Engineering Commons^™

Path Planning Development Framework For Mobile Robots, Lauren-Ann Elizabeth Graham

Theses and Dissertations

Planetary exploration relies on methods of path planning to achieve autonomous navigation in hazardous environments. Simulating harsh terrain, real-time varying physics, and robotics applications is vital for testing control algorithms here on Earth. Robotics Operating System (ROS) is a set of software libraries and tools that allow you to build and simulate robotic applications. Utilizing ROS, Gazebo, and Blender, a rough terrain simulation framework is created to explore and compare path planning algorithms using various desired robots and maps. ROS supports multiple path planning algorithms given its open-source abilities. This research focuses on path planning implementation of Proportional-Integral-Derivative (PID) control …

An Electric Commerce Platform For Material Testing Laboratories, John Ferris Mitchener

Theses and Dissertations

The emergence of the Internet has allowed businesses to create new sales and marketing channels to provide value for their customers in the marketplace. Engineering manufacturers and suppliers have taken advantage of the internet to automate the customer service aspects of their businesses as well as to market their services in a cost-effective but widespread manner. This work aims to apply the practices and benefits of electronic commerce (e-commerce) to a material testing laboratory through the creation of a functioning website with e-commerce features. The effects of Search Engine Optimization, website accessibility issues, marketing considerations, security concerns, and common business …

Accurate Evaluation Of The Direction-Dependent Mechanical Properties Of Ideal Single Crystals: A Comparative Ab Initio Study, Jaylan Ali Elhalawani

Theses and Dissertations

The mechanical properties of a single crystal or a grain in a polycrystalline material are highly dependent on the direction of the applied load. Key properties of interest are the Young’s modulus and the Poisson ratio in the small strain limit, and the ideal tensile strength in the large strain regime. Prior atomistic computations of these properties interchangeably used two approaches. In one approach the stress-strain response is explicitly calculated via a numerical tensile test experiment. In the second approach the second order single crystal elastic constants are computed via small deformations and then used in analytical equations to derive …

Aerosol Synthesis Of Tungsten Bronze Particles For Nir Shielding, Hao Tu

Theses and Dissertations

This dissertation emphasizes the need for efficient energy use in buildings and transportation due to global warming and the energy crisis. It suggests that improving energy efficiency can help reduce energy consumption and emissions and support sustainability. The dissertation introduces various transparent materials that can block near-infrared (NIR) radiation from solar radiation to save energy and money, and it highlights the growing market value of such products. The dissertation compares tungsten bronze with other NIR shielding materials and shows its advantages. The dissertation introduces a cheap and environmentally friendly method for continuously producing tungsten bronze particles via aerosol synthesis. Particle …

Design, Development And Evaluation Of The Ruggedized Edge Computing Node (Recon), Sahil Girin Patel

Theses and Dissertations

The increased quality and quantity of sensors provide an ever-increasing capability to collect large quantities of high-quality data in the field. Research devoted to translating that data is progressing rapidly; however, translating field data into usable information can require high performance computing capabilities. While high performance computing (HPC) resources are available in centralized facilities, bandwidth, latency, security and other limitations inherent to edge location in field sensor applications may prevent HPC resources from being used in a timely fashion necessary for potential United States Army Corps of Engineers (USACE) field applications. To address these limitations, the design requirements for RECON …

Molecular Dynamics Of High Temperature Hydrogen Attack, Mike Travis Bodden Connor

Theses and Dissertations

High temperature hydrogen attack (HTHA) is a damage mechanism that only affects carbon steel and low alloy material. Most of the data regarding HTHA are experimental-driven. Even though this approach has been successful, there are still much more things that the oil and gas industry does not understand about HTHA. The regions that were considered safe (below the Nelson curves) have experienced catastrophic failure. Our research consists of performing Molecular Dynamics (MD) and the Nudge Elastic Band (NEB) calculation of HTHA to better understand the atomistic behavior of this damage mechanism.

