Engineering Commons^™

Three Segment Adaptive Power Electronic Compensator For Non-Periodic Currents, Amin Ghaderi

Theses and Dissertations

In this dissertation, a new technique is proposed for the compensation of nonperiodic load current. The method provides control references for three co-located devices, each corresponding to one moving calculation window and one decomposed part of the compensated current. They are slow compensator with high power rating, large calculation window, and low switching frequency; fast compensator with lower power rating, shorter calculation window, and higher switching frequency; and the reactive compensator which is an ordinary static VAR compensator (SVC). To improve the flexibility of the technique, a fuzzy based adaptive window is proposed for the slow compensator to find the …

Wideband Low Side Lobe Aperture Coupled Patch Phased Array Antennas, Dhruva Poduval

Theses and Dissertations

Low profile printed antenna arrays with wide bandwidth, high gain, and low Side Lobe Level (SLL) are in great demand for current and future commercial and military communication systems and radar. Aperture coupled patch antennas have been proposed to obtain wide impedance bandwidths in the past. Aperture coupling is preferred particularly for phased arrays because of their advantage of integration to other active devices and circuits, e.g. phase shifters, power amplifiers, low noise amplifiers, mixers etc. However, when designing such arrays, the interplay between array performance characteristics, such as gain, side lobe level, back lobe level, mutual coupling etc. must …

An Application Of Dempster-Shafer Fusion Theory To Lithium-Ion Battery Prognostics And Health Management, John Weddington

Theses and Dissertations

Prognostics and Health Management (PHM) is the discipline involving diagnostics and prognostics of components or systems, with the primary objective of increasing the overall reliability and safety of these components or systems. PHM systems convert raw sensor data into features, and utilize state observers to estimate the current damage state online. Popular state observers are the traditional Kalman filter, along with its non-linear extensions, and the particle filter. Each technique has differing advantages. This thesis investigates the fusion of results from different techniques in order to achieve a more trustworthy probability of detection (PoD) during diagnosis and a more reliable …

Growth And Characterization Of Anisotropic Gase Semiconductor For Radiation Detection And Thz Applications, Haseeb Nazir

Theses and Dissertations

Anisotropic wide-bandgap gallium selenide (GaSe) crystals were grown using high purity (7N) Ga and zone refined (ZR) Se precursor materials. The crystal growth was performed using a modified vertical Bridgman method (VBM) with a slow crystallization from the melt and with a pre-determined temperature profile. The structure, surface morphology, and the composition of the grown crystals were characterized using x-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive analysis by x-rays (EDAX), respectively. Optical absorption and transmission properties were characterized and optical bandgap was determined. Electrical resistivity has been determined using current-voltage (I V) measurements using van der Pauw …

Data Analysis And Application Guidelines Of Particle Gel Treatments, Yue Qiu

Doctoral Dissertations

“Water production is a severe worldwide issue in mature oilfields, which results in shortening the economic life of oil and gas wells. Particle gel have been widely applied in mature oilfields to improve reservoir sweep efficiency and control water production. To date, more than 10,000 injection wells were successfully treated by particle gels. However, considerable uncertainty still exists regarding to where and how particle gel treatments can be best applied.

The main objective of this study is to provide application guidelines and prediction model for particle gel treatments through data analysis. In this study, four particle gel treatment datasets have …

Autonomous Driving Platform Performance Analysis, Charles R. Rickarby

Honors Theses and Capstones

Through data analysis of various plots and figures it will be possible to determine the best control parameters to get the best performance out of the autonomous driving platform. This data, presented in this thesis, will show quantitatively what the best control strategies are through comparison of different versions of the platform.

