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Articles 331 - 360 of 372
Full-Text Articles in Engineering
Experimental Test And Cost Analysis Of Residential Solar Water Heaters, Sai Mahesh Dharanikota
Experimental Test And Cost Analysis Of Residential Solar Water Heaters, Sai Mahesh Dharanikota
ETD Archive
Non renewable energy sources have been diminishing in the recent times.Renewable energy is abundant in nature, but the use of it is very low.Lowering the energy consumption and using renewable energy, thereby decreasing the use of fossil fuels and nuclear energy would have a positive impact on our environment. The use of solar energy as an alternate resource is discussed in this research. The solar water heater is tested for its recovery rates, under normal solar radiation in static testing. The effect of solar radiation in increasing the temperature of water is studied and discussed. The solar water heater is …
Effect Of Adding A Regenerator To Kornhauser's Mit "Two-Space" Test Rig, Praveen Gidugu
Effect Of Adding A Regenerator To Kornhauser's Mit "Two-Space" Test Rig, Praveen Gidugu
ETD Archive
A 3-space solution domain (gas spring + heat exchanger + regenerator) is adapted from the 2-space solution domain (gas spring + heat exchanger) in Kornhauser MIT test rig [25] by modifying the heat exchanger space to include a porous regenerator system. A thermal non-equilibrium porous-media model is employed for the regenerator. Extensive numerical simulations of the fluid flow and heat transfer phenomena under conditions of oscillating pressure and oscillating fluid flow inside the 3-space solution domain were performed using 1-D Sage and 2-D Fluent numerical codes. 3-space results of temperature, pressure and surface heat transfer variations, pressure-volume diagrams, energy conservation …
Radiation View Factors Between A Disk And The Interior Of A Class Of Axisymmetric Bodies Including Converging Diverging Rocket Nozzles, Mark Richard Murad
Radiation View Factors Between A Disk And The Interior Of A Class Of Axisymmetric Bodies Including Converging Diverging Rocket Nozzles, Mark Richard Murad
ETD Archive
A general symbolic exact analytic solution is developed for the radiation view factors including shadowing by the throat between a divergence thin gas disk between the combustion chamber and the beginning of the rocket nozzle radiating energy to the interior downstream of the nozzle contour for a class of coaxial axisymmetric converging diverging rocket nozzles. The radiation view factors presented in this thesis for the projection which are blocked or shadowed through the throat radiating downstream to the contour have never been presented before in the literature. It was found that the curvature of the function of the contour of …
Application Of Reverse Engineering And Rapid Prototyping To Casting, Venkat Deepak Kolar
Application Of Reverse Engineering And Rapid Prototyping To Casting, Venkat Deepak Kolar
ETD Archive
The automotive industry has an increasing need for the re manufacturing of spare parts through reverse engineering. In this thesis we will review the techniques used in Fused Deposition Modeling system for the reverse engineering of vintage automotive parts. The objective of the project is to be able to generate part-to-CAD and CAD-to-part reconstruction of the original part for future usage. These newly created 3D models will be added to the 3D Part Database. The integration of reverse engineering and rapid prototyping is being used for getting product to the market quickly by resolving a long-standing conflict between design and …
Experimental Testing And Performance Analysis Of "Room Air Cleaners", Pavan Kumar Mudiya
Experimental Testing And Performance Analysis Of "Room Air Cleaners", Pavan Kumar Mudiya
ETD Archive
HMI industries are the manufacture of the air cleaners and vacuum cleaners, in which a solution is adapted for the current model of the volute to the new design of the volute in order to calculate the "Clean Air Delivery rate" and qualify for the "Energy Star requirements". For the above model to be employed as a Energy Star certificate, a test rig was made in which "air velocity" and "flow rate" was calculated for the three different air cleaners in two cases i.e. (i) three different air cleaners with different filters and different rpm's (ii) three different air cleaners …
Probabilistic Finite Element Heat Transfer And Structural Analysis Of A Cone-Cylinder Pressure Vessel, Omar Haddad
Probabilistic Finite Element Heat Transfer And Structural Analysis Of A Cone-Cylinder Pressure Vessel, Omar Haddad
ETD Archive
Stress analysis of a cone-cylinder pressure vessel was computationally simulated by a finite element method and probabilistically evaluated in view of the several uncertainties in the performance parameters. Cumulative distribution functions and sensitivity factors were computed for overall Von Mises stresses due to the structural and thermodynamic random variables. These results can be used to quickly identify the most critical design variables in order to optimize the design and make it cost effective. The analysis leads to the selection of the appropriate measurements to be used in structural and heat transfer analysis and to the identification of both the most …
Mathematical Analysis Of A Geothermal System, Ivan P. Erceg
Mathematical Analysis Of A Geothermal System, Ivan P. Erceg
ETD Archive
