Engineering Commons^™

Automated Delay Estimation At Signalized Intersections: Phase I Concept And Algorithm Development, Taylor R. Forbush

Theses and Dissertations

Currently there are several methods to measure the performance of surface streets, but their capabilities in dynamically estimating vehicle delay are limited. The objective of this research is to develop a method to automate traffic delay estimation in real-time using existing field traffic data collection technologies. This research has focused on method and algorithm development that can be applied to existing technologies. Two algorithms were developed to run automatically using Microsoft Excel and Visual Basic to calculate traffic delay from data collected from existing vehicle detection. The algorithms were developed using computer modeling software to simulate different lane configurations. The …

Culvert Roughness Elements For Native Utah Fish Passage: Phase I, Lindsay D. Esplin

Theses and Dissertations

Culverts can increase stream velocities as a result of reduced waterway areas and prevent upstream passage of small non-salmonid fish such as the Native Utah Leatherside chub (Gila copei) and Longnose dace (Rhinichthyscataractae). To mitigate this problem, current culvert design standards for fish passage match sustained fish swim speeds with average cross sectional velocity through the culvert. Such policies dictate relatively large barrels and do not recognize the role of reduced velocity zones near culvert boundaries. Obstacles and streambed substrate create turbulent regions with lower velocity zones that can increase upstream fish passage. A comparison of …

A High-Gain, Low-Power Cmos Operational Amplifier Using Composite Cascode Stage In The Subthreshold Region, Rishi Pratap Singh

Theses and Dissertations

This thesis demonstrates that the composite cascode differential stage, operating in the subthreshold region, can form the basis of a high gain (113 dB) and low-power op amp (28.1 µW). The circuit can be fabricated without adding a compensation capacitance. The advantages of this architecture include high voltage gain, low bandwidth, low harmonic distortion, low quiescent current and power, and small chip area. These advantages suggest that this design might be well-suited for biomedical applications where low power, low noise bio-signal amplifiers capable of amplifying signals in the millihertz-to-kilohertz range is required.

System Identification, State Estimation, And Control Of Unmanned Aerial Robots, Caleb H. Chamberlain

Theses and Dissertations

This thesis describes work in a variety of topics related to aerial robotics, including system identification, state estimation, control, and path planning. The path planners described in this thesis are used to guide a fixed-wing UAV along paths that optimize the aircraft's ability to track a ground target. Existing path planners in the literature either ignore occlusions entirely, or they have limited capability to handle different types of paths. The planners described in this thesis are novel in that they specifically account for the effect of occlusions in urban environments, and they can produce a much richer set of paths …

Sawdust Pyrolysis And Petroleum Coke Co2 Gasification At High Heating Rates, Aaron D. Lewis

Theses and Dissertations

Clean and efficient electricity can be generated using an Integrated Gasification Combined Cycle (IGCC). Although IGCC is typically used with coal, it can also be used to gasify other carbonaceous species like biomass and petroleum coke. It is important to understand the pyrolysis and gasification of these species in order to design commercial gasifiers and also to determine optimal conditions for operation. High heating-rate (100,000 K/s) pyrolysis experiments were performed with biomass (sawdust) in BYU's atmospheric flat-flame burner reactor at conditions ranging from 1163 to 1433 K with particle residence times ranging from 23 to 102 ms. Volatile yields and …

Evaluation Of The Effectiveness Of A Variable Advisory Speed System On Queue Mitigation In Work Zones, Aaron B. Wilson

Theses and Dissertations

Construction is increasing due to increased demand and degradation of existing infrastructure. This construction often results in a reduced number of traffic lanes or lane width during construction, which often creates queue at the entrance to work zones. Variable Advisory Speed Systems (VASS) provide drivers with advanced warning regarding traffic speeds downstream to help them make better decisions in advance of problems that may exist downstream. The purpose of this study was to evaluate the effectiveness of a VASS at mitigating queues in work zone entrances during peak hour conditions. It was anticipated that by implementing a VASS queues would …

Tool Life Of Various Tool Materials When Friction Spot Welding Dp980 Steel, Christopher Shane Ridges

