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Articles 511 - 540 of 1342

Full-Text Articles in Mechanical Engineering

An Experimental Study Of Bio-Inspired Force Generation By Unsteady Flow Features, Wesley N. Fassmann May 2014

An Experimental Study Of Bio-Inspired Force Generation By Unsteady Flow Features, Wesley N. Fassmann

Theses and Dissertations

As the understanding of the workings of the biological world expands, biomimetic designs increasingly move into the focus of engineering research studies. For this thesis, two studiesinvolving leading edge vortex generation for lift production as observed in nature were explored intheir respective flow regimes. The first study focused on the steady state analysis of streamwise vortices generated byleading edge tubercles of an adult humpback whale flipper. A realistic scaled model of a humpbackflipper was fabricated based on the 3D reconstruction from a sequence of 18 images taken whilecircumscribing an excised flipper of a beached humpback whale. Two complementary modelswith smooth …

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Tailsitter Attitude Control Using Resolved Tilt-Twist, Timothy Mclain, Jason M. Beach, Matthew E. Argyle, Randall W. Beard, Stephen Morris May 2014

Tailsitter Attitude Control Using Resolved Tilt-Twist, Timothy Mclain, Jason M. Beach, Matthew E. Argyle, Randall W. Beard, Stephen Morris

Faculty Publications

The tailsitter aircraft merges the endurance and speed of fixed-wing aircraft with the flexibility and VTOL abilities of rotorcraft. Because of the requirement to be functional at a full range of attitudes, quaternions are typically employed to calculate attitude error. Attitude control is then accomplished by using the vector component of the error quaternion to drive flight control surfaces. This paper demonstrates that this method of driving the flight control surfaces can be suboptimal for tailsitter type aircraft and can lead to undesired vehicle movement. An alternate method of calculating attitude error called resolved tilt-twist is improved and validated. The …

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Stability Of N=6 Normal And Right-Angled Kaleidocycles Under The Influence Of Energy Elements, Brett Rowberry, Dr. Larry Howell Apr 2014

Stability Of N=6 Normal And Right-Angled Kaleidocycles Under The Influence Of Energy Elements, Brett Rowberry, Dr. Larry Howell

Journal of Undergraduate Research

Normal and right-angled n=6 kaleidocycles are structures composed of six tetrahedra. They are capable of continuous rotation while only requiring 240° of rotation on each joint between adjacent tetrahedra. Because of this fact, kaleidocycles may be made fully compliant with no moving parts. Having continuous rotation in a monolithic fully compliant structure is rare, if not unique. One consequence of having compliant joints is that as they are flexed from their unstrained positions, energy is stored. As the kaleidocycle is rotated, energy is stored and released from each of the joints in a complex manner. The purpose of this research …

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Design Of A Robot Head For An Assistive Robot Used In The Clinical Treatment Of Children With Autism, Jacob Robinson, Dr. Mark Colton Apr 2014

Design Of A Robot Head For An Assistive Robot Used In The Clinical Treatment Of Children With Autism, Jacob Robinson, Dr. Mark Colton

Journal of Undergraduate Research

Autism is a spectrum disorder that is characterized by an impairment of the child’s social relationships, communication skills, and imaginative thought, resulting in a decreased quality of life for the child and his or her family, as well as significant economic costs to society. Although clinical treatment has helped some autistic children learn social skills, many others do not respond well to clinical treatment. Some research groups have investigated the use of robots as a tool to help therapists connect to the patient easier. Autistic children are more inclined to interact with a mechanical device because they exhibit repeatable actions …

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An Investigation Of Methods For Actuating Robot Arms: Direct Vs. Pulley Vs. Bowden Cable Actuation Methods, Dallin Swiss, Dr. Mark Colton Apr 2014

An Investigation Of Methods For Actuating Robot Arms: Direct Vs. Pulley Vs. Bowden Cable Actuation Methods, Dallin Swiss, Dr. Mark Colton

