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1
Hoorn, Johannes Adriaan Aris. "Aspects of mass transfer in gas-liquid oxidation reactions." Enschede : University of Twente [Host], 2005. http://doc.utwente.nl/50858.
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Hall, Charles A. "Kinetics and mass-transfer effects in batch alkoxylations." Thesis, Georgia Institute of Technology, 1987. http://hdl.handle.net/1853/11213.
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Ison, Andrew Phillip. "Mass transfer effects in fat interesterification reactions catalysed by immobilized lipase." Thesis, University College London (University of London), 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.262823.
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Barhey, Avtar Singh. "Process intensification for gas-liquid reactions." Thesis, University of Nottingham, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.318719.
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Trikoupis, Moschoula Anna. "A mass spectrometric and computational study of hydrogen transfer reactions in radical cations /." *McMaster only, 2001.
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Xu, Yaodong. "Applications of mass spectrometric techniques to charge-transfer processes and cluster ion reactions." Diss., Georgia Institute of Technology, 1991. http://hdl.handle.net/1853/26208.
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Shields, George Charles. "Investigation of structures and reactivities of hydrocarbon ions through gaseous charge transfer reactions." Diss., Georgia Institute of Technology, 1986. http://hdl.handle.net/1853/30893.
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McCoskey, Jacob K. "Sample dehumidification to enhance formaldehyde detection by a proton transfer reaction mass spectrometer." Pullman, Wash. : Washington State University, 2009. http://www.dissertations.wsu.edu/Thesis/Summer2009/J_McCoskey_072109.pdf.
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Thesis (M.S. in environmental engineering)--Washington State University, August 2009.<br>Title from PDF title page (viewed on Aug. 7, 2009). "Department of Civil and Environmental Engineering." Includes bibliographical references (p. 73-76).
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Darmana, Dadan. "On the multiscale modelling of hydrodynamics, mass transfer and chemical reactions in bubble columns." Enschede : University of Twente [Host], 2006. http://doc.utwente.nl/57598.
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Mutasher, Emad Ismail. "Mass and heat transfer in non-catalytic gas-solid reactions : applications in flue gas desulphurisation." Thesis, Swansea University, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.330016.
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Pollet, Benoît. "Transport-reactions dans les membranes echangeuses d'ions : extraction et transport facilites d'acides faibles, cas particulier de l'acide borique." Paris 6, 1987. http://www.theses.fr/1987PA066584.
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Le transport de substrat a travers une membrane echangeuse d'ions peut etre accelere lorsqu'un contre ion joue le role de transporteur. L'acide borique par reaction de neutralisation avec le contre ion hydroxyle et par reaction de condensation avec l'ion borate forme des complexes polyborates (tri-, tetra- et penta-borates) de stabilite moyenne
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Widmann, John F. "Chemical reaction and thermodynamic studies of microparticles using electrodynamic balances /." Thesis, Connect to this title online; UW restricted, 1997. http://hdl.handle.net/1773/9873.
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URBANI, DANIELE. "Overcoming light and mass transfer phenomena in gas-liquid biphasic reactions: introduction of the aerosol methodological paradigm." Doctoral thesis, Università degli studi di Ferrara, 2022. http://hdl.handle.net/11392/2496482.
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Overcoming light and mass transfer phenomena in gas-liquid biphasic reactions: introduction of the aerosol methodological paradigm
Mass transfer phenomena are a limitation factor especially in gas-liquid organic chemistry reaction. This issue can be overcome by exploiting the huge increase of the surface to volume ratio when spraying the reaction solution. Each droplet generated this way will react as a single reactor.
In this thesis the selective photo-oxidation of organic sulfides to sulfoxides and the utilization of CO2 for the synthesis of cyclic carbonates from the corresponding epoxides are both widely studied.
A model reaction has been chosen for the study of the photochemical oxidation of a water soluble sulfide to the corresponding sulfoxide mediated by singlet oxygen:
For this reaction several setup were built with the aim of enhancing the final conversion and the mass recovery of the process. A photochemical aerosol reactor was design and built in collaboration with the University of KULeuven to obtain allowing us to reach 95% conversion and complete selectivity toward the sulfoxide. The acceleration factor of the reaction kinetic is 144 compared to the bulk reaction.
The scope expansion of the model reaction towards organic sulfides that are not soluble in water was then carried on to place the foundation for further aerosol experiments. In this case a water:ethanol mixture is choose as green solvent for safety and environmental issues.
Severe climate change represents a threat for human life, and its effects on environment, economic and social development is widely studied. Unequivocally scientific evidences link climate change to greenhouse gases emissions, and identify CO2 as a greenhouse gas.
For this reason we thought of using CO2 as a reactive-carrier gas to carry out the synthesis of styrene carbonate from styrene oxide:
This synthesis was identified as the model reaction for further studies.
Without any previous experience in this field an extensive study of the scientific literature was done with the aim of identifying the best catalyst suitable for an aerosol reactor. KI/tetraethylene glycol is choose as catalyst for the comparison between bulk and aerosol reaction due to its features.
The kinetic study at different temperature of the model reaction in bulk and aerosol batch condition was carried on giving an acceleration factor up to 1,85. Unfortunately it was impossible during the PhD period to work with an aerosol flow reactor for CO2 reaction due to inadequate reactor setup and low reactivity of the gas.
For this purpose a modular aerosol reactor has been design and built to being able, in the forthcoming future, to fully exploit microdroplets environment:
Even if several data were collected with extreme difficulties, due to the novel approach choose on CCU technologies, those were sufficient to obtain a partnership for a NATO project call TANGO. The research group will now focus on the synthesis of new catalysts supported on magnetic nanoparticles that, hopefully, can convert styrene oxide into styrene carbonate with high yield and faster reaction time. All the experiments necessary are going to be exploiting the modular reactor designed and built with the experience gained on the strictly homogeneous reaction. The model reaction reported in this thesis will be the benchmark for future reactions.<br>I fenomeni di trasferimento di massa sono un fattore limitante soprattutto nelle reazioni di chimica organica gas-liquido. Questo problema può essere superato sfruttando l'enorme aumento del rapporto superficie-volume quando si nebulizza una soluzione. Ogni goccia generata in questo modo reagirà come un singolo reattore.
In questa tesi sono ampiamente studiate sia la foto-ossidazione selettiva di solfuri organici a solfossidi, sia l'utilizzo di CO2 per la sintesi di carbonati ciclici partendo dai corrispondenti epossidi.
Una reazione modello è stata scelta per lo studio dell'ossidazione fotochimica di un solfuro solubile in acqua al corrispondente solfossido mediata dall’ ossigeno di singoletto:
Per questa reazione sono stati costruiti diversi setup strumentali con l'obiettivo di migliorare la conversione finale e il recupero di massa del processo. Un reattore aerosol fotochimico è stato quindi progettato e costruito in collaborazione con l'Università di KULeuven, permettendo di raggiungere il 95% di conversione finale e la completa selettività verso il solfossido. Il fattore di accelerazione della cinetica di reazione è 144 rispetto alle condizioni di reazione classica.
L'espansione metodologica della reazione modello verso solfuri organici non solubili in acqua è stata poi portata avanti in condizioni bulk ponendo le basi per ulteriori esperimenti in aerosol. In questo caso una miscela acqua:etanolo è stata scelta come solvente verde per questioni di sicurezza e sostenibilità ambientale.
