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Faculty Publications

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Articles 181 - 210 of 914

Full-Text Articles in Chemical Engineering

Modeling Ash Deposit Growth Rates For A Wide Range Of Solid Fuels In A 100 Kw Combustor, Seyedhassan Fakourian, Zachary Mcallister, Andrew R. Fry, Yueming Wang, Xiaolong Li, Jost O.L. Wendt, Jinze Dai Mar 2021

Modeling Ash Deposit Growth Rates For A Wide Range Of Solid Fuels In A 100 Kw Combustor, Seyedhassan Fakourian, Zachary Mcallister, Andrew R. Fry, Yueming Wang, Xiaolong Li, Jost O.L. Wendt, Jinze Dai

Faculty Publications

This work details a model for evaluating the relative ash deposition propensity of various solid fuels without the complicated spatial considerations included in CFD modeling. Four deposition mechanisms are included, namely: inertial impaction, thermophoresis, condensation, and eddy impaction. This model has been validated and shown to effectively predict ash deposit rates for a wide range of solid fuels including coal, biomass, and their blends, burned in a 100 kW rated downflow combustor. Specifically, this work presents and compares two separate models for the sticking efficiency of impacting ash particles on a coupon surface: the melt fraction stickiness …


Coarse-Grained Simulation Of Pegylated And Tethered Protein Devices At All Experimentally Accessible Surface Residues On Β-Lactamase For Stability Analysis And Comparison, Addison K. Smith, Mehran Sultani, Joshua Wilkerson, Brandon Timmerman, Emily Long Zhao, Bradley C. Bundy, Thomas A. Knotts Feb 2021

Coarse-Grained Simulation Of Pegylated And Tethered Protein Devices At All Experimentally Accessible Surface Residues On Β-Lactamase For Stability Analysis And Comparison, Addison K. Smith, Mehran Sultani, Joshua Wilkerson, Brandon Timmerman, Emily Long Zhao, Bradley C. Bundy, Thomas A. Knotts

Faculty Publications

PEGylated and surface-tethered proteins are used in a variety of biotechnological applications, but traditional methods offer little control over the placement of the functionalization sites on the protein. Fortunately, recent experimental methods functionalize the protein at any location on the amino acid sequence, so the question becomes one of selecting the site that will result in the best protein function. This work shows how molecular simulation can be used to screen potential attachment sites for surface tethering or PEGylation. Previous simulation work has shown promise in this regard for a model protein, but these studies are limited to screening only …


Editors’ Choice-Power-Generating Electrochemical Co2 Scrubbing From Air Enabling Practical Aemfc Application, Yiwei Zheng, Garrett Huang, Mrinmay Mandal, John R. Varcoe, Paul A. Kohl, William E. Mustain Feb 2021

Editors’ Choice-Power-Generating Electrochemical Co2 Scrubbing From Air Enabling Practical Aemfc Application, Yiwei Zheng, Garrett Huang, Mrinmay Mandal, John R. Varcoe, Paul A. Kohl, William E. Mustain

Faculty Publications

Anion exchange membrane fuel cells (AEMFCs) have been widely touted as a low-cost alternative to existing proton exchange membrane fuel cells. However, AEMFCs operating on air suffer from a severe performance penalty caused by carbonation from exposure to CO2. Many approaches to removing CO2 from the cathode inlet would consume valuable energy and complicate the systems-level balance-of-plant. Therefore, this work focuses on an electrochemical solution where CO2 removal would still generate power, but not expose an entire AEMFC stack to carbonation conditions. Such a system consists of two AEMFCs in series. The first AEMFC, which acts as an anion exchange …


Effect Of Membrane Properties On The Carbonation Of Anion Exchange Membrane Fuel Cells, Yiwei Zheng, Lyzmarie Nicole Irizarry, Noor Ui Hassan, Eric R. Williams, Morgan Stefik, Jacob M. Lamanna, Daniel S. Hussey, Mustain E William Jan 2021

Effect Of Membrane Properties On The Carbonation Of Anion Exchange Membrane Fuel Cells, Yiwei Zheng, Lyzmarie Nicole Irizarry, Noor Ui Hassan, Eric R. Williams, Morgan Stefik, Jacob M. Lamanna, Daniel S. Hussey, Mustain E William