Challenges And Signal Processing Of High Strain Rate Mechanical Testing, Barae Lamdini

Theses and Dissertations

Dynamic testing provides valuable insight into the behavior of materials undergoing fast deformation. During Split-Hopkinson Pressure Bar testing, stress waves are measured using strain gauges as voltage variations that are usually very small. Therefore, an amplifier is required to amplify the data and analyze it. One of the few available amplifiers designed for this purpose is provided by Vishay Micro-Measurements which limits the user’s options when it comes to research or industry. Among the challenges of implementing the Hopkinson technology in the industry are the size and cost of the amplifier. In this work, we propose a novel design of …

Assessment Of Mechanical Engineering Skills: A Synthesis Of Industry And Academic Graduate Level Curriculum Requirements, Francie Baker

Theses and Dissertations

Students who graduate with an advanced degree in mechanical engineering are a diverse group in their path to post-baccalaureate degree attainment. Some students choose to obtain their master’s or Ph.D. post bachelors, but before they enter the workplace. Others enter the workforce and return as full-time students or progress on their advanced degrees while maintaining part- or full-time employment. Current accreditation standards for undergraduate degree programs are part of a changing landscape of standards and professional requirements that have adapted and continue to adapt as programs prepare students to work in professional engineering fields. Advanced degrees do not have the …

Design, Construction, And Characterization Of A Test Stand Used To Test Filter Media, Adam W. Parsons

Theses and Dissertations

Air filters are routinely used to remove various aerosols ranging from radioactive particles to airborne viruses. The overall performance of a filter may be simplified to consider only two main performance characteristics: 1) the efficiency at which particles are removed by the filter, and 2) the filter’s resistance to air flow. Per the DOE Nuclear Air Cleaning Handbook, HEPA filters require a minimum filter efficiency of 99.97% for particles 0.3 micrometers in diameter. Understanding how filters will perform with respect to time and mass loading is essential towards building more robust filters that operate more efficiently and safely. Analyzing the …

Branched Chain Amino Acid Strain State Monitoring With Raman Spectroscopy And Plasmonic Bowtie Nanoantenna Devices For Early Disease Detection, Caroline A. Campbell

Theses and Dissertations

This work centers on the development and the down-selection of nano-manufactured devices to be used in conjunction with Raman spectroscopy for probing a branched chain amino acid. The nano-manufactured devices integrate plasmonic nanoantennas for the purpose of amplifying molecular fingerprints, which are otherwise difficult to detect, through Surface Enhanced Raman Spectroscopy (SERS). Plasmonic nanostructures can be utilized for a variety of biomedical and biochemical applications to detect the characteristic fingerprint provided by Raman Spectroscopy. The nano-manufactured devices create an electric field that amplifies minute perturbations and raises the signal above background noise. This may provide a deeper understanding of signal …

Development And Optimization Of A Low Volume Air-Jet Dry Powder Inhaler (Dpi) Platform For The Delivery Of High Dose Aerosolized Powder To Infants, Connor Howe

Theses and Dissertations

The goal of this research project was to develop an infant air-jet dry powder inhaler (DPI) platform for high-efficiency nose-to-lung (N2L) aerosol administration to infants through optimization of individual system components followed by expansion of the system to higher doses and different formulations using a new approach. Primary challenges associated with aerosol delivery to infants using the N2L route include the extremely narrow extrathoracic airways, short inspiratory times (~0.2 sec), low safe airway pressure (H₂O), and very low volumes of air (~10 mL) available to form the aerosol. The infant air-jet DPI system was comprised of three main …

Modeling The Ballistic Limit Of Fragment Simulating Projectiles Impacting A36 Mild Steel Spaced Armor Configurations, Daniel H. Rios-Estremera

Theses and Dissertations

Terminal ballistics study multivariate behavior and aftermath of projectile and target interactions. Tests and models are often based on monolithic armors, however, layered and spaced armors are common in real world applications. Such configurations add complexities that require research to understand their effects on terminal ballistics. The ballistic limit velocity (V50) represents the speed where armor perforation probability is 50%. It is used for quantitative comparison of protection capabilities for different armors. This research studied the V50 of spaced and layered A36 steel armors against fragment simulating projectiles (FSPs). Four methods for estimating armor V50 were evaluated and compared to …

