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Full-Text Articles in Chemical Engineering

Solitary Waves And Supersonic Reaction Front In Metastable Solids, Hendrik J. Viljoen, Lee L. Lauderback, D. Sornette Dec 2000

Solitary Waves And Supersonic Reaction Front In Metastable Solids, Hendrik J. Viljoen, Lee L. Lauderback, D. Sornette

Hendrik J. Viljoen Publications

Motivated by an increasing number of remarkable experimental observations on the role of pressure and shear stress in solid reactions, explosions and detonations, we present a simple toy model that embodies nonlinear elasticity and dispersion as well as chemical or phase transformation. This generalization of the Toda Lattice provides an effective model for the description of the organization during an abrupt transformation in a solid. One of the challenges is to capture both the equilibrium degrees of freedom as well as to quantify the possible role of out-of-equilibrium perturbations. In the Toda Lattice, we verify that the particle velocities converge …


Electrically Conductive Polymeric Materials And Use Thereof, Ravi F. Saraf Nov 2000

Electrically Conductive Polymeric Materials And Use Thereof, Ravi F. Saraf

Department of Chemical and Biomolecular Engineering: Patents

A polymer blend composition, capable of being made electrically conductive by application of heat having an electrically conductive upon doping polymer in undoped form; the undoped polymer is selected from the group consisting of substituted and unsubstituted polyparaphenylenevinylenes, polyanilines, polyazines, polythiophenes, poly-p-phenylene sulfides, polyfuranes, polyselenophenes, polyacetylenes filtered from soluble precursors and combinations and blends thereof, compounded and blended at a molecular scale with a dielectric polymer; wherein the dielectric polymer is selected from the group consisting of interpolymers of acrylonitrile-butadiene-styrene, acetal acrylic liquid crystal polymers, polybutylene terephthalate, polycarbonate, polyester, polyetherimide, polyethersulfone, polyethylene, polyethylene terephthalate, polyphenylene oxide, polyphenylene sulfide, polypropylene, polystyrene, …


Electrically Conductive Polymeric Materials And Use Thereof, Ravi F. Saraf Nov 2000

Electrically Conductive Polymeric Materials And Use Thereof, Ravi F. Saraf

Department of Chemical and Biomolecular Engineering: Patents

A polymer blend composition, capable of being made electrically conductive by application of heat having an electrically conductive upon doping polymer in undoped form; the undoped polymer is selected from the group consisting of substituted and unsubstituted polyparaphenylenevinylenes, polyanilines, polyazines, polythiophenes, poly-p-phenylene sulfides, polyfuranes, polyselenophenes, polyacetylenes filtered from soluble precursors and combinations and blends thereof, compounded and blended at a molecular scale with a dielectric polymer; wherein the dielectric polymer is selected from the group consisting of interpolymers of acrylonitrile-butadiene-styrene, acetal acrylic liquid crystal polymers, polybutylene terephthalate, polycarbonate, polyester, polyetherimide, polyethersulfone, polyethylene, polyethylene terephthalate, polyphenylene oxide, polyphenylene sulfide, polypropylene, polystyrene, …


Lead-Free Interconnection For Electronic Devices, Ravi F. Saraf Oct 2000

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 …


Modeling Pichia Pastoris Growth On Methanol And Optimizing The Production Of A Recombinant Protein, The Heavy-Chain Fragment C Of Botulinum Neurotoxin, Serotype A, Wenhui Zhang, Mark A. Bevins, Bradley A. Plantz, Leonard A. Smith, Michael M. Meagher Oct 2000

Modeling Pichia Pastoris Growth On Methanol And Optimizing The Production Of A Recombinant Protein, The Heavy-Chain Fragment C Of Botulinum Neurotoxin, Serotype A, Wenhui Zhang, Mark A. Bevins, Bradley A. Plantz, Leonard A. Smith, Michael M. Meagher

