Digital Commons Network^™

Effect Of Timing And Source Of Online Product Recommendations: An Eye-Tracking Study, Qing Zeng

Masters Theses

"Online retail business has become an emerging market for almost all business owners. Online recommender systems provide better services to the consumers as well as assist consumers with their decision making processes. In this study, a controlled lab experiment was conducted to assess the effect of recommendation timing (early, mid, and late) and recommendation source (expert reviews vs. consumer reviews) on e-commerce users' interest and attention. Eye-tracking data was extracted from the experiment and analyzed. The results suggest that users show more interest in recommendation based on consumer reviews than recommendation based on expert reviews. Earlier recommendations do not receive …

A Linear Matrix Inequality-Based Approach For The Computation Of Actuator Bandwidth Limits In Adaptive Control, Daniel Robert Wagner

Masters Theses

"Linear matrix inequalities and convex optimization techniques have become popular tools to solve nontrivial problems in the field of adaptive control. Specifically, the stability of adaptive control laws in the presence of actuator dynamics remains as an important open control problem. In this thesis, we present a linear matrix inequalities-based hedging approach and evaluate it for model reference adaptive control of an uncertain dynamical system in the presence of actuator dynamics. The ideal reference dynamics are modified such that the hedging approach allows the correct adaptation without being hindered by the presence of actuator dynamics. The hedging approach is first …

Mitigation Of Wellbore Instability In Deviated Wells By Using Geomechanical Models And Mpd Technique, Husam Raad Abbood

Masters Theses

"During drilling operations for the E oilfield in the Mishrif formation in southern Iraq, stuck pipe presents a significant wellbore stability problem for deviated wells. In this study, two solutions are utilized to address this problem. The first approach is a 1-D Geomechanical model of the Mishrif formation compiled based on the state of stress and rock strength parameters. It is utilized to assess the contribution of borehole collapse leading to the stuck pipe problems. The results of this study show that wells characterized by stuck pipe are drilled along azimuths which promote wellbore collapse. Three different failure criteria, the …

Conceptual Parameters Necessary For Modeling Wettability Alteration In An Enhanced Smart Brine-Chalk System, Ahmed Abdulkareem Hussein Albahrani

Masters Theses

"Achieving higher recovery of oil from proven carbonate reserves around the world is not an easy task. One promising new method, especially for carbonate reservoirs, is the use of "Smart Water" technology, which is an injection water with carefully determined, optimal ionic composition and salinity. Recent experiments have shown good recovery results, but the mechanism of wettability alteration by this fluid are still not well understood. The goal of this study is to review the high and optimal salinity and ionic composition literature plus perform dimensional analysis of key variables in order to shed light on the physical and chemical …

Design And Analysis Of An Axisymmetric Aerospike Supersonic Micro-Nozzle For A Refrigerant-Based Cold-Gas Propulsion System For Small Satellites, Abdalla Ali Bani

Masters Theses

"The cold-gas propulsion system being developed by M-SAT requires improvements to its original nozzle design. This study documents the research, design, and analysis of a supersonic plug nozzle concept that could be integrated to the refrigerant-based cold-gas propulsion system to possibly improve its performance. As documented in this thesis, CFD analysis showed that the outlined nozzle design method resulted in a feasible nozzle concept that has the ability to out-perform a conventional nozzle of the same area ratio. The flow-fields and thrust of the aerospike nozzle, for the full and truncated nozzles, were investigated. The purpose of this study is …

Voltage Control In A Distribution System Using Active Power Loads, Mounika Chava

Masters Theses

"High penetration of renewable energy resources such as rooftop solar photovoltaic (PV) systems is exacerbating violations of the voltage limits in power distribution networks. Existing solutions to these over-/under-voltage issues include tap-changing transformers and shunt capacitors. However, tap changers only allow voltage changes in discrete steps and shunt capacitors cannot handle over-voltage situations. To overcome these problems, this thesis proposes voltage control in a distribution system by adjusting active power loads. The proposed solution can be used for both under- and over-voltage cases at any levels of voltage adjustment. First, the active power that needs to be adjusted at selected …

