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Practicality of 3D-Printing for Robotics Applications in Abrasive Environments
Manufacturing processes performed within an abrasive environment or including abrasive materials may be subject to damage of the tooling involved, shortening the effective life cycle of said tooling. In these cases, the cost-effectiveness of these processes may be increased by replacing the material used for tooling with a 3D-printed polymer. A common type of tooling known as robotic grippers have a variety of applications including product assembly, lab automation, and machine tending, among others. The most common type of material used for robotic grippers is aluminum, and while aluminum possesses significantly greater strength than most polymers, the cost of an aluminum pair of robotic grippers would be substantially more than an identical 3D-printed polymer pair, especially if the grippers are of a complex or otherwise non-standard design. To evaluate the durability of 3D-printed polymer grippers we chose to focus on the process of machine tending, in which the robotic grippers must often handle a raw material. Raw materials are known to possess some degree of surface roughness, which over time may degrade the grippers to the point of non-functionality. 3D-printed polymer grippers were modeled after the standard grippers of a FANUC LR Mate 200iD robotic arm and attached to said robotic arm, then cycled through the process of repeatedly manipulating an abrasive material until failure. By comparing the life cycle of the polymer grippers (in cycles until failure) to that of the aluminum grippers, weighted by the production cost of each, the ratio of cost-effectiveness was able to be determined.Development of FRET-based Assay to Pbserve Binding of RNA Modification Enzyme RsuA-127 to 5' Domain of 16S Ribosomal RNA
Ribosomes are the molecular machines that carry out protein biosynthesis in all living organisms. Bacterial ribosomes are composed of three different ribosomal RNAs (16S, 23S and 5S)and more than 50 different ribosomal proteins. The thermodynamics and kinetics of in vitro ribosomal assembly have been studied extensively. However, during ribosome biogenesis in vivo, ribosome assembly occurs concurrently with transcription, folding, post-transcriptional modifications and processing of rRNA. Unfortunately, the effects of nucleotide modifications and their respective modification enzymes on ribosomal assembly are understudied. My project in Abey lab is to investigate how RNA modification enzyme RsuA interacts with 16S rRNA and other primary assembly proteins such as S4, S17, and S20 during bacterial ribosome assembly. A fluorescence based assay was used to monitor the RsuA binding to the 16S rRNA in the presence of other ribosomal proteins that are binding near the RsuA binding site. We observed that protein RsuA is cooperative with protein S17 for its binding but anti-cooperative with protein S4. Furthermore, our results suggested that protein RsuA prefers extended h18 structure for its binding.- Image
Evaluation of the Impact of a Multistep Synthesis Project
A multistep synthesis project was implemented in an Organic Chemistry II laboratory course for two years. Multistep synthesis is an alternative to traditional cookbook labs that has a greater resemblance to real-world synthesis. In this project, students worked in groups to perform a series of six reactions that led to the production of hexaphenylbenzene, and they then conveyed their results in a Journal of Organic Chemistry formatted paper. Goals for the course included for students to perform synthesis of organic molecules, to communicate their results in a written report, to have lecture material reinforced, and to be introduced to green chemistry concepts. At the end of the course, students completed a survey with 16 open-ended questions probing their ideas about the lab, such as what they believed the purpose and value of it was. Open coding and analysis of the 113 student responses suggested course goals were met and revealed an alignment between the instructor intended purpose, student perceived purpose, and student perceived value. Several students noted how the multistep aspect of the project made their work feel more important because each week’s product was used the following week as opposed to being discarded as waste. Additionally, almost all students (94%) reported reactions performed in lab were taught in lecture, evidence that students made the connection between lab and lecture. These results indicate the effective implementation of a multistep synthesis project and raise further questions about its potential to provoke changes in students’ ideas about science and their process skills. A Versatile Synthesis Route for Atomically Dispersed Metal Nanoparticles on Nitrogen-doped Porous Carbon Supports
Metal nanoparticles (MNPs) have a wide range of applications in heterogeneous catalysis, electronics, sensors, and optics. However, MNPs are unstable due to the high surface energy, so aggregation occurs, which nullifies any benefits associated with the reduced particle size. To overcome this propensity, MNPs are often loaded onto porous supports, which offer many advantages including a significant boost in particle dispersion and reactive surface area, thereby improving the efficiency of MNPs. The activity of MNPs is largely attributed to the reduced particle size because the amount of reactive sites increases with decreasing particle size. For this reason, an enormous attention has been devoted to decreasing the particle size of MNPs. Although metal nanoparticles exist in small aggregates ranging in size from 10 to 50 nm, the achievement of atomic metal dispersion is a big challenge. Herein, we report a novel single-step synthesis of atomically dispersed transition metals on carbon spheres. The in-situ approach utilizes the chelating ability of polydentate ligands to form cage-like complexes around metal centers. The chelated complex confines the metal atom, which effectively prevents aggregation even at high metal concentrations. Since chelating agents have unusually large formation constants with most transition metals; the atomically dispersed metal nanoparticles can be synthesized for a wide range of metals.