Dissertations / Theses on the topic 'NO and SO2 elimination'
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Salem, Ibtissam. "Elimination des NOx issus de sources fixes : réduction par les hydrocarbures en C3 en présence de SO2." Poitiers, 2005. http://www.theses.fr/2005POIT2275.
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Ce travail a consisté à étudier la réduction des NOx par les hydrocarbures en C3 afin d'examiner l'influence du SO2 sur des catalyseurs à base de métaux nobles dans le domaine de température 200- 400°C en présence de CO2, H2O et en excès d'oxygène. L'étude en fonction de la richesse du milieu montre que la conversion des NOx est totale à la stœchiométrie en absence de SO2 et que le catalyseur à base de Pt/ZrAl est le plus résistant au soufre. Les performances de divers métaux (Pt, Pd, Rh, Ag, Ir, Sn) supportés sur différents oxydes (Al, K-Al, Ce-Al, Ti-Al, Zr-Al, Ce-Zr, Si, C) en réduction des NOx par le propène (1000ppm) ont montré que le catalyseur Pt/ZrAl est le plus actif. La pré-sulfatation des catalyseurs augmente généralement leur activité en présence de SO2 et diminue la sélectivité en N2O. Enfin une disparition de NO a été observée en présence de propane et absence de ce réducteur. Ceci est lié à la formation d'acide nitrique via la formation de NO2 et non à la réduction des NOxIn the present work the NOx reduction with C3 hydrocarbons has been examined. The objective is to study the influence of SO2 on metal based catalysts with an oxygen excess in the presence of CO2 and H2O, in a temperature range from 200 to 400 °C. The NOx are totally converted under stoechiometric conditions in the absence of sulfur dioxide and the most sulfur resistant catalyst is Pt/ZrAl. A series of different metals (Pt, Pd, Rh, Ag, Ir, Sn ) supported on several oxides (Al, , K-Al, Ce-Al, Ti-Al, Zr-Al, Ce-Zr, Si, C) were tested for NOx reduction with 1000 ppm propylene and the Pt/ZrAl was found to be the most active catalyst. The sulfation of the catalysts, generally leads to an increase of their activity in the presence of SO2, and conversely to a decrease of the N2O selectivity. Finally, the NO consumption has been observed in both the presence and the absence of propane. This phenomenon has been associated with the nitric acid formation via NO oxidation and not with NOx reduction
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Chippaux, Jean-Philippe. "La dracunculose en savane arboree au benin. Etudes systematique, epidemiologique et moyens a mettre en oeuvre pour son elimination." Paris 6, 1991. http://www.theses.fr/1991PA066443.
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Un passage hebdomadaire a ete effectue entre 1985 et 1989, dans quatre villages du centre benin. Il a permis d'etudier la transmission de dracunculus medinensis et d'evaluer les strategies de lutte proposees contre cette helminthiase dermique. Dans les mares villageoises, une transmission prolongee s'effectue en saison seche avec thermocyclops oblongatus et t. Prolatus comme hotes intermediaires. Dans les retenues de barrage, la transmission, assuree en saison seche par t. Emini, est breve. Aucun parametre physico-chimique, en dehors de la temperature, n'a presente de correlation avec les densites d'hotes intermediaires. Toutefois, les milieux aquatiques confines se revelent plus favorables a la transmission. La densite minimale de cyclopides necessaire pour assurer une transmission stable peut etre evaluee a 1 cyclopide par litre. Il ne semble pas qu'il y ait de relation entre la densite de cyclopides et l'incidence. 720 cas de draconculose ont ete examines entre 1985 et 1989. 90% des emergences se situent au niveau des membres inferieurs. Des complications ont ete observees dans 57,5% des cas entrainant une incapacite chez 44,7% des malades. La perte de temps de travail correspond a 7,5% du temps actif. L'entraide villageoise permet de maintenir le niveau des revenus. L'absenteisme scolaire, lie a l'incapacite ou au remplacement des adultes, est eleve. Le cout de la draconculose a ete evalue a 15% des revenus annuels. Les antihelminthiques sont inefficaces. Le temephos est actuellement le seul cyclopicide utilisable pour la lutte antivectorielle. L'approvisionnement en eau potable est essentiel. Toute strategie de lutte doit etre associee a une education pour la sante
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Yan, Yige. "TiO2 photocatalysts prepared via a sol-gel route assisted by P- and F- containing additives : applications to the degradation of MEK and to the elimination of bacteria on surfaces." Thesis, Strasbourg, 2016. http://www.theses.fr/2016STRAF063/document.
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L'objectif de ce travail est de synthétiser des nanomatériaux de TiO2 pour la dégradation des COV et pour l'élimination des bactéries en surface. Tout d'abord, basé sur une synthèse des matériaux de TiO2 avec la présence d’un liquide ionique BmimPF6 par une voie sol-gel modifiée, les rôles de deux éléments constitutifs de BmimPF6 (P et F) ont été étudiés en faisant remplacer BmimPF6 par des additives contenant P et F. Par rapport à la référence P25 et aux matériaux de TiO2 synthétisés sans additif, le TiO2 synthétisé en présence de P a déjà montré une meilleure cristallinité en phase anatase avant la calcination, et une surface spécifique élevée et une petite taille moyenne des cristaux étaient maintenus même après calcination. Ces propriétés étaient similaires aux échantillons TiO2 synthétisés en présence de BmimPF6; Tandis que les cristaux de TiO2 en présence de F ont montré une forme anisotrope pendant le murissement de la synthèse. Les évaluations de l'activité photocatalytique des photocatalyseurs ont ensuite été réalisées. Par rapport au TiO2 synthétisé sans additif et au TiO2 P25, les matériaux de TiO2 à faible teneur en P et F ("PANaF") ont présenté une activité plus élevée sous irradiation UVA à la dégradation d'un COV modèle, Méthyléthylcétone (MEK) en phase gazeuse. Le même matériau a également montré une activité anti-bactérienne en surface plus élevée sous UVA contre plusieurs souches de différentes espèces bactériennes dans liquide par rapport à celles de P25. Une corrélation entre la performance photocatalytique élevée et les propriétés des matériaux pour TiO2 "PANaF" a été finalement proposée. Les influences de la présence de PO43- en bulk ou en surface de TiO2, de la concentration d’O2 dissous dans le milieu et de la topologie de surface des photocatalyseurs sur l'activité photocatalytique éteint également sujets de discussion. Le produit "PANaF" présente un intérêt pour l'élaboration industrielle à cause des réactifs pas cher et son performance élevéeThe objective of this work consists in synthesizing TiO2 nanomaterials designed for the degradation of VOCs and for the elimination of bacteria on surface. Firstly, based on a synthesis of a BmimPF6-ionic liquid-derived TiO2 material through a modified sol-gel route, the roles of two constituent elements of BmimPF6 (P and F) have been investigated by replacing BmimPF6 with P- and F- contained additives. Comparing to the reference P25 and additive-free-derived TiO2 materials, P-derived TiO2 showed already well crystallized anatase phase before calcination and a high surface area along with a small mean crystal size even after calcinations. Those properties were similar to that synthesized with the presence of BmimPF6; while F-derived TiO2 crystals showed anisotropic shape during the aging step of the synthesis. Evaluation of the photocatalytic activity of the photocatalysts has been performed then. Compared to additive-free derived TiO2 and the TiO2 P25, P- and F- derived TiO2 materials with low P and F content (“PANaF”) showed higher activity under UVA in terms of gas-phase degradation of a model VOC, Methl Ethyl Ketone (MEK). The same material also showed higher surface anti-bacterial activity under UVA in liquid against several strains of different bacterial species over that of P25. A correlation between the high photocatalytic performances with the material properties for “PANaF” TiO2 materials was finally proposed. The influences of the presence of bulk or surface PO43-, dissolved O2 concentration and surface topology on photocatalytic activity were also discussed. The cheap replacement additives used and the resulted high activity of “PANaF” TiO2 nanomaterials presents interest for industrial elaboration
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Ould, Mohamdi El Khalil. "Elimination réduite." Université Louis Pasteur (Strasbourg) (1971-2008), 1988. http://www.theses.fr/1988STR13182.
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La condition pour que n polynomes homogenes en n variables, ayant un zero commun de multiplicites donnees, en admettent un autre est essentiellement l'annulation d'un polynome en leurs coefficients, appele "resultant reduit". L'objet de cette these est d'en faire une etude moderne et d'en etablir les principales proprietes
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Ould, Mohamdi El Khalil. "Elimination réduite." Grenoble 2 : ANRT, 1988. http://catalogue.bnf.fr/ark:/12148/cb376172344.
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Anton, Peter, and André Laschewsky. "Polysoaps via alternating olefin/SO2 copolymers." Universität Potsdam, 1991. http://opus.kobv.de/ubp/volltexte/2008/1721/.
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Contents:
Introduction
Results and discussion
- Monomers studied
- Monomer properties
- Polymerization, copolymer composition and general properties
- Polymer properties in aqueous solution
Conclusion
Experimental part
- Materials
- Copolymerization with S02 (typical procedure)
- Methods
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Souza, Ana Carolina Bello de. "Estudo te?rico das rea??es de SN2 em fase gasosa: RCI+OH??ROH+CI? (R = Metil, Etil, n-Propil, i-Propil, n- Butil, s-Butil e t-Butil)." Universidade Federal Rural do Rio de Janeiro, 2012. https://tede.ufrrj.br/jspui/handle/jspui/1547.
