Engineering Commons^™

Applications Of Machine Learning In Nuclear Imaging And Radiation Detection, Shaikat Mahmood Galib

Doctoral Dissertations

"The main focus of this work is to use machine learning and data mining techniques to address some challenging problems that arise from nuclear data. Specifically, two problem areas are discussed: nuclear imaging and radiation detection. The techniques to approach these problems are primarily based on a variant of Artificial Neural Network (ANN) called Convolutional Neural Network (CNN), which is one of the most popular forms of 'deep learning' technique.

The first problem is about interpreting and analyzing 3D medical radiation images automatically. A method is developed to identify and quantify deformable image registration (DIR) errors from lung CT scans …

Mass Spectrometry Analysis Of Contaminants Of Emerging Concern: Nanoparticles, Algal Toxins, And Cyanotoxins In Natural Waters And Their Potential Health Impacts, Ariel R. Donovan

Doctoral Dissertations

“The analysis of contaminants of emerging concern is critical to protecting environmental health. In the presented dissertation, two groups of contaminants of emerging concern were assessed using mass spectrometry methods: nanoparticles and algal and cyanotoxins.

Analysis of metal oxide nanoparticles in environmental matrices has been a challenging issue, as most traditional methods require complicated sample preparation methods or that can alter or destroy the nanoparticles in the system. Single particle inductively coupled plasma mass spectrometry (SP-ICP-MS) methods were used to detect metal oxide nanoparticles in surface waters and their removal through drinking water treatment simulations while retaining all information regarding …

Ferrite Characterization Techniques & Particle Simulations For Semiconductor Devices, Nicholas Erickson

Doctoral Dissertations

"This dissertation is divided into three papers, covering two major topics. The first topic, techniques for ferrite characterization, is discussed over the course of two papers. The second topic, particle simulations for semiconductor devices, is discussed in the last paper. In the first paper, the method for extracting permeability from ferrite materials is discussed for the Keysight 16454A permeability extraction fixture, where the ferrite material to be characterized is assumed to be homogeneous. Then the method is updated to account for layered materials. The updated method is verified through full-wave simulations. In the second paper, a planar printed circuit board …

Plenum-To-Plenum Heat Transfer Characteristics Under Natural Circulation In A Scaled-Down Prismatic Modular Reactor, Salman Mohammed Alshehri

Doctoral Dissertations

“Gas-cooled reactor (GCR) is being developed under the Next Generation Nuclear Plant Program (NGNP) in nuclear engineering studies. As the world searches for an energy source with high energy density, clean, abundant, and storable nature to avoid global warming issues, GCR seems to be a promising solution, particularly the possibility of producing hydrogen. Studying and developing the safety analysis and GCR technologies are required for the optimum design and safety of GCR system. Multiphase Reactors Engineering and Applications Laboratory (mReal) at Missouri University of Science and Technology (S&T) has developed a natural convection heat transfer test facility with one riser …

Estimating Electromagnetic Emissions From A Site Installation With Multiple Racks Of Server Equipment, Ze Sun

Masters Theses

“There are hundreds, sometimes even thousands, of servers working simultaneously inside a data center. Their radiation can be a problem and cause EMI issues. However, it is not feasible to perform full-wave simulation of these racks because of the large electric size of the model. In this thesis, an algorithm is proposed to predict the emission form rack array. The equivalent dipole source is extracted from EMI measurement data of a single rack and used as the radiation source in the multiple rack model. The coupling between racks cannot be ignored, but through the simulation, it is also found that …

Influence Of Pumping Parameters On The Freeze-Thaw And Scaling Resistance Of Highly Workable Concrete, Alexandra Nicole Wehar

Masters Theses

“Over the past 60 years, pumping concrete has gained popularity due to the economic and technical benefits that typically accompanies it. However, boom configuration and flow rate can adversely affect freeze-thaw and scaling resistance of concrete due to the effects of pressure on the air-void system. Therefore, the objective of this research is to assess the influence of different pumping parameters on the durability of hardened self-consolidating concrete. Self-consolidating, flowable, and conventional concrete mixtures were tested during large scale pumping experiments positioning the pump boom in an “A” and a flat shape as well as using different pumping speeds. In …

