Scholarly Work - Chemical & Biological Engineering
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Item A Case Study Comparison of Undergraduate Education and Engineering Majors’ Understanding of Community Engineering(Informa UK Limited, 2024-06) Vo, Tina; Hammack, Rebekah; Gannon, Paul; Lux, Nicholas; Wiehe, Blake; Moonga, Miracle; LaMeres, BrockAs we prepare teachers to provide students with opportunities within STEM education, authentic experiences should guide the instruction. Unfortunately, due to the novel integration of engineering into national reform documents, there is a dearth of documentation on elementary preservice teachers’ engineering ideas as they align with student goals (e.g. enrolling in an engineering program). As teachers must provide authentic science experiences to help frame the work of scientists for students, creating authentic engineering experiences should frame the work of engineers. Thus, it is important to foundationally investigate how elementary preservice teachers’ ideas about engineering reflect those of novice engineers. This research uses multiple case study to investigate and compare teaching and engineering majors’ understanding of engineering within their communities. Additionally, while there were some similarities across groups, engineering majors were more likely to speak to the science behind the artifacts represented in the photo novellas they authored, and the preservice teachers found a larger variety and diversity of engineering elements. Findings indicate that these groups have fundamentally different perspectives on engineering and how it is manifested within the communities. This has implications for upper tiers of education as elementary teachers lay broad engineering foundations, while middle, high school, and community colleges must methodically highlight engineering disciplines to provide more authentic experiences, highlighting the connections between engineering, science, and math.Item Hybrid Radial-Axial Flow for Enhanced Thermal Performance in Packed Bed Energy Storage(Wiley, 2024-10) Al-Azawii, Mohammad M. S.; Anderson, RyanIn this work, a hybrid radial-axial (HRA) system is used to store thermal energy in a packed bed. The heat transfer fluid (HTF) is delivered via a perforated radial pipe placed at the center of the packed bed along the axial length. Hot fluid flows from the center toward the wall through the holes (like other radial systems), but then leaves via the traditional axial flow exit, creating the HRA flow configuration. A computational fluid dynamics (CFD) model is used to analyze the thermal performance of the packed bed during the charging process utilizing the new HRA system. Alumina beads of 6 mm were filler materials and air was HTF with inlet temperature of 75°C for proof of concept. The present paper focuses on two aims: (1) utilizing CFD models to analyze flow and temperature profiles in the packed bed; (2) comparing the model results to experimental results published in a previous HRA flow study and to traditional axial flow. Two HRA configurations were considered based on previous experimental designs, one with uniform holes in the central pipe (R1) and one with gradients in the hole sizes to promote even flow from the central pipe into the bed (R2). The numerical results agree with the experimental results in both cases. The HRA system performance depends on the flow profile created by the hole designs, and it can perform better than the axial flow depending on the design of the radial pipe. Design R2, which promotes even flow from the central pipe into the bed, has higher charging efficiency than standard axial flow methods. For HRA design R2 at 0.0048 m3/s (7 SCFM, standard cubic feet per minute), numerical results for charging efficiency were 75.5% versus 73.8% for traditional axial flow. For HRA design R2 at 0.0061 m3/s (9 SCFM), numerical charging efficiency was 80.5% versus 78.1% for traditional axial flow. These results are consistent with experimental data.Item Selenate bioreduction in a large in situ field trial(Elsevier BV, 2024-04) Hendry, M. Jim; Kirk, Lisa; Warner, Jeff; Shaw, Shannon; Peyton, Brent M.; Schmeling, Erin; Barbour, S. LeeRemoving selenium (Se) from mine effluent is a common challenge. A long-term, in situ experiment was conducted to bioremediate large volumes (up to 7500 mc d−1) of