Engineering Commons^™

Integrity Determination For Image Rendering Vision Navigation, Sean M. Calhoun

Theses and Dissertations

This research addresses the lack of quantitative integrity approaches for vision navigation, relying on the use of image or image rendering techniques. The ability to provide quantifiable integrity is a critical aspect for utilization of vision systems as a viable means of precision navigation. This research describes the development of two unique approaches for determining uncertainty and integrity for a vision based, precision, relative navigation system, and is based on the concept of using a single camera vision system, such as an electro-optical (EO) or infrared imaging (IR) sensor, to monitor for unacceptably large and potentially unsafe relative navigation errors. …

Unmanned Aerial Vehicle (Uav) Operators’ Workload Reduction: The Effect Of 3d Audio On Operators’ Workload And Performance During Multi-Aircraft Control, Sungbin Kim

Theses and Dissertations

The importance and number of Unmanned Aerial Vehicle (UAV) operations are rapidly growing in both military and civilian applications. This growth has produced significant manpower issues, producing a desire that multiple aircraft are controlled by a single operator as opposed to the current model where one aircraft may require multiple operators. A potential issue is the need for an operator to monitor radio traffic for the call signs of multi-aircraft. An investigation of the use of 3D sound was undertaken to investigate whether an automatic parser, which preselected the spatial location of relevant versus irrelevant call signs, could aid UAV …

Analysis Of Inpatient Hospital Staff Mental Workload By Means Of Discrete-Event Simulation, Erich W. Maxheimer

Theses and Dissertations

Many process improvement tools have been applied to the healthcare industry to improve safety and efficiency. However, nearly all of these tools have neglected to explicitly quantify mental workload of healthcare providers despite the consensus that it is related to human performance. This research uses the Improved Performance Research Integration Tool (IMPRINT), a discrete-event simulation (DES), to quantify mental workload. Specifically, this research examines staff members in an inpatient unit at the Wright-Patterson Medical Center to detect workload differences between staff, identify trends which lead to high workload demands, evaluate the influence of patient load on mental workload, and test …

Characterizing Emissions From Open Burning Of Military Food Waste And Packaging From Forward Operating Bases, Thomas Dominguez

Theses and Dissertations

Emissions were characterized and compared from the open burning of four compositions of Meals, Ready-To-Eat (MRE) and four types of MRE fiberboard packaging in response to inhalation concerns at military forward operating bases. Measurements of particulate matter (PM2.5, PM10) showed that MREs account for 70-90 percent of PM emissions when burned in unison with the current fiberboard container and liner and that PM2.5 constitutes a vast majority of the particulates emitted. Targeted replacement of MRE constituents may be more effective in reducing volatile organic compound (VOC) and polycyclic aromatic hydrocarbon (PAH) emissions than the variation of fiberboard packaging designs, while …

Forensic Schedule Analysis Of Construction Delay In Military Projects In The Middle East, James W. Forbes

Theses and Dissertations

This research performs forensic schedule analysis of delay factors that impacted recent large-scale military construction projects in the Middle East. The purpose of this study is to understand the most significant causes of project delay and how AFCEC might improve schedule management performance. The methodologies for analysis are adapted from the Professional Practice Guide to Forensic Schedule Analysis, particularly Method 3.7 Modeled/Additive/Multiple Base, or Time Impacted Analysis—Adjusted. The data is gathered from USACE and AFCEC, consisting of Primavera project schedules and project documents from the Resident Management System database. The project delays from two large-scale projects are apportioned as compensable, …

Analysis Of A Near Real-Time Optimal Attitude Control For Satellite Simulators, Ryan M. Patrick

Theses and Dissertations

Dynamic optimization of spacecraft attitude reorientation maneuvers can result in significant savings in attitude determination and control system size, mass, and power. Optimal control theory is generally applied using an open loop trajectory which is vulnerable to disturbances. A closed loop implementation of optimal control has been difficult to achieve due to the computational requirements needed to quickly compute solutions to the optimal control problem. This research focuses on evaluating a near real-time optimal control (RTOC) system for large angle slew maneuvers on the Air Force Institute of Technology's spacecraft simulator called SimSat. A near RTOC algorithm computes optimal control …

Neutron Versus Gamma Radiation Effects On Ytterbium-Doped Optical Fibers, Olivia M. Borman

Theses and Dissertations

Multimode ytterbium-doped optical fibers (YDFs) are increasingly utilized in military applications involving fiber lasers and amplifiers. YDFs were irradiated with three different radiation sources (neutron, gamma, and mixed gamma/neutron) in order to determine the independent effects that gamma and neutron radiation have on the fibers. The transmission spectra of the fibers were measured during each irradiation and the spectral shapes and attenuation were compared at similar doses. Comparisons of the spectra showed that gamma radiation results in increased attenuation over the 550-975 nm wavelengths. Fast neutrons were found to contribute to increased attenuation near 500 nm. Neutron radiation also caused …

Analysis Of Neutron Effects For Asteroid Disruption, Aaron J. Ferguson

Theses and Dissertations

The use of nuclear weapons is one possible method for disrupting or deflecting an asteroid on a trajectory to impact the earth. A largely unexplored component of weapon yield in a disruption scenario is the impact of the neutron output. The results of MCNP-6 simulations are presented demonstrating the effect that incident neutron energy has on the total energy deposited in an asteroid, including that the efficiency of energy deposition in a material is inversely proportional to the incident neutron energy due to negative Q-value reactions. The effects of material composition on the total energy deposited as well as the …

Optically Stimulated Luminescence From Ag-Doped Lithium Tetraborate (Li2B4O7), Ember S. Maniego

Theses and Dissertations

Silver-doped lithium tetraborate (Li₂B₄O₇) crystals emit optically stimulated luminescence (OSL) in response to stimulating light around 400 nm. Photoluminescence, optical absorption, and electron paramagnetic resonance (EPR) were used to identify the defects in the crystal that cause this OSL. Lithium tetraborate crystals have Ag⁺ ions at Li⁺ sites and at interstitial sites. Upon ionization at room temperature via x rays, electron-hole pairs are generated. The electrons are trapped at Ag⁺ occupying interstitial sites, while the holes are trapped at Ag⁺ at lithium sites. The trapped electron centers become Ag^{0 …}

Nuclear Forensics Applications Of Principal Component Analysis On Micro X-Ray Fluorescence Images, Sarah T. Castro

Theses and Dissertations

A method is developed for rapid detection and analysis of actinides and correlated materials in nuclear fallout debris using principal component analysis on quantified micro x-ray fluorescence intensity values. This method is then applied to address goals of nuclear forensics. The first implementation is a collaborative effort with the National Institute of Standards and Technology and the Federal Bureau of Investigation Laboratory to produce a standard reference material that is a surrogate for glassy nuclear fallout debris in a modern urban environment. This reference material will enable researchers in the development and validation of nuclear forensics methods. A method for …

Improved Performance By The Tie-Gcm With The Inclusion Of Helium As A Major Species, Fredrick R. Schmidt

Theses and Dissertations

When considering the neutral constituents in the upper thermosphere and exosphere, helium needs to be accounted for as a major species. As detailed by Emmert [2015], most first-principle models do not consider helium a major species when solving for diffusion and collisions within the atmosphere. First-principle, physics-based models hold a distinct advantage of seasonal variations and spatial resolution over empirical models which leads to a more realistic depiction of the atmosphere. The National Center for Atmospheric Research’s (NCAR) self-consistent, physics-based Thermosphere-Ionosphere-Electrodynamic General Circulation Model (TIE-GCM) has been updated to take into account this neutral constituent in its calculations. The major …

Evaluation Of The Visible Infrared Imaging Radiometer Suite (Viirs) Cloud Base Height (Cbh) Pixel-Level Retrieval Algorithm For Single-Layer Water Clouds, Kyle E. Fitch

Theses and Dissertations

Evaluation of the Visible Infrared Imaging Radiometer Suite (VIIRS) Cloud Base Height (CBH) product was accomplished. CBH is an important factor for aviation, but a lack of coverage for ground-based retrieval is a significant limitation. Space-based retrieval is essential; therefore, the VIIRS CBH pixel-level retrieval algorithm was assessed for single-layer water clouds. Accurate (truth) measurements were needed not only for the CBH product, but also for VIIRS cloud optical thickness (COT), effective particle size (EPS), and cloud top height (CTH). Data from Atmospheric Radiation Measurement (ARM) sites were used, with VIIRS-ARM matchups created from June 2013 through October 2015 for …

Application Of Non-Rated Line Officer Attrition Levels And Career Field Stability, Christine L. Zens

Theses and Dissertations

The Air Force monitors the strength of its active duty officer force and attempts to achieve the difficult challenge of employing a diversity of talent among career specialties and experience levels. This study completes two objectives, predicting future manning levels for 23 career fields, and providing a statistical framework to assess the stability of these fields. The first part of the study applies regression and survival analysis to subpopulations within the active duty Air Force officer corps, and then aggregates them by year to forecast future personnel levels. Four career fields are considered, including Acquisitions (ACQ), Logistics (LOG), Support (SPT), …

Lifecycle Cost Evaluation Of Flexible Facility Designs, Trevor P. Ellis

Theses and Dissertations

The purpose of this research is to ascertain the type of facility design, standard, robust, or flexible, that yields the greatest lower lifecycle costs (LCC) savings to the USAF. To this aim, the researcher constructed a Monte Carlo simulation to determine the LCC for flexible, robust, and standard administrative facility designs for thousands of potential facility lifecycles. The simulation also illustrates the circumstances under which each type of design would result in the lowest LCC. The results of this research will show the USAF the importance of focusing on LCC and designing flexible facilities. Standard and robust designs are the …

Determining Air Base Installation Capacity Through Multivariate Analysis, Perry L. Cansick

Theses and Dissertations

Per the Air Force Strategic Master Plan, the Air Force will adjust their current basing structure to provide the most effective and efficient installations to support national defense objectives. The Air Force may be required to make strategic basing decisions that close installations and relocate missions to achieve an optimal basing structure. However, before making these decisions, the Air Force needs to have a comprehensive understanding of installation capacity. This research provides an operational definition of installation capacity, which is necessary for measuring installation-level, infrastructure capacity. Using this definition, the research evaluates a set of capacity indicators using principal component …

An Economic Analysis Of The Transition Of A Contingency Military Installation To An Enduring Status Using Monte Carlo Simulations, Ryan M. Amedee

Theses and Dissertations

The construction of expeditionary bases is central to Department of Defense’s (DoD) responses to contingency operations. Usually expected to be transitory, expeditionary bases are constructed with temporary materials that can be erected quickly. The Global War on Terrorism is entering its fifteenth year and bases within Central Command that were expected to be temporary have provided an enduring presence. The decision to transition a base from temporary to semi-permanent or permanent is difficult, as it requires substantial capital investment for facility construction. This decision is further complicated by unknown mission durations. The DoD has attempted to reduce the decision’s complexity …

Removal Of Perfluorooctanoic Acid From Water Using Primitive, Conventional And Novel Carbonaceous Sorbent Materials, Christopher K. Brown

Theses and Dissertations

Polyfluoroalkyl Substances (PFAS), like perfluorooctanoic acid, have been used for the last 50 years in a wide variety of industrial processes and consumer-based products, including polymer additives, lubricants, fire retardants and suppressants, pesticides, and surfactants (Buck et al. 2015). The Department of Defense (DoD) has used PFAS-based Aqueous Film Forming Foam (AFFF) at fire training facilities and aircraft hangars. AFFF has contaminated approximately 600 sites classified as fire training facilities with PFAS (Huang, 2013).

