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1
Li, Fanxing. "CHEMICAL LOOPING GASIFICATION PROCESSES". The Ohio State University, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=osu1236704412.
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Lai, Sau Man. "Feasibility and flexibility in chemical process design /". View abstract or full-text, 2009. http://library.ust.hk/cgi/db/thesis.pl?CBME%202009%20LAI.
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Smith, G. J. "Dynamic simulation of chemical processes". Thesis, University of Cambridge, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.372635.
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Few, Julian William. "FTIR studies of chemical processes". Thesis, University of Oxford, 2013. http://ora.ox.ac.uk/objects/uuid:b7dbc587-fb9e-46de-8f04-44892fde0bf4.
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This thesis presents the study of a selection of gas phase chemical processes using time-resolved Fourier transform infrared (FTIR) emission spectroscopy. Such processes include molecular energy transfer, chemical reaction and photodissociation. The major focus of this thesis was the investigation of collisional energy transfer from the electronically excited states of NO and OH, with particular attention paid to the fate of the electronic energy. NO A2Σ+(v = 0) is prepared by laser excitation, pumping the overlapped Q1 and P21 band heads of the NO A-X (0,0) transition at 226.257 nm. The quenching of this state by O2 and CO2 was studied. Experiments were performed to investigate what channels contribute to the quenching process, the branching ratio of these different channels and the partitioning of energy among the various products. Quenching by O2 was found to proceed mostly through non-reactive channels. High vibrational excitation of NO X 2Π was observed, with population detected in v = 22, representing 79% of the available energy. The O2 product was found to be formed in more than one electronic state: the ground state, X 3Σ-g, and a high-lying electronically excited state, such as the A 3Σ+u, A' 3Δu or c 1Σ-u states. A reactive channel producing vibrationally excited NO2 was observed, but was found to be a minor process with an upper limit of 18% for the branching ratio. In contrast the quenching of NO A 2Σ+(v = 0) by CO2 was found to proceed predominately by reaction, with a branching ratio of 76 %. While emission from NO2 was observed, it was weak, and therefore it was concluded that the main reaction products were CO, O(3P) and NO X 2Π(v = 0). The nascent strong CO2 v3 emission band from the non-reactive channel exhibited a large red-shift from its fundamental position. This indicates that the CO2 vibrational distribution is significantly hotter than statistical. Investigations were then performed studying the quenching of NO A 2Σ+(v = 1) by NO and CO2, with both systems exhibiting similar characteristics to the quenching of the ground vibrational level of NO A 2Σ+. From comparison of the emission intensity of the CO fundamental and CO2 v3 mode following quenching of the v = 0 and 1 levels of the NO A 2Σ+ state, it was concluded that the branching ratio for reactive quenching was larger in the latter case. Secondly, experiments were performed to measure the rate constants for the quenching of NO A 2Σ+(v = 0) by the noble gases. The noble gases are inefficient quenchers of electronically excited NO and therefore careful experimental design was required to minimise the influence of impurities on the results. All the rate constants were found to be of the order of 10-14 cm3 molecule-1 s-1. The value for Xe was 50 times smaller than reported previously in the literature. In light of this new measurement, a re-analysis of experiments, performed previously in the group, on the electronic quenching of NO A 2Σ+(v = 0) by Xe was performed. A very hot vibrational distribution of NO X 2Π was obtained. Next, the collisional quenching of OH A 2Σ+(v = 0) by H2 was investigated. OH radicals were generated in situ by the photolysis of HNO3 at 193 nm, which were excited to the A 2Σ+(v = 0) state on the overlapped Q1(1) and P21(1) rotational lines at 307.935 nm. Reactive quenching was found to be the major pathway, in agreement with the literature. Copious emission from vibrationally excited water was observed. Comparison of this emission with theoretical calculations revealed a hotter distribution than predicted. It was concluded that the energy channelled into the vibrational modes of H2O is in excess of 60% of the available energy. Experiments performed with D2 allowed the non-reactive channel to be studied; a cold vibrational distribution of the OH X 2Π was observed. Finally the reaction between CN radicals and cyclohexane was studied. CN was generated by the photolysis of ICN at 266 nm. Prompt emission from HCN in the C-H stretching region was observed meaning the new bond was formed in a vibrationally excited state. Analysis of the emission revealed HCN was populated up to v3 = 2. Excellent agreement with the results of a theoretical study of the system was found.
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Singh, Lakhbinder. "Dynamic simulation of chemical processes". Thesis, Aston University, 1991. http://publications.aston.ac.uk/9731/.
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This thesis describes the design and implementation of an interactive dynamic simulator called DASPRII. The starting point of this research has been an existing dynamic simulation package, DASP. DASPII is written in standard FORTRAN 77 and is implemented on universally available IBM-PC or compatible machines. It provides a means for the analysis and design of chemical processes. Industrial interest in dynamic simulation has increased due to the recent increase in concern over plant operability, resiliency and safety. DASPII is an equation oriented simulation package which allows solution of dynamic and steady state equations. The steady state can be used to initialise the dynamic simulation. A robust non linear algebraic equation solver has been implemented for steady state solution. This has increased the general robustness of DASPII, compared to DASP. A graphical front end is used to generate the process flowsheet topology from a user constructed diagram of the process. A conversational interface is used to interrogate the user with the aid of a database, to complete the topological information. An original modelling strategy implemented in DASPII provides a simple mechanism for parameter switching which creates a more flexible simulation environment. The problem description generated is by a further conversational procedure using a data-base. The model format used allows the same model equations to be used for dynamic and steady state solution. All the useful features of DASPI are retained in DASPII. The program has been demonstrated and verified using a number of example problems, Significant improvements using the new NLAE solver have been shown. Topics requiring further research are described. The benefits of variable switching in models has been demonstrated with a literature problem.
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Inamdar, S. R. "Global optimization of chemical processes". Thesis(Ph.D.), CSIR-National Chemical Laboratory, Pune, 2012. http://dspace.ncl.res.in:8080/xmlui/handle/20.500.12252/2142.
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Yan, Ming. "Multi-objective, plant-wide control and optimization of chemical processes /". Thesis, Connect to this title online; UW restricted, 1996. http://hdl.handle.net/1773/9918.
