Open Access. Powered by Scholars. Published by Universities.®

Engineering Commons™

Open Access. Powered by Scholars. Published by Universities.®

Chemical Engineering

PDF

Series

1999

Institution
Keyword
Publication

Articles 1 - 30 of 61

Full-Text Articles in Engineering

Modeling And Simulation Of The Dynamic Behavior Of Monoliths: Effects Of Pore Structure From Pore Network Model Analysis And Comparison With Columns Packed With Porous Spherical Particles, Athanasios I. Liapis, J. J. Meyers, Orrin K. Crosser Dec 1999

Modeling And Simulation Of The Dynamic Behavior Of Monoliths: Effects Of Pore Structure From Pore Network Model Analysis And Comparison With Columns Packed With Porous Spherical Particles, Athanasios I. Liapis, J. J. Meyers, Orrin K. Crosser

Chemical and Biochemical Engineering Faculty Research & Creative Works

A mathematical model is presented that could be used to describe the dynamic behavior, scale-up, and design of monoliths involving the adsorption of a solute of interest. The value of the pore diffusivity of the solute in the pores of the skeletons of the monolith is determined in an a priori manner by employing the pore network modeling theory of Meyers and Liapis [J. Chromatogr. A, 827 (1998) 197 and 852 (1999) 3]. The results clearly show that the pore diffusion coefficient, D(mp), of the solute depends on both the pore size distribution and the pore connectivity, n(T), of the …

Go to article

Lead-Free Interconnection For Electronic Devices, Ravi F. Saraf Dec 1999

Lead-Free Interconnection For Electronic Devices, Ravi F. Saraf

Department of Chemical and Biomolecular Engineering: Patents

An electronic device that is equipped with a plurality of bonding pads positioned on the device for making electrical interconnections and electrically conductive composite bumps adhered to the bonding pads wherein the bumps are formed of a composite material consisting of a thermoplastic polymer and at least about 30 volume percent of conductive metal particles based on the total volume of the metal particles and the thermoplastic polymer. The present invention is also directed to a method of making electrical interconnections to an electronic device by pressing a plurality of composite bumps of a polymeric based material against a substrate …

Go to article

Method For Providing Discharge Protection Or Shielding, Ravi F. Saraf Dec 1999

Method For Providing Discharge Protection Or Shielding, Ravi F. Saraf

Department of Chemical and Biomolecular Engineering: Patents

Electrostatic discharge protection or electromagnetic interference shielding is provided by applying a composition comprising a thermoset or thermoplastic polymeric matrix, and a conductive filler component, where said filler component comprises electrically conductive particles and at least one conducting polymer to a dielectric substrate.

Go to article

Double Twist In Helical Polymer "Soft" Crystals, Christopher Y. Li, Stephen Z. D. Cheng, Jason J. Ge, Feng Bai, John Z. Zhang, Ian K. Mann, Frank W. Harris, Lang-Chy Chien, Donghang Yan, Tianbai He, Bernard Lotz Nov 1999

Double Twist In Helical Polymer "Soft" Crystals, Christopher Y. Li, Stephen Z. D. Cheng, Jason J. Ge, Feng Bai, John Z. Zhang, Ian K. Mann, Frank W. Harris, Lang-Chy Chien, Donghang Yan, Tianbai He, Bernard Lotz

College of Polymer Science and Polymer Engineering

In natural and synthetic materials having non-racemic chiral centers, chirality and structural ordering each play a distinct role in the formation of ordered states. Configurational chirality can be extended to morphological chirality when the phase, structures possess low liquid crystalline order. In the crystalline states the crystallization process suppresses the chiral helical morphology due to strong ordering interactions, In this Letter, we report the first observation of helical single lamellar crystals of synthetic non-racemic chiral polymers. Experimental evidence shows that the molecular chains twist along both the long and short axes of the helical lamellar crystals, which is the first …

Go to article

Simulation And Density Functional Study Of A Simple Membrane Separating Two Restricted Primitive Model Electrolytes, Richard L. Rowley, Dezso Boda, Douglas Henderson, Stefan Sokolowski Nov 1999

Simulation And Density Functional Study Of A Simple Membrane Separating Two Restricted Primitive Model Electrolytes, Richard L. Rowley, Dezso Boda, Douglas Henderson, Stefan Sokolowski

