USMA Digital Commons (United States Military Academy, West Point)
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Towards a General-Purpose, Replicable, Swarm-Capable Unmanned Aircraft System
No full textThis paper describes an effort to create a general-purpose Unmanned Aircraft System (UAS) swarm using entirely Commercial Off-the-Shelf (COTS) parts and a reusable swarming software architecture. The software architecture used in this research was originally designed for a UAS warfare competition in 2017 called the Service Academies Swarm Challenge (SASC), hosted by the Defense Advanced Research Projects Agency (DARPA). The SASC software is a multipurpose swarm-control software architecture that allows a swarm to be tailored to many different purposes by third-parties. However, the UASs used in the original SASC competition contain custom parts which have begun to deteriorate over years of use. A COTS UAS solution using the SASC swarm architecture is the next step towards expanding the usefulness of the swarm so that it can be deployed, replicated, modified, and generalized to suit many different needs in a variety of sectors to include homeland security and defense
Airborne Delivery of Unmanned Aerial Vehicles wia Joint Precision Airdrop Systems
No full textThe purpose of this project is to provide a technology demonstration of the aerial delivery of cargo-carrying UAVs. This capability will allow small, high-value payloads to be delivered over the same long distances as the traditional airlift and Joint Precision Airdrop System (JPADS) combination with previously unattainable accuracy. A team of undergraduate students at the United States Military Academy accomplished this goal by designing, building, testing, and demonstrating a scale model of a UAV aerial delivery system. The customer for this product is the Aerial Delivery Directorate at Natick Soldier Research Development and Engineering Center, which will expand the scale model prototype into an operational system. The system leverages the existing technologies of JPADS and GPS-enabled multi-rotors and combines them to create the airdrop method of the future. The operational system will have the capability to deliver a 5-15 lb. payload to within 5 meters of the target location. This will enable effective resupply of individuals or troops in contact, who could pick up an airdrop without having to leave cover
Defeating Ambiguity: Modeling Problems with Calculus
Get PDFMany first year calculus students struggle to see the value in learning single variable calculus. They often focus their efforts on learning the rules of differentiation and integration, losing sight of the broader picture for how calculus is leveraged to solve problems. While rudimentary calculus problems are necessary for the sake of understanding basic rules and concepts, larger and more complex problems are critical to opening the doors for students to gain a practical understanding of the applications. Through a series of Problem Solving Labs and written reports, the single variable calculus program at West Point not only focuses on learning calculus, but also how the core concepts can be used to conduct quantitative analysis that can be communicated to decision makers. Throughout the semester-long course, single variable calculus students complete 4 to 5 different Problem Solving Labs where they leverage technological tools such as excel and mathematica to develop mathematical models to formulate overall recommendations. Each lab report prompt is designed to present an ambiguous problem that requires critical assumptions to enable mathematical modeling.https://digitalcommons.usmalibrary.org/presentations/1006/thumbnail.jp
Effect of different doses of supervised exercise on food intake, metabolism, and non-exercise physical activity: The E-MECHANIC randomized controlled trial.
No full textBACKGROUND: Exercise is recommended for weight management, yet exercise produces less weight loss than expected, which is called weight compensation. The mechanisms for weight compensation are unclear.
OBJECTIVE: The aim of this study was to identify the mechanisms responsible for compensation.
METHODS: In a randomized controlled trial conducted at an academic research center, adults (n = 198) with overweight or obesity were randomized for 24 wk to a no-exercise control group or 1 of 2 supervised exercise groups: 8 kcal/kg of body weight/wk (KKW) or 20 KKW. Outcome assessment occurred at weeks 0 and 24. Energy intake, activity, and resting metabolic rate (RMR) were measured with doubly labeled water (DLW; with and without adjustments for change in RMR), armband accelerometers, and indirect calorimetry, respectively. Appetite and compensatory health beliefs were measured by self-report.
RESULTS: A per-protocol analysis included 171 participants (72.5% women; mean ± SD baseline body mass index: 31.5 ± 4.7 kg/m2). Significant (P \u3c 0.01) compensation occurred in the 8 KKW (mean: 1.5 kg; 95% CI: 0.9, 2.2 kg) and 20 KKW (mean: 2.7 kg; 95% CI: 2.0, 3.5 kg) groups, and compensation differed significantly between the exercise groups (P = 0.01). Energy intake by adjusted DLW increased significantly (P \u3c 0.05) in the 8 KKW (mean: 90.7 kcal/d; 95% CI: 35.1, 146.4 kcal/d) and 20 KKW (mean: 123.6 kcal/d; 95% CI: 64.5, 182.7 kcal/d) groups compared with control (mean: -2.3 kcal/d; 95% CI: -58.0, 53.5 kcal/d). Results were similar without DLW adjustment. RMR and physical activity (excluding structured exercise) did not differentially change among the 3 groups. Participants with higher compared with lower compensation reported increased appetite ratings and beliefs that healthy behaviors can compensate for unhealthy behaviors. Furthermore, they increased craving for sweet foods, increased sleep disturbance, and had worsening bodily pain.