Theses and Dissertations

In this study, friction spot welding was used to join DP980 steel sheet. Four different ultra-hard tool materials were used with the objective of determining which tool material produced the highest number of acceptable-strength welds. Three of the tools were composed of various mixtures of polycrystalline cubic Boron Nitride (PCBN), Tungsten, and Rhenium. These materials are referred to herein as Q60, Q70, and Q80, the "Qxx" designation denoting the percentage of the volume of the tool material composed of PCBN. The fourth tool tested was composed entirely of PCBN. The Q70 tool produced approximately 1100 welds of acceptable strength before …

Effects Of Damköhler Number On Flame Extinction And Reignition In Turbulent Non-Premixed Flames Using Dns, David O. Lignell, Jacqueline H. Chen, Hans A. Schmutz

Faculty Publications

Results from a parametric study of flame extinction and reignition with varying Damköhler number using direct numerical simulation are presented. Three planar, non-premixed ethylene jet flames were simulated at a constant Reynolds number of 5120. The fuel and oxidizer stream compositions were varied to adjust the steady laminar extinction scalar dissipation rate, while maintaining constant flow and geometric conditions. Peak flame extinction varies from approximately 40% to nearly global blowout as the Damköhler number decreases. The degree of extinction significantly affects the development of the jets and the degree of mixing of fuel, oxidizer, and combustion products prior to reignition. …

Xdl-Based Hard Macro Generator, Subhrashankha Ghosh

Theses and Dissertations

In a conventional hardware design flow, the compilation process to create the physical circuit on the FPGA takes a long time. HMFlow is a design flow that reduces the compilation time by using pre-compiled modules called hard macros. HMFlow uses System Generator to create the designs, which are then converted to hard macros. The hard macro creation process takes a long time and a possible solution is a hard macro generator called XdlCoreGen, which is described in this thesis. XdlCoreGen can quickly create fully mapped and placed hard macros using XDL. XDL is a human readable design format that describes …

Cobalt Fischer-Tropsch Catalyst Preparation: Overview Of Preparation Techniques On Alumina Pellets, Brad M. Hancock, Kari M. Cook, William C. Hecker

Student Works

Fischer-Tropsch (FT) synthesis is a reaction used to convert carbon monoxide and hydrogen into high-quality liquid fuels. The FT process has been considered a promising alternative route for producing diesel fuel to meet an increasing demand for oil around the world and more strict limits to regulate auto tailpipe emissions. The U.S. Environmental Protection Agency has demanded a reduction in diesel fuel sulfur content to 15 ppm. While crude oil contains finite amounts of sulfur that needs further removal or treatment before it could be used as a commercial fuel, FT synthesis produces sulfur-free diesel fuel. The reaction takes place …

Thermodynamic, Sulfide, Redox Potential, And Ph Effects On Syngas Fermentation, Peng Hu

Theses and Dissertations

Recently, work in ethanol production is exploring the fermentation of syngas (primarily CO, CO2, and H2) following gasification of cellulosic biomass. The syngas fermentation by clostridium microbes utilizes the Wood-Ljungdahl metabolic pathway. Along this pathway, the intermediate Acetyl-CoA typically diverges to produce ethanol, acetic acid, and/or cell mass. To develop strategies for process optimization, a thermodynamic analysis was conducted that provided a detailed understanding of the favorability of the reactions along the metabolic pathway. Thermodynamic analysis provided identification of potentially limiting steps. Once these limiting reactions were identified, further thermodynamic analysis provided additional insights into the ways in which reaction …

Analysis And Mitigation Of Seu-Induced Noise In Fpga-Based Dsp Systems, Brian Hogan Pratt

Theses and Dissertations

This dissertation studies the effects of radiation-induced single-event upsets (SEUs) on digital signal processing (DSP) systems designed for field-programmable gate arrays (FPGAs). It presents a novel method for evaluating the effects of radiation on DSP and digital communication systems. By using an application-specific measurement of performance in the presence of SEUs, this dissertation demonstrates that only 5-15% of SEUs affecting a communications receiver (i.e. 5-15% of sensitive SEUs) cause critical performance loss. It also reports that the most critical SEUs are those that affect the clock, global reset, and most significant bits (MSBs) of computation. This dissertation also demonstrates …