Faculty Publications

A simple membrane, supporting charge densities on its inner and outer surfaces, is considered. In addition to the electrostatic potential, the membrane interacts with the surrounding fluid by a short range van der Waals-like potential. The fluid beyond the outer surface is a three-component restricted primitive electrolyte consisting of two cations and one anion. The membrane is impermeable to one of the cations so that the fluid in the membrane and beyond the inner surface is a two-component restricted primitive electrolyte. We use Monte Carlo simulations and density functional theory to study the density profiles of the electrolyte and the …

Go to article

Method Of Destroying Hazardous Organic Compounds, Dibakar Bhattacharyya, Susan Mawhinney Nov 1999

Method Of Destroying Hazardous Organic Compounds, Dibakar Bhattacharyya, Susan Mawhinney

Chemical and Materials Engineering Faculty Patents

The present invention relates to a method of destroying hazardous vapor phase or aqueous phase organic compound(s) by providing a polymeric siloxane based solvent in a vessel and adding the hazardous organic compound(s) and ozone to the solvent. The solvent may also comprise a mixture of polymeric siloxane based solvent and fluorinated hydrocarbon solvent.

Go to article

Inside-Out Crosslinked And Commercial-Scale Hydrogels, And Sub-Macromolecular Selective Purification Using The Hyrdogels, William H. Velander, Kevin E. Van Cott Nov 1999

Inside-Out Crosslinked And Commercial-Scale Hydrogels, And Sub-Macromolecular Selective Purification Using The Hyrdogels, William H. Velander, Kevin E. Van Cott

Department of Chemical and Biomolecular Engineering: Patents

Relating to chromatographic processes and ion-exchange and affinity matrices, a spatial installation method for a bifunctional reagent that crosslinks and/or activates a polymer matrix is disclosed, with inside-outside installation of a bifunctional reagent on and within a polymer matrix. The polymer matrix is cellulose, agarose, or chitosan particles. The installation may be followed by inside-outside ligand attachment, by further reacting the matrix with a ligand or ionic group so that a higher concentration of ligand or ionic moiety occurs on the intra-particle volume than the outer matrix surface.

Go to article

Helical Single-Lamellar Crystals Thermotropically Formed In A Synthetic Nonracemic Chiral Main-Chain Polyester, Christopher Y. Li, Donghang Yan, Stephen Z. D. Cheng, Feng Bai, Jason J. Ge, Bret H. Calhoun, Tianbai He, Liang-Chy Chien, Frank W. Harris, Bernard Lotz Nov 1999

Helical Single-Lamellar Crystals Thermotropically Formed In A Synthetic Nonracemic Chiral Main-Chain Polyester, Christopher Y. Li, Donghang Yan, Stephen Z. D. Cheng, Feng Bai, Jason J. Ge, Bret H. Calhoun, Tianbai He, Liang-Chy Chien, Frank W. Harris, Bernard Lotz

College of Polymer Science and Polymer Engineering

Phase structures and transformation mechanisms of nonracemic chiral biological and synthetic polymers are fundamentally important topics in understanding their macroscopic responses in different environments. It has been known for many years that helical structures and morphologies can exist in low-ordered chiral liquid crystalline (LC) phases. However, when the chiral liquid crystals form highly ordered smectic liquid crystal phases, the helical morphology is suppressed due to the crystallization process. A double-twisted morphology has been observed in many liquid crystalline biopolymers such as dinoflaggellate chromosomes (in Prorocentrum micans) in an in vivo arrangement. Helical crystals grown from solution have been reported in …

Go to article

Methods Of Fabricating Plasticized, Antiplasticized And Crystalline Conducting Polymers And Precursors Thereof, Ravi F. Saraf Oct 1999

Methods Of Fabricating Plasticized, Antiplasticized And Crystalline Conducting Polymers And Precursors Thereof, Ravi F. Saraf

Department of Chemical and Biomolecular Engineering: Patents

Methods of forming materials containing precursors to electrically conductive polymers and electrically conductive polymers are described which have a high degree of crystallinity. The high degree of crystallinity is achieved by preparing the materials under conditions which provide a high degree of mobility to the polymer molecules permitting them to associate with one another to form a crystalline state. High levels of electrical conductivity are achieved in in the electrically conductive materials without stretch orienting the material. The enhanced electrical conductivity is isotropic as compared to a stretch oriented film which has isotropic electrical conductivity. In the preferred embodiment, additives …

