Chemical Engineering Commons^™

Dynamics Of Nanoparticles In Fluids And At Interfaces, Weikang Chen

Dissertations, Theses, and Capstone Projects

In this thesis, we use molecular dynamics simulation to study three basic behaviors or properties of nanoparticles: deposition during droplets evaporation, slip boundary condition and Brownian motion. These three problems address the need for an in-depth understanding of the dynamics of nanoparticles in fluids and at interfaces. In the first problem, evaporation of the droplets dispersed with particles, we investigated the distribution of evaporative flux, inner flow field, density and temperature. And we use these numerical experiments to check on our hydrodynamic theory of the "coffee ring" phenomenon. The simulations reveal the connection between the particle interactions and the deposit …

Study Of Polyaniline For Use In An Organic Field Effect Transistor, Thomas Martin Sprinkle

Chemistry & Biochemistry Theses & Dissertations

Polyaniline's emeraldine base form was synthesized via chemical polymerization in HCl acidic media utilizing ammonium persulfate as the oxidant. Synthesis was done at room temperature and -30 'C and characterized for differences by X-ray diffraction, thermogravimetric analysis, and differential scanning calorimetry. Methanol soxhlet extraction was done to increase number average molecular weight from 77,400 to 81,000 and decrease the poly dispersity index from 3.82 to 2.14. Films were cast using N, N'- Dimethylpropyleneurea and N-Methylpyrrolidone and showed poor mechanical properties upon acidic doping.

Cyclic voltammetry was done with HC1 as the acidic media and an ITO coated slide as the …

Investigating The Stability Of Eliposomes At Elevated Temperatures, Ghaleb A. Husseini, William G. Pitt, Marjan Javadi

Faculty Publications

eLiposomes encapsulate a perfluorocarbon nanoemulsion droplet inside a liposome. Ultrasound is then used as a trigger mechanism to vaporize the perfluorocarbon, break the liposome, and release the desired drug to the tumor tissue. The purpose of this research is to show that eLiposomes synthesized using perfluoropentane are stable above the normal boiling point of the perfluoropentane and at body temperature and thus has potential for use in vivo. Experiments involving the release of fluorescent calcein molecules were performed on eLiposomes to measure the release of calcein at various temperatures in the absence of ultrasound. Results showed that eLiposomes are stable …

Investigating The Stability Of Eliposomes At Elevated Temperatures, Ghaleb A. Husseini, William G. Pitt, Marjan Javadi

Faculty Publications

eLiposomes encapsulate a perfluorocarbon nanoemulsion droplet inside a liposome. Ultrasound is then used as a trigger mechanism to vaporize the perfluorocarbon, break the liposome, and release the desired drug to the tumor tissue. The purpose of this research is to show that eLiposomes synthesized using perfluoropentane are stable above the normal boiling point of the perfluoropentane and at body temperature and thus has potential for use in vivo. Experiments involving the release of fluorescent calcein molecules were performed on eLiposomes to measure the release of calcein at various temperatures in the absence of ultrasound. Results showed that eLiposomes are stable …

Liquid Metal Electrodes For Rechargeable Batteries, Rutooj Deshpande, Juchuan Li, Yang-Tse Cheng

Chemical and Materials Engineering Faculty Patents

An electrode for a lithium ion battery includes a liquid metal having a melting point that is below the operating temperature of the battery, which transforms from a liquid to a solid during lithiation, and wherein the liquid metal transforms from a solid to a liquid during delithiation.

Use Of Blood Oxygenator Membrane Units In Teaching Mass Balances, Friction Factor And Mass Transfer Analysis, Keith Mciver

Theses and Dissertations

Many applications of chemical engineering principles are biomedical but traditional chemical engineering education does not focus on these applications. New laboratory experiments with hollow fiber blood oxygenators allow integration of concepts into already full programs. This work describes three new educational experiments that have been developed to introduce students to concepts of mass balances, mass transfer and momentum transfer as applied to a hollow fiber blood oxygenator. In addition, a new mass transfer correlation is presented for the Medtronic Affinity NT blood oxygenator, which has not been reported previously in the literature. Mass transfer of oxygen through the hollow fiber …

Method And Apparatus For Surface Chemical Functionalization Of Powders And Nanoparticles, Mary Gilliam, Susan Farhat, Graham Garner, Michael Magyar

Chemical Engineering Patents

A method and apparatus is provided for the modification of the surface chemistry of solid nano- and micro-particles in order to tailor the properties and functions of these particles. The method generally involves the generation of an atmospheric plasma glow discharge and energetic species that undergo chemical reaction with the surface of the primary particles. The process includes the generation of energetic species to initiate reaction, optional delivery of a precursor fluid, optional delivery of chemical species for grafting, and delivery of separated and de-agglomerated particles into the plasma discharge exiting the plasma generation chamber.

