Undergraduate Research Day Projects
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Organized by the University of Houston Office of Undergraduate Research and Major Awards, Undergraduate Research Day is an annual event showcasing exceptional scholarship undertaken by the UH undergraduate community.
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Browsing Undergraduate Research Day Projects by Department "Chemical and Biomolecular Engineering, William A. Brookshire Department of"
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Item A computational investigation of folding free energy surfaces and structural characterization of Staphylococcal Protein A(2023-04-13) Nguyen, Minh NgocInvasive plants disrupt native ecosystems and decrease native plant diversity. Under strong selection pressure, native plants sometimes adapt to better compete with an invasive species. My research investigates two variants of the annual forb Coreopsis that co-occur with the invasive forb Verbena brasiliensis. The objective of my research is to answer three questions: (1) Is an observed phenotypic variant Coreopsis more competitive than the wild type C. tinctoria? (2) If so, what traits potentially make it more competitive?, (3) Is it an adapted variety of C. tinctoria or a related species? Whether or not it is a separate species, the existence of a more competitive variant may provide an effective replacement for the wild-type C. tinctoria in native restoration projects within the range of V. brasiliensis. Results suggest that the invasive V. brasiliensis does not significantly suppress the biomass of the phenotypic variant C. tinctoria as much as that of the wild-type C. tinctoria. Furthermore, the variant produces significantly more flowers than the wild type suggesting it would be more competitive with the invasive plant than the wild type. The stark difference in growth habits between the two varieties of C. tinctoria suggests the variant may be a closely related species that converge in appearance at maturity.Item Chabazite Zeolite Synthesis Using Inorganic Structure-Directing Agents(2023-04-13) Varghese, NathanZeolites are aluminosilicate crystals with nanopores commonly used as adsorbents and catalysts in industrial applications. My zeolite framework of interest is chabazite (CHA), which is heavily used in industry to break down NOx emissions. In industry, most of this CHA is produced using organic structure-directing agents, which can produce CHA at high yields but is extremely expensive to use, is very dangerous to the environment, and cannot be recovered after synthesis due to calcination. In previous studies, inorganic structure-directing agents like potassium cations have been used to synthesize CHA instead of the traditionally used organic compounds, but this approach often yields CHA in a mixture of other different zeolite frameworks. Another approach to this issue is to use a mixture of inorganic structure-directing agents like lithium, sodium, and potassium cations to help isolate fully crystalline CHA. In previous studies led by Dr. Rimer and Dr. Mintova, combinations of potassium and strontium cations, as well as combinations of sodium, potassium, and cesium cations, have been used to synthesize relatively pure CHA yields. Over the Fall 2022 semester, I have been working with the Rimer group at the University of Houston to synthesize CHA at high purities and yields and across various temperatures and time ranges using multiple combinations of lithium, sodium, and potassium cations.Item Characterizing Z-rings in Persister Cells(2023-04-13) Ofomaja, MiraclePersister cells are a subpopulation of bacterial cells that survive antibiotic treatments without specialized mechanisms by temporarily entering a dormant state [1]. Because they proliferate into new bacterial populations after the antibiotic stress is removed, persister cells are associated with recalcitrant infections and antibiotic failure [1,2]. Hence, persisters are a significant public health challenge. It is also important to note that persister cell progeny consists of persisters and cells susceptible to the same antibiotics as the non-persister cells in the original population. Thus, persisters are a transient phenotype. This research project studies Z-rings, physiological structures in bacterial cells that form when the cells are about to divide into daughter cells. Z rings represent a potential biomarker for persister cells because there seems to be a correlation between their formation and persister resuscitation [3]. Specifically, this project aims to investigate this correlation in persister cells formed after ampicillin and fosfomycin treatments. If Z-rings are fundamental to persister survival, researchers can develop clinical therapies that target the Z-rings to sterilize persister cells and reduce recalcitrant bacterial infections. References: 1. Lewis, K., 2010. Persister cells. Annual review of microbiology, 64, pp.357-372. 2. Gollan, B., Grabe, G., Michaux, C. and Helaine, S., 2019. Bacterial persisters and infection: past, present, and progressing. Annual review of microbiology, 73, pp.359-385. 