Engineering Commons^™

Deep Learning To Predict The Hydration And Performance Of Fly Ash-Containing Cementitious Binders, Taihao Han, Rohan Bhat, Sai Akshay Ponduru, Amit Sarkar, Jie Huang, Gaurav Sant, Hongyan Ma, Narayanan Neithalath, Aditya Kumar

Electrical and Computer Engineering Faculty Research & Creative Works

Fly ash (FA) – an industrial byproduct – is used to partially substitute Portland cement (PC) in concrete to mitigate concrete's environmental impact. Chemical composition and structure of FAs significantly impact hydration kinetics and compressive strength of concrete. Due to the substantial diversity in these physicochemical attributes of FAs, it has been challenging to develop a generic theoretical framework – and, therefore, theory-based analytical models – that could produce reliable, a priori predictions of properties of [PC + FA] binders. In recent years, machine learning (ML) – which is purely data-driven, as opposed to being derived from theorical underpinnings – …

Wind Effects On Dome Structures And Evaluation Of Cfd Simulations Through Wind Tunnel Testing, Tiantian Li, Hongya Qu, Yi Zhao, Ryan Honerkamp, Guirong Grace Yan, Arindam Chowdhury, Ioannis Zisis

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

In the Study, a Series of Wind Tunnel Tests Were Conducted to Investigate Wind Effects Acting on Dome Structures (1/60 Scale) Induced by Straight-Line Winds at a Reynolds Number in the Order of 106. Computational Fluid Dynamics (CFD) Simulations Were Performed as Well, Including a Large Eddy Simulation (LES) and Reynolds-Averaged Navier–Stokes (RANS) Simulation, and their Performances Were Validated by a Comparison with the Wind Tunnel Testing Data. It is Concluded that Wind Loads Generally Increase with Upstream Wind Velocities, and They Are Reduced over Suburban Terrain Due to Ground Friction. the Maximum Positive Pressure Normally Occurs Near the Base …

Modeling Vehicle-Miles Of Travel Accounting For Latent Heterogeneity, Fatemeh Nazari, Abolfazl (Kouros) Mohammadian

Civil Engineering Faculty Publications

Vehicle use is associated with negative externalities such as traffic congestion, air pollution, and greenhouse gas emissions. Particularly in the U.S. as a car-oriented country, vehicle use — in terms of vehicle-miles of travel (VMT) — has been on the rise and is projected to increase in the future. To curb the VMT growth and mitigate the associated externalities, policy makers can design informed strategies based on VMT predicted by vehicle use models. However, traditional vehicle use models capture merely the observed heterogeneity across vehicle decision making units (e.g., individuals) and ignore the latent or taste heterogeneity sourced in …

Incoherency In Central American Hydroclimate Proxy Records Spanning The Last Millennium, Jonathan Obrist-Farner, Byron A. Steinman, Nathan D. Stansell, Jeremy Maurer

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Continued Global Warming is Expected to Result in Reduced Precipitation and a Drier Climate in Central America. Projections of Future Changes Are Highly Uncertain, However, Due to the Spatial Resolution Limitations of Models and Insufficient Observational Data Coverage Across Space and Time. Paleoclimate Proxy Data Are Therefore Critical for Understanding Regional Climate Responses during Times of Global Climate Reorganization. Here We Present Two Lake-Sediment based Records of Precipitation Variability in Guatemala Along with a Synthesis of Central American Hydroclimate Records Spanning the Last Millennium (800–2000 CE). the Synthesis Reveals that Regional Climate Changes Have Been Strikingly Heterogeneous, even over Relatively …

Solar Farm Utilizing A Battery Energy Storage System, Hannah Nicole Bonderov

Master's Theses

According to the US Energy and Information Administration, between 2022-2023 60% of planned new electricity generation consists of solar farms with a battery energy storage system [1]. The demand for these paired systems has increased since batteries can be charged during the day with the energy captured from the solar farm then released to the customer in the evening during peak energy demand. This achieves peak load shaving which reduces the cost of electricity for the customer and is ecologically friendly.

