Open Access. Powered by Scholars. Published by Universities.®
- Discipline
-
- Mechanical Engineering (1342)
- Civil and Environmental Engineering (1183)
- Electrical and Computer Engineering (758)
- Chemical Engineering (757)
- Civil Engineering (650)
-
- Computer Engineering (641)
- Other Civil and Environmental Engineering (641)
- Data Storage Systems (632)
- Environmental Engineering (629)
- Hydraulic Engineering (573)
- Construction Engineering and Management (91)
- Manufacturing (71)
- Biomedical Engineering and Bioengineering (46)
- Other Engineering (39)
- Physical Sciences and Mathematics (38)
- Social and Behavioral Sciences (34)
- Other Mechanical Engineering (33)
- Operations Research, Systems Engineering and Industrial Engineering (31)
- Education (25)
- Geography (22)
- Engineering Education (21)
- Geographic Information Sciences (20)
- Computer Sciences (16)
- Business (15)
- Medicine and Health Sciences (15)
- Arts and Humanities (14)
- Biochemical and Biomolecular Engineering (13)
- Industrial Technology (12)
- Life Sciences (12)
- Keyword
-
- UAV (104)
- FPGA (86)
- Optimization (74)
- Coal (71)
- Compliant mechanisms (59)
-
- Pyrolysis (52)
- Unmanned aircraft (52)
- Origami (47)
- Modeling (45)
- MEMS (39)
- Design (37)
- Machine learning (37)
- Remote sensing (37)
- Scatterometer (37)
- Simulation (37)
- CFD (36)
- Friction stir welding (36)
- Microfluidics (36)
- Combustion (35)
- Biomass (33)
- GIS (33)
- Liquefaction (32)
- Model predictive control (32)
- Engineering (30)
- Heat transfer (30)
- Additive manufacturing (29)
- Model (29)
- QuikSCAT (28)
- CAD (27)
- Finite element analysis (27)
- Publication Year
- Publication
-
- Theses and Dissertations (2410)
- Faculty Publications (1187)
- International Congress on Environmental Modelling and Software (629)
- Journal of Undergraduate Research (438)
- Biomedical Engineering Western Regional Conference (46)
-
- Undergraduate Honors Theses (28)
- Student Works (27)
- ScholarsArchive Data (23)
- Engineering Applications of GIS - Laboratory Exercises (21)
- Reviews, Analyses, and Instructional Studies in Electrochemistry (RAISE) (10)
- BYU Research Development Office Research Networking Conference (8)
- Directivity (5)
- Marriott Student Review (5)
- BYU West Mountain Observatory Project (2)
- Books (2)
- Brigham Young University Prelaw Review (2)
- FEAT Publications (2)
- FHSS Mentored Research Conference (1)
- Journal of Nonprofit Innovation (1)
- Library Research Grants (1)
- Library/Life Sciences Undergraduate Poster Competition 2019 (1)
- Library/Life Sciences Undergraduate Poster Competition 2022 (1)
- Publication Type
- File Type
Articles 3301 - 3330 of 4850
Full-Text Articles in Engineering
Investigation Of Internal Wave Spectra Due To Observed Interactions, Benjamin Lee Hillyard
Investigation Of Internal Wave Spectra Due To Observed Interactions, Benjamin Lee Hillyard
Theses and Dissertations
Observational data are analyzed and decomposed to reveal internal ocean waves and their interactions with one another. Particularly, the interaction of small-scale internal waves with a large inertia wave packet is examined. Using the governing internal wave equations, an analysis is made of the energy propagation of a small scale internal wave with a large-scale inertia wave. With that, an assessment is made of the frequency of occurrence of various encounter types. Next, the possibility of energy transfer during an interaction is explored. The relative energy of the small wave before interacting with the large-scale inertia wave is calculated and …
Discrete-Time Implementation, Antenna Design, And Mimo For Near-Field Magnetic Induction Communications, Ronald Brett Gottula
Discrete-Time Implementation, Antenna Design, And Mimo For Near-Field Magnetic Induction Communications, Ronald Brett Gottula
Theses and Dissertations
Near-field magnetic induction (NFMI) is a short range wireless technology that uses loop antennas coupled by a magnetic field. NFMI antennas are electrically small and thus extremely inefficient and narrow band, making system design for multi-user and high-bitrate applications challenging. The goals of this thesis are to develop a test platform suitable for NFMI antenna testing, to model, design and test NFMI antennas that have high bandwidth-efficiency, and to explore the possibility of using MIMO (multiple-input multiple-output) to increase the capacity of the NFMI channel. This thesis provides system implementations, test results, and channel modeling to aid in the design …