A Statistical Analysis Of A 4.5 Mw Solar Energy Center, Archit Patnaik

Masters Theses

"This project helps a regional utility evaluate the performance of their 4.5 MW photovoltaic plant. The performance evaluation consists of characterizing the peak and average power and energy output of the plant over varying time periods. A characterization of the output power drops, or dips, is done by performing a statistical analysis of the photovoltaic plant output data. Dips are characterized by dip frequency, depth of dip, energy loss by dip, and dip duration. The results of this study will help the utility to select appropriate voltage regulating equipment on the basis of dip characteristics, and thus, optimize the performance …

Addressing The Influence Of Carbon Monoxide On The Behavior Of An Hcci Engine, Allen Charles Ernst

Masters Theses

"Homogeneous Charge Compression Ignition (HCCI) may be the next leap of improvement to internal combustion engines due to its decreased emissions and improved engine efficiencies. However, such a jump possesses challenges owing to its strict reliance on the inherent physics that dictate start of combustion and limit the reach of stable operation. This work investigates the role and fundamental influence of carbon monoxide on the cycle-to-cycle combustion dynamics present in the region of incomplete combustion that frames the limited HCCI operating region. An improved understanding will open doors to enhanced control methodologies and an expanded stable operating envelope. A constant …

An Investigation Of Plugging And Increasing Oil Recovery In Sandstone Porous Media By Micrometer-Size Particle Gel, Haifeng Ding

Masters Theses

"Micrometer-size particle gel (microgel) has been developed and successfully applied to improve conformance in mature reservoirs. However, quite few researches have been published to address on their effect on oil recovery and rock permeability modification.

This work conducted a series of core flooding experiments to investigate the injectivity, plugging efficiency and improving oil recovery potentials of a couple of microgels synthesized in our lab.

First, this work studied the impact of permeability and crosslinker concentration on PAM type microgel treatment. Results shows that microgel treatment would have a less plugging efficiency in lower permeability rocks, which could be caused by …

Design Methodology For Behavioral Surface Roughness Modeling And High-Speed Test Board Design, Xinyao Guo

Masters Theses

"A behavioral model is introduced, which can predict low-loss and low surface roughness transmission line time- and frequency- domain performances. High data rates push for better performance of PCB transmission lines. However, the roughness of copper foil has a considerable impact on the signal integrity performance of transmission lines at high data rates and long propagation distance. Existing models for low-loss transmission line surface roughness are inadequate. A new behavioral model to represent the surface roughness has been developed. The model is applied in the design process by adding a dispersive term to the bulk dielectric permittivity to represent the …

Impact Of Repeated Cyclic Production Scheme On Eur In Low-Permeability Reservoirs, Samarth Gupte

Masters Theses

"Productivity in low-permeability reservoirs declines quickly compared to conventional reservoirs. These tight reservoirs have very high initial oil production rates but as soon as the oil near the fractured area is recovered, the production declines rapidly making economic oil and gas production a challenge for the industry. This study investigates the impact of repeated shut-in/production cycles on the ultimate recovery of oil in such environments.

A reservoir model with multiple fractured horizontal well having 30 transverse fractures is created using CMG. Reservoir permeability is varied over the range of 0.000001 md to 10 md and shut-in/production cycles of 2-weeks, 1-month, …

Design, Scale-Up, Six Sigma In Processing Different Feedstocks In A Fixed Bed Downdraft Biomass Gasifier, Sai Chandra Teja Boravelli

Masters Theses

"This thesis mainly focuses on design and process development of a downdraft biomass gasification processes. The objective is to develop a gasifier and process of gasification for a continuous steady state process. A lab scale downdraft gasifier was designed to develop the process and obtain optimum operating procedure.

