SCHOOL OF MECHANICAL ENGINEERING SEMINAR
Monday January 15.1.2024 at 14:00

Wolfson Building of Mechanical Engineering, Room 206

Emergent complex functionality in microscopic machines and computational models

Itay Griniasty

Itay Griniasty is a Schmidt AI in science postdoc fellow at Cornell university

Systems composed of many interacting elements that collaboratively generate a function, such as meta-material robots, proteins, and neural networks are notoriously difficult to design.

Such systems elude traditional explicit design methodologies, which rely on composing individual components with specific subfunctions, such as cogs, springs and shafts, to achieve complex functionality. In part the problem stems from the fact that there are few principled approaches to the design of emergent functionality.  In this talk I will describe progress towards creating such paradigms for two canonical systems: I will first describe how bifurcations of the system dynamics can be used as an organizing principle for the design of functionality in protein like machines with magnetic interactions. I will then introduce a computational microscope that we have developed to analyze emergent functionality, and its application to machine learning. There we uncovered compelling evidence that the training of neural networks is inherently low dimensional, suggesting new paradigms for their design.

References

1. T. Yang et al. Bifurcation instructed design of multistate machines. Proceedings of the National Academy of Sciences, 120(34):e2300081120, 2023

2. J. Mao et al. The training process of many deep networks explores the same low-dimensional manifold. arXiv preprint arXiv:2305.01604, 2023.

3. R. Ramesh, et al. A picture of the space of typical learnable tasks. Proc. of International Conference of Machine Learning (ICML), 2023.

Short bio

Itay Griniasty is a Schmidt AI in science postdoc fellow at Cornell university, studying the design of microscopic and soft machines, non newtonian fluids and computational tools to analyze deep neural networks and multiphysics simulations.

Itay was trained as a mechanical designer in the technological unit in the IDF intelligence corps.

He studied mathematics and physics at the Hebrew university for his BSc, where his minor thesis led to a long collaboration on developing novel mathematical tools for the integration of non linear partial differential equations. He went on to a PhD in physics at the Weizmann institute, studying the propagation of waves in inhomogeneous media.

Itay has been awarded an Amirim merit scholarship for his BSc, an Azrieli excellence scholarhship for his PhD,  the Chaim Mida Prize for an excellent PhD student, a Fulbright postdoctoral fellowship (which he declined) and a Schmidt AI in science fellowship towards his postdoc

SCHOOL OF MECHANICAL ENGINEERING SEMINAR
Monday February 12.2.2024 at 14:00

Wolfson Building of Mechanical Engineering, Room 206

Towards an Environmentally Sustainable Future: Cool flames and Novel Combustion Technologies

Andy Thawko, Ph.D.

Postdoctoral Research Fellow, Mechanical and Aerospace Engineering Department,

Princeton University, USA

Email: andyth@princeton.edu

As global consensus on the critical need to mitigate greenhouse gas emissions and combat anthropogenic climate change grows, there is an urgent imperative to study the fundamentals of low-temperature combustion. This research is essential not only to improve the thermal efficiency of systems in the energy and transportation sectors but also to pave the way for the development of innovative technologies grounded in low-carbon and carbon-neutral fuels. While high-temperature combustion and hot flames have been extensively studied for decades, a new frontier in combustion science has emerged—low-temperature combustion and cool flames, with only a few research groups worldwide actively investigating this field. Our research on high-pressure cool flames led to the discovery of a new pressure-dependent relation for the cool flame heat release rate. This finding, distinct from the well-established pressure-independent relation of hot flames, emphasizes the profound influence of pressure on cool flames. Furthermore, I will introduce the radical index theory for high-pressure cool flames, offering a quantitative measure of the low-temperature reactivity of fuels. This measure serves to assess the suitability of existing or newly synthesized fuels for advanced propulsion technologies based on low-temperature combustion. Finally, I will present a new understanding of the kinetic enhancement effect in the deflagration to detonation transition (DDT), allowing acceleration of the shock-ignition coupling and the detonation transition. The insights gained from this research are significant to further develop new methods based on ignition enhancers such as plasma-assisted DDT because DDT acceleration is crucial for eliminating detonation stability and reducing heat losses, leading to improved combustion efficiency and enhanced thermodynamic cycles by up to 30%. This seminar aims to shed light on the pivotal role of low-temperature combustion in the ongoing global effort to address climate change. Through our research, we contribute valuable insights that have implications for both fundamental combustion science and the practical development of environmentally sustainable technologies.

Andy Thawko has been Postdoctoral Research Fellow at Princeton University since 2022. His research interests include thermofluids and combustion science with a focus on low-temperature combustion, energy decarbonization, and kinetic enhancement of processes. Andy completed his Ph.D. in 2021 at the Grand Technion Energy Program, conducting research in the Faculty of Mechanical Engineering. Prior to this, he earned his M.E. in Energy Engineering in 2013, and his B.S. in Mechanical Engineering in 2009, both from the Technion.