Engineering Commons^™

The Bambow: A Bamboo-Cored Carbon-Fiber Composite Bow, Ezekiel G. Merriam

Student Works

Archery is a sport that has benefited from thousands of years of development. Starting with primitive stick-bows, ancient people found they could propel projectiles larger distances and with more effectiveness than by hand or with other mechanical aids. Over the centuries different cultures adopted and advanced different aspects of the technology, including materials, geometry, and manufacturing methods. In the Mechanical Engineering Department at BYU, Nephi's Steel Bow Competition is held annually to challenge engineering students to test their knowledge of mechanics and materials. As a past participant in this competition, I felt building an advanced composite bow would be an …

The Influence Of Season, Heating Mode And Slope Angle On Wildland Fire Behavior, Jonathan R. Gallacher

Theses and Dissertations

Wildland fire behavior research in the last 100 years has largely focused on understanding the physical phenomena behind fire spread and on developing models that can predict fire behavior. Research advances in the areas of live-fuel combustion and combustion modeling have highlighted several weaknesses in the current approach to fire research. Some of those areas include poor characterization of solid fuels in combustion modeling, a lack of understanding of the dominant heat transfer mechanisms in fire spread, a lack of understanding regarding the theory of live-fuel combustion, and a lack of understanding regarding the behavior of flames near slopes. In …

Arctic Sea Ice Classification And Soil Moisture Estimation Using Microwave Sensors, David Brian Lindell

Theses and Dissertations

Spaceborne microwave sensors are capable of estimating various properties of many geophysical phenomena, including the age and extent of Arctic sea ice and the relative soil moisture over land. The measurement and classification of such geophysical phenomena are used to refine climate models, localize and predict drought, and better understand the water cycle. Data from the active Ku-band scatterometers, the Quick Scatterometer (QuikSCAT), and the Oceansat-2 Scatterometer (OSCAT), are here used to classify areas of first-year and multiyear Arctic sea ice using a temporally adaptive threshold on reported radar backscatter values. The result is a 15-year data record of daily …

Inversion Characteristics Of A Buoyant Cylindrical Puck During Oblique Water Impact, Zachary Crawford Smith

Theses and Dissertations

The Apollo Command Module had a tendency to flip over upon impact with the ocean surface after returning from space (9/19 times). In an effort to better characterize the inversion process for future water landing vehicles, experimental results for a simplified buoyant cylindrical puck impacting the water surface are presented. This study focuses on the dependence of inversion upon vertical velocity, horizontal velocity, and the pitch angle of the puck relative to the free surface. High-speed images reveal an asymmetric cavity that forms upon water impact. The asymmetric cavity then collapses, applying a moment, which can be sufficient to invert …

Wind Plant System Engineering Through Optimization Of Layout And Yaw Control, Paul Fleming, Andrew Ning, Pieter Gebraad, Katherine Dykes

Faculty Publications

Recent research has demonstrated exciting potential for wind plant control systems to improve the cost of energy of wind plants. Wind plant controls seek to improve global wind plant performance over control systems in which each turbine optimizes only its individual performance by accounting for the way wind turbines interact through their wakes. Although these technologies can be applied to existing wind plants, it is probable that the maximum benefit would be derived by designing wind plants with these capabilities in mind. In this paper, we use system engineering approaches to perform coupled wind plant controls and position layout optimizations …

A Comprehensive Python Toolkit For Harnessing Cloud-Based High-Throughput Computing To Support Hydrologic Modeling Workflows, Scott D. Christensen

Theses and Dissertations

Advances in water resources modeling are improving the information that can be supplied to support decisions that affect the safety and sustainability of society, but these advances result in models being more computationally demanding. To facilitate the use of cost- effective computing resources to meet the increased demand through high-throughput computing (HTC) and cloud computing in modeling workflows and web applications, I developed a comprehensive Python toolkit that provides the following features: (1) programmatic access to diverse, dynamically scalable computing resources; (2) a batch scheduling system to queue and dispatch the jobs to the computing resources; (3) data management for …

