Engineering Commons^™

Hardened Mechanical Properties And Durability Performance Of Specialized Concretes, Kyle Richard Holman

Masters Theses

"Concrete is one of the most produced and utilized materials in the world. Due to the labor intensive and time consuming nature of concrete construction, new and innovative concrete mixes are being explored. Self-consolidating concrete (SCC) is one such method of improving the overall cost and time efficiency of concrete production. SCC is a highly flowable form of concrete. This characteristic drastically reduces the amount of labor and time needed to place the concrete. The highly flowable nature also allows for much easier placement in applications of highly congested reinforcement.

Another rising concern in today's construction industry is environmental responsibility. …

Wavelet Based Contrast Limited Histogram Equalization For Contrast Enhancement Of Digital Mammography, Ashish Vighnahar Avachat

Masters Theses

"Mammography has been the most efficient tool for screening of microcalcification and cancer tissues; however, the raw images produced by mammography systems are usually of poor contrast. In order to use these raw images for early diagnosis; their contrast, sharpness and noise need to be enhanced. Among these important enhancement parameters contrast enhancement is critical. A novel algorithm is introduced which blends wavelet transforms with Contrast Limited Adaptive Histogram Equalization (CLAHE) for contrast enhancement. In this algorithm, the input image is decomposed to its low frequency and high frequency components in wavelet domain. Decomposed coefficients from different bands are then …

Development Of A Shared Earth Model To Investigate Potential For Carbon Dioxide Sequestration In The Springfield Area, Mo, Imowo Celestine Akpan

Masters Theses

"Carbon dioxide (C0₂) sequestration has been extensively implemented and explored predominantly in depleted oil reservoirs and deep saline aquifers where the C0₂ is stored under supercritical conditions. A lesser explored option with great potential is based on injection into shallow reservoirs where the C0₂ may not always be in its denser supercritical state. The research evaluates the potential for injecting C0₂ into saline aquifers at depths of ~550-650 meters and formation temperatures of -22⁰C.

To evaluate injectivity and cap rock integrity, reservoir and geomechanical simulations need to be conducted separately and subsequently coupled. A Shared Earth Model is developed utilizing …

A Three-Dimensional Transient Simulation Of An Electrochemical Magnetohydrodynamics Cell With Micro And Millielectrode: A Unified Reconciliation Of Theory And Experiment, Cajon Gonzales

Masters Theses

"Even though electrochemically induced magnetohydrodynamic (MHD) convection is a straightforward inexpensive method for moving fluids in confined spaces as for example during electrodeposition, stripping voltammetry, or in microfluidics, efficient quantitative models only recently have begun to appear. This is traced to complex mathematics that have prevented development of analytical expressions, e.g., for mass-transfer limited currents in analogy to the well-known Levich equation for the rotating electrode. Thus, related literature expressions remain mainly phenomenological concerning particular cell geometries or applications. Here, using such reports as points of departure, we validate a computationally rigorous description of the magnetoelectrochemical problem and define the …

Impact Of Interruptions In White Collar Working Environment, Zafar Akhil Khan

Masters Theses

"An interruption is a randomly occurring, discrete event that breaks continuity of cognitive focuses on a primary task and typically requires immediate attention and insists on action. "White collar interruptions" are those that affect knowledge workers in professional, managerial, or administrative positions. Interruptions are often a common occurrence in the white collar workplace.

The aim of this thesis is to investigate the effect of timing of an interruption on the overall performance of white collar workers. This study also analyzes the interruption sources (i.e. externally and internally generated) along with effect of different types of interruptions on both demanding and …

Prototyping And Testing Of Solar Hybrid Pv-T Panels, Joel Aaron Lamson

Masters Theses

"The combination of photovoltaic and solar thermal (PV-t) systems has been proven to provide greater efficiency than their stand-alone counterparts. Previous studies on hybrid assemblies have found favorable results supporting the combination of both systems. The research presented here builds on the work competed here at Missouri University of Science and Technology (Missouri S&T) yielding favorable results of increased efficiencies as compared to stand-alone systems. The main difference between this experiment and previous research at Missouri S&T is that the hybrid PV-t is unglazed. The effect of an unglazed panel is shown to reduce the thermal output of the PV-t …

