Engineering Commons^™

Run-Time Hev Engine-Generator Power-Speed Optimization For Fuel Consumption And Emissions Reduction, Chester Paul Rowe Ii

Doctoral Dissertations and Master's Theses

As fuel economy and emissions standards become more stringent, Plug-in Hybrid Electric Vehicles (PHEV) using series architectures are being increasingly explored. Due to the decoupling of the Internal Combustion Engine (ICE) from the road, the primary control challenge in this architecture is the optimization of an ICE control law. A run-time Genset speed controller is presented for use during the charge-sustaining mode in a Series PHEV to find the optimal operating parameters for a conventional diesel engine coupled to an electric generator in terms of minimized fuel consumption and emissions generation. On board vehicle sensors provide real time data to …

Development, Analysis, And Comparison Of Electromechanical Properties And Electrode Morphology Of Ionic Polymer Metal Composites, Balaji Sivasubramanian

Doctoral Dissertations and Master's Theses

With smart materials and adaptive structures being nudged into mainstream technology progressively, the smart composites are donning a predominant role as indispensable structures. Among these, the Ionic Polymer Metal Composites (IPMC), with their large bending deformation and relaxation characteristics at very low voltages are attractive as transducers in many areas of application. The actuation and sensing properties of IPMC have been sought after for various engineering functions. The paper focuses on manufacturing various types of IPMC. Combining the ionic polymer with platinum electrodes, gold sputter coated electrodes and multi-walled carbon nanotube Bucky paper electrodes to create enhanced IPMCs, comparative analysis …

Fatigue Damage Prognosis Of Internal Delamination In Composite Plates Under Cyclic Compression Loadings Using Affine Arithmetic As Uncertainty Propagation Tool, Audrey J-M Gbaguidi

Doctoral Dissertations and Master's Theses

Structural health monitoring (SHM) has become indispensable for reducing maintenance costs and increasing the in-service capacity of a structure. The increased use of lightweight composite materials in aircraft structures drastically increased the effects of fatigue induced damage on their critical structural components and thus the necessity to predict the remaining life of those components. Damage prognosis, one of the least investigated fields in SHM, uses the current damage state of the system to forecast its future performance by estimating the expected loading environments. A successful damage prediction model requires the integration of technologies in areas like measurements, materials science, mechanics …

Development Of An Exteroceptive Sensor Suite On Unmanned Surface Vessels For Real-Time Classification Of Navigational Markers, Christopher Lloyd Kennedy

Doctoral Dissertations and Master's Theses

This thesis presents the development of an exteroceptive sensor suite for real-time detection and classification of navigational markers on Unmanned Surface Vessels. Three sensors were used to complete this task: a 3D LIDAR and two visible light cameras. First, all LIDAR points were transformed from the sensor’s reference frame to the local frame using a Kalman filter to estimate instantaneous vehicle pose. Next, objects were chosen from the LIDAR data to be classified using either Multivariate Gaussian or Parzen Window Classifiers. Both produce 96% accuracy or better, however, multivariate Gaussian ran considerably faster than the Parzen and was simpler to …

Design And Dynamic Analysis Of A Variable-Sweep, Variable-Span Morphing Uav, Nirmit Prabhakar

Doctoral Dissertations and Master's Theses

Morphing wings have the potential to optimize UAV performance for a variety of flight conditions and maneuvers. The ability to vary both the wing sweep and span can enable maximum performance for a diverse range of flight regimes. For example, low-speed missions can be optimized using a wing with high aspect ratio and no wing sweep whereas high-speed missions are optimized with low aspect ratio wings and large wing sweep. Different static morphing wing configurations clearly result in varying aerodynamics and, as a result, varying dynamic modes. Another important consideration, however, is the transient dynamics that occur when transitioning between …

Characterization Of Electron Number Density Of Rocket Exhaust Plumes Through Microwave Transmissions, Jorge Torres

