Dissertations / Theses on the topic 'Autocatalytic'
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Izzard, Michael. "Autocatalytic deposition of composite coatings." Thesis, Aston University, 1987. http://publications.aston.ac.uk/11907/.
Full textSullivan, Anne M. "Autocatalytic electroless gold deposition at low pH." Diss., Georgia Institute of Technology, 1995. http://hdl.handle.net/1853/10079.
Full textAgliari, Elena, Raffaella Burioni, Davide Cassi, and Franco M. Neri. "Autocatalytic reaction-diffusion processes in restricted geometries." Universitätsbibliothek Leipzig, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-192966.
Full textAgliari, Elena, Raffaella Burioni, Davide Cassi, and Franco M. Neri. "Autocatalytic reaction-diffusion processes in restricted geometries." Diffusion fundamentals 7 (2007) 1, S. 1-8, 2007. https://ul.qucosa.de/id/qucosa%3A14157.
Full textArsene, Simon. "Pre-evolutionary dynamics in autocatalytic RNA networks." Thesis, Sorbonne Paris Cité, 2018. http://www.theses.fr/2018USPCC156/document.
Full textNetworks of interdependent molecules are considered plausible candidates for initiating the transition from biology to chemistry. Though they have been intensively scrutinized theoretically, there is still no experimental evidence for confirming or denying their supposed crucial role in the origins of life. In particular, we are still lacking experimental proofs of any of the three ingredients usually presented as required for Darwinian evolution: heredity, variation and selection. A system that would possess the three while being coupled to some sort of encapsulated replication process would theoretically be able to undergo Darwinian evolution. As a matter of fact, this has been shown theoretically for Collectively Autocatalytic Sets (CAS) where each molecule of the set is catalytically formed by another member of the ensemble. Here we use the Azoarcus recombination ribozyme system to experimentally form structurally diverse CASs to explore their evolutionary properties. In this system, the ribozymes can catalyze the assembly of other ribozymes from smaller fragments, present in the food set. We first use a droplet microfluidics set-up coupled with next-generation sequencing to conduct a large scale study on thousands of Azoarcus CASs. We develop a perturbative approach to identify the important topological parameters that control variations in CASs as a result of environmental perturbations, here the addition of a new species. We then determine the small set of network features governing memory of the initial conditions in Azoarcus CAS, a pre-requisite for heredity, by using a computational model validated by experimental data. Finally, we demonstrate that Azoarcus CAS possess catabolic processes which make them robust to perturbations in the food set and thus more prebiotic relevant. These results provide evidence for the crucial role of RNA CASs in the origins of life and illustrate how the network structure can be tailored to obtain CASs with properties interesting from an evolutionary point of view, paving the way to an experimental demonstration of Darwinian evolution with a purely molecular system
Eden-Jones, Kym Denys. "Kinetic Monte Carlo simulations of autocatalytic protein aggregation." Thesis, University of Edinburgh, 2014. http://hdl.handle.net/1842/9365.
Full textEvans, Robert. "The effect of magnetic fields on autocatalytic chemical reactions." Thesis, University of Oxford, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.444929.
Full textQuaranta, Michela. "Mechanistic study of asymmetric amplification in the Soai autocatalytic reaction." Thesis, Imperial College London, 2010. http://hdl.handle.net/10044/1/6202.
Full textAl-Mannai, Muna. "Finite-difference methods for some non-linear reaction-diffusion systems in chemistry." Thesis, Brunel University, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.390219.
Full textBaer, Brian R. "Autocatalytic mechanism and functional consequences of covalent heme attachment in CYP4B1 /." Thesis, Connect to this title online; UW restricted, 2005. http://hdl.handle.net/1773/8176.
Full textSharma, Krishna. "Cation-controlled diastereo- and enantioselective synthesis of indolines : an autocatalytic process." Thesis, University of Oxford, 2014. http://ora.ox.ac.uk/objects/uuid:bfec8a97-7740-49f9-aa8f-5b97f632c21d.
Full textFusion, Joe. "The Role of Environmental Dynamics in the Emergence of Autocatalytic Networks." PDXScholar, 2015. https://pdxscholar.library.pdx.edu/open_access_etds/2458.
Full textMee, Trevor Richard. "Analysis of the proteolytic cleavage reaction of the tumour suppressor protein p53." Thesis, University of York, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.310987.
Full textBárcena, Menéndez Diego 1984. "A study on autocatalysis through synthetic biology. Exploration of spatiotemporal dynamics in the presence or absence of synthetic autocatalytic Hepatocyte Growth Factor signaling in mammalian cells." Doctoral thesis, Universitat Pompeu Fabra, 2016. http://hdl.handle.net/10803/523520.