Journal of Undergraduate Research

A group of BYU researchers and therapists designed a robot named “Troy” for use in studies to investigate robot-assisted therapy for children with autism [1]. Troy was considered effective and successful but studies suggest that developing a new robot with greater realism and additional capabilities may promote greater clinical benefits [2]. The next robot must be safer and enable physical interaction between the robot and child. This can be done by controlling the weight, speed and flexibility of the robot arms. In particular, reducing their weight would reduce the inertial forces put on the child when interacting with the robot

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Measuring Combustion Efficiency Of Improved Cookstoves And Associated Air Quality, Whitney Steed, Erin Hamson, Jeff Lord, Dr. Matt Jones Apr 2014

Measuring Combustion Efficiency Of Improved Cookstoves And Associated Air Quality, Whitney Steed, Erin Hamson, Jeff Lord, Dr. Matt Jones

Journal of Undergraduate Research

Statistics report that approximately three billion people in the world prepare their meals using solid fuels1. The incomplete combustion that comes from burning these solid fuels creates harmful fumes and particulate matter that damage human health. Our goal was to create standard methods to measure progress towards cleaner stove emissions, focusing on cookstoves in Peru. These consistent testing procedures will allow designers to assess the impact of design changes on cookstoves by using them to measure the combustion efficiency of biomass cookstoves and to measure the indoor air quality in homes where biomass cookstoves are used.

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Direct Generation Of Smart Pareto Sets In Multiobjective Optimization, Braden Hancock, Dr. Christopher A. Mattson Apr 2014

Direct Generation Of Smart Pareto Sets In Multiobjective Optimization, Braden Hancock, Dr. Christopher A. Mattson

Journal of Undergraduate Research

In October 2013, we proposed the development of a method to directly generate smart Pareto sets of solutions in multiobjective optimization problems. Thanks to the opportunity that we received to pursue this research through an ORCA grant, we were able to develop that technology and disseminate it in the scientific community. The results of this research include a peer-reviewed journal article, a professional conference paper, a regional student conference paper, and an Honors thesis.

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Influence Of Intermediate Lamina Propria Composition On Synthetic Vocal Fold Vibration: A Comparison Of The Epi And Stiff Ligament Models, Ryan Jenkins, Dr. Scott Thomson Apr 2014

Influence Of Intermediate Lamina Propria Composition On Synthetic Vocal Fold Vibration: A Comparison Of The Epi And Stiff Ligament Models, Ryan Jenkins, Dr. Scott Thomson

Journal of Undergraduate Research

The vocal folds are two multi-layered regions of tissue located in the larynx that vibrate as air flows past from the lungs. This vibration is the basis of voiced speech, one of mankind’s primary means of expression. Due to a complex fluid-structure-acoustic interaction and the inaccessibility of in vivo tissue for observation, synthetic models have been developed and used to study different aspects of the mechanics of speech production. This project compared the performance of two self-oscillating synthetic vocal fold models that differed in their composition of an internal tissue layer called the intermediate layer of the lamina propria. Until …

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An Analytical Model For Heat Transfer Through A Thermoelectric Device Used In Waste Heat Recovery, Zachary Smith, Dr. Matthew Jones Apr 2014

An Analytical Model For Heat Transfer Through A Thermoelectric Device Used In Waste Heat Recovery, Zachary Smith, Dr. Matthew Jones

Journal of Undergraduate Research

A considerable amount of energy that is produced in a typical power generation process is rejected to the environment as low-grade waste heat. This heat is rejected at a temperature that is difficult to efficiently convert into electricity. One promising method of recovering this waste heat is through the use of thermoelectric generators (TEGs) that operate by means of the Seebeck effect. Effort has previously been placed in predicting the power output of TEGs. With knowledge of the temperature differential across a thermoelectric device and the properties of the electrical components the device is connected to, the electrical power output …