Perforated Hollow Core Waveguides For Alkali Vapor-Cells And Slow Light Devices, Matthieu C. Giraud Carrier

Theses and Dissertations

The focus of this work is the integration of alkali vapor atomic vapor cells into common silicon wafer microfabrication processes. Such integrated platforms enable the study of quantum coherence effects such as electromagnetically induced transparency, which can in turn be used to demonstrate slow light. Slow and stopped light devices have applications in the optical communications and quantum computing fields. This project uses hollow core anti-resonant reflecting optical waveguides (ARROWs) to build such slow light devices. An explanation of light-matter interactions and the physics of slow light is first provided, as well as a detailed overview of the fabrication process. …

Microfluidic Devices And Biosensors, Long-Fang Tsai

Theses and Dissertations

My research broadly covers various important aspects of microfluidic devices and biosensors. Specifically, this dissertation reports: (1) a new and effective room temperature method of bonding polydimethylsiloxane (PDMS) microfluidics to substrates such as silicon and glass, (2) a new microfluidic pump concept and implementation specifically designed to repeatedly drive a small sample volume (<1 µL) very rapidly (~500 µL/min) through a sensor-containing flow channel to significantly decrease sensor response time through advection-driven rather than diffusion-driven mass transport, (3) use of a new microfluidic material based on polyethylene glycol diacrylate (PEGDA) to implement impedance-based dynamic nanochannel sensors for protein sensing, and (4) an investigation of galvanoluminescence and how to avoid it for conditions important to fluorescence-based dielectrophoresis (DEP) microfluidic biosensors. Over the last decade, the Nordin research group has developed a lab-on-a-chip (LOC) biosensor based on silicon photonic microcantilever arrays integrated with polydimethylsiloxane (PDMS) microfluidics for protein biomarker detection. Integration requires reliable bonding at room temperature with adequate bond strength between the PDMS element and microcantilever sensor substrate. The requirement for a room temperature process is particularly critical because microcantilevers must be individually functionalized with antibody-based receptor molecules prior to bonding and cannot withstand significant heating after functionalization. I developed a new room temperature bonding method using PDMS curing agent as an intermediate adhesive layer. Two curing agents (Sylgard 184 and 182) were compared, as well as an alternate UV curable adhesive (NOA 75). The bond strength of Sylgard 184 was found to be stronger than Sylgard 182 under the same curing conditions. Overnight room temperature curing with Sylgard 184 yields an average burst pressure of 433 kPa, which is more than adequate for many PDMS sensor devices. In contrast, UV curable epoxy required a 12 hour bake at 50 °C to achieve maximum bond strength, which resulted in a burst pressure of only 124 kPa. In many biosensing scenarios it is desirable to use a small sample volume (<1 µL) to detect small analyte concentrations in as short a time as possible. I report a new microfluidic pump to address this need, which we call a reflow pump. It is designed to rapidly pump a small sample volume back and forth in a flow channel. Ultimately, the flow channel would contain functionalized sensor surfaces. The rapid flow permits use of advection-driven mass transport to the sensor surfaces to dramatically reduce sensor response times compared to diffusion-based mass transport. Normally such rapid flow would have the effect of decreasing the fraction of analyte molecules in the volume that would see the sensor surfaces. By configuring the pump to reflow fluid back and forth in the flow channel, the analyte molecules in the small sample volume are used efficiently in that they have many opportunities to make it to the sensor surfaces. I describe a 3-layer PDMS reflow pump that pumps 300 nL of fluid at 500 µL/min for 15 psi actuation pressure, and demonstrate a new two-layer configuration that significantly simplifies pump fabrication. Impedance-based nanochannel sensors operate on the basis of capturing target molecules in nanochannels such that impedance through the nanochannels is increased. While simple in concept, the response time can be quite long (8~12 hours) because the achievable flow rate through a nanochannel is very limited. An approach to dramatically increase the flow rate is to form nanochannels only during impedance measurements, and otherwise have an array of nanotrenches on the surface of a conventional microfluidic flow channel where they are exposed to normal microfluidic flow rates. I have implemented such a dynamic nanochannel approach with a recently-developed microfluidic material based polyethylene glycol diacrylate (PEGDA). I present the design, fabrication, and testing of PEGDA dynamic nanochannel array sensors, and demonstrate an 11.2 % increase in nanochannel impedance when exposed to 7.2 µM bovine serum albumin (BSA) in phosphate buffered saline (PBS). Recently, LOC biosensors for cancer cell detection have been demonstrated based on a combination of dielectrophoresis (DEP) and fluorescence detection. For fluorescence detection it is critical to minimize other sources of light in the system. However, reported devices use a non-noble metal electrode, indium tin oxide (ITO), to take advantage of its optical transparency. Unfortunately, use of non-noble metal electrodes can result in galvanoluminescence (GL) in which the AC voltage applied to the electrodes to achieve DEP causes light emission, which can potentially confound the fluorescence measurement. I designed and fabricated two types of devices to examine and identify conditions that lead to GL. Based on my observations, I have developed a method to avoid GL that involves measuring the impedance spectrum of a DEP device and choosing an operating frequency in the resistive portion of the spectrum. I also measure the emission spectrum of twelve salt solutions, all of which exhibited broadband GL. Finally, I show that in addition to Au, Cr and Ni do not exhibit GL, are therefore potentially attractive as low cost DEP electrode materials.