Sustainable and dependable sources such as biomass are potential sources of renewable energy and have a reasonable motivation to be used in developing a small scale energy production plant for countries such as Canada where wood stocks are more reliable sources than fossil fuels. This thesis addresses the process of thermal conversion …

Characterization Of Electric Solid Propellant Pulsed Microthrusters, Matthew Scott Glascock

Masters Theses

"Electric solid propellants are an attractive option for space propulsion because they are ignited by applied electric power only. In this work, the behavior of pulsed microthruster devices utilizing such a material is investigated. These devices are similar in function and operation to the pulsed plasma thruster, which typically uses Teflon as propellant. A Faraday probe, Langmuir triple probe, residual gas analyzer, pendulum thrust stand and high speed camera are utilized as diagnostic devices. These thrusters are made in batches, of which a few devices were tested experimentally in vacuum environments. Results indicate a plume electron temperature of about 1.7 …

Protection Of A 138/34.5 Kv Transformer Using Sel 387-6 Relay, Aamani Lakkaraju

Masters Theses

"Schweitzer Engineering laboratories (SEL) donated the SEL 387, SEL 311L, and SEL 351S relays and the SEL AMS to Missouri University of Science and Technology. This thesis documents the demonstration approach to set the SEL 387 relay to protect a grounded wye-grounded wye transformer and then test these settings by injecting fault currents into the relay using the SEL AMS. This thesis explains the approach to set the differential element of the SEL 387 relay to protect a transformer against internal faults and the overcurrent element of the SEL 387 relay to protect transformer against external faults. A radial power …

Study And Development Of Robust Preformed Particle Gels For Conformance Control, Yifu Long

Masters Theses

"To improve the oil recovery of mature reservoirs, technologies referring to conformance control have been widely developed and implemented. Among various technologies, preformed particle gel (PPG) treatment has attracted increasing attentions. PPGs, as a kind of deformable plyometric superabsorbent, could be pumped through injection wells as plugging agents to block the fracture or high-permeability zone in a reservoir.

In decade usage of PPGs, an intensively employed material is poly(acrylamide) (PAM) based hydrogel. However, conventional PAM gel did reveal deficient in formidable conditions, such as formations with high temperature and high salinity. Therefore, a novel PPG based on starch-grafting-poly(acrylamide)/nano-composite (SAC) hydrogel …

Computational Fluid Dynamics (Cfd) Simulations Of Molten Steel Flow Patterns And Particle-Wall Adhesion In Continuous Casting Of Steels, Mahdi Mohammadi-Ghaleni

Masters Theses

"In this research, the measurements of clog deposit thickness on the interior surfaces of a continuous casting nozzle were compared with Computational Fluid Dynamics (CFD) predictions of melt flow patterns and particle-wall interactions to identify the mechanisms of nozzle clogging. A hybrid turbulent approach, Detached Eddy Simulation (DES), was configured to simulate both turbulent structures and particle-wall interactions inside the nozzle accurately. For experimental measurements of nozzle clogging, a nozzle received from industry was encased in epoxy and carefully sectioned to allow measurement of the deposit thickness on the internal surfaces of the nozzle. CFD simulations of melt flow patterns …

Provenance And Depositional Environments Of Fluvial-Lacustrine Sandstones Of Lower Permian Lucaogou Low-Order Cycle, Bogda Mountains, Nw China, Xiaowei Peng

Masters Theses

"Compositional and textural maturity of sandstones may reflect provenance lithology and sediment transport distance, which are useful for paleogeographic reconstruction. 37 sandstones in six outcrop stratigraphic sections in Tarlong-Taodonggou and Zhaobishan areas in the greater Turpan-Junggar rift basin were studied to investigate the fluvial-lacustrine sandstone provenance in lower Permian Lucaogou (LCG) low-order cycle, Bogda Mountains, NW China. 400 points were counted in each thin section. All the samples are classified into lithic arenites, subarenites, wackes, and mudrocks. Three Petrofacies are defined. Petrofacies A is characterized by a high lithic content which is dominantly basaltic lithics with minor sedimentary lithics and …

Surface Modification Of Tin Oxide Nanoparticles By Atomic Layer Deposition For Enhanced Electrochemical Performance, Sai Abhishek Palaparty

Masters Theses

"Atomic Layer Deposition is a robust technique used to deposit high quality, conformal, and size-tunable ultrathin films on a substrate. This technique can be used to coat protective films on battery anode and cathode materials for enhanced performance. In the case of cathodes, the ultrathin film provides a protective barrier preventing cationic dissolution. In the case of anodes, the film acts as a supporting matrix reducing strain caused by volume expansions. In these study, we use this technique to coat an optimally thick conductive iron oxide film on tin oxide particles to improve its electrochemical performance at high current densities …