On-Orbit Fpga Seu Mitigation And Measurement Experiments On The Cibola Flight Experiment Satellite, William A. Howes

Theses and Dissertations

This work presents on-orbit experiments conducted to validate SEU mitigation and detection techniques on FPGA devices and to measure SEU rates in FPGAs and SDRAM. These experiments were designed for the Cibola Flight Experiment Satellite (CFESat), which is an operational technology pathfinder satellite built around 9 Xilinx Virtex FPGAs and developed at Los Alamos National Laboratory. The on-orbit validation experiments described in this work have operated for over four thousand FPGA device days and have validated a variety of SEU mitigation and detection techniques including triple modular redundancy, duplication with compare, reduced precision redundancy, and SDRAM and FPGA block memory …

A 3-D Chain Algorithm With Pseudo-Rigid-Body Model Elements, Robert Parley Chase, Robert H. Todd, Larry L. Howell, Spencer P. Magleby

Faculty Publications

A chain algorithm element is created from pseudo-rigid-body segments and used in a chain calculation that accurately predicts the force deflection relationship of beams with large 3-D deflections. Each chain element is made up of three pseudo-rigid-body models superimposed on each other acting orthogonally in relation to each other. The chain algorithm can predict large displacements and the force-deflection relationship of lateral torsional buckled beams significantly faster than the finite element method. This approach is not intended to compete with finite element analysis, but rather is a supplement tool that may prove particularly useful in the early phases of design …

A Correlation-Based Method To Detect Weak Dependence, Yabing Luo

Theses and Dissertations

The focus of this thesis is an investigation of ways to detect weak dependence between two random variables X and Y. Our approach is to design tests for correlation rather than testing for dependence directly, since X and Y are not independent if they are not uncorrelated. We examined the magnified Pearson correlation after the Box-Cox transformation to determine whether X and Y are dependent. The results indicated that our approach not only has the potential to detect and evaluate the weak dependence cases that have previously been intractable, but also is conceptually simple and easy to implement.

Investigation Of Dc Motors For Electric And Hybrid Electric Motor Vehicle Applications Using An Infinitely Variable Transmission, Benjamin Carson Groen

Theses and Dissertations

Since the early 1900's demand for fuel efficient vehicles has motivated the development of electric and hybrid electric vehicles. Unfortunately, some components used in these vehicles are expensive and complex. AC motors, complex electronic controllers and complex battery management systems are currently used in electric (EV) and hybrid vehicles. This research examines various motors and speed control methods in an attempt to help designers identify which motors would be best suited for an EV powertrain application. The feasibility of using DC motors coupled with an Infinitely Variable Transmission (IVT), to obtain an innovative new electric or hybrid electric powertrain is …

The Use Of Two-Phase Molecular Dynamics Simulations To Determine The Phase Behavior And Critical Point Of Propane Molecular Models, Sonal Patel, W. Vincent Wilding, Richard L. Rowley

Faculty Publications

Molecular dynamics simulations were performed to determine two-phase configurations of model propane molecules below the critical point and in the near-critical, two-phase region. A postprocessor that uses a Monte Carlo method for determination of volumes attributable to each molecule was used to obtain density histograms of the particles from which the bulk coexisting equilibrium vapor and liquid densities were determined. This method of analyzing coexisting densities in a two-phase simulation is straightforward and can be easily implemented for complex, multisite models. Various degrees of internal flexibility in the propane models have little effect on the coexisting densities at temperatures 40 …

Investigation Of An Iron-Based Additive On Coal Pyrolysis And Char Oxidation At High Heating Rates, John M. Sowa, Thomas H. Fletcher

Faculty Publications

Iron-based catalysts have been shown to enhance coal pyrolysis and char oxidation at low to moderate temperatures and heating rates (b1250 K and 1–1000 K/s). Such catalytic activity has not been demonstrated at high heating rates and temperatures approaching pulverized coal combustion applications. The effect of an iron-based additive on coal pyrolysis and char combustion was studied in a flat-flame burner system at high particle heating rates using a Kentucky bituminous coal. Pyrolysis and char reactivity of two treated coals with different catalyst loadings were studied and compared with the untreated coal. The total volatiles yield for the treated coals …

