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Articles 1 - 30 of 97
Full-Text Articles in Engineering
Efficient Rotation Algorithms For Texture Evolution, Mark W. Esty
Efficient Rotation Algorithms For Texture Evolution, Mark W. Esty
Theses and Dissertations
Texture evolution is a vital component of many computational tools that link structure, properties and processes of polycrystalline materials. By definition, this evolution process involves the manipulation, via rotation, of points in orientation space. The computational requirements of the current methods being used to rotate crystalline orientations are a significant limiting factor in the drive to merge the texture information of materials into the engineering design process. The goal of this research is to find and implement a practical rotation algorithm that can significantly decrease the computation time required to rotate macroscopic and microscopic crystallographic textures. Three possible algorithms are …
Development Of A Methodology For Numerical Simulation Of A D C Arc Discharge In A Liquid Dielectric, Christopher James Lewis
Development Of A Methodology For Numerical Simulation Of A D C Arc Discharge In A Liquid Dielectric, Christopher James Lewis
Theses and Dissertations
The majority of literature regarding the numerical simulation of arc discharges in gaseous environments has used a plasma physics approach. Virtually all simulations treat the discharge as an idealized gaseous plasma, which can be described by temperature, pressure, and electric field. This approach can work well if the media is a shielding gas such as Argon; however, the approach does not work well for processes such as underwater welding, EDM, and underwater discharges used to generate high purity particles. The reason these discharges do not have many extensive simulation efforts as described in the literature is because they occur in …
Passive Earth Pressures On A Pile Cap With A Dense Sand Backfill, Robert Ashall Marsh
Passive Earth Pressures On A Pile Cap With A Dense Sand Backfill, Robert Ashall Marsh
Theses and Dissertations
Pile groups are often used to provide support for structures. Capping a pile group further adds to the system's resistance due to the passive earth pressure from surrounding backfill. While ultimate passive earth pressure under static loading conditions can be readily calculated using several different theories, the effects of cyclic and dynamic loading on the passive earth pressure response are less understood. Data derived from the full-scale testing of a pile cap system with a densely compacted sand backfill under static, cyclic, and dynamic loadings was analyzed with particular focus on soil pressures measured directly using pressure plates. Based on …
Energy Dissipation Caused By Asphalt Roadway Gouges For Use In Accident Reconstruction, Charles L. Crosby
Energy Dissipation Caused By Asphalt Roadway Gouges For Use In Accident Reconstruction, Charles L. Crosby
Theses and Dissertations
In reconstruction of on-roadway vehicle accidents, roadway surface gouges and the forces and energy attributed to the related vehicle components become important keys to resolving an accurate accident reconstruction. These roadway gouge forces vary depending upon such factors as surface temperature and the velocity and geometry of the gouging mechanism. Accounting for the forces applied to vehicle components and the energy dissipated from such forces can be helpful in accident reconstruction where supporting data exists. This research documents the force necessary to create a given roadway gouge geometry. Controlled pavement gouging tests were performed using roadway surface temperature and gouging …
Studies On The Performance And Impact Of Channel Estimation In Mimo And Ofdm Systems, Michael David Larsen
Studies On The Performance And Impact Of Channel Estimation In Mimo And Ofdm Systems, Michael David Larsen
Theses and Dissertations
The need for reliable, high-throughput, mobile wireless communication technologies has never been greater as increases in the demand for on-the-go access to information, entertainment, and other electronic services continues. Two such technologies, which are at the forefront of current research efforts, are orthogonal frequency division multiplexing (OFDM) and multiple-input multiple-output (MIMO) systems, their union being known simply as MIMO-OFDM. The successful performance of these technologies depends upon the availability of accurate information concerning the wireless communication channel. In this dissertation, several issues related to quality of this channel state information (CSI) are studied. Specifically, the first part of this dissertation …
