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Full-Text Articles in Engineering

Design And Analysis Of A Compliant Mechanism Spinal Implant, Eric M. Stratton May 2010

Design And Analysis Of A Compliant Mechanism Spinal Implant, Eric M. Stratton

Theses and Dissertations

This thesis introduces and presents the modeling of a novel compliant spinal implant designed to reduce back pain and restore function to degenerate spinal disc tissues as well as provide a mechanical environment conducive to healing the tissues. The initial objectives for this device development and the focus of this work are modeling and validation of the force-deflection relationships and stress analysis. Modeling was done using the pseudo-rigid-body model to create a 3 degree of freedom mechanism for flexion-extension (forward-backward bending) and a 5 degree of freedom mechanism for lateral bending (side-to-side). These models were analyzed using the principle of …


Multiobjective Optimization Method For Identifying Modular Product Platforms And Modules That Account For Changing Needs Over Time, Patrick K. Lewis Apr 2010

Multiobjective Optimization Method For Identifying Modular Product Platforms And Modules That Account For Changing Needs Over Time, Patrick K. Lewis

Theses and Dissertations

Natural and predictable changes in consumer needs often require the development of new products. Providing solutions that anticipate, account for, and allow for these changes over time is a significant challenge to manufacturers and design engineers. Products that adapt to these changes through the addition of modules reduce production costs through product commonality and provide a set of products that cater to customization and adaptation. In this thesis, a multiobjective optimization design method using s-Pareto frontiers – sets of non-dominated designs from disparate design models - is developed and used to identify a set of optimal adaptive product designs that …


Design And Feasibility Testing For A Ground-Based, Three-Dimensional, Ultra-High-Resolution, Synthetic Aperture Radar To Image Snowpacks, Stephen Joseph Preston Apr 2010

Design And Feasibility Testing For A Ground-Based, Three-Dimensional, Ultra-High-Resolution, Synthetic Aperture Radar To Image Snowpacks, Stephen Joseph Preston

Theses and Dissertations

This thesis works through the design of a radar-based system for imaging snowpacks remotely and over large areas to assist in avalanche prediction. The key to such a system is the ability to image volumes of snow at shallow, spatially-varying angles of incidence. To achieve this prerequisite, the design calls for a ground-based Synthetic Aperture Radar (SAR) capable of generating three-dimensional, ultra-high-resolution images of a snowpack. To arrive at design parameters for this SAR, the thesis works through relevant principles in avalanche mechanics, alpine-snowpack geophysics, and electromagnetic scattering theory. The thesis also works through principles of radar, SAR, antenna, and …


Using Buckling-Restrained Braces In Eccentric Configurations, Gary S. Prinz Apr 2010

Using Buckling-Restrained Braces In Eccentric Configurations, Gary S. Prinz

Theses and Dissertations

Ductile braced frames are often used to resist lateral earthquake loads in steel buildings; however the presence of a brace element can sometimes interfere with architectural features. One common type of ductile braced frame system sometimes used to accommodate architectural features is the eccentrically braced frame (EBF). In order to dissipate seismic forces, EBF beam regions (called links) must sustain large inelastic deformations. EBF links with column connections must transmit large moments and shear forces to facilitate link rotation. Experiments have shown that welded link-to-column connections tend to fracture in the link flange prior to large link rotations. This study …


Summary Of Feedback Edge Set Papers, Jonathan Johnson Apr 2010

Summary Of Feedback Edge Set Papers, Jonathan Johnson

Faculty Publications

The problem of finding a set of edges F from a directed graph G = (V,E) such that the graph G0 = (V,E − F) contains no cycles is known as the feedback edge set (FES) problem or the feedback arc set problem. A related problem is the minimum feedback edge set problem, in which the feedback edge set F must be minimal. The feedback edge set problem has application in applying a common reliability technique called triple modular redundancy to FPGA circuit designs where configuration memory scrubbing is employed [1].


