Engineering Commons^™

Ultra Wide Band Gap Oxides For Advanced Optoelectronics And Supercapacitor Applications: A Case Study Of Intrinsic And Doped Germanium Dioxide, Paul Gaurav Nalam

Open Access Theses & Dissertations

Germanium dioxide (GeO2) is a metal oxide semiconductor with multiple polymorphs that has recently garnered a significant amount of scientific attention owing to its novel ultra-wide band gap and pseudo-capacitive properties, which can potentially transcend current power electronic, optoelectronic, and supercapacitor technologies. However, due to the difficulty in the synthesis of stable crystalline phases of individual polymorphs of GeO2 thin films, this material system demands complex and resource-intensive deposition techniques to synthesize. An attempt was made to develop cost-effective and scalable deposition techniques to stabilize specific crystalline phases of GeO2 thin films. These phases were further structurally fine-tuned to state …

Effects Of Simultaneous Co2 Addition To The Fuel And Oxidizer Streams On Soot Formation In Co-Flow Diffusion Ethylene Flame, Yu Yang, Shu Zheng, Yuzhen He, Hao Liu, Ran Sui, Qiang Lu

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Soot formation in a co-flow diffusion ethylene flame with the addition of CO₂ to the fuel (the CO₂-F), oxidizer (the CO₂-O), and fuel/oxidizer (the CO₂-F/O) streams was numerically and experimentally investigated in this study. The effects of different CO₂ addition ways on soot inception, soot condensation, H-abstraction-C₂H₂-addition (HACA) and oxidation by O₂/OH processes, were quantitatively analyzed by introducing the integrated reaction rates over the whole computational domain. The simulated and experimental results showed that the CO₂-F/O was the most effective in inhibiting soot formation …

Gpu Based Monte Carlo Estimation Of Eddy Current Losses In Electromagnetic Coil-Core System, Adwaith Ravichandran

Theses and Dissertations

A novel parallelizable probabilistic approach to model eddy currents in AC electromagnets is presented in this research. Consequently, power loss associated with the formation of these eddy currents is estimated and validated using experimental data. Furthermore, predicting the effect of ferromagnetic alternating field enhancement on power loss in the source excitation winding has been an active area of research. Unlike a stationary field, an alternating sinusoidal field diffuses partially into the ferromagnetic material leading to a predictably sub-optimal field enhancement. To model these physics, finite element techniques employ nonlinear iterative solvers which are time consuming. A novel method is developed …

Safe Navigation Of Quadruped Robots Using Density Functions, Andrew Zheng

All Theses

Safe navigation of mission-critical systems is of utmost importance in many modern autonomous applications. Over the past decades, the approach to the problem has consisted of using probabilistic methods, such as sample-based planners, to generate feasible, safe solutions to the navigation problem. However, these methods use iterative safety checks to guarantee the safety of the system, which can become quite complex. The navigation problem can also be solved in feedback form using potential field methods. Navigation function, a class of potential field methods, is an analytical control design to give almost everywhere convergence properties, but under certain topological constraints and …

2023 Summer-Fall Graduate Recognition Program, Propulsion Research Center, Robert Frederick

PRC Graduate Recognition

This program includes the graduate recognition program for summer and fall 2023. Includes photographs, upcoming events, recent publications, and student profiles.

A System Theoretic Process Analysis Framework And Model Based Approach For Resilient Space Architecture Design, Eric T. Sommer

Theses and Dissertations

As the capabilities provided by space-based systems offer significant contributions toward defense applications, potential adversaries stand to gain significant value in disrupting them. Therefore, the United States must pursue the development and operation of resilient space architectures, capable of delivering capabilities in the face of disruptions. To support this development, systems engineering methods require innovation to effectively ensure design of complex space architectures to meet their objectives. This thesis recommends and demonstrates a System-Theoretic Process Analysis (STPA) framework to qualitatively analyze space architectures. The analysis outputs identify design considerations, requirements, and constraints required for resilience. To enable a model-based systems …