Investigation Of A Planetary Differential For Use As A Continuously Variable Transmission, Austin B. Randall
Investigation Of A Planetary Differential For Use As A Continuously Variable Transmission, Austin B. Randall
Theses and Dissertations
With gas prices on the rise, the demand for high-mileage and low pollution vehicles has taken on an unprecedented role in our society. The production and implementation of electric and hybrid-electric vehicles has recently been a large focus of all major automobile manufacturers. Although these new vehicles have begun to solve much of the expensive fuel consumption and air pollution problems that our economy faces, the initial cost of these vehicles has proven to still be too expensive to capture a significant portion of the market. The further advancement of this technology must not only continue to focus on better …
Investigations Of The Dry Snow Zone Of The Greenland Ice Sheet Using Quikscat, Kevin Randall Moon
Investigations Of The Dry Snow Zone Of The Greenland Ice Sheet Using Quikscat, Kevin Randall Moon
Theses and Dissertations
The Greenland ice sheet is an area of great interest to the scientific community due to its role as an important bellwether for the global climate. Satellite-borne scatterometers are particularly well-suited to studying temporal changes in the Greenland ice sheet because of their high spatial coverage, frequent sampling, and sensitivity to the presence of liquid water. The dry snow zone is the largest component of the Greenland ice sheet and is identified as the region that experiences negligible annual melt. Due to the lack of melt in the dry snow zone, backscatter was previously assumed to be relatively constant over …
Principal Components Analysis, Factor Analysis And Trend Correlations Of Twenty-Eight Years Of Water Quality Data Of Deer Creek Reservoir, Utah, Nicolas Alejandro Gonzalez
Principal Components Analysis, Factor Analysis And Trend Correlations Of Twenty-Eight Years Of Water Quality Data Of Deer Creek Reservoir, Utah, Nicolas Alejandro Gonzalez
Theses and Dissertations
I evaluated twenty-eight years (1980-2007) of spatial-temporal water quality data from Deer Creek Reservoir in Utah. The data came from three sampling points representing the lotic, transitional and lentic zones. The data included measurements of climatological, hydrological and water quality conditions at four depths; Surface, Above Thermocline, Below Thermocline and Bottom. The time frame spanned dates before and after the completion of the Jordanelle Reservoir (1987-1992), approximately fourteen miles upstream of Deer Creek. I compared temporal groupings and found that a traditional month distribution following standard seasons was not effective in characterizing the measured conditions; I developed a more representative …
Constrained Control And Optimization Of Tubular Solid Oxide Fuel Cells For Extending Cell Lifetime, Ben Spivey, John Hedengren, Thomas F. Edgar
Constrained Control And Optimization Of Tubular Solid Oxide Fuel Cells For Extending Cell Lifetime, Ben Spivey, John Hedengren, Thomas F. Edgar
Faculty Publications
Extending fuel cell lifetime is a necessary objective for reducing fuel cell power generation cost of electricity. Capital costs comprise the most significant fraction of the cost of electricity. Reducing the frequency of fuel cell replacement can be achieved by implementing a control strategy that prevents excursions into operating regions causing failure. In this paper we implement a constrained MIMO model predictive controller (MPC) to avoid the failure modes relevant for a high-temperature tubular solid oxide fuel cell (SOFC) system while performing load-following. The primary causes of failure are catalyst poisoning, fuel or air starvation, carbon deposition, and microcracking. Prior …
Investigation Of Compliant Space Mechanisms With Application To The Design Of A Large-Displacement Monolithic Compliant Rotational Hinge, Robert Mcintyre Fowler
Investigation Of Compliant Space Mechanisms With Application To The Design Of A Large-Displacement Monolithic Compliant Rotational Hinge, Robert Mcintyre Fowler
Theses and Dissertations
