UCSB's Materials Miracle

Total Page:16

File Type:pdf, Size:1020Kb

UCSB's Materials Miracle UCSB’s Materials Miracle: A Blueprint for Success Glenn H. Fredrickson Mitsubishi Chemical Professor, Director MC-CAM Departments of Chemical Engineering and Materials 2010 NRC Rankings: Materials Science & Engineering On September 28, 2010, The National Research Council (NRC) published its long- awaited report evaluating over 5,000 doctoral programs in 62 fields at 212 universities The 2010 rankings specified 5 percentile and 95 percentile confidence intervals using a number of criteria. The most important of these are the so-called S (survey) and R (regression) rankings Only three other programs in the country share UCSB Materials "1111" ranking: Economics at Harvard, Statistics at Stanford, and Performing Arts at NYU Young but Distinguished UCSB College of Engineering: • Founded 1961 – 50 yrs old UCSB Materials Department • Founded 1986 – 25 yrs old How did UCSB get to #1 in less than 25 years? Engineering, top 10 by S In fact, all five College of Engineering (COE) graduate programs in UCSB are "top 10" (when the S ranking is used) We will see that UCSB’s broader success is intimately linked to the success in Materials! Outline . Beginnings (1980-1990) . Prerequisites . Visionaries . Multi-discipline . Maturation (1990-2000) . Shared facilities . Centers . Education and outreach . Recognition (2000-2010) . Closing Remarks Beginnings (1980-1990) Robert Mehrabian Dean, COE 1983-1990 Prerequisites: build from strength By 1980, select areas of UCSB physical science and engineering had established a national reputation for excellence: . Physics Dept – led by an ambitious and talented faculty hired in the 1960s . Institute for Theoretical Physics (est. 1979, now KITP) – used to attract Nobel Laureate R. Schrieffer, F. Wilczek and others . Institute for Polymers and Organic Solids (est. 1982, IPOS, now CPOS) – used to attract A. Heeger, F. Wudl in semiconducting polymers . Electrical and Computer Engineering (ECE) – strategic focus on non-silicon solid state science starting in 1976 The Visionary Around 1980, informal discussions surrounding a materials program were already taking place among R. Odette, G. Lucas, J. Merz, H. Kroemer, A. Heeger, J. Langer and others The effort was catalyzed by the arrival in 1983 of Robert Mehrabian as Dean of the College of Engineering . He was promised 15 FTE . By the time Mehrabian left UCSB in 1990, he had made 69 hires! Robert Mehrabian . 1968-75 – Asst./Assoc. Prof., Materials Science Dept., MIT . 1975-79 – Prof., Materials Science Dept., U. Illinois . 1979-83 – Director, Center for Mat. Sci., NBS . 1983-90 – Dean, COE, UCSB . 1990-97 – President, Carnegie Mellon University . 1999-11 – President, CEO, Chairman, Teledyne Technologies Inc. Mehrabian’s Strategy 1. Initially, build on the strength in ECE in III-V semiconductors and opto- electronics, and develop new initiatives in structural (metallic and ceramic) and macromolecular materials 2. Forge alliances with key administrators and Academic Senate leaders 3. Partner with industry, DOD, and DOE to satisfy startup equipment needs 4. Recruit a leader for the new materials program 5. Nucleate new areas with cluster hires of world-class mid-career faculty, many from industry. Reinforce with junior appointments 6. New faculty are appointed jointly in new Materials Dept and an existing Department Electronic Materials: Building on Strength in ECE . Mehrabian, H. Kroemer, J. Merz, and others forged a strategy around III-V semiconductors, heterojunctions, and optoelectronics . Key hires included . Larry Coldren (1984, Bell Labs, optoelect.) . Evelyn Hu (1984, Bell Labs, micro/nanofabrication) . Pierre Petroff (1986, Bell Labs, quantum structures) . Art Gossard (1987, Bell Labs, MBE growth) Arthur Gossard • NAS, NAE • Co-discoverer, quantum confined Stark effect • Co-discoverer fractional Hall effect • 3-time Winner of the AAAS Newcomb Cleveland Prize • 1078 papers, 43 citations/paper • H-index: 106 Strategic Alliances Robert A. Huttenback Ray Sawyer (Physics) Chancellor 1977-1986 Executive Vice Chancellor Robert Mehrabian ~1982-1986 Dean, COE 1983-1990 I was feeding at the same plate as everyone else, I was just hungrier! Robert Mehrabian, February 2011 AS Committee on Educational Academic Senate Chair Policy and Academic Planning (CEPAP) R. Sawyer (Physics) 1980-81 K. Millett (Math) 1982-83 R. Odette (ME) 1985-1986 B. Kirtman (Chem) 1984-85 G. Taborski (Bio) 1987 D. Mellichamp (ChemE) 1990-92 R. Watts (Chem) 1988-1989 The Leader . In the early 1980s, Mehrabian served on a DARPA advisory committee with Tony Evans of Berkeley/LBL . After more than a year of courting, assisted by J. Langer, R. Schreiffer, A. Heeger and others, Tony decided to come to UCSB to head the new materials program . Tony led the creation of a Materials Department and wrote many successful proposals to the DOD (URI, DARPA, ONR), DOE and NSF Anthony G. Evans •NAS, NAE, FRS •ISI Highly cited author in Materials Science, Engineering & Physics •Prior to UCSB, work experience at NBS, Rockwell, UC Berkeley •Former Chair, Defense Sciences Research Council •Founding Chair, Materials Dept, UCSB 1985-1994 •799 papers, 47 citations/paper •H-index: 97 Foundations of a Program . By the time of the 1986 Materials Dept proposal, the basic structure was in place . Evans and Mehrabian used mid-career cluster hires to seed the structural and polymers areas . Many of these hires had experience at premier corporate research labs: . Bell Labs . IBM . Exxon Corp. Research . DuPont Experimental Station . Rockwell Research Center A. G. Evans, A Proposal for a Department of Materials at UCSB, Feb 1986, pg. 64 “Bell Labs West” UCSB has probably the highest concentration of former Bell Labs employees as current or former faculty: COE alone: . Fred Wudl . John Bowers . Art Gossard . Pierre Petroff . Joe Zasadzinski . Dale Pearson . Glenn Fredrickson . Larry Coldren . Kwang-Ting Cheng . Evelyn Hu . Jim Allen . Mark Rodwell . John Shynk . Sanjit Mitra . Tom Soh . Haitao Zheng . Lawrence Rabiner . … Bell Labs, 600 Mountain Ave., Murray Hill, NJ, 07974 Breaking Down Departmental Barriers New faculty were given joint appointments between the Materials Dept. and existing Depts. in COE and MLPS: . Inter-disciplinary research is the norm . Good for you is good for me . Ideal platform for training students UCSB Materials today Strengthening Other Departments Existing Departments in COE and MLPS derived a significant benefit from the infusion of world-class faculty jointly appointed with Materials Case in point: Chemical Engineering Materials Related Chemical (& Nuclear) Engineering Appointments (1970-2000) . Bob Odette (1970, structure materials/nuclear) . Gene Lucas (1978, structural materials/nuclear) . Phillip Pincus (1985, complex fluids theory, Exxon) . Fred Lange (1986, ceramic processing, Rockwell) . Joe Zasadzinski (1986, complex fluids microscopy, Bell Labs) . Jacob Israelachvili (1986, colloids & surfaces, ANU) . Paul Smith (1987, polymer processing, DSM & DuPont) . Dale Pearson (1987, polymer rheology, Exxon & Bell Labs) . Gary Leal (1989, fluids and polymers, Caltech) . Henry Weinberg (1989, surf. sci. & electronic matls., Caltech) . Glenn Fredrickson (1990, polymer theory, Bell Labs) . Brad Chmelka (1990, inorganic materials, UC Berkeley, 1982 NRC Study – UCSB ChE not rated Unocal) . Eray Aydil (1993, electronic materials processing, U. 1995 NRC Study – UCSB ChE #14 Minnesota) 2011 NRC Study – UCSB ChE #2 . Dmitri Maroudas (1994, computational materials, MIT) . David Pine (1995, soft condensed matter, Exxon) . Edward Kramer (1997, experimental polymer physics, Cornell) . Matthew Tirrell (1999, biopolymer interfaces, U. Minnesota) Maturation (1990-2000) Venky Narayanamurti Dean, COE 1992-1998 Shared Facilities Starting with Mehrabian and Evans, and fully CNSI Building ~10,000 ft2 developed in the 1990s, UCSB pioneered the Microscopy and Microanalysis development of open-access user facilities for materials characterization X-Ray Spectroscopy Today, nearly all new pieces of major equipment are placed in such facilities EII MBE Benefits include: Materials Processing • Broad range of instrumentation MOCVD • Shared/leveraged costs Mechanical Testing • Professional staff to train users and maintain equipment • Facilitate collaborations across UCSB, with other universities and industry ESB ~10,000 ft2 Nanofab MRL Polymer Characterization X-Ray Chemistry MRL Administered Facilities Facility Faculty Supervisor Development Engineer TEMPO: Ram Seshadri Joe Doyle (formerly Chemistry) Computation: Frank Brown Paul Weakliem, Jeffrey J. Barteet (joint with CNSI) Glenn Fredrickson Linda Hall Microscopy James Speck Dr. Jan