Experiments And Simulations Of Liquid Mass Gauging And Slosh Dynamics In Microgravity, Jedediah Morse Storey

Theses and Dissertations

Advancements in liquid propellant management science and technologies are key to increasing safety, decreasing cost, and increasing payload mass of space missions. Propellant usually comprises a large portion of the total mass of launch vehicles and spacecraft, so liquid propellant sensing, as well as predicting and controlling the motion of it, are important. Electrical Capacitance Tomography (ECT) is an emerging sensing technology that is capable of measuring the distribution of liquid anywhere inside of a tank, potentially making it useful for measuring slosh and gauging mass. An ECT-instrumented tank was successfully tested in microgravity for the first time. Basics of …

Testing And Implementation Of Attitude Determination & Control System For Arksat-1 Cubesatellite, Cassandra Sands

Graduate Theses and Dissertations

ARKSAT-1 is a CubeSatellite (CubeSat) developed at the University of Arkansas and launched to the International Space Station on SpaceX mission SPX-27 launching from Kennedy Space Center as part of the NASA’s 8th CubeSat Launch Initiative CSLI-8. ARKSAT-1’s payload features a high-powered LED, the Solid State Inflatable Balloon (SSIB) deorbiting system applicable to small satellites, and a series of InfraRed and Visible cameras. To point the LED or take images of desired observational targets, the spacecraft will need to be able to determine its orientation within its orbit, as well as rotate. This will be achieved through the use of …

Accelerating Machine Learning Inference For Satellite Component Feature Extraction Using Fpgas., Andrew Ekblad

Theses and Dissertations

Running computer vision algorithms requires complex devices with lots of computing power, these types of devices are not well suited for space deployment. The harsh radiation environment and limited power budgets have hindered the ability of running advanced computer vision algorithms in space. This problem makes running an on-orbit servicing detection algorithm very difficult. This work proposes using a low powered FPGA to accelerate the computer vision algorithms that enable satellite component feature extraction. This work uses AMD/Xilinx’s Zynq SoC and DPU IP to run model inference. Experiments in this work centered around improving model post processing by creating implementations …

Stability And Control Flight Testing Of A Modified Cessna 172, Tatiana Dirrigl Forbes

Theses and Dissertations

The Cessna 172N is a small, fixed-wing, single-engine aircraft. The modified Cessna 172N included a swapped engine to a Lycoming O-360-A4M, tuned exhaust, and variable timing ignition installed. Test flights on this aircraft were performed order to evaluate the stability and control characteristics of the Cessna 172N, and compare them with the regulations in the Title 14 CFR Part 23 Airworthiness Standards for Normal, Utility, Acrobatic, and Commuter Category Airplanes. The flight test consisted of four separate tests performed during a single flight, departing from and returning to Melbourne Orlando International airport (KMLB). The data was collected through static and …

Development Of Load Measurement Technique For Arbitrary Shapes, Quintin J. Cockrell

Master's Theses

Obtaining aerodynamic forces and moments about all three orthogonal axes for arbitrary shapes at arbitrary orientations in a fast manner via a measurement technique specific to Cal Poly’s low-speed wind tunnel to continually obtain the forces and moments under quasi-steady conditions is explored. A Continuous Rotation Technique (CR) uses a 6-DOF load cell and stepper motor to rotate an object about an axis for a complete rotation. The forces and moments acting upon the object pass through the stepper motor and interface plates and recorded by the load cell as the object is rotated continuously a finite number of rotations. …

Parametric Optimization Of A Wing-Fuselage System Using A Vorticity-Based Panel Solver, Chino Cruz

Master's Theses

Aerodynamic topology optimization is a useful tool in the aerodynamic design pro-
cess, especially when looking for marginal gains within a design. One example is
a turboprop racer concept aircraft that is designed with the goal of breaking world
speed records. An optimization framework was developed with the intention of later
being applied to this design. In the early design stages, the optimization framework
must focus on quicker methods of drag estimation, such as a panel codes. The large
number of design variables in topology optimization can exponentially increase func-
tion evaluations and thus computational cost. A vorticity-based panel solver …

