Chemical Engineering Commons^™

Carbothermal Synthesis Of Titanium Oxycarbide As Electrocatalyst Support With High Oxygen Evolution Reaction Activity, Kan Huang, Yunfeng Li, Yangchuan Xing

Chemical and Biochemical Engineering Faculty Research & Creative Works

Carbothermal reduction of semiconducting TiO₂ into highly conductive titanium oxycarbide (TiOxCy) was investigated. The thermally produced uniform carbon layer on TiO₂ (Degussa P25) protects the TiO₂ nanoparticles from sintering and, at the same time, supplies the carbon source for doping TiO₂ with carbon. At low temperatures (e.g., 700 °C), carbon only substitutes part of the oxide and distorts the TiO₂ lattice to form TiO₂-xCx with only substitutional carbon. When the carbon-doped TiO₂ is annealed at a higher temperature (1100 °C), x-ray diffraction and x-ray photoelectron spectroscopy results showed that TiOxCy, a solid …

Picture Of A Chelate In Exchange: The Crystal Structure Of Nahodotma, A 'Semi'-Hydrated Chelate, Katherine M. Payne, Edward J. Valente, Silvio Aime, Mauro Botta, Mark Woods

Chemistry Faculty Publications and Presentations

Crystallography generally only provides static structural information. This can render it an ineffective technique for probing dynamic solution state processes. A crystal of HoDOTMA affords unique structures that effectively represent that of a lanthanide tetra-acetate chelate mid-way through the water exchange process.

Numerical Evaluation Of The Stability Of Stationary Points Of Index-2 Differential-Algebraic Equations: Applications To Reactive Flash And Reactive Distillation Systems, D. A. Harney, T. K. Mills, N. L. Book

Chemical and Biochemical Engineering Faculty Research & Creative Works

The dynamic behavior of many chemical processes can be represented by an index-2 system of differential-algebraic equations. This index can be reduced by differentiation, but unfortunately the index reduced systems are not guaranteed to possess the same stability characteristics as that of the original system. When the set of differential-algebraic equations can be written in Hessenberg form, the matrix pencil of the linearized system can be used to directly evaluate the stability of a steady state without the need for index reduction. Direct evaluations of stability of reactive flash and reactive distillation are presented. It is also shown that a …

A New Method For Online Flow Regime Monitoring In Bubble Column Reactors Via Nuclear Gauge Densitometry, Ashfaq Shaikh, Muthanna H. Al-Dahhan

Chemical and Biochemical Engineering Faculty Research & Creative Works

In the Current Work, Nuclear Gauge Densitometry (NGD), Which is Commercially Available and Industrially Used for Liquid/slurry Level Measurement and Control, Has Been Employed to Identify Fingerprints of the Prevailing Hydrodynamic Flow Regime. Experiments Were Performed using an Air-Water System in 0.1012. M Diameter and 1.2. M Long Bubble Column at Ambient Pressure. the Superficial Gas Velocities Were Varied from 1. Cm/s to 12. Cm/s with an Interval of 0.5. Cm/s Near Transition Region. the Flow Regime Boundaries Were Defined using the Conventional Methods of Flow Regime Demarcation Such as the Change in the Slope of the overall Gas Holdup …

Microkinetic Modeling And Analysis Of Ethanol Partial Oxidation And Reforming Reaction Pathways On Platinum At Short Contact Times, Maura A. Koehle

Master's Theses

No abstract provided.

Particle Shape Enhances Specificity Of Antibody-Displaying Nanoparticles, Sutapa Barua, Jin-Wook Yoo, Poornima Kolhar, Aditya Wakankar, Yatin R. Gokarn, Samir Mitragotri

Chemical and Biochemical Engineering Faculty Research & Creative Works

Monoclonal antibodies are used in numerous therapeutic and diagnostic applications; however, their efficacy is contingent on specificity and avidity. Here, we show that presentation of antibodies on the surface of nonspherical particles enhances antibody specificity as well as avidity toward their targets. Using spherical, rod-, and disk-shaped polystyrene nano- and microparticles and trastuzumab as the targeting antibody, we studied specific and nonspecific uptake in three breast cancer cell lines: BT-474, SK-BR-3, and MDA-MB-231. Rods exhibited higher specific uptake and lower nonspecific uptake in all cells compared with spheres. This surprising interplay between particle shape and antibodies originates from the unique …

Comparison Of A Sio2-Cao-Zno-Sro Glass Polyalkenoate Cement To Commercial Dental Materials: Glass Structure And Physical Properties, A. W. Wren, A. Coughlan, F. R. Laffir, Mark R. Towler

Chemical and Biochemical Engineering Faculty Research & Creative Works

Glass polyalkenoate cements (GPCs) have previously been considered for orthopedic applications. A Zn-GPC (BT 101) was compared to commercial GPCs (Fuji IX and Ketac Molar) which have a setting chemistry analogous to BT 101. Handling properties (working, T_w and setting, T_s times) for BT 101 were shorter than the commercial GPCs. BT 101 also had a higher setting exotherm (S_x - 34 °C) than the commercial GPCs (29 °C). The maximum strengths for BT 101, Fuji IX, and Ketac Molar were 75, 238, and 216 MPa (compressive, σ_c), and 34, 54, and 62 MPa (biaxial …

Separation Of Various Organic-Organic And Aqueous-Organic Solutions Via Pervaporation, John Tang

Dissertations

Pervaporation, an energy saving separation process, can be useful in pharmaceutical processing. However, the organic solvents involved in pharmaceutical product synthesis are chemically demanding; very few polymers are able to withstand them. An ideal membrane would be polymeric having a high thermal, chemical and mechanical stability. Such a membrane is made of a copolymer of polydimethyldioxole and tetrafluoroethylene known as PDD-TFE of the CMS-3 variety with a very high free volume. This novel membrane is used to separate a variety of organic-organic and aqueous-organic mixtures. An earlier study based on water-ethanol-isopropanol has shown evidence that the membrane selectivity may be …

Particle Engineering Via Surface Modification During Micronization For Pharmaceutical Applications, Xi Han

Dissertations

Improving the dissolution rate of Biopharmaceutics Classification System (BCS) class II drugs is an important research area. Micronization which can increase the specific surface area is a promising method to improve the dissolution rate. Micronization alone, however, can lead to downstream processing problems related to poor flow and dispersion properties. The importance of the flowability of pharmaceutical powders is well-documented in the literature. It is, therefore, important to develop a method that can simultaneously overcome these processing issues and allow for micronizing the API. In this work, dry particle coating technique is investigated in the context of micronizing API powders …

Mathematical Modeling Of Heavy Metals Diffusion And Removal From Cylindrical Cement Forms Coated With Bio-Film, Mojdeh Tabatabaie

Dissertations

A mathematical model is developed to predict bioleachi ng of heavy metals from long cylindrical shape cementitious samples. In this model, the metal concentration difference within the solid and its surface is considered as the main driving force for transport of metals to the surface of a sample at a given temperature and pressure. Fick’s first and second law are applied to explain the motion of contaminants in a long and uniform cylindrical solid. In addition, the model considers Michaelis-Menten type kinetics, a special case of the widely accepted Langmuir-Hinshelwood reaction mechanism, at the surface of the encapsulating cylinder. The …

Multifunctional Oxidation Electrocatalysts For Direct Alkaline Fuel Cells, Ulises Martinez

Chemical and Biological Engineering ETDs

The need for the development of new technologies to reduce our dependence on fossil fuels requires the combination of different energy sources such as wind, solar, nuclear as well as new energy storage and powering devices. Amongst these new technologies fuel cells are a promising technology capable of transforming chemical energy stored in fuels into electric power at higher efficiencies than combustion processes. However, the commercialization of fuel cells has been limited due to the high costs associated with electrocatalysts needed for the corrosive environments in which proton-exchange membrane fuel cells operate. Electrocatalysts for such fuel cells are based on …

Impact Of Carbon Support Chemistry, Morphology, And Structure On Platinum Catalyst Durability For Pemfc Applications, Anant Patel

Chemical and Biological Engineering ETDs

Polymer electrolyte membrane fuel cells are a promising alternative energy source, capable of being deployed as successful replacements in many stationary and mobile applications. These devices, however, lack durability, and this has become one of the limiting factors for commercialization. Many projects have focused on finding ways to improve their lifetimes, but few have tried to examine the underlying causes behind their corrosion. The goal of this project was to identify which parameters have a significant impact, both positive and negative, on PEMFC durability. To do this, three series of samples were analyzed using microscopic, spectroscopic, and electrochemical methods. Electron …

Life Cycle Assessment Of Dewatering Routes For Algae-Derived Biodiesel Processes, Daniel O'Connell

Theses and Dissertations

Biodiesel derived from algae is considered a sustainable fuel, but proper downstream processing is necessary to minimize the environmental footprint of this process. Algae is grown in dilute liquid cultures, and achieving the low water contents required for extraction represents one of the greatest challenges for the production of algae derived biodiesel. An analysis of the life cycle emissions associated with harvesting, dewatering, extraction, reaction, and product purification stages for algae biodiesel was performed. This "base case" found 10,500 kg of total emissions per t BD with 96% of those attributed to the spray dryer used for dewatering. Alternative cases …

Biological And Biomimetic Oxygen Electro-Reduction By Enzymes, Shayna Brocato

Chemical and Biological Engineering ETDs

Enzyme catalysts are a viable alternative to the traditional platinum based catalysts for the complete oxidation of complex fuels. Efficient oxidation of multi-carbon compounds, selective catalytic activity eliminating the need for fuel purification, and high performance under mild temperature and pH conditions make enzyme catalysts appealing for applications in vivo, implantable, and in vitro, portable energy sources. The full catalytic potential of enzymes can only be obtained if the full energy potential of a biofuel, complete oxidation to CO2, is obtained; this requires multiple reactions, i.e. multiple enzymes or an enzyme cascade. The efficiency of enzyme cascades improves with quaternary …

Flow In Thin Regions Bounded By Structured And Porous Surfaces : Applications To Load Bearings, Abishek Venkatakrishnan

Chemical and Biological Engineering ETDs

The effect of surface roughness on the load capacity and friction force of hydrodynamic bearings has received considerable interest from scientists and engineers. Surfaces of most engineered materials are textured at some level either deliberately to achieve some desired effect or produced by wear and friction of surfaces. This thesis analyses the effect of surface roughness and porosity on the load capacity of hydrodynamic bearings. The surface roughness is characterized by a single sinusoidal wave function. The implementation of sinusoidal roughness model is verified using a verification problem. Reynolds lubrication theory, derived from thin-region approximations of the Navier-Stokes equations, is …

An Investigation Of The Potential For And Application Of Life Cycle Analysis In The Pharmaceutical Industry, Michael Raymond

Theses and Dissertations

Life cycle assessment offers a unique opportunity to analyze emission reductions across all manufacturing sectors. However, few efforts have been made to apply this method to the pharmaceutical industry. The Toxic Release Inventory is a powerful tool to determine areas of high potential for emissions reductions in industry. When applied to the pharmaceutical industry and coupled with a life cycle assessment, areas for significant environmental improvement become apparent. By examining these trends and exploring a variety of emissions reductions techniques, life cycle emissions in these problem areas may be significantly reduced. These trends demonstrate that manufacture of virgin solvent and …

Organic Resin Laminate, Mary Gilliam, Koichi Higuchi, Masaaki Yamaya

Chemical Engineering Patents

An organic resin laminate comprising an organic resin substrate and a multilayer coating system thereon has UV-shielding property and high mar resistance. The multilayer coating system includes an outermost layer (I) resulting from plasma polymerization of an organosilicon compound, a lower layer (II) of a silicone coating composition comprising composite oxide nanoparticle dispersion, silicone resin, curing catalyst, and solvent, and optionally a bottom layer (III) of acrylic resin.

Exploring The Mechanisms Of Dna Hybridization On A Surface, Terry J. Schmitt, J Brandon Rogers, Thomas A. Knotts Iv

Faculty Publications

DNA microarrays are a potentially disruptive technology in the medical field, but their use in such settings is limited by poor reliability. Microarrays work on the principle of hybridization and can only be as reliable as this process is robust, yet little is known at the molecular level about how the surface affects the hybridization process. This work uses advanced molecular simulation techniques and an experimentally parameterized coarse-grain model to determine the mechanism by which hybridization occurs on surfaces. The results show that hybridization proceeds through a mechanism where the untethered (target) strand often flips orientation. For evenly lengthed strands, …

Hydrodynamics Of Pilot-Scale Bubble Columns: Effect Of Internals, Ahmed A. Youssef, Mohamed E. Hamed, Joshua T. Grimes, Muthanna H. Al-Dahhan, Milorad P. Duduković

Chemical and Biochemical Engineering Faculty Research & Creative Works

The Gas Holdup and Bubble Characteristics Are Key Parameters that Affect the Performance of Bubble Columns. an Experimental Study of the Effect of Heat Exchanging Internals on the Gas Holdup, Bubble Dynamics, and their Radial Profiles is Performed. an Air-Water System is Used in a Plexiglas Column 45 Cm (18 In.) in Diameter. Internals Configurations Mimicking Those Typical for the Liquid-Phase Methanol Synthesis and Fischer-Tropsch Process and Covering 5% and 25%, Respectively, of the Total Cross-Sectional Area of the Column, Are Investigated. High Superficial Gas Velocities that Fall within the Churn Turbulent Flow Regime, Which Are of Interest for Most …

Advanced Optimization Techniques For Monte Carlo Simulation On Graphics Processing Units, Eyad Hailat

Wayne State University Dissertations

The objective of this work is to design and implement a self-adaptive parallel GPU optimized Monte Carlo algorithm for the simulation of adsorption in porous materials. We focus on Nvidia's GPUs and CUDA's Fermi architecture specifically. The resulting package supports the different ensemble methods for the Monte Carlo simulation, which will allow for the simulation of multi-component adsorption in porous solids. Such an algorithm will have broad applications to the development of novel porous materials for the sequestration of CO2 and the filtration of toxic industrial chemicals.

The primary objective of this work is the release of a massively parallel …