The issue being examined is to design a more economical and efficient therefore superior geothermal system than currently in use in industry. Current geothermal systems are designed and built 300 feet into the ground. After researching ground temperature gradients for Ohio we found out that below 10 feet of depth, the temperature varies by 1 degree Fahrenheit per 100 feet depth. Our goal is to utilize the heat as close to the surface as possible and greatly reduce the need to dig so deeply into the ground. The procedure used to go about designing a superior geothermal system is to …
Convolutional Coded Generalized Direct Sequence Spread Spectrum, Madan Venn
Convolutional Coded Generalized Direct Sequence Spread Spectrum, Madan Venn
ETD Archive
In this thesis we investigate the worst-case performance of coded ordinary and coded generalized direct sequence spread spectrum (DSSS) systems in a communication channel corrupted by an unknown and arbitrary interfering signal of bounded power. We consider convolutional codes with Viterbi decoding in order to compare the performance of coded ordinary and coded generalized DSSS systems. For the generalized DSSS system, we use a pulse stream of +1,-1 and 0 as the spreading sequence, which is different from ordinary DSSS system which uses the typical sequence with pulse values of +1 and -1. A C program for performing Monte-Carlo simulations …
Comparison Of Methods For Developing Estimated Parameter̄X Control Charts Propsed By Nedumaran & Pignatiello, Albers & Kallenberg And Tsai Et Al., Ozlem Temiz
ETD Archive
The subject of this thesis is the comparison of the development method used to determine the value of Xbar control chart limits when the underlying process parameters are unknown and must be estimated from data obtained from a Phase I historical samples. I propose in the research for this thesis to compare these three proposed methods in detail comparing their performance by developing empirical probability of signal distributions for both in-control and out-of-control situations. Generation of these distributions will be accomplished through discrete simulation. The final result will consist of recommendations concerning the best of the methods to use in …
Road Surface Condition Detection And Identification And Vehicle Anti-Skid Control, Maosheng Ye
Road Surface Condition Detection And Identification And Vehicle Anti-Skid Control, Maosheng Ye
ETD Archive
Road surface condition is greatly dependent on the surface's friction coefficient. The abrupt change of the coefficient results in variation of wheel slip which likely leads to vehicle instability. Vehicle steering model and the dynamic equations for four-wheel drive vehicle is developed. A new observer, called Extended State Observer (ESO) is used to estimate the longitudinal velocity, lateral velocity and yaw rate, and more importantly an additional quantity known as system dynamics. A trained neural network was employed to help determine the friction coefficient. Fuzzy logic was employed to quickly detect the change of road surface condition and further classify …
High Intensity Laser Power Beaming For Wireless Power Transmission, Daniel Edward Raible
High Intensity Laser Power Beaming For Wireless Power Transmission, Daniel Edward Raible
ETD Archive
This paper describes work supporting the development of a high intensity laser power beaming (HILPB) system for the purpose of wireless power transmission. The main contribution of this research is utilizing high intensity lasers to illuminate vertical multi-junction (VMJ) solar cells developed by NASA-GRC. Several HILPB receivers are designed, constructed and evaluated with various lasers to assess the performance of the VMJ cells and the receiver under a variety of conditions. Several matters such as parallel cell back-feeding, optimal receiver geometry, laser wavelength, non-uniform illumination and thermal effects at high intensities are investigated. Substantial power densities are achieved, and suggestions …
A Kinematics Based Tolerance Analysis Of Mechanisms, Shahrbanoo Biabnavi Farkhondeh
A Kinematics Based Tolerance Analysis Of Mechanisms, Shahrbanoo Biabnavi Farkhondeh
ETD Archive
A kinematic based tolerance analysis of mechanisms is presented in this thesis. It is shown that standard kinematic analysis can be used for obtaining closed-form explicit formulations for tolerance analysis of mechanisms. It is proposed that the manufacturing tolerances are accounted for by incorporating fictitious sliding members in the rigid links, thereby allowing them to either "grow" or "shrink" along the lines of their pin connections. The virtual expansions or contractions of these fictitious sliders are captured in the kinematic equations by taking the differentials of the magnitudes of the vectors that define the length of rigid links having dimensional …
Modeling Of Transient Thrust Of A Two Phase Propellant Tank, Karthik Mellechervu
Modeling Of Transient Thrust Of A Two Phase Propellant Tank, Karthik Mellechervu
ETD Archive
This thesis develops a model to predict various time-varying quantities associated with the evacuation of a pressurized container through a nozzle. The container is part of a satellite propulsion prototype used to study attitude control. Variables of interest include the thrust and mass of fluid in the tank as functions of time. A mathematical model based on transient expressions for mass and energy conservation is derived for a two-phase system representative of the conditions of the fluid inside the tank
Multiplexed Control Of Smart Structure Using Piezoelectric Actuators, Kumar S. Nale
Multiplexed Control Of Smart Structure Using Piezoelectric Actuators, Kumar S. Nale
