Дисертації з теми "Hydroxyle radical"
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Alkhuraiji, Turki. "Ionisation par faisceau d'électrons de solutions aqueuses de benzènesulfonate et naphthalènesulfonate et sous-produits." Thesis, Poitiers, 2013. http://www.theses.fr/2013POIT2259/document.
Повний текст джерелаThis research belongs to the study of the ionization of aqueous solutions by electron beam (E.B.) as an advanced oxidation process for water treatment. The hydroxyl radical (•OH) and hydrated electron(eaq¯) are the two major active species produced from the ionization of aqueous solutions by high energy electron beam. It has been shown that the generation of additional radicals such as the sulphate radical (SO4•¯) and hydroxyl radical from the reaction of persulfate ion (S2O8¯) or hydrogen peroxide (H2O2) with the hydrated electron, improved the efficiency of this process towards the degradation and mineralization of organic pollutants in aquaeous solution. In the présent work, the degradation and mineralization of naphthalenesulfonate, benzenesulfonate and gallic acid were studied by electron beam irradiation alone and coupled with oxidants (S2O8¯, H2O2).In the absence of oxidant, an absorbed dose of 1,5 kGy leads to total elimnation of these pollutants. The presence of added oxidants usually reduces the radiation dose required. In addition, increasing oxidant concentration or applied dose had a beneficial effect towards the organic carbon removal. It was found that coupling E.B./S2O8¯ has more suitable than E.B./ H2O2 even in the presence of inorganic constituents. The results also highlighted the importance of dissolved oxygen in the system when mineralization is aimed. For each of the molecules studied, oxidation by-products resulting from hydroxylation and aromatic ring opening were identified
Varmenot, Nicolas. "Processus d'oxydation des sulfures organiques par le radical hydroxyle : influence du groupement S-acétyle." Paris 5, 2001. http://www.theses.fr/2001PA05S019.
Повний текст джерелаDemougeot, Céline. "Etude de la toxicité cérébrale du fer et évaluation du N-Acétyl-L-aspartate comme marqueur biochimique de la mort neuronale : application à l'ischémie cérébrale." Dijon, 2001. http://www.theses.fr/2001DIJOPE02.
Повний текст джерелаAbila, Paul-André. "Application de la spectroscopie moléculaire au diagnostic d'un plasma inductif d'argon." Lyon, INSA, 1989. http://www.theses.fr/1989ISAL0074.
Повний текст джерелаEl, Omar Abdel Karim. "Études des réactions primaires en solutions par la radiolyse pulsée picoseconde." Phd thesis, Université Paris Sud - Paris XI, 2013. http://tel.archives-ouvertes.fr/tel-00931405.
Повний текст джерелаBrosse, Fabien. "Influence de la couche limite convective sur la réactivité chimique en Afrique de l'Ouest." Thesis, Toulouse 3, 2017. http://www.theses.fr/2017TOU30324/document.
Повний текст джерелаThis thesis focuses on the influence of the convective and cloudy boundary layer on the chemical reactivity in West Africa. To answer this question, high resolution simulations (50m) are performed on the atmospheric model Meso-NH coupled to a detailed chemical scheme representing the gaseous and aqueous phases. This spatial scale allow to explicitly represent the spatial and temporal characteristics of turbulent structures. Thermals in the boundary layer are identified by a conditional sampling based on a radioactive-decay passive scalar. The turbulent transport influence on the redistribution of chemical species depends on the chemical lifetimes of these species. Spatial segregation is created within the convective boundary layer that increases or decreases the mean reaction rates between compounds. AMMA campaign field study, and more recently DACCIWA, are used to define dynamical and chemical forcing of two simulated environments. The first one is representative of a biogenic environment dominated by natural emissions of VOC. The second reproduces a moderately polluted typical urban area of the Guinean Gulf (Cotonou in Benin). For the sake of simplicity, simulations analysis are limited to the chemical reaction between isoprene and OH in the biogenic case, and the reaction between C>2 aldehydes and OH in the anthropogenic case. The convective boundary layer influence is studied at thermal and domain scale. This makes the connection with coarse resolution models for which a hypothesis of perfect and immediate mixing is made, neglecting the spatial variability of chemical species within a grid cell. The first results are based on the gaseous phase only. Cloudy development in the convective boundary layer only affects the vertical transport of chemical species. The simulations show that thermals are preferential reaction zones where the chemical reactivity is the highest. The top of the boundary layer is the region characterized by the highest calculated segregation intensities but of the opposite sign in both environments. In the biogenic environment, the inhomogeneous mixing of isoprene and OH in this zone leads to a maximum decrease of 30% of the mean reaction rate. In the anthropogenic case, the effective rate constant for OH reacting with aldehydes is 16% higher at maximum than the averaged value. The OH reactivity is higher by 15 to 40% inside thermals compared to the surroundings depending on the chemical environment and time of the day. Because thermals occupy a small fraction of the simulated domain, the impact of turbulent motions on the domain-averaged OH total reactivity reaches a maximum 9% decrease for the biogenic case and a maximum of 5% increase for the anthropogenic case. LES simulations including the aqueous reactivity reveal a significant decrease in OH mixing ratios associated to the presence of clouds. Consequently, isoprene and C>2 aldehydes mixing ratios increase at these altitudes
Oppilliart, Sophie. "Etude par échange isotopique du radical tyrosyle en solution et dans la catalase bovine." Phd thesis, Université Paris Sud - Paris XI, 2007. http://tel.archives-ouvertes.fr/tel-00361211.
Повний текст джерелаPar ailleurs, il a été montré au laboratoire que l'identification et la quantification des radicaux formés sur les acides aminés d'une protéine par l'attaque de radicaux hydroxyle sont possibles. Cette méthode est basée sur le marquage au tritium des résidus acides aminés. Notre approche est basée sur la génération de radicaux hydroxyle par radiolyse de l'eau. Les radicaux hydroxyle formés arrachent un hydrogène sur la chaîne latérale des acides aminés et génèrent ainsi un radical carboné. Il est ensuite “réparé” in situ par un composé, le sel sodique de l'acide phénylphosphinique tritié, qui permet d'introduire un atome de tritium à la place de l'hydrogène précédemment arraché. Cet atome de tritium sert de marqueur pour détecter les sites de formation des radicaux.
Nous avons donc utilisé les propriétés de réparation du vecteur tritié pour identifier quelle est la tyrosine impliquée dans les transferts d'électrons de la BLC. Même s'il a été montré par RPE que la disparition du radical porté par la tyrosine est effective en présence de l'agent de réparation, les études de marquage n'ont pas abouti à déterminer l'exacte localisation du radical. Une des raisons invoquées est le manque d'efficacité de l'agent de réparation pour transférer son atome d'hydrogène. C'est pourquoi d'autres composés capables eux aussi de fournir un atome d'hydrogène par voie radicalaire ont été synthétisés puis testés sur ce système enzymatique par une étude de spectroscopie RPE.
En parallèle, nous avons voulu comprendre les mécanismes d'action des ces mêmes composés sur un système modèle en générant des radicaux sur la tyrosine en solution par radiolyse de l'eau. La méthode consiste à produire dans une solution aqueuse de tyrosine des radicaux hydroxyle, qui vont former les radicaux tyrosyle. Les radicaux ainsi générés peuvent être ensuite réparés par un atome de deutérium fourni par un donneur. L'incorporation en deutérium et la régiosélectivité de l'attaque sont ensuite analysées par spectrométrie de masse et RMN 2H. L'irradiation de solution de tyrosine en présence des différents composés choisis s'est révélée difficile à analyser, en raison notamment de la difficulté à déterminer la proportion de radicaux hydroxyle réagissant avec l'agent réparateur au lieu de la tyrosine, mais surtout en raison de l'incorporation inattendue de deutérium dans la tyrosine en l'absence de tout agent de transfert. Ce phénomène jusqu'alors inconnu a, dès lors, retenu toute notre attention. Nous avons alors focalisé nos travaux sur la compréhension des processus intervenant dans l'autoréparation de la tyrosine et ainsi proposé un mécanisme pour expliquer nos observations.
Lallement, Audrey. "Impact des processus photochimiques et biologiques sur la composition chimique du nuage." Thesis, Université Clermont Auvergne (2017-2020), 2017. http://www.theses.fr/2017CLFAC066/document.
Повний текст джерелаIn the context of global warming, more precise knowledge of atmospheric processes is needed to evaluate their impact on the Earth radiative budget. Clouds can limit the increase of temperature but this retroaction is not well understood due to a lack of knowledge of cloud media (like organic fraction composition). From the beginning of atmospheric studies, only chemical, especially radical, reactions was taken into account. However microorganisms metabolically active were found in cloud water arising questions about their role as biocatalyst. They are able to use carboxylic acids as nutriments, to degrade radical precursor (like H2O2) and to survive oxidative stress. The aim of this work is to quantify the impact of photochemical and biological processes on cloud chemistry composition. First, the concentrations of •OH, the most reactive radical, were evaluated and the influence of microorganisms on the concentrations were studied. A new method was developed in artificial medial before direct quantification of steady state •OH concentration in atmospheric waters (rain and cloud waters). Concentrations ranged from 10-17 to 10-15 M and did not change in presence of microorganisms. These measures were lower than concentrations estimated by chemical atmospheric models. A possible explanation was an underestimation of the main sink of this radical (organic matter). To better characterize this fraction, simple aromatic compounds were identified in cloud waters, phenol was found in the 8 samples analyzed. To go further, we studied phenol degradation in detail. Enzyme transcripts involved in phenol degradation were present in cloud water samples showing in situ activity of native bacteria. 93% of tested cultural strains, isolated from cloud waters, were able to degrade phenol. To quantify the relative contribution of radical versus microbial processes allowing phenol degradation, we performed photo-biodegradation experiment with a model strain (Rhodococcus erythropolis PDD-23b-28). Our results showed that these two processes participated equally to phenol degradation, suggesting that microorganisms and radicals can be involved in atmospheric natural remediation
Rabat, Hervé. "Utilisation du spectre UV du radical OH dans la métrologie des hautes températures des gaz chauds et des plasmas." Orléans, 2004. http://www.theses.fr/2004ORLE2050.
Повний текст джерелаJoshi, Prasad. "Isolation and reactivity of hydroxyl radical with astrochemically and atmospherically relevant species studied by Fourier transform infrared spectroscopy." Paris 6, 2012. http://www.theses.fr/2012PA066092.
Повний текст джерелаOH radicals play a fundamental role in the chemistry of interstellar media. The isolation and the characterization of the highly reactive species is challenging and represents an important prerequisite for reactivity studies that might be crucial in different fields such as astrochemistry and atmospheric chemistry. Different experimental approaches were tested to produce OH radicals. First of all, gaseous pure water was subjected to a microwave discharge. The species thus formed were condensed onto a cryogenic mirror maintained at 3 K and further characterized with a Fourier-transform IR spectrometer (FTIR). Under these conditions, radical recombination lead to the formation of a water-ice and the presence of OH radicals cannot be clearly established. Gaseous water was diluted into different rare gases (RG = He, Ne, Ar) prior to their introduction into the microwave discharge source. This approach allows to isolate and characterize OH radicals both in solid phase (RG = He) and in neon matrix (RG = Ne). Further reactivity experiments were carried out between these radicals and small species such as H2O, CO, NO, N2, O2, and CH4 in solid phase as well as in neon matrix
CATRY-FRANZINI, ELISABETH. "Comparaison des effets biologiques du radical hydroxyle genere par la reaction de fenton ou par la radiolyse de l'eau." Paris 11, 1993. http://www.theses.fr/1993PA112266.
Повний текст джерелаBianco, Angelica. "Formation photoinduite du radical hydroxyle dans la phase aqueuse du nuage : impact sur les acides carboxyliques et les acides aminés." Thesis, Clermont-Ferrand 2, 2016. http://www.theses.fr/2016CLF22746/document.
