Bulletin of the American Physical Society
APS March Meeting 2018
Volume 63, Number 1
Monday–Friday, March 5–9, 2018; Los Angeles, California
Session E06: Undergraduate Research IVUndergraduate
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Sponsoring Units: APS SPS Chair: Matthew Wright, Adelphi University Room: LACC 153A |
Tuesday, March 6, 2018 8:00AM - 8:12AM |
E06.00001: Global Helical Modes in Low-Density Jets David D.W. Ren, Larry K. B. Li It is well known that low-density jets can exhibit global instability in the form of self-excited axisymmetric oscillations. It is less well known, however, that such jets can also exhibit global instability in the form of self-excited helical oscillations. The existence of such helical modes has been predicted before in the local linear spatiotemporal stability analysis of Coenen, Sevilla, and S\'anchez \cite{Coenen_Sevilla_S\'anchez2008} for long circular injectors with thick shear layers, but they have yet to be found in experiments. We report experimental evidence that low-density jets can exhibit global helical modes. We characterize the dynamics of the jet with time-resolved Schlieren imaging and quantify the departure from axisymmetry with the phase angle between diametrically opposite shear layers. On decreasing the non-dimensional injector length $L_t^{-1}=(Re_j a)/l_t$ (where $Re_j$ is the jet Reynolds number, $a$ is the jet radius, and $l_t$ is the injector length), we find that the global instability switches from an axisymmetric mode to a helical mode, with the latter being weaker than the former. This shows that it is possible to create self-excited helical modes in laboratory low-density jets, provided that the shear layer at the nozzle exit is sufficiently thick. |
Tuesday, March 6, 2018 8:12AM - 8:24AM |
E06.00002: Comparison of cavitation in two liquids through sudden acceleration Matthew Karnes, Heidrun Schmitzer When forced to suddenly accelerate, liquids have a tendency to undergo cavitation, which can prove to be catastrophic for the liquid’s container. Whether this cavitation will occur or not can be determined using a formula which takes into account the acceleration of the container as well as the vapor pressure of the liquid, density, and fill height. In this project we investigate the dependence of cavitation on the viscosity of the liquid. To do this, the cavitation that is produced in deionized water and fructose corn syrup is compared. A free falling weight which strikes the container is used to induce cavitation by sudden acceleration. A high speed camera records the created void(s) in the container. From these recordings the size and number of the bubbles induced in the two liquids are compared. We then attempt to find the relationship between the viscosity and cavitation. |
Tuesday, March 6, 2018 8:24AM - 8:36AM |
E06.00003: Star-Shaped Oscillation of Water Drops under Vertical Periodic Excitation. Qian Xu This paper investigates the star-shaped oscillation of liquid drops under vertical excitation theoretically and experimentally. When simply put on a solid surface, a liquid drop approximately adopts the shape of a spherical cap. However, when the drop is subjected to a vertical periodic excitation the drop’s initial axial symmetry is broken and star-shaped oscillation occurs. In the first part, two numbers determining the azimuthal and radial wave modes are found and dispersion relation is derived. A parametric resonance model is proposed to derive the correlation between the excitation frequency and corresponding standing wave patterns. In the second part, we show that the air cushion under the drop due to Leidenfrost effect exert a periodical force on the drop and thus the phenomenon of "Leidenfrost star" can be explained. Experiments are in good agreement with theory. |
Tuesday, March 6, 2018 8:36AM - 8:48AM |
E06.00004: Using Fast Enumeration to Re-Discover The Navier-Stokes Equations from Lattice Boltzmann Simulation Chao Ju, Mark Stalzer Theoretically, laws of statistical mechanics imply laws of hydrodynamics. The Lattice Boltzmann Method (LBM), an algorithm built on the principles of statistical mechanics, provides an alternative way to simulate fluid flow. This paper shows that using LBM simulation of 2D low Reynolds number flow past a cylinder, the machine is able to re-discover the Navier-Stokes equations for incompressible flow within 2 seconds. This is done by TheoSea, a Julia program that uses fast enumeration and singular value decomposition to re-discover smooth, differential theories from data. |
Tuesday, March 6, 2018 8:48AM - 9:00AM |
E06.00005: Dynamics and chaotic properties of a spatially extended oil-candle array Hannah Phillips, Conner Herndon, Flavio Fenton Extensive research has been devoted to the discovery of simple media that display chaotic properties. One such simple system is a candle wick that draws flammable oil from a reservoir. By varying oil viscosity and wick material, the system exhibits refractoriness and nonlinear restitution dynamics under constant periodic re-ignition. When arranged in a grid these candles can ignite their neighbors, creating propagating fire waves that can display complex spatial dynamics. In this talk, I will discuss our experimental results of the oil-candle system in multiple geometries. Furthermore, I will discuss a simple return map we have derived based on these experimental data, from which we characterize families of system parameters associated with dynamical phenomena such as period-doubling and chaos. |
