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Articles 61 - 86 of 86
Full-Text Articles in Engineering
A Systems Engineering Reference Model For Fuel Cell Power Systems Development, T. L. Blanchard
A Systems Engineering Reference Model For Fuel Cell Power Systems Development, T. L. Blanchard
ETD Archive
This research was done because today the Fuel Cell (FC) Industry is still in its infancy in spite over one-hundred years of development has transpired. Although hundreds of fuel cell developers, globally have been spawned, in the last ten to twenty years, only a very few are left struggling with their New Product Development (NPD). The entrepreneurs of this type of disruptive technology, as a whole, do not have a systems engineering 'roadmap", or template, which could guide FC technology based power system development efforts to address a more environmentally friendly power generation. Hence their probability of achieving successful commercialization …
Fea Analysis Of Novel Design Of Cylindrical Roller Bearing, Prasanna Subbarao Bhamidipati
Fea Analysis Of Novel Design Of Cylindrical Roller Bearing, Prasanna Subbarao Bhamidipati
ETD Archive
This work presents a finite element stress analysis of a novel design of cylindrical roller. The focus of this study is to create a uniform contact-stress distribution along the length of the roller and to recommend a roller bearing design which is easier to fabricate. The new design relies on creating symmetric cylindrical cavities at both ends of a roller. The cavity is concentric with the main body of the roller. The new roller design reduces overall mass of the typical assembly with helps to improve bearing life and its overall performance. The FEA results published herein shows that new …
Vibratory Behavior Of Rolling Element Bearings: A Lagrangian Approach, Phani Krishna Kalapala
Vibratory Behavior Of Rolling Element Bearings: A Lagrangian Approach, Phani Krishna Kalapala
ETD Archive
Vibratory behavior of a rolling element bearing on a horizontal rotor is studied in this work. This Thesis analyzes the dynamics of a typical roller bearing as a result of internal excitations. These internal excitations stem from the geometric deviations of the interacting surfaces from their ideal geometry. Such deviations in turn are the results of either manufacturing limitations or normal wear of the bearing surfaces. Lagrangian approach is implemented to derive the dynamic equations of motion. Matlab is used to solve the equation of motion of governing the vibrations of the system. Parametric studies are conducted to provide results …
Adaptive Sliding Mode Control For Aircraft Engines, Kathryn C. Ebel
Adaptive Sliding Mode Control For Aircraft Engines, Kathryn C. Ebel
ETD Archive
Aircraft engine control has been evolving since its beginning. With advancements in technology more and more control methods are being applied to this area. This thesis presents the design of an adaptive PID sliding mode control (A-SMC) for a turbofan engine. The controller design methodology is presented. Using an aircraft engine simulation environment developed by NASA, called Commercial Modular Aero-Propulsion System Simulation, the developed controller is tested. The results from three simulations are analyzed to investigate the application of this new design scheme. The A-SMC is able to follow the demanded fan speed for short flight simulations. However, some of …
Multivariable Sliding Mode Control Design For Aircraft Engines, Sirirat Sangwian
Multivariable Sliding Mode Control Design For Aircraft Engines, Sirirat Sangwian
ETD Archive
Many control theories are used in controlling aircraft engines. However, the multivariablesliding mode control is not yet established in this application even though ithas a lot of potential in dealing with complex and nonlinear systems such as aircraftengines. Therefore, a guideline in developing multivariable sliding mode control law for an aircraft engine is presented in this thesis. The problem of chattering in thesliding mode control is suppressed by the use of the boundary layer method. The controllogic is tested by implementing NASA's Commercial Modular Aero-PropulsionSystem Simulation 40k (C-MAPSS40k). Simulation results are analyzed and comparedto the results obtained from the baseline …
Investigations Of Anatomical Connectivity In The Internal Capsule Of Macaques With Diffusion Magnetic Resonance Imaging, Kyle Andrew Ignatius Taljan
Investigations Of Anatomical Connectivity In The Internal Capsule Of Macaques With Diffusion Magnetic Resonance Imaging, Kyle Andrew Ignatius Taljan
ETD Archive
Understanding anatomical connectivity is crucial for improving outcomes of deep brain stimulation surgery. Tractography is a promising method for noninvasively investigating anatomical connectivity, but connections between subcortical regions have not been closely examined by this method. As many connections to subcortical regions converge at the internal capsule (IC), we investigate the connectivity through the IC to three subcortical nuclei (caudate, lentiform nucleus, and thalamus) in 6 macaques. We show that a statistical correction for a known distance-related artifact in tractography results in large changes in connectivity patterns. Our results suggest that care should be taken in using tractography to assess …
Modeling And Performance Investigation Of A Rotor With Dissimilar Bearing Support System, Yunlu Li
Modeling And Performance Investigation Of A Rotor With Dissimilar Bearing Support System, Yunlu Li
ETD Archive
Different types of bearings have different dynamic characteristics. By using one type of bearing at one end of a rotor and another type of bearing at the other end of the rotor, it is possible to exploit the advantages of both types in the same system. One example of such combination is a bronze bushing and active magnetic bearing (AMB). In the available literature, there are examples of such systems but are not fully explored with regard to how to model the system to fully utilize both support type properties. This thesis investigates the modeling and performance of such a …
A Left Ventricular Motion Phantom For Cardiac Magnetic Resonance Imaging, Mehmet Ersoy
A Left Ventricular Motion Phantom For Cardiac Magnetic Resonance Imaging, Mehmet Ersoy
ETD Archive