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Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES
In this work, the theoretical study of the gas-phase bimolecular nucleophilic substitution reaction, CH3Cl + OH- CH3OH + Cl-, is introduced, aiming the description of the potential energy surface, the calculation of rate constants and the investigation of the effect of increasing the side chain (changing the CH3 radical in the reaction cited above by the radicals ethyl, n-propyl, i-propyl, n-butyl, s-butyl e t-butyl). The theoretical calculations have been first performed at the MP2/6-31+G(d) level for the geometry optimizations and vibrational frequencies calculations. Single point calculations at the CCSD(T)/6-31+G(d) level have also been performed in order to improve the total energies for the stationary points. However, the relative energies of these stationary points at both MP2 and CCSD(T) level shown close results, so that the single point calculations at the CCSD(T) level have not been proved strictly necessary and have therefore not been performed for all the points along the potential energy surface. The minimum energy path has been described by the intrinsic reaction coordinate method, calculated at the MP2/6-31+G(d) by performing sequential geometry optimizations starting from the saddle point. The calculated enthalpy difference at 298K for the reaction has been determined as -49.5 kcal/mol, in good agreement with the literature value: -50.5 kcal/mol. The calculated rate constant has been obtained as 1.41 x 10-9 cm3.molecule-1.s-1, at 298,15K, in excellent agreement with the experimental data: 1.3 ? 1.6 x 10-9 cm3.molecule-1.s-1.Moreover, the rate constants show non-Arrhenius behavior, decreasing as the temperature increases, which is consistent with the experimental expectation. In this way, the performance of the variational transition state theory for this reaction can be considered satisfactory. By increasing the side chain of the reactant, other reaction channels have been observed: the bimolecular elimination E2 channel and the attack of the nucleophile from the same plane of the exit group (the front-SN2).For these reactions of the alkyl chlorides on n carbon atoms (1 < n ? 4), the B3LYP/6-31+G(d,p) level has been adopted for geometry optimizations and vibrational frequencies. Then, single point calculations at the CCSD(T)/6-31+G(d,p)//B3LYP/6- 31+G(d,p) level have been performed. A comparison of the reaction channels, back- SN2 and E2, shows that the E2 channel is kinetically favored, whereas the SN2 products are thermodynamically more stable. As expected, high values for the potential height have been observed for the front-SN2, being these channels disfavored in all cases. In general, the energy of the saddle points in respect to the isolated reactants slightly depend upon the size of the side chain.
Este trabalho trata do estudo te?rico das rea??es de substitui??o nucleof?lica de segunda ordem, CH3Cl + OH- CH3OH + Cl-, em fase gasosa, visando estudar a superf?cie de energia potencial, obter as constantes de velocidade e ainda verificando o efeito do aumento da cadeia lateral (trocando o radical CH3 na rea??o descrita acima por radicais etil, n-propil, i-propil, n-butil, s-butil e t-butil). Primeiramente, c?lculos te?ricos para otimiza??es de geometria e frequ?ncia foram realizados em n?vel MP2/6-31+G(d) para a rea??o CH3Cl + OH- CH3OH + Cl- e, em seguida, c?lculos single-point em n?vel CCSD(T)/6-31+G(d) foram realizados para corrigir os valores da energia eletr?nica dos pontos estacion?rios obtidos no caminho de rea??o. Entretanto, os valores obtidos para as energias relativas em n?veis MP2 e CCSD(T) foram muito pr?ximos, n?o sendo estritamente necess?rio refinar,atrav?s de c?lculos single-point em n?vel CCSD(T)/6- 31+G(d),os valores de energia de todos os pontos obtidos na superf?cie de energia potencial. O caminho de rea??o menor energia foi descrito pela coordenada de rea??o intr?nseca, calculada por otimiza??es de geometrias de uma sequ?ncia de configura??es ao redor do ponto de sela em n?vel MP2/6-31+G(d). A diferen?a de entalpia a 298K calculada para a rea??o foi de -49,5 kcal/mol, em bom acordo com o dado da literatura, -50,5 kcal/mol. A constante de velocidade da rea??o obtida foi de 1,41 x 10-9 cm3.mol?cula-1.s-1, a 298,15K, em excelente acordo com o dado experimental: 1,3 ? 1,6 x 10-9 cm3.mol?cula-1.s-1. Al?m disso, as constantes de velocidade globais apresentam comportamento n?o-Arrhenius, diminuindo conforme a temperatura aumenta, em um perfil consistente com a observa??o experimental. Dessa forma, a aplica??o da teoria de estado de transi??o se mostra satisfat?ria para essa rea??o. A partir do aumento da cadeia lateral, outros canais de rea??o foram observados, em prov?vel competi??o ? substitui??o nucleof?lica de ordem 2: a elimina??o de segunda ordem, E2. O ataque do nucle?filo pela frente da cadeia tamb?m foi obtido e investigado. Para as rea??es dos cloretos de alquila com cadeia lateral de n carbonos (1 < n ? 4), o n?vel B3LYP/6- 31+G(d,p) foi adotado para c?lculos de otimiza??es e frequ?ncias. Posteriormente, c?lculos em n?vel CCSD(T)/6-31+G(d,p)//B3LYP/6-31+G(d,p) foram realizados. Comparando os canais de rea??o de substitui??o nucleof?lica back e de elimina??o, o canal cineticamente favorecido foi o de elimina??o, por?m os produtos termodinamicamente mais est?veis s?o os de substitui??o nucleof?lica. Como esperado, observa-se uma barreira de potencial muito alta para as rea??es substitui??o pela frente, sendo esses canais desfavorecidos em todos os casos.Em geral, a diferen?a de energia dos pontos de sela em rela??o aos reagentes isolados mostra pequena depend?ncia com o aumento da cadeia lateral linear
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Fernández, Gómez Manuel. "Binary Redundancy Elimination." Doctoral thesis, Universitat Politècnica de Catalunya, 2005. http://hdl.handle.net/10803/5985.
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Dos de las limitaciones de rendimiento más importantes en los procesadores de hoy en día provienen de las operaciones de memoria y de las dependencias de control. Para resolver estos problemas, las memorias cache y los predictores de salto son dos alternativas hardware bien conocidas que explotan, entre otros factores, el reuso temporal de memoria y la correlación de saltos. En otras palabras, estas estructuras tratan de explotar la redundancia dinámica existente en los programas. Esta redundancia proviene parcialmente de la forma en que los programadores escriben código, pero también de limitaciones existentes en el modelo de compilación tradicional, lo cual introduce instrucciones de memoria y de salto innecesarias. Pensamos que los compiladores deberían ser muy agresivos optimizando programas, y por tanto ser capaces de eliminar una parte importante de esta redundancia. Por otro lado, las optimizaciones aplicadas en tiempo de enlace o directamente al programa ejecutable final han recibido una atención creciente en los últimos años, debido a limitaciones existentes en el modelo de compilación tradicional. Incluso aplicando sofisticados análisis y transformaciones interprocedurales, un compilador tradicional no es capaz de optimizar un programa como una entidad completa. Un problema similar aparece aplicando técnicas de compilación dirigidas por profiling: grandes proyectos se ven forzados a recompilar todos y cada uno de sus módulos para aprovechar dicha información. Por el contrario, seria más conveniente construir la aplicación completa, instrumentarla para obtener información de profiling y optimizar entonces el binario final sin recompilar ni un solo fichero fuente.
En esta tesis presentamos nuevas técnicas de compilación dirigidas por profiling para eliminar la redundancia encontrada en programas ejecutables a nivel binario (esto es, redundancia binaria), incluso aunque estos programas hayan sido compilados agresivamente con un novísimo compilador comercial. Nuestras técnicas de eliminación de redundancia están diseñadas para eliminar operaciones de memoria y de salto redundantes, que son las más importantes para mitigar los problemas de rendimiento que hemos mencionado. Estas propuestas están basadas en técnicas de eliminación de redundancia parcial sensibles al camino de ejecución. Los resultados muestran que aplicando nuestras optimizaciones, somos capaces de alcanzar una reducción del 14% en el tiempo de ejecución de nuestro conjunto de programas.
En este trabajo también revisamos el problemas del análisis de alias en programas ejecutables, identificando el por qué la desambiguación de memoria es uno de los puntos débiles en la modificación de código objeto. Proponemos varios análisis para ser aplicados en el contexto de optimizadores binarios. Primero un análisis de alias estricto para descubrir dependencias de memoria sensibles al camino de ejecución, el cual es usado en nuestras optimizaciones para la eliminación de redundancias de memoria.
Seguidamente, dos análisis especulativos de posibles alias para detección de independencias de memoria. Estos análisis están basados en introducir información especulativa en tiempo de análisis, lo que incrementa la precisión en partes importantes de código manteniendo el análisis eficiente. Los resultados muestran que nuestras propuestas son altamente útiles para incrementar la desambiguación de memoria de código binario, lo que se traduce en oportunidades para aplicar optimizaciones.
Todos nuestros algoritmos, tanto de análisis como de optimización, han sido implementados en un optimizador binario, enfatizando los problemas más relevantes en la aplicaciones de nuestros algoritmos en código ejecutable, sin la ayuda de gran parte de la información de alto nivel presente en compiladores tradicionales.
Two of the most important performance limiters in today's processor families comes from solving the memory wall and handling control dependencies. In order to address these issues, cache memories and branch predictors are well-known hardware proposals that take advantage of, among other things, exploiting both temporal memory reuse and branch correlation. In other words, they try to exploit the dynamic redundancy existing in programs. This redundancy comes partly from the way that programmers write source code, but also from limitations in the compilation model of traditional compilers, which introduces unnecessary memory and conditional branch instructions. We believe that today's optimizing compilers should be very aggressive in optimizing programs, and then they should be expected to optimize a significant part of this redundancy away.
On the other hand, optimizations performed at link-time or directly applied to final program executables have received increased attention in recent years, due to limitations in the traditional compilation model. First, even though performing sophisticated interprocedural analyses and transformations, traditional compilers do not have the opportunity to optimize the program as a whole. A similar problem arises when applying profile-directe compilation techniques: large projects will be forced to re-build every source file to take advantage of profile information. By contrast, it would be more convenient to build the full application, instrument it to obtain profile data and then re-optimize the final binary without recompiling a single source file.