Se(VI)-contaminated water (mean 87 μg L−1) by injecting the water into a saturated waste rock fill (SRF) at a coal mining operation in Elk Valley, British Columbia, Canada. To stimulate/maintain biofilm growth in the SRF, labile organic carbon (methanol) and nutrients were added to the water prior to its injection. A conservative tracer (Br−) was also added to track the migration of injected water across the SRF, identify wells with minimal dilution and used to quantify the extent of bioreduction. The evolution of the Se species through the SRF was monitored in time and space for 201 d. Selenium concentrations of <3.8 μg L−1 were attained in monitoring wells located 38 m from the injection wells after 114 to 141 d of operation. Concentrations of Se species in water samples from complementary long-term (351–498 d) column experiments using influent Se(VI) concentrations of 1.0 mg L−1 were consistent with the results of the in situ experiment. Solid samples collected at the completion of the column experiments confirmed the presence of indigenous Se-reducing bacteria and that the sequestered Se was present as insoluble Se(0), likely in Se-S ring compounds. Based on the success of this ongoing bioremediation experiment, this technology is being applied at other mine sites.Item Influence of Copper on Oleidesulfovibrio alaskensis G20 Biofilm Formation(MDPI AG, 2024-08) Thankur, Payal; Gopalakrishnan, Vinoj; Saxena, Priya; Subramaniam, Mahadevan; Mau Goh, Kian; Peyton, Brent; Fields, Matthew; Kumar Sani, RajeshCopper is known to have toxic effects on bacterial growth. This study aimed to determine the influence of copper ions on Oleidesulfovibrio alaskensis G20 biofilm formation in a lactate-C medium supplemented with variable copper ion concentrations. OA G20, when grown in media supplemented with high copper ion concentrations of 5, 15, and 30 µM, exhibited inhibited growth in its planktonic state. Conversely, under similar copper concentrations, OA G20 demonstrated enhanced biofilm formation on glass coupons. Microscopic studies revealed that biofilms exposed to copper stress demonstrated a change in cellular morphology and more accumulation of carbohydrates and proteins than controls. Consistent with these findings, sulfur (dsrA, dsrB, sat, aprA) and electron transport (NiFeSe, NiFe, ldh, cyt3) genes, polysaccharide synthesis (poI), and genes involved in stress response (sodB) were significantly upregulated in copper-induced biofilms, while genes (ftsZ, ftsA, ftsQ) related to cellular division were negatively regulated compared to controls. These results indicate that the presence of copper ions triggers alterations in cellular morphology and gene expression levels in OA G20, impacting cell attachment and EPS production. This adaptation, characterized by increased biofilm formation, represents a crucial strategy employed by OA G20 to resist metal ion stress.Item Reactive Condensation of Cr Vapor on Aluminosilicates Containing Alkaline Oxides(The Electrochemical Society, 2024-08) Van Leeuwen, Travis; Guerrero, Amberly; Dowdy, Ryan; Satritama, Bima; Rhamdhani, Akbar; Will, Geoffrey; Gannon, PaulThis study is part of a series with the objective of improving fundamental understanding of reactive condensation of Chromium (Cr) vapors, which are generated from Cr containing alloys used in many high-temperature (>500 °C) process environments and can form potentially problematic condensed hexavalent (Cr(VI)) species downstream. This study specifically focuses on the effects of alkaline oxide additives in aluminosilicate fibers on Cr condensation and speciation. Cr vapors were generated by flowing high-temperature (800 °C) air containing 3% water vapor over chromia (Cr2O3) powder, with aluminosilicate fiber samples positioned downstream where the temperature decreases (<500 °C). Total condensed Cr and ratios of oxidation states were measured using inductively coupled plasma optical emission spectroscopy (ICP-OES) and diphenyl carbazide (DPC) colorimetric/direct UV–vis spectrophotometric analyses. Results indicate presence of hexavalent Cr (Cr(VI)) species condensed on all samples investigated. The ratio of Cr(VI) to total Cr detected was consistently higher on aluminosilicate fiber samples containing alkaline oxide (CaO and MgO) additions. Computational thermodynamic equilibrium modelling corroborated experimental results