The mammalian left ventricle (LV) has two distinct motion patterns: wall thickening and rotation. The purpose of this study was to design and build a low-cost, non-ferromagnetic LV motion phantom, for use with cardiac magnetic resonance imaging (MRI), that is able to produce physiologically realistic LV wall thickening and rotation. Cardiac MRI is continuously expanding its range of techniques with new pulse sequences, including new tissue tagging techniques which allow intra-myocardial deformation to be visualized. An essential step in the development of new cardiac MRI techniques is validating their performance in the presence of motion. MRI-compatible dynamic motion phantoms are …
Assessment Of Circumferential Myocardial Function Using Radial Tagged Mri, Yujaung Kim
Assessment Of Circumferential Myocardial Function Using Radial Tagged Mri, Yujaung Kim
ETD Archive
The extent of myocardial abnormalities is related to cardiac disease. The assessment of myocardial function of the left ventricular (LV) described by the LV myocardial deformation plays an important role to understand the effects of cardiovascular disease and therapeutic interventions on LV motion. Cardiac magnetic resonance imaging (CMR) is widely agreed as the most accurate noninvasive imaging modality for the assessment of left ventricular (LV) function. In addition, myocardial-tagging technique can track the myocardial deformation by labeling specific regions. Although the grid tagging is popular in cardiac research use, it has not been adopted into routine clinical examination with unreliable …
Intelligent Controls For A Semi-Active Hydraulic Prosthetic Knee, Timothy Allen Wilmot
Intelligent Controls For A Semi-Active Hydraulic Prosthetic Knee, Timothy Allen Wilmot
ETD Archive
We discuss open loop control development and simulation results for a semi-active above-knee prosthesis. The control signal consists of two hydraulic valve settings. These valves control a rotary actuator that provides torque to the prosthetic knee. We develop open loop control using biogeography-based optimization (BBO), which is a recently developed evolutionary algorithm, and gradient descent. We use gradient descent to show that the control generated by BBO is locally optimal. This research contributes to the field of evolutionary algorithms by demonstrating that BBO is successful at finding optimal solutions to complex, real-world, nonlinear, time varying control problems. The research contributes …
A Concept For Direct Control Of Rotary Blood Pump Speed By Inlet Pressure, Ibrahim Seven
A Concept For Direct Control Of Rotary Blood Pump Speed By Inlet Pressure, Ibrahim Seven
ETD Archive
Heart failure remains a major health problem for the world. Heart transplantation is the most effective treatment for end stage heart failure. A major problem with heart transplantation is finding adequate numbers of appropriate donors. The lack of donor numbers in the world creates a significant clinical need for blood pumping devices. The ability of ventricular assist devices to relieve the consequences of less than terminal heart failure further creates a need for assist therapy. Current new ventricular assist devices are built around continuous flow technology. These nonpulsatile assist devices have had major clinical success in relieving symptoms and increasing …
Application Of Active Magnetic Force Actuator For Control Of Flexible Rotor System Vibrations, Volodymyr Mykhaylyshyn
Application Of Active Magnetic Force Actuator For Control Of Flexible Rotor System Vibrations, Volodymyr Mykhaylyshyn
ETD Archive
The purpose of this work was to develop and experimentally demonstrate a novel approach to minimize lateral vibrations of flexible rotor. The applied feed forward control approach employed magnetic force actuator to inject a specially designed force to counteract the rotor unbalance force. By specific selection of frequency and phase as functions of the rotor running speed and rotor natural frequency, the proposed simplified injection waveform has been shown to be effective both in reducing the rotor's vibrations and for hardware implementation. A model of the test rig was constructed using the finite element (FE) method and was validated using …
The Relational Database: A New Static Analysis Tool?, Adam M. Dutko
The Relational Database: A New Static Analysis Tool?, Adam M. Dutko
ETD Archive
Code comprehension is pivotal to reducing errors in software. Reading source code improves code comprehension and enables effective fixes but as a code base grows meta-data become increasingly important. Static Analysis techniques provide an avenue for software developers to learn more about their code through meta-data while also helping them safely detect potential errors in their source. Unfortunately, many Static Analysis tools have a steep learning curve and are limited in scope. This thesis seeks to make Static Analysis accessible and extensible by asking what ubiquitous tools like SQL and relational databases can offer and what they cannot. We begin …
Efficient Time Of Arrival Calculation For Acoustic Source Localization Using Wireless Sensor Networks, Prashanth G. Reddy
Efficient Time Of Arrival Calculation For Acoustic Source Localization Using Wireless Sensor Networks, Prashanth G. Reddy
ETD Archive
Acoustic source localization is a very useful tool in surveillance and tracking applications. Potential exists for ubiquitous presence of acoustic source localization systems. However, due to several significant challenges they are currently limited in their applications. Wireless Sensor Networks (WSN) offer a feasible solution that can allow for large, ever present acoustic localization systems. Some fundamental challenges remain. This thesis presents some ideas for helping solve the challenging problems faced by networked acoustic localization systems. We make use of a low-power WSN designed specifically for distributed acoustic source localization. Our ideas are based on three important observations. First, sounds emanating …
Effect Of Step Change In Growth Speed During Directional Solidification On Array Morphology Of Al-7 Wt Si Alloy, Swapna Pakiru
Effect Of Step Change In Growth Speed During Directional Solidification On Array Morphology Of Al-7 Wt Si Alloy, Swapna Pakiru
ETD Archive
No abstract provided.