Lofvander and Microanalysis: (Committee Chair) Dr. Tom Mates Dr. Stefan Kraemer Mark Cornish Spectroscopy Song-I Han Dr. Jerry Hu Nicole Holstrom Polymer Characterization: Craig Hawker Dr. K. Brzezinska X-Ray Diffraction: Cyrus Safinya Dr. Youli Li Morito Divinagracia MRL Facilities Use 2009 User Departments (>12): ECE, Chem. Engr., Materials, Mech. Engr., Biology, Chemistry, Geology, Marine Sci., Physics, CNSI, Environmental Sci., … Research Recharged Facility # of Users Groups Hours (2009) TEMPO 159 41 10,085 Computation 40 6 - Microscopy >289 53 12268 Polymer 187 34 3592 Spectroscopy 161 39 18542 X-Ray 348 54 9076 These facilities enable a spectacular range of materials science across UCSB External Users of MRL Facilities MRL Facilities – External Users – 2008 Start-ups and Small Companies Advantageous Systems Kaai Universities Aerius Photonics Lawrence Berkeley Labs Allergan L3-Infrared
Recommended publications
  • An Investigation Into Jamming Percolation Using Renormalization
    An investigation into jamming percolation using renormalization group methods. Samuel Schoenholz Under the supervision of Professor Amy Bug and Professor Andrea Liu March 22, 2010 1 1 Overview Many systems in nature fail to satisfy the ergodic hypothesis and feature strong nonequilibrium behavior. These systems have proven remarkably difficult to study. In recent years theorists have studied a phase transition known as the jamming phase transition. The jamming phase transition unifies several far from equilibrium phase transitions including: the glass transition, the solidification of granular media in response to shearing forces, and the stiffening of colloids in response to increases in pressure. It has recently been shown that certain correlated percolation models can exhibit behavior analogous to the jamming phase transition. In particular this has been shown for two models, coined the spiral model and the force-balance model. The primary goal of this study was to determine whether or not the spiral model and the force-balance model reside in the same universality class. To investigate this issue we used the renormalization group to perform a numerical investigation of the spiral model and force balance model. There is evidence to suggest that both models feature exponential, as opposed to power-law scaling of the correlation function. It was therefore difficult to investigate, in a computationally feasible way, large enough systems so as to reduce the finite size effects. To do this we came up with a variety of algorithms including: a Monte-Carlo method, a binary search, and a linear time culling algorithm. The combination of these three strategies allowed us to investigate significantly larger systems than had been investigated in the past.
    [Show full text]
  • The Dynamics Is Encoded in the Pair Correlation Function François Landes, Giulio Biroli, Olivier Dauchot, Andrea Liu, David Reichman
    Attractive versus truncated repulsive supercooled liquids: The dynamics is encoded in the pair correlation function François Landes, Giulio Biroli, Olivier Dauchot, Andrea Liu, David Reichman To cite this version: François Landes, Giulio Biroli, Olivier Dauchot, Andrea Liu, David Reichman. Attractive versus truncated repulsive supercooled liquids: The dynamics is encoded in the pair correlation function. Physical Review E , American Physical Society (APS), 2020, 101 (1), 10.1103/PhysRevE.101.010602. hal-02439295 HAL Id: hal-02439295 https://hal.inria.fr/hal-02439295 Submitted on 14 Jan 2020 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. Attractive versus truncated repulsive supercooled liquids: The dynamics is encoded in the pair correlation function Fran¸coisP. Landes,1, 2, 3, 4 Giulio Biroli,2 Olivier Dauchot,5 Andrea J. Liu,3 and David R. Reichman4 1LRI, AO team, B^at660 Universit´eParis Sud, Orsay 91405, France∗ 2Laboratoire de Physique de l'Ecole´ normale sup´erieure, ENS, Universit´ePSL, CNRS, Sorbonne Universit´e, Universit´eParis-Diderot, Sorbonne Paris Cit´e,Paris, France 3Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, PA 19104 4Department of Chemistry, Columbia University, 3000 Broadway, New York, NY 10027, USA 5UMR Gulliver 7083 CNRS, ESPCI ParisTech, PSL Research University, 10 rue Vauquelin, 75005 Paris, France We compare glassy dynamics in two liquids that differ in the form of their interaction poten- tials.
