Engineering Commons^™

Gas-Liquid Mass Transfer In A High Pressure Bubble Column Reactor With Different Sparger Designs, Lu Han, Muthanna H. Al-Dahhan

Chemical and Biochemical Engineering Faculty Research & Creative Works

The Gas-Liquid Mass Transfer in a 0.162 M High-Pressure Stainless-Steel Bubble Column Was Investigated using Three Different Gas Sparger Designs. an Oxygen-Enriched-Air Dynamic Method and an Optical Oxygen Probe Technique Were Implemented to Measure K1 a Values in the Bubble Column Reactor. using the Interfacial Area (A) Values Measured by a Four-Point Optical Probe Technique at Similar Conditions (Xue, 2004), the K1 Values Were Estimated. Axial Dispersion Model (ADM) and Continuous Stirred Tank Reactor (CSTR) Model Were Used to Calculate K1 a as a Fitted Parameter with the Measured Data. the ADM Gave Better Fits to the Experimental Data Than …

Irradiation And Metal-Containing Conjugated-Polymer Nanocomposites, Frank D. Blum, Zhe-Fei Li, Sunil K. Pillalamarri, Massimo F. Bertino

Chemistry Faculty Research & Creative Works

In recent years, there has been considerable interest in inorganic/organic hybrid materials that combine the desirable properties of both classes. These composite materials may find significant application in a variety of applications such as sensors, memory and energy conversion, to name just a few. In our laboratories, we have recently made a series of studies on the production of polymer nanofibers and their composites with nanometals. Much of this work has focused on the production of polyaniline (PANI) nanofibers that have been made from one-pot syntheses in aqueous solutions where the polymerization was influenced by -radiation1 or UV-radiation.2 in the …

A Computational Theory For The Generation Of Solutions During Early Conceptual Design, Cari R. Bryant

Doctoral Dissertations

"Advancement in technology is usually made by building on previous experiences and learning from past successes and failures. However, knowledge transfer in the broad field of product design is often difficult to accomplish. Research has shown that successful component configurations, observed from existing products, can be dissected and stored for reuse; but few computational tools exist to assist designers during the conceptual phase of design. Many well-known manual methods (e.g. brainstorming, intrinsic and extrinsic searches, and morphological analysis) rely heavily on individual bias and experience and are often time intensive, laborious tasks that may not catch solutions that are functionally …

Refrigerant-Based Propulsion System For Small Spacecraft, Carl Reiner Seubert

Masters Theses

"The MR SAT spacecraft under development at UMR requires a propulsion system that can be utilized to perform orbital maneuvers and three-axis attitude control to complete its mission objective of conducting spacecraft formation flight. This thesis documents the research, analysis design and development of the cold gas propulsion system that was integrated on the MR SAT spacecraft"--Abstract, page iii.

Security Architecture Methodology For Large Net-Centric Systems, Njideka Adaku Umeh

Masters Theses

"This thesis describes an over-arching security architecture methodology for large network enabled systems that can be scaled down for smaller network centric operations such as present at the University of Missouri-Rolla. By leveraging the five elements of security policy & standards, security risk management, security auditing, security federation and security management, of the proposed security architecture and addressing the specific needs of UMR, the methodology was used to determine places of improvement for UMR"--Abstract, page iii.

Use Of Analytical Hierarchy Process In University Strategy Planning, Mihir Gokhale

Masters Theses

"The selection of an appropriate strategy is critical for a university's success, and each university needs to capitalize on its own specialties and competencies for a competitive advantage. Strategy creation and planning in universities is generally a collective effort which relies on consensus. It is a complex process involving the setting of objectives and goals to achieve the strategic vision, and an analysis tool for evaluating and comparing different options and prioritizing objectives and goals is required. A high deductive capacity is necessary for aggregating the different trade-offs while prioritizing, which is challenging for a human mind. This thesis demonstrates …

Bridge Damage Detection Using An Intelligent Engineering System, Dionysios N. Danilatos

Masters Theses

"This thesis concerns the design of an algorithm that is capable to detect structural damage in civil infrastructure bridges. The algorithm, which will be dubbed Damage Diagnostics System throughout the thesis, is the software component of a broader Bridge Health Monitoring System. This broader system integrates software and hardware,such as sensors and data acquisition components...The rationale for the Structural Damage Diagnosis is based on the principle of the structural vibration testing. The Health Monitoring System captures the vibration signals, as the bridge responds to excitation from various sources. The purpose of the Diagnostic System is to extract information from the …

Equivalent Circuit For Transient Conduction And Convection Systems, Bassam Sabry Mohammad Abdelnabi

Masters Theses

"Transient response of a natural convection system is investigated by numerical simulation using FLUENT code. An Integrator Circuit analogy was recently proposed for natural convection system. The proposed analogy was further confirmed by these recent simulations. New simulation results also suggest that a natural convection system acts as a "Low Pass" filter for transients. Transient transmission/attenuation factor was found to be a function of both fluid properties and the flow characteristics. Transmission/attenuation factor was also found to be a strong function of fluctuation frequency"--Abstract, page iv.