The purpose of this research is to investigate the use of compliant mechanisms in space applications and design, analyze, and test a compliant space mechanism. Current space mechanisms are already highly refined and it is unclear if significant improvements in performance can be made by continuing to refine current designs. Compliant mechanisms offer a promising opportunity to change the fundamental approach to achieving controlled motion in space systems and have potential for dramatic increases in mechanism performance given the constraints of the space environment. A compliant deployment hinge was selected for development after industry input was gathered. Concepts for large-displacement …
Multiple Molecule Effects On The Cooperativity Of Protein Folding Transitions In Simulations, Jacob I. Lewis, Devin J. Moss, Thomas A. Knotts Iv
Multiple Molecule Effects On The Cooperativity Of Protein Folding Transitions In Simulations, Jacob I. Lewis, Devin J. Moss, Thomas A. Knotts Iv
Faculty Publications
Though molecular simulation of proteins has made notable contributions to the study of protein folding and kinetics, disagreement between simulation and experiment still exists. One of the criticisms levied against simulation is its failure to reproduce cooperative protein folding transitions. This weakness has been attributed to many factors such as a lack of polarizability and adequate capturing of solvent effects. This work, however, investigates how increasing the number of proteins simulated simultaneously can affect the cooperativity of folding transitions — a topic that has received little attention previously. Two proteins are studied in this work: phage T4 lysozyme (Protein Data …
Performance Characteristics Of Lithium Coin Cells For Use In Wireless Sensing Systems, Yin Zhang
Performance Characteristics Of Lithium Coin Cells For Use In Wireless Sensing Systems, Yin Zhang
Theses and Dissertations
Understanding the pulsed discharge behavior of low-rate lithium coin cells in wireless sensing systems is critical to prolong the operating life and/or reduce the size of battery-powered WSs. This dissertation presents the battery transient analysis for a sensor duty cycle, experimental studies for sustained pulse discharge cycling, and investigation on recharge strategies for a battery/power harvesting hybrid system for WSs. The transient behavior of the lithium coin cells during pulse discharge and subsequent relaxation was investigated with single-pulse experiments and theoretical analysis. The voltage response for a pulsed discharge had two parts: a region of rapid voltage change and a …
Determination Of Phase Equilibria And The Critical Point Using Two-Phase Molecular Dynamics Simulations With Monte Carlo Sampling, Sonal Patel
Theses and Dissertations
The two-phase MD technique employed in this work determines the liquid and vapor phase densities from a histogram of molecular densities within phase clusters in the simulation cell using a new Monte Carlo (MC) sampling method. These equilibrium densities are then fitted in conjunction with known critical-point scaling laws to obtain the critical temperature, and the critical density. This MC post-processing method was found to be more easily implemented in code, and it is efficient and easily applied to complex, structured molecules. This method has been successfully applied and benchmarked for a simple Lennard-Jones (LJ) fluid and a structured molecule, …
Multi-User Methods For Fea Pre-Processing, Prasad Weerakoon
Multi-User Methods For Fea Pre-Processing, Prasad Weerakoon
Theses and Dissertations
Collaboration in engineering product development leads to shorter product development times and better products. In product development, considerable time is spent preparing the CAD model or assembly for Finite Element Analysis (FEA). In general Computer-Aided Applications (CAx) such as FEA deter collaboration because they allow only a single user to check out and make changes to the model at a given time. Though most of these software applications come with some collaborative tools, they are limited to simple tasks such as screen sharing and instant messaging. This thesis discusses methods to convert a current commercial FEA pre-processing program into a …
Chemical Potential Perturbation: A Method To Predict Chemical Potential Using Molecular Simulations, Stan G. Moore
Chemical Potential Perturbation: A Method To Predict Chemical Potential Using Molecular Simulations, Stan G. Moore
Theses and Dissertations