Doctoral Dissertations and Master's Theses

Charged rocket plumes generally exceed the length of their source vehicles, and offer lightning a favorable path to ground. Rocket plumes enhance the induced transient currents in flight electronics, and increase the risk of vehicle failure. The affinity of lightning to the plume can be associated with the plume's electrical properties, which are coupled to plasma characteristics including the electron number density. However, the electron number density of rocket plumes is not well-known. In this study, the electron number density is characterized through data from static rocket firings. A model of the plume in finite difference time domain (FDTD) simulations …

Vision-Aided Navigation For Gps-Denied Environments Using Landmark Feature Identification, Tennyson Samuel John

Doctoral Dissertations and Master's Theses

In recent years, unmanned autonomous vehicles have been used in diverse applications because of their multifaceted capabilities. In most cases, the navigation systems for these vehicles are dependent on Global Positioning System (GPS) technology. Many applications of interest, however, entail operations in environments in which GPS is intermittent or completely denied. These applications include operations in complex urban or indoor environments as well as missions in adversarial environments where GPS might be denied using jamming technology.

This thesis investigate the development of vision-aided navigation algorithms that utilize processed images from a monocular camera as an alternative to GPS. The vision-aided …

Experimental Validation Of A New Distributed Cooperative Control Algorithm For Multi-Agent Systems With Switching Communication Topologies And Time-Delays, Junzhen Shao

Doctoral Dissertations and Master's Theses

In this thesis, we present practical experimental results to demonstrate a control law for consensus of multiagent systems with switching topologies and time delays. The nonlinear control law utilizes discontinuous cooperative control gains and uses contraction mapping to achieve consensus of multiagent systems. The testing platform we used consists of a number of mobile robots and software simulations both in Matlab and Microsoft Studio C++. We present the effectiveness of the control law design by Aria mobile robots with applications in distributed cooperative formation control. Computer simulations and hardware experiments presented include point consensus control and formation control, both with …

Human Behavior During Spaceflight: Evidence From An Analog Environment, Kenny Mikael Arnaldi

Doctoral Dissertations and Master's Theses

Spaceflight offers a multitude of stressors to humans living and working in space, originating from the external space environment and the life-support system. Future space participants may be ordinary people with different medical and psychosocial backgrounds who may not receive the intense spaceflight preparation of astronauts. Consequently, during a mission, a space participant’s mood and behavior could differ from a trained astronaut. This study was an exploratory research project that used an artificial habitat to replicate an orbital environment and the activities performed by humans in space. The study evaluated whether the type of environment affects mood and temperament. Two …

Enhancement Techniques Of Boiling Heat Transfer, Basim Qasim Ali Al-Sukaini

Doctoral Dissertations and Master's Theses

The aim of this study is to investigate pool boiling performance of water under atmospheric pressure by two techniques. The first method is by adding small amounts of surfactants, and the second way is by using structured surfaces.

The first technique is investigated experimentally with environmentally friendly surfactants. The surfactants chosen for the study are an ionic sodium lauryl sulfate (SLS), nonionic ECOSURF™ EH-14, and nonionic ECOSURF™ SA-9. It is observed that adding a small amount of surfactant alters the water boiling phenomenon significantly. Boiling curves for different concentrations are shifted to the left. The wall temperature drops greatly with …

Development Of A System Architecture For Unmanned Systems Across Multiple Domains, Charles Randall Breingan Jr.

Doctoral Dissertations and Master's Theses

In the unmanned systems industry, there is no common standard for systems components, connections and relations. Such a standard is never likely to exist. Needless to say, a system needs to have the components that are required for the application, however, it is possible to abstract the common functionality out of an individual implementation. This thesis presents a universal unmanned systems architecture that collects all of the common features of an unmanned system and presents them as a set of packages and libraries that can be used in any domain of unmanned system operation. The research and design of the …

Situational Leadership Styles In United States Air Force Air Traffic Control Towers, William D. Melton, Chad L. Depperschmidt, Timm J. Bliss

International Journal of Aviation, Aeronautics, and Aerospace

Leadership in air traffic control facilities is critical to the safe, orderly, and efficient flow of air traffic. The purpose of this qualitative study was to determine the preferred leadership style for United States Air Force air traffic control tower watch supervisors. A panel of 10 functional experts completed a 25 question scenario-based survey to establish a baseline for this study’s four research questions. A purposeful sample of eight control tower chief controllers representing the eight United States Air Force major commands were interviewed and their responses were compared to the mean of the experts panel. The data from the …

Achieving Global Range In Future Subsonic And Supersonic Airplanes, Nihad E. Daidzic Ph.D., Sc.D.

