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Articles 121 - 138 of 138
Full-Text Articles in Engineering
Lateral Resistance Of Piles Near Vertical Mse Abutment Walls At Provo Center Street, Kent R. Nelson
Lateral Resistance Of Piles Near Vertical Mse Abutment Walls At Provo Center Street, Kent R. Nelson
Theses and Dissertations
Full scale lateral load tests were performed on four piles located at various distances behind MSE walls. Three of the four test piles were production piles used to support bridges, and the other pile a production pile used as part of the bridge abutment. The objective of the testing was to determine the effect of spacing from the wall on the lateral resistance of the piles and on the force resisted by the MSE reinforcement. Lateral load-displacement curves were developed for pile at various spacing and with various reinforcement ratio (reinforcement length, L divided by wall height, H). The force …
Starch Resin Moisture Level Effect On Injection Molding Processability And Molded Part Mechanical Properties With Pure Starch Resin And Polymer Blends, Jordan M. Ellingson
Starch Resin Moisture Level Effect On Injection Molding Processability And Molded Part Mechanical Properties With Pure Starch Resin And Polymer Blends, Jordan M. Ellingson
Theses and Dissertations
The current and forecasted global consumption of plastic packaging and products through the 21st century combined with the already reported and growing negative impact of plastics on the environment due to plastics being synthesized from nonrenewable resources that do not biodegrade is of serious concern. However, recent advances in starch technology including the development of thermoplastic starch (TPS) materials —polymers that are both renewable and biodegradable—have brought hope to reducing this impact. The mechanical properties of thermoplastic starch have often been improved by blending with synthetic polymers. One issue that arises with blending is volatilization of the melt from moisture …
Location-Allocation Optimization Of Supply Chain Distribution Networks: A Case Study, Mark Nicholas Helberg
Location-Allocation Optimization Of Supply Chain Distribution Networks: A Case Study, Mark Nicholas Helberg
Theses and Dissertations
The location of distribution centers is an important strategic decision in supply chain design, particularly as it relates to service quality, productivity, and profitability of the firm. There has been extensive research performed on distribution location models which require the use of complex algorithms and assumptions that make use of these models difficult in practice for small and medium enterprises (SMEs) that have limited capital and resources. Studies have also failed to capture and quantify potential business results of using more sophisticated methods. In this study, a deterministic and static location-allocation model is designed using a prototype software tool. The …
Entropic Depletion Of Dna In Triangular Nanochannels, Wesley F. Reinhart, Douglas R. Tree, Kevin D. Dorfman
Entropic Depletion Of Dna In Triangular Nanochannels, Wesley F. Reinhart, Douglas R. Tree, Kevin D. Dorfman
Faculty Publications
Using Monte Carlo simulations of a touching-bead model of double-stranded DNA, we show that DNA extension is enhanced in isosceles triangular nanochannels (relative to a circular nanochannel of the same effective size) due to entropic depletion in the channel corners. The extent of the enhanced extension depends non-monotonically on both the accessible area of the nanochannel and the apex angle of the triangle. We also develop a metric to quantify the extent of entropic depletion, thereby collapsing the extension data for circular, square, and various triangular nanochannels onto a single master curve for channel sizes in the transition between the …
A Steady-State Detection (Ssd) Algorithm To Detect Non-Stationary Drifts In Processes, Jeff Kelly, John Hedengren
A Steady-State Detection (Ssd) Algorithm To Detect Non-Stationary Drifts In Processes, Jeff Kelly, John Hedengren
Faculty Publications
Detecting windows or intervals of when a continuous process is operating in a state of steadiness is useful especially when steady-state models are being used to optimize the process or plant on-line or in real-time. The term steady-state implies that the process is operating around some stable point or within some stationary region where it must be assumed that the accumulation or rate-of-change of material, energy and momentum is statistically insignificant or negligible. This new approach is to assume the null-hypothesis that the process is stationary about its mean subject to independent and identically distributed random error or shocks (white-noise) …
Quantifying The Nonlinear, Anisotropic Material Response Of Spinal Ligaments, Daniel J. Robertson
Quantifying The Nonlinear, Anisotropic Material Response Of Spinal Ligaments, Daniel J. Robertson
Theses and Dissertations
Spinal ligaments may be a significant source of chronic back pain, yet they are often disregarded by the clinical community due to a lack of information with regards to their material response, and innervation characteristics. The purpose of this dissertation was to characterize the material response of spinal ligaments and to review their innervation characteristics.
