Digital Commons Network^™

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 …

Uface: Your Universal Password No One Can See, Nicholas Steven Hilbert

Masters Theses

"With the advantage of not having to memorize long passwords, facial authentication has become a topic of interest among researchers. However, since many users store images containing their face on social networking sites, a new challenge emerges in preventing attackers from impersonating these users by using these online photos. Another problem with most current facial authentication protocols is that they require an unencrypted image of each registered user's face to compare against. Moreover, they might require the user's device to execute computationally expensive multiparty protocols which presents a problem for mobile devices with limited processing power. Finally, these authentication protocols …

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 …

In Situ Ph Determination Based On The Nmr Analysis Of ¹H-Nmr Signal Intensities And ¹⁹F-Nmr Chemical Shifts, Ming Huang

Masters Theses

"The pH of an NMR sample can be measured directly by NMR experiments of signal intensities, chemical shifts, or relaxation time constants that depend on the pH. The ¹H NMR peak intensities of the pH indicator phenolphthalein change as it changes from the OH-depleted form to the OH-rich form in the range of pH = 11.1 to 12.7. Because this range is rather small, another NMR technique was utilized based on ¹⁹F chemical shifts. The shift of F^- in an aqueous solution of NaF changes in the alkaline range between pH = 11.0 and 14.0 and even …

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 …

Family-Based Association Studies Of Autism In Boys Via Facial-Feature Clusters, Luke Andrew Settles

Masters Theses

"Autism spectrum disorder (ASD) refers to a set of developmental disorders with varied attributes. Due to its substantial heterogeneity in terms of behavioral and clinical phenotypes, it is challenging to discern the genetic biomarkers behind ASD, even though the disease is known to be genetic in nature. This serves as a motivation to detect relationships between single nucleotide polymorphisms (SNPs) and a causal autism disease susceptibility locus (DSL) within more homogeneous subgroups. Recently, clinically meaningful subclassifications of ASD have been discovered utilizing facial features of prepubescent boys. Therefore, through the employment of data from 44 prepubertal Caucasian boys with ASD …

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 …

Provenance And Depositional Environments Of Fluvial-Lacustrine Deposits In A Non-Marine Rift Basin, Lower-Triassic Jiucaiyuan And Shaofanggou Low-Order Cycles Bogda Shan, Nw China, Jaimeson Grigaitis Fredericks

Masters Theses

"The uppermost Carboniferous to Lower Triassic eolian-fluvial-lacustrine deposits of Turpan-Junggar Basin, NW China, record the non-marine sediment-filling processes in a continental rift basin in mid-latitude NE Pangea. This study focuses on the fluvial-lacustrine strata of the Lower Triassic Jiucaiyuan (JCY) and Shaofanggou (SFG) low-order cycles (LCs) in multiple half grabens at the southern and northern foothills of Bogda Shan. Outcrop, paleocurrent, and petrographic analyses indicate a southern provenance. Intermediate to felsic volcanic lithics and metamorphic lithics are interpreted as being derived from Tian Shan to the south while the sedimentary lithics originate from the local rift shoulders. The basaltic lithics …

The Pantograph Equation In Quantum Calculus, Thomas Griebel

Masters Theses

"In this thesis, the pantograph equation in quantum calculus is investigated. The pantograph equation is a famous delay differential equation that has been known since 1971. Till the present day, the continuous and the discrete cases of the pantograph equation are well studied. This thesis deals with different pantograph equations in quantum calculus. An explicit solution representation and the exponential behavior of solutions of a pantograph equation are proved. Furthermore, several pantograph equations regarding asymptotic stability are considered. In fact, conditions for the asymptotic stability of the zero solution are derived and subsequently illustrated by examples. Moreover, an explicit solution …

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, …

A Review Of Random Matrix Theory With An Application To Biological Data, Jesse Aaron Marks

Masters Theses

"Random matrix theory (RMT) is an area of study that has applications in a wide variety of scientific disciplines. The foundation of RMT is based on the analysis of the eigenvalue behavior of matrices. The eigenvalues of a random matrix (a matrix with stochastic entries) will behave differently than the eigenvalues from a matrix with non-random properties. Studying this bifurcation of the eigenvalue behavior provides the means to which system-specific signals can be distinguished from randomness. In particular, RMT provides an algorithmic approach to objectively remove noise from matrices with embedded signals.

Major advances in data acquisition capabilities have changed …

Personalizing Education With Algorithmic Course Selection, Tyler Morrow

Masters Theses

"The work presented in this thesis utilizes context-aware recommendation to facilitate personalized education and assist students in selecting courses (or in non-traditional curricula, topics or modules) that meet curricular requirements, leverage their skills and background, and are relevant to their interests. The original research contribution of this thesis is an algorithm that can generate a schedule of courses with consideration of a student's profile, minimization of cost, and complete adherence to institution requirements. The research problem at hand - a constrained optimization problem with potentially conflicting objectives - is solved by first identifying a minimal sets of courses a student …

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, …

Sentiment Analytics: Lexicons Construction And Analysis, Bo Yuan

Masters Theses

"With the increasing amount of text data, sentiment analysis (SA) is becoming more and more important. An automated approach is needed to parse the online reviews and comments, and analyze their sentiments. Since lexicon is the most important component in SA, enhancing the quality of lexicons will improve the efficiency and accuracy of sentiment analysis. In this research, the effect of coupling a general lexicon with a specialized lexicon (for a specific domain) and its impact on sentiment analysis was presented. Two special domains and one general domain were studied. The two special domains are the petroleum domain and the …

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 …

Study Of Surface Complexation And Mineral Dissolution During Water-Rock Interaction In High Salinity Waterflooding At Elevated Temperatures, Sameer Salasakar

Masters Theses

"High salinity waterflooding for carbonate reservoirs is efficient and cheap method used for improved oil recovery. Various mechanisms have been proposed including adsorption/desorption on rock surface, mineral dissolution and precipitation, multicomponent ion exchange, interfacial tension reduction, fine migration and double layer expansion. These all process alter the wettability which leads to improved oil recovery.

Objective of this study was to understand processes that occur during water-rock interaction when high salinity water is flooded into the reservoir. In this work, effect of temperature on water-rock interaction is studied along with effect of pH and specific surface areas of calcite at normal …

Facebook And Value Congruence, Andrew James Eyberg

Masters Theses

"The current discussion on the use of social networking sites (SNS) in personnel selection is mixed at best. The present research utilized participant's Facebook profiles to determine if raters can correctly - and accurately evaluate work value dimensions as a measure of person-organization fit. Similar research was successful in capturing personality dimensions via SNS (Buffardi & Campbell, 2009). Additionally, the value dimensions of the current measure used -- the Organizational Culture Profile (OCP) (O'Reilly et al., 1991) has been correlated with aspects of personality. Rater participants (N=105). Every five raters were randomly assigned five profiles to rate, for a total …