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Articles 1 - 30 of 106
Full-Text Articles in Engineering
Stochastic Simulation Of Lagrangian Particle Transport In Turbulent Flows, Guangyuan Sun
Stochastic Simulation Of Lagrangian Particle Transport In Turbulent Flows, Guangyuan Sun
Theses and Dissertations
This dissertation presents the development and validation of the One Dimensional Turbulence (ODT) multiphase model in the Lagrangian reference frame. ODT is a stochastic model that captures the full range of length and time scales and provides statistical information on fine-scale turbulent-particle mixing and transport at low computational cost. The flow evolution is governed by a deterministic solution of the viscous processes and a stochastic representation of advection through stochastic domain mapping processes. The three algorithms for Lagrangian particle transport are presented within the context of the ODT approach. The Type-I and -C models consider the particle-eddy interaction as instantaneous …
Use Of Personality Profile Assessments In The Construction Industry, Brian Richard Childs
Use Of Personality Profile Assessments In The Construction Industry, Brian Richard Childs
Theses and Dissertations
Various industries are using personality profile assessments as tools to help reduce employee turnover. Employee turnover is a continuing challenge in the construction industry that has negative effects on construction companies. Research found that it was difficult to know if companies in the construction industry are using personality profile assessments as a tool to help reduce employee turnover. After understanding that other industries were using personality profile assessments in their hiring, promoting, team building and leadership development to reduce turnover, it was desired to understand if the construction industry was doing the same. This research performed a survey among the …
Configuration Scrubbing Architectures For High-Reliability Fpga Systems, Aaron Gerald Stoddard
Configuration Scrubbing Architectures For High-Reliability Fpga Systems, Aaron Gerald Stoddard
Theses and Dissertations
Field Programmable Gate Arrays (FPGAs) are being used more frequently in space applications because of their reconfigurability and intensive processing capabilities. FPGAs in environments like space are susceptible to ionizing radiation which can cause Single Event Upsets (SEUs) in the FPGA's configuration memory. These upsets may cause the programmed user design on the FPGA to deviate from its normal behavior. Space missions cannot afford to allow important data processing applications to become corrupted due to these radiation upsets.Configuration scrubbing is an upset mitigation technique that detects and corrects upsets in an FPGA's configuration memory. Configuration scrubbing periodically monitors an FPGA's …
Characterizing The Effects Of Capillary Flow During Liquid Composite Molding, Michael Ray Morgan
Characterizing The Effects Of Capillary Flow During Liquid Composite Molding, Michael Ray Morgan
Theses and Dissertations
As the aerospace industry continues to incorporate composites into its aircraft, there will be a need for alternative solutions to the current autoclaving process. Liquid composite molding (LCM) has proven to be a promising alternative, producing parts at faster rates and reduced costs while retaining aerospace grade quality. The most important factor of LCM is controlling the resin flow throughout the fiber reinforcement during infusion, as incomplete filling of fibers is a major quality issue as it results in dry spots or voids. Void formation occurs at the resin flow front due to competition between viscous forces and capillary pressure. …
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 …
An Automated Tool For High Resolution Visualization Applied To Transient Watershed Models, Noah Robert Taylor
An Automated Tool For High Resolution Visualization Applied To Transient Watershed Models, Noah Robert Taylor
Theses and Dissertations
Numeric hydrologic models can aid in water resource management by providing predictive simulations of water behavior. As computers become more advanced, the models developed also become more complex using more data to represent larger areas for forecasting hydrologic behavior. Unfortunately, as the simulations use more data, the output often becomes difficult to manage and share without investing time and effort into setting up server environments or decreasing the quality of the output to compensate for an efficient and effective user experience. A proposed solution to facilitate the accessibility of massive hydrologic model output is through the web-based visualization tool developed …
Numerical Analysis Of Passive Force On Skewed Bridge Abutments, Zifan Guo
Numerical Analysis Of Passive Force On Skewed Bridge Abutments, Zifan Guo
Theses and Dissertations
Accounting for seismic forces and thermal expansion in bridge design requires an accurate passive force-deflection relationship for the abutment wall. Current design codes make no allowance for skew effects on passive force; however, large scale field tests indicate that there is a substantial reduction in peak passive force as skew angle increases. A reduction in passive force also reduces the transverse shear resistance on the abutment. The purpose of this study is to validate three-dimensional model using PLAXIS 3D, against large scale test results performed at Brigham Young University and to develop a set of calibrated finite element models. The …
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 …
Shaking Table Testing To Evaluate Effectiveness Of Prefabricated Vertical Drains For Liquefaction Mitigation, Caleb Robert Oakes
Shaking Table Testing To Evaluate Effectiveness Of Prefabricated Vertical Drains For Liquefaction Mitigation, Caleb Robert Oakes
Theses and Dissertations
