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Articles 151 - 180 of 914
Full-Text Articles in Chemical Engineering
Thermosensitive Polymers And Thermo-Responsive Liposomal Drug Delivery Systems, Waad H. Abuwatfa, Nahid S. Awad, William G. Pitt, Ghaleb A. Husseini
Thermosensitive Polymers And Thermo-Responsive Liposomal Drug Delivery Systems, Waad H. Abuwatfa, Nahid S. Awad, William G. Pitt, Ghaleb A. Husseini
Faculty Publications
Temperature excursions within a biological milieu can be effectively used to induce drug release from thermosensitive drug-encapsulating nanoparticles. Oncological hyperthermia is of particular interest, as it is proven to synergistically act to arrest tumor growth when combined with optimally-designed smart drug delivery systems (DDSs). Thermoresponsive DDSs aid in making the drugs more bioavailable, enhance the therapeutic index and pharmacokinetic trends, and provide the spatial placement and temporal delivery of the drug into localized anatomical sites. This paper reviews the fundamentals of thermosensitive polymers, with a particular focus on thermoresponsive liposomal-based drug delivery systems.
Gibbs–Duhem Relation For Phase-Field Models Of Polymeric Mixtures, Rami Alhasan, Douglas R. Tree
Gibbs–Duhem Relation For Phase-Field Models Of Polymeric Mixtures, Rami Alhasan, Douglas R. Tree
Faculty Publications
Phase-field models are relatively inexpensive field-based models capable of capturing the nonequilibrium multiphase behavior of polymers and other soft materials. With their rise in popularity over the past several years, questions have arisen concerning the thermodynamic consistency of some model formulations. In doing so, researchers have employed several different forms of the Gibbs–Duhem equation─a classical thermodynamic relationship used to assess consistency─leading to questions about the correct form of this expression for inhomogeneous mixtures. In this paper, we derive a generalized Gibbs–Duhem relation that is valid for phase-field models. The key to the derivation is the recognition that the functional derivatives …
A Phase Field Model For Dynamic Simulations Of Reactive Blending Of Polymers, Mukul D. Tikekar, Kris T. Delaney, Michael C. Villet, Douglas R. Tree
A Phase Field Model For Dynamic Simulations Of Reactive Blending Of Polymers, Mukul D. Tikekar, Kris T. Delaney, Michael C. Villet, Douglas R. Tree
Faculty Publications
A facile way to generate compatibilized blends of immiscible polymers is through reactive blending of end-functionalized homopolymers. The reaction may be reversible or irreversible depending on the end-groups and is affected by the immiscibility and transport of the reactant homopolymers and the compatibilizing copolymer product. Here we describe a phase-field framework to model the combined dynamics of reaction kinetics, diffusion, and multi-component thermodynamics on the evolution of the microstructure and reaction rate in reactive blending. A density functional with no fitting parameters, which is obtained by adapting a framework of Uneyama and Doi and qualitatively agrees with self-consistent field theory, …
Review—Concentration Measurements In Molten Chloride Salts Using Electrochemical Methods, Tyler Williams, Rankin Shum, Devin Rappleye
Review—Concentration Measurements In Molten Chloride Salts Using Electrochemical Methods, Tyler Williams, Rankin Shum, Devin Rappleye
Faculty Publications
The electrochemical measurement of concentration in molten chloride salts is a valuable tool for the control of existing and potential industrial processes, recycling of precious materials and energy production. The electrochemical techniques commonly used to measure concentration and each techniques’ associated theory are discussed. Practices which improve measurement accuracy and precision are set forth. Exceptionally accurate and precise measurements published in the literature are evaluated based on their performance in specified concentration ranges. The strengths and weaknesses of the most accurate measurements are briefly explored. Chronopotentiometry (CP) and square wave voltammetry (SWV) are accurate and precise with low concentration measurements. …
Approaching Disorder-Tolerant Semiconducting Polymers, Xinwen Yan, Miao Xiong, Xin Yu Deng, Kai Kai Liu, Jia Tong Li, Xue Qing Wang, Song Zhang, Nathaniel Prine, Zhuoqiong Zhang, Wanying Huang, Yishan Wang, Jie Yu Wang, Xiaodan Gu, Shu Kong So, Jia Zhu, Ting Lei
Approaching Disorder-Tolerant Semiconducting Polymers, Xinwen Yan, Miao Xiong, Xin Yu Deng, Kai Kai Liu, Jia Tong Li, Xue Qing Wang, Song Zhang, Nathaniel Prine, Zhuoqiong Zhang, Wanying Huang, Yishan Wang, Jie Yu Wang, Xiaodan Gu, Shu Kong So, Jia Zhu, Ting Lei
Faculty Publications
Doping has been widely used to control the charge carrier concentration in organic semiconductors. However, in conjugated polymers, n-doping is often limited by the tradeoff between doping efficiency and charge carrier mobilities, since dopants often randomly distribute within polymers, leading to significant structural and energetic disorder. Here, we screen a large number of polymer building block combinations and explore the possibility of designing n-type conjugated polymers with good tolerance to dopant-induced disorder. We show that a carefully designed conjugated polymer with a single dominant planar backbone conformation, high torsional barrier at each dihedral angle, and zigzag backbone curvature is highly …
Semiflexible Oligomers Crystallize Via A Cooperative Phase Transition, Pierre Kawak, Dakota S. Banks, Douglas R. Tree
Semiflexible Oligomers Crystallize Via A Cooperative Phase Transition, Pierre Kawak, Dakota S. Banks, Douglas R. Tree
Faculty Publications
Semicrystalline polymers are ubiquitous, yet despite their fundamental and industrial importance, the theory of homogeneous nucleation from a melt remains a subject of debate. A key component of the controversy is that polymer crystallization is a non-equilibrium process, making it difficult to distinguish between effects that are purely kinetic and those that arise from the underlying thermodynamics. Due to computational cost constraints, simulations of polymer crystallization typically employ non-equilibrium molecular dynamics techniques with large degrees of undercooling that further exacerbate the coupling between thermodynamics and kinetics. In a departure from this approach, in this study, we isolate the near-equilibrium nucleation …
Stochastic Modeling Of Surface Scalar-Flux Fluctuations In Turbulent Channel Flow Using One-Dimensional Turbulence, Marten Klein, Heiko Schmidt, David O. Lignell
Stochastic Modeling Of Surface Scalar-Flux Fluctuations In Turbulent Channel Flow Using One-Dimensional Turbulence, Marten Klein, Heiko Schmidt, David O. Lignell
Faculty Publications
Accurate and economical modeling of near-surface transport processes is a standing challenge for various engineering and atmospheric boundary-layer flows. In this paper, we address this challenge by utilizing an economical stochastic one-dimensional turbulence (ODT) model. ODT aims to resolve all relevant scales of a turbulent flow for a one-dimensional domain. Here ODT is applied to turbulent channel flow as stand-alone tool. The ODT domain is a wall-normal line that is aligned with the mean shear. The free model parameters are calibrated once for the turbulent velocity boundary layer at a fixed Reynolds number. After that, we use ODT to investigate …
Large-Scale Reality Modeling Of A University Campus Using Combined Uav And Terrestrial Photogrammetry For Historical Preservation And Practical Use, Bryce Berrett, Cory Vernon, Haley Beckstrand, Madi Pollei, Kaleb Markert, Kevin Franke, John Hedengren
Large-Scale Reality Modeling Of A University Campus Using Combined Uav And Terrestrial Photogrammetry For Historical Preservation And Practical Use, Bryce Berrett, Cory Vernon, Haley Beckstrand, Madi Pollei, Kaleb Markert, Kevin Franke, John Hedengren
Faculty Publications
Unmanned aerial vehicles (UAV) enable detailed historical preservation of large-scale infrastructure and contribute to cultural heritage preservation, improved maintenance, public relations, and development planning. Aerial and terrestrial photo data coupled with high accuracy GPS create hyper-realistic mesh and texture models, high resolution point clouds, orthophotos, and digital elevation models (DEMs) that preserve a snapshot of history. A case study is presented of the development of a hyper-realistic 3D model that spans the complex 1.7 km2 area of the Brigham Young University campus in Provo, Utah, USA and includes over 75 significant structures. The model leverages photos obtained during the historic …
A Reduced-Order Lumped Model For Li-Ion Battery Packs During Operation, Paul T. Coman, Eric C. Darcy, Brad Strangways, Ralph E. White
A Reduced-Order Lumped Model For Li-Ion Battery Packs During Operation, Paul T. Coman, Eric C. Darcy, Brad Strangways, Ralph E. White
Faculty Publications
Modeling heat distribution in Li-ion battery packs can be challenging, especially if the battery pack is large and the cells are operated at high C-rates, which usually requires high-order physics-based mathematical models. Reduced and simplifying models can, however, be used at lower rates. This paper presents a fast novel reduced lumped model (RLM) that can be used to calculate the temperature increase during the high-current discharge of cylindrical Li-ion cells in a subscale of a battery pack. By reducing the PDE utilized to calculate the state of charge (SoC) to ODE's and solving them analytically, the reduced model can be …
Towards Detection Of Sars-Cov-2 Rna In Human Saliva: A Paper-Based Cell-Free Toehold Switch Biosensor With A Visual Bioluminescent Output, J. Porter Hunt, Emily Long Zhao, Tyler J. Free, Mehran Soltani, Chandler A. Warr, Alex B. Benedict, Melissa K. Takahashi, Joel S. Griffitts, William G. Pitt, Bradley C. Bundy
Towards Detection Of Sars-Cov-2 Rna In Human Saliva: A Paper-Based Cell-Free Toehold Switch Biosensor With A Visual Bioluminescent Output, J. Porter Hunt, Emily Long Zhao, Tyler J. Free, Mehran Soltani, Chandler A. Warr, Alex B. Benedict, Melissa K. Takahashi, Joel S. Griffitts, William G. Pitt, Bradley C. Bundy
Faculty Publications
The COVID-19 pandemic has illustrated the global demand for rapid, low-cost, widely distributable and point-of-care nucleic acid diagnostic technologies. Such technologies could help disrupt transmission, sustain economies and preserve health and lives during widespread infection. In contrast, conventional nucleic acid diagnostic procedures require trained personnel, complex laboratories, expensive equipment, and protracted processing times. In this work, lyophilized cell-free protein synthesis (CFPS) and toehold switch riboregulators are employed to develop a promising paper-based nucleic acid diagnostic platform activated simply by the addition of saliva. First, to facilitate distribution and deployment, an economical paper support matrix is identified and a mass-producible test …
Investigating Influence Of Geometry And Operating Conditions On Local Current, Concentration, And Crossover In Alkaline Water Electrolysis Using Computational Fluid Dynamics, J. S. Lopata, S-G. Kang, H-S. Cho, C-H. Kim, J. W. Weidner, Sirivatch Shimpalee
Investigating Influence Of Geometry And Operating Conditions On Local Current, Concentration, And Crossover In Alkaline Water Electrolysis Using Computational Fluid Dynamics, J. S. Lopata, S-G. Kang, H-S. Cho, C-H. Kim, J. W. Weidner, Sirivatch Shimpalee
Faculty Publications
We use a three-dimensional computational fluid dynamics model to examine the liquid saturation, KOH concentration, and gas crossover in an alkaline diaphragm water electrolysis device. The effects of cell potential, solution feed rate, and aspects of the design such as the locations and widths of channels on performance and crossover were studied. The results build a case for implementing a separator transport model and an electrode/separator interface model because of the concentration changes observed at the anode and cathode. Simulations suggest a strong relationship between solution feed rate and the nature of dissolved gas crossover through the diaphragm due to …
Dynamic Simulation Of A Novel Nuclear Hybrid Energy System With Large-Scale Hydrogen Storage In An Underground Salt Cavern, An Ho, Kasra Mohammadi, Matthew Memmott, John Hedengren, Kody Powell
Dynamic Simulation Of A Novel Nuclear Hybrid Energy System With Large-Scale Hydrogen Storage In An Underground Salt Cavern, An Ho, Kasra Mohammadi, Matthew Memmott, John Hedengren, Kody Powell
Faculty Publications
In this study, a nuclear hybrid energy system (NHES) with large-scale hydrogen storage integrated with a gas turbine cycle is proposed as a flexible system for load following. The proposed system consists of a nuclear reactor, a steam Rankine cycle, a hydrogen electrolyzer, a storage system for hydrogen in an underground salt cavern, and a Brayton cycle that uses hydrogen as fuel to generate additional electricity to meet peak demand. A dynamic mathematical model is developed for each subsystem of the NHES. To evaluate the potential benefits of the system, a one-year study is conducted, using scaled grid demand data …
Electroanalytical Measurements Of Oxide Ions In Molten Cacl2 On W Electrode, Devin Rappleye, Chao Zhang, Art Nelson, Scott Simpson, Michael Simpson
Electroanalytical Measurements Of Oxide Ions In Molten Cacl2 On W Electrode, Devin Rappleye, Chao Zhang, Art Nelson, Scott Simpson, Michael Simpson
Faculty Publications
The electrochemical interaction of oxide ions with tungsten electrodes in molten calcium chloride (CaCl2) was analyzed by combining electroanalytical techniques with X-ray photoelectron spectroscopy. During a cyclic voltammetry (CV) scan, the oxide ions appear to interact with the tungsten working electrode via a multi-step oxidation and reduction process. The overall redox peaks behave reversibly up to 750 mV/s. This electrochemical process enables the oxide ion concentration to be correlated to CV oxidation peaks. The resulting correlation agrees well (8.8% difference) with back titration measurements and can be used to monitor oxide content in the salt in real-time during …
Merging Of Horizontally And Vertically Separated Small-Scale Buoyant Flames, Thomas H. Fletcher, Denver Haycock, Seth Tollefsen, David Lignell
Merging Of Horizontally And Vertically Separated Small-Scale Buoyant Flames, Thomas H. Fletcher, Denver Haycock, Seth Tollefsen, David Lignell
Faculty Publications
The purpose of this study was to investigate the merging behavior of small-scale buoyant flames that might be representative of flames from a leaf in a shrub. Zirconia felt pads soaked in n-heptane were suspended on thin rods and spaced both horizontally and vertically. Time-dependent video images from flames from two-pad and three-pad configurations were analyzed to determine merging probability, combined flame characteristics (height, area, and width), and changes in burn time. Correlations of these combined flame characteristics were developed based on horizontal and vertical spacing between the pads. Merging probability correlated with an exponential function that was quadratic in …
Electrochemical Micro-Aptasensors For Exosome Detection Based On Hybridization Chain Reaction Amplification, Wenfen Zhang, Zhenhua Tian, Shujie Yang, Joseph Rich, Shuaiguo Zhao, Mikael Klingeborn, Po-Hsun Huang, Zhishang Li, Alexander Stout, Quinn Murphy, Edward Patz, Shusheng Zhang, Guozhen Liu, Tony Jun Huang
Electrochemical Micro-Aptasensors For Exosome Detection Based On Hybridization Chain Reaction Amplification, Wenfen Zhang, Zhenhua Tian, Shujie Yang, Joseph Rich, Shuaiguo Zhao, Mikael Klingeborn, Po-Hsun Huang, Zhishang Li, Alexander Stout, Quinn Murphy, Edward Patz, Shusheng Zhang, Guozhen Liu, Tony Jun Huang
Faculty Publications
Exosomes are cell-derived nanovesicles that have recently gained popularity as potential biomarkers in liquid biopsies due to the large amounts of molecular cargo they carry, such as nucleic acids and proteins. However, most existing exosome-based analytical sensing methods struggle to achieve high sensitivity and high selectivity simultaneously. In this work, we present an electrochemical micro-aptasensor for the highly sensitive detection of exosomes by integrating a micropatterned electrochemical aptasensor and a hybridization chain reaction (HCR) signal amplification method. Specifically, exosomes are enriched on CD63 aptamer-functionalized electrodes and then recognized by HCR products with avidin-horseradish peroxidase (HRP) attached using EpCAM aptamers as …
Rapid Computation Of Effective Conductivity Of 2d Composites By Equivalent Circuit And Spectral Methods., Ben J. Ransom, Dean R. Wheeler
Rapid Computation Of Effective Conductivity Of 2d Composites By Equivalent Circuit And Spectral Methods., Ben J. Ransom, Dean R. Wheeler
Faculty Publications
This work presents models for homogenizing or finding the effective transport or mechanical properties of microscale composites formed from highly contrasting phases described on a grid. The methods developed here are intended for engineering applications where speed and geometrical flexibility are a premium. A canonical case that is mathematically challenging and yet can be applied to many realistic materials is a 4-phase 2-dimensional periodic checkerboard or tiling. While analytic solutions for calculating effective properties exist for some cases, versatile methods are needed to handle anisotropic and non-square grids. A reinterpretation and extension of an existing analytic solution that utilizes equivalent …
The Effects Of Ceria Loading On Three-Way Catalysts For Passive Scr Operation, Calvin R. Thomas, Josh A. Pihl, Vitaly Y. Prikhodko, Michelle K. Kidder, Jochen A. Lauterbach, Todd J. Toops
The Effects Of Ceria Loading On Three-Way Catalysts For Passive Scr Operation, Calvin R. Thomas, Josh A. Pihl, Vitaly Y. Prikhodko, Michelle K. Kidder, Jochen A. Lauterbach, Todd J. Toops
Faculty Publications
Passive SCR systems, which employ both a three-way catalyst and SCR catalyst, are effective for the reduction of nitrogen oxide (NOx) emissions from lean burn gasoline engines. However, questions remain regarding the effect of three-way catalyst formulations on their performance in these systems. Here, Pd/CeOx/Al2O3 catalysts with variable CeOx loading were synthesized, characterized, and evaluated to determine the effects of CeOx on catalyst performance. While a small amount of ceria was beneficial for promoting essential reactions, excess ceria was detrimental due to the increase in oxygen storage capacity. Additionally, insights into potential reaction pathways for NH3 production were determined.
The Effects Of Ceria Loading On Three-Way Catalysts For Passive Scr Operation, Calvin R. Thomas, Josh A. Pihl, Vitaly Y. Prikhodko, Michelle K. Kidder, Jochen A. Lauterbach, Todd J. Toops
The Effects Of Ceria Loading On Three-Way Catalysts For Passive Scr Operation, Calvin R. Thomas, Josh A. Pihl, Vitaly Y. Prikhodko, Michelle K. Kidder, Jochen A. Lauterbach, Todd J. Toops
Faculty Publications
Passive SCR systems, which employ both a three-way catalyst and SCR catalyst, are effective for the reduction of nitrogen oxide (NOx) emissions from lean burn gasoline engines. However, questions remain regarding the effect of three-way catalyst formulations on their performance in these systems. Here, Pd/CeOx/Al2O3 catalysts with variable CeOx loading were synthesized, characterized, and evaluated to determine the effects of CeOx on catalyst performance. While a small amount of ceria was beneficial for promoting essential reactions, excess ceria was detrimental due to the increase in oxygen storage capacity. Additionally, insights into potential reaction pathways for NH3 production were determined.
Mixing Optimization With Inward Flow Configuration Contra-Rotating Impeller, Baffle-Free Tank, P. Satjaritanun, J. R. Regalbuto, J. A. Regalbuto, N. Tippayawong, Sirivatch Shimpalee
Mixing Optimization With Inward Flow Configuration Contra-Rotating Impeller, Baffle-Free Tank, P. Satjaritanun, J. R. Regalbuto, J. A. Regalbuto, N. Tippayawong, Sirivatch Shimpalee
Faculty Publications
In this study, pitched-blade, contra-rotating impeller, baffle-free tank with opposing inward flow is optimized using various designs of mixers derived from the Taguchi method. Mixing efficiency and torque are used to find the optimal design for the different specific gravities of solid particles employing in both experiments and CFD simulations. The analysis of signal-to-noise ratio shows that the impeller clearance and diameter are significant factors on the fluid flow and thus the mixing efficiency. In this study, 27 cases were studied to determine and report the optimal design parameters. A combination of CFD simulation with a strong design of experiment …
Production Of Pure Vanadium: Industry Review And Feasibility Study Of Electron Beam Melt Refining Of V–Al Alloys, Devin Rappleye, Rob Haun
Production Of Pure Vanadium: Industry Review And Feasibility Study Of Electron Beam Melt Refining Of V–Al Alloys, Devin Rappleye, Rob Haun
Faculty Publications
The vanadium industry has experienced significant change over the last two decades with the emergence of vanadium redox flow batteries for grid-level energy storage, the growing demand for high-strength steel, and the selection of vanadium as a critical material in multiple countries. This review presents the status of the vanadium industry examining production processes and detailing facilities. The available information for each producer is presented including vanadium products and capacity. The production of pure vanadium is identified as a potential vulnerability for some nations where vanadium metal is needed in small, yet strategic, applications and globally only two producers of …
The Impact Of Micro Porous Layer On Liquid Water Evolution Inside Pemfc Using Lattice Boltzmann Method, Mitchell Sepe, P. Satjaritanun, I. V. Zenyuk, N. Tippayawong, Sirivatch Shimpalee
The Impact Of Micro Porous Layer On Liquid Water Evolution Inside Pemfc Using Lattice Boltzmann Method, Mitchell Sepe, P. Satjaritanun, I. V. Zenyuk, N. Tippayawong, Sirivatch Shimpalee
Faculty Publications
Proton exchange membrane fuel cells (PEMFCs) require a gas diffusion layer to aid in fuel transport to the catalyst sites. A microporous layer (MPL) is often added to the GDL to improve liquid saturation inside gas diffusion media. In this work, the lattice Boltzmann method was applied to four GDL samples with the addition of an MPL. Three injection orientations were used to study liquid evolution through the samples. Each orientation used four different injection pressures, ranging from 5,000 Pa to 8,000 Pa. Saturation data for GDL samples with and without an MPL were compared. Results showed that when adding …
Nanoparticles For Targeted Drug Delivery To Cancer Stem Cells: A Review Of Recent Advances, Yavuz Nuri Ertas, Keyvan Abedu Dorcheh, Ali Akbari, Esmaiel Jabbari
Nanoparticles For Targeted Drug Delivery To Cancer Stem Cells: A Review Of Recent Advances, Yavuz Nuri Ertas, Keyvan Abedu Dorcheh, Ali Akbari, Esmaiel Jabbari
Faculty Publications
Cancer stem cells (CSCs) are a subpopulation of cells that can initiate, self-renew, and sustain tumor growth. CSCs are responsible for tumor metastasis, recurrence, and drug resistance in cancer therapy. CSCs reside within a niche maintained by multiple unique factors in the microenvironment. These factors include hypoxia, excessive levels of angiogenesis, a change of mitochondrial activity from aerobic aspiration to aerobic glycolysis, an upregulated expression of CSC biomarkers and stem cell signaling, and an elevated synthesis of the cytochromes P450 family of enzymes responsible for drug clearance. Antibodies and ligands targeting the unique factors that maintain the niche are utilized …
Application Of Compositional Data Analysis To Determine The Effects Of Heating Mode, Moisture Status And Plant Species On Pyrolysates, David R. Weise, Thomas H. Fletcher, Mohammad-Saeed Safdari, Elham Amini, Javier Palarea-Albaladejo
Application Of Compositional Data Analysis To Determine The Effects Of Heating Mode, Moisture Status And Plant Species On Pyrolysates, David R. Weise, Thomas H. Fletcher, Mohammad-Saeed Safdari, Elham Amini, Javier Palarea-Albaladejo
Faculty Publications
Pyrolysate gas mixtures are multivariate and relative in nature. Statistical techniques applied to these data generally ignore their relative nature. Published data for permanent gases (CO, CO2, H2, CH4) and tars produced by pyrolysing 15 wildland fuels were reanalysed using compositional data analysis techniques. Mass and mole fractions were compositionally equivalent. Plant species, moisture status and heating mode effects on compositional balances formed from subsets of pyrolysates were tested. Plant species affected the amount of phenol, primary and secondary/tertiary tars relative to permanent gases and relative amounts of single- and multi-ring compounds. Plant moisture status affected the amount of CO …
Resolving Anodic Current And Temperature Distributions In A Polymer Electrolyte Membrane Water Electrolysis Cell Using A Pseudo-Two-Phase Computational Fluid Dynamics Model, J. Lopata, Z. Kang, J. Young, G. Bender, J. W. Weidner, H-S. Cho, Sirivatch Shimpalee
Resolving Anodic Current And Temperature Distributions In A Polymer Electrolyte Membrane Water Electrolysis Cell Using A Pseudo-Two-Phase Computational Fluid Dynamics Model, J. Lopata, Z. Kang, J. Young, G. Bender, J. W. Weidner, H-S. Cho, Sirivatch Shimpalee
Faculty Publications
Expanding upon our prior experimental work, we constructed a three-dimensional model of a polymer electrolyte membrane water electrolyzer using computational fluid dynamics. We applied the assumption of pseudo-two-phase flow, the flow of two phases with equal velocity. Experimental data were used to obtain parameters and to determine the conditions under which this model was valid. Anodic distributions of current density, temperature, liquid saturation, and relative humidity were obtained at various flow rates. The overall current density and temperature difference from inlet to outlet at the anode agreed strongly with experimental measurements under most circumstances. This verification allowed us to further …
Pyrolysis Kinetics Of Wildland Vegetation Using Model-Fitting Methods, Ellie Amini, Mohammad-Saeed Safdari, Nathan Johnson Brigham, David R. Weise, Thomas H. Fletcher
Pyrolysis Kinetics Of Wildland Vegetation Using Model-Fitting Methods, Ellie Amini, Mohammad-Saeed Safdari, Nathan Johnson Brigham, David R. Weise, Thomas H. Fletcher
Faculty Publications
Slow-heating pyrolysis experiments of 14 plant species native to forests in the southern United States were conducted in a TGA to find the kinetic parameters for slow pyrolysis of all live and air-dried plant samples. Kinetic coefficients were determined from the data using model-fitting methods, resulting in single kinetic parameters for the entire pyrolysis process which can be used by wildland fire modelers. The model forms explored here are a simple one-step model and single and multiple reaction distributed activation energy (DAE) models. The mass loss and derivative mass loss data were fitted simultaneously at heating rates of 10, 20, …
Editors’ Choice-Examining Performance And Durability Of Anion Exchange Membrane Fuel Cells With Novel Spirocyclic Anion Exchange Membranes, Ami C. Yang-Neyerlin, Samantha Medina, Kelly M. Meek, Derek J. Strasser, Cheng He, Daniel M. Knauss, Mustain E William, Svitlana Pylypenko, Bryan S. Pivovar
Editors’ Choice-Examining Performance And Durability Of Anion Exchange Membrane Fuel Cells With Novel Spirocyclic Anion Exchange Membranes, Ami C. Yang-Neyerlin, Samantha Medina, Kelly M. Meek, Derek J. Strasser, Cheng He, Daniel M. Knauss, Mustain E William, Svitlana Pylypenko, Bryan S. Pivovar
Faculty Publications
A series of spirocyclic copolymer membranes with varying ion exchange capacities (IECs) were investigated to probe the impact of polymer properties on in situ fuel cell performance and stability. In-situ electrochemical tests and post-mortem electron microscopy analysis of cross-sectioned membrane electrode assemblies (MEAs) have been combined with voltage loss breakdown analysis to evaluate the performance and degradation of different MEAs, and to probe the catalyst morphology and electrode structure at different stages of operation. Voltage loss breakdown results show that membrane degradation and kinetic losses played only a minor role in observed performance degradation and that performance losses were primarily …
Hybrid Lattice Boltzmann Agglomeration Method For Modeling Transport Phenomena In Polymer Electrolyte Membrane Fuel Cells, P. Satjaritanun, F. C. Cetinbas, S. Hirano, I. V. Zenyuk, R. K. Ahluwalia, Sirivatch Shimpalee
Hybrid Lattice Boltzmann Agglomeration Method For Modeling Transport Phenomena In Polymer Electrolyte Membrane Fuel Cells, P. Satjaritanun, F. C. Cetinbas, S. Hirano, I. V. Zenyuk, R. K. Ahluwalia, Sirivatch Shimpalee
Faculty Publications
The Hybrid Lattice Boltzmann Agglomeration Method (HLBAM) was employed to model transport phenomena and electrochemical kinetics in the catalyst layer of a polymer electrolyte membrane fuel cell (PEMFC). This work showed the advantages of using a direct modeling-based HLBAM approach, which incorporates the detailed structure of catalyst layers from X-ray computed tomography as well as local transport variables related characteristics and effective properties from the hybrid catalyst microstructure. The local transport variables and effective properties from the hybrid catalyst model were used to simulate the electrochemical kinetics inside the detailed structure of the catalyst layer. HLBAM can predict the distribution …
Hydrothermal Synthesis And Structural Investigation Of A Crystalline Uranyl Borosilicate, Kristen A. Pace, Vladislav V. Klepov, Mark D. Smith, Travis Williams, Gregory Morrison, Jochen A. Lauterbach, Scott T. Misture, Hans Conrad Zur Loye
Hydrothermal Synthesis And Structural Investigation Of A Crystalline Uranyl Borosilicate, Kristen A. Pace, Vladislav V. Klepov, Mark D. Smith, Travis Williams, Gregory Morrison, Jochen A. Lauterbach, Scott T. Misture, Hans Conrad Zur Loye
Faculty Publications
The relevance of multidimensional and porous crystalline materials to nuclear waste reme-diation and storage applications has motivated exploratory research focused on materials discovery of compounds, such as actinide mixed-oxoanion phases, which exhibit rich structural chemistry. The novel phase K1.8 Na1.2 [(UO2)BSi4 O12 ] has been synthesized using hydrothermal methods, rep-resenting the first example of a uranyl borosilicate. The three-dimensional structure crystallizes in the orthorhombic space group Cmce with lattice parameters a = 15.5471(19) Å, b = 14.3403(17) Å, c = 11.7315(15) Å, and V = 2615.5(6) Å3, and is composed of UO6 octahedra linked by [BSi4 O12 ]5− chains to …
Hydrothermal Synthesis And Structural Investigation Of A Crystalline Uranyl Borosilicate, Kristen A. Pace, Vladislav V. Klepov, Mark D. Smith, Travis Williams, Gregory Morrison, Jochen A. Lauterbach, Scott T. Misture, Hans Conrad Zur Loye
Hydrothermal Synthesis And Structural Investigation Of A Crystalline Uranyl Borosilicate, Kristen A. Pace, Vladislav V. Klepov, Mark D. Smith, Travis Williams, Gregory Morrison, Jochen A. Lauterbach, Scott T. Misture, Hans Conrad Zur Loye
Faculty Publications
The relevance of multidimensional and porous crystalline materials to nuclear waste reme-diation and storage applications has motivated exploratory research focused on materials discovery of compounds, such as actinide mixed-oxoanion phases, which exhibit rich structural chemistry. The novel phase K1.8 Na1.2 [(UO2)BSi4 O12 ] has been synthesized using hydrothermal methods, rep-resenting the first example of a uranyl borosilicate. The three-dimensional structure crystallizes in the orthorhombic space group Cmce with lattice parameters a = 15.5471(19) Å, b = 14.3403(17) Å, c = 11.7315(15) Å, and V = 2615.5(6) Å3, and is composed of UO6 octahedra linked by [BSi4 O12 ]5− chains to …
Development Of Small-Scale Plutonium Electrorefining In Molten Cacl2, Devin Rappleye, James Mcneese, Richard Torres, Kiel Holliday, Jason R. Jeffries
Development Of Small-Scale Plutonium Electrorefining In Molten Cacl2, Devin Rappleye, James Mcneese, Richard Torres, Kiel Holliday, Jason R. Jeffries
Faculty Publications
Molten salt extraction and electrorefining of plutonium were successfully conducted with only a 200-g initial charge. Due to this small scale, the electrorefining cell components were redesigned relative to conventional, multi-kg standards. The efficiency and yield of this small-scale process are comparable to those of larger-scale exemplars. Chemical analysis of the plutonium product and the anode heel is presented. The product was 99.8% pure. The anode heel was able to be depleted beyond the expected freezing point without significant impurity carryover.