3. Mohiuddin, S.G., Massahi, A. and Orman, M.A., 2022. Lon Deletion Impairs Persister Cell Resuscitation in Escherichia coli. Mbio, 13(1), pp.e02187-21.Item CO and NO Co-Oxidation in PdCu Catalysts(2022-04-14) Freeman, CaseyNewly developed diesel engines operate at lower temperatures and can simultaneously reduce NOx, particulate matter, and fuel consumption. However, typical catalytic converters use platinum-palladium alloys, which aren't active enough to meet EPA emission regulations at low temperatures due to the inhibition caused by the competitive adsorption between CO and NO. Thus, excess fuel must be burned in the engine to increase the exhaust temperature before entering the DOC. Since CO binds to the active sites more strongly than NO, the Pt-Pd catalyst bed must also be long enough for sufficient NO conversion. Finding a catalyst that co-oxidizes CO and NO at low temperatures with minimal inhibition effects will maximize fuel economy and lower the required costly precious metal loading for the DOC. Using density functional theory (DFT) and descriptor-based microkinetic modeling, alloys of coinage metals (copper, gold, and silver) with at least one oxophilic component were identified as potential candidates. Further computational screening of Pd and Pt alloyed with Cu or Ag was used to determine PdCu alloys as the most promising for inhibition-free, low-temperature CO oxidation in the presence of NO. By flowing gasses through a bench-scale reactor, we evaluated the performance of the PdCu, PdPt, and PdCu+PdPt alloys. The findings indicate the PdCu catalyst has the potential to improve PdPt at reduced temperatures.Item Computational Study of CO2 Capture Using MIL-100 (Cr)(2023-04-13) Fleming, KevinMetal-organic frameworks (MOFs) are porous organometallic compounds that are of high interest to many researchers due to their capability to trap industrial greenhouse gases, such as CO2, that contribute to anthropogenic global warming. A promising MOF that has gained the attention of the research community in recent years is the CO2 adsorbent MIL-100 (Cr). This compound consists of Cr3-μ3-oxo clusters referred to as secondary building units (SBU) and organic linkers derived from trimesic acid. Thermally activated SBUs possess coordinatively unsaturated sites Cr sites – or open metal sites (OMS) – that possess oxidation states of +2 or +3. Previous experimental work indicated that CO2 molecules bind more strongly to +2 OMS than to +3 OMS at low adsorptive pressures. In this study, two central questions were addressed. Firstly, can the experimentally observed OMS selectivity be verified through density functional theory (DFT) simulations? Secondly, what electronic processes are responsible for OMS selectivity? DFT computations of the binding energy, enthalpy, and free energy of CO2 adsorption onto +2 and +3 OMS verify that CO2 exhibits a significantly greater affinity for the +2 OMS. Furthermore, a comparison of the adsorption charge transfer and optimized binding geometries reveal that this selectivity arises from the energetically favorable chemisorption of CO2 onto +2 OMS – relative to the weaker physisorption of the greenhouse gas onto +3 OMS. The novel methodology utilized for this study can be implemented in computational investigations of other MOFs that can be used for carbon capture applications.Item Computationally modeling the effectiveness of Pd/Cu as a diesel oxidation catalyst(2023-04-13) Hammond, Nikki; Hoang, NhiDiesel engine emissions are a major cause of air pollution producing carbon monoxide (CO), hydrocarbons, nitrogen oxide molecules (NOx), and particulate matter (PM). Low temperature combustion engines offer a promising solution for reducing NOx and PM emissions, but in turn, the lower temperature interferes with the diesel oxidation catalyst (DOC) causing an increase in CO and hydrocarbon emissions. To combat this, the development of new catalysts is critical. Recent studies show that a Pd/Cu alloy could lead to inhibition-free low temperature oxidation reactions, but the mechanistic origin of the improvement over Pd/Pt alloys remains unknown. To elucidate the mechanism, we first used SurfaceEP, a machine-learning package to rapidly estimate binding energies and identified certain ensembles with promising oxygen binding properties. For isolated Pd atoms in the surface of Cu, we obtained density functional theory (DFT) data for all CO oxidation steps. We are currently incorporating this information into a kinetic Monte Carlo (kMC) model, which will allow us to study the mechanism and activity of well-defined site ensembles. This will provide the necessary fundamental insight that is required to further improve the composition and surface architecture of Pd/Cu diesel oxidation catalyst.Item Drag Coefficient for Stokes Flow(2022-04-14) Patel, AadarshiAlthough the flow around a sphere is a problem well-understood at all ranges of Reynolds number, the flow around a cylinder is an unresolved problem at creeping flow conditions. At creeping flow, Reynolds number is small, typically less than one. Because flows with such small Reynolds numbers are important academically, the focus of this research was to examine them by finding their drag coefficient. The drag coefficient is another crucial number since it relates directly to the drag force. To carry out this task successfully, designing an efficient mesh was the first step. Results for the drag coefficient for flow around a cylinder have been dependent on the domain thus far. Hence, to make the results domain-independent, a mesh with an element size ratio of 1:1 was drawn out by hand. Then, the design was programmed using MATLAB. That code was transferred to another mesh-producing software, which generated the desired mesh on the computer. The mesh code had to be flexible to ensure that the results obtained were not dependent on the domain. This flexibility allowed the addition of numerous transitions, which alter the size of the mesh. The greater the number of transitions, the larger the mesh.Item Dynamics of Viral Nanoparticals as Reporters in Lateral Flow Essays(2022-04-14) Martinez, AnastasiaItem