A Design Framework That Employs A Classification Scheme And Library For Compliant Mechanism Design, Brian Mark Olsen Apr 2010

A Design Framework That Employs A Classification Scheme And Library For Compliant Mechanism Design, Brian Mark Olsen

Theses and Dissertations

Limited resources are currently available to assist engineers in implementing compliant members into mechanical designs. As a result, engineers often have little to no direction incorporating compliant mechanisms. This thesis develops a conceptual design framework and process that utilizes a proposed classification scheme and a library of mechanisms to help engineers incorporate compliant mechanisms into their applications. As the knowledge related to the synthesis and analysis of compliant mechanisms continues to grow and mature, and through the classification scheme established in this thesis, compliant mechanisms may become more extensively used in commercial mechanical designs. This thesis also demonstrates a design …


Development Of Criteria For Lamina Emergent Mechanism Flexures With Specific Application To Metals, Devin Bradley Ferrell Apr 2010

Development Of Criteria For Lamina Emergent Mechanism Flexures With Specific Application To Metals, Devin Bradley Ferrell

Theses and Dissertations

This thesis introduces new revolute and torsional lamina emergent mechanism (LEM) flexure designs that are suited for use in metals. Previous LEM flexures have been designed for use in highly elastic materials, such as polymers. In extending LEM flexure designs to metals, a LEM flexure design criteria is also introduced. The LEM flexure criteria is based on relative performance between the LEM flexure and a performance datum which the LEM flexure must improve upon. This performance datum, or benchmark, is a section of lamina that is of the same overall length, width, and thickness as the LEM flexure. An analysis …


Field Evaluation Of Asphalt Overlays On State Route 30 In Northern Utah, Mark J. Butler Apr 2010

Field Evaluation Of Asphalt Overlays On State Route 30 In Northern Utah, Mark J. Butler

Theses and Dissertations

The purpose of this research was to compare the rutting, cracking, and development of roughness of two asphalt overlay types commonly used in northern Utah and to evaluate how well the Mechanistic-Empirical Pavement Design Guide (MEPDG) can predict the observed results. AC-10 and PG 64-34 asphalt overlay materials were paved in a checkerboard pattern at a test site on State Route 30 near Logan, Utah, and observed for 3 years at 6-month intervals. Primary data included rutting, cracking, and roughness. At the conclusion of the 3-year evaluation period, rut depths were 0.08 in. deeper, on average, in the AC-10 overlay …


Secret Key Establishment Using Wireless Channels As Common Randomness In Time-Variant Mimo Systems, Chan Chen Apr 2010

Secret Key Establishment Using Wireless Channels As Common Randomness In Time-Variant Mimo Systems, Chan Chen

Theses and Dissertations

Encryption of confidential data with a secret key has become a widespread technique for securing wireless transmissions. However, existing key distribution methods that either deliver the secret key with a key distribution center or exchange the secret key using public-key cryptosystems are unable to establish perfect secret keys necessary for symmetric encryption techniques. This research considers secret key establishment, under the broad research area of information theoretic security, using the reciprocal wireless channel as common randomness for the extraction of perfect secret keys in multiple-input multiple-output (MIMO)communication systems. The presentation discusses the fundamental characteristics of the time-variant MIMO wireless channel …


Signal Processing Methods For Ultra-High Resolution Scatterometry, Brent A. Williams Apr 2010

Signal Processing Methods For Ultra-High Resolution Scatterometry, Brent A. Williams

Theses and Dissertations

This dissertation approaches high resolution scatterometry from a new perspective. Three related general topics are addressed: high resolution σ^0 imaging, wind estimation from high resolution σ^0 images over the ocean, and high resolution wind estimation directly from the scatterometer measurements. Theories of each topic are developed, and previous approaches are generalized and formalized. Improved processing algorithms for these theories are developed, implemented for particular scatterometers, and analyzed. Specific results and contributions are noted below. The σ^0 imaging problem is approached as the inversion of a noisy aperture-filtered sampling operation-extending the current theory to deal explicitly with noise. A maximum aposteriori …


Preliminary Results Of Combining Low Frequency Low Intensity Ultrasound And Liposomal Drug Delivery To Treat Tumors In Rats, William G. Pitt, Ghaleb A. Husseini, Beverly L. Roeder, David Dickinson, David Warden, Jonathan Hartley, Peter Jones Mar 2010

