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Articles 361 - 390 of 1156
Full-Text Articles in Engineering
Parameterized Vertical-Axis Wind Turbine Wake Model Using Cfd Vorticity Data, Andrew Ning, Eric Tingey
Parameterized Vertical-Axis Wind Turbine Wake Model Using Cfd Vorticity Data, Andrew Ning, Eric Tingey
Faculty Publications
In order to analyze or optimize a wind farm layout, reduced-order wake models are often used to estimate the interactions between turbines. While many such models exist for horizontal-axis wind turbines, for vertical-axis wind turbines (VAWTs) a simple parametric wake model does not exist. Using computational fluid dynamic (CFD) simulations we computed vorticity in a VAWT wake, and parameterized the data based on normalized downstream positions, tip-speed ratio, and solidity to predict a normalized wake velocity deficit. When compared to CFD, which takes about a day to run one simulation, the reduced-order model predicts the velocity deficit at any location …
Landing Zone Determination For Autonomous Rotorcraft In Surveillance Applications, Timothy Mclain, Gary J. Ellingson, Justin Mackay
Landing Zone Determination For Autonomous Rotorcraft In Surveillance Applications, Timothy Mclain, Gary J. Ellingson, Justin Mackay
Faculty Publications
This paper presents an approach for finding possible landing sites for a rotorcraft from an inertially referenced point-cloud model of the environment. To identify potential landing sites that are suitably flat and level, a grid-based random sample consensus algorithm separates the terrain map into discrete areas for plane-fitting analysis. Landing sites are selected that satisfy constraints on flatness and levelness while optimizing the surveillance target’s visibility. Flight test results are presented from a small multirotor aircraft flying over a scale-model cityscape. Results from real-time landing-site experiments are presented and discussed.
Effects Of Various Mobility Aids On Lower-Extremity Muscle Activity, Michael Ryan Sanders
Effects Of Various Mobility Aids On Lower-Extremity Muscle Activity, Michael Ryan Sanders
Theses and Dissertations
Millions of people each year spend some portion of their time using mobility aids to facilitate periods of non-weight bearing ambulation. The use of these devices changes the loading conditions of the lower extremities, which may result in skeletal muscle adaptations. The purpose of this work was to evaluate the effects of 3 types of mobility aids on lower-extremity muscle activity. Evaluation was based on 1) measured muscle activation signals using electromyography (EMG), and 2) measured joint kinematics and ground reaction forces, which were used to predict muscle forces. 16 healthy subjects (7 female, 9 male), ages 18-27 participated in …
Elucidating The Mechanisms Of Rate-Dependent Deformation At Ambient Temperatures In A Model Metallic Glass, Matthew Bradley Harris
Elucidating The Mechanisms Of Rate-Dependent Deformation At Ambient Temperatures In A Model Metallic Glass, Matthew Bradley Harris
Theses and Dissertations
In this work, the Shear Transformation Zone (STZ) dynamics model is adapted to capture the transitions between different regimes of flow serration in the deformation map of metallic glass. This was accomplished by scaling the STZ volume with a log-linear fit to the strain rate, and also adjusting the activation energy of an STZ with a log-linear fit to maintain constant yield strength at differing strain rates. Twelve simulations are run at each of six different strain rates ranging from 10-5 to 100 s-1, and statistics are collected on simulation behavior and shear band nucleation and …
Springback Force Considerations In Compliant Haptic Interfaces, Dallin R. Swiss
Springback Force Considerations In Compliant Haptic Interfaces, Dallin R. Swiss
Theses and Dissertations
This thesis investigates the potential benefits and challenges of using compliant mechanisms in the design of haptic interfaces. The benefits and challenges are presented with an emphasis on their inherent springback behavior and an active compensation approach. Design criteria for compliant mechanism joint candidates are reviewed and several joints are surveyed. Quantitative calculations of axial stiffness and maximum stress for five candidates are presented. Generalized analytical models of springback force and compensation torque are created to simulate the implementation of each joint candidate in a two degree-of-freedom planar pantograph. We use these models in the development and discussion of an …
Springback Force Considerations In Compliant Haptic Interfaces, Dallin R. Swiss
Springback Force Considerations In Compliant Haptic Interfaces, Dallin R. Swiss
Theses and Dissertations