Review of relevant literature revealed that all of the major spinal ligaments are innervated. They cause painful sensations when irritated and provide reflexive control of the deep spinal musculature. As such, including the neurologic implications of iatrogenic ligament damage in the evaluation of surgical procedures …
Covariance Modeling And Space-Time Coding For Mimo Systems, Farnaz Karimdady Sharifabad
Covariance Modeling And Space-Time Coding For Mimo Systems, Farnaz Karimdady Sharifabad
Theses and Dissertations
The full spatial covariance matrix of the multiple input multiple-output (MIMO) channel is an important quantity in channel modeling, communication system signal processing, and performance analysis, and therefore this matrix forms the heart of the research outlined in this dissertation. The work begins with an investigation of a generalized framework for computing the full MIMO spatial covariance based on the power angular spectrum (PAS) of the multipath field and the transmit and receive antenna element radiation patterns. For the case of uniform linear arrays and when the PAS clusters satisfy uniform, truncated Gaussian, or truncated Laplacian distributions, a series expansion …
Directional Electric Field Sensing Using Slab Coupled Optical Fiber Sensors, Daniel Theodore Perry
Directional Electric Field Sensing Using Slab Coupled Optical Fiber Sensors, Daniel Theodore Perry
Theses and Dissertations
This thesis provides the details of a multi-axis electric field sensor. The sensing element consists of three slab coupled optical fiber sensors that are combined to allow directional electric field sensing. The packaged three-axis sensor has a small cross-sectional area of 0.5 cm x 0.5 cm achieved by using an x-cut crystal. The method is described that uses a sensitivity-matrix approach to map the measurements to field components. The calibration and testing are described resulting in an average error of 1.5º.This work also includes a description of the packaging method used as well as a thorough analysis of the directional …
Objectives And Constraints For Wind Turbine Optimization, Andrew Ning, Rick Damiani, Patrick Moriarty
Objectives And Constraints For Wind Turbine Optimization, Andrew Ning, Rick Damiani, Patrick Moriarty
Faculty Publications
Efficient extraction of wind energy is a complex multidisciplinary process. This paper examines common objectives used in wind turbine optimization problems. The focus is not on the specific optimized designs, but rather on understanding when certain objectives and constraints are necessary, and what their limitations are. Maximizing annual energy production, or even using sequential aero/structural optimization, is shown to be significantly suboptimal compared to integrated aero/structural metrics. Minimizing the ratio of turbine mass to annual energy production can be effective for fixed rotor diameter designs, as long as the tower mass is estimated carefully. For variable diameter designs, the predicted …
Supercritical Co2 Brayton Cycles For Solar-Thermal Energy, Brian D. Iverson, Thomas M. Conboy, James J. Pasch, Alan M. Kruizenga
Supercritical Co2 Brayton Cycles For Solar-Thermal Energy, Brian D. Iverson, Thomas M. Conboy, James J. Pasch, Alan M. Kruizenga
Faculty Publications
Of the mechanisms to improve efficiency for solar-‐thermal power plants, one of the most effective ways to improve overall efficiency is through power cycle improvements. As increases in operating temperature continue to be pursued, supercritical CO2 Brayton cycles begin to look more attractive despite the development costs of this technology. Further, supercritical CO2 Brayton has application in many areas of power generation beyond that for solar energy alone.
One challenge particular to solar-‐thermal power generation is the transient nature of the solar resource. This work illustrates the behavior of developmental Brayton turbomachinery in response to a fluctuating thermal input, much …
Characterization Of Macromolecular Structure Of Pyrolysis Products From A Colorado Green River Oil Shale, James L. Hillier, Thomas H. Fletcher, Mark S. Solum, Ronald J. Pugmire
Characterization Of Macromolecular Structure Of Pyrolysis Products From A Colorado Green River Oil Shale, James L. Hillier, Thomas H. Fletcher, Mark S. Solum, Ronald J. Pugmire
Faculty Publications
Volatile products from an oil shale from the Colorado Green River formation were studied by several methods. The oil shale was demineralized, and the resulting kerogen was also chemically analyzed. Both the oil shale and the demineralized kerogen were pyrolyzed at 10 K/min, and the pyrolysis products (light gas, tar, and char) were analyzed using 13C NMR, XPS, GC/MS, and FTIR. Low temperature ashing was performed in order to compare pyrolysis yields of oil shale and demineralized kerogen on a dry ash-free basis. Volatile yields of approximately 75% were achieved in an oil shale retort and 79% in the kerogen …
Analysis Of Integrated Engineering And Social Science Approaches For Projects In Developing Communities, Parry F. Garff, Eric C. Dahlin, Carol Ward, Randy Lewis
Analysis Of Integrated Engineering And Social Science Approaches For Projects In Developing Communities, Parry F. Garff, Eric C. Dahlin, Carol Ward, Randy Lewis
Faculty Publications
Current design methods such as appropriate technology, human-centered design, and participatory design are intended to generate development projects that resonate with users in communities in developing countries. These approaches are extremely useful, but often lack adequate documentation about how to collect data on and incorporate users feedback into the project’s design. To address this gap, we introduced social science research methods into a service-learning course for undergraduate engineering students, which culminated in a trip to the communities for whom they were designing, to help students incorporate user feedback into the design of their projects. This paper documents our efforts. One …
Electrochemical Explanation For Asymmetric Electrowetting Response, Mehdi Khodayari, Nathan B. Crane, Alex A. Volinsky
Electrochemical Explanation For Asymmetric Electrowetting Response, Mehdi Khodayari, Nathan B. Crane, Alex A. Volinsky
Faculty Publications
In electrowetting, a droplet/substrate contact angle is modulated by applying a potential difference between the droplet and the substrate. Typically, the droplet potential is changed via an auxiliary electrode dipped in the droplet. Here, it is shown that electrochemical reactions lead to a potential drop on the auxiliary electrode in electrowetting, which degrades the droplet contact angle modulation. The magnitude of this effect depends on the voltage polarity. This problem can be addressed by using a dielectric layer, such as SiO2, which can prevent electrochemical reactions with the electrowetting substrate and the auxiliary electrode.