This study was designed to evaluate the ability of vertical drains to prevent liquefaction and limit associated settlement. Drain performance was investigated using full-scale tests with vertical drains in liquefiable sand using a laminar shear box with acceleration time histories applied at the base. Performance of the sand box with drains in these tests was compared with performance of the sane box without drains in previous tests. The test data was also used to create case histories which can be used for further research and calibration of computer models. Although some investigations regarding vertical drains have been performed with centrifuge …
Galvanic Corrosion Of Magnesium Coupled To Steel At High Cathode-To-Anode Area Ratios, Dila Ram Banjade
Galvanic Corrosion Of Magnesium Coupled To Steel At High Cathode-To-Anode Area Ratios, Dila Ram Banjade
Theses and Dissertations
In this study, the impact of galvanic coupling of magnesium to steel on the corrosion rate, surface morphology, and surface film formation was investigated. In particular, the role of self-corrosion was quantified as previous studies showed discrepancies between model predictions and experimental results that were likely due to significant self-corrosion. This experimental study examined the corrosion of Mg coupled to steel in 5 wt% NaCl at cathode-to-anode area ratios that ranged from 5 to 27. Results showed that self-corrosion was significant and accounted for, on average, one-third of total corrosion. Moreover, self-corrosion varied with time and cathode size, and was …
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 …
A Pilot Study To Determine The Performance Of Tension Lap Splices In Reinforced Masonry Made With Light-Weight Grout, Brandon Richard Corbett
A Pilot Study To Determine The Performance Of Tension Lap Splices In Reinforced Masonry Made With Light-Weight Grout, Brandon Richard Corbett
Theses and Dissertations
The use of light-weight building materials in modern construction has resulted in efficient designs and considerable cost savings by reducing structural weight and supporting sections. This has only been possible because of many years of research to better understand the properties of the light-weight material, and its structural behaviors. However, light-weight grout is a relatively new building material in reinforced masonry construction and little is known about its structural properties. The main objective of this study was to determine if the use of light-weight grout would impact the performance of reinforcing steel, specifically development length, in masonry construction.The research included …
Rubidium Packaging For On-Chip Spectroscopy, Cameron Louis Hill
Rubidium Packaging For On-Chip Spectroscopy, Cameron Louis Hill
Theses and Dissertations
This thesis presents rubidium packaging methods for integration using anti-resonant reflecting optical waveguides (ARROWs) on a planar chip. The atomic vapor ARROW confines light through rubidium vapor, increases the light-vapor interaction length, decreases the size of the atomic cell to chip scales, and opens up possibilities for waveguide systems on chips for additional optoelectronic devices. Rubidium vapor packaging for long-life times are essential for realizing feasibly useful devices. Considerations of outgassing, leaking and chemical compatibilities of materials in rubidium vapor cells lead to an all-metal design. The effect of these characteristics on the rubidium D2 line spectra is considered.
Laboratory Resilient Modulus Measurements Of Aggregate Base Materials In Utah, Kirk David Jackson
Laboratory Resilient Modulus Measurements Of Aggregate Base Materials In Utah, Kirk David Jackson
Theses and Dissertations
The Utah Department of Transportation (UDOT) has fully implemented the Mechanistic-Empirical Pavement Design Guide for pavement design but has been using primarily level-three design inputs obtained from correlations to aggregate base materials developed at the national level. UDOT was interested in investigating correlations between laboratory measurements of resilient modulus, California bearing ratio (CBR), and other material properties specific to base materials commonly used in Utah; therefore, a statewide testing program was needed. The objectives of this research were to 1) determine the resilient modulus of several representative aggregate base materials in Utah and 2) investigate correlations between laboratory measurements of …
Enhanced-Resolution Processing And Applications Of The Ascat Scatterometer, Richard D. Lindsley
Enhanced-Resolution Processing And Applications Of The Ascat Scatterometer, Richard D. Lindsley
Theses and Dissertations
The ASCAT scatterometer measures the Earth surface microwave radar backscatter in order to estimate the near-surface winds over the oceans. While the spatial resolution of the conventional applications is sufficient for many purposes, other geoscience applications benefit from an improved spatial resolution. Specialized algorithms may be applied to the scatterometer data in order to reconstruct the radar backscatter on a high-resolution grid. Image reconstruction requires the spatial response function (SRF) of each measurement, which is not reported with the measurement data. To address this need, I precisely model the SRF incorporating (1) the antenna beam response, (2) the processing performed …
Evaluating Long-Term Land Cover Changes For Malheur Lake, Oregon Using Envi And Arcgis, Ryan Joseph Woods
Evaluating Long-Term Land Cover Changes For Malheur Lake, Oregon Using Envi And Arcgis, Ryan Joseph Woods
Theses and Dissertations
Land cover change over time can be a useful indicator of variations in a watershed, such as the patterns of drought in an area. I present a case study using remotely sensed images from Landsat satellites for over a 30-year period to generate classifications representing land cover categories, which I use to quantify land cover change in the watershed areas that contribute to Malheur, Mud, and Harney Lakes. I selected images, about every 4 to 6 years from late June to late July, in an attempt to capture the peak vegetation growth and to avoid cloud cover. Complete coverage of …
Integrating Process Mining With Discrete-Event Simulation Modeling, Siyao Liu
Integrating Process Mining With Discrete-Event Simulation Modeling, Siyao Liu
