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Articles 6031 - 6060 of 11510

Full-Text Articles in Engineering

Numerical Modeling Of Free Surface Flows Using Depth Averaged And 3d Models, Khaled Mamdouh Mohamed Abdo Dec 2014

Numerical Modeling Of Free Surface Flows Using Depth Averaged And 3d Models, Khaled Mamdouh Mohamed Abdo

Theses and Dissertations

The objectives of the research presented in this dissertation are to develop and apply numerical models to study free surface flows under different boundary conditions, bedform geometry and channel configuration. A 2D depth-averaged model is developed by solving the Saint Venant or the shallow water equations using a finite volume method. An existing 3D model, developed in-house, that solves the Reynoldsaveraged Navier-Stokes equations and conservation equations for suspended sediment and conservative species is adapted for free surface flows by solving the volume of fluid (VOF) equation using a compressive interface capturing scheme for arbitrary meshes, CICSAM. The depth-averaged or shallow …

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An Engineering Approach For The Design Of Archaeological Reburial Systems, Angel Ari Perez Mejia Dec 2014

An Engineering Approach For The Design Of Archaeological Reburial Systems, Angel Ari Perez Mejia

Theses and Dissertations

Archaeological sites are a non-renewable resource which is often our only link to the past. However, sites are under constant threat of destruction due to construction activities. Civil engineers and archaeologists must the work together to ensure both the continued survival of archaeological sites while allowing for development to continue. Reburial systems, when properly designed and constructed, allow for the protection of archaeological sites while allowing the continued use of the land. However, because reburial as an intentional conservation technique is relatively modern, practice is fragmented and there are no universally accepted guidelines. Current reburial system design relies on prescriptive …

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Piezotransistive Iii-V Nitride Microcantilever Based Mems/Nems Sensor For Photoacoustic Spectroscopy Of Chemicals, Abdul Hafiz Ibne Talukdar Dec 2014

Piezotransistive Iii-V Nitride Microcantilever Based Mems/Nems Sensor For Photoacoustic Spectroscopy Of Chemicals, Abdul Hafiz Ibne Talukdar

Theses and Dissertations

Microcantilevers are highly attractive as transducers for detecting chemicals, explosives, and biological molecules due to their high sensitivity, micro-scale dimensions, and low power consumption. Though optical transduction of the mechanical movement of the microcantilevers into an electrical signal is widely practiced, there is a continuous thrust to develop alternative transduction methods that are more conducive to the development of compact miniaturized sensors. Piezoelectric and piezoresistive transduction methods are two of the most popular ones that have been utilized to develop miniaturized sensor systems. Piezoelectric cantilevers, which are commonly made of PZT film, have demonstrated very high sensitivity; however, they suffer …

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A Three-Dimensional-Engineered Matrix To Study The Microenvironment Of Cancer Stem Cells, Samaneh Kamali Sarvestani Dec 2014

A Three-Dimensional-Engineered Matrix To Study The Microenvironment Of Cancer Stem Cells, Samaneh Kamali Sarvestani

Theses and Dissertations

Maintenance of cancer stem cells (CSCs) is regulated by their microenvironment. As cancer cells are affected by many factors in their microenvironment, a major challenge is to isolate the effect of a specific factor on CSCs while keeping other factors unchanged. We developed a synthetic inert 3D Poly Ethylene Glycol Di-Acrylate (PEGDA) gel culture system as a unique tool to study the effect of microenvironmental factors on CSCs response. Synthetic hydrogels provide the flexibility to design three-dimensional (3D) matrices to isolate and study individual factors in the tumor microenvironment. The first objective of this work was to investigate the effect …

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Automatic Loop Tuning And Memory Management For Stencil Computations, Fan Zhang Dec 2014