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Weikel, Ross R. "Physical Transformations for Greener Chemical Processes". Diss., Georgia Institute of Technology, 2005. http://hdl.handle.net/1853/11654.
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Homogenous acid catalysts are prevalent throughout the chemical industry but all have the drawback of requiring post reaction neutralization and subsequent downstream removal of the product salt. The use of a base to neutralize the acid and the processing of the salt are ancillary to the process and the disposal of the salt is an environmental concern. The work presented here shows the use of alkylcarbonic acids, which form in situ with CO₂ pressure and neutralize on loss of CO₂ pressure rather than requiring a base. Thus CO₂ can be used to "switch" the acid on and off.
The properties of alkylcarbonic acids are explored to gain understanding of the mechanisms by which they act. The acids are also used to catalyze the synthesis of α-pinene, methyl yellow, and benzyl iodide. These reactions are examples of common acid catalyzed reactions where this technology could be implemented.
The second half of the work explores two other "switches". The first is using temperature to break an emulsion with a novel thermally cleavable surfactant. This technology has potential applications in a wide range of fields where surfactants are used including polymerization, oil recovery, and biosynthesis. The second is using CO₂ to liquefy a solid ionic compound to allow its use as a solvent. This would greatly increase the number of ionic species available for use in ionic liquid-CO₂ biphasic systems.
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Kondili, Emilia. "Optimal scheduling of batch chemical processes". Thesis, Imperial College London, 2011. http://hdl.handle.net/10044/1/8853.
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Ydstie, Birger Erik. "Robust adaptive control of chemical processes". Thesis, Imperial College London, 2011. http://hdl.handle.net/10044/1/8295.
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Morrell, Claire. "FTIR emission studies of chemical processes". Thesis, University of Oxford, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.326026.
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Sozio, John Charles. "Intelligent Parameter Adaptation for Chemical Processes". Thesis, Virginia Tech, 1999. http://hdl.handle.net/10919/34089.
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Reducing the operating costs of chemical processes is very beneficial in decreasing a company's bottom line numbers. Since chemical processes are usually run in steady-state for long periods of time, saving a few dollars an hour can have significant long term effects. However, the complexity involved in most chemical processes from nonlinear dynamics makes them difficult processes to optimize. A nonlinear, open-loop unstable system, called the Tennessee Eastman Chemical Process Control Problem, is used as a test-bed problem for minimization routines. A decentralized controller is first developed that stabilizes the plant to set point changes and disturbances.
Subsequently, a genetic algorithm calculates input parameters of the decentralized controller for minimum operating cost performance. Genetic algorithms use a directed search method based on the evolutionary principle of "survival of the fittest". They are powerful global optimization tools; however, they are typically computationally expensive and have long convergence times. To decrease the convergence time and avoid premature convergence to a local minimum solution, an auxiliary fuzzy logic controller was used to adapt the parameters of the genetic algorithm. The controller manipulates the input and output data through a set of linguistic IF-THEN rules to respond in a manner similar to human reasoning. The combination of a supervisory fuzzy controller and a genetic algorithm leads to near-optimum operating costs for a dynamically modeled chemical process.Master of Science
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Shen, Gwo-Chyau. "Adaptive inferential control for chemical processes /". The Ohio State University, 1987. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487329662147068.
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Chaudhary, Muhammad Nadeem Rafique. "Real time optimization of chemical processes". Thesis, Curtin University, 2009. http://hdl.handle.net/20.500.11937/1419.
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Due to current changes in the global market with increasing competition, strict bounds on product specifications, pricing pressures, and environmental issues, the chemical process industry has a high demand for methods and tools that enhance profitability by reducing the operating costs using limited resources. Real time optimization (RTO) strategies combine process control and economics, and have gone through much advancement during the last few decades. A typical real time optimization application is model based and requires the solution of at least three (usually) nonlinear programming problems, such as combined gross error detection and data reconciliation, parameter estimation and economic optimization. A successful implementation of RTO requires fast and accurate solution of these stated nonlinear programming problems.Current real time optimization strategies wait for steady state after a disturbance enters the process. If, during this wait, another disturbance enters into the system, it will increase the transition time significantly. An alternative, real time evolution (RTE), calculates the new set-points using only disturbance information and the new set-points are implemented in small step changes to a supervisory control system such as model predictive control (MPC) or can be implemented directly to the regulatory control layer. RTE ignores the important part of data screening therefore there is no surety that the calculated set-points represents current plant conditions. The main contribution of this thesis is to investigate the possibility of implementing new set-points without waiting for steady state. Two case studies, the Williams-Otto reactor and an integrated plant (the Williams-Otto reactor extended to include flash drum and large recycle stream), were used for analysis. The application of RTE, RTO and MPC were discussed and compared for the case studies to evaluate the performance in terms of the theoretical profit achieved.A new strategy, dynamic-RTO (D-RTO), based on modified dynamic data reconciliation (DDR) strategy and translated steady state model, was also developed for systems with significant bias and process noise. In the D-RTO strategy, the residual terms of the steady state model were calculated from the reconciled values. These residual terms were translated subsequently into the steady state model. Due to the translation there is no need for calculating set-point changes in small steps. The formulation of the DDR strategy is based on control vector parameterization techniques. D-RTO was compared with RTE and RTO for the two case studies. The results obtained show that RTE can lead to an unstable control if used without taking into account process and controller dynamics. For measurements having bias, the DDR strategy can be used with the assumption that the variables with bias are unmeasured and are calculated implicitly. The D-RTO strategy is able to deal with constant and changing bias, and is able to decrease profit losses during transitions. D-RTO is a good alternative to steady state RTO, for processes with frequent disturbances, where RTO implementation due to its steady state nature may not be justifiable.
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Fien, Gert-Jan A. F. "Studies on process synthesis and process integration". Diss., This resource online, 1994. http://scholar.lib.vt.edu/theses/available/etd-08032007-102242/.
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Shi, Ruijie. "Subspace identification methods for process dynamic modeling /". *McMaster only, 2001.
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Padley, Mark Andrew. "Incorporating operability measures into the process synthesis stage of design". Phd thesis, Department of Chemical Engineering, 1991. http://hdl.handle.net/2123/5996.
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Eggersmann, Markus. "Analysis and support of work processes within chemical engineering design processes /". Düsseldorf : VDI-Verl, 2005. http://bvbr.bib-bvb.de:8991/F?func=service&doc_library=BVB01&doc_number=013342934&line_number=0001&func_code=DB_RECORDS&service_type=MEDIA.
