Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 16 of 16 for “"Catalyst degradation"”.
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Oxidation catalyst degradation in the exhaust stream of a large bore 2-stroke natural gas engine
… and some unburned hydrocarbons. Oxidation catalysts aid in reducing these harmful emissions. Lubrication oil carryover to engine exhaust degrades the oxidation catalyst making it less effective at reducing emissions. This work combines laboratory and field testing of an oxidative catalyst …
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Investigating the fundamentals of ring-opening metathesis polymerization to synthesize large, well-defined, bottlebrush polymers
… of the polymerization suffers due to premature catalyst degradation. Attaining large, well-defined, bottlebrush polymers requires precision so it was our goal to determine how seemingly simple reaction variables could affect the rates of propagation and achievable conversion, as well as why …
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Heterogeneous asymmetric epoxidation of cis-ethyl cinnamte over Jacobsen's catalyst immobilized in inorganic porous materials
… of the most relevant methods. However the chiral catalyst, a Manganese(lll) salen complex coexists with the reaction products in one unique phase. This makes it difficult to separate the reaction products and catalyst reusability, two key features in the drive to develop an industrial process. …
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Thermal characterisation of XB2-CA4 : cyclic poly(butylene terephthalate) with stannoxane catalyst
… cyclic butylene terephthalate with a stannoxane catalyst, which polymerises into cyclic poly(butylene terephthalate) (cPBT). When heated this material undergoes very rapid concurrent polymerisation and crystallisation. These processes were separated using a combination of two different techniques …
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Materials Characterization and Spectroscopy for a Methane Abatement Catalyst
… copper-zeolite (mordenite) methane oxidation catalyst for long-term durability and potential performance at 400 and 950 C. Using materials characterization and spectroscopy techniques including scanning-electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), …
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Evaluation of aged woodstove catalysts
… substantially after a few seasons of use, and catalyst degradation is a suspected cause. Previously, an in-field test developed to assess catalyst condition was performed on a group of catalytic stoves in field use. In the current study, a laboratory test apparatus and procedure for the …
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Novel Ignition Approaches for Improved Hydrogen Ignition
… electromechanical device enabling Pt-coated catalyst rod insertion into the chamber for testing. At 1000K, average ignition delay for hydrogen jets interacting with Pt-coated rods was 4.13ms, significantly shorter than 9.02ms for H₂ free jets and 11.3ms when interacting with uncoated rods. At …
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Multiscale computational simulation of multidimensional chemically reacting flow over washcoated heterogeneous catalysts
… temperatures, and integrate well with internal catalysts. In this work, a particular design for a ceramic microchannel reactor is evaluated. A 3D computational fluid dynamics model with conjugate heat transfer and detailed kinetics for methane steam reforming was built. The model is used to …
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Model electrode structures for studies of electrocatalyst degradation
… and fuel flexibility. The most effective catalyst in these systems consists of nanoparticles of Pt or Pt-based alloys on carbon supports. Understanding the role of the nanoparticle size and structure on the catalytic activity and degradation is needed to optimize the fuel cell performance …
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In-situ investigation and mitigation of carbon support corrosion of cathode catalyst in PEM fuel cells
… is one of the key factors causing cathode electrocatalyst (Pt/C) degradation in proton exchange membrane fuel cells (PEMFC). It is electrochemical oxidation and thus needs to be investigated in-situ with potential imposed. CSC was characterized in-situ and correlated to the Pt redox reactions and …
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In situ electron microscopy of nanomaterials dynamics in heterogeneous phase environments
… bulk support and across the support surface. The degradation of the support during particle migration was also observed in certain gas environments. In some gas environments, the particle coalescence via oriented attachment took place. These results showed that the combination of imaging modes can …
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Rapid methods for bacterial identification and predicting antibiotic resistance by MALDI-TOF MS
… focuses on the investigation of six metal oxide catalysts for effective cleavage and laser ionization of bacterial cell wall phospholipid extracts. Following evaluation of the six catalysts, CeO2 was found to be the most stable over time and reproducibly generated fatty acid profiles. A suite of …
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Auxiliary proton-influenced metal-mediated reactions: dioxygen activation, anion coordination, and catalysis
… glassy carbon electrode identify that the active catalyst species adsorbs to the electrode’s surface. A survey of the binding of anions to the unsaturated 16e– Lewis acid, [Cp*Ir(TsDPEN)]+ ([1H]+) was performed, where TsDPEN is racemic H2NCHPhCHPhNTs–, is presented in Chapter 4. The derivatives …
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Design, Synthesis and Catalytic Evaluation of Mono- and Polynuclear Organometallic Materials as Hydroformylation Catalysts
… selective and recyclable rhodium-based catalysts. The strategies of introducing hydrophilic substituents, multiple active sites and bulky dendritic ligands are currently explored to enhance catalyst performance and recyclability. This study investigated the synthesis, characterisation …
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Next-generation ionomers for proton exchange membrane fuel cells From catalyst¿ionomer interactions to membrane¿electrode assembly performance and durability
L'abstract è presente nell'allegato / the abstract is in the attachment