Повний текст джерелаClouds represent a multiphase complex and reactive medium in which gases, liquid particles and aerosols are in continuous interaction. A large fraction of atmospheric chemical compounds present in the particulate and gaseous phases can be transferred to the cloud droplets where can undergo chemical, photochemical and microbiological transformations. Cloud waters were sampled at the puy de Dôme station. The first part of my PhD work is focused on the photoreactivity of cloud water. Formation of a reactive species such as hydroxyl radical, by direct photolysis of inorganic sources was investigated, as well as the correlation between the concentration of sources and the hydroxyl radical formation rate. The spectroscopic proprieties and fate of tartronic acid, were investigated under cloud water conditions. Moreover, photochemical experiments were performed using continuous irradiation (direct and hydroxyl radical mediated photolysis) and nanosecond flash photolysis in order to assess the reactivity of this compound in cloud aqueous phase. The second part of my work is centered on the characterization of organic matter in clouds. Two studies are presented: i) Detection and quantification of tryptophan by fluorescence spectroscopy and the assessment of its reactivity; ii) detection and quantification of amino acids. Amino acids are detected for the first time in cloud water using a derivatization method and this work show that they represent the 9% of the dissolved organic matter in cloud. Their reactivity with hydroxyl radical was compared to the reactivity of carboxylic acids and dissolved organic matter. These results clearly demonstrate that amino acids represent a major sink of hydroxyl radicals in cloud water
Louit, Guillaume. "Développement de sondes fluorescentes du radical hydroxyle : caractérisation et modélisation de la réactivité de molécules dérivées de la coumarine avec HO." Paris 11, 2005. http://www.theses.fr/2005PA112170.
Повний текст джерелаThe hydroxyl radical is involved in a wide range of different fields, from oxidative stress to atmospheric chemistry. In addition to the study of oxidative damage in biological media, the hydroxyl radical detection allows to perform a dosimetry when it is produced by ionising radiation. The aims of this work have been double:- to improve the detection of the hydroxyl radical by the design of new probes- to improve knowledge on the reactive pathways in which the hydroxyl radical is involved. We have studied the coumarin molecule, as well as 6 derivatives that we have synthesised, as fluorescent probes of the hydroxyl radical. Firstly, fluorescence spectroscopy and HPLC chromatography have allowed the evaluation of the sensibility and selectivity of detection of the probes. Consequently to this study, two applications have been developed, concerning the determination of rate constants by competition kinetics and bidimentional dosimetry. Secondly, we have studied the reactivity of the hydroxyl radical through the regioselectivity of its addition on the aromatic cycle. This problem was addressed by the combined use of experimental methods such as time resolved kinetics and HPLC along with interpretation from classical and ab initio modelisation
Wu, Yanlin. "Application of Fe(III)-EDDS complex in advanced oxidation processes : 4-ter-butylphenol degradation." Thesis, Clermont-Ferrand 2, 2014. http://www.theses.fr/2014CLF22455/document.
Повний текст джерелаAdvanced Oxidation Processes (AOPs) have been proved to be successfully applied in the treatment of sewage. It can decolorize the wastewater, reduce the toxicity of pollutants, convert the pollutants to be a biodegradable by-product and achieve the completed mineralization of the organic pollutants. The Fenton technologies which are performed by iron-activated hydrogen peroxide (H2O2) to produce hydroxyl radical (HO•) has been widely investigated in the past few decades. Recently, Sulfate radical (SO4•-) which was produced by the activation of persulfate (S2O82-) is applied to the degradation of organic pollutants in water and soil. It is a new technology recently developed. It is also believed to be one of the most promising advanced oxidation technologies.In this study, a new iron complex is introduced to the traditional Fenton reaction. The ferric iron (Fe(III)) and Ethylene diamine-N,N′-disuccinic acid (EDDS) formed the complex named Fe(III)-EDDS. It can overcome the main disadvantage of traditional Fenton technology, which is the fact that traditional Fenton technology can only perform high efficiency in acidic condition. Simultaneously, EDDS is biodegradable and it is one of the best environment-friendly complexing agents. On the other hand, the transition metal is able to activate S2O82- to generate SO4•-. Therefore, Fe(III)-EDDS will also be applied to activate S2O82- in the present study. 4-tert-Butylphenol (4-t-BP) has been chosen as a target pollutant in this study. It is widely used as a chemical raw material and is classified as endocrine disrupting chemicals due to the estrogenic effects. The 4-t-BP degradation rate (R4-t-BP) is used to indicate the efficiency of the advanced oxidation processes which are based on Fe(III)-EDDS utilization. The main contents and conclusions of this research are shown as follows:In the first part, the chemical structure and properties of Fe(III)-EDDS and the 4-t-BP degradation efficiency in UV/Fe(III)-EDDS system were studied. The results showed that Fe(III)-EDDS was a stable complex which was formed by the Fe(III) and EDDS with the molar ratio 1:1. From the photoredox process of Fe(III)-EDDS, the formation of hydroxyl radical was confirmed including that HO• is the main species responsible for the degradation of 4-t-BP in aqueous solution. Ferrous ion (Fe(II)) was also formed during the reaction. With the increasing Fe(III)-EDDS concentration, 4-t-BP degradation rate increased but is inhibited when the Fe(III)-EDDS concentration was too high. Indeed, Fe(III)-EDDS is the scavenger of HO•. pH value had a significant effect on the degradation efficiency of 4-t-BP that was enhanced under neutral or alkaline conditions. On the one hand, Fe(III)-EDDS presented in the FeL-, Fe(OH)L2-, Fe(OH)2L3-, Fe(OH)4- four different forms under different pH conditions and they had different sensitivity to the UV light. On the other hand, pH value affected the cycle between Fe(III) and Fe(II ). The formation of hydroperoxy radicals (HO2•) and superoxide radical anions (O2•-) (pka = 4.88) as a function of pH was also one of the reasons. It was observed that O2 was an important parameter affecting the efficiency of this process. This effect of O2 is mainly due to its important role during the oxidation of the first radical formed on the pollutant. (...)