Papers in Biotechnology

An unstructured growth model for the recombinant methylotrophic yeast P. pastoris Mut+ expressing the heavy-chain fragment C of botulinum neurotoxin serotype A [BoNT/A(Hc)], was successfully established in quasi-steady state fed-batch fermentations with varying cell densities. The model describes the relationships between specific growth rate and methanol concentration, and the relationships between specific methanol and ammonium consump-tion rates and specific growth rate under methanol-limited growth conditions. The maximum specific growth rate (μ) determined from the model was 0.08 h−1 at a methanol concentration of 3.65 g/L, while the actual maximum μ was 0.0709 h−1. The maximum specific methanol consumption rate was …


Fermentation Strategies For Recombinant Protein Expression In The Methylotrophic Yeast Pichia Pastoris, Wenhui Zhang, Mehmet Inan, Michael M. Meagher Aug 2000

Fermentation Strategies For Recombinant Protein Expression In The Methylotrophic Yeast Pichia Pastoris, Wenhui Zhang, Mehmet Inan, Michael M. Meagher

Papers in Biochemical Engineering

Fermentation strategies for recombinant protein production in Pichia pastoris have been investigated and are reviewed here. Characteristics of the expression system, such as phenotypes and carbon utilization, are summarized. Recently reported results such as growth model establishment, application of a methanol sensor, optimization of substrate feeding strategy, DOstat controller design, mixed feed technology, and perfusion and continuous culture are discussed in detail.


Enhanced Adhesion Between A Vapor Deposited Metal And An Organic Polymer Surface Exhibiting Tailored Morphology, Ravi F. Saraf Aug 2000

Enhanced Adhesion Between A Vapor Deposited Metal And An Organic Polymer Surface Exhibiting Tailored Morphology, Ravi F. Saraf

Department of Chemical and Biomolecular Engineering: Patents

Enhanced adhesion between a vapor deposited metal and an organic polymer surface is achieved without utilizing any intermediate surface preparatory steps. The morphology of the polymer surface is tailored to produce mounds and dimples on the surface which leads to a mechanically tougher, interdigitated metal/polymer interface. In the preferred embodiment, a solution of a solvent or solvent system and two or more polymer precursors or polymers or combinations thereof are cast in a film on a substrate and heated to spontaneously form a rough surface due to phase separation. The surface topography of such a film consists of characteristic mounds …


Micro Goniometer For Scanning Microscopy, Ravi F. Saraf Aug 2000

Micro Goniometer For Scanning Microscopy, Ravi F. Saraf

Department of Chemical and Biomolecular Engineering: Patents

A goniometer for performing scanning probe microscopy on a substrate surface is disclosed. The goniometer has a cantilever, having a cantilevered end and a supported end and a tip disposed at the cantilevered end of the cantilever. The goniometer also has a block disposed at the supported end of the cantilever. The block has at least one pair of piezoelectric layers, a pair of electrodes disposed about each individual piezoelectric layer such that varying a potential difference applied between the individual electrodes of a pair of electrodes causes the corresponding piezoelectric layer to deform, and a first insulating material disposed …


Facile Sol-Gel Synthesis Of Porous Silicas Using Poly(Propylene)Imine Dendrimers As Templates, Gustavo F. Larsen, Edgar Lotero, Manuel Marquez Aug 2000

Facile Sol-Gel Synthesis Of Porous Silicas Using Poly(Propylene)Imine Dendrimers As Templates, Gustavo F. Larsen, Edgar Lotero, Manuel Marquez

Gustavo Larsen Publications

Commercially available poly(propylene)imine (DAB-Am-32 and DAB-Am-64) dendrimers were used as single-molecule templates to tailor the porosity of silicas via a nonacidic sol-gel method. X-ray diffraction on both the as-prepared (oven-dried at 373 K) and the calcined (833 K) materials revealed that modest contraction took place on template removal and that the cavities created did not achieve three-dimensional ordering under the current synthesis conditions. Transmission electron microscopy of “Pt-stained” samples supported this picture. A modified Horvath–Kawazoe analysis of the argon adsorption isotherms indicated that DAB-Am-64 is a much more effective template than DAB-Am-32. Pyrolysis and oxidation protocols for template removal are …