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Biomechanical Applications And Modeling Of Quantum Nano-Composite Strain Gauges, Taylor David Remington Apr 2014

Biomechanical Applications And Modeling Of Quantum Nano-Composite Strain Gauges, Taylor David Remington

Theses and Dissertations

Biological tissues routinely experience large strains and undergo large deformations during normal physiologic activity. Biological tissue deformation is well beyond the range of standard strain gauges, and hence must often be captured using expensive and non-portable options such as optical marker tracking methods that may rely upon significant post-processing. This study develops portable gauges that operate in real time and are compatible with the large strains seen by biological materials. The new gauges are based on a relatively new technique for quantifying large strain in real-time (up to 40 %) by use of a piezoresistive nano-composite strain gauge. The nano-composite …

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Relative Navigation Approach For Vision-Based Aerial Gps-Denied Navigation, Timothy Mclain, Randal W. Beard, Robert C. Leishman Apr 2014

Relative Navigation Approach For Vision-Based Aerial Gps-Denied Navigation, Timothy Mclain, Randal W. Beard, Robert C. Leishman

Faculty Publications

GPS-denied aerial flight is a challenging research problem and requires knowledge of complex elements from several distinct disciplines. Additionally, aerial vehicles can present challenging constraints such as stringent payload limits and fast vehicle dynamics. In this paper we propose a new architecture to simplify some of the challenges that constrain GPS-denied aerial flight. At the core, the approach combines visual graph-SLAM with a multiplicative extended Kalman filter. More importantly, for the front end we depart from the common practice of estimating global states and instead keep the position and yaw states of the MEKF relative to the current node in …

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Aerial Rendezvous Of Small Unmanned Aircraft Using A Passive Towed Cable System, Timothy Mclain, Randall W. Beard, Joseph W. Nichols, Liang Sun Mar 2014

Aerial Rendezvous Of Small Unmanned Aircraft Using A Passive Towed Cable System, Timothy Mclain, Randall W. Beard, Joseph W. Nichols, Liang Sun

Faculty Publications

A method for aerial rendezvous of small unmanned aircraft systems is proposed. The system includes placing a passively towed drogue into an orbit that is suitable for a small unmanned aircraft systems to follow, and a seeker guidance method for use with a monocular camera mounted on the centerline of the unmanned aircraft systems. The principle contributions of the work include a method for controlling the drogue path in moderate winds by manipulating the mothership orbit and airspeed, and a vision-based nonlinear pursuit tracking method that uses pitch rate and roll commands to guide the unmanned aircraft systems to an …

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Automated Tracking And Estimation For Control Of Non-Rigid Cloth, Marc D. Killpack Mar 2014

Automated Tracking And Estimation For Control Of Non-Rigid Cloth, Marc D. Killpack

Faculty Publications

This report is a summary of research conducted on cloth tracking for automated textile manufacturing during a two semester long research course at Georgia Tech. This work was completed in 2009. Advances in current sensing technology such as the Microsoft Kinect would now allow me to relax certain assumptions and generally improve the tracking performance. This is because a major part of my approach described in this paper was to track features in a 2D image and use these to estimate the cloth deformation. Innovations such as the Kinect would improve estimation due to the automatic depth information obtained when …

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U-Pu-Zr Alloy Design By Ternary Potts-Phase Field Modeling, Jordan Jeffrey Cox Mar 2014

U-Pu-Zr Alloy Design By Ternary Potts-Phase Field Modeling, Jordan Jeffrey Cox

Theses and Dissertations

U-Pu-Zr nuclear fuels experience a redistribution of constituents and a number of phase transformations when subjected to the thermal gradient present in nuclear reactors. This redistribution and phase separation leads to several undesirable fuel performance issues. In an effort to better understand how different alloys compositions are affected by this thermal gradient, we utilize the recently introduced Hybrid Potts-phase Field Method to study the U-Pu-Zr system. The recently introduced Hybrid method couples microstructural and compositional evolutions of a system so that the two phenomena can be studied together rather than separately, as is frequently done. However, simulation of the U-Pu-Zr …

