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1. Integrating Professional Mentorship with a 3D-Printing Curriculum to Help Rural Youth Forge STEM Career Connections.

   Bhaduri, S. ( July 2021 , 2021 ASEE Virtual Annual Conference.)

   Economically disadvantaged youth residing in mountain tourist communities represent an important and understudied rural population. These communities typically include a large percentage of children that are English language learners. Our NSF STEM Career Connections project, A Model for Preparing Economically-Disadvantaged Rural Youth for the Future STEM Workplace, investigates strategies that help middle school youth in these communities to envision a broader range of workforce opportunities, especially in STEM and computing careers. This poster highlights the initial findings of an innovative model that involves working with local schools and community partners to support the integration of local career contexts, engineering phenomena, 3D printing technologies, career connections, and mentorship into formal educational experiences to motivate and prepare rural youth for future STEM careers. We focus on select classrooms at two middle schools and describe the implementation of a novel 3D printing curriculum during the 2020-2021 school-year. Two STEM teachers implemented the five-week curriculum with approximately 300 students per quarter. To create a rich inquiry-driven learning environment, the curriculum uses an instructional design approach called storylining. This approach is intended to promote coherence, relevance, and meaning from the students’ perspectives by using students’ questions to drive investigations and lessons. Students worked towards answering the question: “How can we support animals with physical disabilities so they can perform daily activities independently?” Students engaged in the engineering design process by defining, developing, and optimizing solutions to develop and print prosthetic limbs for animals with disabilities using 3D modeling, a unique augmented reality application, and 3D printing. In order to embed connections to STEM careers and career pathways, some students received mentorship and guidance from local STEM professionals who work in related fields. This poster will describe the curriculum and its implementation across two quarters at two middle schools in the US rural mountain west, as well as the impact on students’ interest in STEM and computing careers. During the first quarter students engaged in the 3D printing curriculum, but did not have access to the STEM career and career pathway connections mentorship piece. During the second quarter, the project established a partnership with a local STEM business -- a medical research institute that utilizes 3D printing and scanning for creating human surgical devices and procedures -- to provide mentorship to the students. Volunteers from this institute served as ongoing mentors for the students in each classroom during the second quarter. The STEM mentors guided students through the process of designing, testing, and optimizing their 3D models and 3D printed prosthetics, providing insights into how students’ learning directly applies to the medical industry. Different forms of student data such as cognitive interviews and pre/post STEM interest and spatial thinking surveys were collected and analyzed to understand the benefits of the career connections mentorship component. Preliminary findings suggest the relationship between local STEM businesses and students is important to motivate youth from rural areas to see themselves being successful in STEM careers and helping them to realize the benefits of engaging with emerging engineering technologies. 

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2. Modular, Articulated Models of DNA and Peptide Nucleic Acids for Nanotechnology Education

   https://doi.org/10.35459/tbp.2022.000225  

   Goodwin-Schoen, Caleigh M. ; Taylor, Rebecca E. ( April 2023 , The Biophysicist)

   Dynamic and flexible nucleic acid models can provide current and future scientists with physical intuition for the structure of DNA and the ways that DNA and its synthetic mimics can be used to build self-assembling structures and advanced nanomachines. As more research labs and classrooms dive into the field of structural nucleic acid nanotechnology, students and researchers need access to interactive, dynamic, handheld models. Here, we present a 3D-printable kit for the construction of DNA and peptide nucleic acid (PNA). We have engineered a previous modular DNA kit to reduce costs while improving ease of assembly, flexibility, and robustness. We have also expanded the scope of available snap-together models by creating the first 3D-printable models of γPNA, an emerging material for nuclease- and protease-resistance nanotechnology. Building on previous research, representative nucleic acid duplexes were split into logical monomer segments, and atomic coordinates were used to create solid models for 3D printing. We used a human factors approach to customize 3 types of articulated snap-together connectors that allow for physically relevant motion characteristic of each interface in the model. Modules are easy to connect and separate manually but stay together when the model is manipulated. To greatly reduce cost, we bundled these segments for printing, and we created a miniaturized version that uses less than half the printing material to build. Our novel 3D-printed articulated snap-together models capture the flexibility and robustness of DNA and γPNA nanostructures. Resulting handheld helical models replicate the geometries in published structures and can now flex to form crossovers and allow biologically relevant zipping and unzipping to allow complex demonstrations of nanomachines undergoing strand displacement reactions. Finally, the same tools used to create these models can be readily applied to other types of backbones and nucleobases for endless research and education possibilities.

