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Full-Text Articles in Engineering

Performance Analysis Of Effective Range And Orientation Of Uhf Passive Rfid, Paul N. Roque Jun 2008

Performance Analysis Of Effective Range And Orientation Of Uhf Passive Rfid, Paul N. Roque

Theses and Dissertations

The purpose of this research is to characterize the performance of UHF passive RFID tags. Factors of importance are the impact of tag orientation and distance from the RFID reader. Within this study, a comprehensive literature review of RFID technology is presented as well as the methodology used for the research. Furthermore, an analysis of RFID tag experiments is discussed and the results reviewed. To accomplish this task, two main objectives have been established as goals for the study. The first objective is to determine an optimum tag orientation within the RFID reader’s normal read range. Once the optimum tag …

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Evaluation Of Laboratory Durability Tests For Stabilized Subgrade Soils, John Wesley Parker May 2008

Evaluation Of Laboratory Durability Tests For Stabilized Subgrade Soils, John Wesley Parker

Theses and Dissertations

The Portland Cement Association commissioned a research project at Brigham Young University to compare selected laboratory durability tests available for assessing stabilized subgrade materials. Improved understanding of these tests is needed to enable more objective selection of durability tests by design engineers and to facilitate more meaningful comparisons of data obtained for different stabilizer treatments using different evaluation procedures. The laboratory research associated with this project involved two subgrade materials, four stabilizers at three concentrations each, and three durability tests in a full-factorial experimental design. The two subgrade soils used were a silty sand and a lean clay, while the …

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An Investigation Of Positive Engagement, Continuously Variable Transmissions, Ryan R. Dalling May 2008

An Investigation Of Positive Engagement, Continuously Variable Transmissions, Ryan R. Dalling

Theses and Dissertations

A Positive Engagement, Continuously Variable Transmission (PECVT) allows for a continuously variable transmission ratio over a given range using positively engaged members, such as gear teeth, to transmit torque. This research is an investigation of PECVTs to establish a classification system and governing principles that must be satisfied for an embodiment to overcome the non-integer tooth problem. Results of an external patent search are given as examples of different concepts and PECVT embodiments that have been employed to negate the effects of the non-integer tooth problem. To classify all published and unpublished PECVT embodiments, a classification system is developed, based …

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Impact Of Jet Grouting On The Lateral Strength Of Soil Surrounding Driven Pile Foundations, Matthew E. Adsero Apr 2008

Impact Of Jet Grouting On The Lateral Strength Of Soil Surrounding Driven Pile Foundations, Matthew E. Adsero

Theses and Dissertations

Jet grouting was used to strengthen the soft soil surrounding the piles and the pile cap of two full-scale driven pile foundations. Soilcrete columns, created by jet grouting, were placed underneath the pile cap and surrounding the piles of the first foundation. Two rows of soilcrete columns were placed around the perimeter of one-side of the second. All of the jet grouting took place after construction of the pile caps. Laboratory testing of the soilcrete slurry showed the columns as having a design unconfined compressive strength of 550-650 psi, compared with the native soil strength of only 6-8 psi (850-1150 …

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Stabilization And Control Of A Quad-Rotor Micro-Uav Using Vision Sensors, Spencer G. Fowers Apr 2008

Stabilization And Control Of A Quad-Rotor Micro-Uav Using Vision Sensors, Spencer G. Fowers

Theses and Dissertations

Quad-rotor micro-UAVs have become an important tool in the field of indoor UAV research. Indoor flight poses problems not experienced in outdoor applications. The ability to be location- and movement-aware is paramount because of the close proximity of obstacles (walls, doorways, desks). The Helio-copter, an indoor quad-rotor platform that utilizes a compact FPGA board called Helios has been developed in the Robotic Vision Lab at Brigham Young University. Helios allows researchers to perform on-board vision processing and feature tracking without the aid of a ground station or wireless transmission. Using this on-board feature tracking system a drift stabilization control system …

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Real-Time Implementation Of Vision Algorithm For Control, Stabilization, And Target Tracking For A Hovering Micro-Uav, Beau J. Tippetts Apr 2008