Automatic Loop Tuning And Memory Management For Stencil Computations, Fan Zhang

Theses and Dissertations

The Texas Instruments C66x Digital Signal Processor (DSP) is an embedded processor technology that is targeted at real time signal processing. It is also developed with a high potential to become the new generation of coprocessor technology for high performance embedded computing. Of particular interest is its performance for stencil computations, such as those found in signal processing and computer vision tasks. A stencil is a loop in which the output value is updated at each position of an array by taking a weighted function of its neighbors. Efficiently mapping stencil-based kernels to the C66x device presents two challenges. The …

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Bio-Active Degradable Micellar Hydrogels For Osteogenic Differentiation Of Mesenchymal Stem Cells, Seyedsina Moeinzadeh Dec 2014

Bio-Active Degradable Micellar Hydrogels For Osteogenic Differentiation Of Mesenchymal Stem Cells, Seyedsina Moeinzadeh

Theses and Dissertations

A feasible approach to the restoration of injured bone tissue is the use of tissue engineering strategies to deliver mesenchymal stem cells (MSCs) to the site of regenration in degradable, in-situ gelling, bio-active hydrogels. Although inert Polyethylene glycol (PEG) hydrogels provide flexibility in controlling the cell microenvironment, their use for in vivo applications in tissue regeneration is limited by their persistence (nondegradability) in the site of regeneration. In an attempt to produce inert hydrolytically degradable matrices for encapsulation of MSCs, hydrogels based on star PEG macromonomers chain-extended with short hydroxy acid (HA) segments (SPEXA) were synthesized and characterized with respect …

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Compact Antennas And Arrays For Unmanned Air Systems, James Arthur Eck Dec 2014

Compact Antennas And Arrays For Unmanned Air Systems, James Arthur Eck

Theses and Dissertations

A simple and novel dual-CP printed antenna is modelled and measured. The patch antennais small and achieves a low axial ratio without quadrature feeding. The measured pattern showsaxial ratio pattern squinting over frequency. Possible methods of improving the individual element are discussed, as well as an array technique for improving the axial ratio bandwidth. Three endfire printed antenna structures are designed, analyzed, and compared. The comparison includes an analysis of costs of production for the antenna structures in addition to their performance parameters. This analysis concludes that cost of materials primarily reduces the size of antennas for a given gain …

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Characterization Of Smoothness In Wrist Rotations, Layne Hancock Salmond Dec 2014

Characterization Of Smoothness In Wrist Rotations, Layne Hancock Salmond

Theses and Dissertations

Smoothness is a hallmark of healthy movement and has the potential to be used as a marker of recovery in rehabilitation settings. While much past research has focused on shoulder and elbow movements (reaching), little is known about movements of the wrist despite its importance in everyday life and its impairment in many neurological and biomechanical disorders. Our current lack of knowledge regarding wrist movement prevents us from improving current models, diagnosis, and treatment of wrist disorders. In particular, while movement smoothness is a well-known characteristic of reaching movements and may potentially be used to diagnose and monitor recovery from …

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Modeling And Testing Of Bistable Waterbomb Base Configurations, Brandon Holbrook Hanna Dec 2014

Modeling And Testing Of Bistable Waterbomb Base Configurations, Brandon Holbrook Hanna

Theses and Dissertations

Origami is making an impact in engineering as solutions to problems are being found by applying origami principles (eg. flat-foldability) and using specific crease patterns as inspiration. This thesis presents an in-depth analysis of a particular origami fold -- the waterbomb base -- to facilitate its use in future engineering problems. The watebomb base is of interest due to its familiarity to the origami community, simple topology (can be made by folding a single sheet of paper four times), scalability, generalizability, and interesting kinetic behavior. It can behave as a nonlinear spring as well as a one- or two-way bistable …

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Crash Prediction Modeling For Curved Segments Of Rural Two-Lane Two-Way Highways In Utah, Casey Scott Knecht Dec 2014

Crash Prediction Modeling For Curved Segments Of Rural Two-Lane Two-Way Highways In Utah, Casey Scott Knecht