Development Of Experiments Involving Pharmaceutical Manufacturing Principles, Alexander Struck Jannini

Theses and Dissertations

Laboratory experiments were developed to incorporate pharmaceutical engineering concepts into Freshman-level engineering courses. The goal is to increase the interest of pharmaceutical engineering in students and provide the necessary background for more advanced courses in the field. The experiments can be used on an individual basis, or to be grouped into themes for more focused learning objectives. The laboratory experiments are available at the pharmaceutical knowledge and training website www.PharmaHUB.org under the Teaching Resources tab.

Spatial Stochastic Modeling Of The Erbb Receptor Family, Meghan Pryor

Chemical and Biological Engineering ETDs

ErbB transmembrane receptors are a family of 4 receptor tyrosine kinases that interact with one another through homo and heterodimer interactions. When these dimers form, the kinase domains on the receptor tails interact with one another, transphosphorylating one another, initiating a signal cascade. The signaling pathways these receptors participate in are responsible for many different cell functions including apoptosis, growth, and proliferation. The overexpression of these receptors has been linked to various forms of cancer, emphasizing the importance of understanding how these receptors interact with one another to trigger these cascades. Single Particle Tracking experiments have provided more precise and …

Evaluation Of Environmental Materials As Thermal Witness Materials, Shashank Vummidi Lakshman

Dissertations

New and complex energetic materials are under development for achieving tunable pyrotechnical events for applications such as neutralization of biological weapons, bunker busters and many others. To guide the development of hybrid materials, the pyrotechnical environment they produce requires higher degree of characterization i.e. good description of spatial and temporal temperature distribution.

Temperature measurements in pyrotechnical events are especially challenging, where the temperature of the environment rises more than 2000 K on microseconds to few milliseconds time scale. These environments produce high thermal stress where traditional sensors like thermocouples, optical pyrometers struggle to describe the dynamic changes in the environment. …

Novel Scrubbing Systems For Post-Combustion Co2 Capture And Recovery, Tripura Mulukutla

Dissertations

Power plant emissions of flue gas releases considerable CO₂ to the atmosphere; CO₂ is considered to be the main contributor to global warming. Several gas absorption techniques are being investigated to reduce the capital and operating costs for CO₂ capture from post-combustion flue gas. Conventional method of CO₂ capture by an aqueous solution of monoethanolamine (MEA) and its subsequent stripping in a separate tower with steam at 120°C, is a highly energy intensive process. The low partial pressure of CO₂ in the flue gas inhibits the application of CO₂-selective membranes unless methods are …

Ignition Mechanism In Nanocomposites Thermites, Rayon Williams

Dissertations

Nanocomposite thermites (n-thermites) have been actively investigated for a wide range of potential applications including propellants, explosives, and pyrotechnics. There have been several recent efforts aimed at understanding ignition mechanisms of nanocomposite reactive materials. Although significant progress has been made, ignition mechanisms remain elusive. At the same time, a robust ignition model is required to incorporate these materials in practical energetic formulations. A challenge of this effort is to describe the mechanisms of ignition of n-thermites prepared by Arrested Reactive Milling (ARM) with different stimuli, including heat, spark and impact and also develop a multi-step kinetic model describing different processes …

Synthesis And Characterization Of Metal-Based Reactive Powders, Yasmine Aly

Dissertations

Aluminum added to propellants, explosives, and pyrotechnics, boosts their energy density. Different approaches were investigated that could shorten aluminum ignition delays, increase combustion rates, and decrease the tendency of aluminum droplets to agglomerate. Here, Al-based reactive, mechanically milled materials are prepared and characterized.

For powders with Fe, Ni, or Zn additives, the particles consist of an aluminum matrix and inclusions of Fe, Ni, or Zn comprising 10 at % of the bulk composition. For additives of Ni and Zn, only short milling times can be used to prepare composites; intermetallic phases form at longer milling times. Thermogravimetric analysis shows selective …

The Photophysics Properties Of Lanthanide Luminescent Probes, Ke Li

Theses

A detailed study of the luminescence quantum yield, lifetimes and the number of water molecules coordinated to lanthanide luminescent probes based on biphenylyl-7-amino-4- methyl-2(1H)-quinolinon (Bi-cs124) derivatives have been carried out using a time- resolved fluorescence assay (TRFA). Bi-cs124 was conbined with different chelating agents, specifically diethylene triamine pentaacetic acid (DTPA), ethylene diamine tetraacetic acid (EDTA), ethylene glycol tetraacetic acid (EGTA), and 3,6,9,12-Tetrakis carboxymethyl)-3,6,9,12-tetraazatetradecane-1,14-dioic acid (TTHA). The results indicate that Bi-cs 124-TTHA has a longest lifetime and smallest number of coordinated water molecules because TTHA has larger number of chelating groups. The dependence of the luminescence lifetimes on the probes concentrations …

Preparation And Characterization Of Fast Dissolving Pullulan Films Containing Griseofulvin Nanoparticles For Bioavailability Enhancement, Zhelun Ma

Theses

The aim of this study is to enhance the bioavailability of griseofulvin, a model poorly water-soluble drug, via increasing drug dissolution rate through preparation of drug nanoparticle-laden, pullulan-based strip films. The work entails (i) wet-milling griseofulvin in a stirred media mill using pullulan (polymer) along with sodium dodecyl sulfate (surfactant) as stabilizers, (i i) preparing strip films by casting-drying a precursor suspension consisting of the mixture of the milled drug suspension and a film-forming pul l ul an–xanthan gum-glycerin solution, (iii) characterizing the suspensions and the films, and (iv) exploring the effects of film thickness, drug and xanthan gum loadings, …

Electrochemical Catalysis: A Dft Study, Li Li, Zi-Dong Wei

Journal of Electrochemistry

In this review, we focus on achievements in electro-catalysis based on the density function theory study. The relationships among the electrode potential, electronic structure of catalysts and electro-catalytic activity are summarized in three parts: the adsorption and desorption of species, electron transfer, and stability of catalysts. The electrode potential and the electronic structure (d-band center or Fermi (HOMO) energy) of catalysts significantly influence the formation, adsorption and desorption of surface species on electrode. The electro-catalytic activity can be improved by modulating the electrode potential and electronic structure of catalysts.

Synthesis Of Silver Nanoparticles Supported On Graphene Quantum Dots For Oxygen Reduction Reaction, Jian Ju, Wei Chen

Journal of Electrochemistry

Silver-based catalysts have been extensively investigated as the platinum substituted catalysts due to their high catalytic efficiency, low cost and long-term durability. In this study, the surfactant-free silver nanoparticles supported on graphene quantum dots were synthesized through a facile approach without addition of any other protecting ligands and reducing agents. The “surface-clean” silver nanoparticles had remarkable electrocatalytic performance towards oxygen reduction reaction (ORR) with the most efficient four-electron transfer process. Compared with commercial Pt/C catalyst, the hybrid nanoparticles showed comparable catalytic performance for ORR but much higher tolerance to methanol. Such silver nanoparticles supported on graphene quantum dots may have …

Effecting Of Dissolved Oxygen On Microbial Fuel Cells Based On Pseudomonas Aeruginosa, Chang-Li Cao, Li-Xiang Chen, Ran-Ran Wu, Ken-Lin Chang, Feng Zhao

Journal of Electrochemistry

In this work, the reaction between the electron shuttle secreted by Pseudomonas aeruginosa and anode was studied by measuring cyclic voltammogram and open circuit potential. The effect of dissolved oxygen on the oxidation reaction of anode was explored. It was demonstrated that the reaction was a diffusion-controlled and reversible process. The anode was a little affected when the dissolved oxygen of inocula was low (0 ~ 1.6 mg·L^-1). The polarization curves showed that the current output of microbial fuel cells decreased 7% with the impact of dissolved oxygen.

Recent Progress In The Mechanistic Understanding Of Formic Acid Oxidation On Pt Electrode, Jie Xu, Dao-Chuan Jiang, Dong Mei, Zheng-Da He, Yan-Xia Chen

Journal of Electrochemistry

This article reviews the recent progress in understanding of the mechanisms for formic acid oxidation on Pt electrode. There are two pathways for formic acid oxidation on Pt electrode: (1) Indirect Pathway through which HCOOH is oxidized to CO₂ through CO_ad intermediate. This pathway contributes only 1% of the total current; (2) Direct Pathway where HCOOH is oxidized directly to CO₂. The results from IR Spectroscopy, single-crystal electrochemistry and DFT calculation all support that the bridge-bonded formate is neither the intermediate of direct pathway nor the precursor for CO_ad formation in indirect pathway. Possible mechanism …

Electrocatalytic Oxidation Of Formate On Pd-Cu/C - Effect Of Dealloying Pretreatment, Kun Jiang, Ye Wang, Tao Lin, Wen-Bin Cai

Journal of Electrochemistry

Carbon supported highly dispersed Pd-Cu nanoalloy catalyst toward formate electrooxidation is prepared via one-pot synthesis by using ethylene glycol as the reducing agent and sodium citrate as the stabilizer. The as-prepared catalyst is structurally characterized by TEM and XRD. The Cu dealloyment is carried out through repetitive potential cycling of the Pd-Cu/C catalyst in an acidic solution. The dealloying effect on the performance of the Pd-Cu/C is investigated by using cyclic voltammetry and chronoamperometry, and the surface structural change of Pd-Cu/C is probed by in situ ATR-IR measurement. The results show that the as-prepared Pd-Cu/C processes a better long-term stability …