Full textOne unanswered riddle in biology is how can mammalian cells organize to generate ordered patterns such as organs and living beings, in an ever changing environment. An underlying mathematical principle for the generation of order is given by feedback motifs. Here, I present two projects which are part of an effort to recreate stable ordered patterns in a cellular system through information encoded in DNA. In the first part, I present a receiver mammalian cell line which can accurately sense the diffusible Hepatocyte Growth Factor (HGF) through a transcriptional reporter. In the second part I reprogrammed this cell line so that it produces more HGF in response to HGF, in effect creating an autocatalytic positive feedback. In both cases, I have used spatiotemporal quantitative microscopy analysis to monitor the dynamic evolution of the cell lines in response to a HGF stimulus.
Mhatre, Bharat Suresh. "Super-enantiospecific Autocatalytic Decomposition of Tartaric Acid and Aspartic Acid on Cu Surfaces." Research Showcase @ CMU, 2013. http://repository.cmu.edu/dissertations/232.
Full textGlöde, Patric Karl [Verfasser], and Andreas [Akademischer Betreuer] Greven. "Dynamics of Genealogical Trees for Autocatalytic Branching Processes / Patric Karl Glöde. Betreuer: Andreas Greven." Erlangen : Universitätsbibliothek der Universität Erlangen-Nürnberg, 2013. http://d-nb.info/1033029912/34.
Full textGlöde, Patric [Verfasser], and Andreas [Akademischer Betreuer] Greven. "Dynamics of Genealogical Trees for Autocatalytic Branching Processes / Patric Karl Glöde. Betreuer: Andreas Greven." Erlangen : Universitätsbibliothek der Universität Erlangen-Nürnberg, 2013. http://nbn-resolving.de/urn:nbn:de:bvb:29-opus-45453.
Full textBlanken, Erika. "A NUMERICAL ANALYSIS APPROACH FOR ESTIMATING THE MINIMUM TRAVELING WAVE SPEED FOR AN AUTOCATALYTIC REACTION." Master's thesis, University of Central Florida, 2008. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/2389.
Full textM.S.
Department of Mathematics
Sciences
Mathematical Science MS
Eriksson, Mats. "Sliding wear performance of electroplated hard chromium and autocatalytic nickel-phosphorus coatings at elevated temperatures." Thesis, Karlstads universitet, Avdelningen för maskin- och materialteknik, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-34870.
Full textBaumdick, Martin [Verfasser], Philippe [Akademischer Betreuer] Bastiaens, and Roger S. [Gutachter] Goody. "Dynamic regulation of autocatalytic EGFR activation / Martin Baumdick ; Gutachter: Roger S. Goody ; Betreuer: Philippe Bastiaens." Dortmund : Universitätsbibliothek Dortmund, 2017. http://d-nb.info/1160443157/34.
Full textIwamura, Hiroshi. "Mechanistic insights from kinetic analysis by reaction calorimetry into proline-catalyzed asymmetric reactions and autocatalytic reaction." 京都大学 (Kyoto University), 2006. http://hdl.handle.net/2433/136952.
Full textPrušinskas, Kęstutis. "Investigation of the autocatalytic Cu(II) reduction processes in the systems with natural polyhydroxylic compounds as ligands." Doctoral thesis, Lithuanian Academic Libraries Network (LABT), 2013. http://vddb.laba.lt/obj/LT-eLABa-0001:E.02~2013~D_20130114_082011-57496.
Full textŠiame darbe tiriami polihidroksiliai alkoholiai sacharozė bei glicerolis, kaip ligandų alternatyvos cheminio variavimo sistemoms su reduktoriumi formaldehidu. Tai yra ekologiškos, biologiškai lengvai suyrančios medžiagos. Šiame darbe atlikti šių medžiagų kompleksų pusiausvyros skaičiavimai, eksperimentai parodantys sacharozės bei glicerolio praktinį pritaikomumą cheminio variavimo sistemose. Ultragarso poveikio cheminėms sistemoms dėsningumai dar nėra vienareikšmiškai ištirti ir suprasti. Siekiant padaryti cheminį metalų nusodinimą efektyvesniu pastaruoju metu cheminio metalizavimo procesams bandoma taikyti ultragarsą. Atlikti tyrimai parodė, kad naudojant sacharozę ir glicerolį ligandais cheminio variavimo tirpaluose vario nusėdimo greitis optimaliomis sąlygomis siekia atitinkamai 2,2 ir 3,4 m/h, o chemiškai nusodinto vario paviršiaus šiurkštumo faktoriai varijuoja 8,5-25,3 ir 2,3-4,3 ribose. Analizuojant gautus duomenis stebimos koreliacijos tarp vario nusėdimo greičio, viršįtampio, paviršiaus šiurkštumo faktoriaus, formaldehido anodinės oksidacijos srovių maksimumų priklausomybių nuo pH. Ultragarso panaudojimas cheminio variavimo sistemose keičia vario nusėdimo greičius. Priklausomai nuo pasirinktos cheminio variavimo sistemos, ultragarso dažnio ar jo skleidimo būdo vario nusėdimo greitis sumažėja iki visiško proceso sustabdymo arba gali padidėti 2-5 kartus ir pasiekti dideles vertes (10,87 μm/h). Ultragarso aplinkoje dažniausiai susiformuoja kompaktiškesnės, lygesnės... [toliau žr. visą tekstą]
Gardner, Bryan (Bryan Jay). "Lean Transformations in Supply Chain, the autocatalytic nature of lean principles, and tactics for implementing lean tools." Thesis, Massachusetts Institute of Technology, 2008. http://hdl.handle.net/1721.1/43834.
