Mechanical Engineering Commons^™

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 …

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 …

Femtosecond And Nanosecond Dual-Laser Optical Emission Spectroscopy Of Gas Mixtures, Cheng Hsiang Lin, Zhi Liang, Jun Zhou, Hai-Lung Tsai

Mechanical and Aerospace Engineering Faculty Research & Creative Works

A Method Employing an Integrated Femtosecond (Fs) and Nanosecond (Ns) Dual-Laser System Was Developed to Generate Plasma with Desired Radical Species from Gas Mixtures Via a Fs Laser Pulse and Then to Excite Selected Radical Species to Higher Electronic States using a Wavelength-Tunable Ns Laser Pulse. an Optical Spectrometer Was Used to Measure the Emission Spectra and Identify the Transition from the Excited Electronic State to the Ground State. the Proposed Technique Has Been Demonstrated for an N2-CO2 Mixture with Various Time Delays between the Two Fs and Ns Pulses. the Results Have Indicated that the Population of Selected Radical …

Computational Optimization Methods For Modeling The Effect Of Muscle Forces On Bone Strength Adaptation, Catherine Siena Florio

Dissertations

An improved understanding of the mechanical influences that alter the strength of a bone can aid in the refinement of the wide array of currently available techniques to counteract the losses of bone strength that occur due to age or disuse both on Earth and in Space. To address this need, computational modeling methods to quantitatively analyze and compare the effects of mechanical factors on the strength of a targeted bone within a multibone, multimuscle system are developed and implemented in this work. Through a more detailed representation of the system in which the bone acts and the creation of …

Influence Of Lateral Boundaries In Tapped Densification Of Granular Materials, Nathaniel Ching

Theses

Granular systems are widely present in the world. Soil, pharmaceutical pills, and silos filled with grain all are examples of granular systems. Experiments have long established an empirical understanding of granular systems, but an analytical understanding has been much more difficult to establish. One of the behaviors of a granular system that is well documented but poorly understood is the change in density the system undergoes when excited, also known as the densification process.

This thesis investigates the densification process of a tapped granular system using Discrete Element Model (DEM) simulations. Contact interactions in the simulations obey a well-established inelastic …

Using “Expert Employees” To Identify Duties And Tasks For Cadd Technicians In North Central Idaho: Lessons Learned From A Modified Dacum Process, Raymond A. Dixon Ph.D., Linda S. Stricklin Ph.D.

Online Journal for Workforce Education and Development

Objective: We conducted a job analysis to identify the competency profile of an entry level CADD technician in North central Idaho. Background: In 2011, the Clearwater Economic Development Association and NIMA collaborated with Lewis-Clark State College and the University of Idaho in a project to strengthen the capacity of Career and Technology Education (CTE) teachers to teach computer aided drafting and designing (CADD). An application to the National Science Foundation, Advanced Technology Education (NSF ATE) program was made and funding began July of 2011. Method: A modified DACUM was used. A total of seven expert workers from …

Sr3<−3xNa3xSi3O9−1.5x (X = 0.45) As A Superior Solid Oxide-Ion Electrolyte For Intermediate Temperature-Solid Oxide Fuel Cells, Tao Wei, Preetam Singh, Yunhui Gong, John B. Goodenough, Yunhui Huang, Kevin Huang

Faculty Publications

We here report that a newly discovered superior oxide-ion conductor Sr_3−3xNa_3xSi₃O_9−1.5x (x = 0.45) (SNS) demonstrates full potential to be a practical solid electrolyte for intermediate temperature-solid oxide fuel cells (IT-SOFCs). It exhibits the highest oxide-ion conductivity with the lowest activation energy among all the chemically stable solid oxide-ion conductors reported. The ionic conductivity is stable over a broad range of partial pressures of oxygen (10⁻³⁰ to 1 atm) for an extended period of time. A SOFC based on a 294 μm thick SNS-electrolyte produces peak power densities …

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.

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.

A New Stereology, Ryan J. Larsen, Dr. Brent L. Adams

Journal of Undergraduate Research

Much research in recent years has focused on producing polycrystalline materials with high numbers of special grain boundaries. Special grain boundaries are defined as boundaries with desirable properties, such as resistance to corrosion, cracking, or precipitation. Most researchers describe grain boundary geometry only with the three parameters of misorientation between adjacent crystal lattices. Although misorientation data have been successfully linked to some properties, knowledge of misorientation alone is insufficient to predict grain boundary energy, and can thus provide only a first-order approximation of a boundary’s properties.