Pyrolysis Kinetics Of A Green River Oil Shale Using A Pressurized Tga, James L. Hillier, Thomas H. Fletcher

Faculty Publications

Crushed samples of Green River Oil Shale and its kerogen extract were pyrolyzed at heating rates from 1 to 10 K/min at pressures of 1 and 40 bar and temperatures up to 1000 C. Two to four mass release peaks were observed with the major two corresponding to kerogen pyrolysis and carbonate decomposition. The transient pyrolysis data were fit with a first-order model and a Distributed Activation Energy Model (DAEM). An F-test was used to determine confidence regions and compare the kinetic parameters among the oil shale and demineralized samples, between the two pressure levels, and between the models. The …

Self Assembly In Additive Manufacturing: Opportunities And Obstacles, Nathan B. Crane, J. Tuckerman, G. N. Nielson

Faculty Publications

Purpose

Additive manufacturing offers substantial flexibility in shape, but much less flexibility in materials and functionality—particularly at small size scales. A system for automatically incorporating microscale components would enable the fabrication of objects with more functionality. This paper considers the potential of self assembly to serve as an automated programmable integration method. In particular, it addresses the ability of random self assembly processes to successfully assemble objects with high performance despite the possibility of assembly errors.

Methodology

A self-assembled thermoelectric system is taken as a sample system. The performance expectations for these systems are then predicted using modified one-dimensional models …

Effect Of Particle Size And Trench Configuration On Deposition From Fine Coal Flyash Near Film Cooling Holes, Weiguo Ai, Robert G. Laycock, Devin Rappleye, Thomas H. Fletcher

Faculty Publications

Particulate deposition experiments were performed in a turbine accelerated deposition facility to examine the effects of flyash particle size and trench configuration on deposits near film cooling holes. Deposition on two bare metal Inconel coupons was studied, with hole spacings (s/d) of 3.4 and 4.5. Two sizes of sub-bituminous coal ash particles were used, with mass mean diameter of 4 and 13 μm, respectively. The effect of a cooling trench at the exit of the cooling holes was also examined in this deposition facility. Experiments were performed at different angles of impaction. Particles were accelerated to a combustor exit flow …

Film Cooling Effectiveness And Heat Transfer Near Deposit-Laden Film Holes, Scott Lewis, Brett Barker, Jeffrey P. Bons, Weiguo Ai, Thomas H. Fletcher

Faculty Publications

Experiments were conducted to determine the impact of synfuel deposits on film cooling effectiveness and heat transfer. Scaled up models were made of synfuel deposits formed on film-cooled turbine blade coupons exposed to accelerated deposition. Three distinct deposition patterns were modeled: a large deposition pattern (maximum deposit peak = 2 hole diameters) located exclusively upstream of the holes, a large deposition pattern (maximum deposit peak = 1.25 hole diameters) extending downstream between the cooling holes, and a small deposition pattern (maximum deposit peak = 0.75 hole diameter) also extending downstream between the cooling holes. The models featured cylindrical holes inclined …

Coal Swelling Model For High Heating Rate Pyrolysis Applications, Randy C. Shurtz, Kolbein K. Kolste, Thomas H. Fletcher

Faculty Publications

Thermal swelling of coal during pyrolysis strongly influences combustion and gasification rates. Coal swelling is known to vary strongly with coal rank, heating rate, and total pressure. New experiments confirm and clarify previous observations that maximum swelling occurs for high-rank bituminous coals at heating rates slightly below 10⁴ K/s. Advanced swelling models based on bubble physics yield good qualitative trends at low heating rates, but they fail to predict observed decreases in coal swelling as particle heating rates increase beyond 10⁴ K/s. An empirical swelling correlation for computational fluid dynamics (CFD) applications that correctly describes experimentally observed trends …

The Effects Of Wind On The Flame Characteristics Of Individual Leaves, Wesley J. Cole, Mckaye H. Dennis, Thomas H. Fletcher, David R. Weise

Faculty Publications

Individual cuttings from five shrub species were burned over a flat-flame burner under wind conditions of 0.75–2.80m s^-1. Both live and dead cuttings were used. These included single leaves from broadleaf species as well as 3 to 5 cm-long branches from coniferous and small broadleaf species. Flame angles and flame lengths were determined by semi-automated measurements of video images. Additional data, such as times and temperatures corresponding to ignition, maximum flame height and burnout were determined using video and infrared images. Flame angles correlated linearly with wind velocity. They also correlated with the Froude number when either the …