In this thesis we present new profile-guided compiler optimizations for eliminating the redundancy encountered on executable programs at binary level (i.e.: binary redundancy), even though these programs have been compiled with full optimizations using a state-ofthe- art commercial compiler. In particular, our Binary Redundancy Elimination (BRE) techniques are targeted at eliminating both redundant memory operations and redundant conditional branches, which are the most important ones for addressing the performance issues that we mentioned above in today's microprocessors. These new proposals are mainly based on Partial Redundancy Elimination (PRE) techniques for eliminating partial redundancies in a path-sensitive fashion. Our results show that, by applying our optimizations, we are able to achieve a 14% execution time reduction in our benchmark suite.
In this work we also review the problem of alias analysis at the executable program level, identifying why memory disambiguation is one of the weak points of object code modification. We then propose several alias analyses to be applied in the context of linktime or executable code optimizers. First, we present a must-alias analysis to recognize memory dependencies in a path- sensitive fashion, which is used in our optimization for eliminating redundant memory operations. Next, we propose two speculative may-alias data-flow algorithms to recognize memory independencies. These may-alias analyses are based on introducing unsafe speculation at analysis time, which increases alias precision on important portions of code while keeping the analysis reasonably cost-efficient. Our results show that our analyses prove to be very useful for increasing memory disambiguation accuracy of binary code, which turns out into opportunities for applying optimizations.
All our algorithms, both for the analyses and the optimizations, have been implemented within a binary optimizer, which overcomes most of the existing limitations of traditional source-code compilers. Therefore, our work also points out the most relevant issues of applying our algorithms at the executable code level, since most of the high-level information available in traditional compilers is lost.
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Seidler, Torsten. "Minderung rohmaterialbedingter SO2-Emissionen in der Zementindustrie /." Düsseldorf : Verl. Bau und Technik, 2006. http://www.agi-imc.de/intelligentSEARCH.nsf/alldocs/6884DFF6B3D69539C12571E0003774AD/$File/000000016401889.PDF?OpenElement.
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Zhang, Wensheng. "SO2/O2 as an oxidant in hydrometallurgy." Thesis, Zhang, Wensheng (2000) SO2/O2 as an oxidant in hydrometallurgy. PhD thesis, Murdoch University, 2000. https://researchrepository.murdoch.edu.au/id/eprint/458/.
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Zhang, Wensheng. "SO2/O2 as an oxidant in hydrometallurgy." Murdoch University, 2000. http://wwwlib.murdoch.edu.au/adt/browse/view/adt-MU20080115.141151.
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Cai, Qiong Computer Science & Engineering Faculty of Engineering UNSW. "Profile-guided redundancy elimination." Awarded by:University of New South Wales. School of Computer Science and Engineering, 2006. http://handle.unsw.edu.au/1959.4/25156.
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Program optimizations analyze and transform the programs such that better performance results can be achieved. Classical optimizations mainly use the static properties of the programs to analyze program code and make sure that the optimizations work for every possible combination of the program and the input data. This approach is conservative in those cases when the programs show the same runtime behaviors for most of their execution time. On the other hand, profile-guided optimizations use runtime profiling information to discover the aforementioned common behaviors of the programs and explore more optimization opportunities, which are missed in the classical, non-profile-guided optimizations. Redundancy elimination is one of the most powerful optimizations in compilers. In this thesis, a new partial redundancy elimination (PRE) algorithm and a partial dead code elimination algorithm (PDE) are proposed for a profile-guided redundancy elimination framework. During the design and implementation of the algorithms, we address three critical issues: optimality, feasibility and profitability. First, we prove that both our speculative PRE algorithm and our region-based PDE algorithm are optimal for given edge profiling information. The total number of dynamic occurrences of redundant expressions or dead codes cannot be further eliminated by any other code motion. Moreover, our speculative PRE algorithm is lifetime optimal, which means that the lifetimes of new introduced temporary variables are minimized. Second, we show that both algorithms are practical and can be efficiently implemented in production compilers. For SPEC CPU2000 benchmarks, the average compilation overhead for our PRE algorithm is 3%, and the average overhead for our PDE algorithm is less than 2%. Moreover, edge profiling rather than expensive path profiling is sufficient to guarantee the optimality of the algorithms. Finally, we demonstrate that the proposed profile-guided redundancy elimination techniques can provide speedups on real machines by conducting a thorough performance evaluation. To the best of our knowledge, this is the first performance evaluation of the profile-guided redundancy elimination techniques on real machines.
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Herold, F. W., and J. A. Kaiser. "ELIMINATION OF SIDELOBE RESPONSE." International Foundation for Telemetering, 1998. http://hdl.handle.net/10150/607377.
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International Telemetering Conference Proceedings / October 26-29, 1998 / Town & Country Resort Hotel and Convention Center, San Diego, CaliforniaConventional phased arrays nominally sum the signals received by the elements prior to detection. By multiplying rather than summing signals received from pairs of elements, i.e., interferometer pairs, a set of Spatial Frequencies (SFs) is obtained. Obtaining the SFs requires employment of a multiple local oscillator technique. When summed, these spatial frequencies produce a single lobed (voltage) radiation pattern which, when passed through a biased detector, removes all sidelobes from the response at a small loss of desired signal power.
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Ramírez, Torres Dulce María. "Interfase líquido-vapor del óxido de azufre (SO2)." Tesis de Licenciatura, Universidad Autónoma del Estado de México, 2017. http://hdl.handle.net/20.500.11799/68451.
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Se llevaron a cabo simulaciones de dinámica molecular a través del software libre Gromacs. Se calculó la constante dieléctrica del dioxido de azufre en fase líquida. En el equilibrio líquido-vapor se calculó la tension superficial, la presion de vapor y las densidades del equlibrio. El modelo de SO2 que se utilizó para obtener nuestros resultados fue un modelo modificado del propuesto por Ketko y colaboradores. Dicho modelo consta de tres sitios de interacción donde las distancias atomo- atomo se mantuvieron fijas, de manera que las interacciones intermoleculares fueron modeladas por el potencial de Lennard-Jones y de Coulomb y las interacciones intramoleculares fueron modeladas con un potencial armonico en el angulo.El dioxido de azufre es una molécula compuesta por un atomo de azufre y dos atomos de oxígeno con formula molecular SO2 es un gas incoloro con un olor irritante característico que generalmente se percibe entre 0.3-1.4 ppm (partes por millón). Esta molécula no es inflamable tampoco explosivo y es relativamente estable. Su densidad es más del doble que la del aire ambiental, y es altamente soluble en agua formando disoluciones acidas. En contacto con membranas húmedas el SO2 forma acido sulfúrico H2 SO4 , que es responsable de fuertes irritaciones en los ojos, membranas mucosas y piel.
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Ribeiro, Catarina da Silva Espada. "Redimensionamento de uma torre de absorção de SO2." Master's thesis, Universidade de Aveiro, 2013. http://hdl.handle.net/10773/11644.
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Mestrado em Engenharia QuímicaEste trabalho consiste no estudo da Torre de Absorção de SO2 da empresa Soporcel, a qual se encontra com um funcionamento irregular. Com este estudo pretende-se que a coluna passe a funcionar corretamente, garantindo que as emissões deste soluto se encontram dentro dos limites exigidos pela legislação ambiental em vigor. A análise preliminar do processo foi fundamentada pelos dados facultados pela empresa, tendo-se verificado que apresenta problemas ao nível do humedecimento, os quais justificam o mau funcionamento desta. Além do estudo da torre real, o trabalho apresenta sugestões para superar o problema aproveitando o mesmo equipamento, assim como projeta uma nova torre de absorção.
This work comprises a study of a SO2 absorption tower that has not been working properly at Soporcel factory. The study aims at correcting the tower irregular operation and assuring that the solute emissions are within the limits imposed by current environmental laws. The preliminary analysis of the process based on data from Soporcel revealed problems at wetting level, which can justify the inefficient separation detected on the equipment. In addition to the evaluation of the existing tower, this work presents suggestions to overcome the current problems whether by maintaining the same equipment structure or through a project of a new tower.
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Gonçalves, Catarina Salvador. "Remoção de SO2 por cinzas volantes de biomassa." Master's thesis, Universidade de Aveiro, 2014. http://hdl.handle.net/10773/15584.