Reliability Analysis For Systems With Outsourced Components, Zhengwei Hu

Doctoral Dissertations

"The current business model for many industrial firms is to function as system integrators, depending on numerous outsourced components from outside component suppliers. This practice has resulted in tremendous cost savings; it makes system reliability analysis, however, more challenging due to the limited component information available to system designers. The component information is often proprietary to component suppliers. Motivated by the need of system reliability prediction with outsourced components, this work aims to explore feasible ways to accurately predict the system reliability during the system design stage. Four methods are proposed. The first method reconstructs component reliability functions using limited …

Biofuel Supply Chain Restructuring -- An Economic Viability And Environmental Sustainability Investigation For Enhancing Second Generation Biofuel Adoption, Rajkamal Kesharwani

Doctoral Dissertations

"Biofuel is a promising clean alternative to fossil fuels. Currently, first generation biofuels are commercially produced by using corn grain as biomass feedstock. However, the use of edible matter of crops, may lead to a competition between food and fuel. Therefore, there is a significant push in both industry and academia to commercialize second generation biofuel manufacturing technology, which uses non-edible matter from crops. Most research focuses on individual manufacturing processes for producing second generation biofuel, but the economic and environmental impacts of a large-scale adoption of second generation biofuel manufacturing have been less widely reported.

This work investigates the …

Multiphysics Prediction Model Of Microwave Curing For Thick Polymer Composites, Siva Dasari

Masters Theses

"Microwave curing technologies have many advantages over the traditional thermal curing methods for the manufacturing of fiber reinforced polymers, especially the processing speed and energy efficiency. Energy can be instantaneously transferred through applied electromagnetic fields and heat is generated based on dipolar rotational interactions. Microwave curing processes have been used for glass fiber composites but there are significant challenges associated with microwave curing of carbon fiber composites. Efficient heating may be difficult due to high dielectric loss associated with carbon fibers. Laminate quality will be highly dependent on the uniformity of the electromagnetic field in the material. In this work, …

Nanoscale Solidification Of Metals By Atomistic Simulations: From Nucleation To Nanostructural Evolution, Avik Mahata

Doctoral Dissertations

"Homogeneous nucleation during solidification in Al (fcc), Fe (bcc) and Mg (hcp) is studied by million-atom molecular dynamics (MD) utilizing the second nearest neighbor modified embedded atom method (2NN-MEAM) potentials. Spontaneous homogenous nucleation from the melt was produced without any influence of pressure, free surface effects and impurities. We also study the effect on the simulation size on homogenous nucleation and the heterogeneity in homogenous nucleation. The heterogeneity in homogenous nucleation originates from the twins, grain boundaries and short range order in the liquid during the initial stages of solidification.

To study the solid-liquid coexistence in binary Al alloys, interatomic …

Volumetric Error Compensation For Industrial Robots And Machine Tools, Le Ma

Doctoral Dissertations

“A more efficient and increasingly popular volumetric error compensation method for machine tools is to compute compensation tables in axis space with tool tip volumetric measurements. However, machine tools have high-order geometric errors and some workspace is not reachable by measurement devices, the compensation method suffers a curve-fitting challenge, overfitting measurements in measured space and losing accuracy around and out of the measured space. Paper I presents a novel method that aims to uniformly interpolate and extrapolate the compensation tables throughout the entire workspace. By using a uniform constraint to bound the tool tip error slopes, an optimal model with …

Use Of Wicking Geotextile To Dehydrate Road Embankments, Chuang Lin

Doctoral Dissertations

“Excess water within a pavement structure is the major cause of pavement deteriorations. A roadway is often constructed with soils compacted at the optimum water contents to achieve the best performance. After construction, the soil water content variation is controlled by the ambient environment. The base course aggregate is very sensitive to water content variations. Unfortunately, conventional drainage system can only drain gravity water, but not capillary water, and it cannot work under unsaturated conditions. Consequently, no matter how well the road is constructed, the water content is expected to increase with time and the excess water will inevitably accelerate …