A new method, called chemical potential perturbation (CPP), has been developed to predict the chemical potential as a function of composition in molecular simulations. The CPP method applies a spatially varying external potential to the simulation, causing the composition to depend upon position in the simulation cell. Following equilibration, the homogeneous chemical potential as a function of composition can be determined relative to some reference state after correcting for the effects of the inhomogeneity of the system. The CPP method allows one to predict chemical potential for a wide range of composition points using a single simulation and works for …
A New Assessment Method To Easily Identify Areas Needing Improvement In Course-Level Learning Outcomes, Thomas Knotts, W. Vincent Wilding, William G. Pitt, Morris D. Argyle
A New Assessment Method To Easily Identify Areas Needing Improvement In Course-Level Learning Outcomes, Thomas Knotts, W. Vincent Wilding, William G. Pitt, Morris D. Argyle
Faculty Publications
A New Assessment Method to Easily Identify Areas Needing Improvement Course‐level Learning Outcomes Thomas A. Knotts IV, W. Vincent Wilding, William G. Pitt, and Morris D. Argyle Department of Chemical Engineering, Brigham Young University Assessment of student proficiency in expected outcomes, whether on the course or program level, is an important aspect of curriculum development in engineering programs. The reasons for such assessment range from desires to improve student learning to fulfilling requirements of various accreditation bodies. But regardless of the reasons, the challenge is to develop suitable metrics which can clearly identify areas which need improvement. In order to …
Developing And Assessing Leadership In Engineering Students, W. Vincent Wilding, Thomas A. Knotts, William G. Pitt, Morris D. Argyle
Developing And Assessing Leadership In Engineering Students, W. Vincent Wilding, Thomas A. Knotts, William G. Pitt, Morris D. Argyle
Faculty Publications
Developing and Assessing Leadership in Engineering Students W. Vincent Wilding, Thomas A. Knotts IV, William G. Pitt, and Morris D. Argyle Department of Chemical Engineering, Brigham Young University The Ira A. Fulton College of Engineering and Technology at Brigham Young University is focusing on five initiatives: Leadership, Innovation, Global Awareness, Character, Technical Excellence. Efforts in the realm of leadership include freshmen leadership seminars and a required sophomore course entitled Global Leadership in a Technological World. Departments within the college are expected to build on this foundation in the junior and senior years. The Chemical Engineering Department has developed an effective …
Evaluation Of Advanced Conductive Nickel Materials For Strain Sensing In Carbon Fiber Reinforced Polymers, Michael Christian Koecher
Evaluation Of Advanced Conductive Nickel Materials For Strain Sensing In Carbon Fiber Reinforced Polymers, Michael Christian Koecher
Theses and Dissertations
Due to their unique properties, carbon fiber reinforced polymers (CFRP) are becoming ever more prevalent in today's society. Unfortunately, CFRP suffer from a wide range of failure modes and structural health monitoring methods are currently insufficient to predict these failures. It is apparent that self-sensing structural health monitoring could be advantageous to protect consumers from catastrophic failure in CFRP structures. Previous research has shown that embedded nickel nanostrand nanocomposites can be used to instantaneously measure strain in carbon fiber composites, but these methods have been severely limited and can induce high stress concentrations that compromise the structural integrity of the …
Microscopic Light Field Particle Image Velocimetry, Bryce Adam Mcewen
Microscopic Light Field Particle Image Velocimetry, Bryce Adam Mcewen
Theses and Dissertations
This work presents the development and analysis of a system that combines the concepts of light field microscopy and particle image velocimetry (PIV) to measure three-dimensional velocities within a microvolume. Rectanglar microchannels were fabricated with dimensions on the order of 350-950 micrometers using a photolithographic process and polydimethylsiloxane (PDMS). The flow was seeded with fluorescent particles and pumped through microchannels at Reynolds numbers ranging from 0.016 to 0.028. Flow at Reynolds numbers in the range of 0.02 to 0.03 was seeded with fluorescent particles and pumped through microchannels. A light field microscope with a lateral resolution of 6.25 micrometers and …
