Concepts from electrical engineering can be introduced to nonmajor engineering students through lectures, laboratories, or even research experiences. Often the purpose of introducing nonmajors to these concepts is to highlight that engineering problems are not limited to skills from only a single discipline as well as improve their ability to communicate and collaborate with other disciplines. This case study discusses the experience of introducing a nonmajor undergraduate student to electrical engineering through an undergraduate research project at The University of Alabama investigating the electrical properties of bamboo, which required the characterization of a portable moisture meter. These exercises were successful at improving the student's confidence and proficiency with electrical test equipment, highlighting the limitations of test equipment, and applying concepts of resistance to a real-world application that overlaps electrical, chemical, and biological disciplines. While this exercise was a component of an undergraduate research experience, similar exercises could be easily integrated into electrical engineering laboratories for nonelectrical engineering majors to introduce and reinforce concepts from electrical engineering using a multidisciplinary application.
We describe the validation of a novel polymeric equilibrium passive sampler comprised of agarose gel with embedded activated carbon particles (ag+AC), to estimate aqueous monomethylmercury (MeHg) concentrations. Sampler behavior was tested using a combination of idealized media and realistic sediment microcosms. Isotherm bottle experiments with ag+AC polymers were conducted to constrain partitioning to these materials by various environmentally relevant species of MeHg bound to dissolved organic matter (MeHgDOM) across a range of sizes and character. Log of partitioning coefficients for passive samplers (K ps ) ranged from 1.98 ± 0.09 for MeHg bound to Suwannee River humic acid to 3.15 ± 0.05 for MeHg complexed with Upper Mississippi River natural organic matter. Reversible equilibrium exchange of environmentally relevant MeHg species was demonstrated through a series of dual isotope-labeled exchange experiments. Isotopically labeled MeHgDOM species approached equilibrium in the samplers over 14 days, while mass balance was maintained, providing strong evidence that the ag+AC polymer material is capable of equilibrium measurements of environmentally relevant MeHg species within a reasonable deployment time frame. Samplers deployed across the sediment-water interface of sediment microcosms estimated both overlying water and porewater MeHg concentrations within a factor of 2 to 4 of measured values, based on the average measured K ps values for species of MeHg bound to natural organic matter in the isotherm experiments. Taken together, our results indicate that ag+AC polymers, used as equilibrium samplers, can provide accurate MeHg estimations across many site chemistries, with a simple back-calculation based on a standardized K ps.
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