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Chemical and Biochemical Engineering Faculty Research & Creative Works

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Articles 541 - 570 of 823

Full-Text Articles in Chemical Engineering

The Processing, Mechanical Properties And Bioactivity Of Strontium Based Glass Polyalkenoate Cements, Anthony Wren, Daniel Boyd, Mark R. Towler Apr 2008

The Processing, Mechanical Properties And Bioactivity Of Strontium Based Glass Polyalkenoate Cements, Anthony Wren, Daniel Boyd, Mark R. Towler

Chemical and Biochemical Engineering Faculty Research & Creative Works

The suitability of zinc-based glass polyalkenoate cements (GPCs) for use in orthopaedics can be improved by the substitution of strontium into the glass phase which should impart improved radiopacity and bone forming properties to the cements without retarding strength. The purpose of this research was to produce novel GPCs based on calcium-strontium-zinc-silicate glasses and to evaluate their mechanical properties and biocompatibility with the ultimate objective of developing a new range of cements for skeletal applications. Three glass compositions, based on incremental substitutions of strontium for calcium, were synthesized; BT100 (0.16CaO, 0.36ZnO, 0.48SiO2), BT101 (0.04SrO, 0.12CaO, 0.36ZnO, 0.48SiO2 …


Electrochemical Durability Of Carbon Nanotubes At 80 °C, Liang Li, Yangchuan Xing Mar 2008

Electrochemical Durability Of Carbon Nanotubes At 80 °C, Liang Li, Yangchuan Xing

Chemical and Biochemical Engineering Faculty Research & Creative Works

Carbon nanotubes (CNTs) have been studied as an alternative catalyst support in polymer electrolyte membrane (PEM) fuel cells. Recent studies showed that CNTs appear to be more resistant to electrochemical corrosion than carbon black (CB). in a previous study, we have demonstrated the room temperature durability of multiwalled CNTs in both non-catalyzed and catalyzed electrochemical oxidations. This paper is to report results conducted at 80 °C-an operational temperature of PEM fuel cells. It was found that multiwalled CNTs are still more resistant than CB at the elevated temperature. However, the electrochemical oxidation rate is more rapid than that at the …


Macro-Mixing In A Draft-Tube Airlift Bioreactor, Hu Ping Luo, Muthanna H. Al-Dahhan Mar 2008

Macro-Mixing In A Draft-Tube Airlift Bioreactor, Hu Ping Luo, Muthanna H. Al-Dahhan

Chemical and Biochemical Engineering Faculty Research & Creative Works

Airlift Reactors Are Pneumatically Agitated Reactors that Have Been Widely Used in Industries, Particularly in Bioprocesses. Extensive Studies About the Flow Dynamics in Airlift Column Reactors Exist; However, Most of These Studies Have Focused on Global Hydrodynamic Parameters using Conventional Techniques. the Local Flow Characteristics, such as the Macro-Mixing and the Turbulence Intensity, Are Crucial for Reliable Design and Scale-Up, and They Remain Unclear. This Work Focuses on Studying the Macro-Mixing in a Draft-Tube Airlift Bioreactor Utilizing an Advanced Flow Dynamic Measurement Technique, Computer Automated Radioactive Particle Tracking (CARPT). True Residence Time Distribution Analyses for the overall Column as Well …


Computational Models Of Tandem Src Homology 2 Domain Interactions And Application To Phosphoinositide 3-Kinase, Dipak Barua, James R. Faeder, Jason M. Haugh Mar 2008

Computational Models Of Tandem Src Homology 2 Domain Interactions And Application To Phosphoinositide 3-Kinase, Dipak Barua, James R. Faeder, Jason M. Haugh

Chemical and Biochemical Engineering Faculty Research & Creative Works

Intracellular signal transduction proteins typically utilize multiple interaction domains for proper targeting, and thus a broad diversity of distinct signaling complexes may be assembled. Considering the coordination of only two such domains, as in tandem Src homology 2 (SH2) domain constructs, gives rise to a kinetic scheme that is not adequately described by simple models used routinely to interpret in vitro binding measurements. To analyze the interactions between tandem SH2 domains and bisphosphorylated peptides, we formulated detailed kinetic models and applied them to the phosphoinositide 3-kinase p85 regulatory subunit/platelet-derived growth factor β-receptor system. Data for this system from different in …