Developing Mechanisms As Liga Microstructures, Jordan E. Brough, Dr. Larry Howell

Journal of Undergraduate Research

Microelectromechanical Systems (MEMS) is a rapidly developing field which uses technology similar to that used to carve out the millions of tiny channels found in today’s computer processors. MEMS, however, uses this technology to make mechanical structures and mechanisms instead of electrical pathways. My effort over the past eight months has been to research the developing LIGA MEMS design (an electromolding process), fabricate a test structure via the LIGA technology, and in the process establish a working relationship between Sandia National Laboratories California (a leader in MEMS) and BYU’s microengineering team.

Use Of Linear Analysis Of Microstructures In Defining Performance Closures For Highly Constrained Mechanical Design, Mark Lyon, Dr. Brent L. Adams

Journal of Undergraduate Research

Using methods described by Adams1, the design of a compliant beam was modeled in a multidimensional Fourier design space. A compliant beam is one that achieves motion through bending. The motivation for the problem was a bicycle derailleur. A compliant beam could replace the entire rear derailleur if a large amount of flexibility could be obtained and yet have a relatively strong force when displaced to return the beam to its original position. The compliant derailleur would be simpler and cheaper than current derailleur designs. In general, metals are too stiff and plastics are too weak for this application. The …

A Compliant Orthoplanar Piezoelectric Actuator, Aaron Shelley, Dr. Larry Howell

Journal of Undergraduate Research

This research focused on developing a new actuator/motor by integrating two previously unrelated technologies. In the past, piezoelectric crystals have been used primarily to measure acceleration in the engineering field, because of their unique nature of generating electricity when changes in their position occur. Modern researchers now use piezoelectric crystals in the opposite way, in that they put electricity through the crystals, causing them to expand or contract. The ability to cause the crystals to expand/contract merely by having a voltage difference across the crystal represents a whole new method of creating actuators/motors.

Impact Of Residential Mechanical Ventilation On Energy Cost And Humidity Control, Florida Solar Energy Center, Eric Martin

FSEC Energy Research Center®

The DOE Building America program has been conducting research leading to cost effective high performance homes since the early 1990's. Optimizing whole house mechanical ventilation as part of the program's systems engineered approach to constructing housing has been an important subject of the program's research. Ventilation in residential buildings is one component of an effective, comprehensive strategy for creation and maintenance of a comfortable and healthy indoor air environment. The study described in this white paper is based on building energy modeling with an important focus on the indoor humidity impacts of ventilation. The modeling tools used were EnergyPlus version …

Design Of Equipment To Test Compliant Centrifugal Clutches, Nathan B. Crane, Dr. Larry L. Howell

Journal of Undergraduate Research

A compliant mechanism is a mechanism in which some or all motion comes from deflection of its members. Several years ago, a one piece centrifugal clutch based on a compliant mechanism was developed and implemented in several products. It offers many cost and assembly advantages over traditional clutch designs containing at least five components.

The Developing Length Of Electro-Osmotic Flow, Joseph Scott Tenny, Dr. Daniel Maynes

Journal of Undergraduate Research

Recent advancements in technology have created the need for increased understanding of fluid flow in microtubes with a diameter of a 100μm or less. These types of flows can occur in many practical applications, one of which is a concept proposed for DNA analysis called “lab on a chip.” At this physical scale, the pressures required to drive the flow of the fluid are often too large for any type of potential application. An alternative approach to driving the fluid through a microtube is to use electro-osmosis. This type of flow uses an applied voltage potential to drive the fluid …

Optimization Of Wind Turbine Airfoils/Blades And Wind Farm Layouts, Xiaomin Chen

All Theses and Dissertations (ETDs)

Shape optimization is widely used in the design of wind turbine blades. In this dissertation, a numerical optimization method called Genetic Algorithm (GA) is applied to address the shape optimization of wind turbine airfoils and blades. In recent years, the airfoil sections with blunt trailing edge (called flatback airfoils) have been proposed for the inboard regions of large wind-turbine blades because they provide several structural and aerodynamic performance advantages. The FX, DU and NACA 64 series airfoils are thick airfoils widely used for wind turbine blade application. They have several advantages in meeting the intrinsic requirements for wind turbines in …

Nasa Human Exploration Rover Challenge, Estelle Fortes, Aaron Taylor, Caitlin Talerico, Jessica Chow, Jessica Turcios, Johnnie Perry, Joshua Beck, Juana Cecilia Martin-Gonzalez, Lisa Ferguson, Michaela Branscomb, Mo Sabliny, Raeann Vansickle, Sarah Pearson, Sierra Dryer, Zach Henney, Brenda Haven

