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2005

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Articles 181 - 188 of 188

Full-Text Articles in Chemical Engineering

Wetting Kinetics Of Films Containing Non-Adsorbing Polymers, S. Saritha, Xianzhong Zhang, Partho Neogi Jan 2005

Wetting Kinetics Of Films Containing Non-Adsorbing Polymers, S. Saritha, Xianzhong Zhang, Partho Neogi

Chemical and Biochemical Engineering Faculty Research & Creative Works

Kinetics of wetting by a polymer solution have been studied theoretically for a film pinned to a slot. The fluid mechanical equations have been solved using a numerical scheme. The role of polymers appears in the disjoining pressure in the model. The spreading kinetics are observed to follow a power law: a power of (1/4) is observed at short times due to the Laplace pressure, and (1/2) at large times under the Hamaker part of the disjoining pressure at very large times and with no equilibration. It is argued and demonstrated that techniques which have low resolutions such as microscopy …

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Design, Fabrication And Performance Evaluation Of An Impedimetric Urea Biosensor System, Vandana Gupta Jan 2005

Design, Fabrication And Performance Evaluation Of An Impedimetric Urea Biosensor System, Vandana Gupta

Theses and Dissertations

An impedance bioanalyzer system comprising an in-vitro biotransducer, instrumentation and control software for the measurement of urea, potentially in blood dialysate, has been developed. The biotransducer comprises of a microlithographically fabricated interdigitated microsensor electrode (IME) onto which was cast a biorecognition layer conferred with the specificity of the enzyme urease. Urease hydrolysis of urea produces NH4+, HC03- and OH- ions that decrease the device's impedance. The temporal rate of change (kinetic) and the extent of change (equilibrium) of ion concentration were measured as the sensor's response. Five formats: [i) unPEGylated urease-containing poly(hydroxyethylmethacrylate) [p(HEMA)] hydrogel, ii) PEGylated urease-containing p(HEMA) hydrogel, iii) …

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Synthesis And Characterization Of Methylene Bis (P-Cyclohexyl Isocyanate)-Poly (Tetramethyl Oxide) Based Polyurethane Elastomers, Kennard Marcellus Brunson Jan 2005

Synthesis And Characterization Of Methylene Bis (P-Cyclohexyl Isocyanate)-Poly (Tetramethyl Oxide) Based Polyurethane Elastomers, Kennard Marcellus Brunson

Theses and Dissertations

This research concerns the development and characterization of methylene bis (p-cyclohexyl isocyanate/butanediol) (HMDI/BD) based polyurethanes used in connection with surface-active anti-microbial polyurethanes. Previously studied polyurethanes having an isophorone diisocyanate/butanediol (IPDI/BD) hard block contaminated water during dynamic contact angle (DCA) analyses. This contamination by unknown species confounds results from biocidal studies and jeopardizes the use of the polyurethane as a matrix polyurethane. By contrast, polyurethanes with methylene bis (p-cyclohexyl isocyanate)/butanediol hard block showed no contamination during DCA analysis. For this reason, further study of HMDI/BD/PTMO polyurethanes was conducted. HMDI/BD polyurethanes were synthesized with 15-50wt% hard block and a soft block of …

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Polymerization Kinetics Of Peo-B-Pnipaam Block Copolymers, William G. Pitt, Yi Zeng Jan 2005

Polymerization Kinetics Of Peo-B-Pnipaam Block Copolymers, William G. Pitt, Yi Zeng

Faculty Publications

Our research in ultrasonic activated drug delivery motivated us to develop polymeric micelles that sequester hydrophobic drugs (Fig. 1) until they are sheared open by cavitation events produced by low frequency ultrasound (Fig. 2). [1] Using this type of drug delivery system, micelles sequestering drug can circulate freely without releasing their drug until they flow through a tumor or other tissue insonated by low frequency ultrasound. There they release part of their drug (Fig. 3). [2,3] This drug delivery technology was used to reduce tumors in a rat model [4] using block copolymers of PEO and PPO. However, we are …

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Mechanism Of Targeted Chemotherapeutic Delivery Using Ultrasound, Thaidra A. Gaufin, Byron K. Murray, Seiga Ohmine, Kim L. O'Neill, William G. Pitt, Briant S. Stringham Jan 2005