Theses and Dissertations

This thesis contains the results of the development of crash prediction models for curved segments of rural two-lane two-way highways in the state of Utah. The modeling effort included the calibration of the predictive model found in the Highway Safety Manual (HSM) as well as the development of Utah-specific models developed using negative binomial regression. The data for these models came from randomly sampled curved segments in Utah, with crash data coming from years 2008-2012. The total number of randomly sampled curved segments was 1,495. The HSM predictive model for rural two-lane two-way highways consists of a safety performance function …

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A Hybrid Method For Sensitivity Optimization With Application To Radio-Frequency Product Design, Abraham Lee Dec 2014

A Hybrid Method For Sensitivity Optimization With Application To Radio-Frequency Product Design, Abraham Lee

Theses and Dissertations

A method for performing robust optimal design that combines the efficiency of experimental designs and the accuracy of nonlinear programming (NLP) has been developed, called Search-and-Zoom. Two case studies from the RF and communications industry, a high-frequency micro-strip band-pass filter (BPF) and a rectangular, directional patch antenna, were used to show that sensitivity optimization could be effectively performed in this industry and to compare the computational efficiency of traditional NLP methods (using fmincon solver in MATLAB R2013a) and they hybrid method Search-and-Zoom. The sensitivity of the BPF's S11 response was reduced from 0.06666 at the (non-robust) nominal optimum to 0.01862 …

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Lateral Resistance Of Piles Near 15 Foot Vertical Mse Abutment Walls Reinforced With Ribbed Steel Strips, Jarell Han Dec 2014

Lateral Resistance Of Piles Near 15 Foot Vertical Mse Abutment Walls Reinforced With Ribbed Steel Strips, Jarell Han

Theses and Dissertations

ABSTRACTLateral Resistance of Piles near 15 Foot Vertical MSE AbutmentWalls Reinforced with Ribbed Steel StripsJarell Jen Chou HanDepartment of Civil and Environmental Engineering, BYUMaster of ScienceA full scale MSE wall was constructed and piles were driven at various distances behind the wall. Lateral load tests were conducted to determine the effect of pile spacing from the wall on the lateral resistance of the piles and the force resisted by the MSE reinforcement. The piles used for this study were 12.75 inch pipe piles and the reinforcements were ribbed steel strips.Load-deflection curves were developed for piles located behind the wall at …

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Kinetic Experimental And Modeling Studies On Iron-Based Catalysts Promoted With Lanthana For The High-Temperature Water-Gas Shift Reaction Characterized With Operando Uv-Visible Spectroscopy And For The Fischer-Tropsch Synthesis, Basseem Bishara Hallac Dec 2014

Kinetic Experimental And Modeling Studies On Iron-Based Catalysts Promoted With Lanthana For The High-Temperature Water-Gas Shift Reaction Characterized With Operando Uv-Visible Spectroscopy And For The Fischer-Tropsch Synthesis, Basseem Bishara Hallac