The Effect Of Flowable Fill On The Lateral Resistance Of Driven-Pile Foundations, Dustin David Miner
The Effect Of Flowable Fill On The Lateral Resistance Of Driven-Pile Foundations, Dustin David Miner
Theses and Dissertations
Flowable fill was used to strengthen the soft soil surrounding piles and behind the pile cap. The flowable fill placed beneath the pile cap surrounding the piles showed no appreciable increase in lateral resistance, this was partially due to the fact that the flowable fill placed had an unconfined compressive strength of 30 psi. Flowable fill was also used to replace a 12 ft wide, 6 ft thick, and 6 ft deep zone consisting of an average 475 psf clay that was adjacent to a 9-pile group in 3x3 pile configuration capped with a 9 ft x 9 ft x …
Prediction Of Fluid Viscosity Through Transient Molecular Dynamic Simulations, Jason Christopher Thomas
Prediction Of Fluid Viscosity Through Transient Molecular Dynamic Simulations, Jason Christopher Thomas
Theses and Dissertations
A novel method of calculating viscosity from molecular dynamics simulations is developed, benchmarked, and tested. The technique is a transient method which has the potential to reduce CPU requirements for many conditions. An initial sinusoidal velocity profile is overlaid upon the peculiar velocities of the individual molecules in an equilibrated simulation. The transient relaxation of this initial velocity profile is then compared to the corresponding analytical solution of the momentum equation by adjusting the viscosity-related parameters in the constitutive equation that relate the shear rate to the stress tensor. The newly developed Transient Molecular Dynamics (TMD) method was tested for …
Compact Trench-Based Silicon-On-Insulator Rib Waveguide Ring Resonator With Large Free Spectral Range, Seunghyun Kim, Gregory P. Nordin, Weisheng Hu, Yusheng Qian, Jiguo Song, Gregory L. Wojcik
Compact Trench-Based Silicon-On-Insulator Rib Waveguide Ring Resonator With Large Free Spectral Range, Seunghyun Kim, Gregory P. Nordin, Weisheng Hu, Yusheng Qian, Jiguo Song, Gregory L. Wojcik
Faculty Publications
We demonstrate a compact trench-based silicon-on-insulator (SOI) rib waveguide ring resonator comprised of trench-based bends and splitters. It has a perimeter of 50 μm and occupies an area of only 25×25 μm. The measured free spectral range (FSR) is 13.2 nm, which the largest reported for an SOI rib waveguide ring resonator. The measured FSR, full width at half maximum, and quality factor match reasonably well with analytical calculations. Further calculation shows that a FSR of 50.8 nm is achievable for an SOI rib waveguide ring resonator with a perimeter of 15 μm.
Energy Efficiency Of Hydrogen Sulfide Decomposition In A Pulsed Corona Discharge Reactor, Morris D. Argyle, Sanil John, Jerry C. Hamann, Suresh S. Muknahallipatna, Stanislaw Legowski, John F. Ackerman
Energy Efficiency Of Hydrogen Sulfide Decomposition In A Pulsed Corona Discharge Reactor, Morris D. Argyle, Sanil John, Jerry C. Hamann, Suresh S. Muknahallipatna, Stanislaw Legowski, John F. Ackerman
Faculty Publications
A novel pulsed corona wire-in-tube reactor with quartz view-ports allowed visual observation of the effect of charge voltage and gas composition on the corona distribution. The H2S conversion and energy efficiency of H2S decomposition in this pulsed corona discharge reactor varied at constant power due to the selected values of the electrical parameters of pulse forming capacitance, charge voltage, and pulse frequency. Low pulse forming capacitance, low charge voltage, and high pulse frequency operation produce the highest energy efficiency of H2S conversion at constant power. H2S conversion is more efficient in Ar-N2 gas mixtures than in Ar or N2. these …
A Study Of Electricians' Preferences Of Pvc And Alternative Conduit Materials In The State Of Utah, Robert Andrus
A Study Of Electricians' Preferences Of Pvc And Alternative Conduit Materials In The State Of Utah, Robert Andrus
Theses and Dissertations
Polyvinyl Chloride, commonly known as PVC is a common and effective construction material. PVC is also one of the most common types of plastic. In 2008, global production and consumption of PVC was approximately 34.5 million tons. The construction industry is responsible for about 70% of the world's consumption of PVC. The largest construction use of PVC is for pipe and conduit. Modern construction, especially structures built for data services depend heavily upon PVC conduit for underground pathways to distribute electricity and data. PVC is also at the center of a fierce effort by environmental groups who would like to …
