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Discussion Meetings

Due to the Covid-19 pandemic all Fall 2020 and Spring 2021 Discussion Meetings will be Virtual.

Zoom Links will be provided on the calendar and through email.

Center for Soft Matter and Biological Physics Friday Discussion Meetings

Fall 2021

Organizer: Vinh Nguyen

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

September 2021
September 24

Friday 4:00pm
Virtual Meeting
(Zoom Link)

Host: Vinh Nguyen

October 2021
October 8

Friday 4:00pm
Virtual Meeting
(Zoom Link)
(poster)

Host: Vin Nguyen

October 29

Friday 4:00pm
Virtual Meeting
(Zoom Link)

Host: Vinh Nguyen

November 2021
November 5

Friday 4:00pm
Virtual Meeting
(Zoom Link)
(poster)

Host: Vinh Nguyen

November 19

Friday 4:00pm
Virtual Meeting
(Zoom Link)
(poster)

Host: Vinh Nguyen

December 2021
December 3

Friday 4:00pm
Virtual Meeting
(Zoom Link)
(poster)

Host: Vinh Nguyen

Center for Soft Matter and Biological Physics Friday Discussion Meetings

Summer 2021

Organizer: Vinh Nguyen

These meetings occur on Mondays from 4:00pm to 5:00pm
Virtual Meeting (unless otherwise indicated)

June 2021
June 7

Monday 4:00pm
Zoom Link
(poster)

Dr. James McClure (Advanced Research Computing, Virginia Tech)

"Digital Scavenger Hunt: is the geometry of complex micro-structure unique?"

Host: Vinh Nguyen

June 14

Friday 4:00pm
Joint REU/CSBM Discussion Meeting
Zoom Link
(poster)

Prof. Uwe Tauber (Physics, Virginia Tech)

"How to Write a Paper"

Host: Vinh Nguyen

June 21

Friday 4:00pm
Zoom Link
(poster)

Sean McMahon (Physics, Virginia Tech)

"Mechanical Limitations of Clostridium Perfringens Chains"

Host: Vinh Nguyen

June 28

Friday 4:00pm
Zoom Link
(poster)

Navid Ghaffarzadegan ( Industrial and Systems Engineering, Virginia Tech)

"Epidemic Forecasting: Why Did Most COVID-19 Models Fail"

Host: Vinh Nguyen

July 2021
July 5

Monday 11:00am
Zoom Link
(poster)

Ruslan Mukhamadiarov (Physics, Virginia Tech)

"Critical Dynamics of the Susceptible-Infectious-Recovered (SIR) Model on a Lattice"

Host: Vinh Nguyen

July 12

Monday 3:00pm
Special Time
Zoom Link
(poster)

Dr. Johannes Zierenberg (Max Planck Institute for Dynamics and Self-Organization, Gottingen and Georg August University )

"Temporal resonance between disease progression and contact patterns shapes epidemic spread"

The spread of a contagious disease is clearly affected by the contact behavior of infected individuals. Previous modelling studies have highlighted both spatial aspects, such as influential spreaders, as well as temporal aspects, such as bursts of contacts. However, it remains unclear how the spatio-temporal contact behavior inter plays with the temporal progression of a disease. Here, we use data from the Copenhagen Network Study to show that resonances between disease progression and temporal contact patterns shape epidemic spread. The temporal network of physical proximity generates, on the level of individuals, periods of statistically high or low encounter probability as a function of time from previous encounters. Considering previous encounters as potential times of infection, we find that the often-neglected latent period of a disease affects the number of potentially infectious encounters during an otherwise fixed infectious period by aligning the infectious period with periods of high or low encounter probability. We demonstrate that this resonance effect can be reproduced when describing individual contact patterns as in homogeneous Poisson processes (temporal aspect) with heterogeneously distributed mean rates (spatial aspect). Focusing on the in homogeneous temporal aspect in a mean-field spreading model, we show that resonances between disease progression and contact patterns affect the basic reproduction number and shape epidemic spread.