Bonard, Amélie. "Etude cinétique de réactions élémentaires d'intérêt pour la combustion : application aux réactions du radical OH avec des éthers et des acétals." Orléans, 2000. http://www.theses.fr/2000ORLE2029.
Повний текст джерелаLudwig, Nicolas. "Modification d’acides aminés et de protéines en milieux aqueux sous faisceau d'ions." Thesis, Strasbourg, 2018. http://www.theses.fr/2018STRAE020/document.
Повний текст джерелаThe goal of this thesis is to achieve a better understanding of fundamental mechanisms of the radiolysis of biomolecules by accelerated ions, at the molecular scale. To do so, different type of ions have been used (H+, He2+, C6+) at various energies, corresponding to densities of energy deposition from 0,3 to 1000 eV/nm.The main component in biological systems is water. Therefore, the comprehension of the water radiolysis under ions irradiation is essential. One of the most reactive species produced in aerated conditions, the hydroxyl radical (HO•), has been quantified using a specific probe, the 3- carboxylic acid coumarin.Indirect effects of radiolysis on biomolecules, involving water radiolysis species, have been studied in dilute aqueous solutions on two different systems: phenylalanine, an amino acid, and a protein, myoglobin. Direct radiolysis effect were studied on concentrated hydrogels of myoglobin ad other proteins. Elucidation of radiolysis mechanisms and quantification of phenylalanine radiolysis products were systematically performed
Faider, Wilfrid. "Traitement de l’acétaldéhyde par décharges électriques impulsionnelles dans les mélanges de gaz atmosphériques : cinétique et efficacité énergétique." Thesis, Paris 11, 2013. http://www.theses.fr/2013PA112023/document.
Повний текст джерелаThe present study deals with the kinetics analysis of acetaldehyde (CH₃CHO) conversion in electrical discharges with different spatial qualities et at room temperature. Acetaldehyde concentrations up to 5000 ppm in nitrogen-based gas mixture containing up to 20% of oxygen have been investigated. Three different plasma reactors were used: an UV510 reactor producing a homogeneous plasma thanks to a pre-ionization by UV radiation (photo-triggered), a plane-to-plane and a rod-tube dielectric barrier discharges (DBDs) reactors, In both DBDs reactors discharges were driven by high voltage pulses allowing the production of weakly inhomogeneous plasma in the plane geometry and highly filamentary discharges in the cylindrical one. A high speed imaging diagnostic (ns range) of the plane-to-plane DBD shows that the plasma can be considered quasi-homogeneous. Based on a self-consistent 0D model, the kinetics study of the N₂/CH₃CHO mixture conversion in the photo-triggered discharge shows the importance of nitrogen molecule metastable states , i.e. the triplet A³Σu⁺ and the singlets group a' ¹∑⁻u, a ¹∏g, et w ¹Δu, in the acetaldehyde dissociation process. A minimum coefficient of 6.5×10⁻¹¹ cm³.s⁻¹ has been estimated for the quenching of N₂ singlets state by acetaldehyde. For the triplet states quenching the coefficient of has been evaluated between 4.2×10⁻¹¹ cm³.s⁻¹ and 6.5×10⁻¹¹ cm³.s⁻¹. This dissociation process produces radicals as CH₃, CH₃CO, HCO, H, O, and molecules like CH₄, CH₂CO, C₂H₄, C₂H₂, H₂, CO. Thus, the major by-products detected at the end of the post-discharge time are methane, hydrogen, carbon monoxide and ethane; smaller amounts of acetylene, ethene, acetone and acetonitrile were also detected. In containing oxygen mixtures, the importance of the CH3CHO dissociation processes due to N₂ metastable states quenching of decreases in favor of oxidation processes promoted by the hydroxyl radical, OH, and atomic oxygen, O (³P). Time-resolved measurements of the OH radical in the photo-triggered post-discharge show a very high reactivity of this radical with the by-products of acetaldehyde conversion. A maximum density of OH radical equal to 3.5×10¹⁴ cm⁻³ was measured for 10% oxygen and 5000 ppm of acetaldehyde. The kinetic scheme adopted in the self-consistent model for the same gas mixture gives a higher density value; by the way the model is in good agreement with the acetaldehyde conversion in N₂/O₂/CH₃CHO mixtures, as well as with the methane and ethane produced concentrations. Finally, the comparison of the three studied reactors energy efficiency shows that, for low oxygen content (less than 2%), the homogeneity of the discharge promotes the acetaldehyde conversion
Lendar, Maria. "Dégradation atmosphérique d’une série d’alcools, d’esters et de l’hexafluoroisobutène." Thesis, Orléans, 2012. http://www.theses.fr/2012ORLE2042/document.
Повний текст джерелаIn this thesis we report the atmospheric fate of three saturated alcohols: CH3(CH2)4OH, CH3CH2CH2CH(OH)CH3 and (C2H5)2CHOH, three esters: CH3CH2CH2C(O)OC2H5, CH3CH2COOC2H5 and CH3CH2COOCH2CH2CH3 and an unsaturated HFC with OH radicals and Cl atoms. The rate coefficients of OH reactions with these compounds have been measured over the temperature range 253 – 373 K, using the Pulsed Laser Photolysis – Laser Induced Fluorescence technique (PLP-LIF). Moreover the rate coefficients of OH and Cl reactions with alcohols, esters and hexafluoroisobutene (HFIB) have been determined at room temperature, using smog chambers. For the reaction of OH radicals with HFIB and Cl atoms with esters and HFIB, the rate coefficients obtained in this study present the first determination. The results have been compared with the literature and the reactivity of the compounds has been discussed. Finally, the atmospheric lifetimes of these compounds have been determined and the OH oxidation products have been identified, which allows us to estimate the atmospheric impact of these compounds
Tabelsi, Souhaila. "Dépollution des effluents industriels tunisiens chargés en polluants organiques persistants par les procédés d'oxydation avancée." Phd thesis, Université de Marne la Vallée, 2011. http://tel.archives-ouvertes.fr/tel-00742438.
