Machine learning is fast growing field as it can be applied to solve a large amount of problems. One large subsection of machine learning are artificial neural networks (ANN), these work on pattern recognition and can be trained with data sets of known solutions. The objective of this thesis is to discuss the creation of an ANN capable of classifying differences in propylene glycol concentrations, up to 10%. Utilizing a micro pipette thermal sensor (MTS) it is possible to measure the heat propagation of a liquid from a laser pulse. The ANN can then be trained beforehand with simulated data and be tested in real time with temperature data from the MTS. This method could be applied to find the thermal conductivity of unknown fluids and biological samples, such as cells and tissues.

The present study investigates vortex phase separator (VPS) technology as a new approach for a liquid amine CO2 removal system. Experimental results obtained using a 99.99% pure CO2 stream and liquid amine with varying concentrations demonstrate the VPS' ability to decrease CO2 volume at its gas outlet. Operating parameters such as CO2 flow rate, relative humidity (RH), and temperature were systematically varied during experimental procedure, as well as working fluid temperature, volume, and flow rate. The subscale design for a VPS with a 3" inner diameter, 3.5" outer diameter, and 3.63" height removed a maximum of 84% of CO2 from a CO2 stream at 3.7 SCFH flow rate, 14°C temperature, and 82% RH, using 100 mL of 100% amine circulated at 1.52 LPM flow rate. The designed VPS also showed to be effective in removing relative humidity of the CO2 stream by up to 26% for the stated parameters. Regeneration of liquid amine in the VPS system is also proposed to allow for continuous CO2 removal. The results obtained in this work characterize the VPS system for CO2 removal in terms of various operating parameters for the gas (CO2) and liquid (liquid amine) phases, as well as provide initial insights …

This thesis is focused on understanding the correct method to simulate atomistic models to calculate coefficient of diffusion of water through the membrane. It also aims to fix the method previously used in molecular modelling in which the simulation results did not match the experimental results. These membranes will be used in air dehumidification systems. The four types of membranes namely, polyurethane, polyurethane with silica nano particles, polyurethane with silica nano particles and amine surface modifier, and polyurethane with silica nano particles and aniline surface modifier. These membranes were also simulated to understand the effects of temperatures and pressure using molecular dynamics. The software packages used are MAPS 4.3, Avogadro, EMC, OVITO, and LAMMPS. MAPS, Avogadro and EMC were used to model the membrane at an atomistic level while LAMMPS is used to simulate the model generated. OVITO is used to analyze the simulation visually. The movement of water vapor molecules were tracked through the membrane in the simulation and diffusion coefficient was calculated using Mean square displacement equation. To create a realistic model, silica was dispersed in the Polyurethane matrix, simulated under standard atmospheric conditions. These results will help in further optimizing the membrane for air dehumidification. This will …

Several types of research are ongoing throughout the world, to discover economical and reliable techniques to create hydrogen, and propagate the vision of a hydrogen economy. This research examines a COMSOL Multiphysics 5.4 heat transfer model for a hydrogen production system consisting of a retort with two different heat sources, namely a heat tape and an infrared (IR) lamp. The main objective was to compare the two heat sources and find out which one offers a better technique for producing hydrogen by raising the internal center core temperature of the retort from ambient to the highest temperature, preferably 700℃, within the shortest time possible and using less power consumption in attaining the targeted temperature. Through this study, it was established that the IR lamp could potentially help with energy savings by using just 4 kWh to reach the targeted temperature within an hour.

This work investigated a novel vapor chamber for efficient heat spreading and heat removal. A vapor chamber acting as a heat spreader enables for more uniform temperature distribution along the surface of the device being cooled. First, a vapor chamber was studied and compared with the traditional copper heat spreader. The thickness of vapor chamber was kept 1.35 mm which was considered to be ultra-thin vapor chamber. Then, a new geometrical model having graphite foam in vapor space was proposed where the graphite foam material was incorporated in vapor space as square cubes. The effects of incorporating graphite foam in vapor space were compared to the vapor chamber without the embedded graphite foam to investigate the heat transfer performance improvements of vapor chamber by the high thermal conductivity graphite foam. Finally, the effects of various vapor chamber thicknesses were studied through numerical simulations. It was found that thinner vapor chamber (1.35 mm thickness) had better heat transfer performance than thicker vapor chamber (5 mm thickness) because of the extreme high effective thermal conductivities of ultra-thin vapor chamber. Furthermore, the effect of graphite foam on thermal performance improvement was very minor for ultra-thin vapor chamber, but significant for thick vapor chamber. …

Fiber-metal laminates (FML) are the advanced materials that are developed to improve the high performance of lightweight structures that are rapidly becoming a superior substitute for metal structures. The reasons behind their emerging usage are the mechanical properties without a compromise in weight other than the traditional metals. The bond remains a concern. This thesis reviews the effect of pre-treatments, say heat, P2 etch and laser treatments on the substrate which modifies the surface composition/roughness to impact the bond strength. The constituents that make up the FMLs in our present study are the Aluminum 2024 alloy as the substrate and the carbon fiber prepregs are the fibers. These composite samples are manufactured in a compression molding process after each pre-treatment and are then subjected to different tests to investigate its properties in tension, compression, flexural and lap shear strength. The results indicate that heat treatment adversely affects properties of the metal and the joint while laser treatments provide the best bond and joint strength.