International Journal of Aviation, Aeronautics, and Aerospace

No commercial airplane in service today is able to fly half great-circle distances over the globe and achieve the non-stop or the global range to any antipodal location on Earth. A subsonic jetliner has the optimum cruising speed at Mach numbers approaching the drag divergence Mach number while still preserving relatively high aerodynamic efficiency. Various fuel-flow laws were used to investigate the cruise performance of subsonic and supersonic aircraft. The effect of wind and aircraft weight and how it affects the optimal cruising airspeed was investigated. Of all different operational cruising techniques, the cruise-climb at high Mach numbers is the …

Reliability Of Eyewitness Reports To A Major Aviation Accident, Dave English, Michael Kuzel

International Journal of Aviation, Aeronautics, and Aerospace

There is a paucity of studies on the reliability of eyewitness reports to aviation crashes. We examine witness statements to a widely observed major airline accident to determine if reported accident investigator distrust of details in eyewitness reports is supported by empirical evidence. The extensive archival witness record (N > 300) of a wide-body airliner crash in clear daylight conditions is subjected to statistical analysis to test eyewitness reliability. Even with over 200 witnesses within a three square kilometre (1.6 square mile) area answering a binary observation question, the variance is sometimes high enough to preclude forming statistically significant conclusions …

Memphis Belle, Hot Stuff, Gen Andrews & The Quest To Be First To Complete 25, William Waldock

ERAU Prescott Aviation History Program

Most people know of Memphis Belle, the first heavy bomber to complete 25 missions. But did you know that honor really belongs to a B-24 named Hot Stuff? Learn the true story of this aircraft and its sad ending from ERAU accident investigator Bill Waldock.

Inverse Volume-Of-Fluid Meshless Method For Efficient Non-Destructive Thermographic Evaluation, Hussein Awad Kurdi Saad

Doctoral Dissertations and Master's Theses

A novel computational tool based in the Localized Radial-basis Function (RBF) Collocation (LRC) Meshless method coupled with a Volume-of-Fluid (VoF) scheme capable of accurately and efficiently solving transient multi-dimensional heat conduction problems in composite and heterogeneous media is formulated and implemented. While the LRC Meshless method lends its inherent advantages of spectral convergence and ease of automation, the VoF scheme allows to effectively and efficiently simulate the location, size, and shape of cavities, voids, inclusions, defects, or de-attachments in the conducting media without the need to regenerate point distributions, boundaries, or interpolation matrices. To this end, the Inverse Geometric problem …

The History Of Space Debris, Loretta Hall

Space Traffic Management Conference

This paper examines what space debris consists of and where it came from. In 1958, astronomer Clyde Tombaugh published the results of his research into the existence of natural debris near the Earth, concluding that no such debris existed. During the ensuing fifty-five years, man-made debris has been accumulating to the point that it threatens launches, active satellites, and the International Space Station. NASA reported that as of 2013, more than 21,000 pieces the size of a softball or larger were being tracked, as were about 500,000 pieces at least the size of a marble and “many millions” of pieces …

An Integrated Approach To Orbital Debris Research And Management, Marshall H. Kaplan

Space Traffic Management Conference

A viable space traffic management program faces a great barrier caused by the ever-increasing number and variety of orbiting objects ranging in size from a few microns to several meters. Although several international agreements to limit the growth rate of orbital debris are in place, the risk of damage and destruction to active satellites is continually rising. The urgency of this situation was highlighted by the 2007 Chinese ASAT test and the collision of Iridium and Cosmos satellites in 2009. Although many debris removal techniques have been posited none have been implemented. Unless a space debris reduction program is undertaken …

Weather Research Requirements To Improve Space Launch From Cape Canaveral Air Force Station And Nasa Kennedy Space Center, William P. Roeder, Lisa L. Huddleston, William H. Bauman Iii, Kelly B. Doser