Full textIncludes bibliographical references (p. 179).
Expanding Lean principles beyond the manufacturing floor, ultimately to entail a comprehensive Lean Enterprise, has gained increasing attention among corporations. This thesis entails a detailed case study of initiating a Lean Transformation in the Supply Chain department of a technology center for engineering, integration and final assembly of directional drilling equipment. This technology center is part of Schlumberger, a global corporation and industry leader in directional drilling and other oilfield technologies and services. Initiating the Lean Transformation in this Supply Chain department is detailed and used as the central theme throughout the thesis. The rapid, successive applications and results of conventional Lean principles are evaluated. Due to the near relative proximity of the several initiatives undertaken, in both time and within the organization, this case is used to evaluate the Autocatalytic Nature of Lean Principles within the Supply Chain department. Concurrently, the dynamics involved with the interactions of personnel within the department are evaluated. As a Lean Transformation is so heavily dependent upon the personnel participating in the change, tactics for initiating a Lean Transformation are treated in reference to the several initiatives of this case study. These three components, Lean principles, their autocatalytic interaction, and relevant human interactions, are all combined to comprehensively address the most influential aspects of affecting a Lean Transformation in a Supply Chain department.
by Bryan Gardner.
S.M.
M.B.A.
Miu, Kevin (Kevin K. ). "The development of autocatalytic structural materials for use in the sulfur-iodine process for the production of hydrogen." Thesis, Massachusetts Institute of Technology, 2006. http://hdl.handle.net/1721.1/36724.
Full textIncludes bibliographical references (p. 63).
The Sulfur-Iodine Cycle for the thermochemical production of hydrogen offers many benefits to traditional methods of hydrogen production. As opposed to steam methane reforming - the most prevalent method of hydrogen production today - there are no carbon dioxide emissions. Compared to other methods of hydrogen production, the efficiency of the cycle is excellent. Due to the high temperatures necessary for the cycle, which are generally greater than 8500C, several of the Generation IV nuclear reactor concepts are attractive thermal energy sources. However, the high temperature and corrosive reaction conditions of the cycle, involving reactions including the decomposition of H2SO4 at 400-9000C, present formidable corrosion challenges. The conversion of sulfuric acid to sulfur dioxide was the focus of this study. The alloying of structural materials to platinum has been proposed as a solution to this problem. A catalytic loop to test the materials was constructed. Sulfuric acid was pumped over the material at 903+20C. The sulfur dioxide production of the catalyst was measured as a means of quantifying the efficiency of the system as a function of temperature.
(cont.) The maximum possible production of the material was calculated by using a mass balance. A gas chromatograph was used to calculate the actual production of sulfur dioxide. The results of the experiment show that an molecular conversion efficiency of 10% is attained when operating at 900C while using 800H + 5%Pt as a catalyst. The research confirms the catalytic activity of the material.
by Kevin Miu.
S.B.
Boerner, Susann. "Probing reaction conditions and cofactors of conformational prion protein changes underlying the autocatalytic self-propagation of different prion strains." Doctoral thesis, Humboldt-Universität zu Berlin, Lebenswissenschaftliche Fakultät, 2014. http://dx.doi.org/10.18452/17003.
Full textPrions are the causative agent of transmissible spongiform encephalopathies in animals and humans such as scrapie, bovine spongiform encephalopathy (BSE) and Creutzfeldt-Jakob disease (CJD). Prions are thought to be composed essentially of a misfolded and aberrantly aggregated isoform of the cellular prion protein (PrP) and to replicate by seeded PrP polymerization. Prions may exist in the form of distinct strains that differ in their phenotypic characteristics although they are derived from the same cellular prion protein. Cofactor molecules other than PrP may be involved in prion replication and may be a determinant of strain properties. Furthermore, cofactors may also be required for conveying infectivity. The present study examined the effects of different cofactor molecules on the replication efficacy of four hamster adapted prion agents using the method of serial protein misfolding cyclic amplification (PMCA) as in vitro assay for PrP misfolding and aggregation. The study revealed strain dependent differences of PMCA conditions and cofactors required for efficient in vitro replication. The impact of cofactors was assessed by comparative analyses of selected biological, biochemical and biophysical properties of PMCA products (PrPres) and native prion seeds. The biological seeding activity as monitored in a primary hamster glial cell assay, and biochemical properties such as electrophoretic migration in SDS-gels, were affected differently by different cofactors. In order to define the impact of putative cofactors on the molecular conversion of PrP in more detail, changes in the spatial structure associated with different cofactor molecule conditions during amplification of PrPres in PMCA was monitored by Fourier transform-infrared (FT-IR) spectroscopic analysis. Largely preliminary data revealed spectral differences between native prion seeds and progeny PMCA generated PrPres for all prion strains, but no variations due to different cofactor conditions.