Go to article

Phase Structures And Morphologies Determined By Competitions Among Self-Organization, Crystallization, And Vitrification In A Disordered Poly(Ethylene Oxide)-B-Polystyrene Diblock Copolymer, Lei Zhu, Yan Chen, Anqui-Q. Zhang, Bret. H. Calhoun, Moonseok Chun, Stephen Z. D. Cheng, Benjamin S. Hsiao, Fengji Yeh, Takeji Hashimoto Oct 1999

Phase Structures And Morphologies Determined By Competitions Among Self-Organization, Crystallization, And Vitrification In A Disordered Poly(Ethylene Oxide)-B-Polystyrene Diblock Copolymer, Lei Zhu, Yan Chen, Anqui-Q. Zhang, Bret. H. Calhoun, Moonseok Chun, Stephen Z. D. Cheng, Benjamin S. Hsiao, Fengji Yeh, Takeji Hashimoto

College of Polymer Science and Polymer Engineering

A poly(ethylene oxide)-b-polystyrene (PEO-b-PS) diblock copolymer having a number-average molecular weight ((M) over bar(n)) of 11000 g/mol in the PEO blocks and an (M) over bar(n) of 5200 g/mol in the PS blocks has been synthesized (with a volume fraction of the PEO blocks of 0.66 in the molten state). Differential scanning calorimetry results show that this copolymer possesses a single endotherm, which is attributed to the melting of the PEG-block crystals. Based on real-time resolved synchrotron small-angle x-ray scattering (SAXS) observations, the diblock copolymer is in a disordered state above the glass transition temperature of the PS-rich phase (T-g(PS)) …

Go to article

Rhythmic Growth Of Target And Spiral Spherulites Of Crystalline Polymer Blends, Thein Kyu, Hw Chiu, Aj Guenthner, Y Okabe, H Saito, T Inoue Oct 1999

Rhythmic Growth Of Target And Spiral Spherulites Of Crystalline Polymer Blends, Thein Kyu, Hw Chiu, Aj Guenthner, Y Okabe, H Saito, T Inoue

College of Polymer Science and Polymer Engineering

Numerical calculations reveal that the target and spiral growth patterns in spherulites can be generated from the time-dependent Ginzburg-Landau equations (model C) by coupling a conserved compositional order parameter and a nonconserved crystal ordering parameter. Of particular interest is that the periodic concentric rings (target) or the spirals at the spherulitic core remain stationary in both the crystal (orientational) ordering field and the concentration field. Another intriguing observation is that the growth of target and spiral spherulites occurs in a stepwise fashion in synchronism with the rhythmic energy dissipation during crystallization.

Go to article

Organic-Metallic Composite Coating For Copper Surface Protection, Ravi F. Saraf Sep 1999

Organic-Metallic Composite Coating For Copper Surface Protection, Ravi F. Saraf

Department of Chemical and Biomolecular Engineering: Patents

Copper-containing surfaces of substrates such as laminated electronic circuit boards are protected by organometallic coatings comprising organic compounds selected from the group consisting of benzimidazoles, alkylimidazoles, benzotriazozles and alkyltriazoles, substituted or unsubstituted, and metal particles of solder-wettable metals or metal solders. The metal particles can be thermally formed in situ from metallic compounds such as noble metal acetates, acetylacetonates and carbonates.

Go to article

Modeling Of Solid Phase Detonations, C Richter, Hendrik J. Viljoen, N.F.J Van Rensburg Sep 1999

Modeling Of Solid Phase Detonations, C Richter, Hendrik J. Viljoen, N.F.J Van Rensburg

Papers in Reaction Kinetics

In contrast to conventional explosives which constitute rapid decomposition of the molecular structure acconlpanied by the release of large volumes of gaseous products, heterogeneous mixtures in the SHS realm react by progression of a thermal wave at velocities far below the speed of sound in such mixtures. Interestingly, ultrafast solid phase reactions can be initiated under the right conditions. A shock wave compresses the solid mixture to densities well beyond the theoretical mean ambient density (TMD) and compression becomes the major form of preheating. In addition, elastic potential energy is pumped into the lattice structure to induce severe distortion and …

Go to article

Network Modeling Of The Convective Flow And Diffusion Of Molecules Adsorbing In Monoliths And In Porous Particles Packed In A Chromatographic Column, J. J. Meyers, Athanasios I. Liapis Aug 1999

Network Modeling Of The Convective Flow And Diffusion Of Molecules Adsorbing In Monoliths And In Porous Particles Packed In A Chromatographic Column, J. J. Meyers, Athanasios I. Liapis