    

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3. The Global Care Ecosystems of 3D Printed Assistive Devices

   https://doi.org/10.1145/3537676  

   Savage, Saiph ; Flores-Saviaga, Claudia ; Rodney, Rachel ; Savage, Liliana ; Schull, Jon ; Mankoff, Jennifer ( January 2022 , ACM Transactions on Accessible Computing)

   The popularity of 3D printed assistive technology has led to the emergence of new ecosystems of care, where multiple stakeholders (makers, clinicians, and recipients with disabilities) work toward creating new upper limb prosthetic devices. However, despite the increasing growth, we currently know little about the differences between these care ecosystems. Medical regulations and the prevailing culture have greatly impacted how ecosystems are structured and stakeholders work together, including whether clinicians and makers collaborate. To better understand these care ecosystems, we interviewed a range of stakeholders from multiple countries, including Brazil, Chile, Costa Rica, France, India, Mexico, and the U.S. Our broad analysis allowed us to uncover different working examples of how multiple stakeholders collaborate within these care ecosystems and the main challenges they face. Through our study, we were able to uncover that the ecosystems with multi-stakeholder collaborations exist (something prior work had not seen), and these ecosystems showed increased success and impact. We also identified some of the key follow-up practices to reduce device abandonment. Of particular importance are to have ecosystems put in place follow up practices that integrate formal agreements and compensations for participation (which do not need to be just monetary). We identified that these features helped to ensure multi-stakeholder involvement and ecosystem sustainability. We finished the paper with socio-technical recommendations to create vibrant care ecosystems that include multiple stakeholders in the production of 3D printed assistive devices. 

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4. (Digital Presentation) Accelerating the Conversion Process of Polysulfides in High Mass Loading Sulfur Cathode for the Longevity Li-S Battery

   https://doi.org/10.1149/MA2022-012383mtgabs  

   Zhang, Yuxuan ; Kivevele, Thomas ; Song, Han Wook ; Lee, Sunghwan ( July 2022 , ECS Meeting Abstracts)

   Conventional lithium-ion batteries are unable to meet the increasing demands for high-energy storage systems, because of their limited theoretical capacity. 1 In recent years, intensive attention has been paid to enhancing battery energy storage capability to satisfy the increasing energy demand in modern society and reduce the average energy capacity cost. Among the candidates for next generation high energy storage systems, the lithium sulfur battery is especially attractive because of its high theoretical specific energy (around 2600 W h kg-1) and potential cost reduction. In addition, sulfur is a cost effective and environmentally friendly material due to its abundance and low-toxicity. 2 Despite all of these advantages, the practical application of lithium sulfur batteries to date has been hindered by a series of obstacles, including low active material loading, poor cycle life, and sluggish sulfur conversion kinetics. 3 Achieving high mass loading cathode in the traditional 2D planar thick electrode has been challenged. The high distorsion of the traditional planar thick electrodes for ion/electron transfer leads to the limited utilization of active materials and high resistance, which eventually results in restricted energy density and accelerated electrode failure. 4 Furthermore, of the electrolyte to pores in the cathode and utilization ratio of active materials. Catalysts such as MnO 2 and Co dopants were employed to accelerate the sulfur conversion reaction during the charge and discharge process. 5 However, catalysts based on transition metals suffer from poor electronic conductivity. Other catalysts such as transition metal dopants are also limited due to the increased process complexities. . In addition, the severe shuttle effects in Li-S batteries may lead to fast failures of the battery. Constructing a protection layer on the separator for limiting the transmission of soluble polysulfides is considered an effective way to eliminate the shuttle phenomenon. However, the soluble sulfides still can largely dissolve around the cathode side causing the sluggish reaction condition for sulfur conversion. 5 To mitigate the issues above, herein we demonstrate a novel sulfur electrode design strategy enabled by additive manufacturing and oxidative vapor deposition (oCVD). Specifically, the electrode is strategically designed into a hierarchal hollow structure via stereolithography technique to increase sulfur usage. The active material concentration loaded to the battery cathode is controlled precisely during 3D printing by adjusting the number of printed layers. Owing to its freedom in geometry and structure, the suggested design is expected to improve the Li ions and electron transport rate considerably, and hence, the battery power density. The printed cathode is sintered at 700 °C at N 2 atmosphere to achieve carbonization of the cathode during which intrinsic carbon defects (e.g., pentagon carbon) as catalytic defect sites are in-situ generated on the cathode. The intrinsic carbon defects equipped with adequate electronic conductivity. The sintered 3D cathode is then transferred to the oCVD chamber for depositing a thin PEDOT layer as a protection layer to restrict dissolutions of sulfur compounds in the cathode. Density functional theory calculation reveals the electronic state variance between the structures with and without defects, the structure with defects demonstrates the higher kinetic condition for sulfur conversion. To further identify the favorable reaction dynamic process, the in-situ XRD is used to characterize the transformation between soluble and insoluble polysulfides, which is the main barrier in the charge and discharge process of Li-S batteries. The results show the oCVD coated 3D printed sulfur cathode exhibits a much higher kinetic process for sulfur conversion, which benefits from the highly tailored hierarchal hollow structure and the defects engineering on the cathode. Further, the oCVD coated 3D printed sulfur cathode also demonstrates higher stability during long cycling enabled by the oCVD PEDOT protection layer, which is verified by an absorption energy calculation of polysulfides at PEDOT. Such modeling and analysis help to elucidate the fundamental mechanisms that govern cathode performance and degradation in Li-S batteries. The current study also provides design strategies for the sulfur cathode as well as selection approaches to novel battery systems. References: Bhargav, A., (2020). Lithium-Sulfur Batteries: Attaining the Critical Metrics. Joule 4 , 285-291. Chung, S.-H., (2018). Progress on the Critical Parameters for Lithium–Sulfur Batteries to be Practically Viable. Advanced Functional Materials 28 , 1801188. Peng, H.-J.,(2017). Review on High-Loading and High-Energy Lithium–Sulfur Batteries. Advanced Energy Materials 7 , 1700260. Chu, T., (2021). 3D printing‐enabled advanced electrode architecture design. Carbon Energy 3 , 424-439. Shi, Z., (2021). Defect Engineering for Expediting Li–S Chemistry: Strategies, Mechanisms, and Perspectives. Advanced Energy Materials 11 . Figure 1 

