Digital Commons Network^™

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 …

Care-Chair: Opportunistic Health Assessment With Smart Sensing On Chair Backrest, Rakesh Kumar

Masters Theses

"A vast majority of the population spend most of their time in a sedentary position, which potentially makes a chair a huge source of information about a person's daily activity. This information, which often gets ignored, can reveal important health data but the overhead and the time consumption needed to track the daily activity of a person is a major hurdle. Considering this, a simple and cost-efficient sensory system, named Care-Chair, with four square force sensitive resistors on the backrest of a chair has been designed to collect the activity details and breathing rate of the users. The Care-Chair system …

Assessing Downstream Stormwater Impacts For Urban Watershed Planning, Johanna Meyer Pavlowsky

Masters Theses

"The urbanization of watersheds has caused debilitating effects to downstream aquatic ecosystems in catchments and streams. The implementation of green infrastructure (GI), such as permeable pavements and bioretention facilities, has been shown to alleviate these effects by both reducing runoff and mitigating pollutants; however, the implements are often not designed with a specific goal of water improvement. This study targets understanding a small, impaired urban watershed, and the benefits green infrastructure may have to provide environmental, social, and economic improvement to the watershed.

Portions of Rolla including much of the S&T campus drain into the impaired urban waterbody Frisco Lake, …

Material Properties Affecting The Penetration Of Metal Targets By Copper Linear Shaped Charges, Kevin Lee Phelps

Masters Theses

"A linear shaped charge (LSC) is an explosive device used in demolition, aerospace, and in other applications that require the cutting of metal. Users of LSC's typically know the size of shaped charge needed to cut their target but commonly encounter previously untested materials. The motivation for this thesis is to provide an understanding as to what target material properties are good indicators of cutting performance so the selection of LSC can be more efficient. The author found that penetration theories for other types shaped charges were insufficient for the LSC, possibly because of the relatively slow projectile created by …

Application Of Embedded Frequency Selective Surfaces For Structural Health Monitoring, Dustin Franklin Pieper

Masters Theses

"This thesis proposes the use of Frequency Selective Surfaces (FSSs) as an embedded structural health monitoring (SHM) sensor. FSSs are periodic arrays of conductive elements that filter certain frequencies of incident electromagnetic radiation. The behavior of this filter is heavily dependent on the geometry of the FSS and local environment. Therefore, by monitoring how this filtering response changes when the geometric or environmental changes take place, information about those changes may be determined. In previous works, FSS-based sensing has shown promise for sensing normal strain (a stretching or compressing geometrical deformation). This concept is extended in this thesis by investigating …

Numerical Analysis Of Flexural Slip During Viscoelastic Buckle Folding, Davi Rodrigues Damasceno

Masters Theses

"Flexural slip is considered to be an important folding mechanism contributing in the development of different folds such as chevron, and kink-band buckle folds. Various filed studies have provided a general conceptual and qualitative understanding of flexural slip. However, quantitative evidence of the importance of the flexural slip mechanism during fold evolution is sparse, as the actual amount of surface parallel displacement, and timing, is difficult to measure accurately, due to the lack of suitable strain markers.

In this study 2D finite element analysis is used to overcome these disadvantages and to simulate flexural slip during viscoelastic buckle folding. Variations …

Evaluation Of Ultra-High Performance Concrete (Uhpc) In Joints Of Bridge Girders, Saipavan Rallabhandhi

Masters Theses

"Joints are often considered as the weak link in a structure and often deterioration of the structure initiates from the joints. Joints transfer the stresses from super-structure to sub-structure and in this process are subjected to large transfer stresses. Not much attention is given to the design of joints as they are positioned in low moment regions and typically a 4 to 6 ksi (28 to 41 MPa) concrete is used to fill the joints. One of the solution to this problem is Ultra-high performance concrete (UHPC). In the recent past significant research has been done to use UHPC in …

Data Analysis Of Surfactant-Induced Wettability Alteration In Carbonate Reservoirs, Hao Sun

Masters Theses

"Most carbonate formations prove to be oil-wet due to oil aging effect. Therefore it is essential to employ wettability alteration methods for a more effective enhanced oil recovery process. It is confirmed by researchers that surfactant treatment has positive effects on wettability alteration of carbonate rock, from strong oil-wet to intermediate wet or to even weak water-wet. A number of experiments have the same conclusion and yet, a systematic screening guide development with the support of sufficient data analysis is lacking.