CONCLUSIONS: Compensation resulted from increased energy intake and concomitant increases in appetite, which can be treated with dietary or pharmacological interventions. Compensation was not due to activity or metabolic changes. This trial was registered at clinicaltrials.gov as NCT01264406
The Critical Pick: A Crane Rigging Demonstration
Get PDFThis demonstration, an application of static equilibrium and geometry knowledge, depicts the importance of rigging angles during crane lift operations on a construction site. Reducing rigging angles results in a significant amplification of forces in the rigging, potentially leading to failure. By varying the connection points and sling length, students will be able to calculate the predicted forces and analyze the best combination of connection points and sling lengths to successfully complete the critical lift. The forces in rigging (sling, chain, wire rope, webbing, shackles, etc.) increase substantially as the angle formed by the sling leg and the horizontal datum becomes smaller. The key engineering principle with this emonstration is related to an understanding of statics. Students must comprehend that decreasing the angle creates a horizontal force component that increases the tension in the rigging. The demonstration takes 15-20 minutes to complete in class
A geospatial information science analysis of soil lead levels at West Point, New York
No full textWest Point is the oldest continuously operated military post in the United States with fortifications designed as early as 1778. Along with fortification designed as early as 1778, various residential areas emerged during six distinct periods of growth ranging from 1819 to 2010. The composition of construction materials and consumer products has changed over this time period with respect to lead based paint and leaded gasoline. In the United States, it is common for urban soils to have lead levels greater than the general background level of 50 mg kg-1. The objective of this study was to correlate the lead concentration in soil with the six distinct periods of residential development. A total of 80 samples were collected and analyzed using inductively coupled plasma arc emissions spectroscopy to determine lead concentration in the soil. Initial results indicated statistically significant results related to age of construction of residences and the concentration of lead in the soil. Integration of geo-referenced lead concentrations into ArcGIS enabled visual representation of a heat map correlating age of construction and lead concentration. The predictive ability to determine soil lead levels based upon age of construction over a 240 year period has application for identification of potential areas exceeding lead concentrations in neighborhoods across the country where historic residences remain
Long-term Impact on Environmental Attitudes and Knowledge Assessed over Three Semesters of an Environmental Engineering Sequence
No full textThe pedagogy employed in a three-course environmental engineering sequence is investigated to determine the efficacy of enabling long-term improvement of knowledge and attitudes toward the environment. These three courses incorporate concepts of the five grand challenges released by the National Academy of Engineering and National Academy of Sciences and increase the breadth of knowledge for T-professionals. Previous studies of lengths from a few weeks to semester long courses evaluated the potential causality among various demographics and environmental knowledge and attitudes. The research presented herein contrasts and compares changes in environmental knowledge based upon a 12-question survey and changes in environmental attitude based upon a seven-question survey administered at the beginning and end of the environmental engineering sequence courses taught to over 200 students from a variety of disciplines. Survey results demonstrate that a positive increase (9.27%) in knowledge occurred from the start to the end of the first course and the elimination of statistical differences among numerous demographics such as sex and race. After 18 months of environmental education, an 8.6% increase in knowledge was retained compared to the initial knowledge where the female and non-white demographics increased the most but retained the least. Results regarding environmental attitudes suggest that a focus on learning about environmental issues decreased positive attitudes toward the environment, whereas focusing on solutions to environmental issues increased positive attitudes toward the environment. Evaluating changes or sustainment of improved environmental attitudes over three semesters demonstrates the potential for an environmental engineering education to have a multi-year impact on the values and environmental ethos of students across many disciplines
Three Dimensional Velocity And Temperature Field Measurements Of Internal And External Turbine Blade Features Using Magnetic Resonance Thermometry
No full textMagnetic resonance thermometry (MRT) is a maturing diagnostic tool used to measure three-dimensional temperature fields. It has a great potential for investigating fluid flows within complex geometries leveraging medical grade magnetic resonance imaging (MRI) equipment and software along with novel measurement techniques. The efficacy of the method in engineering applications increases when coupled with other well-established MRI-based techniques such as magnetic resonance velocimetry (MRV). In this study, a challenging geometry is presented with the direct application to a complex gas turbine blade cooling scheme. Turbulent external flow with a Reynolds number of 136,000 passes a hollowed NACA-0012 airfoil with internal cooling features. Inserts within the airfoil, fed by a second flow line with an average temperature difference of 30 K from the main flow and a temperature-dependent Reynolds number in excess of 1,800, produces a conjugate heat transfer scenario including impingement cooling on the inside surface of the airfoil. The airfoil cooling scheme also includes zonal recirculation, surface film cooling, and trailing edge ejection features. The entire airfoil surface is constructed of a stereolithography resin—Accura 60—with low thermal conductivity. The three-dimensional internal and external velocity field is measured using an MRV. The fluid temperature field is measured within and outside of the airfoil with an MRT, and the results are compared with a computational fluid dynamics (CFD) solution to assess the current state of the art for combined MRV/MRT techniques for investigating these complex internal and external flows. The accompanying CFD analysis provides a prediction of the velocity and temperature fields, allowing for errors in the MRT technique to be estimated
Obesity Tissue: Composition, Energy Expenditure, and Energy Content in Adult Humans
No full textOBJECTIVE: Chronic positive energy balance leads to obesity, and the excess weight is usually described as consisting solely of adipose tissue (AT) or its two components, fat and fat-free mass (nonfat cell mass, extracellular fluid). This study aimed to clarify the nature of obesity tissue.
