Bulletin of the American Physical Society
87th annual meeting of the Southeastern Section of the APS
Volume 65, Number 19
Thursday–Friday, November 5–6, 2020; Virtual
Session B04: Applied Physics and Instrumentation |
Hide Abstracts |
Thursday, November 5, 2020 11:00AM - 11:12AM |
B04.00001: Ubiquitous gamma ray imaging and characterization for nuclear forensics, nuclear nonproliferation and radiological emergency response Robert Hayes Using solid state dosimetry methodologies such as electron paramagnetic resonance, thermoluminescence and optically stimulated luminescence, this work shows how all insulator materials can be used for a wide variety of detection modalities. These include retrospective gamma ray spectrometry, historical gamma ray source imaging and low level radiation detection. Proof of concept demonstrations have been made for population dosimetry in emergency response applications, nuclear nonproliferation treaty verification measurements and confirmation declaration evidence as a forensics technique. [Preview Abstract] |
Thursday, November 5, 2020 11:12AM - 11:24AM |
B04.00002: Study of Fatigue with the Field Theory of Deformation and Fracture Conor McGibboney, Sanichiro Yoshida, Naoya Fujishima, Shun Takahashi, Tomohiro Sasaki We are developing a physics-based numerical model for fatigue using the Field Theory of Deformation and Fracture. Typically, destructive testing is used to determine a specific material's fatigue properties. To examine this new theory for fatigue, we are comparing results from physical experiments with metal specimens undergoing fatigue loading against numerical simulations that describe deformation mechanics using wave dynamics. From our physical experiments we observe deformation wave dynamics, in metal specimens, using the optical interferometric technique Electronic Speckle-Pattern Interferometry (ESPI). With this approach we analyzed the temporal behavior of the displacement pattern formed while the specimen was experiencing cyclic loads. From the viewpoint of traditional Fatigue Analysis of aircraft wings, cracks are formed due to cyclic loading, and these cracks propagate through a structure. Failures occur when stresses on these cracks are above a material's ultimate strength. In our numerical simulations we qualitatively observe the same type of wave dynamics seen in our fatigue loading experiments. This work is of importance for aerospace engineers as it could be used to reduce costs associated with destructive testing. [Preview Abstract] |
Thursday, November 5, 2020 11:24AM - 11:36AM |
B04.00003: Metal Artifact Reduction using virtual monochromatic imaging with dual-energy CT Alan Li Diagnostic CT scanners use polychromatic x-ray beams. The presence of materials with a high atomic number causes metal artifacts. Virtual monochromatic images(VMIs) generated from dual-energy CT(DECT) reduce such artifacts. X-ray attenuation coefficients can be represented as a linear combination of a Compton scatter and a photoelectric component, which can be modeled using two basis materials at a given energy. For DECT, high and low energy images can be represented similarly to get two linear equations for each voxel, then by solving which, one can obtain the density maps for two basis materials and calculate monochromatic images. DECT images for a head phantom with a large metal bead were collected, and VMIs were generated. Then metal artifacts were evaluated with Metal artifact index(MAI) and qualitatively. For VMI with energy$\ge $100keV, metal artifacts were noticeably reduced visually. A maximum drop by a factor of 5 was observed in MAI at 150keV compared to original images. However, the contrast to noise ratio decreased across the VMI as the energy increased. VMI technique was implemented using DECT images and was shown to be effective in reducing metal artifacts in a head phantom. [Preview Abstract] |
Thursday, November 5, 2020 11:36AM - 11:48AM |
B04.00004: Position-Sensitive Response of Single-Pixel Large-Area SNSPDs Brian Lerner Superconducting nanowire single photon detectors (SNSPDs) are typically employed as single-pixel small-area detectors. Demand for large-area detectors is building for a variety of applications including microscopy and free-space quantum communication. Using large-area SNSPDs, we examine the leading edge of the readout pulse as a function of incident spot size, bias current, and mean photon number per pulse. We show a bimodal distribution of rise times that is correlated with spot size for small photon number. In the limit of low bias current, the set of dark-count readout pulses are most similar to the bright-count pulses at large spot size and small photon number. These observations are consistent with a model of traveling microwave modes excited by single photons incident at different positions along the length of the nanowire. [Preview Abstract] |