Uncertainty-Aware Deep Learning For Prediction Of Remaining Useful Life Of Mechanical Systems, Samuel J. Cornelius

Theses and Dissertations

Remaining useful life (RUL) prediction is a problem that researchers in the prognostics and health management (PHM) community have been studying for decades. Both physics-based and data-driven methods have been investigated, and in recent years, deep learning has gained significant attention. When sufficiently large and diverse datasets are available, deep neural networks can achieve state-of-the-art performance in RUL prediction for a variety of systems. However, for end users to trust the results of these models, especially as they are integrated into safety-critical systems, RUL prediction uncertainty must be captured. This work explores an approach for estimating both epistemic and heteroscedastic …

Impact Dynamics Of Surfactant-Laden Droplets On Non-Wettable Coatings, Amir Esmaeili

Theses and Dissertations

Owing to their excellent water repellency, non-wettable (superhydrophobic) coatings have gained tremendous attention in the past couple of decades. Alkyl ketene dimer (AKD), an inexpensive polymer frequently used in paper industry as a sizing agent, has shown potentials to become superhydrophobic. The formation of a porous structure after curing the solidified AKD for an extra-long time (4–6 days) results in superhydrophobicity, i.e., a static contact angle with water of >150° and a roll-off angle of <10°. In this work, a facile and low-cost method was used to turn the surface of AKD superhydrophobic in a very short period of time by briefly treating the coatings, obtained from isothermally heated molten AKD at 40 °C for 3 min, with ethanol. The resulting superhydrophobicity is due to the formation of porous, entangled irregular micro/nano textures that create air cushions on the surface leading to droplet state transition from Wenzel to Cassie. As a proof of concept, the same material was applied to the co-sputtered nickel-tungsten thin films, commonly used in micro/nano-electro-mechanical systems, to improve their hydrophobicity. According to the results, at least 20% increase was observed in the dynamic contact angles of the treated substrates.

In addition, this work presents a detailed high-speed imaging analysis of the influence of the molecular weight, concentration and ionic nature of surfactants on droplet …

Evaluating The Effectiveness Of Aerospace Materials, Vehicle Shape And Astronaut Position At Lowering The Whole Body Effective Dose Equivalent In Deep Space, Daniel K. Bond

Theses and Dissertations

As future crewed, deep space missions are being planned, it is important to assess how spacecraft design can be used to minimize radiation exposure. Collectively with shielding material, vehicle shape and astronaut position must be used to protect astronauts from the two primary sources of space radiation: Galactic Cosmic Rays (GCR) and Solar Particle Events (SPE). GCRs, which are composed of low intensity, highly energetic, and fully ionized stable and meta-stable isotopes, are considered a chronic source of radiation risk to the astronauts. SPEs, which originate from solar coronal mass ejections, are composed mostly of high intensity protons that can …

Resonant Acoustic Wave Assisted Spin-Transfer-Torque Switching Of Nanomagnets, Austin R. Roe

Theses and Dissertations

We studied the possibility of achieving an order of magnitude reduction in the energy dissipation needed to write bits in perpendicular magnetic tunnel junctions (p-MTJs) by simulating the magnetization dynamics under a combination of resonant surface acoustic waves (r-SAW) and spin-transfer-torque (STT). The magnetization dynamics were simulated using the Landau-Lifshitz-Gilbert equation under macrospin assumption with the inclusion of thermal noise. We studied such r-SAW assisted STT switching of nanomagnets for both in-plane elliptical and circular perpendicular magnetic anisotropy (PMA) nanomagnets and show that while thermal noise affects switching probability in in-plane nanomagnets, the PMA nanomagnets are relatively robust to the …

Differential Mobility Classifiers In The Non-Ideal Assembly, Thamir Alsharifi

Theses and Dissertations

The differential mobility classifier (DMC) is one of the core components in electrical mobility particle sizers for sizing sub-micrometer particles. Designing the DMC requires knowledge of the geometrical and constructional imperfection (or tolerance). Studying the effects of geometrical imperfection on the performance of the DMC is necessary to provide manufacturing tolerance and it helps to predict the performance of geometrically imperfect classifiers, as well as providing a calibration curve for the DMC. This thesis was accomplished via studying the cylindrical classifier and the parallel plate classifier. The numerical model was built using the most recent versions of COMSOL Multiphysics^{® …}