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5. Engaging STEM Learners with Hands-on Models to Build Representational Competence

   https://doi.org/10.18260/1-2--34541  

   Davishahl, Eric ; Singleton, Lee ; Haskell, Todd ( June 2020 , 2020 ASEE Virtual Annual Conference Content Access)

   Modern 3D printing technology makes it relatively easy and affordable to produce physical models that offer learners concrete representations of otherwise abstract concepts and representations. We hypothesize that integrating hands-on learning with these models into traditionally lecture-dominant courses may help learners develop representational competence, the ability to interpret, switch between, and appropriately use multiple representations of a concept as appropriate for learning, communication and analysis. This approach also offers potential to mitigate difficulties that learners with lower spatial abilities may encounter in STEM courses. Spatial thinking connects to representational competence in that internal mental representations (i.e. visualizations) facilitate work using multiple external representations. A growing body of research indicates well-developed spatial skills are important to student success in many STEM majors, and that students can improve these skills through targeted training. This NSF-IUSE exploration and design project began in fall 2018 and features cross-disciplinary collaboration between engineering, math, and psychology faculty to develop learning activities with 3D-printed models, build the theoretical basis for how they support learning, and assess their effectiveness in the classroom. We are exploring how such models can support learners’ development of conceptual understanding and representational competence in calculus and engineering statics. We are also exploring how to leverage the model-based activities to embed spatial skills training into these courses. The project is addressing these questions through parallel work piloting model-based learning activities in the classroom and by investigating specific attributes of the activities in lab studies and focus groups. To date we have developed and piloted a mature suite of activities covering a variety of topics for both calculus and statics. Class observations and complementary studies in the psychology lab are helping us develop a theoretical framework for using the models in instruction. Close observation of how students use the models to solve problems and as communication tools helps identify effective design elements. We are administering two spatial skills assessments as pre/post instruments: the Purdue Spatial Visualizations Test: Rotations (PSVT:R) in calculus; and the Mental Cutting Test (MCT) in statics. We are also developing strategies and refining approaches for assessing representational competence in both subject areas. Moving forward we will be using these assessments in intervention and control sections of both courses to assess the effectiveness of the models for all learners and subgroups of learners. 

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