Thursday, November 5, 2020 11:48AM - 12:00PM |
B04.00005: Three-Dimensional Spatialization in Two-Channel Stereo Sound Milind Kunchur Among the variety of audio configurations in use—from basic monophonic to complex multi-channel surround-sound systems—two-channel stereophonic (stereo) systems have dominated sound reproduction for the purpose of music. Unbeknownst to most of the consumer public, stereo systems in the high end of audio performance can approach the illusion of a live performance, with realistic instrumental timbres and 3D spatialization. Among the three dimensions of the recreated soundstage, the portrayal of elevation remains controversial. In this work, an audio system was assembled that had sufficient fidelity to achieve 3D spatialization, and it was proven through psychoacoustic testing that elevation differentiation of instrumental images can indeed be perceived. The relationship between auditory mechanisms involved in natural-sound localization and stereo-sound imaging is discussed. [Preview Abstract] |
Thursday, November 5, 2020 12:00PM - 12:12PM |
B04.00006: Interpreting Myoelectric Signals via Machine Learning Algorithms Marigordon Varner, Preston Robinette, Eli Owens Advancements in the field of medical prosthetics have created a gap in the quality to cost ratio when using these advanced medical solutions. Similarly, low-cost options, such 3D printed prosthetics, often sacrifice much of the natural mobility of a more expensive prosthetic. Our goal is to develop upper prosthetics that are both low-cost and highly functional. Starting with an open source 3D printed hand, we fit this hand with electronics of our own design to measure and interpret the myoelectric signals generated by the user. These myoelectric signals are used to control the prosthetic giving the user intuitive operation. Before the signals can be interpreted, they are first cleaned by removing the observed flicker noise that was dominating the recorded signals. After cleaning the signals, we tested several machine learning algorithms using signal features such as maximum and minimum voltage and the dominant frequency component of the myoelectric signal. We found that the decision tree algorithm had the highest predictive power, correctly identifying the gesture over 75% of the time. Through this work, we move towards the creation of a low-cost but high functioning prosthetic that will enable many amputees to live a life of confidence and mobility. [Preview Abstract] |
Thursday, November 5, 2020 12:12PM - 12:24PM |
B04.00007: Experimental and Numerical Studies of the Mechanical Damped Driven Duffing Oscillator Lars Hebenstiel, Doug Harper, Ivan Novikov The Duffing Oscillator (DO) is a bistable, nonlinear oscillator derived from a double well potential which exhibits various phenomena such resonance and stochastic resonance (SR). SR occurs when a system experiences resonance due to some amount of noise being added to the system, with some optimal amount of noise for the most resonance. These phenomena have been observed in ring lasers, electron paramagnetic resonance and various other models. In this talk, we present the experimental results obtained with a magnetically driven mechanical model of the DO recently proposed. The system consists of high-power magnet attached to a spring and placed inside a solenoid. The potential energy of this system is described through use of binomial expansion as a fourth order potential. The current through the second coil placed underneath the experimental setup is varied to provide external periodic and white noise forces. The oscillator's position is measured with a force probe, and with a grayscale transparency, photo-resistor/LED system which measures the intensity of light passing through the semitransparent sheet. LabVIEW control systems are used to vary the current through the coils and acquire data from the position sensors. [Preview Abstract] |
Follow Us |
Engage
Become an APS Member |
My APS
Renew Membership |
Information for |
About APSThe American Physical Society (APS) is a non-profit membership organization working to advance the knowledge of physics. |
© 2024 American Physical Society
| All rights reserved | Terms of Use
| Contact Us
Headquarters
1 Physics Ellipse, College Park, MD 20740-3844
(301) 209-3200
Editorial Office
100 Motor Pkwy, Suite 110, Hauppauge, NY 11788
(631) 591-4000
Office of Public Affairs
529 14th St NW, Suite 1050, Washington, D.C. 20045-2001
(202) 662-8700