I cambiamenti climatici rappresentano una minaccia per la vita umana, e i loro effetti sull'ambiente e sullo sviluppo economico e sociale sono ampiamente studiati. Evidenze scientifiche inequivocabili collegano il cambiamento climatico alle emissioni di gas a effetto serra ed identificano la CO2 come uno di questi gas.
Per questo motivo si è pensato di utilizzare la CO2 come gas reattivo nella sintesi dello stirene carbonato partendo dallo stirene ossido:
Questa sintesi è stata identificata come la reazione modello per studi futuri.
Senza alcuna esperienza precedente in questo campo è stato necessario effettuare un ampio studio della letteratura scientifica con l'obiettivo di identificare il miglior catalizzatore adatto ad un reattore aerosol. Il complesso KI/tetraetilen glicole è stato scelto come catalizzatore per il confronto tra la reazione bulk e quella aerosol per le sue caratteristiche, ideali per questa tipologia di sintesi.
Lo studio cinetico a diverse temperature della reazione modello in condizioni di bulk e aerosol ha permesso di ottenere fattori di accelerazione fino a 1,85. Sfortunatamente non è stato possibile, durante il periodo di dottorato, lavorare con un reattore a flusso di aerosol per la reazione con la CO2 a causa della configurazione inadeguata dei reattori a disposizione e alla bassa reattività del gas.
Per ovviare a questa mancanza è stato progettato e costruito un reattore aerosol modulare potenzialmente in grado, nel prossimo futuro, di sfruttare pienamente i vantaggi dell'aerosol:
Nonostante la difficile raccolta dati, dettata del nuovo approccio scelto sulle tecnologie CCU, i risultati raggiunti sono stati sufficienti per ottenere un partenariato in un progetto NATO chiamato TANGO. Il gruppo di ricerca si concentrerà quindi sulla sintesi di nuovi catalizzatori supportati su nanoparticelle magnetiche che, si spera, possano convertire lo stirene ossido in stirene carbonato con un alta resa e tempi di reazione più rapidi. Tutti gli esperimenti necessari andranno a sfruttare il reattore modulare recentemente progettato e costruito a partire dall'esperienza maturata sulla reazione modello. La reazione modello riportata in questa tesi sarà anche il benchmark per le reazioni future.
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Moldovan, Stefan Ilie. "Numerical Simulation and Experimental Validation of Fluid Flow and Mass Transfer in an Ammonothermal Crystal Growth Reactor." University of Akron / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=akron1366033161.
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Hu, Xinqun. "Design of a microchannel reactor for gas phase heterogeneous reactions : enhanced mass and heat transfer for process intensification." Thesis, University of Sheffield, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.246984.
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Papadias, Dennis. "Mathematical Modelling of Structured Reactors with Emphasis on Catalytic Combustion Reactions." Doctoral thesis, Stockholm, 2001. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3212.
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Butson, Jeffery M. "Electron Transfer and Other Reactions Using Atomic Metal Anions." Thèse, Université d'Ottawa / University of Ottawa, 2014. http://hdl.handle.net/10393/30561.
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The atomic metal anions Rb-, Cs-, Cu-, Ag- and Fe- have been generated in the gas phase and reacted with various neutral reactants in a triple quadrupole mass spectrometer. The metal anions were formed via electrospray ionization of the metal-oxalate solutions and form in gas phase between the capillary and the first quadrupole. Neutral gas phase reactants investigated include NO, NO2, SO2, C6F5OH, C6F5NH2, C6F6, E-octafluoro-butene and 1,2,3/1,2,4/1,3,5 trifluoro-benzene. When possible, CBS-4M methods were used to suggest the lowest energy products based on relative energy. Observed reactions of atomic metal anions with the aforementioned neutral species include electron transfer and dissociative electron transfer to the neutral gas phase reactants. In addition, hydrogen abstraction and fluorine abstraction forming a neutral metal hydride or fluoride as well as the formation of multiply substituted metal-oxide/fluoride anions was also observed. Metal-complex anions observed from the gas phase reactions include CuF-,CuF2-,CuO-,CuO2-, FeO-, FeO2-, FeO3-, FeF-, FeF2-, FeF3-, CsF- and CsF2-.
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Wales, Michael Dean. "Membrane contact reactors for three-phase catalytic reactions." Diss., Kansas State University, 2015. http://hdl.handle.net/2097/20589.
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Doctor of Philosophy<br>Chemical Engineering<br>Mary E. Rezac<br>Membrane contact reactors (MCRs) have been evaluated for the selective hydro-treating of model reactions; the partial hydrogenation of soybean oil (PHSO), and the conversion of lactic acid into commodity chemicals. Membranes were rendered catalytically active by depositing metal catalyst onto the polymer "skin" of an asymmetric membrane. Hydrogen was supplied to the support side of the membrane and permeated from the support side to the skin side, where it adsorbed directly onto the metal surface. Liquid reactant was circulated over the membrane, allowing the liquid to come into direct contact with the metal coated surface of the membrane, where the reaction occurred. Our membrane contact reactor approach replaces traditional three-phase batch slurry reactors. These traditional reactors possess inherent mass transfer limitations due to low hydrogen solubility in liquid and slow diffusion to the catalyst surface. This causes hydrogen starvation at the catalyst surface, resulting in undesirable side reactions and/or extreme operating pressures of 100 atmospheres or more. By using membrane reactors, we were able to rapidly supply hydrogen to the catalyst surface.
When the PHSO is performed in a traditional slurry reactor, the aforementioned hydrogen starvation leads to a high amounts of trans-fats. Using a MCR, we were able to reduce trans-fats by over 50% for equal levels of hydrogenation. It was further demonstrated that an increase in temperature had minimal effects on trans-fat formation, while significantly increasing hydrogenation rates; allowing the system to capture higher reaction rates without adversely affecting product quality. Additionally, high temperatures favors the hydrogenation of polyenes over monoenes, leading to low amounts of saturated fats. MCRs were shown to operator at high temperatures and: (1) capture high reaction rates, (2) minimize saturated fats, and (3) minimize trans-fats.
We also demonstrated lactic acid conversion into commodity chemicals using MCRs. Our results show that all MCR experiments had faster reaction rate than all of our controls, indicating that MCRs have high levels of hydrogen coverage at the catalyst. It was also demonstrated that changing reaction conditions (pressure and temperature) changed the product selectivities; giving the potential for MCRs to manipulate product selectivity.
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Munisamy, Thiruvengadam Gipson Stephen L. "Electrochemistry and electron transfer induced substitution reactions of methylcyclopentadienylmolybdenum tricarbonyl complexes and electrospray ionization mass spectrometry and x-ray crystallographic characterization of related molybdenum complexes." Waco, Tex. : Baylor University, 2007. http://hdl.handle.net/2104/5234.
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Liu, Hang. "In situ investigations of chemical reactions on ZnO-Pt model nanocatalysts for environmentally friendly energy generation sources." Electronic Thesis or Diss., Sorbonne université, 2019. https://accesdistant.sorbonne-universite.fr/login?url=https://theses-intra.sorbonne-universite.fr/2019SORUS201.pdf.