Development Of A Switchable Radioisotope Generator, Kyle Mitchell Paaren

Doctoral Dissertations

The Switchable Radioisotope Generator utilizes alpha-induced reactions to produce a combination of photons, neutrons, and protons with varying fluxes dependent on target materials and source geometry. The activity/strength of the secondary radiation is further controlled by manipulating the number of alpha particles that can interact with the target material(s). Analytical equations were solved to confirm secondary radiation production from target materials using average cross sections from TENDL data. TENDL and JENDL data was confirmed by analytically solving for the total alpha-induced cross sections. This information was used to produce the provisional and utility Patent No: US20190013109A1. TENDL data was then …

Development Of Castrip Dual Phase Steel, Brenton Allen Hrebec

Masters Theses

“Thermomechanical processing necessary to produce DP 980 steel using CASTRIP hot band was investigated. The resultant steel has an ultimate tensile strength of 1038 MPa, yield strength of 744 MPa, and total elongation of 8.6%. These mechanical properties were achieved by batch annealing the hot band at 649°C for 48 hours and cold rolling to a 20% reduction. The steel was continuously annealed to simulate a galvanization cycle with an intercritical temperature of 810°C. The possibility of improving the texture of the steel by warm rolling under dynamic strain aging conditions was investigated. Dynamic strain aging in the CASTRIP hot …

Performance Of One-Part And Two-Part Class C Fly Ash-Based Alkali Activated Mortars, Cedric Chani Kashosi

Masters Theses

“Seeking an eco-friendly concrete, researchers have conducted studies to fully replace ordinary Portland cement (OPC) with fly ash (FA) producing alkali-activated concrete (AAC). Results showed better performance of AAC in terms of high early compressive strength, and durability compared to conventional concrete. However, much is still unknown about the behavior of AAC. From the type of materials used, the curing procedure, and long-term strength development of these binders; a thorough investigation is needed in order to fill the existing gap from previous studies and thus make a step forward to the safely use of AAC in the construction industry. The …

Laser Machining Countersinks In Carbon Fiber Reinforced Polymer, Leon James Neely Hill

Masters Theses

“Laser machining countersinks with a frequency doubled Q-switched diode pumped Nd:YAG laser is demonstrated. Tests were conducted in 0.100" thick IM7 prepreg CFRP with [0,90]3S orientation. The HAZ is minimized to avoid stress concentrations in the epoxy matrix. A chamber and filtration system was designed and built to contain the byproducts produced in the machining process. The variables investigated are the number of repetitions in the offset path, the plunge rate, and the line energy. The research was performed over one baseline study, one parameter space exercise, two full factorial experiments, and one repeatability study. Assessment was done under an …

The Effect Of Cell Size And Surface Roughness On The Compressive Properties Of Abs Lattice Structures Fabricated By Fused Deposition Modeling, Leah Hope Mason

Masters Theses

"Postprocessing is an important step in many manufacturing methods, but it is especially important for additive manufacturing. Researchers looking to improve the surface roughness of acrylonitrile butadiene styrene (ABS) parts fabricated by fused deposition modeling (FDM) have determined that acetone smoothing not only achieves improved surface roughness but increases compressive strength as well. This could be very beneficial to lattice structures, which are known for already having an excellent strength to weight ratio. If the compressive strength of ABS lattice structures could be improved even further using acetone smoothing, it could expand the applications for plastic lattice structures and improve …

Plasmonic Metamaterial For Structural Color Printing And Spontaneous Emission Control, Wei Wang

Doctoral Dissertations

”Plasmon polaritons or plasmons are a collective oscillation movement of free electrons in metal at optical frequencies. The frequency-dependent complex dielectric function makes the metal property at optical frequencies behave totally different with that at other spectral ranges with lower frequency such as infrared and microwaves. This novel property makes the so called plasmonics or nanoplasmonics a rapid growing research field over the past few years. Many innovative concepts and applications have been developed such as perfect absorber, structural color printing, and quantum emitter spontaneous emission enhancement.

