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Chemical and Biochemical Engineering Faculty Research & Creative Works

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Articles 511 - 540 of 823

Full-Text Articles in Chemical Engineering

Fabrication Of Spherical Cao-Sro-Zno-Sio2 Particles By Sol-Gel Processing, Ill Yong Kim, Mark R. Towler, Anthony Wren, Chikara Ohtsuki Nov 2009

Fabrication Of Spherical Cao-Sro-Zno-Sio2 Particles By Sol-Gel Processing, Ill Yong Kim, Mark R. Towler, Anthony Wren, Chikara Ohtsuki

Chemical and Biochemical Engineering Faculty Research & Creative Works

This study was concerned with the fabrication of ceramic CaO-SrO-ZnO-SiO2 spherical particles, which are novel candidates for the glass phase in glass polyalkenoate cements (GPCs). GPCs made from these glasses have potential as bone cements because, unlike conventional GPCs, they do not contain aluminum ions, which inhibit the calcification of hydroxyapatite in the body. The glass phase of GPCs require a controllable glass morphology and particle size distribution. Sol-gel processing can potentially be used to fabricate homogenous ceramic particles with controlled morphology. However, a thorough study on preparation conditions of spherical CaO-SrO-ZnO-SiO2 particles by sol-gel processing has, to …

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Characterisation And Mechanical Testing Of Hydrothermally Treated Ha/Zro2 Composites, D. J. Curran, T. J. Fleming, G. Kawachi, C. Ohtsuki, Mark R. Towler Nov 2009

Characterisation And Mechanical Testing Of Hydrothermally Treated Ha/Zro2 Composites, D. J. Curran, T. J. Fleming, G. Kawachi, C. Ohtsuki, Mark R. Towler

Chemical and Biochemical Engineering Faculty Research & Creative Works

Hydrothermal treatment is traditionally employed to improve the sinterability of powder compacts by reducing porosity and increasing apparent density. The effect of hydrothermal treatment on green powder compacts has been assessed in order to better understand how treatment may affect the sinter ability of the bodies. Laboratory synthesized nano sized hydroxyapatite (HA) and a commercial zirconia (ZrO2) powder have been ball milled together to create composite mixtures containing 0-5 wt% ZrO2 loadings. Disc shaped bodies have been formed using uniaxial and subsequent isostatic pressure. The resultant coherent samples were subjected to hydrothermal treatment at either 120 or …

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Analysis Of Γ-Irradiated Synthetic Bone Grafts By ²⁹Si Mas-Nmr Spectroscopy, Calorimetry And Xrd, D. Boyd, S. Murphy, Mark R. Towler, A. W. Wren, S. Hayakawa Nov 2009

Analysis Of Γ-Irradiated Synthetic Bone Grafts By ²⁹Si Mas-Nmr Spectroscopy, Calorimetry And Xrd, D. Boyd, S. Murphy, Mark R. Towler, A. W. Wren, S. Hayakawa

Chemical and Biochemical Engineering Faculty Research & Creative Works

Ca-Sr-Zn-Si glasses have demonstrated excellent biocompatibility both in vitro using the MTT assay with L929 mouse fibroblast cells, and in vivo using healthy and ovariectomized female Wistar rats. However, the biological evaluation of the materials was performed on glass granules that were autoclaved, rather than γ-irradiated; the sterilisation procedure required prior to implantation of these materials in the human body. Given the fact that when a glass is exposed to ionizing radiation changes in its physical properties can take place, it is imperative to determine whether the structure of such glasses will be altered as a result of exposure to …

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Fabrication Of High-Capacity Biomolecular Carriers From Dispersible Single-Walled Carbon Nanotube-Polymer Composites, Pu Zhang, David B. Henthorn Oct 2009

Fabrication Of High-Capacity Biomolecular Carriers From Dispersible Single-Walled Carbon Nanotube-Polymer Composites, Pu Zhang, David B. Henthorn

Chemical and Biochemical Engineering Faculty Research & Creative Works

One of the most interesting applications for carbon nanotubes is as a support material for bioanalytical devices. in this work, we successfully used an ultraviolet light initiated "graft from" polymerization method to fabricate polymer functionalized carbon nanotubes (PFCNTs) with pendant chains of various functionalities, including poly (ethylene glycol) chains to boost dispersibility and pendant epoxy groups for protein conjugate sites. a model enzyme, alkaline phosphatase, was used to study biomolecule loading efficiency as well as the retention of enzyme activity. Samples with various ratios of the two monomers were fabricated to optimize their use in aqueous environments, and an optimal …

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Simple Agarose-Chitosan Gel Composite System For Enhanced Neuronal Growth In Three Dimensions, Zheng Cao, Ryan J. Gilbert, Wei He Oct 2009

Simple Agarose-Chitosan Gel Composite System For Enhanced Neuronal Growth In Three Dimensions, Zheng Cao, Ryan J. Gilbert, Wei He

Chemical and Biochemical Engineering Faculty Research & Creative Works

A simplified approach to increase neuronal attachment on an agarose hydrogel was proposed by blending agarose with another biocompatible polysaccharide, chitosan. The stiffness of the agarose gel was maintained despite the inclusion of chitosan, as determined by rheological tests. The structure of the blended hydrogels was characterized using light microscopy and scanning electron microscopy. An in vitro cell study revealed that the blends promoted neuron adhesion. The concentration of chitosan in the hydrogel had great influence on the morphology of neurons. An optimum range of chitosan concentration in agarose gel, to enhance neural cell attachment and differentiation, was identified based …

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The Effect Of Glass Synthesis Route On Mechanical And Physical Properties Of Resultant Glass Ionomer Cements, A. Wren, O. M. Clarkin, F. R. Laffir, C. Ohtsuki, I. Y. Kim, Mark R. Towler Oct 2009

The Effect Of Glass Synthesis Route On Mechanical And Physical Properties Of Resultant Glass Ionomer Cements, A. Wren, O. M. Clarkin, F. R. Laffir, C. Ohtsuki, I. Y. Kim, Mark R. Towler

Chemical and Biochemical Engineering Faculty Research & Creative Works

Glass ionomer cements (GICs) have potential orthopaedic applications. Solgel processing is reported as having advantages over the traditional melt-quench route for synthesizing the glass phase of GICs, including far lower processing temperatures and higher levels of glass purity and homogeneity. This work investigates a novel glass formulation, BT 101 (0.48 SiO2-0.36 ZnO-0.12 CaO-0.04 SrO) produced by both the melt-quench and the solgel route. The glass phase was characterized by X-ray diffraction (XRD) to determine whether the material was amorphous and differential thermal analysis (DTA) to measure the glass transition temperature (Tg). Particle size analysis (PSA) was …

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Methanol Electro-Oxidation On Pt-Ru Alloy Nanoparticles Supported On Carbon Nanotubes, Ang Li, Yangchuan Xing Sep 2009

Methanol Electro-Oxidation On Pt-Ru Alloy Nanoparticles Supported On Carbon Nanotubes, Ang Li, Yangchuan Xing

Chemical and Biochemical Engineering Faculty Research & Creative Works

Carbon nanotubes (CNTs) have been investigated in recent years as a catalyst support for proton exchange membrane fuel cells. Improved catalyst activities were observed and attributed to metal-support interactions. We report a study on the kinetics of methanol electro-oxidation on CNT supported Pt-Ru alloy nanoparticles. Alloy catalysts with different compositions, Pt 53Ru 47/CNT, Pt 69Ru 31/CNT and Pt 77Ru 23/CNT, were prepared and investigated in detail. Experiments were conducted at various temperatures, electrode potentials, and methanol concentrations. It was found that the reaction order of methanol electro-oxidation on the PtRu/CNT catalysts was consistent with what has been reported for PtRu …

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Comparison Of Failure Mechanisms For Cements Used In Skeletal Luting Applications, O. Clarkin, D. Boyd, Mark R. Towler Aug 2009

Comparison Of Failure Mechanisms For Cements Used In Skeletal Luting Applications, O. Clarkin, D. Boyd, Mark R. Towler

Chemical and Biochemical Engineering Faculty Research & Creative Works

Glass Polyalkenoate Cements (GPCs) based on strontium calcium zinc silicate (Sr-Ca-Zn-SiO2) glasses and low molecular weight poly (acrylic acid) (PAA) have been shown to exhibit suitable compressive strength (65 MPa) and flexural strength (14 MPa) for orthopaedic luting applications. In this study, two such GPC formulations, alongside two commercial cements (Simplex ® P and Hydroset™) were examined. Fracture toughness and tensile bond strength to sintered hydroxyapatite and a biomedical titanium alloy were examined. Fracture toughness of the commercial Poly(methyl methacrylate) cement, Simplex® P, (3.02 MPa m1/2) was superior to that of the novel GPC (0.36 MPa …

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Comparison Of An Experimental Bone Cement With A Commercial Control, Hydroset™, O. M. Clarkin, D. Boyd, S. Madigan, Mark R. Towler Jul 2009

Comparison Of An Experimental Bone Cement With A Commercial Control, Hydroset™, O. M. Clarkin, D. Boyd, S. Madigan, Mark R. Towler

Chemical and Biochemical Engineering Faculty Research & Creative Works

Glass polyalkenoate cements based on strontium calcium zinc silicate glasses (Zn-GPCs) and high molecular weight polyacrylic acids (PAA) (MW; 52,000-210,000) have been shown to exhibit mechanical properties and in vitro bioactivity suitable for arthroplasty applications. Unfortunately, these formulations exhibit working times and setting times which are too short for invasive surgical applications such as bone void filling and fracture fixation. In this study, Zn-GPCs were formulated using a low molecular weight PAA (MW; 12,700) and a modifying agent, trisodium citrate dihydrate (TSC), with the aim of improving the rheological properties of Zn-GPCs. These novel formulations were then compared with commercial …

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A Rapid Method For Flow-Ready Cylindrical Microchannel Fabrication, Kimberly H. Henthorn Jun 2009

A Rapid Method For Flow-Ready Cylindrical Microchannel Fabrication, Kimberly H. Henthorn

Chemical and Biochemical Engineering Faculty Research & Creative Works

Most current methods of microchannel fabrication are expensive and time consuming or result in noncylindrical channels, which is undesirable for many applications. A rapid inexpensive method for the fabrication of flow-ready cylindrical polymer microchannels from polydimethylsiloxane (PDMS) is presented here. In this method, cylindrical needles are used as molds for the channels and also function as flow delivery devices after fabrication. Validation of channel function and smoothness can be accomplished by comparing experimental data to theoretical models. One model was previously developed by the author to predict the incipient motion of a glass sphere in contact with a perfectly smooth …

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A Bipolar Clamp Mechanism For Activation Of Jak-Family Protein Tyrosine Kinases, Dipak Barua, James R. Faeder, Jason M. Haugh Apr 2009

A Bipolar Clamp Mechanism For Activation Of Jak-Family Protein Tyrosine Kinases, Dipak Barua, James R. Faeder, Jason M. Haugh

Chemical and Biochemical Engineering Faculty Research & Creative Works

Most cell surface receptors for growth factors and cytokines dimerize in order to mediate signal transduction. For many such receptors, the Janus kinase (Jak) family of non-receptor protein tyrosine kinases are recruited in pairs and juxtaposed by dimerized receptor complexes in order to activate one another by trans-phosphorylation. An alternative mechanism for Jak trans-phosphorylation has been proposed in which the phosphorylated kinase interacts with the Src homology 2 (SH2) domain of SH2-B, a unique adaptor protein with the capacity to homo-dimerize. Building on a rule-based kinetic modeling approach that considers the concerted nature and combinatorial complexity of modular protein domain …

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Novel Design Of Multiphase Reactors For Biomass-To-Liquid Synthesis, Ahmed Youssef, Milorad Dudukovic, Muthanna H. Al-Dahhan Mar 2009

Novel Design Of Multiphase Reactors For Biomass-To-Liquid Synthesis, Ahmed Youssef, Milorad Dudukovic, Muthanna H. Al-Dahhan

Chemical and Biochemical Engineering Faculty Research & Creative Works

Generation of liquid fuels from renewable sources such as biomass has been practiced since early 1900’s. In view of the skyrocketing oil prices and the depleting reserves of natural gas, it has gained further interest. The Fischer-Tropsch synthesis is one of the main processes considered. It involves the reaction of syngas in presence of a catalyst to produce liquid fuels. Syngas sources are numerous ranging from waste gasification, anaerobic digestion to clean coal. The reactor of choice for gas to liquid conversion is a slurry bubble column. Although, these multiphase reactors offer several advantages including good heat and mass transfer, …

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Biofilm Inhibitory Coatings Formulated From Glass Polyalkenoate Cement Chemistry: An Evaluation Of Their Adhesive Nature, A. Coughlan, D. Boyd, Mark R. Towler Mar 2009

Biofilm Inhibitory Coatings Formulated From Glass Polyalkenoate Cement Chemistry: An Evaluation Of Their Adhesive Nature, A. Coughlan, D. Boyd, Mark R. Towler

Chemical and Biochemical Engineering Faculty Research & Creative Works

Researchers evaluated the adhesive nature of the biofilm inhibitory coatings formulated from glass polyalkenoate cement (GPC) chemistry with the aim to establish the novel testing modality by modifying the conventional T-peel tests. Special consideration was given to determine the resistance of a bonded assembly of two adherents having at least one adherent flexible to quantify the bond between tape and a surgical metal substrate bonded by a luting GPC. The delaminated tape surface was examined by scanning electron microscopy (SEM) with an accelerating voltage of 20 K V to determine whether failure of the bond was adhesive of cohesive in …

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Extraction Of Alkaloids From Opium, Keith Tomazi Feb 2009

Extraction Of Alkaloids From Opium, Keith Tomazi

Chemical and Biochemical Engineering Faculty Research & Creative Works

A method for extracting at least one alkaloid from opium that includes dissolving opium in a solvent, heating the dissolved opium solution, cooling the dissolved opium solution, adjusting the pH of the dissolved opium solution with at least one first weak acid, filtering the dissolved opium solution to recover a filtrate; and then separating and purifying at least one alkaloid in the filtrate. Preferably, this includes an additional step of chilling the opium solution after adjusting the pH of the dissolved opium solution with at least one first acid. The preferred method for separating and purifying at least one alkaloid …

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Photopatternable Polymeric Membranes For Optical Oxygen Sensors, Raghu Ambekar, Jongwon Park, David Henthorn, Chang-Soo Kim Feb 2009

Photopatternable Polymeric Membranes For Optical Oxygen Sensors, Raghu Ambekar, Jongwon Park, David Henthorn, Chang-Soo Kim

Chemical and Biochemical Engineering Faculty Research & Creative Works

A new class of optical oxygen sensor that can be photopatternable by traditional UV lithography is presented. They are fabricated using photopatternable spin-on silicone (polydimethylsiloxane, PDMS) with oxygen sensitive luminescent dyes. It has a good adhesion property and can be applied on glass or on photopolymer (SU-8) without any additional surface treatments. The optimum mixture composition for patternable oxygen sensitive membranes is investigated and its optical properties are characterized. Proof-of-concepts for two applications, intensity-based oxygen sensing with SU-8 based structure and self-calibration fluidic oxygen sensor, are described. These photopatternable optical membranes will find many applications wherever small patterns of oxygen …

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Computed Tomographic Investigation Of The Influence Of Gas Sparger Design On Gas Holdup Distribution In A Bubble Column, B. C. Ong, P. Gupta, A. Youssef, M. (Muthanna) H. Al-Dahhan, M. P. Duduković Jan 2009

Computed Tomographic Investigation Of The Influence Of Gas Sparger Design On Gas Holdup Distribution In A Bubble Column, B. C. Ong, P. Gupta, A. Youssef, M. (Muthanna) H. Al-Dahhan, M. P. Duduković

Chemical and Biochemical Engineering Faculty Research & Creative Works

The Effect of Gas Sparger Design on the Gas Holdup Radial Profile in a Bubble Column (With a Diameter of 0.162 M) Has Been Studied using Γ-Ray Computed Tomography (CT). Six Different Configurations of Gas Spargers Were Examined, using an Air-Water System for Selected Superficial Gas Velocities from 2 Cm/s to 30 Cm/s, Covering the Homogeneous and Heterogeneous (Churn-Turbulent) Flow Regimes. Two Operating Pressures Were Used: 1 and 4 Atm. Differences Were Found between the Gas Holdup Distributions Produced by Different Spargers at Dimensionless Radii of R/R < 0.8 in the Central Region of the Column. the Cross and Single Nozzle Spargers Produced Closely Similar Gas Holdup Distributions, While the Perforated Plate Sparger Produced a Higher Gas Holdup When Compared to Other Spargers with the Same Percentage Open Area (POA). at 4 Atm, the Sparger Design Did Not Have a Significant Effect on the Gas Holdup Profiles, Compared to Atmospheric Pressure, Except for the Case of the Single-Hole Sparger, Which Was Found to Yield a Higher Gas Holdup. © 2009 American Chemical Society.

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Antibacterial Properties Of A Tri-Sodium Citrate Modified Glass Polyalkenoate Cement, A. W. Wren, D. Boyd, R. Thornton, J. C. Cooney, Mark R. Towler Jan 2009

Antibacterial Properties Of A Tri-Sodium Citrate Modified Glass Polyalkenoate Cement, A. W. Wren, D. Boyd, R. Thornton, J. C. Cooney, Mark R. Towler

Chemical and Biochemical Engineering Faculty Research & Creative Works

Primary deep infection following joint replacement surgery accounts for 7% of all revisions. Glass polyalkenoate cements (GPCs) have previously been shown to exhibit antibacterial properties. The present study had two objectives. The first was to determine if addition of tri-sodium citrate (TSC) to the powder phase of an Al-free GPC (0.04 SrO-0.12 CaO-0.36 ZnO-0.48 SiO2, by mole fraction) enhanced the resultant cement's antibacterial properties against three strains of bacteria that are commonly found in periprosthetic sites following total joint replacements (TJRs); namely, E. coli, B. fragilis, and S. epidermidis. Four cement sets were prepared, which contained 0 wt% TSC (control), …

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The Design By Molecular Dynamics Modeling And Simulations Of Porous Polymer Adsorbent Media Immobilized On The Throughpore Surfaces Of Polymeric Monoliths, E. Riccardi, J. C. Wang, A. I. Liapis Jan 2009

The Design By Molecular Dynamics Modeling And Simulations Of Porous Polymer Adsorbent Media Immobilized On The Throughpore Surfaces Of Polymeric Monoliths, E. Riccardi, J. C. Wang, A. I. Liapis

Chemical and Biochemical Engineering Faculty Research & Creative Works

Ion-exchange porous adsorbent media having intermediate and low surface densities of dextran polymer grafted on the surface of the through pores of polymeric monoliths are constructed and characterized by a molecular dynamic modeling and simulation approach that has also been shown to be effective in the construction and characterization of porous ion-exchange adsorbent media whose number of immobilized dextran polymer chains per unit surface area is high. the activation step that prepares the surface of the pores of the dextran polymer layer for the immobilization of the charged ligands insignificantly affected the pore structure of the dextran polymer layer, while …

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Preliminary Investigation Of Novel Bone Graft Substitutes Based On Strontium-Calcium-Zinc-Silicate Glasses, D. Boyd, G. Carroll, Mark R. Towler, C. Freeman, P. Farthing, I. M. Brook Jan 2009

Preliminary Investigation Of Novel Bone Graft Substitutes Based On Strontium-Calcium-Zinc-Silicate Glasses, D. Boyd, G. Carroll, Mark R. Towler, C. Freeman, P. Farthing, I. M. Brook

Chemical and Biochemical Engineering Faculty Research & Creative Works

Bone graft procedures typically require surgeons to harvest bone from a second site on a given patient (Autograft) before repairing a bone defect. However, this results in increased surgical time, excessive blood loss and a significant increase in pain. In this context a synthetic bone graft with excellent histocompatibility, built in antibacterial efficacy and the ability to regenerate healthy tissue in place of diseased tissue would be a significant step forward relative to current state of the art philosophies. We developed a range of calcium-strontium-zinc-silicate glass-based bone grafts and characterized their structure and physical properties, then evaluated their in vitro …