Cerium-Based Conversion Coatings On Cast Aluminum 380 And 413 Alloys, Ci Lin

Masters Theses

"This investigation focused on the deposition and characterization of cerium-based conversion coatings (CeCCs) on cast aluminum alloys. Previous research has shown that CeCCs are viable alternatives to chromate conversion on high strength alloys such as 2024-T3 and 7075-T6. For the casting alloys such as 380 and 413, the presence of Si affects the composition and stability of the native oxide, which means that pretreatment plays an important role for the coating deposition. This thesis consists of two papers that describe the results of the study.

The first paper reports the effect of the final rinsing temperature before coating deposition on …

Spiking Neural Networks Encoding And Decoding Algorithms For Time Series Estimation And System Identification, Sinchan Roychowdhury

Masters Theses

"Artificial Neural networks (ANNs) have increasingly been applied to different system identification, pattern recognition and function approximation problems. The predominantly used neural network architectures are the feedforward and feedback networks. Multilayer perceptrons and radial basis function networks are among the most commonly used feed-forward architecture neural networks and the Elman and Jordan networks are the most widely used recurrent neural networks. These networks are also called as second generation ANNs.

This thesis focuses on the third generation ANNs which are biologically inspired and operate on the same principles as the living neurons. These are also known as biologically inspired artificial …

In Planta Solid Phase Sampling Devices Used In Delineating Groundwater Contaminant Plumes, Mikhil Kishore Shetty

Masters Theses

"The widespread and indiscriminate use of chlorinated volatile organic compounds as cleaning agents at dry - cleaning facilities, as metal degreasers and solvents in extraction and removal operations has been well documented in the past resulting in releases, while contaminating soil and groundwater. Current techniques to assess chlorinated solvents such as tetrachloroethylene (PCE) and trichloroethylene (TCE) in the subsurface have been time and cost intensive and more importantly invasive to the surrounding environment. New methods use trees as sources of information to access contaminant plume size and plume delineation. The major goal of these research studies has been to save …

Analyses Of Surface Wave Seismic Data And Supplemental Borehole And Electrical Resistivity Tomography Control, Mengxing Li

Masters Theses

"Multichannel analyses of surface wave (MASW) data and electrical resistivity tomography (ERT) control were acquired at two test sites in central Missouri. Limestone bedrock existed at both test sites at variable depths. The ground surface at both test sites was relatively flat.

The primary objective was to map the variable depth to the top of the rock based on shear-wave velocity contrasts. ERT data and borehole control were acquired at each site in order to constrain the interpretation of the MASW data.

The MASW method proved to be more effective than the ERT method in terms of mapping soil layers …

Modeling Supply Chain Network Resiliency In The Aftermath Of An Extreme Event, Varun Ramachandran

Masters Theses

"Failure of infrastructure elements due to an extreme event adversely affects the supply chain networks in any urban environment. This study models the resiliency of a supply chain network by integrating geospatial data with critical supply chain elements and graph theory. This model can then be combined with an extreme event simulation to calculate resiliency. Resiliency refers to the time required for services and select economic indicators to approach pre-event levels (in this study, a return to 80% of the pre-event capacity). This research proposes an interdisciplinary approach to develop a comprehensive framework for resiliency modeling. This approach includes the …

Studies Of Inductive Plasmas And Their Application To Theta-Pinch Devices Via Numerical Modeling, Warner C. Meeks

Masters Theses

"First, a globally-averaged RF plasma model is used to investigate exit conditions immediately following a RF pre-ionization stage. Analysis shows that reducing pulse duration from 10⁻⁶ to 10⁻⁷ seconds increases peak ion energy fraction by 17% (from 16 to 33%) and doubles final conductivity. Pulse waveforms are square in nature, and ion energy fraction is defined in this work as the percentage of total input energy entrained in ions. Increasing total energy deposition from 5 to 160 mJ increases ion energy fraction from 33% to 58% at a 200 ns pulse duration. This increase is not linear however, showing instead …