Theses and Dissertations

The structural and functional roles of lanthana in unsupported iron-based catalysts for the high-temperature water-gas shift reaction and Fischer-Tropsch synthesis were investigated. The performance of the catalysts with varying lanthana contents was based on their activity, selectivity, and stability. With regard to the former reaction, extent of reduction of the iron in Fe2O3/Cr2O3/CuO/La2O3 water-gas shift catalysts is a key parameter that was characterized using UV-visible spectroscopy. Minor addition of lanthana (<0.5 wt%) produces more active and stable catalysts apparently because it stabilizes the iron-chromium spinel, increases the surface area of the reduced catalysts, enhances the reduction of hematite to the magnetite active phase, and facilitates the adsorption of CO on the surface of the catalyst modeled by an adsorptive Langmuir-Hinshelwood mechanism. Statistical 95% confidence contour plots of the adsorption equilibrium constants show that water adsorbs more strongly than CO, which inhibits the reaction rate. A calibration curve that correlates the oxidation state of surface iron domains to normalized absorbance of visible light was successfully generated and applied to the water-gas shift catalysts. UV-visible studies indicated higher extent of reduction for surface Fe domains for the catalysts promoted with 1 wt% of lanthana and showed potential to be a more convenient technique for surface chemistry studies than X-ray absorption near edge spectroscopy (XANES). Lanthana addition to iron-based Fischer-Tropsch catalysts enhances the olefin-to-paraffin ratio, but decreases their activity, stability, and selectivity to liquid hydrocarbons. Adding lanthana at the expense of potassium reduces the water-gas shift selectivity and enhances the activity and stability of the catalysts. Finally, a model that simulates heat and mass transfer limitations on the particle scale for the Fischer-Tropsch reaction applicable at lab-scale suggests optimal operating and design conditions of 256°C, 30 bar, and 80 mirons are recommended for higher selectivity to liquid hydrocarbons. The model considers pressure drop, deactivation, pore diffusion, film heat transfer, and internal heat transfer when solving for the optimal conditions, and maps them as functions of design variables. This model can be up-scaled to provide guidance for optimal design of commercial-size reactors.

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Axial Compression Behavior Of Unidirectional Carbon/Epoxy Tubes And Rods Before And After Impact, Ian Michael Oxborrow Dec 2014

Axial Compression Behavior Of Unidirectional Carbon/Epoxy Tubes And Rods Before And After Impact, Ian Michael Oxborrow

Theses and Dissertations

Compression tests were performed on damaged and undamaged rods and tubes made from unidirectional carbon/epoxy composite and lightweight core materials. Tested samples represent local members in an open, three-dimensional, composite lattice structure. Testing was performed in order to establish effective core materials to use in order to increase the buckling length of local IsoTruss® members while maintaining low weight. Members were formed from T700SC-12K-50C carbon fiber with UF6639-100 resin. Core materials consisted of 3/8-inch (0.953 cm) outside diameter Teflon® rods, Teflon® tubes, nylon rods, nylon tubes, Ertalyte® rods, and Duratron® rods. All 3/8-inch (0.953-cm) cores were each surrounded by 50 …

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Developments In Lfm-Cw Sar For Uav Operation, Craig Lee Stringham Dec 2014

Developments In Lfm-Cw Sar For Uav Operation, Craig Lee Stringham

Theses and Dissertations

Opportunities to use synthetic aperture radar (SAR) in scientific studies and military operations are expanding with the development of small SAR systems that can be operated on small unmanned air vehicles (UAV)s. While the nimble nature of small UAVs make them an attractive platform for many reasons, small UAVs are also more prone to deviate from a linear course due autopilot errors and external forces such as turbulence and wind. Thus, motion compensation and improved processing algorithms are required to properly focus the SAR images. The work of this dissertation overcomes some of the challenges and addresses some of the …

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Shear-Dominated Bending Behavior Of Carbon/Epoxy Composite Lattice Isobeam Structures, Kirsten Bramall Hinds Dec 2014

Shear-Dominated Bending Behavior Of Carbon/Epoxy Composite Lattice Isobeam Structures, Kirsten Bramall Hinds

Theses and Dissertations

Composite lattice structures known as the IsoBeam™ made with unidirectional carbon/epoxy were manufactured and tested in shear-dominated bending. The manufacturing process consisted of placing tows of carbon fiber pre-impregnated with epoxy resin onto a pin-type mandrel to create members with interwoven joints. The members were consolidated with a half spiral aramid sleeve. The IsoBeam structure consists of two main types of members: longitudinal and diagonal members measuring nominally 0.4 in. (10.2 mm) and 0.2 in. (5.1 mm) in diameter, respectively. The hand-manufactured specimens measured nominally 6 in. (152.4 mm) high by 3 in. (76.2 mm) wide by 2 ft (0.61 …

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Evaluation Of Current Empirical Methods For Predicting Lateral Spread-Induced Ground Deformations For Large Magnitude Earthquakes Using Maule Chile 2010 Case Histories, Ginger Emily Tryon Dec 2014