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Aircraft Route Optimization For Formation Flight, Jia Xu, Andrew Ning, Geoffrey Bower, Ilan Kroo Mar 2014

Aircraft Route Optimization For Formation Flight, Jia Xu, Andrew Ning, Geoffrey Bower, Ilan Kroo

Faculty Publications

We quantify the fuel and cost benefits of applying extended formation flight to com- mercial airline operations. Central to this study is the development of a bi-level, mixed integer-real formation flight optimization framework. The framework has two main components: 1) a continuous domain aircraft mission performance optimization and 2) an integer optimization component that selects the best combination of optimized missions to form a formation flight schedule. The mission performance reflects the effects of rolled-up wakes, formation heterogeneity, and formation-induced compressibility. The results show that an airline can use formation flight to reduce fuel burn by 5.8% or direct operating …

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Development Of A Method Of Obtaining Fluid Temperature Measurements Using A Laser, Scott L. Thomson, Dr. Dan Maynes Feb 2014

Development Of A Method Of Obtaining Fluid Temperature Measurements Using A Laser, Scott L. Thomson, Dr. Dan Maynes

Journal of Undergraduate Research

Developing a method of measuring fluid temperature using a laser-based system was the goal of this research project. The following paragraphs summarize the research procedure, results, and plans for future development.

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Development Of A One-Piece, Aramid-Polyurethane Bumper System For Automobiles, Brent Zollinger, Dr. Christopher Rotz Feb 2014

Development Of A One-Piece, Aramid-Polyurethane Bumper System For Automobiles, Brent Zollinger, Dr. Christopher Rotz

Journal of Undergraduate Research

The automobile bumper system—consisting primarily of a decorative fascia, structural cross-beam, and energy absorber—is an ideal candidate for redesign using advanced technology. This report examines a concept that integrates the three main components of the bumper system into one by using high-performance materials. A one-piece, aramid-polyurethane composite bumper system that can be manufactured using the SRIM process offers possible weight reductions, cost reductions, and styling versatility, while maintaining manufacturability.

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Fluidic Compression In A Scramjet Engine, Jeff S. Noall, Dr. Russell L. Daines Feb 2014

Fluidic Compression In A Scramjet Engine, Jeff S. Noall, Dr. Russell L. Daines

Journal of Undergraduate Research

A scramjet (supersonic-combustion ramjet) is a theoretical engine which, like a ramjet, converts the velocity of the inlet air into pressure. This “ram” pressure compresses the fluid stream entering the engine prior to fuel injection and combustion. In a ramjet, the incoming air is slowed to subsonic speeds (speeds less than the speed of sound) before combustion occurs. In a scramjet, the air stream remains supersonic throughout the process. This feature gives the scramjet potential in high-speed applications such as hypersonic aircraft and space-transport systems. One of the main problems facing scramjet development is controlling the behavior of the shock …

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Remote Control And Web-Access Of The Mitutoyo Coordinate Measuring Machine, Cun Ling Linda Chu, Dr. C. Greg Jensen Feb 2014

Remote Control And Web-Access Of The Mitutoyo Coordinate Measuring Machine, Cun Ling Linda Chu, Dr. C. Greg Jensen

Journal of Undergraduate Research

The goal of this project was to devise a way to remotely control a Coordinate Measuring Machine (CMM) so students could measure an engineering product wherever they have access to a computer. The project began as a semester assignment for Dr. Jensen’s ME 273 course in the fall of 1998. During the semester a group of students and I researched and developed the basic procedure to accomplish the goal.