Measuring The Environmental Impact Of Embedded/Bankfull Culverts, Joseph A. Pavlick
Measuring The Environmental Impact Of Embedded/Bankfull Culverts, Joseph A. Pavlick
ETD Archive
Streams are dynamic systems constantly changing over time. The health of a stream system is tied to the amount of sedimentation occurring in a stream. The addition of roadway culverts into a stream has been shown to cause erosion and sedimentation problems if the culvert does not meet stream characteristics of slope, bankfull/width, and channel orientation. This has led to the design of embedded/bankfull culverts. In the State of Ohio, the Ohio Environmental Protection Agency and the United States Army Corps of Engineers now require the Ohio Transportation to install embedded/bankfull culverts at all stream locations during new roadway construction. …
Implementing A Piezoelectric Transformer For A Ferroelectric Phase Shifter Circuit, Anthony M. Roberts
Implementing A Piezoelectric Transformer For A Ferroelectric Phase Shifter Circuit, Anthony M. Roberts
ETD Archive
No abstract provided.
Measurement Of White Matter Structure Changes In Amyotrophic Lateral Sclerosis Using Fractal Analysis, Zao Liu
ETD Archive
Amyotrophic lateral sclerosis (ALS) is recognized as a motor neuron disorder affecting the structure and function of the brain and neuromuscular system. Very little is known, however, that the nervous system degeneration is dependent on disease phenotypes of ALS. The purpose of this study was to determine the degree of brain white matter (WM) structure degeneration in four ALS patient groups characterized by their clinical signs and neuroimaging measurements. Fractal dimension (FD) of three-dimensional (3D) brain WM images was quantitatively analyzed to evaluate the WM structural complexity, including complexity levels of the WM skeleton, surface and general structures in ALS …
Implementation Of An Advanced Controller On A Torsional Mechanism, Chintan Trivedi
Implementation Of An Advanced Controller On A Torsional Mechanism, Chintan Trivedi
ETD Archive
The hardware implementation of an active disturbance rejection controller (ADRC) is presented in the thesis for a mechanical torsional plant. ADRC is a novel disturbance rejection control technique that is not completely dependent on mathematical models of physical systems. In ADRC framework external disturbances, system uncertainties, and internal dynamics of the system are estimated as a generalized disturbance by an extended state observer and the generalized disturbance is effectively canceled by a PD controller. A torsional plant represents a class of rotational systems. Its control challenges are the vibrations caused by mass imbalance, centrifugal imbalance, and the imbalance caused by …
Dye Waste Treatment, Siew Teng Ong, Pei Sin Keng, Weng Nam Lee, Sie Tiong Ha, Yung Tse Hung
Dye Waste Treatment, Siew Teng Ong, Pei Sin Keng, Weng Nam Lee, Sie Tiong Ha, Yung Tse Hung
Civil and Environmental Engineering Faculty Publications
© 2011 by the authors. Dye wastes represent one of the most problematic groups of pollutants because they can be easily identified by the human eye and are not easily biodegradable. This literature review paper highlights and provides an overview of dye waste treatments performed over the three years period from 2008-2010. Noteworthy processes for the treatment of dye waste include biological treatment, catalytic oxidation, filtration, sorption process and combination treatments.