Faculty Publications

Anion exchange membrane fuel cells (AEMFC) are potentially very low-cost replacements for proton exchange membrane fuel cells. However, AEMFCs suffer from one very serious drawback: significant performance loss when CO2 is present in the reacting oxidant gas (e.g., air) due to carbonation. Although the chemical mechanisms for how carbonation leads to voltage loss in operating AEMFCs are known, the way those mechanisms are affected by the properties of the anion exchange membrane (AEM) has not been elucidated. Therefore, this work studies AEMFC carbonation using numerous high-functioning AEMs from the literature and it was found that the ionic conductivity of the …


3d-Printed Microfluidic Droplet Generator With Hydrophilic And Hydrophobic Polymers, Chandler A. Warr, Hunter S. Hinnen, Saroya Avery, Rebecca J. Cate, Gregory P. Nordin, William G. Pitt Jan 2021

3d-Printed Microfluidic Droplet Generator With Hydrophilic And Hydrophobic Polymers, Chandler A. Warr, Hunter S. Hinnen, Saroya Avery, Rebecca J. Cate, Gregory P. Nordin, William G. Pitt

Faculty Publications

Droplet generation has been widely used in conventional two-dimensional (2D) microfluidic devices, and has recently begun to be explored for 3D-printed droplet generators. A major challenge for 3D-printed devices is preventing water-in-oil droplets from sticking to the interior surfaces of the droplet generator when the device is not made from hydrophobic materials. In this study, two approaches were investigated and shown to successfully form droplets in 3D-printed microfluidic devices. First, several printing resin candidates were tested to evaluate their suitability for droplet formation and material properties. We determined that a hexanediol diacrylate/lauryl acrylate (HDDA/LA) resin forms a solid polymer that …


3d-Printed Microfluidic Droplet Generator With Hydrophilic And Hydrophobic Polymers, Chandler A. Warr, Hunter S. Hinnen, Saroya Avery, Rebecca J. Cate, Gregory P. Nordin, William G. Pitt Jan 2021

3d-Printed Microfluidic Droplet Generator With Hydrophilic And Hydrophobic Polymers, Chandler A. Warr, Hunter S. Hinnen, Saroya Avery, Rebecca J. Cate, Gregory P. Nordin, William G. Pitt

Faculty Publications

Droplet generation has been widely used in conventional two-dimensional (2D) microfluidic devices, and has recently begun to be explored for 3D-printed droplet generators. A major challenge for 3D-printed devices is preventing water-in-oil droplets from sticking to the interior surfaces of the droplet generator when the device is not made from hydrophobic materials. In this study, two approaches were investigated and shown to successfully form droplets in 3D-printed microfluidic devices. First, several printing resin candidates were tested to evaluate their suitability for droplet formation and material properties. We determined that a hexanediol diacrylate/lauryl acrylate (HDDA/LA) resin forms a solid polymer that …


Kinetics Study Of The Hydrodeoxygenation Of Xylitol Over A ReoX-Pd/Ceo2 Catalyst, Blake Macqueen, Michael Royko, Bradie S. Crandall, Andreas Heyden, Yomaira J. Pagán-Torres, Jochen A. Lauterbach Jan 2021

Kinetics Study Of The Hydrodeoxygenation Of Xylitol Over A ReoX-Pd/Ceo2 Catalyst, Blake Macqueen, Michael Royko, Bradie S. Crandall, Andreas Heyden, Yomaira J. Pagán-Torres, Jochen A. Lauterbach

Faculty Publications

In this study, we elucidate the reaction kinetics for the simultaneous hydrodeoxygenation of xylitol to 1,2-dideoxypentitol and 1,2,5-pentanetriol over a ReOx-Pd/CeO2 (2.0 weight% Re, 0.30 weight% Pd) catalyst. The reaction was determined to be a zero-order reaction with respect to xylitol. The activation energy was elucidated through an Arrhenius relationship as well as non-Arrhenius kinetics. The Arrhenius relationship was investigated at 150–170◦ C and a constant H2 pressure of 10 bar resulting in an activation energy of 48.7 ± 10.5 kJ/mol. The investigation of non-Arrhenius kinetics was conducted at 120–170◦ C and a sub-Arrhenius relation was elucidated with activation energy …