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Ground-Effect Flight, Troy Schank, Dr. Paul Eastman Feb 2014

Ground-Effect Flight, Troy Schank, Dr. Paul Eastman

Journal of Undergraduate Research

Ground-effect is a well-known phenomenon that occurs as an aircraft approaches the surface of the earth. Flight in ground-effect changes the characteristics of the airflow around the wing causing both positive and negative effects. Though ground-effect is a well-known phenomenon, the details of lift and drag are less understood. I was able to gain an understanding of the details of ground effect from existing studies and learn from my own experiments in this research.

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Design And Fabrication Of A Water Tunnel For The Byu Mechanical Engineering Department, Lon M. Stevens, Dr. Daniel R. Maynes Feb 2014

Design And Fabrication Of A Water Tunnel For The Byu Mechanical Engineering Department, Lon M. Stevens, Dr. Daniel R. Maynes

Journal of Undergraduate Research

A water tunnel is essential for visualization, validation, and experimental analysis of the fundamental fluid dynamic behavior of flowing liquids. Water tunnels come in a variety of geometric dimensions, which are dependent upon the type of fluid flows that are of interest. It was proposed for this project that a water tunnel be designed to be used for research and instruction in the Mechanical Engineering Department. The test section of the proposed design will be three feet long, eight inches wide, and eight inches high and manufactured from transparent Plexiglas. Water will flow from one side of the tunnel to …

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Systems Integration Of The Goldhelox X-Ray Telescope, Paul F. Eastman, Dr. Thomas J. Utley Jr. Feb 2014

Systems Integration Of The Goldhelox X-Ray Telescope, Paul F. Eastman, Dr. Thomas J. Utley Jr.

Journal of Undergraduate Research

The GoldHelox X-Ray Telescope is an undergraduate project of the Brigham Young University Physics Department in conjunction with the National Aeronautics and Space Administration. It is a fully autonomous robotic telescope and camera system capable of converting x-rays in the range of 171 angstroms into visible light and capturing the source images on 35mm film. This particular wavelength corresponds to the frequency of x-rays emitted by solar flares erupting from the surface of the sun, and by imaging only the x-rays emitted by the flares themselves, the effect will be to strip away much of the rest of the solar …

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Considerations In The Design Of A Prosthetic Foot Using Compliant Design And Analysis Techniques, Kenneth E. Richardson Feb 2014

Considerations In The Design Of A Prosthetic Foot Using Compliant Design And Analysis Techniques, Kenneth E. Richardson

Journal of Undergraduate Research

The modeling of the human body is not an easy task. Designers of artificial organs and prosthetic devices have the unenviable goal of attempting to duplicate (or at least satisfactorily approximate) the motion and function of the greatest and most powerful machine on the face of the earth. Any new tool that could be used in such design would be valuable and useful. Compliant mechanism theory and design is one such tool.

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Development Of Tailsitter Hover Estimation And Control, Jason M. Beach Feb 2014

Development Of Tailsitter Hover Estimation And Control, Jason M. Beach

Theses and Dissertations

UAVs have become an essential tool in many market segments, particularly the military where critical intelligence can be gathered by them. A tailsitter aircraft is a platform whose purpose is to efficiently merge the range and endurance of fixed-wing aircraft with the VTOL capabilities of rotorcraft and is of significant value in applications where launch and recovery area is limited or the use of launch and recovery equipment is not desirable. Developing autopilot software for a tailsitter UAV is unique in that the aircraft must be autonomously controlled over a much wider range of attitudes than conventional UAVs. Assumptions made …

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The Effects Of Winglets At Low Speeds, Brian Johansen Feb 2014

The Effects Of Winglets At Low Speeds, Brian Johansen

Journal of Undergraduate Research

The purpose of an airplane wing is to provide lift by creating a pressure gradient between the top and bottom of the wing. However, this pressure gradient causes some inherent problems at the wing tip. A vortex forms when the high pressure from the bottom side of the wing flows around the wig tip to the top side of the wing. This vortex is detrimental not only to the lift that the wing can produce but to the fuel efficiency of the airplane.