Functionally graded materials (FGMs) are inhomogeneous materials in which the material properties vary with respect to space. Research has been done by scientific community in developing techniques like photothermal radiometry (PTR) to measure the thermal conductivity and volumetric heat capacity of FGMs. One of the problems involved in the technique is to solve the inverse problem, i.e., estimating the thermal properties after the frequency scan has been obtained. The present work involves finding the unknown thermal conductivity and volumetric heat capacity of the FGMs by using finite volume method. By taking the flux entering the sample as periodic and solving the discretized 1-D thermal wave field equation at a frequency domain, one can obtain the complex temperatures at the surface of the sample for each frequency. These complex temperatures when solved for a range of frequencies gives the phase vs frequency scan which can then be compared to original frequency scan obtained from the PTR experiment by using a residual function. Brute force and gradient descent optimization methods have been implemented to estimate the unknown thermal conductivity and volumetric specific heat of the FGMs through minimization of the residual function. In general, the spatial composition profile of the FGMs can …

Knee osteoarthritis (KOA) is the primary cause of chronic immobility in populations over the age of 65. It is a joint degenerative disease in which the articular cartilage in the knee joint wears down over time, leading to symptoms of pain, instability, joint stiffness, and misalignment of the lower extremities. Without intervention, these symptoms gradually worsen over time, decreasing the overall knee range of motion (ROM) and ability to walk. Current clinical interventions include offloading braces, which mechanically realign the lower extremities to alleviate the pain experienced in the medial compartment of the knee joint. Though these braces have proven effective in pain management, studies have shown a significant decrease in knee ROM while using the brace. Concurrently, development of active exoskeletons for rehabilitative gait has increased within recent years in efforts to provide patients with a more effective intervention for dealing with KOA. Though some developed exoskeletons are promising in their efficacy of fostering gait therapy, these devices are heavy, tethered, difficult to control, unavailable to patients, or costly due to the number of complicated components used to manufacture the device. However, the idea that an active component can improve gait therapy for patients motivates this study. This study …

The goal of this research is to measure viscosity via the analysis of amplitude response of a piezo driven vibrating cantilevers partially immersed in a viscous medium. As a driving frequency is applied to a piezoceramic material, the external forces acting on the system will affect its maximum amplitude. This thesis applies this principle through experimental and analytical analyses of the proportional relationship between viscosity and the amplitude response of the first natural frequency mode of the sinusoidal vibration. Currently, the few cantilever-based viscometer designs that exist employ resonant frequency response as the parameter by which the viscosity is correlated. The proposed piezoelectric viscometer employs amplitude response in lieu of resonant frequency response. The goal of this aspect of the research was to provide data confirming amplitude response as a viable method for determining viscosity. A miniature piezoelectric plate was mounted to a small stainless-steel cantilever beam. The tip of the cantilever was immersed within various fluid test samples. The cantilever was then swept through a range of frequencies in which the first frequency mode resided. The operating principle being as the viscosity of the fluid increases the amplitude response of cantilever vibration will decrease relatively. What was found was …

In several areas around the world, clean water is a precious asset that at anytime, and mainly due to circumstances of weather and climate, can become scarce. Mainly in the dry and remote places, people suffer with lack of water. A solution for this suffering can be a water desalination system, which makes water potable and usable for industry. That solution inherently, brings the problem of power requirement, which is sometimes arduous to accomplish in such remote areas of difficult access and long distances to overcome to build the infrastructure required to operate an electric power plant. Texas and the USA also face this scenario for many regions, for which the government has been creating some programs and driving forward incentives, looking for solutions to support water desalination. Water desalination has future applications for municipalities water-consuming or for arid and remote regions, as well as for industries that rely on heavy water usage, such as natural gas drilling operations, for which millions of gallons are trucked overland to the site and also hauled away afterwards, when the waste water produced must be treated. This thesis created the concept of autonomy for water desalination plants replacing the actual power supply from …