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Simulation Of Nanostructured Electrodes For Polymer Electrolyte Membrane Fuel Cells, Sanjeev M. Rao, Yangchuan Xing Dec 2008

Simulation Of Nanostructured Electrodes For Polymer Electrolyte Membrane Fuel Cells, Sanjeev M. Rao, Yangchuan Xing

Chemical and Biochemical Engineering Faculty Research & Creative Works

Aligned carbon nanotubes (CNTs) with Pt uniformly deposited on them are being considered in fabricating the catalyst layer of polymer electrolyte membrane (PEM) fuel cell electrodes. When coated with a proton conducting polymer (e.g., Nafion) on the Pt/CNTs, each Pt/CNT acts as a nanoelectrode and a collection of such nanoelectrodes constitutes the proposed nanostructured electrodes. Computer modeling was performed for the cathode side, in which both multicomponent and Knudsen diffusion were taken into account. the effect of the nanoelectrode lengths was also studied with catalyst layer thicknesses of 2, 4, 6, and 10 μm. It was observed that shorter lengths …

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Antibacterial Coatings For Medical Devices Based On Glass Polyalkenoate Cement Chemistry, A. Coughlan, D. Boyd, C. W.I. Douglas, Mark R. Towler Dec 2008

Antibacterial Coatings For Medical Devices Based On Glass Polyalkenoate Cement Chemistry, A. Coughlan, D. Boyd, C. W.I. Douglas, Mark R. Towler

Chemical and Biochemical Engineering Faculty Research & Creative Works

A biofilm is an accumulation of micro-organisms and their extracellular products forming a structured community on a surface. Biofilm formation on medical devices has severe health consequences as bacteria growing in this lifestyle are tolerant to both host defense mechanisms and antibiotic therapies. However, silver and zinc ions inhibit the attachment and proliferation of immature biofilms. The objective of this study is to evaluate whether it is possible to produce silver and zinc-containing glass polyalkenoate cement (GPC) coatings for medical devices that have antibacterial activity and which may therefore inhibit biofilm formation on a material surface. Two silver and zinc-containing …

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Effect Of Operating Pressure On The Extent Of Hysteresis In A Trickle Bed Reactor, Zeljko V. Kuzeljevic, Werner Van Der Merwe, Muthanna H. Al-Dahhan, Milorad P. Dudukovic, Willie Nicol Oct 2008

Effect Of Operating Pressure On The Extent Of Hysteresis In A Trickle Bed Reactor, Zeljko V. Kuzeljevic, Werner Van Der Merwe, Muthanna H. Al-Dahhan, Milorad P. Dudukovic, Willie Nicol

Chemical and Biochemical Engineering Faculty Research & Creative Works

The Dependence of Hydrodynamic Parameters, Such as Pressure Drop, on the Flow History of the Bed is Called Hysteresis. This Phenomenon is Most Commonly Associated with Changes of Flow Distribution and Flow Patterns with the Flow History. Many Studies Have Shown that Increased Operating Pressure Will Affect Flow Distribution and Wetting Efficiency; However, There Seems to Be No Study of the Effect of the Elevated Operating Pressure on the Extent of Hysteresis. in This Study, an Experimental Investigation of the Hysteresis in a High-Pressure Trickle Bed Has Been Performed. a Hysteresis Factor Has Been Introduced to Quantify the Extent of …

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Enhancing Water Removal From Whole Stillage By Enzyme Addition During Fermentation, Ana Beatriz Henriques, David B. Johnston, Muthanna H. Al-Dahhan Sep 2008

Enhancing Water Removal From Whole Stillage By Enzyme Addition During Fermentation, Ana Beatriz Henriques, David B. Johnston, Muthanna H. Al-Dahhan

Chemical and Biochemical Engineering Faculty Research & Creative Works

The Removal of Water from Coproducts in the Fuel Ethanol Process Requires a Significant Energy Input. in This Study, the Addition of Commercially Available Cell-Wall-Degrading Enzymes Was Investigated to Determine Whether or Not the Enzymes Could Reduce the Amount of Water Bound within the Wet Grains. This Would Have the Effect of Allowing More Water to Be Removed during Centrifugation, Reducing the Time and Energy Needed during the Drying Process. the Experiment Screened 15 Cell-Wall-Degrading Enzyme Preparations. a Significant Reduction in Water-Binding Capacity Was Found for a Number of Enzymes Tested in the Initial Screening. the Experiment Was Repeated and …