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The Role Of Grain Boundary Misorientation In Intergranular Cracking Of Copper, John W. Bean Feb 2014

The Role Of Grain Boundary Misorientation In Intergranular Cracking Of Copper, John W. Bean

Journal of Undergraduate Research

This report will summarize the efforts and results of the research conducted by John Bean on the role of grain boundary misorientations in intergranular cracking of copper-based metals. This research was conducted during the period of Sept. 1993 toApril1994. I was not able to prove all that I had originally proposed to do because of certain difficulties I will explain below. My research was ended when the equipment I was using was moved at the end of the 1994 winter semester. This report will briefly describe the purpose of my research and the difficulties that I encountered.

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High-Efficiency Thermodynamic Power Cycles For Concentrated Solar Power Systems, Marc T. Dunham, Brian Iverson Feb 2014

High-Efficiency Thermodynamic Power Cycles For Concentrated Solar Power Systems, Marc T. Dunham, Brian Iverson

Faculty Publications

This paper provides a review of high-efficiency thermodynamic cycles and their applicability to concentrating solar power systems, primarily focusing on high-efficiency single and combined cycles. Novel approaches to power generation proposed in the literature are also highlighted. The review is followed by analyses of promising candidates, including regenerated He-Brayton, regenerated CO2-Brayton, CO2 recompression Brayton, steam Rankine, and CO2-ORC combined cycle. Steam Rankine is shown to offer higher thermal efficiencies at temperatures up to about 600 ˚C but requires a change in materials for components above this temperature. Above this temperature, CO2 recompression Brayton cycles are shown to have very high …

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Quadrotors And Accelerometers: State Estimation With An Improved Dynamic Model, Robert C. Leishman, John Macdonald, Randal W. Beard, Timothy W. Mclain Feb 2014

Quadrotors And Accelerometers: State Estimation With An Improved Dynamic Model, Robert C. Leishman, John Macdonald, Randal W. Beard, Timothy W. Mclain

Faculty Publications

The article examines consequences and practical aspects of using an improved dynamic model for quadrotor state estimation with only IMU measurements. The improved model correctly explains the measurements available from the accelerometers on a quadrotor. We give a brief tutorial to explain the difference between accelerometer measurements on a ground vehicle and a quadrotor. We demonstrate several observers based on the improved model to illustrate the estimation improvements available. It is shown that the parameters for this model can be estimated as elements of the state, which makes the model simple to implement and utilize. Finally, we provide hardware results …

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Unity Iv: Fuselage Body Design, Analysis, Testing, And Construction, Alexis J. Pabst, Dr. Paul Eastman Jan 2014

Unity Iv: Fuselage Body Design, Analysis, Testing, And Construction, Alexis J. Pabst, Dr. Paul Eastman

Journal of Undergraduate Research

The Unity IV rocket is a twenty-foot tall rocket with a 16.5-inch diameter. It is a super-sonic, hybrid rocket that uses a solid propellant and liquid oxidizer. The rocket has been designed and built by students from three Utah universities. It is intended to take an instrumentation package super-sonically to an altitude of 130,000 ft and return it safely to earth.

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Comparing Nox Emissions Of Diesel Fuel And Oxygenated Fuels, Timothy M. Allred, Dr. Dale R. Tree Jan 2014

Comparing Nox Emissions Of Diesel Fuel And Oxygenated Fuels, Timothy M. Allred, Dr. Dale R. Tree

Journal of Undergraduate Research

The emissions produced by both passenger and commercial vehicles are a significant contributor to pollution problems that face many cities and areas around the world. One of these pollutants is known as NOx, which refers to the chemical compounds NO2 and NO. These gases are formed when fuel is burned at high temperatures and are an undesirable by-product of the internal combustion engine. Nitrogen dioxide reacts in air to form acid rain as well as contributing to ground-level ozone and smog.

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