ETD Archive
Active control of smart structures containing a large number of actuators and sensors presents a tradeoff between increased system performance and the cost and bulk of the required hardware and computational resources. A technique called multiplexed control offers advantages when software and hardware resources are scarce and performance specifications call for a large number of actuators and sensors. In structural control applications, in particular those using smart materials, it is often desirable to increase the number of actuators to enhance controllability.The focus of this research is to demonstrate real-time multiplexing on the hardware side of the actively controlled structure. Multiplexing …
Effect Of Axial Oscillation On Performance Of Hydrodynamic Journal Bearings, Thomas Wirsing
Effect Of Axial Oscillation On Performance Of Hydrodynamic Journal Bearings, Thomas Wirsing
ETD Archive
The hydrodynamic coefficients of a journal bearing set with the bearing subjected to axial oscillation are determined in this work. The Navier-Stokes equations were used to account for the axial component of the relative motion between the journal and the bearing. Numerical solution of the Navier-Stokes equations yielded the pressure distribution within the cavity of the bearing. This pressure distribution was then integrated over the surface of the bearing to obtain the two orthogonal force components. The derivatives of these force components were then taken with respect to the displacement and velocity of the journal that are co-linear with these …
Motion Control Of An Open Container With Slosh Constraints, Kedar B. Karnik
Motion Control Of An Open Container With Slosh Constraints, Kedar B. Karnik
ETD Archive
General motion control of conveyor belts does not present difficulties. When the conveyor belt carries open containers filled with liquid, significant analysis needs to be carried out to design controllers. The objective of this thesis was to design a control system which will allow an open container filled with liquid to be transferred between two stations as fast as possible and without excessive slosh causing the liquid to spill out of the container. This control problem has applications to industrial processing facilities, where open containers are carried by a conveyor belt. The speed at which the open container can be …
Development Of Effective Balancing Procedure For Ct Scanner, Jeremy David Pettinato
Development Of Effective Balancing Procedure For Ct Scanner, Jeremy David Pettinato
ETD Archive
Since the beginning of medical organizations, engineering departments have introduced new innovative ideas and designs to advance image quality. In the case of a CT scanner, one of the largest and most cost effective ways to achieve superior image quality is through a well balanced rotating array. The focus of this thesis is the development of a balancing procedure which will effectively balance a CT scanner rotating array. Rigid rotor (dynamic) balancing techniques are utilized in order to balance the Philips CT scanner rotor. Upon completion of the dynamic balancing of the CT scanner rotor a new an innovative way …
Health Monitoring Of Cracked Rotor Systems Using External Excitation Techniques, Adam C. Wróblewski
Health Monitoring Of Cracked Rotor Systems Using External Excitation Techniques, Adam C. Wróblewski
ETD Archive
Cracked rotors present a significant safety and loss hazard in nearly every application of modern turbomachinery. This thesis focuses on the health monitoring, modeling, and analysis of machines with transverse breathing cracks, which open and close due to the self-weight of the rotor. After considering the modeling of cracked rotors, the thesis investigates an active structural health monitoring approach, focusing on the application of an active magnetic actuator to apply a specially designed external force excitation to the rotating shaft. Extensive experimental data has been collected and analyzed utilizing advanced diagnostic techniques. The presented results demonstrate that the use of …
Damage Detection Of Rotors Using Magnetic Force Actuator: Analysis And Experimental Verification, Alexander Hans Pesch
Damage Detection Of Rotors Using Magnetic Force Actuator: Analysis And Experimental Verification, Alexander Hans Pesch
ETD Archive
The ability to monitor the structural health of rotordynamic systems is becoming increasingly important as critical components continue to be used despite aging and the associated potential for damage accumulation. The aim of this thesis is to investigate a novel structural health monitoring approach for the detection of damage in rotating shafts, which utilizes a magnetic force actuator for applying multiple types of force inputs on to a rotating structure for analysis of resulting outputs. The magnetic actuator will be used in conjunction with conventional support bearings and also be applied to rotor under full magnetic levitation. The results of …
A Wrapper-Based Approach To Sustained Time Synchronization In Wireless Sensor Networks, Dheeraj Reddy Bheemidi
A Wrapper-Based Approach To Sustained Time Synchronization In Wireless Sensor Networks, Dheeraj Reddy Bheemidi
ETD Archive
Time synchronization is an important service for wireless sensor network applications. Nodes in the network stay synchronized by exchanging periodic messages that carry local timestamps. Several algorithms have been proposed in the literature that are suited to different kinds of application scenarios. A common problem across these time synchronization algorithms is that the energy cost of message exchange is high. In fact, the cost of radio communication far outstrips the cost of performing local operations on the processor. If the message exchanges were stopped, nodes will fall out of sync, and may no longer be able to meet application requirements. …