Chemical and Biochemical Engineering Faculty Research & Creative Works

A cubic lattice network of interconnected pores was constructed to represent the porous structure existing in a monolith (continuous bed) or in a column packed with porous chromatographic particles. Expressions were also constructed and utilized to simulate, through the use of the pore network model, the intraparticle interstitial velocity and pore diffusivity of adsorbate molecules in porous chromatographic particles or in monoliths under retained and unretained conditions. The combined effects of steric hindrance at the entrance to the pores and frictional resistance within the pores, as well as the effects of pore size, pore connectivity, n(T), of the porous network, …

Go to article

Polycrystalline Conducting Polymers And Precursors Thereof Having Adjustable Morphology And Physical Properties, Ravi F. Saraf Aug 1999

Polycrystalline Conducting Polymers And Precursors Thereof Having Adjustable Morphology And Physical Properties, Ravi F. Saraf

Department of Chemical and Biomolecular Engineering: Patents

Polycrystalline materials containing crystallies of precursors to electrically conductive polymers and electrically conductive polymers are described which have an adjustable high degree of crystallinity. The intersticial regions between the crystallites contains amorphous material containing precursors to electrically conductive polymers and/or electrically conductive polymers. The degree of crystallinity is achieved by preparing the materials under conditions which provide a high degree of mobility to the polymer molecules permitting them to associate with one another to form a crystalline state. This is preferable achieved by including additives, such as plasticizers and diluents, to the solution from which the polycrystalline material is formed. …

Go to article

Bioactivities Of A Tumour Necrosis Like Factor Released By Chicken Rnacrophages, Silke Rautenschlein, Anuradha Subramanian, Jagdev M. Sharma Jul 1999

Bioactivities Of A Tumour Necrosis Like Factor Released By Chicken Rnacrophages, Silke Rautenschlein, Anuradha Subramanian, Jagdev M. Sharma

Papers in Biotechnology

To test for tumour necrosis-like factor (TNF) of chickens, supernatants of a lipopolysaccharide (LPS)-stimulated chicken macrophage cell line MQ-NCSU were analysed. A sequence of ion-exchange and gel-permeation chromatography was utilised to isolate TNF-like activity from the culture supernatant. The peak of TNF-like cytotoxic activity corresponded to the fractions with a nlolecular weight of 81 kDa or higher. Polyclonal anti-human TNF-a antiserum cross-reacted by Western blotting with a 17 kDa protein in the TNF-containing fraction ~ ~ n d e denaturing conditions. This result indicated that chicken TNF-like factor in the biologically active form may be a protein multimer of monomers …

Go to article

Bioactivities Of A Tumour Necrosis Like Factor Released By Chicken Macrophages, Silke Rautenschlein, Anuradha Subramanian, Jagdev M. Sharma Jul 1999

Bioactivities Of A Tumour Necrosis Like Factor Released By Chicken Macrophages, Silke Rautenschlein, Anuradha Subramanian, Jagdev M. Sharma

Papers in Biotechnology

To test for tumour necrosis-like factor (TNF) of chickens, supernatants of a lipopolysaccharide (LPS)-stimulated chicken macrophage cell line MQ-NCSU were analysed. A sequence of ion-exchange and gel-permeation chromatography was utilised to isolate TNF-like activity from the culture supernatant. The peak of TNF-like cytotoxic activity corresponded to the fractions with a nlolecular weight of 81 kDa or higher. Polyclonal anti-human TNF-a antiserum cross-reacted by Western blotting with a 17 kDa protein in the TNF-containing fraction ~ ~ n d e denaturing conditions. This result indicated that chicken TNF-like factor in the biologically active form may be a protein multimer of monomers …

Go to article

Composite Comprising A Metal Substrate And A Corrosion Protecting Layer, Ravi F. Saraf Jul 1999

Composite Comprising A Metal Substrate And A Corrosion Protecting Layer, Ravi F. Saraf

Department of Chemical and Biomolecular Engineering: Funded Proposals

A composite comprising a metal substrate and as a corrosion protecting layer on at least one major surface of said substrate, a composition comprising a thermoset or thermoplastic polymeric matrix, and a conductive filler component, where said filler component comprises electrically conductive particles.

