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Articles 1 - 20 of 20
Full-Text Articles in Engineering
Beyond Gel Electrophoresis: Microfluidic Separations, Fluorescence Burst Analysis, And Dna Stretching, Kevin D. Dorfman, Scott B. King, Daniel W. Olson, Joel D. P. Thomas, Douglas R. Tree
Beyond Gel Electrophoresis: Microfluidic Separations, Fluorescence Burst Analysis, And Dna Stretching, Kevin D. Dorfman, Scott B. King, Daniel W. Olson, Joel D. P. Thomas, Douglas R. Tree
Faculty Publications
This review addresses methods for obtaining sequence information directly from unamplified genomic length DNA. Our generic starting point is a large piece of DNA that contains many thousands of base pairs (kilobase pairs, kbp) or even millions of base pairs (megabase pairs, Mbp). We would like to determine the genomic distance between two repeats of a given sequence, indicated by the red dots on the coiled DNA molecule in Figure 1. Let us consider the case where these sequences are restriction sites, which can be selectively cut using proteins known as restriction enzymes. For decades, gel electrophoresis served as the …
Thermal And Mechanical Properties Of Nitrate Thermal Storage Salts In The Solid-Phase, Brian D. Iverson, Scott T. Broome, Alan M. Kruizenga, Joseph G. Cordaro
Thermal And Mechanical Properties Of Nitrate Thermal Storage Salts In The Solid-Phase, Brian D. Iverson, Scott T. Broome, Alan M. Kruizenga, Joseph G. Cordaro
Faculty Publications
Implementation of molten salt compounds as the heat transfer fluid and energy storage medium provides specific benefits to energy collection and conversion. Nitrate salts have been identified as a strong candidate for energy transfer and storage and have been demonstrated for use in these applications over time. As nitrate salts have solidification temperatures above ambient, concern for recovery from salt freezing events has instigated efforts to understand and predict this behavior. Accurate information of salt property behavior in the solid-phase is necessary for understanding recovery from a freeze event as well as for phase change thermal energy storage applications. Thermal …
Spherical Lamina Emergent Mechanisms, Samuel E. Wilding, Larry L. Howell, Spencer P. Magleby
Spherical Lamina Emergent Mechanisms, Samuel E. Wilding, Larry L. Howell, Spencer P. Magleby
Faculty Publications
Lamina emergent mechanisms (LEMs) are compliant mechanisms that can be manufactured from planar materials and are capable of motion out of the plane of manufacture. Spherical LEMs combine the unique motion of spherical mechanisms with the compactness and simple topology of LEMs. The fundamentals of spherical LEMs are discussed in this work. It is found that 21 of the 33 possible spherical 4R types can be spherical LEMs. A classification based on these 21 possible types is developed. This classification is used to predict motion capabilities of spherical 6R, and Equintet mechanisms. It is also applied to arrays of spherical …
Introduction Of Planar Compliant Joints Designed For Combined Bending And Axial Loading Conditions In Lamina Emergent Mechanisms, Samuel E. Wilding, Larry L. Howell, Spencer P. Magleby
Introduction Of Planar Compliant Joints Designed For Combined Bending And Axial Loading Conditions In Lamina Emergent Mechanisms, Samuel E. Wilding, Larry L. Howell, Spencer P. Magleby
Faculty Publications
This work introduces three joints to allow motion in lamina emergent mechanisms (LEMs) that were designed to have minimal parasitic motion under tension, compression, and a combination of tension and compression loading. Closed-form models of the joints were developed and combined with optimization algorithms for maximum flexibility in bending and then modeled using finite element analysis (FEA). The FEA results were used to predict the stiffness of the joints in bending, tension, and compression. As a baseline, lamina emergent torsional (LET) joints were designed to match the bending stiffness of each of the joints, so that the tensile-compressive performance could …
Technical Note On Manipulating Multivariate Gaussian Distributions, John C. Macdonald
Technical Note On Manipulating Multivariate Gaussian Distributions, John C. Macdonald
Student Works
In this technical note we present some derivations treating conditional, marginal, and joint distributions for Gaussian random vectors.
Constrained Control And Optimization Of Tubular Solid Oxide Fuel Cells For Extending Cell Lifetime, Ben Spivey, John Hedengren, Thomas F. Edgar
Constrained Control And Optimization Of Tubular Solid Oxide Fuel Cells For Extending Cell Lifetime, Ben Spivey, John Hedengren, Thomas F. Edgar
Faculty Publications
Extending fuel cell lifetime is a necessary objective for reducing fuel cell power generation cost of electricity. Capital costs comprise the most significant fraction of the cost of electricity. Reducing the frequency of fuel cell replacement can be achieved by implementing a control strategy that prevents excursions into operating regions causing failure. In this paper we implement a constrained MIMO model predictive controller (MPC) to avoid the failure modes relevant for a high-temperature tubular solid oxide fuel cell (SOFC) system while performing load-following. The primary causes of failure are catalyst poisoning, fuel or air starvation, carbon deposition, and microcracking. Prior …
Fiber Optic Monitoring Of Subsea Equipment, David Brower, John Hedengren, Cory Loegering, Alexis Brower, Karl Witherow, Karl Winter
Fiber Optic Monitoring Of Subsea Equipment, David Brower, John Hedengren, Cory Loegering, Alexis Brower, Karl Witherow, Karl Winter
Faculty Publications
Bass Lite deepwater field in the Gulf of Mexico, at water depths of approximately 2,050 m (6,750 feet), commenced operation in February 2008. Natural gas is produced from Bass Lite via a 90-km (56-mile) subsea tieback to the Devils Tower Spar. This project involved several innovations, one of which was the incorporation of a fiber optic sensing system that measures realtime temperature, pressure and strain along the pipeline length. This is a first of its kind innovation that is in actual operation.
Mobility Of A Semiflexible Chain Confined In A Nanochannel, Douglas R. Tree, Yanwei Wang, Kevin D. Dorfman
Mobility Of A Semiflexible Chain Confined In A Nanochannel, Douglas R. Tree, Yanwei Wang, Kevin D. Dorfman
Faculty Publications
The classic results of de Gennes and Odijk describe the mobility of a semiflexible chain confined in a nanochannel only in the limits of very weak and very strong confinement, respectively. Using Monte Carlo sampling of the Kirkwood diffusivity with full hydrodynamic interactions, we show that the mobility of a semiflexible chain exhibits a broad plateau as a function of extension before transitioning to an Odijk regime, and that the width of the plateau depends on the anisotropy of the monomers. For the particular case of DNA in a high ionic strength buffer, which has highly anisotropic monomers, we predict …
Relative Navigation And Control Of A Hexacopter, Timothy Mclain, Randal W. Beard, Robert C. Leishman, John Macdonald
Relative Navigation And Control Of A Hexacopter, Timothy Mclain, Randal W. Beard, Robert C. Leishman, John Macdonald
Faculty Publications
This paper discusses the progress made on developing a multi-rotor helicopter equipped with a vision-based ability to navigate through an a priori unknown, GPS-denied environment. We highlight the backbone of our system, the relative estimation and control. We depart from the common practice of using a globally referenced map, preferring instead to keep the position and yaw states in the EKF relative to the current map node. This relative navigation approach allows simple application of sensor updates, natural characterization of the transformation between map nodes, and the potential to generate a globally consistent map when desired. The EKF fuses view …
Chemical Potential Perturbation: Extension Of The Method To Lattice Sum Treatment Of Intermolecular Potentials, Stan G. Moore, Dean R. Wheeler
Chemical Potential Perturbation: Extension Of The Method To Lattice Sum Treatment Of Intermolecular Potentials, Stan G. Moore, Dean R. Wheeler
Faculty Publications
The recently developed chemical potential perturbation (CPP) method [S. G. Moore and D. R. Wheeler, J. Chem. Phys. 134, 114514 (2011) https://doi.org/10.1063/1.3561865.] is extended to the lattice (Ewald) sum treatment of intermolecular potentials. The CPP method predicts chemical potentials for a range of composition points using the local (position-dependent) pressure tensor of an inhomogeneous system. When computing the local pressure tensor, one can use the Irving-Kirkwood (IK) or Harasima (H) contours of distributing the pressure. We compare these two contours and show that for a planar interface, the homogeneous pressure and resulting chemical potential can be approximated with …
Aircraft Route Optimization For Heterogeneous Formation Flight, Jia Xu, Andrew Ning, Geoffrey Bower, Ilan Kroo
