Pollutant removal in soils, for example through bioremediation, has long been touted as a potential solution to anthropogenically induced climate change impacts by improving soil health. Yet, these efforts are not often implemented at large-scales, and when they are, pollutant run-off and greenhouse gas (GHG) emissions outpace existing attempts. As atmospheric GHGs continue to rise outside of the safe operating space, it becomes crucial to search for avenues that offset them. Soils have huge potential to store carbon long-term, but when soils are polluted, it impacts their carbon storage capacity. It is clear we are in dire need of sustainable solutions that remove soil pollutants, increase soil carbon storage, and promote a healthy soil community. The physiological pathways that exist in plants, bacteria, and fungi are often interlinked, and evidence shows that certain interactions can ultimately lead to the storage of carbon in soils. Therefore, we hypothesize that the delivery of synergistic bacteria, fungi, and biochar via hydrogel beads will promote plant and soil communities’ ability to increase soil nutrients for plant uptake while removing pollutants and facilitating carbon storage. Preliminary data from our study, in which we applied mixed fungal-bacterial-char hydrogel beads to polluted soils growing Sorghum bicolor or Helianthus anuus, demonstrated that our novel biotechnology has potential to decrease heavy metal concentrations and toxic compounds. Additionally, we have begun analyzing the carbon storage potential through Loss on Ignition methodology, which provides measures of soil organic and inorganic carbon. Preliminary measurements show that soils that received hydrogels with an encased fungal-microbial-char consortia also increase soil carbon. These studies will not only inform the efficacy of hydrogel-delivered biofertilizers in terms of plant growth and productivity, but will also build a foundation for future research into how to promote soil health to mitigate the negative impacts of climate change.

Current concentrations of carbon dioxide are 420 ppm, a 50% increase since the industrial revolution. Nitrous oxide (N₂O) concentration has increased by 18% since the industrial revolution and is currently 319 ppb. This slight increase may not appear alarming, but since nitrous oxide traps 300 times more heat than carbon dioxide, lowering emissions of this greenhouse gas will help stabilize the climate. One major source and sink of N₂O is production and reduction by microbes, respectively, which have been perturbed by anthropogenic increases of nitrogen. Novel microbes found in low pH (3-6) subsurface sites in Tennessee have been shown to respire N₂O, reducing it to N₂ using both Clade I or II nitrous oxide reductases. Microbes that can reduce N₂O at such low pHs (below 5) are rare but could be beneficial as a sink for nitrous oxide. One such strain is a novel Bacteroidetes that encodes a Clade II nitrous oxide reductase and was provisionally named strain S13. In my experiment, I aim to better understand the metabolic processes of this strain and identify the optimal temperature for growth, using xylose, a 5-carbon sugar, as the carbon source. S13 was then grown in an electron acceptor (N₂O) limiting environment, electron donor (xylose) limiting environment, and fermentative conditions. After the microbes completed their growth, the gas and metabolite concentrations were measured using Gas Chromatography and High-Performance Liquid Chromatography. When grown on xylose, the products produced were hydrogen gas, succinate, and acetate. Optical density of these tubes was measured over the course of their growth to determine growth rates and maximum yield (optical density). This was done at 6 temperatures: 15°C, 20°C, 25°C, 30°C, 35°C, and 40°C. These data indicated that S13’s optimal temperature for growth was 25°C. This information could be utilized in future bioremediation and nitrous oxide control efforts.

The Strand Lab Benzene Team quanitified the removal of benzene by a genetically modified plant (2E1 pothos ivy) under concentrations similar to home environments. The objective is to make this houseplant available to the public and develop a practical home biofilter that uses a genetically modified (GM) houseplant. The development of a genetically modified pothos ivy with the 2E1 gene provides means to degrade volatile organic compounds (VOC), for example, benzene. My partner developed extraction procedures while I developed the analysis procedures for influent and effluent samples concentrating benzene so that analysis could be done by injection of the concentrated extracts on gas chromatography with flame ionization detection (GC-FID). I created calibration curves with external standards to help quantify the concentration of benzene within a sample. GC-FID was used to measure benzene area peaks for both the influent and effluent samples from which benzene concentrations in conjunction with the standard curves could be calculated. Our findings reveal a 65% removal of benzene by the A9 transformant of pothos ivy containing the cytochrome P450 2E1. The wild-type plant showed no significant benzene removal. The development of this GM houseplant offers a promising solution for indoor air purification, potentially mitigating health risks associated with the exposure of benzene and other VOCs. Furthermore, the potential commercialization of GM houseplants could influence the biotech industry to expand the application of biofilters beyond the home environment such as office spaces, schools, and hospitals. 

Ferrate is an effective technology for water treatment applications because of its capabilities as an oxidant, coagulant, and disinfectant. Furthermore, ferrate is an environmentally benign chemical derived from a ubiquitous mineral on the Earth’s surface. However, ferrate rapid reduction to ferric species reduces its oxidation capacity. Ferrate-coated sand has been proposed as a better deployable method for ferrate in water treatment applications. Sand has a high composition (>80%) of silica (SiO₂) which has been demonstrated to stabilize ferrate reactivity and increase its oxidation capacity. A previous study on the treatment of phenol, a common surface water contaminant, showed that ferrate-coated sand was better at degrading phenol than ferrate only (in the absence of sand). However, the study was conducted in pure water matrices. Here, we are evaluating the oxidation of phenol by ferrate-coated sand in the presence of effluent organic matter and trace metals (i.e. copper). Organic matter is ubiquitous in the environment and can impact contaminant remediation efficiency. Studies have detected trace metals in surface waters which can pose environmental and health risks. Through batch tests, we observed that effluent organic matter hinders the stability of the ferrate-coated media and reduces its oxidation capacity. The results of this study will provide information about the ferrate-coated sand reactivity and capacity for the treatment of complex water matrices.

