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Articles 1561 - 1590 of 3914
Full-Text Articles in Engineering
A Renewable Energy Feasibility Study To Power A Water Supply Pump In Sacala Las Lomas, Guatemala, William Anthony Granich
A Renewable Energy Feasibility Study To Power A Water Supply Pump In Sacala Las Lomas, Guatemala, William Anthony Granich
Masters Theses
"A clean and sufficient source of drinking water can be a challenge to develop in the rural highlands of Guatemala. Installing a submersible pump in a groundwater well can provide a source of water that is free of contamination and yields sufficient water throughout the year. Submersible pumps are typically powered from grid-power; however, an alternative energy source may be considered. An evaluation of the renewable energy resources has been conducted in Sacala las Lomas de San Martin Jilotepeque, Chimaltenango, Guatemala (Sacala). The drilling of a deep groundwater well has been proposed in Sacala to supply the community with sufficient, …
Time-Weighted Average Solid-Phase Microextraction (Twa-Spme) For In-Planta Detection Of Chlorinated Solvents, Emily Moore Sheehan
Time-Weighted Average Solid-Phase Microextraction (Twa-Spme) For In-Planta Detection Of Chlorinated Solvents, Emily Moore Sheehan
Masters Theses
"Recent interest in the use of phyto-mapping for plume delineation at contaminated sites has promoted a need for new and innovative sampling techniques. Solid-phase micro-extraction (SPME) methods have been developed as a chemical analysis tool offering fast, simple, non-invasive sampling without the use of solvents. In this study SPME devices were tested for applicability for in-planta detection of chlorinated solvents. To evaluate the use of SPME for VOCs in-planta a number of integrated studies were undertaken. Uptake profiles were developed for nine chlorinated solvents in a liquid polydimethylsiloxane (PDMS) matrix with 100 µm Carboxene SPME fibers. Timeweighted average (TWA) sampling …
The Assessment Of Winding Forces Due To Inrush Current In Large Transformers With Heavily Saturated Cores, Richard Howard Palmer
The Assessment Of Winding Forces Due To Inrush Current In Large Transformers With Heavily Saturated Cores, Richard Howard Palmer
Masters Theses
"It has been suspected that certain high voltage generator step-up transformers due to large inrush current occurring when the transformers were connected to the energized transmission lines but the generators were not operating. Even though the transformers are designed to withstand the winding forces developed under short circuit conditions, the transformers failed when energized. Therefore, to gain further insight into this phenomenon, this research was undertaken. The research evaluates and compares the relative magnitude of the winding forces produced under inrush and short circuit current conditions in transformers of different design and winding configurations"--Abstract, page iv.
A Mobile Water Disinfection Unit Powered By Renewable Energy Systems, Matthew Vitello
A Mobile Water Disinfection Unit Powered By Renewable Energy Systems, Matthew Vitello
Masters Theses
"The current method of disinfection of water used by the United States Army requires a significant amount of mobilization and demobilization time as well as being energy intensive. In an effort to improve small unit mobility a need for a light-weight, low maintenance, highly mobile disinfection system has arisen. In addition to the potential military use, a system of this type could provide a safe drinking water product during the aftermath of natural or man-made disasters, reducing the burden on emergency management services. A prototype system was developed that is self-powered, has low maintenance requirements, and can be stored for …
Depth Evaluation Of Damage To Aircraft Fuselage Skins Using Microwave And Millimeter Wave Methods, Andrew Dale Mcclanahan
Depth Evaluation Of Damage To Aircraft Fuselage Skins Using Microwave And Millimeter Wave Methods, Andrew Dale Mcclanahan
Masters Theses
"The depth of damage to metal surfaces is a particularly useful, sought after, and difficult to obtain piece of information, and is used to guide repair decisions. For this investigation such damage is represented as rectangular slots (cracks) or cylindrical pits. Several millimeter wave methods are presented to evaluate depth. The quarter-wavelength resonant response of cracks, excited by a probing rectangular waveguide, allows evaluation of depth using the phase of reflection coefficient. A theoretical derivation is also supplied, modeling the system as the junction of two rectangular waveguides, the probing waveguide and the crack. If the crack is filled with …
Applications Of Swarm, Evolutionary And Quantum Algorithms In System Identification And Digital Filter Design, Bipul Luitel
Applications Of Swarm, Evolutionary And Quantum Algorithms In System Identification And Digital Filter Design, Bipul Luitel
Masters Theses
"The thesis focuses on the application of computational intelligence (CI) techniques for two problems - system identification and digital filter design. In system identification, different case studies have been carried out with equal or reduced number of orders as the original system and also in identifying a blackbox model. Lowpass, Highpass, Bandpass and Bandstop FIR and Lowpass IIR filters have been designed using three algorithms using two different fitness functions. Particle Swarm Optimization (PSO), Differential Evolution based PSO (DEPSO) and PSO with Quantum Infusion (PSO-QI) algorithms have been applied in this work"--Abstract, page iii.