This thesis project investigates, analyzes, designs, simulates, constructs and tests a dual-axis solar tracker system to track the sun and concentrates the heat of the sunlight, using a Fresnel lens, into a small area, which is above of an evaporator, to increase the temperature of the seawater to convert it into freshwater. The dual-axis solar tracker was designed with the main objectives that the structure was portable, dismountable, lightweight, low cost, corrosion resistant, wires inside pipes, accurate, small size, follow the sun automatically, off-grid (electrical), use green energy (solar powered), and has an empty area right below of the lens. First, a 500 mm diameter flat Fresnel lens was selected and simulated based on an algorithmic method achieved by a previous PhD student at UNT using MATLAB®, to give the optimization lens dimensions. The lens profile was drawn with AutoCAD®, then output profile lens was simulated in COMSOL Multiphysics®. The objective was to provide the high efficiency, optimum and high precision of the focal rays and heat to the receiver of the evaporator. A novel dual-axis solar tracker system was then designed that is portable, dismountable, lightweight and corrosion resistant. The solar tracker tracks the sun in two axis of …

The interest toward Mars exploration has been considerably increasing due to also the successful deployment of the Perseverance rover and the continuous tests developed by SpaceX's launch vehicle, Starship. While the Mars 2020 mission is currently in progress, the first controlled flight on another planet have been proven in April 2021 with the vertical take-off and landing of the Ingenuity rotorcraft on Mars. In addition, the rotorcraft Dragonfly is expected to achieve the same endeavor in Titan, the largest moon of Saturn, by 2036. Continuous efforts have been oriented toward the development of new technologies and aircraft configurations to improve the performance of current proposed designs to achieve powered flight in different planetary bodies. This thesis work is a preliminary study to develop a comprehensive analysis over the generation of optimum airfoil geometries to achieve vertical flight in environments where low Reynolds numbers and Mach number equal to 0.2 and 0.5.

Although the capability of computational fluid dynamics (CFD) in modeling ship hydrodynamics is well explored in many studies, they still have two main limitations. First, those studies ignore the effect of non-uniform shear current which exists in realistic situation. Second, the focus of most studies was laid more on the seakeeping/maneuvering performance and less attention was paid to survivability of ships due to extreme ship response events in waves, which are considered rare events but influential. In this thesis, we explore the capability of CFD in those two areas. In the first part of the thesis, the hydrodynamic performance of KCS in the presence of a non-uniform shear current is investigated for the first time using high-fidelity CFD simulations. Various shear current conditions with different directions were considered and results were compared with the ones with no shear current. The second part of the thesis focuses on study of rare events of ship responses by development of extreme response conditioning techniques to design the wave trail. Two conditioned techniques based on Gaussian and non-Gaussian processes are considered.

In this thesis, friction stir channeling (FSC) and its process parameters influence on geometry, surface quality and productivity are explored. The probe of the friction stir processing (FSP) tool used to perform these tests was a modified submerged bobbin tool made of MP 159 Co-Ni alloy. The body was made from H13 tool steel. To find the optimal channel conditions for a targeted range of process parameters, multiple 6061 aluminum samples were prepared with a U shape guide to test the effects of different spindle speeds and feed rates. Using a gantry-type computer numerical control (CNC) friction stir welding (FSW) machine, the aluminum coupons were subjected to calibration experiments, force control tests, and an increased production rate to test these effects. It was found through experimentation that the programmed feed rates, spindle speeds and forces produced by the machine had an impact on the channel geometry. It was determined from the force-controlled setup that 8.46 mm/s at 750 RPM was the best combination of results for the four conditions tested on a CNC friction stir processing-machine. It was then tested at 10.58 mm/s at 800 RPM, which had comparable results with the best combination of input parameters from the force-controlled …

This thesis details the creation and application of a generalized process plan for the hybrid manufacturing of AISI 316L stainless steel, using direct energy deposition (DED) and ball-nose end-mill machining, that includes the inspection and measurement of objects created by that hybrid manufacturing process plan. The proposed process plan progresses through the selection of substrate thickness, single-track, multi-track, and multi-layer depositions, then on to machining processing. A manufacturers' recommended set and range of DED parameters were used to create a designed experiment that aided in the analysis of objects created in each of the DED process planning steps; those objects were then machined in the same enclosure using a set of machining parameters screened from industry recommendations for ball-nose milling of stainless steel, after which measurements were taken for surface roughness, some material characteristics, and for tool deterioration. The results, analyses, and discussions collected herein show that the proposed process plan can provide models for geometrical outputs for each step in the plan, some improvements in substrate stability, surface roughness, tool deterioration, and material porosity due to voids. Current research in hybrid manufacturing does not show generalized process planning influences. The process plan as demonstrated by the work in this …

