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 20 of 183 for “"exothermic"”.
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The underwater application of exothermic welding.
Thesis: Ocean E., Massachusetts Institute of Technology, Department of Ocean Engineering, 1972
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Exothermic flux forge welding of steel tubulars
… and toughness property requirements. A novel exothermic flux forge welding method is introduced for solid-state welding of steel tubulars and aspects of the development are discussed including constituent and heating rate effects on self-propagating high-temperature synthesis of metal and …
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Mechanisms of instabilities of exothermic hypersonic blunt-body flows,
Thesis (Sc. D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1968.
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Exploration of the Endothermic and Exothermic Reactions of Calcium Oxide and Magnesium Oxide and Design of a Vessel for a Thermochemical Heat Storage System
… oxide (MgO) and water. In the output mode, an exothermic reaction is initiated when liquid water or steam is injected into the metal oxide particle bed to produce Ca(OH)2 or Mg(OH)2. The heat generated in this process can then be used to heat up a secondary flow of water or other heat transfer …
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A feasibility study for reset control of an industrial batch reactor
… to the temperature control loop of a pressurized exothermic batch leach reactor in the hydrometallurgical Precious Group Metals (PGM) industry is carried out. Keywords: Reset control; Clegg integrator; initial states; industrial batch reactor; temperature control; exothermic reactions; multiple …
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Control strategies for exothermic batch and fed-batch processes A sub-optimal strategy is developed which combines fast response with a chosen control signal safety margin. Design procedures are described and results compared with conventional control.
… scope for improving the temperature control of exothermic processes. In this thesis, a sub-optimal control strategy is developed through utilizing the dynamic, simulation tool. This scheme is built around easily obtained knowledge of the system and still retains flexibility. It can be applied to …
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Engineering Approximations for Chemical Kinetics
… reactions. The model works well until very exothermic or endothermic reactions are encountered. However, including a Pauli repulsion term in the derivation of the Marcus equation leads to a simple equation which does extend out to very exothermic and endothermic reactions. The new model …
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Nonlinear Dynamic Combustion of Energetic Solids
… decomposition is overall slightly exothermic (increasing with pressure) with activation energy similar to that for proton transfer between hydrazinium and nitroformate ions. The gas-phase flame is highly exothermic with low activation energy, suggesting the gas-phase process is more …
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Synthesis and analysis of reactive nanocomposites prepared by arrested reactive milling
… in detail. The correlation of heterogeneous exothermic reactions occurring in the nanocomposite powders upon their heating at low rates and ignition events observed for the same powders heated rapidly was of interest. Differential scanning calorimetry (DSC), X-ray diffraction (XRD) and heated …
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Methodology for Pyrolysis-induced Thermal Runaway Analysis in Li-ion Batteries
… electrolytes displayed a pronounced exothermic peak at 350°C, indicative of significant decomposition reactions. In contrast, the LiFSI-ether electrolyte exhibited an exothermic reaction at 210°C, followed by an endothermic event near 300°C. Such variances in thermal behavior …
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Investigating mechanical properties of ordinary portland cement. Investigating improvements to the mechanical properties of Ordinary Portland Cement (OPC) bodies by utilizing the phase transformation properties of a ceramic (Zirconia).
… immediately following the crystallization exothermic burst phenomenon in ZrO2 were measured. Thermal analysis and x-ray methods were used to determine crystallite sizes and structures immediately following the exothermic burst. Comparisons were made for zirconias prepared from oxychloride, …
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Mesoscale Computational Analysis on the Reactivity of Heterogeneous Energetic Materials with Electromechanical Properties
… analysis, wherein dielectric breakdown and exothermic reaction processes are simultaneously resolved over the nanosecond timescale based on an electrodynamic-chemical-thermal framework. Here, the breakdown process is explicitly modeled as the irreversible transition of the material from its …
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Materials development for multicomponent systems with variable oxidation states
… (cation:organic ratio), characteristics of the exothermic reaction (C/N ratio), calcination/crystallization atmosphere and temperature, were investigated. Additionally, the electrochemical performance of the LiMn2O4 (LMO4) composition was evaluated and compared against commercial LiMn2O4 …
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Synthesis and characterization of mechanically alloyed aluminum-based compounds as high energy density materials
… Al. Upon their heating, a number of subsolidus exothermic transitions were detected and assigned to formation of different modifications of Al_3Ti. For alloys with 20 at-% or less of Ti, an endothermic transition was observed around 1170K, which was assigned to the formation of aluminum and …
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The effects of natural convection on low temperature combustion
When a gas undergoes an exothermic reaction in a closed vessel, spatial temperature gradients can develop. If these gradients become sufficiently large, the resulting buoyancy forces will move the gas, i.e. there is natural convection. The nature of the resulting flow is determined by the Rayleigh …
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An improved finite-element model for simulating microwave processing of polymers and polymer-composites in a cylindrical resonant cavity
… The heat generation term arising due to exothermic chemical reactions was added to the heat conduction equation. The model can now handle thermosetting resins as well as amorphous thermoplastic polymers. The governing equations for the electromagnetic submodel are the complex, …
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Reaction Synthesis of Titanium Aluminide / Titanium Diboride in-Situ Composites
… needed to form a compound is provided by the exothermic heat of formation of the thermodynamically stable product. This type of synthesis has been used to form a variety of ceramics, intermetallics, and in-situ composites. In this work, the effects of changing the stoichiometry of the titanium …
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Asymmetric temperature and composition profiles in catalyst particles
… has been considered. For a single first order exothermic reaction with Arrhenius temperature dependence and constant thermal and mass diffusivities, asymmetric profiles for temperature and composition have been obtained, thus verifying the above contention.
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Structural characterization of polyurethane foam and implications of aging
… with IR finding, where endothermic and exothermic events could be associated with chemical changes in the foam.
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ΜΟΝΤΕΛΟΠΟΙΗΣΗ ΤΗΣ ΠΥΡΟΛΥΣΗΣ ΛΙΓΝΟΚΥΤΤΑΡΙΚΩΝ ΥΛΙΚΩΝ
… AN ENDOTHERMIC ONE (FOR LOW CONVERSION) AND AN EXOTHERMIC ONE (FOR HIGH CONVERSION).
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