Chemical Engineering Commons^™

Gum Arabic-Capped Silver Nanoparticles For Electrochemical Amplification Sensing Of Methylene Blue In River Water, Ziad Khalifa, Moustafa Zahran, Magdy Zahran, Magdi Abdelazzem

Chemical Engineering

Herein, a novel electrochemical amplification sensor is developed for detecting methylene blue (MB) us- ing gum Arabic-capped silver nanoparticles (AgNPs) for the first time. Gum Arabic-AgNPs were fabricated via a direct chemical reduction technique using silver nitrate as an AgNPs precursor and gum Arabic as a reducing and capping agent. They were characterized using ultraviolet-visible (UV–Vis) spectrophotom- etry, square wave voltammetry (SWV), and transmission electron microscopy (TEM). UV–Vis and SWV results show the characteristic absorption and electrochemical oxidation peaks of the AgNPs at 431 nm and 0.18 V, respectively. Additionally, TEM images of the AgNPs show that they are spherical …

Degumming Of Hemp Fibers Using Combined Microwave Energy And Deep Eutectic Solvent, Bulbul Ahmed

LSU Master's Theses

Hemp is considered as one of the sustainable agricultural fiber materials. Degumming or surface modification of hemp bast is needed to produce single fibers for ensuing textile and industrial applications. The traditional degumming process necessitates a high amount of alkali, which causes detrimental environmental pollution. This study offers a new method to degum hemp fibers with reduced use of harmful alkali and precious water resources. In this work, hemp bast fibers were degummed by using combined microwave energy and deep eutectic solvent (DES). The properties of hemp fibers manufactured by this method were investigated and compared with the traditional alkali …

Epoxy Curing: Paramount Or Trivial? A Cure Path Dependent Inquiry, Jared Bates

Dissertations

The presented research delves into epoxy network formation corroborating reactant concentration profiles and physical property development throughout cure, providing an experimental basis for burgeoning molecular dynamics and coarse-grained simulation methodologies. Herein, three primary subjects were investigated: the first two examine neat and toughened epoxide/amine network formation with respect to various cure profiles aimed at altering reaction pathways, the final chapter intends to augment traditionally utilized activation energy (E_a) methodologies.

Neat and toughened epoxide/amine slurries were monitored in-situ throughout cure via near infrared (NIR) spectroscopy and rheological techniques. Functional group conversion and moduli development were related with specific attention …

Phase-Field Modeling Of The Polymer Membrane Formation Process For Micro- And Ultra-Filtration, Michael Rosario Cervellere

Graduate Theses and Dissertations

Porous polymer membrane filters are widely used in separation and filtration process. Micro- and ultra-filtration membranes are commonly used in biopharmaceutical applications such as filtering viruses and separating proteins from a carrier solution. The formation of these membrane filters via phase inversion is a complex and interconnected process where varying casting conditions can have a wide variety of effects on the final membrane morphol- ogy. Tailoring membrane filters for specific performance characteristics is a tedious and time consuming process. The time and length scales of membrane formation make it extremely difficult to experimentally observe membrane formation. Modeling the membrane formation …

Mechanisms Of Spontaneous Curvature Inversion In Compressed Graphene Ripples For Energy Harvesting Applications Via Molecular Dynamics Simulations, James M. Mangum, Ferdinand Harerimana, Millicent N. Gikunda, Paul M. Thibado

Physics Faculty Publications and Presentations

Electrically conductive, highly flexible graphene membranes hold great promise for harvesting energy from ambient vibrations. For this study, we built numerous three-dimensional graphene ripples, with each featuring a different amount of compression, and performed molecular dynamics simulations at elevated temperatures. These ripples have a convex cosine shape, then spontaneously invert their curvature to concave. The average time between inversion events increases with compression. We use this to determine how the energy barrier height depends on strain. A typical convex-to-concave curvature inversion process begins when the ripple’s maximum shifts sideways from the normal central position toward the fixed outer edge. The …