Hydrogen Applications For Lambert - St. Louis International Airport, Mathew Thomas
Hydrogen Applications For Lambert - St. Louis International Airport, Mathew Thomas
Masters Theses
"Today, major airports are facing challenges related to pollution, energy efficiency, and safety and security. Hydrogen and fuel cell technologies, regarded as one of the key energy solutions of the 21st century are more energy efficient and reliable than conventional systems and have the potential to diminish these challenges. These technologies can also play a significant role in reducing the noise, air, and water pollution and enhancing energy security. This paper presents the design of a set of hydrogen technologies and systems that are commercially available and are ready for practical, real-world use. The hydrogen applications selected for Lambert-St. Louis …
Functional Testing Of Faults In Asynchronous Crossbar Architecture, Sriram Venkateswaran
Functional Testing Of Faults In Asynchronous Crossbar Architecture, Sriram Venkateswaran
Masters Theses
"The challenge of extending Moore's Law past the physical limits of the present semiconductor technology calls for novel innovations. Several novel nanotechnologies are being proposed as an alternative to their CMOS counterparts, with nanowire crossbar being one of the most promising paradigms. Quite recently, a new promising clock-free architecture, called the Asynchronous Crossbar Architecture has been proposed to enhance the manufacturability and to improve the robustness of digital circuits by removing various timing related failure modes. Even though the proposed clock-free architecture offers several merits, it is not free from the high defect rates induced due to nondeterministic nanoscale assembly. …
Classification Of Fine Particles Using A Taylor-Couette Device, Navina Durgaiah Tungapindi
Classification Of Fine Particles Using A Taylor-Couette Device, Navina Durgaiah Tungapindi
Masters Theses
"The study of fine particle classification is common, especially since a well defined particle size distribution is important in most processes and products. Many methods have been developed to classify micron-size particles, and although each has its own advantage, most cannot classify particles to an extremely narrow range. This is partly due to the cohesive nature of fine particles, which can be due to electrostatic attraction, moisture, or van der Waals forces. In order to overcome this problem, a wet method of classification has been chosen here. Taylor vortices, discovered in 1923, develop in the fluid contained in the annulus …
Experiments And Modeling Of Shear-Driven Film Separation, J. L. Wegener
Experiments And Modeling Of Shear-Driven Film Separation, J. L. Wegener
Masters Theses
"Dynamic thin liquid films driven by an adjacent gas flow have been subject to many investigations due to the presence of such films in many engineering applications. More specifically though, the behavior of such films at a sharply expanding corner has received little attention, but can be observed in internal combustion engines, liquid atomizer systems, refrigerant flows in evaporators, and film drag over wetted surfaces. Efforts to validate computational models of the propagation and separation of films are limited by the lack of reliable non-intrusive techniques to measure and analyze dynamic film parameters. In this study, film propagation models and …
Automatic Vessel And Telangiectases Analysis In Dermoscopy Skin Lesion Images, Beibei Cheng
Automatic Vessel And Telangiectases Analysis In Dermoscopy Skin Lesion Images, Beibei Cheng
Masters Theses
"The blood vessels are part of the circulatory system and function to transport blood throughout the body. Vessels have their own features such as distinctive color compared to surrounding skin as well as distinctive curved and/or linear shape. Telangiectases are small dilated blood vessels near the surface of the skin or mucous membranes, measuring between 0.5 and 1 millimeter in diameter. In this research, image analysis techniques are investigated to detect vessels in dermoscopy skin lesion images. Machine vision and neural network methods are explored to discriminate skin lesions containing telangiectases from those containing normal vessels. A vessels Detection technique …
Fatigue Of Friction Stir Welded Lap Joints With Sealants, Kenneth Doering
Fatigue Of Friction Stir Welded Lap Joints With Sealants, Kenneth Doering
Masters Theses
"A lack of understanding of corrosion fatigue in friction stir welded aluminum joints prevents friction stir welding from being implemented in aerospace applications. Fatigue testing reveals a 60-75% reduction in the fatigue life of friction stir welded aluminum lap joints immersed in 3.5% NaCl solution (corrosion fatigue) compared with that of lap joints tested in ambient air. The loss in fatigue life is attributed to accelerated fatigue cracking due to hydrogen environment embrittlement. Two polymer sealant candidates are investigated: silicone rubber and nylon-11. Both sealant candidates can be applied prior to welding and seal the faying surface gaps in lap …