Aviation / Aeronautics / Aerospace International Research Conference

NASA's Great Moonbuggy Race, held annually in at the Marshall Space Flight Center in Huntsville, Alabama, is an engineering design challenge that asks teams of student engineers to design a human-­‐powered vehicle capable of traversing a simulated lunar surface. However, there is an interesCng sCpulaCon in the design of the moonbuggy: it must be able to be transported in a 4x4x4 foot cube, echoing the design constraint faced by the engineers who built the Lunar Roving Vehicles used by the astronauts of the later Apollo missions. The vehicle in this proposal, Ocelot, designed by the Society of Women Engineers at …

Applications Of Long-Wave Thermal Infrared Imagers On Unmanned Aerial Systems For First Responders, Nick Harris, Lorenzo Coykendall

Aviation / Aeronautics / Aerospace International Research Conference

The Embry-Riddle Prescott UAS Team will design, build, and test three Unmanned Aerial Systems (UAS) for competing in the student UAS Competition June 18 - 22 in Patuxent River, MD hosted by the Association for Unmanned Vehicle Systems International (AUVSI).

The team will design and build these unmanned aircraft to carry a five-pound payload, sustain flight for at least forty minutes, and be hand-launchable and rugged; they will be constructed from composite materials and will be fully autonomous through the use of open-source autopilots.

The Effects Of Tool And Temperature Parameters On Grain Growth In Friction Stir Welded 7050 And 7475 Aluminum, Kevin Allen Schwendiman, Dr. Tracy Nelson, Dr. Carl Sorenson

Journal of Undergraduate Research

The Welding Institute (TWI) in Cambridge, England invented friction stir welding (FSW) late in 1991. TWI applied in December of that year for worldwide patent protection. The friction stir welding process is simple, energy-efficient and inexpensive relative to other welding methods. FSW can be implemented to make high quality welds with the most versatility – meaning the process can be used in almost all positions. Tensile, fatigue and bending tests have demonstrated that the properties of friction stir welded materials are superior to those made by other welding methods such as fusion or arc welding.

Low Reynolds Number Aerodynamics For Micro Air-Vehicles (Mav), Paul Nelson, Chad Lebaron, Bart Frischknecht, Kristopher Danielson, Jerry Bowman

Journal of Undergraduate Research

Very little aerodynamic data exists for Reynolds numbers less than 100,000. It is common for there to be a large discrepancy between numerically predicted and experimental airfoil performance, especially at very low Reynolds numbers. In this research, a low Reynolds number airfoil was developed based on aerodynamic measurements.

An Examination Of The Usefulness Of Lapping For Reducing Tip Leakage In Scroll Compressors, Jared W. Jensen, Paul Eastman, Jason Hugenroth

Journal of Undergraduate Research

Scroll compressors are unique in that the working fluid (in most cases, Freon or Puron™) is continuously compressed in an involute wrap. The geometry of the two scrolls is such that the gas is compressed towards the center in progressively smaller chambers as one scroll orbits the other. Before the gas is discharged, the involute returns to an intake state allowing the compressor to compress several “pockets” of refrigerant at the same time.

Computer Simulation Of Microstructures Based On Two-Point Correlation Functions, Benjamin L. Hansen, Dr. Brent Adams

Journal of Undergraduate Research

A great amount of variance exists in the properties of any material. The ability to accurately predict these properties allows for designers to find the “best” material in highly constrained design situations. Many properties, such as elasticity and conductivity, are relatively insensitive to grain boundary interfaces and dislocations, and are thus accurately predicted by simple averaging techniques with a first-order description of the microstructure. However, many properties that effect lifetime to failure such as plastic yielding, intergranular stress corrosion cracking, and embrittlement are sensitive to dislocations and grain boundary interfaces. Therefore, second-order descriptions of the microstructures are needed to estimate …

Use Of A Gradient-Based Search Method To Reconstruct The Temperature Profile Along An Optical Fiber Thermometer, David G. Barker, Dr. Matthew R. Jones

Journal of Undergraduate Research

Advances in the area of Optical Fiber Thermometry (OFT) are leading to more accurate temperature measurements in high-temperature environments. A typical OFT application is when the tip of an optical fiber is inserted into an environment where the temperature is to be measured. The other end of the fiber is attached to an optical system where light from the fiber is measured (see Figure 1). From the light emission measurements, the temperature at the heated tip of the fiber can be inferred.¹

Dynamical Heterogeneity In Periodically Deformed Polymer Glasses, Nikolai V. Priezjev