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Mestrado em Engenharia do AmbienteOs óxidos de enxofre (SOx) são conhecidos por constituírem uma importante fonte de poluição atmosférica, sendo precursores da formação de nevoeiro ácido e chuvas ácidas. Esta categoria de poluentes afeta também a saúde humana, estando associada ao aumento de doenças respiratórias, de morbidez e de mortalidade. Por estes motivos, a União Europeia e muitos países têm aprovado regulamentação cada vez mais restrita para as emissões atmosféricas dos referidos compostos. Dependendo do tipo de combustível e de instalação de combustão, o controlo das emissões de SOx pode ser feito numa das três etapas: na pré-combustão, na combustão (chama) e na pós-combustão. Sendo que a maioria das tecnologias de controlo destas emissões têm aplicação na etapa pós-combustão, i.e. no tratamento de gases de combustão. O método mais usado para remover SOx dos gases de combustão é através da sua adsorção por óxidos metálicos. Este tipo de processo de dessulfurização possui duas vias: a seca e a húmida. Apesar do relativo baixo custo de operação e da elevada eficiência, qualquer uma destas vias convencionais apresenta desvantagens (elevados consumo de água com o consequente elevado volume de efluentes líquidos a tratar, elevada produção de gesso como subproduto, etc.). Este facto tem motivado a comunidade científica, desde há quase duas décadas, a investigar métodos alternativos que ultrapassem as desvantagens dos convencionais. Neste contexto, este trabalho surge com o principal objetivo de desenvolver sorventes, à base de cinzas volantes da queima de biomassa, com vista à remoção de SO2 de efluentes gasosos. Deste modo, valoriza-se também um resíduo sólido com crescente produção em Portugal. Na componente experimental do trabalho foram usados duas variedades de cinzas volantes de biomassa (“B” e “C”) para a preparação de sorventes com água e várias razões mássicas de hidróxido de cálcio. De todos os sorventes foram preparados grânulos tendo em vista uma posterior aplicação industrial e facilidade de manuseamento. Os sorventes foram caracterizados em termos do teor em metais alcalino e alcalino-terrosos (sendo o metal mais abundante o cálcio), valor neutralizante, pH e composição mineralógica por difração de raios-X (DRX). Os sorventes em pó e em grânulos foram testados em ensaios de dessulfurização, num reator contínuo de leito fixo, de um efluente gasoso sintético, à temperatura ambiente com uma mistura de 1000ppm SO2 e árgon. Destes ensaios selecionou-se o sorvente que apresentou maior capacidade de remoção de SO2, um à base de cinza “C”. Com este sorvente foram realizados mais ensaios com vista a avaliar o efeito da temperatura (150º C, 220º C e 300º C) e da concentração de SO2 (500ppm e 1000ppm) na eficiência de remoção do SO2. Conclui-se que a temperatura tem um efeito negativo dos 25º C para os 150º C (como era expectável, porque os processos de adsorção são exotérmicos); no entanto dos 150º C para os 220º C dá-se um ligeiro aumento e desta para os 300º C um aumento ainda maior, e o da concentração de SO2 é positivo, i.e. com o aumento da concentração de SO2 no gás há um favorecimento da cinética de adsorção.Este sorvente com melhor desempenho na remoção de SO2 foi analisado por DRX antes e depois de ter sido testado no reator de leito fixo, onde os elementos quartzo (syn-SiO2), calcite (syn-CaCO3) e portlandite (syn-Ca(OH)2) se enalteceram por estarem presentes em quantidades superiores nas 2 amostras. Também se determinou o pH e valor neutralizante de todos os sorventes depois dos ensaios de dessulfurização, registando-se uma diminuição de ambos os parâmetros relativamente aos valores iniciais. Porém, qualquer um destes parâmetros revelou-se inadequado para a monitorização (de forma indireta) do grau de dessulfurização conseguido num ensaio.
Sulfur oxides (SOx) are known to constitute a major source of air pollution, acid precursors to the formation of fog and acid rain. This category of pollutants also affects human health and is associated with increases in respiratory diseases, morbidity and mortality. For these reasons, the European Union and many countries have adopted regulations increasingly restricted for air emissions of these compounds. Depending on the type of fuel and combustion plant, the control of SOx emissions can be done in one of three stages: pre-combustion, combustion (flame) and post-combustion. Most of these emissions control technologies have application in the post-combustion step, corresponding to the the flue gases treatment. The method most commonly used to remove SOx from the flue gas is through adsorption by metallic oxides. This type of desulfurization process has two routes: the dry and the wet. Despite of the relatively low cost of operation and high efficiency, any of these conventional routes have disadvantages (high water consumption with consequent high volume of wastewater to be treated, high production of gypsum as a byproduct, etc.). This has motivated the scientific community, for almost two decades, to investigate alternative methods to overcome the drawbacks of conventional. In this context, this work arises with the main goal to develop sorbents, based on fly ash from biomass combustion, for the removal of SO2 from gaseous effluents. By this wayone also recover a solid waste with growing production in Portugal. For the experimental work component it was used two types of fly ash from biomass ("B" and "C") for the preparation of sorbents in water and various weight ratios of calcium hydroxide. It was prepared granules from all sorbent with foreseeing a later industrial application and ease of handling. The sorbents were characterized in terms of the content of alkali and terrous-alkalin metals (being the calcium the most abundant metal) neutralizing value, pH and mineral composition by X-ray diffraction (XRD). The sorbent powder and granules were tested in desulfurization essays in a continuous fixed bed reactor, of a synthetic flue gas at room temperature with a mixture of 1000 ppm of SO2 and argon. From these trials was selected the sorbent that showed the highest SO2 removal performance, a "C" fly ash based. With this sorbent it was carried out more essays in order to assess the effect of temperature (150° C, 220° C and 300° C) and SO2 concentration (500ppm and 1000ppm) on the SO2 removal efficiency. It was conclude that temperature has a negative effect from 25° C to 150° C (as expected, because the adsorption processes are exothermic); however from 150º C to 220º C it happens a slight increase and to 300º C a bigger increase, and the SO2 concentration is positive, this is with increasing concentration of SO2 in the gas there is a favoring favoring kinetic adsorption. This sorbent with better performance in SO2 removal was analyzed by XRD before and after being tested in a fixed bed reactor, where the elements quartz (syn-SiO2), calcite (syn-CaCO3) and portlandite (syn-Ca(OH)2) were highlighted for being present in higher amounts in the two samples. It was also determined the pH and neutralizing value of all sorbents after the desulfurization tests, registering a decrease of both parameters compared to the initial values. However, any of these parameters were proved inadequate for monitoring (indirectly) the degree of desulfurization achieved in a test.
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Tesař, Jan. "Snížení emisí SO2 ve spalinách z fluidního kotle." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2016. http://www.nusl.cz/ntk/nusl-241676.
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Aim of this thesis is to design a technology of a flue gas desulphurization of fluidized bed boiler. Currently, the state of technology is not able to provide flue gas desulphurisation to required level. For this reason it is necessary to build additional device for the desulphurisation. Theoretical part of the thesis deals with the emission limits of sulphur dioxide, available methods of desulphurization and sorbents suitable for the desulfurization. In practical part conditioned dry sorption method is chosen for the specified source, technological and structural design for suggested desulphurization technology including design of all device is proposed. The thesis also includes a technology design and a 3D model.
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Wernhard, Christoph. "Automated deduction for projection elimination /." Heidelberg : AKA, 2009. http://opac.nebis.ch/cgi-bin/showAbstract.pl?u20=9783898383240.
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Sankar, Arvind 1976. "Smoothed analysis of Gaussian elimination." Thesis, Massachusetts Institute of Technology, 2004. http://hdl.handle.net/1721.1/28311.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mathematics, 2004.Includes bibliographical references (p. 59-60).
We present a smoothed analysis of Gaussian elimination, both with partial pivoting and without pivoting. Let A be any matrix and let A be a slight random perturbation of A. We prove that it is unlikely that A has large condition number. Using this result, we prove it is unlikely that A has large growth factor under Gaussian elimination without pivoting. By combining these results, we bound the smoothed precision needed to perform Gaussian elimination without pivoting. Our results improve the average-case analysis of Gaussian elimination without pivoting performed by Yeung and Chan (SIAM J. Matrix Anal. Appl., 1997). We then extend the result on the growth factor to the case of partial pivoting, and present the first analysis of partial pivoting that gives a sub-exponential bound on the growth factor. In particular, we show that if the random perturbation is Gaussian with variance [sigma]², then the growth factor is bounded by (n/[sigma])[to the power of] (o log n) with very high probability.
by Arvind Sankar.
Ph.D.
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Budd, Chris. "Data Protection and Data Elimination." International Foundation for Telemetering, 2015. http://hdl.handle.net/10150/596395.
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ITC/USA 2015 Conference Proceedings / The Fifty-First Annual International Telemetering Conference and Technical Exhibition / October 26-29, 2015 / Bally's Hotel & Convention Center, Las Vegas, NVData security is becoming increasingly important in all areas of storage. The news services frequently have stories about lost or stolen storage devices and the panic it causes. Data security in an SSD usually involves two components: data protection and data elimination. Data protection includes passwords to protect against unauthorized access and encryption to protect against recovering data from the flash chips. Data elimination includes erasing the encryption key and erasing the flash. Telemetry applications frequently add requirements such as write protection, external erase triggers, and overwriting the flash after the erase. This presentation will review these data security features.
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Arnaudiès, Jean-Marie. "Elimination et theorie de galois." Toulouse 3, 1989. http://www.theses.fr/1989TOU30090.
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La these comporte une introduction et trois chapitres. L'introduction est consacree aux resultants ordinaires, et contient une preuve effective du theoreme des zeros de hilbert, par elimination successive a la kronecker. Au premier chapitre, on expose la theorie de hurwitz des ideaux d'inertie, puis a partir de la notion de mineur de macaulay, on donne une version affinee du theoreme principal de l'elimination; enfin on etudie en detail les ideaux d'inergie generiques. Au second chapitre, on definit le resultant de polynomes a plusieurs variables; on en donne des proprietes arithmetiques et algebriques, notamment la complete irreductivilite. Au point general de l'hypersurface resultant, on construit le zero commun; on en deduit des chaines maximales d'ideaux premiers aboutissant a l'ideal d'elimination generique. On decrit un algorithme potentiellement effectif pour analyser les composantes irreductibles, leur dimension et leur degre, d'un ensemble algebrique ferme affine sur un corps algebriquement clos. Au troisieme chapitre, on definit une extension algebrique finie associee au theoreme de bezout generique sur les ensembles finis de points obtenus par intersection d'hypersurfaces projectives dans un espace projectif de dimension finie. Dans cette extension, on calcule la norme et le noyau de la trace, ce qui conduit a la formule de poisson-perron et a la formule d'euler-jacobi a plusieurs variables. On exprime completement la trace a l'aide de mineurs a macaulay lors les hypersurfaces sont d'egal degre
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Vizcaíno, Pedro Francisco Valencia. "Some uses of cut elimination." Thesis, University of Leeds, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.713880.