Design Hazard Analysis, And System Level Testing Of A University Propulsion System For Spacecraft Application, Joseph R. Siebert
Design Hazard Analysis, And System Level Testing Of A University Propulsion System For Spacecraft Application, Joseph R. Siebert
Masters Theses
"The Missouri Science and Technology Satellite (M-SAT) design team on the campus of the Missouri University of Science and Technology has developed a pair of satellites to perform an autonomous formation flight mission. To enable the mission, a unique cold gas propulsion system was developed which utilizes the refrigerant R-134a as propellant. This thesis details the design process and considerations which led to the propulsion system as integrated into the satellite for the Flight Competition Review of the NS4 competition. The design process described flowed from the mission requirements and program restrictions down through component-level requirements and resulted in a …
Communication Models For Monitoring And Mobility Verification In Mission Critical Wireless Networks, Maheswaran Thiagarajan
Communication Models For Monitoring And Mobility Verification In Mission Critical Wireless Networks, Maheswaran Thiagarajan
Masters Theses
"Recent technological advances have seen wireless sensor networks emerge as an interesting research topic because of its ability to realize mission critical applications like in military or wildfire detection. The first part of the thesis focuses on the development of a novel communication scheme referred here as a distributed wireless critical information-aware maintenance network (DWCIMN), which is presented for preventive maintenance of network-centric dynamic systems. The proposed communication scheme addresses quality of service (QoS) issues by using a combination of a head-of-the-line queuing scheme, efficient bandwidth allocation, weight-based backoff mechanism, and a distributed power control scheme. A thorough analysis of …
Decision-Based Design Under Uncertainty With Intervals, Sashank Vasireddy
Decision-Based Design Under Uncertainty With Intervals, Sashank Vasireddy
Masters Theses
"Design requires a series of decisions, and one of the major challenges engineering designers face is making decisions under uncertainty. The engineering designer must choose the best design among various alternatives. This work evaluates the use of utility functions to make decisions under uncertainty with both random and interval variables. Uncertainty cannot be eliminated completely, but it can be reduced. Most current methods treat only aleatory uncertainty. Here, however, both aleatory and epistemic uncertainties are addressed in the context of engineering design. Methods such as moment matching method and worst case analysis are used to incorporate uncertainty into design problems"--Abstract, …
The Corrosion Of Ni₃Si Alloys In Sulfuric Acid, Christopher Marc Larson
The Corrosion Of Ni₃Si Alloys In Sulfuric Acid, Christopher Marc Larson
Masters Theses
"Hydrogen production from water, the world's most renewable natural resource, can provide an economical and sustainable form of energy for the future. One means to achieve this is with a nuclear reactor-based sulfur-iodine (S-I) thermochemical cycle. Currently there are few materials available, other than precious metals like gold and platinum, that possess the corrosion resistance and mechanical properties required for the sulfuric acid decomposition loop of the S-I process. However, alloys based on Ni₃Si show promise to be a more affordable, corrosion resistant materials option for this technology. In this study, the corrosion behavior of NiSi₂₂ and NiSi₂₀(Nb,Ti)₃ alloys in …
Continuous Control Of Lunar Orbits Via Electric Propulsion, Sunil Aggarwal
Continuous Control Of Lunar Orbits Via Electric Propulsion, Sunil Aggarwal
Masters Theses
"To find definite answers for the presence of water on the poles of Moon, to facilitate selection of future lunar landing sites and aid in construction of architectural bases, to assist proper lunar resource utilization and to improve lunar gravity models there is a great interest and need for highly accurate, reliable and efficient lunar surface mapping and communication. This thesis is intended to aid in proper selection of orbits for future lunar missions by demonstrating the impact of using electric propulsion on the search space of feasible and useful lunar orbits. The requirements for future lunar mapping and communication …
Verifying Module Heuristics For Large Scale Products, Rachel Marie Day
Verifying Module Heuristics For Large Scale Products, Rachel Marie Day
Masters Theses
"Decreasing time and costs is a major objective in many businesses today. Including modularity in the early design phases can effectively decrease time spent on and costs associated with a project. The task of identifying modules within a product early in the design process (when decisions are less expensive) is made less daunting by using the techniques of functional modeling and module heuristics. The two papers that form this thesis discuss the results of the efforts to verify the module heuristics on large products. Observations on needed modifications to the functional modeling technique and original module heuristics are reported along …