Evaluation Of Current Empirical Methods For Predicting Lateral Spread-Induced Ground Deformations For Large Magnitude Earthquakes Using Maule Chile 2010 Case Histories, Ginger Emily Tryon

Theses and Dissertations

Improving seismic hazard analysis is an important part of building safer structures and protecting lives. Since large magnitude earthquakes are rarer than other earthquakes, it is harder to model seismic hazards such as lateral spread displacements for these events. Engineers are often required to extrapolate current lateral spreading models when designing utilities, bridges, and piers to withstand the ground displacements caused by earthquakes with magnitudes larger than 8.0. This study uses three case histories from the Maule Chile 2010 earthquake (Mw =8.8) to develop recommendations on which models are most accurate for large earthquake events and how to improve the …

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Investigating The Relationship Between High Temperature Flow Stress And Friction Stir Weldability In Hsla Steels, David Jordan Walser Dec 2014

Investigating The Relationship Between High Temperature Flow Stress And Friction Stir Weldability In Hsla Steels, David Jordan Walser

Theses and Dissertations

The feed rate at which a defect free friction stir weld can be run (friction stir weldability) on an HSLA steel plate can vary widely between heats that meet the same specified physical properties. Consequently, every time a new heat of HSLA steel is obtained, exploratory welds must be run to determine the proper feed rate for that plate. Previous research suggests that the varying levels of alloying elements related to high temperature physical properties between the different heats causes the observed change in friction stir weldability. Because of this, it was hypothesized that the high temperature physical properties of …

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Latin American Data Drought: An Assessment Of Available River Observation Data In Select Latin American Countries And Development Of A Web-Based Application For A Hydrometerological Database System In Spanish, Stephen Joseph Bolster Dec 2014

Latin American Data Drought: An Assessment Of Available River Observation Data In Select Latin American Countries And Development Of A Web-Based Application For A Hydrometerological Database System In Spanish, Stephen Joseph Bolster

Theses and Dissertations

The demand and collection of hydrometeorological data is growing to support hydrologic and hydraulic analyses, and other studies. These data can amount to extensive information that requires sound data management to enable efficient storage, access, and use. While much of the globe is using technology to efficiently collect and store hydrometeorological data, other parts, such as developing countries, are unable to do so. This thesis presents an assessment of available river observations data in Latin American countries in Central America and the Caribbean. The assessment analyzes 1) access to available data, 2) spatial density of data, and 3) the temporal …

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Tincr: Integrating Custom Cad Tool Frameworks With The Xilinx Vivado Design Suite, Brad S. White Dec 2014

Tincr: Integrating Custom Cad Tool Frameworks With The Xilinx Vivado Design Suite, Brad S. White

Theses and Dissertations

The field programmable gate array (FPGA) is appealing as a computational platform because of its ability to be repurposed for a number of different applications and its relatively low design cost. Traditionally, FPGA vendors provide a set of electronic design automation (EDA) tools to assist customers with the implementation of their designs. These tools are necessarily general purpose, and the resulting tool flow does not provide the user much in the way of customization. Frameworks such as RapidSmith and Torc allow for the creation of custom CAD tools that are able to target actual Xilinx FPGA devices. However, they are …

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Design And Implementation Of An Inverse Modeling Framework Using The Method Of Anchored Distributions, Carlos Andres Osorio Murillo Dec 2014

Design And Implementation Of An Inverse Modeling Framework Using The Method Of Anchored Distributions, Carlos Andres Osorio Murillo

Theses and Dissertations

Estimation of spatial random fields (SRFs) such as transmissivity or porosity is required for predicting groundwater flow and subsurface contaminant movement. Similarly, distributed parameter fields such as terrain roughness and evapotranspiration coefficients are required by other areas of environmental and earth sciences modeling. This dissertation presents an inverse modeling framework for characterizing SRFs called MAD#, which is an end-user software implementation of the Bayesian inverse modeling technique Method of Anchored Distributions (MAD). The MAD# framework allows modelers to “wrap” existing simulation modeling tools using an extensible driver architecture that exposes model parameters to the inversion engine. A compelling aspect of …