Design And Implementation Of A Hardened Distributed Network Endpoint Security System For Improving The Security Of Internet Protocol-Based Networks, William Dee Atkins

Masters Theses

"This thesis proposes a distributed approach to securing computer networks by delegating the role of a conventional firewall to a collection of nodes and controllers placed throughout the networks they are intended toprotect from attack. This distributed firewall system is a specific application of a generalized distriubted system framework that is also proposed in this thesis. The design and implementation of both the generalized framework and the application of the framework in creating a distributed firewall system for use on Ethernet-based networks that rely on the Internet Protocol are discussed. Conclusions based upon the preliminary implementation of the proposed systems …

Integrated Product And Its Extended Enterprise Network Design Using Lean Principles, Abhijit K. Choudhury

Masters Theses

"Recently, many system integration companies have begun to intensely focus on suppliers' involvement in the product realization process to enhance their competitiveness. The product architecture has a huge impact on the efficiency of the integrator's supplier network. One of the ways to enhance efficiency is to implement the lean principles while creating a collaborative design/manufacturing/supply chain environment. In this study, two distinct stages of the product realization process, namely, design stage and production stage are considered for determining the design and production supplier networks"--Abstract, page iv.

Empirical Investigation Of Enhanced Air Fins, Stephen John Dale Rucker

Masters Theses

"Enhanced convective heat transfer surfaces have been a subject of interest for quite some time. Many different methods have been used to increase the amount of heat transfered from a surface. However, nearly all surface enhancement methods come with a price, frictional losses. This thesis studies the use of enhanced convective heat transfer surfaces on air fins in the laminar, transitional, and turbulent flow regimes with emphasis on the transitional regime. A major goal of this thesis is to further the understanding of the influence of an enhanced wall geometry on the transition from laminar to turbulent flow. Causing the …

Current Measurement In Power Electronic And Motor Drive Applications - A Comprehensive Study, Asha Patel

Masters Theses

"Current measurement has many applications in power electronics and motor drives. Current measurement is used for control, protection, monitoring, and power management purposes. Parameters such as low cost, accuracy, high current measurement, isolation needs, broad frequency bandwidth, linearity and stability with temperature variations, high immunity to dv/dt, low realization effort, fast response time, and compatibility with integration process are required to ensure high performance of current sensors. Various current sensing techniques based on different physical effects such as Faraday's induction law, Ohm's law, Lorentz force law, magneto-resistance effect, and magnetic saturation are studied in this thesis. Review and examination of …

Design For Test Techniques For Asynchronous Ncl Designs And Fpgas, Sindhu Kakarla

Masters Theses

"Testing of an electronic chip is an important step in the design process, as it can detect faults and ensure reliability. Design for Test (DFT) methods are used to modify existing designs to enable their testing by Automatic Test Pattern Generators. This thesis focuses on developing testing techniques for design automation of NULL Conventional Logic (NCL) circuits and for detection of capacitive crosstalk effects in Field Programmable Gate Arrays (FPGAs).

A novel technique is developed for testing asynchronous NCL designs aimed at good fault coverage with acceptable gate overhead. The technique focuses on testing stuck-at-faults in the internal feedback paths …

Impact Of Ammonia On The Leaching Characteristics Of Mercury From Coal Fly Ash, Harmanjit Mallhi

Masters Theses

"Approximately half of the electricity produced in the United States is generated by coal-fired power plants. Coal combustion products (CCPs) such as fly ash, bottom ash, flue gas desulphurization (FGD) material, boiler slag are either disposed in landfills or impoundments, or beneficially used...It has been long known that fly ash contains many trace elements (As, Se, Hg Cr, Cd, Ni, Pb, Cu,Co, etc.) that can be of environmental concern. Mercury is of special interest since it is a known carcinogen and has the ability to bio-accumulate. The primary objectives of thesis research were to understand the leaching behavior of mercury …

Preparation Of Bioactive Glasses With Controllable Degradation Behavior And Their Bioactive Characterization, Aihua Yao, Deping Wang, Qiang Fu, M. N. Rahaman, Wen-Hai Huang

Materials Science and Engineering Faculty Research & Creative Works

Bioactive glasses and ceramics have been widely investigated for bone repair because of their excel-lent bioactive characteristics. However, these biomaterials undergo incomplete conversion into a bone-like material, which severely limits their biomedical application. In this paper, borosilicate bioac-tive glasses were prepared by traditional melting process. The results showed that borosilicate glasses possessed high biocompatibility and bioactivity. In addition, when immersed in a 0.02 mol/L K2HPO4 solution, particles of a borate glass were fully converted to HA. The desirable conversion rate to HA may be achieved through the adjustment of the B2O3/SiO2 ratio. The results of XRD and FTIR analysis indicated …

Low-Thrust Control Of A Lunar Orbiter, Nathan Harl

Masters Theses

"This thesis presents a method for maintaining a long-term lunar Sun-synchronous orbit using continuous low-thrust hardware. The control method is developed using optimal control theory, which involves controlling a system through the minimization of a desired cost function"--Abstract, page iii.