Real-Time Implementation Of Vision Algorithm For Control, Stabilization, And Target Tracking For A Hovering Micro-Uav, Beau J. Tippetts

Theses and Dissertations

A lightweight, powerful, yet efficient quad-rotor platform was designed and constructed to obtain experimental results of completely autonomous control of a hovering micro-UAV using a complete on-board vision system. The on-board vision and control system is composed of a Helios FPGA board, an Autonomous Vehicle Toolkit daughterboard, and a Kestrel Autopilot. The resulting platform is referred to as the Helio-copter. An efficient algorithm to detect, correlate, and track features in a scene and estimate attitude information was implemented with a combination of hardware and software on the FPGA, and real-time performance was obtained. The algorithms implemented include a Harris feature …

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Measurements And Modeling Of Coal Ash Deposition In An Entrained-Flow Reactor, Ryan P. Blanchard Apr 2008

Measurements And Modeling Of Coal Ash Deposition In An Entrained-Flow Reactor, Ryan P. Blanchard

Theses and Dissertations

Coal plays a significant role in meeting the world's need for energy and will continue to do so for many years to come. Economic, environmental, and public opinion are requiring coal derived energy to be cleaner and operate in a more narrow window of operating conditions. Fouling and slagging of heat transfer surfaces continues to be a challenge for maintaining boiler availability and expanding the use of available fuels and operating conditions. The work incorporates existing information in the literature on ash deposition into a User-Defined Function (UDF) for a commercial comprehensive combustion and CFD code. Results from the new …

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Parametric Optimization Design System For A Fluid Domain Assembly, Matthew Jackson Fisher Apr 2008

Parametric Optimization Design System For A Fluid Domain Assembly, Matthew Jackson Fisher

Theses and Dissertations

Automated solid modeling, integrated with computational fluid dynamics (CFD) and optimization of a 3D jet turbine engine has never been accomplished. This is due mainly to the computational power required, and the lack of associative parametric modeling tools and techniques necessary to adjust and optimize the design. As an example, the fluid domain of a simple household fan with three blades may contain 500,000 elements per blade passage. Therefore, a complete turbine engine that includes many stages, with sets of thirty or more blades each, will have hundreds of millions of elements. The fluid domains associated with each blade creates …

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Development Of A Miniature Vtol Tail-Sitter Unmanned Aerial Vehicle, Jeffrey V. Hogge Apr 2008

Development Of A Miniature Vtol Tail-Sitter Unmanned Aerial Vehicle, Jeffrey V. Hogge

Theses and Dissertations

The design, analysis, construction and flight testing of a miniature Vertical Take-Off and Landing (VTOL) tail-sitter Unmanned Aerial Vehicle (UAV) prototype is presented in detail. Classic aircraft design methods were combined with numerical analysis to estimate the aircraft performance and flight characteristics. The numerical analysis employed a propeller blade-element theory coupled with momentum equations to predict the influence of a propeller slipstream on the freestream flow field, then the aircraft was analyzed using 3-D vortex lifting-line theory to model finite wings immersed in the flow field. Four prototypes were designed, built, and tested and the evolution of these prototypes is …

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The Effect Of Elevated Temperature On The Fretting Fatigue Behavior Of Nickel Alloy In-100, John F. Ownby Apr 2008

The Effect Of Elevated Temperature On The Fretting Fatigue Behavior Of Nickel Alloy In-100, John F. Ownby

Theses and Dissertations

This thesis studied the effect of elevated temperature (600 C) on the fretting fatigue behavior of IN-100. First, fretting and plain fatigue S-N curves were determined over a large range of applied stress at an identical stress ratio of 0.03 at 600 C and for fretting tests, with a constant contact load. The partial slip condition was verified by using hysteresis between shear force and axial stress techniques. The contact width and the crack initiation location were observed for all of the fretting specimens. The contact widths were consistent with expected values and the crack initiation location was at the …

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Nrcs Curve Number Calibration Using Usgs Regression Equations, Charlotte M. Mecham Apr 2008