Kinetics Study Of The Hydrodeoxygenation Of Xylitol Over A ReoX-Pd/Ceo2 Catalyst, Blake Macqueen, Michael Royko, Bradie S. Crandall, Andreas Heyden, Yomaira J. Pagán-Torres, Jochen A. Lauterbach Jan 2021

Kinetics Study Of The Hydrodeoxygenation Of Xylitol Over A ReoX-Pd/Ceo2 Catalyst, Blake Macqueen, Michael Royko, Bradie S. Crandall, Andreas Heyden, Yomaira J. Pagán-Torres, Jochen A. Lauterbach

Faculty Publications

In this study, we elucidate the reaction kinetics for the simultaneous hydrodeoxygenation of xylitol to 1,2-dideoxypentitol and 1,2,5-pentanetriol over a ReOx-Pd/CeO2 (2.0 weight% Re, 0.30 weight% Pd) catalyst. The reaction was determined to be a zero-order reaction with respect to xylitol. The activation energy was elucidated through an Arrhenius relationship as well as non-Arrhenius kinetics. The Arrhenius relationship was investigated at 150–170◦ C and a constant H2 pressure of 10 bar resulting in an activation energy of 48.7 ± 10.5 kJ/mol. The investigation of non-Arrhenius kinetics was conducted at 120–170◦ C and a sub-Arrhenius relation was elucidated with activation energy …


One-Dimensional Turbulence (Odt): Computationally Efficient Modeling And Simulation Of Turbulent Flows, Victoria B. Stephens, David O. Lignell Dec 2020

One-Dimensional Turbulence (Odt): Computationally Efficient Modeling And Simulation Of Turbulent Flows, Victoria B. Stephens, David O. Lignell

Faculty Publications

One-dimensional turbulence (ODT) is an accurate and computationally efficient model for simulating turbulent flows. ODT has been applied to a wide range of flow problems including reaction, multiphase, differential diffusion, heat release, buoyancy, and wall flows. Applications include use as a standalone model and as a closure for large-eddy simulation (LES). Its strength lies in the ability to capture a full range of turbulent length and time scales. The ODT model is strongly coupled with its implementation, complicating its formulations. We present a modern, open-source, object-oriented C++ implementation of ODT. The code described here and made available online can be …


A Computational Investigation Of The Interstitial Oxidation Thermodynamics Of A Mo-Nb-Ta-W High Entropy Alloy Beyond The Dilute Regime, Adib J. Samin Dec 2020

A Computational Investigation Of The Interstitial Oxidation Thermodynamics Of A Mo-Nb-Ta-W High Entropy Alloy Beyond The Dilute Regime, Adib J. Samin

Faculty Publications

High entropy alloys (HEAs) are promising candidates for high-temperature structural material applications. Oxidation is a major factor that must be accounted for when designing such materials and it is thus important to study the oxidation behavior of HEAs to enable the optimum design of next generation materials. In this study, the thermodynamic behavior of interstitial oxygen in a Mo-Nb-Ta-W high entropy alloy was explored beyond the dilute limit. This was accomplished by sampling configurations of the HEA and HEA-oxygen systems from an isothermal–isobaric ensemble using a series of first-principle-based Monte Carlo simulations. It was found that the interstitial oxygen had …


Noise And Detectivity Limits In Organic Shortwave Infrared Photodiodes With Low Disorder, Zhenghui Wu, Ning Li, Naresh Eedugurala, Jason D. Azoulay, Dong Seok Leem, Tse Nga Ng Dec 2020

Noise And Detectivity Limits In Organic Shortwave Infrared Photodiodes With Low Disorder, Zhenghui Wu, Ning Li, Naresh Eedugurala, Jason D. Azoulay, Dong Seok Leem, Tse Nga Ng

Faculty Publications

© 2020, The Author(s). To achieve high detectivity in infrared detectors, it is critical to reduce the device noise. However, for non-crystalline semiconductors, an essential framework is missing to understand and predict the effects of disorder on the dark current. This report presents experimental and modeling studies on the noise current in exemplar organic bulk heterojunction photodiodes, with 10 donor–acceptor combinations spanning wavelength between 800 and 1600 nm. A significant reduction of the noise and higher detectivity were found in devices using non-fullerene acceptors (NFAs) in comparison to those using fullerene derivatives. The low noise in NFA blends was attributed …


Homotopy Simulation Of Dissipative Micropolar Flow And Heat Transfer From A Two-Dimensional Body With Heat Sink Effect: Applications In Polymer Coating, O. A. Bég, B. Vasu, A. K. Ray, T. A. Beg, A. Kadir, H. J. Leonard, Rama S. R. Gorla Dec 2020

Homotopy Simulation Of Dissipative Micropolar Flow And Heat Transfer From A Two-Dimensional Body With Heat Sink Effect: Applications In Polymer Coating, O. A. Bég, B. Vasu, A. K. Ray, T. A. Beg, A. Kadir, H. J. Leonard, Rama S. R. Gorla

Faculty Publications

Non-Newtonian flow from a wedge constitutes a fundamental problem in chemical engineering systems and is relevant to processing of polymers, coating systems, etc. Motivated by such applications, the homotopy analysis method (HAM) was employed to obtain semi-analytical solutions for thermal convection boundary layer flow of incompressible micropolar fluid from a two-dimensional body (wedge). Viscous dissipation and heat sink effects were included. The non-dimensional boundary value problem emerges as a system of nonlinear coupled ordinary differential equations, by virtue of suitable coordinate transformations. The so-called Falkner-Skan flow cases are elaborated. Validation of the HAM solutions was achieved with earlier simpler models, …


Swarm-Based Design Of Proportional Integral And Derivative Controllers Using A Compromise Cost Function: An Arduino Temperature Laboratory Case Study, Paulo De Moura Oliveira, John Hedengren, Eduardo Solteiro Pires Nov 2020

Swarm-Based Design Of Proportional Integral And Derivative Controllers Using A Compromise Cost Function: An Arduino Temperature Laboratory Case Study, Paulo De Moura Oliveira, John Hedengren, Eduardo Solteiro Pires

Faculty Publications

Simple and easy to use methods are of great practical demand in the design of Proportional, Integral, and Derivative (PID) controllers. Controller design criteria are to achieve a good set-point tracking and disturbance rejection with minimal actuator variation. Achieving satisfactory trade-offs between these performance criteria is not easily accomplished with classical tuning methods. A particle swarm optimization technique is proposed to design PID controllers. The design method minimizes a compromise cost function based on both the integral absolute error and control signal total variation criteria. The proposed technique is tested on an Arduino-based Temperature Control Laboratory (TCLab) and compared with …


Using Reactive Dissipative Particle Dynamics To Understand Local Shape Manipulation Of Polymer Vesicles, Qinyu Zhu, Timothy R. Scott, Douglas R. Tree Oct 2020

Using Reactive Dissipative Particle Dynamics To Understand Local Shape Manipulation Of Polymer Vesicles, Qinyu Zhu, Timothy R. Scott, Douglas R. Tree

Faculty Publications

Biological cells have long been of interest to researchers due to their capacity to actively control their shape. Accordingly, there is significant interest in generating simplified synthetic protocells that can alter their shape based on an externally or internally generated stimulus. To date, most progress has been made towards controlling the global shape of a protocell, whereas less is known about generating a local shape change. Here, we seek to better understand the possible mechanisms for producing local morphological changes in a popular protocell system, the block copolymer vesicle. Accordingly, we have combined Dissipative Particle Dynamics (DPD) and the Split …


Mechanisms Of Asymmetric Membrane Formation In Nonsolvent-Induced Phase Separation, Jan Ulric Garcia, Tatsuhiro Iwama, Eva Y. Chan, Douglas R. Tree, Kris T. Delaney, Glenn H. Fredrickson Oct 2020

Mechanisms Of Asymmetric Membrane Formation In Nonsolvent-Induced Phase Separation, Jan Ulric Garcia, Tatsuhiro Iwama, Eva Y. Chan, Douglas R. Tree, Kris T. Delaney, Glenn H. Fredrickson

Faculty Publications

We report the first simulations of nonsolvent-induced phase separation (NIPS) that predict membrane microstructures with graded asymmetric pore size distribution. In NIPS, a polymer solution film is immersed in a nonsolvent bath, enriching the film in nonsolvent, and leading to phase separation that forms a solid polymer-rich membrane matrix and polymer-poor membrane pores. We demonstrate how mass-transfer-induced spinodal decomposition, thermal fluctuations, and glass-transition dynamics—implemented with mobility contrast between the polymer-rich and polymer-poor phases—are essential to the formation of asymmetric membrane microstructures. Specifically, we show that the competition between the propagation of the phase-separation and glass-transition fronts determines the degree of …