Operation Of A Brushless Dc Drive For Application In Hybrid Electric Vehicles, James Scott Jenkins

Masters Theses

"One of the goals of a hybrid electric vehicle design is to improve the overall performance of the vehicle by incorporating several different power sources in such a way as to maximize the energy usage. By combining the desirable characteristics of each of the components in the system, the vehicle becomes more efficient to operate. Energy storage systems such as batteries and ultra-capacitors can be used to supply or store energy from the system when needed. The primary power source in this model will be an internal combustion engine coupled with a permanent magnet synchronous generator. The purpose of this …

Distribution System Operation And Planning In The Presence Of Distributed Generation Technology, Gavin Wesley Jones

Masters Theses

"Distributed generation (DG) is becoming an increasingly attractive power generation paradigm in the field of power engineering as economic and environmental factors drive new technologies to be more efficient and less polluting than their earlier counterparts. Although the concept of DG is not new, little research has been done on the topic and even fewer field tests have been performed. This lack of research, along with other factors, has somewhat slowed the acceptance of DG into markets, other than industrial or commercial co-generation for heat and power. This thesis attempts to examine and compare three types of DG: diesel generators, …

Diversity Techniques For Signal-Strength Based Indoor Location Determination, Anil Ramachandran

Masters Theses

"Diversity techniques have been found in the literature to be suitable for compensating channel uncertainties such as multipath fading. In this thesis, we exploit spatial and frequency diversity techniques for improving accuracy in locating stationary and mobile objects in the indoor environment"--Abstract, page iv.

Properties Of Alkaline-Resistant Calcium-Iron-Phosphate Glasses, Jiawanjun Shi

Masters Theses

"The physical properties and alkaline corrosion resistant properties of calcium-iron-phosphate glasses were studied. The addition of Fe₂O₃ decreases the thermal expansion coefficient and increases the glass fiber's Young's modulus in comparison with the addition of CaO. Bulk glass dissolution behavior in alkaline Lawrence solution was studied by weight loss experiments, Raman spectroscopy, and analytical scanning electron microscopy. The corrosion of glass powder in NaOH solution was studied by X-ray diffraction, infrared spectroscopy and high pressure liquid chromatography. The results show that the dissolution rate decreases when the phosphate chain length decreases. Calcium oxide can improve the glass durability in high …

Robust Mechanism Synthesis With Random And Interval Variables, Pavan Kumar Venigella

Masters Theses

"Robust mechanism synthesis ensures that the performance of a mechanism is not sensitive to uncertainties in the mechanism and its environment. The uncertainties include the dimension variations, installation errors, random input motion, and various external forces. Robust mechanism synthesis is used to minimize the impact of these uncertainties on the mechanism performance. Robust mechanism synthesis has been performed by either a probabilistic approach or a worst case approach. The former approach describes uncertain parameters as random variables while the latter approach treats uncertain parameters as interval variables. In this work, methods are developed for robustness assessment and robust mechanism synthesis …

Identification Of Radial Streaming And Pseudopods In Dermoscopy Images, Sayali Prabhakar Deshpande

Masters Theses

"This thesis demonstrates an algorithm to identify the features of radial streaming and pseudopods found in dermoscopy images of malignant melanoma. The algorithm includes preprocessing images using the Principal Component Transform and an application of mathematical techniques to extract the desired features from the lesion image on the basis of color, size, shape, and orientation with respect to the lesion boundary. These identified features are further used to classify the lesion as malignant or benign. The proposed algorithm has produced a diagnostic accuracy of 90.50% for the training set of 31 malignant and 109 benign images and a diagnostic accuracy …

Susceptibility Scanning System As Failure Analysis Tool For System Level Esd Problems, Giorgi Muchaidze

Masters Theses

"System level Electrostatic Discharges (ESDs) can lead to soft-errors (e.g., bit-errors, wrong resets). The goal of this project is to offer guidance in finding the root cause of soft-errors frequently observed using immunity scanning system. Immunity scanning is an increasingly adopted method for root cause analysis of system level immunity sensitivities. It allows localizing affected nets and ICs. At first a description of the ESD discharge process is given, which provides the necessary background for correctly analyzing ESD failures. Local scanning and in-circuit measurement techniques are expounded in this study. Further, it is shown how PCB scanning results can reveal …