Aircraft Route Optimization For Heterogeneous Formation Flight, Jia Xu, Andrew Ning, Geoffrey Bower, Ilan Kroo
Faculty Publications
We examine the value of extended formation flight in the context of airline operations. The study is based on a bi-level route optimization framework. The aircraft performance model includes the effects of rolled-up wakes, formation heterogeneity, and formation-induced compressibility effects. We incorporate airline economics to understand the trade-off between speed and drag savings in the context of formation flight. The application of formation flight to a representative South African Airlines (SAA) long-haul route network can reduce fuel burn by over 4.6% or reduce direct operating cost by 2.1%. The savings increase to 6.8% in fuel or 2.4% in cost when …
Resolution Limit For Dna Barcodes In The Odijk Regime, Yanwei Wang, Wes F. Reinhart, Douglas R. Tree, Kevin D. Dorfman
Resolution Limit For Dna Barcodes In The Odijk Regime, Yanwei Wang, Wes F. Reinhart, Douglas R. Tree, Kevin D. Dorfman
Faculty Publications
We develop an approximation for the probability of optically resolving two fluorescent labels on the backbone of a DNA molecule confined in a nanochannel in the Odijk regime as a function of the fluorescence wavelength, channel size, and the properties of the DNA (persistence length and effective width). The theoretical predictions agree well with equivalent data produced by Monte Carlo simulations of a touching wormlike bead model of DNA in a high ionic strength buffer. Although the theory is only strictly valid in the limit where the effective width of the nanochannel is small compared with the persistence length of …
Deposition Near Film Cooling Holes On A High Pressure Turbine Vane, Weiguo Ai, Nathan Murray, Thomas H. Fletcher, Spencer Harding, Scott Lewis, Jeffrey P. Bons
Deposition Near Film Cooling Holes On A High Pressure Turbine Vane, Weiguo Ai, Nathan Murray, Thomas H. Fletcher, Spencer Harding, Scott Lewis, Jeffrey P. Bons
Faculty Publications
Deposition on film-cooled turbine components was studied in an accelerated test facility. The accelerated deposition facility seeds a natural-gas burning combustor with finely ground coal ash particulate at 1180 C and 180 m/s (M=0.25). Both cylindrical and shaped holes, with and without thermal barrier coating, were studied over a range of blowing ratios from 0.5 to 4.0. Coolant density ratios were maintained at values from 2.1 to 2.4. Deposition patterns generated with the cylindrical film cooling holes indicated regions of low deposition in the path of the coolant with heightened deposition between film holes. This distinctive pattern was more accentuated …
Prediction Of Tar And Light Gas During Pyrolysis Of Black Liquor And Biomass, Thomas H. Fletcher, Harland R. Pond, Jarom Webster, Judson Wooters, Larry L. Baxter
Prediction Of Tar And Light Gas During Pyrolysis Of Black Liquor And Biomass, Thomas H. Fletcher, Harland R. Pond, Jarom Webster, Judson Wooters, Larry L. Baxter
Faculty Publications
A generalized model for describing the pyrolysis behavior of low-grade fuels is being developed for incorporation into larger combustion simulation models. Light gas and tar yields from black liquor or biomass pyrolysis can be predicted using the chemical percolation devolatilization (CPD) model originally developed for coal. The initial approach is to measure the average chemical structures in a black liquor sample using 13C NMR spectroscopy. These chemical structures are then used in pyrolysis model predictions. With few changes from the coal-derived kinetic parameters, the model describes the organic pyrolysis behavior of black liquor samples obtained in a nitrogen-purged furnace. It …
Computational Analysis Of Conjugate Heat Transfer And Particulate Deposition On A High Pressure Turbine Vane, Weiguo Ai, Thomas H. Fletcher
Computational Analysis Of Conjugate Heat Transfer And Particulate Deposition On A High Pressure Turbine Vane, Weiguo Ai, Thomas H. Fletcher
Faculty Publications
Numerical computations were conducted to simulate flash deposition experiments on gas turbine disk samples with internal impingement and film cooling using a computational fluid dynamics (CFD) code (FLUENT). The standard k-epsilon turbulence model and Reynoldsaveraged Navier–Stokes were employed to compute the flow field and heat transfer. The boundary conditions were specified to be in agreement with the conditions measured in experiments performed in the BYU turbine accelerated deposition facility (TADF). A Lagrangian particle method was utilized to predict the ash particulate deposition. Userdefined subroutines were linked with FLUENT to build the deposition model. The model includes particle sticking/rebounding and particle …
Effect Of Hole Spacing On Deposition Of Fine Coal Flyash Near Film Cooling Holes, Weiguo Ai, Nathan Murray, Thomas H. Fletcher, Spencer Harding, Elizabeth Bonsignore, Jeffrey P. Bons
Effect Of Hole Spacing On Deposition Of Fine Coal Flyash Near Film Cooling Holes, Weiguo Ai, Nathan Murray, Thomas H. Fletcher, Spencer Harding, Elizabeth Bonsignore, Jeffrey P. Bons
Faculty Publications
Particulate deposition experiments were performed in a turbine accelerated deposition facility to examine the nature of flyash deposits near film cooling holes. Deposition on both bare metal and thermal barrier coating (TBC) coupons was studied, with hole spacing (s/d) of 2.25, 3.375, and 4.5. Sub-bituminous coal ash particles (mass mean diameter of 13 microns) were accelerated to a combustor exit flow Mach number of 0.25 and heated to 1183°C before impinging on a target coupon. The particle loading in the 1 h tests was 310 ppmw. Blowing ratios were varied in these experiments from 0 to 4.0 with the density …
Ballistic Imaging Of Sprays At Diesel Relevant Conditions, Jason M. Porter, S. P. Duran, T. E. Parker
Ballistic Imaging Of Sprays At Diesel Relevant Conditions, Jason M. Porter, S. P. Duran, T. E. Parker
Faculty Publications
Diesel engines are an important aspect of our transportation infrastructure, whose performance is greatly affected by the characteristics of the spray from their injectors. Characterization of the injector’s spray is therefore tantamount to clean-running efficient diesel motors. In this study, a ~15 ps pulsed Leopard D-10 laser is used along with an optical Kerr Cell to realize ballistic images of high-delivery-pressure dodecane sprays injected into a quiescent air environment at elevated temperature and pressure. Using CS2 as the Kerr switching media and by optimizing the overlap of the gate and imaging beams, an effective high speed shuttering effect is obtained. …
A Material System For Reliable Low Voltage Anodic Electrowetting, Mehdi Khodayari, Jose Carballo, Nathan B. Crane
A Material System For Reliable Low Voltage Anodic Electrowetting, Mehdi Khodayari, Jose Carballo, Nathan B. Crane
Faculty Publications
Electrowetting on dielectric is demonstrated with a thin spin-coated fluoropolymer over an aluminum electrode. Previous efforts to use thin spin-coated dielectric layers for electrowetting have shown limited success due to defects in the layers. However, when used with a citric acid electrolyte and anodic voltages, repeatable droplet actuation is achieved for 5000 cycles with an actuation of just 10 V. This offers the potential for low voltage electrowetting systems that can be manufactured with a simple low-cost process.
Coal Swelling Model For Pressurized High Particle Heating Rate Pyrolysis Applications, Randy C. Shurtz, Joseph W. Hogge, Kade C. Fowers, Gregory S. Sorensen, Thomas H. Fletcher
Coal Swelling Model For Pressurized High Particle Heating Rate Pyrolysis Applications, Randy C. Shurtz, Joseph W. Hogge, Kade C. Fowers, Gregory S. Sorensen, Thomas H. Fletcher
Faculty Publications
A model was previously developed to describe the decrease in swelling during coal pyrolysis at atmospheric pressure when maximum particle heating rates increase from 104 K/s to 105 K/s. That model included effects of coal type using chemical structure properties. This paper presents results of new experiments to study the effects of elevated pressure and high heating rates on coal pyrolysis. A pressurized flat-flame burner (PFFB) was designed and built to conduct these studies. The pyrolysis experiments reported in this paper were conducted at particle heating rates of ∼105 K/s and maximum gas temperatures of 1700 to 1900 …
Fluidic Assembly At The Microscale: Progress And Prospects, Nathan B. Crane, Onursal Onen, Jose Carballo, Qi Ni, Rasim Guldiken
Fluidic Assembly At The Microscale: Progress And Prospects, Nathan B. Crane, Onursal Onen, Jose Carballo, Qi Ni, Rasim Guldiken
Faculty Publications
Assembly permits the integration of different materials and manufacturing processes to increase system functionality. It is an essential step in the fabrication of useful systems across size scales from buildings to molecules. However, at the microscale, traditional “grasp and release” assembly methods and chemically inspired self-assembly processes are less effective due to many scaling effects. Many methods have been developed for improving microscale assembly. Often these methods include fluidic forces or the use a fluidic medium in order to enhance their performance. This paper reviews basic assembly theory and modeling methods. Three basic assembly strategies (tool-directed, process-directed, and part-directed) are …