Tuesday, March 6, 2018 9:00AM - 9:12AM |
E06.00006: Rolling Polygons with Granular Material down an Incline Sidney Eckert, Joseph West The dynamics of granular material is an ambiguous topic but continues to be an active area of research. Physicists and other professionals have tried to explain the phenomena through various theoretical models and corresponding laboratory experiments. In this investigation, hollow regular polygons were filled to various degrees of granular media and rolled down a ramp. The dynamics of a terminal velocity and at lower angles a reproducible stopping motion were observed. A potential theory was developed to describe velocity and energy of motion. Trends were apparent in angle versus distance, granules position versus polygon position, and percent fill versus average velocity. |
Tuesday, March 6, 2018 9:12AM - 9:24AM |
E06.00007: Parameters That Effect Brine Shrimp Pattern Selection Zoha Naqawe, Andrea Welsh, Flavio Fenton Self-propelled particles are physically rich systems that are also relevant in biology such as microorganisms, schools of fish, flocks of birds, and even human crowds. This poster will cover the preliminary experimental work of the collective motion of Artemia franscicana otherwise known as brine shrimp. Large collections of these shrimp will aggregate in such a way that they will form spatial patterns, which depend on environmental properties that play into the driving and dissipation of the system. Also, the natural phototaxis of shrimp, especially 1st instar stage shrimp, effect pattern selection. We look a bit at the individual properties such as shrimp speed and how that is affected by age i.e. size. These differences can cause a phase separation to occur where shrimp separate into slower and faster swarms and causes spatial patterns in three dimensions. |
Tuesday, March 6, 2018 9:24AM - 9:36AM |
E06.00008: Using subsetting to identify factors significantly associated with breast cancer recurrence within patient populations based on MRI usage Irene Helenowski, Seema Khan Controversies remain as to how beneficial MRI (magnetic resonance imaging) can influence the association of recurrence with demographic and clinical factors of the patient population. Here, we examine this preposition by analyzing cross-tabulations of breast cancer recurrences within 586 patient documented as having had an MRI scan and within 500 patients documented with no prior MRI use from the Lynn Sage Cancer Research Foundation. Results indicate that MRI use appeared to be associated with lower recurrence rates among ER/PR positive patients in contrast to their ER/PR negative counterparts (5.34% versus 20.51%, p < 0.0001 in the MRI subset; 11.41% vs. 18.60% with no MRI) and with a lessened detrimental effect of palpable mass on recurrence (12.14% versus 6.32%, p = 0.02 in the MRI subset; 21.49% versus 9.7%, p = 0.001 with no MRI) but also with the lessened beneficial effect of optimal therapy (8.27% versus 11.11%, p = 0.66 in the MRI subset; 11.80% versus 23.53%, p = 0.06 with no MRI). MRI use did not appear to affect the association between recurrence and age, race, or histology. These outcomes lead us to recommend more investigation into how this technology influences breast cancer recurrence rates to determine which patient populations could benefit most from its use. |
Tuesday, March 6, 2018 9:36AM - 9:48AM |
E06.00009: Experimental and computational modeling of cardiac electrical propagation in bio-engineered sinoatrial node tissue. Anthony Aportela, Conner Herndon, Sandra Gonzalez, Hee Cho The sinoatrial node (SAN) is a collection of auto-oscillatory cells in the heart that constitutes the pacemaker, sending rhythmic electrical stimulation to the myocardium to initiate contraction. Current arrhythmic or dysfunctional SAN treatments include ablation, pharmacological therapies, and implanted electronic pacing devices. Pediatric patients with congenital heart defects, treatment requires repeated procedures over the course of a lifetime. A proposed solution is bioengineered pacemaker cells that replicate healthy SAN behavior and control the heart’s rhythm. To manufacture a successful bioengineered pacemaker, it is critical we understand the electrical connection between the SAN and the surrounding tissue. In monolayer cultures of induced pacemaker cells, fluorescence signals of intracellular calcium concentrations show the action potential propagation on the cellular level. In this talk, I will discuss a minimal ionic cell model we constructed to replicate the observed SAN dynamics. Model parameters were estimated from experimental data using a genetic algorithm. The model was then coupled in complicated tissue geometries that resemble the SAN. furthermore, this model was implemented in full atrial simulations to determine the optimal geometries for robust pacemaking. |
Tuesday, March 6, 2018 9:48AM - 10:00AM |
E06.00010: Oleocanthal's Interaction with Amino Acids Tyler Jenkins, Guoping Zhang There is evidence to suggest that oleocanthal, a |
Tuesday, March 6, 2018 10:00AM - 10:12AM |