Active Noise Control Of A Two-Fan Exhaust-Mounted Array Using Near-Field Control Sources And Error Sensors, Ryan Leonard Rust

Theses and Dissertations

Multiple fans are sometimes used in an array configuration to cool various types of electronic equipment. In addition to adding another noise source, using two fans with closely spaced blade passage frequencies (BPF) can create an annoying beat frequency. A two fan array with each fan having a different BPF was considered. The fans were theoretically modeled at the BPF and first harmonics. Each fan has two acoustic paths to the far field. Thus, each fan was modeled as a two source array. The first control configuration consisted of one control filter using six control sources and six error sensors …

Scanning Laser Registration And Structural Energy Density Based Active Structural Acoustic Control, Daniel Alan Manwill

Theses and Dissertations

To simplify the measurement of energy-based structural metrics, a general registration process for the scanning laser doppler vibrometer (SLDV) has been developed. Existing registration techniques, also known as pose estimation or position registration, suffer from mathematical complexity, instrument specificity, and the need for correct optimization initialization. These difficulties have been addressed through development of a general linear laser model and hybrid registration algorithm. These are applicable to any SLDV and allow the registration problem to be solved using straightforward mathematics. Additionally, the hybrid registration algorithm eliminates the need for correct optimization initialization by separating the optimization process from solution selection. …

The Use Of Building Information Modeling In Generating Hard Bid Estimates, Peter Samuel Jensen

Theses and Dissertations

Building Information Modeling has provided many benefits to the architectural, engineering, construction and facilities management communities. Many studies have been done to validate the asserted benefits, including benefits to the field of estimating. The studies on estimating are currently limited to the realm of conceptual estimates, and have only treated detailed estimates in the abstract. The purpose of this study was to determine how BIM was being used by companies in a hard bid, or detailed estimate scenario. The research team used the Deseret Towers housing project at Brigham Young University as the basis for the research. A building information …

Joining Polycrystalline Cubic Boron Nitride And Tungsten Carbide By Partial Transient Liquid Phase Bonding, Grant O. Cook Iii

Theses and Dissertations

Friction stir welding (FSW) of steel is often performed with an insert made of polycrystalline cubic boron nitride (PCBN). Specifically, MS80 is a grade of PCBN made by Smith MegaDiamond that has been optimized for the FSW process. The PCBN insert is attached to a tungsten carbide (WC) shank by a compression fitting. However, FSW tools manufactured by this method inevitably fail by fracture in the PCBN. Permanently bonding PCBN to WC would likely solve the fracturing problem and increase the life of PCBN FSW tools to be economically viable. Partial transient liquid phase (PTLP) bonding, a process used to …

Eit, Slow Light, And Sealing Methods For Embedding Rubidium Into The Arrow System, Katherine Barnett Hurd

Theses and Dissertations

Light-matter interactions are fundamentally based on the quantum mechanical principles that govern photons, electrons and other fundamental particles. One very interesting phenomenon within all of light-matter interactions is Electromagnetically Induced Transparency(EIT). This phenomenon causes an otherwise absorbing atomic transition to stop absorbing through quantum mechanical interference of probability wave functions. Corresponding to that change in absorption, will be a sudden, large change in the index of refraction. This change in the index of refraction leads to another phenomenon in which the group velocity of light can be slowed down dramatically. In the past, many researchers have been able to achieve …

Modeling And Testing Of Dna Motion For Nanoinjection, Regis Agenor David

Theses and Dissertations

A new technique, called nanoinjection, is being developed to insert foreign DNA into a living cell. Such DNA transfection is commonly used to create transgenic organisms vital to the study of genetics, immunology, and many other biological sciences. In nanoinjection, DNA, which has a net negative charge, is electrically attracted to a micromachined lance. The lance then pierces the cell membranes, and the voltage on the lance is reversed, repelling the DNA into the cell. It is shown that DNA motion is strongly correlated to ion transport through a process called electrophoresis. Gel electrophoresis is used to move DNA using …