Chakraborty, Aryadeep Verfasser], Hans-Josef [Akademischer Betreuer] Allelein, Nabiha [Akademischer Betreuer] Chaumeix, and Heinz Günter [Akademischer Betreuer] [Pitsch. "Optimization of passive autocatalytic recombiners (PARs) with respect to gas-phase ignition / Aryadeep Chakraborty ; Hans-Josef Allelein, Nabiha Chaumeix, Heinz Pitsch." Aachen : Universitätsbibliothek der RWTH Aachen, 2020. http://d-nb.info/1225401674/34.
Full textGencer, Burcak. "Analysis Of Self-processing Mechanism Of Galactose Oxidase By Site-directed Mutagenesis And Heterologous Expression In Escherichia Coli." Master's thesis, METU, 2005. http://etd.lib.metu.edu.tr/upload/3/12607081/index.pdf.
Full textEC 1.1.3.9) from Fusarium graminearum
having a molecular mass of 68kDa, is a monomeric, copper containing enzyme with an unusual thioether bond. The enzyme is produced as a precursor with an additional 8 amino acid pre- and a 17- amino acid pro-sequence at the N terminus. Previous work has shown that the pre-peptide is removed possibly by a protease during secretion, whereas the 17 amino acid pro-peptide is removed autocatalytically by the aerobic addition of Cu2+ to the precursor, preceding the formation of the thioether bond at the active site. The pro-gao gene was on ProGON1 and ProGOMN1 constructs which were previously established on pET101/D/lacZ vector in England by directed evolution. ProGON1 contains silent mutations at the N-terminus different from native galactose oxidase whereas ProGOMN1 has six further mutations within the mature enzyme, providing high expression. The cleavage site mutations R-1P/A1P, R-1X/A1X, S2A, and the H522A mutation just against the cleavage site in the three dimensional configuration, were carried out by site-directed mutagenesis. Those and some extra mutations were confirmed by DNA sequence analysis. Next, mutant galactose oxidases were expressed in E. coli BL21 Star (DE3), and were purified by Strep-Tactin®
Sepharose®
column, operating on the basis of affinity chromatography. Subsequently, SDS-PAGE was performed to analyze self-processing by detecting molecular mass difference of protein bands resulting from pro-sequence removal or existence. When the bands obtained in SDS-PAGE were compared, it was seen that the products of original recombinant plasmids, i.e. ProGON1, ProGOMN1
and the mutational variants showed no difference in band size, all slightly above 70kDa
indicating pro-sequence presence on all constructs. Non-mutants and some of the mutants showed galactose oxidase activity, signifying proper active site construction by thioether bond formation. ProGOMN1 was submitted for N-terminal amino acid sequencing to be able to assert that a size above 70kDa is not solely due to the existence of a 1 kDa Strep-tag II at C-terminus. Sequencing data affirmed the presence of both the pre-peptide and the pro-preptide showing that processing has not occurred at the N-terminus. Accordingly, in this study, it was shown for the first time that the existence of a pre-pro-peptide at the N-terminus of galactose oxidase does not prevent thioether bond formation at the active site. Furthermore, since the pro-peptide is cleaved autocatalytically, the lack of removal of the pre-peptide in E.coli in the presence of Cu 2+ and oxygen is very likely to be the cause of lack of pro-peptide cleavage. In future studies the region corresponding to the pre-peptide will be deleted to prove this hypothesis.
Cardoso, Cristiano. "Revestimentos de níquel químico para proteção contra corrosão." Universidade de São Paulo, 2006. http://www.teses.usp.br/teses/disponiveis/3/3133/tde-11122006-132846/.
