Center for Soft Matter and Biological Physics Friday Discussion Meetings

Summer 2018

Organizer: Vinh Nguyen

These meetings occur on Fridays from 1:30pm to 2:30pm in Robeson 304 (unless otherwise indicated)

May 2018
May 25

Friday 1:30pm
304 Robeson Hall
(poster)


Organizer: Vinh Nguyen

June 2018
June 1

Friday 1:30pm
304 Robeson Hall
(poster)

Organizer: Vinh Nguyen

June 8

Friday 1:30pm
304 Robeson Hall
(poster)


Organizer: Vinh Nguyen

June 15

Friday 1:30pm
304 Robeson Hall
(poster)


Organizer: Vinh Nguyen

June 22

Friday 1:30pm
304 Robeson Hall
(poster)

Ruslan Mukhamadiarov (Physics, Virginia Tech)

"Transverse Temperature Interface in Katz-Lebowitz-Spohn Model"

Driven lattice gas with attractive nearest neighbor interactions and periodic boundaries demonstrate intriguing dynamics, when parts of lattice held at different temperatures. In two dimensions, this complex system experiences a jamming transition in the high temperature zone, and forms stripes in the low temperature regions. Density profiles are strikingly similar with those for Asymmetric Exclusion Process (ASEP) with open boundary conditions when injection and ejection rates are equal. In this talk, I will discuss the dynamics of two-temperature driven lattice gas system and characterize its density profile using analytical results and Monte Carlo simulations.


Organizer: Vinh Nguyen

June 29

Friday 1:30pm
304 Robeson Hall
(poster)

Prof. Uwe Tauber (Virginia Tech, Physics)

"Interactive Discussion: Manuscript writing"


Organizer: Vinh Nguyen

July 2018
July 6

Friday 1:30pm
304 Robeson Hall
(poster)

Shadi Esmaeili

"An Exploration of Characteristics of System of Kuramoto Oscillators"

Coupled oscillators and emergent synchronized patterns can be found in many phenomena in nature. Kuramoto model is the simplest model of coupled oscillators with an exact solution that can explain many such phenomena. By choosing a proper coupling constant and topology the system shows multi-stability. Also, by choosing non-homogeneous frequencies long period orbits emerge in the system. We study the effects of the change in different parameters of the system (e.g. coupling constant and width of frequency distribution) as well as the response of the system to external noise.


Organizer: Vinh Nguyen

July 13

Friday 1:30pm
304 Robeson Hall
(poster)

Ahmadreza Azizi (Physics, Virginia Tech)

"Microscopic description of Generalized Voter Model"

The Langevin equation of critical phenomena in the presence of two symmetric absorbing states is considered as a novel macroscopic description of generalized Voter model (GVM). Numerical integration of GVM in two dimensions shows that the direct transition from a disorder phase to either of the absorbing states is described by voter critical point. Also, indirect transitions to the ordered state can happen where the Voter critical point is split into Ising and Directed percolation (DP) critical points.  Although the Langevin description of GVM is successful, there is no known microscopic version of GVM in two dimensions which clearly presents all three critical points together. We will study one of the possible ways to achieve a microscopic version of GVM with Voter, Ising and DP critical points. 


Organizer: Vinh Nguyen

July 20

Friday 1:30pm
304 Robeson Hall
(poster)

Prof. John B. Phillips (Biological Sciences, Virginia Tech)

"Quantum Biology meets Behavioral Biology (and a Behavioral Biologist): a new sensory system and a new class of sensory receptors in the mammalian retina"

The ability of animals to detect the Earth’s magnetic field remains the least understood of the major senses. Many vertebrates have two functionally distinct magnetoreception mechanisms: a light-dependent, photoreceptor-based mechanism that provides directional (‘compass’) information and a non-light-dependent, magnetite-based mechanism that provides positional (‘map’) information. The light-dependent magnetic compass (LDMC) is mediated by a manifestly quantum process thought to involve a light-dependent radical pair reaction that forms long-lived, spin-coordinated radical pair intermediates (“radical pair mechanism” or RPM). The most compelling evidence for the RPM is the finding that magnetic compass orientation in a variety of animals can be altered or abolished by exposure to low-level radio frequency (RF) fields (> 1nT) that can alter the electron-spin dynamics of the radial pair. Interest in the RPM spans a wide range of disciplines, and has been a primary impetus for the emerging field of Quantum Biology. Studies of murine rodents (mice, rats, etc.) have played a central role in both basic and applied (i.e., biomedical) research on mammalian spatial behavior and cognition. A number of well-characterized spatial cells (e.g., head direction cells, place cells, grid cells, boundary vector cells, and velocity cells; see 2014 Nobel Prize in Medicine) underlie a path integration system that encodes the animal’s spatial position as it moves through the environment. However, the spatial circuitry characterized to date only provides accurate navigational information over distances of a few 10s of meters, falling well short of the 100s of meters routinely moved by even small rodents like deer mice (20g) under natural conditions. A magnetic compass sense can dramatically increase both the range and accuracy of a path integration system, as well as play important roles in many other aspects of spatial behavior and cognition. Nevertheless, the consensus of the literature is that murine rodents do not rely on magnetic cues, despite evidence that a magnetic compass is virtually ubiquitous in other animals, including some mammals (bats, mole rats, dolphins). Contrary to the prevailing view in the literature, we have found that mice and rats have a well-developed magnetic compass. However, consistent behavioral and neurophysiological responses to magnetic cues can only be elicited reliably when the testing apparatus is shielded to screen out low-level RF noise. We have also identified photoreceptors in animals as different as flies, frogs, and mice that appear specialized for detection of the geomagnetic field. In this talk, I’ll briefly discuss evidence: (1) that there are a specialized photoreceptors in which the response to light is dependent on the alignment of an earth-strength magnetic field, (2) that in animals where specialized photo-magnetoreceptors are located in the compound eye (flies) or retina (birds, mice), the magnetic field may be perceived as a 3-dimensional pattern of light intensity and/or color superimposed on the animal’s surroundings, (3) that both behavioral and neurophysiological responses to magnetic cues can be altered or abolished by low-level radio frequency noise at intensities commonly found in laboratory environments, and (4) that the magnetic field plays multiple, previously unrecognized, roles in the spatial behavioral and cognition of murine rodents over a variety of spatial scales.