Preliminary Results Of Combining Low Frequency Low Intensity Ultrasound And Liposomal Drug Delivery To Treat Tumors In Rats, William G. Pitt, Ghaleb A. Husseini, Beverly L. Roeder, David Dickinson, David Warden, Jonathan Hartley, Peter Jones

Faculty Publications

Ultrasound is a convenient trigger for site-specific drug delivery in cancer therapy. Nanosized liposomes formulated from soy phosphatidyl choline, cholesterol, 1,2-distearoyl-sn-glycero3-phosphoethanolamine-N-[carboxy(polyethylene glycol)-2000] and alpha-tocopherol were loaded with Doxorubicin (Dox)using a pH gradient. The liposomal suspension was infused through the tail vein of BDIX rats possessing bilateral intradermal DHD/K12 tumors on their hind legs. Then 20-kHz ultrasound was applied to only one of the tumors for 15 minutes. This therapy was repeated weekly for 4 weeks. The results showed that in five of sixrats, the tumors regressed to non-measurable size within 4 weeks. A paired comparison of the normalized size of …


Syngas Fermentation: Quantification Of Assay Techniques, Reaction Kinetics, And Pressure Dependencies Of The Clostridial P11 Hydrogenase, Bradley E. Skidmore Mar 2010

Syngas Fermentation: Quantification Of Assay Techniques, Reaction Kinetics, And Pressure Dependencies Of The Clostridial P11 Hydrogenase, Bradley E. Skidmore

Theses and Dissertations

Ethanol usage as a transportation fuel is rapidly increasing in the United States. Production of ethanol from cellulose feedstocks via gasification followed by syngas fermentation offers an environmentally friendly approach that mitigates many of the adverse effects associated with production from corn. In the syngas fermentation process, the hydrogenase enzyme of the fermentation bacterium, Clostridium P11 for this work, supplies electrons to the metabolic pathway, facilitating ethanol production. In this thesis, an assay for P11 hydrogenase activity was developed. It was determined that 1) less than 4 minutes of sparging with 50 sccm H2 is needed to reduce O2 levels …


Processing A Nickel Nanostrand And Nickel Coated Carbon Fiber Filled Conductive Polyethylene By Injection Molding, David Anthony Whitworth Mar 2010

Processing A Nickel Nanostrand And Nickel Coated Carbon Fiber Filled Conductive Polyethylene By Injection Molding, David Anthony Whitworth

Theses and Dissertations

A new method for pre-impregnating nickel coated carbon fiber with a thermoplastic polymer to make towpreg, similar to a recently developed coating-line by João P. Nunes et al and a new electrically conductive thermoplastic are developed. A melted bath was used to help mitigate health concerns and waste for dispersion of nickel coated carbon fibers (NCF) in low density polyethylene (LDPE). This towpreg was then mixed with more LDPE or a mixture of LDPE and nickel nanostrands (NiNS) to a desired filler volume fraction to test the electrical conductivity of the composite. Some of these mixtures were then injection molded …


Optimal Design Of A Planar 3-Rpr Haptic Interface Based On Manipulability, Wesley Kay Harris Mar 2010

Optimal Design Of A Planar 3-Rpr Haptic Interface Based On Manipulability, Wesley Kay Harris

Theses and Dissertations

A haptic interface is a robotic force feedback device that provides a sense of touch to users of virtual reality simulations. This thesis presents a general method for the design optimization of parallel planar haptic devices based on maximizing the manipulability of the interface over its workspace. Manipulability is selected as the key design objective to ensure avoidance of singular configurations within the workspace and to maximize the interface's ability to generate feedback forces and torques in each direction in each handle location and orientation. The optimization approach developed in this thesis results in a set of candidate designs that …


Evaluation Of The Accuracy Of The Incremental Queue Accumulation Delay Estimation Method, Yaye Mallon Keita Mar 2010

Evaluation Of The Accuracy Of The Incremental Queue Accumulation Delay Estimation Method, Yaye Mallon Keita

Theses and Dissertations

Knowing the performance of intersections is of utmost importance to engineers today. It affects the development, advancement, and future economic growth status of the city or place in which the intersections are located. The performance level is inferred from the levels of service of the intersections and one common way to measure the levels of service is to estimate delays for those intersections. Therefore, the estimation of delays at intersections is a very recurrent study done by traffic engineers. Different methods of calculating delays exist. Those methods are not ideal for estimating delay for all cases. The call for better …


