Chemical Engineering Commons^™

Thermodynamics Of Concentrated Solid Solution Alloys, Michael C. Gao, Chuan Zhang, Pan Gao, Fan Zhang, Lizhi Ouyang, Michael Widom, Jeffrey A. Hawk

Mathematical Sciences Faculty Research

This paper reviews the three main approaches for predicting the formation of concentrated solid solution alloys (CSSA) and for modeling their thermodynamic properties, in particular, utilizing the methodologies of empirical thermo-physical parameters, CALPHAD method, and first-principles calculations combined with hybrid Monte Carlo/Molecular Dynamics (MC/MD) simulations. In order to speed up CSSA development, a variety of empirical parameters based on Hume-Rothery rules have been developed. Herein, these parameters have been systematically and critically evaluated for their efficiency in predicting solid solution formation. The phase stability of representative CSSA systems is then illustrated from the perspectives of phase diagrams and nucleation driving …

Computational Modeling Of High-Entropy Alloys: Structures, Thermodynamics And Elasticity, Michael C. Gao, Pan Gao, Jeffrey A. Hawk, Lizhi Ouyang, David E. Alman, Mike Widom

Mathematical Sciences Faculty Research

This article provides a short review on computational modeling on the formation, thermodynamics, and elasticity of single-phase high-entropy alloys (HEAs). Hundreds of predicted single-phase HEAs were re-examined using various empirical thermo-physical parameters. Potential BCC HEAs (CrMoNbTaTiVW, CrMoNbReTaTiVW, and CrFeMoNbReRuTaVW) were suggested based on CALPHAD modeling. The calculated vibrational entropies of mixing are positive for FCC CoCrFeNi, negative for BCC MoNbTaW, and near-zero for HCP CoOsReRu. The total entropies of mixing were observed to trend in descending order: CoCrFeNi > CoOsReRu > MoNbTaW. Calculated lattice parameters agree extremely well with averaged values estimated from the rule of mixtures (ROM) if the same crystal …

Formulation And Dissolution Of Polymer Strip Films For The Delivery Of Poorly Water-Soluble Drug Nanoparticles, Scott Matthew Krull

Dissertations

Polymer films have emerged as a promising platform for delivery of pharmaceutical products in recent years due to simplified processing, greater flexibility, and improved patient compliance over traditional solid dosage forms. However, the large majority of efforts have focused on incorporation of water-soluble drugs. The objective of this dissertation is to explore the robustness and versatility of the strip film platform for delivery of poorly water-soluble drug nanoparticles to ultimately develop a predictive model for drug release from such films.

The robustness of the polymer strip film platform to successfully deliver a variety of poorly water-soluble drug nanoparticles without the …

Co2 Reduction Over Noble Metal/Carbon Nanotube Catalyst, Yuan Zhu

Dissertations

Carbon nanotube-based Pt/Pd and Ru catalysts, independently synthesized by a microwave reaction technique, show good catalytic activity for CO2 reduction in the contexts of dry reforming (DR) of methane (CH₄ + CO₂ -> 2CO + 2H₂) and reverse water gas shift (RWGS) (H2 + CO₂ -> CO + H₂O). Reaction temperatures range from 773 to 973 K, with system pressure at 30 psig. The feed molar ratios CH4/CO₂ and CO₂/H₂ are varied from 0.5 to 2.0. Reactant conversions in DR and RWGS are strongly influenced by temperature and feed …

Assessment Of Nanocomposites Vs. Amorphous Solid Dispersions For Dissolution Enhancement Of Bcs Class Ii Drugs, Meng Li

Dissertations

Nanoparticle-based formulations (nanocomposites) and amorphous solid dispersions, shortly ASDs, are two major pharmaceutical formulation platforms used for the bioavailability enhancement of poorly water-soluble drugs. While they both have several advantages-disadvantages, a scientific comparative assessment of their drug release performance and dissolution mechanisms at different drug doses is not available. With the goal of addressing this issue, the dissertation aims to achieve three major objectives: (1) develop a processing-formulation understanding of wet media milling process for fast-efficient production of drug nanoparticles in stable nanosuspension form, (2) elucidate the impact of various classes dispersants on drug release rate and mechanisms during the …

Characterization Of Microporous Ectfe Membranes Exposed To Different Liquid Media And ?-Radiation And Nanoparticle Microfiltration Through Such Membranes, Na Yao