Go to article

Particle Pressure And Marginal Stability Limits For A Homogeneous Monodisperse Gas-Fluidized Bed: Kinetic Theory And Numerical Simulations, Ashok S. Sangani, Donald L. Koch Jul 1999

Particle Pressure And Marginal Stability Limits For A Homogeneous Monodisperse Gas-Fluidized Bed: Kinetic Theory And Numerical Simulations, Ashok S. Sangani, Donald L. Koch

Biomedical and Chemical Engineering - All Scholarship

A linear stability analysis is performed for the homogeneous state of a monodisperse gas-fluidized bed of spherical particles undergoing hydrodynamic interactions and solid-body collisions at small particle Reynolds number and finite Stokes number. A prerequisite for the stability analysis is the determination of the particle velocity variance which controls the particle-phase pressure. In the absence of an imposed shear, this velocity variance arises solely due to the hydrodynamic interactions among the particles. Since the uniform state of these suspensions is unstable over a wide range of values of particle volume fraction &phgr; and Stokes number St, full dynamic simulations cannot …

Go to article

Fluid Dynamic Parameters In Bubble Columns With Internals, Jinwen Chen, Fan Li, Sujatha Degaleesan, Puneet Gupta, Muthanna H. Al-Dahhan, Milorad P. Duduković, Bernard A. Toseland Jul 1999

Fluid Dynamic Parameters In Bubble Columns With Internals, Jinwen Chen, Fan Li, Sujatha Degaleesan, Puneet Gupta, Muthanna H. Al-Dahhan, Milorad P. Duduković, Bernard A. Toseland

Chemical and Biochemical Engineering Faculty Research & Creative Works

The Knowledge of Gas Holdup, Liquid Recirculation and Turbulent Parameters is Important for Design and Performance Calculation of Bubble Column Reactors. Although Numerous Experimental Studies Have Been Reported on This Subject, Most Are Point Measurements Limited to Columns Without Internals Operated at Low Gas Velocities. in This Study, We Present the Results Obtained for the Gas Holdup Profiles, Time-Averaged Liquid Velocity Profiles, Turbulent Stresses and Eddy Diffusivities (Radial and Axial) Obtained in a 18″ (44 Cm) Diameter Column Without and with Internals Similar to Those Used in Industrial Scale Units (E.g., Heat Exchanger Tubes) using Both Air/water and Air/drakeoil 10 …

Go to article

Two-Phase Flow Distribution In 2d Trickle-Bed Reactors, Y. Jiang, M. R. Khadilkar, M. (Muthanna) H. Al-Dahhan, M. P. Dudukovic Jul 1999

Two-Phase Flow Distribution In 2d Trickle-Bed Reactors, Y. Jiang, M. R. Khadilkar, M. (Muthanna) H. Al-Dahhan, M. P. Dudukovic

Chemical and Biochemical Engineering Faculty Research & Creative Works

An Extended Discrete Cell Model (DCM), based on Minimization of Energy Dissipation Rate, is Applied to Predict Two-Phase Flow Distribution in the Two-Dimensional Trickle-Bed Reactors. the Main Advantages of DCM Are that It Can Qualitatively Capture the Experimental Observations, and Readily Distinguish between Flow Distribution in Prewetted and Non-Prewetted Beds, as Well as Reflect the Effects of Bed Structure and Inlet Liquid Distributor on Two Phase Flow Distribution. for Comparison Purpose, the Results of Liquid Distribution Obtained by DCM Are Compared with Both Computational Fluid Dynamics (CFD) Simulations and Experimental Observations in a 2D Bed. the Achieved Qualitative and Quantitative …

Go to article

Comparative Hydrodynamics Study In A Bubble Column Using Computer-Automated Radioactive Particle Tracking (Carpt)/Computed Tomography (Ct) And Particle Image Velocimetry (Piv), Jinwen Chen, Abdenour Kemoun, Muthanna H. Al-Dahhan, Milorad P. Duduković, D. J. Lee, Liang Shih Fan Jul 1999

Comparative Hydrodynamics Study In A Bubble Column Using Computer-Automated Radioactive Particle Tracking (Carpt)/Computed Tomography (Ct) And Particle Image Velocimetry (Piv), Jinwen Chen, Abdenour Kemoun, Muthanna H. Al-Dahhan, Milorad P. Duduković, D. J. Lee, Liang Shih Fan

