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Articles 1 - 30 of 102
Full-Text Articles in Engineering
Active Noise Control Of A Two-Fan Exhaust-Mounted Array Using Near-Field Control Sources And Error Sensors, Ryan Leonard Rust
Active Noise Control Of A Two-Fan Exhaust-Mounted Array Using Near-Field Control Sources And Error Sensors, Ryan Leonard Rust
Theses and Dissertations
Multiple fans are sometimes used in an array configuration to cool various types of electronic equipment. In addition to adding another noise source, using two fans with closely spaced blade passage frequencies (BPF) can create an annoying beat frequency. A two fan array with each fan having a different BPF was considered. The fans were theoretically modeled at the BPF and first harmonics. Each fan has two acoustic paths to the far field. Thus, each fan was modeled as a two source array. The first control configuration consisted of one control filter using six control sources and six error sensors …
Scanning Laser Registration And Structural Energy Density Based Active Structural Acoustic Control, Daniel Alan Manwill
Scanning Laser Registration And Structural Energy Density Based Active Structural Acoustic Control, Daniel Alan Manwill
Theses and Dissertations
To simplify the measurement of energy-based structural metrics, a general registration process for the scanning laser doppler vibrometer (SLDV) has been developed. Existing registration techniques, also known as pose estimation or position registration, suffer from mathematical complexity, instrument specificity, and the need for correct optimization initialization. These difficulties have been addressed through development of a general linear laser model and hybrid registration algorithm. These are applicable to any SLDV and allow the registration problem to be solved using straightforward mathematics. Additionally, the hybrid registration algorithm eliminates the need for correct optimization initialization by separating the optimization process from solution selection. …
Eit, Slow Light, And Sealing Methods For Embedding Rubidium Into The Arrow System, Katherine Barnett Hurd
Eit, Slow Light, And Sealing Methods For Embedding Rubidium Into The Arrow System, Katherine Barnett Hurd
Theses and Dissertations
Light-matter interactions are fundamentally based on the quantum mechanical principles that govern photons, electrons and other fundamental particles. One very interesting phenomenon within all of light-matter interactions is Electromagnetically Induced Transparency(EIT). This phenomenon causes an otherwise absorbing atomic transition to stop absorbing through quantum mechanical interference of probability wave functions. Corresponding to that change in absorption, will be a sudden, large change in the index of refraction. This change in the index of refraction leads to another phenomenon in which the group velocity of light can be slowed down dramatically. In the past, many researchers have been able to achieve …
Joining Polycrystalline Cubic Boron Nitride And Tungsten Carbide By Partial Transient Liquid Phase Bonding, Grant O. Cook Iii
Joining Polycrystalline Cubic Boron Nitride And Tungsten Carbide By Partial Transient Liquid Phase Bonding, Grant O. Cook Iii
Theses and Dissertations
Friction stir welding (FSW) of steel is often performed with an insert made of polycrystalline cubic boron nitride (PCBN). Specifically, MS80 is a grade of PCBN made by Smith MegaDiamond that has been optimized for the FSW process. The PCBN insert is attached to a tungsten carbide (WC) shank by a compression fitting. However, FSW tools manufactured by this method inevitably fail by fracture in the PCBN. Permanently bonding PCBN to WC would likely solve the fracturing problem and increase the life of PCBN FSW tools to be economically viable. Partial transient liquid phase (PTLP) bonding, a process used to …
The Use Of Building Information Modeling In Generating Hard Bid Estimates, Peter Samuel Jensen
The Use Of Building Information Modeling In Generating Hard Bid Estimates, Peter Samuel Jensen
Theses and Dissertations
Building Information Modeling has provided many benefits to the architectural, engineering, construction and facilities management communities. Many studies have been done to validate the asserted benefits, including benefits to the field of estimating. The studies on estimating are currently limited to the realm of conceptual estimates, and have only treated detailed estimates in the abstract. The purpose of this study was to determine how BIM was being used by companies in a hard bid, or detailed estimate scenario. The research team used the Deseret Towers housing project at Brigham Young University as the basis for the research. A building information …
Modeling And Testing Of Dna Motion For Nanoinjection, Regis Agenor David
Modeling And Testing Of Dna Motion For Nanoinjection, Regis Agenor David
Theses and Dissertations
A new technique, called nanoinjection, is being developed to insert foreign DNA into a living cell. Such DNA transfection is commonly used to create transgenic organisms vital to the study of genetics, immunology, and many other biological sciences. In nanoinjection, DNA, which has a net negative charge, is electrically attracted to a micromachined lance. The lance then pierces the cell membranes, and the voltage on the lance is reversed, repelling the DNA into the cell. It is shown that DNA motion is strongly correlated to ion transport through a process called electrophoresis. Gel electrophoresis is used to move DNA using …
Hydraulic Conductivity Of Cement-Treated Soils And Aggregates After Freezing, Michael Scott Shea
Hydraulic Conductivity Of Cement-Treated Soils And Aggregates After Freezing, Michael Scott Shea
Theses and Dissertations
Improvements in the strength and durability of frost-susceptible soils and aggregates can be achieved through chemical stabilization using portland cement, where the efficacy of cement stabilization for improving durability depends on the degree to which hydraulic conductivity is reduced. Hydraulic conductivity is commonly estimated from basic soil properties using Moulton's empirical equation. However, the hydraulic conductivity estimation does not consider the detrimental effects of freezing or the benefits of cement stabilization. The purpose of this research was to derive new equations relating hydraulic conductivity after freezing to specific material properties of cement-treated soils and aggregates stabilized with different concentrations of …
Moving Ground Target Tracking In Urban Terrain Using Air/Ground Vehicles, Timothy Mclain, Randal W. Beard, Mark Owen, Huili Yu
Moving Ground Target Tracking In Urban Terrain Using Air/Ground Vehicles, Timothy Mclain, Randal W. Beard, Mark Owen, Huili Yu
Faculty Publications
In this paper, we present a framework for tracking a moving target in urban environments using UAVs in cooperation with UGVs. The framework takes into account occlusions between the sensor and the target. The target state is modeled using the dynamic occupancy grid and the target motion model is built using a second-order Markov chain. Based on the target occupancy grid, we design the path planning algorithm to maneuver the UAV and the UGV to configurations where they can detect the target with high probability. Simulation results show the framework is successful in solving the target tracking problem in urban …
Identifying Potential Applications For Lamina Emergent Mechanisms And Evaluating Their Suitability For Credit-Card-Sized Products, Nathan Bryce Albrechtsen
Identifying Potential Applications For Lamina Emergent Mechanisms And Evaluating Their Suitability For Credit-Card-Sized Products, Nathan Bryce Albrechtsen
Theses and Dissertations
Lamina emergent mechanisms (LEMs) are a maturing technology that is prepared for commercial implementation into new products. LEMs are defined by three functional characteristics; they (1) are compliant, (2) are fabricated from planar materials, and (3) emerge from a flat initial state. Advantages, design challenges, and design tools are described for each of the functional characteristics. Opportunities for LEMs are discussed, namely disposable LEMs, novel arrays of LEMs, scaled LEMs, LEMs with surprising motion, shock absorbing LEMs, and deployable LEMs. Technology push product development processes were employed to select applications for LEMs. LEM technology was characterized. In a LEM workshop, …
Automated Tool Design For Complex Free-Form Components, Kevin G. Foster
Automated Tool Design For Complex Free-Form Components, Kevin G. Foster
Theses and Dissertations
In today's competitive manufacturing industries, companies strive to reduce manufacturing development costs and lead times in hopes of reducing costs and capturing more market share from early release of their new or redesigned products. Tooling lead time constraints are some of the more significant challenges facing product development of advanced free-form components. This is especially true for complex designs in which large dies, molds or other large forming tools are required. The lead time for tooling, in general, consists of three main components; material acquisition, tool design and engineering, and tool manufacturing. Lead times for material acquisition and tool manufacture …
Minimizing Base Column Demands In Multi-Story Buckling Restrained Braced Frames Using Genetic Algorithms, Christopher Hiroshi Yeates
Minimizing Base Column Demands In Multi-Story Buckling Restrained Braced Frames Using Genetic Algorithms, Christopher Hiroshi Yeates
Theses and Dissertations
Most structural optimization procedures focus on minimizing the total volume of steel in an attempt to reduce overall costs. However, many other factors can have an effect on the overall cost of a structure. Base column demands in particular, can affect base plate sizes, anchorage, and foundation design. Researchers have found that present methods for estimating column demands are too conservative. Nonlinear time history analyzes were conducted on buckling-restrained braced frames of six heights. Optimized results were found considering three ductility constraints and two optimization objectives. The two optimization objectives were minimized total brace area and minimized base column demands. …
A Flexible Context Architecture For A Multi-User Gui, Yue Xu
A Flexible Context Architecture For A Multi-User Gui, Yue Xu
Theses and Dissertations
This thesis focuses on the design and development of a flexible context architecture for a multi-user GUI that serves several users engaged in collaborative computer-aided applications (CAx). The objective of this thesis is to extend previous research into multi-user GUI's by providing multiple users with a flexible context interface for interaction with other users working on the same part at distributed locations. The investigation will consider how distributed users, through user interfaces, interact to simultaneously build models and how interaction context might be presented to regulate the way they wish to interact. The implementation integrates a Multi-User GUI (MUG) with …
