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Full-Text Articles in Engineering

High Strength E-Glass/Cnf Fibers Nanocomposite, Esam Abu-Zahra Jan 2007

High Strength E-Glass/Cnf Fibers Nanocomposite, Esam Abu-Zahra

ETD Archive

Glass fibers are among the most versatile industrial materials known today, where 4 billion pounds of glass are used every year. They are readily produced from raw materials, which are available in virtually unlimited supply. To compensate for its low tensile strength, glass is usually mixed with other materials such as nanofibers and nanospheres, to form what is called "glass nanocomposites". Nevertheless, glass composites still suffer from different weaknesses such as: poor dispersion, poor alignment and orientation of reinforcing materials (due to their short lengths relative to the defect sizes in the composite matrices), in addition to the difficulties associated …


An Investigation Of The Relationship Between Dermal Stresses And Foot Ground Stresses In Diabetic Patients, Zaid M. Hasasneh Jan 2007

An Investigation Of The Relationship Between Dermal Stresses And Foot Ground Stresses In Diabetic Patients, Zaid M. Hasasneh

ETD Archive

The number of people diagnosed with diabetes in the U.S. has been showing a large increase. It has more than doubled during the period of 1980 to 2002. Approximately 18 million Americans have diabetes today with more than 5.2 million undiagnosed cases. While diabetes is categorized as an endocrine system disorder, some of its known complications are associated to the science of biomechanics. Foot ulcers are caused by vascular deterioration due to diabetes, but also directly related to the natural mechanical forces and loads applied to the feet. Therefore, studying these forces, their locations, distribution and their stresses may be …


Hardware Implementation Of Active Disturbance Rejection Control For Vibrating Beam Gyroscope, David Avanesian Jan 2007

Hardware Implementation Of Active Disturbance Rejection Control For Vibrating Beam Gyroscope, David Avanesian

ETD Archive

Obtaining the approximation of rotation rate form a Z-Axis MEMS gyroscope is a challenging problem. Currently, most commercially available MEMS gyroscopes are operating in an open-loop for purposes of simplicity and cost reduction. However, MEMS gyroscopes are still fairly expensive and are not robust during operation. The purpose of this research was to develop a high-performance and low-cost MEMS gyroscope using analog Active Disturbance Rejection Control (ADRC) system. By designing and implementing analog ADRC both above requirements were satisfied. Analog ADRC provides the fastest response time possible (because the circuit is analog), eliminates both internal and external disturbances, and increases …


Robust And Decentralized Control Of Web Winding Systems, Wankun Zhou Jan 2007

Robust And Decentralized Control Of Web Winding Systems, Wankun Zhou

ETD Archive

This research addresses the velocity and tension regulation problems in web handling, including those found in the single element of an accumulator and those in the large-scale system settings. A continuous web winding system is a complex large-scale interconnected dynamics system with numerous tension zones to transport the web while processing it. A major challenge in controlling such systems is the unexpected disturbances that propagate through the system and affect both tension and velocity loops along the way. To solve this problem, a unique active disturbance rejection control (ADRC) strategy is proposed. Simulation results show remarkable disturbance rejection capability of …


Stirling Convertor Control For A Lunar Concept Rover, Gina Blaze Jan 2007

Stirling Convertor Control For A Lunar Concept Rover, Gina Blaze

ETD Archive

NASA Glenn Research Center is developing various circuits for a lunar concept rover powered by both a stirling convertor and lithium ion batteries. To begin, a survey of six analog, non-power factor correcting controllers was done for an Advanced Stirling Convertor (ASC) design one was selected to control the stirling convertor. Next, a constant power circuit and lithium ion battery charger was designed, built and tested based on simulation in PSpice. The constant power circuit enables the stirling convertor to maintain a constant power when additional power is required from the batteries


Treatment Of Wastewater Containing Phenol And Heavy Metals Using Natural Zeolite And Bioaugmentation, Patrick Brian Jameson Jan 2007

Treatment Of Wastewater Containing Phenol And Heavy Metals Using Natural Zeolite And Bioaugmentation, Patrick Brian Jameson

ETD Archive

No abstract provided.