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Effect Of Ph On Ptru Electrocatalysts Prepared Via A Polyol Process On Carbon Nanotubes, Li Ren, Yangchuan Xing Jul 2008

Effect Of Ph On Ptru Electrocatalysts Prepared Via A Polyol Process On Carbon Nanotubes, Li Ren, Yangchuan Xing

Chemical and Biochemical Engineering Faculty Research & Creative Works

This paper reports a study on the pH effects on the PtRu nanoparticles synthesized in a polyol process that were deposited on carbon nanotubes (CNTs) by reducing metal salts using ethylene glycol at various pHs. It was found that the nanoparticle size, composition, and catalytic activity all were sensitive to pH. the nanoparticles decreased in size as the preparation pH increased from 1.6 to 10.0, with the largest size at 2.47 nm and the smallest at 1.13 nm. an exception was found for pH at 0.7, which resulted in an average size of only 1.01 nm. Preparation pH was found …

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Local Characteristics Of Hydrodynamics In Draft Tube Airlift Bioreactor, Hu Ping Luo, Muthanna H. Al-Dahhan Jun 2008

Local Characteristics Of Hydrodynamics In Draft Tube Airlift Bioreactor, Hu Ping Luo, Muthanna H. Al-Dahhan

Chemical and Biochemical Engineering Faculty Research & Creative Works

Airlift Column Reactors Have Been Widely Used in Bioprocesses. the Design, Scale-Up, and Performance Evaluation of Such Reactors All Require Extensive and Accurate Information About the Gas-Liquid Flow Dynamics, Particularly as Computational Fluid Dynamics (CFD) Has Become More Popular in the Last Decade. However, Due to the Limitation of Most Conventional Techniques for Gas-Liquid Flow Dynamics Measurement, Only Global Hydrodynamic Parameters (E.g., Cross-Sectionally Averaged Liquid Circulation Velocity, overall Gas Holdup, and overall Mass Transfer Rate) Have Been Extensively Studied. the Local Flow Characteristics (E.g., the Macro-Mixing and the Turbulence Intensity) Remain Unclear. in This Study, We Use the Computer Automated …

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Encapsulation And Extended Release Of Anti-Cancer Anastrozole By Stealth Nanoparticles, Kumkum Sarkar, Hu Yang Jun 2008

Encapsulation And Extended Release Of Anti-Cancer Anastrozole By Stealth Nanoparticles, Kumkum Sarkar, Hu Yang

Chemical and Biochemical Engineering Faculty Research & Creative Works

To improve delivery efficiency of anastrozole, we applied dendrimer-based stealth nanoparticles to encapsulate anastrozole to formulate stealth anastrozole nanoparticles. This work demonstrated that stealth nanoparticles composed of a PAMAM dendrimers core and a PEG layer could encapsulate anastrozole, hence causing improved water solubility of anastrozole. Anastrozole encapsulation depended on concentration of stealth nanoparticles and generation of dendrimer. The extended release of anastrozole was achieved. We envisioned that this highly structurally adaptable stealth nanoparticle could be further biofunctionalized to construct a targeted therapeutic delivery system for breast cancer treatment.

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Agarose And Methylcellulose Hydrogel Blends For Nerve Regeneration Applications, Benton C. Martin, Eric J. Minner, Sherri L. Wiseman, Rebecca L. Klank, Ryan J. Gilbert Jun 2008

Agarose And Methylcellulose Hydrogel Blends For Nerve Regeneration Applications, Benton C. Martin, Eric J. Minner, Sherri L. Wiseman, Rebecca L. Klank, Ryan J. Gilbert