Dissertations

Microporous polymeric membranes are used in a variety of applications for separations, purification as well as barrier function. A major application is for microfiltration (MF). Changes in the properties of MF membranes exposed to acids, bases and organic solvents are of interest in semiconductor processing as well as in membrane contactor applications. Microfiltration membranes used for sterilization in beverage, biotechnology and pharmaceutical industries are sterilized by gamma radiation among others. Irradiation-induced degradation in membrane properties should be known. A variety of fluoropolymer-based microporous membranes are available with varying properties. Ethylene chlorotrifluoroethylene (ECTFE) membranes are a new addition and are of …

A Hierarchical Approach For Creating Electrically Conductive Network Structure In Polyurethane Nanocomposites Using A Hybrid Of Graphene Nanoplatelets, Carbon Black And Multi-Walled Carbon Nanotubes, Pashupati Pokharel, Dequan Xiao, Folarin Erogbogbo, Ozgur Keles, Dai Soo Lee

Chemistry and Chemical Engineering Faculty Publications

Hierarchical organization of carbon nanomaterials is the best strategy to combine desirable factors and synergistically impart mechanical and electrical properties to polymers. Here, we investigate the relaxation behavior of carbon nanofillers filled polyurethane (PU) with special reference to particle size and aspect ratio, filler morphology, filler loading to understand the conductive network formation of fillers in the PU matrix. Typically, an addition of 2 wt% hybrid fillers of graphene nanoplatelets (GNPs), conductive carbon black (CB) and multiwalled carbon nanotubes (MWCNTs) in PU at 1:1:2 mass ratio (GCM112-PU2) showed lowest surface resistivity ~10^6.8 ohm/sq along with highest improved mechanical properties. …

Vibration Modification To A.P.I. Fracture Short Term Conductivity Testing Procedure, Blake A. Ereaux

Graduate Theses & Non-Theses

The current API Short Term Fracture Conductivity (volume number) testing procedure provided by the American Petroleum Institute doesn't consistently provide repeatable results. For example, in an independent review of three commercial lab results testing the same sample of proppant the variation between the three had a data spread of nearly 80% (Anderson, 2013). Continuing and refocusing the research performed by Kent Blair's thesis "Modifying Fracture Conductivity Testing Procedures" (Montana Tech, 2015), the goal of this thesis is to expand the lab research results on the use of vibration in the cell loading procedure to improve the repeatability of test results. …

The Effect Of Mineral Composition On Shale Oil Recovery, Andrew Fakhry

Graduate Theses & Non-Theses

Identifying contact angles in porous media is essential for characterizing multiphase flow of fluids in reservoirs. Traditional methods to measure contact angles assume a homogenous structure of reservoir rock; however, microscale pictures by Scanning Electron Microscopes (SEM) show that rock composition varies even inside a single pore. In addition, the preferentiality of oil layer formation is different according to the minerals constituting the reservoir rock. As a result, contact angles have heterogeneous behavior at the pore-scale.

For the purpose of this research, contact angles are measured on the pure minerals that make up the main components of a Bakken reservoir …

Evaluation Of Methods To Model Hydraulic Fractures In Flow Simulation, Ben Doleshal

Graduate Theses & Non-Theses

Modern reservoir studies use reservoir simulation to predict future production and plan reservoir development. Due to the increase in production in unconventional reservoirs in recent years, the number of hydraulically fractured wells has risen drastically. The days of using simple analytic techniques to account for the production of a single hydraulic fracture in a vertical well are gone, and the need to be able to model numerous hydraulic fractures in many stages over long horizontals is required.

This brings up the study question of this research: What is the best way to model hydraulic fractures in a flow simulator? There …

Tuning Properties Of Poly(Ethylene Glycol)-Block-Poly(Simvastatin) Copolymers Synthesized Via Triazabicyclodecene, Theodora A. Asafo-Adjei, Thomas D. Dziubla, David A. Puleo

Biomedical Engineering Faculty Publications

Simvastatin was polymerized into copolymers to better control drug loading and release for therapeutic delivery. When using the conventional stannous octoate catalyst in ring-opening polymerization (ROP), reaction temperatures ≥ 200 °C were required, which promoted uncontrollable and undesirable side reactions. Triazabicyclodecene (TBD), a highly reactive guanidine base organocatalyst, was used as an alternative to polymerize simvastatin. Polymerization was achieved at 150 °C using 5 kDa methyl-terminated poly(ethylene glycol) (mPEG) as the initiator. ROP reactions with 2 kDa or 550 Da mPEG initiators were also successful using TBD at 150 °C instead of stannous octoate, which required a higher reaction temperature. …

Effect Of Bioglass Incorporation Into Electrochemically Aligned Collagen Threads On Mechanical Properties And Cell-Mediated Mineralization, Madhura Nijsure

Theses and Dissertations

Bone related diseases and disorders are a significant socioeconomic burden in the United States. Autografts and allografts are most commonly used for the treatment of bone defects and non-unions; however, they are associated with limitations such as donor site morbidity and immune rejection, respectively. Over the past few decades, bone tissue engineering (BTE) using scaffold and cells has garnered significant interest as an alternative method for the repair and regeneration of bone defects. Recreation of the tissue microenvironment via the development of biomimetic scaffolds that resemble the physicochemical aspects (i.e., composition, topography, stiffness) of native bone is a promising approach …

Role Of Surface Factors On Heterogeneous Ice Nucleation, Brittany Glatz

All Dissertations

Heterogeneous ice nucleation is the primary pathway for ice formation. However, the detailed molecular mechanisms by which surfaces promote or hinder ice nucleation are not well understood. We present results from extensive molecular dynamics and forward flux sampling (FFS) simulations of ice nucleation near modified surfaces. The surfaces are modified to investigate the effects of different surface factors on the rate and mechanism of ice nucleation. We find that the surface charge distribution has significant effects on ice nucleation. We also investigate the interplay of surface lattice and hydrogen bonding properties in affecting ice nucleation. We find that lattice matching …

Titanium Addition Influences Antibacterial Activity Of Bioactive Glass Coatings On Metallic Implants, Omar Rodriguez, Wendy Stone, Emil H. Schemitsch, Paul Zalzal, Stephen Waldman, Marcello Papini, Mark R. Towler

Chemical and Biochemical Engineering Faculty Research & Creative Works

In an attempt to combat the possibility of bacterial infection and insufficient bone growth around metallic, surgical implants, bioactive glasses may be employed as coatings. In this work, silica-based and borate-based glass series were synthesized for this purpose and subsequently characterized in terms of antibacterial behavior, solubility and cytotoxicity. Borate-based glasses were found to exhibit significantly superior antibacterial properties and increased solubility compared to their silica-based counterparts, with BRT0 and BRT3 (borate-based glasses with 0 and 15 mol% of titanium dioxide incorporated, respectively) outperforming the remainder of the glasses, both borate and silicate based, in these respects. Atomic Absorption Spectroscopy …

Potency And Cytotoxicity Of A Novel Gallium-Containing Mesoporous Bioactive Glass/Chitosan Composite Scaffold As Hemostatic Agents, Sara Pourshahrestani, Ehsan Zeimaran, Nahrizul Adib Kadri, Nicola Gargiulo, Hassan Mahmood Jindal, Sangeetha Vasudevaraj Naveen, Shamala Devi Sekaran, Tunku Kamarul, Mark R. Towler

Chemical and Biochemical Engineering Faculty Research & Creative Works

Chitosan-based hemostats are promising candidates for immediate hemorrhage control. However, they have some disadvantages and require further improvement to achieve the desired hemostatic efficiency. Here, a series of 1% Ga2O3-containing mesoporous bioactive glass-chitosan composite scaffolds (Ga-MBG/CHT) were constructed by the lyophilization process and the effect of various concentrations of Ga-MBG (10, 30, and 50 wt %) on the hemostatic function of the CHT scaffold was assessed as compared to that of Celox Rapid gauze (CXR), a current commercially available chitosan-coated hemostatic gauze. The prepared scaffolds exhibited >79% porosity and showed increased water uptake compared to that in CXR. The results …

Electrochemical Reduction Of Co2 Using Metal Nanoparticles, Evan Michael Andrews

LSU Doctoral Dissertations

The electrochemical reduction of CO₂ has been proposed as a method of storing electrical energy from renewable sources in the form of hydrocarbon fuels. By reverting CO₂ into high energy density fuels, a CO₂-neutral fuel cycle becomes possible while still hydrocarbon fueled engines. Cu and Au metals have been found to be particularly effective at catalyzing this reaction, yielding a majority of hydrocarbons and CO respectively. However, the CO₂ electroreduction reaction is still poorly understood and catalysts that possess both high energy efficiency and high yield are not yet developed. Nanoscale catalysts offer the ability …

Molecular Structure And Confining Environment Of Sn Sites In Single-Site Chabazite Zeolites, James W. Harris, Wei-Chih Liao, John R. Di Iorio, Alisa M. Henry, Ta-Chung Ong, Aleix Comas-Vives, Christopher Coperet, Rajamani Gounder

School of Chemical Engineering Faculty Publications

Chabazite (CHA) molecular sieves, which are industrial catalysts for the selective reduction of nitrogen oxides and the conversion of methanol into olefins, are also ideal materials in catalysis research because their crystalline frameworks contain one unique tetrahedral-site. The presence of a single lattice site allows for more accurate descriptions of experimental data using theoretical models, and consequently for more precise structure-function relationships of active sites incorporated into framework positions. A direct hydrothermal synthesis route to prepare pure-silica chabazite molecular sieves substituted with framework Sn atoms (Sn-CHA) is developed, which is required to predominantly incorporate Sn within the crystalline lattice. Quantitative …

A Carbon Nanotube Optical Reporter Maps Endolysosomal Lipid Flux, Jena V. Prakrit, Daniel E. Roxbury, Thomas V. Galassi, Leila Akkari, Christopher P. Horoszko, David B. Iaea, Januka Budhathoki-Uprety, Nina Pipalia, Abigail S. Haka, Jackson D. Harvey, Jeetain Mittal, Frederick R. Maxfield, Johanna A. Joyce, Daniel A. Heller

Chemical, Biomolecular, and Materials Engineering Faculty Publications

Lipid accumulation within the lumen of endolysosomal vesicles is observed in various pathologies including atherosclerosis, liver disease, neurological disorders, lysosomal storage disorders, and cancer. Current methods cannot measure lipid flux specifically within the lysosomal lumen of live cells. We developed an optical reporter, composed of a photoluminescent carbon nanotube of a single chirality, that responds to lipid accumulation via modulation of the nanotube’s optical band gap. The engineered nanomaterial, composed of short, single-stranded DNA and a single nanotube chirality, localizes exclusively to the lumen of endolysosomal organelles without adversely affecting cell viability or proliferation or organelle morphology, integrity, or function. …

Development Of Starch-Polyvinyl Alcohol (Pva) Biodegradable Film: Effect Of Cross-Linking Agent And Antimicrobials On Film Characteristics, Aniket Satish More, Chandani Sen, Madhusweta Das

Journal of Applied Packaging Research

To satisfy the need of developing eco-friendly flexible antimicrobial packaging film with minimum use of synthetic chemical ingredients, the present study examined the efficacy of citric acid (CA) as cross-linking agent and essential oils (EOs), viz., cinnamon essential oil (CEO) and oregano essential oil (OEO) as natural antimicrobials in corn starch-polyvinyl alcohol (CS-PVA) film. Compared to film prepared from filmogenic solution (FS) containing 75 kg CS+8.75 kg PVA+24.6 kg glycerol per m³ FS, film additionally containing CA at 0.07 kg/kg CS indicated 95% higher ultimate tensile strength (UTS) and 27% lower water vapor permeability (WVP). Film developed with incorporation …

The Effect Of Engineered Nanotopography Of Electrospun Microfibers On Fiber Rigidity And Macrophage Cytokine Production, Nicholas J. Schaub, Anthony R. D'Amato, Andrew Mason, David T. Corr, Erin Y. Harmon, Michelle R. Lennartz, Ryan J. Gilbert

Chemical and Biochemical Engineering Faculty Research & Creative Works

Currently, it is unknown how the mechanical properties of electro spun fibers, and the presentation of surface nano topography influence macrophage gene expression and protein production. By further elucidating how specific fiber properties (mechanical properties or surface properties) alter macrophage behavior, it may be possible to create electro spun fiber scaffolds capable of initiating unique cellular and tissue responses. In this study, we determined the elastic modulus and rigidity of fibers with varying topographies created by finely controlling humidity and including a non-solvent during electrospinning. In total, five fiber scaffold types were produced. Analysis of fiber physical properties demonstrated no …