Compositional Analysis Of Cerium And Cesium In Rapid Setting Cement As An Immobilization Agent For Nuclear Waste, Riyadh M. Motny

Theses and Dissertations

A feasibility of rapid setting cement (RSC) as an agent of immobilization for certain elements such as fission products or radioactive materials was explored. Cerium (Ce) and cesium (Cs) have been selected as a surrogate for U and/or Pu and fission products, respectively, in this study in three phases. In Phase I, RSC was evaluated for physical properties (e.g., porosity, density, pH values, etc.) using two groups methods—the cement powder at different concentrations of Ce (2 – 10 wt%) with deionized water (DIW) and artificial seawater (ASW). The results showed that the final setting time and compressive strength of RSC …

Development Of Novel Models To Study Deep Brain Effects Of Cortical Transcranial Magnetic Stimulation, Farheen Syeda

Theses and Dissertations

Neurological disorders require varying types and degrees of treatments depending on the symptoms and underlying causes of the disease. Patients suffering from medication-refractory symptoms often undergo further treatment in the form of brain stimulation, e.g. electroconvulsive therapy (ECT), transcranial direct current stimulation (tDCS), deep brain stimulation (DBS), or transcranial magnetic stimulation (TMS). These treatments are popular and have been shown to relieve various symptoms for patients with neurological conditions. However, the underlying effects of the stimulation, and subsequently the causes of symptom-relief, are not very well understood. In particular, TMS is a non-invasive brain stimulation therapy which uses time-varying magnetic …

Experimental Evaluation Of Uranyl Transport Into Mesoporous Silica Gel Using Fluorescence, Brandon M. Dodd

Theses and Dissertations

This research investigated parameters that can affect the use of nanoporous silica gel as a media for accumulating a detectable amount of uranium. The unique fluorescence of the Uranyl (UO₂²⁺) ion was used to evaluate the transport kinetics and accumulation within silica gel in a static fluid and under pressure driven flow. The addition of fluid flow decreased the time constant from on the order of an hour to approximately 2s with a very low fluid velocity of 0.36cm/s. The 0.36cm/s fluid velocity was found to be the critical velocity above which there was no gain in …

Liquid Interaction With Non-Wettable Surfaces Structured With Macroscopic Ridges, Mehran Abolghasemibizaki

Theses and Dissertations

Self-cleaning, anti-corrosion, anti-icing, dropwise-condensation, and drag-reduction are some applications in which superhydrophobic surfaces are implemented. To date, all the studies associated with superhydrophobic surfaces have been dedicated to understanding the liquid interaction with surfaces that are macroscopically smooth. The current study investigates the solid-liquid interaction of such surfaces which are fully decorated with macroscopic ridges (ribbed surfaces). In particular, the drop motion and impact on our newly designed non-wettable ribbed surface have been investigated in this work. Our experimental investigations have shown that liquid drops move faster on the ribbed surfaces due to lower friction induced by such a surface …

Fabricating Superhydrophobic And Superoleophobic Surfaces With Multiscale Roughness Using Airbrush And Electrospray, Karam N. Almilaji

Theses and Dissertations

Examples of superhydrophobic surfaces found in nature such as self-cleaning property of lotus leaf and walking on water ability of water strider have led to an extensive investigation in this area over the past few decades. When a water droplet rests on a textured surface, it may either form a liquid-solid-vapor composite interface by which the liquid droplet partially sits on air pockets or it may wet the surface in which the water replaces the trapped air depending on the surface roughness and the surface chemistry. Super water repellent surfaces have numerous applications in our daily life such as drag …

Modeling Time-Dependent Performance Of Submerged Superhydrophobic Or Slippery Surfaces, Ahmed A. Hemeda

