Relevant bibliographies by topics / Selective oxidation model

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  1. Journal articles
  2. Dissertations / Theses
  3. Book chapters
  4. Conference papers
  5. Reports

Academic literature on the topic 'Selective oxidation model'

Author: Grafiati
Published: 3 June 2022

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Journal articles on the topic "Selective oxidation model"

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Gao, Ruili, Yanding Li, Hoon Kim, Justin K. Mobley, and John Ralph. "Selective Oxidation of Lignin Model Compounds." ChemSusChem 11, no. 13 (May 30, 2018): 2045–50. http://dx.doi.org/10.1002/cssc.201800598.

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Gomez, Jean-Marc, Laurent Gil, Clotilde Ferroud, Alice Gateau-Olesker, Marie-Thérèse Martin, and Christian Marazano. "Selective Oxidation of a Keramaphidin B Model." Journal of Organic Chemistry 66, no. 14 (July 2001): 4898–903. http://dx.doi.org/10.1021/jo015680i.

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Căldăraru, H., G. Filoti, R. Mănăilă, M. Căldăraru, N. I. Ionescu, M. Selenina, and K. H. Schnabel. "Model Phases for Selective Oxidation and Ammoxidation." Zeitschrift für Physikalische Chemie 177, Part_1 (January 1992): 75–92. http://dx.doi.org/10.1524/zpch.1992.177.part_1.075.

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Laperdrix, E., G. Costentin, N. Nguyen, F. Studer, and J. C. Lavalley. "Study of H2S selective oxidation on new model catalysts." Catalysis Today 61, no. 1-4 (August 2000): 149–55. http://dx.doi.org/10.1016/s0920-5861(00)00363-1.

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Hess, Christian. "Nanostructured Vanadium Oxide Model Catalysts for Selective Oxidation Reactions." ChemPhysChem 10, no. 2 (February 2, 2009): 319–26. http://dx.doi.org/10.1002/cphc.200800585.

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Chen, Yueying, Aiguo Xue, Haomin Jiang, Yujuan Cheng, Yuan Ren, Yanzhi Sun, and Yongmei Chen. "A two-phase reaction system for selective oxidative degradation of lignin model compounds." BioResources 15, no. 3 (July 8, 2020): 6526–38. http://dx.doi.org/10.15376/biores.15.3.6526-6538.

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Lignin depolymerization through an oxidation method could provide value-added products, but it is challenging in terms of recovering catalysts or separating products in time to avoid over-oxidation. In this study, a process of selectively oxidative degradation of lignin model compounds was operated in a two-phase reaction system. Lignin model compounds of 4-benzyloxyphenol (PBP) or guaiacylglycerol-β-guaiacyl ether (GGE) in a bottom phase of 1-butyl-3-methylimidazole chloride ([BMIM]Cl) ionic liquid were selectively oxidized by H2O2 in the presence of a solid acid (SO42-/Fe2O3-ZrO2), and the degradation products immediately diffused into the upper organic solvent phase (butyl acetate). In this kind of reaction system, the yield of the products was improved due to the prolonged life of ∙OH in ionic liquid, and the product selectivity was maintained due to the timely product separation, and the ionic liquid and the catalyst were easily recycled.
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Filipek, Robert. "Modelling of Interdiffusion and Reactions at the Boundary; Initial-Value Problem of Interdiffusion in the Open System." Defect and Diffusion Forum 237-240 (April 2005): 250–56. http://dx.doi.org/10.4028/www.scientific.net/ddf.237-240.250.

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The application of the Danielewski-Holly model of interdiffusion for modelling of selective and concurrent oxidation of multi-component alloys is presented. This model enables prediction of the evolution of components distributions taking into account interdiffusion and the reactions at the boundary, e.g, due to the oxidation/sulphidation processes. The model is subsequently reformulated to the form suitable for numerical calculation. For illustrating its capabilities modelling of the selective oxidation of Ni-Pt alloys is presented. The results are compared with those obtained from Wagner model. Both models give exactly the same results for the longer reaction times. In Wagner model the equilibrium concentration of the elements at the boundary is reached instantly while in this model it changes with time. Consequently the model allows modelling of initial stages of oxidation.
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Corberán, Vicente Cortés, Almudena Gómez-Avilés, Susana Martínez-González, Svetlana Ivanova, María I. Domínguez, and María Elena González-Pérez. "Heterogeneous selective oxidation of fatty alcohols: Oxidation of 1-tetradecanol as a model substrate." Catalysis Today 238 (December 2014): 49–53. http://dx.doi.org/10.1016/j.cattod.2014.03.033.

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Chan-Thaw, Carine, Aditya Savara, and Alberto Villa. "Selective Benzyl Alcohol Oxidation over Pd Catalysts." Catalysts 8, no. 10 (September 30, 2018): 431. http://dx.doi.org/10.3390/catal8100431.

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In the last decades, the selective liquid phase oxidation of alcohols to the corresponding carbonyl compounds has been a subject of growing interest. Research has focused on green methods that use “clean” oxidants such as O2 in combination with supported metal nanoparticles as the catalyst. Among the alcohols, benzyl alcohol is one of the most studied substrates. Indeed, benzyl alcohol can be converted to benzaldehyde, largely for use in the pharmaceutical and agricultural industries. This conversion serves as model reaction in testing new potential catalysts, that can then be applied to other systems. Pd based catalysts have been extensively studied as active catalytic metals for alcohol oxidation for their high activity and selectivity to the corresponding aldehyde. Several catalytic materials obtained by careful control of the morphology of Pd nanoparticles, (including bimetallic systems) and by tuning the support properties have been developed. Moreover, reaction conditions, including solvent, temperature, pressure and alcohol concentration have been investigated to tune the selectivity to the desired products. Different reaction mechanisms and microkinetic models have been proposed. The aim of this review is to provide a critical description of the recent advances on Pd catalyzed benzyl alcohol oxidation.
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Al-Hunaiti, Afnan, Batool Abu-Radaha, Darren Wraith, and Timo Repo. "Catalytic behaviour of the Cu(i)/L/TEMPO system for aerobic oxidation of alcohols – a kinetic and predictive model." RSC Advances 12, no. 13 (2022): 7864–71. http://dx.doi.org/10.1039/d1ra09359b.

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Here, we disclose a new copper(i)-Schiff base complex series for selective oxidation of primary alcohols to aldehydes under benign conditions. Both benzylic and aliphatic alcohols were converted to aldehydes selectively with 99% yield.
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Dissertations / Theses on the topic "Selective oxidation model"

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Zhou, Ling. "Model studies of methanol selective oxidation over copper catalysts." [S.l. : s.n.], 2005. http://deposit.ddb.de/cgi-bin/dokserv?idn=976146614.

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Walter, Anke [Verfasser], and Thorsten [Akademischer Betreuer] Ressler. "Spectroscopic and catalytic investigations of VxOy/SBA-15 and magnesium vanadate model catalysts for selective propene oxidation / Anke Walter. Betreuer: Thorsten Ressler." Berlin : Universitätsbibliothek der Technischen Universität Berlin, 2011. http://d-nb.info/1017839816/34.