Structural Properties Of Iclt Wall Panels Composed Of Beetle Killed Wood, David Edward Wilson
Structural Properties Of Iclt Wall Panels Composed Of Beetle Killed Wood, David Edward Wilson
Theses and Dissertations
Interlocking Cross Laminated Timber (ICLT) wall panels are a new wood construction product similar to Cross Laminated Timber panels. Besides being an innovative structural system, they also utilize beetle killed timber from many of the forests that have been devastated by the Mountain Pine Beetle. Three tests were performed on three ply ICLT panels measuring 8 feet (2.44m) wide, 8 feet (2.44m) tall and 8.5 inches (21.6cm) thick to determine the racking, flexural and axial strengths of the wall panels. After each test was performed the walls were disassembled and investigated for cause of failure. Using the data from the …
Mobility Of A Semiflexible Chain Confined In A Nanochannel, Douglas R. Tree, Yanwei Wang, Kevin D. Dorfman
Mobility Of A Semiflexible Chain Confined In A Nanochannel, Douglas R. Tree, Yanwei Wang, Kevin D. Dorfman
Faculty Publications
The classic results of de Gennes and Odijk describe the mobility of a semiflexible chain confined in a nanochannel only in the limits of very weak and very strong confinement, respectively. Using Monte Carlo sampling of the Kirkwood diffusivity with full hydrodynamic interactions, we show that the mobility of a semiflexible chain exhibits a broad plateau as a function of extension before transitioning to an Odijk regime, and that the width of the plateau depends on the anisotropy of the monomers. For the particular case of DNA in a high ionic strength buffer, which has highly anisotropic monomers, we predict …
Fiber Optic Monitoring Of Subsea Equipment, David Brower, John Hedengren, Cory Loegering, Alexis Brower, Karl Witherow, Karl Winter
Fiber Optic Monitoring Of Subsea Equipment, David Brower, John Hedengren, Cory Loegering, Alexis Brower, Karl Witherow, Karl Winter
Faculty Publications
Bass Lite deepwater field in the Gulf of Mexico, at water depths of approximately 2,050 m (6,750 feet), commenced operation in February 2008. Natural gas is produced from Bass Lite via a 90-km (56-mile) subsea tieback to the Devils Tower Spar. This project involved several innovations, one of which was the incorporation of a fiber optic sensing system that measures realtime temperature, pressure and strain along the pipeline length. This is a first of its kind innovation that is in actual operation.
The Composition And Morphology Of Coal Ash Deposits Collected In An Oxy-Fuel, Pulverized Coal Reactor, Curtis K. Stimpson
The Composition And Morphology Of Coal Ash Deposits Collected In An Oxy-Fuel, Pulverized Coal Reactor, Curtis K. Stimpson
Theses and Dissertations
Coal ash deposits were collected in a 160 kWth, down-fired oxy-coal reactor under staged and unstaged conditions for four different coals (PRB, Gatling, Illinois #6, and Mahoning). Concentration measurements of carbon, oxygen, sodium, magnesium, aluminum, silicon, phosphorus, sulfur, chlorine, potassium, calcium, titanium, chromium, manganese, iron, nickel, strontium, and barium were gathered from each deposit sample using scanning electron microscopy and energy dispersive spectroscopy (SEM-EDS). Backscattered electron micrographs for each deposit sample were analyzed to gather morphological data. Particle size and shape were studied for each deposit collected. The average particle sizes of the particles in upstream deposits were much larger …
Mechanical Properties And Mems Applications Of Carbon-Infiltrated Carbon Nanotube Forests, Walter C. Fazio
Mechanical Properties And Mems Applications Of Carbon-Infiltrated Carbon Nanotube Forests, Walter C. Fazio
Theses and Dissertations
This work explores the use of carbon-infiltrated carbon nanotube (CI-CNT) forests as a material for fabricating compliant MEMS devices. The impacts of iron catalyst layer thickness and carbon infiltration time are examined. An iron layer of 7nm or 10nm with an infiltration time of 30 minutes produces CI-CNT best suited for compliant applications. Average maximum strains of 2% and 2.48% were observed for these parameters. The corresponding elastic moduli were 5.4 GPa and 4.1 GPa, respectively. A direct comparison of similar geometry suggested CI-CNT is 80% more flexible than single-crystal silicon. A torsional testing procedure provided an initial shear modulus …