Modeling Of Trickle-Bed Reactors With Exothermic Reactions Using Cell Network Approach, Jing Guo, Yi Jiang, Muthanna H. Al-Dahhan Feb 2008

Modeling Of Trickle-Bed Reactors With Exothermic Reactions Using Cell Network Approach, Jing Guo, Yi Jiang, Muthanna H. Al-Dahhan

Chemical and Biochemical Engineering Faculty Research & Creative Works

One-Dimensional (1D) and Two-Dimensional (2D) Cell Network Models Were Developed to Simulate the Steady-State Behavior of Trickle-Bed Reactors Employed for the Highly Exothermic Hydrotreating of Benzene. the Multiphase Mass Transfer-Reaction Model and Novel Solution Method Are Discussed in This Report. the 1D Model Was Shown to Satisfactorily Simulate the Axial Temperature Field Observed Experimentally for Multiphase Flow with Exothermic Reactions. the 2D Reactor Modeling Provided Valuable Information About Local Hot Spot Behavior within the Multiphase Reactor, Identifying Situations in Which Hot Spots May Form. the Model Took into Consideration the Heterogeneous Nature of Liquid Distribution, Including Radial Liquid Maldistribution and …


The Role Of Sr²⁺ On The Structure And Reactivity Of Sro-Cao-Zno-Sio2 Ionomer Glasses, Daniel Boyd, Mark R. Towler, Sally Watts, Robert G. Hill, Anthony W. Wren, Owen M. Clarkin Feb 2008

The Role Of Sr²⁺ On The Structure And Reactivity Of Sro-Cao-Zno-Sio2 Ionomer Glasses, Daniel Boyd, Mark R. Towler, Sally Watts, Robert G. Hill, Anthony W. Wren, Owen M. Clarkin

Chemical and Biochemical Engineering Faculty Research & Creative Works

The suitability of Glass Polyalkenoate Cements (GPCs) for use in orthopaedics is retarded by the presence in the glass phase of aluminum, a neurotoxin. Unfortunately, the aluminum ion plays an integral role in the setting process of GPCs and its absence is likely to hinder cement formation. However, the authors have previously shown that aluminum free GPCs may be formulated based on calcium zinc silicate glasses and these novel materials exhibit significant potential as hard tissue biomaterials. To further improve their potential and given that Strontium (Sr) based drugs have had success in the treatment of osteoporosis, the authors have …


Tem Analysis Of Apatite Surface Layers Observed On Zinc Based Glass Polyalkenoate Cements, D. Boyd, Mark R. Towler, A. W. Wren, O. M. Clarkin, D. A. Tanner Feb 2008

Tem Analysis Of Apatite Surface Layers Observed On Zinc Based Glass Polyalkenoate Cements, D. Boyd, Mark R. Towler, A. W. Wren, O. M. Clarkin, D. A. Tanner

Chemical and Biochemical Engineering Faculty Research & Creative Works

The amorphous nature and composition of the surface apatite layers observed on glass polyalkenoate cements based on zinc silicate glasses (Zn-GPCs) after immersion in simulated body fluid (SBF) have been analyzed by the transmission electron microscopy (TEM). TEM was conducted using a JEOL JEM-2011 electron microscope operated at an accelerating voltage of 200 kV. The composition elements of the surface layer indicated the presence of calcium, phosphorous, zinc, and strontium within the amorphous structure. This composition, in particular the inclusion of Zn in the structure, indicates the lack of crystallinity associated with the formation of the apatite layers observed on …


Digestion Of Sand-Laden Manure Slurry In An Upflow Anaerobic Solids Removal (Uasr) Digester, Khursheed Karim, Rebecca Hoffmann, M. (Muthanna) H. Al-Dahhan Feb 2008

Digestion Of Sand-Laden Manure Slurry In An Upflow Anaerobic Solids Removal (Uasr) Digester, Khursheed Karim, Rebecca Hoffmann, M. (Muthanna) H. Al-Dahhan