Epoxidation and Curing of Bio-Renewable para-Coumaric Acid(2023-04-13) Sherif, NehaEpoxy resin is a thermoset polymer made from epoxy monomers combined with a curing agent. It is commonly used for products that require rigidness and durability, however, once they are no longer usable, they accumulate in landfill waste as they are not biodegradable due to their production from crude oil and thus are highly resistant to breaking down in the environment. Therefore, it is of interest to replace nonrenewable starting materials such as petroleum with a renewable feedstock. One such substance from which epoxy monomers can be derived from is lignin, a complex monomer found in the cell wall of plants that is often a waste by-product in the paper industry as it weakens the paper. Under the right conditions, lignin can be depolymerized into a mixture of small molecules that have rigid aromatic rings, making them a promising starting material for synthesizing epoxy resins. This project focused on a small molecule of the complex lignin structure called para-coumaric acid which was epoxidized and the new structure was characterized. This was done using a two-step synthesis where, first, the para-coumaric acid was allylated using allyl bromide. Once the allylated compound was verified using NMR, the double bond in the allylated coumaric acid was epoxidized with meta-chloroperoxy benzoic acid to get epoxy groups. NMR was once again used to characterize the new epoxidized para-coumaric acid. This novel monomer was then cured with an anhydride curing agent to create epoxy resin which was then tested to find its thermal properties.Item High-throughput tuning of methacrylic-acid-based hydrogels with calcium and chitosan as secondary ionic cross-linkers(2023-04-13) Allen, Natalie; Rabago, Leonardo; Valdez, Lizbet; Wallaert, SamuelCovalent hydrogel networks predominantly derived from methacrylic acid were developed as a platform for the exploration of atomic (in the form of calcium) and biopolymer polyelectrolyte (in the form of chitosan) secondary ionic cross-linkers. Well-defined chitosan was prepared from chitin and incorporated at various loadings in hydrogel precursor solutions, resulting in template polymerizations. Resultant hydrogels were soaked in various concentrations of aqueous calcium chloride and characterized by compression testing.Item Integrated Process for Red Algae Culturing and Processing High Value Algal Products: EPS & CPS, B-PE and PUFAs(2022-04-14) Nguyen, AnhThe global demand for algae and algal products are increasing over years. However, the cost for current commercial processing and purifying of algae products for good biological activities is quite high. This project aims to develop an integrated process to increase the Exopolysaccharide (EPS) and Capsular polysaccharide (CPS) yield and produce other high value co-products (B-phycoerythrin(B-PE), and poly-unsaturated fatty acids (PUFAs)) from red algae. The two-state culture process with white and green light is promising for high yield of EPS. The EPS is successful extracted by the acid precipitate method for commercial algae water. The enzyme-based extraction with the combination of alpha- and gluco-amylase enzyme yield much more B-PE compared to other reported methods. PUFA extraction by low-cost solvent helps reduce the production cost and promises for recycle of the water. This integrated process is not only promising to produce algal products at low cost but also recycle processing water for subsequent algae cultivation benefiting environment.Item Long COVID: Elucidating the Impact of COVID-19 on Black Male Engineering Students - Highlighting their Resilient Assets(2023-04-13) Elmouden, Fatima; Davis, Jared L.In 2020, the COVID-19 pandemic had a widespread effect on university students. From the shutdown of university campuses nationwide to the switch from in-person to online teaching, this sudden change's negative and positive impacts have been studied on a general and university-to-university basis. However, there remains a dearth of published research that describes the lived experiences of Black male engineering students during this time. Therefore, through secondary data analysis of our original study around the career aspirations of Black male engineering students, this study aimed to investigate how Black male engineering students were affected by the COVID-19 pandemic. We conducted semi-structured interviews with 20 Black male engineering students. Using reflexive thematic analysis, we inductively developed four themes: peer interaction and engagement, professor-student interaction, course modality experiences and accommodations, and academic adjustment and discipline. The findings illuminate the resilience of Black male engineering students. Though the participants reported setbacks due to the effect of the pandemic on their academic pursuits, they also reported an unwavering ability to adapt and reframe those setbacks in positive ways that allowed them to push forward. ***This project was completed with contributions from Erik M. Hines and Tyron Slack from Florida State University.Item Potential of Enhanced Geothermal System: A simulation study(2023-04-13) Dang, JustinEGS systems extract heat by circulating a fluid (such as water) through hot rock deep in the ground and can use that heat to produce electrical power. Here we investigate a system where one injection well and two production wells have horizontal sections connected by several transverse hydraulic fractures, thus providing large heat transfer are for the working fluid to pick up heat from the hot rock and transfer it to the surface. The