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 8 of 8 for “"tetrafluoroethane"”.
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Reactive Plasma Etching of Silicon Carbide, Silicon Carbonitride, and Titanium Nitride in a Tetrafluoroethane/Oxygen Plasma
… the RF plasma and the magnetron gun with 1,1,1,2 tetrafluoroethane and oxygen as the active gases, we will obtain a reliable and reproducible method for determining the maximum etch rate for the various materials. An etch is required in order for a proper ground contact with the substrate. Si and …
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Analysis of Ethoxyquin and its Oxidation Products using Supercritical Fluid Extraction and High Performance Liquid Chromatography with Chemiluminescent Nitrogen Detection
… carbon dioxide, trifluoromethane, and 1,1,1,2-tetrafluoroethane. Carbon dioxide appeared to react with ethoxyquin during the extraction. Methanol modified hydrofluorocarbons provided more complete extractions over pure hydrofluorocarbon fluids. Methanol modified 1,1,1,2-tetrafluoroethane was …
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Lithiation of Oxy-Arenes; New Methodology for Electrophilic Aromatic Substitutions: Attempted Synthesis of Thiaheptalenes and Heterocyclic Pyrene Systems
… New reagents, 1,2-dibromo- and 1,2-dichloro-tetrafluoroethane were used for the halogenation of the lithiated positions. These remote lithiation reactions are useful in the synthesis of theoretically interesting heterocyclic heptalene and pyrene systems.
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Developing Adiabatic Two-Phase Flow
… study was performed using H2FC-CF 3 - 1,1,1,2-Tetrafluoroethane (R134A) as a working fluid in three different transparent tubes. The flow was visualized using a high speed camera. To better (faster and more objectively) analyze the flow, a technique was developed to determine the separation …
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Rheology of molten polystyrene with dissolved gases
… 1,1-difluoroethane (R152a), and 1,1,1,2- tetrafluoroethane (Rl34a), which are considered to be environmentally acceptable for replacing previous ozone-depleting hydrochlorocarbon (HFC) refrigerants. A modified pressurized capillary rheometer was employed for the viscosity measurement of …
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Supercritical fluid extraction as a sample preparation technique for the isolation of polar pharmaceutical compounds
… fluids (pure and modified fluoroform and tetrafluoroethane), 2) pre-extraction, and 3) selective rinsing of the solid phase trap. Advantages were realized with each technique, and it was concluded that they be used in conjunction with one another in order to maximize selectivity.
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Comparative Life Cycle Assessment of CFC-replacement Compounds in Different Technical Applications
… are compared with the presently used 1,1,1,2-tetrafluoroethane (R134a). Additional refrigerants included in this study comprise dichloromethane (R30), propane (R290), isobutane (R600a), carbon dioxide (R744), pentafluorodimethyl ether (E125), 1,1,1’,1’-tetrafluorodimethyl ether (E134), …
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Flash gas bypass concept utilizing low pressure refrigerants
Flash gas bypass represents one of the prospective approaches to improve the efficiency of various small scale heat transfer systems that utilize refrigerant as a working fluid. It is characterized by the bypass of vapor created throughout the expansion process around the evaporator. As the …