Development Of A Plasma Arc Manufacturing Process And Machine To Create Metal Oxide Particles In Water From Wire Feedstock, Jonathan Alan George Mar 2010

Development Of A Plasma Arc Manufacturing Process And Machine To Create Metal Oxide Particles In Water From Wire Feedstock, Jonathan Alan George

Theses and Dissertations

A plasma arc erosion process can be used to create metal and metal oxide particles in the ultra-fine size range (<70 µm). An electric arc is struck between two metallic electrodes, submerged in water, melting the surface of the electrodes. When the arc collapses a high energy pressure wave strikes the molten surface of the electrode. When the pressure wave strikes the molten metal, small metallic particles are created from the molten metal and are immediately cooled in the water. Previous research developed a process that used a constant current power supply and electrode motion to create ultra-fine particles. This research improves upon previous research by using a pulsed power supply similar to those used in Electrical Discharge Machining (EDM). The pulsed power supply eliminates the need for electrode motion and improves the rate of particle production, provides control over size of the particles created, and reduces the amount of energy needed to produce the particles. The new process improves the maximum particle production rate from 3.6 g/hr to 14 g/hr, provides a method to control the mean diameter of the particles produced, and reduces the amount of energy needed from 200 kWh/kg(previous constant current process) to 10.6 kWh/kg(using the pulsed power supply).


Investigation Of Rf Curing Parameters In Resin Infusion Molding, Christopher K. Love Mar 2010

Investigation Of Rf Curing Parameters In Resin Infusion Molding, Christopher K. Love

Theses and Dissertations

The purpose of this study is to investigate RF or Radio Frequency energy as a viable alternative to traditional heating methods for the purpose of curing resins used in resin infusion molding, a molding system for polymeric composites. Traditional heating/curing methods include technologies such as room temperature, oven, microwave, infrared, and ultraviolet. Although RF curing provides far more advantages than disadvantages, its implementation into a manufacturing process can be challenging. Specifically, three critical elements must be present in order for RF to function in a manner that is profitable to the manufacturer. Those elements are: (1) the proper generator (voltage …


An Enhanced Data Model And Tools For Analysis And Visualization Of Levee Simulations, Thomas Richard Griffiths Mar 2010

An Enhanced Data Model And Tools For Analysis And Visualization Of Levee Simulations, Thomas Richard Griffiths

Theses and Dissertations

The devastating levee failures associated with hurricanes Katrina and Rita, and the more recent Midwest flooding, placed a spotlight on the importance of levees and our dependence on them to protect life and property. In response to levee failures associated with the hurricanes, Congress passed the Water Resources Development Act of 2007 which established a National Committee on Levee Safety. The committee was charged with developing recommendations for a National Levee Safety Program. The Secretary of the Army was charged with the establishment and maintenance of a National Levee Database. The National Levee Database is a critical tool in assessing …


Aerial Recovery Of Micro Air Vehicles: Orbit Estimation And Tracking, Daniel Clarke Carlson Mar 2010

Aerial Recovery Of Micro Air Vehicles: Orbit Estimation And Tracking, Daniel Clarke Carlson

Theses and Dissertations

Aerial recovery of autonomous micro air vehicles (MAVs) presents many unique challenges due to the difference in size and speed of the recovery vehicle and MAV. This thesis presents algorithms to enable an autonomous MAV to estimate the orbit of a recovery vehicle and track the orbit until the final docking phase. Methods for estimating ellipses that are rotated out of the x − y plane are developed and demonstrated through simulation. These algorithms are shown to be robust to noise and stable numerically. Parameter update methods that are computationally inexpensive, such as recursive least squares and Kalman filtering, are …


Recognizing Parametric Geometry From Topology Optimization Results, Shane H. Larsen Mar 2010

Recognizing Parametric Geometry From Topology Optimization Results, Shane H. Larsen

