Chemical Engineering Commons^™

Porous Hierarchically Ordered Hydrogels Demonstrating Structurally Dependent Mechanical Properties, Elisabeth C. Lloyd, Sujata Dhakal, Shahrouz Amini, Rami Alhasan, Peter Fratzl, Douglas R. Tree, Svetlana Morozova, Robert J. Hickey

Faculty Publications

While hierarchical ordering is a distinctive feature of natural tissues and is directly responsible for their diverse and unique properties, efforts to synthesize biomaterials have primarily focused on using molecular-based approaches with little emphasis on multiscale structure. Here, we report a bottom-up self-assembly process to produce highly porous hydrogel fibers that resemble extracellular matrices both structurally and mechanically. Physically crosslinked nanostructured micelles form the walls of micrometer-sized water-rich pores with preferred orientation along the fiber direction. Low elastic moduli (< 1 kPa), high elasticity (extending by more than 12 times the initial length), non-linear elasticity (e.g., hyperelasticity), and completely reversible extension are derived from unevenly distributed strain between the micrometer-sized pores and the polymer chains, which is reminiscent of cellular solids. Control of the material microstructure and orientation over many orders of magnitude (e.g., nm–μm), while holding the nanostructure constant, reveals how the multiscale structure directly impacts mechanical properties.

Methods For Rotating Electrodes In High-Temperature Molten Salts, Ranon Fuller, Eloise Cluff, Edward Mercado, Carlos Mejia, Devin Rappleye

Faculty Publications

In this paper, we describe and validate a custom apparatus for performing high-speed (250-3,500 rpm) rotating electrode and dilatometer density experiments in molten salts. The reported details can aid in decreasing the difficulty and increasing the quality of such experiments. We discuss the design challenges and the solutions identified. We investigate methods for accurately measuring the solution resistance using electrochemical impedance spectroscopy (EIS), calculating the working electrode area using cyclic voltammetry (CV), and measuring the mass transfer-limited current of rotating electrodes using a series of chronoamperometry (CA) pulses. We further demonstrate the efficacy of our methods in producing accurate results.

In-Situ Density Measurement For Enhanced Electrorefining Material Accountancy, Edward Mercado, Carlos Mejia, Ranon Fuller, Devin Rappleye

Student Works

To further enhance the proliferation resistance of electrorefining (ER) processes, precise and reliable analytical methods are essential for determining the inventory of fissile material. This can be achieved by electrochemically measuring the salt concentration and converting it to mass using its density. However, the density within the refiner is not fixed, and small variations in salt composition can significantly impact its thermophysical properties. While an ideal mixing model provides reasonable density estimates (with errors up to 2-3%), such errors are unacceptable when precise material accountancy of fissile material is crucial. This study developed a methodology to measure density in situ …

Enhancing Mucus Flow And Clearance By Grafting Zwitterionic Hydrogel Films To Luminal Surfaces, Ryan Horne, Caleb Escudero, Morgan Ellerman, C. Allan Guymon, Marlan Hansen

Faculty Publications

Objective

To determine the effects of zwitterionic hydrogel films on mucus contact angles, flow, and stasis with respect to medical polymer surfaces, both flat and tubular.

Methods

A zwitterionic hydrogel thin film was photografted onto medical rubber surfaces and compared against non-zwitterionic hydrogel thin films and untreated surfaces to determine its impact on mucus contact angles, mucus flow on sheets and tubes, and mucus plugging.

Results

Zwitterionic and conventional hydrogel films significantly reduce the mucus contact angles and the tilt required to initiate mucus flow on sheets and in tubular systems. Preliminary experiments show that these films may also shorten …

Uncertainty Propagation And Sensitivity Analysis For Constrained Optimization Of Nuclear Waste Vitrification, Lagrande Gunnell, Xiaonan Lu, John D. Vienna, Dong-Sang Kim, Brian J. Riley, John Hedengren

Faculty Publications

The vitrification of high-level waste (HLW) by heating a mixture of glass-forming chemicals (GFCs) with the waste can be improved using a constrained optimization problem. This study explores how different uncertainty propagation (UP) methods implemented with the optimization process can affect the glass formulation of nuclear waste glasses. UP is the effort of propagating uncertain inputs through a system to understand and quantify output distributions. Uncertainty intervals are crafted from output distributions to inform the optimization algorithm. UP is often implemented with Monte Carlo (MC) sampling for large nonlinear systems, which can be difficult to implement within a constrained optimization …