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Amale, Amit. "New approach to the design and optimization on energy efficient chemical processes /". View online ; access limited to URI, 2008. http://0-digitalcommons.uri.edu.helin.uri.edu/dissertations/AAI3314439.
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Jarvis, Richard Barry. "Robust dynamic simulation of chemical engineering processes". Thesis, Imperial College London, 1993. http://hdl.handle.net/10044/1/7309.
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Saunders, Mark. "Chemical processes studied by time-resolved FTIR". Thesis, University of Oxford, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.491975.
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This thesis has applied the time-resolved FTIR emission technique to the study of a number of gas phase cheinical processes, including photodissociation, chemical reaction and energy transfer. Two particular types of species are considered: vibrationally excited NO, formed from photolysis, reaction and energy transfer pathways, and organic radical compounds formed from photolysis and involved in secondary reaction processes. Vibrationally excited NO has been observed as one of the reaction products following the photolysis of N02 over a range of wavelengths in the region 193 - 327 nm. Emission from the fundamental and first overtone bands was analysed to obtain the nascent vibrational distribution at each wavelength considered. The nascent vibrational distribution was found to be strongly inverted and wavelength dependent. Photolysis at A > 244 nm proceeds via one reaction pathway; 1 A>244nm )NO+Oep) (1) and the NO(v) distribution is of atmospheric importance in determining the global concentrations of NO measured from satellite emission studies. There is a smooth trend in the inverted distributions with increasing photon energy. Nascent populations were used to produce a new model to predict the wavelength dependence of the nascent populations of NO(v) formed following photolysis of N02 in the range 265 - 370 nm. Such work has been shown to provide useful new information for atmospheric models of global concentrations of NO. Atmospheric models of NO concentrations also require input parameters for the rates of relaxation of NO(v) in collision with quenching molecules, in particular 02. The rate constants for vibrational quenching of NO(v = 1 - 16) in collisions with a number of species have been measured. Vibrationally excited NO was produced by both the 193 nm photolysis of N02 and the reaction of OeD) with N20, initiated by the 193 nm photolysis of N20. Quenching rates were measured for collisions with O2, He, NO and CO2. The vibrational distribution of NO(v) formed following photolysis of N02 at 193 nm was confirmed to be bimodal with a secondary maximum at v = 14 allowing new rates of relaxation of highly vibrationally excited NO to be determined due to the relatively large nascent populations of these levels. At A< 244 nm at second reaction channel for N02 photolysis opens up and in order to assess the contribution of this channel to the overall distribution at such wavelengths a new nascent distribution was determined following photolysis at 226 nm. The distribution was found to be bimodal and could qualitatively be described by the sum of the Oep) and OeD) channels. Vibrationally excited NO was also formed following energy transfer from NO A z:E+(v = 0), which was achieved by 226 nm pumping of ground state NO. Nascent vibrational distributions were determined for a variety of collision partners and NO was shown to be populated up to at least v = 20. The distributions obtained varied with the collision partners: NO, CO, COz and Ar. Distributions of ground state NO(v) were also acquired under conditions such that the internal energy in the products was governed by the emission coefficients. Comparison of distributions obtained by collision and fluorescence and those predicted from the emission coefficients allowed a purely collisional NO(v) distribution to be estimated when NO and CO were the quenching molecules. Emission was also observed from high vibrational modes of CO and COz indicating a direct energy transfer from NO A z:E\v = 0). Argon was found to not significantly affect the distribution at the pressures employed but afforded a dramatic increase in intensity from NO(v) that was shown to be due to hole burning and subsequent collisional hole filling. The second part of this thesis describes the generation and reactions of organic radical species. The photolysis of vinyl bromide and vinyl chloride at 193 urn was considered and nascent vibrational populations of the HBr and HCI products have been measured and found to be indicative of a three-centre formation mechanism. Secondary reaction products of the vinyl radical (CZH3) produced from this photolysis process have also been considered and mechanisms for their formation proposed. The presence of buffer gas has been shown to generate new features which have been assigned to vibronic emission from the secondary reaction product CzH. Products of the reaction of Oz with the vinyl radical, formed from the 193 nm photolysis of vinyl bromide and vinyl chloride, have been identified. In particular the existence two primary reaction channels have been confirmed by the assignment of emission from CO2, HCO and HzCO, and the mechanism of one secondary reaction channel has been proposed by analysing the kinetics of emission from CO(v). In addition a new reaction channel has been proposed by considering emission from CzHz. A qualitative branching ratio between these three reaction channels has been proposed. The reaction of CZH3 with O2 is of significance to combustion processes and a rate constant for the process has been determined to be 9.5 x 1O,tZ cm3 molecule,l S'I by assessing the kinetics of emission from HzCO. As a comparison to the generation of simple unsaturated free radicals, such as the vinyl radical, the photolysis of acetone at 266 nm to generate the simple saturated methyl radical was investigated. Primary reaction products were identified as the CH3 and CH3CO radicals and emission was observed in the C-H stretching region that was assigned on the basis of its kinetics to the methyl radical recombination product CZH6• CO(v = 1 - 6) was also observed as a secondary product of the process and attributed to photolysis of CH3CO on account of its significantly hotter nascent vibrational distribution than that obtained in previous studies at 193nm.
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Morrison, Marc. "Chemical processes studied by time resolved FTIR". Thesis, University of Oxford, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.414235.
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Oum, Kawon. "Laser studies of gas phase chemical processes". Thesis, University of Oxford, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.318810.
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Papazoglou, Michael. "Multivariate statistical process control of chemical processes". Thesis, University of Newcastle Upon Tyne, 1998. http://hdl.handle.net/10443/408.
