Scholars Hangar (United States Air Force Academy)
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A probabilistic approach to assess slope stability of roadway shoulders under superheavy traffic operations
Full text linkNon-conventional Super Heavy Load (SHL) units generally transport heavy loads weighing significantly higher than conventional trucks. Movements of such SHL trailer units with overweight tires and non-generic axle assemblies are detrimental to the structural integrity of sloped roadway shoulders. This research proposes an approach to realistically evaluate stability of roadway shoulders under subjected to SHL units. The developed methodology upgrades conventional Limit Equilibrium Method to a probabilistic approach to consider uncertainties attributed to orthogonal stiffness characteristics of aggregate materials in pavement structures. The proposed novel approach is also capable of assessing complex traffic loads imparted under SHLs. To achieve these objectives, the researchers first developed a field-testing scheme to obtain prominent features associated with the SHL trailer units and their loading configurations, as well as pavement material and road shoulder characteristics for ten overweight corridors in Texas. The field-derived information was then used as inputs in a series of 3D finite element model to characterize SHL-induced forces. Monte-Carlo methods was also deployed to establish a distribution of shear strength factors, within the bounds of laboratory-derived data for base and subbase layers as well as subgrade soils. Eventually, the resisting forces were contrasted with mobilizing forces along failure surfaces to assess stability of pavement shoulders. Results underscored the importance of tire load magnitude, shoulder slope inclination, surface treatment, and moisture management mechanisms in stability studies of roadway shoulders under demanding stress paths in overweight routes. The permutations pertaining to extreme weather events such as flooding, heavy rainfall, and prolonged inundation events also showed the detrimental effect of SHL operations on the stability of sloped shoulders. The proposed approach and synthesized results for Texas SHL corridors provided in this research facilitate realistic evaluation of the potential failure risk of sloped shoulders under SHL operations, considering non-typical nature of SHLs, environmental factors, and unique features of roadway shoulders in such regions
Implementing Technical Communication Instruction in a CE Course: The Value of Knowledge Surveys and Peer Review
Full text linkThere is a growing need for engineers to be effective communicators, yet professional skills are often under-developed by college-level engineering curriculum and undervalued by engineering students. To improve communication skills, we integrated a technical communication block of instruction into a civil engineering computer applications course. Applying strategies from self-regulated learning theory, we used self-assessments to measure effectiveness of the instruction. Specifically, we used pre and post knowledge surveys (KS) that were comprised of competency statements aligned with the learning outcomes for each assignment. We also reviewed students’ scores received on their technical writing assignment submissions. Then, we compared students’ KS assessments against instructor scores on each of the five writing assignments. Overall, the technical communication was deemed effective as demonstrated by improved student technical writing competencies including creating more audience-centered, accessible, and usable deliverables. Results from KS demonstrate self-assessments became better aligned with instructor’s grades, indicating students improved in their ability to self-assess their own capabilities. This study reinforces the benefit of integrating technical communication instruction, even on a small scale, and highlights the usefulness of KS for self-assessment and learning. Recommendations for integrating peer review, both in terms of frequency and type, are also discussed
Student self-assessment data: an instrument for program assessment
Full text linkoai:https://scholarshangar.usafa.edu:20.500.14358/74The ability to assess oneself is important in higher education, on the job, and throughout all aspects of life. Knowledge surveys (KS) are a self-assessment tool where students rate their ability to answer a knowledge question or perform a skills task. Previous research has shown that students are accurate self-assessors compared to instructor assessments when KS questions are specific and well-aligned with learning objectives and course content. Although it has been suggested as a use of KS in the literature, there are few data on the specific use of KS as a part of a continuous improvement process for program assessment. In this case study, KS were implemented in a Fundamentals of Engineering (FE) exam review course at an undergraduate-only civil engineering program in the western U.S. The paper will outline several components of our continuous improvement process, then compare KS with FE exam results from a cohort of students. The comparison demonstrates the utility of student self-assessment data as one artifact that helps to paint a more complete picture for program assessment. In addition, we will present several assessment benefits to implementing KS in courses and throughout an undergraduate program
Geometrical Characteristics of Lunar and Martian Regolith Simulants