A Dynamic System Model Of Biogeography-Based Optimization, Daniel J. Simon
A Dynamic System Model Of Biogeography-Based Optimization, Daniel J. Simon
Electrical and Computer Engineering Faculty Publications
We derive a dynamic system model for biogeography-based optimization (BBO) that is asymptotically exact as the population size approaches infinity. The states of the dynamic system are equal to the proportion of each individual in the population; therefore, the dimension of the dynamic system is equal to the search space cardinality of the optimization problem. The dynamic system model allows us to derive the proportion of each individual in the population for a given optimization problem using theory rather than simulation. The results of the dynamic system model are more precise than simulation, especially for individuals that are very unlikely …
Implicit Methods For Efficient Musculoskeletal Simulation And Optimal Control, Antonie J. Van Den Bogert, Dimitra Blana, Dieter Heinrich
Implicit Methods For Efficient Musculoskeletal Simulation And Optimal Control, Antonie J. Van Den Bogert, Dimitra Blana, Dieter Heinrich
Mechanical Engineering Faculty Publications
The ordinary differential equations for musculoskeletal dynamics are often numerically stiff and highly nonlinear. Consequently, simulations require small time steps, and optimal control problems are slow to solve and have poor convergence. In this paper, we present an implicit formulation of musculoskeletal dynamics, which leads to new numerical methods for simulation and optimal control, with the expectation that we can mitigate some of these problems. A first order Rosenbrock method was developed for solving forward dynamic problems using the implicit formulation. It was used to perform real-time dynamic simulation of a complex shoulder arm system with extreme dynamic stiffness. Simulations …
Robotic Testing Of Proximal Tibio-Fibular Joint Kinematics For Measuring Instability Following Total Knee Arthroplasty, Wael K. Barsoum, Ho H. Lee, Trevor G. Murray, Robb Colbrunn, Alison K. Klika, S. Butler, Antonie J. Van Den Bogert
Robotic Testing Of Proximal Tibio-Fibular Joint Kinematics For Measuring Instability Following Total Knee Arthroplasty, Wael K. Barsoum, Ho H. Lee, Trevor G. Murray, Robb Colbrunn, Alison K. Klika, S. Butler, Antonie J. Van Den Bogert
Mechanical Engineering Faculty Publications
Pain secondary to instability in total knee arthroplasty (TKA) has been shown to be major cause of early failure. In this study, we focused on the effect of instability in TKA on the proximal tibio-fibular joint (PTFJ). We used a robotics model to compare the biomechanics of the PTFJ in the native knee, an appropriately balanced TKA, and an unbalanced TKA. The tibia (n = 5) was mounted to a six-degree-of-freedom force/torque sensor and the femur was moved by a robotic manipulator. Motion at the PTFJ was recorded with a high-resolution digital camera system. After establishing a neutral position, …
Activated Sludge And Other Aerobic Suspended Culture Processes, Charles J. Moretti, Dipesh Das, Brian T. Kistner, Harvey Gullicks, Yung Tse Hung
Activated Sludge And Other Aerobic Suspended Culture Processes, Charles J. Moretti, Dipesh Das, Brian T. Kistner, Harvey Gullicks, Yung Tse Hung
Civil and Environmental Engineering Faculty Publications
© 2011 by the authors. A review of the literature published in 2008, 2009 and 2010 relating to activated sludge treatment of wastewater is presented. The review considers information on the topics of modeling and kinetics; process microbiology; nitrogen and phosphorus removal; treatment and effects of xenobiotics; oxygen transfer; and solids separation.
Biofilm Fixed Film Systems, Harvey Gullicks, Hasibul Hasan, Dipesh Das, Charles Moretti, Yung Tse Hung
Biofilm Fixed Film Systems, Harvey Gullicks, Hasibul Hasan, Dipesh Das, Charles Moretti, Yung Tse Hung
Civil and Environmental Engineering Faculty Publications
© 2011 by the authors. The work reviewed here was published between 2008 and 2010 and describes research that involved aerobic and anoxic biofilm treatment of water pollutants. Biofilm denitrification systems are covered when appropriate. References catalogued here are divided on the basis of fundamental research area or reactor types. Fundamental research into biofilms is presented in two sections, Biofilm Measurement and Characterization and Growth and Modeling. The reactor types covered are: trickling filters, rotating biological contactors, fluidized bed bioreactors, submerged bed biofilm reactors, biological granular activated carbon, membrane bioreactors, and immobilized cell reactors. Innovative reactors, not easily classified, are …
Chemicals And Allied Products Waste Treatment, Yung Tse Hung, Erick Butler, Ruth Yu-Li Yeh
Chemicals And Allied Products Waste Treatment, Yung Tse Hung, Erick Butler, Ruth Yu-Li Yeh
Civil and Environmental Engineering Faculty Publications
© 2011 by the authors. A review of the literature published from 2008 to 2010 on topics related to chemicals and allied products is presented. The review considered several sections such as waste management, physicochemical treatment, aerobic treatment, anaerobic treatment, air emissions, soils and groundwater, and reuse.