Development Of Metallic Nuclear Material Purification Process Via Simultaneous Chlorination And Volatilization, Parker Okabe, Devin Rappleye, Matthew Newton, Michael F. Simpson Oct 2020

Development Of Metallic Nuclear Material Purification Process Via Simultaneous Chlorination And Volatilization, Parker Okabe, Devin Rappleye, Matthew Newton, Michael F. Simpson

Faculty Publications

A purification process involving simultaneous chlorination and volatilization is reported using aluminum, iron, gallium, and uranium separation from cerium metal as the demonstration system. Anhydrous Cl2 gas was reacted with the metal after it had been converted to small particles of hydride at temperatures ranging from 523 to 973 K. Each of the impurities should form chlorides with relatively high saturated vapor pressures. The objective of the process was to volatilize these chlorides after first achieving near-complete conversion of the metals to hydride and then chlorides. Complete conversion of hydrides to chlorides could not be achieved using …


Bio-Oils From Vacuum Ablative Pyrolysis Of Torrefied Tobacco Residues, Nattawut Khuenkaeo, Blake Macqueen, Thossaporn Onsree, Sangu Daiya, Nakorn Tippayawong, Jochen A. Lauterbach Sep 2020

Bio-Oils From Vacuum Ablative Pyrolysis Of Torrefied Tobacco Residues, Nattawut Khuenkaeo, Blake Macqueen, Thossaporn Onsree, Sangu Daiya, Nakorn Tippayawong, Jochen A. Lauterbach

Faculty Publications

Fast pyrolysis, in combination with torrefaction pretreatment, was used to convert tobacco residues to value-added bio-fuels and chemicals. Tobacco plant residues were torrefied at 220, 260, and 300 °C, before being pyrolyzed at 450, 500, 550, and 600 °C in a rotating blade ablative reactor under vacuum conditions to test the effects on product yields. With torrefaction, tobacco residues thermally decomposed 20-25% w/w at low temperatures. Torrefaction and pyrolysis temperatures were found to markedly affect pyrolytic product yields of bio-chars and bio-oils, while having no effect on gas-phase products. Bio-oil yields exhibited a direct relation with pyrolysis temperature and an …


Bio-Oils From Vacuum Ablative Pyrolysis Of Torrefied Tobacco Residues, Nattawut Khuenkaeo, Blake Macqueen, Thossaporn Onsree, Sangu Daiya, Nakorn Tippayawong, Jochen A. Lauterbach Sep 2020

Bio-Oils From Vacuum Ablative Pyrolysis Of Torrefied Tobacco Residues, Nattawut Khuenkaeo, Blake Macqueen, Thossaporn Onsree, Sangu Daiya, Nakorn Tippayawong, Jochen A. Lauterbach

Faculty Publications

Fast pyrolysis, in combination with torrefaction pretreatment, was used to convert tobacco residues to value-added bio-fuels and chemicals. Tobacco plant residues were torrefied at 220, 260, and 300 °C, before being pyrolyzed at 450, 500, 550, and 600 °C in a rotating blade ablative reactor under vacuum conditions to test the effects on product yields. With torrefaction, tobacco residues thermally decomposed 20-25% w/w at low temperatures. Torrefaction and pyrolysis temperatures were found to markedly affect pyrolytic product yields of bio-chars and bio-oils, while having no effect on gas-phase products. Bio-oil yields exhibited a direct relation with pyrolysis temperature and an …


Challenges To Levulinic Acid And Humins Valuation In The Sugarcane Bagasse Biorefinery Concept, Emília Savioli Lopes, Jean Felipe Leal Silva, Elmer Ccopa Rivera, Alana Petrina Gomes, Melina Savioli Lopes, Rubens Maciel Filho, Laura Plazas Tovar Sep 2020

Challenges To Levulinic Acid And Humins Valuation In The Sugarcane Bagasse Biorefinery Concept, Emília Savioli Lopes, Jean Felipe Leal Silva, Elmer Ccopa Rivera, Alana Petrina Gomes, Melina Savioli Lopes, Rubens Maciel Filho, Laura Plazas Tovar