Organizer: Vinh Nguyen

July 27

Friday 1:30pm
304 Robeson Hall
(poster)

Professor Michel Pleimling (Physics, Virginia Tech)

"Aging processes in systems far from equilibrium I: An overview of the phenomenology of physical aging"

Physical aging scaling is encountered in numerous systems with slow dynamics. In this talk I introduce the phenomenology of physical aging and show that many of the characteristic features of physical aging can be understood through the investigation of simple coarsening systems. Dynamical scaling of two-time quantities like the autoresponse and autocorrelation functions is discussed for systems with a single time-dependent length scale.


Organizer: Vinh Nguyen

August 2018
August 3

Friday 1:30pm
304 Robeson Hall
(poster)

Professor Uwe Tauber (Physics, Virginia Tech)

“Interactive Discussion on Applications”


Organizer: Vinh Nguyen

August 10

Friday 1:30pm
304 Robeson Hall
(poster)

Professor Michel Pleimling (Physics, Virginia Tech)

"Aging processes in systems far from equilibrium II: Systems with complex ordering processes"

In this talk I first discuss aging scaling properties of a many-species system undergoing coarsening with non-trivial in-domain dynamics. The second part of the talk is devoted to physical aging in interacting skyrmion matter. Two-time correlation functions are analyzed to study the non-linear stochastic relaxation dynamics in the aging regime.


Organizer: Vinh Nguyen

Center for Soft Matter and Biological Physics Friday Discussion Meetings

Fall 2018

Organizer: Vinh Nguyen

These meetings occur on Fridays from 4:00pm to 5:00pm in Robeson 304 (unless otherwise indicated)

August 2018
August 24

Friday 4:00pm
304 Robeson Hall
(poster)

Faculty Meeting (No CSB Discussion Meeting)

Organizer: Vinh Nguyen

August 31

Friday 4:00pm
304 Robeson Hall
(poster)

Organizer: Vinh Nguyen

September 2018
September 7

Friday 4:00pm
304 Robeson Hall
(poster)

Organizer: Vinh Nguyen

September 14

Friday 4:00pm
304 Robeson Hall
(poster)

Organizer: Vinh Nguyen

September 21

Friday 4:00pm
304 Robeson Hall
(poster)

Deepali Shirsekar (Mechanical Engineering)

“Bidirectional Reflectance Measurement of Black Coating Z302 for use in Optical Instrument Design ”

The bidirectional reflectance distribution function (BRDF) plays a fundamental role in the optical characterization of a surface. The BRDF is a measure of the amount of light incident from one direction that is scattered by a surface in another direction. This talk introduces the concept of BRDF and presents the thesis research of graduate student, Deepali Shirsekar, to investigate the BRDF of black coating, Aeroglaze Z302. Work includes design and fabrication of a high-accuracy bidirectional reflectometer and its use to measure the bidirectional reflectance of a black absorber Aeroglaze Z302®. A BRDF model consisting of diffuse, glossy, and specular components is fitted to the experimental results. Finally, the Monte Carlo ray-trace (MCRT) method is used to simulate the performance of any optical instrument which has Z302 material coated on its active surfaces. 

Organizer: Vinh Nguyen

September 28

Friday 4:00pm
304 Robeson Hall
(poster)

Faculty Meeting (No CSB Discussion Meeting)

Organizer: Vinh Nguyen

October 2018
October 5

Friday 4:00pm
304 Robeson Hall
(poster)

Nazia Munir (Mechanical Engineering)

Organizer: Vinh Nguyen

October 12

Friday 4:00pm
304 Robeson Hall
(poster)

Faculty Meeting (No CSB Discussion Meeting)

Organizer: Vinh Nguyen

October 19

Friday 4:00pm
304 Robeson Hall
(poster)

"Fall Break" (No CSB Discussion Meeting)

Organizer: Vinh Nguyen

October 26

Friday 4:00pm
304 Robeson Hall
(poster)

Harrison Wood (Biomedical Engineering and Mechanics)

Organizer: Vinh Nguyen

November 2018
November 2

Friday 4:00pm
304 Robeson Hall
(poster)

Yanfei Tang (Physics, Virginia Tech)

Organizer: Vinh Nguyen

November 9

Friday 4:00pm
304 Robeson Hall
(poster)

Anum Ashraf (Mechanical Engineering)

Organizer: Vinh Nguyen

November 16

Friday 4:00pm
304 Robeson Hall
(poster)

Faculty Meeting (No CSB Discussion Meeting)

Organizer: Vinh Nguyen

November 23

Friday 4:00pm
304 Robeson Hall
(poster)

Organizer: Vinh Nguyen

November 30

Friday 4:00pm
304 Robeson Hall
(poster)

Mehran Yarahmadi (Mechanical Engineering)

Organizer: Vinh Nguyen

December 2018
December 7

Friday 4:00pm
304 Robeson Hall
(poster)

Organizer: Vinh Nguyen

December 14

Friday 4:00pm
304 Robeson Hall
(poster)

Organizer: Vinh Nguyen

December 21

Friday 4:00pm
304 Robeson Hall
(poster)

Organizer: Vinh Nguyen