Finite Element Modeling Of Shallow Embedded Connection Stiffness, Trevor Jones, Dr. Paul Richards

Journal of Undergraduate Research

Shallowly embedded connections are a common and important connection of steel columns to reinforced concrete foundations, which can increase the building’s overall stiffness and strength. Until now, their contributions have been neglected because they are hard to quantify and study. Previous research at BYU (Barnwell 2015) has shown that the strength and stiffness available in these connections is greater than was previously assumed. A thorough understanding of these desirable properties would allow engineers to design buildings that are more cost-effective.

Thermal Properties Of Natural-Colored And Darkened Portland Cement Concrete Pavement, Tenli Waters, W. Spencer Guthrie

Journal of Undergraduate Research

The purpose of this project was to measure thermal properties of natural-colored and darkened portland cement concrete in order to explain observations from field data already collected. While portland cement concrete pavement offers a durable surface and long service life when designed and constructed properly, selected concrete pavement sections require expensive winter maintenance treatments to clear snow and ice. One method of potentially reducing winter maintenance costs is darkening the concrete pavement. Darkening the concrete reduces its albedo, or whiteness, and should therefore promote higher pavement surface temperatures through increased absorption of radiation energy from the sun. In winter, darkened …

Girl’S Cybersecurity Camp, Sarah Cunha, Dale Rowe

Journal of Undergraduate Research

In 2015, the BYU Cybersecurity Research Lab (CSRL) held its first annual summer camp for Girls aged 14-18. A total of 38 girls attended the week’s activities and workshops. While over 75% of girls indicated they had taken a computing-related class, only 40% reported any significant interest in cybersecurity prior to the summercamp with 10% believing they had some experience in the field. At the conclusion of the camp, 80% of attendees reported a significant interest in the field with 100% of attendees interested in attending a similar event again.

High-Resolution Soil Moisture Estimation Using Ascat, Kevin Tew, Michael Scott

Journal of Undergraduate Research

NASA’s Decadal Survey emphasizes the importance of soil moisture measurements, citing their significance in predicting natural hazards and the role of soil moisture levels in the water and carbon cycles [1]. Soil moisture estimates are used for a variety of applications including drought detection, flood and landslide forecasts, crop yield monitoring, and rain precipitation models [1]–[4]. Orbiting sensors provide an effective way to measure soil moisture globally because measurements of each area can be taken at a relatively high revisit frequency (typically one to two days). These sensors are generally able to measure soil moisture parameters despite cloud coverage and, …

Single Ion Detection For Mass Spectrometry Using Low Capacitance Mosfets, Matthew Hamblin, Aaron Hawkins

Journal of Undergraduate Research

Mass spectrometry is an important tool for analytical chemistry that allows the chemical composition of a compound to be determined. In order to do so, it separates the compound into ions, and then detects the number of ions of different masses.