    [Show full text]
  • Arxiv:2006.09592V4 [Cond-Mat.Soft] 21 Apr 2021 13]
    Mean-Field Predictions of Scaling Prefactors Match Low-Dimensional Jammed Packings James D. Sartor∗, Sean A. Ridout†, Eric I. Corwin∗ ∗Department of Physics and Materials Science Institute, University of Oregon, Eugene, Oregon 97403, USA †Department of Physics and Astronomy University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA (Dated: April 22, 2021) No known analytic framework precisely explains all the phenomena observed in jamming. The replica theory for glasses and jamming is a mean-field theory which attempts to do so by working in the limit of infinite dimensions, such that correlations between neighbors are negligible. As such, results from this mean-field theory are not guaranteed to be observed in finite dimensions. However, many results in mean field for jamming have been shown to be exact or nearly exact in low dimensions. This suggests that the infinite dimensional limit is not necessary to obtain these results. In this Letter, we perform precision measurements of jamming scaling relationships between pressure, excess packing fraction, and number of excess contacts from dimensions 2–10 in order to extract the prefactors to these scalings. While these prefactors should be highly sensitive to finite dimensional corrections, we find the mean-field predictions for these prefactors to be exact in low dimensions. Thus the mean-field approximation is not necessary for deriving these prefactors. We present an exact, first-principles derivation for one, leaving the other as an open question. Our results suggest that mean-field theories of critical phenomena may compute more for d du than has been previously appreciated. ≥ Introduction – Granular materials exhibit universal these results.
    [Show full text]
  • Jamming Phase Diagram, Effective Temperature, and Heterogeneous Dynamics of Model Glass-Forming Liquids
    University of Pennsylvania ScholarlyCommons Publicly Accessible Penn Dissertations Summer 2010 Jamming Phase Diagram, Effective Temperature, and Heterogeneous Dynamics of Model Glass-Forming Liquids Thomas K. Haxton University of Pennsylvania, [email protected] Follow this and additional works at: https://repository.upenn.edu/edissertations Part of the Condensed Matter Physics Commons Recommended Citation Haxton, Thomas K., "Jamming Phase Diagram, Effective Temperature, and Heterogeneous Dynamics of Model Glass-Forming Liquids" (2010). Publicly Accessible Penn Dissertations. 235. https://repository.upenn.edu/edissertations/235 This paper is posted at ScholarlyCommons. https://repository.upenn.edu/edissertations/235 For more information, please contact [email protected]. Jamming Phase Diagram, Effective Temperature, and Heterogeneous Dynamics of Model Glass-Forming Liquids Abstract We establish that the behavior of fluids consisting of epulsivr e spheres under the combined effects of pressure p, temperature T, and applied shear stress s can be organized in a jamming phase diagram parameterized by the dimensionless quantities T/pd^3, s/p, and pd^3/e, where d is the diameter of the spheres and e is the interaction energy scale. The jamming phase diagram describes the three- dimensional parameter space as the product of an equilibrium plane at s/p=0 and a hard sphere plane at pd^3/e=0. Near the hard sphere plane, the jamming phase diagram is universal in the sense that material properties are insensitive to the details of the interaction potential. We demonstrate that within the universal regime, the conventional approach to the dynamic glass transition along a decreasing temperature trajectory is equivalent to the colloidal glass transition approach along an increasing pressure trajectory.
