Chemical Engineering Commons^™

Marangoni Flows During Nonsolvent Induced Phase Separation, Douglas R. Tree, Tatsuhiro Iwama, Kris T. Delaney, Joshua Lee, Glenn H. Fredrickson

Faculty Publications

Motivated by the much discussed, yet unexplained, presence of macrovoids in polymer membranes, we explore the impact of Marangoni flows in the process of nonsolvent induced phase separation. Such flows have been hypothesized to be important to the formation of macrovoids, but little quantitative evidence has been produced to date. Using a recently developed multifluid phase field model, we find that roll cells indicative of a solutal Marangoni instability are manifest during solvent/nonsolvent exchange across a stable interface. However, these flows are weak and subsequently do not produce morphological features that might lead to macrovoid formation. By contrast, initial conditions …

Nanoreactors: Strategies To Encapsulate Enzyme Biocatalysts In Virus-Like Particles, Joshua W. Wilkerson, Seung-Ook Yang, Parker J. Funk, Steven K. Stanley, Bradley Charles Bundy

Faculty Publications

Enzyme-mediated biocatalysis is generally more selective and environmentally friendly and requires less energy than chemocatalysis. However, factors such as temperature, acidity and the presence of proteases can negate enzyme activity. Encapsulation in virus-like particles is one promising method to mitigate these difficulties. Encapsulation also can be used to create multi-reaction nanoreactors that increase process efficiency by isolating reaction intermediates. To successfully encapsulate enzymes, a variety of methods involving both non-covalent and covalent interactions have been developed. Here we review promising virus-like particle encapsulation strategies, their advantages and remaining challenges.

Lyophilized Escherichia Coli-Based Cell-Free Systems For Robust, High-Density, Long-Term Storage, Mark Thomas Smith, Scott D. Berkheimer, Christopher J. Werner, Bradley Charles Bundy

Faculty Publications

Cell-free protein synthesis (CFPS) is a versatile tool for rapid recombinant protein production and engineering. One drawback of cell-free technology is the necessity to store the major components—cell extracts and energy systems—below freezing in bulky aqueous solutions. Here we describe simple methods for lyophilizing extracts and preparing powdered energy systems for CFPS. These techniques allow for high-density storage of cell-free systems that are more robust against temperature and bacterial degradation. Our methods have the potential to decrease storage expenses, allow for longer shelf-life of cell extracts at room temperature, and enable durable portable protein production technologies.

Streamlined Extract Preparation For Escherichia Coli-Based Cell-Free Protein Synthesis By Sonication Or Bead Vortex Mixing, Prashanta Shrestha, Troy Michael Holland, Bradley Charles Bundy

Faculty Publications

Escherichia coli-based cell extract is a vital component of inexpensive and high-yielding cell-free protein synthesis reactions. However, effective preparation of E. coli cell extract is limited to high-pressure (French press-style or impinge-style) or bead mill homogenizers, which all require a significant capital investment. Here we report the viability of E. coli cell extract prepared using equipment that is both common to biotechnology laboratories and able to process small volume samples. Specifically, we assessed the low-capital-cost lysis techniques of: (i) sonication, (ii) bead vortex mixing, (iii) freeze-thaw cycling, and (iv) lysozyme …

New Flow Assurance System With High Speed Subsea Fiber Optic Monitoring Of Pressure And Temperature, John Hedengren, David Brower, J. Conrad Wilson, Geoff High, Karl Witherow

Faculty Publications

Subsea production control systems are instrumented to constantly monitor flowline pressure and temperature at key locations to prevent plugging and introduce mitigating control strategies. New fiber optic sensors with ruggedized construction and non-electrical components are subjected to accelerated aging tests and deployed in several installations with long service life. An overview of current progress with fiber optic technology is provided for fatigue monitoring, temperature, pressure, and strain sensing. Recent developments include improved service life, novel bonding methods, pipeline sensor station improvements, sensor calibration, and long-term fatigue analysis.

The latest advancements are validated on multiple installations on a subsea tieback in …

Special Issue: Combined Scheduling And Control, John Hedengren, Logan Beal

Faculty Publications

This Special Issue (SI) of Processes, “Combined Scheduling and Control,” includes approaches to formulating combined objective functions, multi-scale approaches to integration, mixed discrete and continuous formulations, estimation of uncertain control and scheduling states, mixed integer and nonlinear programming advances, benchmark development, comparison of centralized and decentralized methods, and software that facilitates the creation of new applications and long-term sustainment of benefits. Contributions acknowledge strengths, weaknesses, and potential further advancements, along with a demonstration of improvement over current industrial best-practice.

In Situ Uv-Visible Assessment Of Iron-Based High-Temperature Water-Gas Shift Catalysts Promoted With Lanthana: An Extent Of Reduction Study, Basseem B. Hallac, Jared C. Brown, Eli Stavitski, Roger G. Harrison, Morris D. Argyle

Faculty Publications

The extent of reduction of unsupported iron-based high-temperature water-gas shift catalysts with small (< 5 wt %) lanthana contents was studied using UV-visible spectroscopy. Temperature- programmed reduction measurements showed that lanthana content higher than 0.5 wt % increased the extent of reduction to metallic Fe, while 0.5 wt % of lanthana facilitated the reduction to Fe₃O₄. In situ measurements on the iron oxide catalysts using mass and UV-visible spectroscopies permitted the quantification of the extent of reduction under temperature-programmed reduction and high-temperature water-gas shift conditions. The oxidation states were successfully calibrated against normalized absorbance spectra of visible light using the Kubelka-Munk theory. The normalized absorbance relative to the fully oxidized Fe₂O₃ increased as the extent of reduction increased. XANES suggested that the average bulk iron oxidation state during the water-gas shift reaction was Fe^{+2.57 …}

Characterization Of Pyrolysis Products From Fast Pyrolysis Of Live And Dead Vegetation Native To The Southern United States, Mohammad-Saeed Safdari, Mahmood Rahmati, Elham Amini, Joel E. Howarth, Jansen P. Berryhill, Mark Dietenberger, David R. Weise, Thomas H. Fletcher

Faculty Publications

Prescribed burning (controlled burning) is used to decrease accumulation of combustible materials and reduce impact of uncontrolled wildland fires. Prescribed fires are often used to burn undergrowth in Southern forests of the United States. In order to improve prescribed fire application, accomplish desired fire effects, and limit potential runaway fires, an improved understanding of the fundamental processes related to combustion of heterogeneous fuel beds of live and dead fuels is needed. The initial processes of combustion involve pyrolysis and ignition. During this research, fast pyrolysis of 14 live and dead (biomass) plant species which are native to the Southern United …

Effects Of Ag Promotion And Preparation Method On Cobalt Fischer- Tropsch Catalysts Supported On Silica-Modified Alumina, Mahmood Rahmati, Baiyu Huang, Landon M. Schofield, Thomas H. Fletcher, Brian F. Woodfield, William C. Hecker, Calvin H. Bartholomew, Morris D. Argyle

Faculty Publications

A series of silver-promoted, 20 wt% cobalt Fischer-Tropsch synthesis (FTS) catalysts supported on an alumina modified with 5 wt% silica were prepared using two methods: traditional incipient wetness impregnation (IWI) and a new solvent deficient precipitation (SDP) technique. Catalysts containing silver promoter concentrations of 0.3, 0.6, 1.2, and 2.5 wt% were prepared using each of the two methods. Silver improved the reducibility of the cobalt significantly, lowering reduction temperatures by up to 100 C, and increasing the extent of reduction by up to 35%. Further, in both preparation methods, changing the silver loading altered the cobalt dispersion. The smallest Co …

Fire Behavior In Chaparral–Evaluating Flame Models With Laboratory Data, David R. Weise, Thomas H. Fletcher, Wesley Cole, Shankar Mahalingam, Xiangyang Zhou, Lulu Sun, Jing Li

Faculty Publications

Flame and mass loss data for chaparral, a mixture of shrub plants from the Mediterranean climate zone of southwestern North America, from five previously reported experiments were used to evaluate several published models relating flame characteristics to mass loss and heat release rates. These data are unique with fuel moisture content ranging from 0.36 to 0.94 (dry basis); the study used mass loss rates which included water loss. Fit of the data to Froude number correlations developed by Albini, Byram, Nelson and Thomas and heat release rate—flame length correlations by Heskestad, Zukoski, and Yuan/Cox for axisymmetric and line fires were …

Lab-Scale Observations Of Flame Attachment On Slopes With Implications For Firefighter Safety Zones, Jonathan R. Gallacher, Brad Ripa, Bret W. Butler, Thomas H. Fletcher

Faculty Publications

The Coanda effect is the phenomenon in which a jet entering quiescent fluid attaches to a nearby solid object due to inhibited entrainment of ambient fluid near the solid. Little is known about the influence of the Coanda effect on wildland fire behavior. Specifically, there is a lack of knowledge regarding how the flame attachment on slopes influences firefighter safety zone considerations in rugged terrain. This paper presents results for small-scale n-heptane pool fire experiments near a slope, showing how flame shape and heat flux are influenced by slope angle, slope boundary condition and distance from flame base. Flames near …

Development Of Bioreactors For Comparative Study Of Naturalattenuation, Biostimulation, And Bioaugmentation Ofpetroleum-Hydrocarbon Contaminated Soil, Mohammad-Saeed Safdari, Hamid-Reza Kariminia, Mahmood Rahmati, Farhad Fazlollahi, Alexandra Polasko, Shaily Mahendra, W Vincent Wilding, Thomas H. Fletcher

Faculty Publications

Bioremediation of soil and groundwater sites contaminated by petroleum hydrocarbons is known as a technically viable, cost-effective, and environmentally sustainable technology. The purpose of this study is to investigate laboratory-scale bioremediation of petroleum-hydrocarbon contaminated soil through development of eight bioreactors, two bioreactors for each bioremediation mode. The modes were: (1)natural attenuation (NA); (2) biostimulation (BS) with oxygen and nutrients; (3) bioaugmentation (BA)with hydrocarbon degrading isolates; (4) a combination of biostimulation and bioaugmentation (BS-BA). Total petroleum hydrocarbons (TPH) mass balance over the bioreactors showed about 2% of initial20,000 mg kg-soil−1TPH was removed by advection due to synthetic groundwater which was flow-ing …

Formation Of Deposits From Heavy Fuel Oil Ash In An Accelerated Deposition Facility At Temperatures Up To 1219 °C, Robert Laycock, Thomas H. Fletcher

Faculty Publications

Some industrial gas turbines are currently being fired using heavy fuel oil, which contains a small percentage of inorganic material that can lead to fouling and corrosion of turbine components. Deposits of heavy fuel oil ash were created in the Turbine Accelerated Deposition Facility (TADF) at Brigham Young University under gas turbine-related conditions. Ash was produced by burning heavy fuel oil in a downward-fired combustor and collecting the ash from the exhaust stream. This ash was then introduced into the TADF and entrained in a hot gas flow that varied from 1101 °C to 1219 °C. Sulfur dioxide was introduced …

A Novel Supercritical Co2-Based Decellularization Method For Maintaining Scaffold Hydration And Mechanical Properties, Michael A. Matthews, Tarek Shazly, Rachel M. Handleton, Dominic M. Casali

Faculty Publications

Decellularized tissues are commonly utilized as tissue engineering scaffolds. Decellularization by extended exposure to aqueous detergents can damage the microstructure or deposit cytotoxic residue. Supercritical carbon dioxide (scCO2) has been proposed for decellularization, but reportedly causes dehydration and scaffold embrittlement.

Presented herein is a novel decellularization method that preserves matrix hydration state and mechanical properties. Over 97% of the water in porcine aorta is maintained by presaturating scCO2 with water; however, complete decellularization was not attained by any process utilizing only scCO2. Instead, a novel hybrid method is presented that combines a brief (48 h) exposure of tissue to aqueous …

Effect Of Different Alumina Supports On Performance Of Cobalt Fischer-Tropsch Catalysts, Thomas H. Fletcher

Faculty Publications

Four identically-prepared 20 wt% cobalt/0.15 wt% ruthenium Fischer-Tropsch catalysts, supported on different aluminas, were synthesized by incipient wetness impregnation, characterized, and compared based on their performance under standard Fischer-Tropsch synthesis conditions. Three alumina supports were obtained from commercial sources (Sasol, St. Gobain, and Alfa Aesar), while the fourth was made using a published technique that included 5 wt% silica. The silica-stabilized alumina catalyst produced superior Fischer-Tropsch rates of 49 mmol CO/gcat h, compared to the other catalysts on the commercial supports with rates of 26–39 mmol CO/gcat h. The improved performance of the silica-stabilized alumina support compared to the commercially …

Combined Noncyclic Scheduling And Advanced Control For Continuous Chemical Processes, Damon Petersen, Logan D. R. Beal, Derek Prestwich, Sean Warnick, John Hedengren

Faculty Publications

A novel formulation for combined scheduling and control of multi-product, continuous chemical processes is introduced in which nonlinear model predictive control (NMPC) and noncyclic continuous-time scheduling are efficiently combined. A decomposition into nonlinear programming (NLP) dynamic optimization problems and mixed-integer linear programming (MILP) problems, without iterative alternation, allows for computationally light solution. An iterative method is introduced to determine the number of production slots for a noncyclic schedule during a prediction horizon. A filter method is introduced to reduce the number of MILP problems required. The formulation’s closed-loop performance with both process disturbances and updated market conditions is demonstrated through …

Sexual Recombination And Increased Mutation Rate Expedite Evolution Of Escherichia Coli In Varied Fitness Landscapes, George Peabody, Hao Li, Katy Kao

Faculty Publications

Sexual recombination and mutation rate are theorized to play different roles in adaptive evolution depending on the fitness landscape; however, direct experimental support is limited. Here we examine how these factors affect the rate of adaptation utilizing a “genderless” strain of Escherichia coli capable of continuous in situ sexual recombination. The results show that the populations with increased mutation rate, and capable of sexual recombination, outperform all the other populations. We further characterize two sexual and two asexual populations with increased mutation rate and observe maintenance of beneficial mutations in the sexual populations through mutational sweeps. Furthermore, we experimentally identify …

Combined Model Predictive Control And Scheduling With Dominant Time Constant Compensation, Logan Beal, Junho Park, Damon Petersen, Sean C. Warnick, John Hedengren

Faculty Publications

Linear model predictive control is extended to both control and optimize a product grade schedule. The proposed methods are time-scaling of the linear dynamics based on throughput rates and grade-based objectives for product scheduling based on a mathematical program with complementarity constraints. The linear model is adjusted with a residence time approximation to time-scale the dynamics based on throughput. Although nonlinear models directly account for changing dynamics, the model form is restricted to linear differential equations to enable fast online cycle times for large-scale and real-time systems. This method of extending a linear time-invariant model for scheduling is designed for …

Insights On Osmotic Tolerance Mechanisms In Escherichia Coli Gained From An Rpoc Mutation, Yuqi Guo, James Winkler, Katy Kao

Faculty Publications

An 84 bp in-frame duplication (K370_A396dup) within the rpoC subunit of RNA polymerase was found in two independent mutants selected during an adaptive laboratory evolution experiment under osmotic stress in Escherichia coli, suggesting that this mutation confers improved osmotic tolerance. To determine the role this mutation in rpoC plays in osmotic tolerance, we reconstructed the mutation in BW25113, and found it to confer improved tolerance to hyperosmotic stress. Metabolite analysis, exogenous supplementation assays, and cell membrane damage analysis suggest that the mechanism of improved osmotic tolerance by this rpoC mutation may be related to the higher production of acetic acid …

The Effects Of Tether Placement On Antibody Stability On Surfaces, Thomas A. Knotts, Rebecca W. Grawe

Faculty Publications

Despite their potential benefits, antibody microarrays have fallen short of performing reliably and have not found widespread use outside of the research setting. Experimental techniques have been unable to determine what is occurring on the surface of an atomic level, so molecular simulation has emerged as the primary method of investigating protein/surface interactions. Simulations of small proteins have indicated that the stability of the protein is a function of the residue on the protein where a tether is placed. The purpose of this research is to see whether these findings also apply to antibodies, with their greater size and complexity. …

Continuous Ethanol Production From Synthesis Gas By Clostridium Ragsdalei In A Trickle-Bed Reactor, Mamatha Devarapalli, Randy S. Lewis, Hasan K. Atiyeh

Faculty Publications

A trickle-bed reactor (TBR) when operated in a trickle flow regime reduces liquid resistance to mass transfer because a very thin liquid film is in contact with the gas phase and results in improved gas–liquid mass transfer compared to continuous stirred tank reactors (CSTRs). In the present study, continuous syngas fermentation was performed in a 1-L TBR for ethanol production by Clostridium ragsdalei. The effects of dilution and gas flow rates on product formation, productivity, gas uptakes and conversion efficiencies were examined. Results showed that CO and H2 conversion efficiencies reached over 90% when the gas flow rate was maintained …

Preliminary Study Of Optimization Of Normal Pulse Voltammetry For Actinide Measurement In Molten Salt Electrorefiners Using Licl-Kcl-Ucl3-Mgcl2 As A Surrogate Salt, Chao Zhang, Devin Rappleye, Michael Simpson

Faculty Publications

Normal pulse voltammetry has been applied and optimized to develop correlations between diffusional current and concentration for UCl₃ and MgCl₂ in molten eutectic LiCl-KCl. This method was selected to mitigate working electrode area growth in concentrated molten salt mixtures in which a fairly wide potential range is needed to analyze all actinides. MgCl₂ has been selected as a surrogate for PuCl₃ based on similar standard reduction potential. Diffusional current plateaus were successfully attained by adjusting the step size to 0.03 V. Relaxation time of 15 seconds was found to be sufficient to recover after each pulse. …

Uncertainty Quantification And Propagation Of Errors Of The Lennard-Jones 12-6 Parameters For N-Alkanes, Richard A. Messerly, Thomas A. Knotts Iv, W Vincent Wilding

Faculty Publications

Molecular simulation has the ability to predict various physical properties that are difficult to obtain experimentally. For example, we implement molecular simulation to predict the critical constants (i.e., critical temperature, critical density, critical pressure, and critical compressibility factor) for large n-alkanes that thermally decompose experimentally (as large as C₄₈). Historically, molecular simulation has been viewed as a tool that is limited to providing qualitative insight. One key reason for this perceived weakness in molecular simulation is the difficulty to quantify the uncertainty in the results. This is because molecular simulations have many sources of uncertainty that propagate …

Cytosolic Delivery Of Doxorubicin From Liposomes To Multidrug-Resistant Cancer Cells Via Vaporization Of Perfluorocarbon Droplets, Jacob B. Williams, Clara M. Buchanan, Ghaleb Husseini, William G. Pitt

Faculty Publications

A common mechanism of multidrug resistance is the upregulation of efflux pumps in the cancer cells that can more rapidly export unwanted materials (e.g. cancer drugs) out of the cell, compared to sensitive cancer cells. This research seeks to overcome this mechanism by vaporizing a perfluoropentane emulsion droplet inside of a drug-containing liposome (eLiposome) that was endocytosed into a cancer cell. Folate attached to the eLiposome facilitates uptake into the cell as observed by confocal microscopy. Ultrasound was examined as a trigger to initiate the vaporization of the perfluoropentane droplet and release doxorubicin from folated eLipsosomes (feLD). Two seconds of …

Cytosolic Delivery Of Doxorubicin From Liposomes To Multidrug-Resistant Cancer Cells Via Vaporization Of Perfluorocarbon Droplets, Jacob B. Williams, Clara M. Buchanan, Ghaleb A. Husseini, William G. Pitt

Faculty Publications

A common mechanism of multidrug resistance is the upregulation of efflux pumps in the cancer cells that can more rapidly export unwanted materials (e.g. cancer drugs) out of the cell, compared to sensitive cancer cells. This research seeks to overcome this mechanism by vaporizing a perfluoropentane emulsion droplet inside of a drug-containing liposome (eLiposome) that was endocytosed into a cancer cell. Folate attached to the eLiposome facilitates uptake into the cell as observed by confocal microscopy. Ultrasound was examined as a trigger to initiate the vaporization of the perfluoropentane droplet and release doxorubicin from folated eLiposomes (feLD). Two seconds of …

Potential Benefits Of Combining Anomaly Detection With View Planning For Uav Infrastructure Modeling, R. Abraham Martin, Landen Blackburn, Joshua Pulsipher, Kevin W. Franke, John Hedengren

Faculty Publications

This paper presents a novel method for UAV-based 3D modeling of large infrastructure objects, such as pipelines, canals and levees, that combines anomaly detection with automatic on-board 3D view planning. The study begins by assuming that anomaly detections are possible and focuses on quantifying the potential benefits of the combined method and the view planning algorithm. A simulated canal environment is constructed, and several simulated anomalies are created and marked. The algorithm is used to plan inspection flights for the anomaly locations, and simulated images from the flights are rendered and processed to construct 3D models of the locations of …

Probing The Effects Of Surface Hydrophobicity And Tether Orientation On Antibody-Antigen Binding, Derek B. Bush, Thomas A. Knotts Iv

Faculty Publications

Antibody microarrays have the potential to revolutionize molecular detection for many applications, but their current use is limited by poor reliability, and efforts to change this have not yielded fruitful results. One difficulty which limits the rational engineering of next-generation devices is that little is known, at the molecular level, about the antibody-antigen binding process near solid surfaces. Atomic-level structural information is scant because typical experimental techniques (X-ray crystallography and NMR) cannot be used to image proteins bound to surfaces. To overcome this limitation, this study uses molecular simulation and an advanced, experimentally validated, coarse-grain, protein-surface model to compare fab-lysozyme …

Catalytic Gasification Of A Powder River Basin Coal With Co2 And H2o Mixtures, Zhang Fan, Fan Maohong, Huang Xin, Morris D. Argyle, Zhang Bo, Brian Towler, Zhang Yulong

Faculty Publications

CO₂ capture and utilization caused more and more public attention because of its environmental impact. The objective of this work was to study the catalytic gasification of a sub-bituminous coal from the Powder River Basin (PRB) using a CO₂ and H₂ O mixture as the gasifying agent. Sodium and iron, in the form of inexpensive compounds, were chosen to catalyze the coal gasification. The experiments were conducted between 700 and 900 °C in a fixed-bed laboratory gasifier under the atmospheric pressure. Results show that the added catalysts had an effect on the composition of gas …

A Multi-Fluid Model For Microstructure Formation In Polymer Membranes, Douglas R. Tree, Kris T. Delaney, Hector D. Ceniceros, Tatsuhiro Iwama, Glenn H. Fredrickson

Faculty Publications

We develop a multi-fluid model for a ternary polymer solution using the Rayleighian formalism of Doi and Onuki, and give an efficient pseudo-spectral method for solving both the diffusion and momentum equations that result. Subsequently, we find that the numerical simulation is capable of describing systems at the micron length-scale and easily reaches millisecond time-scales. In addition, we characterize the model thermodynamics and kinetics including the (i) phase behavior, (ii) structure of the interfaces, (iii) mutual diffusion coefficients, (iv) bulk spinodal decomposition kinetics with and without hydrodynamics and (v) spinodal decomposition in the presence of an interface with a non-solvent …

Application Of The Rotating Cylinder Electrode In Molten Licl-Kcl Eutectic Containing Uranium(Iii)- And Magnesium(Ii)-Chloride, Devin Rappleye, Michael F. Simpson

Faculty Publications

The application of the rotating cylinder electrode (RCE) to molten LiCl-KCl eutectic mixtures for electroanalytical measurements is presented. This enabled the measurement of the limiting current which was observed to follow a linear trend with the rotational rate raised to 0.64–0.65 power on average, which closely agrees with existing RCE mass-transfer correlations. This is the first publication of electroanalytical RCE measurements in LiCl-KCl eutectic based molten salt mixtures, to our knowledge. These measurements were made in mixtures of molten LiCl-KCl eutectic containing UCl₃ and MgCl₂. Kinetic parameters were calculated for Mg²⁺ in LiCl-KCl eutectic. The exchange …