Spring 2018

Accelerating Your Research with No-Cost Resources for Computing, AI, and Data with PSC

Speaker(s): 
Nick Nystrom
Dates: 
Wednesday, May 9, 2018 - 3:30pm to 4:30pm

Pittsburgh Supercomputing Center (PSC) offers powerful resources for computing, artificial intelligence, and data management and analytics that are available at no charge for open research and to support coursework. In this talk, we will survey examples of breakthroughs that are using PSC resources and ways to leverage PSC for your own research. Examples will highlight successes in genomics, AI, neuroscience, engineering, and other fields. We will highlight two PSC resources that provide unique capabilities: Bridges and Anton 2. Bridges converges high-performance computing (HPC), artificial intelligence (AI), and Big Data and offers a familiar, an exceptionally flexible user environment, applicable to whatever data analytics or simulation exceed groups’ local capabilities. Anton 2 is a special-purpose computer that dramatically increases the speed of molecular dynamics (MD) simulations to understand the motions and interactions of proteins and other biologically important molecules over much longer time periods than would otherwise be accessible. We will also describe Compass AI, a new initiative to help the community make the most of emerging hardware and software technologies for AI, develop best practices, provide education and training, and establish collaborations, especially between academia and the private sector. We outline areas of expertise at PSC where we are conducting research and open to additional collaboration. We close with a summary of opportunities to co-locate computational resources at PSC, with possible benefits of saving money, bursting to larger resources when needed, and leveraging PSC’s broad software collection. 

A number of PSC’s scientific staff will be present for discussion at the reception following the seminar. A reception will follow at 4:30pm

Two Dimensional Quantum Materials - An Atomically Thin Platform for Spintronics and Novel Spin Phenomena 

Speaker(s): 
Simranjeet Singh
Dates: 
Tuesday, May 1, 2018 - 4:30pm to 5:30pm

Two dimensional (2D) quantum materials provide a versatile experimental platform to probe spin-dependent novel quantum phenomena emerging at the nanoscale. The possibility of on-demand tuning of spin properties of 2D materials by external knobs such as electric field, substrate engineered proximity, etc., can have far-reaching implications for spintronics. I will discuss our experiments demonstrating a strong modulation of spin currents in bilayer graphene using static and fluctuating proximity exchange fields of a ferromagnetic insulator (FMI). We achieve complete spin modulation in graphene layers by controlling the direction of the exchange field of a nearby magnetic material in graphene/FMI heterostructures. A strong magnetic exchange coupling across the interface in graphene/FMI heterostructures leads to the experimental observation of full spin modulation at low externally applied magnetic fields in mesoscopic graphene spin channels. In graphene/FMI heterostructures, we also discover a novel spin dephasing mechanism due to randomly fluctuating magnetic exchange fields. This is manifested as an unusually strong temperature dependence of the non-local spin signals in graphene, which is due to spin relaxation by thermally-induced transverse fluctuations of the FMI magnetization. 

In the second half of my talk, I will discuss spin-charge interconversion driven by the Rashba effect in van der Waal bonded platinum/graphene (Pt/Gr) heterostructures. The interfacial spin-orbit interaction driven Rashba effect in low-dimensional systems can enable efficient and tunable spin-charge interconversion for spintronics applications. I will show that an applied electric field at the Pt/Gr Rashba interface results in a net spin accumulation in graphene, with spin polarization quantized along a direction transverse to the applied electric field. This current induced non-zero spin accumulation at the Pt/Gr interface is a direct consequence of uncompensated spin-textured Femi surfaces of the graphene Dirac states due to a symmetry-breaking electric field normal to the Pt/Gr heterostructure. Employing the Pt/Gr Rashba interface, we also realize the first experimental demonstration of the Onsager reciprocity between charge and spin via Rashba Edelstein effect (REE) and inverse-REE. This work is a significant advancement in graphene spintronics and provides an alternative experimental approach to generating and detecting spins using extrinsically tunable interfacial spin-orbit phenomena in two-dimensional materials.

Gurjyot Sing Sethi Won the 1st Place in the Annual CMU Energy Week Poster and Multimedia Competition

  • By Burcu Ozden
  • 17 April 2018

The CMU Energy Week Poster and Multimedia Competition is a unique opportunity to showcase your energy-related research and other activities, such as software, videos, art, models or sculptures. Participants will be able to submit either Science, Technology, Engineering and Mathematics (STEM) related or Non-STEM related work. 