    [Show full text]
  • Willens Wing Atrium
    THE MATERIALS SCIENCE AND ENGINEERING DEPARTMENT SERIES PRESENTS THE MATERIALS SCIENCE AND ENGINEERING DEPARTMENT FALL COLLOQUIUM SERIES PRESENTS THE DOW LECTURE Andre Liu Hepburn Professor of Physics, Department of Physics and Astronomy University of Pennsylvania Exploiting the Malleability of Disorder to Design Functional Materials Systems with complex energy landscapes, such as glass-forming systems, have far more variation in their properties than those with simple ones that readily crystallize. This natural variation can be pushed even further by design, allowing us to tune in unusual properties and novel functions into materials. For example, when most materials are stretched in one direction, they tend to shrink in the orthogonal directions. Materials that do the opposite and expand in the orthogonal directions when stretched are “auxetic,” and have attracted attention for applications such as high energy absorption. We have found that mechanical spring networks can be tuned easily to the extreme limit of auxetic behavior. Likewise, we have shown that properties common in living matter, such as the ability of proteins (e.g. hemoglobin) to change their conformations upon binding of an atom (oxygen) or molecule, the ability of the brain’s vascular network to send enhanced blood flow and oxygen to specific areas of the brain associated with a given task, or the ability to retain a memory, can be designed into disordered systems using similar principles. The ability to design properties and functions further gives new insight into the relation between microscopic structure and function that may help us both to understand living systems and to design new biologically-inspired materials.
    [Show full text]
  • Arxiv:1308.6806V2 [Cond-Mat.Soft] 20 Nov 2013
    Mechanical and microscopic properties of the reversible plastic regime in a 2D jammed material Nathan C. Keim∗ and Paulo E. Arratiay Department of Mechanical Engineering and Applied Mechanics, University of Pennsylvania, Philadelphia, PA 19104 (Dated: August 31, 2018) At the microscopic level, plastic flow of a jammed, disordered material consists of a series of particle rearrangements that cannot be reversed by subsequent deformation. An infinitesimal de- formation of the same material has no rearrangements. Yet between these limits, there may be a self-organized plastic regime with rearrangements, but with no net change upon reversing a defor- mation. We measure the oscillatory response of a jammed interfacial material, and directly observe rearrangements that couple to bulk stress and dissipate energy, but do not always give rise to global irreversibility. PACS numbers: 83.60.La,63.50.Lm,62.20.F-,05.65.+b The mechanical properties of disordered (amorphous) than any global timescale of deformation (e.g. a period materials far from equilibrium | from sand, to plas- of driving or the inverse strain rateγ _ −1), we can describe tics, to ice cream | continue to elude comprehensive changes to microstructure in terms of discrete, local plas- understanding [1{3]. These materials typically feature tic rearrangements, which are a key feature of the shear many particles (e.g. droplets, atoms, or grains) that are transformation zone (STZ) picture of plasticity [8, 9]. crowded together in close contact, and are both jammed Under steady shear, the piling-on of these events, each of so that each particle is fully constrained by its neighbors, which traverses a barrier between two local minima in po- and disordered so that these constraints vary greatly tential energy, ensures that the initial microstructure can among particles, and crystalline order rarely extends be- never be recovered out of a vast landscape of metastable yond several particle diameters [4].
    [Show full text]
  • Relationships Among Structure, Memory, and Ow in Sheared
    Relationships among structure, memory, and ow in sheared disordered materials Kevin Galloway Department of Mechanical Engineering and Applied Mechanics, University of Pennsylvania https://orcid.org/0000-0001-8407-6923 Erin Teich Department of Bioengineering, University of Pennsylvania Xiaoguang Ma University of Pennsylvania Christoph Kammer Department of Mechanical Engineering and Applied Mechanics, University of Pennsylvania Ian Graham Department of Physics and Astronomy, University of Pennsylvania Nathan Keim Department of Physics, Pennsylvania State University Celia Reina Department of Mechanical Engineering and Applied Mechanics, University of Pennsylvania Douglas Jerolmack Department of Earth and Environmental Science, University of Pennsylvania Arjun Yodh University of Pennsylvania https://orcid.org/0000-0003-4744-2706 Paulo Arratia ( [email protected] ) University of Pennsylvania Article Keywords: disordered solids, microscopy, microstructural properties, rheological response Posted Date: May 26th, 2021 DOI: https://doi.org/10.21203/rs.3.rs-523661/v1 License: This work is licensed under a Creative Commons Attribution 4.0 International License. Read Full License 1 Relationships among structure, memory, and flow in 2 sheared disordered materials 1 2 3 1 3 3 K.L. Galloway ,E.G.Teich, X-g Ma ,Ch.Kammer,I.R.Graham & N.C. Keim4,C.Reina1, D.J. Jerolmack5,1, A. G. Yodh3, P.E. Arratia∗,1 1Department of Mechanical Engineering and Applied Mechanics, University of Pennsylvania 2Department of Bioengineering, University of Pennsylvania 3Department of Physics and Astronomy, University of Pennsylvania 4Department of Physics, Pennsylvania State University 5Department of Earth and Environmental Science, University of Pennsylvania 4 May 13, 2021 5 Abstract 6 A fundamental challenge for disordered solids is predicting macroscopic yield from the 7 microscopic arrangements of constituent particles.
