177 research outputs found

    MCDIT 21 - A computer code for one-dimensional elastic wave problems

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    Computer program for one dimensional elastic wave problems connected with structural member

    Analytical study of the fracture of liquid- filled tanks impacted by hypervelocity particles

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    Shock waves in water and stress waves in tank walls of water-filled fuel tanks impacted by hypervelocity particle

    Robotic apparatuses, systems and methods

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    A mobile device for traversing a ferromagnetic surface. The device includes a frame and at least one surface contacting device attached to the frame. The device also includes a Halbach magnet array attached to the frame, wherein the Halbach magnet array provides a magnetic force to maintain the surface contacting device substantially into contact with the ferromagnetic surface

    A Capstone Project on Robust Dynamic Positioning and Data Acquisition Systems

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    The United States Coast Guard is responsible for enforcing Dynamic Positioning System (DPS) standards in the maritime industry. It is important for the members of the U. S. Coast Guard to understand how these systems work. Students have gained a much greater understanding of how DPS platforms work and what might be required to maintain them by building one from scratch. Aside from this, the project has served as a great opportunity to work on a one year term project that may resemble engineering or acquisitions projects that might be encountered in the students’ future careers. The overall goal of the Robust Dynamic Positioning and Data Acquisition System project was to prototype a dynamic positioning system similar to the ones on buoy tenders in the fleet. The primary goal was to maintain a desired heading and position within a certain range. The secondary goals included robust capabilities (the ability to continue functioning despite motor failures) and data acquisition (to analyze system performance post-testing). Students built a vessel from scratch out of a salvage drum and an inner tube for buoyancy. The internal construction consists of three tiers containing batteries at the lowest level, an onboard computer at the second level, and control hardware at the top level (micro controllers, H-bridges, and fuse boxes). Students successfully used a light detection and ranging (LIDAR) device to determine the relative position to two stationary poles. They were able to communicate with the onboard computer via either a wired connection or a remote desktop connection through an ad-hoc wireless network. All programming for this project was done in MATLAB®. Students have completed all project milestones through the application of past courses they have taken in computer control systems, network communication, and digital signal processing at the U.S. Coast Guard Academy. The first challenge of this project was to focus on constructing the vessel and installing the control hardware. One of the obstacles for the students was establishing communication between the various pieces of software, hardware, and the power distribution system. The LIDAR sensor determined the vessel’s relative position and heading to two stationary poles. Using the position and heading resolution algorithms, students conducted a set of system identification tests in an indoor tank to determine how the system reacts to various thrusts from the motors. This allowed students to collect “Open-Loop” system data. Using the data acquisition system, students were able to identify the system and calculate coefficients for the controller and implement a “Closed- Loop” control system. Students successfully implemented a proportional integral derivative (PID) controller that satisfies all design requirements including robust functionality. Currently, all milestones for the project have been accomplished and plans for continuation of the project are underway

    Feasibility of Electrified Propulsion for Ultra-Efficient Commercial Aircraft Final Report

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    MIT, Aurora Flight Sciences, and USC have collaborated to assess the feasibility of electric, hybridelectric, and turbo-electric propulsion for ultra-efficient commercial transportation. The work has drawn on the team expertise in disciplines related to aircraft design, propulsion-airframe integration, electric machines and systems, engineering system design, and optimization. A parametric trade space analysis has been carried out to assess vehicle performance across a range of transport missions and propulsion architectures to establish how electrified propulsion systems scale. An optimization approach to vehicle conceptual design modeling was taken to enable rapid multidisciplinary design space exploration and sensitivity analysis. The results of the analysis indicate vehicle aero-propulsive integration benefits enabled by electrification are required to offset the increased weight and loss associated with the electric system and achieve enhanced performance; the report describes the conceptual configurations than can offer such enhancements. The main contribution of the present work is the definition of electric vehicle design attributes for potential efficiency improvements at different scales. Based on these results, key areas for future research are identified, and extensions to the trade space analysis suitable for higher fidelity electrified commercial aircraft design and analysis have been developed

    Geographic Variation Within the Military Health System

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    Background: This study seeks to quantify variation in healthcare utilization and per capita costs using system-defined geographic regions based on enrollee residence within the Military Health System (MHS). Methods: Data for fiscal years 2007 – 2010 were obtained from the Military Health System under a data sharing agreement with the Defense Health Agency (DHA). DHA manages all aspects of the Department of Defense Military Health System, including TRICARE. Adjusted rates were calculated for per capita costs and for two procedures with high interest to the MHS- back surgery and Cesarean sections for TRICARE Prime and Plus enrollees. Coefficients of variation (CoV) and interquartile ranges (IQR) were calculated and analyzed using residence catchment area as the geographic unit. Catchment areas anchored by a Military Treatment Facility (MTF) were compared to catchment areas not anchored by a MTF. Results: Variation, as measured by CoV, was 0.37 for back surgery and 0.13 for C-sections in FY 2010- comparable to rates documented in other healthcare systems. The 2010 CoV (and average cost) for per capita costs was 0.26 ($3,479.51). Procedure rates were generally lower and CoVs higher in regions anchored by a MTF compared with regions not anchored by a MTF, based on both system-wide comparisons and comparisons of neighboring areas. Conclusions: In spite of its centrally managed system and relatively healthy beneficiaries with very robust health benefits, the MHS is not immune to unexplained variation in utilization and cost of healthcare

    Novel M4 Pediatrics Chief Program Utilizing Near-peer Teaching and Mentoring to Enhance Clerkship Curricula

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    Introduction: Near-peer teachers add many benefits to the academic, clinical performance, and enjoyment of near-peer learners in medical education. This enterprise describes and examines how the Creighton University School of Medicine M4 Pediatrics Chief Program fills a gap in medical education by offering an organized and formal methodology for near-peer teaching. The Creighton University M4 Pediatrics Chief Program utilizes select fourth year medical students to orient, teach basic clinical skills, mentor, and participate in curriculum development for the third year Pediatric clerkship students. Methods: Third year students (n=43) in their Pediatrics clerkship from September 2020 to February 2021 completed surveys at the end of the clerkship to assess the quality and effectiveness of the M4 Pediatrics Chief Program. Results: Students rated effectiveness of the Chiefs most highly as clerkship guides (4.29, SD=0.79), teachers (4.21, SD=0.92), and mentors (4.19, SD=0.75). Near-peer perspectives, education, provision of pertinent content, serving as a clerkship resource, and being a source of encouragement were the most beneficial aspects of the program. Students reported strong agreement all clerkships should have an M4 Chief Program (4.53, SD=0.88). Discussion: Because of the positive reviews by the third years students, the M4 Pediatrics Chief Program is now a permanent part of the Pediatric Clerkship. Additionally, other third year clerkships at Creighton University School of Medicine are adopting this model. Finally, the M4 students acting as the chiefs gain valuable leadership and educational skills. Conclusion: Based on positive perceptions of the “M4 Chief Program”, the authors recommend other medical schools consider initiating similar programs within their third year clerkships.https://digitalcommons.unmc.edu/chri_forum/1037/thumbnail.jp
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