Повний текст джерелаGilles, Manon. "Quantification des espèces radicalaires produites en présence de nanoparticules d’or soumises à un rayonnement ionisant." Thesis, Paris 11, 2015. http://www.theses.fr/2015PA112120/document.
Повний текст джерелаTo improve radiotherapy efficiency, radiosensitizers such as gold nanoparticles (GNP) are developed. But to translate them to clinics, a good knowledge of the processes at stage is needed. GNP radiosensitizing effect was well-confirmed on biological targets (DNA, cells and in vivo) and hydroxyl radicals are often proposed to be key intermediates, but no clear evidence has been given yet. In this work, we first developed a ‘reference’ protocol to quantify hydroxyl radicals and electrons produced by GNP in their interaction with ionizing radiation. These investigations reveal a massive production of both species for non-functionalized GNP. Moreover the study of various parameters such as the concentration of dissolved dioxygen or the energy of the incident radiation leads us to propose a new mechanism on the origin of the radiosensitizing effect. Nevertheless, biological applications of GNP can only be considered if the nano-objects are functionalized to make them furtive, address them or deliver medicines to the tumor. After synthesis and characterization of different functionalized GNP, we compared hydroxyl radicals production with the damages induced on DNA and highlighted a significant impact of functionalization on the radiosensitizing effect. Finally, this work gives valuable information for the design of the most efficient GNP for radiotherapy which is a first step towards their medical application
Bigan, Bertrand. "Technique de photolyse-laser-flourescence de résonance : mise en place et application à l'étude cinétique des réactions du radical hydroxyle avec l'éthane, l'isobutène, l'isoprène et le cyclohexène." Lille 1, 1993. http://www.theses.fr/1993LIL10106.
Повний текст джерелаShamas, Mirna. "Study of the reactivity of radical species of peroxyl type of atmospheric interest." Electronic Thesis or Diss., Université de Lille (2022-....), 2022. http://www.theses.fr/2022ULILR036.
Повний текст джерелаIn the atmosphere, organic pollutants such as Volatile Organic Compounds (VOCs) from biogenic or anthropogenic sources are oxidized by OH radicals leading to the formation of peroxy radicals RO2 and HO2, which play a major role in tropospheric chemistry. Their reactivity controls the oxidative capacity of the atmosphere (cycling of reactive radicals) and the formation of tropospheric ozone and other secondary pollutants. While the reactivity of these peroxy radicals is well known in polluted environments (high NOX concentrations), it is still poorly known in a remote environments containing low concentrations of NOx (ex: tropical forests, marine boundary layer).The aim of the present work is to study the kinetics of some of these peroxy radicals to better understand the radical + radical reactions in clean atmosphere. Two experimental set-ups have been used. First a fast discharge flow reactor, originally designed to complement an existing photolysis cell set-up, was continued to be developed in the frame of this work. This fast flow reactor is coupled to three complementary techniques: the continuous-wave Cavity Ring-Down Spectroscopy (cw-CRDS) for the measurement of the HO2 radical, the Laser Induced Fluorescence (LIF) for the detection of the OH radical and Mass spectrometry with Molecular Beam sampling (MB/MS) for the measurement of stable reaction products and radical species. An unexplained OH reformation phenomenon has been observed in the previous work done during the validation of this recently developed experimental set-up. In this work, different tests were carried out to explain this OH reformation phenomenon and will be described here. Meanwhile a laser photolysis cell coupled to a double cw-CRDS paths for the simultaneous measurements of RO2 and HO2 radicals was used to determine the absorption cross-section of C2H5O2 radical, the rate constant of C2H5O2 + HO2, and the rate constant and branching ratios for the C2H5O2 self-reaction
Shamas, Nesrine. "Understanding of atmospheric and indoor air chemistry through HOx radical measurements." Electronic Thesis or Diss., Université de Lille (2022-....), 2023. http://www.theses.fr/2023ULILR057.
Повний текст джерелаHOx (OH+HO2) and RO2 radicals are involved in oxidation processes in the gas phase, generating secondary products impacting the air quality and human health. Understanding these oxidation processes through the quantification of these radicals is still challenging because of their low concentrations (
Thiébaud, Jérôme. "Développement d'un spectromètre à cavité optique de haute finesse couplé à la photolyse laser : mesures spectroscopiques et cinétiques du radical HO2." Lille 1, 2007. https://pepite-depot.univ-lille.fr/LIBRE/Th_Num/2007/50376-2007-Thiebaud.pdf.
Повний текст джерелаBresson, Alexandre. "Techniques d'imagerie quantitatives : fluorescence induite par laser appliquée aux écoulements et aux combustions." Rouen, 2000. http://www.theses.fr/2000ROUES065.
Повний текст джерелаFaider, Wilfrid. "Traitement de l'acétaldéhyde par décharges électriques impulsionnelles dans les mélanges de gaz atmosphériques : cinétique et efficacité énergétique." Phd thesis, Université Paris Sud - Paris XI, 2013. http://tel.archives-ouvertes.fr/tel-00804682.
Повний текст джерелаSaffré, Dimitri. "Radiolyse de l’eau dans des conditions extrêmes de température et de TEL. Capture de HO• par les ions Br-." Thesis, Paris 11, 2011. http://www.theses.fr/2011PA112246/document.