Faculty Publications

© 2020, Springer Science+Business Media, LLC, part of Springer Nature. Levulinic acid (LA) is currently one of the most promising chemicals derived from biomass. However, its large-scale production is hampered by the challenges in biomass hydrolysis and the poor selectivity due to the formation of humins (HUs). This study addresses these challenges using the biorefinery concept of biomass fractionation. A three-step process (pretreatment, delignification, and acid-catalyzed conversion) was optimized to produce LA from SCB considering the yield (YLA), efficiency (ELA), and concentration of LA (CLA) as functions of temperature, reaction time, acid concentration, and solids loading. By means of a …


A Review Of Coal Heating Value Correlations With Application To Coal Char, Tar, And Other Fuels, Andrew P. Richards, Denver Haycock, Jacob F. Frandsen, Thomas H. Fletcher Aug 2020

A Review Of Coal Heating Value Correlations With Application To Coal Char, Tar, And Other Fuels, Andrew P. Richards, Denver Haycock, Jacob F. Frandsen, Thomas H. Fletcher

Faculty Publications

Accurately measuring a fuel’s heating value is one of the first steps in the classification of a new fuel. Heating values are widely used in coal combustion research and are becoming more useful in other fuel types as well. Many different empirical correlations to predict heating values based on primary organic (CHONS) elemental composition are found in the literature, many of which were originally created to predict heating values of parent coal, and some of which have been extended for biomass. However, no correlations exist for heating values of coal chars and tars. Thirteen literature heating value correlations (10 model …


Air Quality Improvement During Triple-Lockdown In The Coastal City Of Kannur, Kerala To Combat Covid-19 Transmission, C. T. Resmi, T. Nishanth, M. K. Satheesh Kumar, M. G. Manoj, M. Balachandramohan, K. T. Valsaraj Jul 2020

Air Quality Improvement During Triple-Lockdown In The Coastal City Of Kannur, Kerala To Combat Covid-19 Transmission, C. T. Resmi, T. Nishanth, M. K. Satheesh Kumar, M. G. Manoj, M. Balachandramohan, K. T. Valsaraj

Faculty Publications

The novel SARS-CoV-2 coronavirus that emerged in the city of Wuhan, China, last year has since become the COVID-19 pandemic across all continents. To restrict the spread of the virus pandemic, the Government of India imposed a lockdown from 25 March 2020. In India, Kannur district was identified as the first "hotspot" of virus transmission and a "triple-lockdown" was implemented for a span of twenty days from 20 April 2020. This article highlights the variations of surface O-3, NO, NO2, CO, SO2, NH3, VOC's, PM10, PM2.5 and meteorological parameters at the time of pre-lockdown, lockdown and triple-lockdown days at Kannur …


Effect Of Dilution On Sedimentational Separation Of Bacteria From Blood, Clifton M. Anderson, William G. Pitt Jul 2020

Effect Of Dilution On Sedimentational Separation Of Bacteria From Blood, Clifton M. Anderson, William G. Pitt

Faculty Publications

Bacteria must be separated from septic whole blood in preparation for rapid antibiotic susceptibility tests. This work improves upon past work isolating bacteria from whole blood by exploring an important experimental factor: Whole blood dilution. Herein, we use the continuity equation to model red blood cell sedimentation and show that overall spinning time decreases as the blood is diluted. We found that the bacteria can also be captured more efficiently from diluted blood, up to approximately 68 ± 8% recovery (95% confidence interval). However, diluting blood both requires and creates extra fluid that end users must handle; an optimal dilution, …


Survey Of 8 Uav Set-Covering Algorithms For Terrain Photogrammetry, Joshua Hammond, Cory Vernon, Trent Okeson, Benjamin Barrett, Samuel Arce, Valerie Newell, Joseph Janson, Kevin Franke, John Hedengren Jul 2020

Survey Of 8 Uav Set-Covering Algorithms For Terrain Photogrammetry, Joshua Hammond, Cory Vernon, Trent Okeson, Benjamin Barrett, Samuel Arce, Valerie Newell, Joseph Janson, Kevin Franke, John Hedengren

Faculty Publications

Remote sensing with unmanned aerial vehicles (UAVs) facilitates photogrammetry for environmental and infrastructural monitoring. Models are created with less computational cost by reducing the number of photos required. Optimal camera locations for reducing the number of photos needed for structure-from-motion (SfM) are determined through eight mathematical set-covering algorithms as constrained by solve time. The algorithms examined are: traditional greedy, reverse greedy, carousel greedy (CG), linear programming, particle swarm optimization, simulated annealing, genetic, and ant colony optimization. Coverage and solve time are investigated for these algorithms. CG is the best method for choosing optimal camera locations as it balances number of …