showing stabilities of Ca and Mg chromate (Cr(VI)) compounds. Comparative results and analyses are presented and discussed to help inform mechanistic understanding and future related research and engineering efforts.Item Solubility of 2,5-Furandicarboxylic Acid in Pure and Mixed Organic Solvent Systems at 293 K Predicted Using Hansen Solubility Parameters(American Chemical Society, 2024-07) Molinaro, Jacob M.; Carroll, M.; Marchan, Gabriela T.; Wettstein, Stephanie G.Central to the production of polyethylene furanoate (PEF), a bioplastic that could potentially replace petroleum-derived plastics, is 2,5-furandicarboxylic acid (FDCA). FDCA is a chemical derived from biomass that has low solubility in traditionally used solvents such as water. Thus, identifying solvents that can solubilize significant amounts of FDCA could allow for lower PEF production costs. In this study, FDCA solubility was investigated in nine pure solvents including H2O, acetonitrile (ACN), γ-valerolactone (GVL), γ-butyrolactone (GBL), ethanol (EtOH), methanol (MeOH), dimethyl sulfoxide (DMSO), sulfolane (SULF), and tetrahydrofuran (THF), eight binary, and three ternary solvent blends at 293 K. For all binary systems excluding DMSO and MeOH, the solubility of FDCA increased 1.5–65 times compared to the pure organic solvent, and the FDCA solubility was at least 10 times higher when compared to pure water. Specifically, the 20/80 w/w H2O/DMSO system solubilized 23.1 wt % FDCA, the highest of any binary blend studied, and 190 times more solubility than in pure water. In 20/80 w/w H2O/THF, the FDCA solubility was 60 times higher than pure water. In ternary blends that included DMSO, H2O, and either GVL, THF, or SULF, solubility increased by at least 6.6 times relative to the pure secondary organic component and 54 times relative to pure water. Using Hansen solubility parameters (HSPs), the radius of interaction (Ri, j) was found to be more strongly correlated to FDCA solubility than individual HSPs or the total solubility parameter. A MATLAB-based optimization code was developed and successful in minimizing the Ri, j of a solvent blend to maximize FDCA solubility in binary and ternary aqueous solvents.Item Beyond the Surface: Non-Invasive Low-Field NMR Analysis of Microbially-Induced Calcium Carbonate Precipitation in Shale Fractures(Springer Science and Business Media LLC, 2024-07) Willett, Matthew R.; Bedey, Kayla; Crandall, Dustin; Seymour, Joseph D.; Rutqvist, Jonny; Cunningham, Alfred B.; Phillips, Adrienne J.; Kirkland, Catherine M.Microbially-induced calcium carbonate precipitation (MICP) is a biological process in which microbially-produced urease enzymes convert urea and calcium into solid calcium carbonate (CaCO3) deposits. MICP has been demonstrated to reduce permeability in shale fractures under elevated pressures, raising the possibility of applying this technology to enhance shale reservoir storage safety. For this and other applications to become a reality, non-invasive tools are needed to determine how effectively MICP seals shale fractures at subsurface temperatures. In this study, two different MICP strategies were tested on 2.54 cm diameter and 5.08 cm long shale cores with a single fracture at 60 ℃. Flow-through, pulsed-flow MICP-treatment was repeatedly applied to Marcellus shale fractures with and without sand (“proppant”) until reaching approximately four orders of magnitude reduction in apparent permeability, while a single application of polymer-based “immersion” MICP-treatment was applied to an Eagle Ford shale fracture with proppant. Low-field nuclear magnetic resonance (LF-NMR) and X-Ray computed microtomography (micro-CT) techniques were used to assess the degree of biomineralization. With the flow-through approach, these tools revealed that while CaCO3 precipitation occurred throughout the fracture, there was preferential precipitation around proppant. Without proppant, the same approach led to premature sealing at the inlet side of the core. In contrast, immersion MICP-treatment sealed off the fracture edges and showed less mineral precipitation overall. This study highlights the use of LF-NMR relaxometry in characterizing fracture sealing and can help guide NMR logging tools in subsurface remediation efforts.Item Digital droplet RT-LAMP increases speed of SARS-CoV-2 viral RNA detection(Wiley, 