Liquefaction Mitigation In Silty Sands At Salmon Lake Dam Using Stone Columns And Wick Drains, Emily Dibb Thiriot
Liquefaction Mitigation In Silty Sands At Salmon Lake Dam Using Stone Columns And Wick Drains, Emily Dibb Thiriot
Theses and Dissertations
Stone columns are an established method of liquefaction mitigation in clean sands (fines content <15%). Although stone columns are considered less effective in silty soils, an increase in the area replacement ratio or the addition of wick drains may still produce improvement in the normalized blow count. Limited case histories are available with a direct comparison of the use of stone columns with and without wick drains at one location. The Salmon Lake Dam Modification project provided such a scenario. Two test sections were completed at the site prior to construction to determine the area replacement ratio for the final design as well as to compare the application of stone columns with and without wick drains. Visual observations of water and air escaping from wick drains within a distance of 15 ft of the stone column construction confirmed that drains aided in pore pressure dissipation. Test results indicated that stone column treatment with wick drains produced greater improvement in blow count than stone column treatment without drains. For the overall site, there was an increase in improvement ranging from 3 to 8 SPT blow counts. When compared to the results of a similar evaluation of a site in Ogden, Utah, which had a comparable fines content and an area replacement ratio of 26%, the increase in stone column effectiveness produced by adding wick drains was lower at the Salmon Lake Dam site. The increase in improvement at the Ogden, Utah site ranged from 12 to 18 SPT blow counts. At the Ogden site, wick drains were placed between every stone column while they were only placed between vertical rows of columns at Salmon Lake dam. Despite the beneficial effects provided by using wick drains with stone column treatment in silty soils, the performance was below what would be expected for stone column treatment without wick drains in clean sands with less than 15% fines. Stone column treatment also proved less effective in layers of sandy silt than in layers of silty sand, which was indicated by lower average improvement and more points of negative improvement in layers of sandy silt. Although several different area replacement ratios were analyzed (23, 27, 31, and 35%), no consistent trend towards greater improvement in blow count was seen as the replacement ratio increased beyond 23%.
Investigation Of Mechanical Differentials As Continuously Variable Transmissions, Dax B. Wells
Investigation Of Mechanical Differentials As Continuously Variable Transmissions, Dax B. Wells
Theses and Dissertations
In recent years the increasing demand for fuel efficient and less pollutant vehicles has stimulated the development of hybrid and electric vehicles. These vehicle platforms often incorporate drivetrains which utilize multiple power sources for vehicle propulsion in an effort to increase fuel mileage and reduce emissions. Coupling multiple power sources, such as an internal combustion engine and electric motor(s), has new challenges in drivetrain design. Understanding the torque and rpm relationships within the power transmission device used to combine power sources is fundamental to overcoming the design challenges associated with hybrid and electric vehicle platforms. Results from this research include …
Lean Manufacturing As A Source Of Competitive Advantage, Ryan Scott Williams
Lean Manufacturing As A Source Of Competitive Advantage, Ryan Scott Williams
Theses and Dissertations
The productivity advances generated from lean manufacturing are self-evident. Plants that adopt lean are more capable of achieving high levels of quality, shorter lead times, and less waste in the system. While it seems logical that higher levels of productivity and quality, as is common in lean companies, should result in positive financial performance, the research community has failed to establish the financial profitability of lean. Those researchers who have studied the financial returns issue report varying results. The goal of this research was to determine if a connection exists between lean and financial success and to discover why so …
Improved Measurement And Separation Techniques For Interior Near-Field Acoustical Holography, Zachary A. Collins
Improved Measurement And Separation Techniques For Interior Near-Field Acoustical Holography, Zachary A. Collins
Theses and Dissertations
Recent advances in near-field acoustical holography (NAH) have expanded the theory to interior spaces where multiple sources and/or reflections are present. In 1990, Tamura presented the spatial Fourier transform separation method to measure the reflection coefficient at oblique angles using two measurement planes in the wave number domain. This paper adapts the spatial Fourier transform separation method for application in interior NAH. A practical exploration of important experimental parameters is performed, which include the relative amplitudes of primary and disturbing sources, the measurement plane separation distance, and an acceptable noise floor. This technique is successfully applied in a reverberant environment …
Straightness Of Growth For Carbon Nanotube Microelectromechanical Systems, Kellen S. Moulton