Full textThe autocatalytic nickel-phosphorus (NiP) or electroless nickel (EN) coatings are widely used to protect equipment and structures against corrosion and erosion, used in the exploitation of petroleum in deep waters. Even though NiP is considered as the most appropriate coating for this purpose, many premature failures are verified in service. This has been attributed to the differences in the characteristics of the coating due to the differences in the application processes and in the nature and preparation of the substrate surfaces. The lack of broad specifications that define the required characteristics of the good quality coating is responsible for those differences. The present work had as its objective to identify the main factors related to the NiP performance using statistical tools as: factorial design, best subset regression, multiple regression and contour diagram. The considered factors were: substrate type, substrate surface finishing, bath age, phosphorus content, thickness, heat treatment and impurities. The NiP coatings were characterized in agreement with the ISO 4527 and their performance was verified through the salt spray test (1 536 h), the Kesternish test (10 cycles) and the synthetic sea water immersion test (120 days). Electrochemical tests (linear polarization and electrochemical impedance spectroscopy) were conducted in order to compare them to the salt spray test and thus reducing the testing time. In the studied range, it was verified that the NiP performance is influenced by the following factors: substrate type, thickness coating, phosphorus content, bath age (MTO), heat treatment and the impurities: sulfur, lead, magnesium, copper, iron and manganese. It was possible to verify that the types of accelerated corrosion tests adopted in the current international standards are appropriate to verify the quality of the coatings. It was also verified that the electrochemical tests, despite being suitable to indicate the NiP intrinsic corrosion resistance, are not appropriate to verify the NiP porosity (which is the main indication of a cathodic coating quality). With the obtained results, it will be possible to establish a better specification in order to obtain NiP with good quality.
Gérard, Thomas. "Theoretical study of spatiotemporal dynamics resulting from reaction-diffusion-convection processes." Doctoral thesis, Universite Libre de Bruxelles, 2011. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/209861.
Full textDans ce contexte, le but de notre thèse a été d'étudier de manière théorique et sur des modèles réaction-diffusion-convection simples les propriétés de dynamiques spatio-temporelles résultant du couplage chimie-hydrodynamique.
Nous nous sommes focalisés sur les instabilités hydrodynamiques de digitation visqueuse et de densité qui apparaissent respectivement lorsqu'un fluide dense est placé au-dessus d'un fluide moins dense dans le champ de gravité et lorsqu'un fluide visqueux est déplacé par un fluide moins visqueux dans un milieu poreux.
En particulier, nous avons étudié les problèmes suivants:
- L'influence d'une réaction chimique de type A + B → C sur la digitation visqueuse. Nous avons montré que les structures formées lors de cette instabilité varient selon que le réactif A est injecté dans le réactif B ou vice-versa si ces réactifs n'ont pas un coefficient de diffusion ou une concentration initiale identiques.
- Le rôle de pertes de chaleur par les parois du réacteur dans le cadre de la digitation de densité de fronts autocatalytiques exothermiques. Nous avons caractérisé les conditions de stabilité de fronts en fonction des pertes de chaleur et expliqué l'apparition de zones anormalement chaudes lors de cette instabilité.
- L'influence de l'inhomogénéité du milieu sur la digitation de densité de solutions réactives ou non. Nous avons montré que les variations spatiales de perméabilité d'un milieu poreux peuvent figer ou faire osciller la structure de digitation dans certaines conditions.
- L'influence d'un champ électrique transverse sur l'instabilité diffusive et la digitation de densité de fronts autocatalytiques. Il a été montré que cette interaction peut donner lieu à des nouvelles structures et changer les propriétés du front.
En conclusion, nous avons montré que le couplage entre réactions chimiques et mouvements hydrodynamiques est capable de générer de nouvelles structures spatio-temporelles dont les propriétés dépendent entre autres des conditions imposées au système.
/
In industrial reactors or in nature, fluid flows can be coupled to chemical reactions. In many cases, the result is the emergence of complex structures whose properties depend among others on the geometry of the system.
In this context, the purpose of our thesis was to study theoretically using simple models of reaction-diffusion-convection, the properties of dynamics resulting from the coupling between chemistry and hydrodynamics.
We focused on the hydrodynamic instabilities of viscous and density fingering that occur respectively when a dense fluid is placed above a less dense one in the gravity field and when a viscous fluid is displaced by a less viscous fluid in a porous medium.
In particular, we studied the following issues:
- The influence of a chemical reaction type A + B → C on viscous fingering. We have shown that the fingering patterns observed during this instability depends on whether the reactant A is injected into the reactant B or vice versa if they do not have identical diffusion coefficients or initial concentrations.
- The role of heat losses through the reactor walls on the density fingering of exothermic autocatalytic fronts. We have characterized the conditions of stability of fronts depending on heat losses and explained the appearance of unusually hot areas during this instability.
- The influence of the inhomogeneity of the medium on the density fingering of reactive solutions or not. We have shown that spatial variations of permeability of a porous medium may freeze or generate oscillating fingering pattern under certain conditions.
- The influence of a transverse electric field on the Rayleigh-Taylor and diffusive instabilities of autocatalytic fronts. It was shown that this interaction may lead to new structures and may change the properties of the front.