Chemical and Biochemical Engineering Faculty Research & Creative Works

Studies on the Performance of a Laboratory Scale Up flow Anaerobic Solids Removal (UASR) Digester Were Carried Out using Sand-Laden Cow Manure Slurries Having Total Solids (TS) Concentration as 50 and 100 G/l. Hydraulic Retention Time (HRT) Was Maintained as 32.4 Days, Which Resulted in the Volatile Solids (VS) Loading Rates of 1 and 1.64 G/l D. the UASR System Was Designed to Remove Sand from the Manure Slurry, While Anaerobically Digesting Biodegradable Solids Inside a Single Reactor. to Enhance the Contact of Microorganisms and Substrate, the Liquor from the Top of the Digester Was Recirculated through the Bed of …


Bubble Velocity, Size, And Interfacial Area Measurements In A Bubble Column By Four-Point Optical Probe, Junli Xue, Muthanna H. Al-Dahhan, M. P. Dudukovic, R. F. Mudde Feb 2008

Bubble Velocity, Size, And Interfacial Area Measurements In A Bubble Column By Four-Point Optical Probe, Junli Xue, Muthanna H. Al-Dahhan, M. P. Dudukovic, R. F. Mudde

Chemical and Biochemical Engineering Faculty Research & Creative Works

The Four-Point Optical Probe is Applied in a Bubble Column with an Air-Water System to Investigate the Bubble Properties (Local Gas Holdup, Velocity, Chord Length, Specific Interfacial Area, and Frequency) over a Range of Gas Superficial Velocities. Both Bubbles Moving Upward and Downward Are Recorded and Measured as Opposed to Only Upward Bubbles Measured and Reported in Other Studies Involving Probes. the Probe Worked Efficiently in Both Bubbly Flow and Highly Churn-Turbulent Flow at Very High Superficial Gas Velocities. Bubble Properties at the Conditions of Churn-Turbulent Flow Are Obtained and Investigated for the First Time. the Changes in the Bubble …


A Comparison Of Alternating Minimization And Expectation Maximization Algorithms For Single Source Gamma Ray Tomography, R. Varma, S. Bhusarapu, J. A. O'Sullivan, M. (Muthanna) H. Al-Dahhan Jan 2008

A Comparison Of Alternating Minimization And Expectation Maximization Algorithms For Single Source Gamma Ray Tomography, R. Varma, S. Bhusarapu, J. A. O'Sullivan, M. (Muthanna) H. Al-Dahhan

Chemical and Biochemical Engineering Faculty Research & Creative Works

Lange and Carson (1984 J. Comput. Assist. Tomogr. 8 306-16) Defined Image Reconstruction for Transmission Tomography as a Maximum Likelihood Estimation Problem and Derived an Expectation Maximization (EM) Algorithm to Obtain the Maximum Likelihood Image Estimate. However, in the Maximization Step or M-Step of the EM Algorithm, an Approximation is Made in the Solution Which Can Affect the Image Quality, particularly in the Case of Domains with High Attenuating Material. O'Sullivan and Benac (2007 IEEE Trans. Med. Imaging 26 283-97) Reformulated the Maximum Likelihood Problem as a Double Minimization of an I-Divergence to Obtain a Family of Image Reconstruction Algorithms, …


Effect Of Hydrodynamic Multiplicity On Trickle Bed Reactor Performance, Werner Van Der Merwe, Willie Nicol, Muthanna H. Al-Dahhan Jan 2008

Effect Of Hydrodynamic Multiplicity On Trickle Bed Reactor Performance, Werner Van Der Merwe, Willie Nicol, Muthanna H. Al-Dahhan

Chemical and Biochemical Engineering Faculty Research & Creative Works

Multiple Hydrodynamic States in Trickle Bed Reactors Have Been the Subject of Numerous Hydrodynamic Investigations. the Extent of Variation in the Hydrodynamic Parameters (Like Holdup and Pressure Drop) is Large and This Variation Can Be Expected to Have a Significant Impact on the Conversion in a Reaction System. This Study Presents Reaction Data for Α-Methyl Styrene Hydrogenation in a Trickle Bed Reactor over a Range of Conditions that Include Gas and Liquid Limitations. It is Seen that Liquid Flow Rate Variation Induced Hysteresis Has a Large Impact on the Conversion. for Gas-Limited Reactions, the Upper Branch of the Pressure Drop …