Hydrodynamic Of A Co-Current Gas Liquid Upflow In A Moving Packed Bed Reactor With Porous Catalysts, Ali Jabbar Toukan

Masters Theses

"In this study, the hydrodynamic, i.e. flow regime identification, line average liquid holdup, and the internal liquid holdup of a co-current moving packed bed reactor were studied. For the sake of hydrodynamics study, moving bed reactor is investigated as two-phase upflow packed bed reactor. Scaled down configuration was used to simulate of the moving bed reactors utilized in the industrial process. First, line average liquid holdup is measured with different geometrical configurations covering empty, dry, wet, and packed column under flowrates operation conditions. A new methodology has been developed to determine the line average liquid holdup for a porous catalyst. …

Origin Of Lacustrine Carbonate-Dominated Clinoforms In The Lower-Permian Lucaogou Low-Order Cycle, Southern Bogda Mountains, Nw China, Yiran Lu

Masters Theses

"Lacustrine carbonate clinoforms deposit can reflect ancient lake condition like paleoclimate and lake type. Complex lithofacies of a carbonate-dominated clinoform package in lower Permian Lucaogou low order cycle, Bogda Mountains, NW China, provide clues on clinoform-forming processes in a half-graben lake. The clinoform package is ~5.2 m thick, prograding from S to N for ~200 m with a maximum 15o dip angle, and spans ~4 km laterally. A clinoform consists of a lower siliciclastic-rich and an upper carbonate-rich beds, forming a clinoform cycle. Results of petrographic study of 30 thin sections suggest that the clinoform package is composed of mixed …

Correlation Anaylsis Of Magnesite Dissolution Rate And Magnesite Spatial Distribution, Yao Wang

Masters Theses

"This thesis presents a correlation analysis of the spatial distribution and permeability of magnesite dissolution and focuses on its overall rate and average porosity. Magnesite dissolution is affected by several aspects.

A reservoir's large spatial distribution can make capturing the magnesite dissolution difficult, so in this study, a variogram was built in Petrel using a percentage variation of magnesite and sand. The variogram also handles different major and minor directions in anisotropy. After building the magnesite model, simulation of magnesite dissolution was achieved in Cruch Flow to get the magnesite dissolution rate and average porosity.

For correlation analysis, a regression …

Design Of An Adaptive Force And Stiffness Controlled Compliant Device For Robotic Polishing, Mohammad Masud Parvez

Masters Theses

"Polishing is a repetitive task done in an unhealthy environment. Often more than half of the manufacturing time is required to polish a die. The manual polishing process is a tedious work actively rely on a skilled human worker. Industrial Robot has replaced the human in performing these tasks. For robotic polishing to control the polishing force, an active compliant device is used. Due to the compressibility of air, a pneumatic system is preferred as the actuator of the device. The force of the actuator is controlled by regulating air pressure in both chambers of the cylinder. However, to improve …

Reduction Of Emi Due To Common Mode Current Using Common Mode Filter Or Lossy Material, Qian Liu

Masters Theses

"This thesis consists of four papers. In the first paper, two new common mode filter structures were designed, fabricated, and measured. A "sandwich-type" EBG structure that resonates at the desired filter frequency is designed to suppress common mode filter on differential signals. The new filters are placed on top of the PCB as a surface-mount component, instead of being implemented within the PCB stackup. The total radiated power (TRP) of the implemented filter is investigated and discussed. RF absorbing material and traditional shielding are considered to reduce the TRP.