In conclusion, we showed that the coupling between chemical reactions and hydrodynamic motions can generate new space-time structures whose properties depend among others, on the conditions imposed on the system.
Doctorat en Sciences
info:eu-repo/semantics/nonPublished
Boerner, Susann [Verfasser], Erwin [Akademischer Betreuer] Schneider, Michael [Akademischer Betreuer] Beekes, and Walter J. [Akademischer Betreuer] Schulz-Schaeffer. "Probing reaction conditions and cofactors of conformational prion protein changes underlying the autocatalytic self-propagation of different prion strains / Susann Boerner. Gutachter: Erwin Schneider ; Michael Beekes ; Walter J. Schulz-Schaeffer." Berlin : Lebenswissenschaftliche Fakultät, 2014. http://d-nb.info/1054728364/34.
Full textPalmieri, Elena [Verfasser], Günter von [Gutachter] Kiedrowski, and Sijbren [Gutachter] Otto. "Autocatalytic desymmetrization of prochiral compounds : strategies to dictate and control self-replication in peptidic dynamic combinatorial libraries / Elena Palmieri ; Gutachter: Günter von Kiedrowski, Sijbren Otto ; Fakultät für Chemie und Biochemie." Bochum : Ruhr-Universität Bochum, 2018. http://d-nb.info/1154307719/34.
Full textMenon, Shakti Narayana. "Bifurcation problems in chaotically stirred reaction-diffusion systems." Thesis, The University of Sydney, 2008. http://hdl.handle.net/2123/3685.
Full textMenon, Shakti Narayana. "Bifurcation problems in chaotically stirred reaction-diffusion systems." University of Sydney, 2008. http://hdl.handle.net/2123/3685.
Full textA detailed theoretical and numerical investigation of the behaviour of reactive systems under the influence of chaotic stirring is presented. These systems exhibit stationary solutions arising from the balance between chaotic advection and diffusion. Excessive stirring of such systems results in the termination of the reaction via a saddle-node bifurcation. The solution behaviour of these systems is analytically described using a recently developed nonperturbative, non-asymptotic variational method. This method involves fitting appropriate parameterised test functions to the solution, and also allows us to describe the bifurcations of these systems. This method is tested against numerical results obtained using a reduced one-dimensional reaction-advection-diffusion model. Four one- and two-component reactive systems with multiple homogeneous steady-states are analysed, namely autocatalytic, bistable, excitable and combustion systems. In addition to the generic stirring-induced saddle-node bifurcation, a rich and complex bifurcation scenario is observed in the excitable system. This includes a previously unreported region of bistability characterised by a hysteresis loop, a supercritical Hopf bifurcation and a saddle-node bifurcation arising from propagation failure. Results obtained with the nonperturbative method provide a good description of the bifurcations and solution behaviour in the various regimes of these chaotically stirred reaction-diffusion systems.
Burgess, D. J. "Autocatalysis in tributyl phosphate hydrolysis." Thesis, Swansea University, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.636178.
Full textKust, Paul Roger. "Micellar autocatalysis and mixed michelle thermodynamics." The Ohio State University, 1997. http://rave.ohiolink.edu/etdc/view?acc_num=osu1302028057.
Full textKust, Paul Roger. "Micellar autocatalysis and mixed micelle thermodynamics /." The Ohio State University, 1997. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487945015616522.
Full textBeauvier, Edouard. "Propagation d'un front de réaction-diffusion dans un écoulement cellulaire multi-échelle." Thesis, Aix-Marseille, 2013. http://www.theses.fr/2013AIXM4728/document.
Full textThe propagation of a reaction-diffusion front is experimentally studied in a multi-scale cellular flow. The front is produced by an autocatalytic chemical reaction in an aqueous solution. The flow is generated by electroconvection and its multi-scale nature is induced by overlaying magnets of different scales. This enables an independent tune of the flow intensity at each scale. The geometry and the mean velocity of the front have been determined over a large range of scale intensities. These features are confirmed by a numerical simulation based on a burnt and fresh domain dynamics, the burnt domain expanding across the fresh one. The effect of the multi-scale nature of the flow on the mean front velocity is recovered by a renormalisation method validated by a collapse of the data onto a single curve
Clairmont, Ryan Michael. "Azolium ions: A versatile framework for chemistry on early earth." Diss., Georgia Institute of Technology, 2016. http://hdl.handle.net/1853/55021.
Full textBillingham, John. "Travelling waves and clock reactions in quadratic and cubic autocatalysis." Thesis, University of East Anglia, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.280446.
Full textMcGarry, John Kevin. "Application of bifurcation theory to physical problems." Thesis, University of Leeds, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.252925.
Full textMcCabe, Philip M. "The mathematical analysis of a class of singular reaction-diffusion systems." Thesis, University of Reading, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.301978.