This thesis investigates the potential benefits and challenges of using compliant mechanisms in the design of haptic interfaces. The benefits and challenges are presented with an emphasis on their inherent springback behavior and an active compensation approach. Design criteria for compliant mechanism joint candidates are reviewed and several joints are surveyed. Quantitative calculations of axial stiffness and maximum stress for five candidates are presented. Generalized analytical models of springback force and compensation torque are created to simulate the implementation of each joint candidate in a two degree-of-freedom planar pantograph. We use these models in the development and discussion of an …
Aerodynamic Improvement Of The Byu Supermileage Vehicle, Sayan Dobronsky
Aerodynamic Improvement Of The Byu Supermileage Vehicle, Sayan Dobronsky
Theses and Dissertations
The purpose of this thesis work was to design a new shape for the BYU Supermileage vehicle in order to improve its fuel efficiency. Computational Fluid Dynamics (CFD) was used to obtain the coefficient of drag (CD) and drag area of the current baseline vehicle at a Reynolds number of 1.6x10^6 and 8.7x10^5. Then a new shape was developed using mesh morphing software. The new shape was imported into the CFD program and the drag figures and airflow plots from the modified design were compared with the baseline vehicle. Scale models of the vehicles were also printed using a 3D …
Design And Manufacture Of Mesoscale Robot-Actuated Surgical Instruments, Clayton L. Grames
Design And Manufacture Of Mesoscale Robot-Actuated Surgical Instruments, Clayton L. Grames
Theses and Dissertations
Minimally Invasive Surgery (MIS) is a growing field including both laparoscopic androbotic operations. Surgeons and engineers are making continual efforts to reduce the negative effects of procedures on patients. Reducing the size of the surgical instruments is one effective method pursued in this effort. When the instruments approach 3 mm in diameter, they reach a threshold where the entry incisions can be small enough that no scar is left on the patient. Laparoscopic instruments on this scale exist but typically lack wrist articulation and only have 1 degree of freedom (DoF). Alternatively, robotic surgical instruments can achieve high levels of …
Design And Validation Of A Complex Loading Whole Spinal Segment Bioreactor, Amanda Marie Beatty
Design And Validation Of A Complex Loading Whole Spinal Segment Bioreactor, Amanda Marie Beatty
Theses and Dissertations
Intervertebral disc (IVD) degeneration is a prevalent health problem that is highly linked to back pain. To understand the disease and tissue response to therapies, ex-vivo whole IVD organ culture systems have recently been introduced. The goal of this study was to develop and validate a whole spinal segment culturing system that loads the disc in complex loading similar to the in-vivo condition, while preserving the adjacent endplates and vertebral bodies. The complex loading applied to the spinal segment was achieved with three pneumatic cylinders. The pneumatic cylinders were rigidly attached to two triangular alumni plates at each corner, comprising …
Using Star-Ccm+ To Evaluate Multi-User Collaboration In Cfd, Kasey Johnson Webster
Using Star-Ccm+ To Evaluate Multi-User Collaboration In Cfd, Kasey Johnson Webster
Theses and Dissertations
The client-server architecture of STAR-CCM+ allows multiple users to collaborate on a simulation set-up. The effectiveness of collaboration with this architecture is tested and evaluated on five models. The testing of these models is a start to finish set-up of an entire simulation excluding computational time for generating mesh and solving the solution. The different models have distinct differences which test every operation that would be used in a general CFD simulation. These tests focus on reducing the time spent preparing the geometry to be meshed, including setting up for a conformal mesh between multiple regions in conjugate heat transfer …
Rigidly Foldable Origami Gadgets And Tessellations, Thomas A. Evans, Robert J. Lang, Spencer P. Magleby, Larry L. Howell
Rigidly Foldable Origami Gadgets And Tessellations, Thomas A. Evans, Robert J. Lang, Spencer P. Magleby, Larry L. Howell
Faculty Publications
Rigidly foldable origami allows for motion where all deflection occurs at the crease lines and facilitates the application of origami in materials other than paper. In this paper, we use a recently discovered method for determining rigid foldability to identify existing flat-foldable rigidly foldable tessellations, which are also categorized. We introduce rigidly foldable origami gadgets which may be used to modify existing tessellations or to create new tessellations. Several modified and new rigidly foldable tessellations are presented.
