Current Research
Thermal Inactivation of Pathogens through Electromagnetic Heating: Pathogens, such as influenza and coronaviruses, are transmitted in part by way of aerosolized droplets on which they reside. These droplets are small enough that the turbulent motion within the air can offset gravitational effects for relatively long periods of time. This research program looks at the effects of ohmic heating where electromagnetic radiation is absorbed by droplets, elevating their temperature, and potentially inactivating virions on the droplet. A recent paper shows the potential of this approach over a range of pathogens, noting that there are several alternative pathways not investigated here by which electromagnetic energy can lead to bacterial or viral inactivation.
Collaborators: Dr. Brad Hoff (AFRL, Kirtland AFB), Dr. Zane Cohick (AFRL, Kirtland AFB), Dr. John Luginsland (AFOSR), Dr. Robert Thomas (AFRL, JBSA Fort Sam Houston). Previous students include Kai Chhoeuk (BS, Mathematical Sciences, WPI)
Multiscale Modeling in Beamed Energy Harnessing Applications: A large number of space-based applications exist for the transmission of electromagnetic energy to a system some distance away. For example,work is being done to use a satellite to collect and convert solar energy into microwaves that will then be beamed to earth to help contribute to US energy production. From the other direction, energy generated on earth could be transmitted to satellites to add to the power being generated by solar panels. Along those lines, beamed energy propulsion has also been proposed as a method of improving current rocket propulsion capabilities. A common thread in these technologies is the conversion of electromagnetic energy into a mechanically useful form. The overall goal of this work is to determine the viability of a microwave heat exchanger, where microwave energy is harnessed as the power source by an absorbing material through which a coolant is heated, through computational and mathematical modeling. Funded by AFOSR FA9550-15-0476, AFOSR FA9550-18-1-0528.
Collaborators: Prof. V.V. Yakovlev (Mathematical Sciences, WPI), Dr. Brad Hoff (AFRL, Kirtland AFB), Dr. Zane Cohick (AFRL Kirtland AFB). Previous students include J.M. Gaone (PhD, Mathematical Sciences, WPI), Ajit Mohekar (PhD , Mechanical Engineering, WPI), Nicolas Porter (BS, Mathematical Sciences, WPI), Kiersten Grieco (BS, Mathematics, Kings University), Ye Chen (BS, Mathematical Sciences, WPI), J. Jorgensen (BS, Mathematical Sciences, WPI) , Darcy Milligan (BS, Mechanical Engineering, WPI) and Nathan Willemsen (Data Science, WPI).
Fundamental Understanding of Rapid Air Drying in Paper Tissues: In the fabrication of tissues, water drying is an energy-intensive and rate-limiting step. The drying process which transforms the pulp into a dry tissue incorporates many potential physical mechanisms, including evaporation, diffusion, capillary forces, elasticity and volume expansion to name a few. Water interactions with wood fiber at the micro-scale level need to be described so that additional step-change speed and quality improvements can be made in the process. We want to understand the underlying reasons for low mobility of water to the surface when the sheets are at low moisture content (below 0.5 g/g). The ability to conserve energy in particular and water in that process are also important goals for the research program. Funded through the Center for Advanced Research in Drying
Collaborators: Prof. J. Yagoobi (Mechanical Engineering, WPI), Dr. Francisco Duran-Olivencia (Postdoc, Mechanical Engineering), Menqiao Yang and Zahra Noori (PhD Students, Mechanical Engineering, WPI).
Geothermal Energy Harvesting: In this research program, we focus on the promise of environmentally friendly, low-cost energy harnessing for heating and cooling of homes and buildings through the use of ground-source heat pumps (GSHP). The installation costs for current residential geothermal systems are currently cost-prohibitive, with a typical return-time on investment on the order of 8-10 years. A significant portion of this cost is in the installation of large networks of piping to harness the geothermal energy. Our focus in this research program is to develop mathematical models to quantify how the length of the piping is related to the operational parameters of the system. Additional research focuses on the use of aquifers for energy storage applications. Funded through two NSF supported Research Experiences for Undergraduates (REU) projects, (DMS- 1004795 and DMS-1263127).
Collaborators: Prof. T. Baumann (Geochemistry, TU-Munich), Prof. Suzanne Weekes (Mathematical Sciences, WPI),
Thermocapillary flows in thin fluid films, jets, and sheets: In this research program, we focus on the interfacial dynamcs of incompressible thin fluid films and jets in a variety of engineering applications. For example, ink-jet printers have become a common and economical standard for producing high-quality printed text and graphics. These printers typically employ several different jets simultaneously, each made up of a different color of ink; arbitrary colors can therefore be generated by mixing the output of the jets in different proportions. Since only one drop size is typically generated, the efficient control of drop formation is an inherent requirement in the overall performance of the system. The limitation on resolution of these devices is down to the reliable control of the smallest drop size while the printing rate depends on the ability to control the break-up phenomena both spatially and in time. For applications like this, we take advantage of the small aspect ratios of the films to asymptotically derive simpler systems of equations that capture the leading-order interfacial dynamics that conserves momentum and energy.
Collaborators: Prof. M. Bowen (Mathematics, Waseda University, Tokyo), Thomas deRito (BS, Mathematical Sciences, WPI)
Effective models for liquid-cooled electronics systems: We are interested in how the microscale geometry and compositional and conductivity gradients in coolants affect net heat transport in liquid-cooled electronics applications. Rates of heat transfer from semiconductor devices are a significant limitation in the processing capabilities of these devices. Liquid cooling has shown promise in improving the rates of heat transport in these devices. Although the experimental capability to design and fabricate specific microstructures in materials has advanced significantly in the past few decades, a description of their effective thermal behavior on the microscale has not kept pace. Current modeling of these multi-physics systems has focused on direct computational approaches, bu they are limited due to the need to resolve the finest length-scales (microns) over the length scale of the full application (centimeters). We employ an asymptotic approach to formulate effective transport equations that capture the dominant net fine-scale physical effects on the application length scale. This modeling approach provides an efficient means to determine how competition of different microscale effects can change macroscale behavior. Funded by AFOSR FA9550-11-1-0197.
Collaborators: Prof. B. Vernsecu (Mathematics, WPI), Prof. S. Jimenez-Bolzanos (Mathematics, Colgate University)