Повний текст джерелаThe purpose of this thesis is to contribute to the understanding of the oxidation mechanism of Br- in which the HO• radical is involved. The HO• radiolytic yield is strongly connected with the oxidation yield of Br-, and therefore we have studied the influence of different physical and chemical parameters on this global yield: temperature, LET, dose rate, pH, saturation gas. The solutions have been irradiated with 4 types of ionizing rays: X- rays (from 13 to 18 keV), electrons (from 7 to 10 MeV), C6+-ions beam of 975 MeV and He2+-ions beam of 70 MeV.The development of an optical autoclave with solution flow, compatible with high LET ionizing rays has allowed us conduct the first experiments at constant high LET and high temperature. This cell has turned out to be compatible with the picosecond pump-probe experiments performed with the ELYSE accelerator.The HO• scavenging yield has been, therefore, estimated at both high LET and high temperature. A better understanding of the Br- oxidation mechanism has been achieved, in acid medium, in particular, by comparing the kinetics results with Monte Carlo Simulations for time scales inferior to the microsecond and with Chemsimul for the stable products (Br2•- and Br3- formations)
Trabelsi, Souhaila. "Etudes de traitement des lixiviats des déchets urbains par les procédés d’oxydation avancée photochimiques et électrochimiques : application aux lixiviats de la décharge tunisienne "Jebel Chakir"." Thesis, Paris Est, 2011. http://www.theses.fr/2011PEST1122/document.
Повний текст джерелаPas de résumé en anglais
Lin, Heng. "Removal of organic pollutants from water by electro-Fenton and electro-Fenton like processes." Thesis, Paris Est, 2015. http://www.theses.fr/2015PEST1058/document.
Повний текст джерелаIn this paper, electro-Fenton and sulfate radical-based electro-Fenton-like processes were used to degrade artificial sweeteners and azo dye. The results obtained during the research concern the removal efficiency, the oxidation mechanism, degradation pathway and toxicity evolution of target pollutants.(1) Electro-Fenton process was a effective method for the degradation of ASP in water. The removal and mineralization rate was affected by the Fe2+ concentration and applied current. The absolute rate constant of hydroxylation reaction of ASP was (5.23 ± 0.02) × 109 M–1 S–1. Short-chain aliphatic acids such as oxalic, oxamic and maleic acid were identified as aliphatic intermediates in the electro-Fenton process. The bacteria luminescence inhibition showed the toxicity of ASP solution decreased after it reached a maximum during the first period of the oxidation reaction.(2) Artificial sweetener SAC could be degraded effectively by electro-Fenton process with a DSA, Pt or BDD anode. However, the using of BDD anode could accelerate the mineralization of SAC. The optimal conditions for SAC removal were SAC concentration 0.2 mM, Fe2+ concentration 0.2 mM, Na2SO4 concentration 50 mM, applied current 200 mA and initial pH 3.0. Oxalic, formic, and maleic acid were observed as aliphatic byproducts of SAC during electro-Fenton process. The bacteria luminescence inhibition showed the toxicity of SAC solution increased at the beginning of electrolysis, and then it declined until the end of the reaction.(3) Artificial sweetener Sucralose could be completely mineralized in a 360 min reaction by electro-Fenton process with a Pt or BDD anode. The mineralization rate was affected by the Fe2+ concentration and applied current. The mineralization current efficiency (MCE) decreased with rising applied current from 100 to 500 mA with both Pt and BDD anode. Oxalic, pyruvic, formic and glycolic acids were detected during the oxidation of sucralose.(4) Orange II was effectively decolorized by EC/α-FeOOH/PDS process. The initial pH of Orange II solution had little effect on the decolorization of Orange II. RSM based on Box-Behnken statistical experiment design was applied to analyze the experimental variables. The response surface methodology models were derived based on the results of the pseudo-first-order decolorization rate constant and the response surface plots were developed accordingly. The results indicated the applied current showed a positive effect on the decolorization rate constant of Orange II. The interaction of α-FeOOH dosage and PDS concentration was significant. The ANOVA results confirmed that the proposed models were accurate and reiable for the analysis of the varibles of EC/α-FeOOH/PDS process. The catalystα-FeOOH showed good structural stability and could be reused.(5) Aqueous solutions of Orange II have been degraded effectively in the EC/Fe3O4/PDS process. The decolorization rate was affected by the initial pH of Orange II solution, current density, PDS concentration and Fe3O4 dosage. Orange II can be totally decolorizated in a 60 min reaction when initial Orange II concentration was 25 mg/L, PDS concentration was 10 mM, Fe3O4 dosage was 0.8 g/L, current density was 8.4 mA/cm2 and initial pH was 6.0. Recycle experiments showed Fe3O4 particles were stable and can be reused. XPS spectrum indicated Fe(II) was generated on the surface of Fe3O4 particles after reaction. The main intermediates were separated and identified by GC-MS technique and a plausible degradation pathway of Orange II was proposed
Akin, Myles. "Site specific thermodynamic study of OH radical addition to DNA bases." Thesis, Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/33919.
Повний текст джерелаArlie, Natacha. "Réactivité de radicaux inorganiques, CO3 *- et Cl*/Cl2 *- en solution aqueuse." Phd thesis, Université Blaise Pascal - Clermont-Ferrand II, 2012. http://tel.archives-ouvertes.fr/tel-00973851.
Повний текст джерелаMiet, Killian. "Etude expérimentale de la dégradation hétérogène des Composés Aromatiques Polycycliques (CAP) d'intérêt troposphérique." Phd thesis, Bordeaux 1, 2008. http://tel.archives-ouvertes.fr/tel-00424794.
Повний текст джерелаJolibois, Franck. "Etude théorique de lésions radioinduites de l'ADN : analyses conformationnelles, propriétés électroniques et mécanismes de formation." Université Joseph Fourier (Grenoble), 1997. http://www.theses.fr/1997GRE10157.
Повний текст джерелаSmith, Mathew D. "Reaction of hydroxyl radical with aromatic systems." Virtual Press, 2008. http://liblink.bsu.edu/uhtbin/catkey/1399191.
Повний текст джерелаDepartment of Chemistry
Kurzyp, Magdalena. "Hydrogenated nanodiamond as radiosensitizer : chemical and physical investigations of the involved mechanisms." Thesis, Université Paris-Saclay (ComUE), 2017. http://www.theses.fr/2017SACLN060/document.