METHODS: A total of 333 adults had AT, skin, skeletal muscle, bone, heart, liver, kidney, spleen, brain, and residual mass measured or derived using magnetic resonance imaging and dual-energy x-ray absorptiometry. First, associations between these components and AT were examined by developing multiple regression models. Next, obesity-tissue composition was developed by deriving mean component mass differences between participant groups with normal weight (BMI \u3c 25 kg/m
RESULTS: AT significantly predicted organ-tissue mass in 17 of 18 multiple regression models. In addition to AT and skeletal muscle, the following associations were found: skin, liver, and bone were main contributors to obesity-tissue composition; liver, kidneys, and heart to resting energy expenditure; and skin, liver, and bone to metabolizable energy and protein contents. A pronounced sexual dimorphism was present in all three models.
CONCLUSIONS: Obesity is characterized not only by excess AT but by increases in the masses of other companion organs and tissues and their related metabolic properties
Design and Implementation of a New Retrofit for Prestressed Concrete Bridge Elements Using Mechanically-Fastened Fiber-Reinforced Polymer
No full textCurrently, departments of transportation (DOTs) must post load restrictions or closures on bridges with deteriorated prestressed concrete superstructures that can no longer carry original design loads. These posted restrictions and closures result in detours that increase travel time and vehicle operating costs for detoured vehicles, impacting commerce, public transportation, and emergency services. Often, load restrictions and closures must remain in place for several years to allow for budgeting, design, and contracting cycles prior to scheduling and completion of permanent repairs or superstructure replacement which must occur to remove posted restrictions. A retrofit solution, which is capable of restoring prestress losses and strength reduction in mild to moderately deteriorated prestressed concrete bridge superstructures such that the useful service life of the bridge can be extended for 3 to 5 years allowing a more permanent solution to be planned and budgeted, would be useful. A practical retrofit alternative is one that that can be installed relatively rapidly by DOT maintenance personnel, can immediately restore traffic upon installation, can be easily inspected and maintained as necessary, and should not be more costly than user costs associated with load restrictions or closures. The thesis describes the results of an experimental program to examine the practical and technical feasibility of restoring prestress losses in deteriorated prestressed concrete C-channel beams using a mechanically-fastened fiber-reinforced polymer (MF-FRP) retrofit methodology. This study found that the developed MF-FRP retrofit methodology is capable of restoring the original bridge load rating and can be installed by a single DOT maintenance crew within 1 to 2 days, depending upon the length and level of deterioration of the candidate bridge. Small-scale testing to optimize the mechanical anchor pattern with respect to the capacity of the FRP material was examined and the number of fasteners required for a typical application was determined. A prestressing mechanism for the retrofit and connection design to attach the MF-FRP retrofit system was developed, including effects of the significant spatial restrictions found in the field. The methodology was optimized with respect to FRP efficiency and retrofit installation time. The MFFRP retrofit solution was tested on 6 full-scale prestressed concrete C-channel beams recently removed from service. The full-scale tests examined the behavior of the undamaged (control) and deteriorated beams with and without the MF-FRP retrofit. The results of the full-scale tests indicated that the MF-FRP retrofit solution presented in this study is capable of restoring the original load rating of prestressed concrete C-channel beams with mild to moderate prestress loss due to deterioration, and it is feasible for the MF-FRP retrofit to be rapidly installed on-site on a bridge and immediately restore traffic upon installation. Technical limitations and difficulties with field installation techniques used in the initial design resulted in significant changes in both the design and field-fabrication methods. Basic production rates for the initial and improved designs were determined, confirming that the field installation can be completed in as little as a single work day by a typical 4-worker DOT maintenance crew. Additionally, a limited qualitative cost comparison indicates that the proposed MF-FRP methodology is economically feasible with the break-even point between the initial installation and material cost to the DOT and the vehicle operating cost savings occurring between a few days and a few months, depending upon the traffic volume, detour length, and posted restriction level for a deteriorated bridge