Modeling And Simulation Of Electrochemical Magneto Hydro Dynamics, Debamoy Sen
Modeling And Simulation Of Electrochemical Magneto Hydro Dynamics, Debamoy Sen
Masters Theses
"This thesis focuses on how the electrochemical magneto hydro dynamic problem is solved through numerical simulation for a two dimensional millielectrode electrochemical cell and a three dimensional microelectrode array cell. Electrochemical processes are enhanced by magnetic fields through the introduction of body forces such as Lorentz force. Through modeling and numerical simulations, experimental results can be integrated with theory. Such simulations will aid in the prediction of mass transfer limited currents and visualization of flow profiles in an electrochemical cell. The numerical solution of the equation system is made possible by the finite volume method used in the FLUENT Computational …
Development Of A One Dimensional Subsurface Contaminant Transport Model With Stochastic Applications, Benjamin Waldon Johnson
Development Of A One Dimensional Subsurface Contaminant Transport Model With Stochastic Applications, Benjamin Waldon Johnson
Masters Theses
"Contaminant source release history is a necessary element of contaminant mass transport simulation in the saturated zone. The source release history is unknown at many sites, and many inverse models have been developed to define finite release histories. To define a likely domain of three source history parameters, a mass balancebased one dimensional approach is developed and tested by discretizing the spatial domain into bands. By incorporating the approach in a spreadsheet model, observed data is represented by both variable length and constant length bands of analysis. Each representation of observed data was tested to determine the most appropriate band …
On-Line Depth Measurement Of Micro-Scale Laser Drilled Holes, Rock Allen Powell
On-Line Depth Measurement Of Micro-Scale Laser Drilled Holes, Rock Allen Powell
Masters Theses
"A micron-precision micro-hole depth detection scheme has been developed which utilizes a confocal structure and a photomultiplier tube as a photodetector. This scheme is experimentally confirmed to posses an accuracy of greater than 95% for micro-holes on the order of one-hundred microns in diameter and tens of microns in depth and could be easily be integrated for the control of industrial and research oriented laser micro-machining process"--Abstract, page iii.
On The Effects Of Small-Scale Fading And Mobility In Mobile Wireless Communication Network, Bandana Paudel
On The Effects Of Small-Scale Fading And Mobility In Mobile Wireless Communication Network, Bandana Paudel
Masters Theses
"In this study, a comprehensive analysis of the impact of mobility on end-to-end performance measures of Mobile Ad Hoc Network is performed by using small-scale fading models. Network simulation is performed in order to study a wide range of phenomena occurring during MANET communication. The effectiveness of three reactive routing protocols against different level of mobility is observed under varying network parameter like the network size, number of nodes and network connectivity. The study reveals that the network sparseness or density favors one or the other routing mechanism under varying mobility. Outcome of the simulation also provides a great deal …
Localization Of Nodes In Wired And Wireless Networks, Hindu Kothapalli
Localization Of Nodes In Wired And Wireless Networks, Hindu Kothapalli
Masters Theses
"This thesis focuses on the implementation of algorithms for localization of nodes in wired and wireless networks. The thesis is organized into two papers. The first paper presents the localization algorithms based on time of arrival (TOA) and time difference of arrival (TDOA) techniques for computer networks such as the Internet by using round-trip-time (RTT) measurements obtained from known positions of the gateway nodes. The RTT values provide an approximate measure of distance between the gateway nodes and an unknown node. The least squares technique is then used to obtain an estimated position of the unknown node. The second paper …
Development And Evaluation Of An Effective Process For The Recovery Of Oil And Detoxification Of Meal From Jatropha Curcas, Sarthak Gaur
Development And Evaluation Of An Effective Process For The Recovery Of Oil And Detoxification Of Meal From Jatropha Curcas, Sarthak Gaur
Masters Theses
"There has been significant research on biofuels to ensure national security and economic stability of the US. Jatropha curcas, a hardy plant, holds tremendous potential as a biodiesel source and cattle feed-stock largely due to its high triglyceride and crude protein content. However, its viable economic utilization is limited due to the presence of important toxic compounds, phorbol esters. A novel and efficient process has been developed that obtains high yields of jatropha oil and detoxifies the defatted (oil free) jatropha meal. Principles of solid-liquid extraction were utilized to detoxify the meal and then liquid chromatography was employed to analyze …