Numerical Investigations Of Sco2 Compressor Aerothermodynamics Using A Streamline Curvature Based Throughflow Method, Victor Quintanilla

UNLV Theses, Dissertations, Professional Papers, and Capstones

Supercritical carbon dioxide (sCO₂) has emerged as a promising working fluid for the Brayton power cycle, offering enhanced efficiency due to the high density and low viscosity of carbon dioxide (CO₂) near the critical point. A critical component of the sCO₂ Brayton cycle is the turbomachinery, namely the compressor, which significantly contributes to the efficiency enhancement in the sCO₂ Brayton cycle owing to reduced compression work requirements. Its primary function involves elevating the fluid's pressure, effectively priming it for the subsequent heat addition process from a thermal energy source. However, despite its advantages, challenges …

A Dynamic Scoring Methodology For Morphing Airfoil Designs With Application To A Stalling Scenario, Stone Wachs

UNLV Theses, Dissertations, Professional Papers, and Capstones

Shape Changing Airfoils (SCAs) are a developing technology with potential aircraft applications. Leading aerospace corporations are actively researching SCA capabilities. The necessity for this technology stems from the requirement of control surfaces for safe aircraft control. However, the process of testing and determining optimal SCA designs can be costly and time-consuming. While methodologies exist, they often require specific scenario examples and lack a standard approach. To address this issue, a standardized methodology is needed that can be applied to various applications and scenarios. This methodology consists of computational/experimentally produced data for airfoils, a subjective and strategic scoring equation, an algorithmic …

Optimization Of High-Order Statistical Moment Combinations To Best Represent Spray Flow Particle Probability Density Functions, Amanda Lynn Myers

Theses and Dissertations

Characterizing spray flows has been an issue of interest for years, particularly in regards to fuel injection in engines. Droplet velocity and diameter, among other characteristics, are crucial to understanding spray flows. One approach for determining these quantities in a spray is using a statistical approach that solves for the moments of droplet characteristics as they evolve in space and time. A theoretical probability density function (PDF) can be formulated using various combinations of moments which evolve according to derived moment transport equations (thus evolving the PDF), using the principle of maximum entropy as closure to the system. Building upon …

Task Optimization Utilizing Digital Transformation Concepts - Automation Project Execution Via Agile Methodology, Anthony Steven Maiello

Theses and Dissertations

Task Optimization via the use of automated process improvements is becoming more widespread as more industries lean into the concepts surrounding digital transformation. This shift also necessitates a complementary adaptation in project management methodologies to support the rapid and ever-changing environment, requirements, and innovations. This thesis examines the effectiveness of Agile methodology in managing digital automation projects, with a specific focus placed on process improvements with systems engineering. It accomplished this by contrasting the original model, designed and derived utilizing traditional project management techniques, with the proposed model which is a direct result of the application of Agile project practices. …

Development Of A Potassium Permanganate Catalyst-Infused Fuel Grain For Hydrogen Peroxide Hybrid Thruster Ignition Enhancement, Ryan J. Thibaudeau

All Graduate Theses and Dissertations, Fall 2023 to Present

This thesis describes and addresses the need for reliable ignition in small satellite hybrid propulsion systems using hydrogen peroxide. It describes process of creating custom 3D printed ABS plastic fuel grains with small amounts of catalysts. These catalysts lead to a more reliable and energy-efficient ignition of a hybrid rocked propulsion system using catalyst-infused ABS and high-test hydrogen peroxide (HTP). Hydrogen peroxide is a high-density oxidizer and therefore more volumetrically efficient for a small satellite using hybrid rocket technology when compared to gaseous oxygen (GOX). The traditional ignition methods of hybrid rocket propulsion systems using HTP are compared to and …