Investigation Of Membrane Based Processes For Biomedical Applications, Efecan Pakkaner

Graduate Theses and Dissertations

As substantial developments were achieved in nanotechnology and polymer engineering, especially in the last few decades, the use of membranes and membrane-based procedures was found to be expanding into more and more research and development areas; including biological engineering, life sciences and biomedical engineering. Not only have they been the main focus of meaningful research, but they have also been the main pieces of the solutions to very thorny problems encountered within a wide range of applications from microfluidics to water treatment, thanks to their versatility, cost-effectiveness and biocompatibility, when compared to conventional separation techniques. To celebrate and embrace these …

High Performance Mixed-Matrix Electrospun Membranes For Ammonium Removal From Wastewaters, Shu-Ting Chen, Sumith Ranil Wickramasinghe, Xianghong Qian

Chemical Engineering Faculty Publications and Presentations

Mixed-matrix electrospun membranes were developed to investigate ammonium removal from low ammonium concentration wastewaters for the first time. Particles derived from the inexpensive zeolite 13X were successfully incorporated into polyethersulfone (PES) matrices. The fabricated mixed-matrix electrospun membranes demonstrate high ammonium removal capacity reaching over 55 mg/g_zeolite, more than 2.5 times higher than the previously fabricated mixed-matrix membranes via non-solvent induced phase inversion. Moreover, the membranes fabricated exhibit high permeability and ease of regeneration. Over 90% of total ammonium nitrogen (TAN) can be removed from low TAN wastewaters such as aquaculture wastewaters. In addition to zeolite 13X, other zeolite …

Promotion Of Human Schwann Cell Proliferation Using Heparin/Collagen Coated Nerve Conduits, John Magness

Chemical Engineering Undergraduate Honors Theses

Often in the aftermath of an injury or surgery, the sense of touch and muscle control is lost in the affected area as nerves are damaged or severed and fail to grow back completely. The regeneration of the nerve cells can be promoted by treating the nerves with nerve conduits. Nerve conduits are hollow cylinders of bio-compatible materials that can be surgically implanted to the disconnected nerve to promote and direct the growth of nerves. The objectives of this research are to investigate the ability of nerve conduits treated with layer-by-layer coatings to promote the growth of Schwann cells, to …

Peptoid-Based Microsphere Coatings For Biomaterial Applications, Jesse Leland Roberts

Graduate Theses and Dissertations

Peptoids are peptidomimetic oligomers that predominantly harness similarities to peptides for biomimetic functionality. The incorporation of chiral, aromatic side chains in the peptoid sequence allows for the formation of distinct secondary structures and self-assembly into supramolecular assemblies, including microspheres. Peptoid microspheres can be coated onto substrates for potential use in biosensor technologies, tissue engineering platforms, and drug-delivery systems. They have the potential for use in biomedical applications due to their resistance to proteolytic degradation and low immunogenicity. This dissertation focuses on the physical characteristics and robustness of the peptoid microsphere coatings in various physiological conditions, along with their ability to …

Biopolymeric Materials For Tissue Regeneration, Cell Manufacturing, And Drug Delivery, David Alfonso Castilla-Casadiego

Graduate Theses and Dissertations

The development of materials for tissue regeneration, cell manufacturing, and drug delivery is possible by the manipulation of polymer properties and the use of three different techniques including layer-by-layer, electrospinning, and molding technique.

By applying the layer-by-layer technique over biomaterials, it is possible to develop polymeric multilayers that promote a more favorable environment for cellular functionality, increasing the possibility of improving their acceptance in the area of implantation. IRVASE demonstrated being a powerful technique that allows for a reliable characterization of the physical-chemical and thermal properties of the fabricated surfaces. This opens the possibility to monitor the design of surfaces …

Husky Hand: A Low-Cost Electro-Mechanical Prosthetic Arm For The Underprivileged, Adam Robert

Thinking Matters Symposium

A continuation of a low-cost prosthetic upper limb prototype design which was investigated in EGN 301. The prosthetic is specifically designed for the needs and requirements of under privileged individuals in the Dominican Republic with upper limb amputations. The project focuses on the creation of an open-source computer aided prosthetic hand/arm model. The design allows consumer-grade fused filament fabrication (FFF) 3-D printers to be used. The improved design allows for the integration of the PQ-12 linear actuator for grasp and finger control. This simplifies the assembly, while, also reducing the size and mass of the whole unit. Producing a low-cost …

Peptoid Microsphere Coatings To Improve Performance In Sandwich Elisa Microarrays, Jesse L. Roberts, German R. Perez Bakovic, Shannon L. Servoss

Chemical Engineering Faculty Publications and Presentations

Enzyme-linked immunosorbent assay (ELISA) microarray performance is limited by low assay sensitivity and dynamic range. Increasing the surface area for reagent binding can help to improve performance, but standard techniques such as roughening the surface or adding a polymer coating lead to increased non-specific fluorescence and do not have reproducibly improved performance. Another approach to increase surface area is adding a microsphere coating on the surface. Poly-N-substituted glycine (peptoid) microspheres are ideal for this application due to low immunogenicity, protease-resistance, and biocompatibility. Peptoids are polymers with a backbone similar to peptides, but with the side chains appended to nitrogen rather …

Melamine Derivatives As Highly Flame Retardant Additives For Bio-Based Rigid Polyurethane Foams, Niloofar Arastehnejad

Electronic Theses & Dissertations

MELAMINE DERIVATIVES AS HIGHLY FLAME RETARDANT ADDITIVES FOR BIO-BASED RIGID POLYURETHANE FOAMS

Rigid foams, which are mainly used in construction, refrigerators, automotive industries are one of the important types of polyurethanes with great potential in insulation and energy efficiency. Unfortunately, rigid polyurethane foams are highly flammable and catch fire in a short amount of time as well as spread the flame quickly. Hence, rigid foams are considered hazardous materials due to life-threatening situations and environmental issues.

To counter that, nitrogen-based compounds as non-halogenated flame retardants are an effective, low-cost, and eco-friendly option. It has been shown that melamine derivates as …

High Temperature Polymer Electrolytes For Hydrogen Fuel Cells And Electrochemical Pumps, Gokul Venugopalan

LSU Doctoral Dissertations

Hydrogen fuel cell and separation technologies such as proton exchange membrane fuel cells (PEMFCs) and electrochemical hydrogen pump (ECHP) offer a profound advantage in the transition to a low-carbon economy. An imperative hitch in hydrogen fuel cells and ECHP technology has been the electrocatalyst poisoning by carbon monoxide (CO) and other contaminants in the reactant mixture. By operating, hydrogen fuel cells and ECHPs at high temperatures (>200 °C), the effect of CO adsorption on the electrocatalyst surface could be curtailed. The high-temperature operation of devices necessitates a proton exchange membrane (PEM) to operate under anhydrous conditions.

In this work, …

Abiotic Sensor For Electrochemical Determination Of Chlorpyrifos In Natural Water Based On The Inhibition Of Silver Nanoparticles Oxidation, Ziad Khalifa, Moustafa Zahran, Magdy Zahran, Magdi Abdelazzem

Chemical Engineering

Chlorpyrifos, organophosphorus pesticide, is a persistent organic pollutant that may cause serious health problems. Herein, a simple, green, and sensitive electrochemical inhibition sensor based on silver nanoparticles (AgNP)-modified glassy carbon (GC) electrode was developed for the determination of chlorpyrifos in natural water for the first time. The chemical reduction technique based on natural reducing and capping agents such as dissolved organic matter (DOM), natural latex (NL) and mucilage was employed for AgNP synthesis. DOM-AgNP, NL-AgNP, and Mucilage-AgNP were immobilized on GC by sticking technique under the same voltammetric and electrolytic conditions. The oxidation behavior of the three modified electrodes was …

Cellulose-Based Polymer Electrolyte Derived From Waste Coconut Husk: Residual Lignin As A Natural Plasticiser, Chua Kai Ying

Student Works (2020-2029)

Polymer electrolyte (PE) finds many applications in the fabrication of electrochemical devices such as batteries, solar cells, supercapacitors, and electrochromic windows. The usage of cellulose from the waste of coconut husk is one alternative in using natural polymer as a green electrolyte. However, due to its high crystallinity, the usage of plasticiser is advantageous to reduce the crystallinity of cellulose. Lignin which co-exists with cellulose in the cell walls of the plants could act as a natural plasticiser in preparing a good polymer electrolyte. In this work, cellulose was isolated from waste coconut husk (Cocos nucifera), modified into water-soluble carboxymethylcellulose …

Performance Of Waterborne Intumescent Coating With Hybrid Industrial And Biofillers For Steel Protection, Khairunisa Md Nasir

Student Works (2020-2029)

In recent decades, the disastrous accidents caused by damaged steel structure in the event of the fire have reminded people of the risk of fire in industrial buildings. The use of intumescent coatings is one of the most efficient methods to protect materials against fire. The coating comprises three active elements bounded together with a binder, which then reacts together at higher temperatures. Under the action of heat, the coating expands and forms a thick porous char layer to insulate the substance, thereby prolonging the building from collapsing under severe fire conditions. Considering ecological issues, the use of waterborne resin …

Valorization Of Xylan In Agroforestry Waste Streams, Harrison Appiah

Graduate Theses, Dissertations, and Problem Reports (ETD)

Valorization of Xylan in Agroforestry Waste Streams.

Harrison Appiah

Microwave-assisted deep eutectic solvent and gamma-valerolactone metallic chloride catalyzed conversion of xylan to furfural were investigated using a 2x3 factorial experimental design at two levels of percent microwave power, reaction time, and catalyst concentration. The levels of each factor studied were (20%, 60% microwave power, 2, 4 minutes, and 10, 20mg) respectively. The effect of three metallic chloride catalysts (LiCl, FeCl3.6H20, CuCl2) on the conversion of xylan to furfural was also investigated. The gamma-valerolactone-ferric chloride sent system exhibited the highest mean yield of furfural (56.50%). The next highest furfural yield of …

Complementary Techniques To Study The Behavior Of Water And The Effect On Diffusion And Degradation In Hydrogels, Paige Rockwell

Master’s Theses

Hydrogels exhibit biocompatibility in a range of biomedical applications, including drug delivery. This thesis aims to develop complementary techniques to measure the diffusion and degradation behaviors within an injectable, hydrolytically degradable hydrogel, formed via the covalent crosslinking of ethoxylated trimethylolpropane tri-3- mercaptopropionate (ETTMP) and poly(ethylene glycol) diacrylate (PEGDA), to determine its suitability as a drug delivery matrix. The characterization of water as either free, within the network openings of the hydrogel, or bound, tightly associated with the polymer chains, was determined using differential scanning calorimetry (DSC). The mobility of each type of water within the hydrogels was determined via nuclear …

Extraction Of Micro- And Nano-Plastic Particles From Water Using Hydrophobic Natural Deep Eutectic Solvents, Jameson R. Hunter

Theses and Dissertations--Biosystems and Agricultural Engineering

The production of plastic and the amount of waste plastic that enters the environment increases every year. Synthetic polymers will gradually break down into particles on the micro- and nano-scale. The micro- and nano-plastics pose a significant ecological harm by transporting toxic chemicals and causing inflammation and cellular damage when ingested. Two common plastics are polyethylene terephthalate (PET) and Polystyrene (PS), and a newer bioplastic polylactic acid (PLA) that has become a popular alternative. Deep eutectic solvents are a recently discovered solvent composed of a hydrogen bond donor and hydrogen bond acceptor and have been proposed as a cheaper alternative …

Establishing Independent Tunability Of The Mechanical And Transport Properties Of Polymer Gels, Lucas Rankin

Master’s Theses

Polymer gels can be used in the fabrication of materials for filtering liquid and gaseous media, solid-state electrolytes, and transdermal medical patches. This diverse range of applications primarily relies on the transport and mechanical properties of polymer gels. Both sets of properties have shown excellent tunability, but typically in a coupled fashion. Establishing the independent tunability of the transport and mechanical properties of polymer gels (using simple, cost-effective methods) is paramount if polymer gels are to be used to their full potential. Specifically, block copolymer gels self-assemble into organized nanoscale networks within the gel solvent, which allows for facile control …

Helicopter Shaft Heating Parameters For Polyamide-11 Coating, Selim Kevran Ph.D, Uğur Ati̇ci̇

International Journal of Aviation, Aeronautics, and Aerospace

In this study, the heating parameters required for polyamide-11 (P11) coating of the helicopter shaft were investigated. The torsion value created by the force applied to the middle of the helicopter's shaft is measured. Heating before coating affects the torsion value of the shaft. A new heating mechanism has been designed to cover the shaft surface without changing the torsion value of the shaft. Thus, the coating surface is left inside the furnace and the torsion measurement area outside of the furnace. Taguchi method was used to determine heating parameters such as furnace type, initial temperature and heating time. The …

The Critical Role Of Dynamic Surface Tension Of Surfactants On The Impact Dynamics Of Water Droplets, Amir Esmaeili, Reza Mohammadi

Graduate Research Posters

Due to their time-dependent surface tension, the addition of surface-active agents or surfactants to water for specific applications has made controlling the impact dynamics of these droplets a complex phenomenon. This work investigates the influence of the molecular weight, concentration, and ionic nature of the surfactants as well as the substrate surface characteristics on the impact dynamics of surfactant-laden droplets using a high-speed camera at 10000 frames per second. Sodium dodecyl sulfate, hexadecyltrimethylammonium bromide, and n-decanoyl-n-methylglucamine were used as anionic, cationic, and nonionic surfactants, respectively. We used hydrophilic glass slides, hydrophobic polytetrafluoroethylene, and superhydrophobic alkyl ketene dimer (AKD) as substrates. …

Assessing Solvent Viscosity Impact On The Physical Characteristics Of Polymeric Organogels, Cameron Hong

Honors Theses

Traditionally, studies of polymeric organogels focus on the impact of polymer factors (e.g., molecular weight and polymer concentration) on the gels’ mechanical and transport properties. Alternatively, this study seeks to assess the impact of altering solvent viscosity, while holding polymer factors constant. The gels in this study were composed of different viscosity mineral oils, styrene-ethylene-butylene-styrene (SEBS) triblock copolymer as a gelator, and oleic acid (OA) as a model drug. Samples were formulated to have 6.5, 11.2, and 15.7 wt% SEBS copolymer for each mineral oil, varying in viscosity from ≈30 mPa*s to ≈500 mPa*s. Uniaxial mechanical testing was performed to …

Assessing The Impact Of Block-Selective Homopolymers On The Diffusion Of Payload Through Polymeric Organogels, Ian Coates

Honors Theses

Styrenic polymer gels have received recent attention for their application in transdermal patches due to their unique properties. Previous research in the pharmaceutical industry has identified that polymeric gels, specifically styrenic gels, have the potential to encompass multiple functions of the transdermal delivery patch including controlling mechanical and delivery properties. To tailor styrenic gels either the gel nanostructure or the drug complex can be controlled. Specifically, this thesis investigated the effect of gel nanostructure in an attempt to control the gel diffusivity and mechanical properties. To control gel nanostructure a phase selective styrene homopolymer was used at varying concentrations. It …

Determination Of Hydrogel Degradation By Passive Mechanical Testing, Avery Rosh-Gorsky

Honors Theses

This paper details a new technique to measure the mechanical properties of ETTMP PEGDA hydrogels using Hertz Contact Theory and simultaneously analyze both the model drug release and gel erosion in situ. This method involves curing a drug loaded hydrogel in a standard cuvette and placing a glass bead and phosphate buffer solution (PBS). Over time, the cross-linked network of the hydrogel breaks down, and, as a result, the ball sinks into the hydrogel. This method provides a macroscopic and inexpensive way to continuously and passively measure properties of the hydrogel as the hydrogel degrades. By plotting both the …

Doping Graphene With Substitutional Mn, Pin-Cheng Lin, Renan Villarreal, Simona Achilli, Harsh Bana, Maya N. Nair, Antonio Tejeda, Ken Verguts, Stefan De Gendt, Manuel Auge, Hans Hofsäss, Steven De Feyter, Giovanni Di Santo, Luca Petaccia, Steven Brems, Guido Fratesi, Lino M. C. Pereira

Advanced Science Research Center

We report the incorporation of substitutional Mn atoms in high-quality, epitaxial graphene on Cu(111), using ultralow-energy ion implantation. We characterize in detail the atomic structure of substitutional Mn in a single carbon vacancy and quantify its concentration. In particular, we are able to determine the position of substitutional Mn atoms with respect to the Moiré superstructure (i.e., local graphene-Cu stacking symmetry) and to the carbon sublattice; in the out-of-plane direction, substitutional Mn atoms are found to be slightly displaced toward the Cu surface, that is, effectively underneath the graphene layer. Regarding electronic properties, we show that graphene doped with substitutional …

Wetting Transition On 3d-Printed Featured Surface, Hannah Pineault

Williams Honors College, Honors Research Projects

The primary objective of this research project was to gain a better understanding of surface characteristics to produce a long-lasting superhydrophobic or superhydrophilic surface. In other words, when will a droplet of water remain on top of a featured surface and when does the transition occur to water filling the grooves of the surface? This research focused on how to best fabricate porous structures that would stay completely dry at all times by preventing the liquid from penetrating. In particular, we followed the behaviors of water droplets placed on top of 3-D printed featured surfaces with various geometries and surface …

Comparison Of The Effects Of Hofmeister Ions On Transition Temperature Of Two Thermoresponsive Polymers, Ashley Knight

Williams Honors College, Honors Research Projects

It has been hypothesized that poly(vinylmethylether) (PVME) could be used to replace poly(N-isopropylacrylamide) (pNIPAAM) in various thermoresponsive applications based on literature searches and previous lab experiments. PVME is cheaper and easier to process, and would make pNIPAAM applications more cost effective. In order to verify this, experimental data was gathered on the effects of four anions from the Hofmeister series (SO₄₂-, Cl-, I-, and SCN-) on the lower critical solution temperature (LCST) of pNIPAAM and compared to previous data collected on PVME. Commercial pNIPAAM from Sigma Aldrich and Polysciences were used. The reported LCST range for pNIPAAM is …

Investigation Of Surface Charge Using Faraday Bucket Measurements: Analysis On Electrospun Polyvinylidene Fluoride Fiber Mats, Ryan Kantenwein

Williams Honors College, Honors Research Projects

Piezoelectric polymer materials such as polyvinylidene fluoride exhibit beneficial properties for use in personal protective equipment (PPE) against viral contaminants and other foreign microparticles. The electrospinning process of this material allows for surface charge to develop over a controlled surface area. Kynar 761 at 10 wt% demonstrates increased surface charge after withstanding a flow of aerated NaCl particles from a TSI 8130 instrument. Utilizing voltage measurements from a Faraday bucket, 18 wt% Kynar 761 and MG-15 exhibit surface charge when undergoing an electrospinning process; however, Kynar MG-15 displays lower charge values than that of Kynar 761. Several critical factors such …