Final Report: Multipath Modeling And Mitigation Using Multiple Antennas (M4a), Michael Rice
Final Report: Multipath Modeling And Mitigation Using Multiple Antennas (M4a), Michael Rice
Faculty Publications
This report documents the effort under contract W900KK-09-C-0016. The contract comprised four phases spanning 15 April 2009 to 1 December 2012. The relationship between the effort associated with each phase and the contents of this report are as follows: Phase 1 was devoted exclusively to the channel sounding experiments with the UH-1H helicopter. The experimental setup, procedure, and results for the channel sounding experiments at Cairns Army Airfield and Patuxent River are described in Chapter 2. Good, usable data at upper L-band was captured during the Cairns Army Airfield experiments. Phase 2 was devoted to the channel sounding experiments with …
Time-Dependent Deposition Characteristics Of Fine Coal Fly Ash In A Laboratory Gas Turbine Environment, Robert Laycock, Thomas H. Fletcher
Time-Dependent Deposition Characteristics Of Fine Coal Fly Ash In A Laboratory Gas Turbine Environment, Robert Laycock, Thomas H. Fletcher
Faculty Publications
Time-dependent deposition characteristics of fine coal fly ash were measured in the Turbine Accelerated Deposition Facility (TADF) at Brigham Young University. Two samples of subbituminous coal fly ash, with mass mean diameters of 3 and 13 microns, were entrained in a hot gas flow with a gas temperature of 1288 C and Mach number of 0.25. A nickel-based, superalloy metal coupon approximately 0.3 cm thick was held in a hot particle-laden gas stream to simulate deposition in a gas turbine. Tests were conducted with deposition times of 20, 40, and 60 min. Capture efficiencies and surface roughness characteristics (e.g., Ra) …
Coal Char-Co2 Gasification Measurements And Modeling In A Pressurized Flat-Flame Burner, Randy C. Shurtz, Thomas H. Fletcher
Coal Char-Co2 Gasification Measurements And Modeling In A Pressurized Flat-Flame Burner, Randy C. Shurtz, Thomas H. Fletcher
Faculty Publications
A pressurized flat-flame burner (PFFB) was used to conduct coal gasification studies. The PFFB was designed to provide an environment with laminar, dispersed entrained flow, with particle heating rates of ∼105 K/s, pressures of up to 15 atm, and gas temperatures of up to 2000 K. Residence times were varied from 30 to 700 ms in this study. Char gasification studies by CO2 were conducted on a subbituminous coal and 4 bituminous coals in the PFFB. Pressures of 5, 10, and 15 atm were used with gas compositions of 20, 40, and 90 mol % CO2. Gas conditions with peak …
Prediction Of Sawdust Pyrolysis Yields From A Flat-Flame Burner Using The Cpd Model, Aaron D. Lewis, Thomas H. Fletcher
Prediction Of Sawdust Pyrolysis Yields From A Flat-Flame Burner Using The Cpd Model, Aaron D. Lewis, Thomas H. Fletcher
Faculty Publications
High heating rate pyrolysis experiments were performed on a softwood sawdust in a flat-flame burner reactor at temperatures from 1163 to 1433 K with particle residence times ranging from 23 to 102 ms at atmospheric pressure. Volatile yields of the 45−75 μm sawdust were measured and are believed to be similar to those that would occur in an industrial entrained-flow combustor or gasifier. A refractory tar yield near 1.5 wt % (dry, ash-free) was measured. A high percentage of the fully pyrolyzed sawdust char was spherical, having lost the original sawdust structure. It is suggested that the morphology of sawdust …
Techno- Economic Analysis Of Wastewater Biosolids Gasification, Jason M. Porter, Nick Lumley, Robert Braun, Tzahi Cath, Ana Prietro, Dotti Ramey, Greta Buschmann
Techno- Economic Analysis Of Wastewater Biosolids Gasification, Jason M. Porter, Nick Lumley, Robert Braun, Tzahi Cath, Ana Prietro, Dotti Ramey, Greta Buschmann
Faculty Publications
Wastewater treatment biosolids, commonly referred to as sludge, is a dilute suspension of micro-organisms, noxious organic matter, and mineral species in up to 99% water. Sludge is produced at about 250 mg/L of mixed municipal and light industrial wastewater treated. Management of this process stream can present a financial and environmental challenge for wastewater treatment plants (WWTPs), accounting for up to 15% of plant energy consumption. Operators of small urban WWTPs see the greatest challenge as their operations do not benefit from economies of scale, which permit larger facilities to absorb the costs or footprint of anaerobic digestion. This work …