In this dissertation two of the most important applications will be addressed. The …

Build Strategy Investigation Of Ti-6al-4v Produced Via A Hybrid Additive Manufacturing Process, Lei Yan

Doctoral Dissertations

“Till now, laser metal deposition (LMD) has been developed with the capability of near-net shape high-performance metal parts fabrication, especially complicated titanium alloys, nickel alloys, and aluminum alloys. However, LMD processed parts usually do not meet end-use requirements without post treatments. In-process part quality inspection and inner features machining are impossible within a single LMD process. Hybrid additive manufacturing (HAM), which integrates additive and subtractive manufacturing in one process, has been proposed to increase the feasibility of complex parts fabrication. This dissertation aims to improve the applications of Ti-6Al-4V parts fabricated via a HAM technique. The first research topic is …

Numerical Modeling Study Of A Neutron Depth Profiling (Ndp) System For The Missouri S&T Reactor, Mubarak Mohammed Albarqi

Doctoral Dissertations

”For decades, Neutron Depth Profiling has been used for the non-destructive analysis and quantification of boron in electronic materials and lithium in lithium ion batteries. NDP is one of the few non-destructive analytical techniques capable of measuring the depth profiles of light elements to depths of several microns with nanometer spatial resolution. The technique, however, is applicable only to a handful of light elements with large neutron absorption cross sections. This work discusses the possibility of coupling Particle Induced X-ray Emission spectroscopy with Neutron Depth Profiling to yield additional information about the depth profiles of other elements within a material. …

Design And Characterization Of A Strong Positron Source At The Mstr Beam Port, Raed Atiah Alsulami

Doctoral Dissertations

“For many years, slow positron sources have found uses in diverse fields including medical physics, nuclear physics, biology, surface science, exotic atom research and space science. The purpose of this work is to design and optimize a reactor-based positron source at the Missouri University of Science and Technology Reactor (MSTR) beam port and quantify its intensity. Monte Carlo simulations using the MCNP6 code were used to model the positron production and moderation processes at the MSTR beam port. The thermal neutron flux at the beam port was determined experimentally and used in the source definition of the radiation transport simulations. …

Scaleable Nanomanufacturing Of Metasurfaces Using Microsphere Photolithography, Chuang Qu

Doctoral Dissertations

“The cost-effective manufacturing of metasurfaces over large areas is a critical issue that limits their implementations. Microsphere photolithography (MPL) uses a scalable self-assembled microsphere array as an optical element to focus collimated light to nanoscale photonic jets in a photoresist layer. This dissertation investigates the fabrication capabilities, process control, and potential applications of MPL. First, the MPL concept is applied to the fabrication of metasurfaces with engineered IR absorption (e.g. perfect absorption with multiband/broadband and wavelength/polarization dependences). Improving the patterning of the photoresist requires a fundamental understanding the photochemical photonic jet interactions. The dissertation presents a model of the MPL …

Unmanned Aerial And Traversing Vehicle -- A Mobile Platform For Bridge Inspections, Clayton A. Fritsche

Masters Theses

“Unmanned aerial vehicles (UAVs), also known as drones, have been rapidly growing in popularity since their creation. This study aimed to create a robotic platform used to assist in the inspection process of the nation’s aging and deteriorating bridges. To this end, a multimodal inspection robot that utilized both flying and driving technologies, was designed, analyzed, and tested for aerial, traversing, and their transitional operability. The design, herein referred to as the “BridgeBot”, was evaluated both computationally and experimentally. A finite element model of the BridgeBot was established and analyzed under static loading scenarios to help determine stress distributions and …

Design And Performance Of Fiber-Reinforced Concrete With Adapted Rheology For Construction And Repair Of Bridge Structures, Ahmed Abdelrazik

Doctoral Dissertations

“The objective of this document is to design high-performance fiber-reinforced self-consolidating concrete (FR-SCC) for infrastructure repair and fiber-reinforced super-workable concrete (FR-SWC) for bridge construction. The investigated fibers included propylene synthetic fibers, hooked steel fibers, double and triple hooked steel fibers, hybrid crimped steel fiber and polypropylene multifilament fibers, and micro-macro steel fibers. The fiber volume varied between 0 and 0.75%. An expansive agent (EA) was incorporated to compensate for shrinkage and induce compression in the concrete at early age. Two types of EA (G and K) were employed at 0 to 8%, by mass of binder. The investigated FRSCC and …

Development Of Functional Ionic Liquids For Separation And Recovery Of Rare Earth Elements, Mostafa Khodakarami