Development And Control Of A Solar Array Switching Module, Joseph E. Rymut Jan 2007

Development And Control Of A Solar Array Switching Module, Joseph E. Rymut

ETD Archive

This research focuses on the development and control of a solar array switching module (SASM). The objective of studying this problem was to develop the SASM hardware and design a controller for the SASM which would effectively deal with the wide ranging dynamics of the system and limit oscillations in the steady state. Initially an intuitive controller was designed to control the SASM. Following this an analysis of the SASM was preformed to create a model which described the SASMs operation. Using the system model, an analysis of a PI and a PII controller was completed which found that both …


Mathematical Model Of Ethanol Metabolism In Liver, Parag Pande Jan 2007

Mathematical Model Of Ethanol Metabolism In Liver, Parag Pande

ETD Archive

A lumped mathematical model of liver metabolism is presented to analyze the effect of ethanol on metabolic processes of 24 hr fasted rats. The model is developed in two parts. In the first part individual kinetic models for important regulatory steps in the liver metabolic pathways are developed and in second part transport and mass balance equations in the two well mixed domains: tissue and blood, are developed to calculate intermediate metabolite concentrations and fluxes in response to the changes in ethanol and lactate concentrations in the perfusion medium. Part of the model without ethanol metabolism has been validated and …


Development And Modeling Of High Temperature Polymeric Heater, Maziyar Bolourchi Jan 2007

Development And Modeling Of High Temperature Polymeric Heater, Maziyar Bolourchi

ETD Archive

Polymers are generally known for their excellent insulative properties. The addition of carbonaceous fillers such as carbon black and graphite within a polymer matrix can impart electrical and thermal properties making them good conductors. The resulting composites can be used in applications requiring and/or ranging from electromagnetic and radio frequency interference (EMI/RFI) shielding, electrostatic discharge (ESD) and heaters/heating elements to which metals have been the materials of choice. The advantages of using such composites include cost reduction, part consolidation, chemical resistance, lighter weight, and ability to easily design into complex three dimensional shapes via injection molding. For this work, various …


Studying The Interaction Of Antifreeze Proteins (Type I And Type Iii) With The Phospholipid Monolayers At Air/Water Interface, Suresh Essampally Jan 2007

Studying The Interaction Of Antifreeze Proteins (Type I And Type Iii) With The Phospholipid Monolayers At Air/Water Interface, Suresh Essampally

ETD Archive

Heart transplantation is a successful therapeutic procedure for the patients with end stage heart disease. Various preservative techniques have been developed to increase the shelf life of organs, but still there can be tissue damage during cold storage. One mechanism leading to damage is disruption of cell plasma membranes as they pass through temperature induced phase transitions. The addition of antifreeze protein (AFP) or glycoprotein (AFGP) to storage solutions has been hypothesized to reduce the leakiness of lipid membranes. From studies using liposomes it has been shown that AFPs can prevent leakage through lipid membranes, although the mechanism of interaction …


Performance Characteristics Of An Innovative Wind Power System, David James Kerze Jan 2007

Performance Characteristics Of An Innovative Wind Power System, David James Kerze

ETD Archive

This project entails a study of a wind energy recovery system that utilizes a unique three-dimensional spiral structure to amplify wind speed and direct it toward pluralities of turbines. The system is comprised of an outer spiral shell, internal support structure, turbines, and mechanisms for positioning the turbines to face the prevailing wind. Computational Fluid Dynamics (CFD) analyses were conducted to determine the wind speed amplification factors as a result of a simulated wind flow around the spiral structure. To ensure accuracy of the results, state of the art CFD techniques were applied using Gambit 2.2.30 and Fluent 6.2.16. Specifically, …


Flow Of Sub-Cooled Cryogens Through A Joule-Thomson Device: Investigation Of Metastability Conditions, John M. Jurns Jan 2007

Flow Of Sub-Cooled Cryogens Through A Joule-Thomson Device: Investigation Of Metastability Conditions, John M. Jurns

ETD Archive

Cryogenic fluid systems are fundamental to space flight architecture. Due to the unique properties of cryogenic fluids and the environments in which they operate for space flight, cryogenic fluid management systems must be developed to maintain these fluids at conditions in which they can be utilized. Liquid oxygen boils at 90 K, and liquid hydrogen boils at 20 K. Significant care must be taken to provide a thermal management system that prevents heat entering these fluids with consequential adverse effects on the performance of the cryogenic fluid systems. One critical component of a cryogenic thermal management system is a Joule-Thomson …


Byzantine Fault Tolerant Coordination For Web Services Atomic Transactions, Honglei Zhang Jan 2007

Byzantine Fault Tolerant Coordination For Web Services Atomic Transactions, Honglei Zhang

ETD Archive

This thesis describes a Byzantine fault tolerant coordination framework for Web services atomic transactions. In the framework, all core services, including transaction activation, registration, completion, and distributed commit, are replicated and protected by Byzantine fault tolerance mechanisms. The traditional two-phase commit protocol is extended by a Byzantine fault tolerant version that can tolerate arbitrary faults on the coordinator and the initiator sides, and some types of malicious faults on the participant side. To achieve Byzantine fault tolerance in an efficient manner, and to limit the types of malicious behaviors of the coordinator, a novel decision certificate is introduced. The decision …