The charge on a single ion is very small, making it difficult to measure. In order to overcome this, current mass spectrometers must use methods such as electron multipliers to create a cascading effect of electrons until a measurable charge is reached or cryodetectors that measure the thermal change of an ion hit at low temperatures.¹ Using methods …

Voltammetric Analysis Of Mixtures Of Molten Eutectic Licl-Kcl Containing Lacl3 And Thcl4 For Concentration And Diffusion Coefficient Measurement, Zhong-Hang Wang, Devin Rappleye, Michael F. Simpson

Faculty Publications

Several electrochemical techniques, including cyclic voltammetry (CV), chronopotentiometry-open circuit potential (CP-OCP), chronoamperometry (CA) and normal pulse voltammetry (NPV) were applied to the eutectic LiCl-KCl melt containing LaCl₃ and ThCl₄ at 773K. The dependence of diffusion coefficient of La(III) on concentration of LaCl₃ was investigated by using CV, CP and CA. As the concentration of LaCl3 increases, the D_La(III) value obtained from CV gradually decreases, while the values derived from CA and CP exhibit a dome-shaped variation trend. In the LiCl-KCl-LaCl₃-ThCl₄ system, the diffusion coefficients of La(III) and Th(IV) are both approximately constant …

Laboratory Exercise- Mapping The Risk Of Structural Failure In Schools Due To An Earthquake, Joel Barker, Kimberly Sowards, Casey Webb

Engineering Applications of GIS - Laboratory Exercises

Utah’s present geology has been greatly dictated by tectonic stresses that have occurred over the last 0.7 Ga. A determining factor in much of this Geology is the Hingeline that runs through Salt Lake County. Throughout the history of the western North America, this has been an important weak zone. It is no surprise that this same zone is now home to the Wasatch Fault System, which accommodates some of the extension of Western North America. The steep mountains facing west toward Salt Lake City were formed from the tectonic processes of the Fault. The Wasatch Fault is a normal …

Laboratory Exercise X – Most Dangerous Places To Live In The United States Based On Natural Disasters, Joshua Alpers, Luke Kevan, Santiago Tovar

Engineering Applications of GIS - Laboratory Exercises

This laboratory assignment simulates the most dangerous places to live in the United States based on natural disasters. The natural disasters that will be used in this assignment include wild fires, earthquakes, landslides, hurricanes, tornadoes, and flooding. These inputs will be required in creating a heat map of the United States showing what locations are most likely to have a high probability of natural disasters.

Laboratory Exercise – Ideal Locations For A Family, Benjamin Barrett, Colin Esplin, Chris Garcia

Engineering Applications of GIS - Laboratory Exercises

Upon the successful completion of a college degree, many students (and their families) are offered job positions in various locations throughout the Unites States. As a result, these young families are tasked with the challenge of finding a suitable place to live in an area they are completely unfamiliar with. By using a model in ArcMap this task can be made much easier. In this lab a model will be created in ArcGIS Model Builder along with a corresponding map showing suitable locations.

Final Laboratory Project – Emergency Landing Site Map, John Chadwick, Daniel Pope, Todd Weichers

Engineering Applications of GIS - Laboratory Exercises

Utah County is constantly developing and expanding. New developments require new roads, new power lines, and changes to existing topography. GIS data is maintained and made available for the state of Utah by Utah AGRC (Automated Geographic Reference Center). GIS can be used to make an easy to update map that will display the current situation of roads, power lines, population density, and terrain. In this exercise a model will be created that will execute to create a map that will display safe emergency landing sites for recreational aircraft in Utah County.