Theses and Dissertations
Discrete-event simulation (DES) is an invaluable tool which organizations can use to help better understand, diagnose, and optimize their operational processes. Studies have shown that for the typical DES exercise, the greatest amount of time is spent on developing an accurate model of the process that is to be studied. Process mining, a similar field of study, focuses on using historical data stored in software databases to accurate recreate and analyze business processes. Utilizing process mining techniques to help rapidly develop DES models can drastically reduce the amount of time spent building simulation models, which ultimately will enable organizations to …
A Compact Phased Array Radar For Uas Sense And Avoid, Jonathan Cullinan Spencer
A Compact Phased Array Radar For Uas Sense And Avoid, Jonathan Cullinan Spencer
Theses and Dissertations
As small unmanned aerial systems (UAS) are introduced into the national airspace, measures must be introduced to ensure that they do not interfere with manned aviation and other UAS. Radar provides an attractive solution because of its inherent range accuracy and because it works in diverse weather and lighting conditions. Traditional radar systems, however, are large and high power and do not meet the size, weight and power (SWaP) constraints imposed by UAS, and fully integrated automotive solution do not provide the necessary range. This thesis proposes a compact radar system that meets both the SWaP and range requirements for …
Deriving System Vulnerabilities Using Log Analytics, Matthew Somers Higbee
Deriving System Vulnerabilities Using Log Analytics, Matthew Somers Higbee
Theses and Dissertations
System Administrators use many of the same tactics that are implemented by hackers to validate the security of their systems, such as port scanning and vulnerability scanning. Port scanning is slow, and can be highly inaccurate. After a scan is complete, the results of the scan must be cross checked with a vulnerability database to discover if any vulnerabilities are present. While these techniques are useful, they have severe limitations. System Administrators have full access to all of their machines. They should not have to rely exclusively on port scanning them from the outside of their machines to check for …
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 …
High-Efficiency Passive And Active Phased Arrays And Array Feeds For Satellite Communications, Zhenchao Yang
High-Efficiency Passive And Active Phased Arrays And Array Feeds For Satellite Communications, Zhenchao Yang
Theses and Dissertations
Satellite communication (Satcom) services are used worldwide for voice, data, and video links due to various appealing features. Parabolic reflector antennas are typically used to serve a cost effective scheme for commercial applications. However, mount degradation, roof sag, and orbital decay motivate the need for beam steering. Limited scan range beam steering opens a third option for electronic beam steering with lower cost than full aperture phased arrays and higher tracking speed and accuracy than mechanical-only steering.Multiple high efficiency passive patch array feeds were designed, fabricated, and measured, including a 2x2 MSA array, a stacked shorted annular patch antenna, and …
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 …
An Improved Dynamic Particle Packing Model For Prediction Of The Microstructure In Porous Electrodes, Chien-Wei Chao
An Improved Dynamic Particle Packing Model For Prediction Of The Microstructure In Porous Electrodes, Chien-Wei Chao
Theses and Dissertations
The goal of this work is to develop a model to predict the microstructure of Li-ion batteries, specifically focusing on the cathode component of the batteries. This kind of model has the potential to assist researchers and battery manufacturers who are trying to optimize the capacity, cycle life, and safety of batteries. Two dynamic particle packing (DPP) microstructure models were developed in this work. The first is the DPP1 model, which simulates the final or dried electrode structure by moving spherical particles under periodic boundaries using Newton's laws of motion. The experience derived from developing DPP1 model was beneficial in …
Calibration And Validation Of The Rapidscat Scatterometer Using Natural Land Targets, Nathan Mark Madsen
Calibration And Validation Of The Rapidscat Scatterometer Using Natural Land Targets, Nathan Mark Madsen
Theses and Dissertations
RapidScat is a Ku-band scatterometer that was launched September 2014 and is currently operating on the International Space Station. It estimates ocean vector winds through accurate measurement of the normalized radar coefficient (σ0) of the ocean surface. In order to ensure the accuracy of σ0 measurements and consistency with previous Ku-band scatterometers, post-launch calibration and validation is necessary. Calibration and validation is performed using natural land targets, namely the Amazon and Congo rainforests, to complement calibration efforts over the ocean. The σ0 response of the targets is estimated with respect to viewing angle and time of …
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 …
Bending Behavior Of Carbon/Epoxy Composite Isobeam Structures, Brandon A. Asay
Bending Behavior Of Carbon/Epoxy Composite Isobeam Structures, Brandon A. Asay
Theses and Dissertations
This research demonstrated the fabrication, flexural testing, and analysis of nominally 5 ft (1.5 m) 6-bay and 10 ft (3 m) 12-bay carbon/epoxy IsoBeam™ structures. The rectangular cross-section was 5 in (12.7 cm) wide by 10 in (25.4 cm) high. The IsoBeam structure is a composite lattice structure that is a geometric derivative of the IsoTruss® structure. Modifying the geometry to yield a rectangular cross-section provides additional applications for these beams as structural elements in buildings, aircraft, vehicles, and other structures. The diameters of the constituent members of the IsoBeam, namely the longitudinal and diagonal members, were sized such that …
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 …