Doctoral Dissertations

“This research focused on the design and synthesis of task-specific ionic liquids for enhanced extraction and separation of rare earth elements (REEs). Two novel ammonium-based functional ionic liquids (FILs) with oxygen donating groups: trioctyl(2-ethoxy-2-oxoethyl)ammonium dihexyl diglycolamate, [OcGBOEt][DHDGA], and tricaprylmethylammonium dihexyl diglycolamate, [A336][DHDGA] were synthesized and tested for the recovery and separation of selected REEs from aqueous solutions. Functionalities with different denticities were incorporated into both anionic and cationic parts of ionic liquids, which are solely composed of incinerable atoms including C, H, O, and N. The structural, physical, and chemical properties of the synthesized FILs were studied using nuclear magnetic …

Atomistic Simulations Of Deformation In Metallic Nanolayered Composites, Sixie Huang

Doctoral Dissertations

"The mechanical behavior of Metallic Nanolayered Composites (MNCs) is governed by their underlying microstructure. In this dissertation, the roles of the interlayer spacing (grain size, d) and the intralayer biphase spacing (layer thickness, h) on mechanical response of Cu/Nb MNCs are examined by Molecular Dynamics (MD) simulations. The study of the strength of MNCs show that small changes in both d and h play a profound role in the relative plastic contributions from grain boundary sliding and dislocation glide. The interplay of d and h leads to a very broad transition region from grain boundary sliding dominated flow, where the …

Development Of Test Methods For Characterizing Extrudability Of Cement-Based Materials For Use In 3d Printing, Jonathan Thomas Kuchem

Masters Theses

"3D printing is the process of creating three-dimensional objects using an automated additive manufacturing process. The 3D printing process has been used with materials such as metals and polymers, but application with cement based materials for the construction industry has yet to be developed. In this research, two main problems were investigated for printing cement based composite materials: extrudability and tensile reinforcement. Fiber-reinforced concrete (FRC) was studied as an internal reinforcing system to increase tensile/flexural strength. First, FRC was studied to investigate mechanical properties and use of fibers from waste tires as an environmentally friendly option. A reference mixture with …

Characterization Of A Green Electric Solid Propellant For Electric Propulsion, Matthew Scott Glascock

Doctoral Dissertations

"Electric solid propellants are advanced solid chemical rocket propellants that can be controlled (ignited, throttled and extinguished) through the application and removal of an electric current. These propellants are also being considered for use in ablative pulsed plasma thruster and multimode systems. In this work, the behavior and performance of a novel green electric solid propellant operating in an electrothermal ablation-fed pulsed plasma thruster was investigated. Using an inverted pendulum micro-Newton thrust stand, the impulse bit and specific impulse of the device using the electric solid propellant were measured for short-duration and long-duration runs to end-of-life, at energy levels of …

Modeling Strategies For Estimating And Suppressing Electromagnetic Interference And Improving Power Integrity, Tamar Makharashvili

Doctoral Dissertations

"Decoupling capacitors are used to suppress high-frequency noise in power distribution networks. The inductance associated with a mounted decoupling capacitor can vary by 26% depending on characteristics of the printed circuit board. Here, simple and accurate inductance models of 2- and 8-terminal capacitors including connections to the power and return plane are developed. Circuit models of the capacitors and layout are created using the partial equivalent element circuit method which provide options for circuit-level simulations as well as analytic estimation of inductance. The circuit solution matches results from the full-wave simulation model within 9% for the 8-terminal capacitor and within …

Evaluation Of Naturally Occurring And Anthropogenic Contamination In Missouri Streams, Christina Jane Sehrt

Masters Theses

"The goal of this study is to observe the values and variability of water quality parameters and benthic macroinvertebrates in watersheds with very little anthropogenic impact and to compare these values with those acquired in watersheds with more anthropogenic impact. The following five HUC 12-digit watersheds had very little anthropogenic impact and were considered "pristine": Rogers Creek, Mill Creek, Middle West Fork-Black River, Bee Fork, and Ottery Creek. Five largely urban sub-basins were also considered; these basins are: Grand Glaize Creek, Glaize Creek, Sugar Creek, Hominy Creek, and Grindstone Creek. For each watershed, both water quality parameters and benthic macroinvertebrates …