10:10 am
Microsoft Teams

Abstract

Insects walk on water, snakes slither and fish swim. Animals move with astounding grace, speed and versatility, but how do they do it and what can we learn from them? From the incredible efficiency of the wet dog shake to colonies of ants building rafts out of their own bodies, David Hu shows how animals have adapted and evolved to traverse their environments, taking advantage of physical laws with results that are startling and ingenious.

His profile in the NY Times is here.

His book can be ordered here.

Bio

Dr. David Hu is a mechanical engineer who studies the interactions of animals with water. He has discovered how dogs shake dry, how insects walk on water, and how eyelashes protect the eyes from drying. Originally from Rockville, Maryland, he earned degrees in mathematics and mechanical engineering from M.I.T., and is now Professor of Mechanical Engineering and Biology and Adjunct Professor of Physics at Georgia Tech. He is a recipient of the National Science Foundation CAREER award for young scientists, the Ig Nobel Prize in Physics, and the Pineapple Science Prize (the Ig Nobel of China). His work has been featured in The Economist, The New York Times, Saturday Night Live, and Highlights for Children. He is the author of the book “How to walk on water and climb up walls,” published by Princeton University Press. He lives with his wife and two children in Atlanta, Georgia.

Lecture archive

10:10 am
322 Fryklund Hall

Abstract

The field of indoor air quality continually grows to accommodate novel pollutant sources as they are developed. Office equipment such as laser printers and photocopiers are known to emit volatile and particulate air pollutants, especially ultrafine aerosols. With the recent development and popularization of 3D printers, studies are needed to understand their potential emissions to indoor environments. 3D printing (also referred to as additive manufacturing or rapid prototyping) is a bottom-up process of creating a three-dimensional object layer by layer. As low-cost 3D printers are continually developed, personal-use units have become more popular in everyday indoor environments such as homes, offices, and schools. As shown in by studies published in recent years, heating and extrusion of polymeric materials generates ultrafine aerosols.

This talk will focus on an investigation of aerosols emissions from the operation of a 3D printer in a chamber study and also under real-use conditions. Specific objectives of this study were (1) to measure the time- and size-resolved emissions of ultrafine aerosols from the operation of a FDM 3D printer in a chamber study, (2) to gain insight into the chemistry of these aerosols through electron microscopy coupled with energy dispersive X-ray spectroscopy and Raman spectroscopy, and also (3) to perform comparative aerosol concentration measurements under real-use conditions in a variety of indoor environments.

Bio

Dr. Marina Vance is an Assistant Professor in Mechanical Engineering and Environmental Engineering at the University of Colorado Boulder. Her research is focused on applying engineering tools to better understand and minimize human exposure to novel environmental contaminants, especially nanoparticles or ultrafine aerosols, from everyday activities and the use of consumer products.

Lecture archive

10:10 am
322 Fryklund Hall

Abstract

This talk will focus on how a Lagrangian perspective on dynamics is used to capture the time evolution of complex systems, e.g., granular flows, fluid-solid interaction problems, etc. In this context, the aspects that turn out to be more challenging are tied to the handling of friction, contact, geometry, large deformations and numerical solution scaling. The talk will highlight modeling and numerical solution techniques developed to address several of these challenges. Our solution methodology contributions have been implemented in an open-source simulation platform called Chrono, which is available on GitHub and used by hundreds of individuals to analyze large multi-physics dynamics problems. The talk will touch on several applications tied to granular dynamics, 3D printing and additive manufacturing, robotics, and ground vehicle mobility.

Fluid-solid interaction simulation of a vehicle engaged in a fording maneuver. This scenario has been simulated both using an SPH-based solution of the Navier-Stokes equations of motion, and using a many-body dynamics approach in which the fluid dynamics was modeled using a collection of 1.4 million interacting rigid spheres.	Collection of chain-mail sheets of material as they are dropped in a 3D printing volume for a reverse engineering analysis used to figure out where each link of the yet-to-be-printed fabric lies.

Bio

Dan Negrut received his Mechanical Engineering Ph.D. in 1998 from the University of Iowa. He leads the Simulation-Based Engineering Lab at UW-Madison. The lab’s projects focus on high performance computing, computational dynamics, terramechanics, robotics, autonomous vehicles, and fluid-solid interaction problems. Dr. Negrut received in 2009 a National Science Foundation Career Award. Since 2010 he is an NVIDIA CUDA Fellow.

Lecture archive