Host: Vinh Nguyen

July 19

Monday 4:00pm
Zoom Link
(poster)

Yifei Wang (Physics, Virginia Tech)

"Graphene Mid-infrared Photodetectors Based on Blocked Silicon Impurity Bands"

Host: Vinh Nguyen

July 26

Monday 4:00pm
Zoom Link
(poster)

Teshani Kumarage (Physics, Virginia Tech)

"Biophysical effects of Melatonin and Azithromycin on Model Pulmonary Membranes"

Host: Vinh Nguyen

August 2021
August 2

Monday 4:00pm
Zoom Link (poster)

Ronald Dickman (Universidade Federal de Minas Gerais, Brazil)

TBD

Host: Vinh Nguyen

August 9

Monday 4:00pm
Zoom Link
(poster)

TBD

"TBD"

Host: Vinh Nguyen

August 16

Monday 4:00pm
Zoom Link
(poster)

No CSB Discussion Meeting

Host:

Center for Soft Matter and Biological Physics Friday Discussion Meetings

Spring 2021

Organizer: Vinh Nguyen

These meetings occur on Fridays from 4:00pm to 5:00pm, Virtual Zoom
(unless otherwise indicated)

January 2021
January 29

Friday 4:00pm
Zoom Link
(slides)

Prof. Uwe Tauber (Physics, Virginia Tech)

"Writing useful referee reports and helpful responses"

Slides: "Juan-Jose Lietor-Santos, Physical Review E (2020)"

Host: Vinh Nguyen

February 2021
February 12

Friday, 4:00pm
Zoom Link
(poster)

Ranit Mukherjee (Mechanical Engineering, Virginia Tech)

"To Jump, or not to Jump, that is the Question"

Host: Vinh Nguyen

February 19

Friday 4:00pm
Zoom Link
(poster)

James Stidham (Physics, Virginia Tech)

"Magnetic Skyrmion Motion in a Channel"

Host: Vinh Nguyen

March 2021
March 5

Friday 4:00pm
Zoom Link

(poster)

APS Practice Talks (Uwe Tauber's Group)

Host: Vinh Nguyen

March 12

Friday, 4:00pm
Zoom Link

(poster)

Prof. Justin Barone (Biological Systems Engineering, Virginia Tech)

"What can Gummy Bears Teach us about Biological Elastomers?"

Host: Vinh Nguyen

April 2021
April 2

Friday 4:00pm
Zoom Link

(poster)

Dr. Sudipta Gupta (Physics, Virginia Tech)

"A Scattering Approach to Self-Assembled BioSoft Materials"

Host: Vinh Nguyen

April 16

Friday 4:00pm
Zoom Link


(poster)

Yisheng Huang (Physics, Virginia Tech)

"Chain Conformations and Phase Separations in Polymer Solutions at Various Polymer-Solvent Interactions"

Host: Vinh Nguyen

April 30

Friday 4:00pm
Zoom Link

(poster)

No Discussion Meeting

Host: Vinh Nguyen

May 2021
May 7

Friday 4:00pm
Zoom Link
(poster)

No Discussion Meeting

Host:

Center for Soft Matter and Biological Physics Friday Discussion Meetings

Fall 2020

Organizer: Vinh Nguyen

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

September 2020
September 4

Friday 4:00pm
Virtual Meeting
(Zoom Link)

Prof. William Ducker (Chemical Engineering, Virginia Tech)

"A Surface Coating that Inactivates SARS-CoV-2"

Host: Vinh Nguyen

September 11

Friday 4:00pm
Virtual Meeting
(Zoom Link)

No CSB Meeting

Host:

September 18

Friday 4:00pm
Virtual Meeting
(Zoom Link)

No CSB Meeting

Host:

September 25

Friday 4:00pm
Virtual Meeting
(Zoom Link)

No CSB Meeting

Host:

October 2020
October 2

Friday 4:00pm
Virtual Meeting
(Zoom Link)
(poster)

Hadi Rahmaninejad (Physics, Virginia Tech)

Nano-scale Characterization of Periodic Surfaces Based on Dynamical Scattering Theory

Precise metro-logy of nano patterns is of paramount importance in many applications across different fields,including chemical engineering, optics, electronics, and biology. Although direct characterization approaches such as AFM and SEM are extremely informative,they suffer several limitations including inaccessibility to beneath-surface structures or the necessity for sample dissection to obtain in-depth information. On the other hand, indirect detection, primarily using neutron/x-ray scattering, offers an attractive non-destructive approach for probing in-depth structures. The caveat is that scattering methods require-non-trivial data modeling based on complex scattering theories. To this end, models based on approximation methods have facilitated and advanced the use of scattering approaches. However, they are not adequate for modeling signals resulting from strong coherent wave interaction, as is in the case of periodic nano structures. Alternatively, an exact framework for scattering from periodic structures is given by the dynamical theory (DT) model. Here, we improved an existing DT fitting protocol by advancing the fitting package,"Pywls," using a python-based package of "Cma-Es". We have applied our methodology in reconstructing the profile of different periodic nano structures using available neutron scattering data. Our approach yields high precision and efficiency in computational time. Currently, we are optimizing our model to predict shape variations and thin-slicing protocols of complex sample profiles. In this talk, we will discuss the theoretical basis of the model, current computational developments, and possible applications of this method in relevant research areas.