Full textSubramaniam, C. "Chemorhelogical Modeling Of Amine-Cured Multifunctional Epoxy Resin Systems Used As Matrices In Aerospace Composites." Thesis, Indian Institute of Science, 1994. http://hdl.handle.net/2005/127.
Full textPaez, Espejo Miguel angel. "Modélisation et simulation du comportement spatiotemporel des transitions de phase dans les monocristaux moléculaires à transition de spin." Thesis, Université Paris-Saclay (ComUE), 2016. http://www.theses.fr/2016SACLV034/document.
Full textThis work is devoted to the multiscale modeling of the spin transition phenomena in Fe(II) spin crossover compounds. The development of a macroscopic reaction-diffusion-like model for the phase transition from the Ising-like Hamiltonian allowed the theoretical study of the spatio-temporal behavior of the high-spin fraction accompanying the first-order phase transition in switchable spin crossover single crystals. The comparison to experiments led to an excellent agreement for the dynamics of the high-spin/low-spin interface which improved the understanding of the optical microscopy measurements. Next, this work was extended to the study of photothermic effects due to the crystal heating by the light of the microscope leading to a coupled system of differential equations accounting for the thermal coupling with the bath temperature. These equations predict nonlinear behaviors for crystals in the bistable region, such as the autocatalytic effects, for which we established the conditions of their emergence. The last part of this thesis is devoted to an extension of the electro-elastic model. Here we prove that the elastic frustration is at the origin of the existence of two-step and of incomplete spin crossover transitions. Furthermore, this model allowed us to predict structures of complex patterns in high-spin fractions for intermediate phases. Several types of self-organisation were revealed such as the spatially-modulated structures of the high-spin fractions. Some of these behaviors have been experimentally observed, very recently, in spin crossover compounds
Eickes, Christian. "Die autokatalytische H 2 O 2 -Reduktion an Ag-Elektroden." Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät I, 2001. http://dx.doi.org/10.18452/14597.
Full textRecently, it was shown that the hydrogen peroxide (H2O2) reduction on silver in perchloric acid (HClO4) proceeds in two parallel paths. The normal reduction is observed at an overpotential of -1.5 V, whereas a second reduction reaction occurs at a significantly lower overpotential at -1.0 V. The second reaction involves the unstable intermediate OHad, which also acts as a catalyst. Hence, the second reaction has been proposed to be an autocatalytic one. This autocatalytic reaction is deactivated after a certain time that depends on the rotation speed of the electrode. It can be recovered if the electrode is negatively polarized. In this thesis work, ex-situ XPS measurements on emersed Ag(111) electrodes were conducted. The analysis leads to the conclusion that the deactivation is caused by a small amount of chloride contamination. Electrochemical impedance spectra are presented together with numerical simulations for the faradaic impedance in the autocatalytic region based on previously suggested kinetic rate laws. The experimental data fit well with the results of the theoretical calculations, which strongly supports the autocatalytic mechanism.
Eilerts, Diane. "Recombinant Expression and Potential Autocatalysis of Aedes aegypti Trypsin-Like Serine Proteases (AaSPII and AaSPIV)." Thesis, San Jose State University, 2017. http://pqdtopen.proquest.com/#viewpdf?dispub=10284010.
Full textAedes aegypti mosquitoes can be found globally in tropical and subtropical urban areas and spread Zika, Dengue fever, yellow fever, and Chikungunya viruses. Current vector control methods are limited and nonspecific. The female Ae. aegypti mosquito uses blood meal proteins to obtain nutrients required for oogenesis; inhibition of the midgut trypsin-like serine proteases responsible for blood meal digestion may provide a novel method of vector control. Ae. aegypti blood meal digestion is complex and the role of uncharacterized serine proteases in blood digestion is unclear; specifically, a group of trypsin-like serine proteases (AaSPII–V) is expressed at constant levels before and following Ae. aegypti blood meal acquisition. This research focuses on the in vitro biochemical study of two specific Ae. aegypti trypsin-like serine proteases (AaSPII and AaSPIV) in order to gain further understanding of their role in blood meal digestion. The approach involved the successful cloning and bacterial expression of these soluble, recombinant proteases. Results from attempts to purify these proteases were unsuccessful but indicative of potential autocatalytic and autodigestive behavior. Future studies will focus on obtaining purified recombinant proteases for further study. The study of AaSPII and AaSPIV, as well as other midgut Ae. aegypti proteases, will aid in understanding the overall role proteases play in blood meal digestion and may eventually allow for the development of mosquito-specific enzyme inhibitors.
Poletti, Patrick David. "The Effect of Dynamic Kinetic Selection on an Evolving Ribozyme Population." Thesis, Portland State University, 2019. http://pqdtopen.proquest.com/#viewpdf?dispub=13422098.