Studies Of Coal Nitrogen Release Chemistry For Oxyfuel Combustion And Chemical Additives, John M. Sowa
Studies Of Coal Nitrogen Release Chemistry For Oxyfuel Combustion And Chemical Additives, John M. Sowa
Theses and Dissertations
Pollution is one of the greatest concerns with pulverized coal combustion. With tightening standards on pollution emissions, more information is needed to create better design models. Burner modifications are the most efficient changes that can be made to assure sufficient carbon burnout and low NOx emissions. Experiments were performed in the BYU Flat Flame Burner (FFB) lab, operating under fuel rich conditions for pyrolysis experiments and fuel lean conditions for char oxidation experiments. Effects of temperature, coal rank, residence time, and post flame oxygen content on mass release, nitrogen release, and reactivity were examined. Elemental and Inductively coupled plasma (ICP) …
Performance Of A Full-Scale Lateral Foundation With Fine And Coarse Gravel Backfills Subjected To Static, Cyclic, And Dynamic Lateral Loads, Joshua M. Pruett
Performance Of A Full-Scale Lateral Foundation With Fine And Coarse Gravel Backfills Subjected To Static, Cyclic, And Dynamic Lateral Loads, Joshua M. Pruett
Theses and Dissertations
Full-scale lateral load tests were performed on a pile cap with five backfill conditions: no backfill, densely compacted fine gravel, loosely compacted fine gravel, densely compacted coarse gravel, and loosely compacted coarse gravel. Static loads, applied by hydraulic load actuators, were followed by low-frequency, actuator-driven cyclic loads as well as higher frequency dynamic loads from an eccentric mass shaker. Passive resistance from the backfill significantly increased the lateral capacity of the pile cap. Densely compacted backfill materials contributed about 70% of the total system resistance, whereas loosely compacted backfill materials contributed about 40%. The mobilized passive resistance occurred at displacement-to-height …
Impact Of Large Gravity Loads On Buckling Restrained Braced Frame Performance, Mark Thurgood Matthews
Impact Of Large Gravity Loads On Buckling Restrained Braced Frame Performance, Mark Thurgood Matthews
Theses and Dissertations
The Buckling Restrained Braced Frame (BRBF) is used in steel structures as a lateral load resisting system for seismic events. In typical design procedure the impact of gravity loads acting on BRBFs is neglected and the beams and columns of the structure are designed to resist all gravity loads. In actuality BRBFs are supporting portions of gravity loads acting on the structure which may be changing the overall performance of BRBFs. The purpose of this study is to determine the impact of large gravity loads on BRBF performance. This is done using finite element analysis to test two different structures …
An Improved Cube Cell Assembly For The Use With High Pressure/High Temperature Cubic Apparatus In Manufacturing Polycrystalline Diamond Compact Inserts, Kevin Christian Bach
An Improved Cube Cell Assembly For The Use With High Pressure/High Temperature Cubic Apparatus In Manufacturing Polycrystalline Diamond Compact Inserts, Kevin Christian Bach
Theses and Dissertations
The goal for this research was to reduce the current manufacturing cost of the polycrystalline diamond compact (PDC) inserts utilized in the natural gas and oil drilling industry while not reducing their current performance. Polycrystalline Diamond is added to the tungsten-carbide (WC) substrates commonly utilized in these applications because of its greater wear and thermal resistance. With the current cube cell design for the high-pressure/high-temperature apparatus, it is necessary to bond an extra WC substrate to the polycrystalline diamond insert to achieve the sizes generally ordered by the customers. The problem of bonding the extra WC substrate was solved by …
Vision-Based Precision Landings Of A Tailsitter Uav, Paul Travis Millet
Vision-Based Precision Landings Of A Tailsitter Uav, Paul Travis Millet
Theses and Dissertations
We present a method of performing precision landings of a vertical take-off and landing (VTOL) unmanned air vehicle (UAV) with the use of an onboard vision sensor and information about the aircraft's orientation and altitude above ground level (AGL). A method for calculating the 3-dimensional location of the UAV relative to a ground target of interest is presented as well as a navigational controller to position the UAV above the target. A method is also presented to prevent the UAV from moving in a way that will cause the ground target of interest to go out of view of the …