Host: Vin Nguyen

October 9

Friday 4:00pm
Virtual Meeting
(Zoom Link)
(poster)

Dr. Wenya Shu (Physics, Virginia Tech)

"Multi-physics Modeling of Complex Materials and Structures "

Many structures in aerospace, civil and mechanical systems, work in severe environments and exhibit complex responses. An improved understanding of the service performance of complex structures demands multi-field modeling techniques with great efficiency and high-fidelity.Progress in material science also advances manufacturing of high-performance materials, making it essential to characterize the multi-physics properties of complex materials. In this talk, the speaker will introduce computational methods and formulations of theoretical models for coupled multi-physics modeling’s of materials and structures that exhibit complex system behaviors, with specific interest on carbon nano-tubes (CNTs)-reinforced composites and thin-walled structures The presentation will first briefly discuss a locking-free solid-shell element for the large-deformation therm o-mechanical analyses of thin walled structures.Numerical examples demonstrate the proposed element can achieve the accuracy of the high-order element with more than 85% reduction of computational cost.Next, a computational framework will be presented for coupled therm o-mechanical analyses of interface separation and heat transport in carbon nano-tubes (CNTs)enhanced composites, providing an alternative to molecular dynamics in carrying out multi-physics simulation of CNT-composites with less computational cost. The study indicates that composites containing higher volume fraction or better alignment of CNTs may not have more better mechanical behavior in therm o-mechanical loading. Lastly, the speaker will introduce two analytical methods, which are based on the shear-lag model and the multi-scale homogenization concept respectively, to efficiently characterize mechanical properties of composites with interface debonding.

Host: Vinh Nguyen

October 16

Friday 4:00pm
Virtual Meeting
(Zoom Link)

Fall Break (No CSB Discussion Meeting)

Host: Vinh Nguyen

October 23

Friday 4:00pm
Virtual Meeting
(Zoom Link)

No CSB Meeting

Host:

October 30

Friday 4:00pm
Virtual Meeting
(Zoom Link)
(poster)

Center Faculty Meeting ( No CSB Discussion Meeting)

Host:

November 2020
November 6

Friday 4:00pm
Virtual Meeting
(Zoom Link)
(poster)

Tiffany Roach (Biological Science, Virginia Tech)

"Adaptor Functions of TOM1 in Health and Disease"

Host: Vinh Nguyen

November 13

Friday 4:00pm
Virtual Meeting
(Zoom Link)
(poster)

Prof. Sohan Kale Mechanical Engineering, Virginia Tech)

" From Active-gel Theory of Actomyosin Cortex to Dynamic Vertex Models of Epithelial Mechanics"

Epithelial tissues are cohesive cellular sheets of adherent cells that line organs surfaces and cavities in our bodies. These bio-interfaces act as physical barriers against pathogens, regulate chemical transport, and compartmentalize our bodies into different functional units. Epithelial sheets maintain their mechanical integrity under dynamic conditions with mechanical loading of varied magnitudes and at wide range of loading rates. Moreover, various morphogenetic modules have revealed that epithelia can be shaped into functional 3D structures under the action of active internal and passive external forces. At intermediate timescales of seconds to minutes, epithelial mechanics is governed by the architecture and dynamics of cytology-skeletal structures, especially by the active-viscoelastic rheology of the actomyosin cortex. Even in this seemingly simple regime with frozen junction-al network, a rich phenomenology of epithelial behaviors governed by cortical dynamics has been recently discovered. Yet, a connection between cortical rheology and theoretical tissue-scale models of epithelia has been lacking. For instance, in vertex models of epithelial, phenomenological work functions governing the vertex dynamics are used that often lack a direct connection to the dynamic sub-cellular processes. We address this gap through a formulation based on Onsager's variation-al principle which allows us to coarse-grain active-gel models of the actomyosin cortex to tissue-scale vertex models. The tissue-scale rheology naturally emerges from the coupling between cell shapes and activity, visco elasticity, and turnover of the cortex. This modeling approach provides a unifying framework to capture epithelial phenomenology at different loading rates, including 'reinforcement' and 'fluidization' responses following sudden stretch and un-stretch, solid and complex-fluid creep responses, transient flattening and stable folding of compression-induced folds in suspended epithelial sheets, pulsatile cellular oscillations, and active-super-elasticity. While encapsulating these epithelial phenomenology, the formulation also provides a common sub-cellular origin for seemingly disconnected tissue-scale behaviors. Bio: Dr. Sohan Kale is an Assistant Professor in the Department of Mechanical Engineering at Virginia Tech. The overarching theme of the research in his ‘Mechanics of Living Materials Lab’ is to develop robust and high-fidelity models for complex bio-chemo-mechanical cellular and multicellular behaviors relevant in physiology, pathological conditions, and bio-engineering applications. The research employs diverse set of topics and techniques from computational mechanics, soft matter, non-equilibrium processes, inverse problems, and homogenization. Dr. Kale received his MS and PhD in Mechanical Engineering from University of Illinois at Urbana-Champaign in 2017. Following that, he was a postdoctoral scholar at UPC-Barcelona in the Mathematical and Computational Modeling (Lacan) group. He is a recipient of the Outstanding Dissertation Award from the Mechanical Engineering department and Mavis Future Faculty Fellow award from the college of engineering at UIUC.