Повний текст джерелаAmong all nanocarbons, detonation nanodiamonds (NDs) possess outstanding chemical and physical properties suitable for bio-applications. Well-controlled mass production provides NDs with a primary size of 5 nm made of a diamond-core and a shell-coating containing various surface terminations. Surface chemistry of NDs can be tuned via thermal or plasma treatments providing either positively or negatively charged NDs in water suspension. Our group recently showed that plasma hydrogenated NDs (H-NDs) behave a radiosensitizing effect on radioresistant cancer cell lines providing potential therapeutic abilities as radiosensitizing agents. Nevertheless, the mechanisms involved behind this effect are not currently well understood. The main goal of this PhD is to study the behaviour of NDs suspended in water under ionizing radiations (X-ray and Gamma) and to investigate the production of reactive oxygen species (ROS), in particular hydroxyl radicals (HO). Additional experiments allow to detect also produced solvated electrons (eaq). The detection of HO radicals and solvated electrons was realized in the presence of a fluorescence probe, the 7 OH-coumarin, under various atmospheres (air and N2O/O2). Starting from the same source of NDs, different surface chemistries were compared (oxidized, hydrogenated and surface graphitized). In parallel, colloidal properties and stability of these modified NDs in water with respect to their surface chemistry were investigated at short and long term. An overproduction of HO was observed for H-NDs for both hydrogenation methods and vacuum annealed NDs at 750°C. In addition, the production of solvated electrons was confirmed for H-NDs. These results were discussed taking into account the surface chemistry, the colloidal stability and specific interactions of water molecules with NDs
Lajoie, Halova Barbora. "Complexation du cuivre(II) avec des dérivés de l'acide anthranilique dans les conditions physiologiques et implications potentielles de ces complexes dans le processus inflammatoire." Toulouse 3, 2005. http://www.theses.fr/2005TOU30216.
Повний текст джерелаOur search for an nonsteroidal antiinflammatory drug is based on presence of the endogenous copper, combined with easily oxidizible ligands. We studied the methoxylated and hydroxylated derivatives of the acid anthranilic. First of all, we determined the complexes with Cu(II) at 37°C and NaCl 0. 15 M. The presence of the species was confirmed by the mass spectrometry. The catalysis of the Fenton reaction was evaluated by redox potential measurements of Cu(II)/Cu(I) in the presence of the ligands. Lastly, we tested the reactivity of the species towards •OH with degradation test of deoxyribose. The methoxylated ligands have a low affinity for Cu(II) under physiological conditions. At inflammatory pH (pH 5. 5) they become predominant ligands of Cu(II), supporting the Fenton reaction and scavenging the formed radicals. The hydroxylated ligands prevent the formation of •OH at inflammatory conditions, but at pH 7. 4, they tend to auto-oxidize
Dolgorouky, Cristina. "Mesure de la réactivité atmosphérique totale avec les radicaux hydroxyles (OH) : développement et applications en Ile-de-France." Phd thesis, Université Paris Sud - Paris XI, 2012. http://tel.archives-ouvertes.fr/tel-00684758.
Повний текст джерелаMitroka, Susan M. "Modulation of Hydroxyl Radical Reactivity and Radical Degradation of High Density Polyethylene." Diss., Virginia Tech, 2010. http://hdl.handle.net/10919/77137.
Повний текст джерелаPh. D.
Ledoux, Valentin. "Matériaux nanocomposites à base d'oxydes conducteurs pour la génération d'énergie électrique en milieux humides et pour de nouvelles applications électrocatalytiques." Thesis, IMT Mines Alès, 2019. http://www.theses.fr/2019EMAL0002.
Повний текст джерелаAn "Unusual" behavior of oxide anodes in aqueous media, compared with metal anodes, began to attract the attention of researchers as early as the 1960s. During the activation process, electrons placed in the valence band (VB) of a semiconductor material leave their energy level and move towards the conduction band (CB) thereby forming electronic holes able to proceed at the direct oxidation of adsorbed hydroxyl anions, thereby transforming them into hydroxyl radicals HO•, which are extremely powerful oxidizing agents. This consideration makes it possible to explain why the oxidation of organic pollutants in water is always higher on the oxide anodes than on the metal anodes. The reaction cycle is as follows:H2O + MOx ["Catalytic" site] MOx•HO•ads + H+ + 1 e- then MOx•HO•ads + RH MOx + H2O + R’Although widely used in electrocatalysis water depollution processes, the mechanism describing the interactions between oxide anodes and water is poorly understood.The ambition of this thesis is to demonstrate the feasibility of recovering electrical charges from water using a metal oxide anode, SnO2:F was chosen as the model anode. The demonstration of this hypothesis follows 5 steps: 1. Understand why water is able to behave as a reducing agent and therefore share its electric charge with external consumers through metal oxide surfaces. 2.Conceptualize the mode of action of oxide anodes in humid environments. Develop a clear vision on the mechanism of this phenomenon, study it in detail and objectively confirm its main stages through experimental results. 3.Conceptualize, from the point of view of chemical compositions as well as physicochemical and electro-physical properties, promising active materials applicable as generators of elementary electrical charges from wetlands. 4.Choose, develop and test appropriate active materials, that is to say, meet the requirements, in terms of chemical compositions and electro-physical properties, fixed in the previous point. 5.Conclude by the proposal of a method of estimating the energy efficiency of the process under development and the prospects of applications
Mattei, Coraline. "Réactivité hétérogène de pesticides adsorbés sur des particules atmosphériques : influence des paramètres environnementaux sur les cinétiques." Thesis, Aix-Marseille, 2019. http://www.theses.fr/2019AIXM0181.