This study focused on testing the most likely carbonaceous adsorbent compounds to remediate PFAS-contaminated sites on Air Force installations. Batch tests were performed to determine the …

Validation And Improvement Of Reliability Methods For Air Force Building Systems, Patrick A. Deering

Theses and Dissertations

The United States Air Force manages its civil infrastructure resource allocation via a two-dimensional risk model consisting of the consequence of failure and reliability. Air Force civil engineers currently use the BUILDER® Sustainment Management System to estimate and predict reliability at multiple levels within its civil infrastructure systems. Alley (2015) developed and validated a probabilistic model to calculate reliability at the system level. The probabilistic model was found to be a significant improvement over the currently employed BUILDER® model for four major building systems (electrical, HVAC, fire protection, and electrical). This research assessed the performance and accuracy of both the …

Evaluating Storm Sewer Pipe Condition Using Autonomous Drone Technology, Maria T. Meeks

Theses and Dissertations

The United States Air Force (USAF) owns a total of 30.9 million linear feet (LF) of storm sewer pipes valued at approximately $2.3B in its vast portfolio of built infrastructure. Current inventory records reveal that 78% of the inventory (24.1 million LF) is over 50 years old and will soon exceed its estimated service life. Additionally, the USAF depends on contract support while its business processes undervalue in-service evaluations from long-term funding plans. Ultimately, this disconnect negatively impacts infrastructure performance and overall strategic success, and the USAF risks making uninformed decisions in a fiscally constrained environment.

This research presents a …

Liquid Fuel Film Cooling: A Cfd Analysis With Hydrocarbon Fuel, Jacob D. Bills

Theses and Dissertations

Cooling of liquid rocket engine combustion chambers and nozzles is a critical component to liquid rocket engine design. A common method of cooling is liquid fuel film cooling. Liquid fuel is injected along the surface of the wall to act as a barrier against the core combustion gases. A numerical model is developed for simulating liquid fuel _lm cooling in a rocket engine using a hydrocarbon fuel. The model incorporates turbulent multiphase ow with species transport within the commercial ANSYS® Fluent CFD software. Conjugate heat transfer is simulated through walls containing embedded cooling channels. A novel User Defined Function is …

Conceptual Design, Structural Analysis, And Design Space Exploration Of A Vacuum Lighter Than Air Vehicle, Brian C. Cranston

Theses and Dissertations

The research detailed in this study investigates an internal vacuum as well as its optimal structural design, utilizing currently available materials, as an alternative to traditional gases to create and sustain buoyancy in lighter than air vehicles. To date, the consideration of a vacuum lighter than air vehicle has been limited to three sources of literature, the earliest of which dates back to 1663. This study will initially summarize and review this literature. We will then combine finite element analysis, dimensional analysis, design of experiments, and response surface methodology studies to explore the feasibility, and the functional design of a …

Spectroscopic Measurement Of Gas Temperature In Small Internal Combustion Engines, Matthew J. Deutsch

Theses and Dissertations

The Small Engine Research Bench (SERB) was used previously to measure spatially and temporally averaged heat flux, as well as local, instantaneous heat flux at several external locations, for a series of small engines (1 - 10 kW). This investigation obtained time averaged crank angle resolved measurements of the in-cylinder gas temperature using Fourier transform infrared (FTIR) absorption thermometry. The results, coupled with heat flux measurements, will enable the validation or refinement of existing thermal energy loss models.

Effects Of Additive Manufacturing Methods On The Dynamic Properties Of 15-5ph Stainless Steel, Allison A. Dempsey

Theses and Dissertations

Experimental research was conducted to determine the dynamic properties and characterize the microstructure of 15-5PH Stainless Steel manufactured through Direct Metal Laser Sintering (DMLS) additive manufacturing (AM) processes and heat treated using common heat treatment protocols. A thorough understanding of the material's properties is necessary before such parts are utilized in an operational capacity. Of the five builds, two deviated significantly from the specified composition of 15-5PH stainless steel. The remaining three builds, possessing the desired composition and crystalline structure, were tested in compression and tension at two strain rates. Tension tests using a reflected wave and a momentum trap …

Surface Roughness Of Electron Beam Melting Ti-6al-4v Effect On Ultrasonic Testing, Evan T. Hanks