Analysis Of Soil Erosion Based On Soil Properties, Preetha Veeraraghavan

Masters Theses

"The objectives of this research were to identify the major soil parameter(s) that affect the erosion rate of soil and to estimate the erosion rate based on those soil parameters. Both prepared samples and natural samples were used in this research. The soil properties analyzed were the water content, unit weight, Atterberg limits, and soil cohesion. The erosion rate was determined using a rectangular flume and a linear relation between the erosion rate and shear stress was established from the flume experiment. The slope of the linear relation was a good indicator of the soil's erosion rate. The erosion rate …

Bio Inspired Techniques For Simultaneous Design Of Multiple Optimal Power System Stabilizers, Tridib Kumar Das

Masters Theses

"Bio-inspired techniques are fields of study that are inspired from topics of connectionism, social behavior and emergence. Researchers have ventured into the intricacies involved with the techniques and devised algorithms based on their study. Such techniques are the focus of this thesis. The two bio-inspired techniques used for simultaneous design of power system stabilizers (PSSs) in this study are - Particle Swam Optimization (PSO) and Bacteria Foraging Algorithm (BFA). The work in this thesis is presented in three papers as follows: Paper 1 -This paper introduces an improved PSO called Small Population based PSO (SPPSO) with less number of particles …

Nondestructive Evaluation Of Rc Structures Strengthened With Frp Laminates Containing Near-Surface Defects In The Form Of Delaminations, Mahmut Ekenel, John J. Myers

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Fiber reinforced polymer (FRP) composites are being utilized in a wide range of application areas in structural rehabilitations because these materials are less affected by corrosive environmental conditions and known to provide longer life with less maintenance. However, there are still some concerns about FRP strengthened reinforced concrete (RC) structures, such as the presence of near-surface defects. Currently limited data exists regarding this issue. the presence of near-surface defects in the form of delaminations between the fiber reinforced polymer (FRP) laminate and concrete substrate can significantly affect the structural integrity and stiffness of the structural section. These defects should be …

Noise-Robust Automatic Speech Recognition Using A Discriminative Echo State Network, Mark D. Skowronski, John G. Harris

Electrical and Computer Engineering Faculty Research & Creative Works

The echo state network (ESN) is a recurrent neural network proposed by Herbert Jaeger with a simplified training routine. Previously, we have demonstrated the noise-robust performance of the predictive ESN classifier in automatic speech recognition experiments in which the network was trained to predict the next frame of speech features. Classification performance was limited because the predictive models lacked discriminability, so we changed the model output to a one-of-many output encodings scheme and trained the model discriminatively. Performance was compared to a hidden Markov model (HMM) in small-vocabulary ASR experiments with additive noise. Accuracy of 50% was achieved by a …

Reinforcement Learning Neural-Network-Based Controller For Nonlinear Discrete-Time Systems With Input Constraints, Pingan He, Jagannathan Sarangapani

Electrical and Computer Engineering Faculty Research & Creative Works

A novel adaptive-critic-based neural network (NN) controller in discrete time is designed to deliver a desired tracking performance for a class of nonlinear systems in the presence of actuator constraints. The constraints of the actuator are treated in the controller design as the saturation nonlinearity. The adaptive critic NN controller architecture based on state feedback includes two NNs: the critic NN is used to approximate the "strategic" utility function, whereas the action NN is employed to minimize both the strategic utility function and the unknown nonlinear dynamic estimation errors. The critic and action NN weight updates are derived by minimizing …

A Normalized Fractionally Lower-Order Moment Algorithm For Space-Time Adaptive Processing, Y. Rosa Zheng, Genshe Chen, Erik Blasch

Electrical and Computer Engineering Faculty Research & Creative Works

A new space-time adaptive processing algorithm is proposed for clutter suppression in phased array radar systems. In contrast to the commonly used normalized least mean square (NLMS) algorithm which uses the second order moments of the data for adaptation, the proposed method uses the lower order moments of the data to adapt the weight coefficients. The normalization is also performed based on the data sample dispersion rather than the variance. Processing results using simulated and measured data show that the proposed algorithm converges faster than the NLMS algorithms in Gaussian and non-Gaussian clutter environments. It also provides better clutter suppression …

Online Reinforcement Learning Neural Network Controller Design For Nanomanipulation, Qinmin Yang, Jagannathan Sarangapani

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper, a novel reinforcement learning neural network (NN)-based controller, referred to adaptive critic controller, is proposed for affine nonlinear discrete-time systems with applications to nanomanipulation. In the online NN reinforcement learning method, one NN is designated as the critic NN, which approximates the long-term cost function by assuming that the states of the nonlinear systems is available for measurement. An action NN is employed to derive an optimal control signal to track a desired system trajectory while minimizing the cost function. Online updating weight tuning schemes for these two NNs are also derived. By using the Lyapunov approach, …