Synthesis Of Copper Oxide Nanoparticles In Droplet Flow Reactors, Christopher Reilly

Honors Theses and Capstones

Synthesis of metal oxide nanoparticles within droplet flow reactors is advantageous over batch synthesis due to the elimination of concentration and temperature gradients inside the reactor and prevention of reactor fouling. We present results on the synthesis of copper oxide nanoparticles using aqueous droplets of copper acetate and acetic acid inside a bulk stream of sodium hydroxide in 1-octanol. Varying the copper acetate, acetic acid, and sodium hydroxide concentration resulted in needle-like and plate-like nanoparticles of varying sizes. The rate of mass transfer from the bulk to the droplet phase was found to increase with flow rate and addition of …

Sensor Characterization And Signal Fusion For Instanteye, Wyman T. Smith

Honors Theses and Capstones

The practicality and effectiveness of using a TerraRanger Duo—a parallel sonar and infrared time-of-flight distance sensor—payload for obstacle detection is investigated for use with Physical Science Inc.’s InstantEye drone. A Python program was developed to interface with the serial data output before comparing the sensor’s empirical performance against its data sheet. The two signals from the distinct sensor modules, each with their characterized strengths and weaknesses, were then fused with a Kalman filter. This was further refined by imposing conditional weighting based on the known sensor characteristics. The filter output, with conditional corrections, was able to accurately track a single …

A New Reinforcement Learning Algorithm With Fixed Exploration For Semi-Markov Decision Processes, Angelo Michael Encapera

Masters Theses

"Artificial intelligence or machine learning techniques are currently being widely applied for solving problems within the field of data analytics. This work presents and demonstrates the use of a new machine learning algorithm for solving semi-Markov decision processes (SMDPs). SMDPs are encountered in the domain of Reinforcement Learning to solve control problems in discrete-event systems. The new algorithm developed here is called iSMART, an acronym for imaging Semi-Markov Average Reward Technique. The algorithm uses a constant exploration rate, unlike its precursor R-SMART, which required exploration decay. The major difference between R-SMART and iSMART is that the latter uses, in addition …

A Bounded Actor-Critic Algorithm For Reinforcement Learning, Ryan Jacob Lawhead

Masters Theses

"This thesis presents a new actor-critic algorithm from the domain of reinforcement learning to solve Markov and semi-Markov decision processes (or problems) in the field of airline revenue management (ARM). The ARM problem is one of control optimization in which a decision-maker must accept or reject a customer based on a requested fare. This thesis focuses on the so-called single-leg version of the ARM problem, which can be cast as a semi-Markov decision process (SMDP). Large-scale Markov decision processes (MDPs) and SMDPs suffer from the curses of dimensionality and modeling, making it difficult to create the transition probability matrices (TPMs) …

Wrinkling Of Functionally Graded Sandwich Structures Subject To Biaxial And In-Plane Shear Loads, Harold Costa

Masters Theses

"Benefits of a functionally graded core increasing wrinkling stability of sandwich panels have been demonstrated in a recent paper [1] where a several-fold increase in the wrinkling stress was observed, without a significant weight penalty, using a stiffer core adjacent to the facings. In the present paper wrinkling is analyzed in case where the facings are subject to biaxial compression and/or in-plane shear loading and the core is arbitrary graded through-the-thickness. Two issues addressed are the effect of biaxial or in-plane shear loads on wrinkling stability of panels with both graded and ungraded core and the verification that functional grading …

Dynamic Electromechanical Characterization Of Ferroelectrics At Cryogenic Temperatures, William Kent Hays

Masters Theses

"Electromechanical coupling in ferroelectric materials has given rise to a myriad of technological applications. Through the complex domain structure of ferroelectrics materials, which are typically stiff and have low damping, can exhibit significant structural damping. The applications for a material with a relatively large Young’s modulus and the ability to damp out vibrations would be useful for structures, more specifically, aerospace structures. The dynamic mechanical properties of ferroelectrics, particularly mechanical properties while an electric field is applied, are not well understood. This is due in part to the lack of experimental methods to measure such properties. Even with recent advancements …

Ti-Fe Intermetallics Analysis And Control In Joining Titanium Alloy And Stainless Steel By Laser Metal Deposition, Wei Li

Masters Theses

"Direct fusion joining titanium alloy and stainless steel can cause brittle Ti-Fe intermetallics which compromise the mechanical properties of diffusion bonds between titanium alloys and stainless steel. Therefore, filler metals are required as transition layers. In this research, stainless steel metallic powder was directly deposited on the titanium alloy substrate by laser beam, the Ti-Fe intermetallic phases formed in this process were investigated through analyzing fracture morphology, phase identification, and Vickers Hardness Number (VHN). After that, Laser Metal Deposition (LMD) was applied to explore a new fabricating process to join Ti6Al4V and SS316. A transition composition route was introducedTi6Al4V → …

Biodegradable Capacitive Pressure Sensor Toward Temporary Implants For Intervertebral Pressure Monitoring, Devdatt Chattopadhyay

Masters Theses

"The objective of this thesis is to demonstrate a new class of implantable biomedical device, based on biodegradable borate glass as the substrate material that can be potentially used to monitor the intervertebral pressure in the lumbar region of the human body. Two major types of implantable biomedical devices include the permanent prosthetic devices such as pacemakers and the temporary implants for short-term intervention and monitoring. Unless surgically removed after their intended operation, the temporary implants are left inside the body causing electromagnetic issues, latent complications and various biomechanical safety concerns. In order to address this issue, a new device …

Comparison Of ²⁵²Cf Time Correlated Induced Fission With Amli Induced Fission On Fresh Mtr Research Reactor Fuel, Jay Prakash Joshi

Masters Theses

"The effective application of international safeguards to research reactors requires verification of spent fuel as well as fresh fuel. To accomplish this goal various nondestructive and destructive assay techniques have been developed in the US and around the world. The Advanced Experimental Fuel Counter (AEFC) is a nondestructive assay (NDA) system developed at Los Alamos National Laboratory (LANL) combining both neutron and gamma measurement capabilities. Since spent fuel assemblies are stored in water, the system was designed to be watertight to facilitate underwater measurements by inspectors. The AEFC is comprised of six ³He detectors as well as a shielded …

An Experimental Study Of Non-Metallic Inclusions Precipitation And Its Effect On Impact Toughness Variations In Low Alloy Steel Subjected To Complex Deoxidation, Pavel Bizyukov

Dissertations and Theses @ UNI

A low level of non-metallic inclusions in steel is the key requirement in the concept of clean steel. Although the concept has received its name quite recently, it has been implemented at the large-scale steel mills for more than 40 years. Production of clean steel became possible due active development and adoption of the post-melting treatment of molten metal in the teeming ladle. Ladle metallurgy, an umbrella term for various methods of treatment, includes operations that cannot be performed during primary metallurgical processes such as melting in an electric arc, basic oxygen, or air induction furnace. Initially, the most common …

Survey And Data Analysis Of Weak Gel Treatments In Injection Wells, Zhuxing Chen

Masters Theses

"Excessive water production is a major concern in mature reservoirs. Weak gels have been applied in injection wells for in-depth profile modification. However, the data range and distribution of each parameter that affects performance of weak gels have not been studied thoroughly.

China has the largest amount of chemical-based conformance control treatments. This paper presents a summary of comprehensive data ranges and distributions for weak gel treatments based on the laboratory experiments and field applications in China from 2001 to 2010. The data set includes 76 cases compiled from China Academic Journals papers. In this study, reservoir properties, gel properties …

Towards A Better Understanding Of Indoor Exposure To Air Pollutants: Window Opening Occurrence In U.S. Residences, Gauri Dilip Date

Masters Theses

"Opening a window dramatically alters how we are exposed to air pollutants. Online questionnaire surveys were deployed to assess window-opening occurrence of the occupants of US homes. This information will be used to better quantify population exposure to pollutants of indoor and outdoor origin. Frequency distributions of demographics were generated which showed percentages of respondents who participated in the surveys from categories including gender, race, household income and occupancy. In April 2016, 49.3% of the people surveyed opened their windows for at least 1 hour in a day. This increased to 52.5% in September 2016 and reduced considerably to 24.4% …

Design And Analysis Of A Passive Heat Removal System For A Small Modular Reactor Using Star Ccm+, Raymond Michael Fanning

Masters Theses

"Next generation nuclear power plants, specifically small modular reactor designs, are the best alternative to fossil fuels for power generation due to their power density and low carbon emissions and constant awareness of safety concerns. A promising safety feature of new designs is the removal of heat by passive systems in accident scenarios. The passive systems require no moving parts and no intervention by personnel. These systems must be accurately simulated for better understanding of the heat transport phenomena: natural convection cooling. Due to the fact that most work developing these passive heat removal systems are proprietary information, a passive …

Combined Flue Gas Cleanup Process For Simultaneous Removal Of SoX, NoX, And Co₂ -- A Techno-Economic Analysis, Amit Narendrasing Hajari

Masters Theses

"Flue gas cleanup often requires the removal of SO_x, NO_x and CO₂ in separate units before atmospheric emission. The step-wise treatment process currently in place incurs significant cost and energy penalty. A single-step adsorption process based on pressure swing adsorption (PSA) by which these impurities are removed is envisioned as an efficient means of flue gas cleanup that can be applied relatively easily. In this study, the technological and economic feasibility of a single-step separation process in which SO_x, NO_x and CO₂ are simultaneously removed from flue gas streams are assessed. Capital …

High Speed Serial Link Design With Multi-Level Signaling And Characteristic Impedance Extraction From A Transmission Line With Meshed Ground Planes, Jiayi He

Masters Theses

"Channel bandwidth and manufacturing process have become two limitations in today's high speed designs. In order to overcome the channel bandwidth limitation, multilevel signaling is seen as one of the ways to achieve higher data rates. Using multilevel signaling as the coding scheme will impose new challenges in high speed serial link design. Due to manufacturing limitations, only transmission lines with meshed ground planes are allowed in some applications. Meshed power and ground planes have been widely used in today's flexible PCB designs to satisfy repeatability installation and reliability requirements.

In Section 1, high speed serial link design with PAM4 …

Plug-In Hybrid Electric Vehicle Load Profile Estimation With Opportunity Charging, Reza Kazem Sharif Sharifi

Masters Theses

"This thesis focuses on the load profile analysis of the plug-in hybrid electric vehicles (PHEV), examining two different scenarios. In the first scenario, the battery of a PHEV is charged at the final arrival time, and the arrival time analysis has a minute accuracy. In the second scenario, opportunity charging, which refers to the stop-time between two trips, is used for charging the battery of the vehicle. However, if the stop-time between two trips is less than 30 minutes, the duration is not counted as an opportunity charging and it is filtered. The results of the two scenarios are compared, …

Mold Flux Crystallization And Mold Thermal Behavior, Elizabeth Irene Peterson

Masters Theses

"Mold flux plays a small but critical role in the continuous casting of steel. The carbon-coated powder is added at the top of the water-cooled copper mold, over time it melts and infiltrates the gap between the copper mold and the solidifying steel strand. Mold powders serve five primary functions: (1) chemical insulation, (2) thermal insulation, (3)lubrication between the steel strand and mold, (4) absorption of inclusions, and (5)promotion of even heat flux. All five functions are critical to slab casting, but surface defect prevention is primarily controlled through even heat flux. Glassy fluxes have high heat transfer and result …

Evaluation Of Swelling And Re-Swelling Of Preformed Particle Gels (Ppg) When Exposed To Co₂, Sujay Suresh

Masters Theses

"Long term water/gas flooding induces high permeability channels in reservoirs. Reservoir heterogeneity becomes the most prominent challenge faced in mature oil fields. Gel treatment has been a proven solution to counter the problem of reservoir heterogeneity, to provide in-depth treatment and improve the sweep efficiency for reservoirs. Preformed particle gels (PPGs) were developed as an alternative to in-situ gels as they preferentially penetrate and shutoff high permeability zones, leaving the low permeability zones undamaged. These gels have been predominantly used in water flooding projects, but have not been employed in carbon dioxide (CO₂) flooding projects. CO₂ Resistant …

Evaluation Of Non-Chromate Passivations On Electroplated Γ-Phase Zinc Nickel, Steven Michael Volz

Masters Theses

"This research focused on the corrosion response and electrochemical behavior of electroplated low hydrogen embrittlement alkaline γ-phase zinc nickel with passivation layers. The motivation was the need to replace hexavalent chromium conversion coatings in military grade electrical systems with a more environment friendly alternative. The passivation layers were employed for the purpose of mitigating corrosion attack while maintaining low contact resistance. Trivalent chromium-based passivations and cerium-based passivations were compared against the currently used hexavalent chromium conversion coating. The coating systems were compared using electrochemical impedance spectroscopy, cyclic potentiodymanic scans, salt spray exposure testing, electrical resistance measurements, microstructure analysis, and compositional …

Extending Time Series Forecasting Methods Using Functional Principal Components Analysis, Isaac Michael Wagner-Muns

Masters Theses

"Traffic volume forecasts are used by many transportation analysis and management systems to better characterize and react to fluctuating traffic patterns. Most current forecasting methods do not take advantage of the underlying functional characteristics of the time series to make predictions. This paper presents a methodology that uses Functional Principal Components Analysis (FPCA) to create smooth and differentiable daily traffic forecasts. The methodology is validated with a data set of 1,813 days of 15 minute aggregated traffic volume time series. Both the FPCA based forecasts and the associated prediction intervals outperform traditional Seasonal Autoregressive Integrated Moving Average (SARIMA) based methods"--Abstract, …

Dc-Dc Converter Based Photovoltaic Simulator With A Double Current Mode Controller, Weichao Zhang

Masters Theses

"This thesis presents the performance of a DC-DC converter based with current mode controller photovoltaic (PV) simulator which emulates the output characteristics of a real PV module. A portable PV simulator prototype of 85 W is examined in terms of its steady state IV curve matching capacity and the convergence time corresponding to step change in current source load, voltage source load, and insolation levels. The current-voltage (IV) characteristics of the PV module are implemented as a look-up-table (LUT) which determines the reference output current from measured output voltage. A Thevenin Equivalent Method approach to PV arrays analysis is also …

Processing, Microstructure, And Properties Of Engineered Diboride Structures, Connor Charles Wittmaier

Masters Theses

"The mechanical properties and processing parameters of boride ceramics in foam and laminate architectures were evaluated. The ceramic reticulated foam was produced through a polymer substrate replication technique and the hardness and compressive strength were tested. The laminate structure was tested to evaluate the flexure strength and work of fracture as a function of temperature.

The foam architecture was produced using a TiB₂ slurry coating on a polyurethane reticulated foam preform. Foams sintered to 2150⁰C displayed an average grain size of 8.9 ± 7.3 µm, and a hardness of 17.3 ± 2.4 GPa. Crush testing foams were sintered at …

Hydrogeochemical Controls On Reactive And Nonreactive Solute Transport In Heterogenous Porous Media, Mahta Gholizadeh Ansari

Masters Theses

"This work examines how physical and chemical heterogeneity can affect reactive and non-reactive transport in porous media. The effect of heterogeneity of the porous media is investigated both on dissolution rate of magnesite and attenuation time of nonreactive contaminants in non-reactive media. Various spatial distribution were created using statistical parameters in PETREL.A total of 6793 transport modeling simulations were run using CrunchFlow. Lasso regression was used to select most significant features and those features are then used in linear regression and deep learning models.

The magnesite dissolution simulations were performed under different permeability ratios (magnesite /sand permeability) and inlet pH. …

Application Of Millimeter-Wave Differential Probe For Crack Detection On Riveted Structures, Kuang Ping Ying

Masters Theses

"This thesis proposes the use of a W-band wideband differential probe for crack detection on riveted structures, such as aircraft fuselage lap joints. Detection of crack at its early stage (surface-breaking) is particularly important to prevent the development of a fatigue crack. This probe utilizing millimeter-wave frequencies serves as a viable candidate on detecting surface-breaking cracks, as it can be employed in measurements in a non-contact fashion, while allowing for high spatial-resolution images and the abilities to penetrate through dielectric materials (paint), making it attractive for detecting small cracks. In previous works, a V-band differential probe has shown promise for …