Theses and Dissertations

Topology Optimization has been proven to be a useful tool in discovering non-intuitive optimal designs subject to certain design constraints. The results of Topology Optimization are either represented as a tessellation object composed of thousands of triangular surfaces, or as a point cloud. In either case, the results of Topology Optimization are not suited for use in subsequent steps of the design process which require 3D parametric CAD (Computer Aided Design) models. Converting Topology Optimization results into parametric CAD geometry by hand is an extremely tedious and time consuming process which is highly subjective. This thesis presents a shape recognition …


Automatic Identification And Tracking Of Retraction Fibers In Time-Lapse Microscopy, Meher Talat Shaikh Mar 2010

Automatic Identification And Tracking Of Retraction Fibers In Time-Lapse Microscopy, Meher Talat Shaikh

Theses and Dissertations

Digital image processing is widely used in the field of time-lapse microscopy and biological research to provide statistical data of cellular dynamics. The data can provide more comprehensive understanding of the molecular phenomenon. Further, digital image processing enables rapid and consistent quantification of qualitative observations. The image processing model examined here provides a study to identify structures called retraction fibers (RFs) that are formed during epithelial-mesenchymal transition (EMT) [1], an important developmental process which also occurs during cancer metastasis. Quantifying RF formation is an important task for biologists studying cellular regulation of EMT. This thesis work uses digital image processing …


Generalized Image Formation For Pulsed And Lfm-Cw Synthetic Aperture Radar, Evan C. Zaugg Mar 2010

Generalized Image Formation For Pulsed And Lfm-Cw Synthetic Aperture Radar, Evan C. Zaugg

Theses and Dissertations

Approximations made in the traditional signal model for synthetic aperture radar (SAR) processing cause defocusing of the radar images when the system operates under conditions where the approximations lose validity. This dissertation investigates a number of these approximations and presents algorithmic improvements based on generalizations of the approxmations of the SAR signal model. These improvements result in better focused imagery from SAR systems with varied designs and parameters. Among the advancements presented is the development of a generalized chirp-scaling algorithm and a generalized frequency scaling algorithm to address the problems caused by approximations based on a Taylor series expansion of …


Design Method For Optimized Wideband Iterative Differential Amplifier In Mos Technology, Steven L. Minch Mar 2010

Design Method For Optimized Wideband Iterative Differential Amplifier In Mos Technology, Steven L. Minch

Theses and Dissertations

Wideband amplifiers are an important part of analog design, and much effort has been expended in improving them. A popular implementation of a wideband amplifier is to use one or two stages with high gain in one or both stages. An alternative to this method is presented in this work, developed for Metal Oxide Semiconductor (MOS) amplifiers. The new approach, building on previous work in bipolar technology, uses multiple differential MOS stages to achieve similar gain requirements to other wideband amplifiers. It is shown that multiple stages with low gain, if implemented according to the present design method, can lead …


Synchronization Voter Insertion Algorithms For Fpga Designs Using Triple Modular Redundancy, Jonathan Mark Johnson Mar 2010

Synchronization Voter Insertion Algorithms For Fpga Designs Using Triple Modular Redundancy, Jonathan Mark Johnson

Theses and Dissertations

Triple Modular Redundancy (TMR) is a common reliability technique for mitigating single event upsets (SEUs) in FPGA designs operating in radiation environments. For FPGA systems that employ configuration scrubbing, majority voters are needed in all feedback paths to ensure proper synchronization between the TMR replicates. Synchronization voters, however, consume additional resources and impact system timing. This work introduces and contrasts seven algorithms for inserting synchronization voters while automatically performing TMR. The area cost and timing impact of each algorithm on a number of circuit benchmarks is reported. The work demonstrates that one of the algorithms provides the best overall timing …


Particle Image Velocimetry Analysis On The Effects Of Stator Loading On Transonic Blade-Row Interactions, Scott B. Reynolds Mar 2010

Particle Image Velocimetry Analysis On The Effects Of Stator Loading On Transonic Blade-Row Interactions, Scott B. Reynolds

Theses and Dissertations

Experiments have been performed using the Air Force Research Laboratory (AFRL) Blade-Row Interaction (BRI) rig to investigate interactions between a loaded stator and transonic rotor. The BRI rig is a high-speed, highly loaded compressor consisting of a swirler/deswirler, a transonic rotor and a stator. The swirler/deswirler of the BRI rig is used to simulate an embedded transonic fan stage with realistic geometry which produces a wake through diffusion. Details of the unsteady flow field between the stator and rotor were obtained using Particle Image Velocimetry (PIV). Flow visualization images and PIV data that facilitate analysis of vortex shedding, wake motion, …