Effect Of Sparger Design On Hydrodynamics Of A Gas Recirculation Anaerobic Bioreactor, Rajneesh Varma, Muthanna H. Al-Dahhan Dec 2007

Effect Of Sparger Design On Hydrodynamics Of A Gas Recirculation Anaerobic Bioreactor, Rajneesh Varma, Muthanna H. Al-Dahhan

Chemical and Biochemical Engineering Faculty Research & Creative Works

The Effects of Sparger Design and Gas Flow Rate On, Gas Holdup Distribution and Liquid (Slurry) Recirculation Velocity Have Been Studied in a Surrogate Anaerobic Bioreactor Used for Treating Bovine Waste with a Conical Bottom Mixed by Gas Recirculation. a Single Orifice Sparger (SOS) and a Multi-Orifice Ring Sparger (MORS) with the Same Orifice Open Area and Gas Flow Rates (Hence the Same Process Power Input) Are Compared in This Study. the Advanced Non-Invasive Techniques of Computer Automated Tomography (CT) and Computer Automated Radioactive Particle Tracking (CARPT) Were Employed to Determine Gas Holdup, Liquid Recirculation Velocity, and the Poorly Mixed …


Numerical Simulation Of Gas-Solid Dynamics In A Circulating Fluidized-Bed Riser With Geldart Group B Particles, S. Vaishali, Shantanu Roy, Satish Bhusarapu, M. (Muthanna) H. Al-Dahhan, M. P. Dudukovic Dec 2007

Numerical Simulation Of Gas-Solid Dynamics In A Circulating Fluidized-Bed Riser With Geldart Group B Particles, S. Vaishali, Shantanu Roy, Satish Bhusarapu, M. (Muthanna) H. Al-Dahhan, M. P. Dudukovic

Chemical and Biochemical Engineering Faculty Research & Creative Works

Circulating Fluidized-Bed (CFB) Risers with Geldart Group B Particles Have Found Significant Application in Combustion Reactions. the Present Work Attempts to Study the Solids Flow Dynamics in a CFB Riser that is Operated with Group B Particles, using Computational Fluid Dynamics (CFD) Techniques. the Key Feature in the Present Study is that the Various Closure Schemes in the CFD Model Have Been Evaluated Against Data from Non-Invasive Experimental Techniques: Computer Automated Radioactive Particle Tracking (CARPT) for Solids Velocity Field and Computed Tomography (CT) for Solids Holdup. Since Solids Flow in a Riser is Multiscale in Character, in Addition to the …


Phase Transformations Of Calcium Phosphates Formed In Wet Field Environments, O. M. Clarkin, Mark R. Towler, G. M. Insley, M. E. Murphy Oct 2007

Phase Transformations Of Calcium Phosphates Formed In Wet Field Environments, O. M. Clarkin, Mark R. Towler, G. M. Insley, M. E. Murphy

Chemical and Biochemical Engineering Faculty Research & Creative Works

The crystal phase and morphology of calcium phosphate salts precipitated in a wet field environment at temperatures between 30 and 70 °C and pHs between 3 and 8 were examined. Dicalcium Phosphate Dihydrate (DCPD) was the most prevalent phase precipitated. Using accelerated ageing study techniques, precipitates studied were aged, under dry conditions at 50 °C for 8 and 16 days, before being re-examined using XRD, FTIR and SEM techniques. DCPD was found to be most stable when precipitated at 40 °C and 5 pH. Considerably more phase transformation to Octacalcium Phosphate (OCP), Amorphous Calcium Phosphate (ACP) and Hydroxyapatite (HA) was …


Prediction Of The Kolmogorov Entropy Derived From Computed Tomography Data In A Bubble Column Operated Under The Transition Regime And Ambient Pressure, Stoyan Nedeltchev, Ashfaq Shaikh, Muthanna H. Al-Dahhan Oct 2007

Prediction Of The Kolmogorov Entropy Derived From Computed Tomography Data In A Bubble Column Operated Under The Transition Regime And Ambient Pressure, Stoyan Nedeltchev, Ashfaq Shaikh, Muthanna H. Al-Dahhan

