Robotics has been advocated as an emerging approach to engaging K-12 students in learning science, technology, engineering, and mathematics (STEM). This study examined the impacts of a project-based STEM integrated robotics curriculum on elementary school students' attitudes toward STEM and perceived learning in an afterschool setting. Three elementary school teachers and 18 fourth to sixth graders participated in an eight-week-long program. Quantitative and qualitative data were collected and analyzed, and showed students' attitudes toward math improved significantly at the end of the robotics curriculum. Three specific areas of learning were identified, including STEM content learning and connection, engagement and perseverance, and development and challenge in teamwork. The findings also identified the opportunities and challenges in designing a STEM integrated robotics afterschool curriculum for upper elementary school students. Implications for future research studies and curriculum design are discussed.

one-third of which can directly be attributed to anthropogenic climate change (Vicedo-Cabrera et al., 2021). Heatwaves, defined as prolonged periods of excessive heat, are becoming more intense, more frequent and longer across many regions of the globe (Nanditha et al., 2020;Perkins et al., 2012) and are expected to further intensify in a warming climate (Li, 2020). Exposure to extreme heat events is also increasing around the world (Batibeniz et al., 2020;Mukherjee et al., 2021;Russo et al., 2015), currently exposing ∼30% of the global population to health-threatening heat

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Clayey soils with medium to high plasticity are prevalent in several parts of the world, causing billions of dollars in damage annually to various civil infrastructures. Several groundimprovement-techniques were employed to counteract this issue. However, these methods are impractical in certain situations and unsustainable in others due to their economic and environmental impacts. Microbial Induced Calcite Precipitation (MICP) could provide a more sustainable alternative. Researchers have successfully used MICP to alter specific geotechnical properties of the sands and silts. This research investigates the applicability of MICP via biostimulation to treat clayey soils with low to high plasticity. The goal is to determine the viability of this technique to alter the engineering behavior of clayey soils, especially given the low permeability of these soils. For this purpose, four soils were selected from four different locations in Idaho and Montana. The soils were selected such that their plasticity varied from low to high to study the effect of plasticity index on the effectiveness of MICP treatments. In addition to the four soils, three additional artificial mixes were studied to study the effect of clay content on MICP effectiveness. Both macro and micro scale studies were conducted on untreated and biostimulated soils to observe strength gain, swelling reduction, calcium carbonate precipitation. The results show that MICP via biostimulation would be a promising method to treat problematic clayey soils.

Expansive soils have long been recognized as problematic because they cause failure to civil structures constructed above them. The main problem of these soils can be attributed to poor understanding of the volume changes caused by moisture fluctuations. Current swell and shrinkage characterization models are limited by both the lack of standardized tests and tests that employ volume changes in uniaxial direction. In the present research, a comprehensive laboratory investigation was undertaken to study the volume change related swell-shrinkage behaviors of five different types of expansive clayey soils sampled from various regions in Texas, USA. Extensive experimental programs consisting of basic, chemical and mineralogical soil properties were first determined. Three-dimensional free swell and shrinkage tests were performed on all soils at various compaction moisture content conditions. Soil water characteristic curves (SWCCs) of all test soils were determined by studying the suction potentials of these soils over a wide range of moisture contents. Volume change measurements of soils showed a good correlation with soil properties, including plasticity and soil compaction properties. SWCC results also showed a clear variation in SWCC profiles of soils with respect to soil plasticity. Overall, a large database of soil properties was developed and is presented here. It includes physical and mineralogical properties, and engineering test results including swell, shrinkage and SWCCs. This is an author-produced, peer-reviewed version of this article. The final, definitive version of this document can be found online at Engineering Geology, published by Elsevier. Copyright restrictions may apply.