Automatic Discovery And Exposition Of Parallelism In Serial Applications For Compiler-Inserted Runtime Adaptation, David A. Greenland
Automatic Discovery And Exposition Of Parallelism In Serial Applications For Compiler-Inserted Runtime Adaptation, David A. Greenland
Theses and Dissertations
Compiler-Inserted Runtime Adaptation (CIRA) is a compilation and runtime adaptation strategy which has great potential for increasing performance in multicore systems. In this strategy, the compiler inserts directives into the application which will adapt the application at runtime. Its ability to overcome the obstacles of architectural and environmental diversity coupled with its flexibility to work with many programming languages and styles of applications make it a very powerful tool. However, it is not complete. In fact, there are many pieces still needed to accomplish these lofty goals. This work describes the automatic discovery of parallelism inherent in an application and …
Uv Visible Spectra Analysis Of High Temperature Water Gas Shift Catalysts Made From Iron, Lanthanum, Copper, And Chromium Oxides, Jared C. Brown
Uv Visible Spectra Analysis Of High Temperature Water Gas Shift Catalysts Made From Iron, Lanthanum, Copper, And Chromium Oxides, Jared C. Brown
Theses and Dissertations
Hydrogen is a vital component in several different chemical reactions as well as a potential fuel source for the future. The water gas shift (WGS) reaction converts CO and water to hydrogen and CO2. The objective of this work is to first, characterize the potential benefits of the addition of lanthanum oxide (lanthana) to the iron-chromium-copper (Fe-Cr-Cu) oxide catalysts industrially used in high temperature water gas shift processes, and second, analyze these catalysts using in-situ UV-Visible spectroscopy. The benefits of each component in the catalyst are discussed as well as potential benefits from the addition of lanthana. Lanthana is a …
No, Burnout, Flame Temperature, Emissivity, And Radiation Intensity From Oxycombustion Flames, Darrel Patrick Zeltner
No, Burnout, Flame Temperature, Emissivity, And Radiation Intensity From Oxycombustion Flames, Darrel Patrick Zeltner
Theses and Dissertations
This work produced the retrofit of an air-fired, 150 kW reactor for oxy-combustion which was then used in three oxy-combustion studies: strategic oxy-combustion design, oxy-combustion of petroleum coke, and air versus oxy-combustion radiative heat flux measurements. The oxy-combustion retrofit was accomplished using a system of mass flow controllers and automated pressure switches which allowed safe and convenient operation. The system was used successfully in the three studies reported here and was also used in an unrelated study. A study was completed where a novel high oxygen participation burner was investigated for performance while burning coal related to flame stability, NO, …
A Pressure Gauge Based On Gas Density Measurement From Analysis Of The Thermal Noise Of An Atomic Force Microscope Cantilever, Dongjin Seo, Mark R. Paul, Willian A. Ducker
A Pressure Gauge Based On Gas Density Measurement From Analysis Of The Thermal Noise Of An Atomic Force Microscope Cantilever, Dongjin Seo, Mark R. Paul, Willian A. Ducker
Faculty Publications
We describe a gas-density gauge based on the analysis of the thermally-driven fluctuations of an atomic force microscope (AFM) cantilever. The fluctuations are modeled as a ring-down of a simple harmonic oscillator, which allows fitting of the resonance frequency and damping of the cantilever, which in turn yields the gas density. The pressure is obtained from the density using the known equation of state. In the range 10–220 kPa, the pressure readings from the cantilever gauge deviate by an average of only about 5% from pressure readings on a commercial gauge. The theoretical description we use to determine the pressure …
A Method For Exploring Optimization Formulation Space In Conceptual Design, Shane Keawe Curtis
A Method For Exploring Optimization Formulation Space In Conceptual Design, Shane Keawe Curtis
Theses and Dissertations