Theses and Dissertations

Experimental research was conducted on the effects of surface roughness on ultrasonic non-destructive testing of Electron Beam Melted (EBM) additively manufactured Ti-6Al-4V. Additive Manufacturing (AM) is a developing technology with many potential benefits, but certain challenges posed by its use require further research before AM parts are viable for widespread use in the aviation industry. Possible applications of this new technology include, Aircraft Battle Damage Repair (ABDR), small batch manufacturing to fill supply gaps, and replacement for obsolete parts. The research presented here assesses the effectiveness of ultrasonic inspection in detecting manufactured flaws in EBM manufactured Ti-6Al-4V. EBM products are …

Effectiveness Based Design Of A Tactical Tanker Aircraft, Andrew K. Petry

Theses and Dissertations

An approach to drive conceptual aircraft design using mission effectiveness parameters is described and applied to an operational scenario. The scenario includes traditional aircraft refueling tankers and a proposed tactical tanker concept supporting fighter aircraft conducting offensive (OCA) and defensive (DCA) counter air patrols. Traditional conceptual design methodologies were used to generate a baseline design for a tactical tanker aircraft, which was evaluated using a MATLAB-based model to investigate Measures of Effectiveness (MOE). The model holds the traditional tanker and fighter capabilities constant, while varying the tactical tanker's specific fuel consumption, lift-to-drag ratio, fuel payload, mass fraction, and proximity to …

Design And Flight Test Of A Weapons-Cavity Acoustics And Separation Test Bed, Zachary Probst

Theses and Dissertations

Two very important, and often detrimental, phenomena can occur when an open weapons bay, or more generally-a cavity, is exposed to high-velocity flow. First, a shear layer develops over the cavity, leading to large regions of difficult-to-predict flow. Second, dynamic pressure oscillations are generated within the cavity itself. These two issues can combine to have multiple harmful effects on weapons carriage and employment. This provided motivation for flight tests which quantify forces and moments on a store, mounted at various positions in the cavity, for a variety of flight conditions. Specifically, a low-cost, easily reconfigurable test bed for weapons-cavity research …

Influence Of Coolant Flow Rate Parameters In Scaling Gas Turbine Cooling Effectiveness, Connor J. Wiese

Theses and Dissertations

Film cooling scheme development for use in gas turbine engines often entails the characterization of adiabatic wall temperature distributions in order to determine the driving temperatures for the convective heat transfer processes in the engine. For convenience, adiabatic effectiveness experiments are often performed near room temperature and presumed to scale the engine condition. In order to perform these experiments, researchers elect to match the freestream Reynolds number to that of the engine. When scaling to engine temperatures, however, coolant and freestream fluid properties both change nonlinearly. Therefore the ratio of these properties does not remain constant as the temperature changes. …

Investigation Into Active Spanwise Camber Deformation On The Lateral Stability And Roll Control Of The X-56a Compared To Conventional Ailerons, Eric T. Yerly

Theses and Dissertations

"This research compares the stability and roll characteristics of an X-56A using AFRL’s Variable Camber Complaint wing technology to actively change wing camber compared to conventional ailerons deflected at set angles. An analysis of the stability and roll characteristics was modeled using a 3-D vortex lattice theory simulation, and that data was compared to wind tunnel testing to verify and validate the model results. Wind tunnel data was collected using 19 inch 3-D printed scale models with wings fabricated with a pre-determined percentage of camber deformation, as well as models with fixed aileron deflections. The full span model changed camber …

Force And Moment Measurements Applicable To A Flexible Weapons System, James B. Sellers

Theses and Dissertations

Continuing the development of the 6-DOF Motion Test Apparatus (MTA) for performing dynamic wind tunnel tests revealed the importance of a capable data acquisition (DAQ) system for collecting and analyzing data. Assembling and testing the DAQ system in conjunction with the MTA, AFIT Low-Speed Wind Tunnel, and a selection of high-performance sensors was the primary focus of this research. Specifically, acquiring time-accurate aerodynamic force and moment measurements on a variety of test models was of high importance. With the established real-time DAQ system hardware, a National Instruments (NI) LabVIEW program was created to acquire data from an ATI Nano25-E force …

College Of Engineering News, Georgia Southern University

College of Engineering & Computing: News & Publications (2010-2023)

• Amazon award to IT’s Russell Thackston