Theses and Dissertations

The goal of this study is to quantify the transient performance of microfabricated superhydrophobic surfaces when used in underwater applications. A mathematical framework is developed and used to predict the stability, longevity, and drag reduction benefits of submerged superhydrophobic surfaces with two- or three-dimensional micro-textures. In addition, a novel design is proposed to improve the drag-reduction benefits of lubricant-infused surfaces, by placing a layer of trapped air underneath the lubricant layer. The new design is referred to as lubricant–infused surfaces with trapped air, and it is designed to eliminate the long-lasting longevity problem of submerged superhydrophobic surfaces. The effectiveness of …

Filter Performance Under Simulated Real-World Conditions, Qiang Wang

Theses and Dissertations

Evaluating the performance of filter media for filtration applications is essential to assure design engineers and users that filter device will deliver promised performance for specific applications under the environmental stress. The study of particle loading characteristics of filter media in the laboratory setting is typically performed under the steady flow conditions, i.e., at the constant particle concentration and flow rate. In reality, filtration products are operated under the situations that the flow rate and mass concentration of particles are varied in time. The success of translating the laboratory data to estimate the performance of filter media in the fields …

Ultrafine Particle Generation And Measurement, Qiaoling Liu

Theses and Dissertations

Ultrafine particles (UFPs) with diameters smaller than 100 nm are omnipresent in ambient air. They are important sources for fine particles produced through the agglomeration and/or vapor condensation. With their unique properties, UFPs have also been manufactured for industrial applications. But, from the toxicological and health perspective, ultrafine particles with high surface-to-volume ratios often have high bio-availability and toxicity. Many recent epidemiologic studies have evidence UFPs are highly relevant to human health and disease. In order to better investigate UFPs, better instrumentation and measurement techniques for UFPs are thus in need. The overall objective of this dissertation is to advance …

Generation And Delivery Of Charged Aerosols To Infant Airways, Landon T. Holbrook

Theses and Dissertations

The administration of pharmaceutical aerosols to infants on mechanical ventilation needs to be improved by increasing the efficiency of delivery devices and creating better ways of evaluating potential therapies. Aerosolized medicines such as surfactants have been administered to ventilated infants with mixed results, but studies have shown improvement in respiratory function with a much lower dose than with liquid instillation through an endotracheal tube (ETT). An aerosolized medicine must be transported through the ventilation tubing and deposit in the lungs to have the desired therapeutic response.

This work has taken a systematic approach to (i) develop new devices for the …

A Study To Evaluate Non-Uniform Phase Maps In Shape Memory Alloys Using Finite Element Method, Naren Motte

Theses and Dissertations

The unique thermo-mechanical behavior of Shape Memory Alloys (SMAs), such as their ability to recover the original shape upon heating or being able to tolerate large deformations without undergoing plastic transformations, makes them a good choice for actuators.

This work studies their application in the aerospace and defense industries where SMA components can serve as release mechanisms for gates of enclosures that have to be deployed remotely. This work provides a novel approach in evaluating the stress and heat induced change of phase in a SMA, in terms of the transformation strain tensor. In particular, the FEA tool

ANSYS has …

Capillarity And Two-Phase Fluid Transport In Media With Fibers Of Dissimilar Properties, Thomas M. Bucher Jr.

Theses and Dissertations

Capillarity is a physical phenomenon that acts as a driving force in the displacement of one fluid by another within a porous medium. This mechanism operates on the micro and nanoscale, and is responsible for countless observable events. This can include applications such as absorption in various hygiene products, self-cleaning surfaces such as water beading up and rolling off a specially-coated windshield, anti-icing, and water management in fuel cells, among many others.

The most significant research into capillarity has occurred within the last century or so. Traditional formulations for fluid absorption include the Lucas–Washburn model for porous media, which is …

Reaction Based Grasp Force Assignment, Mark W. Hunter

Theses and Dissertations

An iterative method is developed by which the contact forces required to apply an arbitrary wrench (six elements of force and moment) to a stably grasped object may be calculated quickly. The assignment of contact forces, given a required object wrench, is accomplished with the use of fuzzy logic. This concept is referred to as the fuzzy logic reactive system (FLRS). The solution is versatile with respect to goals inherent in the rulebase and the input parameters, and is also applicable for an arbitrary number of contacts. The goal presented in this research, to illustrate the concept of the FLRS, …