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Parezanović, Ivana. "Selective oxidation and segregation in commercial steels and model alloys (tools for improving the surface wettability by liquid Zn during hot dip galvanizing)." [S.l.] : [s.n.], 2005. http://deposit.ddb.de/cgi-bin/dokserv?idn=979088933.

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Kühn, Sven [Verfasser], Thorsten [Akademischer Betreuer] Ressler, Thorsten [Gutachter] Ressler, and Peter [Gutachter] Strauch. "Structure-function relationships of molybdenum-based oxide nitrides as model catalysts in selective oxidation of propene / Sven Kühn ; Gutachter: Thorsten Ressler, Peter Strauch ; Betreuer: Thorsten Ressler." Berlin : Technische Universität Berlin, 2016. http://d-nb.info/1156346630/34.

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Agrizzi, Ronqueti Larissa. "Study of grain boundary oxidation of high alloyed carbon steels at coiling temperature." Thesis, Compiègne, 2018. https://bibliotheque.utc.fr/Default/doc/SYRACUSE/2018COMP2405.

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Les aciers à haute résistance (AHSS) ont été largement utilisés dans le cadre d’applications automobiles visant à améliorer la sécurité et l’allègement des structures. Afin d'atteindre les objectifs en termes de propriétés mécaniques, ces nouveaux aciers sont composés de teneurs en éléments d’alliages beaucoup plus élevés (par exemple silicium et manganèse) que les aciers usuels. En conséquence, l'AHSS est susceptible de subir une oxydation interne sélective lors du refroidissement des bobines d’acier. L'oxydation sélective interne, en particulier l'oxydation aux joints de grains (GBO), est actuellement l'un des principaux obstacles à la production de ces aciers. Elle réduit le nombre de cycles avant la rupture de fatigue et rend ainsi difficile l’obtention des spécifications du client. Par conséquent, ce travail de thèse était axé sur l'effet de plusieurs paramètres sur le comportement à l’oxydation interne sélective. Parmi eux, l'impact de la décarburation, l'influence de la température de bobinage et de la couche de calamine, l'effet de différentes teneurs en silicium et / ou en manganèse et leur comportement en diffusion. De plus, l'impact de la désorientation des joints de grains sur l'oxydation interne a également été étudié. Des alliages modèles à base de fer binaires / ternaires ainsi que des aciers industriels ont été étudiés via un large ensemble de techniques expérimentales. Ces analyses ont mis en évidence une décarburation stable pour tous les échantillons étudiés qui n'a pas d'impact sur l'oxydation interne sélective pour une longue exposition aux conditions isothermes. Les profondeurs d’oxydation aux joints de grain ont été examinées selon les différentes configurations de tests et se sont révélées sensibles aux teneurs en silicium ou en manganèse. Pour certaines d'entre elles, différents comportements de diffusion du silicium ont été identifiés vis-à-vis de l'oxydation des joints de grains, en fonction des températures. Considérant quelques hypothèses restrictives, l'application de la théorie de l'oxydation interne sélective de Wagner a permis de déterminer le coefficient de diffusion de l'oxygène aux joints de grain. Pour surmonter certaines limites du modèle de Wagner, un modèle d'oxydation sélective a été appliqué pour comprendre l'effet de différents paramètres sur la pénétration de l'oxygène à l'intérieur du métal et principalement sur la profondeur des joints de grain affectée par l'oxydation sélective. Les connaissances acquises à partir de ce travail de thèse aideront à comprendre et à limiter l'oxydation sélective interne (principalement l’oxydation aux joints de grain) dans les aciers avec des compositions complexes en éléments d’alliage. En outre, les résultats peuvent être utilisés pour évaluer les paramètres d’un modèle d'oxydation sélective
Advanced high-strength steels (AHSS) have been widely used in automotive industry to improve safety and fuel economy. In order to reach the mechanical properties targets, these new steels are composed by much higher alloy contents (e.g. silicon and manganese) than usual steels. As consequence, the AHSS may suffer of selective internal oxidation during the cooling of hot coil. The selective internal oxidation, especially the grain boundary oxidation (GBO), is currently one of the main obstacles to the production of these steels. It reduces the number of cycles before fatigue failure and thus, makes it difficult to reach the specifications of the customer. Therefore, this PhD work was focused on the effect of several parameters on selective internal oxidation behavior. Among them, the impact of decarburization, the influence of coiling temperature and the mill scale, the effect of different silicon and/or manganese contents and their diffusion behavior. Moreover, the impact of grain boundary misorientation on grain boundary oxidation was also investigated. Either binary/ternary iron-based model alloys as well as industrial steels were investigated by a large set of experimental techniques. This analysis showed a stable decarburization for all investigated samples that does not impact the selective internal oxidation for long exposure time in isothermal conditions. The GBO depths were examined according to the different test configurations and were found dependent for some cases on silicon or manganese content. For some of them, different silicon diffusion behaviors were identified with regards to grain boundary oxidation depending on temperatures. Considering some restrictive hypotheses, the application of Wagner’s theory of selective internal oxidation allowed determining the grain boundary diffusion coefficient of oxygen. To overcome some limitations of Wagner’s model, a model of selective oxidation has been applied to understand the effect of different parameters on the penetration of oxygen inside the metal and principally on the grain boundary depth affected by selective oxidation. The knowledge acquired from this PhD work will help to understand and limit the selective internal oxidation (mainly GBO) in new steels with complex alloy compositions. Furthermore, the results may be used to assess a model of selective oxidation
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Patil, Nikhil Dilip. "A STUDY OF LIGNIN DEPOLYMERIZATION BY SELECTIVE CLEAVAGE OF THE Cα-Cβ LINKAGES IN LIGNIN MODEL COMPOUNDS VIA BAEYER-VILLIGER OXIDATION & AN INVESTIGATION OF THE CHANNELING REACTION IN NITROGEN-DOPED MULTIWALLED CARBON NANOTUBES (N-MWCNTS)." UKnowledge, 2014. http://uknowledge.uky.edu/chemistry_etds/43.