In-Situ Optical Measurements Of High Temperature Combustion Plumes, Cara Frischkorn

All Graduate Theses and Dissertations, Fall 2023 to Present

Rocket motors are critical to the human exploration of space and to the United States missile defense systems. The design and manufacturing of these motors requires extensive simulation and testing to assure the motors will perform as intended and to minimize safety risks. Taking data from inside the rocket motors during tests is extremely difficult due to the intense temperatures inside the motor as it burns; most instrumentation cannot survive in this environment. The research discussed in this thesis aims to develop an instrumentation system composed of a fiberoptic cable which conducts light from the interior of a rocket motor …

Kwad - Ksu All Weather Autonomous Drone, Nick Farinacci, Sebastian Gomez, Stewart Baker, Ed Sheridan

Symposium of Student Scholars

"KWAD" or "KSU all-Weather Autonomous Drone" project was sponsored by Ultool, LLC to the KSU Research and Service Foundation to create a lightweight drone capable of capturing HD video during all-weather operations. The conditions of all-weather operation include rainfall of one inch per hour and wind speeds of up to twenty miles per hour. In addition, a global minimum structural safety factor of two is required to ensure the system's integrity in extreme weather conditions. Potential mission profiles include autonomous aerial delivery, topological mapping in high moisture areas, security surveillance, search and rescue operations, emergency transportation of medical supplies, and …

Molecular Dynamics Simulations Of The Spontaneous Deformation And Auxetics Behavior During Tensile Test Of A Nematic Liquid Crystal Elastomer Model, Haoran Wang, Nanang Mahardika

Browse all Datasets

Nematic liquid crystal elastomers (LCEs) are advanced materials known for their shape-changing capability in response to external stimuli such as heat, light and electromagnetic fields. This makes them excellent candidates for applications like soft robotics and energy harvesting. While studies on their physical behavior have shed light on the complex nonlinear mechanics of LCEs, investigations through all-atom molecular dynamics (MD) simulations remain an underutilized avenue compared to experimental and theoretical analyses. This limited use is primarily due to the lack of well-established frameworks for conducting high-fidelity atomistic simulations of LCEs. To bridge this gap, we introduce an all-atom MD simulation …

A New Algorithm For Encounter Generation: Encounters From Actual Trajectories (Enact), James Anthony Ritchie Iii

Theses and Dissertations

There is ongoing research at the Federal Aviation Administration (FAA) and other private industries to examine a concept for delegated separation in multiple classes of airspace to allow unmanned aircraft systems (UAS) to remain well clear of other aircraft. Detect and Avoid (DAA) capabilities are one potential technology being examined to maintain separation. To evaluate these DAA capabilities, input traffic scenarios are needed, but current approaches are limited by the breadth of the traffic recordings available. This thesis derives a new mathematical algorithm that uses great circle navigation equations in an Earth spherical model and an accurate aircraft performance model …

Cubesats For Education, Not Any More #3, Robert J. Twiggs

Robert "Bob" Twiggs STEM Education Collection

A PowerPoint Presentation created by Professor Bob Twiggs titled "CubeSats for Education, Not Any More" from November 22, 2023.

Cubesats For Education, Not Any More #2, Robert J. Twiggs, Aaron Zuckerman

Robert "Bob" Twiggs STEM Education Collection

A PowerPoint Presentation created by Professor Bob Twiggs and Aaron Zuckerman titled "CubeSats for Education, Not Any More" from November 21, 2023.