Improved Implementation Of Kirkwood-Buff Solution Theory In Periodic Molecular Simulations, Joseph W. Nichols, Stan G. Moore, Dean R. Wheeler
Improved Implementation Of Kirkwood-Buff Solution Theory In Periodic Molecular Simulations, Joseph W. Nichols, Stan G. Moore, Dean R. Wheeler
Faculty Publications
Kirkwood-Buff (KB) solution theory is a means to obtain certain thermodynamic derivatives from knowledge of molecular distributions. In actual practice the required integrals over radial distribution functions suffer inaccuracies due to finite-distance truncation effects and their use in closed systems. In this work we discuss how best to minimize these inaccuracies under traditional KB theory. In addition we implement a method for calculating KB quantities in molecular simulations with periodic boundary conditions and particularly within the canonical ensemble. The method is based on a finite-Fourier-series expansion of molecular concentration fluctuations and leads to more reliable results for a given computational …
In-Plane, All-Photonic Transduction Method For Silicon Photonic Microcantilever Array Sensors, Jong Wook Noh
In-Plane, All-Photonic Transduction Method For Silicon Photonic Microcantilever Array Sensors, Jong Wook Noh
Theses and Dissertations
We have invented an in-plane all-photonic transduction method for photonic microcantilever arrays that is scalable to large arrays for sensing applications in both bio- and nanotechnology. Our photonic transduction method utilizes a microcantilever forming a single mode rib waveguide and a differential splitter consisting of an asymmetric multimode waveguide and a Y-branch waveguide splitter. The differential splitter's outputs are used to form a differential signal that has a monotonic response to microcantilever deflection. A differential splitter using an amorphous silicon strip-loaded multimode rib waveguide is designed and fabricated to demonstrate the feasibility of the in-plane photonic transduction method. Our initial …
Variability In Construction Of Cement-Treated Base Layers: Probabilistic Analysis Of Pavement Life Using Mechanistic-Empirical Approach, Tyler J. Rogers
Variability In Construction Of Cement-Treated Base Layers: Probabilistic Analysis Of Pavement Life Using Mechanistic-Empirical Approach, Tyler J. Rogers
Theses and Dissertations
The primary objective of this research was to quantify the improvement in service life of a flexible pavement constructed using full-depth reclamation (FDR) in conjunction with cement stabilization when specified reductions in the spatial variability of specific construction-related parameters are achieved. This study analyzed pavement data obtained through field and laboratory testing of a reconstruction project in northern Utah. Data analyses included multivariate regression, Monte Carlo simulation, and mechanistic-empirical analyses of a model pavement structure. The results of the research show a steadily increasing trend in 28-day unconfined compressive strength of the cement-treated base (CTB) layer with increasing reductions in …
Automated Calibration Of The Gssha Watershed Model: A Look At Accuracy And Viability For Routine Hydrologic Modeling, Kayson M. Shurtz
Automated Calibration Of The Gssha Watershed Model: A Look At Accuracy And Viability For Routine Hydrologic Modeling, Kayson M. Shurtz
Theses and Dissertations
The goal of hydrologic models is to accurately predict a future event of a given magnitude. Historic data are often used to calibrate models to increase their ability to forecast accurately. The GSSHA model is a distributed model that uses physical parameters and physics based computations to compute water flow from cell to cell based on a 2 dimensional grid. The goal of calibration is to obtain good estimates for the actual parameters of the watershed. These parameters should then transfer to other storm events of different magnitudes more easily than an empirical model. In conducting this research three watersheds …
An Evaluation Of Quikscat Uhr Wind Product's Effectiveness In Determining Selected Tropical Cyclone Characteristics, Faozi Said
Theses and Dissertations
While the standard wind product (L2B) available operationally in near-real time from SeaWinds on QuikSCAT is only 25 km in resolution, QuikSCAT data can be enhanced to yield a 2.5 km ultra-high resolution (UHR) product. The latter can be used to help estimate Tropical Cyclone (TC) characteristics such as TC eye center and wind radii. Two studies are conducted in this thesis, in which QuikSCAT UHR wind product's effectiveness in estimating these TC characteristics is evaluated. First, a comparison is made between the analyst's choice of eye location based on UHR images and interpolated best-track position. In this analysis, the …