This study involves screening guide development for surfactant-induced wettability alteration method. 199 experiments collected from published literatures are analyzed …

Artificial Neural Network Approach To Predict Blast-Induced Ground Vibration, Airblast And Rock Fragmentation, Raymond Ninnang Tiile

Masters Theses

"Blasting has been widely used as an economical and cheap way of rock breakage in mining and civil engineering applications. An optimal blast yields the best fragmentation in a safe, economic and environmentally friendly manner. The degree of fragmentation is vital as it determines to a large extent the utilization of equipment, productivity and mill throughput. Explosive energy, besides rock fragmentation, creates health and safety issues such as ground vibration, air blast, fly rock, and back breaks among others. As a result, the explosive energy impacts structures and buildings located in the vicinity of the blasting operation, and causes human …

Avon Alkaline Igneous Province, Missouri: Characterization Of Subcontinental Mantle Source And Evolution Via Chemical Analysis Of Olivine, Zachary William Freeman

Masters Theses

"This article presents the crystallization age of, and composition of olivine phenocrysts within an alnoite of, the Avon Alkaline Igneous Province (AAIP) of Ste. Genevieve County, Missouri. The AAIP is an ultramafic igneous province consisting of approx. 80 known intrusives of diverse lithology and texture. ⁴⁰Ar/³⁹ Ar geochronology indicates an emplacement age of 386 +/- 1 Ma, which establishes the AAIP as the only known Devonian-age ultramafic igneous body in the Midwestern U.S. Study of the AAIP provides a unique opportunity to characterize the Devonian-age subcontinental mantle and the processes that generated the suite of ultramafic rocks present …

The Evaluation Of Sequential Optimization And Reliability Analysis, Guannan Liu

Masters Theses

"Sequential Optimization and Reliability Assessment (SORA) has been used for more than one decade for reliability-based design (RBD), but comprehensive theoretical studies on its performance have not been conducted. Further investigations on its performance are still needed. The objective of this thesis is to evaluate the performance of SORA for various testing problems. The performance of SORA evaluated in this thesis includes (1) accuracy, (2) efficiency, and (3) convergence behavior or robustness with numerical testing problems. SORA is evaluated with comparison with other major RBD methodologies. The testing problems are in different scales (numbers of design variables, random variables, and …

Pim Source Identification Using Vibration Modulation Method, Sen Yang

Masters Theses

“In Section 1, passive intermodulation (PIM) is introduced and the mechanism of it is briefly explained. Then, the up-to-date PIM testing and source identification method in the industrial and academia worlds will be summarized.

The vibration modulation method for PIM source identification is proposed in Section 2. Different vibration sources were tested and compared, and the test results showed that the vibration modulation method is able to identify PIM source with good accuracy.

Section 3 outlines a special PIM source identification system built based on the vibration modulation system. The two subsystems, PIM receiver and PIM vibrator, are illustrated in …

Composite Model Representation For Computer Aided Design Of Functionally Gradient Materials, Fangquan Wang

Masters Theses

"Functionally Gradient Materials (FGMs) feature smooth transition from one material to another within a single object. FGMs modeling is considered to be one of the new challenges in Computer Aided Design (CAD) area. To overcome this challenge, this thesis presents a composite approach to model FGMs. The input in STL format can be meshed and voxelized in FGMs modeling system. The material composition in each voxel can be generated from multiple different types of control features. And LTI filters including Gaussian Filter and Average Filter are applied to blur default material features in order to generate FGMs inside models. The …