    [Show full text]
  • Criticality in the Linear Response of Disordered Solids Carl Peter Goodrich University of Pennsylvania, [email protected]
    University of Pennsylvania ScholarlyCommons Publicly Accessible Penn Dissertations 1-1-2015 Unearthing the Anticrystal: Criticality in the Linear Response of Disordered Solids Carl Peter Goodrich University of Pennsylvania, [email protected] Follow this and additional works at: http://repository.upenn.edu/edissertations Part of the Physics Commons Recommended Citation Goodrich, Carl Peter, "Unearthing the Anticrystal: Criticality in the Linear Response of Disordered Solids" (2015). Publicly Accessible Penn Dissertations. 1743. http://repository.upenn.edu/edissertations/1743 This paper is posted at ScholarlyCommons. http://repository.upenn.edu/edissertations/1743 For more information, please contact [email protected]. Unearthing the Anticrystal: Criticality in the Linear Response of Disordered Solids Abstract The fact that a disordered material is not constrained in its properties in the same way as a crystalline one presents significant and yet largely untapped potential for novel material design. However, unlike their crystalline counterparts, disordered solids are not well understood. Though currently the focus of intense research, one of the primary obstacles is the lack of a theoretical framework for thinking about disorder and its relation to mechanical properties. To this end, we study a highly idealized system composed of frictionless soft spheres at zero temperature that, when compressed, undergos a jamming phase transition with diverging length scales and clean power-law signatures. This critical point is the cornerstone of a much larger ``jamming scenario" that has the potential to provide the essential theoretical foundation that is sorely needed to develop a unified understanding of the mechanics of disordered solids. We begin by showing that jammed sphere packings have a valid linear regime despite the presence of a new class of ``contact nonlinearities," demonstrating that the leading order behavior of such solids can be ascertained by linear response.
    [Show full text]
  • Shear-Induced Stress Relaxation in a Two-Dimensional Wet Foam
    Shear-Induced Stress Relaxation in a Two-Dimensional Wet Foam John Lauridsen Michael Twardos Michael Dennin Department of Physics and Astronomy and Institute for Interfacial and Surface Science University of California at Irvine Irvine, CA 92697-4575. (November 16, 2018) somewhat model dependent. Various models of two- dimensional foams have been used to study the connec- We report on experimental measurements of the flow be- tion between topological rearrangements and flow prop- havior of a wet, two-dimensional foam under conditions of slow, steady shear. The initial response of the foam is elastic. erties as a function of applied rate of strain [6–13]. All Above the yield strain, the foam begins to flow. The flow con- of these simulations predict the same qualitative behav- sists of irregular intervals of elastic stretch followed by sudden ior for the macroscopic flow for sufficiently small rates of reductions of the stress, i.e. stress drops. We report on the strain that was described above: elastic behavior below a distribution of the stress drops as a function of the applied yield strain and nonlinear bubble rearrangements above shear rate. We also comment on our results in the context of the yield strain. However, the quantitative predictions various two-dimensional models of foams. for the size distribution and frequency of these events are model dependent. The dependence is predominately due 83.80.Iz,82.70.-y to different assumptions concerning the source of dissipa- tion in foams and treating foams with different degrees of Foams are ubiquitous in nature [1] and part of a larger “dryness”.