Piezoelectric Sensors / Actuators For Use In Refractory Environments, Hendrik J. Viljoen, Barend R. Jooste May 2000

Piezoelectric Sensors / Actuators For Use In Refractory Environments, Hendrik J. Viljoen, Barend R. Jooste

Papers in Reaction Kinetics

pierozlectric properties over a large temperature range of from room temperature to approximately 1360 degrees centigrade. The piezarlecttic system is sequentially comprised of a first electrically conductive layer, a layer of (Ta,O,) in other than a rnonoclinic phase, ipreferably onhorhombic demonstrating small x-ray crystalopraphic and peaksi. and a second slecttically conductive layer A preferred method of fabrication involves sputter deposition of both said layer of (Ta,O) md said second electrically conductive layer.


Immunoaffinity Chomatography, Anuradha Subramanian Apr 2000

Immunoaffinity Chomatography, Anuradha Subramanian

Papers in Biotechnology

Recent devclopments in recombinant DNA technology have enabled the synthesis of valuable therapeutic proteins in bacterial cells as well as in novel eucaryotic expression systems. However, the purification of proteins of interest from either the conventional sources, cell culture, or novel routes in a highly purified form necessitates the development of separation tcchniques capable of recovering proteins from these feed streams in a highly purified form (1,2). Purification of therapeutic proteins from biological sources is usually complicated by the presence of endogenous proteins (2). Purification methodologies based on ion exchange or adsorption serve as excellent prepurification steps, but they fail …


Ultra High Density Storage Media And Method Thereof, Ravi F. Saraf Jan 2000

Ultra High Density Storage Media And Method Thereof, Ravi F. Saraf

Department of Chemical and Biomolecular Engineering: Patents

A storage media for storing information having a substrate. The substrate has an upper surface and a molecular weight greater than 5,000. Preferably the material is a polymer. The material has a plurality of piles of molecular chains in selected areas formed by pushing the molecular chains of the material on its upper surface to the selected area mechanically with a mechanical tool. The piles represent written information. The mechanical tool is preferably an atomic force microscope. Another aspect of the present invention is a method for storing information having the steps of selecting a material substrate having an upper …


Composition Containing A Polymer And Conductive Filler And Use Thereof, Ravi F. Saraf Jan 2000

Composition Containing A Polymer And Conductive Filler And Use Thereof, Ravi F. Saraf

Department of Chemical and Biomolecular Engineering: Patents

A composition containing a polymeric matrix and a conductive filler component is provided. The conductive filler component comprises conductive particles and a polymer selected from the group consisting of substituted and unsubstituted polyanilines, substituted and unsubstituted polyparaphenylenevinylenes, substituted and unsubstituted polythiophenes, substituted and unsubstituted polyazines, substituted and unsubstituted polyparaphenylenes, substituted and unsubstituted polyfuranes, substituted and unsubstituted polypyrroles, substituted and unsubstituted polyselenophene, substituted and unsubstituted poly-p-phenylene sulfides and substituted and unsubstituted polyacetylenes, and mixtures thereof, and copolymers thereof. Compositions of the present invention are useful as corrosion protecting layers for metal substrates, for electrostatic discharge protection, electromagnetic interference shielding, and as …


Purification Of Immunoglobulins From Serum Using Thiophilic Cellulose Beads, Anuradha Subramanian Jan 2000

Purification Of Immunoglobulins From Serum Using Thiophilic Cellulose Beads, Anuradha Subramanian

Papers in Biotechnology

This study evaluates the chromatographic performance of a support obtained by the reaction of mercaptoethanol with cellulose beads activated with divinyl sulfone. Cellulose beads 500-800 microns (pm) in diameter and with a solids content of 3.5% were selected for this study. A two-step sequence of permeation and reaction was used to install thiophilic sites throughout the cross section of the bead. The distribution of thiophilic sites was visualized by immobilizing fluorescent antibodies. Human and porcine serum proteins were separated on the thiophilic support at different linear velocities. Thiophilic cellulose beads were observed to bind human and porcine immunoglobulins (IgG) selectively …