Streamlined Production, Protection, And Purification Of Enzyme Biocatalysts Using Virus-Like Particles And A Cell-Free Protein Synthesis System, Seung O. Yang, Joseph P. Talley, Gregory H. Nielsen, Kristen M. Wilding, Bradley Charles Bundy

Faculty Publications

Enzymes play an essential role in many different industries; however, their operating conditions are limited due to the loss of enzyme activity in the presence of proteases and at temperatures significantly above physiological conditions. One way to improve the stability of these enzymes against high temperatures and proteases is to encapsulate them in protective shells or virus-like particles. This work presents a streamlined, three-step, cell-free protein synthesis (CFPS) procedure that enables rapid in vitro enzyme production, targeted encapsulation in protective virus-like particles (VLPs), and facile purification using a 6× His-tag fused to the VLP coat protein. This process is performed …

The Design And Cell-Free Protein Synthesis Of A Pembrolizumab Single-Chain Variable Fragment, Landon E. Ebbert, Tyler J. Free, Mehran Soltani, Bradley Charles Bundy

Faculty Publications

Background/Objectives: Cancer is a leading cause of death. However, recently developed immunotherapies have shown significant promise to improve cancer treatment outcomes and survival rates. Pembrolizumab, a cancer immunotherapy drug, enables a strong T-cell response specifically targeting cancer cells to improve patient outcomes in more than 16 types of cancer. The increasing demand for pembrolizumab, the highest selling drug in 2023, increases global dependence on drug production, which can be vulnerable to supply chain disruptions. Methods: Cell-free protein synthesis (CFPS) is a rapid in vitro protein production method that could provide the production of an immunotherapy drug in an emergency and …

Transfer Learning For Thickener Control, Samuel Arce Munoz, John Hedengren

Faculty Publications

Thickener control is a key area of focus in the minerals processing industry, particularly due to its crucial role in water recovery, which is essential for sustainable resource management. The highly nonlinear nature of thickener dynamics presents significant challenges in modeling and optimization, making it a strong candidate for advanced surrogate modeling techniques. However, traditional data-driven approaches often require extensive datasets, which are frequently unavailable, especially in new plants or unexplored operational domains. Developing data-driven models without enough data representative of the dynamics of the system could result in incorrect predictions and consequently, unstable response of the controller. This paper …

Acoustofluidics-Based Intracellular Nanoparticle Delivery, Zhishang Li, Zhenhua Tian, Jason N. Belling, Joseph Rich, Haodong Zhu, Zhehan Ma, Hunter Bachman, Liang Shen, Yaosi Liang, Xiolin Qi, Liv K. Heidenreich, Yao Gong, Shujie Yang, Wenfen Zhang, Peiran Zhang, Yingchun Fu, Yibin Ying, Steven J. Jonas, Yanbin Li, Paul S. Weiss, Tony J. Huang

Faculty Publications

Controlled intracellular delivery of biomolecular cargo is critical for developing targeted therapeutics and cell reprogramming. Conventional delivery approaches (e.g., endocytosis of nano-vectors, microinjection, and electroporation) usually require time-consuming uptake processes, labor-intensive operations, and/or costly specialized equipment. Here, we present an acoustofluidics-based intracellular delivery approach capable of effectively delivering various functional nanomaterials to multiple cell types (e.g., adherent and suspension cancer cells). By tuning the standing acoustic waves in a glass capillary, our approach can push cells in flow to the capillary wall and enhance membrane permeability by increasing membrane stress to deform cells via acoustic radiation forces. Moreover, by coating …

Development Of A Stable And Buffered Reference Electrode For Binary Molten Chlorides Salts, Carlos Mejia, Nicholas Christensen, Ricardo Rodriguez Ceron, Devin Rappleye

Faculty Publications

The development of stable and buffered reference electrodes (REs) is crucial for molten salt electrochemistry, particularly in pyrochemical processing, such as electrorefining. These REs must maintain a stable potential to ensure precise control over electrorefining processes by preventing unwanted shifts in the potential that could lead to impurity deposition. This study evaluated metal chlorides and metal oxides as potential candidates for REs, with their stability assessed via electrochemical methods over extended durations. While metal chloride-based REs exhibited stable potential behavior over time, their response followed the Nernst equation, leading to potential shifts with varying concentrations of oxidized species. Metal oxide-based …