An Approach For Designing Origami-Adapted Products With Aerospace Mechanism Examples, Jessica Morgan
An Approach For Designing Origami-Adapted Products With Aerospace Mechanism Examples, Jessica Morgan
Theses and Dissertations
The objective of this research is to develop a design process for origami-adapted products and demonstrate it using aerospace mechanism examples. Origami-adapted design is a type of origami-based design. Origami-based design ranges from abstract to concrete applications of origami to design and includes: origami-inspired design, origami-adapted design, and origami-applied design. Origami-adapted design adapts origami fold patterns into products while preserving functionality. Some of the desirable attributes of origami that are sought after in design include: 1) reduced number of parts, 2) stowability, 3) deployability, 4) transportability, 5) manufacturability from a flat sheet of material, 6) ease of miniaturization, 7) a …
Neutral Parametric Canonical Form For 2d And 3d Wireframe Cad Geometry, Robert Steven Freeman
Neutral Parametric Canonical Form For 2d And 3d Wireframe Cad Geometry, Robert Steven Freeman
Theses and Dissertations
The challenge of interoperability is to retain model integrity when different software applications exchange and interpret model data. Transferring CAD data between heterogeneous CAD systems is a challenge because of differences in feature representation. A study by the National Institute for Standards and Technology (NIST) performed in 1999 made a conservative estimate that inadequate interoperability in the automotive industry costs them $1 billion per year. One critical part of eliminating the high costs due to poor interoperability is a neutral format between heterogeneous CAD systems. An effective neutral CAD format should include a current-state data store, be associative, include the …
Improving The Suction Performance And Stability Of An Inducer With An Integrated Inlet Cover Bleed System Known As A Stability Control Device, Ryan K. Lundgreen
Improving The Suction Performance And Stability Of An Inducer With An Integrated Inlet Cover Bleed System Known As A Stability Control Device, Ryan K. Lundgreen
Theses and Dissertations
The performance of an inducer with the integration of an inlet cover bleed system known as a stability control device (SCD) is investigated using computational fluid dynamics. Inducers are the first stage of high suction performance pumps and are designed to operate under cavitating conditions. Improvements in design have allowed inducers to operate stably with low inlet head conditions, however, cavitation instabilities ultimately lead to pump failure. It has been shown that inducers that employ an SCD fully suppress cavitation instabilities.The performance of an inducer is explored at both on- and off-design flow coefficients, where the flow coefficient is a …
Jet And Droplet Impingement On Superhydrophobic Surfaces, Jonathan Glenn Stoddard
Jet And Droplet Impingement On Superhydrophobic Surfaces, Jonathan Glenn Stoddard
Theses and Dissertations
The effect of superhydrophobicity on liquid water impingement on a flat horizontal surface was explored. The surfaces combined a hydrophobic surface chemistry with a patterned microstucture in order to produce high contact angles with water. Three sets of experiments were performed, one for jet impingement and two for droplet impingement, which advance previous work in characterizing the interaction of water and superhydrophobic surfaces.Jet impingement experiments were performed to characterize a transitional regime between an unsubmerged and a completely submerged superhydrophobic surface by varying an imposed downstream depth. For low downstream depths, the surface remained unsubmerged and displayed only break up …
Effect Of Airfoil And Composite Layer Thicknesses On An Aerostructural Blade Optimization For Wind Turbines, Ryan Barrett, Ian Freeman, Andrew Ning
Effect Of Airfoil And Composite Layer Thicknesses On An Aerostructural Blade Optimization For Wind Turbines, Ryan Barrett, Ian Freeman, Andrew Ning
Faculty Publications
The purpose of this research is to enhance the performance of wind turbine blades by exploring the effect of adding airfoil and material layer thicknesses to the optimization design process. This is accomplished by performing an aerostructural blade optimization to minimize mass over annual energy production and thereby reduce the cost of energy. Changing airfoil thickness allows the airfoil shape to evolve as part of the optimization. The airfoil thicknesses are allowed to vary within two airfoil families, the TU-Delft and NACA 64-series, that are used in the NREL 5-MW reference turbine. Both experimental wind tunnel and computational data are …