The competition was open to Carnegie Mellon undergraduate, master's and PhD students and postdoctoral researchers. 

Gurjyot Sing Sethi won the 1st place in this competition with his poster titled "Identifying the prospects of Electrochemical Ammonia Synthesis using First-Principles Calculations."

He was awarded $1,000.

Gurjyot Sing Sethi is a graduate student in Venkat Viswanathan's group.

Venkat Viswanathan Quoted About Lithium-Air Batteries in Chemistry World

  • By Burcu Ozden
  • 17 April 2018

Chemistry World quoted Venkat Viswanathan on the cycle life of lithium-air batteries. These batteries hold a charge greater by a factor of nine compared to lithium-ion. In interpreting the batteries’ cycle life, Viswanathan expresses a distanced view. A traditional lithium-ion battery’s life is measured by its electrical discharge. In a lithium-air battery, discharge from the reaction of lithium and oxygen determines cycle life. But because air comprises more elements than just oxygen, Viswanathan wonders how many side reactions in the electricity delivery artificially boost the cycle life. Mitigating these side reactions should pave the way to developing long-lasting lithium-air batteries.

Large enhancement of response times of a protein conformational switch by computational design

  • By Leena Aggarwal
  • 16 April 2018

Lillian Chong and her colleagues have recently reported, in the Journal of Nature Communications, a computational design strategy in synergistic combination with biophysical experiments to rationally improve the response time of an engineered protein-based Ca2+-sensor in which the switching process occurs via mutually exclusive folding of two alternate frames. This strategy identifies mutations that increase switching rates by as much as 32-fold, achieving response times on the order of fast physiological Ca2+ fluctuations. This computational design strategy is general and may aid in optimizing the kinetics of other protein conformational switches.

Critical heat flux enhancement in pool boiling through increased rewetting on nanopillar array surfaces

  • By Leena Aggarwal
  • 12 April 2018

Boiling is a key heat transfer process for a variety of power generation and thermal management technologies. The enhancement in both the critical heat flux (CHF) and the critical temperature at CHF of the substrate and effectively increase the limit of boiling before the boiling crisis is triggered. By using only nanopillars with a systematic variation in height and well-defined geometrical dimensions, Paul W. Leu and colleagues have established a direct link between the enhancement in capillary force and the boiling performance of a substrate. This provides new insights about design of surface textures not only to amplify the heat flux, but also to achieve an enhancement in the temperature at critical heat flux. These results are published in Scientific Reports.

NSF's Big Ideas: Understanding the Rules of Life and The Quantum Leap

Speaker(s): 
Angela Wilson
Dates: 
Thursday, April 12, 2018 - 2:00pm to 3:00pm

Join Angela Wilson of NSF, Cynthia Burrows of the University of Utah, Theodore Goodson of the University of Michigan, and Glenn Ruskin of ACS for an introduction of two of the most impactful "Big Ideas" as well as an overview of this innovative NSF program that will advance prosperity, security, health, and well-being in the United States.

Learn more about : "Why Quantum entangled processes may play a role in our understanding of biological processes?"

Highly Efficient Strategy for Constructing New Types of Peptide Macrocycles

  • By Burcu Ozden
  • 10 April 2018

Peng Liu and his colleagues report a highly efficient and generally applicable strategy for constructing new types of peptide macrocycles using palladium-catalyzed intramolecular C(sp3)–H arylation reactions on their newly published paper in Nature Chemistry. 

This strategy provides a powerful tool to address the long-standing challenge of size- and composition-dependence in peptide macrocyclization, and generates novel peptide macrocycles with uniquely buttressed backbones and distinct loop-type three-dimensional structures.

Careers in Science: Science Policy and General Advice 

Speaker(s): 
Edward Dunlea
Dates: 
Tuesday, April 17, 2018 - 4:30pm to 5:30pm

Considering a career path outside academia? It can be confusing to figure out what else is out there, how to look for jobs, and how to decide what's right for you. Edward Dunlea, Special Assistant to the Dean of MCS, has been down this road and will offer some insights gleaned from his experiences in program management within the government, science policy both at a non-profit and within the private sector, and research administration in academia. His talk will focus on the field of science policy - what it is and how to find jobs - and he will also offer some general advice with an emphasis on careers outside of academia.

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