Process For Producing Biodiesel Fuel With Reduced Viscosity And A Cloud Point Below Thirty-Two (32) Degrees Fahrenheit, Hossein Noureddini Jan 2000

Process For Producing Biodiesel Fuel With Reduced Viscosity And A Cloud Point Below Thirty-Two (32) Degrees Fahrenheit, Hossein Noureddini

Department of Chemical and Biomolecular Engineering: Patents

Triglycerides are reacted in a liquid phase reaction with methanol and a homogeneous basic catalyst. The reaction yields a spatially separated two phase result with an upper located non-polar phase consisting principally of non-polar methyl esters and a lower located phase consisting principally of glycerol and residual methyl esters. The glycerol phase is passed through a strong cationic ion exchanger to remove anions, resulting in a neutral product which is flashed to remove methanol and which is reacted with isobutylene in the presence of a strong acid catalyst to produce glycerol ethers. The glycerol ethers are then added back to …


Electrode Modification Using An Unzippable Polymer Paste, Ravi F. Saraf Jan 2000

Electrode Modification Using An Unzippable Polymer Paste, Ravi F. Saraf

Department of Chemical and Biomolecular Engineering: Patents

A paste is described for capping electrodes with an oxide free metal layer incorporating a solvent, an unzippable polymer and particles. The electrode could be an interconnect such as a C4 bump. A method for forming a coating and for testing integrated circuit chips is also described. The invention overcomes the problem of interconnecting Pb containing electrodes that are covered with an insulating oxide on integrated circuit chips by coating the Pb containing electrode with Au to provide an oxide free surface for testing and interconnection.


Production And Purification Of The Heavy Chain Fragment C Of Botulinum Neurotoxin, Serotype A, Expressed In The Methylotrophic Yeast Pichia Pastoris, Karen J. Potter, Wenhui Zhang, Leonard A. Smith, Michael M. Meagher Jan 2000

Production And Purification Of The Heavy Chain Fragment C Of Botulinum Neurotoxin, Serotype A, Expressed In The Methylotrophic Yeast Pichia Pastoris, Karen J. Potter, Wenhui Zhang, Leonard A. Smith, Michael M. Meagher

Michael Meagher Publications

A recombinant Hc fragment of botulinum neurotoxin, serotype A (rBoNTA(Hc)), has been successfully expressed in a Mutt strain of the methylotrophic yeast Pichia pastoris for use as an antigen in a proposed human vaccine. Fermentation employed glycerol batch, glycerol-fed batch, and methanol-fed batch phases to achieve high cell density. Induction times were short to maximize rBoNTA(Hc) production while minimizing proteolytic degradation. Concentration of rBoNTA(Hc) in yeast cell lysates was generally 1-2% of the total protein based on ELISA analysis. The Hc fragment was purified from cell lysates using a multistep ion-exchange (IEC) chromatographic process, including …


Ranking The Factors Impacting Lmmunosorbent Performance, Anuradha Subramanian, William H. Velander Jan 2000

Ranking The Factors Impacting Lmmunosorbent Performance, Anuradha Subramanian, William H. Velander

Papers in Biotechnology

This work addresses the relative impact of the phenomena of orientation, multipoint attachment, and local density of the immobilized antibody 011 immunosorbent perfornnance. The masking of the antigen binding domains of monoclonal antibodies (Mab) by Fab Masking Antigens (FMAs) was used as a tool to determine the impact of orientation on the perforn~anceo f Emphaze, Affiprep'M, and Cellulose bead-based immunosorbents. A two-step antibody immobilization inethod involving permeation of the beaded matrix followed by a fast coupling reaction was used to study the effect of local density of the Mnh on immunosorbent efficiency. Lysyl groups on Mabs were covalently modified to …