Intelligent Energy Management And Demand-Response Control For A Photovoltaic-Battery System, Yang Liu

Masters Theses

"The work shown in this thesis is to develop an intelligent energy management and demand-response controller (IEMDC) for a photovoltaic-battery (PVB) system with a programmable load. Specifically, the research work related to this issue focuses on the modeling and real-time simulation of a microgrid with an emphasis on photovoltaic, battery and programmable load and the development of an energy management controller for optimally dispatching the power from the PVB system to the loads. The IEMDC is used for daytime grid-independent operation. The energy management controller is based on fuzzy logic controller (FLC) whose membership functions are optimized using mean-variance optimization …

Design And Verification Of Clockless Advanced Encryption Standard (Aes) Crypto-Hardware For Improved Side-Channel Attack Resistance, Siva Pavan Kumar Kotipalli

Masters Theses

"The Advanced Encryption Standard (AES) is the most widely used symmetric key algorithm standard in different security protocols. The AES was very reliable in providing security for data until a few years ago, when researchers proved the Side Channel Attacks (SCA) like power analysis were successful in compromising this security.

This thesis focuses on designing effective countermeasures against the SCA's, by exploring the usage of an Asynchronous logic based design approach, called Null Convention Logic (NCL). This work discusses the design of NCL based subset of AES cryptosystem. The performance benefits of this novel cryptosystem are presented by making qualitative …

Implementation And Evaluation Of Spatial Audio Recording And Rendering Techniques, Jayasecha Raghavendra Nimmala

Masters Theses

"The thesis is divided into two main sections. First half describes the implementation of different adaptive beamforming techniques. Adaptive beamforming techniques are widely used in many real world applications like teleconferencing, speech recognition, devices for the hearing impaired, radar, sonar, etc. The beamformer is an array of sensors which can be electronically steered to any particular direction to enhance the signal in the direction of interest while at the same time suppressing interference or jammers coming from other directions.

In our experiment, we implement both the regularized minimum variance distortionless receiver (MVDR) and the generalized sidelobe canceller (GSC). The beamforming …

Energy Efficiency In Wastewater Treatment: Standards For Missouri Facilities, Samantha Lauren Markus

Masters Theses

"Traditionally, energy has been used to treat wastewater. As energy costs rise, so does the financial burden on communities with municipal wastewater treatment plants (WWTP). Determining energy efficiency of small to mid-sized plants is difficult because these plants are the least likely to have the resources to conduct an energy audit and the most likely to be overlooked in national models due to their small contribution to the national energy burden. Data was gathered via personal contact the WWTPs in Missouri and from this data metrics fro comparison were developed. The data was also compared to the predicted energy use …

Microlens Array Light Trapping In Cdte/Cds Solar Cells, Patrick Michael Margavio

Masters Theses

"In light of the continued rise in fossil fuel costs, alternative energy sources, such as solar technology, are increasingly important. Concentrating photovoltaic systems are promising for future efficient and cost effective competition with fossil fuels. A microlens array is employed to a CdTe/CdS semiconducting solar cell to increase efficiency via light trapping. Since the microlens array will cause a local increase in incident light intensity, it should cause a corresponding increase in efficiency. The solar cell is deposited layer by layer. The CdS layer is chemically deposited. The CdTe layer is deposited using a novel additive manufacture technique: laser melting …

Information Theoretic Analysis And Design Of Passive Wireless Backscatter Sensor Networks, Aditya V. Padaki

Masters Theses

"Passive, backscatter-based communication technology is increasingly employed in wireless sensing applications. It offers several advantages including small form factor, battery-less operation, increased system lifetime, small configurations, etc. The main focus of this work is to study the theoretical limits of the network performance in such passive sensor networks. In addition to the traditional direct communication between an active and several passive devices (like RFID), the information theoretic analysis considers two new communication frameworks: multi-hop and multipath passive networks. These new frameworks are demonstrated through theoretical and simulation results to improve the network performance and fairness over the traditional direct communication. …

Commercial Construction Supply Chain Management Issues Involving Traveling Contractors, Fred Akers

Masters Theses

Supply chain management (SCM) is an important aspect of running any business. To stay competitive in today's marketplace a supply chain management system must be in place to achieve success in this volatile global environment (Fewings, 2005).