Chemical and Biochemical Engineering Faculty Research & Creative Works

The Kolmogorov Entropy (KE) Algorithm Was Successfully Applied to Single Source Γ-Ray Computed Tomography (CT) Data Measured by Three Scintillation Detectors in a 0.162 M-ID Bubble Column Equipped with a Perforated Plate Distributor (163 Holes X ∅ 1.32. 10-3 M). the Aerated Liquid Height Was Set at 1.8 M. Dried Air Was Used as a Gas Phase, While Therminol LT (PL = 886 Kg M-3, ΜL = 0.88.10-3 Pa S, Σ = 17.10-3 N M-1) Was Used as a Liquid Phase. at Ambient Pressure, the Superficial Gas Velocity, ΜG, Was Increased …


Mesophilic Digestion Kinetics Of Manure Slurry, Khursheed Karim, K. Thomas Klasson, Sadie R. Drescher, Whitney Ridenour, Abhijeet P. Borole, Muthanna H. Al-Dahhan Sep 2007

Mesophilic Digestion Kinetics Of Manure Slurry, Khursheed Karim, K. Thomas Klasson, Sadie R. Drescher, Whitney Ridenour, Abhijeet P. Borole, Muthanna H. Al-Dahhan

Chemical and Biochemical Engineering Faculty Research & Creative Works

Anaerobic Digestion Kinetics Study of Cow Manure Was Performed at 35°C in Bench-Scale Gas-Lift Digesters (3.78 L Working Volume) at Eight Different Volatile Solids (VS) Loading Rates in the Range of 1.11-5.87 G L-1 Day-1. the Digesters Produced Methane at the Rates of 0.44-1.18 L L-1 Day-1, and the Methane Content of the Biogas Was Found to Increase with Longer Hydraulic Retention Time (HRT). based on the Experimental Observations, the Ultimate Methane Yield and the Specific Methane Productivity Were Estimated to Be 0.42 L CH4 (G vs. Loaded)-1 and 0.45 L CH …


Influence Of Two Changes In The Composition Of An Acrylic Bone Cement On Its Handling, Thermal, Physical, And Mechanical Properties, G. Lewis, J. Xu, S. Madigan, Mark R. Towler Aug 2007

Influence Of Two Changes In The Composition Of An Acrylic Bone Cement On Its Handling, Thermal, Physical, And Mechanical Properties, G. Lewis, J. Xu, S. Madigan, Mark R. Towler

Chemical and Biochemical Engineering Faculty Research & Creative Works

This study is a contribution to the growing body of work on the influence of changes in the composition of an acrylic bone cement on various properties of the curing and cured material. The focus is on one commercially-available acrylic bone cement brand, Surgical Simplex®P, and three variants of it and a series of properties, namely, setting time, maximum exotherm temperature, activation energy and frequency factor for the polymerization reaction, diffusion coefficient for the uptake of phosphate buffered saline, at 37°C, ultimate compressive strength (UCS), plane-strain fracture toughness, fatigue life (under fully-reversed tension-compression stress), hardness (H) and elastic modulus (both …


A Chemical Engineering Laboratory Over Distributed Control And Measurement Systems, Jing Guo, David Kettler, Muthanna H. Al-Dahhan Aug 2007

A Chemical Engineering Laboratory Over Distributed Control And Measurement Systems, Jing Guo, David Kettler, Muthanna H. Al-Dahhan

Chemical and Biochemical Engineering Faculty Research & Creative Works

Remote Control of Lab Apparatus Via the Internet Allows Flexible Scheduling of Experiments and Exercises. This Paper Presents a Novel Application of Computers and Internet Technology in Chemical Engineering Education that Highlights Interactive Learning for an Undergraduate Course in Online Measurement and Control. the Proposed Client-Server Architecture Can Be Adapted to Drive Different Kinds of Devices and Can Be Easily Expanded. the Developed Online Laboratory Has Been Tested by Many Students using Different Connections and Operating Conditions. This Internet-Based Solution Can Improve Undergraduate Engineering Education in a Conventional Unit Operation Laboratory. as an Example, the Application of Remote Experiments to …