This thesis aims to create an efficient solar farm with a battery energy storage system for a farmer in …

Shelfaware: Accelerating Collaborative Awareness With Shelf Crdt, John C. Waidhofer

Master's Theses

Collaboration has become a key feature of modern software, allowing teams to work together effectively in real-time while in different locations. In order for a user to communicate their intention to several distributed peers, computing devices must exchange high-frequency updates with transient metadata like mouse position, text range highlights, and temporary comments. Current peer-to-peer awareness solutions have high time and space complexity due to the ever-expanding logs that each client must maintain in order to ensure robust collaboration in eventually consistent environments. This paper proposes an awareness Conflict-Free Replicated Data Type (CRDT) library that provides the tooling to support an …

Assessment Of Emergency Cooling Requirement For Nuclear Reactor Loss-Of-Coolant Accidents, Michael T. Lindsay

Theses and Dissertations

The 2022 Russia-Ukraine War marks the first time in modern history of conventional military forces targeting and seizing control of an operational nuclear power plant. Power supply and operational cooling systems are critical to avert reactor loss-of-coolant accidents (LOCA) in the event of emergency shutdown, or SCRAM. A wartime non-design based reactor accident causing loss of reactor power and coolant supply would require an emergency heat exchange via coolant to mitigate reactor core heat. At present, the military does not have a well-defined model which characterizes this requirement for operational planning should such an event occur. SCALE 6.2.4 is used …

Pulsed Power Neutron Production With Deuterated Polymer Accelerator Targets, Anthony O. Hagey

Theses and Dissertations

This document presents an investigation of the effect of deuterated polyethylene accelerator targets on the neutron fluence from a local mass injection dense plasma focus driven by the United States Naval Research Laboratory’s Hawk pulsed-power generator. After successful production of thin targets, the acquisition of thicker targets, and testing inside Hawk, it was found that the presence of a deuterated polyethylene target increased the neutron fluence. Results suggested that fluence can significantly increase with the presence of a deuterated target vs a nondeuterated target. Additive manufacturing printing was used as a production method in order to determine if deuterated accelerator …

Modeling Radiation Exposure On Flight Missions To Analyze Aircrew Risk, Camila V. Quintero Hilsaca

Theses and Dissertations

GCR and SPE comprise the majority of the ionizing radiation experienced in the upper atmosphere within flight-altitude environments. Although previous studies have analyzed radiation doses from single sources on civilian flight operations, there is a lack of research focused on dose received by military personnel during flight from both sources simultaneously. In-flight radiation environments are modeled through the MCNP6 for two separate aircraft, an Air Force A-10 and a Boeing 737. Particle fluence values for galactic cosmic rays and solar particle events for four separate flight paths are determined using the CARI-7A software and the SIRE2 toolkit, respectively. MCNP6 code …

Design Of A Miniaturized Cubesat Tt&C Patch Antenna, Thomas A. Butterick

Theses and Dissertations

This effort explored the design of miniaturized rectangular microstrip patch antennas for application as a telemetry, tracking, and control (TT&C) on a CubeSat. The motivation for this research was the Grissom-P CubeSat mission planned by AFIT. The TT&C antenna selected for the mission exceeded the allotted size by over a factor of two. The studies performed included analyses of simply reducing aperture size, altering substrate permittivity, and layered approaches to antenna miniaturization. The primary approach to miniaturization was based on a virtually shorted patch antenna. Other approaches included an edge-shorted, slotted patch and the use of corner truncations for improved …

Classification Tradeoffs In Multispectral Polarimetric Ladar Architectures, Connor B. Martin

Theses and Dissertations

An end-to-end LADAR system is modeled at the waveform level to perform material classification at a per-pixel basis. A K-Nearest Neighbors machine learning algorithm is chosen to make predictions using polarimetric material characteristics as features. A variable receiver design is modeled to allow for the use of multiple configurations of Polarization State Analyzers. This research investigates the inclusion of multiple wavelengths in the transmitted laser pulse to improve classification accuracy. Additionally, the effects of lowering the receiver’s detector bandwidth are investigated. Through the classification process, transmitting a multispectral laser pulse is shown to improve classification and may improve future LADAR …

The Electromagnetic Bayonet: Development Of A Scientific Computing Method For Aperture Antenna Optimization, Michael P. Ingold

Theses and Dissertations

The quiet zone of a radar range is the region over which a transmitted EM field approximates a uniform plane wave to within some finite error tolerance. Any target to be measured must physically fit within this quiet zone to prevent excess measurement error. Compact radar ranges offer significant operational advantages for performing RCS measurements but their quiet zone sizes are constrained by space limitations. In this work, a scientific computing approach is used to investigate whether equivalent-current transmitters can be designed that generate larger quiet zones than a conventional version at short range. A time-domain near-field solver, JefimenkoModels, was …

Modeling The Effects Of Radiation On Microelectromechanical Resonators, David D. Lynes

Theses and Dissertations

As the use of MEMS becomes more prolific in air, space, defense, and power applications, they will be exposed to more extreme radiation environments. This dissertation explores the effects of ionizing and nonionizing radiation on MEMS. AlN-on-Si based piezoelectric bulk acoustic wave resonators were irradiated by gamma-rays and silicon ions while measuring S-parameters in situ. Changes to the resonator and equivalent circuit parameters are extracted. The resonators demonstrated resilience against the effects of radiation-induced charge trapping. However, radiation-induced atomic displacements caused shifts to resonant frequency. From these data, an atomistic model is derived to describe the relationship between radiation type …

Fast And Accurate 3d Object Reconstruction For Cargo Load Planning, Adam R. Nasi

Theses and Dissertations

Cargo load planning involves efficiently packing objects into aircraft subject to constraints such as space and weight distribution. Currently, this is performed manually by loadmasters. The United States Air Force is investigating ways to automate this process in order to improve airlift operational readiness while saving money. The first step in such a process would be generating 3D reconstructions of cargo objects to be used by a load planning algorithm. To that end, this thesis presents a novel method for fast, scaled, and accurate 3D reconstruction of cargo objects. This method can scan a 2.5m×3m×2m object in less than 10 …

Characterizing Location-Based Electromagnetic Leakage Of Computing Devices Using Convolutional Neural Networks To Increase The Effectiveness Of Side-Channel Analysis Attacks, Ian C. Heffron

Theses and Dissertations

SCA attacks aim to recover some sort of secret information, often in the form of a cipher key, from a target device. Some of these attacks focus on either power-based leakage, or EM-based leakage. Neural networks have recently gained in popularity as tools in SCA attacks. Near-field EM probes with high-spatial resolution enable attackers to isolate physical locations above a processor. This enables attackers to exploit the spatial dependencies of algorithms running on said processor. These spatial dependencies result in different physical locations above a chip emanating different signal strengths. The strengths of different locations can be mapped using the …

Belief Space Planning For Alternative Navigation In Gnss-Denied Environments, Timothy I. Machin

Theses and Dissertations

Robust alternative navigation for autonomous agents becomes critical without reliable GNSS. Autonomous agents utilize measurement updates to constrain uncertainty. Belief space planning builds graph structures of beliefs within environments based on probable paths, agent and measurement models, and information of the environment. The Rapidly-exploring Random Alt-Nav Belief Graph (RRBANG) algorithm leverages stochastic filtering to implement a range of alt-nav measurement capabilities for robust navigation in GNSS-denied environments.

Robust Feature Matching For Visual-Based Aerial Navigation Using Registered Imagery, Luis Montenegro

Theses and Dissertations

This work leverages the SIFT detector along with known robust feature matching techniques for vision-aided sUAS navigation solutions. The proposed algorithm focuses on a sufficient number of features extracted, their quality and their distribution.

