wavepacket by a finite square potential barrier. We show that the approximation describes both tunneling and interferences very accurately in the limit of small Plank's constant. We use these results to estimate the tunneling time of the wavepacket and find that, for high energies, the barrier slows down the wavepacket but that it speeds it up at energies comparable to the barrier height.Comment: 23 pages, 7 figures Revised text and figure

Distinct magnetic signatures of fractional vortex configurations in multiband superconductors

Vortices carrying fractions of a flux quantum are predicted to exist in multiband superconductors, where vortex core can split between multiple band-specific components of the superconducting condensate. Using the two-component Ginzburg-Landau model, we examine such vortex configurations in a two-band superconducting slab in parallel magnetic field. The fractional vortices appear due to the band-selective vortex penetration caused by different thresholds for vortex entry within each band-condensate, and stabilize near the edges of the sample. We show that the resulting fractional vortex configurations leave distinct fingerprints in the static measurements of the magnetization, as well as in ac dynamic measurements of the magnetic susceptibility, both of which can be readily used for the detection of these fascinating vortex states in several existing multiband superconductors.Comment: 5 pages, 4 figure

Analysis of structure withdissipator spectra under design and control

Las estructuras de Quito, Ecuador, son diseñadas para el espectro de la norma ecuatoriana de 2015, o para el hallado en la microzonificación de la ciudad de 2012. Estos espectros consideran en forma macro las fallas ciegas inversas sobre las que se halla la ciudad. En este artículo se destaca la importancia de verificar el diseño para los espectros de control que fueron desarrollados mediante métodos determinísticos para Quito en el 2015, los mismos que consideran la generación de sismos en las fallas ciegas. En el artículo se presentan dos modelos de plasticidad extendida para los elementos estructurales y un modelo de plasticidad para los disipadores ADAS o TADAS. Luego se indica con cierto detalle la técnica del pushover multimodal y el método del espectro de capacidad con el cual se halla el punto de capacidad de una estructura que fue inicialmente calculada para los espectros de diseño. Dicha estructura ha sido reforzada con disipadores ADAS para que no colapse ante el espectro de control que tiene ordenadas más altas que el espectro de diseño.The structures of Quito, Ecuador, are designed for the spectrum of the Ecuadorian code of 2015, or using the study of microzoning of the city of 2012. These spectra consider in general the effect of the blind reverse faults belonging to the city area. In this article, it is pointed out the importance of checking the design for the deterministic control spectra developed for Quito in 2015 based on earthquakes simulated in the blinds faults. In this paper we considered two models of extended plasticity for the structural elements and one model of plasticity for the ADAS and TADAS devices. Then, the technique of multimodal pushover is described, as well as the method of the capacity spectrum used to calculate the performance point of the structure. This structure was initially calculated by using design spectra and it had to be reinforced with ADAS devices in order to avoid its collapse for the control spectrum which has higher ordinates than the design one.Peer Reviewe