Sound Innovations For Biofabrication And Tissue Engineering, Mengxi Wu, Zhiteng Ma, Zhenhua Tian, Joseph Rich, Xin He, Jianping Xia, Ye He, Kaichun Yang, Shujie Yang, Kam W. Leong, Luke P. Lee, Tony Jun Huang

Faculty Publications

Advanced biofabrication techniques can create tissue-like constructs that can be applied for reconstructive surgery or as in vitro three-dimensional (3D) models for disease modeling and drug screening. While various biofabrication techniques have recently been widely reviewed in the literature, acoustics-based technologies still need to be explored. The rapidly increasing number of publications in the past two decades exploring the application of acoustic technologies highlights the tremendous potential of these technologies. In this review, we contend that acoustics-based methods can address many limitations inherent in other biofabrication techniques due to their unique advantages: noncontact manipulation, biocompatibility, deep tissue penetrability, versatility, precision …

Ignis: A One-Dimensional Laminar Flame Code, Jansen P. Berryhill, Jacob K. Spinti, David O. Lignell

Faculty Publications

Laminar flame codes have an important role in combustion modeling. They can provide a fundamental understanding of flame dynamics and provide a basis for building subgrid scale models in turbulent flow simulations. This paper presents Ignis, an open-source laminar flame code with the capability to offload submodels, like soot formation and radiation, using external packages and libraries. Ignis is written in C++, is documented with Doxygen, and is available on GitHub. It contains three different flame formulations: diffusion flames, premixed flames, and laminar flamelets solved in the mixture fraction coordinate. An option to facilitate creation of a diffusion flame table …

Joint Subarray Acoustic Tweezers Enable Controllable Cell Translation, Rotation, And Deformation, Liang Shen, Zhenhua Tian, Kaichun Yang, Joseph Rich, Jianping Xia, Neil Upreti, Jinxin Zhang, Chuyi Chen, Nanjing Hao, Zhichao Pei, Tony Jun Huang

Faculty Publications

Contactless microscale tweezers are highly effective tools for manipulating, patterning, and assembling bioparticles. However, current tweezers are limited in their ability to comprehensively manipulate bioparticles, providing only partial control over the six fundamental motions (three translational and three rotational motions). This study presents a joint subarray acoustic tweezers platform that leverages acoustic radiation force and viscous torque to control the six fundamental motions of single bioparticles. This breakthrough is significant as our manipulation mechanism allows for controlling the three translational and three rotational motions of single cells, as well as enabling complex manipulation that combines controlled translational and rotational motions. …

Hydrogen Underground Storage For Grid Electricity Storage: An Optimization Study On Techno-Economic Analysis, Yunzhi Chen, Daniel Hill, Blake Billings, John Hedengren, Kody Powell

Faculty Publications

This study performs a techno-economic analysis of hydrogen underground storage systems for grid electricity storage, evaluating their economic viability at the plant scale using dynamic optimization. It explores the feasibility of various system configurations and revenue models in the context of volatile electricity prices and the necessity for multiple revenue streams. The hypothesis tested is that large-scale hydrogen storage, despite its low round-trip efficiency, can be economically viable with the right mix of revenue streams. This study uses scenario-based analysis to assess the impacts of different system configurations, including engaging in time-shifting arbitrage, ancillary service markets and blending hydrogen with …

Flexible Operation Of Nuclear Hybrid Energy Systems For Load Following And Water Desalination, An Ho, Blake W. Billings, John Hedengren, Kody M. Powell

Faculty Publications

Nuclear hybrid energy systems (NHES) have the potential to provide dependable and emission-free electricity to the grid while also increasing the flexibility and reliability of the electrical grid. Molten salt reactor (MSR) technology can provide consistent, carbon-free electricity while also increasing efficiency, security, and sustainability and reducing nuclear waste. This study investigates the integration of Molten Salt Reactors (MSR) and conventional Pressurized Water Reactors (PWR) with desalination technologies: Direct Contact Membrane Distillation (DCMD), Multi-Stage Flash Distillation (MSFD), and Reverse Osmosis (RO). Dynamic first-principles models were developed and tested using real grid data from the New York Independent System Operator. The …

Electrochemical Investigation Of Moisture Byproducts In Molten Calcium Chloride, Rankin Shum, Marah Gragun, Tyler Williams, Devin Rappleye

Faculty Publications

Residual water in molten CaCl₂ reacts to form different byproducts, such as HCl, which can impact the corrosivity of the salt and efficiency of electrochemical operations, such as electrolytic oxide reduction and electrorefining. The ability to detect and quantify these byproducts electrochemically can provide feedback on the efficacy of vacuum drying and other purification methods, as well as the impact of these byproducts on process operations. An electrochemical signal’s association with the production of H₂ is verified and characterized using cyclic voltammetry (CV) and residual gas analysis. CV estimated a 2-electron exchange process associated with H2 production. CV …

Model Predictive Control Of A Grid-Scale Thermal Energy Storage System In Relap5-3d, Jaron Wallace, John Hedengren, Kody Powell, Matthew Memmott

Faculty Publications

This research delves into the integration and control of a Thermal Energy Storage (TES) system with a Small Modular Reactor (SMR), specifically the NuScale VOYGR SMR module in RELAP5-3D. The research methodology centered on modeling the NuScale VOYGR SMR, a light water pressurized water reactor (LWR) with a power output capacity of 77 MWe per module. The reactor and plant details were sourced from NuScale's final safety analysis report and supplemented by information from the NuScale website. The SMR plays a crucial role in energy generation, and to manage and dispatch the produced energy effectively, a robust storage system …

Acousto-Dielectric Tweezers Enable Independent Manipulation Of Multiple Particles, Liang Shen, Zhenhua Tian, Kaichun Yang, Joseph Rich, Jinxin Zhang, Jianping Xia, Wesley Collyer, Brandon Lu, Nanjing Hao, Zhichao Pei, Chuyi Chen, Tony Jun Huang

Faculty Publications

Acoustic tweezers have gained substantial interest in biology, engineering, and materials science for their label-free, precise, contactless, and programmable manipulation of small objects. However, acoustic tweezers cannot independently manipulate multiple microparticles simultaneously. This study introduces acousto-dielectric tweezers capable of independently manipulating multiple microparticles and precise control over intercellular distances and cyclical cell pairing and separation for detailed cell-cell interaction analysis. Our acousto-dielectric tweezers leverage the competition between acoustic radiation forces, generated by standing surface acoustic waves (SAWs), and dielectrophoretic (DEP) forces, induced by gradient electric fields. Modulating these fields allows for the precise positioning of individual microparticles at points where …

Comparing Gas Composition From Fast Pyrolysis Of Live Foliage Measured In Bench-Scale And Fire-Scale Experiments, David R. Weise, Thomas H. Fletcher, Timothy J. Johnson, Wei Min Hao, Mark Dietenberger, Marko Princevac, Bret W. Butler, Sara S. Mcallister, Joseph J. O'Brien, E Louise Loudermilk, Roger D. Ottmar, Andrew T. Hudak, Akira Kato, Babak Shotorban, Shankar Mahalingham, Tanya L. Myers, Javier Palarea-Albaladejo, Stephen P. Baker

Faculty Publications

Background. Fire models have used pyrolysis data from oxidising and non-oxidising environments for flaming combustion. In wildland fires pyrolysis, flaming and smouldering combustion typically occur in an oxidising environment (the atmosphere). Aims. Using compositional data analysis methods, determine if the composition of pyrolysis gases measured in non-oxidising and ambient (oxidising) atmospheric conditions were similar. Methods. Permanent gases and tars were measured in a fuel-rich (non-oxidising) environment in a flat flame burner (FFB). Permanent and light hydrocarbon gases were measured for the same fuels heated by a fire flame in ambient atmospheric conditions (oxidising environment). Log-ratio balances of the measured gases …

Effect Of Local Chain Stiffness On Oligomer Crystallization From A Melt, Pierre Kawak, Christopher Akiki, Douglas R. Tree

Faculty Publications

While the process by which a polymer crystal nucleates from the melt has been extensively studied via molecular simulation, differences in polymer models and simulated crystallization conditions have led to seemingly contradictory results. We make steps to resolve this controversy by computing low-temperature phase diagrams of oligomer melts using Wang-Landau Monte Carlo simulations. Two qualitatively different crystallization mechanisms are possible depending on the local bending stiffness potential. Polymers with a discrete bending potential crystallize via a single-step mechanism, whereas polymers with a continuous bending potential can crystallize via a two-step mechanism that includes an intermediate nematic phase. Other model differences …

Ready, Set, Grow: From Micelles To Giant Vesicles Via Biocatalytic Activation, Nicholas P. Bair, Qinyu Zhu, Bryon A. Staynings, Douglas R. Tree, Walter F. Paxton

Faculty Publications

Controlling physicochemical processes that drive changes in supramolecular aggregates is an important objective toward creating artificial soft micro- and nanomachines. Previous research explored the morphology control of membrane-based materials subjected to externally imposed chemical stimuli. Here, we modulate the microscale morphology of pH-responsive assemblies by using biocatalysis to internally generate changes in global pH. Catalytic reactions offer flexibility in the mechanism and rate at which stimuli are introduced to responsive assemblies, ultimately enabling precision and control over size and morphology. We observed, by dynamic light scattering and fluorescence microscopy, substantial microscale differences between assemblies subjected to manually titrated pH changes …

Characteristics Of Pyrolysis Products Of California Chaparral And Their Potential Effect On Wildland Fires, Mahsa Alizadeh, David R. Weise, Thomas H. Fletcher

Faculty Publications

The aim of this study was to investigate the pyrolysis of selected California foliage and estimate the energy content of the released volatiles to show the significance of the pyrolysis of foliage and its role during wildland fires. While the majority of the volatiles released during the pyrolysis of foliage later combust and promote fire propagation, studies on the energy released from combustion of these compounds are scarce. Samples of chamise (Adenostoma fasciculatum), Eastwood’s manzanita (Arctostaphylos glandulosa), scrub oak (Quercus berberidifolia), hoaryleaf ceanothus (Ceanothus crassifolius), all native to southern California, and sparkleberry …

Electrochemical Identification Of Metal Chlorides In Eutectic Licl-Kcl Without Prior Knowledge Of Analyte Identities, Tyler Williams, Jason Torrie, Mark Schvaneveldt, Ranon Fuller, Greg Chipman, Devin Rappleye

Faculty Publications

The identities of unknown analytes within four eutectic LiCl-KCl melts were determined using electrochemical methods, simulating the uncertainty of electrochemically probing an electrorefiner salt bath or molten salt nuclear reactor. With a variety of electrochemical methods (e.g. cyclic voltammetry, chronopotentiometry, and square-wave voltammetry), and electroanalytical techniques (e.g. semi-differentiation), every analyte was positively identified, although one false positive occurred because of an unexpected chemical interaction. This study highlights some remaining challenges for the use of electrochemical sensors in nuclear material control and accountability in molten salts: (1) quantification of analytes without the use of calibration curves (e.g. error in property values, …

Chemical Herding As A Multiplicative Factor For Top-Down Manipulation Of Colloids, Mark N. Mcdonald, Douglas R. Tree, Cameron K. Peterson

Faculty Publications

Colloidal particles can create reconfigurable nanomaterials, with applications such as color-changing, self-repairing, and self-regulating materials and reconfigurable drug delivery systems. However, top-down methods for manipulating colloids are limited in the scale they can control. We consider here a new method for using chemical reactions to multiply the effects of existing top-down colloidal manipulation methods to arrange large numbers of colloids with single-particle precision, which we refer to as chemical herding. Using simulation-based methods, we show that if a set of chemically active colloids (herders) can be steered using external forces (i.e., electrophoretic, dielectrophoretic, magnetic, or optical forces), then a larger …

Communication—The Development Of A Stable And Practical Saturated Reference Electrode For Molten Chloride Salt Systems, J. Marvin Torrie, Ranon Fuller, Devin Rappleye

Faculty Publications

A simply constructed, stable, Ni/Ni²⁺ saturated reference electrode (SRE) has potential to measure thermodynamic behavior of molten chloride salts more reliably. Like the Ag/Ag⁺ reference electrode (RE), the Ni/Ni²⁺ SRE is made of commercially available materials. Initial experiments in molten CaCl2 and LiCl show the Ag/Ag⁺ RE potential drifting two times faster than the SRE. Furthermore, experiments show the replicability of SREs by comparing two Ni/Ni²⁺ SREs with different compositions of NiCl₂ which is supportive of saturated phase behavior.

Engineering The Signal Resolution Of A Paper-Based Cell-Free Glutamine Biosensor With Genetic Engineering, Metabolic Engineering, And Process Optimization, Tyler J. Free, Joseph P. Talley, Chad D. Hyer, Catherine J. Millar, Joel S. Griffitts, Bradley Charles Bundy

Faculty Publications

Specialized cancer treatments have the potential to exploit glutamine dependence to increase patient survival rates. Glutamine diagnostics capable of tracking a patient’s response to treatment would enable a personalized treatment dosage to optimize the tradeoff between treatment success and dangerous side effects. Current clinical glutamine testing requires sophisticated and expensive lab-based tests, which are not broadly available on a frequent, individualized basis. To address the need for a low-cost, portable glutamine diagnostic, this work engineers a cell-free glutamine biosensor to overcome assay background and signal-to-noise limitations evident in previously reported studies. The findings from this work culminate in the development …

Acoustofluidic Scanning Fluorescence Nanoscopy With A Large Field Of View, Geonsoo Jin, Neil Upreti, Joseph Rich, Jianping Xia, Chenglong Zhao, Tony Jun Huang

Faculty Publications

Large-field nanoscale fluorescence imaging is invaluable for many applications, such as imaging subcellular structures, visualizing protein interactions, and high-resolution tissue imaging. Unfortunately, conventional fluorescence microscopy requires a trade-off between resolution and field of view due to the nature of the optics used to form the image. To overcome this barrier, we developed an acoustofluidic scanning fluorescence nanoscope that simultaneously achieves superior resolution, a large field of view, and strong fluorescent signals. The acoustofluidic scanning fluorescence nanoscope utilizes the superresolution capabilities of microspheres that are controlled by a programmable acoustofluidic device for rapid fluorescence enhancement and imaging. The acoustofluidic scanning fluorescence …

Model Of The Effect Of Voltage On Contact Angle In An Electrolytic Cell Reaction, Aaron Essilfie

Reviews, Analyses, and Instructional Studies in Electrochemistry (RAISE)

This paper investigates the hypothesis that the contact angle at the meniscus of an electrode-electrolyte can be altered during a redox reaction through the coupled understanding of electrowetting and capillarity rise. Recent studies in electrowetting have focused on dielectric surfaces but research on contact angle at the electrode-electrolyte surface is lacking. The study employs a basic electrolytic cell. By applying principles of electrowetting and capillary rise the research aims to understand the relationship between applied voltage and contact angle, to advancements in electrochemistry and microfluidics.

Review Of Cyclic Voltammetry Measurements For Uranium In Flinak Molten Salt, Jackson Ivory

Reviews, Analyses, and Instructional Studies in Electrochemistry (RAISE)

The electrochemical behavior of uranium FLiNaK molten salts is explored, focusing on cyclic voltammetry (CV) as a powerful tool for redox characterization and diffusion studies. Through a comprehensive review of recent research, the study highlights the significance of CV in understanding electrode kinetics, material compatibility, and process optimization in molten salt environments. The findings underscore the potential of FLiNaK molten salt reactors in advancing nuclear energy technologies, fuel processing, and waste management strategies. Collaborative interdisciplinary efforts are emphasized to address challenges and accelerate innovation in electrochemical methods for nuclear applications.

Model To Demonstrate Effects Of Mass Transfer And Applied Current In An Electrolytic Cell, George Ankrah

Reviews, Analyses, and Instructional Studies in Electrochemistry (RAISE)

This study investigates the relationship between applied current and resulting cell potential in an electrolytic system, considering the transport of electroactive species. By applying Michael Faraday's laws of electrolysis and the Nernst-Planck equation, the behavior of electroactive species in diffusion-controlled systems with and without stirring is modeled. The plots demonstrate how stirring enhances ion transport and establishes a stable Nernst diffusion layer, affecting the kinetics of electrochemical reactions. Understanding these dynamics is crucial for optimizing electrolysis processes.