Vibrational Modes Of ⁴He And H₂ Gases Adsorbed On Carbon Nanotubes, Silvina M. Gatica, Angela D. Lueking, W. Milton Cole, Gerald D. Mahan Aug 2007

Vibrational Modes Of ⁴He And H₂ Gases Adsorbed On Carbon Nanotubes, Silvina M. Gatica, Angela D. Lueking, W. Milton Cole, Gerald D. Mahan

Chemical and Biochemical Engineering Faculty Research & Creative Works

We present calculations of the breathing mode phonon frequencies of 4He and H2 physically adsorbed on the outside surface of one or more carbon nanotubes. Two geometries are considered. The first is a single, isolated nanotube, upon which the gas is adsorbed as a commensurate phase. The second is a quasi-one-dimensional "groove" phase nestled between two nanotubes. While the computed breathing mode frequencies depend on nanotube radius and the adsorbate, in general, they are of the same order of magnitude as those of the bare nanotubes.


Influence Of Acid Washing On The Surface Morphology Of Ionomer Glasses And Handling Properties Of Glass Ionomer Cements, C. M. Crowley, J. Doyle, Mark R. Towler, N. Rushe, S. Hampshire Aug 2007

Influence Of Acid Washing On The Surface Morphology Of Ionomer Glasses And Handling Properties Of Glass Ionomer Cements, C. M. Crowley, J. Doyle, Mark R. Towler, N. Rushe, S. Hampshire

Chemical and Biochemical Engineering Faculty Research & Creative Works

Acid washing is known to influence the handling properties of ionomer glasses used in glass ionomer cements due to the production of an ion depleted zone on the surface of the glass particles. The influence of acid washing on the particle size distribution and surface area of four glasses was examined by scanning electron microscopy (SEM), particle size analysis (PSA) and accelerated surface area porosimetry (ASAP) and the working and setting times of cements, produced from the glasses, correlated to changes in surface morphology. A linear relationship was found between the specific surface area of acid-washed SiO2-Al2 …


Using A Fiber-Optic Probe For The Measurement Of Volumetric Expansion Of Liquids, Sean G. Mueller, Jay R. Werber, Muthanna H. Al-Dahhan, Milorad P. Dudukovic Jun 2007

Using A Fiber-Optic Probe For The Measurement Of Volumetric Expansion Of Liquids, Sean G. Mueller, Jay R. Werber, Muthanna H. Al-Dahhan, Milorad P. Dudukovic

Chemical and Biochemical Engineering Faculty Research & Creative Works

A Fiber-Optic Probe is Developed for the Fast, In-Situ Measurement of Volumetric Expansion of Multiphase and Multicomponent Systems. an Experiment with the Binary Mixtures of CO2-Toluene and CO2-Ethanol Was Conducted to Demonstrate the Usefulness of the Fiber-Optic Probe in Accurately Tracking the Isothermal Volumetric Expansion as a Function of Pressure. in the 1-L Autoclave that Has Been Used, the Probe Was Shown to Detect the Liquid Level Height within a Precision of 0.35% of the Total Height of the Vessel. the Results for the Volumetric Expansion of Toluene and Ethanol with CO2 Correlate Well with …


Measuring Gas-Liquid Distribution In A Pilot Scale Monolith Reactor Via An Industrial Tomography Scanner (Its), M. (Muthanna) H. Al-Dahhan, A. Kemoun, A. R. Cartolano, S. Roy, R. Dobson, J. Williams Jun 2007

Measuring Gas-Liquid Distribution In A Pilot Scale Monolith Reactor Via An Industrial Tomography Scanner (Its), M. (Muthanna) H. Al-Dahhan, A. Kemoun, A. R. Cartolano, S. Roy, R. Dobson, J. Williams

Chemical and Biochemical Engineering Faculty Research & Creative Works

An Industrial Tomography Scanner (ITS) Was Designed and Developed to Study and Quantify the Phase Distribution in a Two-Phase Flow Pilot Scale Monolith Reactor that Was 24 In. (0.60 M) in Diameter and 192 In. (4.9 M) in Height. the Monolith Reactor Was Operated Co-Current Up-Flow in the Taylor Flow Regime with Water as the Liquid Phase and Air as the Gas Phase. the Cross-Sectional Holdup Distributions Were Measured at Three Axial Elevations. the Operating Conditions Were Selected to Bracket Commercial Operating Conditions for Fixed Bed Monolithic Reactor Systems. the Results Show that its Can Capture the Flow Features in …