In the second paper and third paper, new PCB-embedded common mode …

Construction And Validation Of Tl-Ipm Generator, Jamaluddin Mohammad

Masters Theses

"Hydrokinetic energy is one of the potential sources of energy that can be extracted and converted to electrical energy using linear generator. This work discusses about construction and validation of tubular linear internal permanent magnet (TL-IPM) generator, a kind of linear generator. The generator could produce electricity by converting linear motion generated from vortex induced vibrations induced due from a flowing fluid, such as a river. A simulation model of the generator is created using Ansoft's Maxwell software, which uses finite element analysis to perform electromagnetic analysis of the generator. Then a practical generator was built and tested. The results …

Oxidative Dehydrogenation Of Light Alkanes With Carbon Dioxide, Marktus A. Atanga

Masters Theses

”Most experts studying the global ecosystem and climate suggest that rising anthropogenic CO₂ emissions have contributed to significant global climate change in the last half-century. The development of effective strategies that convert CO₂ into energy, fuels, and chemicals are greatly preferable to oceanic or geologic sequestration options because they offer the potential to create new commercially-viable products from renewable carbon feedstock. On the other hand, the selective oxidative dehydrogenation of light alkanes (C₂-C₄) to corresponding olefins, methane reforming, and methane coupling are the major challenges for producing valuable and versatile feedstocks. The oxidative dehydrogenation …

Gravity And Magnetic Investigations Of The North-Eastern Kansas Section Of The Midcontinent Rift System, Ozgun Kamil Sahin

Masters Theses

"The Midcontinent Rift System (MRS) is a major Precambrian magmatic province on the North American continent. It formed when the North American craton began to split apart during the Mesoproterozoic era (1,100 Ma). As a result of the extension and possibly the effects of a rising mantle plume, a thick layer of basalt and numerous reverse and normal faults were formed. The basalt layer is buried below sedimentary formations and makes it difficult for seismic techniques to image. On the other hand, gravity and magnetic methods can be utilized for focused depths, and the basalt layer of the system can …

Phase Field Modeling Of Electrodeposition Process In Lithium Metal Batteries, Nihal Acharya

Masters Theses

"One of the main weaknesses in long term performance of conventional lithium batteries is the growth of lithium microstructures on the electrode surface due to an electrochemical process, which can eventually lead to failure of these batteries. Suppressing this microstructure growth is a key in developing new generations of lithium metal batteries (LMBs). In this study, a two-dimensional (2D) phase field model is constructed to understand and determine the parameters controlling formation and evolution of microstructures in LMBs. A Ginzburg-Landau free energy functional, which is a function of concentration of Li⁺ and applied voltage, and a system consisting of …

Mechanics Of Impulse Force Reduction For Mitigating Dump Truck Vibrations Under Hislo Conditions, Danish Ali

Masters Theses

"The deployment of large capacity shovels and dump trucks, for achieving economic bulk production capacities, has resulted in high impact shovel loading operations (HISLO). These large shovels generate high impact forces when loading dump trucks with over 100-ton passes under gravity. The impact forces also generate high frequency shock waves, which cause severe truck vibrations, and thus, expose dump truck operators to high levels of whole body vibrations (WBV). The dynamic impact force generates these vibrations, and thus, there is a need to develop efficient technologies to eliminate or reduce its impact. Existing literature and industry practice show that this …

Behavior Of Ultra-High Performance Concrete Bridge Deck Panels Compared To Conventional Stay-In-Place Deck Panels, Valter Gora Venancio

Masters Theses

"The remarkable features of ultra-high performance concrete (UHPC) have been reported. Its application in bridge construction has been an active research area in recent years, attributed to its higher compressive strength, higher ductility and reduced permeability when compared with conventional concrete and even high-strength concrete. Those characteristics are known to increase bridge durability and, consequently, decrease life-cycle maintenance costs.

With that in mind, this study investigated the performance of UHPC stay-in-place (SIP) bridge deck panels subjected to high loads in both flexure and shear. The test matrix consisted of twelve (12) half-scale panels that were 4 feet long and 2 …

Using Adaptive Thresholding And Skewness Correction To Detect Gray Areas In Melanoma In Situ Images, Jason R. Hagerty

Masters Theses

"The incidence of melanoma in situ (MIS) is growing significantly. Detection at the MIS stage provides the highest cure rate for melanoma, but reliable detection of MIS with dermoscopy alone is not yet possible. Adjunct dermoscopic instrumentation using digital image analysis may allow more accurate detection of MIS. Gray areas are a critical component of MIS diagnosis, but automatic detection of these areas remains difficult because similar gray areas are also found in benign lesions. This paper proposes a novel adaptive thresholding technique for automatically detecting gray areas specific to MIS. The proposed model uses only MIS dermoscopic images to …