Straightness Of Growth For Carbon Nanotube Microelectromechanical Systems, Kellen S. Moulton
Theses and Dissertations
The purpose of this research is to examine the effect of iron catalyst thickness on the straightness of growth of carbon nanotube microelectromechanical systems (CNT-MEMS). One of the key benefits of CNT-MEMS is that they can potentially have very high aspect ratios. One of the challenges in attaining these high aspect ratios is maintaining device straightness; as these devices get taller, the edges tend to curve rather than grow straight vertically. Scanning electron mi- croscope images of samples grown using various iron catalyst thicknesses show that both straight growth and relatively good edge definition can be achieved using iron thicknesses …
Understanding The Economics Of Transportation In Utah, Jeremy E. Searle
Understanding The Economics Of Transportation In Utah, Jeremy E. Searle
Theses and Dissertations
Understanding the economic impacts of transportation projects in Utah is essential for decision makers, officials, and stakeholders as they determine the best course of action for the state. Economic impacts can guide decisions of future projects and help explain past economic fluctuations. This study develops a process that can be used to identify the economic impacts of transportation projects in Utah and quantify the relationship between transportation and these impacts. Accomplishing the objectives of this study are a product of: 1) performing a comprehensive literature review, 2) collecting data and establishing analysis methods, 3) completing a statistical analysis and breakdown …
An Onboard Vision System For Unmanned Aerial Vehicle Guidance, Barrett Bruce Edwards
An Onboard Vision System For Unmanned Aerial Vehicle Guidance, Barrett Bruce Edwards
Theses and Dissertations
The viability of small Unmanned Aerial Vehicles (UAVs) as a stable platform for specific application use has been significantly advanced in recent years. Initial focus of lightweight UAV development was to create a craft capable of stable and controllable flight. This is largely a solved problem. Currently, the field has progressed to the point that unmanned aircraft can be carried in a backpack, launched by hand, weigh only a few pounds and be capable of navigating through unrestricted airspace. The most basic use of a UAV is to visually observe the environment and use that information to influence decision making. …
Nonlinear Observability Analysis Of Bearing-Only Cooperative Localization Using Graph Theory, Rajnikant Sharma
Nonlinear Observability Analysis Of Bearing-Only Cooperative Localization Using Graph Theory, Rajnikant Sharma
Faculty Publications
In this report we investigate the nonlinear observability properties of bearing-only cooperative localization. We establish a link between observability and a graph representing measurements and communication between the robots.
Observability Analysis Of Bearing-Only Cooperative Localization, Rajnikant Sharma
Observability Analysis Of Bearing-Only Cooperative Localization, Rajnikant Sharma
Faculty Publications
In this report we investigate the nonlinear observability properties of bearing-only cooperative localization. We establish a link between observability and a graph representing measurements and communication between the robots. It is shown that graph theoretic properties like the connectivity and the existence of a path between two nodes can be used to explain the observability of the system.
Effectiveness Of Compacted Fill And Rammed Aggregate Piers For Increasing Lateral Resistance Of Pile Foundations, Nathan A. Lemme
Effectiveness Of Compacted Fill And Rammed Aggregate Piers For Increasing Lateral Resistance Of Pile Foundations, Nathan A. Lemme
Theses and Dissertations
Compacted fill and rammed aggregate piers (RAPs) were separately installed adjacent to a 9-ft by 9-ft by 2.5-ft driven pile foundation founded in soft clay. The compacted fill used to laterally reinforce an area of 11 ft by 5 ft by 6 ft deep adjacent to the pile cap was clean concrete sand. The thirty-inch diameter RAPs were installed in three staggered rows to a depth of 12.5 ft below the ground surface adjacent to the pile cap to test the increase in lateral resistance afforded by their installation. The foundation was laterally loaded and load, displacement, and strain readings …
Mimo Channel Spatial Covariance Estimation: Analysis Using A Closed-Form Model, Yanling Yang
Mimo Channel Spatial Covariance Estimation: Analysis Using A Closed-Form Model, Yanling Yang
Theses and Dissertations
Multiple-input Multiple-output (MIMO) wireless communication systems allow increased spectral efficiency and therefore promise significant improvement in performance. However, because of the rapid variation in channel state information (CSI) in networks with mobile nodes or scatterers, it is difficult both to maintain high communication performance and to create channel models that effectively represent the time-varying behavior of the channels. The spatial covariance of the MIMO channel describes the average power gain on each transmit-receive antenna pair as well as the correlation between the complex link gains and thus provides critical information for understanding the performance of the system and for creating …
Design Principles And Preliminary Actuation Approaches For Novel Multiple-Layer Lamina Emergent Mechanisms, Paul Shumway Gollnick
Design Principles And Preliminary Actuation Approaches For Novel Multiple-Layer Lamina Emergent Mechanisms, Paul Shumway Gollnick