In order to better understand the changes occurring in the internal environment of the pyrolysis process a method of monitoring the internal environment in real time is the key objective of this study. To accomplish this objective four tasks were laid out in order to develop an effective way of monitoring the changes in gases present as pyrolysis is occurring as well as in material activation processing. For all processing the self-activation process was used which combines pyrolysis and thermal activation into a single step process. In the first task 10 hard wood species were activated and the resulting properties were compared to see the impact of wood species on the resulting carbon structures. In order to understand the impact of gas concentration on the resulting carbons the second task developed a gas sensor array which effectiveness was corroborated using GC-MS and then comparisons of the changes in the resulting were made. For the third task the gas sensor array was used to analyze the production of CO2 gas and a triple Gaussian model was developed to model the changes in gas production throughout processing. H2 gas production was modeled in the fourth task using the same Gaussian model as …

Recently, 3D printing has received increasing attention for the fabrication and assembly of electrodes for batteries due to the freedom of creating structures in any shape or size, porosity, flexibility, stretchability, and chemistry. Particularly, zinc ion batteries (ZIBs) are favored due to high safety, cheap materials cost, and high volumetric capacity (5,849 mAh/cm3), however, rapid evaporation of Zn due to low melting temperature has limited its 3D printability via conventional laser-based additive manufacturing technique. Here, we develop a printable ink for the fabrication of flexible and 3D printed Zn anode with varied surface areas using the direct ink writing (DIW) method. Our 3D printed porous and high surface area Zn anode structures effectively suppressed the dendrite growth while providing high Zn ion diffusion towards the cathode to significantly enhance the performance of ZIB. By varying filament distancing and path, we 3D printed zinc anode structures with different active surface areas, surface area to volume ratio, porosity, flexible and multiple layer structures that can be incorporated on any device. Carbon in the composite improved conductivity, and mechanical stability of 3D printed zinc anode. Our 3D printed composite anodes allowed flexible designing of batteries surpassing conventional battery designs such as coin cells …

Lignocellulose is the most abundant biopolymer on earth and offers excellent potential for sustainable manufacturing. Because lignocellulose is structurally complex and resistant to decomposition, innovative degradation strategies are necessary to unlock its value. In this dissertation, a green manufacturing process through enzyme-triggered self-cultured bacteria retting for lignocellulosic fiber was developed and investigated. The mechanism of the lignocellulosic fiber retting at a controlled degradation strategy was studied. This enzymatic degradation strategy utilizes a small amount of enzyme to trigger a large aggregation of specific bacteria to obtain clean fibers. Industrial hemp (Cannabis sativa L.) fiber was successfully retted with this strategy. The degradation of pectin was proved through an environmental scanning electron microscope and reducing sugar analysis. The bacterial successions were identified by 16S rRNA gene metagenomic sequencing. The results showed that Bacillaceae dominated the hemp retting conditions containing 1% pectinase, suggesting that pectinase can manipulate bacterial community succession by changing the nutrients available to bacteria through the degradation of pectin. This degradation strategy has 20-25% less environmental impact than the thermochemical degradation strategy, resulting in better fiber consistency and much shorter processing time (3-5 days) than the traditional water degradation strategy. The study on the degradation of lignin-rich lignocellulose also …

This thesis describes the experimental and numerical investigation of a novel cold-formed steel 48ft and 54ft long span truss. The truss we designed was to be used as the roofs of large buildings, such as warehouses, hangars, sports arenas. The investigation includes both experimental and numerical testing, the experimental testing of the truss under uniform loads (increasing loads) to determine its deflection and load carrying capacity. The numerical test included developing a finite element model of the truss in SolidWorks and using a finite element model of the truss in ABAQUS to simulate the experimental tests. The findings of this study can be used to improve the design of cold-formed steel long span trusses. The study also provides valuable information for future studies on the modeling of trusses with different cold-formed steel members and the behavior of trusses under load.

Motivated by previous relevant research on phononics including both active and passive phononics, the interest of faster turnability and more functions of the active phononics of further study led to this proposing research topic: magnetic field tunable active functional phononics. The first design of magnetic field tunable reciprocal--non-reciprocal transmission acoustic device was established, material was characterized, and numerical simulation has been performed. The simulation results show clear T-symmetric breaking non-reciprocity due to energy level splitting effect with Doppler effect – an acoustic Zeeman effect. Inspired by this preliminary work, further experiments were planned to demonstrate this effective Zeeman effect in phononics and effectively charged phonons in water based ferro-fluid. The objectives of this work as the next series of tasks were to illustrate acoustic Zeeman effect and acoustic Landau levels in various strength of magnetic field to investigate a design non-reciprocal sound device with magnetic field switching, which could be controlled on the amount of non-reciprocity with the strength of magnetic field. Once this new field first discovered by the proposed study tasks, more active tunable magnetic field phononics devices could be designed and exemplified in terms of both simulations and experiments. Faster and more controllable active phononic devices could …