E06.00011: Characterizing the Aggregation Pathway of Mutated Tau Protein Anthony Cooper, Luca Larini The aggregation of tau protein is a hallmark of Alzheimer’s disease, chronic traumatic encephalopathy typical of athletes and is associated with multiple forms of dementia. There is no cure for Alzheimer’s disease and early stage diagnosis is still impossible but recent studies have begun to investigate tau’s aggregation pathways. Aggregation of tau can be triggered by oxidative stress, crowding effects, mutations and posttranslational modifications. Since tau is an intrinsically disordered protein it is difficult to study these changes using experimental techniques such as NMR and X-ray diffraction. Thus, in this project, we use molecular dynamics simulations to characterize the conditions under which tau aggregation is triggered. We will discuss the latest findings on the effects of point mutations and ionizing radiation on the aggregation pathway of tau. |
Tuesday, March 6, 2018 10:12AM - 10:24AM |
E06.00012: The Characterization of Embiopteran Silk and Its Interactions with Water Evangelea DiCicco, Grace Stokes, Janice Edgerly, Richard Barber Embioptera (webspinners) are insects that produce silk in glands housed in their forelegs (basitarsomeres). Embioptera use this silk for shelter and protection from predators. Their silk is the finest of all known animal silks, with fibers on the order of 0.05-0.1 μm in diameter. In comparison, spider and silkworm silks have diameters of roughly 1-4 μm and 5-10 μm respectively. Through the use of scanning electron microscopy (SEM), we quantified the silk diameters of multiple species of embioptera and discovered unique silk structures that these insects produce. In the field, water appears to interact differently with silk from different species. We have studied how water droplets change the structure, morphology, and chemistry of the silk at the macroscopic scale through contact angle and tilt angle measurements and at the nano scale using SEM. These studies have allowed us to better understand the characteristics of Embioptera silk. |
Tuesday, March 6, 2018 10:24AM - 10:36AM |
E06.00013: Why Students need to know about the History of Physics Victoria Eng History and physics may seem like they are on opposite sides of the academic spectrum but their relationship is crucial for the continued development of the physical sciences field. This relationship is often overlooked by the people who need it the most, physics undergraduate students. The history of physics is often only addressed as small antidotes in complex and overwhelming physics classes, like Modern Physics. These antidotes are easily overlooked but that information can shape the future of physics, science, and even the world. This project not only provides a synthesis of each of the six reasons why the history of physics is important, but it also examines how to provide this information to physics undergraduate students in a meaningful way. Throughout the duration of this project, I grappled with the issue of accessibility by using a variety of platforms to appeal to a large audience with different learning styles. These platforms include: a physical exhibit, a comprehensive website, short videos, newsletters, and articles. |
Tuesday, March 6, 2018 10:36AM - 10:48AM |
E06.00014: You Have More Options Than You Think: Applying Your Physics Degree Mary Ann Mort As an intern for the American Physical Society Careers Program through the Society of Physics Students Internship Program, I worked on a series of projects to promote the diverse career options that physics majors have. “Physicist” historically implies a research professor at a university, yet only about 5% of all physics bachelor's will end up with that profession. In order for undergraduate physics majors to better understand how they can utilize their physics skill set outside of academia, I interviewed and synthesized profiles of young physics entrepreneurs in order to promote physics innovation and entrepreneurship (PIE), an APS initiative. These “Startup Stories” are featured on the APS website and have led to published articles in both The Vector and APS News. Another project inspired by a push for physics majors to continue their education influenced the development of a flowchart infographic - “Should I Go to Grad School?” - to allow undergraduates to decide if a graduate degree is right for them. I will also highlight the most important thing I learned this summer - networking. |
Tuesday, March 6, 2018 10:48AM - 11:00AM |
E06.00015: Policy-ing the Science: The Importance of Science Policy Communication Platforms Lisa McDonald, Mitch Ambrose, Alexis Wolfe Science policy encompasses a wide range of topics, from debates about how much to fund different disciplines of science to how policymakers use (or ignore) scientific advice. As an intern for the American Institute of Physics’s science policy news service—FYI—I covered a variety of science policy events in and around the D.C. area, including Congressional hearings, National Academies studies, and a science coalition meeting. In my presentation, I will give a brief history of the FYI publication and how it fills a vital role in providing up-to-date coverage on science policy discussions and legislation in our government. From there I will discuss the articles I had a personal hand in producing during my time here this summer and the big takeaways I will carry with me as I move forward into my future career. |
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