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A STUDY OF LIGNIN DEPOLYMERIZATION BY SELECTIVE CLEAVAGE OF THE Cα-Cβ LINKAGES IN LIGNIN MODEL COMPOUNDS VIA BAEYER-VILLIGER OXIDATION Lignin is amorphous aromatic polymer derived from plants and is a potential source of fuels and bulk chemicals. Herein, we present a survey of reagents for selective stepwise oxidation of lignin model compounds. Specifically, we have targeted the oxidative cleavage of Cα-Cβ bonds as a means to depolymerize lignin and obtain useful aromatic compounds. In this work, we prepared several lignin model compounds that possess structures, characteristic reactivity, and linkages closely related to the parent lignin polymer. We observed that selective oxidation of benzylic hydroxyl groups using TEMPO/O2, followed by Baeyer-Villiger oxidation of the resulting ketones using H2O2, successfully cleaves the Cα-Cβ linkage in the model compounds. This process was also applied to depolymerization of Organosolv lignin. The deconstructed lignin was analyzed by a number of techniques, including ATR-IR, GPC, and 31P NMR of suitably derivatized samples. AN INVESTIGATION OF THE CHANNELING REACTION IN NITROGEN-DOPED MULTIWALLED CARBON NANOTUBES (N-MWCNTS) The reduction of nitrogen-doped multiwalled carbon nanotubes (N-MWCNTs) with Li/NH3 results in deep longitudinal cuts in the nanotubes structure. As the N-MWCNTs are anisotropic, we were able to investigate whether the unzipping process proceeds with equal efficiency from the tip end or from the root (catalyst) end of the N-MWCNT structure. To accomplish this we prepared polymer filled aligned arrays of N-MWCNTs, then exposed one or the other end. Through this approach we were able to shield the sidewalls and either end of the nanotubes from the Li/NH3 solution We have found that when the top end of the N-MWCNTs array was exposed to the reaction mixture, very few nanotubes suffered significant ‘unzipping’. However, when the root (substrate) side of the array is exposed to the reaction mixture, we observe the features characteristic of nanotubes with longitudinal cuts. Our finding provides some insight into the mechanism of the unzipping process, and provides evidence that the unzipping process has a directional preference-unzipping from the root end towards the tip end. And may provide a method for selective functionalization of the interior of tubes and create a new form of nanotube- based porous membrane.
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Lee, Jiwon. "Novel fabrication of Alloy 625 and MCrAlY bond coat by laser powder bed fusion and microstructure control A novel approach to the production of NiCrAlY bond coat onto IN625 superalloy by selective laser melting Influence of heat treatments on microstructure evolution and mechanical properties of Inconel 625 processed by laser powder bed fusion A new observation of strain-induced grain boundary serration and its underlying mechanism in a Ni–20Cr binary model alloy Heat treatments design for superior high-temperature tensile properties of Alloy 625 produced by selective laser melting High temperature oxidation of NiCrAlY coated Alloy 625 manufactured by selective laser melting." Thesis, Ecole nationale des Mines d'Albi-Carmaux, 2020. http://www.theses.fr/2020EMAC0008.

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Dans cette étude, l'alliage 625 a été élaboré par l'une des méthodes de fabrication additive (AM) les plus couramment utilisées, la fusion laser sélective sur lit de poudre (L-PBF), et ses propriétés mécaniques ont été évaluées à différentes températures. L'alliage 625 fabriqué par L-PBF a montré une résistance élevée et un allongement à la rupture médiocre. Ainsi, des traitements thermiques ont été appliqués pour améliorer ses performances. Un traitement thermique de mise en solution à une température supérieure à 1000 °C a été appliquée à l'alliage L-PBF 625, ce qui a entraîné une recristallisation en raison de l’énergie stockée par le matériau attribuée à la forte densité de dislocations présentes dans l’alliage. Cette microstructure modifiée a montré une résistance satisfaisante lors des essais de traction à température ambiante (résistance plus élevée que l'alliage corroyé 625 et allongement supérieur à l'alliage L-PBF brut de fabrication). À l'étape suivante, l'alliage L-PBF 625 recristallisé a été soumis à un traitement thermique de Grain Boundary Serration (GBS, dentelure des joints de grains) pour améliorer ses propriétés mécaniques à haute température. Comme il s'agissait de la première tentative pour générer la GBS d'un alliage à haute teneur en Nb, il était d'abord important de comprendre le mécanisme GBS. Pour induire le GBS, il est nécessaire que les larges atomes de soluté se déplacent près des joints de grains (GB). Par conséquent, le traitement thermique GBS a été modifié pour être appliqué à l'alliage L-PBF 625. Le traitement thermique de GBS spécialement conçu a réussi à induire pour la première fois les motifs en zigzag des GB dentelés. Cet alliage GB-L-PBF dentelé 625 a montré des propriétés mécaniques améliorées à haute température en termes de ductilité accrue et d'élimination de l'effet de vieillissement dynamique (DSA). Pour améliorer davantage les propriétés à haute température de l'alliage L-PBF 625, un revêtement de liaison NiCrAlY a été nouvellement appliqué au substrat en alliage 625 par la même méthode (L-PBF) pour améliorer l'efficacité du processus de production et augmenter la résistance à l'oxydation/corrosion à haute température. Bien que leurs différentes propriétés thermiques aient conduit à de nombreux essais et erreurs dans la fabrication du matériau, les paramètres optimaux ont été définis et vérifiés pour évaluer le potentiel de commercialisation du procédé. La caractéristique de refusion du L-PBF a induit une bonne liaison entre le substrat et le revêtement, ce qui indique une bonne stabilité. Le comportement à l'oxydation de l'alliage 625 revêtu de NiCrAlY a été caractérisé par analyse thermo-gravimétrique (TGA) et des tests de chocs thermiques ; les résultats ont indiqué que le nouveau matériau avait une résistance à l'oxydation plus élevée que l'alliage 625 brut de fabrication. Par conséquent, le traitement thermique de GBS associé à un revêtement NiCrAlY efficace peut améliorer considérablement les propriétés mécaniques à haute température de l'alliage 625 fabriqué par L-PBF
In this study, Alloy 625 was fabricated by one of the most commonly used additive manufacturing (AM) methods, laser powder bed fusion (L-PBF), and its mechanical properties were evaluated at various temperatures. The L-PBF fabricated Alloy 625 showed high strength and relatively poor elongation. Thus, some heat treatments were applied to improve its performance. A solid-solution heat treatment with a temperature of more than 1000 °C was applied to the L-PBF Alloy 625, resulting in recrystallization because of high energy stored within the alloy attributed by high density of dislocations. This modified microstructure of the L-PBF Alloy 625 sample showed the required strength under tensile testing at room temperature (higher strength than wrought Alloy 625 and greater elongation than L-PBF as-built alloy). In view of enhancing mechanical properties at high temperature, a grain boundary serration (GBS) heat treatment was specifically designed for L-PBF Alloy 625. Because this was the first attempt to produce GBS in a high-Nb-content alloy, it was necessary to understand its mechanism first. To induce GBS, it is necessary for large solute atoms to move near the grain boundaries (GBs). Therefore, the GBS heat treatment was modified for application to the L-PBF Alloy 625. The specially designed GBS heat treatment successfully induced the zigzag patterns of serrated GBs for the first time. This GBS L-PBF Alloy 625 showed improved high-temperature mechanical properties in terms of increased ductility and elimination of the dynamic strain aging (DSA) effect at elevated temperatures. To further improve the high-temperature property of the L-PBF Alloy 625, NiCrAlY bond coat was applied to the Alloy 625 substrate by the same method (L-PBF) for the first time to improve the efficiency of the production process and increase the resistance to oxidation. Although their different thermal properties led to many trials and errors in the manufacturing of the material, the optimal parameters for applying NiCrAlY bond coat deposition by L-PBF were set and verified to assess the potential for the process to be commercialized. The remelting characteristic of L-PBF induced good metallurgical bonding between the substrate and coating, which indicates good stability. The oxidation behavior of the NiCrAlY-coated Alloy 625 was characterized by thermal gravimetric analysis (TGA) and thermal shock testing; the results indicated that the novel coated material had higher resistance to oxidation than bulk Alloy 625. Therefore, the GBS heat treatment together with efficient NiCrAlY coating can greatly improve the high-temperature mechanical properties of L-PBF manufactured Alloy 625
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Chen, Wei-Ching. "Selective Oxidation of Lignin Models and Extracts with Earth-Abundant Transition Metals and Hypervalent Iodine." Thesis, Université d'Ottawa / University of Ottawa, 2015. http://hdl.handle.net/10393/32181.