This research differentiates the issues between executing a construction project close to home compared to away from home. Being away from home, there typically is no supplier relationship established. Furthermore, the research intends to document certain issues of the commercial construction industry that develop during the execution of a project. This will be based on the comparison of having or not having an …

Parametric Study Of Gear Rattle And The Effect Of Flexible Enclosures On Gearbox Vibratory Responses, Joshuah Thomas Racine

Masters Theses

Gearbox noise emitted from vehicles has become of particular importance to manufacturers due to the significant reduction of engine and masking noises in most modem designs. The reduction of gearbox rattle was the subject of this research using Romax Designer. Both drive and neutral loading conditions were considered for a parametric study of the influence of altering input torque fluctuation, backlash between gears, component rigidities and driveline inertia. Next, an external enclosure was added, where its effect was studied by altering the wall thickness, material properties and fixed boundary positions. Finally, results obtained from Romax Designer for a physical gearbox …

On-Board Monitoring Of Engine Oil, Ryan James Clark

Masters Theses

Engine oil condition was quantified in a diesel engine through direct, real-time measurements of lubricant properties using an on-board oil-condition sensor. The sensor measures the lubricant temperature, density, dynamic viscosity and dielectric constant. Comparative bench-top experiments using ASTM methods or equivalent techniques validated the accuracy and precision of the lubricant property measurements from the oil-condition sensor for a specific temperature range. Bench-top experiments were also used to establish correlations between fuel contamination levels and changes in lubricant properties.

Through engine experiments, the change in the lubricant properties with respect to operating time was quantified. A correlation was found between the …

Comparison Of Martin’S Empirical Correlation With Measurements On A Compact Plate Heat Exchanger, Abdulmohsen A. Alothman

Masters Theses

The need for more effective heat exchangers is becoming more necessary these days. At the same time, the size of the heat exchanger also plays a big role. Therefore, in many applications the compact plate heat exchanger is used where high effectiveness and small size are required. As a result, it is a necessary to study and understand the performance of compact plate heat exchangers. More specifically, the performance of heat transfer, represented by the Colburn factor j, and friction factor f, must be deeply studied and understood.

A mathematical model has been built to express f and j factors …

Evaluation Of Silver/Graphite Ink Blends For Use In Printed Electronics, Sagar Satish Joshi

Masters Theses

Many organizations around the globe are actively involved in the research and development of printed displays, circuits, printed batteries, RFID tags and other printed electronics applications. The requirements for using printing techniques in the manufacturing of circuits are much more demanding than for conventional printing.There are many challenges that have to be overcome for successful printing and functioning of the printed circuits. These challenges are not only for the printing process and the substrates, but also for the functional inks used for printed electronics manufacturing.

This work focuses on gravure printing of conductive inks, more specifically silver, graphite and silver-graphite …

A Method For Calibration Of Speed-Flow Curves In Hcm 2010 And Determination Of Highway Capacity, Seyed Hadii Khazraee Khoshroozi

Masters Theses

"This study proposes a method for calibration of speed-flow curves in a format suggested by the Highway Capacity Manual (HCM) 2010 and applies it to two sites in Missouri: a work zone on I-44 around Pacific, and a basic freeway segment on I-270 in St. Louis. The three-regime model proposed is based on the two-regime (free-flow and transition) uncongested relationship suggested by the HCM 2010, complemented with a third regime representing congested conditions. Further, this study proposes a systematic approach based on regression analysis to determine capacity i.e., the break-point (intersection) between the transition and congested regimes. The proposed method …