    [Show full text]
  • Self-Assessment
    Self-Statement for Merit Action, Effective 7/1/20 Mason A. Porter, 8/29/19 This document covers scholarship, teaching, etc. since 1 December 2017, when I submitted my documents for promotion from Step 3 to Step 4 of the professorial ladder. The current submission is for a one-year acceleration to advance to Step 5. In addition to the Department of Mathematics, I am also affiliated with UCLA’s Bhaumik Institute for Theoretical Physics. Scholarship I continue to conduct research in network analysis, data science, complex systems, and nonlinear systems — including contributions to theory, algorithms, data analysis, and applications. A defining feature of my work continues to be its interdisciplinary nature, including recent publications in mathematics, physics, biology, social science, and multidisciplinary journals. Papers: New peer-reviewed papers accepted in final form and/or published: 26, including ones in PNAS, SIAM Journal on Mathematics of Data Science, Nature Neuroscience, Nature Communications, and Chaos New papers (i.e., completed since 1 December 2017) that are currently undergoing peer review or revision based on referee reports: 17 My work is being cited at an ever-increasing rate, with (according to Google Scholar) now about 15000 citations overall, including more than 2700 citations in 2018. This includes one paper from 2018 with more than 30 citations and three papers from 2017 with more than 100 citations. I work in a large variety of areas in network analysis, complex systems, and nonlinear systems; I will highlight three themes here. One major theme of my research the past two years has been theory, methods, data analysis, and applications of multilayer networks, a concept I helped originate (with our 2014 review article [A121] getting more than 400 citations in 2018 and about 300 so far in 2019).
    [Show full text]
  • Villanova University Mechanical Engineering
    VILLANOVA UNIVERSITY MECHANICAL ENGINEERING DEPARTMENT Fall 2019 SEMINAR SERIES Seminar Date: September 6th, 2019 Lecture: Exploiting the Malleability of Disorder to Design Mechanical Metamaterials Speaker: Andrea Liu, Ph.D. Professor Department of Physics, University of Pennsylvania Abstract: Disordered solids have far more variation in their properties than crystalline ones. This natural variation can be pushed even further by design, allowing us to tune in unusual properties and novel functions into materials. For example, when most materials are stretched in one direction, they tend to shrink in the orthogonal directions. Materials that expand in the orthogonal directions when stretched are “auxetic,” and have attracted attention for properties such as high energy absorption for applications. We have found that mechanical spring networks can be tuned easily to the extreme limit of auxetic behavior. Moreover, we have shown that complex properties common in living matter, such as the ability of proteins (e.g. hemoglobin) to change their conformations upon binding of an atom (oxygen) or molecule, the ability of the brain’s vascular network to send enhanced blood flow and oxygen to specific areas of the brain associated with a given task, or the ability to retain a memory, can be designed into disordered systems using similar principles. Biography: Dr. Andrea Liu is a theoretical soft and living matter physicist who received her A. B. and Ph.D. degrees in physics at the University of California, Berkeley, and Cornell University, respectively. She was a faculty member in the Department of Chemistry and Biochemistry at UCLA for ten years before joining the Department of Physics and Astronomy at the University of Pennsylvania in 2004.
    [Show full text]
  • Coffee-Rings and Glasses: Colloids out of Equilibrium
    COFFEE-RINGS AND GLASSES: COLLOIDS OUT OF EQUILIBRIUM Peter Joseph Yunker A DISSERTATION in Physics and Astronomy Presented to the Faculties of the University of Pennsylvania in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy 2012 Arjun G. Yodh, James M. Skinner Professor of Science Supervisor of Dissertation A.T. Charlie Johnson, Associate Professor of Physics Graduate Group Chairperson Dedication To my family ii Acknowledgements No man is an island, and even if a graduate student lives alone on an island, no thesis is written alone. I owe a great debt of gratitude to a large number of people. I’ll start with those who were with me from the beginning, my parents and siblings. Their love and support is an integral part of who I am today. My parents nurtured my interest in science and technology from a young age, taught me to figure things out on my own, and encouraged me to find a vocation that is also my avocation. Next, I must thank my fiance e´ and best friend, Erin Buckley. Erin is always there for me, and there’s no one in the world I would rather spend time with. From our marathon-first-date in New York, to our engagement to in Paris, I’ll always treasure the time we spent together in grad school. I am tremendously grateful to my advisor, Arjun Yodh. Arjun has been my ideal mentor. He encourages creativity, and allows students to invent and pursue their own ideas - with the under- standing that you explain and justify these ideas and experiments in gory detail.
    [Show full text]