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Il a été démontré que le catalyseur ZnO/Pt(111) présente des performances catalytiques remarquables dans l'oxydation du CO à basse température. L'identification des sites actifs dans l'oxydation du CO est importante pour une compréhension mécaniste de la relation structure-réactivité. Nous avons d'abord établi une recette pour fabriquer des films minces de ZnO sur Pt(111) par évaporation par faisceau électronique, caractérisée par STM et LEED. Le film se développe en mode couche par couche, à parti rd'une monocouche de type grapheme jusqu'à la surface ZnO(0001)-Zn terminée. Le rôle des limites ZnO/Pt a été révélé par la STM ex situ après exposition à l'O2:CO. Pour mettre en lumière le rôle des limites, une étude comparative systématique du catalyseur ZnO/Pt(111) avec la surface Pt(111) a été entreprise. La spectroscopie de masse et l'analyse NAP-XPS en phase gazeuse étaient pertinentes pour déterminer les régimes dans lesquels la limitation du transfert de masse commence à se produire, ce qui a permis de discuter de la relation entre les fractions molaires à l'état stable des réactifs/produit et la réactivité de surface, et pour étalonner la densité de surface des adsorbats. Les spectres XPS en phase solide nous ont donné accès à la dynamique du film monocouche ZnO ne couvrant que partiellement la surface Pt(111). Le rôle des hydroxyls liés au ZnO a été mis en évidence par l'observation de la signature chimique des produits de réaction associative CO+OH. Le carboxyle formé à basse temperature peut être l'espèce intermédiaire qui conduit à l'évolution du CO2, les OHs à la limite Pt/ZnO étant le co-catalyseur, ce qui explique l'effet synergique du ZnO et du Pt<br>The ZnO/Pt(111) catalyst has been shown to exhibit remarkable catalytic performances in the low temperature CO oxidation. The identification of the active sites in CO oxidation is important for a mechanistic understanding of the structure-reactivity relationship. We first established a recipe to fabricate ZnO thin films on Pt(111) using e-beam evaporation, characterized by STM and LEED. The film grows in layer-by-layer mode, starting from a graphene-like monolayer tothe ZnO(0001)-Zn terminated surface. The role of the ZnO/Pt boundaries was revealed by STM ex situ after exposure to the O2: CO mixture. To shedlight on the role of the boundaries, a systematic comparative study of the ZnO/Pt(111) catalyst with the Pt(111) surface was under taken. The mass spectroscopy and gas phase NAP-XPS analysis were relevant, to determine the regimes where mass transfer limitation starts to occur, allowing a discussion on the relation between steady-state molar fractions of reactants/product and surface reactivity, and to calibrate the surface density of the adsorbates.Solid phase XPS spectra gave us access to the dynamics of the ZnO monolayer film covering only partially the Pt(111) surface. The role of ZnO-bound hydroxyls was highlighted by the observation of the chemical signature of the CO+OH associative reaction products. The carboxyl formed at the low temperature can be the intermediate species that leads to the evolution of CO2, the OHs at the Pt/ZnO boundary being the co-catalyst, which explains the synergistic effect of ZnO and Pt
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Derdar, Mawaheb M. Zarok. "Experimental and kinetic modelling of multicomponent gas/liquid ozone reactions in aqueous phase. Experimental investigation and Matlab modelling of the ozone mass transfer and multicomponent chemical reactions in a well agitatated semi-batch gas/liquid reactor." Thesis, University of Bradford, 2010. http://hdl.handle.net/10454/4872.
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Due to the ever increasing concerns about pollutants and contaminants found in water, new treatment technologies have been developed. Ozonation is one of such technologies. It has been widely applied in the treatment of pollutants in water and wastewater treatment processes. Ozone has many applications such as oxidation of organic components, mineral matter, inactivation of viruses, cysts, bacteria, removal of trace pollutants like pesticides and solvents, and removal of tastes and odours. Ozone is the strongest conventional oxidant that can result in complete mineralisation of the organic pollutants to carbon dioxide and water. Because ozone is unstable, it is generally produced onsite in gas mixtures and is immediately introduced to water using gas/liquid type reactors (e.g. bubble columns). The ozone reactions are hence of the type gas liquid reactions, which are complex to model since they involve both chemical reactions, which occur in the liquid phase, and mass transfer from the gas to the liquid phase. This study focuses on two aspects: mass transfer and chemical reactions in multicomponent systems. The mass transfer parameters were determined by experiments under different conditions and the chemical reactions were studied using single component and multicomponent systems. Two models obtained from the literature were adapted to the systems used in this study.
Mass transfer parameters in the semi-batch reactor were determined using oxygen and ozone at different flow rates in the presence and absence of t-butanol. t-Butanol is used as a radical scavenger in ozonation studies and it has been found to affect the gas¿liquid mass transfer rates. An experimental study was carried out to investigate the effects of t-butanol concentrations on the physical properties of aqueous solutions, including surface tension and viscosity. It was found that t-butanol reduced both properties by 4% for surface tension and by a surprising 30% for viscosity. These reductions in the solution physical properties were correlated to enhancement in the mass transfer coefficient, kL. The mass transfer coefficient increased by about 60% for oxygen and by almost 50% for ozone. The hydrodynamic behaviour of the system used in this work was characterised by a homogeneous bubbling regime. It was also found that the gas holdup was significantly enhanced by the addition of t-butanol. Moreover, the addition of t-butanol was found to significantly reduce the size of gas bubbles, leading to enhancement in the volumetric mass transfer coefficient, kLa.
The multicomponent ozonation was studied with two systems, slow reactions when alcohols were used and fast reactions when endocrine disrupting compounds were used.
ii
These experiments were simulated by mathematical models. The alcohols were selected depending on their volatilization at different initial concentrations and different gas flow rates. The degradation of n-propanol as a single compound was studied at the lowest flow rate of 200 mL/min. It was found that the degradation of n-propanol reached almost 60% within 4 hours. The degradation of the mixture was enhanced with an increase in the number of components in the mixture. It was found that the degradation of the mixture as three compounds reached almost 80% within four hours while the mixture as two compounds reached almost 70%. The effect of pH was studied and it was found that an increase in pH showed slight increase in the reaction. Fast reactions were also investigated by reacting endocrine disrupting chemicals with ozone. The ozone reactions with the endocrine disrupters were studied at different gas flow rates, initial concentrations, ozone concentrations and pH. The degradation of 17¿-estradiol (E2) as a single compound was the fastest, reaching about 90% removal in almost 5 minutes. However estrone (E1) degradation was the lowest reaching about 70% removal at the same time. The degradation of mixtures of the endocrine disruptors was found to proceed to lower percentages than individual components under the same conditions. During the multicomponent ozonation of the endocrine disruptors, it was found that 17¿-estradiol (E2) converted to estrone (E1) at the beginning of the reaction.
A MATLAB code was developed to predict the ozone water reactions for single component and multicomponent systems. Two models were used to simulate the experimental results for single component and multicomponent systems. In the case of single component system, good simulation of both reactions (slow and fast) by model 1 was obtained. However, model 2 gave good agreement with experimental results only in the case of fast reactions. In addition, model 1 was applied for multicomponent reactions (both cases of slow and fast reaction). In the multicomponent reactions by model 1, good agreement with the experimental results was also obtained for both cases of slow and fast reactions.<br>Ministry of Higher Education in Libya and the Libyan Cultural Centre and Educational Bureau in London.
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Derdar, Mawaheb M. Zarok. "Experimental and kinetic modelling of multicomponent gas/liquid ozone reactions in aqueous phase : experimental investigation and Matlab modelling of the ozone mass transfer and multicomponent chemical reactions in a well agitated semi-batch gas/liquid reactor." Thesis, University of Bradford, 2010. http://hdl.handle.net/10454/4872.
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Due to the ever increasing concerns about pollutants and contaminants found in water, new treatment technologies have been developed. Ozonation is one of such technologies. It has been widely applied in the treatment of pollutants in water and wastewater treatment processes. Ozone has many applications such as oxidation of organic components, mineral matter, inactivation of viruses, cysts, bacteria, removal of trace pollutants like pesticides and solvents, and removal of tastes and odours. Ozone is the strongest conventional oxidant that can result in complete mineralisation of the organic pollutants to carbon dioxide and water. Because ozone is unstable, it is generally produced onsite in gas mixtures and is immediately introduced to water using gas/liquid type reactors (e.g. bubble columns). The ozone reactions are hence of the type gas liquid reactions, which are complex to model since they involve both chemical reactions, which occur in the liquid phase, and mass transfer from the gas to the liquid phase. This study focuses on two aspects: mass transfer and chemical reactions in multicomponent systems. The mass transfer parameters were determined by experiments under different conditions and the chemical reactions were studied using single component and multicomponent systems. Two models obtained from the literature were adapted to the systems used in this study. Mass transfer parameters in the semi-batch reactor were determined using oxygen and ozone at different flow rates in the presence and absence of t-butanol. t-Butanol is used as a radical scavenger in ozonation studies and it has been found to affect the gas-liquid mass transfer rates. An experimental study was carried out to investigate the effects of t-butanol concentrations on the physical properties of aqueous solutions, including surface tension and viscosity. It was found that t-butanol reduced both properties by 4% for surface tension and by a surprising 30% for viscosity. These reductions in the solution physical properties were correlated to enhancement in the mass transfer coefficient, kL. The mass transfer coefficient increased by about 60% for oxygen and by almost 50% for ozone. The hydrodynamic behaviour of the system used in this work was characterised by a homogeneous bubbling regime. It was also found that the gas holdup was significantly enhanced by the addition of t-butanol. Moreover, the addition of t-butanol was found to significantly reduce the size of gas bubbles, leading to enhancement in the volumetric mass transfer coefficient, kLa. The multicomponent ozonation was studied with two systems, slow reactions when alcohols were used and fast reactions when endocrine disrupting compounds were used. ii These experiments were simulated by mathematical models. The alcohols were selected depending on their volatilization at different initial concentrations and different gas flow rates. The degradation of n-propanol as a single compound was studied at the lowest flow rate of 200 mL/min. It was found that the degradation of n-propanol reached almost 60% within 4 hours. The degradation of the mixture was enhanced with an increase in the number of components in the mixture. It was found that the degradation of the mixture as three compounds reached almost 80% within four hours while the mixture as two compounds reached almost 70%. The effect of pH was studied and it was found that an increase in pH showed slight increase in the reaction. Fast reactions were also investigated by reacting endocrine disrupting chemicals with ozone. The ozone reactions with the endocrine disrupters were studied at different gas flow rates, initial concentrations, ozone concentrations and pH. The degradation of 17β-estradiol (E2) as a single compound was the fastest, reaching about 90% removal in almost 5 minutes. However estrone (E1) degradation was the lowest reaching about 70% removal at the same time. The degradation of mixtures of the endocrine disruptors was found to proceed to lower percentages than individual components under the same conditions. During the multicomponent ozonation of the endocrine disruptors, it was found that 17β-estradiol (E2) converted to estrone (E1) at the beginning of the reaction. A MATLAB code was developed to predict the ozone water reactions for single component and multicomponent systems. Two models were used to simulate the experimental results for single component and multicomponent systems. In the case of single component system, good simulation of both reactions (slow and fast) by model 1 was obtained. However, model 2 gave good agreement with experimental results only in the case of fast reactions. In addition, model 1 was applied for multicomponent reactions (both cases of slow and fast reaction). In the multicomponent reactions by model 1, good agreement with the experimental results was also obtained for both cases of slow and fast reactions.
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MONCADA, QUINTERO CARMEN WILLIANA. "Ceramic open cell foams as catalytic support for endothermic and exothermic reactions: Focus on lean methane combustion." Doctoral thesis, Politecnico di Torino, 2021. http://hdl.handle.net/11583/2929756.
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Brunet, Robert A. H. "Silent discharge water treatment, mass transfer and reaction rates." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp03/MQ39805.pdf.
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Miller, Sylvia C. "Application of proton transfer reaction mass spectrometry to analytical science." Thesis, Open University, 2014. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.664473.
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This work concerns a proton transfer reaction time-of-flight mass spectrometer, PTR-TOF-MS, a bespoke model manufactured by Kore Technology Ltd. for Smiths Detection. This instrument achieves 'soft' ionization of volatile 'organic compounds (VOCs) by proton transfer from protonated water vapour in a reaction chamber at 1 mbar (= 100 Pa). The resulting ions are separated by mass in a field-free time-of-flight tube prior to detection by a multi-channel plate. The instrument was modified to facilitate direct determination of the electric field in the reaction chamber. Sensitivity measurements determined a value of 4-6 counts per second per parts per billion by volume (ncps ppbv·1 ) normalised to 106 H30+. The calibration gas mixture used in this investigation consisted of 14 compounds, (alkylbenzenes and chlorobenzenes) spanning an mlz range of 78 to 180. Each of these was separately investigated over EIN = 90 to 245 Td to establish fragmentation behaviour and possible interfering contributions. For example, several of the alkylbenzenes fragmented to product ions occurring at mlz 79, the same value as that of protonated benzene. Most of this occurred at the higher EIN values with ethylbenzene a notable exception. The isobaric compounds ethyl benzene and the xylenes exhibit very different fragmentation patterns so enabling differentiation of these two compounds. However, it is not possible to distinguish the individual xylene isomers using this method. Benchmarking was continued using the hexenol compounds cis-3-, cis-2-, trans-3- and trans-2- hexen-I-ols. This work demonstrated that the same four product ions are seen for all of the hexenol isomers at mlz 39 (C3H/), 41 (C3H/), 55 (C4H/) and 83 (C6Hl1+) when reacted with H30+ in a PTR-TOF-MS. A characteristic peak at mlz 99 was seen in trans-2-hexen-1-01 and cis- 2-hexen-1-01 at low EINvalues « 140 Td) when the protonated parent ion, mlz 101, is absent. In trans-3-hexen-l-ol and cis-3-hexen-1-01 the MW ion at mlz 101 is seen at these lower EIN values but there is no product ion at mlz 99. This suggests a possible method for distinguishing between the 2- and 3-hexenols. It may also be possible to further identify the individual isomers from the differences in the percentage yield of these product ions.
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Tervasmäki, P. (Petri). "Reaction and mass transfer kinetics in multiphase bioreactors:experimental and modelling studies." Doctoral thesis, Oulun yliopisto, 2018. http://urn.fi/urn:isbn:9789526220390.