6PPD-quinone (6PPDQ), a transformation product of an anti-oxidant used in tire manufacturing, was recently identified as the causal agent of acute mortality in coho salmon. Abrasion on tires by road surfaces create tire wear particles (TWPs). Both TWPs and the accumulation of waste tires pose risks of leaching 6PPDQ into stormwater runoff. Crumb rubbers, which are manufactured to reduce landfill tire waste and applied in turf infills, may also leach 6PPDQ. My research aims to determine the conditions at which crumb rubber can be pyrolyzed to prevent 6PPDQ leaching from tire recycling options. If pyrolysis successfully removes 6PPDQ from crumb rubber, then the resulting material can be applied as an absorbent tire char to remove contaminants from water. Waste tire crumb rubber samples were pyrolyzed in a tube furnace under nitrogen flow for 90 minutes at a range of different temperatures. Methanol-based solvent extraction was used to extract the remaining 6PPDQ from the pyrolyzed samples and diluted until suitable for liquid chromatography-tandem mass spectrometry (LC/MS/MS) analysis. It is observed that as the pyrolysis temperature increases, the mass of 6PPDQ leached from pyrolyzed crumb rubber decreases. The results of this study allow us to understand the limitations of pyrolyzing tire rubber to develop activated carbon. To further investigate the feasibility of waste tire activated carbon, a chemical activation step will be added in pyrolysis to better replicate the creation of activated carbon.

Data show the one-sided diverging diamond interchange (OSDDI), which I developed, can substantially outperform both the conventional diamond interchange (CDI) and diverging diamond interchange (DDI) in traffic operations. The OSDDI, CDI, and DDI are all forms of the diamond interchange—the most common type of freeway-to-arterial link in the United States. The CDI and DDI are widely used in the United States. While my preliminary analyses give promise that the OSDDI is not less safe than the CDI, its overall safety performance has yet to be comprehensively explored. According to the Federal Highway Administration (FHWA), over half of all injury or fatal crashes occur at an intersection. This statistic makes it important to analyze the safety performance of the OSDDI in greater detail. I fill this research gap in this study by analyzing the vehicular and pedestrian safety performance of the OSDDI relative to the CDI and DDI. I use Verkehr In Städten—SIMulationsmodell (VISSIM), a microscopic traffic simulation software, to simulate how each design performs in multiple traffic demand scenarios. I then use the Surrogate Safety Assessment Model (SSAM), developed by FHWA, to predict the safety performance of each design using trajectory data from VISSIM and traffic conflict analysis. Finally, I conduct statistical tests to find if the OSDDI is statistically significantly safer than the CDI and DDI. I expect the OSDDI to be statistically significantly safer than the CDI and comparable to the DDI for both vehicles and pedestrians. The results of this study may encourage transportation agencies to consider the OSDDI as an alternative diamond interchange design to improve safety and mobility for people walking, biking, and driving.

Music box, invented in the 18th century, has been reimagined by the design industry as an interactive and assembly-friendly toy product. This innovation serves as a seamless integration of a nostalgic object with the demands of contemporary life experience. However, such "packaged in box" products face significant customization limitations from the user's perspective, including fixed music options and predetermined model parts. Given the burgeoning resources in digital modeling and rapid prototyping, the product design process is poised to advance into the computational fabrication era. Our interdisciplinary student team has been re-envisioning the structure and functionality of our music box through programming, Computer-Aided Design, and 3D printing. Specifically, our team developed the three parts to construct the music box: a digitally constructed spinner, where its 3D model was transformed from MIDI file, allowing for a wide range of musical expression; an adaptable mechanical connection structure for spinners of various sizes; and an innovative mechanism that triggers keyboard notes without direct spinner contact, maintaining sound quality and reducing wear out plastic parts. These designs enable customizable features, easy part replacement, and solve sound and durability issues associated with plastic components. With the goal of creating a customizable product in mind, each member of our team contributed to and took responsibility for the components in which they specialized. The purpose that our music box serves does not stagnate as a mere music playback machine; rather, its functionality expands across various aspects. Our innovation is not only ideal for those who wish to integrate artistic perspectives with functional machine prototyping and customize their songs , but also boosts creativity for individuals and institutions, enabling further projects that could benefit early education and future engineering workshops.

Half of the earth's photosynthetic activity occurs in the ocean. However, marine ecosystems generally have lower rates of carbon sequestration when compared to terrestrial ones. This is an opportunity to enable large scale carbon sequestration. The waters of the open ocean are nutrient deficient and can have low primary productivity. Supplying the limiting nutrients can theoretically enable rapid growth of photosynthetic cells but this growth must be contained or it will be lost to the ocean. By preparing these missing nutrients in hydrogels with efficient photosynthetic consortia, the growth process and inputs can be contained and the biomass harvested. The Winkler Lab is using this method to develope biological systems for carbon sequestration. I am researching the efficiency of microalgae and cyanobacteria consortia in seawater with native microbes. I aim to form cultures of photosynthetic marine microbes by inoculating hydrogels containing chlorella sp. in seawater samples. The objective is to optimize squestration with naturally occurring microbial consortia. Through multiple trials I have identified a mix of microbes and macroalgae cultured from the Puget Sound that exhibits rapid biomass production. Data is collected via microscopy, imaging and by measuring chemical oxygen demand and chlorophyll content. My aim is to compare this wild microbial mix to the Winkler lab's established mixes of cyanobacteria and microalgae and determine which is more effective in fixing carbon. Expected results will demonstrate this wild culture more efficient in low nutrient environments than the lab culture. Success in this project could help refine commercializable methods to remove atmospheric carbon dioxide and fight climate change.