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 80 for “"Spallation"”.
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Interfacial spallation/delamination properties of self-assembled monolayers
… study how the presence of SAMs affects (i) the spallation strength and (ii) the fracture toughness of the interface. The modeling work summarized in this thesis is motivated by previous results of molecular dynamic (MD) simulations and laser-induced spallation/delamination tests to quantify the …
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An analysis of the spallation of carbon phenolic ablators
The phenomenon of spallation, a process by which pieces of char "pop off" a heat shield, has been investigated as it occurs in carbon-reinforced phenolic ablators. Spallation is shown to be the result of a pressure buildup within the char. This pressure increase results from occlusion of the char …
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Measurement of spallation residuals in mercury for accelerator facility targets
… cross sections of 53 medium and longer-lived spallation residuals using gamma spectroscopy at various decay times up to a year were determined. The measured cross sections were then compared with predicted cross sections from the MCNPX code. After acquisition of the gamma spectroscopy data the …
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Dose coefficients for radionuclides produced in a spallation neutron source
… U.S. Department of Energy complex, including the Spallation Neutron Source (SNS) and Accelerator Production of Tritium (APT) Projects.
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Hydrothermal spallation drilling and advanced energy conversion technologies for Engineered Geothermal Systems
… of the thesis was the application of thermal spallation drilling to deep boreholes. Thermal spallation is the fragmentation of a brittle solid into small, disc-like flakes by rapidly heating a confined fraction of the rock. It was proposed that the necessary temperatures and heat fluxes needed …
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Analysis of rock mechanics and gas dynamics of flame-jet thermal spallation drilling
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemical Engineering, 1986.
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Feasibility Study of a Natural Uranium Neutron Spallation Target using FLiBe as a Coolant
… as a coolant with a natural uranium neutron spallation source applied to an accelerator driven sub-critical molten salt reactor. The study utilized two different software tools, MCNPX 2.6 and FLUENT 12.1. MCNPX was used to determine the neutronics and heat deposited in the spallation target …
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Monte Carlo calculation and analysis of neutron and gamma fields at spallation neutron sources for simulating cosmic radiation
… at The Svedberg Laboratory (TSL) both provide spallation neutron source for radiation testing of electronic components. A local beam monitoring system was successfully developed by S. Platt and L. Zhang in the University of Central Lancashire for measuring neutron dosimetry during accelerated …
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Understanding Mechanisms of Water Lead Contamination by Nitrate Spallation Corrosion and Lead Removal by Point-of-Use (POU) Filters
… entitled A Novel Mechanism of Lead-Tin Solder Spallation in the Presence of Nitrate describes how 1) nitrate is extremely corrosive to lead:tin solder galvanically connected to copper, 2) nitrate corrosion can sometimes cause detachment of solder chunks to water, and 3) nitrate corroded the …
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Computational modeling of the gas-phase transport phenomena and experimental investigation of surface temperatures during flame-jet thermal spallation drilling
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemical Engineering, 1989.
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Target Design and Optimizations for Spent Fuel Transmutation
… substantial number of secondary neutrons through spallation interactions with target materials. The secondary neutrons produced from the spallation process are utilized by the LLFP materials, while surrounding blanket materials are selected to enhance the transmutation efficiency. PHITS, a Monte …
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Advancing Fundamental Understanding of Lead-Tin Solder Corrosion in Drinking Water: Nitrate Spallation Mechanism, Inhibition by Zinc Orthophosphate and Free Chlorine, and Implications for Canned Foods
… with very high LCR action level exceedances, 2) spallation of metallic solder to water is a source of lead contamination, 3) zinc orthophosphate offers superior corrosion control to mitigate nitrate attack, and 4) free chlorine can inhibit solder corrosion by electrochemical reversal. These …
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Characterization of carbon ablators for hypersonic thermal protection systems
… on two key ablation mechanisms: oxidation and spallation. Initial experimental bulk characterization of carbon ablatives was conducted in high-enthalpy inductively coupled plasma (ICP) wind tunnels. FiberForm and carbon fiber weaves were exposed to high-temperature plasma in the Plasmatron …
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A Study of High Temperature Corrosion in an AFBC System
… for the testing. A small amount of scale spallation was observed on the other three samples in both test runs. Based on the SEM-EDX mapping results, there was no localized chloride distribution observed on the surface of the coupons, neither in the scale spallation area nor on the rest of …
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The effect of sintering and CMAS on the stability of plasma-sprayed zirconia thermal barrier coatings
… stiffening on the driving force for spallation of plasma-sprayed (PS) TBCs was investigated. Spallation lifetimes of TBC specimens sprayed onto alumina substrates were measured. A simple fracture mechanics approach was employed in order to deduce a value for the strain energy release …
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Desarrollo de criterios nucleares de diseño de fuentes de neutrones de espalación
Abastract Spallation neutrón sources allow obtaining high neutronic flux for many applications, scientific or industrial. Due to this, in recent years, several proposals have been made where its use is suggested, among which should be highlighted the European Spallation Source (ESS), the Japanese …
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An Improved Flexible Neutron Detector For Powder Diffraction Experiments
… to the construction of the next generation of spallation sources for neutron scattering. Neutron powder diffraction instruments will be an important element of these facilities and the incorporation of detectors into these instruments with a high neutron capture efficiency is desirable. A new …
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Non-Neutron Transmutation of Spent Fuel
… proton beam energy to take advantage of proton spallation reactions may be successful, especially in the case of Selenium79. 660g/year of Selenium-79 are produced in a 1 GW (thermal) reactor. Initial spallation estimates show that for Selenium-79, approximately 24 g/year could be transmuted with …
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