Geometry And Material Properties Of Vocal Fold Models, Kimberly Ann Stevens
Geometry And Material Properties Of Vocal Fold Models, Kimberly Ann Stevens
Theses and Dissertations
Voiced communication plays a fundamental role in society. Voice research seeks to improve understanding of the fundamental physics governing voice production, with the eventual goal of improving methods to diagnose and treat voice disorders. For this thesis, three different aspects of voice production research were studied. First, porcine vocal fold medial surface geometry was determined, and the three-dimensional geometric distortion induced by freezing the larynx, especially in the region of the vocal folds, was quantified. It was found that porcine vocal folds are qualitatively geometrically similar to canine and human vocal folds, as well as commonly used models, and that …
Composition Based Modaling Of Silicone Nano-Composite Strain Gauges, Daniel Alexander Baradoy
Composition Based Modaling Of Silicone Nano-Composite Strain Gauges, Daniel Alexander Baradoy
Theses and Dissertations
In this work a review of the technology surrounding high deflection strain sensing with an emphasis on that of a recently developed nickel nano-composite strain sensor is presented. A new base silicone material was identified for the nickel nano-composite strain sensor that improves its mechanical stiffness and conductive properties. A previously identified cyclic creep concern was mitigated through preconditioning and the use of adhered backing materials. Through a block design experiment the strain/resistance curves for the strain sensors were characterized over a wide range of nano-filler material compositions. An analytical model was developed based on observation that the resistance of …
Temperature Measurement Using Infrared Spectral Band Emissions From H2o, Daniel Jared Ellis
Temperature Measurement Using Infrared Spectral Band Emissions From H2o, Daniel Jared Ellis
Theses and Dissertations
Currently there is no known method for accurately measuring the temperature of the gas phase of combustion products within a solid fuel flame. The industry standard is a suction pyrometer and thermocouple which is intrusive, both spatially and temporally averaging, and difficult to use. In this work a new method utilizing the spectral emission from water vapor is investigated through modeling and experimental measurements. This method was demonstrated along a 0.75m line of sight, averaged over 1 minute in the products of a natural gas flame but has the potential to produce a spatial resolution on the order of 5 …
Transport Enhancement Of Rate-Limited Chemical Reactions Via Pt-Decorated, Carbon Nanotube Microarray Membranes, Kevin M. Marr
Transport Enhancement Of Rate-Limited Chemical Reactions Via Pt-Decorated, Carbon Nanotube Microarray Membranes, Kevin M. Marr
Theses and Dissertations
Rate limited chemical reactions can be enhanced by improving the mass transport of the suspended analyte to the catalytic (or electrocatalytic) surface. While many attempts have been made to enhance this mass transport, these approaches are limited to utilizing only two enhancement methods – increasing available catalytic surface area, and increasing the flow of analyte in solution. Flow through high aspect ratio microstructures, however, would provide additional mass transport enhancement via boundary layer confinement. Platinum functionalized carbon nanotube microarray membranes (Pt-CNT-MMs) offer enhanced mass transport via all three methods, and were fabricated for demonstration in a H2O2 sample system, for …
Comparison Of Two Wake Models For Use In Gradient-Based Wind Farm Layout Optimization, Jared Thomas, Eric Tingey, Andrew Ning
Comparison Of Two Wake Models For Use In Gradient-Based Wind Farm Layout Optimization, Jared Thomas, Eric Tingey, Andrew Ning
Faculty Publications
Wind farm layout has a significant impact on the productivity of a wind farm. To ensure that the turbines are placed in the most advantageous arrangement, optimization algorithms are often used during the layout design process. Depending on the wake model used for the optimization, optimizing the layout can be time intensive or potentially inaccurate. In this paper we present a comparison of optimization results using two simple wake models, the FLORIS model and the Jensen model. Results highlight some of the key similarities and differences of layout optimization results when different wake models are used.