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Abstract In the sugar platform of biorefining, the complex polymeric structure of lignocellulose biomass is degraded into sugars, which are utilized by microbial cells in the further processing steps. The reaction steps in both biomass degradation and microbial fermentation processes involve multiphase reactions in which mass transfer and reaction kinetics often play a key role. The aim of this thesis is to characterize the effect of these conditions on enzymatic hydrolysis of cellulose and utilization of sugars by aerobic microbes. These types of liquid-solid (cellulose hydrolysis) and liquid-gas (microbial cultivation) systems are typically very demanding on the reactors that are used in the process. By the fed-batch process utilized in this work, sufficient mixing in enzymatic hydrolysis of cellulose is achieved even with high final substrate concentration. One of the main outcomes of this work is the kinetic model that concentrates on the kinetics of fed-batch process by discretizing the substrate into subpopulations. By using this approach, the model parameters were identified in an adequate manner, and the poorly identified parameters could be sorted out. Parameter identifiability has been an issue in previous models for enzymatic hydrolysis of cellulose. Based on the experiments and modelling studies, it can be concluded that the enzymes remain intact for time scales relevant for the hydrolysis process. Thus, the decrease in the hydrolysis rate found in many literature studies is probably mostly due to substrate-enzyme interactions rather than denaturation of the enzyme. In aerobic cell cultivations, the mixing and mass transfer conditions are often more critical for the process performance. In this work, we studied the performance and suitability of alternative reactor types to be used in aerobic cell cultivations and obtained some promising results. In addition, the thesis presents a modelling approach to study the effect of process conditions on metabolism and growth rate of Pichia pastoris yeast. The model combines a kinetic model for yeast growth and a model for the mixing and mass transfer conditions in stirred tank reactor<br>Tiivistelmä Biojalostuksen sokerialustassa lignoselluloosapohjaisen biomassan monimutkaista polymeerirakennetta muokataan ja sieltä vapautetaan monomeerisia sokereita, joita voidaan edelleen hyödyntää jatkojalostuksessa. Monet jatkojalostusprosessit käyttävät mikrobeja, joiden aineenvaihdunnassa sokereita voidaan jalostaa arvokkaammiksi tuotteiksi ns. fermentointiprosesseissa. Tämän väitöstyön tarkoitus on tutkia reaktio- ja aineensiirtokinetiikan vaikutusta selluloosan entsymaattiseen hydrolyysiin ja aerobisiin mikrobifermentointeihin. Näistä ensimmäinen on neste-kiintoainesysteemi ja jälkimmäinen neste-kaasusysteemi, ja tällaiset prosessit asettavat tyypillisesti merkittäviä vaatimuksia niissä käytettäville reaktoreille. Tässä työssä hyödynnettiin kiinteän raaka-aineen vähittäistä syöttöä (ns. fed-batch prosessi) selluloosan hydrolyysissä, jolloin sekoitus voidaan pitää riittävänä suurillakin kiintoainemäärillä. Työn merkittävin tuotos on kineettinen malli, jossa hyödynnetään fed-batch prosessia ja koedataa osittamalla mallinnusyhtälöt raaka-aineen syöttöajan perusteella. Tällä tavalla mallin parametrit saatiin identifioitua kohtuullisella tarkkuudella sekä eriteltyä huonosti identifioituneet parametrit. Mallin parametrien identifiointi on ollut ongelmallista monissa vastaavan tyyppisissä malleissa aiemmin. Kokeiden ja mallinnustulosten perusteella voidaan sanoa, että hydrolyysissä käytettävät entsyymit pysyvät aktiivisina prosessin aikana, ja usein todettu hydrolyysin hidastuminen johtuu ennemmin kiinteän kuidun ja entsyymien vuorovaikutuksen muutoksista kuin entsyymin denaturoitumisesta. Aerobisiin mikrobikasvatuksiin liittyen tässä työssä tutkittiin vaihtoehtoisten reaktorityyppien hyödyntämistä, joista saatiin myös lupaavia tuloksia. Lisäksi työssä kehitettiin mallinnustyökaluja, joilla voidaan tutkia prosessiolosuhteiden vaikutusta Pichia pastoris –hiivan metaboliaan ja kasvunopeuteen. Mallissa yhdistetään hiivan kasvun kineettinen malli sekä reaktoriolosuhteiden mallinnus
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Serbetcioglu, Serpil. "Mass transfer and catalytic reaction in a three-phase monolith reactor." Thesis, University of Bath, 1993. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.332665.
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Panda, Kishora Kumar. "Ozone mass transfer and reaction in In situ and stirred tank reactors /." Search for this dissertation online, 2005. http://wwwlib.umi.com/cr/ksu/main.
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Ramström, Eva. "Mass transfer and slag-metal reaction in ladle refining : a CFD approach." Licentiate thesis, Stockholm : KTH, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-11864.
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<p> </p><p>In order to optimise the ladle treatment mass transfer modelling of aluminium addition and homogenisation time was carried out. It was stressed that incorporating slag-metal reactions into the mass transfer modelling strongly would enhance the reliability and amount of information to be analyzed from the CFD calculations.</p><p> </p><p>In the present work, a thermodynamic model taking all the involved slag metal reactions into consideration was incorporated into a 2-D fluid flow model of an argon stirred ladle. Both thermodynamic constraints and mass balance were considered. The activities of the oxide components in the slag phase were described using the thermodynamic model by Björkvall and the liquid metal using the dilute solution model. Desulphurization was simulated using the sulphide capacity model developed by KTH group. A 2-D fluid flow model considering the slag, steel and argon phases was adopted.</p><p> </p><p>The model predictions were compared with industrial data and the agreement was found quite satisfactory. The promising model calculation would encourage new CFD simulation of 3-D along this direction.</p><p> </p>
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Rogers, Todd Michael. "Application of proton transfer reaction mass spectrometry to measure hydrocarbon emissions in engine exhaust." Diss., Montana State University, 2007. http://etd.lib.montana.edu/etd/2007/rogers/RogersT0807.pdf.
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Moore, Stephen Russell. "Mass transfer to thin liquid films on rotating surfaces, with and without chemical reaction." Thesis, University of Newcastle Upon Tyne, 1986. http://hdl.handle.net/10443/329.
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This investigation was concerned with the ability of perforated discs to act as the active mass transfer surface in rotary contact devices. Of particular interest were discs constructed of a woven stainless steel mesh. This material had a high fractional free area and an irregular surface, which is desirable if interfacial turbulence is to be promoted. The characteristics of three grades of mesh were compared with those of a plate perforated with punched holes and a smooth plane disc. A hydrodynamic study indicated that a stable film could be maintained on these flexible materials at speeds in excess of 200 RPM. However it was also demonstrated that at higher speeds dry areas tended to form around the periphary. The mass transfer performance was analysed in a specially designed rotary test rig using a carbon dioxide/water system. These experiments indicated that high transfer rates are attainable provided that operation is restricted to conditions where film breakdown does not occur. At 1500 RPM flowrates in excess of 200 cm 3 /sec must be utilised. The same apparatus was adapted so that the enhancement due to a chemical reaction in the liquid phase could be determined. Aqueous solutions of diethanolamine were used in these experiments. The results were compared with predictions based upon a penetration type theory. The results of the investigation were applied to the design of a scrubber for an underwater closed—cycle nitro diesel engine and conclusions as to the relative merits of physical and chemical systems made.
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Cenci, Steven Michael. "Acoustic agitation of dense carbon dioxide/water mixtures : emulsification, mass transfer, and reaction engineering." Thesis, University of Birmingham, 2014. http://etheses.bham.ac.uk//id/eprint/5381/.