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The thesis describes the application of Multivariate Statistical Process Control (MSPC) to chemical processes for the task of process performance monitoring and fault detection and diagnosis. The applications considered are based upon polymerisation systems. The first part of the work establishes the appropriateness of MSPC methodologies for application to modern industrial chemical processes. The statistical projection techniques of Principal Component Analysis and Projection to Latent Structures are considered to be suitable for analysing the multivariate data sets obtained from chemical processes and are coupled with methods and techniques for implementing MSPC. A comprehensive derivation of these techniques are presented. The second part introduces the procedures that require to be followed for the appropriate implementation of MSPC-based schemes for process monitoring, fault detection and diagnosis. Extensions of the available projection techniques that can handle specific types of chemical processes, such as those that exhibit non-linear characteristics or comprise many distinct units are also presented. Moreover, the novel technique of Inverse Projection to Latent Structures that extends the application of MSPC-based schemes to processes where minimal process data is available is introduced. Finally, the proposed techniques and methodologies are illustrated by applications to a batch and a continuous polymerisation process.
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Hong, Tao. "Non-linear predictive control of chemical processes". Thesis, University of Newcastle Upon Tyne, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.245078.
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Zhu, Kechen, i Kechen Zhu. "Chemical and Microbial Processes for Rhodium Recovery". Thesis, The University of Arizona, 2017. http://hdl.handle.net/10150/625349.
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This is the first report that demonstrates the ability of anaerobic methanogenic granular sludge to reduce Rh(III) to Rh(0). Recovery of rhodium(Rh) during anaerobic incubations under abiotic and biotic condition with different electron donors was studied. H2 and formate reduced Rh(III) to Rh(0) nanoparticles(NPs) in the absence of microorganisms. However, the presence of microorganism was crucial for Rh(III) reduction with ethanol. Results of X-ray powder diffraction (XRD) and transmission electron microscopy (TEM) confirmed the formation of Rh(0) NPs and indicated the localization and morphology of the formed Rh(0) NPs varied with electron donor utilized. Rh(III) reduction with H2 and ethanol obeyed 1st order kinetics. Rh(III) caused a moderate inhibition to methanogenesis. Rh(III) reduction often ceased before coming to completion but this effect is not due to unfavorable thermodynamics. A hypothesis was developed which ascribes the biological reduction of Rh(III) with ethanol as being due to the biological formation of H2 (that subsequently chemically reacts with Rh). The results obtained indicate the potential of utilizing anaerobic granular sludge bioreactor technology as a practical and promising option in Rh(III) recovery.
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Rashid, Muhammad. "Stability and dynamic operability analysis of chemical processes". Title page, table of contents and abstract only, 1988. http://web4.library.adelaide.edu.au/theses/09ENS/09ensr224.pdf.
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Hamann, Stephan [Verfasser]. "On aspects of chemical processes in surface modification plasma processes / Stephan Hamann". Greifswald : Universitätsbibliothek Greifswald, 2015. http://d-nb.info/1080392726/34.
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Bai, Shuanghua. "Data reconciliation for dynamic processes". Thesis, University of Ottawa (Canada), 2006. http://hdl.handle.net/10393/29279.
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In a modern chemical plant, the implementation of a distributed control system leads to a large number of measurements that are available online for process monitoring, control, optimization and management decision making. Unfortunately, these measurements often contain errors that degrade the information quality obtained from the raw data. This thesis is dedicated to the development of dynamic data reconciliation (DDR) algorithms for the optimal estimation of variables in dynamic processes. More importantly, the DDR algorithms were implemented within the structures of feedback control loops, and the performance of the DDR algorithms as well as the controllers was quantitatively assessed via a series of process simulations. The DDR algorithms, acting as digital filters, were compared to commonly used filters, such as the exponentially weighted moving average (EWMA), moving average (MA), Kalman and extended Kalman filters. Methodologies to use the DDR algorithms to deal with autocorrelated noise were also investigated.
The DDR algorithms integrate information from both measurements and process dynamic models such that, at each sampling time, the estimates obtained by the DDR algorithms provide more precise representations of the current state of the process. Three DDR algorithms were developed, namely, nonlinear programming (NLP) based DDR, predictor-corrector based DDR, and autoassociative neural network (AANN) based DDR.
Evaluations of these DDR algorithms were conducted via simulations of three chemical processes, namely a cylindrical storage tank, a spherical storage tank and a binary distillation column. Results demonstrated that the DDR algorithms are efficient and effective tools for the estimation of dynamic processes. They perform significantly better than the EWMA and MA filters. Furthermore, compared to the Kalman filter, the DDR algorithm is easier to understand and to implement. Studies also showed that the structure of process models has considerable impact on the performance of the DDR. The use of the DDR algorithms embedded in feedback control loops significantly enhanced the controller performance. For example, the cost function of the control system in the distillation column was reduced by 28∼39% when linear, adaptive linear and nonlinear DDR algorithms were used. The cost function of the controller in the cylindrical storage tank was reduced by 46% using DDR, while it was reduced by 33% when using a EWMA filter.
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Sharma, Sandeep Ph D. Massachusetts Institute of Technology. "Predictive modeling of combustion processes". Thesis, Massachusetts Institute of Technology, 2009. http://hdl.handle.net/1721.1/54583.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemical Engineering, 2009.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 161-169).
Recently, there has been an increasing interest in improving the efficiency and lowering the emissions from operating combustors, e.g. internal combustion (IC) engines and gas turbines. Different fuels, additives etc. are used in these combustors to try to find the optimal operating conditions and fuel combination which gives the best results. This process is ad-hoc and costly, and the expertise gained on one system cannot easily be transfered to other situations. To improve this process a more fundamental understanding of chemistry and physical processes is required. The fundamental constants like rate coefficients of elementary reactions are readily transferable enabling us to use results from one set of experiments or calculations in a different situation. In our group we have taken this approach and developed the software Reaction Mechanism Generator (RMG), which generates chemical mechanism for oxidation and pyrolysis of a given fuel under a set of user-defined physical conditions. RMG uses group additivity values to generate thermochemistry of molecules and has a database of rate coefficients of elementary reactions. These two sets of data are used to generate chemical kinetic mechanism in a systematic manner. The reaction mechanisms generated by RMG are purely predictive and elementary rate coefficient from any reliable source can be added to RMG database to improve the quality of its predictions. The goal of my thesis was two fold, first to extend the capabilities and database of RMG and to release it as an open source software for the chemical kinetic community to use.