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Light Field Imaging Applied To Reacting And Microscopic Flows, Jonathon Remy Pendlebury Dec 2014

Light Field Imaging Applied To Reacting And Microscopic Flows, Jonathon Remy Pendlebury

Theses and Dissertations

Light field imaging, specifically synthetic aperture (SA) refocusing is a method used to combine images from an array of cameras to generate a single image with a narrow depth of field that can be positioned arbitrarily throughout the volume under investigation. Creating a stack of narrow depth of field images at varying locations generates a focal stack that can be used to find the location of objects in three dimensions. SA refocusing is particularly useful when reconstructing particle fields that are then used to determine the movement of the fluid they are entrained in, and it can also be used …

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Effect Of Thermal Treatments On Mechanical Properties And Bioactivity Of Third Generation Of Bioactive Glass. A Step For Commercialization Success Of Third Generation Bioactive Glasses, Rajan Pandya Dec 2014

Effect Of Thermal Treatments On Mechanical Properties And Bioactivity Of Third Generation Of Bioactive Glass. A Step For Commercialization Success Of Third Generation Bioactive Glasses, Rajan Pandya

Theses and Dissertations

Unavailability of donors for transplanting bone to help people with orthopedic imparities gave rise to the metal implants that could be made in factories. This seemed like a good solution as it was available to all the people who needed it. It came with limitations such as restricted movement, infection, wear and tear of the surrounding tissue, and rejection. Biologically active implants were introduced by Dr. Larry Hench in 1960s [12]. The field of regenerative medicine has been changing rapidly since then. Biologically active implants facilitate bone regeneration and do not harm the surrounding tissue in any way. The bioactive …

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Optimized Photogrammetric Network Design With Flight Path Planner For Uav-Based Terrain Surveillance, Ivan Yair Rojas Dec 2014

Optimized Photogrammetric Network Design With Flight Path Planner For Uav-Based Terrain Surveillance, Ivan Yair Rojas

Theses and Dissertations

This work demonstrates the use of genetic algorithms as a stochastic optimization technique for developing a camera network design and the flight path for photogrammetricapplications using Small Unmanned Aerial Vehicles. This study develops a Virtual Optimizer for Aerial Routes (VOAR) as a new photogrammetric mapping tool for acquisition of images to be used in 3D reconstruction. 3D point cloud models provide detailed information on infrastructure from places where human access may be difficult. This algorithm allows optimized flight paths to monitor infrastructure using GPS coordinates and optimized camera poses ensuring that the set of images captured is improved for 3D …

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Lateral-Torsional Buckling Capacity Of Tapered-Flange Moment Frame Shapes, Leah O'Neill Dec 2014

Lateral-Torsional Buckling Capacity Of Tapered-Flange Moment Frame Shapes, Leah O'Neill

Theses and Dissertations

While moment frames are a popular lateral-force resisting system, their constant cross-section can lead to inefficiencies in energy absorption and stiffness. By tapering the flange width linearly toward the center of the beam length, the energy absorption efficiency can be increased, leading to a better elastic response from the beam and more elastic stiffness per pound of steel used. Lateral-torsional buckling is an important failure mode to be considered for tapered-flange moment frame shapes. No closed-form or finite element solutions have yet been developed for tapered-flange I-beams with a non-uniform, linear moment gradient and intermediate bracing conditions. In this study, …

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Full-Scale Testing Of Blast-Induced Liquefaction Downdrag On Auger-Cast Piles In Sand, Joseph Erick Hollenbaugh Dec 2014

Full-Scale Testing Of Blast-Induced Liquefaction Downdrag On Auger-Cast Piles In Sand, Joseph Erick Hollenbaugh