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Acoustic agitation of a carbon dioxide/water mixture in a 1 dm3 cylindrical, high-pressure reactor led to the simultaneous formation of carbon dioxide/water (C/W) and water/carbon dioxide (W/C) emulsions, with the dispersed phase occupying up to 10% of the volume. These emulsions were stable for several minutes. Inclusion of 1% of the non-ionic surfactant Tween 80 led to the generation of C/W emulsions which were stable for over 1 hour after ceasing sonication, in which all of the carbon dioxide present in the system comprised the dispersed phase. The mixing capacity of pulsed ultrasound was assessed by studying the mass transfer of benzaldehyde across the carbon dioxide/water interface, leading to determination of the system mixing time. A model for mass transfer with a fast chemical reaction, namely the hydrolysis of benzoyl chloride, was used to separate the mass transfer and kinetic effects, and to identify those reactions that would most significantly benefit from ultrasound-induced emulsification. For the first time, the Barbier synthesis was shown to occur in a carbon dioxide/water mixture as solvent, leading to moderate to high yields. Moreover, it was possible to recover the homoallylic alcohol product directly from the carbon dioxide phase in which it was preferentially partitioned.
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Miller, Jacob. "Modelling the Effect of Catalysis on Membrane Contactor Mass Transfer Coefficients for Carbon Dioxide Absorption Systems." University of Cincinnati / OhioLINK, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1627662756315225.
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Krishnamurthy, Nagendra. "A Study of Heat and Mass Transfer in Porous Sorbent Particles." Diss., Virginia Tech, 2014. http://hdl.handle.net/10919/64412.
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This dissertation presents a detailed account of the study undertaken on the subject of heat and mass transfer phenomena in porous media. The current work specifically targets the general reaction-diffusion systems arising in separation processes using porous sorbent particles. These particles are comprised of pore channels spanning length scales over almost three orders of magnitude while involving a variety of physical processes such as mass diffusion, heat transfer and surface adsorption-desorption. A novel methodology is proposed in this work that combines models that account for the multi-scale and multi-physics phenomena involved. Pore-resolving DNS calculations using an immersed boundary method (IBM) framework are used to simulate the macro-scale physics while the phenomena at smaller scales are modeled using a sub-pore modeling technique.
The IBM scheme developed as part of this work is applicable to complex geometries on curvilinear grids, while also being very efficient, consuming less than 1% of the total simulation time per time-step. A new method of implementing the conjugate heat transfer (CHT) boundary condition is proposed which is a direct extension of the method used for other boundary conditions and does not involve any complex interpolations like previous CHT implementations using IBM. Detailed code verification and validation studies are carried out to demonstrate the accuracy of the developed method.
The developed IBM scheme is used in conjunction with a stochastic reconstruction procedure based on simulated annealing. The developed framework is tested in a two-dimensional channel with two types of porous sections - one created using a random assembly of square blocks and another using the stochastic reconstruction procedure. Numerous simulations are performed to demonstrate the capability of the developed framework. The computed pressure drops across the porous section are compared with predictions from the Darcy-Forchheimer equation for media composed of different structure sizes. The developed methodology is also applied to CO2 diffusion studies in porous spherical particles of varying porosities.
For the pore channels that are unresolved by the IBM framework, a sub-pore modeling methodology developed as part of this work which solves a one-dimensional unsteady diffusion equation in a hierarchy of scales represented by a fractal-type geometry. The model includes surface adsorption-desorption, and heat generation and absorption. It is established that the current framework is useful and necessary for reaction-diffusion problems in which the adsorption time scales are very small (diffusion-limited) or comparable to the diffusion time scales. Lastly, parametric studies are conducted for a set of diffusion-limited problems to showcase the powerful capability of the developed methodology.<br>Ph. D.
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Neogi, Swati. "Modeling high viscosity melt phase polycondensation reactors using direct inclusion of experimental mixing data." Ohio : Ohio University, 1992. http://www.ohiolink.edu/etd/view.cgi?ohiou1173754996.
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Misztal, Pawel K. "Concentrations and fluxes of atmospheric biogenic volatile organic compounds by proton transfer reaction mass spectrometry." Thesis, University of Edinburgh, 2010. http://hdl.handle.net/1842/4674.
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There are few published direct measurements of the atmosphere-surface exchange of volatile organic compounds (VOCs), particularly for biogenic VOCs (BVOCs). Global modelling of atmospheric chemistry and transport of BVOCs has large uncertainties due to the very small number of measurements in tropical regions, which are responsible for half the global BVOC emissions. This thesis presents direct measurements of concentrations and ecosystem fluxes of BVOCs in different regions (Tropics, Mediterranean) using the approach of virtual disjunct eddy covariance (vDEC) combined with proton transfer reaction mass spectrometry (PTR-MS) – a real-time BVOC sensor. The field measurements also included methodological developments of the vDEC/PTR-MS approach, which will be of value to the wider flux measurement community. A novel approach to determining the lag time between the vertical wind measurement and the air concentration measurement has been developed that will greatly reduce the uncertainty in the derived flux measurements. In the laboratory, the selectivity of PTR-MS was investigated by designing an alternating drift-voltage mode (AD-PTR-MS) to discriminate between structural isomers detected at the same m/z channel, with monoterpenes used as model compounds. The results of the measurements, particularly from the rainforest and oil palm plantations in Borneo, are novel and therefore provide important experimental constraints on models of atmospheric emissions, chemistry and transport. For example, although parameters which work reasonably well can be derived for model algorithms for the emission of isoprene from the rainforest, their performance over oil palms was less good, because of circadian controls of emissions from oil palms. However, the larger problem is the measured basal emission rates (BERs) which are significantly smaller than those used by default in the global MEGAN model. Another novel finding was the high deposition velocities of MVK and MACR (isoprene first order oxidation products) which at the oil palm plantation commonly exceeded 1 cm s-1; this result has implications for atmospheric modelling. The successful field results relied on significant developments in software for data acquisition and processing, and operational optimisation of the PTR-MS instruments in the extreme humidity encountered during the fieldwork in Borneo.
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Szwec, Stuart V. "Transfer reaction studies of medium mass nuclei-single-particle occupancies and neutrinoless double beta decay." Thesis, University of Manchester, 2018. https://www.research.manchester.ac.uk/portal/en/theses/transfer-reaction-studies-of-medium-mass-nuclei--singleparticle-occupancies-and-neutrinoless-double-beta-decay(6120c9fe-c85d-42fd-908f-e07e07cccd50).html.