Methods To Streamline Laminate Composite Design, Analysis, And Optimization, Ammon Ikaika No Kapono Hepworth Mar 2010

Methods To Streamline Laminate Composite Design, Analysis, And Optimization, Ammon Ikaika No Kapono Hepworth

Theses and Dissertations

Advanced composite materials have seen major market growth in recent years due to their high strength and low weight properties. These materials are often made using a process that creates a composite laminate by stacking several composite layers together. However, the design, analysis and optimization of laminate composite materials are often a labor intensive process when done manually. This thesis discusses CAD independent algorithms that are integrated into commercial CAD tools to streamline these processes. Methods have been developed to automatically create 3D ply geometry for a laminate composite lay-up, streamline the creation of a laminate composite finite element model …


Integrating Engineering And Communication Tools For The Automation Of Design Rationale Capture, Kenneth John Mix Mar 2010

Integrating Engineering And Communication Tools For The Automation Of Design Rationale Capture, Kenneth John Mix

Theses and Dissertations

Product development is continually becoming more challenging as global competition requires more efficient design methods. The reuse of company knowledge, specifically the design rationale that occurs during projects is essential to success. This thesis presents a method for integrating engineering and communication tools for purposes of automating the capture of communication-based design rationale. The method is based on four basic principles: to integrate, to make data retrievable, to minimize user interaction, and to store as much DR as possible. The core method consists of two primary operations, the first being to capture the design rationale, and the second being to …


Multi-Aperture Coherent Change Detection And Interferometry For Synthetic Aperture Radar, David D. Madsen Mar 2010

Multi-Aperture Coherent Change Detection And Interferometry For Synthetic Aperture Radar, David D. Madsen

Theses and Dissertations

Interferometry and coherent change detection (CCD) utilize phase differences between complex SAR images to find terrain height and to detect small changes between images, respectively. A new method for improving interferometry and CCD using multiple sub-apertures is proposed. Using backprojection processing, multiple sub-aperture images are created for a pair of flights. An interferogram and coherence map is made from each sub-aperture. For CCD, each sub-aperture coherence map offers an independent estimate of the coherence over the same area. By combining coherence maps, low coherence areas associated with residual motion errors are reduced, shadowed areas are minimized, and the overall coherence …


Design And Evaluation Of A Humanoid Robot For Autism Therapy, Daniel J. Ricks Mar 2010

Design And Evaluation Of A Humanoid Robot For Autism Therapy, Daniel J. Ricks

Theses and Dissertations

Recent evidence has shown that children with autism may behave more pro-socially when interacting with a robot than with a human. The objective of this research is to develop a robotic system for use in the clinical treatment of children with autism. The governing assumption behind this thesis is that using a robot in a clinic, under the guidance of a trained therapist, may lead to therapeutic benefits that may not be achieved without the presence of the robot. The robot Troy was developed to fulfill such a role in a clinical setting. The primary objective was to design a …


Bidirectional Electrowetting Actuation With Voltage Polarity Dependence, Nathan B. Crane, Alex A. Volinsky, Pradeep Mishra, Ajay Rajgadkar, Mehdi Khodayari Mar 2010

Bidirectional Electrowetting Actuation With Voltage Polarity Dependence, Nathan B. Crane, Alex A. Volinsky, Pradeep Mishra, Ajay Rajgadkar, Mehdi Khodayari

Faculty Publications

This work presents an electrowetting system in which the actuation direction depends on the polarity of the applied voltage. Since electrowetting response depends on the voltage squared, it is typically independent of voltage sign to first order. However, the introduction of an electrochemicaal diode into the equivalent electrical circuit permits polarity-dependent behavior. Electrochemical diodes were created by making holes in the dielectric. The aluminum electrodes passivate and prevent current flow in one direction, creating diode-like behavior with high breakdown voltage. The resulting actuation forces were directly measured and are of comparable magnitude for both actuation directions.