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This thesis is mainly about Proof Theory. It can be thought of as Proof Theory in the sense of Hilbert, Gentzen, Schutte, Buchholz, Rathjen, and in general what could be called the German school, but it is also influenced by many other branches, of which the bibliography might give an idea. Intuitionism and other philosophical approaches to mathematics are also an important part of what is studied, but the Leitmotif of this thesis is Cut Elimination. The first part of the thesis is concerned with countable coded ω-models of Bar Induction. In this part we work from a reverse mathematics point of view. A study for an ordinal analysis of the theory of Bar Induction (BI) is carried out, and the equivalence between the statement that every set is contained in an co-model of this theory (BI) and the well-ordering principle VX[W0(3E) WO(6x)] which says that if X is a well-ordering, then so is its Bachmann-Howard relativisation, is proven. This is a new result as far as we know, and, we hope, an important one. In the second part of the thesis we shift our viewpoint and consider intuitionistic logic and intuitionistic geometric theories. We show that geometric derivability in classical infinitary logic implies derivability in intuitionistic infinitary logic. Again, our main tool is Cut Elimination. Next, we present investigations regarding minimal logic and classical logical principles, and give a precise classification of excluded middle, ex falso, and double negation elimination. Other themes and roads are possible and, the author feels, important, but time limitations as well as a sickly and utterly daft adherence to deadlines did not permit him to carry out these studies in full. It is quite shameful.
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Yang, Shuo. "Ammonia elimination from protonated nucleobases." Diss., Columbia, Mo. : University of Missouri-Columbia, 2007. http://hdl.handle.net/10355/4977.
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Thesis (M.S.)--University of Missouri-Columbia, 2007.The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on May 27, 2009) Typescript. Includes bibliographical references.
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Liu, Yanping. "Elimination de nanoparticules d'effluents liquides." Thesis, Toulouse, INSA, 2010. http://www.theses.fr/2010ISAT0030/document.
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L'objectif de ce travail est de mettre au point une technique de séparation de nanoparticules de milieux liquides. L'étude bibliographique a montré l'étendue potentielle du problème environnemental et a dégagé une problématique industrielle immédiate, celle du rejet de nanosilice. Des tests de séparation par flottation sont menés sans additif, en présence de AlCl3, de CTAB, et en tentant de modifier la charge de surface des bulles. Ces essais ne sont pas très concluants. La flottation a pu être observée, mais uniquement quand l'additif a conduit à la création de flocs qui ont, eux, été flottés. Les résultats des tests avec additifs ont montré que l'interaction entre l'hétérocoagulation (flottation) et l'homocoagulation est très importante, conduisant à l'étude de la coagulation sous l'effet d'AlCl3, puis du CTAB. Les résultats ont mis en évidence des mécanismes de coagulation complexes, car la taille des particules joue un rôle important. Pour chaque phénomène observé, un mécanisme a été proposé, en essayant de relier les observations à la modélisation des mécanismes d'agrégation. Du point de vue du procédé de séparation, la coagulation, suivie d'une sédimentation, permet de séparer les nanoparticules de silice avec une efficacité remarquable (diminution de 99% de la turbidité)The objective of this work is to develop a technique for separating nanoparticles from liquid media. The literature has shown the potential hazard of nanoparticules and a large quantity of the nanosilica release has been entering in water resources. Tests flotation separations are carried out without additive, in the presence of AlCl3, CTAB, and trying to change the surface charge of the bubbles. These tests are not very conclusive. Flotation has been observed, but only when the additive has led to the formation of flocs which have themselves been floated. The results of tests with additives showed that the interaction between heterocoagulation (flotation) and homocoagulation is very important, leading to the study of coagulation under the effect of AlCl3 and CTAB. The results revealed complex mechanisms of coagulation, because the particle size plays an important role. For each observed phenomenon, a mechanism has been proposed, trying to link the observations to modeling mechanisms of aggregation. From the standpoint of the separation process, coagulation followed by sedimentation to separate the silica nanoparticles with remarkable efficiency (decrease of 99% of the turbidity)
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Jung, Sebastian. "Erzeugung kalter SO2-Moleküle zur Untersuchung ihrer schwellnahen Photodissoziation." [S.l.] : [s.n.], 2006. http://deposit.ddb.de/cgi-bin/dokserv?idn=981930190.
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Bär, Jaciara. "Absorção de SO2 por líquidos iônicos: efeito do ânion." Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/46/46136/tde-18082016-085659/.
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O dióxido de enxofre (SO2) é um dos principais poluentes atmosféricos e a busca por sistemas capazes de absorver, detectar e/ou quantificar este gás tem sido de grande interesse. Neste contexto, os líquidos iônicos (LI) têm demonstrado potencial aplicação em metodologias de captura e armazenamento de gases. Neste estudo, nosso maior interesse consiste em entender os principais fatores que governam as interações entre o SO2 e diferentes íons formadores de líquidos iônicos. Em particular, foi explorada a interação específica de transferência de carga entre ânions (base de Lewis) e o SO2 (ácido de Lewis). A abordagem deste trabalho foi baseada em uma investigação sistemática de LI formados pelo cátion 1-butil,3-metilimidazólio (BMI) e diferentes ânions, utilizando da espectroscopia vibracional (Raman e IR), sobretudo a espectroscopia Raman ressonante, aliada a cálculos teóricos baseados na teoria do funcional da densidade (DFT). Os resultados de espectroscopia vibracional Raman e IR, mostraram mudanças na posição e formato da banda referente ao modo de estiramento simétrico vs(SO2) dependendo do ânion e da concentração de SO2 em LI. Verificou-se deslocamentos significativos para menor número de onda em relação ao SO2 líquido puro (1145 cm-1) em menores concentrações de SO2 em LI. Na série dos haletos, Cl-, Br- e I-, quanto maior o ânion, maior o deslocamento (1138, 1133 e 1123 cm-1, respectivamente para a fração molar 0,5). No caso do tiocianato, considerado como um pseudo-haleto, a banda do modo vs(SO2) aparece em cerca de 1130 cm-1 na mesma fração molar, ou seja, em um valor intermediário entre o Br- e o I-. Esses deslocamentos observados podem ser interpretados de acordo com a interação específica de transferência de carga do ânion para o SO2. Um resultado observado que merece destaque consiste na dependência da banda Raman do modo vs(SO2) com a energia da radiação excitante, o que é denominado de dispersão Raman. Tal fenômeno pôde ser explicado utilizando o modelo de \"excitação seletiva do estado de solvatação\" em que foi possível caracterizar os diferentes estados de solvatação do SO2 em líquidos iônicos.Sulfur dioxide (SO2) is one of the main atmospheric pollutants and the search for systems capable of absorbing detect and/or quantify such gas has been of great interest. In this context, ionic liquids (IL) have shown potential application in capture methodologies and gas storage. In this study, our interest consists in the understanding of the main factors that govern the interactions between SO2 and diferents ions of ionic liquids. In particular, the charge transfer specific interaction was explored between anions (Lewis base) and SO2 (Lewis acid). The approach of this study was based on a systematic investigation of LI formed by 1-butyl cation, 3-methylimidazolium (BMI) and different anions, using vibrational spectroscopy (Raman and IR), especially resonance Raman spectroscopy, allied with theoretical calculations based on density functional theory (DFT). The vibrational spectroscopic results (Raman and IR) showed changes in the position and shape of the band assigned to the symmetric stretching mode vs(SO2) depending on the anion and SO2 concentration in LI. There were significant shifts to lower wavenumbers with respect to pure liquid SO2 (1145 cm-1) at lower SO2 concentrations in IL. In the series of halides, Cl-, Br- and I-, the bigger the anion, the larger the displacement (1138, 1133 and 1123 cm-1, respectively at 0.5 mole fraction). In the case of thiocyanate, regarded as a pseudo-halide, the band vs(SO2) appears at about 1130 cm-1 at the same molar fraction, i.e. at an intermediate value between the Br- and I-. The observed displacement can be interpreted accordingly to the specific interaction of charge transfer from the anion to SO2. A result that is worth mentioning is the dependence of the wavenumber of the Raman band vs(SO2) with the energy of the exciting radiation, which is called Raman scattering. This phenomenon could be explained using the model of \"solvation state selective excitation\" in which was possible to characterize the diferente solvation states of the SO2 in ionic liquids
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Zhang, Ping. "SO2 Adsorption an Aktivkohle mit geringer Konzentration in Luft." Aachen Shaker, 2008. http://d-nb.info/992012538/04.
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Kurenko, Landin Roman, and Balwan Rana. "The Atmospheric SO2 Distribution and Volcanic Activity on Io." Thesis, KTH, Skolan för elektroteknik och datavetenskap (EECS), 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-254261.
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Io is the innermost Galilean moon of Jupiter and is considered the most volcanically active body in our solar system. With the help of the Hubble Space Telescope’s (HST) on-board Space Telescope Imaging Spectrograph (STIS), far-ultraviolet (FUV) images of Io have been captured for the past 20 years. The final goal of this project is to study the sulphur dioxide (SO2) distribution and volcanic activity on Io in FUV data taken in 1997/98 and 2013/14. The method used concerns the conversion of spectral Lyman-α intensity to SO2 density using algorithms implemented in MATLAB. As a result the SO2 distribution and volcanic activity on Io were determined and compared between the data collections. We found that the SO2 was higher in the images from 1997/98 compared to 2013/2014.
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Bruggeman, Karla E. "The effects of elimination and non-elimination games on physical activity and psychosocial responses in children." Thesis, Manhattan, Kan. : Kansas State University, 2008. http://hdl.handle.net/2097/747.
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Schwöbel, Frank. "Execution and elimination of apoptotic cells." [S.l.] : [s.n.], 2002. http://deposit.ddb.de/cgi-bin/dokserv?idn=965885003.
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Lakhal, Anen [Verfasser]. "Elimination in Operator Algebras / Anen Lakhal." Kassel : Universitätsbibliothek Kassel, 2014. http://d-nb.info/1059428962/34.
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Black, John Adrian. "Incorrigibility and elimination : a mentalist response." Thesis, University of British Columbia, 1987. http://hdl.handle.net/2429/26960.