Magnetic Anomaly Mapping For Navigation, Luke T. Bergeron

Theses and Dissertations

Magnetic navigation (MagNav) has the potential to provide a global form of navigation that uses magnetic measurements of the Earth’s anomaly magnetic field and compares those measurements to a magnetic anomaly map in order to determine the user’s position. Widespread use of MagNav will require a database of fully-sampled, low-altitude magnetic anomaly maps. Existing magnetic anomaly map databases usually come from under- or poorly-sampled surveys. In this work, we provide an easy to follow MagNav anomaly map generation framework and set of survey collection metrics/requirements in an effort to help facilitate and standardize the creation of such a database. We …

Classifying Open-Air Target Measurements Using Simulation-Trained Convolutional Neural Networks, Matthew M. Rofrano

Theses and Dissertations

This research focuses on the development of machine learning networks that can identify and classify airborne targets using their radar cross section response. Simulation and measurement data for five targets was collected using Altair's CadFEKO software, and the Air Force Institute's Compact Radar Range. Three machine learning models were trained using simulation data, and evaluated using the collected measurement data. Variability is introduced to the training data by applying random gaussian noise to simulation results. Gaussian noise is added to the measurement data prior to evaluation in-order to model "hostile noise jamming." Network performance is measured against a baseline performance …

Topological Variability In Water Distribution Networks, James M. Anderson

Theses and Dissertations

Water distribution networks are critical infrastructure characterized by difficulties in their assessment and deteriorating performance due to aging components. Resilience analysis of networked infrastructure has replaced traditional risk analysis to focus on performance. Global Resilience Analysis can provide useful information to decision makers and system managers regarding repair and expansion of networks. Network performance has been found to be directly informed by network structure. This work leverages graph theory to assess network qualities that correlate with resiliency characteristics across 69 real world water networks. These networks are then grouped by their structural properties through k-means clustering and compared using parametric …

Protection Of Linear Assets In Arctic Regions Using Basic Expeditionary Airfield Resources (Polaar Bear), Christopher P. Lintz

Theses and Dissertations

In the 2018 United States National Defense Strategy, the Department of Defense mandated that forces are to be more dynamic and decentralized. The Arctic region was a key topic that was addressed. This means that in the future, it is possible that personnel will need to operate in the Arctic, away from the standard built up infrastructure, to enhance the capabilities of the Air Force and enable the power projection required for mission execution. When establishing a new location, water systems are one of the first requirements for setting up a temporary base infrastructure. However, the Air Force’s current expeditionary …

Using Embedded Systems And Augmented Reality For Automated Aerial Refueling, Nathaniel A. Wilson

Theses and Dissertations

The goal of automated aerial refueling (AAR) is to extend the range of unmanned aircraft. Control latency prevents a human from remotely controlling the receiving aircraft as it approaches a tanker. To conform with the size, weight, and power constraints of a small unmanned aircraft, an AAR system must execute in real-time on an embedded platform. This thesis explores the timing and computational performance of a NVIDIA Jetson AGX Orin to a state-of-the-art general-purpose computer using existing AAR algorithms. It also constructs an augmented reality framework as an intermediate step for testing vision-based AAR algorithms between virtual testing and expensive …

Atmospheric Polarization And Solar Position As Kalman Updates To A Navigation Solution, Thomas J. Wheeler

Theses and Dissertations

Simulation and physical testing of a sensor that measures relative position of the Sun and polarization of light in the atmosphere as a navigational aid in a Kalman filter.