(cont.) The second was to take a practical system of interest and use RMG to generate the chemical mechanism and thereby demonstrate the utility of RMG in generating predictive chemical mechanisms for practical situations. As a part of the second step our hope was to generate new chemical insights into soot formation processes which are of great interest. The three most important contributions of the thesis are listed below. 1. My work with RMG has resulted in order of magnitude improvements in the cpu and memory usage of RMG and it has added many useful features to RMG like ac- curate sensitivity analysis for better interpreting the final mechanism. I have also worked on extending the database of RMG, by adding thermochemistry of ringed species that cannot be treated adequately by group additivity. Also kinetic rate rules for intramolecular-H-migration reactions in OOQOOH molecules were added to RMG database, which are important in predicting the low temperature oxidation of alkanes. 2. Recently there have been considerable advances in the methodology for rate coefficient calculations for loose transition states, i.e transition states that are not saddle points. These type of transition states are encountered often in radical-radical reactions. In addition to these advances there has been significant progress in accurate calculation of the pressure dependent rate coefficients for complicated potential energy surfaces with multiple wells and multiple product channels. The method is based on the master equation formulation of the problem. These detailed equations are then appropriately coarse-grained to calculate the phenomenological rate coefficients.
(cont.) I have used these state of the art techniques to calculate the rate coefficients for the formation of various aromatic species like benzene and styrene. The rate coefficients predicted by these methods were tested under certain conditions and are in good agreement with experimental data. 3. Finally to model a two-dimensional diffusion flame we have developed a solver that is able to solve a complicated set of highly coupled differential equations in an efficient manner to give accurate results. The solver in conjunction with chemistry that is developed using techniques mentioned in the last two points is used to solve the mole fraction profiles in the diffusion flame. The results of the simulations are compared to the experimental measurements and this process gives us insight into soot formation in diffusion flames.
by Sandeep Sharma.
Ph.D.
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Merchant, Tushar Praful. "Modelling of rapid thermal processes". Thesis, Massachusetts Institute of Technology, 1995. http://hdl.handle.net/1721.1/11784.
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Lloyd, Michael C. "Novel materials for membrane separation processes". Thesis, Aston University, 1995. http://publications.aston.ac.uk/9680/.
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The aim of this work was to synthesise a series of hydrophilic derivatives of cis-1,2-dihydroxy-3,5-cyclohexadiene (cis-DHCD) and copolymerise them with 2-hydroxyethyl methacrylate (HEMA), to produce a completely new range of hydrogel materials. It is theorised that hydrogels incorporating such derivatives of cis-DHCD will exhibit good strength and elasticity in addition to good water binding ability. The synthesis of derivatives was attempted by both enzymatic and chemical methods. Enzyme synthesis involved the transesterification of cis-DHCD with a number of trichloro and trifluoroethyl esters using the enzyme lipase porcine pancreas to catalyse the reaction in organic solvent. Cyclohexanol was used in initial studies to assess the viability of enzyme catalysed reactions. Chemical synthesis involved the epoxidation of a number of unsaturated carboxylic acids and the subsequent reaction of these epoxy acids with cis-DHCD in DCC/DMAP catalysed esterifications. The silylation of cis-DHCD using TBDCS and BSA was also studied. The rate of aromatisation of cis-DHCD at room temperature was studied in order to assess its stability and 1H NMR studies were also undertaken to determine the conformations adopted by derivatives of cis-DHCD. The copolymerisation of diepoxybutanoate, diepoxyundecanoate, dibutenoate and silyl protected derivatives of cis-DHCD with HEMA, to produce a new group of hydrogels was investigated. The EWC and mechanical properties of these hydrogels were measured and DSC was used to determine the amount of freezing and non-freezing water in the membranes. The effect on EWC of opening the epoxide rings of the comonomers was also investigated
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Franklin, Valerie J. "Lipoidal species in ocular spoilation processes". Thesis, Aston University, 1990. http://publications.aston.ac.uk/9738/.
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Tear component deposition onto contact lenses is termed `spoilation' and occurs due to the interaction of synthetic polymers with their biological fluid environment. Spoilation phenomena alter the physico-chemical properties of hydrophilic contact lenses, diminishing the optical properties of the lens; causing discomfort and complications for the wearer. Eventually these alterations render the lens unwearable. The primary aim of this interdisciplinary study was to develop analytical techniques capable of analysing the minute quantities of biological deposition involved, in particular the lipid fraction. Prior to this work such techniques were unavailable for single contact lenses. It is envisaged that these investigations will further the understanding of this biological interfacial conversion. Two main analytical techniques were developed: a high performance liquid chromatography (HPLC) technique and fluorescence spectrofluorimetry. The HPLC method allows analysis of a single contact lens and provided previously unavailable valuable information about variations in the lipid profiles of deposited contact lenses and patient tear films. Fluorescence spectrophotofluorimetry is a sensitive non-destructive technique for observing changes in the fluorescence intensity of biological components on contact lenses. The progression and deposition of tear materials can be monitored and assessed for both in vivo and in vitro spoiled lenses using this technique. An improved in vitro model which is comparable to tears and chemically mimics ocular spoilation was also developed. This model allows the controlled study of extrinsic factors and hydrogel compositions. These studies show that unsaturated tear lipids, probably unsaturated fatty acids, are involved in the interfacial conversion of hydrogel lenses, rendering them incompatible with the ocular microenvironment. Lipid interaction with the lens surface then facilitates secondary deposition of other tear components. Interaction, exchange and immobilisation (by polymerisation) of the lipid layer appears to occur before the final and rapid growth of more complex, insoluble discrete deposits, sometimes called `white spots'.
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Lamb, David R. "New reaction systems for environmentally conscious chemical processes". Diss., Georgia Institute of Technology, 1998. http://hdl.handle.net/1853/30075.
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Ruedisueli, Robert Louis. "Cyclically optimized electrochemical processes /". Thesis, Connect to this title online; UW restricted, 1997. http://hdl.handle.net/1773/10576.
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Alpay, Esat. "Rapid pressure swing adsorption processes". Thesis, University of Cambridge, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.333256.
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Peterson, Andrew A. "Biomass reforming processes in hydrothermal media". Thesis, Massachusetts Institute of Technology, 2009. http://hdl.handle.net/1721.1/51678.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemical Engineering, 2009.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Includes bibliographical references (p. 240-258).
