Scholars Hangar (United States Air Force Academy)
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Spacecraft Shielding
No full textThe present invention relates to spacecraft shielding, articles comprising such shielding as well as processes of making and using spacecraft shielding and articles comprising such shielding. Such shields are made by a 3D process that provides significant shield geometry and composition flexibility and yields shields that have significantly improved shield performance. Such shields may be efficiently be manufactured in space
A Formal Consideration of User Tactics During Product Evaluation in Early-Stage Product Development
No full textFrequent and effective design evaluation is foundational to the success of any product development effort. Products used, installed or otherwise handled by humans would benefit from an evaluation of the product while formally considering both the physical embodiment of the technology, termed technology, and the steps a user should take to use that technology, termed tactics. Formal and simultaneous evaluations of both technology and tactics are not widespread in the product design literature. Although informal evaluation methods have advantages, formal methods are also known to be effective. In this paper we propose a formal method for evaluating tactics and technology simultaneously. Unlike the published literature, this evaluation involves explicitly defined tactics in the form of a written description of the
actor, environment and series of steps. It also involves the use of stage appropriate, explicitly defined tactics-dependent criteria, which include criteria from a broad range of impact categories
Finger Strengthening Device and Method
No full textA finger strengthening device (FSD) includes a plurality of finger strengthening elements formed therewith. The FSD is attachable to a structure in a plurality of different orientations to permit a variation in finger exercise techniques
User's Manual for GeogridBridge 3.0: A Guide to the Load Displacement Compatibility Method (LDC) for Design of Column-Supported Embankments
No full textSponsored by the Geosynthetics Technical Committee of the Technical Coordination Council of the Geo-Institute of ASCE User's Manual for GeogridBridge 3.0: A Guide to the Load Displacement Compatibility Method (LDC) for Design of Column-Supported Embankments details how to use the GeogridBridge 3.0 (GGB3) spreadsheet, which utilizes the Load Displacement Compatibility (LDC) method for the design of column-supported embankments (CSEs) and walks through two worked examples to illustrate the use of the spreadsheet. This book supplements Theory Manual for the Load Displacement Compatibility Method (LDC) for Design of Column-Supported Embankments, GSP 356, and other geotechnical resources and tools, listed within this manual, to assist engineers with the design and construction of column-supported embankments. Topics include: spreadsheet overview, spreadsheet inputs and outputs, Monte Carlo simulation, and simple and complex worked examples. This manual intends to be an informed, continuously updated guide for geotechnical engineers and engineering professionals looking to incorporate the GGB3 spreadsheet into standard engineering practices regarding the design of column-supported embankments. To access the GeogridBridge spreadsheet, go to https://doi.org/10.17605/OSF.IO/HQRBU. This will redirect to the OSF | GeogridBridge3.0 website.Sponsored by the Geosynthetics Technical Committee of the Technical Coordination Council of the Geo-Institut
Relationships Between Student Self-Assessment Ability and Performance
Full text linkKnowledge surveys (KS) are a self-assessment tool where the questions correspond one-for-one with learning objectives in a course. In response to the KS questions, students select a confidence rating that describes their self-assessed ability to demonstrate understanding or perform a skill. Pre-KS at the beginning of a course or unit of instruction serve as an outline of future learning objectives for students and alert faculty to pre-existing student capabilities. Students can access the KS questions continuously during the unit of instruction as a formative learning guide. Post-KS immediately prior to a summative exam enable comparison of student self-assessments of learning with faculty assessments of student performance.
Fundamental Hydraulics is a junior level fluid mechanics course required for civil engineering majors at a small university in the Western United States. KS were employed in eight sections of Fundamental Hydraulics from Spring 2019 to Spring 2021 with a total student population of 118. Prior research on KS in this course has shown that student self-assessments via KS are well-aligned with their exam scores. Given the data set in this course, we further explored relationships between student performance and their self-assessment abilities.
Results show that the correlation between student KS scores and their grades on each of the three unit exams in the course improves with each successive cycle of performance and feedback. We also examined the self-assessment ability of the student cohort by upper and lower halves of cumulative GPA, measured as of the semester prior to taking Fundamental Hydraulics. These data show that students in the upper half by GPA maintained consistent self-assessment accuracy through the three exams while students in the lower half by GPA improved their selfassessment accuracy by the third exam. Finally, we examined whether student performance improved in conjunction with the improvement in self-assessment accuracy. Although results are mixed as to whether student performance improved in a single semester, the self-assessment skills demonstrated by the entire student cohort, and particularly the improvement shown by the lower half of students by GPA, offers further encouragement that KS are a useful tool to support development of self-assessment skills and student learning
Precipitate Structure, Microstructure Evolution Modeling and Characterization in an Aluminum Alloy 7050 Friction Stir Weld
No full textNovel use of differential scanning calorimetry (DSC), with 1.7 mm specimen spacing intervals across a friction stir weld, coupled with microhardness, electrical conductivity, transmission electron microscopy (TEM), and novel three-dimensional thermal modeling of temperature profiles were used to characterize precipitate structure as a function of position across a friction stir welded and post-weld stabilized aluminum alloy 7050. The results show excellent agreement with predictions of existing FSW microstructural evolution models for 7XXX aluminum alloys. The DSC scans and thermal modeling accurately predicted the locations and peak temperatures at which transitions from 1) slow precipitate dissolution to 2) rapid dissolution, coarsening, and transformation of η′ to η precipitates to 3) increasing η dissolution and matrix supersaturation occur along the weld. These results are correlated to significant changes in the microhardness and electrical conductivity profiles. Following a 12-year period after the initial post-weld stabilization treatment, the closely spaced DSC scans were able to show that the initial stabilization treatment, (a standard T6 heat treatment), had not fully stabilized the weld near the heat affected zone (HAZ) hardness minimum. A 2-step stabilization method is proposed to fully stabilize the material in this region of the weld
Numerical Analysis and Field Validation of Airfield Pavement Responses for the SMART Runway at Hill AFB
No full textMethod of Delivering Repeaters in a Hostile Environment and a Drone Therefor
No full textA drone for delivering plural repeaters in a hostile environment and method of delivering plural repeaters from the drone. The drone is controllable from a remote base station and carries a payload of repeaters on a round tray. The tray has a dispensing hole, complementary to the geometry of the repeater for dispensing the repeaters as needed. Repeaters are consecutively dispensed at stations as determined by an
operator. A central radial arm sweeps each repeater around the tray, in turn, until the hole is encountered and the repeater gravity drops to a surface below. The drone may have two or more vertically stacked trays to increase payload without increasing footprint