Theses and Dissertations
Multiple-layer Lamina Emergent Mechanisms (MLEMs) are mechanisms made from multiple sheets (lamina) of material with motion that emerges out of the fabrication plane. This study has shown that understanding how layers are used in existing products and in nature provides insight into how MLEMs can also use layers to achieve certain tasks. The multi-layered nature of MLEMs and the interactions between these layers are what enhance the capabilities of MLEMs and allow them to better meet design objectives. Layer separation is one objective for which MLEMs are well-suited. Layer separation can have a variety of applications and there are a …
Search Pattern Generation And Path Management For Search Over Rough Terrain With A Small Uav, Jacob L. Bishop
Search Pattern Generation And Path Management For Search Over Rough Terrain With A Small Uav, Jacob L. Bishop
Theses and Dissertations
Search operations can be described by the interaction between three entities: the target, the sensor, and the environment. Past treatments of the search problem have focused primarily on the interaction between the sensor and the target. The effects that the environment has on the target and sensor have been greatly simplified or ignored completely. The wilderness search and rescue scenario is one case in which these interactions cannot be safely ignored. Using the wilderness search and rescue problem as our motivating example, we develop an algorithm for planning search paths for a small unmanned aerial vehicle (UAV) over rough terrain …
Effects Of Thermal Gradient And Fines Content On Frost Heave Of An Alaska Base Material, Adam Ray Homewood
Effects Of Thermal Gradient And Fines Content On Frost Heave Of An Alaska Base Material, Adam Ray Homewood
Theses and Dissertations
The objective of this research was to investigate the effects of thermal gradient and fines content and the interaction between these two factors on the frost heave characteristics of a typical Alaska base material. The laboratory frost heave testing involved one type of aggregate base material, three thermal gradients, and three fines contents in a full-factorial experimental design with two replicates. The aggregate was classified in the American Association of State Highway and Transportation Officials soil classification system as A-1-a; the thermal gradients were 0.15, 0.30, and 0.45 ºC/cm; and the fines contents were 6, 8, and 10 percent. After …
Scatterometer Contamination Mitigation, Michael Paul Owen
Scatterometer Contamination Mitigation, Michael Paul Owen
Theses and Dissertations
Microwave scatterometers, which use radar backscatter measurements to infer the near-surface wind vector, are unique in their ability to monitor global wind vectors at high resolutions. However, scatterometer observations which are contaminated by land proximity or rain events produce wind estimates which have increased bias and variability, making them unreliable for many applications. Fortunately, the effects of these sources of contamination can be mitigated. Land contamination of backscatter measurements occurs when land partially fills the antenna illumination area. This reduces and masks the wind-induced backscatter signal. Land contamination is mitigated by quantifying the amount of contamination in a single observation …
Qpsk And Oqpsk In Frequency Nonselective Fading, Michael D. Rice
Qpsk And Oqpsk In Frequency Nonselective Fading, Michael D. Rice
Faculty Publications
The maximum likelihood estimator for the fading gain in a frequency non-selective fading channel is derived and analyzed for offset QPSK (OQPSK). The corresponding impact of estimator errors on the bit error probability performance for OQPSK is also derived.
Developing Intelligent Engineering Collaboration Tools Through The Use Of Design Rationale, Jordan David Ryskamp
Developing Intelligent Engineering Collaboration Tools Through The Use Of Design Rationale, Jordan David Ryskamp
Theses and Dissertations
This thesis presents a new method that improves upon the existing approaches to developing collaborative tools. The new method uses automatically inferred and manually recorded design rationale to intelligently filter the information that is shared by a collaborative tool. This represents an improvement upon the existing state of the art in collaborative engineering tools. To demonstrate the viability of the method three collaborative tools were created. The first is a multi-user collaborative design environment tool named SimulPart and built upon the NX CAD package. SimulPart uses the new method to limit the amount of communication required to keep every user …
Analysis Of Construction-Related Research Compared To Needs Of Industry Professionals, Sterling Graham
Analysis Of Construction-Related Research Compared To Needs Of Industry Professionals, Sterling Graham
Theses and Dissertations
Research plays a large role in the advancement of any industry. It is particularly important that relevant research is performed in an industry as large and critical as the construction industry. A review of literature shows that historically research has not played a major role in the advancement of the construction industry. The work of this thesis was to explore whether there has been a change in this relationship, or not. This thesis explored whether the construction-related research being done is in alignment with the needs of industry. Comparisons of the rankings of construction research and industry views were done …