While hydrothermal technologies offer distinct advantages in being able to process a wide variety of biomass feedstocks, the composition of the feedstock will have a large effect on the processing employed. This thesis characterizes the role of two major components of biomass, salts and proteins, that if dealt with intelligently can create valuable byproducts, but if dealt with inefficiently can cause processes to fail or run sub-optimally. In supercritical-water, most ionic species exhibit only sparing solubility. Thus, in the supercritical-water gasification of biomass, a supercritical-water reverse-flow vessel (RFV) may be employed to precipitate the salts from the biomass before the biomass is brought into contact with catalysts. However, these vessels are subject to blockage, and flow characterization within the vessels has largely been unknown. Therefore, the technique of neutron radiography is introduced to the supercritical-water processing field in order to characterize the behavior within these RFVs. This allows for non-invasive, in situ, real-time measurements of precipitation phenomena within thick-walled vessels. Two methods that provide complimentary information were developed to observe the precipitation behavior of salts from supercritical water. In the first method ("normalphase" radiography), the salts have a lower attenuation coefficient than the continuous 1H2O phase. This allowed for the visualization of major blockages, buildups of salts at the walls, and flow pattern changes. By using the strongly attenuating 1H2O form of water, fluid density changes resulting from flow pattern changes were also apparent.
(cont.) In the second method ("reverse-phase" radiography), strongly attenuating salts, such as those containing boron, were employed in a continuous phase of D2O, which has a weak neutron attenuation coefficient. In this manner, the onset of precipitation events could be seen with finer resolution. The neutron radiographical method was also employed to perform an elegant 1H2Oin-D2O tracer study of the fluid mechanics within the RFV, in which a stream of water that spans its critical temperature undergoes a reversing flow pattern. The flow was found to penetrate deep into the vessel and to mix thoroughly with the contents of the vessel, presumably because of the strong buoyant forces generated by heat at the walls. In the absence of wall heating, the flow was observed to reverse at a point much nearer to the top of the vessel. Also, as compared to comparable conditions at subcritical pressures, the supercritical jet was found to be more diffuse and to penetrate the vessel at a lower velocity. A jet entrainment model was derived to describe the flow within the vessel. Due to the near-critical conditions in the vessel, the model was developed without the Boussinesq approximation or the density deficiency formulation commonly applied to such models. The model was solved numerically and was found to provide excellent agreement with the neutron radiographical data for the two cases studied: an isothermal case and a case in which the temperatures spanned the critical point of water. In the isothermal limit, the model accurately predicted the jet reversal point.
(cont.) In the case with temperatures that spanned the critical point, the model accurately predicted that the jet would not fully reverse before reaching the bottom of the vessel. The model also predicted the characteristic decay time of a tracer within the vessel with near-perfect accuracy. Proteins are a second constituent of biomass that require special treatment in the development of hydrothermal processes. Industrial and research laboratory reports have indicated that the presence of proteins may create processing conditions that lead to equipment fouling and reduced gasification yields in hydrothermal processing. In studies on the interaction between glycine and glucose as model compounds at 250C and 10 MPa, strong kinetic and qualitative evidence is presented that a Maillard-type reaction occurs in hydrothermal processing. This reaction, which is very common at the lower temperatures encountered in food and medicinal chemistry, is known to lead to the formation of polymeric material that may be desirable for color and flavor generation in food processing, but is generally undesirable in hydrothermal processing, since these polymers will act to foul process equipment. Glucose and glycine were found to strongly influence the reaction pathway of the other compound, and the resulting reactor effluent had UV absorbances typical of Maillard reaction products. Compounds with the same functional groups, a primary amine and a carbonyl group, were substituted for glucose and glycine and were found to have similar effects.
(cont.) Also, the degradation pathway of glucose was found to be altered, with the significant product hydroxymethylfurfural being suppressed with the addition of glycine. The reactive form of glucose is the acyclic, aldehydoglucose form. Glucose can also exist as an unreactive, cyclic form, which dominates at room temperature, making up over 99.99% of the aqueous equilibrium composition. However, this equilibrium is unknown at elevated temperatures and pressures. A preliminary computational chemistry study was undertaken to predict this equilibrium under hydrothermal conditions. The acyclic form was predicted to rise to be of comparable prevalence to the cyclic forms. The study indicates that this was caused by two main effects, a change in the relative stability imparted by the decreased dielectric constant of water, and by an entropic effect in which the much larger number of conformers that are possible in the acyclic state become more energetically populated at higher temperatures.
by Andrew A. Peterson.
Ph.D.
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Mehrabi, M. Reza. "Modeling transport processes in directional solidification". Thesis, Massachusetts Institute of Technology, 1994. http://hdl.handle.net/1721.1/11999.
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Yang, Ming Ph D. Massachusetts Institute of Technology. "Stochastic processes in T-cell signaling". Thesis, Massachusetts Institute of Technology, 2012. http://hdl.handle.net/1721.1/76488.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemical Engineering, 2012.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 89-93).