Laboratory Studies Of Compatibility Of Tamper Detection Materials With Improvised Explosive Device Crater Repairs, Levi Anthony Smith

Masters Theses

"Past methods for road repairs of craters caused by improvised explosive devices (IEDs) on main supply routes (MSRs) and alternative supply routes (ASRs) in Iraq and Afghanistan have been problematic. Traditional temporary and permanent solutions have proven deficient by being easily penetrable or by exposing troops for long periods of time. The use of a pre-blended rapid hardening cementitious material for lED crater repair has solved issues such as quick placement of the repair and high strength of the repair within an hour of placement. However, there are still issues with IEDs being hidden in repairs tampered by or replicated …

Density Determination Of Tristructural-Isotropic Nuclear Fuel Using Multiple Projection X-Ray Radiography, Frank Angelo Strantz

Masters Theses

"Effective methods of enhancing the safety and efficiency of the nuclear power industry embolden its perception and economic viability. Fuel reliability is an essential component of the prosperity of next generation high temperature reactors; as such, an equally dependable quality control method is mandatory. Tristructural-isotropic (TRISO) fuel, the fuel developed for use in these reactors, utilizes density measurement of coating layers as a standard for quality control. Common methods of measuring density, such as sink-float and ceramography are destructive, and as such generate radioactive waste, take a relatively long time to prepare samples, rely on a low sampling rate to …

Hardened Concrete Properties And Durability Assessment Of High Volume Fly Ash Concrete, Kyle Marie Marlay

Masters Theses

"Concrete is produced more than any other material in the world. Sustainable construction is extremely important in today's industry and fly ash is the leading material for sustainable concrete design. The addition of fly ash improves many fresh and hardened concrete properties. However, the slow hydration process associated with fly ash makes the use of the material in large amounts undesirable in conventional construction. This study evaluated the hardened concrete and durability performance of several high-volume fly ash (HVFA) concrete mixes. The various HVFA concrete mixes evaluated within this study consisted of 70 percent replacement of portland cement by weight …

Hall-Effect Thruster Surface Properties Investigation, David George Zidar

Masters Theses

"Surface properties of Hall-effect thruster channel walls play an important role in the performance and lifetime of the device. Physical models of near-wall effects are beginning to be incorporated into thruster simulations, and these models must account for evolution of channel surface properties due to thruster operation. Results from this study show differences in boron nitride channel surface properties from beginning-of-life and after 100's of hours of operation. Two worn thruster channels of different boron nitride grades are compared with their corresponding pristine and shadow-shielded samples. Pristine HP grade boron nitride surface roughness is 9000±700 Å, while the worn sample …

Field Programmable Gate Array Based Multiple Input Multiple Output Transmitter, Richa Shekhar

Masters Theses

"MIMO is an advanced antenna technology compared to Single Input Single output (SISO), Multiple Input Single Output (MISO), and Single Input Multiple Output (SIMO) and is used to obtain high data rate in the system. Multiple-Input Multiple-Output (MIMO) systems have at least two transmitting antennas, each generating unique signals. However some applications may require three, four, or more transmitting devices to achieve the desired system performance. This thesis describes a comparison between different approaches like the microcontroller, ASICs and the FPGA available in the market for baseband signal generation. It also describes the design of a scalable MIMO transmitter, based …

Bi-Harmonic Atomic Force Microscopy, Santosh R. Kodandarama

Masters Theses

"In tapping mode atomic force microscopy, surface features are measured indirectly via the amplitude of the tapping cantilever. A change in surface profile is detectable only if it results in an amplitude change that is significant enough to be measured by the optics. Previous works have focused on improving sensitivity through the system's Q-factor, either by changing physical cantilever properties or using feedback control, but those approaches undesirably slow down the dynamic response. In this work we take a novel approach to sensitivity amplification by reshaping the tapping trajectory. By shaping the trajectory so that the probe spends a greater …