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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 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)

Nanoscalecharacterization of periodic surfaces based on dynamicalscattering theory

Precise metrology of nanopatternsis of paramount importance in many applications across different fields,including chemical engineering, optics, electronics, and biology. Althoughdirect characterization approaches such as AFM and SEM are extremely informative,they suffer several limitations including inaccessibility to beneath-surfacestructures or the necessity for sample dissection to obtain in-depthinformation. On the other hand, indirect detection, primarily usingneutron/x-ray scattering, offers an attractive non-destructive approach forprobing in-depth structures. The caveat is that scattering methods requirenon-trivial data modeling based on complex scattering theories. To this end, modelsbased on approximation methods have facilitated and advanced the use ofscattering approaches. However, they are not adequate for modeling signals resultingfrom strong coherent wave interaction, as is in the case of periodicnanostructures. Alternatively, an exact framework for scattering from periodicstructures is given by the dynamical theory (DT) model. Here, we improved anexisting DT fitting protocol by advancing the fitting package,"Pywls," using a python-based package of "Cma-Es". We haveapplied our methodology in reconstructing the profile of different periodicnanostructures using available neutron scattering data. Our approach yields highprecision and efficiency in computational time. Currently, we are optimizingour model to predict shape variations and thin-slicing protocols of complexsample profiles. In this talk, we will discuss the theoretical basis of themodel, current computational developments, and possible applications of thismethod 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 cytoskeletal structures, especially by the active-viscoelastic rheology of the actomyosin cortex. Even in this seemingly simple regime with frozen junctional 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 subcellular processes. We address this gap through a formulation based on Onsager's variational 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, viscoelasticity, and turnover of the cortex. This modeling approach provides a unifying framework to capture epithelial phenomenologies at different loading rates, including 'reinforcement' and 'fluidization' responses following sudden stretch and unstretch, solid and complex-fluid creep responses, transient flattening and stable folding of compression-induced folds in suspended epithelial sheets, pulsatile cellular oscillations, and active-superelasticity. While encapsulating these epithelial phenomenologies, the formulation also provides a common subcellular 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 bioengineering 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)

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 in Robeson 304.
Refreshments are served at 3:45pm (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
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:

February 14

Friday 4:00pm
304 Robeson Hall
(poster)

Host:

February 21

Friday 4:00pm
304 Robeson Hall
(poster)

No Discussion Meeting (Tenure Track Physics Faculty Meeting)

Host:

February 28

Friday 4:00pm
304 Robeson Hall

(poster)

No Discussion Meeting(Special Joint CSB/CM Seminar)

Host:

March 2020
March 6

Friday 4:00pm
304 Robeson Hall

(poster)

"Spring Break" (APS March Meeting)

Host:

March 13

Friday, 4:00pm
304 Robeson Hall

(poster)

"Spring Break"

Host:

March 20

Friday 4:00pm
304 Robeson Hall

(poster)

No Discussion Meeting (CSB Faculty Meeting)

Host:

March 27

Friday 4:00pm
304 Robeson Hall

(poster)

No Discussion Meeting (Physics Faculty Meeting)

Host:

April 2020
April 3

Friday 4:00pm
304 Robeson Hall

(poster)

No Discussion Meeting (Physics Faculty Meeting)

Host:

April 10

Friday 4:00pm
304 Robeson Hall


(poster)

No Discussion Meeting (Due to COVID-19)

Host:

April 17

Friday 4:00pm
304 Robeson Hall

(poster)

No Discussion Meeting (Physics Faculty Meeting)

Host:

April 24

Friday 4:00pm
304 Robeson Hall

(poster)

No Discussion Meeting (Due to COVID-19)

Host:

May 2020
May 1

Friday 4:00pm
304 Robeson Hall
(poster)

No Discussion Meeting (Due to COVID-19)

Host:

May 8

Friday 4:00pm
304 Robeson Hall
(poster)

"Exam Day" (No Meeting)

Host:

May 15

Monday, 4:00pm
304 Robeson Hall
(poster)

"University Commencement "(No Meeting)

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

Fall 2019

Organizer: Vinh Nguyen

These meetings occur on Fridays from 4:00pm to 5:00pm in Robeson 304.
Refreshments are served at 3:45pm (unless otherwise indicated)

August 2019
August 30

Friday 4:00pm
304 Robeson Hall
(poster)

Host:

September 2019
September 6

Friday 4:30pm
304 Robeson Hall
(poster)

Host:

September 13

Friday 4:00pm
304 Robeson Hall
(poster)

Host:

September 20

Friday 4:00pm
304 Robeson Hall
(poster)

.

Host:

September 27

Friday 4:00pm
304 Robeson Hall

(poster)

Host:

October 2019
October 4

Friday 4:00pm
304 Robeson Hall

(poster)

Host:

October 11

Friday 4:00pm
304 Robeson Hall

(poster)

Host:

October 18

Friday 4:00pm
304 Robeson Hall

(poster)

Ahmadreza Azizi (Physics, Virginia Tech)

"Critical Phenomena in Presence of Symmetric Absorbing States"

Phase transitions in non-equilibrium systems have been the subject of many studies in the area of statistical physics. In this talk, I will discuss standard steady-state and time-dependent quantities for models which exhibit a voter-like phase transition, a symmetry-breaking phase transition in absence of bulk noise, and an absorbing phase transition belonging to the Directed Percolation universality class. The Langevin description of systems with two symmetric absorbing states will be introduced and the resulting phase diagram with three different phases (disordered and active, ordered and active, absorbing) separated by critical lines belonging to three different universality classes (generalized voter, Ising, and directed percolation) will be discussed. I also present a proposed microscopic model with two symmetric absorbing states that possesses all the features of the Langevin description.

Advisor: Michel Pleimling

October 25

Friday 4:00pm
304 Robeson Hall

(poster)

Host:

November 2019
November 1

Friday 4:00pm
304 Robeson Hall

(poster)

Host:

November 8

Friday 4:00pm
304 Robeson Hall


(poster)

Host:

November 15

Friday 4:00pm
304 Robeson Hall

(poster)

"TBD"

Host:

November 22

Friday 4:00pm
304 Robeson Hall

(poster)

Host:

November 29

Friday 4:00pm
304 Robeson Hall

(poster)

Thanksgiving Holiday (No Classes)

Host:

December 2019
December 6

Friday 4:00pm
304 Robeson Hall
(poster)

Host:

December 13

Friday 4:00pm
304 Robeson Hall
(poster)

Exam Day (No Classes)

Host:

December 20

Friday 4:00pm
304 Robeson Hall
(poster)

University and Graduate Ceremonies (No Classes)

Host:
December 27

Friday 4:00pm
304 Robeson Hall
(poster)

Holiday (No Classes)

Host:
December 30

Friday 4:00pm
304 Robeson Hall
(poster)

Holiday (No Classes)

Host: