Tesis sobre el tema "Lay catalysis"

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1

Naudon, Frederic. "Analyses sociologique et expérimentale de la contribution de profanes-néophytes à la démocratie technique : le déploiement d’une filière hydrogène-énergie en Normandie". Electronic Thesis or Diss., Normandie, 2022. http://www.theses.fr/2022NORMC038.

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Une personne n’ayant pas de connaissances particulières dans un domaine — i.e. un profane-néophyte — est-elle capable d’aider un spécialiste de ce domaine à produire de nouvelles connaissances ? Cette question trouve son origine dans le croisement de deux champs disciplinaires : l’étude des effets de la vulgarisation scientifique sur les chercheurs qui vulgarisent leur propre sujet d’études et les recherches sur les dispositifs de démocratie technique de type conférence de citoyens. De nombreuses traces tangibles de pertinence de la part du « grand public » et des citoyens « ordinaires », principalement sous forme de témoignages, laissent penser que la rencontre avec des profanes-néophytes peut constituer une ressource cognitive originale. Pour explorer cette question, nous étudions la relation entre le(s) spécialiste(s) d’un domaine et des non-spécialistes de ce domaine.La première modalité de recherche est une enquête qualitative auprès des acteurs du déploiement d’une filière hydrogène-énergie en Normandie (observations directes, entretiens et analyse de documents-clés). La seconde repose sur des dispositifs expérimentaux visant à confirmer ou infirmer l’idée que les profanes-néophytes peuvent être des acteurs de la réflexion aux côtés des spécialistes, dans deux contextes réputés pour leur complexité : la recherche scientifique (réunions de laboratoire intégrant des profanes-néophytes) et l’implantation d’une nouvelle technologie dans un territoire (réunions interdisciplinaires pour le projet d’un bateau-école électrique à hydrogène dans un lycée maritime). Ce travail montre qu’un profane-néophyte possède une capacité à penser libre de certains freins liés à la connaissance du sujet et qu’il est ainsi en mesure de donner de la mobilité au spécialiste par rapport à son sujet. Le facteur limitant est du côté du spécialiste dont la posture, en particulier l’humilité et l’ouverture à l’autre, joue un rôle déterminant
Is a person with no particular knowledge in a field – i.e. a layperson-neophyte – able to help a specialist in that field to produce new knowledge? This question originates from the intersection of two disciplinary fields: the study of the effects of scientific popularization on researchers who popularize their own subject of study and research on technical democracy devices such as citizen conferences. Many obvious traces of relevance from the general public and "ordinary" citizens, mainly in the form of testimonials, suggest that encounters with laypersons-neophytes can be an original cognitive resource. To explore this question, we study the relationship between field specialist(s) and non-specialists of the same field.The first research method is a qualitative survey of the actors involved in the deployment of a hydrogen-energy sector in Normandy (direct observations, interviews and analysis of key documents). The second method is based on experimental devices aiming at confirming or disproving the idea that laypersons-neophytes can be actors of reflection alongside specialists, in two contexts renowned for their complexity: scientific research (laboratory meetings integrating laypersons-neophytes) and the implementation of a new technology in a territory (interdisciplinary meetings about the project of an electric hydrogen training-boat in a professional fishing school). This work shows that a layperson-neophyte possesses a capacity to think clear of specific brakes linked to the knowledge of the subject. It shows also that the layperson is able to give the specialist more mobility in relation to his subject. The limiting factor is on the side of the specialist’s responsibility: his approach, particularly with humility and openness to others, plays a determining role
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2

Law, Cameron Hunter. "Investigation of chemical anchoring of nickel catalyst networks by aluminum titanate additives". Thesis, Montana State University, 2011. http://etd.lib.montana.edu/etd/2011/law/LawC0811.pdf.

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Electrocatalysts are incorporated into a plethora of technologies and material systems such as catalytic converters, reforming systems, multilayer ceramic capacitors, and solid oxide fuel cells (SOFCs). In SOFCs, nickel is commonly the catalyst of choice due to its chemical stability, high catalytic activity, and lower cost. While traditional SOFCs have a bulk mixture of nickel and yttria stabilized zirconia (YSZ) with at least 33 vol% nickel, solution infiltrated anode SOFCs have several benefits including lower nickel vol% to satisfy percolation, better mechanical strength and CTE matching that can improve redox cycling. Coarsening of the fine nickel metal catalyst with microstructures below 1 micrometer have shown a strong propensity to coarsen from thermal migration at temperatures above 700°C. This migration induced degradation by decreasing particle surface area and nickel network connectivity for electrical conduction. Utilizing metastable oxide additives as a minor dopant in the anode cermet system, novel methods of anchoring the metal phase to porous YSZ ceramic scaffolds have been identified as a means to engineer infiltrated anodes for improved performance. Less than 10 wt% aluminum titanate (ALT-Al ₂TiO ₅), added to YSZ by mechanical mixing, has shown a stepwise process in the formation of NiAl ₂O ₄ at 1100°C and ZrTiO ₄ at 1205°C for chemically binding the nickel phase to YSZ. XRD, SEM, TEM, and EDS characterization coupled with FIB sample preparation has been utilized to identify the size, morphology, composition and temperature at which the anchoring phases form. Area specific resistance tests of component anodes indicate a decrease in degradation of at least 521%/1000 hr compared to infiltrated specimens without the ALT additive. Electrochemical tests of electrolyte supported cells (ESC) show higher initial performance of cells doped with ALT and at least a 1400%/1000 hr reduction in performance degradation at the same nickel loading content. 'Co-authored by Stephen W. Sofie, Zane Townsend and Max Lifson.'
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3

Lantto, Cornelia. "Sulfur tolerance of SCR catalysts : Development of a lab testing method". Thesis, Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-64201.

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NOx emissions from diesel vehicles are a currently well-discussed matter due to the related health and environmental issues. At the same time, diesel vehicles are an important part of transportation in society as diesel engines are more fuel efficient than gasoline engines. NOx emissions are regulated by European standards, this put demands on a well-functioning exhaust gas aftertreatment system that lower the NOx emissions for the whole lifetime of the vehicle. One of the most effective solutions is by reduction of NOx with ammonia over a SCR catalyst. Cu/SSZ-13 zeolite has shown to be a promising SCR catalyst. SCR catalysts are however deactivated by several different mechanisms, where sulfur poisoning is a significant mechanism. There are many different factors that will influence how sulfur impacts the catalyst. Different catalyst materials are more or less sulfur tolerant. The form of sulfur is important as well as both temperature and availability of ammonia. It is thus important to investigate how sulfur affects the SCR catalyst.   The aim of this master’s thesis project was to develop a method for measuring sulfur tolerance of different SCR catalysts and to gain understanding of sulfur poisoning of Cu/SSZ-13 catalysts. A literature study on sulfur poisoning of SCR catalysts with a focus on Cu/SSZ-13 was first carried out. Followed by an experimental part in a rig at Scania CV AB in Södertälje, where the method was developed.   A method that can be used for testing SCR catalysts on sulfur tolerance after SO2 exposure was successfully achieved. The experimental procedure was designed to consist of eight steps, including de-greening, sulfur poisoning, regeneration at two temperatures and catalyst activity test after each step. Clear differences on NOx conversion between fresh, sulfated and regenerated catalysts are observed when using the method. Three different sulfation temperatures were evaluated where the lower sulfation temperatures, 220 ⁰C and 280 ⁰C, caused a larger impact on NOx conversion compared to sulfation at 350 ⁰C. Two different catalysts were compared on their NOx conversion over fresh, sulfated and regenerated catalysts. The method was correlated to engine aging with respect to sulfur exposure, sulfur capture, gas and temperature conditions and activity loss. The method corresponds to approximately 430 000 km driving based on sulfur exposure over the catalyst. The lab method is best comparable to a SCR catalyst located first in the exhaust gas aftertreatment system in a vehicle, based on two conclusions. (1) Poisoning is performed with only SO2. (2) Standard SCR conditions occur in the activity test.   The method should be further developed by enabling testing of NOx conversion at fast and slow SCR conditions. More work should be carried out on the correlation to vehicle aging by comparision with engine aged catalysts.
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4

Gotteland, Delphine. "Procédé d’hydroconversion par catalyse dispersée des résidus lourds pétroliers". Thesis, Lyon 1, 2011. http://www.theses.fr/2011LYO10198.

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5

Guilnaz, Mirmoshtaghi Seyedeh. "Simulation of a lab-scale methanation reactor". Thesis, KTH, Kemiteknik, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-90395.

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By the everyday increasing enthusiasm for using renewable-sustainable sources in energy production area, focusing on one and optimizing it in the best possible way should be of much interest. Biogas production from anaerobic digestion of wastes is a well known energy source which could be applied more efficiently if the CO2portion of it would be upgraded to CH4as well. There is a methanation reaction which could convert carbon dioxide to methane with the use of hydrogenation. In this report, the effort is to simulate this methanation reactor which is a catalytic bed of ruthenium on alumina base. The temperature change and its’ effect on reaction kinetics and equilibrium, also deriving designing parameters for the catalyst bed are different tasks which was tried to be covered in this thesis work. Based on calculations, the reactor can operate isothermally or adiabatically. The point is that each method has its own cons and pros. For the isothermal case finally the optimum temperature to run the reaction is decided to be 600 K in 10 bar total pressure. In adiabatic case then it is understood to work on interstage cooling strategy which in given conditions came to the number of 6 for reactors and 5 for interstage cooling devices. Afterwards it is thought to apply some technical changes to conventional adiabatic method and recycle some part of the product to the entrance of the reactor and assist the conversion. In this method number of reactors would be reduced to 2 and one heat exchanger in the middle. Selecting the best process in large scale treatment, needs lots of economical analysis and detail design while in small scale condition the most preferred method to run the reaction is isothermal.
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6

Boulens, Pierre. "Sulphonamido-phosphorus nickel complexes for the selective oligomerisation of olefins - Exploring dissymmetric ligands and supramolecular strategies". Thesis, Lyon, École normale supérieure, 2014. http://www.theses.fr/2014ENSL0973/document.

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Les alpha oléfines linéaires courtes sont des molécules de base en pétrochimie donc le marché est en constante augmentation notamment pour les oléfines légères (butène-1, hexène-1, octène-1). Ces oléfines, utilisées massivement dans l’industrie des plastiques, sont produites par la réaction catalytique d’oligomerisation de l’éthylène. IFPEN a contribué à développer plusieurs procédés homogènes d’oligomérisation de l’éthylène (AlphaButol, AlphaHexol, AlphaSelect) à base des complexes de titane, chrome ou zirconium. A travers une collaboration avec l’Université d’Amsterdam de nouvelles stratégies de développement de ligands ont été entreprises afin de rendre les catalyseurs à base de nickel sélectifs pour cette transformation. Ainsi, une approche supramoléculaire basée sur des interactions par liaison hydrogène, jusqu’alors décrite pour les métaux nobles, a été développée et appliquée aux complexes de nickel. Des complexes organométalliques originaux ont pu être générés et les interactions supramoléculaires ont été caractérisées par diffraction aux rayons X notamment. Ces complexes se présentent sous forme zwitterionique et sont formés par la combinaison de deux ligands simples donneurs et/ou accepteurs d’hydrogène. Ces complexes se sont avérés très actifs vis-à-vis de l’éthylène et ne nécessite pas l’ajout d’activateur du fait de la présence d’une liaison nickel-carbone réactive. Ils ont permis d’accéder à des sélectivités très importantes en butène-1. Appuyé par des expériences in situ et l’évaluation en catalyse de plusieurs complexes aux propriétés électroniques et stériques variées, cette approche a permis d’identifier l’espèce active et de mesurer l’impact de plusieurs descripteurs permettant de moduler la sélectivité et l’activité de la réaction catalytique en profondeur
The demand for short linear alpha olefins is constantly increasing and motivates the development of robust and selective catalysts. In this thesis, several libraries of phosphorus ligands with the capacity to form dissymmetric or supramolecular assemblies were synthesized. The variability observed within the aminophosphine libraries, clearly reflected by the various tautomeric equilibrium of the ligand, was also observed in the nickel complexes as a single ligand could generate several complexes with different structures. Sulphonyliminobisphosphine were then introduced as a new class of ligands. These precursors rearrange in the presence of nickel to generate diphosphinamine nickel complexes. Activated by MAO, these complexes are active in the reaction of ethylene oligomerisation and produce short chain olefins. A new approach that forms stable supramolecular nickel complexes was developed by combining two phosphorus ligands with Ni(0). These complexes stabilised by hydrogen bonding are directly active in the reaction of ethylene oligomerisation with some catalysts leading to high selectivity to 1-butene (up to 84%). To understand the origin of that selectivity, the scope of complexes was extended to ligands with different steric and electronic properties. Their evaluation in the reaction of ethylene oligomerisation evidenced a relation between the catalyst structure and the selectivity of the reaction. Mechanistic studies, under an ethylene atmosphere, reveals that cationic complexes rearrange to neutral complexes, which are likely, the active species
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7

Marchand, Paul R. "The export development corporation : catalyst in Canada's promotion of international trade". Thesis, McGill University, 1985. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=64491.

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8

Payne, Bridget Áine. "State-Financed Merger and Acquisition Activity in Germany as a Catalyst for Robust Chinese Patent Law Enforcement". Scholarship @ Claremont, 2018. http://scholarship.claremont.edu/scripps_theses/1171.

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Germany’s economic dominance in Europe, generous investment incentives, and technical manufacturing prowess has encouraged an influx of Chinese-led inbound activity, concentrated in high-tech sector mergers and acquisitions. A close examination of these M&As yields evidence of systemic Chinese state-financing through both state-owned and private vehicles that likely stems from China’s “Made in China 2025” policy, which hopes to stem capital outflow and to indigenize technological innovation. As Germany braces for what it sees to be continuous attempts by China to take patented German technology through M&As, it worries that Chinese patent law will allow for rampant patent infringement by copycat Chinese entities. This paper presents an overview of the root causes of China’s heavy economic activity in Germany, as well as an analysis of the legal concerns held by German firms based on a close reading of the Patent Law of the People’s Republic of China and strategic recommendations for German companies hoping to work with or in China.
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9

Vlachos, Chris Alex. "Law and sin an Edenic nexus? : a study with reference to 1 Corinthians 15:56 and the catalytic operation of the law /". Theological Research Exchange Network (TREN), 2006. http://www.tren.com/search.cfm?p088-0157.

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10

Martin, Derrick W. A. "From the Desire to Mark Essex: The Catalysts of Militarization for the New Orleans Police Department". ScholarWorks@UNO, 2016. http://scholarworks.uno.edu/td/2174.

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Abstract The ultimate goal in the South was to end segregation, but nationwide equal-rights were the common goal of all African-Americans. Nonviolent protests and over aggressive police departments became the norm within the African-American community. Understated in the history of the Civil Rights Era is the role of armed resistance and Black Nationalism. Marcus Garvey, Stokely Carmichael, Huey P. Newton, and Malcolm X were Black Nationalists that led the charge of Black Nationalism worldwide. The Deacons of Defense, the Lowndes County Freedom Organization (LCFO) and the Black Panther Party for Self Defense transformed the social makeup of the country and became major causes of the militarization of police departments across the United States. Many police departments across America began to create SWAT teams and use military-style weaponry following an outbreak of riots and the assassination of Dr. Martin Luther King Jr. In New Orleans, Louisiana, stand-offs and shoot-outs with Black Panther members warranted a call for military backup, but it was the acts of Mark James Robert Essex that totally militarized the New Orleans Police Department.
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11

Du, Toit Elizabeth Louisa. "The Rate inhibiting effect of water as a product on reactions catalysed by cation exchange resins formation of mesityl oxide from acetone as a case study /". Diss., Pretoria : [s.n.], 2003. http://upetd.up.ac.za/thesis/available/etd-02272004-140347.

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12

Fichera, Alfio. "Syntheses of triflu[o]romethyl-containing amino acids and development of catalysts capable of hydrolyzing the D-Ala-D-Lac depsipeptide /". Thesis, Connect to Dissertations & Theses @ Tufts University, 2004.

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Thesis (Ph.D.)--Tufts University, 2004.
Adviser: Krishna Kumar. Submitted to the Dept. of Chemistry. Includes bibliographical references (leaves 190-197). Access restricted to members of the Tufts University community. Also available via the World Wide Web;
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13

Nouwen, Sarah Maria Heiltjen. "Complementarity in conflict : law, politics and the catalysing effect of the International Criminal Court in Uganda and Sudan". Thesis, University of Cambridge, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.609009.

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14

Schweizer, Stéphane. "Développement de catalyseurs réutilisables au palladium supporté sur polymère : applications à la formation de liaisons carbone-carbone". Mulhouse, 2008. https://www.learning-center.uha.fr/opac/resource/developpement-de-catalyseurs-reutilisables-au-palladium-supporte-sur-polymere-applications-a-la-form/BUS4085749.

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Les réactions pallado-catalysées de formation de liaisons carbone-carbone ont actuellement une importance cruciale. Les catalyseurs homogènes habituels présentent deux inconvénients majeurs : d'une part ils sont très onéreux et ne peuvent pas être réutilisés, même si le métal précieux lui-même peut être récupéré ; d'autre part il subsiste des traces de palladium dans rejets et produits, ce qui provoque des étapes de purification des produits coûteuses. Nous avons donc préparé des catalyseurs hétérogènes réutilisables où le palladium est supporté sur un polymère, dérivé du polymère de Merrifield, portant divers groupements phosphino. Des catalyseurs comportant des ligands diarylphosphino sont très efficaces pour les couplages de Suzuki à partir de bromures d'aryles, ainsi que pour les réactions de Heck et de Sonogashira à partir d'iodures d'aryles, en présence de 0,5 à 2,5 milliéquivalents de palladium supporté. Pour réaliser le couplage de Suzuki avec des chlorures d'aryles, substrats d'ordinaire peu réactifs, mais peu chers et faciles d'accès, nous avons préparé des catalyseurs comportant des ligands alkylarylphosphino. Ces catalyseurs sont moins résistants en présence de solvants protiques (ce qui a nécessité des conditions expérimentales particulières pour le couplage) mais aussi beaucoup plus actifs et d'excellents rendements ont pu être obtenus avec de nombreux chlorures d'aryles. Comme il s'agit du premier catalyseur supporté d'utilisation générale pour ce couplage, un brevet a été déposé. Tous ces catalyseurs peuvent être réutilisés de nombreuses fois sans perte d'activité et les pertes en palladium sont minimes (quelques microéquivalents par rapport au substrat)
Palladium-catalyzed reactions have now a crucial importance for the formation of carbon-carbon bonds. The usual homogeneous catalysts present two major disadvantages : firstly they are very expensive and usually cannot be recovered for reuse, only the precious metal itself can be recovered, secondly traces of palladium remain in waste and products, which requires expensive purification steps of the products. We have therefore prepared reusâble heterogeneous catalysts, where the palladium is supported on a polymer bearing various phosphino groups, prepared from a Merrifield polymer. Catalysts possessing diarylphosphino ligands are very efficient for the Suzuki coupling reactions from aryl brodes, and for the Heck and Sonogashira reactions from aryl iodides, in the presence of 0. 5 to 2. 5 milliequivalents of supported palladium. To perform the Suzuki coupling from aryl chlorides, which possess only a weak reactivity, but are cheap and easily accessible, we have prepared catalysts bearing alkylarylphosphino ligands. These catalysts are more sensitive in the presence of protic solvents, (specific experimental conditions for the coupling reaction had to be devised) but also much more reactive. Excellent yields were obtained for the coupling reactions from many aryl chlorides. We patented this supported catalyst, which is the first catalyst of general use for this coupling reaction from aryl chlorides. All our supported catalysts could be reused many times without showing any loss of efficiency and palladium losses are minimal (some microequivalents of the substrate)
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15

Kelly, Elizabeth. "The spaceplane, the catalyst for resolution of the boundary and space object issues in the law of outer space?" Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape10/PQDD_0022/MQ50938.pdf.

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Kelly, Elizabeth 1962. "The spaceplane : the catalyst for resolution of the boundary and "Space Object" issues in the law of outer space?" Thesis, McGill University, 1998. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=21687.

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The spaceplane could be the most desirable form of space transportation in the next century. However, accompanying it are questions of whether a boundary is needed between airspace and outer space, and whether the current definition of 'space object' in the outer space treaties is adequate to include these hybrid vehicles This thesis concludes that the spaceplane does not portend the need for a boundary and that it will not require the development of a new definition. Chapter I describes some of the best known spaceplane initiatives. Chapters II and III, respectively, discuss the air law and space law regimes and arguments made for and against establishing a boundary between airspace and outer space. Chapter IV describes debates regarding the sufficiency of the term 'space object' as it is defined in the space law regime. Chapter V analyzes the impact that spaceplanes will have on the boundary and 'space object' debates.
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17

Komissarenko, Dimitry. "Selective catalytic oxidation of methane to synthesis gas over complex oxides of cobalt and rare earth elements". Thesis, Strasbourg, 2015. http://www.theses.fr/2015STRAF063/document.

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Pour la première fois l'oxydation partielle du méthane en gaz de synthèse a été effectué en présence de pérovskites lamellaires Nd2-xCaxCoO4±δ et La2-xSrxCoO4±δ (x = 0.75; 1.0). Nouveau catalyseur d'oxydation partielle NdCaCoO3.96 de méthane a été suggéré qui permet d’obtenir la sélectivité en gaz de synthèse proche de 100% avec 90% de la conversion de CH4 (T = 900ºC; CH4/O2 = 2; W = 20 L·g-1·h-1; brevet russe № 2433950, 21/04/2010). Le catalyseur a été active et stable au moins 140 h, aucune tendance à la désactivation n’a été observée. Sur la base des analyses DRX, MEB et MET, il a été déterminé que l'activité et la sélectivité élevées de NdCaCoO3.96 ainsi que la stabilité dans l'oxydation partielle du méthane sont dues à sa transformation au cours de la réaction de la structure initiale en des nanoparticules de cobalt métallique dispersées dans Nd2O3-CaO matrice. Il a été observé que l'activité des pérovskites lamellaires dans l'oxydation partielle du méthane dépend à la fois de la taille des particules métalliques actives formées et à la stabilité de la structure initiale
For the first time partial oxidation of methane to synthesis gas over layered perovskite-type oxides Nd2-xCaxCoO4±δ and La2-xSrxCoO4±δ (x = 0.75; 1.0) was investigated. New catalyst NdCaCoO3.96 for partial oxidation of methane was suggested allowing the selectivity toward synthesis gas close to 100% with 90% of CH4 conversion (T = 900ºC; CH4/O2 = 2; W = 20 L·g-1·h-1; Russian patent № 2433950, 21/04/2010). The catalyst was active and stable at least for 140 h, no trend to deactivation was observed. Based on XRD, SEM and TEM results it was determined that high activity and selectivity of NdCaCoO3.96 as well as stability in partial oxidation of methane are due to its transformation during reaction of initial structure to nanosized particles of metallic cobalt dispersed in Nd2O3-CaO matrix. It was observed that the activity of synthesized layered perovskite-type oxides in partial oxidation of methane depends both on the size of the formed active metallic particles and on the stability of initial structure
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18

Vick, Alison Marie. "A Catalyst for the Development of Human Rights: German Internment Practices in the First World War,1914-1929". Thesis, Virginia Tech, 2013. http://hdl.handle.net/10919/23242.

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This thesis is a transnational study of the military actions and responses related to prisoners of war in World War I. Building on the works human rights scholars, I explore the how the collective rights afforded to prisoners of war under the 1906 Geneva Convention and 1907 Hague Convention served as a precursor to the concept of human rights that emerged after World War II. I argue that German military treated prisoners of war according to national interest, rather than international law. Specifically, I explore how the concepts of "military necessity" and "reciprocity" drove German internment practices, and how German internment practices escalated in violence during the last two years of the war. The violent practices committed by the Germans against prisoners of war produced an international demand to hold the perpetrators of wartime atrocities accountable for their actions in the postwar period.
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19

Dal, Zotto Christophe. "Utilisation des propriétés acide de Lewis et π-acide des sels de fer (III) en catalyse". Montpellier 2, 2009. http://www.theses.fr/2009MON20155.

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Utilisation des propriétés pi-acide et acide de Lewis des sels de fer (III) en catalyse La partie principale de ce manuscrit traite des réactions catalysées par des sels de fer. Des additions de dicétones sur des styrènes et alcènes conjugués, des réactions d'hydroarylation intramoléculaire d'alcynes et d'alcènes, et la réduction complète de dérivés carbonylés (aldéhydes et cétones) ont pu être catalysées par du chlorure de fer (III). Une partie annexe décrit, quant à elle, une approche vers la fonctionnalisation d'histidines. Des histidines N-arylées ont alors été obtenues par une réaction de couplage au cuivre (II) de Chan-Lam-Evans
Iron (III) catalyzed reactions on homo- and hetero- polyinsaturated bounds The main part of this manuscript deals with iron salts catalyzed reactions. Alkenes functionalization using diketones, intramolecular hydroarylation of alkynes and alkenes, reduction of carbonyl compounds have been catalyzed using iron (III) chloride. The annex describes an approach towards the functionalization of histidines. N-aryl substituted histidines have been obtained, in good yields, by Copper (II) catalyzed Chan-Lam-Evans coupling
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20

Moraes, Júnior Eugênio Oliveira. "Desenvolvimento de catalisadores com estrutura perovsquita do tipo La1-xSrxNiO3 pelo método do gel proteico modificado com soja e colágeno". Pós-Graduação em Química, 2013. https://ri.ufs.br/handle/riufs/6089.

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In this work, the perovskite oxides La1-xSrxNiO3 (x = 0,0, 0,3 e 0,7) partially replacing lanthanum by strontium were prepared by the method of protein gel, modified using collagen and soy as chelating agents. All samples were synthesized and calcined at 900°C for 2 hours and characterized by thermogravimetric techniques (TG), spectroscopy of absorption in the infrared region (FTIR), X-ray diffraction (DRX), specific surface area and temperature programmed reduction. The calcined samples were supported on alumina. The FTIR spectra showed bands related to the complexation of the metals to the oxygen. The thermogravimetric curves indicated thermal stability of materials at 900°C, except, the La0,3Sr0,7NiO3 samples that showed a decomposition about 800°C. The X-ray diffraction results indicated the formation of the perovskite phase in all samples, but there was the formation of secondary phases in all samples replaced. The samples that presented less formation of secondary phases were obtained using the collagen as a chelating agent. The supported material presented peaks related to the perovskite phase. The specific surface areas of the catalysts increased when supported on alumina. The complete reduction of the supported samples, obtained by the method of protein gel using the collagen occurred at temperatures below 700°C. The obtained samples using collagen as a chelating agent and supported with 15% of perovskite were tested by the reaction of partial oxidation of methane, when also were analysed methane conversion level and selectivity to CO, CO2, H2 and H2O. Among the catalysts studied, the catalyst LN9-C15 showed the highest level of methane conversion, 78%, and the better selectivity to H2, 55%.
Neste trabalho, os óxidos tipo perovsquita La1-xSrxNiO3 (x = 0,0, 0,3 e 0,7), substituindo parcialmente o lantânio por estrôncio, foram preparados através do método do gel proteico, modificado usando colágeno e soja como agentes quelantes. Todos os materiais foram sintetizados e calcinados a 900ºC por 2 horas e caracterizados pelas técnicas de termogravimetria (TG), espectroscopia de absorção na região do infravermelho (FTIR), difratometria de raios X (DRX), área superficial específica e redução a temperatura programada. As amostras calcinadas foram suportadas em alumina. Os espectros FTIR mostraram bandas relacionadas à complexação dos metais ao oxigênio. As curvas termogravimétricas indicaram estabilidade térmica dos materiais a 900ºC, com exceção das amostras L3S7N9 que mostraram uma decomposição próxima a 800ºC. Os resultados de difração de raios X indicaram a formação da fase perovsquita em todas as amostras, porém houve a formação de fases secundárias para as amostras substituídas. As amostras que apresentaram menor formação de fases secundárias foram obtidas usando o colágeno como agente quelante. Os materiais suportados apresentaram picos relacionados à fase perovsquita. As áreas superficiais específicas dos catalisadores aumentaram quando suportadas em alumina. A redução completa das amostras suportadas, obtidas pelo método do gel proteico utilizando o colágeno aconteceram a temperatura abaixo de 700ºC. As amostras obtidas usando o colágeno como agente quelante e suportadas com 15% de perovsquita foram testadas frente a reação de oxidação parcial do metano, no momento foram avaliados os respectivos níveis de conversão do metano e seletividade ao CO, CO2, H2 e H2O. Dentre os catalisadores estudados, o catalisador LN9-C15 foi o que apresentou maior nível de conversão de metano, 78%, e maior seletividade ao H2, 55%
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21

Mahai-Batel, Asma. "La diplomatie humanitaire et le droit international humanitaire : de l'empirisme à une diplomatie de catalyse ?" Thesis, Université Côte d'Azur (ComUE), 2019. http://theses.univ-cotedazur.fr/2019AZUR0036.

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La notion de diplomatie humanitaire, objet d’études théoriques encore peu nombreuses, comporte des périmètres fluctuants, selon qu’on la limite à des négociations accompagnant l’action humanitaire ou que l’on y intègre la diplomatie relative au droit international humanitaire et ses différentes fonctions portées par de multiples acteurs. L’étude des rapports entre la diplomatie humanitaire et le droit international humanitaire (DIH) révèle sa grande plasticité à travers le temps, tant dans le domaine de l’évolution de ses objets -d’abord concentrée sur le développement des sources du DIH, puis sur l’amélioration de la mise en œuvre de ce droit- que de ses acteurs -initiée par des acteurs privés, tel Henry Dunant et les premières sociétés de secours, menée par les Etats, avant d’être à nouveau déterminée largement par une société civile organisée dans le cadre de puissantes ONG-.Ces fluctuations, mises en évidence dès l’Antiquité, concernent la diplomatie relative aux sources matérielles et formelles du DIH, qui a, dans une première approche empirique, révélé et affirmé les valeurs du DIH. La structuration progressive d’un réseau de parties prenantes des négociations conventionnelles a ensuite permis l’affirmation de méthodes propres à ce champ de la diplomatie, qui s’est écarté très tôt de celui de la diplomatie classique. Confrontée aux défis contemporains du DIH et à la transformation de la conflictualité, la diplomatie humanitaire est désormais caractérisée par l’apparition de nouvelles formes de négociations, émancipées des techniques basées sur la confidentialité, où les prérogatives de l’Etat reculent face à la montée en puissance des ONG. La prolifération des acteurs, mais également la flexibilité des méthodes et objets de négociations révèlent l’enrichissement d’une diplomatie créatrice du DIH par une diplomatie opérationnelle, constitutive d’une « diplomatie de catalyse », susceptible de permettre des adaptations des normes de ce corpus
The concept of humanitarian diplomacy, which is still the subject of few theoretical studies, has fluctuating boundaries, depending on whether it is limited to negotiations accompanying humanitarian action or whether it includes diplomacy relating to international humanitarian law and its various functions carried out by multiple actors. The study of the relationship between humanitarian diplomacy and international humanitarian law (IHL) reveals its great plasticity over time, both in the field of the evolution of its objects - first focused on the development of IHL sources, then on improving the implementation of this law - and in its actors - initiated by private actors, such as Henry Dunant and the first relief societies, led by States, before being largely determined once again by a civil society organized through powerful NGOs -.These fluctuations, highlighted since antiquity, concern diplomacy relating to the material and formal sources of IHL, which has, in a first empirical approach, revealed and affirmed the values of IHL. The gradual structuring of a network of stakeholders in conventional negotiations then made it possible to affirm methods specific to this field of diplomacy, which very early on deviated from that of conventional diplomacy. Faced with the contemporary challenges of IHL and the transformation of conflict, humanitarian diplomacy is now characterized by the emergence of new forms of negotiation, emancipated from techniques based on confidentiality, where the prerogatives of the State recede in the face of the rise in power of NGOs. The proliferation of actors, but also the flexibility of methods and subjects of negotiation reveal the enrichment of a creative diplomacy of IHL by an operational diplomacy, constituting a "catalyst diplomacy", likely to allow adaptations of the norms of this corpus
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22

Elmously, Mohamed [Verfasser], Andreas [Akademischer Betreuer] Hornung y Michael [Gutachter] Wensing. "Experimental Study of Thermo-Catalytic Reforming of Biogenic Waste Streams and their Simulation from Lab to Pilot Scale / Mohamed Elmously ; Gutachter: Michael Wensing ; Betreuer: Andreas Hornung". Erlangen : Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 2021. http://d-nb.info/123675512X/34.

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23

Villca, Pozo Ariel Rey. "Utilización de geopolímero para la mejora de las propiedades en morteros cal-puzolana y su empleo en países en desarrollo". Doctoral thesis, Universitat Politècnica de València, 2021. http://hdl.handle.net/10251/172663.

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[ES] El descubrimiento del cemento Portland ha cambiado nuestra forma de construir, pero también es el responsable de grandes emisiones de CO2 a la atmósfera durante su fabricación (~1450 ᴼC), agravando la crisis actual que está sufriendo nuestro planeta debido al cambio climático y sus consecuencias en todo el medio ambiente. Por lo tanto, una alternativa más sostenible en la construcción es la utilización de la cal que necesita menor temperatura para su fabricación (~900 ᴼC). Si bien la introducción de puzolanas naturales o artificiales en morteros de cal han mejorado sus propiedades mecánicas y de durabilidad, estas aún tienen el inconveniente de ganar resistencias a edades largas de curado. Es por esta razón que en la presente tesis se pretende eliminar este inconveniente técnico, buscando la asociación de la cal con nuevos conglomerantes más sostenibles a partir de residuos para obtener morteros mixtos denominados cal/puzolana-geopolímero. Los residuos estudiados fueron: el catalizador gastado de craqueo catalítico, la ceniza de cascara de arroz, la tierra diatomea de origen residual y la ceniza de lodo de depuradora. También se estudia una puzolana natural proveniente de la República de Guatemala. En los morteros cal/puzolana (cal/FCC, cal/CCA, cal/CLD) se ha realizado sustituciones en peso hasta un 50 % de la mezcla cal/puzolana por geopolímero. El geopolímero se obtiene por una combinación del FCC como precursor y diferentes activadores alcalinos siendo estos la mezcla de: NaOH/Na2SiO3, NaOH/CCA, NaOH/TDN y NaOH/TDR. Los últimos tres sustituyen al silicato comercial como fuente de sílice alternativa. Asimismo, se realizaron estudios a nivel mecánico y microestructural. Para los estudios microestructurales, tanto de muestras endurecidas como de materiales de partida, se emplearon como técnicas: FRX, ADL, TG, DRX y FESEM. Los resultados han demostrado con éxito que añadir pequeñas cantidades de geopolímero sobre el sistema cal/puzolana fue notable, debido a que este potenció la formación de los nuevos productos de reacción, lo que mejoró la resistencia mecánica de los morteros desde las primeras horas de curado, llegando a obtener 7 veces más de resistencia que un mortero control cal/puzolana en 1 día de curado. El reemplazo del silicato de sodio comercial por CCA, TDN, TDR, como fuente de sílice, condujo a mejores desempeños del mortero en términos de resistencia a la compresión. Además, redujo el coeficiente de absorción de agua por capilaridad y aumento el tiempo de exposición a los ciclos hielo-deshielo frente a los morteros activados con activadores comerciales. Finalmente, los conglomerantes desarrollados en este estudio podría beneficiar tanto a la gestión de residuos como al desarrollo de materiales de construcción más sostenibles, aportando a los objetivos propuestos en la agenda 2030.
[CA] El descobriment del ciment Portland ha canviat la nostra manera de construir, però també és el responsable de grans emissions de CO¿ a l'atmosfera durant la seva fabricació (~1450 ᴼC), agreujant la crisi actual que està patint el nostre planeta degut al canvi climàtic i les seves conseqüències en tot el medi ambient. Per tant, una alternativa més sostenible en la construcció és la utilització de la calç que necessita menor temperatura per a la seva fabricació (~900 ᴼC). Si bé la introducció de putzolanes naturals o artificials en morters de calç han millorat les seves propietats mecàniques i de durabilitat, aquestes encara tenen l'inconvenient de guanyar resistències a edats llargues de curat. És per aquesta raó que en la present tesi es pretén eliminar aquest inconvenient tècnic, buscant l'associació de la calç amb nous conglomerants més sostenibles a partir de residus per a obtenir morters mixtos denominats calç/putzolana-geopolímer. Els residus estudiats van ser: el catalitzador gastat del craqueig catalític, la cendra de closca d'arròs, la terra diatomea d'origen residual i la cendra de llot de depuradora. També es va estudiar una putzolana natural provinent de la República de Guatemala. En els morters calç/putzolana (calç/FCC, calç/CCA, calç/CLD) s'ha realitzat substitucions en pes fins a un 50 % de la barreja calç/putzolana per geopolímer. El geopolímer s'obté per una combinació del FCC com a precursor i diferents activadors alcalins, sent aquests la mescla de: NaOH/Na2SiO3, NaOH/CCA, NaOH/TDN i NaOH/TDR. Els últims tres substitueixen al silicat comercial com a font de sílice alternativa. Així mateix, es van realitzar estudis a nivell mecànic i microestructural. Per als estudis microestructurals, tant de mostres endurides com de materia primera, es van emprar tècniques com: FRX, ADL, TG, DRX i FESEM. Els resultats han demostrat amb èxit que afegir petites quantitats de geopolímer sobre el sistema calç/putzolana va ser notable, pel fet que aquest va potenciar la formació dels nous productes de reacció, la qual cosa va millorar la resistència mecànica dels morters des de les primeres hores de curat, arribant a obtenir 7 vegades més de resistència que un morter control calç/putzolana en 1 dia de curat. El reemplaçament del silicat de sodi comercial per CCA, TDN, TDR, com a font de sílice, va conduir a millors acompliments del morter en termes de resistència a la compressió. A més, va reduir el coeficient d'absorció d'aigua per capil·laritat i va augmentar el temps d'exposició als cicles gel-desgel enfront dels morters activats amb activadors comercials. Finalment, els conglomerants desenvolupats en aquest estudi podrien beneficiar tant a la gestió de residus com al desenvolupament de materials de construcció més sostenibles, aportant als objectius proposats en l'Agenda 2030.
[EN] The discovery of Portland cement has changed the way we build; however, it is also responsible for large CO2 emissions into the atmosphere during its manufacturing (~ 1450 ᴼC), thereby aggravating the current crisis that our planet is suffering due to climate change and its consequences in the environment. Thus, a more sustainable alternative in construction is the use of lime that requires a lower temperature for its manufacturing (~ 900 ᴼC). The introduction of natural or artificial pozzolans in lime mortars has improved their mechanical properties and durability. Nevertheless, they present some technical disadvantages, as the low compressive strength, especially at early curing time. This thesis aims to eliminate this technical disadvantage by mixing lime with new more sustainable binders derived from waste, obtaining mixed mortars called lime/pozzolan-geopolymer The waste materials studied included fluid catalytic cracking residue (FCC), rice husk ash (CCA), residual diatomite (TDR) and sewage sludge ash (CLD). A natural pozzolan from the Republic of Guatemala was also studied. In the experimental procedure, in lime/pozzolan mortar mixtures (lime/FCC, lime/CCA, lime/CLD), up to 50% of their weight was substituted by geopolymer. The geopolymer is obtained by combining FCC as a precursor, and different alkaline activator mixtures including NaOH/Na2SiO3 (commercial waterglass), NaOH/CCA, NaOH/TDN, and NaOH/TDR, with the last three being an alternative silica source to commercial waterglass. In the same way, both mechanical and microstructural studies were carried out. The following techniques were used: XRF, ADL, TG, XRD and FESEM to assess the microstructural properties of both the raw materials and the hardened samples. The results have demonstrated that adding small amounts of geopolymer to the lime/pozzolan system was remarkable; it enhanced the formation of new reaction products, which improved the mechanical strength of the mortar from the first hours of curing, obtaining 7 times more strength than the lime/pozzolan control mortar in 1 day of curing. The replacement of commercial waterglass by CCA, TDN, TDR, as a source of silica, led to better performance of the mortar in terms of compressive strength. In addition, the coefficient of water absorption by capillarity was reduced and the exposure time during freezing-thawing cycles was increased compared to mortars activated with commercial activators. Finally, the binders developed in this study could benefit both waste management and the development of more sustainable construction materials, contributing to the objectives proposed in the 2030 Agenda.
Gracias al programa ADSIDEO-COOPERACIÓN de la Universitat Politècnica de València, que me ha brindado financiación para la presente investigación.
Villca Pozo, AR. (2021). Utilización de geopolímero para la mejora de las propiedades en morteros cal-puzolana y su empleo en países en desarrollo [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/172663
TESIS
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24

Jebri, Khouloud. "Couplage en liquide ionique pour l'accès à des molécules macrocycliques d'intérêt biologique". Thesis, Toulouse 3, 2016. http://www.theses.fr/2016TOU30351.

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Le présent travail décrit l'utilisation des liquides ioniques comme solvant de réaction dans plusieurs types de couplage permettant la création de liaisons C-C, C-N et C-O. Dans un premier temps, ces solvants ont permis d'effectuer la synthèse des a-oxo gamma-thio-esters via la réaction de condensation de Mukaiyama de l'énoxysilane du pyruvate d'éthyle sur des thioacétals. Dans le cadre d'une stratégie de synthèse multi-étape en liquide ionique, la synthèse des produits de départ a été également menée à bien dans ces solvants. Ensuite, une application des liquides ioniques dans la chimie des peptides a été décrite. Une série de di- et tri-peptides formés essentiellement par des dérivés de la tyrosine a été obtenue avec de bons rendements dans ces milieux ioniques, en ayant recours à des agents de couplage modernes tels que HATU et BOP. Une réactivité différente a été observée dans les liquides ioniques comparée à celle dans les solvants moléculaires classiques. Des sels de cuivre (I) et (II) ont été utilisés pour catalyser la réaction de couplage diaryl éther intermoléculaire dans les liquides ioniques, à partir des dérivés de la tyrosine afin d'obtenir des motifs isodityrosines. Le couplage d'Ullmann n'a pas été efficace à cause de la présence de contraintes électroniques et stériques, tandis que le couplage de Chan-Lam s'est révélé plus intéressant et il a permis d'obtenir les motifs isodityrosines avec des rendements satisfaisants. De plus, celui-ci présente l'avantage d'utiliser des conditions opératoires plus douces
This thesis describes our studies regarding the organic synthesis in ionic liquids allowing the creation of C-C, C-N and C-O bonds. We describe the synthetic approaches of alpha-oxo gamma-thio-esters via the Mukayaima condensation of the enoxysilane of ethyl pyruvate on thioacetals. In the context of a multi-step synthesis strategy in ionic liquid, the synthesis of the starting materials was also carried out in these solvents. We also present an application of ionic liquids in peptide chemistry: cyclopeptides containing biaryl and biaryl ether linkages. These compounds have attracted considerable interest due to the significant biological activities that most of them exhibit, including antimicrobial and cytotoxic activities. We describe the synthetic approaches of macrocyclic peptides from tyrosine derivatives in ionic liquids. Two main strategies are investigated for the synthesis of macromolecules, peptidic coupling from tyrosine derivatives followed by formation of the biaryl ether bridge as key step and macrolactamization of the preformed biaryl ether, using modern coupling agents such as HATU and BOP. A different reactivity was observed in ionic liquids compared to that in conventional molecular solvents. Copper (I) and (II) salts have been used to catalyze the intermolecular diaryl ether coupling reaction in ionic liquids from tyrosine derivatives to obtain isodityrosine units. Ullmann coupling was not effective due to the presence of electronic and steric constraints, while the Chan-Lam coupling proved to be more advantageous and allowed the formation the isodityrosine units with satisfactory yields . In addition, the Chan-Lam has the advantage of using milder operating conditions
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25

SANTARSIERO, FRANCESCO. "Innovation Labs for Digital Transformation Strategies and Business Model Innovation in the Digital Age: a Focus on Tourism and Cultural Sector". Doctoral thesis, Università degli studi della Basilicata, 2021. http://hdl.handle.net/11563/148962.

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The research proposes the Innovation Labs as a valuable management initiative to support tourism and cultural organisations in developing Digital Innovation Capacity, fostering Digital Transformation (DT) and Business Model Innovation (BMI). Innovation Labs are innovation management models aimed at fostering creative and critical thinking, driving the organisation in finding the best ways to generate knowledge and digital culture, introduce technologies, digitise operations, and implement digital strategies for continuous and sustainable innovation paths (Santarsiero et al., 2019; 2020). The need for investigating and identifying possible solutions, and governance models, in terms of management initiatives that follow emergent innovation trends, and support tourism and cultural organisations in embracing digital innovation journeys, is having a growing interest, both in scholars and practitioners, especially after the pandemic Covid-19. Tourism and cultural organisations, pursuant their attitude to be a labour-intensive production sector, in which the competitive advantage depends on the differentiation of the tourism product and the humanisation of the offered experiences, resulted as one of the sectors that most repudiate DT, conceiving it as a process that would lead to standardisation and loss of appeal to the end customer. However, nowadays, due to the emerging challenges in the Digital Age that are also affecting the tourism and cultural sector, the need for embracing digital journeys favouring DT and BMI should be considered mandatory to guarantee competitiveness and the gain of a sustainable competitive advantage. The rapid development of digital technologies and solutions, and their democratisation, induced changes in consumers’ and users’ habits and behaviours, resulting in the need for developing new products, services and methods of use based on emerging market needs. In the same way, organisations are asked to become resilient, proactive and able to evolve in the same way the competitive landscape does. After Covid-19, besides, the needs for digital innovation journeys and digital revolutions are even more accentuated, confirming that the pandemic has acted as an accelerator of DT dynamics. The competitiveness and attractiveness of organisations and destinations will therefore depend on the digital innovative capacity and ability of operators and destination managers to rethink the tourist offer according to the new emerging trends and context dynamics. Although the need for embracing digital innovation journeys is crucial, it is not an easy process to manage and exploit. Organisations, indeed, experience several difficulties and innovation barriers. In SMEs, in particular, which represent a typical configuration of tourism and cultural organisations, resistance to innovation, and insufficient skills, finance, culture, attitudes, and often also the time to devote to innovation due to overburden of bureaucratic aspects and various routines, are particularly accentuated. It follows these organisations require forms of support to face these needs and develop an innovative capacity, fostering DT and BMI to improve offers, competitiveness, efficiency, as well as customisation and customer relationships. Despite the relevance of these topics, however, the search for solutions and ways to support tourism and cultural organisations in embracing digital innovation journeys has not structurally explored yet. On this vein, the research aims to explore and investigate, in the field of innovation management, models and approaches to face DT and BMI challenges and opportunities, and thus to investigate the emerging phenomenon of Innovation Labs to understand their management model and assess their suitability for tourism and cultural organisations. In the theoretical section, the study presents a systematic literature review of Innovation Labs to provide a comprehensive understanding of the phenomenon and identify critical patterns according to two main dimensions of analysis: space & infrastructure, and strategy & management. Furthermore, the study utilises a multiple-case study approach to better enrich the insights gathered from the literature, and to propose an Innovation Lab’s working definition and a management framework. The working definition takes into account all the emerging aspects, the new principles and paradigms that are governing the field of innovation management and that become essential for the organisations competing in this scenario. The framework describes key phases and relevant issues for effective management of Innovation Labs as catalysts of DT and BMI. Then, the research applies the proposed framework through an Action Research (AR) project involving an organisation operating in the tourism sector, to assess its efficacy in fostering tourism and cultural organisations’ digital innovation journeys. The research contributes to enrich knowledge and build theory in the field of Innovation Labs and tourism innovation management. In particular, the study led to developing theories on the contributions of Innovation Labs in fostering DT and BMI in tourism organisations. A further framework explaining the business model’s dimensions on which DT processes impact thanks to these initiatives has been proposed. Lastly, the analysis of the AR project compared Innovation Labs’ management framework with change management frameworks to detect alignments and to highlight insights to support researchers in considering the model as a tool to support innovation dynamics in times of crisis. This research also has relevant practical implications since it provides managers and practitioners with an overview of the dimensions to be considered while designing and managing an Innovation Lab to develop digital innovation capacity and foster DT and BMI. Expressly, managers and practitioners are provided with a framework supporting them designing and exploiting management initiatives aimed at embracing digital innovation journeys to generate marketable digital solutions, improve performance and develop a mindset continuous learning and innovation. The study also reveals some limitations that may address future research. Further empirical, also quantitative, investigations could be developed to extend the sample and to allow a comprehensive validation of the Innovation Lab’s management framework, focusing the research also on the evaluation of Innovation Labs’ activities.
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26

Shaikh, Yacoob. "Towards Selective Ethylene Tetramerization". Thèse, Université d'Ottawa / University of Ottawa, 2012. http://hdl.handle.net/10393/23161.

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There is an increasing trend towards advancing the understanding and development of ethylene oligomerization catalysts, both in academia and industry. The metal of choice in this chemistry is invariably chromium, which has shown great versatility in selective trimerization/tetramerization, non-selective oligomerization and polymerization of ethylene. While much success has been achieved in ethylene trimerization, the same con not be said about tetramerization catalysis. Aminophosphine based ligands have demonstrated their ability towards selective 1-octene production, however, the popular PNP catalyst is able to achieve only 70% selectivity. In order to explore the possibility of developing and enhancing the selectivity of chromium based ethylene tetramerization catalyst, this thesis work was undertaken. The ligand systems we chose for our work were bidentate aminophosphine based (PN(CH2)nNP), which has yielded interesting selective oligomerization. Subtle modifications were found to result in drastic changes in selectivity, from tetramerization (PN(CH2)3NP) to trimerization (PN(CH2)2NP). We managed to successfully develop the first truly selective (over 90%) 1-octene catalyst with polymer-free behavior. Further modifications on the ligand framework, where one atom of Si was used to link the two NP units, resulted in non-selective oligomerization, in which case we determined that the oxidation-state of chromium is a key player. We explored other modifications on our selective ligands in which one of the arms on the bidentate ligand was replaced with a base-donor amine, phosphine or pyridine, and resulted in interesting selectivity changes. The final modification that we tested was a novel N(CH2)2P ligand and found it to be a highly active, non-selective oligomerization catalyst.
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27

Chen, Jeng-Shiou. "Pd/C-catalyzed Suzuki cross- and self- couplings & the development of a lab-scale hydrogenation system". 2008. http://hdl.rutgers.edu/1782.2/rucore10001600001.ETD.17253.

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28

Chern, Jong-Yuan y 陳中元. "Kinetics Study of Hydrogenolysis of Chlorofluorocarbons over La1-xSrxNiO3(x=0.3,0.5) Catalysts". Thesis, 1996. http://ndltd.ncl.edu.tw/handle/61559524667299764289.

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29

CHUANG, CHEN-LUNG y 莊鎮隆. "Hydrogen Production from Steam Reforming of Ethanol over La1-x-yCexCayNiO3 Catalysts". Thesis, 2015. http://ndltd.ncl.edu.tw/handle/40479697031577384295.

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碩士
國防大學理工學院
化學工程碩士班
103
Ni catalysts have been widely investigated for the steam reforming of ethanol due to its low cost and high activity. The main drawbacks of Ni-based catalysts are their rapid deactivation resulted from the carbon deposition at low reaction temperature and the sintering of Ni particles at high temperature. The perovskite-type oxides catalysts could avoid carbon formation, and present superior catalytic activity and stability. In the present research, Ce and Ca were doped into the LaNiO3 catalyst for the resistance of coke and sinter. The catalysts were prepared by method of co-precipitation and co-precipitation oxidation w/ or w/o ultrasonic assisted. Precursors were Ni(NO3)2•6H2O, La(NO3)3•6H2O, Ce(NO3)3•6H2O, Ca(NO3)2•4H2O, using NaOH as precipitant and NaClO as oxidant, and named as La1-x-yCexCayNiO3. All samples were characterized by using XRD, TEM, BET, TPR, EA and TG techniques. The catalytic activity on the steam reforming of ethanol (SRE) reaction was evaluated in a fixed-bed reactor. The reduced La0.4Ce0.5Ca0.1NiO3 sample shows more resistance to deactivation comparing to other loadings, both oxygen vacancy and La2O2CO3 in the reaction process acted as the carbon scavenger. Stronger MSI could improve the catalyst stability in SRE.
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30

Hu, Wei-Min y 胡維民. "Nanosized La1-xA´xMnO3(A´=Sr,Ce) Catalysts for the Reaction of NO Reduction". Thesis, 2002. http://ndltd.ncl.edu.tw/handle/33jtm5.

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碩士
國立成功大學
化學工程學系碩博士班
90
The nano-particle technology is appropriate for producing high performance catalysts. These catalysts prossess a markedly higher activity and selectivity compared with the conventional ones. The catalysts can be also used for reaction at a relativity low temperature, thereby reducing energy consumption. In this study, the sol-gel method was employed to prepare the nanosized La1-xA´xMnO3 (A´=Sr,Ce) catalysts and the effects of promters ,Sr and Ce, on the characteristics and reaction activities were investigated. In the synthesis of catalyst precursor, the nitrate was reacted with PAA for 20 minutes while the pH value was controlled at 2. The precursor was then calcinaed in air at 700℃ for 4 hours to get catalyst. The catalysts prepared were characterized with XRD, BET, SEM, TEM, ESCA, TPD and TPR. The activities of catalysts for the reduction of nitric oxide with carbon monoxide as the reducing agent were evaluated by comparing the CO conversion-temperature curves. The causes for different activities were also closely examined basing on the results of catalyst characterization. Experimental results show that the activities of catalysts can be well correlated to the specific surface area, Mn atomic ratio on surface as well as the crystal phase. In the aspect of structure, the addition of Ce can raise the Mn content on the catalyst surface, but the addition of Sr gives no marked effect. The NO-TPD results indicate that the NO adsorbabilty of LaMnO3 catalyst can be enhanced by additing an appropriate amount of Sr, but adding Ce will lower the ability. The CO-TPR results reveal that the addition of Ce or Sr has no marked effect. The results of activity test indicate that partially substituting La with Sr or Ce increases the activity to reduce NO with CO as a reducing agent. An optimal substitution fraciton exists in the Sr series catalysts while a complete substituiton in the Ce series (ie. CeMnO3) gives the highest activity. In addition, we used the “IA” factor (IA = Surface area of catalyst Atomic ratio of active metal) to represent the total amount of active metal on the catalyst surface and tried to find the correlation between IA and activity of catalysts. The results reveal that NO conversion can be closely correlated to IA in these two series of catalysts. At the end of this study, a kinetic study on the NO reduction over the CeMnO3 catalyst with CO as a reducing agent was carried out to obtain a rate expression and to figure out a suitable reaction mechanism. The results show that none of three common models, Langmuir-Hinshelwood model—NO and CO adsorbed on two direffent kinds of active sites, Langmuir-Hinshelwood model—NO and CO adsorbed on the same kind of active sites, and Mars-Van Krevelen model, can fully fit the kinetic data we obtained. It means that the reaction mechanism is more complex than that we expected. Therefore, an appropriate model should be searched in the future.
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31

Chen, Zhi Bang y 陳志邦. "Analysis of catalytic and electric properties for reducing gas on La1-xSrxCoO3 perovskite oxides". Thesis, 1995. http://ndltd.ncl.edu.tw/handle/70467736942863091561.

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32

Kuo, Yen-Tien y 郭晏瑱. "Characterization of La1-xSrxMnO3 Powders and Their Catalytic Properties for the CO+NO Reaction". Thesis, 2003. http://ndltd.ncl.edu.tw/handle/23994443511142765509.

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Resumen
碩士
國立成功大學
材料科學及工程學系碩博士班
91
NOx and CO removal from the combustion exhaust gases has become a serious environmental problem. In order to reduce these pollutants both noble metals and perovskite-type catalysts have been used. Compared to noble metals being expensive and having the sintered problem, perovskite oxides have better thermal stability and are cheaper, therefore it is noticeable in the last years. The aim of this study was to synthesize the perovskite catalyst of La1-xSrxMnO3, and to investigate the influence of Sr content on the characteristics and the activity for CO+NO reaction. La1-xSrxMnO3 catalysts were prepared by the amorphous citrate method. Dopping Sr can reduce the temperature for synthesizing La1-xSrxMnO3 . The powder synthesized at 700℃ showed only one phase of La1-xSrxMnO3 perovskite for x≦0.15, and the other phases of SrCO3 for x≧0.2. The lattice parameters and specific surface area of La1-xSrxMnO3 increased and the particle sizes, crystalline sizes of La1-xSrxMnO3 decreased with an increase in the fraction of Sr. The activity of LaMnO3 catalysts can be enhanced by dopping Sr. In this study, the La0.85Sr0.15MnO3 catalyst had the highest activity and with this catalyst, the temperature for complete conversion of CO+NO could be down to 400℃. The catalyst also gave a higher conversion of CO into CO2 and NO into N2 at 400℃in the condition of CO:NO=1:2 (volume ratio). The results of temperature programmed test showed that the La1-xSrxMnO3 (x = 0 ~ 0.2) catalysts for the CO+NO reaction was an oxidation-reduction mechanism and the catalysts after catalytic reaction preserved perovskite phase.
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33

Huang, Yu-Kai y 黃聿愷. "Catalysts of A-site substituted Layered Perovskite La2-xMxTi1.7Ru0.3O7 (M = Mg, Ca, Sr) on Oxidative Steam Reforming of Ethanol". Thesis, 2019. http://ndltd.ncl.edu.tw/handle/wf549y.

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碩士
國立交通大學
應用化學系碩博士班
108
In previous study, we successfully synthesized the optimized solid solution La2Ti1.7Ru0.3O7 by sol-gel method and use it as a catalyst for oxidative steam reforming of ethanol(OSRE) reaction. In this research, we use the same method and successfully synthesized a series of La2-xMxTi1.7Ru0.3O7(M=Mg, Ca, Sr) catalysts. Due to the impurity phase RuO2 formed in La1.8Mg0.2Ti1.7Ru0.3O7, the characterization and performance study were focusing on La2-xMxTi1.7Ru0.3O7(M=Ca, Sr). According to powder X-ray diffraction(PXRD) and Rietveld structure refinement, the phase width of La2-xMxTi1.7Ru0.3O7(M=Ca, Sr) catalyst is between 0~0.2. X-ray Photoelectron Spectroscopy(XPS) and Temperature-Programmed Reduction(TPR) study indicates the relative percentage of high ruthenium oxidation state (Ru≥4+) decreased and the oxygen vacancy increased as the content of Ca, Sr increased. In the performance test, we fixed the C/O ratio at 0.7 and 300°C, and utilized OSRE reaction and 100 hour time on stream test under autothermal steam reforming of ethanol (ATRE) to evaluate the catalyst activity. In OSRE reaction, the results indicated the substitution of Ca and Sr can promote water gas shift reaction (WGS) reaction effectively. The order of WGS activity on catalysts is: La1.8Sr0.2Ti1.7Ru0.3O7 > La1.8Ca0.2Ti1.7Ru0.3O7 > La2Ti1.7Ru0.3O7. The used catalysts La1.8M0.2Ti1.7Ru0.3O7(M=Ca, Sr)/LZO and La2Ti1.7Ru0.3O7/LZO were not decomposed. The catalyst La1.8Sr0.2Ti1.7Ru0.3O7/LZO exhibits the highest ethanol conversion during the time on stream test and there is no sign of carbon deposition on used catalyst. The second part of this thesis contains the Diffused Reflectance Infrared Fourier Transform Spectroscopy (DRIFT) study on the effect of support on reaction routes of nickel catalyst under different steam/ethanol ratio. The result indicates that using La2Zr2O7 as supporting material could promote methane steam reforming and water gas shift reaction effectively, which prevent the deposition of methane and carbon monoxide on the catalyst. On the other hand, using Al2O3 as supporting material shows low activity on the conversion of C1, C2 intermediate.There are significant amount of methane, carbon monoxide, and acetate attached on the surface of catalyst at high temperature(T=450~500°C) and thus promote the probability on deactivation of the catalyst. Therefore, La2Zr2O7 is a appropriate supporting material for metal or metal oxide catalyst.
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34

Hardouin, Duparc Valérie. "Complexes de cuivre (II) portant des ligands sulfonés ou carboxylates et leur application en catalyse". Thèse, 2018. http://hdl.handle.net/1866/21696.

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