Повний текст джерелаEnvironmental contamination by pesticides is ubiquitous and induces health and environmental impacts. Once applied, some of the pesticides reach the atmosphere, where they distribute between the aqueous, gaseous and particle phases. Most of the currently used pesticides are semi-volatiles and are therefore partially adsorbed on the atmospheric particle surfaces and undergo heterogeneous degradation reactions. If their reactivity in the gaseous phase is often known, their reactivity in the particle phase remains poorly described. This experimental work allowed studying the influence of environmental parameters (relative humidity, type of particles, pesticides surface concentration) on the reactivity of eight pesticides (cyprodinil, deltamethrin, difenoconazole, fipronil, oxadiazon, pendimethalin, permethrin, tetraconazole). They were adsorbed on mineral surfaces mimicking mineral aerosol particles (hydrophobic and hydrophilic silica, Arizona sand) to simulate atmospheric degradation by the mains atmospheric oxidants (ozone, hydroxyl radicals (OH) and nitrate radicals (NO3)). Results showed that relative humidity, particle type, and pesticide concentration can influence the heterogeneous degradation of pesticides with ozone and OH radicals. They also showed the efficiency of NO3 radicals for the atmospheric heterogeneous degradation of pesticides (half-lives in the particle phase from 2 to 16 d with NO3 compared to 0.4 to > 800 d with ozone and to 3 to > 100 d with OH). Results obtained allow a better understanding of the atmospheric fate of pesticides and will contribute to predict of atmospheric contamination
Nitisha, Hiranandani. "Impact of Reperfusion Injury on Heart." The Ohio State University, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=osu1239720273.
Повний текст джерелаLenton, K. J. "Hydroxyl radical scavengers and antioxidants in radiation protection." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp02/NQ32339.pdf.
Повний текст джерелаMcKay, Garrett J. "Reactivity of the hydroxyl radical with organic matter." Thesis, California State University, Long Beach, 2014. http://pqdtopen.proquest.com/#viewpdf?dispub=1527332.
Повний текст джерелаThe goal of this study was to investigate some of the fundamental chemistry of the reactions between the hydroxyl radical and apply this knowledge to the treatment of chemical contaminants in real world waters. To accomplish this goal, the techniques of electron pulse radiolysis were used to quantify second-order rate constants for the reaction between the HO· radical and well characterized OM samples. Studies of HO· radical reactivity with model polyethylene glycol polymers were performed to help understand OM-HO· reactivity. Experiments using steady state radiolysis were performed in order to assess the effect of long-term, seasonal variability in OM composition on the degradation of probe compounds used as model chemical contaminants. In addition, the photochemical production of HO· from OM sensitization was also investigated.
Black, Helen Dinah. "Kinetics of hydroxyl radical reactions with heterocyclic compounds." Thesis, University of Leeds, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.305373.
Повний текст джерелаAsuru, Awuri P. "Applications of X-ray Hydroxyl Radical Protein Footprinting." Case Western Reserve University School of Graduate Studies / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=case1575877091577049.
Повний текст джерелаDahlstrom, Stephen W. "Hydroxyl radical activity in bleached root-filled teeth /." Title page, contents and summary only, 1992. http://web4.library.adelaide.edu.au/theses/09DM/09dmd131.pdf.
Повний текст джерелаHamdi, El Najjar Nasma. "Cinétiques et mécanismes d'oxydation de composés pharmaceutiques par le chlore, l'ozone et les radicaux hydroxyle." Thesis, Poitiers, 2012. http://www.theses.fr/2012POIT2264/document.
Повний текст джерелаRecently, the presence of pharmaceuticals in the aquatic environment has been reported as an emerging environmental issue. Actually, numerous pharmaceuticals have been detected in surface waters. Chlorination, ozonation and oxidation by hydroxyl radicals are widely used in water treatment due to their disinfectant and oxidation properties. However, these oxidationprocesses can induce refractory transformation products. In this context, the objective of this work was to study the fate of three commonly used pharmaceuticals (metronidazole, paracetamol and levofloxacin) during oxidation with chlorine, ozone and hydroxyl radicals. First, a kinetic study was conducted at pH 7.2 and 20°C and rate constants were determined. For each pharmaceutical, different rates of degradation were observed depending on oxidation process. To better assess pharmaceutical removal under water treatment conditions, an estimation of pharmaceutical removal under several oxidation conditions (i.e.oxidant concentrations, contact time, water quality) was undertaken. In a second part, numerous transformation products were identified by LC/MS and LC/MS/MS and reactional pathways were suggested. Finally, monitoring of the toxicity (luminescence inhibition of Vibrio fisheri) were performed and compared to the formation of by-products. An increase in toxicity was observed for each oxidation process and pharmaceutical tested for the smallest oxidant doses
Barreto, Joao Pedro Cabaco Moniz. "Dioxygen free radical reactions." Thesis, Oxford Brookes University, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.389105.
Повний текст джерелаMorin, Julien. "Etudes expérimentales des réactions des radicaux OH et des atomes d’oxygène d’intérêt pour l’atmosphère et la combustion." Thesis, Orléans, 2016. http://www.theses.fr/2016ORLE2034/document.
Повний текст джерелаThe objective of this work was to study the reactions of alkyl nitrates with OH radicals relevant to atmosphere and reactions of OH radical with alkanes and oxygen atoms with olefins of interest for combustion chemistry. All reactions were studied in low pressure flow reactors (including high temperature flow reactor developed during the thesis) coupled to a quadrupole mass spectrometer with electron impact ionization. For OH reaction with nitrates, the temperature dependence of the rate constant was measured in an extended temperature range for ten alkyl nitrates, for eight of them for the first time. For six nitrates, the products of reaction pathway leading to direct recycling of NO₂ (H atom abstraction from α carbon) were observed and their yields were measured. The large amount of data obtained in this work has been used for an update of the structure-activity relation (SAR) for the reactions of alkyl nitrates with OH and will improve existing atmospheric models. For the reactions of OH radicals with three alkanes and O atoms with ethene and propene the rate constants were measured over a wide temperature range, 220-900 K. Moreover, the distribution of the products of the multichannel reactions O + olefin was determined as a function of temperature for the first time. These results are expected to improve current combustion models
Özcan, Ali. "Degradation of hazardous organic compounds by using electro-fenton technology." Phd thesis, Université Paris-Est, 2010. http://tel.archives-ouvertes.fr/tel-00601213.
Повний текст джерела