Mechanical and Materials Engineering Faculty Publications

The dynamics of structural relaxation in a model polymer glass subject to spatially homogeneous, time-periodic shear deformation is investigated using molecular dynamics simulations. We study a coarse-grained bead-spring model of short polymer chains below the glass transition temperature. It is found that at small strain amplitudes, the segmental dynamics is nearly reversible over about 104 cycles, while at strain amplitudes above a few percent, polymer chains become fully relaxed after a hundred cycles. At the critical strain amplitude, the transition from slow to fast relaxation dynamics is associated with the largest number of dynamically correlated monomers as indicated by the …

Quantification Of Transhumeral Prosthetic Socket Residual Limb Interface Movement Using Motion Capture And A Slip Detection Sensor, Matthew Wernke

USF Tampa Graduate Theses and Dissertations

Current literature focusing on the prosthetic socket is limited by measurement techniques and modeling assumptions, leading to a limited understanding of the forces and motions occurring between the residual limb and prosthesis and how they can be used to influence socket design and fitting. Prosthetic socket fitting and prescription would benefit from an elegant method for comparing socket designs. This dissertation focuses on the development and implementation of a 3D motion capture model and a Slip Detection Sensor to quantify rotations and translations at the prosthetic socket-residual limb interface. The 3D motion capture model defines the residual limb bone position …

Expressing The Joint Moments Of Drop Jumps And Sidestep Cutting In Different Reference Frames – Does It Matter?, Eirik Kristianslunda, Tron Krosshauga, Kam-Ming Mok, Scott Mclean, Antonie J. Van Den Bogert

Mechanical Engineering Faculty Publications

Joint moments help us understand joint loading and muscle function during movement. However, the interpretation depends on the choice of reference frame, but the different reference frames have not been compared in dynamic, high-impact sporting movements. We have compared the magnitude and the resulting ranking of hip and knee joint moments expressed in the laboratory coordinate system, the local system of the distal segment and projected or decomposed to the Joint Coordinate System (JCS) axes. Hip and knee joint moments of drop jumps and sidestep cutting in 70 elite female handball players were calculated based on recordings from an eight-camera …

Rapid Space Trajectory Generation Using A Fourier Series Shape-Based Approach, Ehsan Taheri

Dissertations, Master's Theses and Master's Reports - Open

With the insatiable curiosity of human beings to explore the universe and our solar system, it is essential to benefit from larger propulsion capabilities to execute efficient transfers and carry more scientific equipment. In the field of space trajectory optimization the fundamental advances in using low-thrust propulsion and exploiting the multi-body dynamics has played pivotal role in designing efficient space mission trajectories. The former provides larger cumulative momentum change in comparison with the conventional chemical propulsion whereas the latter results in almost ballistic trajectories with negligible amount of propellant. However, the problem of space trajectory design translates into an optimal …

Water Transport Through Porous Media And In Flow Channels Of Proton Exchange Membrane Fuel Cell, Mehdi Mortazavi

Dissertations, Master's Theses and Master's Reports - Open

Proton exchange membrane (PEM) fuel cell has been known as a promising power source for different applications such as automotive, residential and stationary. During the operation of a PEM fuel cell, hydrogen is oxidized in anode and oxygen is reduced in the cathode to produce the intended power. Water and heat are inevitable byproducts of these reactions. The water produced in the cathode should be properly removed from inside the cell. Otherwise, it may block the path of reactants passing through the gas channels and/or gas diffusion layer (GDL). This deteriorates the performance of the cell and eventually can cease …

Hybrid Tio2 Solar Cells Produced From Aerosolized Nanoparticles Of Water-Soluble Polythiophene Electron Donor Layer, Marshall L. Sweet, Joshua G. Clarke, Dmitry Pestov, Gary C. Tepper, James T. Mcleskey Jr.

Mechanical and Nuclear Engineering Publications

Hybrid solar cells (HSCs) with water soluble polythiophene sodium poly[2-(3-thienyl)-ethyloxy-4-butylsulfonate] (PTEBS) thin films produced using electrospray deposition (ESD) were fabricated, tested, and modeled and compared to devices produced using conventional spin coating. A single device structure of FTO/TiO2/PTEBS/Au was used to study the effects of ESD of the PTEBS layer on device performance. ESD was found to increase the short circuit current density (J_sc) by a factor of 2 while decreasing the open circuit voltage (V_oc) by half compared to spin coated PTEBS films. Comparable efficiencies of 0.009% were achieved from both device construction types. Current-voltage …