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As a significant component of lignocellulosic biomass, lignin represents a potential source of value-added aromatic chemicals. In this thesis, catalytic systems with earth-abundant metal catalysts such as molybdenum(VI) and hypervalent iodine complexes were developed to selectively break down lignin models into lower molecular weight chemicals under mild conditions. Due to the complexity of lignin, simple lignin model substrates (A to E), representing common linkages in lignin, were used to investigate the catalytic activity/selectivity of these catalysts. With the molybdenum catalysts [7– 11]/SPC/Adogen®464 system (SPC = sodium percarbonate), oxidation of simple β-1 model compound A in acetonitrile showed primarily C-H bond cleavage to form the ketone product, benzoin methyl ether, whereas the Cα-Cβ bond cleavage product, methyl benzoate, was obtained by switching the reaction solvent to benzonitrile. Preference for generating the Cα-Cβ bond cleavage product, i.e. benzaldehyde, can also be achieved with other early to middle transition metal catalysts using H2O2(aq) as the terminal oxidant. Stoichiometric amounts of hypervalent iodine/Lewis acid systems [20a-c] were able to selectively cleave Cα-Cβ bonds to aldehydes with both simple β-1 model compound A and β-O-4 model compound C. In contrast, other lignin model compounds with different linkages were unable to be oxidized to a great extent using these Mo- or iodine-based complexes. The catalytic activity and selectivity of the reported vanadium complexes, copper salts and non-metal system 1-5 on non-volatile organosolv (NVO) lignin was investigated under basic condition. Details of the depolymerisation of lignin were determined by using Gel Permeation Chromatography (GPC) and the two-dimensional NMR technique, quantitative HSQC (q-HSQC) spectroscopy. Vanadium [2] and copper systems were found to be the most active for depolymerization of NVO lignin.
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Messant, Benoît. "Conception, réalisation et caractérisation de diodes laser InGaAsN/GaAs à diaphragme d'oxyde pour les télécommunications optiques à 1,3μm." Toulouse 3, 2006. http://www.theses.fr/2006TOU30256.

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Les travaux reportés dans cette thèse concernent la conception et la réalisation technologique d'une diode laser à puits quantiques InGaAsN émettant à 1,3μm, épitaxiée sur substrat de GaAs, et comportant une structure à ruban à base d'un diaphragme d'oxyde d'aluminium (Alox). Nous présentons, tout d'abord, l'étude de modélisation et de conception de ces diodes laser. En nous appuyant sur un outil incluant la modélisation de la structure de bande des puits quantiques InGaAsN/GaAs, une étude complète d'optimisation des propriétés d'émission des puits quantiques est menée. Nous en dégageons les critères de conception de la structure bidimensionnelle pour obtenir une émission laser à 1,3μm présentant de bonnes performances en terme de stabilité thermique et de réponse dynamique, compatible avec les réseaux optiques d'accès. La seconde partie porte sur la réalisation technologique des composants. Nous présentons la mise au point de l'étape d'oxydation latérale humide et au développement d'un procédé technologique complet et reproductible de réalisation de diodes laser avec injection latérale des porteurs et diaphragme d'oxyde en tenant compte des contraintes technologiques des différentes étapes du procédé. La réalisation et la caractérisation de diodes laser à diaphragme d'oxyde ont constitué la dernière phase de ce travail. Après avoir validé le procédé technologique dans la filière AlGaAs/GaAs, nous avons procédé à une caractérisation approfondie des composants à multi puits quantiques InGaAsN/GaAs afin d'évaluer les potentialités de cette nouvelle filière et de confirmer l'intérêt du confinement procuré par le diaphragme Alox pour l'obtention de composants monomodes stables
The works reported in this thesis concern the study of a multiple quantum well (QW) InGaAsN laser diode emitting at 1. 3μm, grown on GaAs substrate, and comprising a ridge structure obtained by a selective lateral thermal wet oxidation of an AlAs layer (Alox). First of all, a complete optimization study of the properties of the InGaAsN QW emission is carried out. This study uses a model based on the band structure modelling of InGaAsN. We deduce the parameters of two-dimensional structural design to obtain a 1. 3μm laser emission wavelength, presenting good thermal stability and high dynamic response compatible with the optical access networks. In the second time, after the development of the selective wet oxidation process, we present a complete and reproducible technological realization process of ridge laser diodes with side injection of the carriers and oxide diaphragm by taking account of the technological constraints of the various stages. The realization and the characterization of laser diodes constituted the last part of this work. After validating the technological process in the AlGaAs/GaAs material system, we carry out a comprehensive characterization of the components including 3QW InGaAsN active layers in order to evaluate the potentialities of this new material system and to confirm the interest of the lateral confinement by oxide layers to obtain stable single-mode components
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Zhou, Ling [Verfasser]. "Model studies of methanol selective oxidation over copper catalysts / von Ling Zhou." 2005. http://d-nb.info/976146614/34.

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Book chapters on the topic "Selective oxidation model"

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Calingasan, Noel Y., Kwan-Fu Rex Sheu, Harriet Baker, Samuel E. Gandy, and Gary E. Gibson. "Thiamine Deficiency as a Model of Selective Neurodegeneration with Chronic Oxidative Deficits." In Neurodegenerative Diseases, 193–201. Boston, MA: Springer US, 1996. http://dx.doi.org/10.1007/978-1-4899-0209-2_25.

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Kutyrev, M. Yu, I. N. Staroverova, N. Z. Thiep, and O. V. Krylov. "The Model of Active Centers for Partial Oxidation in The Structure of Heteropoly Compounds." In New Developments in Selective Oxidation, 869–79. Elsevier, 1990. http://dx.doi.org/10.1016/s0167-2991(08)60222-0.

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Ziolkowski, J., E. Bordes, and P. Courtine. "A Dynamic Model of The Oxidation of n-Butane and 1-Butene on Various Crystalline Faces of (VO)2P2O7." In New Developments in Selective Oxidation, 625–33. Elsevier, 1990. http://dx.doi.org/10.1016/s0167-2991(08)60194-9.