Mechanism Of Targeted Chemotherapeutic Delivery Using Ultrasound, Thaidra A. Gaufin, Byron K. Murray, Seiga Ohmine, Kim L. O'Neill, William G. Pitt, Briant S. Stringham

Faculty Publications

Ultrasound (US) is used to enhance and target delivery of drugs and genes to cancer tissues. The advantages of focused delivery to select tissues are manifold, but the exact mechanisms are largely unknown and need clarification to optimize delivery. The present study further defined the role of collapse cavitation in US-induced permeabilization of cell membranes and subsequent drug or gene uptake by the cell. Cavitation, defined as the collapse of micro-bubbles, produces high shear stresses and shock waves that may transiently puncture cell membranes and has been suggested as the cause of increased permeability. The hypothesis that collapsing bubbles permeabilize …

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Effects Of Pressure On Coal Pyrolysis And Char Morphology, Dong Zeng, Thomas H. Fletcher Jan 2005

Effects Of Pressure On Coal Pyrolysis And Char Morphology, Dong Zeng, Thomas H. Fletcher

Faculty Publications

A better understanding of high-pressure coal pyrolysis is needed to design advanced coal gasification combined-cycle systems. High-temperature, high-heating-rate, and high-pressure pyrolysis experiments were conducted on three bituminous coals and a lignite, to more fully understand the effects of pressure on resultant char properties. A flat-flame burner was designed and used inside a high-pressure drop-tube reactor to provide a high-temperature, high-heatingrate environment that is representative of industrial processes. Chars were prepared at four different pressures, ranging from 0.85 atm to 15 atm. The measured total volatiles yields compared well with predictions of the Chemical Percolation Devolatilization (CPD) model. The physical properties …

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Simulated Land-Based Turbine Deposits Generated In An Accelerated Deposition Facility, Jared W. Jensen, Sean W. Squire, Jeffrey P. Bons, Thomas H. Fletcher Jan 2005

Simulated Land-Based Turbine Deposits Generated In An Accelerated Deposition Facility, Jared W. Jensen, Sean W. Squire, Jeffrey P. Bons, Thomas H. Fletcher

Faculty Publications

This report presents a validation of the design and operation of an accelerated testing facility for the study of foreign deposit layers typical to the operation of land-based gas turbines. This facility was designed to produce turbine deposits in a 4-h test that would simulate 10,000 h of turbine operation. This is accomplished by matching the net foreign particulate throughput of an actual gas turbine. Flow Mach number, temperature and particulate impingement angle are also matched. Validation tests were conducted to model the ingestion of foreign particulate typically found in the urban environment. The majority of this particulate is ceramic …

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Observations Of Flame Behavior In A Laboratory-Scale Premixed Natural Gas/Air Gas Turbine Combustor From Planar Laser Induced Fluorescence Measurements Of Oh, Laser Doppler Anemometer Velocity Measurements, And Coherent Anti-Stokes Roman Spectrometer Temperature Measurements, Thomas H. Fletcher Jan 2005

Observations Of Flame Behavior In A Laboratory-Scale Premixed Natural Gas/Air Gas Turbine Combustor From Planar Laser Induced Fluorescence Measurements Of Oh, Laser Doppler Anemometer Velocity Measurements, And Coherent Anti-Stokes Roman Spectrometer Temperature Measurements, Thomas H. Fletcher

Faculty Publications

Instantaneous planar laser induced fluorescence (PLIF) images of OH, simultaneous axial/radial and axial/tangential velocity measurements with an LDA (laser Doppler anemometer), and instantaneous gas temperature measurements using a coherent anti- Stokes Raman spectrometer (CARS) were obtained in a pre-mixed, swirl-stabilized laboratory-scale combustor, fired with natural gas. Four operating conditions were examined (two swirl conditions and equivalence ratios of 0.80 and 0.65). The instantaneous PLIF images of OH illustrate the chaotic nature of the turbulent flame eddies. Mean and standard deviations of each variable were measured at different locations in the flame, along with probability density functions. Stability of the flame …

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