Host: Vinh Nguyen

November 20

Friday 4:00pm
Virtual Meeting
(Zoom Link)

No CSB Meeting

Host:

November 27

Friday 4:00pm
Virtual Meeting
(Zoom Link)

Thanksgiving Holiday (No Classes)

Host:

November 29

Friday 4:00pm
Virtual Meeting
(Zoom Link)

Thanksgiving Holiday (No Classes)

Host:

December 2020
December 4

Friday 4:00pm
Virtual Meeting
(Zoom Link)
(poster)

Prof. Michel Pleimling (Physics, Virginia Tech)

"Dynamic Phase Transitions in the Ising Ferromagnet: Bulk and Surface Phase Diagrams"

An interesting type of non-equilibrium criticality is encountered when kinetic ferromagnets are subjected to a periodically oscillating magnetic field. When increasing the frequency of the field, a phase transition takes place between a dynamically disordered phase at low frequencies, where the ferromagnet is able to follow the changes of the field, and a dynamically ordered phase at high frequencies, where the magnetic system does not have time to adjust to the magnetic field before it changes its orientation. In this talk I discuss the bulk and surface properties of this dynamic phase transition. For bulk systems this non-equilibrium phase transition belongs to the  universality class of the equilibrium three-dimensional Ising model. We find, however, that the non-equilibrium surface  exponents do not coincide with those of the equilibrium critical surface. Whereas the resulting non-equilibrium surface phase diagram strongly resembles the corresponding equilibrium phase diagram, with an ordinary transition, an extraordinary transition and a surface transition, for weak surface couplings the non-equilibrium surface does not order. These results indicate that our understanding of the role played by surfaces in non-equilibrium systems, and more specifically at non-equilibrium phase transitions, is far from being complete. 

Host: Vinh Nguyen

December 11

Friday 4:00pm
Virtual Meeting
(Zoom Link)

Fall Semester Exams (No CSB Meeting)

Host: Vinh Nguyen

December 18

Friday 4:00pm
Virtual Meeting
(Zoom Link)
(poster)

University & Graduate Commencement Ceremonies
No CSB Meeting

Host: Vinh Nguyen
December 30

Friday 4:00pm
Virtual Meeting
(Zoom Link)

Holiday (No Classes)

Host:
Center for Soft Matter and Biological Physics Friday Discussion Meetings

Summer 2020

Organizer: Vinh Nguyen

These meetings occur on Mondays from 4:00pm to 5:00pm
Virtual Meeting (unless otherwise indicated)

June 2020
June 1

Monday 4:00pm
Zoom Link
(poster)

Prof. Uwe Tauber (Physics, Virginia Tech)

"Introduction to Critical Phenomena and the Renormalization Group, Part 1"

Host: Vinh Nguyen

June 8

Friday 4:00pm
Zoom Link
(poster)

Prof. Uwe Tauber (Physics, Virginia Tech)

"Introduction to Critical Phenomena and the Renormalization Group, Part 2"

Host: Vinh Nguyen

June 15

Friday 4:00pm
Zoom Link
(poster)

Prof. Uwe Tauber (Physics, Virginia Tech)

"Introduction to Critical Phenomena and the Renormalization Group, Part 3"

Host: Vinh Nguyen

June 22

Friday 4:00pm
Zoom Link
(poster)

Shengfeng Cheng (Physics, Virginia Tech)

"A Coupled two-species model for the pair contract process with diffusion"

Host: Vinh Nguyen

June 29

Monday 4:00pm
Zoom Link
(poster)

Ruslan Mukhamadiarov (Physics, Virginia Tech)

"Temperature Interfaces in the Katz-Lebowitz Spohn Driven Lattic Gas"

Host: Vinh Nguyen

July 2020
July 6

Monday 4:00pm
Zoom Link
(poster)