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Witko, Malgorzata, and Klaus Hermann. "Selective Hydrocarbon Oxidation at Vanadium Pentoxide Surfaces: Ab Initio Cluster Model Studies." In New Developments in Selective Oxidation II, Proceedings of the Second World Congress and Fourth European Workshop Meeting, 75–81. Elsevier, 1994. http://dx.doi.org/10.1016/s0167-2991(08)63399-6.

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McCarty, J. G., A. B. McEwen, and M. A. Quinlan. "Models of The Direct Catalytic Partial Oxidation of Light Alkanes." In New Developments in Selective Oxidation, 405–15. Elsevier, 1990. http://dx.doi.org/10.1016/s0167-2991(08)60172-x.

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Skibida, I. P., and A. M. Sakharov. "Perspectives in Improvement of Selectivity In Liquid Phase Oxidation by Dioxygen. New Models of Enzymatic Oxidation." In New Developments in Selective Oxidation, 221–28. Elsevier, 1990. http://dx.doi.org/10.1016/s0167-2991(08)60152-4.

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Taber, Douglass F. "The Herzon Synthesis of (−)-Acutumine." In Organic Synthesis. Oxford University Press, 2017. http://dx.doi.org/10.1093/oso/9780190646165.003.0085.

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The alkaloid (−)-acutumine 3, isolated from the roots of the Chinese moonseed Sinomenium acutum, improves object and social recognition in the Wistar rat model. With four rings and three adjacent, fully-substituted stereogenic centers, 3 presents a significant synthetic challenge. Seth B. Herzon of Yale University assembled (Angew. Chem. Int. Ed. 2013, 52, 3642) 3 by the intramolecular Sakurai cyclization of 1 to 2. The convergent preparation of 1 required the alkyne 10. The literature construc­tion (Org. Lett. 2005, 7, 5075) by A. B. Smith III of the enone 7 from ribose 4 began with protection to 5. Conversion of the primary alcohol to the iodide followed by reduction delivered the aldehyde 6. Addition of vinyl magnesium bromide followed by exposure to the first- generation Grubbs catalyst gave the cyclopentenol, that was oxidized to 7. Conjugate silylation led to the triflate 8, that was carried via coupling with 9 to 10. In earlier work, Professor Herzon had shown (Angew. Chem. Int. Ed. 2011, 50, 8863) that the prochiral quinone from oxidation of 11 could be added to the diene 12 under enantioselective catalysis, to give 13 in high ee. Reduction of the azide gave the imine, that was quaternized with methyl triflate. Addition of the Li salt of 10 to that sensitive intermediate proceeded with high facial selectivity. With aromatiza­tion blocked, the product from the addition of 10 could be thermolyzed to yield 14. The stannylation of the alkyne proceeded with high regio- and stereoselectivity, to give the alkene 1. Exposure of the allylic silane to tetrabutylammonium fluoride drove the desired cyclization to give 2. Chlorination followed by acetonide removal then completed the preparation of the diol 15. The completion of the synthesis required extensive experimentation. Eventually, a protocol was established to oxidize 15 over several steps to the dienone 16. Selective reduction of the ketone (the other carbonyls are vinylogous esters) proceeded with the desired facial selectivity, to give 17. Selective hydrogenation using a Rh catalyst then delivered (−)-acutumine 3. This is the second total synthesis of (−)-acutumine 3. The first, by Steven L. Castle of Brigham Young University (OHL October 5, 2009), is quite different. It is instruc­tive to compare the two side by side.
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Julião, Diana, Susana Ribeiro, Baltazar de Castro, Luís Cunha-Silva, and Salete S. Balula. "Polyoxometalates-Based Nanocatalysts and Their Efficiency for Production of Sulfur-Free Diesel." In Nanocomposites for the Desulfurization of Fuels, 92–133. IGI Global, 2020. http://dx.doi.org/10.4018/978-1-7998-2146-5.ch004.

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Polyoxometalates have been demonstrated to be efficient catalysts for the activation of oxidants in desulfurization processes. Successful results on desulfurization using polyoxometalates and hydrogen peroxide to desulfurize model oils and liquid fuels were reported and can be found in the literature. The desulfurization is an actual subject with notable interest for refineries and fuel cost, and consequently, it is important to focus the scientific community to work in desulfurization technology in order to develop catalytic systems based on polyoxometalates capable to be reused, stable, efficient, and selective. Therefore, the main goal is the design of heterogeneous polyoxometalate based catalysts. This chapter pretends to inform the research society about the scientific directions that have been taken using heterogeneous polyoxometalate catalysts in oxidative desulfurization of simulated and real liquid fuels. In addition, future perspectives are proposed to cover the actual needs of this area.
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Royo, Miriam, and George Barany. "Preparation and handling of peptides containing methionine and cysteine." In Fmoc Solid Phase Peptide Synthesis. Oxford University Press, 1999. http://dx.doi.org/10.1093/oso/9780199637256.003.0008.

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Among the genetically encoded amino acid residues, methionine (Met) and cysteine (Cys) are special because they each contain an atom of sulphur. The present chapter describes how these residues are incorporated into peptides in the context of an Fmoc/tBu solid-phase synthesis strategy, as well as further considerations once the synthetic peptide is released from the support. Of added interest, some manipulations of Cys are advantageously performed at the level of the assembled peptide-resin, prior to cleavage. Many of the aspects discussed here also carry over to the preparation of peptides using a Boc/Bzl strategy. The major problems associated with management of Met reflect the susceptibility of the thioether to alkylation and oxidation. One of the merits of the Fmoc/tBu strategy, in contrast to Boc/Bzl, is that in the former strategy Met is usually introduced without recourse to a protecting group for the thioether side-chain. As documented in this chapter, a proper understanding of acidolytic cleavage conditions and the availability of selective procedures to reverse any inadvertent oxidation are likely to lead to success in obtaining homogeneous peptides containing Met. Management of Cys provides additional significant challenges. For some targets, Cys is required with its side-chain in the free thiol form, whereas for other targets, an even number of Cys residues pair with each other via disulphide linkage(s) to provide cystine residue(s). Disulphide bridges play an important role in the folding and structural stabilization of many natural peptides and proteins, and their artificial introduction into natural or designed peptides is a useful approach to improve biological activities/specificities and stabilities. Furthermore, use of a disulphide bridge is a preferred method to conjugate peptides to protein carriers for increasing the response in immuno-logical studies, to link two separate chains for developing discontinuous epitopes, and to generate active site models. This chapter describes Cys protecting groups, how they are removed to provide either free thiols or disulphides directly, and various strategies and practical considerations to minimize side reactions and maximize formation of the desired products. The thioether side-chain of Met is subject to alkylation and oxidation side reactions, either during the synthetic process or during subsequent handling of the Met-containing peptide.
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Julião, Diana, Susana Ribeiro, Baltazar de Castro, Luís Cunha-Silva, and Salete S. Balula. "Polyoxometalates-Based Nanocatalysts for Production of Sulfur-Free Diesel." In Applying Nanotechnology to the Desulfurization Process in Petroleum Engineering, 426–58. IGI Global, 2016. http://dx.doi.org/10.4018/978-1-4666-9545-0.ch014.