Nrcs Curve Number Calibration Using Usgs Regression Equations, Charlotte M. Mecham

Theses and Dissertations

The Curve Number (CN) method of estimating the direct runoff response to rainfall events was originally developed in the 1950's primarily for agricultural purposes in the mid-western United States. The accuracy of the CN method is greatly affected by variation of the soil type and land use of the region. Curve Numbers developed for a given region are not appropriate for application in other regions. In order to produce reliable, consistent results, Curve Numbers must be calibrated for the area in which the CN method is to be applied. Calibration is ideally accomplished by direct measurement using several rain and …

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Exploring The Common Design Space Of Dissimilar Assembly Parameterizations For Interdisciplinary Design, Brady M. Larson Apr 2008

Exploring The Common Design Space Of Dissimilar Assembly Parameterizations For Interdisciplinary Design, Brady M. Larson

Theses and Dissertations

The use of parametric CAD models in engineering, analysis, and optimization has greatly enhanced the effectiveness and efficiency of the product development process. Parametric models provide an attractive avenue for expansive design exploration. There still exists, however, a great challenge for products requiring design input from multiple disciplines. The collaboration of engineering disciplines can be hampered by many factors including: competing design objectives, communication of design changes, the use of different design and analysis software, and different geometry definitions. These obstacles become compounded when developing products at the assembly level. The use of solid parametric assembly models is not readily …

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Generating Cad Parametric Features Based On Topology Optimization Results, William R. Blattman Apr 2008

Generating Cad Parametric Features Based On Topology Optimization Results, William R. Blattman

Theses and Dissertations

Shape optimization has become an important tool in industry to minimize weight and generate new designs. At the same time, companies are turning to CAD-centric design strategies where robust parametric CAD models are used to generate new designs and part-families of current designs, as well as the tooling and manufacturing procedures. However, due to its complexity, the optimal topology results are often discarded or recreated by hand into a CAD model. From a design stand point, the results can be improved with the use of manufacturing constraints on the shape optimization process. These constraints improve the manufacturability based on common …

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Numerical Analysis Of Passive Force On Skewed Bridgeabutments With Reinforced Concrete Wingwalls, Scott Karl Snow Apr 2008

Numerical Analysis Of Passive Force On Skewed Bridgeabutments With Reinforced Concrete Wingwalls, Scott Karl Snow

Theses and Dissertations

Numerical Analysis of Passive Force on Skewed BridgeAbutments with Reinforced Concrete WingwallsScott Karl SnowDepartment of Civil and Environmental Engineering, BYU Master of Science Historically bridges with skewed abutments have proven more likely to fail during earthquake loadings (Toro et al, 2013) when compared to non-skewed bridges (Apirakvorapinit et al. 2012; Elnashai et al. 2010). Previous studies including small-scale laboratory tests by Jessee (2012), large-scale field tests by Smith (2014), and numerical modeling by Shamsabadi et al. (2006) have shown that 45° skewed bridge abutments experience a reduction in peak passive force by about 65%. With numerous skewed bridges in the …

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Applying Frequency-Domain Equalization To Code-Division Multiple Access And Transform-Domain Communications Systems, Alfred A. Tamayo Iii Mar 2008

Applying Frequency-Domain Equalization To Code-Division Multiple Access And Transform-Domain Communications Systems, Alfred A. Tamayo Iii

Theses and Dissertations

This research examined the theory and application of using orthogonal frequency division multiplexing (OFDM), or discrete multi-tone (DMT), frequency domain equalization (FEQ) with two communications systems that inherently possess unused carrier frequencies, or null-tones, in their respective transmission frequencies. The fundamental DMT-FEQ property relies on null-tones to equalize a non-ideal channel and mitigate the effects of interchannel interference (ICI), intersymbol interference (ISI), and noise. The two communications systems investigated were a Hadamard encoded code division multiple access (CDMA) communications system with up to 32 synchronous users and a transform domain communications system (TDCS) with only one user. Both communications systems …