No full textConference PaperIn the next decade, NASA is prioritizing Moon missions such as safe human transportation, deployment of instrumentations, establishment of habitats, and exploration of native resources to set the stage for future Mars missions. One of the main challenges to achieve these goals, however, is our lack of understanding of the synergistic interactions between the native soil, lunar vehicles, habitats, and EVA suits. In addition to the particle size distributions, surface properties, and compaction characteristics of the surface regolith, the geometry of the particles is of paramount importance for a proper understanding of the settlement properties, distortion characteristics, and orthogonal strength of the particulate medium, which impacts transportation, habitat development, and the regolith’s potential to degrade EVA suits by abrasion based on the angularity of the particles. Therefore, our multi-disciplinary team in this research envisioned using a state of the art optical profilometer equipment supplemented by image analysis techniques to characterize the geometrical features of a lunar regolith simulant, specifically the CSM-LHT-1 highlands type. The distributions of the particle form, angularity, and surface macro-texture of lunar regolith were in turn contrasted with JSC-1 Mars simulants and a calcareous construction aggregate for comparative purposes in this study. The results will be instrumental to better understand the anisotropic nature of the angular particles and its relevance to the strength and deformation characteristics of native soils on extra-terrestrial planetary surfaces
Exploring Solutions for Container Image Security
Full text linkGuided by NIST’s Application Container Security Guide, we explore workflows to address container image vulnerabilities that have known fixes. The approach stems from the idea that a DevOps team should always build container images that meet a specified security standard. We outline a blueprint that leverages a vulnerability scanner to establish a baseline of security issues and reduces that list via an automated patching process. We target popular images in common use: scanning each image identifies potential vulnerabilities and misconfigurations, and we compare the results of our automated pipeline against both the original image and a manually patched one. Through our work, we identified technical barriers to patching fixable vulnerabilities in off-the-shelf (OTS) images, a lack of accountability for badges used by popular container registries, and that responsibility for container security falls heavily on the shoulders of users
Reminiscence and digital storytelling to improve social and emotional well-being of older adults with ADRD: Protocol of mixed methods study design and a randomized control trial
Full text linkSystem and Method for Disabling Multi-Rotor Aircraft
No full textA drone disabling device includes a plurality of streamer launch tubes having at least one streamer device positioned therein. A barrel housing is configured to hold the plurality of launch tubes within streamer launch barrels. An ignition system is configured to ignite propellant within the launch tubes and launch the streamer devices from the barrel housing such that one or more propellers of a hostile drone will become entangled and disabled. A parachute connected to the streamer device is deployed as the drone descends to protect people and property on the ground and to preserve the drone for intelligence gathering after landing
Work in Progress: Developing a Foundational Engineering Course to Improve Students’ Sense of Belonging and Increase Diversity
Full text linkThis paper addresses the national imperative to promote involvement in science, technology, engineering, and mathematics (STEM) fields across all ethnicities, races, genders, and economic backgrounds. The United States Air Force Academy (USAFA) developed a Diversity, Equity, and Inclusion Strategic Plan in 2021, which includes an objective to increase the participation of students from diverse backgrounds in engineering majors. Additionally, the Accreditation Board of Engineering and Technology recently made a commitment to diversity and is considering changes to curriculum criteria which would require engineering programs to demonstrate a culture of diversity, equity, and inclusion. In alignment with USAFA’s strategic plan and the anticipated accreditation criteria, the authors are developing a new foundational engineering course as one element of an institution-wide effort to improve students’ sense of belonging, make engineering majors more accessible to a wider audience, and ultimately increase diversity among engineering graduates. In addition to exploring best practices from literature and other institutions, this paper describes how the authors conducted surveys and interviews from students that took a summer civil engineering field course, extracted lessons learned, and developed course content for the new foundational engineering course informed by the key findings. The interviews revealed student perceptions of how activities and interactions with instructors and peers affected their self-confidence, skill development, and sense of belonging. The first-year course under development is centered on two features: 1) a problem-based learning approach to spark interest and develop the technical skills necessary for students to be successful in an engineering major, and 2) challenging stereotypes of what types of people do engineering while stimulating a sense of belonging in engineering from students of all backgrounds