T cells are orchestrators for adaptive immunity. Antigen recognition by T cells is mediated by the interactions between T-cell receptors (TCRs) and peptide-MHC (pMHC) molecules. How T cells can translate stimulatory external cues (e.g., TCRpMHC interactions where the peptides are derived from foreign proteins) to functional responses (e.g., proliferation), while not responding to self-pMHC has been a puzzle for decades. The ability to discriminate foreign antigens from self antigens demands extraordinary intricacy for the design and operation of signaling pathways. This problem is a special challenge since fluctuations at the microscopic level are ubiquitous in biochemical networks, due to stochastic nature of reactions and uncertainties in protein expressions. The prevalence of noise imposes further challenges for T cells to deliver biological functions reliably. The overarching theme of this thesis is to understand the role of stochasticity in T-cell signaling. Four problems have been selected for presentation in this thesis: 1. Fluctuation-driven transitions can drive cellular systems out of stable states and lead to spurious responses. We proposed a theoretical and computational framework to identify key reactions or species that are responsible for regulating such stochastic transitions. The identification of these critical components for network stability not only pinpoints key deleterious protein mutations, but also helps intelligently select drug targets. The semi-analytical method we derived using large-deviation theory and calculus of variations agrees well with computational costly brute-force simulations. Additionally, our framework unveils qualitative characteristics of key reactions regulating stochastic transitions. We believe that we have developed the first method to carry out fully stochastic sensitivity analyses using analytical calculations. 2. In collaboration with Dr. Jeroen Roose's lab at UCSF, we investigated the roles of RasGRP and SOS in the activation of ERK and P38 MAP kinase pathways. We extended established computational models developed in our lab and predicted that SOS' allosteric pocket is important for the magnitude and bimodal pattern of ERK activation, which was confirmed experimentally. The synergy between computational modeling and experimental studies enabled us to propose mechanistic models that incorporate features such as co-operativity and non-linearity thresholding to study P38 activation. These models were consistent with the experimental findings that SOS is preferentially more important than RasGRP for Rac-P38 activation and SOS' allosteric pocket has little effect on Rac-P38 pathways, and also generated numerous experimentally testable hypotheses. 3. While rare events, such as escapes from stable basins, take a long time (waiting time) to occur, they take little time to complete once they have started. We showed that for Markov processes characterized by detailed balance, successful transitions, on average, complete exactly as quickly as transitions in the opposite (non-rare) direction. We first provide a general proof by invoking time reversibility, and then elaborate the proof by considering two specific dynamics, namely, continuous-time Markov Chains with detailed balance and one-dimensional Langevin Dynamics. We employ ideas from measure theory and stochastic calculus. We conclude that rare events, once they happen, happen quickly, and speculate about extensions to nonequilibrium systems, such as viral escape. 4. While microscopic fluctuations complicate reliable functioning of biochemical networks, stochastic noise also offers enormous information about the underlying network that generates such noise. We present an effort to exploit the non-random structure of random noise for network topology identification. In particular, we applied linear noise approximations to two three-node network motifs, namely, incoherent feed-forward loop (IFF) and negative feedback loop (NFB), and obtained correlation functions governing the fluctuations of species copy numbers at steady state. We identified two signatures that can be used to discriminate IFF from NFB. This endeavor represents a first step toward understanding how, and to what extent, time-series data with fine time and length resolutions can be used to infer network structures.
by Ming Yang.
Ph.D.
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Crowther, Timothy Guy. "Application of chemical acoustic emission to industrial processes". Thesis, University of British Columbia, 1991. http://hdl.handle.net/2429/29804.
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This thesis reports on two chemical acoustic emission studies of importance to Canadian Industry. The first demonstrated that the rate of evolution of hydrogen and oxygen from electrodes in an electrolysis cell may be conveniently monitored via its ultrasonic acoustic emission, in a non-intrusive manner. The apparatus used in this work consisted of a nickel anode, a stainless steel cathode, and a saturated calomel reference electrode, all situated in a three-chamber cell containing sodium hydroxide electrolyte solutions of various concentrations. The potential necessary for evolution of both hydrogen and oxygen was conclusively determined by the onset of bursts of acoustic emission. Individual acoustic emission signals, captured using a broadband transducer mounted on the working electrode, contained frequencies from 16 kHz to as high as 800 kHz. These were correlated with the release of streams of bubbles from the electrode's surface, both visually and via a chart recorder trace of peak acoustic intensity vs. time. Trends in several time-domain signal descriptors were observed with an increase in the applied voltage. Acoustic power spectra were obtained by averaging spectra from many acoustic signals. Estimates of rate of emission were made by integration of the peak acoustic level. The effects of applied potential and electrolyte concentration on the multiple bursts of acoustic emission were characterized and are presented as a system response surface. Increasing the applied potential resulted in greater rates of bubble emission, which increased the intensity of acoustic emission, but produced, essentially, an identical acoustic power spectrum. The extent of acoustic emission at high concentrations (2.0 M) and high applied potentials (3.0 - 4.0 V) was less than expected, which suggested a decrease in efficiency under these conditions. Evolution of gas from the electrolysis was compared with the root mean square (RMS) voltage of the acoustic signal. The acoustic RMS was found to correlate linearly with gas volume produced, and consequently it correlated linearly with current measurements. Further studies indicate that the formation of oxides on a clean electrode surface was accompanied by limited acoustic
activity, but no such emissions were found for electrodes in which the oxide coating was already present.
The second study sought to improve the method that industry uses to determine the sensitivity of compounds to impact. This method is particularly important in measuring the safety of handling explosive compounds in transport, and in storage. The apparatus used presently involves the dropping of a weight from a height onto a small sample, which is confined in a specially designed enclosure. A positive result only occurs when enough energy was supplied to cause an explosion. Whether a result is positive or negative is somewhat open to the interpretation of the operator. Signs of a positive result include smoke, piercing of a diaphragm, or the formation of a dark residue within the sample enclosure. The amount of potential energy (height x weight) required to cause a positive result in at least 50% of tests is termed the sensitivity value. Used in this conventional fashion, the instrument produced a single YES/NO decision per experiment. Many experiments were required to characterize each sample, in what is a very tedious procedure. In this present work it is shown that acoustic emission can be used to effectively monitor controlled explosive reactions occurring within the drop weight tester sample cavity. The acoustic emission resulting from the impact was captured using a broadband transducer mounted on a clip, which rested on the sample holder. Frequencies from 100 kHz to 1 MHz were captured. This has resulted in an automatic method for distinguishing between a positive and a negative result in calibration and solid sample tests. Spectrogram (plots time vs. frequency emission) analysis suggests that acoustic emission may be used to probe the mechanism of the explosion within the sample container. The high irrepeatability of results for the nitromethane samples was due to the piercing of the "O-ring" surrounding the sample, rather than the expected rupture of the diaphragm situated above it. The results show that better design of the present drop weight apparatus must be undertaken to improve the reproducibility. Acoustic emission will provide a useful means to quantify that improvement.Science, Faculty of
Chemistry, Department of
Graduate
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Zhu, Jianye. "Integrated process design and control of chemical processes". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape17/PQDD_0009/NQ34864.pdf.
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Hocking, Damien. "Object-oriented simulation of chemical and biochemical processes /". Title page and contents only, 1997. http://web4.library.adelaide.edu.au/theses/09PH/09phh6847.pdf.
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Amaya, John. "Numerical study of combustion chemical vapor deposition processes". Thesis, Georgia Institute of Technology, 2000. http://hdl.handle.net/1853/12991.
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Grunnet-Jepsen, Helene. "A fundamental study of foaming in chemical processes". Thesis, University of Oxford, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.389215.
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Horne, Simon James. "A novel hybrid approach to modeling chemical processes". Thesis, University of Newcastle Upon Tyne, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.531756.