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In the last decade, polyoxometalates have been demonstrated to be efficient catalysts for the activation of oxidants in desulfurization processes. Successful results on desulfurization using polyoxometalates and hydrogen peroxide to desulfurize model oils and liquid fuels were reported and can be found in the literature. The desulfurization is an actual subject with notable interest for refineries and fuel cost, and consequently it is important to focus the scientific community to work in desulfurization technology in order to develop catalytic systems based on polyoxometalates capable to be reused, stable, efficient and selective. Therefore, the main goal is the design of heterogeneous polyoxometalate based catalysts. This chapter pretends to inform the research society about the scientific directions that have been taken using heterogeneous polyoxometalate catalysts in oxidative desulfurization of simulated and real liquid fuels. In addition, future perspectives are proposed to cover the actual needs of this area.
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Conference papers on the topic "Selective oxidation model"

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Devarakonda, Maruthi, Russell Tonkyn, Diana Tran, Jong Lee, and Darrell Herling. "Modeling Species Inhibition of NO Oxidation in Urea-SCR Catalysts for Diesel Engine NOx Control." In ASME 2010 Internal Combustion Engine Division Fall Technical Conference. ASMEDC, 2010. http://dx.doi.org/10.1115/icef2010-35054.

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Urea-selective catalytic reduction (SCR) catalysts are regarded as the leading NOx aftertreatment technology to meet the 2010 NOx emission standards for on-highway vehicles running on heavy-duty diesel engines. However, issues such as low NOx conversion at low temperature conditions still exist due to various factors, including incomplete urea thermolysis, inhibition of SCR reactions by hydrocarbons and H2O. We have observed a noticeable reduction in the standard SCR reaction efficiency at low temperature with increasing water content. We observed a similar effect when hydrocarbons are present in the stream. This effect is absent under fast SCR conditions where NO ∼ NO2 in the feed gas. As a first step in understanding the effects of such inhibition on SCR reaction steps, kinetic models that predict the inhibition behavior of H2O and hydrocarbons on NO oxidation are presented in the paper. A one-dimensional SCR model was developed based on conservation of species equations and was coded as a C-language S-function and implemented in Matlab/Simulink environment. NO oxidation and NO2 dissociation kinetics were defined as a function of the respective adsorbate’s storage in the SCR catalyst. The corresponding kinetic models were then validated on temperature ramp tests that showed good match with the test data.
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Hsieh, Ming-Feng, and Junmin Wang. "A Physically-Based, Control-Oriented Diesel Particulate Filter (DPF) Model for the Applications of NO/NO2 Ratio Estimation Using a NOx Sensor." In ASME 2010 Dynamic Systems and Control Conference. ASMEDC, 2010. http://dx.doi.org/10.1115/dscc2010-4011.

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This paper presents a physically-based, control-oriented Diesel particulate filter (DPF) model for the purposes of NO and NO2 concentration estimations in Diesel engine aftertreatment systems. The presence of NO2 in exhaust gas plays an important role in selective catalytic reduction (SCR) NOx reduction efficiency. However, current NOx cannot differentiate NO and NO2 from the total NOx concentration. A model which can be used to estimate NO and NO2concentrations in exhaust gas flowing into the SCR catalyst is thus necessary. Current aftertreatment systems for light-, medium-, and heavy-duty Diesel engines generally include Diesel oxidation catalyst (DOC), DPF, and SCR. The DPF related NO/NO2 dynamics was investigated in this study, and a control-oriented model was developed and validated with experimental data.
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Hsieh, Ming-Feng, and Junmin Wang. "A Physically-Based, Control-Oriented Diesel Oxidation Catalyst (DOC) Model for the Applications of NO/NO2 Ratio Estimation Using a NOx Sensor." In ASME 2010 Dynamic Systems and Control Conference. ASMEDC, 2010. http://dx.doi.org/10.1115/dscc2010-4010.

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NO and NO2 are generally considered together as NOx in engine emissions. Since NO2/NOx ratio is small in diesel engine exhaust gas, very often, existence of NO2 is ignored in studies/applications. However, current diesel aftertreatment systems generally include diesel oxidation catalysts (DOCs) at upstream of other catalysts such as diesel particulate filter (DPF) and selective catalytic reduction (SCR). DOC can significantly increase the NO2 fraction in the exhaust NOx. Because NO2 and NO have completely different reaction characters within catalysts, e.g. NO2 can assist DPF regeneration while NO cannot, and SCR De-NOx rate can be increased with higher NO2/NOx ratio (no more than 0.5), considerations of NO2 in aftertreatment systems are becoming necessary. Nevertheless, current onboard NOx sensors cannot differentiate NO and NO2 from NOx. This induces an interest in the method of estimating the concentrations of NO and NO2 in the exhaust gas by available measurements. In this paper, a physically-based, DOC control-oriented model which considers the NO and NO2 related dynamics and an engine exhaust NO/NO2 prediction method were proposed for the purposes of NO/NO2 ratio estimation in diesel engine aftertreatment systems, and the developed model was validated with experimental data.
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Chen, Pingen, and Junmin Wang. "Oxygen Concentration Dynamic Model Through a Diesel Engine Aftertreatment System." In ASME 2011 Dynamic Systems and Control Conference and Bath/ASME Symposium on Fluid Power and Motion Control. ASMEDC, 2011. http://dx.doi.org/10.1115/dscc2011-6035.

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This paper presents a control-oriented model describing the dynamics of oxygen concentration through a Diesel engine aftertreatment system that includes a Diesel oxidation catalyst (DOC) and a Diesel particulate filter (DPF). Exhaust gas oxygen concentration is important for catalysts such as NOx conversion efficiencies of selective catalytic reduction (SCR) systems and lean NOx traps (LNT). In the presence of low-pressure loop exhaust gas recirculation (EGR), the exhaust gas oxygen concentration after-DPF also influences combustion. Due to the chemical reactions occurring inside DOC and DPF, the exhaust gas oxygen concentration considerably varies through the aftertreatment systems. Directly measuring the exhaust gas oxygen concentrations at different locations through the exhaust gas aftertreatment system is costly and unreliable. A dynamic model is thus needed in order to design model-based observers to estimate the exhaust gas oxygen concentrations at various locations. The oxygen-related reactions within a DOC and a DPF are investigated in this study. A lumped-parameter, control-oriented DOC-DPF oxygen concentration dynamic model was developed by a multi-objective optimization method and validated with experimental data obtained on a medium-duty Diesel engine equipped with full aftertreatment systems. Experimental results show that the model can well capture the oxygen dynamics across the Diesel engine aftertreatment systems.
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Luo, Zhaoyu, Parvez Sukheswalla, Scott A. Drennan, Mingjie Wang, and P. K. Senecal. "3D Numerical Simulations of Selective Catalytic Reduction of NOx With Detailed Surface Chemistry." In ASME 2017 Internal Combustion Engine Division Fall Technical Conference. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/icef2017-3658.