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Multi-Objective Optimization Of Mixed-Variable, Stochastic Systems Using Single-Objective Formulations, Todd J. Paciencia Mar 2008

Multi-Objective Optimization Of Mixed-Variable, Stochastic Systems Using Single-Objective Formulations, Todd J. Paciencia

Theses and Dissertations

Many problems exist where one desires to optimize systems with multiple, often competing, objectives. Further, these problems may not have a closed form representation, and may also have stochastic responses. Recently, a method expanded mixed variable generalized pattern search/ranking and selection (MVPS-RS) and Mesh Adaptive Direct Search (MADS) developed for single-objective, stochastic problems to the multi-objective case by using aspiration and reservation levels. However, the success of this method in approximating the true Pareto solution set can be dependent upon several factors. These factors include the experimental design and ranges of the aspiration and reservation levels, and the approximation quality …

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Improved Feature Extraction, Feature Selection, And Identification Techniques That Create A Fast Unsupervised Hyperspectral Target Detection Algorithm, Robert J. Johnson Mar 2008

Improved Feature Extraction, Feature Selection, And Identification Techniques That Create A Fast Unsupervised Hyperspectral Target Detection Algorithm, Robert J. Johnson

Theses and Dissertations

This research extends the emerging field of hyperspectral image (HSI) target detectors that assume a global linear mixture model (LMM) of HSI and employ independent component analysis (ICA) to unmix HSI images. Via new techniques to fully automate feature extraction, feature selection, and target pixel identification, an autonomous global anomaly detector, AutoGAD, has been developed for potential employment in an operational environment for real-time processing of HSI targets. For dimensionality reduction (initial feature extraction prior to ICA), a geometric solution that effectively approximates the number of distinct spectral signals is presented. The solution is based on the theory of the …

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Tightly Integrating Optical And Inertial Sensors For Navigation Using The Ukf, Sedat Ebcin Mar 2008

Tightly Integrating Optical And Inertial Sensors For Navigation Using The Ukf, Sedat Ebcin

Theses and Dissertations

The motivation of this research is to address the benefits of tightly integrating optical and inertial sensors where GNSS signals are not available. The research begins with describing the navigation problem. Then, error and measurement models are presented. Given a set of features, a feature detection and projection algorithm is developed which utilizes inertial measurements to predict vectors in the feature space between images. The unscented Kalman filter is applied to the navigation system using the inertial measurements and feature matches to estimate the navigation trajectory. Finally, the image-aided navigation algorithm is tested using a simulation and an experiment. As …

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Neutron Detection Utilizing Gadolinium Doped Hafnium Oxide Films, Bryan D. Blasy Mar 2008

Neutron Detection Utilizing Gadolinium Doped Hafnium Oxide Films, Bryan D. Blasy

Theses and Dissertations

Gadolinium (Gd) doped hafnium oxide (HfO2) was deposited onto a silicon substrate using pulsed laser deposition. Synchrotron radiation was used to perform Gd L3-edge extended X-ray absorption fine structure (EXAFS) measurements on 3%, 10%, and 15% doped HfO2 samples. The interatomic distances determined from Fourier transformation and fitting the data show Gd occupying the hafnium site in the HfO2 lattice, there was no clustering of Gd atoms, and the Gd ion retains monoclinic local symmetery for all levels of doping. Current as a function of voltage experiments identified the films as having poor diode characteristics with …

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Evaluating The Response Of Polyvinyl Toluene Scintillators Used In Portal, Kelly D. Rakes Mar 2008

Evaluating The Response Of Polyvinyl Toluene Scintillators Used In Portal, Kelly D. Rakes

Theses and Dissertations

The goal of this research work was to determine if there exists, and to what extent, variability in the pulse-height spectrum, and resolution produced by ɤ-photon induced scintillation events in polyvinyl toluene scintillators. Scintillator panels of the same type as those used in portal detector units currently operated by the Department of Homeland Security, made of polyvinyl toluene and measuring 12 x 15 x 2 in were purchased from three vendors. Each vendor supplied two scintillators, one wrapped by the vendor with aluminum foil coated mylar, and two unwrapped. The scintillators where exposed to an ≈ 8µCi source collimated …