aim of the study is to provide a tool for rapid order-of-magnitude assessment of the effects of essential design variables on the circulating water temperature at the production well outlet as well as on power generation. Our analytical model is based on a simplified version of a model that appeared in literature (Gringarten et al., 1975). Modeling simplifications respect mass and energy conservation laws, but allow for an analytical solution of the simplified partial differential equations, thus enabling rapid parametric investigations. Based on the simplified model, we built an interactive simulation in Mathematica, which produces the rate of heat extraction as well as the water temperature at the outlet as a function of fracture dimensions, fracture spacing, and water flow rate. Simulations indicated that the outlet temperature will drop for an increase in well spacing or water flow rate per well, and a decrease in fracture radius. Similarly, an increase in fracture are enables heat transfer increase towards the thermodynamic upper bound.Item Shape-Selective Filtration Using Block Copolymer Membranes(2022-04-14) Armijo, EdwardThere's a critical need for reliable and equitable access to safe drinking water, and it is a major and growing challenge worldwide. Safe and readily available water is important for public health, whether it is used for drinking, domestic use, food production, or recreational purposes. One method that has been of particular interest to purify water is using Ultra Filtration (UF) membranes with a pore size range of 1-100 nm. UF commercial membranes have found utility in the decontamination of drinking water, wastewater treatment, and membrane bioreactors. Unfortunately, UF membranes are limited by the stochastic pore sizes and undesirable surface chemistry which results in inadequate separations and prone to fouling. Alternatively, recent research shows that a more successful method to purify water is to utilize Block Copolymer (BCP) membranes. BCPs membranes have the capability to self-assemble into well-defined domains of uniform size thus improving size selectivity and fouling resistance. BCPs are casted as thin films where the self-assembled nanostructure serves as a template for pore generation. Pores are generated by selectively moving (etching) one of the domains and the pore size depends on the molar mass of the etchable domain. The most common morphology studied are cylindrical nanopores. As part of my SURF research program, we have developed slit based membrane using block copolymer lamellar structures and have demonstrated the shape selective filtration of Dextran using these membranes. Such membranes posses the potential for size selective filtration of proteins, viruses and pharmaceutical drugs.Item Using predictive modeling to improve catalyst performance in low temperature diesel combustion(2022-04-14) Hammond, NikkiDiesel engine emissions are a major cause of air pollution producing carbon monoxide (CO), hydrocarbons, nitrogen oxide molecules (NOx), and particulate matter (PM). Low temperature combustion engines offer a promising solution for reducing NOx and PM emissions, but in turn, the lower temperature interferes with the diesel oxidation catalyst (DOC) causing an increase in CO and hydrocarbon emissions. To combat this, the development of new catalysts is critical. Recent studies by Song et. all show that a Pd/Cu alloy could lead to inhibition-free low temperature oxidation reactions. By modifying a python modeling package, Surface EP, a number of variations of Pd/Cu surfaces can be predicted quickly and with relative accuracy. The program develops a three by three surface cell and can test for binding energies with Oxygen at the three possible site locations (Top, Bridge, and Hollow). These variations are then screened for the best possible matches. Further testing can then be conducted for additional binding energies in the oxidation reaction using Density Functional Theory (DFT) calculations.Item Z-Rings as a Biomarker in Persister Resuscitation(2023-04-13) Wagner, IvaBacterial infections that survive anti-microbial treatments are a growing concern in the medical field. Much of this research is focused on antibiotic resistance, but bacterial persistence is an equal contributor to the problem. Persister cells are a subpopulation of bacteria that are transiently capable of surviving antibiotics. The surviving bacteria remain after treatment and can resuscitate causing chronic infections. To research resuscitation in these persistent cells properly, we first need to be able to identify which cells to study; using biomarkers is one way to determine which persister cells are capable of resuscitation. One possible biomarker is the formation of z-rings during the growth-inhibited state. Using both Gentamicin and Streptomycin antibiotics, the length of time needed to kill off all but persistent cells is determined using a biphasic kill curve generated using survival assays. The length of treatment is used to treat a culture until only persisters remain. The persisters are then starved in PBS for two days to allow time for the formation Z-rings. The bacteria are then moved onto a microscope slide lined with LB agar which provides nutrients to facilitate resuscitation. Pictures in both phase contrast and gfp fluorescence are taken every hour after plating to monitor the growth and Z-rings. If the formation of Z-rings in the growth-inhibited state holds true as a biomarker, then we can use them to determine which cells are viable for resuscitation study; these cells can then be used to advance the field of persistence research further.