Formulation space exploration is a new strategy for multiobjective optimization that facilitates both divergent searching and convergent optimization during the early stages of design. The formulation space is the union of all variable and design objective spaces identified by the designer as being valid and pragmatic problem formulations. By extending a computational search into the formulation space, the solution to an optimization problem is no longer predefined by any single problem formulation, as it is with traditional optimization methods. Instead, a designer is free to change, modify, and update design objectives, variables, and constraints and explore design alternatives without requiring …
Relative Navigation And Control Of A Hexacopter, Timothy Mclain, Randal W. Beard, Robert C. Leishman, John Macdonald
Relative Navigation And Control Of A Hexacopter, Timothy Mclain, Randal W. Beard, Robert C. Leishman, John Macdonald
Faculty Publications
This paper discusses the progress made on developing a multi-rotor helicopter equipped with a vision-based ability to navigate through an a priori unknown, GPS-denied environment. We highlight the backbone of our system, the relative estimation and control. We depart from the common practice of using a globally referenced map, preferring instead to keep the position and yaw states in the EKF relative to the current map node. This relative navigation approach allows simple application of sensor updates, natural characterization of the transformation between map nodes, and the potential to generate a globally consistent map when desired. The EKF fuses view …
The Application Of Origami To The Design Of Lamina Emergent Mechanisms (Lems) With Extensions To Collapsible, Compliant And Flat-Folding Mechanisms, Holly Greenberg
The Application Of Origami To The Design Of Lamina Emergent Mechanisms (Lems) With Extensions To Collapsible, Compliant And Flat-Folding Mechanisms, Holly Greenberg
Theses and Dissertations
Lamina emergent mechanisms (LEMs) are a subset of compliant mechanisms which are fabricated from planar materials; use compliance, or flexibility of the material, to transfer energy; and have motion that emerges out of the fabrication plane. LEMs provide potential design advantages by reducing the number of parts, reducing cost, reducing weight, improving recyclability, increasing precision, and eliminating assembly, to name a few. However, there are inherent design and modeling challenges including complexities in large, non-linear deflections, singularities that exist when leaving the planar state, and the coupling of material properties and geometry in predicting mechanism behavior. This thesis examines the …
Mesh Adaption For Efficient Multiscale Implementation Of One-Dimensional Turbulence, D. O. Lignell, A. R. Kerstein, G. Sun, E. I. Monson
Mesh Adaption For Efficient Multiscale Implementation Of One-Dimensional Turbulence, D. O. Lignell, A. R. Kerstein, G. Sun, E. I. Monson
Faculty Publications
One-Dimensional Turbulence (ODT) is a stochastic model for turbulent flow simulation. In an atmospheric context, it is analogous to single-column modeling (SCM) in that it lives on a 1D spatial domain, but different in that it time advances individual flow realizations rather than ensemble-averaged quantities. The lack of averaging enables a physically sound multiscale treatment, which is useful for resolving sporadic localized phenomena, as seen in stably stratified regimes, and sharp interfaces, as observed where a convective layer encounters a stable overlying zone. In such flows, the relevant scale range is so large that it is beneficial to enhance model …
One-Dimensional-Turbulence Simulation Of Flame Extinction And Reignition In Planar Ethylene Jet Flames, David O. Lignell, Devin Rappleye
One-Dimensional-Turbulence Simulation Of Flame Extinction And Reignition In Planar Ethylene Jet Flames, David O. Lignell, Devin Rappleye
Faculty Publications
A series of three simulations of temporally evolving, planar, nonpremixed ethylene jet flames are performed using the one-dimensional-turbulence (ODT) model. The simulations are performed at a fixed Reynolds number, but varying Damköhler numbers, under conditions that result in significant flame extinction and reignition. Results are compared to corresponding direct numerical simulations (DNSs), which exhibit 40, 70, and nearly 100% peak flame extinction among the three cases. The planar, temporal configuration is ideal for comparison and validation of the ODT model, and identical thermodynamic, transport, and kinetic models were used. The ODT model captures the jet evolution and heat …