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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

On-line dynamic optimization and control strategy for improving the performance of batch reactors

Mujtaba, Iqbal M., Arpornwichanop, A., Kittisupakorn, P. January 2005 (has links)
No / Since batch reactors are generally applied to produce a wide variety of specialty products, there is a great deal of interest to enhance batch operation to achieve high quality and purity product while minimizing the conversion of undesired by-product. The use of process optimization in the control of batch reactors presents a useful tool for operating batch reactors efficiently and optimally. In this work, we develop an approach, based on an on-line dynamic optimization strategy, to modify optimal temperature set point profile for batch reactors. Two different optimization problems concerning batch operation: maximization of product concentration and minimization of batch time, are formulated and solved using a sequential optimization approach. An Extended Kalman Filter (EKF) is incorporated into the proposed approach in order to update current states from their delayed measurement and to estimate unmeasurable state variables. A nonlinear model-based controller: generic model control algorithm (GMC) is applied to drive the temperature of the batch reactor to follow the desired profile. A batch reactor with complex exothermic reaction scheme is used to demonstrate the effectiveness of the proposed approach. The simulation results indicate that with the proposed strategy, large improvement in batch reactor performance, in term of the amount of a desired product and batch operation time, can be achieved compared to the method where the optimal temperature set point is pre-determined.
2

Relevancy Of Bipolar Word Pairs Across Product Categories: A Comparative Study Between Automobiles And The Iphone

Koprulu, Secil 01 December 2010 (has links) (PDF)
This thesis investigates human product interaction with a focus on the physical experience provided by products. The differences of users&#039 / perceptions are discussed according to the differences of bodily experiences served by products. The interaction with products is taken as a holistic experience phenomenon, and in order to assess users&#039 / understandings and evaluations about the experience with products / perceived pragmatic qualities, perceived hedonic qualities and elicited emotional reactions are analyzed. The research is conducted by means of surveys in order to compare users&#039 / perceptual differences in relation to two different product groups: automobiles and the iPhone, which differ in content of interaction, namely one serves a more physical (bodily) experience while the other a more virtual one. In order to find out the perceptual differences, verbal descriptions of perceived qualities and emotional states are used as measurement tools. A list consisting of bipolar word pairs in relation with pragmatic qualities, hedonic qualities and emotional reactions has been composed, and perceptual differences are investigated through the bipolar word pairs&#039 / relevancy levels according to the product. In addition, in order to show that meaning associations related to the same verbal description are context dependent, the meanings that are associated with the same word pairs for both products are investigated. Apparent differences between the relevant word pairs of the two different product groups have been observed, in addition with pragmatic qualities&#039 / higher relevancy scores compared to hedonic qualities and emotional reactions in defining users&#039 / interactions with products.
3

A pharmaceutical risk management model

Bui, Thu-Tam T. January 2006 (has links) (PDF)
Thesis (Ph. D.)--University of Oklahoma. / Bibliography: leaves 113-119.
4

Characterization of impact initiation of reactions in aluminum-based, intermetallic-forming reactive materials

Tucker, Michael D. 29 August 2011 (has links)
The objective of this work is to evaluate the reaction initiation characteristics of quasi-statically compressed intermetallic-forming aluminum-based reactive materials upon impact initiation, consisting of equi-volumetric tantalum-aluminum, tungsten-aluminum, nickel-aluminum, and pure aluminum. A modified Taylor rod-on-anvil setup was employed to determine the reaction initiation threshold kinetic energy and actual energy for plastic deformation and subsequent reaction. Experimental sample remnants were recovered and examined through X-ray diffraction to determine reaction products.The overall results indicate that of the various intermetallic-forming systems investigated, Ta+Al was the most reactive and was the only system where any reaction products were retrieved. While all of the intermetallic systems reacted in air, only Ta+Al and W+Al reacted in vacuum environment suggesting differences in reaction mechanisms influencing the reactivity of intermetallic mixtures. Based on the threshold energy for onset of reaction it appears that the Ta-Al compacts show reaction conditions below those required for reaction of Al in air. This combined with the fact that Ta+Al compacts also react in vacuum implies that the Ta+Al undergoes anaerobic intermetallic reaction while the other systems react with the oxidation of Al. The effect of compact packing density on the kinetic energy threshold for reaction initiation were also evaluated. It was observed more densely packed Ta+Al and Ni+Al powder compacts react more easily than less densely packed samples. While the effect of packing density is not as obvious in the case of pure Al and W+Al powder compacts. Finally, a particle size effect is seen on Ni+Al on samples of < 92% density where coarser (+325 -200 mesh) equal-volumetric powder mixtures were observed to be more reactive than finer Ni+Al (-325 mesh).

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