Space Traffic Management Conference

Weather has a large affect on operations at Cape Canaveral Air Force Station (CCAFS) and NASA Kennedy Space Center (KSC). Weather is the leading source of scrubs and delays to space launch from CCAFS/KSC. Weather has an even larger impact on ground processing as space launch vehicles and payloads are prepared in the months before space launch. Many of those operations are very sensitive to weather. In addition, the weather in Florida is notoriously difficult to predict, especially during the summer when rapid deep convection can occur in minutes. Finally, the weather can be extremely subtle in this area during …

Where Is Space? And Why Does That Matter?, Bhavya Lal, Emily Nightingale

Space Traffic Management Conference

Despite decades of debate on the topic, there is no consensus on what, precisely, constitutes the boundary between airspace and outer space. The topic is mired in legal and political conundrums, and the easy solution to-date has been to not agree on a definition of space. Lack of a definition, some experts claim, has not limited space-based activities, and therefore is not a hurdle that must be overcome. There are increasing calls however in light of increasing (and expectations of increasing) space traffic, both orbital and sub-orbital. This paper summarizes the proposed delimitation of space, the current debate on whether …

Challenges And Opportunities Related To Landing The Dream Chaser® Commercial Reusable Space Vehicle At A Public-Use Airport, Brian Gulliver, Cassie Lee, Frank Taylor, Ken Ibold, Christopher Allison

Space Traffic Management Conference

Sierra Nevada Corporation’s (SNC) Space Systems is developing the Dream Chaser^® reusable space vehicle for NASA’s Commercial Crew Program. The Dream Chaser is a lifting body vehicle that lands on a runway similar to the Space Shuttle. Unlike the Shuttle, the Dream Chaser does not require any unique landing aids or specialized equipment as it uses all non-toxic propellants and industry standard subsystems. This allows for immediate access to crew and cargo at wheels-stop. Requiring only 8,000 ft/2,400 m of runway for landing, the Dream Chaser is compatible with numerous public runways. There are, however, unique and complex challenges …

Faa Letter In Response To White House Letter Regarding Faa Changes To Air Traffic Control Specialist Hiring Process, Tim Brady, Gregory Mcguirk

Publications

On July 18, 2014, you submitted a letter to President Obama regarding the Federal Aviation Administration's (FAA) recent changes to the Air Traffic Control Specialist (ATCS) hiring process. You expressed concern with the FAA's decision to implement a single all sources hiring strategy and, as a result, you feel that it has disadvantaged graduates who successfully completed the Air Traffic Collegiate Training Initiative (AT-CTI) program, such as xxx. You also expressed concern with the implementation of the Biographical Assessment. Your letter was forwarded by the White House to our agency to address your concerns.

Aerodynamic Optimization Of Box Wing – A Case Study, Adeel Khalid, Parth Kumar

International Journal of Aviation, Aeronautics, and Aerospace

The optimization of a possible medium range box wing commercial airliner is presented in three stages. Preliminary research is used to determine various parameters for a potential box wing model, and a baseline model is designed in Autodesk Inventor, based upon the cantilever Airbus A330-200, an aircraft of a similar role. The Computational Fluid Dynamics (CFD) software used in this project is Dassault Systèmes SolidWorks, which is validated through comparing the NACA 0009 airfoil lift and drag polars with published results. The first stage of optimization is performed on the airfoil shape, with 8 different designs being tested against the …

A Cfd Investigation Of The Hydrodynamic Characteristics Of Fluid Flow Through An Impeller And Multi-Objective Design Optimization Of A Centrifugal Pump, Mohammed Khammat Sagban

Doctoral Dissertations and Master's Theses

In this thesis, the first part is conducting an investigation of the hydrodynamic characteristics (pressure and velocity) of fluid flow (water) through an impeller of a centrifugal pump. To illustrate a one-dimensional model is used to identify an impeller of a GDM 10 x 12 HD centrifugal pump using Vista CPD design and BladeGen tool. A three-dimensional model is then built with a commercial software package ANSYS Blade Modeler. The structured mesh of the impeller blade is obtained by using TurboGrid system. The volute of the centrifugal pump is built in ANSYS geometry, and an unstructured mesh is accomplished by …