Preliminary Work On The Development Of A Novel Detection Method For Osteoporosis, P. Moran, Mark R. Towler, S. Chowdhury, J. Saunders, M. J. German, N. S. Lawson, H. M. Pollock, I. Pillay, D. Lyons Jun 2007

Preliminary Work On The Development Of A Novel Detection Method For Osteoporosis, P. Moran, Mark R. Towler, S. Chowdhury, J. Saunders, M. J. German, N. S. Lawson, H. M. Pollock, I. Pillay, D. Lyons

Chemical and Biochemical Engineering Faculty Research & Creative Works

Osteoporosis affects both the organic and mineral phases of bone resulting in a decrease in resistance to fracture. Dual x-ray absorptiometry (DEXA) scans are used for diagnosing osteoporosis, which is conventionally characterized by a decrease in mineral density. Unfortunately, some patients who suffer osteoporotic fractures have normal bone density, because both the organic and the mineral phase are affected. However, there are currently no methods of evaluating the health of the organic phase. Patients undergoing treatment for osteoporosis have reported hardening of their fingernails. As the properties of nail and bone may be linked in a comparable, measurable way, this …


Pt-Ru Nanoparticles Supported On Carbon Nanotubes As Methanol Fuel Cell Catalysts, Liang Li, Yangchuan Xing May 2007

Pt-Ru Nanoparticles Supported On Carbon Nanotubes As Methanol Fuel Cell Catalysts, Liang Li, Yangchuan Xing

Chemical and Biochemical Engineering Faculty Research & Creative Works

Bimetallic Pt - Ru alloy catalysts have been demonstrated to be more active than pure Pt catalysts in the electrooxidation of methanol. We report here a study on Pt - Ru nanoparticle catalysts supported on sonochemically functionalized carbon nanotubes. the catalysts were prepared by directly reducing the corresponding salts, K2PtCl4 and K 2RuCl5, in an ethylene glycol aqueous solution containing dispersed carbon nanotubes. Three catalysts of different Pt to Ru atomic ratios, namely, Pt53Ru47, Pt69Ru31, and Pt77Ru23, were prepared for investigation of the compositional effects, It was shown that highly dispersed bimetallic Pt - Ru alloy nanoparticles with no agglomeration …


Raman Spectroscopy Of The Human Nail: A Potential Tool For Evaluating Bone Health?, Mark R. Towler, A. Wren, N. Rushe, J. Saunders, N. M. Cummins, P. M. Jakeman May 2007

Raman Spectroscopy Of The Human Nail: A Potential Tool For Evaluating Bone Health?, Mark R. Towler, A. Wren, N. Rushe, J. Saunders, N. M. Cummins, P. M. Jakeman

Chemical and Biochemical Engineering Faculty Research & Creative Works

Dual X-ray absorptiometry (DEXA) is the current gold standard for the diagnosis of osteoporosis. However, patients can suffer osteoporotic fractures despite normal bone mineral density, partly because of unmeasured influences of both the protein and mineral phases of bone that are affected in osteoporosis. There is currently no clinically applicable method of evaluating the health of the protein phase. The proteins in human nail (keratin) and bone (collagen) require sulphation and disulphide bond (S-S) formation for structural integrity and disorders of either sulphur metabolism or cystathione beta-synthase can lead to structural abnormalities in these tissues. Raman protein spectra provide a …


Commensurate Phases Of Gases Adsorbed On Carbon Nanotubes, Angela D. Lueking, W. Milton Cole May 2007

Commensurate Phases Of Gases Adsorbed On Carbon Nanotubes, Angela D. Lueking, W. Milton Cole

Chemical and Biochemical Engineering Faculty Research & Creative Works

A study is presented of the nature of ordered phases of various gases adsorbed on an isolated carbon nanotube. Because the spacing between neighboring adsorption sites depends on the tube's radius R, the equilibrium structure of the ground state is predicted to differ from that observed on planar graphite. Results for this structure are presented for the inert gases and hydrogen as a function of R for zigzag nanotubes.