Environmental Trade-Offs Of Reverse Osmosis Water Purification Units (Rowpus) And Bottled Water, Caleb A. Boone

Theses and Dissertations

The Department of Defense (DoD) conducts many remote missions around the globe. As part of any remote basing strategy, potable water needs to be secured. Currently, there are three primary means of procuring potable water at remote locations: bottled water, on-site purification, or tie-in to existing, local infrastructure. The purpose of this study is to determine the environmental tradeoffs of bottled water and on-site treatment via a Reverse Osmosis Water Purification Unit (ROWPU), which uses multiple levels of filtration to make potable water from freshwater or saline water. A cradle-to- gate assessment was developed for both systems to create a …

An Analysis On Recommended United States Air Force Additive Manufacturing Construction Unit Type Code Package For Expeditionary Deployment, Caleb G. Dann

Theses and Dissertations

Additive Manufacturing Construction (AMC) is an emerging technology in the construction industry which utilizes 3-D printing to reduce costs, labor requirements and deviations in quality. This technology has the ability to rapidly produce repeatable construction projects while tailoring each to specific requirements through the use of 3-D designs. One of the primary objectives of the 2018 National Defense Strategy (NDS) is to continue meeting mission demands with a greater focus on the efficient use of resources. AMC has the ability to satisfy the requirements of this objective. The United States Air Force has begun initial print trials but have not …

Investigation Of Rhine Pointing As A Solution To The Aircraft Human Machine Interface Problem, Alexandra C. Dobranski, Samuel J. Medvec

Theses and Dissertations

The human machine interface in 5th generation aircraft has not evolved proportionally with advances in display size and data density. The traditional cursor slew method fails to rapidly relocate the cursor, especially on large displays. Previous studies at the Air Force Test Pilot School and Air Force Institute of Technology identified methods that have the potential to improve the human machine interface. This research expanded upon those studies by providing an assessment of head tracking technology as a secondary method of cursor manipulation. Specifically, this study examined the effects that visual feedback (visible and invisible head tracking cursors) and cursor …

Temporal And Spatial Variability Of Specific Energy Consumption For Atmospheric Water Generators, Anthony T. Brenes

Theses and Dissertations

Atmospheric Water Generators (AWG) produce potable water from the moisture in the air, providing a potentially viable water source in austere locations or emergency response scenarios. In this study, the operating constraints of three existing commercially available AWG devices are investigated, compared to historical weather data from across the continental United States. Utilizing linear regression modeling and weather station data for the years of 1985-2019, the monthly and spatial trends of energy demand to produce water from these devices are evaluated. Energy and water production efficiencies for the devices are highly dependent on environmental conditions with relative humidity and temperature …

A Systems Modeling Approach To Support Human-Agent Team Performance For Combat Identification, Clayton W. Couch

Theses and Dissertations

Combat Identification (CID) in an air-to-air combat context is a highly complex cognitive task that requires the operator to make rapid, high consequence decisions. To accomplish CID, fighter aircrew must attend to and perceive a broad range of information while concurrently building situation awareness (SA) and conducting other tasks. While existing automated agents are available to help fighter aircrew with this CID task, they are designed for a very narrow subset of the overall task and are not well suited for human-agent teaming. An interdependence analysis of the human operator and supporting machine agents conducted for this task support the …

Civilian And Military Civil Engineer Mission In The Space Domain, Linda E. Kuster

Theses and Dissertations

Military and civil interest in space-based operations has increased dramatically in recent years due to the discovery of life sustaining properties such as water on Mars and advancements in cyber technology. Civilian sector discussions and research have centered on the establishment of permanent extraterrestrial infrastructure, while discussions from the military perspective have focused on providing reliable, resilient infrastructure, capable of withstanding cyber-based and kinetic attacks. Both perspectives account for known threats and sustainment methods required to ensure success in the space domain. With the existence of threats for the military and civilian missions, civil engineers will undoubtedly be critical to …

Mission Dependency Weighted Water Distribution Networks, Payten A. Connally

Theses and Dissertations

How does the United States Air Force (USAF) assess and plan to replace their most critical drinking water infrastructure? The historical answer is to wait for it to break and then replace or repair the failed pipe. While this has been the process in the past, it is no longer a sustainable approach with resources and funding becoming more constrained in the public and private sectors, and aging assets approaching the end of their usable life. The USAF has taken the first step in asset management to identify their underground water lines, but they have not developed ways to convey …