Chemical and Biochemical Engineering Faculty Research & Creative Works

Trauma sustained to the central nervous system is a debilitating problem for thousands of people worldwide. Neuronal regeneration within the central nervous system is hindered by several factors, making a multi-faceted approach necessary. Two factors contributing to injury are the irregular geometry of injured sites and the absence of tissue to hold potential nerve guides and drug therapies. Biocompatible hydrogels, injectable at room temperature, that rapidly solidify at physiological temperatures (37°C) are beneficial materials that could hold nerve guidance channels in place and be loaded with therapeutic agents to aid wound healing. Our studies have shown that thermo reversible methylcellulose …

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Bubble Dynamics Investigation In A Slurry Bubble Column, Chengtian Wu, Kelsey Suddard, Muthanna H. Al-Dahhan May 2008

Bubble Dynamics Investigation In A Slurry Bubble Column, Chengtian Wu, Kelsey Suddard, Muthanna H. Al-Dahhan

Chemical and Biochemical Engineering Faculty Research & Creative Works

The Application of Four-Point Optical Probe Has Been for the First Time Extended to a Slurry System in a 10.2-Cm ID Column. Bubble Dynamics (Local Gas Holdup, Bubble Chord Length, Bubble Velocity, Bubble Frequency, and Specific Interfacial Area) Were Investigated using an Air-Water-Catalyst System under Atmospheric Pressure. with an Increase in Solids Loading, the Local Gas Holdup, Specific Interfacial Area, and Bubble Frequency Decreased, While the Bubble Velocity Changed Slightly. Bubble Chord Length Increased Noticeably, and the Bubble Chord Length Distribution Spread More Widely at High Solids Loading. It Has Also Been Found that the Probe Orientation is Important for …

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Effect Of Shear On Performance And Microbial Ecology Of Continuously Stirred Anaerobic Digesters Treating Animal Manure, Rebecca A. Hoffmann, Marcelo L. Garcia, Mehul Veskivar, Khursheed Karim, Muthanna H. Al-Dahhan, Largus T. Angenent May 2008

Effect Of Shear On Performance And Microbial Ecology Of Continuously Stirred Anaerobic Digesters Treating Animal Manure, Rebecca A. Hoffmann, Marcelo L. Garcia, Mehul Veskivar, Khursheed Karim, Muthanna H. Al-Dahhan, Largus T. Angenent

Chemical and Biochemical Engineering Faculty Research & Creative Works

We Determined the Effect of Different Mixing Intensities on the Performance, Methanogenic Population Dynamics, and Juxtaposition of Syntrophic Microbes in Anaerobic Digesters Treating Cow Manure from a Dairy Farm. Computer Automated Radioactive Particle Tracking in Conjunction with Computational Fluid Dynamics Was Performed to Quantify the Shear Levels Locally. Four Continuously Stirred Anaerobic Digesters Were Operated at Different Mixing Intensities of 1,500, 500, 250, and 50 Revolutions Per Min (RPM) over a 260-Day Period at a Temperature of 34 ± 1°C. Animal Manure at a Volatile Solids (VS) Concentration of 50 G/L Was Fed into the Digesters Daily at Five Different …

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Comparison Of An Experimental Bone Cement With Surgical Simplex® P, Spineplex® And Cortoss®, D. Boyd, Mark R. Towler, A. Wren, O. M. Clarkin Apr 2008

Comparison Of An Experimental Bone Cement With Surgical Simplex® P, Spineplex® And Cortoss®, D. Boyd, Mark R. Towler, A. Wren, O. M. Clarkin

Chemical and Biochemical Engineering Faculty Research & Creative Works

Conventional polymethylmethacrylate (PMMA) cements and more recently Bisphenol-a-glycidyl dimethacrylate (BIS-GMA) composite cements are employed in procedures such as vertebroplasty. Unfortunately, such materials have inherent drawbacks including, a high curing exotherm, the incorporation of toxic components in their formulations, and critically, exhibit a modulus mismatch between cement and bone. The literature suggests that aluminum free, zinc-based glass polyalkenoate cements (Zn-GPC) may be suitable alternative materials for consideration in such applications as vertebroplasty. This paper examines one formulation of Zn-GPC and compares its strengths, modulus, and biocompatibility with three commercially available bone cements, Spineplex®, Simplex® P and Cortoss®. The setting times indicate …

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