2017 Rasmussen Summer Research Projects
For the summer of 2017, four recipients (HMC students and faculty) were awarded support from the Rasmussen Summer Research Fund. You can view the project abstracts, proposals, and final reports below.
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Characterizing Novel Oxidant Precursors for Simulating SOA Formation in the Potential Aerosol Mass Oxidative Flow Reactor – Jason Casar (HMC-’18)
Abstract: With average global temperatures climbing at a rate of 0.15-0.2°C per year since 1975, the ability to monitor climate-altering pollutants has become increasingly important.1 Anthropogenic climate change is attributed to the buildup of several key gas phase compounds, organic aerosols, and soot. Understanding the extent to which earth’s climate will change in the coming years is contingent upon our ability to accurately measure the size, concentration, chemical composition, and optical properties of these compounds. Aerodyne Research Inc. devotes itself to building and testing instrumentation and software that helps professionals understand this kind of atmospheric chemistry. They also deploy these devices in field campaigns and laboratory simulations. If funded, I would be involved in characterizing instrumentation to test for Secondary Organic Aerosols and their climate altering impacts, as well as processing and interpreting data. This work would be closely related to the research I conducted over the past two summers in Professor Hawkins’ lab. After completing this work I hope to further the capabilities of atmospheric sampling technologies, and gain practical insight into the intersection of atmospheric chemistry, electrical engineering and signal processing.
Aerosal Particle Concentration Mapping using Semi-Autonomous Vehicles – Gabriel Quiroz (HMC-’19), Jared Brauner, Lelia Hawkins (Chemistry), Christopher Clark (Engineering)
Abstract: This paper presents an approach to mapping aerosol particle concentrations in urban areas using semiautonomous vehicles that are constrained to driving on existing roadways. Particle concentration maps were constructed by discretizing the geographic area of interest into uniformly spaced cells, and associating a particle concentration estimate and variance with each one of the cells. These particle concentration estimates and variances are updated in real time with a set of 1D Kalman Filters, which fuse aerosol particle measurements obtained from a Mixing Condensation Particle Counter (MCPC) mounted on a mobile vehicle. A novel contribution of this work includes a real-time vehicular path planner that constructs time-constrained routes that are optimal with respect to a cost function. The proposed cost function optimizes two objectives: (1) sampling in unmapped areas and (2) sampling in areas of high particle concentration. To validate the system, a time series of particle concentration maps of Claremont, CA were constructed using actual vehicle deployments. The deployments confirm that the system can capture temporal variability with a resolution of hours and spatial variability on the order of 10s of meters.
An Ultrasound Phased Array for Underwater Power Transfer – Yashas Hegde (HMC-’18), Bradley Phelps (HMC-’19), Hamza Khan (HMC-’18), Matthew Spencer (Engineering)
Abstract: Technology for observing and tracking aquatic species is well-studied, but it is still limited by the size, recoverability and battery life of underwater tracking tags. This work describes a method of bypassing these limitations by establishing an acoustic communication link between a beam-steering phased array and a passive energy-harvesting tag. Passive tags can theoretically be used for the entire lifetime of the specimen of interest and they may be smaller than powered transmitting tags because of reduced power storage needs. This enables longer term tracking studies and tracking studies of smaller species of fish. A fully functioning beam-steering array has been demonstrated and characterized at distances up to three meters. We have also created a prototype receiving tag that can harvest energy and receive transmitted location information. These devices are the first building blocks of a power and two-way communication link.
Reductive Activation of Bio-Inspired Nickel Compounds for Dechlorination Reactions – Christopher Ye (HMC-’19), Katherine Van Heuvelen (Chemistry)
Abstract: The chlorinated hydrocarbons perchloroethylene (PCE, C2Cl4) and trichloroethylene (TCE, C2HCl3) are widely used in industrial processes including dry cleaning and metal degreasing, but these complexes have recently been identified as carcinogens. Industrial runoff containing PCE and TCE is known to pollute soil and groundwater across the United States. A small number of enzymes convert PCE and TCE to non-toxic ethylene under environmentally friendly conditions using earth-abundant materials, and this reaction is called dehalogenation. Chemists know the geometric structure of these enzymes; the reductive dehalogenases use the cobalt-containing cobalamin cofactor (also in Vitamin B12), and methyl-coenzyme M (MCR) uses the nickel-containing cofactor F430 to conduct this chemistry. But chemists do not yet understand the fundamental chemistry that governs this reactivity, which prevents us from rationally designing biologically inspired, environmentally friendly catalysts to remediate PCE and TCE. In the summer of 2017, I propose to:
- Synthesize a family of four nickel- and cobalt- containing model compounds designed to reproduce key features of the enzymes that catalyze dehalogenation reactions.
- Evaluate the reactivity of these compounds toward the chlorinated hydrocarbons PCE and TCE using gas chromatography-mass spectrometry and characterize reaction intermediates and products using UV-visible spectroscopy.
- Investigate possible reaction mechanisms using computational chemistry as implemented on the XSEDE supercomputer.
- Combine insights from aims 1 – 3 to elucidate the reaction mechanism, ultimately applying a detailed understanding of the fundamental chemistry underlying dehalogenation to the rational design of an improved catalytic system to treat chlorinated pollutants before they enter the water supply.