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Articles 1 - 8 of 8

Full-Text Articles in Engineering

Flux Analysis In Central Carbon Metabolism In Plants: 13c Nmr Experiments And Analysis , Ganesh Sriram Jan 2004

Flux Analysis In Central Carbon Metabolism In Plants: 13c Nmr Experiments And Analysis , Ganesh Sriram

Retrospective Theses and Dissertations

Metabolic flux analysis is crucial in metabolic engineering. This research concentrated on improvements in 13C labeling-based flux analysis, a powerful flux quantification method, particularly oriented toward application to plants. Furthermore, systemic 13C flux analyses were performed on two model plant systems: Glycine max (soybean) embryos, and Catharanthus roseus hairy roots.;The concepts 'bond integrity', 'bondomer' and the algorithm 'Boolean function mapping' were introduced, to facilitate efficient flux evaluation from carbon bond labeling experiments, and easier flux identifiability analysis.;13C labeling experiments were performed on developing soybean (Glycine max) embryos and C. roseus hairy roots. A computer program, NMR2Flux, was developed ...


Engineering Bioerodible Polymers With Tailored Micro/Nanostructure For Vaccine Delivery , Matthew J. Kipper Jan 2004

Engineering Bioerodible Polymers With Tailored Micro/Nanostructure For Vaccine Delivery , Matthew J. Kipper

Retrospective Theses and Dissertations

This work describes the investigation of bioerodible polyanhydrides as controlled drug delivery vehicles. The polymers studied are based on the 1,6-bis(p-carboxyphenoxy)hexane (CPH) and sebacic acid (SA) monomers. These two materials erode at vastly different rates and can be combined in random copolymers or blends to achieve tailored erosion kinetics. The hydrophobic nature of these materials offers the potential to stabilize proteins, and their mutual incompatibility and semicrystallinity provide an interesting phase behavior, which can be exploited to aid in tailoring the release kinetics. Theoretical and experimental description of the microstructure of polyanhydride copolymers reveals the details of ...


Combinatorial Synthesis And Screening Of Fuel Cell Catalysts , Shrisudersan Jayaraman Jan 2004

Combinatorial Synthesis And Screening Of Fuel Cell Catalysts , Shrisudersan Jayaraman

Retrospective Theses and Dissertations

Polymer electrolyte membrane fuel cells (PEMFCs) are compact power sources that can operate with high efficiencies and low emission of environmentally harmful gases. One of the major barriers impeding the development of PEMFCs as a competitive energy source is the inability of existing anode catalysts to oxidize fuels other than hydrogen at sufficient levels due to catalyst deactivation by carbon monoxide (CO) and other partial oxidation products. The focus of this research is the development and application of combinatorial strategies to construct and interrogate electrooxidation (anode) catalysts pertaining to PEMFCs to discover catalysts with enhanced performance in catalyst deactivating environments ...


The Role Of Reduction In The Deactivation Of Potassium-Promoted Iron Oxide Dehydrogenation Catalysts , Sipho C. Ndlela Jan 2004

The Role Of Reduction In The Deactivation Of Potassium-Promoted Iron Oxide Dehydrogenation Catalysts , Sipho C. Ndlela

Retrospective Theses and Dissertations

One of the largest commercial application for potassium promoted iron oxide catalyst (K-Fe2O3) in petrochemical industry is in the dehydrogenation of ethylbenzene (EB) to styrene (ST). It is generally accepted that the active sites on the K-Fe2O3 catalyst is potassium ferrite (KFeO2), which resides on the surface of a bulk magnetite phase and potassium polyferrite (K2Fe22O 34). This dehydrogenation reaction is typically performed in excess steam and the catalyst is known to experience short-term deactivation when the steam-to-hydrocarbon molar ratio (S/EB) is lowered. While possible causes for the deactivation phenomena are coking or reduction of the reactive site, the ...


Particle Size Prediction In Reactive Precipitation Processes , Jesse Ted Pikturna Jan 2004

Particle Size Prediction In Reactive Precipitation Processes , Jesse Ted Pikturna

Retrospective Theses and Dissertations

The aqueous reductive precipitation of palladium metal has been studied in semibatch stirred tank reactors. Scale-up from the bench scale to the 20 gallon scale has been studied using empirical scale-up rules. Some of the well-known difficulties and benefits associated with empirical methods for scale-up have been observed in this system.;In order to accurately predict particle size distributions (PSDs) in precipitation reactions, local variations in hydrodynamics, degree of supersaturation, and particle size distributions need to be accurately tracked. Discretized Population Balance (DPB) methods can accurately model precipitation process in well-mixed, uniform shear environments, but the implementation of DPB routines ...


Tnt Phytotransformation In Native And Genetically Modified Species: Significance Of Aromatic Hydroxylamines In The Metabolic Pathway , Murali Subramanian Jan 2004

Tnt Phytotransformation In Native And Genetically Modified Species: Significance Of Aromatic Hydroxylamines In The Metabolic Pathway , Murali Subramanian

Retrospective Theses and Dissertations

The presence and role of hydroxylamines in TNT transformation were ascertained in two axenic (microbe-free) hydroponic plant systems through high TNT feeding experiments and the use of different analytical detection schemes. Hydroxylamines were formed within 10 hours of TNT addition, and usually disappeared within 20 hours, displaying a high turnover rate due to their instability and high reactivity. Hydroxylamines were shown to add biomolecules to their functional group and thereby directly form conjugates. The 4-isomer of the hydroxylamine was detected in very high levels (up to 30% of initial TNT added) in a transgenic tobacco system that had a bacterial ...


Computational Fluid Dynamics Simulation Of Precipitation Processes , Liguang Wang Jan 2004

Computational Fluid Dynamics Simulation Of Precipitation Processes , Liguang Wang

Retrospective Theses and Dissertations

First, an experimental and computational investigation of the effects of local fluid shear rate on the aggregation and breakage of ~10 mum latex spheres suspended in an aqueous solution undergoing laminar and turbulent Taylor-Couette flow was carried out, according to the following program. First, computational fluid dynamics (CFD) simulations were performed and the flow field predictions were validated with data from particle image velocimetry experiments. Subsequently, the quadrature method of moments (QMOM) was implemented into the CFD code to obtain predictions for mean particle size that account for the effects of local shear rate on the aggregation and breakage. These ...


Theoretical And Experimental Explorations In Atomic Force Microscopy , Anil Gannepalli Jan 2004

Theoretical And Experimental Explorations In Atomic Force Microscopy , Anil Gannepalli

Retrospective Theses and Dissertations

Nanotechnology is the capability to build by controlling the arrangement of individual atoms and molecules. Such a technology would be founded on the ability to control, manipulate and investigate matter at the atomic scale. The invention of atomic force microscope (AFM) and the advances in micro-cantilever based scanning probe technology have significantly enhanced the experimental capability to probe and modify matter at the nanoscale. However, it is still severely limited in achieving the necessary bandwidth, sensitivity and resolution. To further the advances in this field an in-depth understanding of the nature and effects of the tip-sample interactions is imperative. A ...