Modeling Of Vias And Via Arrays In High Speed Printed Circuit Boards, Arun Reddy Chada
Modeling Of Vias And Via Arrays In High Speed Printed Circuit Boards, Arun Reddy Chada
Masters Theses
"This thesis presents modeling approaches for fast calculation of signals in dense via arrays in high speed printed circuit boards (PCBs) and model to hardware correlation study of solid and perforated disk resonators. A 2D finite difference (FD) method to extract the via capacitance which includes the via pad capacitance obtained by solving the laplace equation in the via domain in multi-layer geometries is presented and validated with analytical formulation for via capacitance. Next, closed-form expression for the impedance of an infinitely large parallel plane pair is derived and validated by comparing with cavity model for several numerical examples. The …
Preventing Chemical Product Failure, Kenneth Ombete
Preventing Chemical Product Failure, Kenneth Ombete
Masters Theses
"The purpose of this thesis is to demonstrate a research methodology to prevent chemical product failures. This methodology extends the risk in early design (RED) method for prevention of failure in electromechanical products to include products with chemical subsystems. Inclusion of this domain is demanded by the ever-growing semiconductor and energy industries. The RED method was extended by first identifying principal chemical failure modes and adding them to the failure mode taxonomy. The RED database was then augmented with historical failures of products that included chemical subsystems. Finally, the extension was validated with a case study of a fuel cell"--Abstract, …
Stressed-Eye Analysis And Jitter Separation For High-Speed Serial Links, Nitin Radhakrishnan
Stressed-Eye Analysis And Jitter Separation For High-Speed Serial Links, Nitin Radhakrishnan
Masters Theses
"As the computer and electronics industry moves towards higher data rates, the most important concern in the field of signal integrity is jitter. A data communication link path often consists of a transmitter, a channel, and a receiver. Many mechanisms can contribute to jitter, a timing uncertainty in the received signal. For example, transmitters have intrinsic noise sources that contribute to random jitter and to certain types of deterministic jitter. In addition, external coupling may cause periodic jitter. The bandwidth limitation of the channel also contributes to a fourth type of jitter, inter-symbol interference. This thesis studies the various components …
Control Aspects Of A Double-Input Buckboost Power Electronic Converter, Deepak Somayajula
Control Aspects Of A Double-Input Buckboost Power Electronic Converter, Deepak Somayajula
Masters Theses
"Systems in which two or more energy sources combine to supply power to a common load are called hybrid energy systems. Applications of these systems have grown due to their flexibility and reliability. Hybrid energy systems have been successfully implemented in hybrid electric vehicles and wind-solar systems where two or more energy sources share the same load. Double-input (DI) dc-dc power electronic converters (DIPECs) have been gaining popularity in hybrid energy systems due to their reduced component count and control simplicity. In addition, employing DIPECs increases the reliability, stability, and flexibility of the system. In this thesis, a small-signal model …
Numerical Modeling And Analysis Of Complex Electromagnetic Structures, Including Those Containing Ferrites, Andrea Orlando
Numerical Modeling And Analysis Of Complex Electromagnetic Structures, Including Those Containing Ferrites, Andrea Orlando
Masters Theses
"Application of fast switching amplifiers in power converters, and especially in power inverters, causes unwanted radiated emission, which is a consequence of common mode (CM) currents arising in feed wire bundles. Ferrite chokes are commonly used to suppress those CM currents by increasing the CM impedance of circuits without affecting the differential mode currents, which is important for undisturbed operation of the converters or inverters. Their effective impedance is the main design concern, and it is determined by the material intrinsic properties (permeability, permittivity) and geometry. The goal of this work is to analytically correlate the geometrical and material properties …
Reliability-Based Design With System Reliability And Design Improvement, Gagandeep Singh Saini
Reliability-Based Design With System Reliability And Design Improvement, Gagandeep Singh Saini
Masters Theses
"This thesis focuses on developing a methodology for accurately estimating series system probability of failure. Existing methods for series system based design optimization are not that accurate because they assign reliability to each failure mode; as a result complete system reliability goes down. According to method proposed in this work, the user will assign required system reliability at the start and then optimizer will apportion reliability to every failure mode in order to meet required system reliability level. Detlevson second order upper bounds are used to estimate system probability of failure. Several examples have been shown to verify the results …