Faculty Research Talks - Fall 2020
Talks will be held at 2:30PM on every other Monday (M) at 2:30PM via WebEx unless otherwise noted. Please see more information below:
Talks will be held at 2:30PM on every other Monday (M) at 2:30PM via WebEx unless otherwise noted. Please see more information below:
Date | Speaker, Title, and Abstract |
---|---|
September 21 |
Professor Yuan-Nan Young Where is the Math in Fluid Mechanics and Biology? Life on earth happens in fluid, and after millions of years of evolution we humans are organisms that (1) consist of mostly water, (2) rely on water for food and basic survival, and (3) I would argue that human beings need to know fluid mechanics to advance as a species. Trained as a theoretical physicist in fluid mechanics and dynamics, I want to take this opportunity to show you some interesting math in fluid mechanics and biology from the viewpoints of applied math and physics. |
October 5 |
Professor Cyrill Muratov Magnetic Skyrmions in the Conformal Limit We characterize skyrmions in ultrathin ferromagnetic films as local minimizers of a reduced micromagnetic energy appropriate for quasi two-dimensional materials with perpendicular magnetic anisotropy and interfacial Dzyaloshinskii-Moriya interaction. The minimization is carried out in a suitable class of two-dimensional magnetization configurations that prevents the energy from going to negative infinity, while not imposing any restrictions on the spatial scale of the configuration. We first demonstrate existence of minimizers for an explicit range of the model parameters when the energy is dominated by the exchange energy. We then investigate the conformal limit, in which only the exchange energy survives and identify the asymptotic profiles of the skyrmions as degree 1 harmonic maps from the plane to the sphere, together with their radii, angles and energies. A byproduct of our analysis is a quantitative rigidity result for degree ±1 harmonic maps from the two-dimensional sphere to itself. |
October 19 |
Professor Enkeleida Lushi Active and Driven Particles at the Micro-Scale Recent advances in chemistry and engineering have made possible the synthesis of micro-scale particles that can move and rotate. These active particles can be rendered motile by a surface catalysis with a chemical dispersed in the immersing medium, or can be driven by external stimuli such as light, acoustics or electromagnetic fields. I will discuss a few examples of such "micro-robots" and the recent efforts made to control and direct their individual and collective behavior. In particular we will focus on how Mathematics and Scientific Computing can help in understanding the dynamics seen in experiments. The two types of active particles we'll discuss in detail are bi-metallic swimmers and driven spinning particles. In both cases, we'll explain the full models, any simplified models and what they can elucidate, as well as full simulations. Lastly, I will discuss our recent work where experiments, analysis and simulations converged to understand new phenomena, and will highlight some new problems. |
November 2 |
Cancelled |
November 16 |
Professor Amitabha Bose Towards a Neural and Mathematical Understanding of How We Generate and Keep a Musical Beat While many people say they have no rhythm, most humans when listening to music can easily discern and move to a beat. On the other hand, many of us are not so adept at actually generating and maintaining a constant beat over a period of time. Demonstrating a beat is a very complicated task. Among other things, it involves the ability of our brains to estimate time intervals and to make physical movements, for example hitting a drum, in coordination with the time estimates that we make. How our brain and body solves this problem is an open and active area of research. In this talk, I will discuss a new mathematical model for a beat generator, which is defined here as a group of neurons that can learn to keep a constant beat across a range of frequencies relevant to music. The goal of the talk is not just to introduce a new way of thinking of beat generation, but also to raise a series of questions about the nature of time and the role of perception in our ability to make decisions. |
November 30 |
Professor Lou Kondic Soft Matter Systems: Simulations, Modeling, Big data, Networks, Topology
This project focuses on modeling soft matter systems using discrete element simulations, to be carried out at NJIT, in collaboration with further development of algebraic topology methods with colleagues at Rutgers.
A significant part of the research in applied fields of science and engineering focuses on the systems built up from discrete objects. This includes the systems relevant to materials science, such as dry and wet granular systems, but also many other soft-matter systems such as foams, colloids, and liquid crystals. There is also an increasingly relevant and active field of active matter where the systems of interest are built out of particles governed by some type of internal forces, such as bacteria and similar. Lack of continuum-based models for many of the listed systems requires carrying out discrete element simulations that focus on modeling particle-particle interactions. Due to increased computational resources, current simulations are able to provide realistic description of the experimental systems and can often be used with predictive power. However, the separation of spatial and temporal scales describing particles and their interactions, and of those describing me-so- or macro-scales that are of interest when considering properties of a system as a whole, leads to increasingly large and essentially unmanageable amount of data. This project focuses on development of a technique that allows to reach deeper understanding of the dynamical properties of the considered complex systems by extracting required information from these large data sets. The component of the research that is carried out at NJIT consists of development of models and simulations of the systems built of a large number of particles interacting by attractive and repulsive potentials, in two and three spatial dimensions. The research will be carried out in close collaboration with the computational topology groups at Rutgers and U. Oklahoma. The project also includes international collaboration led by K. Mischaikow, as well as with the experimental group at Duke led with L. Pugnaloni and his group at La Plata, Argentina. As an outcome of the proposed project, we will develop much better understanding of the dynamical properties of the considered systems. http://cfsm.njit.edu/publications/manuscripts/gameiro2020interaction.pdf http://cfsm.njit.edu/publications/manuscripts/takahashi2018granular.pdf http://cfsm.njit.edu/publications/manuscripts/clark2015nonlinear.pdf |
Updated: November 16, 2020