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This essay is primarily an examination of a view,
propounded by Richard Rorty at the beginning of the last
decade, about the nature and existence of minds and mental
states. The view is a species of eliminative materialism, and
one which is of historical importance in the development of
this general position. I argue that it is false. I also
attempt to draw some positive conclusions in the philosophy of
mind from a criticism of some of its underlying assumptions.
Rorty's fundamental idea is that the belief in the
existence of minds and mental states is a primitive scientific theory, which in all likelihood is soon to be overthrown by the superior theory of neurophysiology. It will then be rational, he claims to deny the existence of minds and mental
states. Essential to Rorty's argument for this view is the
notion that mental states have a property which the neural
states of the replacing theory lack, namely of being the proper subjects of certain in corrigible reports, and which prevents the identification of the two. I undermine this argument by showing that ( i ) incorrigibility is not the mark of the mental and ( ii ) even if it were, it could not ground the categorical gulf which Rorty sees between mental and physical. I turn then to the major presupposition of the view, that mental states are theoretical entities posited in the causal explanation of behaviour, to see if this characterisation of the mental is an hypothesis adequate to account for the various phenomena of mental discourse. After examining reason-explanation, causal explanation in terms of mental states, the reporting role of mental ascriptions and the non-constative uses of mental language, I find that it is not.
In particular, Rorty's view cannot account for the limited extent to which certain mental reports are incorrigible, nor for the validity of justificatory and non-constative uses of mental language. I argue that the existence of mental states is guaranteed by this validity, and therefore that the issue of their elimination goes beyond considerations of theoretical superiority to the very fabric of human interaction, moral and otherwise. I emerge with the view that ordinary language and neurophysiology are compatible ways of describing people and their behaviour, and that far from being the murky posits of some proto-scientific folk-psychology, mental states are known to exist.Arts, Faculty of
Philosophy, Department of
Graduate
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Amyes, T. L. "Mechanisms of carboxyl-activated elimination reactions." Thesis, University of Cambridge, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.383698.
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Bell, Kathryn Emma. "Advances in the retro-Cope elimination." Thesis, University of Nottingham, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.307744.
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Cleator, Edward. "Applications of the reverse Cope elimination." Thesis, University of Liverpool, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.250235.
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Bento, Inês Fernandes. "Centriole elimination in Drosophila melanogaster oogenesis." Doctoral thesis, Universidade Nova de Lisboa. Instituto de Tecnologia Química e Biológica, 2012. http://hdl.handle.net/10362/10588.
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Dissertation presented to obtain the Ph.D degree in Cellular BiologyThe centriole is a Eukaryotic organelle involved in a variety of processes. Within the cytoplasm the centriole is part of the centrosome, the major microtubule (MT) organizing center in animal cells. The centrosome is involved in the regulation of cell motility and polarity in interphase and the organization of the mitotic spindle in mitosis. Each centrosome is composed of two centrioles surrounded by a protein-rich matrix, the pericentriolar material (PCM) (reviewed by Bettencourt-Dias and Glover, 2007) .(...)
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Chambrin, Hélène. "Elimination des déchets d'activités de soins." Paris 5, 1994. http://www.theses.fr/1994PA05P123.
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Hong, Hoon. "Improvements in CAD-based quantifier elimination /." The Ohio State University, 1990. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487684245468432.
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Ivashechkin, Pavel. "Elimination organischer Spurenstoffe aus kommunalem Abwasser." Aachen : Ges. zur Förderung der Siedlungswasserwirtschaft an der RWTH Aachen, 2006. http://bvbr.bib-bvb.de:8991/F?func=service&doc_library=BVB01&doc_number=015644505&line_number=0001&func_code=DB_RECORDS&service_type=MEDIA.
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Emiris, Ioannis Z. "Sparse elimination and applications in kinematics /." Berkeley, CA US : Univ. of California at Berkeley, 1994. http://www-sop.inria.fr/saga/personnel/Ioannis.Emiris/index.html.
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Azouit, Rémi. "Elimination adiabatique pour systèmes quantiques ouverts." Thesis, Paris Sciences et Lettres (ComUE), 2017. http://www.theses.fr/2017PSLEM008/document.
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Cette thèse traite du problème de la réduction de modèle pour les systèmes quantiquesouverts possédant différentes échelles de temps, également connu sous le nom d’éliminationadiabatique. L’objectif est d’obtenir une méthode générale d’élimination adiabatiqueassurant la structure quantique du modèle réduit.On considère un système quantique ouvert, décrit par une équation maîtresse deLindblad possédant deux échelles de temps, la dynamique rapide faisant converger lesystème vers un état d’équilibre. Les systèmes associés à un état d’équilibre unique ouune variété d’états d’équilibre ("decoherence-free space") sont considérés. La dynamiquelente est traitée comme une perturbation. En utilisant la séparation des échelles de temps,on développe une nouvelle technique d’élimination adiabatique pour obtenir, à n’importequel ordre, le modèle réduit décrivant les variables lentes. Cette méthode, basée sur undéveloppement asymptotique et la théorie géométrique des perturbations singulières, assureune bonne interprétation physique du modèle réduit au second ordre en exprimant ladynamique réduite sous une forme de Lindblad et la paramétrisation définissant la variétélente dans une forme de Kraus (préservant la trace et complètement positif). On obtientainsi des formules explicites, pour calculer le modèle réduit jusqu’au second ordre, dans lecas des systèmes composites faiblement couplés, de façon Hamiltonienne ou en cascade;des premiers résultats au troisième ordre sont présentés. Pour les systèmes possédant unevariété d’états d’équilibre, des formules explicites pour calculer le modèle réduit jusqu’ausecond ordre sont également obtenuesThis thesis addresses the model reduction problem for open quantum systems with differenttime-scales, also called adiabatic elimination. The objective is to derive a generic adiabaticelimination technique preserving the quantum structure for the reduced model.We consider an open quantum system, described by a Lindblad master equation withtwo time-scales, where the fast time-scale drives the system towards an equilibrium state.The cases of a unique steady state and a manifold of steady states (decoherence-free space)are considered. The slow dynamics is treated as a perturbation. Using the time-scaleseparation, we developed a new adiabatic elimination technique to derive at any orderthe reduced model describing the slow variables. The method, based on an asymptoticexpansion and geometric singular perturbation theory, ensures the physical interpretationof the reduced second-order model by giving the reduced dynamics in a Lindblad formand the mapping defining the slow manifold as a completely positive trace-preserving map(Kraus map) form. We give explicit second-order formulas, to compute the reduced model,for composite systems with weak - Hamiltonian or cascade - coupling between the twosubsystems and preliminary results on the third order. For systems with decoherence-freespace, explicit second order formulas are as well derived
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Jin, Hailiang. "Development of Polymeric SO2 Resistant Coating for Solid Amine Sorbent." University of Akron / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=akron1428180854.
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Wu, Wai Man. "Statistical analysis on SO2, O3 and PM10 in Hong Kong /." View Abstract or Full-Text, 2003. http://library.ust.hk/cgi/db/thesis.pl?MATH%202003%20WU.
Full textAbstract:
Thesis (M. Phil.)--Hong Kong University of Science and Technology, 2003.Includes bibliographical references (leaves 76-77). Also available in electronic version. Access restricted to campus users.
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Ma, Jianqiang. "Photodissociation Dynamics and Collision Energy Transfer of Highly Excited SO2." Diss., Temple University Libraries, 2011. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/213110.
Full textAbstract:
ChemistryPh.D.
As one of the simplest tri-atomic molecules, SO2 is extremely important in various fields in chemistry. SO2 is released by volcanoes and various industrial processes including combustion of sulfur containing fuel, and is well known to be the key chemical that causes the acid rain on earth. Therefore, SO2 has been studied intensively in both atmospheric chemistry as well as combustion chemistry. SO2 has also been discovered in extraterrestrial environment. For example, it is reported to be the most abundant gas observed in the atmosphere of Jupiter's moon, Io[1]. It has therefore generated great interests in the planetary chemistry as well. Even though understanding the structure, spectroscopy and reaction dynamics of SO2 has been of great and fundamental interests for more than 50 years, there are yet some very interesting topics, particularly those related to highly excited SO2, that require further investigations. In this thesis, we combine time-resolved Fourier transform infrared emission spectroscopy with theoretical modeling to study selected interesting problems relevant to highly excited SO2. First, the photodissociation of SO2 molecule by 193 nm photons is investigated. The role of different predissociation channels of electronically excited SO2 is carefully defined. Secondly, the excitation of SO2 by hot H atoms, a topic important in combustion and atmospheric chemistry, is examined. The energy transfer mechanism is identified and discussed. This newly discovered energy transfer mechanism involves the formation of the reactive intermediate species, which will greatly enhance the energy transfer efficiency on top of the classical impulsive type of collision mechanisms. In addition, the collision quenching of highly vibrationally excited SO2 with about 32,000 cm-1 energy is studied. It is found that the long range interactions contribute significantly to vibration to vibration (V-V) energy transfer. The contributions from both long range and impulsive mechanisms are discussed in detail. The studies presented in this thesis have provided important insight on the collision energy transfer and reaction dynamics of highly excited SO2 that would be useful in assessing the behavior of this important molecule in atmospheric, planetary, and combustive environments.
Temple University--Theses
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Exner, Karsten. "Bewitterung von Kalk- und Zementmörteln mit CO2, SO2 und NO x." [S.l. : s.n.], 2000. http://deposit.ddb.de/cgi-bin/dokserv?idn=960940944.
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Campion, Robin. "Imaging measurements of volcanic SO2 using space and ground based sensors." Doctoral thesis, Universite Libre de Bruxelles, 2011. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/209886.
Full textAbstract:
Sulfur dioxide (SO2) is a gas typical of high temperature magmatic degassing, being itsthird most abundant constituent after water vapor and carbon dioxide. SO2 flux measurements
are used to characterized and monitor volcanic degassing. This thesis presents advanced
methods for measuring the SO2 emitted in the troposphere by passive degassing volcanoes.