Automated 3d Reconstruction Using Optimized View-Planning Algorithms For Iterative Development Of Structure-From-Motion Models, Samuel Arce, Cory Vernon, Joshua Hammond, Valerie Newell, Joseph Janson, Kevin Franke, John Hedengren Jul 2020

Automated 3d Reconstruction Using Optimized View-Planning Algorithms For Iterative Development Of Structure-From-Motion Models, Samuel Arce, Cory Vernon, Joshua Hammond, Valerie Newell, Joseph Janson, Kevin Franke, John Hedengren

Faculty Publications

Unsupervised machine learning algorithms (clustering, genetic, and principal component analysis) automate Unmanned Aerial Vehicle (UAV) missions as well as the creation and refinement of iterative 3D photogrammetric models with a next best view (NBV) approach. The novel approach uses Structure-from-Motion (SfM) to achieve convergence to a specified orthomosaic resolution by identifying edges in the point cloud and planning cameras that “view” the holes identified by edges without requiring an initial model. This iterative UAV photogrammetric method successfully runs in various Microsoft AirSim environments. Simulated ground sampling distance (GSD) of models reaches as low as 3.4 cm per pixel, and generally, …


0.03 V Electrolysis Voltage Driven Hydrazine Assisted Hydrogen Generation On Nico Phosphide Nanowires Supported Nicohydroxide Nanosheets, Mujie Li, Zhongyi Zhang, Hailang Xiong, Linan Wang, Shuxian Zhuang, Morris D. Argyle, Yang Tang, Xiaojin Yang, Yongmei Chen, Pingyu Wan, Maohong Fan Jul 2020

0.03 V Electrolysis Voltage Driven Hydrazine Assisted Hydrogen Generation On Nico Phosphide Nanowires Supported Nicohydroxide Nanosheets, Mujie Li, Zhongyi Zhang, Hailang Xiong, Linan Wang, Shuxian Zhuang, Morris D. Argyle, Yang Tang, Xiaojin Yang, Yongmei Chen, Pingyu Wan, Maohong Fan

Faculty Publications

In order to decrease the electricity consumption of hydrogen generation, hydrazine-assisted water electrolysis is intensively investigated recently. Herein, hierarchical nanostructure of ultrathin NiCo(OH)x nanosheets (NSs) that in-situ grown on the NiCoP nanowires (NWs) was deposited on nickel foam (NF) to construct NiCo(OH)x@NiCoP/NF electrode. NiCoP NWs extend the surface area, spatial utilization of NF and enhance the electron conduction to the outmost NiCo(OH)x NSs. NiCo(OH)x NSs interlace to form regular mesoporous channels, which improve the structural stability and mass transfer rate. Moreover, NiCoP NWs enhance the adsorption of protons and the transfer of electrons, while NiCo(OH) …


Effects Of Temperature And Antioxidants On The Oxidation Of Biodiesel Derived From Waste Vegetable Oil, Randy L. Maglinao, Torrey J. Wagner, Keegan Duff Jun 2020

Effects Of Temperature And Antioxidants On The Oxidation Of Biodiesel Derived From Waste Vegetable Oil, Randy L. Maglinao, Torrey J. Wagner, Keegan Duff

Faculty Publications

Biodiesel offers several environmental benefits and improvements to some fuel performance properties, but its poor oxidative stability has been a major concern. Currently, the accepted practice to improve biodiesel oxidative stability is the addition of antioxidants; numerous antioxidants have been studied but their effectiveness in inhibiting biodiesel oxidation is difficult to predict due to variation with resonance stability, solubility, reactivity, and volatility. To improve prediction efforts, this study explored the Rapid Small-Scale Oxidation Test (RSSOT) as a means to investigate how biodiesel oxidation is affected by antioxidant concentration and temperature, and compared its results with the oxidative stability index test. …


Model Predictive Control And Estimation Of Managed Pressure Drilling Using A Real-Time High Fidelity Flow Model, Junho Park, Cameron Price, David Pixton, Manuel Aghito, Roar Nybø, Knut Bjørkevoll, John Hedengren May 2020

Model Predictive Control And Estimation Of Managed Pressure Drilling Using A Real-Time High Fidelity Flow Model, Junho Park, Cameron Price, David Pixton, Manuel Aghito, Roar Nybø, Knut Bjørkevoll, John Hedengren

Faculty Publications

When drilling an oil or gas well, well pressures may be controlled using a technology called managed pressure drilling. This technology often relies on model predictive control schemes; however, practical limitations have generally led to the use of simplified controller models that do not optimally handle certain perturbations in the physical system. The present work reports on the first implementation of a highly accurate system model that has been adapted for real-time use in a controller. This real-time high-fidelity model approximates the results of offline high-fidelity models without requiring operation by model experts. The effectiveness of the model is demonstrated …


Kinetic Insights Into The Lignocellulosic Biomass-Based Levulinic Acid Production By A Mechanistic Model, Emília Savioli Lopes, Elmer Ccopa Rivera, Julio César De Jesus Gariboti, Luis Henrique Zimmermann Feistel, João Vitor Dutra, Rubens Maciel Filho, Laura Plazas Tovar May 2020

Kinetic Insights Into The Lignocellulosic Biomass-Based Levulinic Acid Production By A Mechanistic Model, Emília Savioli Lopes, Elmer Ccopa Rivera, Julio César De Jesus Gariboti, Luis Henrique Zimmermann Feistel, João Vitor Dutra, Rubens Maciel Filho, Laura Plazas Tovar

Faculty Publications

© 2020, Springer Nature B.V. Abstract: In this work, a mechanistic model was developed to simulate the kinetics of the production of levulinic acid (LA) from sugarcane bagasse (SCB), rice husk (RH) and soybean straw (SS). The production of LA from those agro-industrial wastes followed the methodology of biorefining in three stages. Experimental data from the third stage (catalytic depolymerization of cellulose) obtained under a wide range of operating conditions were used to estimate the parameters of the model. An optimization procedure based on a genetic algorithm was used to determine the optimal parameter values. The prediction of the concentrations …


Chemical And Thermal Sintering Of Supported Metals With Emphasis On Cobalt Catalysts During Fischer−Tropsch Synthesis, Mahmood Rahmati, Mohammad-Saeed Safdari, Thomas H. Fletcher, Morris D. Argyle, Calvin H. Bartholomew May 2020

Chemical And Thermal Sintering Of Supported Metals With Emphasis On Cobalt Catalysts During Fischer−Tropsch Synthesis, Mahmood Rahmati, Mohammad-Saeed Safdari, Thomas H. Fletcher, Morris D. Argyle, Calvin H. Bartholomew

Faculty Publications

This comprehensive critical review combines, for the first time, recent advances in nanoscale surface chemistry, surface science, DFT, adsorption calorimetry, and in situ XRD and TEM to provide new insights into catalyst sintering. This work provides qualitative and quantitative estimates of the extent and rate of sintering as functions of nanocrystal (NC) size, temperature, and atmosphere. This review is unique in that besides summarizing important, useful data from previous studies, it also advances the field through addition of (i) improved or new models, (ii) new data summarized in original tables and figures, and (iii) new fundamental perspectives into sintering of …


Turbulence Modulation In Particle-Laden Stationary Homogeneous Isotropic Turbulence Using One-Dimensional Turbulence, Marco Fistler, Alan Kerstein, David O. Lignell, Michael Oevermann Apr 2020

Turbulence Modulation In Particle-Laden Stationary Homogeneous Isotropic Turbulence Using One-Dimensional Turbulence, Marco Fistler, Alan Kerstein, David O. Lignell, Michael Oevermann

Faculty Publications

Turbulence modulation in particle-laden stationary homogeneous isotropic turbulence is investigated using one-dimensional turbulence (ODT), a low-dimensional stochastic flow simulation model. For this purpose, ODT is extended in two ways. First, a forcing scheme that maintains statistical stationarity is introduced. Unlike direct numerical simulation (DNS) of forced turbulence, the ODT framework accommodates forcing that is not directly coupled to the momentum equation. For given forcing the ODT energy dissipation rate is therefore the same in particle-laden cases as in the corresponding single-phase reference case. Second, previously implemented one-way-coupled particle phenomenology is extended to two-way coupling using the general ODT methodology for …