Full textDynamic Kinetic Selection (DKS) suggests that kinetic, rather than thermodynamic, stability will dictate the composition of a replicating population of biomolecules. Here, the results obtained from a series of five related reactions involving gradually increasing percentages of randomly-mutated substrate fragments to generate variants of full-length Azoarcus group I intron through an autocatalytic self-assembly reaction involving a series of recombination events, showed DKS as a driving factor in dictating the population composition of full-length product assembled from substrates that had fewer positions available to randomization.
In trying to elucidate a plausible scheme for the origins of complex biomolecules on the prebiotic Earth, the suggestion that networks comprised of interacting molecules were more likely to evolve into biomolecules capable of obtaining and sustaining characteristics attributed to living molecules has gained traction within the past few years. Of specific interest is the catalytic efficacy of ribozymes whose genotypes require that they interact with molecules of the same genotype (selfish systems) to be effective catalysts versus those that are more effective when accomplishing catalysis by cooperating with ribozymes of a different genotype (cooperative systems). Here, the Azoarcus I ribozyme was used to compare these two types of system. Both systems were shown to robustly produce full-length product. Two different methods of introducing random mutations into substrate fragments for the reactions described in this thesis were employed. The differences in the preparation methods for the substrates was not expected to have an impact on the nature of the full-length product. However, there was no correlation between the positions that tended to be more tolerant of accepting random mutations between the products arising from the two preparation methods. One preparation method yielded full-length ribozymes more consistent with the secondary structure of the wild-type ribozyme and followed substitution patterns found in in vivo nucleic acid substitutions, whereas the other method provided full-length ribozymes that tolerated mutations that would be expected to greatly affect the secondary structure of the ribozyme and those positions tended to mutate evenly to any of the three possible alternative nucleobases.
Point mutations introduced into ribozyme substrate fragments may have a deleterious, neutral, or beneficial effect, depending on their impact on the catalytic capability of the molecule vis-á-vis the effect, if any, the change has to the secondary and tertiary structure of the ribozyme. In this dissertation, the results of two series of point mutation reactions are addressed. The first set showed a point mutation to have a deleterious effect, whereas concerted mutations did not significantly affect activity of the ribozyme. The second series of reactions involved point mutations at a position that had previously been determined to be highly tolerant of random mutations. Results suggested that substitutions at this position had a minimal impact on ribozyme activity.
Rayder, Thomas M. "Modulation of Catalyst@MOF Host-Guest Composites in Pursuit of Synthetic Artificial Enzymes:." Thesis, Boston College, 2020. http://hdl.handle.net/2345/bc-ir:108930.
Full textThesis advisor: Chia-Kuang (Frank) Tsung
Biological systems have evolved over time to favor structures beneficial for the efficient transformation of simple feedstocks to sophisticated products. In particular, enzymes have evolved such that cooperative and geometrically controlled interactions between active sites and substrates enhance catalytic activity and selectivity. Separation of these active sites from other incompatible catalytic components allows for chemical transformation in a stepwise fashion, circumventing the inherent limitations to performing reactions in a single step. This dissertation describes the use of porous crystalline materials called metal-organic frameworks (MOFs) as hosts to mimic the component separation and precise active site control observed in nature. The first phase of these efforts explores the use of dissociative “aperture-opening” linker exchange pathways in a MOF to encapsulate transition metal complexes for carbon dioxide hydrogenation to formate. This strategy is then used to separate two incompatible complexes and perform the cascade conversion of carbon dioxide to methanol, resulting in unique and previously unobserved network autocatalytic behavior. Finally, the modularity of the MOF host is leveraged to install beneficial functionality in close proximity to the encapsulated transition metal complex, leading to activity exceeding that of any reported homogeneous system for carbon dioxide reduction. The insights gained through these studies can inform the development of composites for other reactions, allowing for access to new and unique reaction manifolds
Thesis (PhD) — Boston College, 2020
Submitted to: Boston College. Graduate School of Arts and Sciences
Discipline: Chemistry
Uwaha, Makio, and Hiroyasu Katsuno. "Mechanism of Chirality Conversion by Grinding Crystals -Ostwald Ripening vs Crystallization of Chiral Clusters-." The Physical Society of Japan, 2009. http://hdl.handle.net/2237/13866.
Full textHe, Lichun [Verfasser], and Christiane [Akademischer Betreuer] Ritter. "Structural basis for signaling in innate immunity via autocatalytical changes of MAVS by NMR / Lichun He ; Betreuer: Christiane Ritter." Braunschweig : Technische Universität Braunschweig, 2014. http://d-nb.info/1175820369/34.
Full textUwaha, Makio. "Simple Models for Chirality Conversion of Crystals and Molecules by Grinding." The Physical Society of Japan, 2008. http://hdl.handle.net/2237/13865.
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