2024-06) Yuan, Yuan; Ellis, Perry; Tao, Ye; Bikos, Dimitri A.; Loveday, Emma K.; Thomas, Mallory M.; Wilking, James N.; Chang, Connie B.; Ye, Fangfu; Weitz, David A.Nucleic acid amplification testing (NAAT) remains one of the most reliable methods for pathogen identification. However, conventional bulk NAATs may not be sufficiently fast or sensitive enough for the detection of clinically-relevant pathogens in point-of-care testing. Here, we have developed a digital droplet RT-LAMP (ddRT-LAMP) assay that rapidly and quantitatively detects the SARS-CoV-2 viral E gene in microfluidic drops. Droplet partitioning using ddRT-LAMP significantly accelerates detection times across a wide range of template concentrations compared to bulk RT-LAMP assays. We discover that a reduction in droplet diameter decreases assay times up to a certain size, upon which surface adsorption of the RT-LAMP polymerase reduces reaction efficiency. Optimization of drop size and polymerase concentration enables rapid, sensitive, and quantitative detection of the SARS-CoV-2 E gene in only 8 min. These results highlight the potential of ddRT-LAMP assays as an excellent platform for quantitative point-of-care testing.Item High Selectivity Reactive Carbon Dioxide Capture over Zeolite Dual-Functional Materials(American Chemical Society, 2024-05) Crawford, James M.; Rasmussen, Matthew J.; McNeary, W. Wilson; Halingstad, Sawyer; Hayden, Steven C.; Dutta, Nikita S.; Pang, Simon H.; Yung, Matthew M.Reactive carbon dioxide capture (RCC) is a process where carbon dioxide (CO2) is captured from a mixed gas stream (such as air) and converted to products without first performing a separation step to concentrate the CO2. In this work, zeolite dual-functional materials (ZFMs) are introduced and evaluated for simulated RCC. The studied ZFMs feature high surface area, crystalline, microporous zeolite faujasite (FAU) as the support. Sodium oxide (“Na2O”) is impregnated as an effective capture agent capable of scavenging low concentration CO2 (1,000 ppm). Exchanged and impregnated sodium on FAU chemisorbs CO2 as carbonates and bicarbonates but does not promote the conversion of sorbed CO2 to products when heated in hydrogen. The addition of Ru promotes the formation of formates, while the addition of Pt generates carbonyl surface species when heated in hydrogen. The active metal then promotes extremely high selectivity for CO2 hydrogenation to either methane on Ru catalyst (∼150 °C) or carbon monoxide on Pt catalyst (∼200 °C) when heated in reducing atmospheres.Item Rapamycin does not alter bone microarchitecture or material properties quality in young-adult and aged female C57BL/6 mice(Oxford University Press, 2024-01) Devine, Connor C.; Brown, Kenna C.; Paton, Kat O.; Heveran, Chelsea M.; Martin, Stephen A.Advancing age is the strongest risk factor for osteoporosis and skeletal fragility. Rapamycin is an FDA-approved immunosuppressant that inhibits the mechanistic target of rapamycin (mTOR) complex, extends lifespan, and protects against aging-related diseases in multiple species; however, the impact of rapamycin on skeletal tissue is incompletely understood. We evaluated the effects of a short-term, low-dosage, interval rapamycin treatment on bone microarchitecture and strength in young-adult (3 mo old) and aged female (20 mo old) C57BL/6 mice. Rapamycin (2 mg/kg body mass) was administered via intraperitoneal injection 1×/5 d for a duration of 8 wk; this treatment regimen has been shown to induce geroprotective effects while minimizing the side effects associated with higher rapamycin dosages and/or more frequent or prolonged delivery schedules. Aged femurs exhibited lower cancellous bone mineral density, volume, trabecular connectivity density and number, higher trabecular thickness and spacing, and lower cortical thickness compared to young-adult mice. Rapamycin had no impact on assessed microCT parameters. Flexural testing of the femur revealed that both yield strength and ultimate strength were lower in aged mice compared to young-adult mice. There were no effects of rapamycin on these or other measures of bone biomechanics. Age, but not rapamycin, altered local and global measures of bone turnover. These data demonstrate that short-term, low-dosage interval rapamycin treatment does not negatively or positively impact the skeleton of young-adult and aged mice.