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Two separate investigations are presented, both linked by a common interest in the occupancy of the valence neutron orbitals and their relation to nuclear structure studies. A study of the change in neutron occupancy in the 0Î1⁄22Î2 decay of 136 Xe â 136 Ba has been performed. The neutron occupancies of 136 Ba have been probed us- ing the (p,d) and ( 3 He,α) neutron-removal reactions and the (d,p) and (α, 3 He) neutron-addition reactions, performed at the Institut Physique Nucl Ìeaire, Orsay. The same reactions have been performed on 134 Ba as an additional consistency check. Spectroscopic factors were extracted through a DWBA analysis and the valence orbital occupancies were extracted using the Macfarlane and French sum rules. The change in neutron occupancy that occurs during 0Î1⁄22Î2 decay was then determined and compared to those calculated by using the interacting shell model and the interacting boson model. The comparison showed that while the various models were able to qualitatively describe the change in occupancy, quantitatively there are significant differences between the models. These are the same models that are used to determine the nuclear matrix elements used in determining the rate of 0Î1⁄22Î2 decay. An additional systematic study of the valence neutron occupancies on the seven even stable tin isotopes is presented. The occupancies were probed in two sets of experiments. The first measurement used the low Q-value (p,d) and (d,p) reactions performed at the Maier-Leibnitz-Laboratory, Munich, to extract spec- troscopic information for low-j orbitals. The second measurement used the high Q-value ( 3 He,α) and (α, 3 He) reactions at the Institut Physique Nucl Ìeaire, Orsay to extract spectroscopic information for high-j states. Absolute cross sections were determined and the amount transferred angular momenta was identified by comparison of angular distributions to those calculated using a DWBA analysis. The spectroscopic factors were used in conjunction with the Macfarlane-French sum rules to determine the valence neutron occupancies. These measurements not only qualitatively test the robustness of sum rules in transfer reactions but also provide information about the neutron occupancy of 116 Sn and 124 Sn, two nu- clei of relevance to 0Î1⁄22Î2 decay. The measured occupancies of these two isotopes were compared to those obtained from recent theoretical calculations.
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Brown, Philip Andrew. "Investigations of proton transfer reaction mass spectrometry for applications in organophosphate detection and breath analysis." Thesis, University of Birmingham, 2012. http://etheses.bham.ac.uk//id/eprint/3839/.
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The reduced electric field dependence of a series of twelve saturated alcohols was investigated with a proton transfer reaction mass spectrometer, PTR-MS. Fragmentation reactions were observed for all but one compound and the dependence of this fragmentation was recorded as a function of reduced electric field. A number of common fragment ions were observed corresponding to carbocations. Effects on the branching ratios from the hollow cathode emission current were also observed and investigated. The reaction of dimethyl methylphosphonate, DMMP in a PTR-MS was studied, along with further chemical weapon simulants. The reaction with DMMP was investigated to explain a product ion at m/z 111. The PTR-MS has been used to demonstrate the possibilities of breath analysis in the diagnosis of liver disease. A promising marker may be limonene, observed on the breath of patients suffering from encephalopathy. Further work would be needed to understand the source of this compound before being used for diagnostic purposes. Data are also reported relevant to the repeatability of a breath sample. The sampling repeatability was calculated for isoprene, acetone, methanol, ethanol and monoterpene. The repeatability for each compound was found to be affected by the intensity of the measured ion and the compound’s solubility.
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Lourenco, Celia Maria Farinha. "Applications of proton transfer reaction and selected ion flow tube mass spectrometry in health monitoring." Thesis, Open University, 2017. http://oro.open.ac.uk/49148/.
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This thesis investigates the use of Volatile Organic Compounds (VOCs) in disease diagnosis and monitoring. VOCs may be found in the human body, in exhaled breath, faecal matter, urine, and skin. Analysis of the volatile profile produced in the human body can provide an indicator of metabolic status, allowing the screening and monitoring of different diseases and conditions, non-invasively and painlessly. In this thesis a range of highly sensitive analytical techniques have been adopted to measure such VOCs and demonstrate that such monitoring may be used as a disease diagnostic. For example breath samples may be analysed and calibrated against gas-phase standards prepared under physiologically representative concentrations as a tool for non-invasive disease monitoring, e.g. type 2 diabetes. Detailed faecal headspace analyses of two different mouse models of type 2 diabetes (Cushing´s mice and Afmid) were made. The mouse model of Cushing’s syndrome develop excessive circulating glucocorticoid concentrations, which are associated with obesity, hyperglycaemia and insulin resistance. The Afmid knockout mice suffer inactivation of Afmid genes, which in part regulates many functions including pancreatic secretion. These mice show impaired glucose tolerance. The gut microbiota of diabetic mice appear to have a different composition when compared to wild-type littermates, i.e. significantly increased levels of short-chain fatty acids (SCFAs), ketones, alcohols and aldehydes were found in the faecal headspace of diabetic mice, and a possible link between gut microbiota and type 2 diabetes is demonstrated. The use of VOCs as a screening tool of colorectal cancer was also explored. The current screening tools show lack of sensitivity and specificity for the screening of the disease. The volatile faecal profile of patients with colorectal cancer was investigated, and sulphide compounds, including hydrogen sulphide (H2S) are shown to have potential as biomarkers for screening of colorectal cancer.
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Nishikawa, Kei. "Mass transfer of Li[+] ion accompanied by charging and discharging reaction of Li battery electrode." Kyoto University, 2006. http://hdl.handle.net/2433/135558.
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Kyoto University (京都大学)<br>0048<br>新制・課程博士<br>博士(エネルギー科学)<br>甲第12623号<br>エネ博第141号<br>新制||エネ||34(附属図書館)<br>UT51-2006-S631<br>京都大学大学院エネルギー科学研究科エネルギー基礎科学専攻<br>(主査)教授 尾形 幸生, 教授 八尾 健, 教授 福中 康博<br>学位規則第4条第1項該当
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Krieger, Waldemar [Verfasser]. "Local Measurement of Gas-Liquid Mass Transfer with Chemical Reaction in Coiled Capillaries / Waldemar Krieger." München : Verlag Dr. Hut, 2020. http://d-nb.info/1219321435/34.
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Töröková, Lucie. "Studium chemických procesů v atmosféře Titanu iniciovaných výbojem v elektrodové konfiguraci klouzavého obloukového výboje." Doctoral thesis, Vysoké učení technické v Brně. Fakulta chemická, 2015. http://www.nusl.cz/ntk/nusl-234529.
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The aim of this work is the study of plasma processes and the synthesis of organic compounds due to electric discharge generated in gas mixture corresponding to the composition of the atmosphere of Saturn's largest moon Titan. This study focuses on the mimic of Titan's atmosphere at atmospheric pressure and ambient laboratory temperature. The chemical composition of Titan's atmosphere is very similar to atmosphere of prehistoric Earth. Many articles have been published with theoretical model-research, and laboratory experiments are the pursuit of their interconnection. The main aim of thesis is the identification of synthesized gaseous organic, amino, imino and cyano compounds by use to various analytical methods such as the PTR-MS, FTIR and GC-MS. The OES and electric measurements were applied to the determination of selected electric discharge parameters. The gaseous products and radicals formed in an atmospheric discharge fed by different mixtures of N2:CH4 (0,5 up to 5 % of CH4) operated in a flowing regime at the total gas mixture flows from 50 to 200 sccm at different discharge currents from 15 up to 40 mA were determined. A part of experiments was carried out with admixtures of CO2 and hydrogen. This first part of results has been obtained using OES in dependence on the gas mixture composition and supplied power. The bands of the nitrogen second positive and the first negative systems, CN violet system and Swan system of C2 were recorded. Besides them, atomic lines H, H, and C (in the second order) were also observed. These spectra allowed calculation of rotational and vibrational temperatures. FTIR in situ analysis of the gaseous products showed presence of various nitrile compounds and hydrocarbons in all experiments. The HCN, C2H2, NH3 were the main products generated in our system. The dependences of their concentrations on various experimental parameters were measured. The other part of this work was devoted to estimate the influence of CO2 traces addition on the reactivity in the gaseous mixtures mentioned above. Besides the main products mentioned above, CO2 and CO were detected and also some more complicated oxygen molecules has been confirmed but not estimated because of FTIR spectra complexity. In the case of hydrogen traces addition into the reaction gas mixture, no other compounds were determined. Impurities of CO2 as well as hydrogen have a great positive influence on the production efficiency of the major generated compounds at all conditions. The more detailed gaseous products analyses were carried out using the in situ PTR-MS. A huge number of different molecular structures containing nitrile groups (–CN), amino groups (–NH2, –NH–, –N CH3CN > C2H5CN. Besides them, many other hydrocarbons and nitriles were detected. Presence of all compounds was studi
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Ross, Charles William. "Gas phase ion - molecule reactions studied by Fourier transform ion cyclotron resonance mass spectrometry /." The Ohio State University, 1993. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487846885778077.