Wind Farm Layout Optimization Using Sound Pressure Level Constraints, Eric Tingey, Jared Thomas, Andrew Ning
Wind Farm Layout Optimization Using Sound Pressure Level Constraints, Eric Tingey, Jared Thomas, Andrew Ning
Faculty Publications
This project explored wind farm layout optimization using turbine acoustic and wake models. For two existing wind farms, the position of each wind turbine was optimized to maximize power output while constraining noise. Semi-empirical calculations were used for both the acoustic and wake models to predict how the turbine noise and wake disturbances propagated downstream. Turbine layout was optimized using a sequential quadratic programming optimizer called SNOPT. The optimization was able to constrain the noise level of the wind farms with a small impact on power output.
Curved-Folding-Inspired Deployable Compliant Rolling-Contact Element (D-Core), Todd Nelson, Robert Lang, Spencer P. Magleby, Larry L. Howell
Curved-Folding-Inspired Deployable Compliant Rolling-Contact Element (D-Core), Todd Nelson, Robert Lang, Spencer P. Magleby, Larry L. Howell
Faculty Publications
This work describes a deployable compliant rolling-contact element joint (DCORE joint) that employs curved-folding origami techniques to enable transition from a flat to deployed state. These deployable joints can be manufactured from a single sheet of material. Two fundamental configurations of the D-CORE are presented. The first configuration allows for motion similar to that of a Jacob’s ladder when the joint is in a planar state while achieving the motion of a CORE when in the deployed state. The second configuration constrains all degrees of freedom to create a static structure when the joint is in the planar state and …
High Aspect Ratio, Carbon Nanotube Membranes Decorated With Pt Nanoparticle Urchins For Micro Underwater Vehicle Propulsion Via H2O2 Decomposition, Kevin M. Marr, Bolin Chen, Eric J. Mootz, Jason Geder, Marius Pruessner, Brian J. Melde, Richard R. Vanfleet, Igor L. Medintz, Brian D. Iverson, Jonathan C. Claussen
High Aspect Ratio, Carbon Nanotube Membranes Decorated With Pt Nanoparticle Urchins For Micro Underwater Vehicle Propulsion Via H2O2 Decomposition, Kevin M. Marr, Bolin Chen, Eric J. Mootz, Jason Geder, Marius Pruessner, Brian J. Melde, Richard R. Vanfleet, Igor L. Medintz, Brian D. Iverson, Jonathan C. Claussen
Faculty Publications
The utility of unmanned Micro Underwater Vehicles (MUVs) is paramount for exploring confined spaces, but their spatial agility is often impaired when maneuvers require burst-propulsion. herein we develop high-aspect ratio (150:1), multi-walled carbon nanotube microarray membranes (CNT-MMs) for propulsive, MUV thrust generation by the decomposition of hydrogen peroxide (H2O2). The CNT-MMs are grown via chemical vapor deposition with diamond shaped pores (nominal diagonal dimensions of 4.5 × 9.0 [µm]) and subsequently decorated with urchin-like, platinum (Pt) nanoparticles via a facile, electroless, chemical deposition process. The Pt-CNT-MMs display robust, high catalytic ability with an effective activation energy …
A Study Of Carbon Infiltrated Carbon Nanotubes Fabricated On Convex Cylindrical Substrates For The Creation Of A Coronary Stent, Warren Beecroft Robison
A Study Of Carbon Infiltrated Carbon Nanotubes Fabricated On Convex Cylindrical Substrates For The Creation Of A Coronary Stent, Warren Beecroft Robison
Theses and Dissertations
This research explores the minimizing of cracks in the fabrication of carbon-infiltrated carbon nanotube (CI-CNT) forests on cylindrical rods for the purposes of creating a CI-CNT coronary stent. It is a continuation of the work begun by Jones [1] and Skousen [2] whose work included the creation of a feasible CI-CNT coronary stent on a planar surface. The current research was performed in two parts: 1) growth on the whole circumference of the rod for ~20mm in length and 2) growth in lines and patterns. Experiments were done on either a 309 or 304 stainless steel rod ~3mm in diameter.The …
Integrating Synchronous Collaborative Applications With Product Lifecycle Management Workflows, Jordan Lowell Johnson