Laboratory Exercise – Determining Evacuation Route For Deer Creek Dam Failure, Eleise Hinton, Matt Randall, Brian Packer

Engineering Applications of GIS - Laboratory Exercises

Deer Creek Reservoir holds a volume of approximately 153,000 acre-ft of water. All of this water is held back by Deer Creek dam. Below the dam, the Provo River flows through Provo Canyon and down into Provo before terminating at Utah Lake. While the chance of a dam break is considered unlikely, an extreme event such as a major earthquake could trigger a break. In the case of a dam break, residents of Provo who live in the flood path will need to know where to evacuate. This exercise will create a model to show the nearest evacuation sites for …

Laboratory Exercise — Safety On Roads, Elise Estep, Kyungmin Kim, Danielle Nixon

Engineering Applications of GIS - Laboratory Exercises

In transportation study area, safety is a great issue. GIS is appropriate to perform spatial analysis the accident history in define area. Specifically, GIS allow researchers to find an area or road segment that have high probability of any type of car accident such as Vehicle to Vehicle, Vehicle to Pedestrian, and Vehicle to Bicycle.

Final Laboratory Project - Finding The Ideal Camping Location In The Uintas, Jeffrey Baker, Josh Curtis, Ryan Egbert

Engineering Applications of GIS - Laboratory Exercises

GIS is used extensively by the United States Forest Service in mapping and research. Many resources are available online including raster data and shapefiles. The use of GIS tools allows for analyzing entire forests and finding specific points within large areas that meet certain criteria. The Ashley National Forest, High Uinta Mountains Wilderness, in northeastern Utah contains many shapefiles including roads, forest, highway, points of interest, lakes, streams, etc. The purpose of this lab is to use these available datasets to identify ideal locations to set up camp in the Uinta Mountains.

Child Safety Near Pot Shops In Denver, Jacob Flansberg, Elise Jackson, Amelia Theobald

Engineering Applications of GIS - Laboratory Exercises

Some major factors in deciding where one’s family should live include relative safety of the neighborhood, available green space such as parks and schools, grocery stores, and other commercial retail in the area. With the legalization of marijuana in states such as Colorado, proximity of these marijuana dispensaries has become another factor. The Normalized Difference Vegetation Index (NDVI) can be used as a measure of vegetation, and to determine areas with high levels of irrigated vegetation. Using ArcGIS Modelbuilder, the data from an NDVI analysis can be used to determine the proximity of marijuana shops to these types of greenspaces …

Real-Time Beamformer Development And Analysis Of Weak Signal Detection With Interference Mitigation For Phased-Array Feed Radio Astronomy, James Michael Brady

Theses and Dissertations

In recent years, the Brigham Young University (BYU) Radio Astronomy Systems group has developed phased-array feeds and the data acquisition processing systems necessary to perform radio astronomy observations. This thesis describes the development and testing of a real-time digital beamforming system that reduces both the time required to process phased-array feed data and the disk space used to record this data compared to post-processing beamforming systems. A real-data experiment is also discussed in this thesis, which focuses on some of the data post-processing required for one of BYU's data acquisition systems.Radio-frequency interference mitigation techniques for phased-array feed radio astronomy have …

Creating Rigid Foldability To Enable Mobility Of Origami-Inspired Mechanisms, Alden Yellowhorse, Larry L. Howell

Faculty Publications

Rigidly foldable origami crease patterns can be translated into corresponding rigid mechanisms with at least one degree of freedom. However, origami crease patterns of interest for engineering applications are not always rigidly foldable, and designers trying to adapt a crease pattern may be confronted with the need to add more mobility to their design. This paper presents design guidelines for making alterations to a crease pattern to make it rigidly foldable. Adding creases, removing panels and splitting creases are presented as potential alterations for increasing mobility, and approaches for determining the position and number of alterations are discussed. This paper …

Facilitating Deployable Mechanisms And Structures Via Developable Lamina Emergent Arrays, Larry L. Howell, Robert J. Lang, Spencer P. Magleby, Todd G. Nelson, Nathan A. Pherson