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Impact Of Mass Mixing On The Lateral Resistance Of Driven-Pile Foundations, Mark Alan Herbst Mar 2008

Impact Of Mass Mixing On The Lateral Resistance Of Driven-Pile Foundations, Mark Alan Herbst

Theses and Dissertations

Although it has been established that in-situ soil mixing has improved the bearing capacity of soils, additional research is needed to better understand the effect of soil mixing on lateral resistance of pile caps. To do this, in-situ soil mixing was used to strengthen weak clay adjacent to a pile cap of a driven pile foundation. The mass stabilization method or mass mixing was used to treat an 11 ft wide, 4 ft thick, and 10 ft deep zone consisting of an average 475 psf clay that was adjacent to a 9-pile group in 3x3 pile configuration capped with a …

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Development Of A Screening Tool To Facilitate Technology Of An Innovative Technology To Treat Perchlorate-Contaminated Water, Daniel A. Craig Mar 2008

Development Of A Screening Tool To Facilitate Technology Of An Innovative Technology To Treat Perchlorate-Contaminated Water, Daniel A. Craig

Theses and Dissertations

Perchlorate contamination of drinking water is a significant problem nationwide. The purpose of this study was to develop a tool to predict the cost and performance of tailored granular activated carbon (T-GAC), an innovative technology that is being evaluated as a cost-effective treatment for perchlorate-contaminated water. The ability to accurately predict performance and cost can facilitate the transfer and commercialization of innovative technologies. In the study, a model was developed to predict T-GAC performance and life-cycle costs for removing perchlorate under varying influent water quality and technology operating conditions. The model's design parameters were obtained from laboratory rapid small-scale column …

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A System Dynamic Model Of Leader Emergence, Paul S. Wever Mar 2008

A System Dynamic Model Of Leader Emergence, Paul S. Wever

Theses and Dissertations

The purpose of this thesis is to develop a system dynamics model of leader emergence. Longitudinal social network and personality data were collected in a class of enlisted military professionals attending a 6-week leadership development course. Findings support known relationships in existing leadership research. The thesis demonstrates the applicability of system dynamics toward the complex social phenomena of leader emergence.

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Characterization Of Synthetic, Self-Oscillating Vocal Fold Models, James S. Drechsel Mar 2008

Characterization Of Synthetic, Self-Oscillating Vocal Fold Models, James S. Drechsel

Theses and Dissertations

The vocal folds are essential for speech production, and a better understanding of vocal fold vibration characteristics may help improve treatments of voice disorders. However, studying real vocal folds presents significant challenges. In-vivo studies are limited by access and safety issues. Excised larynges have a short useable lifetime (on the order of minutes) and are difficult to parameterize. In contrast, synthetic vocal fold models have long useable lifetimes and can be easily parameterized. In this thesis, a series of tests performed on recently developed synthetic, self-oscillating models of the human vocal folds are discussed. These tests include measurements of vibration …

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Nano-Mechanical Properties Of Heat Inactivated Bacillus Anthracis And Bacillus Thuringiensis Spores, Jessica L. Poindexter Mar 2008

Nano-Mechanical Properties Of Heat Inactivated Bacillus Anthracis And Bacillus Thuringiensis Spores, Jessica L. Poindexter

Theses and Dissertations

B. thuringiensis spores must have similar properties to B. anthracis spores to be a good simulant in counter-proliferation studies. In particular, they must behave in a similar way when exposed to high temperatures for short periods of time as would be caused by an explosion. This research project compares surface elasticities for four different spore sample types, B. anthracis spores, heat inactivated B. anthracis spores, B. thuringiensis spores, and heat inactivated B. thuringiensis spores. Heat inactivated spores were exposed to a temperature just high enough that no spores were observed to germinate. Elasticity values for the spore surfaces were determined …

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Improving Mixed Variable Optimization Of Computational And Model Parameters Using Multiple Surrogate Functions, David Bethea Mar 2008