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Environmental regulations have put stringent requirements on NOx emissions in the transportation industry, essentially requiring the use of exhaust after-treatment on diesel fueled light and heavy-duty vehicles. Urea-Water-Solution (UWS) based Selective Catalytic Reduction (SCR) for NOx is one the most widely adopted methods for achieving these NOx emissions requirements. Improved understanding and optimization of SCR after-treatment systems is therefore vital, and numerical investigations can be employed to facilitate this process. For this purpose, detailed and numerically accurate models are desired for in-cylinder combustion and exhaust after-treatment. The present paper reports on 3-D numerical modeling of the Urea-Water-Solution SCR system using Computational Fluid Dynamics (CFD). The entire process of Urea injection, evaporation, NH3 formation and NOx reduction is numerically investigated. The simulation makes use of a detailed kinetic surface chemistry mechanism to describe the catalytic reactions. A multi-component spray model is applied to account for the urea evaporation and decomposition process. The CFD approach also employs an automatic meshing technique using Adaptive Mesh Refinement (AMR) to refine the mesh in regions of high gradients. The detailed surface chemistry NOx reduction mechanism validated by Olsson et al. (2008) is applied in the SCR region. The simulations are run using both transient and steady-state CFD solvers. While transient simulations are necessary to reveal sufficient details to simulate catalytic oxidation during transient engine processes or under cyclic variations, the steady-state solver offers fast and accurate emission solutions. The simulation results are compared to available experimental data, and good agreement between experimental data and model results is observed.
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Sidwell, Vince, and David Darmofal. "A Selective Assembly Method to Reduce the Impact of Blade Flow Variability on Turbine Life." In ASME Turbo Expo 2004: Power for Land, Sea, and Air. ASMEDC, 2004. http://dx.doi.org/10.1115/gt2004-53930.

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A selective assembly method is proposed that decreases the impact of blade passage manufacturing variability on the life of a row of cooled turbine blades. The method classifies turbine blades into groups based on the effective flow areas of the blade passages, then a row of blades is assembled exclusively from blades of a single group. A simplified classification is considered in which blades are divided into low-flow, nominal-flow, and high-flow groups. For rows assembled from the low-flow class, the blade plenum pressure will tend to rise and the individual blade flows will be closer to the design intent than for a single low-flow blade in a randomly-assembled row. Since the blade metal temperature is strongly dependent on the blade flow, selective assembly can lower the metal temperature of the lowest-flowing blades and increase the life of a turbine row beyond what is possible from a randomly-assembled row. Furthermore, the life of a nominal-flow or high-flow row will be significantly increased (relative to a randomly-assembled row) since the life-limiting low-flow blades would not be included in these higher-flowing rows. The impact of selective assembly is estimated using a model of the first turbine rotor of an existing high-bypass turbofan. The oxidation lives of the nominal-flow and high-flow blade rows are estimated to increase approximately 50% and 100% compared to randomly-assembled rows, while the life of the low-flow rows are the same as the randomly-assembled rows. Alternatively, selective assembly can be used to increase turbine inlet temperature while maintaining the maximum blade metal temperatures at random-assembly levels. For the nominal-flow and high-flow classes, turbine inlet temperature increases are estimated to be equivalent to the turbine inlet temperature increases observed over several years of gas turbine technology development.
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Beil, Alexander, and Joerg R. Seume. "Unsteady Performance of a PEMFC System Including Autothermal Methane Reforming." In ASME 2006 4th International Conference on Fuel Cell Science, Engineering and Technology. ASMEDC, 2006. http://dx.doi.org/10.1115/fuelcell2006-97008.

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A zero-dimensional, dynamic model of a PEM fuel cell with an autothermal methane reformer section is generated. In the model, reformer consists of three reactors for the autothermal steam reforming, the water gas shift, and the selective oxidation. Physical approaches are favored over empirical modeling equations in order to describe the relevant transport phenomena. Thus, in spite of the low order modeling, only physical parameters are required for the input. The aim of the model is the calculation of the cell voltage for a given set of geometrical and thermodynamic data including the current density. The fuel cell water management is modeled with equations for the water transport through the membrane by electro-osmotic drag and diffusion as well as the membrane humidity. Flooding due to liquid water content and dehydration of the membrane is simulated dynamically with this model. These critical conditions are identified by the cell voltage. Due to pressure feedback, dynamic simulations show partial pressure fluctuation in the reformer reactors caused by load changes of the fuel cell.
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Upadhyay, Devesh, and Michiel Van Nieuwstadt. "Control Design of an Automotive Urea SCR Catalyst." In ASME 2002 International Mechanical Engineering Congress and Exposition. ASMEDC, 2002. http://dx.doi.org/10.1115/imece2002-32103.

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The leading aftertreatment technologies for NOx removal from the exhaust gas of lean burn engines, Diesels in particular, are urea based Selective Catalytic Reduction (SCR), Lean NOx Traps (LNT) and Active Lean NOx Catalysts (ALNC). It is generally believed that the SCR technique has the potential of providing the best NOx conversion efficiency relative to the other techniques. Nonetheless, it is crucial that the high conversion efficiencies be achieved with a minimum slippage of unreacted ammonia as tail pipe emissions. This necessitates a precise control over the urea injection process. The complex behavior of the catalyst substrate with respect to adsorption and desorption of ammonia in conjunction with a lack of “stored ammonia” sensing capabilities makes the control problem challenging. In this paper we present a model-based control design approach using a lumped parameter model of an SCR system that includes the essential dynamics of the plant. The model includes the adsorption, desorption and surface coverage dynamics, along with the NOx reduction and ammonia oxidation dynamics based on the relevant chemical reaction rates.
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Hsieh, Ming-Feng, and Junmin Wang. "Observer-Based Estimation of Diesel Engine Aftertreatment System NO and NO2 Concentrations." In ASME 2010 Dynamic Systems and Control Conference. ASMEDC, 2010. http://dx.doi.org/10.1115/dscc2010-4045.