Binghan Liu (Physics, Virginia Tech)

"Molecular Dynamics Modeling of Liquid-Liquid Mixtures"

Host: Vinh Nguyen

July 13

Monday 4:00pm
Zoom Link
(poster)

Priyanka (Physics, Virginia Tech)

"Effect of Control on One Dimensional Surface Growth Processes"

Host: Vinh Nguyen

July 27

Monday 4:00pm
Zoom Link
(poster)

Prof. Vinh Nguyen (Physics, Virginia Tech)

"Monte Carloray-trace diffraction method for studying Fresnel zone plate lens andphoton-sieve"

Host: Vinh Nguyen

August 2020
August 3

Monday 4:00pm
Zoom Link (poster)

Chengyuan Wen (Physics, Virginia Tech)

Molecular Dynamics Simulations of DNA

Host: Vinh Nguyen

August 10

Monday 4:00pm
Zoom Link
(poster)

Prof. Uwe Tauber

"Individual-basedsimulations of stochastic epidemic models: controlling disease outbreaks"

Host: Vinh Nguyen

August 17

Monday 4:00pm
Zoom Link
(poster)

No CSB Discussion Meeting

Host:

Center for Soft Matter and Biological Physics Friday Discussion Meetings

Spring 2020

Organizer: Vinh Nguyen

These meetings occur on Fridays from 4:00pm to 5:00pm
Virtual Zoom
Due to COVID-19 some Discussion Meetings were canceled.(unless otherwise indicated)

January 2020
January 24

Friday 4:00pm
304 Robeson Hall
(poster)

No Discussion Meeting (Physics Faculty Meeting)

Host:

January 31

Friday 4:00pm
304 Robeson Hall
(poster)

No Discussion Meeting (Physics Faculty Meeting)

Host:

February 2020
February 7

Friday, 4:00pm
Zoom Link
304 Robeson Hall
(poster)

Dr. Abhishek Singh (Physics, Virginia Tech)

"Insights into Hydration Dynamics at Sub-picosecond Timescales"

The liquid state of water is a very complex system due to hydrogen bonding characteristics. Water forms a transient tetrahedral network with neighboring molecules with a life time of the order of picoseconds. The presence of biomolecules in water matrix distorts the H-bond network and makes the water dynamics slower as a results of hydrogen bonding between biomolecule and water. The electrostatic field exerted by a biomolecules gradually weakens as a function of intermolecular distance between biomolecule and water. This results in hydration layers at the surface of a biomolecule, with hydration water molecules having distinct temporal characteristics. I will talk about some of our recent results on the aqueous solutions of DNA, studied employing an extended megahertz-terahertz frequency domain spectroscopy. Based on the spatio-temporal behavior, water molecules in the aqueous DNA solutions can be classified as tightly-, loosely bound, and bulk water. I will further discuss effective medium approximation at terahertz frequencies for such systems.

Host: Vinh Nguyen

February 14

Friday 4:00pm
Zoom Link
(poster)

No Discussion Meeting

Host:

February 21

Friday 4:00pm
Zoom Link
(poster)

No Discussion Meeting (Tenure Track Physics Faculty Meeting)

Host:

February 28

Friday 4:00pm
Zoom Link

(poster)

No Discussion Meeting

Host:

March 2020
March 6

Friday 4:00pm
Zoom Link

(poster)

"Spring Break" (APS March Meeting)

Host:

March 13

Friday, 4:00pm
Zoom Link

(poster)

"Spring Break"

Host:

March 20

Friday 4:00pm
Zoom Link

(poster)

No Discussion Meeting (CSB Faculty Meeting)

Host:

March 27

Friday 4:00pm
Zoom Link

(poster)

No Discussion Meeting (Physics Faculty Meeting)

Host:

April 2020
April 3

Friday 4:00pm
Zoom Link

(poster)

No Discussion Meeting (Physics Faculty Meeting)

Host:

April 10

Friday 4:00pm
Zoom Link


(poster)

No Discussion Meeting (Due to COVID-19)

Host:

April 17

Friday 4:00pm
Zoom Link

(poster)

No Discussion Meeting (Physics Faculty Meeting)

Host:

April 24

Friday 4:00pm
Zoom Link

(poster)

No Discussion Meeting (Due to COVID-19)

Host:

May 2020
May 1

Friday 4:00pm
Zoom Link
(poster)

No Discussion Meeting (Due to COVID-19)

Host:

May 8

Friday 4:00pm
Zoom Link
(poster)

"Exam Day" (No Meeting)

Host:

May 15

Monday, 4:00pm
Zoom Link
(poster)

"University Commencement "(No Meeting)

Host: