Chemical Engineering Commons^™

Electrocatalytic Study Of Pseudomonas Aeruginosa Bte-1 Strain, Ping Zhou, En-Ren Zhang, Li Zhou, Guo-Wang Diao, Jun-Le Niu

Journal of Electrochemistry

The aim of the present study is to investigate the electrocatalytic activity of electricity-producing Pseudomonas aeruginosa BTE-1 strain under anaerobic conditions. Pseudomonas aeruginosa BTE-1 was inoculated into anaerobic three-electrode electrochemical cells, and the electrocatalytic activity was measured at poised potentials. HPLC and cyclic voltammetry were used to detect potential electron mediators in solutions. Experimental results showed that no detectable pyocyanine was excreted by P. aeruginosa BTE-1 strain in the anaerobic electrochemcial cells, and P. aeruginosa BTE-1 exhibited direct electrocatalytic activity through the formation of biofilm on the electrode surface which was induced by the electron transfer from the cells of …

Synthesis And Electrochemical Performance Of Xlifepo4·Yli3V2(Po4)3 Composites, Ping-Ping Ma, Zhi-Jian Liu, Jian-Hua Xia, Yu Chen, Pu Hu, Zhi-Chao Lu, Ding-Guo Xia

Journal of Electrochemistry

A series of xLiFePO₄·yLi₃V₂(PO₄)₃ composites were systematically synthesized through solid state reactions by variations in the proportions of LiFePO₄ and Li₃V₂(PO₄)₃. The properties of the prepared compounds were investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM) and electrochemical measurements. The capacity of 162.7 mAh/g at 0.2 C rate was obtained with the relatively good cycle stability and good conductivity for 0.95LiFePO₄·0.05Li₃V₂(PO₄)₃ due to more uniformed distributed and smaller particle sizes.

Progress And Perspective Of Fuel Cell Technology, Ming Hou, Bao-Lian Yi

Journal of Electrochemistry

Fuel cell, a clean and high-efficiency electrochemical power source, has being paid much attention worldwide recent years. In this paper, the progress and perspective of fuel cell technology are elucidated in detail. Fuel cells have been applied in some special fields such as spacecraft, shuttle and submarines. However, in the areas of transportation, stationary station and portable power source, fuel cells are still under demonstration due to the durability and cost problems. The reliability and surrounding survivability of fuel cells should be enhanced in the special application. Meanwhile, the durability and cost of fuel cells are the main issues to …

Impact Of Internals On The Heat-Transfer Coefficient In A Bubble Column, Rahman S. Abdulmohsin, Muthanna H. Al-Dahhan

Chemical and Biochemical Engineering Faculty Research & Creative Works

The Effect of Heat Exchanging Internals on the Heat-Transfer Coefficient Has Been Investigated in a 0.19 M Diameter Bubble Column. an Air-Water System Was Used with Superficial Gas Velocities Varying from 3 to 20 Cm/s, Which Cover Both the Bubbly and Churn-Turbulent Flow Regimes. Internals Occluding 0% (Empty Column), 5% (Simulating Methanol Synthesis), and 22% (Simulating Fischer-Tropsch Synthesis) of the Column Cross-Sectional Area Were Implemented. a Fast Response Heat-Transfer Probe Was Utilized to Measure the Radial Profile of the Heat-Transfer Coefficient in the Fully Developed Flow Region. the Results Indicate that the Presence of a High Percentage of Internals Causes …

Influence Of Solid-Phase Wall Boundary Condition On Cfd Simulation Of Spouted Beds, Xingying Lan, Chunming Xu, Jinsen Gao, Muthanna H. Al-Dahhan

Chemical and Biochemical Engineering Faculty Research & Creative Works

The Influence of Solid-Phase Wall Boundary Condition in Terms of Specularity Coefficient and Particle-Wall Restitution Coefficient on the Flow Behavior of Spouted Beds Was Investigated using Two-Fluid Model Approach in the Computational Fluid Dynamics Software FLUENT 6.3. Parametric Studies of Specularity Coefficient and Particle-Wall Restitution Coefficient Were Performed to Evaluate their Effects on the Flow Hydrodynamics in Terms of Fountain Height, Spout Diameter, Pressure Drop, Local Voidage and Particles Velocity. the Numerical Predictions Were Compared with Available Experimental Data in the Literatures to Obtain the Suitable Values of Specularity Coefficient and Particle-Wall Restitution Coefficient for Spouted Beds. the Simulated Results …

Nanostructured Catalyst Materials For Next Generation Polymer Electrolyte Membrane (Pem) Fuel Cells, Wisam J. Khudhayer

Theses and Dissertations

Polymer electrolyte membrane (PEM) fuel cells are electrochemical energy conversion devices which have demonstrated great promise as future energy sources for electric vehicles, as they convert chemical energy to electrical energy with a significantly higher efficiency and lower environmental impact than in standard combustion processes. However, the commercialization of PEM fuel cells for transportation applications has been hindered by several factors such as high cost of Pt, low Pt utilization, poor long-term durability of the conventional PEM fuel cell catalyst (Pt nanoparticels supported on carbon black, Pt/C), and poor thermal and chemical stability of the electrocatalyst supports (carbon black). The …

Heat Transfer Coefficients In Mimicked Fischer-Tropsch Slurry Bubble Columns, Chengtian Wu, Muthanna H. Al-Dahhan

Chemical and Biochemical Engineering Faculty Research & Creative Works

To Provide More Support for Fischer-Tropsch (FT) Slurry Bubble Column Reactor Design, Scale-Up, and Performance, the Effects of Operating Conditions on the Heat Transfer Coefficients Were Investigated in a Mimicked FT Cold Flow System (Compressed Air:C 9-C 11:FT Catalyst Carrier). the Studied Operating Conditions Varied in Superficial Gas Velocity (Up to 0.3 M/s), Pressure (Up to 10 Bar), and Solids Concentration (Up to 25 Vol %). the Effects of These Variables on Heat Transfer Coefficients Are Discussed and Analyzed. the Increase in Pressure Tended to Reduce the Heat Transfer Coefficient, While the Increase in Solids Loading Enhanced the Heat Transfer …

Carbon Nanotubes Grown On Glass Fiber As A Strain Sensor For Real Time Structural Health Monitoring, Matthew Boehle, Qiong Jiang, Lingchuan Li, Alexandre Lagounov, Khalid Lafdi

Chemical and Materials Engineering Faculty Publications

In order to more effectively monitor the health of composite structures, a fuzzy fiber sensor has been developed. The fuzzy fiber is a bundle of glass fibers with carbon nanotubes or nanofibers (CNTs or CNFs) grown on the surface. The nanotube coating makes the fiber bundle conductive while the small conductive path increases sensitivity. The fuzzy fiber sensor can replace conventional metal foil strain gauges in composite applications. The electrical response of the sensor is monitored in real time to measure strain, vibration, cracking and delamination. Continuous monitoring provides instant notification of any problems. Implementation of this sensor network in …

Generalized Ellipsometry In-Situ Quantification Of Organic Adsorbate Attachment Within Slanted Columnar Thin Films, Keith B. Rodenhausen Jr., Daniel Schmidt, Tadas Kasputis, Angela K. Pannier, Eva Schubert, Mathias Schubert

Department of Chemical and Biomolecular Engineering: Faculty Publications

We apply generalized ellipsometry, well-known to be sensitive to the optical properties of anisotropic materials, to determine the amount of fibronectin protein that adsorbs onto a Ti slanted columnar thin film from solution. We find that the anisotropic optical properties of the thin film change upon organic adsorption. An optical model for ellipsometry data analysis incorporates an anisotropic Bruggeman effective medium approximation. We find that differences in experimental data from before and after fibronectin adsorption can be solely attributable to the uptake of fibronectin within the slanted columnar thin film. Simultaneous, in-situ generalized ellipsometry and quartz crystal microbalance measurements show …

Fabrication And Characterization Of Synthetic Substrates For Use In Rigidity Cell Culture Studies Of Valvular Interstitial Cells For Aortic Valve Tissue Engineering, Alexander T. Leonard

Chemical and Biological Engineering ETDs

More than 100,000 Americans each year undergo aortic valve (AV) replacement due to valve failure. An AV can become diseased, impairing the proper function of the valve. Common treatments for a defective valve are either replacement with a decellularized biologic or a synthetic valve. These treatments options are limited by short functional lifetime and thrombogenic surfaces. Tissue engineered heart valve will have the ability to integrate with the surrounding tissue as well as to repair and remodel. However, a greater understanding of valve cell biology is required to induce analogous tissue formation. A diseased valve is associated with stiffening of …

Single And Multiphase Mixing In Partially Filled Stirred Vessels, Shilan Motamedvaziri

Dissertations

In many industrial applications, mixing vessels have a liquid height-to-tank diameter ratio, H/T, equal to, or larger than 1. However, there are many instances where this ratio is lower than 1, as in all those cases in which the vessel is either emptied or filled. Even when H/T<1, sufficient agitation must still be provided in order to attain the desired process objectives. When the impeller submergence is reduced as a result of lowering the liquid level, the fluid dynamics of even a single-phase stirred liquid can become quite complex, with different regimes possibly existing depending on the geometric characteristics of the system (such as impeller clearance, liquid height, or liquid submergence above the impeller). The objectives of this work were to study in detail the hydrodynamic changes that occur when H/T is decreased, and to determine the minimum liquid levels and the critical impeller submergence for different impeller off-bottom distances, impeller diameters and agitation speeds where adequate mixing process can still be achieved, both in a single liquid phase and in solid-liquid suspensions.

Flat-bottomed, baffled vessels (5L, 12L, 20L and 170L) equipped with a single disk turbine (DT) of four different sizes placed at five different impeller off-bottom clearances were used here to study the system's hydrodynamics and related mixing phenomena. A number of experimental tools were used to analyze the systems under investigation, including: …

Hot-Melt Mixing Of Partially Miscible Active Pharmaceutical Ingredient-Polymer Mixtures, Min Yang

Dissertations

Solid dispersion/solution processes for producing pharmaceutical oral dosages such as hot-met extrusion (HME) have received increasing attention by industry and academe because they can enhance drugs’ solubility and even bioavailability to a great extent by converting drugs from crystalline to amorphous form. HME can be carried out at two process temperature regimes: one where T_process > T_m of the drug and the T_g of the polymer (or the T_m for the case of semi-crystalline polymers); the other at T_m > T_process > T_g (T_m for the case of semi-crystalline polymer). Processing below the drug’s …

Combustion Dynamics Of Individual Reactive Material Particles, Carlo Francisco Badiola

Theses

Metallic reactive powders are widely used as solid fuels, pyrotechnic materials, and components of enhanced blast explosives. Metals are attractive because of their high combustion enthalpies and temperatures. Quantitative descriptions of the combustion processes and mechanisms for both pure metal and composite particles are also desired for their proper implementation in specific applications. Among reactive metals, Al is used most widely and its combustion has been studied extensively. A recently developed experimental setup using laser-ignited metal powders enabled one to record optical signatures for time-resolved combustion instances for 2-25 µm diameter aluminum particles burning in different atmospheres. Individual particle diameters …

Preparation Of Different Polyamide Nanofiltration Membranes By Interfacial Polymerization And The Effect Of Post-Polymerization Treatment On Separation Performance, Yu Qin

Theses

Interfacial polymerization (IP) is a powerful technique for fabrication of thin film composite (TFC) membranes. In this study, polyamide nanofiltration (NF) composite membranes ware prepared by interfacial polymerization of polyethylenimine (PEI) or m-phenylene diamine (MPD) with isophthaloyl dichloride (IPD) on the surface of a porous polyethersulfone (PES) support. Concentrations of monomer reactants for this reaction were decided by equivalent weight ratio. A standard IP procedure was applied to successfully coat PES flat films. After preparation, three different post-polymerization treatments were employed and one optimal treatment was proven after membrane testing.

The TFC flat film membranes were characterized by nanofiltration of …

Carbon Dioxide Transfer Through Hollow Fiber Membranes, Pavlo Kostetskyy

Theses and Dissertations

Studies on absorption of CO2 into an aqueous solution using hydrophobic microporous hollow fiber membranes (HFM's) were performed. The use of HFM's for CO2 transfer could significantly improve the biomass growth rate in a photobioreactor for algal biofuel production. The membrane modules were operated in a sealed-end, parallel flow configuration. Several modules were constructed that ranged in interfacial surface area from 466 to 1397 m2/m3. The mass transfer coefficients were calculated based on a model of the system that included a prediction of the internal axial gas concentrations within the fiber lumen. This model was validated by measuring bulk gas …

Altering Iron Oxide Nanoparticle Surface Properties Induce Cortical Neuron Cytotoxicity, Christopher J. Rivet, Yuan Yuan, Diana Andra Borca-Tasciuc, Ryan J. Gilbert

Chemical and Biochemical Engineering Faculty Research & Creative Works

Superparamagnetic iron oxide nanoparticles, with diameters in the range of a few tens of nanometers, display the ability to cross the blood-brain barrier and are envisioned as diagnostic and therapeutic tools in neuro-medicine. However, despite the numerous applications being explored, insufficient information is available on their potential toxic effect on neurons. While iron oxide has been shown to pose a decreased risk of toxicity, surface functionalization, often employed for targeted delivery, can significantly alter the biological response. This aspect is addressed in the present study, which investigates the response of primary cortical neurons to iron oxide nanoparticles with coatings frequently …

Can Morphology Tailoring Improve The Open Circuit Voltage Of Organic Solar Cells?, Biswajit Ray, M. S. Lundstrom, Muhammad A. Alam

Birck and NCN Publications

While the effect of interfacial morphology on the short circuit current (I_SC) of organic photovoltaic devices (OPVs) is well known, its impact on open circuit voltage (V_OC) and fill-factor (FF) are less clear. Since the output power of a solar cell Pout = I_SCV_OCFF, such understanding is critical for designing high-performance, morphology-engineered OPVs. In this letter, we provide an explicit analytical proof that any effort to radically improve V_OC by tailoring bulk heterojunction morphology is futile, because any increase in ISC due to larger interface area is counterbalanced by corresponding increase …

Resolution Limit For Dna Barcodes In The Odijk Regime, Yanwei Wang, Wes F. Reinhart, Douglas R. Tree, Kevin D. Dorfman

Faculty Publications

We develop an approximation for the probability of optically resolving two fluorescent labels on the backbone of a DNA molecule confined in a nanochannel in the Odijk regime as a function of the fluorescence wavelength, channel size, and the properties of the DNA (persistence length and effective width). The theoretical predictions agree well with equivalent data produced by Monte Carlo simulations of a touching wormlike bead model of DNA in a high ionic strength buffer. Although the theory is only strictly valid in the limit where the effective width of the nanochannel is small compared with the persistence length of …

The Potential Of Industrial Waste And Agricultural Feedstock Towards Sustainable Biofuels Production: Techno-Economic And Environmental Impact Perspectives, Felix K. Adom

Dissertations, Master's Theses and Master's Reports - Open

This Ph.D. research is comprised of three major components; (i) Characterization study to analyze the composition of defatted corn syrup (DCS) from a dry corn mill facility (ii) Hydrolysis experiments to optimize the production of fermentable sugars and amino acid platform using DCS and (iii) Sustainability analyses. Analyses of DCS included total solids, ash content, total protein, amino acids, inorganic elements, starch, total carbohydrates, lignin, organic acids, glycerol, and presence of functional groups. Total solids content was 37.4% (± 0.4%) by weight, and the mass balance closure was 101%. Total carbohydrates [27% (± 5%) wt.] comprised of starch (5.6%), soluble …

Analysis Of The Penney-Ante Game Using Difference Equations: Development Of An Optimal And A Mixed-Strategies Protocol, Carl Barratt, Pauline Schwartz

Chemistry and Chemical Engineering Faculty Publications

Penney-Ante is a well known two-player (Player I and Player II) game based on an information paradox. We present a new approach, using difference-equations, to analyzing the outcome for each player. One strategy yields a winning outcome of 75% for Player II, the player playing second. The approach also permits investigation of non-optimal strategies, and demonstrates how mixing of such strategies can be used to tune the winning edge of either player. We generalize the analysis to accommodate the possibility of a biased coin.