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Kandiah, Sivasothy. "Fuzzy model based predictive control of chemical processes". Thesis, University of Sheffield, 1996. http://etheses.whiterose.ac.uk/3029/.
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The past few years have witnessed a rapid growth in the use of fuzzy logic controllers for the control of processes which are complex and ill-defined. These control systems, inspired by the approximate reasoning capabilities of humans under conditions of uncertainty and imprecision, consist of linguistic 'if-then' rules which depend on fuzzy set theory for representation and evaluation using computers. Even though the fuzzy rules can be built from purely heuristic knowledge such as a human operator's control strategy, a number of difficulties face the designer of such systems. For any reasonably complex chemical process, the number of rules required to ensure adequate control in all operating regions may be extremely large. Eliciting all of these rules and ensuring their consistency and completeness can be a daunting task. An alternative to modelling the operator's response is to model the process and then to incorporate the process model into some sort of model-based control scheme. The concept of Model Based Predictive Control (MB PC) has been heralded as one of the most significant control developments in recent years. It is now widely used in the chemical and petrochemical industry and it continues to attract a considerable amount of research. Its popularity can be attributed to its many remarkable features and its open methodology. The wide range of choice of model structures, prediction horizon and optimisation criteria allows the control designer to easily tailor MBPC to his application. Features sought from such controllers include better performance, ease of tuning, greater robustness, ability to handle process constraints, dead time compensation and the ability to control nonminimum phase and open loop unstable processes. The concept of MBPC is not restricted to single-input single-output (SISO) processes. Feedforward action can be introduced easily for compensation of measurable disturbances and the use of state-space model formulation allows the approach to be generalised easily to multi-input multi-output (MIMO) systems. Although many different MBPC schemes have emerged, linear process models derived from input-output data are often used either explicitly to predict future process behaviour and/or implicitly to calculate the control action even though many chemical processes exhibit nonlinear process behaviour. It is well-recognised that the inherent nonlinearity of many chemical processes presents a challenging control problem, especially where quality and/or economic performance are important demands. In this thesis, MBPC is incorporated into a nonlinear fuzzy modelling framework. Even though a control algorithm based on a 1-step ahead predictive control strategy has initially been examined, subsequent studies focus on determining the optimal controller output using a long-range predictive control strategy. The fuzzy modelling method proposed by Takagi and Sugeno has been used throughout the thesis. This modelling method uses fuzzy inference to combine the outputs of a number of auto-regressive linear sub-models to construct an overall nonlinear process model. The method provides a more compact model (hence requiring less computations) than fuzzy modelling methods using relational arrays. It also provides an improvement in modelling accuracy and effectively overcomes the problems arising from incomplete models that characterise relational fuzzy models. Difficulties in using traditional cost function and optimisation techniques with fuzzy models have led other researchers to use numerical search techniques for determining the controller output. The emphasis in this thesis has been on computationally efficient analytically derived control algorithms. The performance of the proposed control system is examined using simulations of the liquid level in a tank, a continuous stirred tank reactor (CSTR) system, a binary distillation column and a forced circulation evaporator system. The results demonstrate the ability of the proposed system to outperform more traditional control systems. The results also show that inspite of the greatly reduced computational requirement of our proposed controller, it is possible to equal or better the performance of some of the other fuzzy model based control systems that have been proposed in the literature. It is also shown in this thesis that the proposed control algorithm can be easily extended to address the requirements of time-varying processes and processes requiring compensation for disturbance inputs and dead times. The application of the control system to multivariable processes and the ability to incorporate explicit constraints in the optimisation process are also demonstrated.
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Al-Alawi, Ahmed. "Dynamic modelling and performance monitoring of chemical processes". Thesis, University of Newcastle Upon Tyne, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.427331.
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Wheeler, J. "Physical and chemical processes in ductile shear zones". Thesis, University of Leeds, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.375358.
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Davison, Suzanne Elizabeth Lisa Kimm. "Chemical processes accompanying the autoxidation of paint films". Thesis, Royal Holloway, University of London, 1989. http://repository.royalholloway.ac.uk/items/ccb898a1-2fd5-4866-b895-b07031332ef3/1/.
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Film forming systems were prepared from allyloxy compounds, in conjunction with polyacrylates, together with a redox promoter and solvent. The allyloxy compounds used were based upon two broad types namely (1) tris-(N-allyloxymethyl-N-methoxymethyl) melamine and (2) tri (2-(3' propenoxymethyl)ethylene) glycol 1-ethyl ether. The structure of the crosslinked matrix appeared to consist mainly of polymerised allyloxy compound. If the polyacrylate, (derived from butyl acrylate, methyl methacrylate and methacrylic acid), used in the film forming system consisted of non-derivatised carboxyl groups along the chain, then no chemical interaction seemed to occur between the drying system and polymer. The polymer merely became entrapped in the crosslinking matrix of the allyloxy compound. However, if some of the free carboxyl groups were reacted with allyl glycidyl ether, so that some pendant allyloxy groups were present, then the rate of drying was marginally increased and more polymer was incorporated in the dried film than with the unmodified polyacrylate. These conclusions were based upon a combination of results using G.P.C., FTIR and radiolabelling. The 'yellowing' of alkyd films, particularly in the dark and at elevated temperatures was investigated by attempting the characterisation of the yellow productsderived from trans-2-hexenal. This compound has been identified as one of the autoxidative degradation products of both the methyl esters of linoleic and linolenic acids and alkyds derived therefrom. Analysis by gc-ms, with El and NH3-CI and accurate mass measurement of the derivatised alkali soluble products derived from trans-2-hexenal, which had yellowed in the dark at 70°C, gave structures which showed epoxide formation with possible rearrangement to carbonyl compounds. 2-Propenal was identified as a by-product of the autoxidative degradation of the allyloxy drying systems. Similar analysis by gc-ms of 'yellowed' 2-propenal gave structures of the form H(CH=CH-CHOH)- CH=CH-CHO. It is postulated that with sufficiently large n and oxidation of the secondary alcohol function that compounds would have a chromophore in the yellow region of the spectrum.
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Chen, Wei-Chen Kuppermann Aron Marcus R. A. "Isotope effects in chemical processes of atmospheric interest /". Diss., Pasadena, Calif. : California Institute of Technology, 2009. http://resolver.caltech.edu/CaltechETD:etd-01222009-173227.
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