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This paper presents an observer design for Diesel engine aftertreatment system NO and NO2 concentrations estimations. NO and NO2 have different reaction characteristics within SCR systems. Current production NOx sensors cannot differentiate NO and NO2. Such an observer thus can be used by selective catalytic reduction (SCR) system control and diagnosis purposes. Diesel oxidation catalyst (DOC) and Diesel particulate filter (DPF) were considered as the catalysts which can affect NO/NO2 fraction of the exhaust gas upstream of the SCR. The observer was designed based on an experimentally-validated control-oriented dynamic model which can accurately represent the NO and NO2 dynamics from engine-out, through DOC, and to DPF. Stability of the observer was theoretically proved through a Lyapunov analysis assisted by insight into the system characteristics. The effectiveness of the observer was shown by comparing the estimated NO and NO2 concentrations with the measured ones by a Horiba emissions measurement system.
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Calvez, S., G. Lafleur, C. Arlotti, A. Larrue, P. F. Calmon, A. Arnoult, G. Almuneau, and O. Gauthier-Lafaye. "III-V-semiconductor vertically-coupled whispering-gallery mode resonators made by selective lateral oxidation." In SPIE LASE, edited by Alexis V. Kudryashov, Alan H. Paxton, and Vladimir S. Ilchenko. SPIE, 2016. http://dx.doi.org/10.1117/12.2210968.

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Reports on the topic "Selective oxidation model"

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Watkins, Chris B., Susan Lurie, Amnon Lers, and Patricia L. Conklin. Involvement of Antioxidant Enzymes and Genes in the Resistance Mechanism to Postharvest Superficial Scald Development. United States Department of Agriculture, December 2004. http://dx.doi.org/10.32747/2004.7586539.bard.

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The objective of this research project was to evaluate the involvement of antioxidant enzymes and genes in the resistance mechanism to postharvest superficial scald development using two primary systems: 1. Resistant and susceptible progenies of an apple cross between a scald resistant crab apple, ‘White Angel’ and a scald susceptible cultivar, ‘Rome Beauty’; 2. Heat-treatment of ‘Granny Smith’, which is known to reduce scald development in this cultivar. In 2002 we asked for, and received (October 14), permission to revise our initial objectives. The US side decided to expand their results to include further work using commercial cultivars. Also, both sides wanted to include an emphasis on the interaction between these antioxidant enzymes and the á-farnesene pathway, with the cooperation of a third party, Dr. Bruce Whitaker, USDA-ARS, Beltsville. Background: Superficial scald is a physiological storage disorder that causes damage to the skin of apple and pear fruit. It is currently controlled by use of an antioxidant, diphenylamine (DPA), applied postharvest by drenching or dips, but concern exists about such chemical usage especially as it also involves application of fungicides. As a result, there has been increased emphasis on understanding of the underlying mechanisms involved in disorder development. Our approach was to focus on the oxidative processes that occur during scald development, and specifically on using the two model systems described above to determine if the levels of specific antioxidants and/or antioxidant enzyme activities correlated with the presence/absence of scald. It was hoped that information about the role of antioxidant-defense mechanisms would lead to identification of candidate genes for future transgenic manipulation. Major conclusions, solutions, achievements: Collectively, our results highlight the complexity of superficial scald developmental processes. Studies involving comparisons of antioxidant enzyme activities in different crab apple selection, commercial cultivars, and in response to postharvest heat and 1-methylcyclopropene (1-MCP) treatments, show no simple direct relationships with antioxidant contents and susceptibility of fruit to scald development. However, a correlative relationship was found between POX activity or isoenzyme number and scald resistance in most of the studies. This relationship, if confirmed, could be exploited in breeding for scald resistance. In addition, our investigations with key genes in the á-farnesenebiosynthetic pathway, together with antioxidant processes, are being followed up by analysis of exposed and shaded sides of fruit of cultivars that show different degrees of scald control by 1-MCP. These data may further reveal productive areas for future research that will lead to long term control of the disorder. However, given the complexity of scald development, the greatest research need is the production of transgenic fruit with down-regulated genes involved in á- farnesene biosynthesis in order to test the currently popular hypothesis for scald development.
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Fluhr, Robert, and Maor Bar-Peled. Novel Lectin Controls Wound-responses in Arabidopsis. United States Department of Agriculture, January 2012. http://dx.doi.org/10.32747/2012.7697123.bard.

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Innate immune responses in animals and plants involve receptors that recognize microbe-associated molecules. In plants, one set of this defense system is characterized by large families of TIR–nucleotide binding site–leucine-rich repeat (TIR-NBS-LRR) resistance genes. The direct interaction between plant proteins harboring the TIR domain with proteins that transmit and facilitate a signaling pathway has yet to be shown. The Arabidopsis genome encodes TIR-domain containing genes that lack NBS and LRR whose functions are unknown. Here we investigated the functional role of such protein, TLW1 (TIR LECTIN WOUNDRESPONSIVE1). The TLW1 gene encodes a protein with two domains: a TIR domain linked to a lectin-containing domain. Our specific aim in this proposal was to examine the ramifications of the TL1-glycan interaction by; A) The functional characterization of TL1 activity in the context of plant wound response and B) Examine the hypothesis that wounding induced specific polysaccharides and examine them as candidates for TL-1 interactive glycan compounds. The Weizmann group showed TLW1 transcripts are rapidly induced by wounding in a JA-independent pathway and T-DNA-tagged tlw1 mutants that lack TLW1 transcripts, fail to initiate the full systemic wound response. Transcriptome methodology analysis was set up and transcriptome analyses indicates a two-fold reduced level of JA-responsive but not JA-independent transcripts. The TIR domain of TLW1 was found to interact directly with the KAT2/PED1 gene product responsible for the final b-oxidation steps in peroxisomal-basedJA biosynthesis. To identify potential binding target(s) of TL1 in plant wound response, the CCRC group first expressed recombinant TL1 in bacterial cells and optimized conditions for the protein expression. TL1 was most highly expressed in ArcticExpress cell line. Different types of extraction buffers and extraction methods were used to prepare plant extracts for TL1 binding assay. Optimized condition for glycan labeling was determined, and 2-aminobenzamide was used to label plant extracts. Sensitivity of MALDI and LC-MS using standard glycans. THAP (2,4,6- Trihydroxyacetophenone) showed minimal background peaks at positive mode of MALDI, however, it was insensitive with a minimum detection level of 100 ng. Using LC-MS, sensitivity was highly increased enough to detect 30 pmol concentration. However, patterns of total glycans displayed no significant difference between different extraction conditions when samples were separated with Dionex ICS-2000 ion chromatography system. Transgenic plants over-expressing lectin domains were generated to obtain active lectin domain in plant cells. Insertion of the overexpression construct into the plant genome was confirmed by antibiotic selection and genomic DNA PCR. However, RT-PCR analysis was not able to detect increased level of the transcripts. Binding ability of azelaic acid to recombinant TL1. Azelaic acid was detected in GST-TL1 elution fraction, however, DHB matrix has the same mass in background signals, which needs to be further tested on other matrices. The major findings showed the importance of TLW1 in regulating wound response. The findings demonstrate completely novel and unexpected TIR domain interactions and reveal a control nexus and mechanism that contributes to the propagation of wound responses in Arabidopsis. The implications are to our understanding of the function of TIR domains and to the notion that early molecular events occur systemically within minutes of a plant sustaining a wound. A WEB site (http://genome.weizmann.ac.il/hormonometer/) was set up that enables scientists to interact with a collated plant hormone database.
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