Chemical and Biochemical Engineering Faculty Research & Creative Works

The Hydrodynamics of a 10-Cm-Diameter Cylindrical Bubble Column at the Superficial Gas Velocity of 2, 4, and 8 Cm/s Are Investigated by Computer-Automated Radioactive Particle Tracking (CARPT), Particle Image Velocimetry (PIV), and Computed Tomography (CT). These Experimental Techniques Are Capable of Providing the Knowledge of Velocity and Holdup Fields in a Bubble Column System, Which Are Essential as the Experimental Benchmark for Modeling of Such Systems. the Flow Field of Liquid Phase, as Well as the Reynolds Stresses, Obtained by CARPT and PIV in an Air-Water System Are Compared in Detail. the Results Indicate that CARPT and PIV Complement Each …

Go to article

Parametric Study Of Unsteady-State Flow Modulation In Trickle-Bed Reactors, M. R. Khadilkar, M. (Muthanna) H. Al-Dahhan, M. P. Duduković Jul 1999

Parametric Study Of Unsteady-State Flow Modulation In Trickle-Bed Reactors, M. R. Khadilkar, M. (Muthanna) H. Al-Dahhan, M. P. Duduković

Chemical and Biochemical Engineering Faculty Research & Creative Works

Unsteady-State Liquid Flow Modulation (Periodic Operation) Was Investigated for Hydrogenation of Alpha-Methylstyrene to Cumene in a Hexane Solvent over 0.5% Pd on Alumina Spheres. This Test Reaction Was Run under Both Gas and Liquid Reactant-Limited Conditions. It is Shown that Periodic Liquid Flow Modulation Can Alter the Supply of Liquid and Gaseous Reactants to the Catalyst and Result in Reactor Performance Different from that Obtained under Steady-State Conditions. the Effect of Key Parameters Such as Extent of Gas/liquid Limitation, Total Cycle Period, Cycle Split, and Liquid Mass Velocity Were Investigated Experimentally to Demonstrate the Cause-Effect Relationships in Periodic Operation. Performance …

Go to article

Method For Providing Discharge Protection Or Shielding, Ravi F. Saraf Jun 1999

Method For Providing Discharge Protection Or Shielding, Ravi F. Saraf

Department of Chemical and Biomolecular Engineering: Funded Proposals

Electrostatic discharge protection and electromagnetic interference shielding is provided by applying to a dielectric substrate a composition comprising a polymeric matrix and a conductive filler component. The conductive filler component comprises electrically conductive metal particles and at least one electrically conducting polymer.

Go to article

Development Of A Curved Layer Lom Process For Monolithic Ceramics And Ceramic Matrix Composites, Donald A. Klosterman, Richard P. Chartoff, Nora R. Osborne, George A. Graves, Allan Lightman, Gyoowan Han, Akos Bezewredi, Stan Rodrigues, Sung Pak, Gary Kalmanovich, Leon Dodin, Song Tu Jun 1999

Development Of A Curved Layer Lom Process For Monolithic Ceramics And Ceramic Matrix Composites, Donald A. Klosterman, Richard P. Chartoff, Nora R. Osborne, George A. Graves, Allan Lightman, Gyoowan Han, Akos Bezewredi, Stan Rodrigues, Sung Pak, Gary Kalmanovich, Leon Dodin, Song Tu

Chemical and Materials Engineering Faculty Publications

A novel rapid prototyping technology incorporating a curved layer building style was developed. The new process, based on Laminated Object Manufacturing (LOM), was designed for efficient fabrication of curved layer structures made from ceramics and fiber reinforced composites. A new LOM machine was created, referred to as Curved Layer LOM. This new machine uses ceramic tapes and fiber prepregs as feedstocks and fabricates curved structures on a curved-layer by curved-layer basis. The output of the process is a three dimensional "green" ceramic that is capable of being processed to a seamless, fully dense ceramic using traditional techniques. A detailed description …

Go to article

Biodegradation Of Thermoplastic And Hermosetting Polyesters From Z-Protected Glutamic Acid, R M. Tadros, Hossein Noureddini, Delmar C. Timm Jun 1999

Biodegradation Of Thermoplastic And Hermosetting Polyesters From Z-Protected Glutamic Acid, R M. Tadros, Hossein Noureddini, Delmar C. Timm

