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 37 for “"HFC"”.
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Flashing flow of refrigerant HFC-134a through a diabatic capillary tube
… and adiabatic capillary tube, refrigerant HFC-134a flow with and without oil. The process of refrigerant flow through a capillary tube is a flashing process, in which the state of the refrigerant changes from subcooled liquid to a vapor-liquid mixture. Metastable phenomena in the flow, i.e. …
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Performance of uncooled 1.3 [mu]m FP and DFB lasers in hybrid fiber-coax (HFC) networks
Thesis (M.Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1997.
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Occupational Factors Affecting the Accommodative Response in the Human Vision System
… below 0.6 Hz and the high frequency component (HFC) measuring between 1.0 and 2.3 Hz. This thesis examined occupational factors that may affect AMFs comprising of cognitive demand, visual fatigue and the type of digital display used. These effects were measured by assessing changes in the LFC, …
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Occupational Factors Affecting the Accommodative Response in the Human Vision System
… below 0.6 Hz and the high frequency component (HFC) measuring between 1.0 and 2.3 Hz. This thesis examined occupational factors that may affect AMFs comprising of cognitive demand, visual fatigue and the type of digital display used. These effects were measured by assessing changes in the LFC, …
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Phase Equilibria and Transport Properties of Gas-Saturated Ionic Liquids
… potential (GWP) F-gases. Hydrofluorocarbons (HFCs), a particularly potent class of F-gases widely used in refrigeration and other industries, are often found in azeotropic mixtures that make their separation challenging. Extractive distillation with ionic liquids (ILs) as entrainers has …
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Hydrogeology and groundwater geochemistry of two glacigenic aquitard/aquifer systems in north-central and south-central Minnesota
… 210 ft) and at the MN Hydrogeology Field Camp (HFC; depths from 115 to 200 ft) near Akeley, MN. Transducers were emplaced to gather evidence of hydraulic head fluctuations, and groundwater samples and pore water samples from till cores were analyzed for major and trace elements, anions, …
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Engineering therapeutic proteins for immune modulation
… of human IgG1 to human Fc gamma receptors (hFcγR) is highly sensitive to the presence of a single N-linked glycosylation site at asparagine 297 (N297) of the Fc, with deglycosylation resulting in a complete loss of hFc[gamma]R binding. Thus, aglycosylated variants that can bind to …
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Fine Coal Dewatering Using Hyperbaric Centrifugation
… process called hyperbaric filter centrifugation (HFC) has been developed. This novel method combines centrifugation and pressure filtration within a single process to substantially reduce moistures over what can be achieved using conventional dewatering systems. In the current study, steady-state …
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First principles phase diagram calculations in group IV carbides and Mg2SiO4 liquid from Molecular Dynamics
… diagrams of the binary systems TiC-ZrC, TiC-HfC, ZrC-HfC at ambient pressure are computed based on electronic structure and energy calculations within density functional theory. Formation energies for a large number of supercells with compositions of (M1,M2)C, M1, M2 = Ti, Zr, or Hf, are …
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Integrated geological and petrophysical investigation on carbonate rocks of the middle early to late early Canyon high frequency sequence in the Northern Platform area of the SACROC Unit
… petrophysical analysis in high-frequency cycle (HFC) scale sequence stratigraphic framework and to improve our ability to understand static and dynamic petrophysical properties of these reservoir rock types, and there by, improve our understanding of heterogeneity in the middle early to late …
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The impact of coating architecture on the hardness, friction and wear resistance of hard and tribological nanocomposite coatings
… that form composite microstructures (WC-SiC, HfC-SiC). Hardness measurements on these films indicated the potential of transition metal carbide-silicon carbide composites to be utilized as protective coatings. With the use of a substrate bias potential, a hardness of over 35 GPa was achieved …
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Atmospheric implications of untested carbonyl photochemistry: an evaluation using chemically explicit and global 3D modelling
… has been shown to be a source of fluoroform (HFC-23) in small yields. The degradation and deposition pathways of CF3CHO were modelled using AtChem2 to provide a range of values on the production of HFC-23. The modelling estimates show that CF3CHO could contribute up to 14.7% to the current …
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Design, Testing And Controls For Air Source Heat Pump System In Cold Climates Using Natural & Conventional Refrigerants
… use various types of hydrofluorocarbons (HFC) refrigerants which are also responsible for greenhouse gas emissions. Therefore, natural refrigerant such as which is naturally available, eco-friendly, non-toxic, non-flammable, and non-corrosive can be a good alternative to the HFC …
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Asymmetric synthesis involving silicon
… <sup>1</sup>H NMR methods in the presence of Eu(hfc)<sub>3</sub>. Enantiomeric purity of some of these silyl diols is greater than 90% e.e. <br></br><br></br>Synthetically more useful, optically active trimethylsilylepoxides, trimethylsilyl amino alcohols and aziridines have been isolated by a …
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A Novel Mass Spectrometer for Atmospheric Measurements & Halocarbons During the CARIBIC and SAMBBA Aircraft Campaigns
… Hemispheric (NH) baseline values. Furthermore, HFC-134a and HFC-227ea were almost double their NH baseline. CH2Cl2, C2Cl4 and C2HCl3 were encountered at high concentrations and sources of very short-lived bromomethanes (VSLB) were identified close to London. As part of the CARIBIC project, five …
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Sustainable development of refrigerator systems using replacement environmentally acceptable refrigerants
… systems using the replacement refrigerant HFC-134a. The work focuses on the emissions that may arise if the electrical consumption of the product deteriorates or its durability is curtailed. Tribological characteristics on compressor components influence both of these product attributes and …
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Trend Analyses of the Abundances of Atmospheric Molecules
… emissions of CFC-replacement hydroflourocarbons (HFCs) has caused a dramatic increase in their atmospheric abundances. Although these HFCs do not contribute directly to the depletion of the ozone layer because they contain no chlorine, they are powerful greenhouse gases with large global warming …
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Long term trends of halogenated trace gases, hydrocarbons, alkyl nitrates and of the oxidative capacity of the atmosphere
… (halons) and greenhouse gases (PFCs, SF5CF3, HFC-227ea) are reported using measurements from Cape Grim, Tasmania. A two-dimensional global atmospheric chemistry transport model is used to derive global annual emission histories of these long lived gases. Emissions of the halons are found to …
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Flow pattern mapping of horizontal evaporating refrigerant flow based on capacitive void fraction measurements
… for two-phase flow and heat transfer studies of HFCs was designed and constructed. Secondly, a capacitive void fraction sensor was developed to study the dynamic behavior of two-phase flows. The capacitance transducer can measure dynamic signals of fluids with the capacitance of the liquid …
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Emissões de gases fluorados causadores de efeitoestufa: desenvolvimento e análise de cenários para o Brasil até 2050
… scenarios for fluorinated greenhouse gas (HFC, PFC and SF6) emissions in Brazil up to 2050, and to evaluate potentials and costs of implementing different mitigation options. For the scenario considering the highest economic growth, it is estimated that, in 2050, the emissions of …
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