These methods are based on the absorption of infrared (IR) and ultraviolet (UV) light by SO2
molecules. They make use of the data acquired by satellite borne sensors (ASTER, OMI and
MODIS), and collected in the field using a UV camera equipped with filters
ASTER is a multispectral sensor observing the Earth in the thermal IR with a 90 m
ground resolution. The developed retrieval algorithm works with band ratios
(B10+B12)/2B11 and B14/B11, to avoid spectral interference from other variables than SO2.
With this algorithm, the impact of interferers such as atmospheric water vapor, sulfate
aerosols and ground emissivity is minimal, as demonstrated by radiative transfer simulations
by applying of the algorithm to real ASTER images and by comparing the results with ground
based data. ASTER is a kind of unifying thread for this thesis because its high ground
resolution fills the gap existing between highly localized ground based SO2 measurements and
the global coverage of other satellites with coarser pixels such as OMI and MODIS.
OMI is an imaging spectrometer operating in the UV, with a daily global coverage, a
high sensitivity to SO2 and a ground resolution of 13x24km. The OMI-ASTER comparison
shows that the SO2 columns measured on OMI pixels are two orders of magnitude smaller
than those of ASTER, because of the huge difference in the pixel size of the two satellites.
The flux measurements however are generally in good agreement. The analysis of a large
number of images shows that ASTER is better for cloud free scenes while OMI has an
optimal signal to noise ratio when the plume is lying above a low cloud cover. A practical
detection limit for SO2 flux measurements in tropospheric plumes has also been established:
5kg/s.
The comparison between ASTER measurements of SO2 column amounts with those of
MODIS (a multispectral IR imager with 1km ground resolution) shed light on systematic
errors in MODIS measurements. These errors were quantified and their origins were separated
and identified. This work demonstrates the limitations of MODIS for SO2 measurements.
A UV camera equipped with filters has also been developed to achieve 2D SO2 from the
ground at a high spatial and temporal resolution. The potential provided by this new type of
instruments has been demonstrated during a field campaign on Turrialba Volcano (Costa
Rica). The integration of measurements obtained using the camera, ASTER and OMI revealed
a high and sustained SO2 flux, which can be explained only by the degassing of a recently
intruded magma body. The slow decrease of SO2 flux since January 2010 suggests a
progressive exhaustion of the volatile content of the magma.
Finally, we applied the band ratio algorithm to a series of ASTER images of the recent
eruption of Eyjafjallajökull in April-May 2010. The SO2 measurements provide interesting
insights into the complex eruptive dynamics and into the control of hydromagmatic
interactions on eruptive gas release into the atmosphere. /
Le dioxyde de soufre (SO2) est un gaz typique du dégazage magmatique de haute
température, dont il est le troisième composant le plus abondant derrière H2O et CO2. Le flux
de SO2 est un excellent paramètre pour caractériser le dégazage volcanique et surveiller son
évolution dans le temps. Cette thèse présente de nouvelles méthodes de mesures des flux de
SO2 émis par l’activité volcanique. Ces méthodes se basent sur l’absorption de la molécule de
SO2 dans l’infrarouge (IR) et l’ultraviolet (UV). Elles utilisent les données prises par des
senseurs embarqués sur des satellites (ASTER, OMI et MODIS) ou opérés depuis le sol
(caméra UV munie de filtres).
Le senseur ASTER opère dans l’IR thermique avec une résolution spatiale de 90 m par
pixel. L’algorithme de mesure développé pour ce satellite n’est sensible qu’à la concentration
en SO2 et pratiquement pas aux paramètres interférents qui posaient problèmes aux méthodes
existantes :la vapeur d’eau atmosphérique, les aérosols de sulfate dans le panache et
l’émissivité de la surface sous-jacente. ASTER est un peu le fil conducteur de cette thèse, car
sa haute résolution spatiale lui permet de faire le lien entre des mesures au sol et les mesures
faites par d’autres satellites comme OMI et MODIS.
Le satellite OMI est un spectromètre imageant qui opère dans l’UV, avec une
couverture globale journalière, une haute sensitivité au SO2 et une résolution spatiale de
13x24km. La comparaison OMI-ASTER montre que les colonnes mesurées sur les pixels
d’OMI sont de deux ordres de grandeur inférieurs à celles d’ASTER, à cause de la différence
de résolution spatiale entre les deux satellites. Les mesures de flux, par contre, montrent une
très bonne concordance. L’analyse d’un grand nombre d’images a permis d’établir qu’ASTER
est meilleur pour des scènes sans nuages tandis qu’OMI est meilleur quand une couverture
nuageuse présente sous le panache augmente son rapport signal sur bruit. Une limite de
détection pratique a aussi été établie pour les flux de SO2 dans les panaches volcaniques dans
la basse troposphère :5kg/s.
La comparaison des mesures d’ASTER avec celle de MODIS a permis de démontrer les
limites de MODIS pour la mesure du SO2. Des erreurs systématiques sur les mesures de
MODIS on été mises en évidence et quantifiées. Ces erreurs sont dues aux interférents
spectraux que sont la vapeur d’eau atmosphérique et les aérosols sulfatés. L’émissivité est
aussi un important facteur d’erreur pour MODIS.
Une caméra UV équipée d’un système de filtres a également été développée pour
mesurer le SO2 en 2D, à haute résolution spatiale et temporelle. Le potentiel offert par ce
nouveau type d’instrument a été démontré lors d’une campagne de mesures sur le volcan
Turrialba (Costa Rica). La combinaison de mesures de SO2 réalisée avec la caméra, ASTER
et OMI a permis de mettre en évidence des flux très élevés (30-50kg/s) qui ne peuvent
s’expliquer que par une intrusion récente de magma juvénile en cours de dégazage.
Enfin, les mesures de SO2 ont réalisées à partir des images ASTER pendant l’éruption
du volcan Eyjafjallajökull en avril-mai 2010. Ces mesures fournissent des informations
intéressantes sur les dynamismes éruptifs qui se sont succédé et sur le contrôle des émissions
de SO2 dans l’atmosphère par les interactions magma-eau.
Doctorat en Sciences
info:eu-repo/semantics/nonPublished
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Lowe, Miranda Jeanne. "Sources of ambient Sulfur Dioxide (SO2) in the metro Atlanta area." Available online, Georgia Institute of Technology, 2007, 2007. http://etd.gatech.edu/theses/available/etd-04082007-231954/.
Full textAbstract:
Thesis (M. S.)--Civil and Environmental Engineering, Georgia Institute of Technology, 2007.Dr. James Mulholland, Committee Chair ; Dr. Armistead Russell, Committee Member ; Dr. Michael Bergin, Committee Member.
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Schoeman, Johannes Gerhardus. "H2SO4 stability of PBI–blend membranes for SO2 electrolysis Schoeman / H." Thesis, North-West University, 2011. http://hdl.handle.net/10394/7567.
Full textAbstract:
Alternative energy sources are needed if the current use of energy is to be sustained while
reducing global warming. A possible alternative energy source that has significant potential
is hydrogen. For hydrogen to become a serious contender for replacing fossil fuels, the
production thereof has to be further investigated. One such process, the membrane–based
Hybrid Sulphur (HyS) process, where hydrogen is produced from the electrolysis of SO2, has
received considerable interest recently.
Since H2SO4 is formed during SO2 electrolysis, H2SO4 stability is a prerequisite for any
membrane to be used in this process. In this study, pure as well as high and low
temperature blended polybenzimidazole (PBI), partially fluorinated poly(arylene ether) (sFS)
and nonfluorinated poly(arylene ethersulphone) (sPSU) membranes were investigated in
terms of their acid stability as a function of acid concentration by treating them in H2SO4 (30,
60 and 90wt%) for 120h at 1bar pressure. The high temperature blend membranes contain
the basic polymer in excess (70 wt% basic PBI and 30wt% acid sPSU/sFS polymer) and
require acid doping in order to conduct protons. In the doped state they are able to conduct
protons up to 200°C. The low temperature blend membranes are also composed of the
same PBI polymer used in the high temperature membranes, as well as the same acidic
polymers with one of the membranes containing a fluorinated polymer and the other a nonfluorinated
polymer (sFS or sPSU) in excess. These membranes do not require any acid
doping to conduct protons but they are only stable at temperatures below 80°C.
High temperature blend membranes were characterised using through–plane conductivity,
GPC and IEC, whilst low temperature membranes were characterised using in–plane and
through–plane proton conductivity, weight change, TGA, GPC, SEM, EDX and IEC
techniques. The conductivity determination techniques (especially the in–plane technique)
proved to be cumbersome, whilst all the other analysis techniques were deemed
appropriate.
H2SO4 exposure had a destabilising effect on the PBI membrane which presented as weight
gain at the 30 and 60wt% H2SO4 concentrations due to salt formation and dissolution at the
90wt% acid treatment due to sulphonation. In the sFS membrane dissolution was observed
at 30 and 60wt% as a result of oligomer loss that occurred during the post treatment
washing process and partial dissolution, as a result of sulphonation, at the 90wt% treated membrane. The sPSU membrane showed great stability at 30 and 60wt%, though
dissolution was observed at 90wt% because of membrane sulphonation due to a lack of
fluorination. The sFS–PBI membrane blend proved to be stable with only slight degradation
taking place at 90wt% treatment due to sulphonation. Similarly the sPSU–PBI blend
membrane showed great stability at the 30 and 60wt% H2SO4 treatment concentrations
however total dissolution occurred at 90wt% treatment again due to a lack of fluorination.
