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The development of the CS content standards underscores the importance of curricula aligned with the standards, ensuring equitable coverage of CS concepts for all students. Because standards are broad, we emphasize the need for CS curricula to specify not only the standards they align with but also which aspects of the standards they align with and how. We map one common middle school CS curriculum to a few standards to demonstrate this need. 

A gas metal-directed energy deposition process was used to fabricate builds using two commercial weld fillers used in power generation applications, 16-8-2 and 316H. Microstructure stability and mechanical properties were investigated through room-temperature and elevated temperature tensile testing and creep testing at 650°C, 750°C, and 825°C. 16-8-2 exhibited reduced austenite stability which resulted in athermal martensite formation after aging at 650°C for 1000 h and strain-induced martensite formation during room-temperature tensile testing. 316H exhibited relatively higher austenite stability due to increased alloying content, resulting in no athermal martensite or strain-induced martensite. Due to lower austenite stability, ferrite formed during creep at 650°C in 16-8-2, which resulted in reduced creep life and lower creep ductility compared to 316H. At 750°C and 825°C, when ferrite is no longer thermodynamically stable, 16-8-2 exhibited longer creep life and similar creep ductility as 316H. The formation of ferrite in 16-8-2 appears to have a greater impact on creep performance than the formation of embrittling topologically close-packed phases like the σ phase, as 316H exhibited superior creep performance while predicted to form 14 vol.% σ phase at 650°C.

 

To promote a justice‐oriented approach to science education, we formed a research‐practice partnership between middle school science teachers, their students, curriculum designers, learning scientists, and experts in social justice to co‐design and test an environmental justice unit for middle school instruction. We examine teacher perspectives on the challenges and possibilities of integrating social justice into their standards‐aligned science teaching as they participate in co‐design and teach the unit. The unit supports students to investigate racially disparate rates of asthma in their community by examining pollution maps and historical redlining maps. We analyze interviews and co‐design artifacts from two teachers who participated in the co‐design and taught the unit in their classrooms. Our findings point to the benefits of a shared pedagogical framework and an initial unit featuring local historical content to structure co‐design. Findings also reveal that teachers can share similar goals for empowering students to use science knowledge for civic action while framing the local socio‐political factors contributing to the injustice differently, due in part to different institutional supports and constraints. Student interviews and a pre/postassessment illustrate how the unit facilitated students' progress in connecting socio‐political and science ideas to explain the impacts of particulate matter pollution and who is impacted most. Analyses illuminate how teachers' pedagogical choices may influence whether and how students discuss the impact of systemic racism in their explanations. The findings inform refinement of the unit and suggest supports needed for co‐design partnerships focused on integrating social justice and science.

 

A community-based mathematical modeling task focuses on exploring issues of inequities and lack of access to youth sports.

 

Austenitic stainless steels are used in power generation components subjected to elevated temperatures over long service lives. Replacing these components can involve lengthy lead times and deteriorate the robustness of the energy infrastructure. Wire arc directed energy deposition (WA-DED) has the potential to enable rapid manufacturing of replacement parts, but the long-term stability of microstructures and mechanical properties produced by WA-DED is not well understood. In this work, we explore the influence of aging at 650°C for 1000 h on the formation of embrittling phases, such as sigma (σ), in the commercially available austenitic stainless steel wire feedstocks 316L, 316LSi, 316H and 16-8-2. All WA-DED samples formed secondary phases at grain boundaries (likely σ, possibly other phases as well), but these phases caused negligible changes in tensile properties in 316L, 316LSi and 316H. Samples of 16-8-2 formed significant amounts of ferrite and/or martensite after aging, which increased tensile strength but reduced ductility when tested at room temperature. This work demonstrates the need to design feedstock compositions that are stable with respect to ferrite and/or martensite formation, in addition to phases typically associated with embrittlement, to ensure microstructure and mechanical property stability for high-temperature applications with long service lives.

 

‘Algorithms’ is a core CS concept included in the K-12 CS standards, yet student challenges with understanding different aspects of algorithms are still not well documented, especially for younger students. This paper describes an approach to decompose the broad middle-school ‘algorithms’ standard into finer grained learning targets, develop formative assessment tasks aligned with the learning targets, and use the tasks to explore student understanding of, and challenges with, the various aspects of the standard. We present a number of student challenges revealed by our analysis of student responses to a set of standards-aligned formative assessment tasks and discuss how teachers and researchers interpreted student responses differently, even when using the same rubrics. Our study underscores the importance of carefully designed standards-aligned formative assessment tasks for monitoring student progress and demonstrates the need for teacher content knowledge to effectively use formative assessments during CS instruction. 

This poster presents findings on middle school students’ understanding of core Computer Science (CS) concepts, such as variables and control structures, using cognitive think-aloud interviews with eight students. Each student worked on 16-22 formative assessment tasks designed to assess understanding on the ‘Algorithms and Programming’ middle school CS standards. Our study describes students’ interpretations of the CS concepts and discusses potential factors influencing student interpretations. Significance and next steps are described.