Research & Publications
Preventing Atrio-Esophageal Fistula During Atrial Fibrillation Ablation - Review of Techniques and Technologies
Tina Li, Akhil Parashar, Arun Sridhar
Publication In Progress
A medical review paper about techniques and technologies to help prevent atrio-esophageal fistula for people with atrial fibrillation.
Finite Element Study of Self-Deflections in Low Aspect Ratio Mirrors Subject to Kinematic Mounting Conditions
Tina Li, Nicole Hortizuela, Clinton Ng
A Zachary Trimble, Mark Chun
Publication In Progress
Continuation of my Summer 2015 research on "A Finite Element Study of the Self-Deflections in Large Mirrors Subject to Various Mounts." This paper looks into kinematic mounts for telescopes and examines the corroboration between analytical, numerical, and experimental self-deflections.
Ice-Induced Loading During Water Entry of Marine Vessels
Maurizio Porfiri
Mohammed Jalalisendi
New York University, Tandon School of Engineering
Summer 2016
In arctic environments, marine vessels should withstand impact loading from water-ice mixtures. This area of research is becoming more pressing as global warming is changing the polar landscape and is posing new scientific challenges on the mechanics of marine structures. The goal of this project is to establish an experimental scheme to measure ice-induced loading during water entry of wedges. As a stepping stone toward more realistic studies, water entry experiments are being performed by releasing neutrally buoyant solid bodies in the fluid to comprehend the effect of a solid phase during impact. Particle image velocimetry (PIV) and particle tracking velocimetry (PTV) are combined to experimentally characterize the water entry of a rigid wedge into a quiescent fluid in the presence of multiple solid bodies. The identification of the solid bodies during impact is being performed using PTV, while the velocity field is obtained through PIV. The pressure inside the disconnected fluid parcels is reconstructed through Navier-Stokes equations by utilizing a spatial eroding scheme that masks out the solid phase. Experimental results are expected to shed light on the effect of the solid phase on the pile-up evolution, flow physics, and hydrodynamic loading experienced by the wedge during water entry. These experiments will provide a basic understanding of the physics behind ice-impact loading.
A Finite Element Study of the Self-Deflections in Large Mirrors Subject to Various Mounts
Institute for Astronomy
Mark Chun and A Zachary Trimble
Summer 2015
The Institute for Astronomy is currently working on a project called ‘Imaka, which is a ground-layer adaptive optics (GLAO) system for the 2.2-meter telescope on Mauna Kea aiming for high resolution, high sensitivity, and a large field of view using relatively large mirrors. Due to the size and weight of large mirrors, gravity causes deflections in the mirror surface that will distort the output images. The design of a mount for large mirrors has to be carefully considered in order to support the mirror and reduce self-weight deflection. Mirror surface deflections were calculated using COMSOL, a finite element analysis (FEA) software, for various mounting designs. A simply-supported ring mount, a fixed ring mount, and a 3-point mount were modeled for a solid Borofloat33 glass mirror with a 400-mm diameter and 50-mm thickness. Model results were compared with analytical solutions to gain modeling skills and understanding of the software and the limitations of both the FEA and analytical models. For the ring mount, both simply-supported and fixed, there was a 3% difference between the FEA and analytical solutions (taking into account bending and shear stresses). As the aspect ratio of the mirror increases, bending stress dominates the deflection and shear stress becomes negligible for both the ring and 3-point mounts. Verification of basic mounts and understanding of FEA in COMSOL will facilitate the design and analysis of the more complex mounts that will be needed to support the ‘Imaka project’s mirrors.