Although both the low temperature blended membranes showed superb stability to H2SO4
concentrations expected in the SO2 electrolyser (30–40wt%), the low temperature blended
sFS–PBI membrane seemed slightly more stable over the H2SO4 treatment concentration
range (30–90wt%), due to the protective role of the fluorinated polymer. The superior acid
stability of this membrane could prove vital for proper SO2 electrolysis, especially for
prolonged periods of operationThesis (M.Sc. (Pharmaceutical Chemistry))--North-West University, Potchefstroom Campus, 2012.
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Rabie, Samuel Liversage. "SO2 and O2 separation by using ionic liquid absorption / S.L. Rabie." Thesis, North-West University, 2012. http://hdl.handle.net/10394/9100.
Full textAbstract:
In order to reduce the amount of pollution that is generated by burning fossil fuels alternative
energy sources should be explored. Hydrogen has been identified as the most promising
replacement for fossil fuels and can be produced by using the Hybrid Sulphur (HyS) cycle.
Currently the SO2/O2 separation step in the HyS process has a large amount of knock out
drums. The aim of this study was to investigate new technology to separate the SO2 and O2.
The technology that was identified and investigated was to separate the SO2 and O2 by
absorbing the SO2 into an ionic liquid.
In this study the maximum absorption, absorption rate and desorption rate of SO2 from the
ionic liquid [BMIm][MeSO4] with purities of 95% and 98% was investigated. These ionic liquid
properties were investigated for pure O2 at pressures ranging from 1.5 to 9 bar(a) and for
pure SO2 at pressures from 1.5 to 3 bar(a) at ambient temperature. Experiments were also
carried out where the composition of the feed-stream to the ionic liquid was varied with
compositions of 0, 25, 50, 75 and 100 mol% SO2 with O2 as the balance. For each of these
compositions the temperature of the ionic liquid was changed from 30oC to 60oC, in
increments of 10oC.
The absorption rate of SO2 in the ionic liquid increased when the mole percentage SO2 in the
feed stream was increased. When the temperature of the ionic liquid was decreased the
maximum amount of SO2 that the ionic liquid absorbed increased dramatically. However, the
absorption rate was not influenced by a change in the absorption temperature.
The experimental results for the maximum SO2 absorption were modelled with the Langmuir
absorption model. The model fitted the data well, with an average standard deviation of
17.07% over all the experiments. In order to determine if the absorption reaction was
endothermic or exothermic the Clausius-Clapeyron equation was used to calculate the heat
of desorption for the desorption step. The heat of desorption data indicated that the
desorption of SO2 from this ionic liquid was an endothermic reaction because the heat of
desorption values was positive. Therefore the absorption reaction was exothermic.
From the pressure-change experiments the results showed that the mole percentage of O2
gas that was absorbed into the ionic liquid was independent of the pressure of the O2 feed.On the other hand, there was a clear correlation between the mole percentage SO2 that was
absorbed into the ionic liquid and the feed pressure of the SO2. When the feed pressure of
the SO2 was increased the amount of SO2 absorbed also increased, this trend was
explained with Fick’s law.
In the study the effect of the ionic liquid purity on the SO2 absorption capacity was
investigated. The experimental results for the pressure experiments showed that the 95%
and 98% pure ionic liquid absorbed about the same amount of SO2. During the temperature
experiments the 95% pure ionic liquid absorbed more SO2 than the 98% pure ionic liquid for
all but two of the experiments. However the 95% pure ionic liquid also absorbed small
amounts of O2 at 30 and 40oC which indicated that the 95% pure ionic liquid had a lower
selectivity than the 98% pure ionic liquid. Therefore, the 95% pure ionic liquid had better SO2
absorption capabilities than the 98% pure ionic liquid.
These result showed that the 98% pure ionic liquid did not absorb more SO2 than the 95%
pure ionic liquid, but it did, however, show that the 98% pure ionic liquid had a better
selectivity towards the SO2. Hence, it can be concluded that even with the O2 that is
absorbed it would be economically more advantageous to use the less expensive 95% pure
ionic liquid rather than the expensive 98% pure ionic liquid, because the O2 would not
influence the performance of the process negatively in such low quantities.Thesis (MIng (Chemical Engineering))--North-West University, Potchefstroom Campus, 2013
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Hlabano-Moyo, Bongibethu Msekeli. "Separation of SO2/O2 using membrane technology / Bongibethu Msekeli Hlabano-Moyo." Thesis, North-West University, 2013. http://hdl.handle.net/10394/9447.
Full textAbstract:
The Hybrid Sulphur process is one technology out of a multitude of known technologies responsible for hydrogen production. Within the latter hydrogen production cycle, it is pivotal to recover O2 as a by-product from a sulphuric acid decomposition reaction that produces SO2, H2O and O2. It is assumed that a simple phase separation stage carried out on the reaction products would liberate SO2 and O2 as a gaseous mixture leaving behind H2O in the liquid state.
Several separation technologies are available to effect SO2/O2 separation, but membrane technology has proved to be dearer due to simplicity of the technology, low capital and energy costs. It is a pity though that insignificant work has been done that considers the SO2/O2 binary system in the membrane technology context. Of the insignificant work done, non – commercial membranes were employed. It is on the latter background that the present study was proposed.
Six commercial membranes were selected from literature, two (Udel Polysulfone and Teflon AF 2400) of which are currently used in gas separation applications and the remainder (Hyflon M, Hyflon F, Halar and Nafion 117) not necessarily used as gas separation membranes but present a potential of separating SO2/O2. The inclusion of the latter four membranes sought to unearth unknown gas separation potentials of the membranes based on hypothetical 1 μm thick membranes.
A screening technique was employed to eliminate poor performing membranes through pure component permeation of SO2, O2, N2 and CO2. The use of the additional gases (N2 and CO2) was meant to allow the generation of a pool of data that would be used as a yardstick to compare to literature and thus validate the authenticity of the designed set up. The single permeation experiments were carried out at 25°C and at absolute gas feed pressures of 1 bar, 2 bar and 3 bar, with the exception of Hyflon F experiments that were carried out at 3.85 bar, 2.85 bar and 1.85 bar also at 25°C. The effect of pressure on gas permeability and ideal selectivity of all gases against O2 was investigated. Udel Polysulfone and Nafion 117 presented clearly evident pressure dependant SO2 permeabilities whilst CO2, N2 and O2 permeabilities were sluggishly dependant on pressure in all membranes. Gas flux in general increased with increasing pressure as pressure is essentially the driving force for permeability. Membrane screening for further investigation was then performed based on a compromise between SO2/O2 ideal selectivity and SO2 flux in hypothetical 1 μm thick membranes. Membranes that presented the best SO2/O2 selectivity include, Udel Polysulfone with SO2/O2 selectivities of 46, 58 and 314 at 1 bar, 2 bar and 3 bar respectively, Nafion 117 with SO2/O2 selectivities of 30, 35 and 40 at 1 bar, 2 bar and 3 bar respectively and Halar with a SO2/O2 selectivity of 17 at 3 bar. The best SO2 flux through hypothetical 1 μm thick membranes was manifested in Teflon AF 2400 with SO2 fluxes of 3.6 m3.m-2.hr-1, 5.9 m3.m-2.hr-1 and 9.9 m3.m-2.hr-1 at trans-membrane pressures of 1 bar, 2 Bar and 3 Bar respectively, Udel Polysulfone with SO2 fluxes of 0.13 m3.m-2.hr-1, 0.32 m3.m-2.hr-1 and 2.56 m3.m-2.hr-1 at trans-membrane pressures of 1 bar, 2 bar and 3 bar respectively and Nafion 117 with SO2 fluxes of 0.48 m3.m-2.hr-1, 1.03 m3.m-2.hr-1 and 1.79 m3.m-2.hr-1 at 1 bar, 2 bar and 3 bar trans-membrane pressures respectively. Despite Teflon AF 2400 presenting the highest SO2 flux, the poor SO2/O2 ideal selectivity ≈ 1 rendered the membrane unfit for further investigation. The low SO2 flux (0.02 m3.m-2.hr-1) presented by Halar also rendered the membrane unfit for further investigation despite the relatively fair SO2/O2 ideal selectivity of 17.
Binary permeation experiments were then performed on Udel Polysulfone and Nafion 117 after passing the single permeation screening test. Gas mixture compositions of (25 wt %:75 wt %, SO2:O2), (50 wt %:50 wt %, SO2:O2) and (75 wt %:25 wt %, SO2:O2) were employed. The binary permeation experiments were carried out at a temperature range of 15°C to 55°C and a SO2 feed partial pressure range of 1.1 ± 0.1 bar to 2.3 ± 0.1 bar.
The SO2 permeate composition increased with pressure and decreased with temperature in both Udel Polysulfone and Nafion 117. Udel Polysulfone presented a superior SO2/O2 separation potential, concentrating a (25 wt %:75 wt %, SO2:O2) gas mixture to (94 wt %:6 wt %, SO2:O2) in a single step at 15°C and 2.2 ± 0.1 bar SO2 feed partial pressure. Nafion 117 concentrated the same gas mixture to (87 wt %:13 wt %, SO2:O2) also in a single step at 15 °C and 2.4 ± 0.1 bar SO2 feed partial pressure. Based on hypothetical 1 μm thick membranes, Nafion 117 presented generally high SO2 molar fluxes in mixture with O2 of about a magnitude higher than the SO2 molar fluxes presented in Udel Polysulfone. Also, Nafion 117 proved to be less prone to plasticisation within the pressure range considered. Despite Udel Polysulfone presenting generally lower SO2 molar fluxes, Udel Polysulfone was deemed to be the ideal membrane for the current SO2/O2 separation application as thicknesses of 1 μm of Nafion the perfluorosulfonic acid based membrane are currently unknown and also Udel Polysulfone presented the best SO2/O2 separation capability. The latter findings are envisaged to prompt further research on the production of ultra-thin perfluoro-sulfonic acid based membranes for the current application.Thesis (MIng (Chemical Engineering))--North-West University, Potchefstroom Campus, 2013