A Continuous/Discontinuous Fe Method For The 3d Incompressible Flow Equations, Nikolaos Kyriazis

Doctoral Dissertations and Master's Theses

A projection scheme for the numerical solution of the incompressible Navier-Strokes equation is presented. Finite element discontinuous Galerkin (dG) discretization for the velocity in the momentum equations is employed. The incompressibility constraint is enforced by numerically solving the Poisson equation for pressure using a continuous Galerkin (cG) discretization. The main advantage of the method is that is does not require the velocity and pressure approximation spaces to satisfy the usual inf-sup condition, thus equal order finite element approximations for both velocity and pressure can be used. Furthermore, by using cG discretization for the Poisson equation, no auxiliary equations are needed …

Modeling Hydrodynamic Stability Of Incline-Liquid Airblast Nozzle For Gas Turbine Combustion, Kevin Matiko

Doctoral Dissertations and Master's Theses

Fuel is a major cost item for civil transport airplanes. Minimizing fuel consumption of these crafts is a stream of economic opportunity and a stage for innovation, competition and exploration. Regardless of the fuel type, bio or crude oil based, the civil transport stakeholders would like to minimize fuel consumption of their airplanes. The mixing of fuel and air is a critical process for optimum combustion in gas turbine engines due to its high influence on the downstream combustion process. The need for minimizing fuel consumption coupled with the requirement for combustion systems to perform well at all flight conditions …

To Study The Effect Of Catalyst On The Physical Parameters Of Carbon Spheres, Tejas Shailesh Mehta

Doctoral Dissertations and Master's Theses

The discovery of fullerenes has opened up modern studies in carbon materials. Carbon nanoparticles have a large surface area and demonstrate good conductivity. Their unique properties has gained attention in many areas such as water filtration, hydrogen storage and battery electrodes. In this research, carbon spheres with high specific area and uniformity were grown using the Chemical Vapor Deposition (CVD) process with silicon substrates, ethylene (C2H4) as a carbon precursor and argon as the inert gas. We observe that the morphology of carbon spheres largely depend on the experimental conditions, including CVD time duration, temperature, catalyst and flow of gases. …

Exploration Of A Computational Fluid Dynamics Integrated Design Methodology For Potential Application To A Wind Turbine Blade, Gaurav Kapoor

Doctoral Dissertations and Master's Theses

The main purpose of this thesis is to conduct a parametric sensitivity study on the blade design of AOC 15/50 wind turbine based on a CFD approach and optimize the blade design for maximizing the power output. The ANSYS® Fluent® flow solver using the k-ω SST turbulence model was validated by simulating the flow over two dimensional airfoils comprising the AOC 15/50 wind turbine blade. The CFD results have shown a considerable agreement with the experimental data for the airfoils. Parametric correlation study and sensitivity analysis were conducted by performing actual flow simulations over the turbine blade using ANSYS® Fluent®. …

Improving Airplane Touchdown Control By Utilizing The Adverse Elevator Effect, Nihad E. Daidzic Ph.D., Sc.D.

International Journal of Aviation, Aeronautics, and Aerospace

The main objective of this original research article is to understand the short-term dynamic behavior of the transport-category airplane during landing flare elevator control application. Increasing the pitch angle to arrest the sink rate, the elevator will have to produce negative lift to rotate the airplane’s nose upward. This has an immediate adverse effect of initially accelerating airplane downward. A mathematical model of landing flare based on the flat-Earth longitudinal dynamics of rigid airplane was developed which is realistic only on very short time-scales as pitch stiffness and damping were neglected. Pilot control scenarios using impulse and step elevator pull-up …

Designing Case Study Research For Pedagogical Application And Scholarly Outcomes, Jacqueline R. Luedtke, Juan R. Merkt, Brent D. Bowen

Aeronautical Science - Prescott

The purpose of this paper is to present the pedagogical/andragogical model of case study research in capstone courses in collegiate aviation programs. As higher education continues to advance in examining new or different ways to engage students, case study research in a capstone course affords seniors the opportunity to engage in learning how to plan, investigate, write a case study research report and present their findings on a topic of interest.