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Yin, Winnie Weixin. "Fourier transform ion cyclotron resonance mass spectrometric study of gas-phase ion-molecule reactions /." The Ohio State University, 1993. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487847309051562.
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Sookhak, Lari Kaveh. "Mass transfer of solutes in turbulent wall bounded flows reacting with the conduit surface." Thesis, Imperial College London, 2011. http://hdl.handle.net/10044/1/7129.
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This thesis focuses on the decay of chlorine in pipes of drinking water distribution networks due to wall and bulk demand. Accurate prediction of chlorine decay is important, as both chlorine concentrations which are too low and too high pose serious health risks, the former due to pathogen formation and the latter due to the formation of disinfection by-products. Water quality models used for the prediction of chlorine decay make use of parameterisations for the wall demand in the form of Sherwood number Sh correlations, which couple the wall mass flux to a Reynolds number Re, Schmidt number Sc and wall roughness. These correlations are subject to significant uncertainty, particularly for turbulent flows. A combined analytical and numerical approach is taken to study in detail the interaction between flow, turbulence and mass transport, with the aim of improving the understanding and accuracy of wall demand parameterisations for chlorine. Simulations of the chlorine decay in an axisymmetric pipe with hydraulically smooth walls were performed for Re = 104 to 106 and Sc = 1000 using Reynolds averaged conservation equations. These values are typical for chlorine transport in distribution networks. The simulations confirmed that the assumptions made in water quality models for chlorine wall demand are valid. Asymptotic solutions for high Sc solutes were developed which are applicable both to linear and nonlinear wall reactions. Results showed that the Sh correlation is independent of the reaction type. For rough walls, the two main wall demand parameterisations are mutually inconsistent: one is valid for low and the other for high wall demand coefficients only. Numerical simulation of flow and high Sc mass transport over a dtype rough surface at Re = 2.5×105 showed that the inconsistency between the two parameterisations was caused by the geometry. For low wall demand coefficients, the existence of roughness elements causes higher wall demand than for a smooth wall. However, at high wall demand coefficients the maximum wall demand achievable in the cavities was much smaller than for the crests. Hence, the effective surface area and therefore the wall demand became lower than for a smooth wall. A parameterisation was developed which reproduced the solute mass decay over the entire range of wall demand coefficients. Most of the solutions and parameterisations developed in this thesis are on the same level of description as water quality models. The findings of this thesis can be used as supportive evidence for the validity of assumptions made for water quality models, and to inform how processes should be modelled when these assumptions are violated.
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Onea, Alexandru Aurelian. "Numerical simulation of mass transfer with and without first order chemical reaction in two-fluid flows." Karlsruhe FZKA, 2006. http://bibliothek.fzk.de/zb/berichte/FZKA7274.pdf.
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Onea, Alexandru Aurelian. "Numerical simulation of mass transfer with and without first order chemical reaction in two-fluid flows." Karlsruhe : FZKA, 2007. http://nbn-resolving.de/urn:nbn:de:0005-072749.
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González-Méndez, Ramón. "Development and applications of proton transfer reaction-mass spectrometry for homeland security : trace detection of explosives." Thesis, University of Birmingham, 2017. http://etheses.bham.ac.uk//id/eprint/7538/.
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This thesis investigates the challenging task of sensitive and selective trace detection of explosive compounds by means of proton transfer reaction mass spectrometry (PTR-MS). In order to address this, new analytical strategies and hardware improvements, leading to new methodologies and analytical tools, have been developed and tested. These are, in order of the Chapters presented in this Thesis, the switching of reagent ions, the implementation of a novel thermal desorption unit, and the use of an ion funnel drift tube or fast reduced electric field switching to modify the ion chemistry. In addition to these, a more fundamental study has been undertaken to investigate the reactions of picric acid with a number of different reagent ions. The novel approaches described in this thesis have improved the PTR-MS technique by making it more versatile in terms of its analytical performance, namely providing assignment of chemical compounds with high confidence. These techniques are going to be employed in the new generation of PTR-MS instruments being developed by KORE Technology Ltd. Although demonstrated for Homeland Security in this thesis, the developments made can be utilised for improved selectivity in areas such as atmospheric chemistry, and in the environmental, food and health sciences.
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Blenkhorn, Daniel John. "Novel approaches to the measurement of complex atmospheric VOC mixtures using proton transfer reaction mass spectrometry." Thesis, University of Birmingham, 2019. http://etheses.bham.ac.uk//id/eprint/8695/.
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Proton Transfer Reaction - Mass Spectrometry (PTR-MS) is a soft chemical ionisation mass spectrometry technique frequently applied to measurement of volatile organic compound (VOC) abundance. The overarching aim of this thesis is to improve the quantification of compounds that have proved difficult or even impossible to separate or to quantify, through advanced understanding of the detection and ionisation mechanisms and developments in the instrumental design and operation of PTR-MS for deconvolution of mixtures. A new method for the preparation and use of diffusion tube methods as gas standards is reported. Detailed investigation of the ion-molecule reactions with chloroalkanes, chloroalkenes and other atmospherically important molecules, such as isoprene / 2-methyl-3-buten-2-ol, benzene / ethylbenzene / o,m,p-xylene and methyl vinyl ketone / methacrolein were undertaken to determine the ion- molecule reaction mechanisms, allowing quantification of isomeric species through understanding of the reaction products and novel approaches to the switching of the reduced electric field strength (E/n). The modification of instrumental parameters of PTR-MS were investigated further for the quantification of semi volatile compounds (SVOCs) and more specifically, polycyclic aromatic hydrocarbons (PAHs). Use of a radio frequency (RF) ion funnel and high temperature instrumentation allowed for sub nanogram limits of detection for many PAHs, including Benzo[a]pyrene.
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Venkata, Padma Priya. "Computational modeling of heat and mass transfer in planar SOFC effects of volatile species/oxidant mass flow rate and electrochemical reaction rate /." Cincinnati, Ohio : University of Cincinnati, 2008. http://www.ohiolink.edu/etd/view.cgi?acc%5Fnum=ucin1205169104.
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Thesis (M.S.)--University of Cincinnati, 2008.<br>Committee/Advisors: Raj M Manglik PhD (Advisor), Milind A Jog PhD (Committee Member), Anastasios P Angelopoulos PhD (Committee Member) Title from electronic thesis title page (viewed April 23, 2008). Includes abstract. Keywords: SOFC, Solid oxide fuel cells, ASR, interconnect, CFD, heat and mass transfer, electrochemistry. Includes bibliographical references.