University of Vermont

Engineering

2015 Richard Barrett Scholarships (in alphabetical order)

MICP: Microbially Induced Calcite Precipitation

Nick Bucci (Advisors: Drs. Ehsan Ghazanfari & Huijie Lu)

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Microbially Induced Calcite Precipitation (MICP) is a bio- geochemical process that produces calcium carbonate precipitation within a pours media matrix such as soil, or bedrock. Preventing contaminant migration via fracture networks in bedrock is extremely important for preserving our precious groundwater resources. MICP offers an attractive alternative method for permeability reduction to traditional grouting/cementation technologies due to its low viscosity reagents and low-pressure application technique. The effectiveness of MICP for rock fracture sealing and permeability reduction is being comprehensively evaluated for the distribution patterns of CaCO3 precipitation, and the resistance of precipitates to long-term persistent changes in temperature, pressure, and groundwater flows in subsurface environments. This research is exploring and developing the necessary laboratory methodologies, apparatuses, and procedures required to generate accurate data in support of MICP use in situ.

Biomimicry & Bamboo wind turbine blades

Sara Dorr(Advisor: Dr. Ting Tan)

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Carbon fiber composite materials are widely used for sporting equipment, aerospace and automotive engineering. These composites are valued for their high strength-to-weight ratio, but carbon fiber is expensive and has a high embodied energy. By mimicking the micro-structure found in the wall of the Moso Bamboo for the arrangement of carbon fibers in an engineered composite we hope to achieve high performance in strength and fracture resistance while reducing the quantity of costly carbon fibers. The structural fibers in the bamboo wall are functionally graded, with higher density near the stronger exterior surface and a linear decrease in fiber concentration moving inward. This graded pattern is speculated to contribute heavily to bamboo’s remarkable strength in resisting wind loads. The unidirectional carbon fibers in the functionally graded engineered composite were laid in three sections of increasing density from 10% to 40% of the total cross-sectional area. For control a composite was created with equal fiber distribution throughout and the same total number of fibers. Three of each type of composite specimen measuring ¼” * 1” * 2” were tested in compression and torsion and the fracture surfaces were examined. The functionally graded specimens consistently out performed the control in both strength and resistance to fracture. This engineered design will be used to create blades for a vertical axis wind turbine.

Pilot Reactor Development for Waste to Resource Recovery

Austin Grant(Advisors: Drs. Huijie Lu and Patrick Lee)

Polyhydroxyalkanoates (PHA) is a family of short-chain length polysters that are produced by microorganisms for intracellular energy storage. They are the precursors for biodegradable plastic, and are seen as a strong alternative to petro-chemical based plastics do to their properties and renewable production from otherwise un-utilized resources. In this study, the production potential of PHA is being explored using volatile fatty acid (VFA) profiles of three wastestreams from the greater Burlington, VT area: manure, wastewater sludge and compost. A 3L sequencing batch reactor was inoculated with the typical PHA- accumulating aerobe, Pseudomonas Putida, and was operated at 37 degree C with a solids retention time of 3 days and a feast-famine cycle of 12 hours. Synthetic mixtures of VFAs were created based on fermentation results of the three waste streams and fed to the SBR during the feast phase within each cycle. Cellular PHA content, PHA monomer structure, and its rheological properties are being investigated for the three synthetic VFA mixtures. By further comparing the properties to other commercial PHA polymers, the potential applications in manufacturing can be determined.

Tributary Water Quality Monitoring in the Lake Sunapee Watershed

Kira Kelley (Advisor: Dr. Donna Rizzo)

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Lake Sunapee, a Class A oligotrophic lake, provides drinking water for over 2000 people and supports the needs of a diverse range of aquatic species and local wildlife. As development in the watershed continues, the water quality, though still comparatively pristine, is showing rising levels of conductivity and phosphorous foreshadowing a decline in the Lake’s cleanliness and ability to provide for the physical and spiritual needs of its constituents. This project begun the process of quantifying sediment and phosphorus loading to Lake Sunapee from its tributaries.

Drones and Artificial Neural Networks: Sediment Budgeting of Vermont’s Rivers

Anna Waldron (Advisor: Dr. Donna Rizzo)

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Excess phosphorus and nutrients carried by sediment through river system networks are a primary source of water quality degradation of streams and lakes. This research aims to use computational data-driven techniques to improve the efficiency and cost of sediment budget evaluation and management. A variety of sediment data, currently collected from sensors in the Mad River and its tributaries in central Vermont, are used to develop and test these techniques. The recent explosion in sensor networks and data storage associated with hydrological monitoring has created a huge potential for automating data analysis and development of new analysis tools. In this work, we apply two new computation tools to the analysis of sediment-related data suspected of being a driver of harmful algae blooms in Lake Champlain. The primary sediment budgeting questions are: How much sediment is being transported? And, where is that sediment coming from?