Slab-Coupled Optical Fiber Sensors For Electric Field Sensing Applications, Richard S. Gibson
Slab-Coupled Optical Fiber Sensors For Electric Field Sensing Applications, Richard S. Gibson
Theses and Dissertations
This dissertation presents the creation of slab coupled optical sensors (SCOS) for electric field sensing applications. SCOS devices utilize the benefits of an optical fiber system for high bandwidth and low electromagnetic interference. These sensors are fabricated by means of mode coupling between a small section of D-shaped optical fiber (D-fiber) with a multi-mode electro-optic slab waveguide. Electric field detection is accomplished by monitoring the behavior of the resonances, seen as transmission dips in the D-fiber transmission, as they shift with electric fields. The novelties of SCOS devices include their small compact nature, potential for sensor multiplexing and a dielectric …
Improving Accuracy In Microwave Radiometry Via Probability And Inverse Problem Theory, Derek Lavell Hudson
Improving Accuracy In Microwave Radiometry Via Probability And Inverse Problem Theory, Derek Lavell Hudson
Theses and Dissertations
Three problems at the forefront of microwave radiometry are solved using probability theory and inverse problem formulations which are heavily based in probability theory. Probability theory is able to capture information about random phenomena, while inverse problem theory processes that information. The use of these theories results in more accurate estimates and assessments of estimate error than is possible with previous, non-probabilistic approaches. The benefits of probabilistic approaches are expounded and demonstrated. The first problem to be solved is a derivation of the error that remains after using a method which corrects radiometric measurements for polarization rotation. Yueh [1] proposed …
Investigate Correlations Of Microstructures, Mechanical Properties And Fsw Process Variables In Friction Stir Welded High Strength Low Alloy 65 Steel, Lingyun Wei
Theses and Dissertations
The present study focuses on developing a relationship between process variables, mechanical properties and post weld microstructure in Friction Stir Welded HSLA 65 steel. Fully consolidated welds can be produced in HSLA 65 steel by PCBN Convex-Scrolled-Shoulder-Step-Spiral (CS4) tool over a wide range of parameters. Microstructures in the nugget center (NC) are dominated by lath bainite and a few polygonal/allotriomorphic grain boundary ferrites. FSW dependent variables are related to FSW independent variables by non-linear relationship. Heat input is identified to be the best parameter index to correlate with microstructures. With increasing heat input, the volume of bainite is reduced, the …
Optimizing The Release And Methylation Of Bacterial Endospore Dipicolinic Acid, Aaron N. Nackos
Optimizing The Release And Methylation Of Bacterial Endospore Dipicolinic Acid, Aaron N. Nackos
Theses and Dissertations
Rapid, portable detection of biological threat agents such as Bacillus anthracis endospores (“spores”) is extremely important given the real and perceived threats of bioterrorism. Gas chromatography-mass spectrometry (GC-MS) is an excellent general means for chemical detection, although special sample preparation and specialized equipment are required to employ GC-MS for detecting biological agents such as spores in the field. A GC sample introduction probe consisting of a helical wire that can be retracted inside a syringe needle, called a coiled wire filament (CWF), was employed as a simple, passively-heated means to introduce the mixture of spores plus reagents for thermochemolysis methylation …
In-Plane All-Photonic Transduction With Differential Splitter Using Double-Step Rib Waveguide For Photonic Microcantilever Arrays, Ryan Anderson, Seunghyun Kim, Gregory P. Nordin, Jong Wook Noh, Weisheng Hu
In-Plane All-Photonic Transduction With Differential Splitter Using Double-Step Rib Waveguide For Photonic Microcantilever Arrays, Ryan Anderson, Seunghyun Kim, Gregory P. Nordin, Jong Wook Noh, Weisheng Hu
Faculty Publications
We report a differential splitter consisting of an asymmetric double-step multimode rib waveguide and a Y-branch splitter for in-plane photonic transduction of photonic microcantilever deflection. Arrays of photonic microcantilevers are integrated with differential splitters and an optical waveguide network to demonstrate uniformity and sensitivity of transduction. Measurement results from multiple arrays indicate a sensitivity of 0.32 x 10-3 nm-1 and minimum detectable deflection of 141 pm for a 3.5 Hz measurement bandwidth.