Faculty Publications

A method is presented utilizing networks of lamina emergent joints, known as lamina emergent arrays, to accommodate large-curvature developable structures suited to deployable applications. By exploiting the ruling lines in developable surfaces, this method enables developable structures and mechanisms that can be manufactured with two-dimensional geometry and yet have a greater range of elastic motion than is possible with a solid sheet of material. Aligning the joints to the ruling lines also biases the structure to a specific deployment path. A mathematical model is developed to describe the resulting stiffness of the structure employing the lamina emergent arrays and equations …

Global Sensitivity Analysis For A Comprehensive Char Conversion Model In Oxy-Fuel Conditions, Troy Michael Holland, Thomas H. Fletcher

Faculty Publications

Oxy-fired coal combustion is a promising potential carbon capture technology. Predictive CFD simulations are valuable tools in evaluating and deploying oxy-fuel and other carbon capture technologies either as retrofit technologies or for new construction. However, accurate predictive simulations require physically realistic submodels with low computational requirements. In particular, comprehensive char oxidation and gasification models have been developed that describe multiple reaction and diffusion processes. This work focuses on the sensitivity of a recent comprehensive char conversion code named CCK, which treats surface oxidation and gasification reactions as well as the processes such as film diffusion, pore diffusion, ash encapsulation, and …

Integration Of Advanced Stiffness-Reduction Techniques Demonstrated In A 3d-Printable Joint, Larry L. Howell, Ezekiel G. Merriam, Kyler A. Tolman

Faculty Publications

his work details the integration of three distinct methods for altering the stiffness of compliant joints: lattice flexures, compound joints, and static balancing. The methodology for applying these strategies is discussed in detail. Lattice flexures are a flexure modification that leads to low motion-direction bending stiffness. Compound joints improve a compliant joint’s load-carrying ability and off-axis stiffness. Static balancing in this case is achieved through the addition of an auxiliary energy storage device. To statically balance a compound lattice-flexured cross-axis flexural pivot, the load-dependent stiffness behavior of a cross-axis flexural pivot (CAFP) with two lattice flexure types is determined. A …

Compound Joints: Behavior And Benefits Of Flexure Arrays, Larry L. Howell, Ezekiel G. Merriam, Jason M. Lund

Faculty Publications

Because compliant mechanisms achieve their motion through deflection of flexible members, they have a limited range of motion and finite stiffness. Many common flexure geometries also suffer from a non-stationary center of rotation. These properties can be obstacles to their adoption in applications that require large displacements, low stiffness, or stationary centers of rotation. This work presents the concept of compound flexures: by assembling arrays of flexures, we can increase range of motion, decrease stiffness, and reduce center shift. We first develop the theory behind some of the basic behavior of compound joints. Then finite element analysis is used to …

Airborne Collision Detection And Avoidance For Small Uas Sense And Avoid Systems, Laith Rasmi Sahawneh

Theses and Dissertations

The increasing demand to integrate unmanned aircraft systems (UAS) into the national airspace is motivated by the rapid growth of the UAS industry, especially small UAS weighing less than 55 pounds. Their use however has been limited by the Federal Aviation Administration regulations due to collision risk they pose, safety and regulatory concerns. Therefore, before civil aviation authorities can approve routine UAS flight operations, UAS must be equipped with sense-and-avoid technology comparable to the see-and-avoid requirements for manned aircraft. The sense-and-avoid problem includes several important aspects including regulatory and system-level requirements, design specifications and performance standards, intruder detecting and tracking, …

Aerodynamic Performance Characterization Of Leading Edge Protrusions On Small Propellers, Kevin Moore, Andrew Ning

Faculty Publications

The relatively large tubercles or protruding bumps on the leading edge of the humpback whale fin create counter-rotating chordwise vortices. At high Reynolds numbers, these vortices have been shown to delay stall with minimal effect on drag. The range of Reynolds numbers that these types of vortices form is unknown, and so an investigation of the potential for an increased envelope of operation for small aircraft propellers was done. For the cases tested in this report no benefits were observed. The addition of leading edge protrusions decreased propeller performance in both efficiency and thrust. Because of the inherent restrictions on …