Integrating Synchronous Collaborative Applications With Product Lifecycle Management Workflows, Jordan Lowell Johnson
Theses and Dissertations
Product Lifecycle Management (PLM) systems are used by thousands of engineering companies world wide. Improving these systems will have a drastic and global effect. One possible improvement is to integrate synchronous collaborative applications with PLM systems. These applications allow multiple people to work on a single digital object simultaneously. They have already been shown to reduce the time a task requires. Using these applications to complete a project will reduce the project time. However, simply including synchronous collaborative applications within a PLM system ignores powerful benefits that could provide further time-saving benefits. The integration must allow improved awareness at the …
Investigation Of Parameters Affecting The Nanoinjection Of Hela 229 Cancer Cells, Tyler E. Lewis
Investigation Of Parameters Affecting The Nanoinjection Of Hela 229 Cancer Cells, Tyler E. Lewis
Theses and Dissertations
The ability to deliver sequences of DNA and other molecular loads across the membrane of a cell and into its nucleus is an area of interest in the medical community. One of its many applications is that of gene therapy. In contrast to other forms of treatment, gene therapy seeks to treat diseases at the cellular level. The success of these treatments depends on the technologies for cell transfection that are available. Physical methods are sometimes able to overcome poor efficiencies of chemical methods and the safety concerns of viral methods, but are usually impractical due to the limited number …
Using The Offset Panel Technique To Develop Innovative Origami-Based Applications, Michael Robert Morgan
Using The Offset Panel Technique To Develop Innovative Origami-Based Applications, Michael Robert Morgan
Theses and Dissertations
Origami, the art of folding paper, was once only an art form. In recent years, it has collided with the world of engineering and is acting as a source of inspiration for solutions to various engineering problems. Paper, the typical material used in the art form, is thin and works well for origami, but is not often suitable for use in engineering. Researchers have developed a handful of methods for accommodating thick/rigid materials in origami design. Most of these preserve only the kinematics of the model or its range of motion. Not only does the offset panel technique (OPT) preserve …
Temperature Control In Friction Stir Welding Using Model Predictive Control, Brandon Scott Taysom
Temperature Control In Friction Stir Welding Using Model Predictive Control, Brandon Scott Taysom
Theses and Dissertations
Temperature is a very important process parameter in Friction Stir Welding (FSW), but until lately active control of temperature has not been practiced. Recently, temperature control via a PID controller has proven to be effective. Model Predictive Control (MPC) is a control method that holds promise, but has not been attempted in FSW before. Two different model forms are developed for MPC and are evaluated. The first is a simple first-order plus dead time (FOPDT) model. The second is the Hybrid Heat Source model and is more complex; it combines the heat source method and a 1D discretized thermal model …
On The Free Surface Skipping Characteristics Of Highly Deformable Elastic Spheres, Randy C. Hurd
On The Free Surface Skipping Characteristics Of Highly Deformable Elastic Spheres, Randy C. Hurd
Theses and Dissertations
When a highly deformable elastic sphere impacts a water surface at an oblique angle it can skip several times in a manner similar to a skipping stone. However, this sphere seems to skip more readily and with more ease than a traditional skipping stone. This thesis examines the improved skipping characteristics of highly deformable elastic spheres made from cured silicone rubber. The effect of impact velocity, impact angle, sphere diamter and material shear modulus on ricochet trajectory is experimentally examined using high speed photography and image processing techniques. Experimental evaluation shows that deformation is the primary contributor to an increased …