A Sensor Network System For Monitoring Short-Term Construction Work Zones, Manohar Bathula
A Sensor Network System For Monitoring Short-Term Construction Work Zones, Manohar Bathula
ETD Archive
Safety hazards encountered near construction work zones are high, both in number and in the kind. There is a need to monitor traffic in such construction zones in order to improve driver and vehicle safetyIn the past traffic monitoring systems were built with high cost equipment such as inductive plates, video cameras etc. These solutions are too cost{prohibitive and invasive to be used in the large. Wireless sensor networks provide an opportunity space that can be used to address this problem. This thesis specifically targets temporary or short-term construction work zones. We present the design and implementation of a sensor …
Dspace Implementation Of A Generalized Method Of Harmonic Elimination For Pwm Boost Type Rectifier Under Unbalanced Operating Conditions, Ke Chen
ETD Archive
In this thesis, the implementation of a generalized method of harmonic elimination for the PWM boost type rectifier under severe fault conditions in the power system is presented. This method has been implemented by using DSPACE RT1104 digital control system. Control loop has been designed for real-time DC link voltage regulation. The simulation and experimental results verify the feasibility of the control scheme for input-output harmonic elimination. With the proposed method, unity power factor can be achieved as well as low-order harmonic elimination. High quality input and output waveforms of the three-phase PWM boost type rectifier are obtained under extremely …
Slurry Based Coatings On Silicon Based Ceramics, Sameer K. Khaja-Abdul
Slurry Based Coatings On Silicon Based Ceramics, Sameer K. Khaja-Abdul
ETD Archive
The use of advanced structural ceramics, such as Si3N4 (SN282), SiC, and SiC/SiC composites, is a promising technology to accomplish the high performance goals for advanced turbine applications. These materials exhibit excellent corrosion resistance by forming a dense silica scale. However, severe degradation of the silica scale has been observed due to the presence of certain environmental species, like alkali salts and water vapors, limiting the long-term reliability of structural ceramics. Presence of water vapor in the turbine environment leads to the formation of a gaseous silicon hydroxide species (Si(OH)4) via a reaction with silica layer, SiO2(s) + 2H2O(g) = …
Nonlinear State Estimation In Polymer Electrolyte Membrane Fuel Cells, Uma Tumuluri
Nonlinear State Estimation In Polymer Electrolyte Membrane Fuel Cells, Uma Tumuluri
ETD Archive
Research on alternative and renewable energy sources which are amicable to the environment has gained momentum because of the growing concern about the tremendous increase in the concentration of toxic and green house gases and scarcity of the fossil fuels. Among the available renewable sources, fuel cell technology has received a high research attention due to their high efficiency and superior reliability. Among the various fuel cells available, Polymer electrolyte membrane fuel cell is promising source for both stationary and mobile applications because of its high efficiency and low operating temperatures. The performance of the fuel cell depends on the …
A Novel Cascaded Multilevel Converter, Rajmohan Rangarajan
A Novel Cascaded Multilevel Converter, Rajmohan Rangarajan
ETD Archive
A novel cascaded multilevel converter is proposed in this thesis. The thesis proposes to produce more voltage levels from fewer H-bridges in a cascaded multilevel converter. The converter uses fewer H-bridges and the proposed switching scheme renders more voltage level in the staircase waveform with equal steps. Since the resulting voltage levels are equal, the angles are determined for the complete elimination of more unwanted harmonics. The implementation of the switching scheme, in single and three-phase configurations were simulated with Ansoft Simplorer♭ and the frequency spectrum of the resulting waveform and its total harmonic distortion are shown to verify the …
Byzantine Fault Tolerance For Nondeterministic Applications, Bo Chen
Byzantine Fault Tolerance For Nondeterministic Applications, Bo Chen
ETD Archive
The growing reliance on online services accessible on the Internet demands highly reliable system that would not be interrupted when encountering faults. A number of Byzantine fault tolerance (BFT) algorithms have been developed to mask the most complicated type of faults - Byzantine faults such as software bugs,operator mistakes, and malicious attacks, which are usually the major cause of service interruptions. However, it is often difficult to apply these algorithms to practical applications because such applications often exhibit sophisticated non-deterministic behaviors that the existing BFT algorithms could not cope with. In this thesis, we propose a classification of common types …
High Strength E-Glass/Cnf Fibers Nanocomposite, Esam Abu-Zahra
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
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
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
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 …