Steady And Transient Study Of Conjugate Heat Transfer In Regenerative Cooled Nozzle, Khaled Bensayah, Khadidja Kamri

Emirates Journal for Engineering Research

The Heat transfer is one of the most serious challenges that exist in a supersonic nozzle flow. The combustion chamber wall and the nozzle are exposed to high-temperature gases during combustion and gas expansion, which can eventually lead to structural failure. This paper reports a computational study of steady and transient conjugate heat transfer in regenerative water cooled nozzle. Numerical computation solved Reynolds-averaged equations based on RSM-Omega turbulence model coupling with solid-phase heat conduction equation and with coolant-phase. The effect of four inlet cooled approach length 0 inch, 6 inch, 12 inch and 18 inch are studied and validated against …

The Effect Of Vortex Cooling And Injection Parameters On A Bipropellant 3d Printed Thermoplastic Thruster, Mousa A. Aqailan

Thesis/ Dissertation Defenses

This research reports an experimental investigation of the efficiency and cooling performance of a 10Nvortex cooled Propane/Gox bi-propellent thruster designed and tested with different fabrication materials including a thermoplastic combustion chamber, and metal faceplate and nozzle. The study proposes vortex as a possible solution for cooling thrusters made from partially 3D-printed thermoplastic. This enables the vortex injection method to be 3D printed in a single solid piece thruster to minimize the design complexity and reduce weight, production time, and cost compared to conventional cooling methods. Vortex cooling is simply made by changing the direction of propellant injection rather than using …

Improving Our Vision Ii: Building Transparency And Cooperation, Eisenhower Center For Space And Defense Studies

Space and Defense

Workshop on Space Situational Awareness Data Sharing Eisenhower Center for Space and Defense Studies World Security Institute’s Center for Defense Information Secure World Foundation London, United Kingdom, October 2007

This was the second workshop to bring together a range of stakeholders to discuss global needs and capabilities for Space Situational Awareness (SSA). The first workshop was held in September 2006 in Colorado Springs, Colorado. This 2006 workshop was sponsored by the Eisenhower Center for Space and Defense Studies and the World Security Institute’s Center for Defense Information. The 2006 workshop report can be found at the following internet site: http://www.cdi.org/PDFs/SSAConference_screen. …

Space Based Solar Power Workshop, Eisenhower Center For Space And Defense Studies

Space and Defense

Preventing resource conflicts in the face of increasing global populations and demands in the 21st century is a high priority for the United States (U.S.) Department of Defense (DOD). All solution options to these challenges should be explored, including opportunities from space.

Future Of Space Commerce Workshop: Reducing Risks And Fostering Partnerships – Synergies Between Civil, Military, Commercial, And New Space, Eisenhower Center For Space And Defense Studies

Space and Defense

Eisenhower Center for Space and Defense Studies Futron Corporation NASA Ames Research Center Breckenridge, Colorado, August 2007

The Future of Space Commerce Workshop brought together participants from the civil, military, commercial, and new space sectors, and relevant academic, consulting, business, and financial organizations to discuss and explore how risks associated with space commerce development can be reduced, and to examine synergies to strengthen and advance partnerships between the sectors. The workshop was hosted by the United States (U.S.) Air Force Academy Eisenhower Center for Space and Defense Studies in cooperation with Futron Corporation and NASA Ames Research Center.

China Working Group: China, Space, And Strategy, Eisenhower Center For Space And Defense Studies

Space and Defense

Eisenhower Center for Space and Defense Studies School of Advanced Air and Space Studies, Air University Keystone, Colorado, June 2007

Chinese advances in its space program in recent years has led to a growing international interest in the implications of Chinese programs in the civil, military, and commercial space sectors. This workshop, sponsored by the United States (U.S.) Air Force Academy Eisenhower Center for Space and Defense Studies and the Air University School of Advanced Air and Space Studies, brought together a community of experts and policy-makers to discuss the implications of current and future Chinese space developments on space …

Summer Space Seminar 2007, Eisenhower Center For Space And Defense Studies

Space and Defense

Eisenhower Center for Space and Defense Studies Space Policy Institute, George Washington University Colorado and Washington, DC, May – June 2007

The Summer Space Seminar 2007 proffered two principal goals: (1) to foster an education and interest in the interdisciplinary areas of space with the intent to develop space professionals now or in the future; and (2) to develop a network of relations across future civil, commercial, and military space professionals that will likely emerge from the participants in the Seminar.