Theses and Dissertations

Deep foundations like auger-cast piles and drilled shafts frequently extend through liquefiable sand layers and bear on non-liquefiable layers at depth. When liquefaction occurs, the skin friction on the shaft decreases to zero, and then increases again as the pore water pressure dissipates and the layer begins to settle, or compact. As the effective stress increases and the liquefiable layer settles, along with the overlaying layers, negative skin from the soil acts on the shaft. To investigate the loss of skin friction and the development of negative skin friction, soil-induced load was measured in three instrumented, full-scale auger-cast piles after …

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Lateral Resistance Of Piles Near Vertical Mse Abutment Walls, Cody Hatch Dec 2014

Lateral Resistance Of Piles Near Vertical Mse Abutment Walls, Cody Hatch

Theses and Dissertations

A full scale MSE wall was constructed and piles were driven at various distances behind the wall. Lateral load testing was conducted and the performance of the pile, wall, and reinforcement were measured. The piles were 12.75 inch pipe piles, and the wall was reinforced with welded wire grid reinforcement. The objective of the testing was to characterize the relationship between the lateral pile resistance and the distance of the pile behind the back face of the MSE wall. Load-displacement curves are presented for the piles located behind the wall at 66 inches (5.3 diameters), 55 inches (4.3 diameters), 41 …

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A Variable-Stiffness Compliant Mechanism For Stiffness-Controlled Haptic Interfaces, Jeffrey C. Hawks Dec 2014

A Variable-Stiffness Compliant Mechanism For Stiffness-Controlled Haptic Interfaces, Jeffrey C. Hawks

Theses and Dissertations

In this research a variable-stiffness compliant mechanism was developed to generate variable force-displacement profiles at the mechanisms coupler point. The mechanism is based on a compliant Roberts straight-line mechanism, and the stiffness is varied by changing the effective length of the compliant links with an actuated slider. The variable-stiffness mechanism was used in a one-degree-of-freedom haptic interface to demonstrate the effectiveness of varying the stiffness of a compliant mechanism. Unlike traditional haptic interfaces, in which the force is controlled using motors and rigid links, the haptic interface developed in this work displays haptic stiffness via the variable-stiffness compliant mechanism. The …

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Analysis, Validation, And Improvement Of High-Resolution Wind Estimates From The Advanced Scatterometer (Ascat), Jeffrey Richard Blodgett Dec 2014

Analysis, Validation, And Improvement Of High-Resolution Wind Estimates From The Advanced Scatterometer (Ascat), Jeffrey Richard Blodgett

Theses and Dissertations

The standard L2B ocean wind product from the Advanced Scatterometer (ASCAT) is retrieved as a 25 km product on a 12.5 km grid. Ultra-high resolution (UHR) processing allows ASCAT wind retrieval on a high-resolution 1.25 km grid. Ideally, such a high-resolution sample grid provides wind information down to a 2.5 km scale, allowing better analysis of winds with high spatial variability such as those in near-coastal regions and storms. Though the wind field is sampled on a finer grid, the actual data resolution needs to be validated. This thesis provides an analysis and validation of ASCAT UHR wind estimates in …

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Magnetic Holding Of Synthetic Quartz For Precision Grinding, Saudin Basic Dec 2014

Magnetic Holding Of Synthetic Quartz For Precision Grinding, Saudin Basic

Theses and Dissertations

The objective of this research work is to investigate the practicality of magnetic workholding of non-magnetic synthetic quartz during high-speed grinding. This research work is sponsored by Quartzdyne and will be used as the starting point to applying single-piece rounding of its quartz. Hypotheses were created that would permit the authors to conclude that magnets are in fact worthwhile workholders for non-magnetic materials. Designs of Experiments were used to reject or fail to reject the null hypotheses. Experiments were carried out using a custom HAAS lathe, modified into a grinding center with an NSK live spindle, and neodymium-iron-boron magnets used …

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