Papers in Biomolecular Engineering

In a previous article,1 the development and molecular characterization of three polyesters from N-carbobenzyloxy-L-glutamic acid (ZGluOH) were reported. The polymers were a linear, heterochain polyester (ZGluOH and ethylene glycol), a crosslinked heterochain polyester (ZGluOH and diglycidyl ether of 1,4-butanediol), and a crosslinked, heterochain aromatic polyester (ZGluOH and diglycidyl ether of bisphenol A). In this manuscript, results of biodegradation studies are reported. The three polymers hydrolyzed to low molecular weight oligomers similar to the monomers with lipase. When exposed to a mixed culture of micro-organisms, the first two resins degraded to biomass and respiratory gases. The crosslinked heterochain aromatic polyester resisted …

Go to article

Method Of Coupling Ligands Onto Supports And Products Produced Therefrom , William H. Velander May 1999

Method Of Coupling Ligands Onto Supports And Products Produced Therefrom , William H. Velander

Department of Chemical and Biomolecular Engineering: Patents

A method is disclosed for coupling a ligand within a porous support. The method involves mixing ligand and porous support under conditions sufficient to suppress coupling conditions of the ligand to the porous support while enhancing the relative rate of diffusion, to the rate of reaction, of the ligand into and within the porous support, and then altering the conditions to enhance rapid coupling of the ligand within the porous support. The alteration from diffusion conditions to coupling conditions involves a change in the reaction solution of pH, ionic strength, temperature, coupling competitor, such that a relatively lower Thiele Modulus …

Go to article

Method Of Coupling Ligands Onto Supports And Products Produced Therefrom , William H. Velander, Anuradha Subramanian May 1999

Method Of Coupling Ligands Onto Supports And Products Produced Therefrom , William H. Velander, Anuradha Subramanian

Department of Chemical and Biomolecular Engineering: Patents

A method is disclosed for coupling a ligand within a porous support. The method involves mixing ligand and porous support under conditions sufficient to suppress coupling conditions of the ligand to the porous support while enhancing the relative rate of diffusion, to the rate of reaction, of the ligand into and within the porous support, and then altering the conditions to enhance rapid coupling of the ligand within the porous support. The alteration from diffusion conditions to coupling conditions involves a change in the reaction solution of pH, ionic strength, temperature, coupling competitor, such that a relatively lower Thiele Modulus …

Go to article

Reversal Flow In Fixed-Bed Reactors Operating Under Reaction-Regeneration Cycles, Daniel O. Borio, Noemi S. Schbib, Jorge E. Gatica May 1999

Reversal Flow In Fixed-Bed Reactors Operating Under Reaction-Regeneration Cycles, Daniel O. Borio, Noemi S. Schbib, Jorge E. Gatica

Chemical & Biomedical Engineering Faculty Publications

The unsteady state simulation of a set of industrial fixed-bed reactors is presented. The catalytic dehydrogenation of 1-butene into 1-3-butadiene is selected as case study. These reactors operate under reaction-regeneration cycles. Each stage of the process, i.e., dehydrogenation (deactivation by coking), steam purge, oxidative regeneration and evacuation, is simulated by means of the corresponding dynamic model. The kinetic parameters used in the dehydrogenation and regeneration stages for a Cr2O3/Al2O3 catalyst are taken from the literature. The performance of the reactors is investigated for two different operation modes: conventional …

Go to article

Ultrasonic Enhancement Of Antibiotic Action On Escherichia Coli Biofilms: An In Vivo Model, Andrea M. Rediske, Beverly L. Roeder, Maren K. Brown, Jared L. Nelson, Rachel L. Robison, David O. Draper, G. Bruce Schaalje, Richard A. Robison, William G. Pitt May 1999

Ultrasonic Enhancement Of Antibiotic Action On Escherichia Coli Biofilms: An In Vivo Model, Andrea M. Rediske, Beverly L. Roeder, Maren K. Brown, Jared L. Nelson, Rachel L. Robison, David O. Draper, G. Bruce Schaalje, Richard A. Robison, William G. Pitt

Faculty Publications

Biofilm infections are a common complication of prosthetic devices in humans. Previous in vitro research has determined that low-frequency ultrasound combined with aminoglycoside antibiotics is an effective method of killing biofilms. We report the development of an in vivo model to determine if ultrasound enhances antibiotic action. Two 24-h-old Escherichia coli (ATCC 10798) biofilms grown on polyethylene disks were implanted subcutaneously on the backs of New Zealand White female rabbits, one on each side of the spine. Low-frequency (28.48-kHz) and low-power-density (100- and 300-mW/cm2) continuous ultrasound treatment was applied for 24 h with and without systemic administration of gentamicin. The …

Go to article

Next Last