Wetting Kinetics Of A Thin Film Evaporating In Air, S. Saritha, Partho Neogi Jan 2007

Wetting Kinetics Of A Thin Film Evaporating In Air, S. Saritha, Partho Neogi

Chemical and Biochemical Engineering Faculty Research & Creative Works

The conservation equation and the equations of motion are solved for a case where a thin liquid film moves out of a slot onto a horizontal surface. The liquid is allowed to evaporate into air. The evaporation process is taken to be isothermal. Lubrication theory approximation is used where only the tangential velocity and its dependence only in the normal direction are considered. The dynamics of thin films includes the use of disjoining pressure for a pure liquid and where there is a dissolved polymer. The results show that evaporation is quicker than film thinning such that a spreading regime …


Heat Transfer Coefficients In A High-Pressure Bubble Column, Chengtian Wu, Muthanna H. Al-Dahhan, Anand Prakash Jan 2007

Heat Transfer Coefficients In A High-Pressure Bubble Column, Chengtian Wu, Muthanna H. Al-Dahhan, Anand Prakash

Chemical and Biochemical Engineering Faculty Research & Creative Works

Time-Averaged Local Heat Transfer Coefficients Were Studied in a 0.16 M Inner Diameter High-Pressure Air-Water Bubble Column. the Effects of the Superficial Gas Velocity (Up to 0.30 M/s), Pressure (Up to 10 Bar), Probe Position, and Probe Orientation Were Investigated. the Heat Transfer Coefficients Increased with Superficial Gas Velocity, and the Values in the Center of the Column Were 9-16% Greater Than Those Near the Wall Region under Atmospheric Pressure (1 Bar). with the Increase in Pressure, the Heat Transfer Coefficients Decreased Due to Combined Effects of Bubble Size Decreasing, Gas Holdup Increasing, and Bubble Number Increasing. the Heat Transfer …


Gas-Liquid Mass Transfer In A High Pressure Bubble Column Reactor With Different Sparger Designs, Lu Han, Muthanna H. Al-Dahhan Jan 2007

Gas-Liquid Mass Transfer In A High Pressure Bubble Column Reactor With Different Sparger Designs, Lu Han, Muthanna H. Al-Dahhan

Chemical and Biochemical Engineering Faculty Research & Creative Works

The Gas-Liquid Mass Transfer in a 0.162 M High-Pressure Stainless-Steel Bubble Column Was Investigated using Three Different Gas Sparger Designs. an Oxygen-Enriched-Air Dynamic Method and an Optical Oxygen Probe Technique Were Implemented to Measure K1 a Values in the Bubble Column Reactor. using the Interfacial Area (A) Values Measured by a Four-Point Optical Probe Technique at Similar Conditions (Xue, 2004), the K1 Values Were Estimated. Axial Dispersion Model (ADM) and Continuous Stirred Tank Reactor (CSTR) Model Were Used to Calculate K1 a as a Fitted Parameter with the Measured Data. the ADM Gave Better Fits to the Experimental Data Than …


Deposition Of Metallic Nanoparticles On Carbon Nanotubes Via A Fast Evaporation Process, Guoqiang Ren, Yangchuan Xing Nov 2006

Deposition Of Metallic Nanoparticles On Carbon Nanotubes Via A Fast Evaporation Process, Guoqiang Ren, Yangchuan Xing

Chemical and Biochemical Engineering Faculty Research & Creative Works

A new technique was developed for the deposition of colloidal metal nanoparticles on carbon nanotubes. It involves fast evaporation of a suspension containing sonochemically functionalized carbon nanotubes and colloidal nanoparticles. It was demonstrated that metallic nanoparticles with different sizes and concentrations can be deposited on the carbon nanotubes with only a few agglomerates. the technique does not seem to be limited by what the nanoparticles are, and therefore would be applicable to the deposition of other nanoparticles on carbon nanotubes. PtPd and CoPt3 alloy nanoparticles were used to demonstrate the deposition process. It was found that the surfactants used to …