Improving Mixed Variable Optimization Of Computational And Model Parameters Using Multiple Surrogate Functions, David Bethea

Theses and Dissertations

This research focuses on reducing computational time in parameter optimization by using multiple surrogates and subprocess CPU times without compromising the quality of the results. This is motivated by applications that have objective functions with expensive computational times at high fidelity solutions. Applying, matching, and tuning optimization techniques at an algorithm level can reduce the time spent on unprofitable computations for parameter optimization. The objective is to recover known parameters of a flow property reference image by comparing to a template image that comes from a computational fluid dynamics simulation, followed by a numerical image registration and comparison process. Mixed …

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Factors Leading To Effectiveness And Satisfaction In Civil Engineer Information Systems, Donald C. Crabtree Mar 2008

Factors Leading To Effectiveness And Satisfaction In Civil Engineer Information Systems, Donald C. Crabtree

Theses and Dissertations

The Air Force Civil Engineer Support Agency (AFCESA) has developed information systems in support of civil engineer operations. Over the last decade, the number of systems has grown to support the breadth of civil engineer functions. At this time, numerous (900+) decentralized systems support civil engineer functions around the world. Due to budget constraints, AFCESA is transforming civil engineer business processes to leverage the workforce in an optimized fashion. In support of this transition, AFCESA is posturing to acquire new information systems in support of civil engineer business processes. To help AFCESA improve upon its suite of information systems development …

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Selecting The Best Thermal Building Insulation Using A Multi-Attribute Decision Model, Theodore J. Sotoropolis Mar 2008

Selecting The Best Thermal Building Insulation Using A Multi-Attribute Decision Model, Theodore J. Sotoropolis

Theses and Dissertations

Thermal building insulation has traditionally been viewed as a means to reduce thermal conductivity through the building envelope. Builders typically choose the least expensive material which meets the specifications in order to remain competitive. Other factors regarding long term health and environmental consequences are typically dismissed. However, a recent shift toward sustainability requires that architects and engineers take a more responsible approach to building design. This research takes a holistic approach to selecting thermal building insulation through the use of a multi-attribute decision model. Several types of insulating products from a variety of manufacturers were investigated in order to determine …

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Micro-Etched Platforms For Thermal Inactivation Of Bacillus Anthracis And Bacillus Thuringiensis Spores, Leslie S. Hawkins Mar 2008

Micro-Etched Platforms For Thermal Inactivation Of Bacillus Anthracis And Bacillus Thuringiensis Spores, Leslie S. Hawkins

Theses and Dissertations

This research developed and applied microlithography techniques to etch microscope slide platforms in order to measure thermal inactivation of Bacillus thuringiensis and Bacillus anthracis spores, two closely related Bacillus species. B.t. is widely used as a surrogate for B.a. in response studies and in some field studies. This work addressed the previously identified problem of measuring both spore growth and spore thermal kill threshold using the traditional method of spreading a diluted spore solution on a plate. The micro-etched platforms forced spore separation thereby preventing neighbor growth from obscuring germination and initial vegetative growth measurements using a microscope. The technique …

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Liquefaction Mitigation Using Vertical Composite Drains And Liquefaction Induced Downdrag On Piles: Implications For Deep Foundation Design, Spencer R. Strand Mar 2008

Liquefaction Mitigation Using Vertical Composite Drains And Liquefaction Induced Downdrag On Piles: Implications For Deep Foundation Design, Spencer R. Strand

Theses and Dissertations

Deep foundations constructed in liquefiable soils require specialized design. The design engineer of such foundations must consider the effects of liquefaction on the foundation and overlying structure, such as excessive settlement, loss of skin friction at the soil-pile interface, and the development of downdrag on the pile. Controlled blasting was employed to liquefy a loose, saturated sand in order to test the liquefaction prevention capabilities of full-scale, vertical composite earthquake (EQ) drains and to investigate the development of downdrag on full-scale test piles. Blasting produced liquefaction at a test site without EQ drains which eventually resulted in 270 mm of …

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