Research In Information Technology: Analysis Of Existing Graduate Research, Christopher John Cole
Research In Information Technology: Analysis Of Existing Graduate Research, Christopher John Cole
Theses and Dissertations
Information Technology is an academic discipline that is well recognized by the academic community. There is an increasing number of schools offering degrees in Information Technology and has there is an official curriculum published with the ACM/IEEE computing Curriculum. A concern with Information Technology as an academic discipline is that it does not have a clearly defined set of research issues which are not studied by any other discipline. One way to propose this set of issues is to perform a “bottom-up” analysis and gather research in IT that has already been published. This research can then be analyzed for …
Automated Data Import And Revision Management In A Product Lifecycle Management Environment, Brad Walton Brooks
Automated Data Import And Revision Management In A Product Lifecycle Management Environment, Brad Walton Brooks
Theses and Dissertations
A method has been created that addresses the issues that prohibit the conversion of product artifacts into a secure, efficient and reliable Product Lifecycle Management (PLM) environment. These issues include automatic import of data into a PLM system and revision control of such data. A test case is shown which specifically addresses these issues as they pertain to the management of both legacy and new engineering data in a PLM system.
Low Cost/ High Precision Flight Dynamics Estimation Using The Square-Root Unscented Kalman Filter, Trevor H. Paulsen
Low Cost/ High Precision Flight Dynamics Estimation Using The Square-Root Unscented Kalman Filter, Trevor H. Paulsen
Theses and Dissertations
For over a decade, Brigham Young University's Microwave Earth Remote Sensing (MERS) team has been developing SAR systems and SAR processing algorithms. In order to create the most accurate image reconstruction algorithms, detailed aircraft motion data is essential. In 2008, the MERS team purchased a costly inertial measurement unit (IMU) coupled with a high precision global positioning system (GPS) from NovAtel, Inc. In order to lower the cost of obtaining detailed motion measurements, the MERS group decided to build a system that mimics the capability the NovAtel system as closely as possible for a much lower cost. As a first …
Haptic Collision Avoidance For A Remotely Operated Quadrotor Uav In Indoor Environments, Adam M. Brandt
Haptic Collision Avoidance For A Remotely Operated Quadrotor Uav In Indoor Environments, Adam M. Brandt
Theses and Dissertations
A quadrotor is an omnidirectional unmanned air vehicle that is suitable for indoor flight because of its ability to hover and maneuver in confined spaces. The remote operation of this type of vehicle is difficult due to a lack of sensory perception; typically, the view from the onboard camera is the only information transmitted to the pilot. This thesis proposes using force feedback exerted by the command input device on the hand of the pilot to assist in avoiding collisions while navigating in indoor environments. Five candidate algorithms are presented for calculating the forces to be felt by the pilot …
New Low-Complexity Equalizers For Offset Qpsk, Qiang Lei, Michael D. Rice
New Low-Complexity Equalizers For Offset Qpsk, Qiang Lei, Michael D. Rice
Faculty Publications
Reduced-complexity linear and decision-feedback equalizers for use with offset QPSK are described and analyzed. The analysis and simulations show that reduced-complexity equalizers have 1/4 the complexity and achieve this at a loss that depends on the channel. As an example, the loss for the “Proakis B” channel is 2.7 dB for the linear equalizer and 0.8 dB for the decision feedback equalizer.