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 17 of 17 for “"chlorofluorocarbons"”.
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The model lifetimes, band intensities, growth scenarios and atmospheric implications of substitute chlorofluorocarbons
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 1990.
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Trace gases in Antarctic and Greenland firn and ice: a record of carbonyl sulphide and the isotopologues of chlorofluorocarbons
… reaction and transport pathways of the man-made chlorofluorocarbons (CFCs) could help us to mitigate their destructive effect. Previous studies have found that both source and sink processes significantly alter the isotopic composition of trace gases (e.g. N2O and CFC-12). Measuring these changes …
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Heat transfer and flow characteristics of condensing refrigerants in small-channel cross-flow heat exchangers
… continues to rise due to the phase out of chlorofluorocarbons (CFCs), internal volume becomes a key design parameter.
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Thermochemistry and kinetics: hydrogen atom addition reactions with alkenes, oxidation of cyclopentadienone, trifluoroethene and transport properties
… calculation method for use on large molecules. Chlorofluorocarbons are widely present in the environment. Thermochemical and kinetic properties work will aid in the understanding the chlorofluorocarbons reactions in combustion and atmospheric environments. Trifluoroethene (CF_2=CHF) reaction in …
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A study of North Atlantic ventilation using transient tracers
… distributions of tritium 3H), 3He, and the chlorofluorocarbons (CFCs) can be used to constrain the time-scales of the major ventilation pathways for an ocean basin such as the North Atlantic. I present a new global model function, developed from a factor analysis of the WMO/IAEA data set, …
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Coordination Cages as a Scaffold for Permanently Porous Liquids
… also dissolved and encapsulated three different chlorofluorocarbons. Additionally, we also present the first hetero-cage, which we define to be a coordination cage that is charge-balanced by a second, different cage of opposite charge. A hetero-cage was synthesized by charge-balancing a liquid …
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Age of air and the circulation of the stratosphere
… chemical species, including ozone-depleting chlorofluorocarbons. Age of air in the stratosphere is an idealized tracer with unique mathematical properties, which we exploit to derive a theory for the relationship of tracer observations to the stratospheric circulation. We show that the …
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Perchlorate Variations Over 300 Years: Influence of Human Activities, Volcanic Eruptions and Bolide Events
… of chlorine-containing compounds, including chlorofluorocarbons (CFCs), are likely indirectly responsible for approximately two-thirds of the perchlorate present in the current environment. Variations in perchlorate concentrations suggest that natural perchlorate production occurs in the …
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EXAMINATION OF PHOTOCHEMISTRY AND METEOROLOGY OF ATMOSPHERIC POLLUTANTS FROM THE NORTH CHINA PLAIN
… provide a critical opportunity to characterize chlorofluorocarbons (CFCs) over a suspected CFC-11 source region in China, finding mixing ratios were well above 2016 global background levels. Based on correlations of CFCs with compounds used in their manufacture, I identify likely source regions …
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Age of air and the circulation of the stratosphere
… chemical species, including ozone-depleting chlorofluorocarbons. Age of air in the stratosphere is an idealized tracer with unique mathematical properties, which we exploit to derive a theory for the relationship of tracer observations to the stratospheric circulation. We show that the …
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Tracing Wyville Thomson Ridge Overflow Water in the Rockall Trough
… time. Using a variety of chemical tracer s (chlorofluorocarbons, oxygen, nutrients and aluminium) in conjunction with temperature and salinity, WTOW is traced southwards into the northern and central Rockall Trough as well as into the channels between the western banks. The overflow water has …
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Understanding Drivers of Stratospheric Ozone Change and Fingerprinting its Recovery
… ODSs. Chapter 2 examines the ocean’s uptake of chlorofluorocarbons (CFCs), particularly emphasizing its influence on recent illicit CFC emissions estimation. Chapter 3 extends this analysis to include ocean uptake and potential microbial degradation processes, evaluating their effects on …
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An Investigation of the Distribution of Ozone-depleting Substances in the Upper Troposphere and Lower Stratosphere
Stratospheric transport in global circulation models and chemistry-climate models is an important component in simulating the recovery of the ozone layer as well as changes in the climate system. The Brewer-Dobson Circulation is not well constrained by observations and further investigation is …
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Assessment of the environmental acceptability of refrigerants by discrete mathematics: cluster analysis and Hasse diagram technique
… of the adverse environmental impact of chlorofluorocarbons (CFCs), mainly used as refrigerants, has lead to look for environmentally acceptable CFC replacements. Main environmental concern CFCs face is their ability to deplete the stratospheric ozone layer, quantified by the ozone …
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A Multi-Scale analysis of organochlorine pesticide contamination in raptor populations: research effort, historical trends, and current concentrations
… radiation by banning chemicals such as CFCs (chlorofluorocarbons). These success stories provide hope that other global crises such as climate change and biodiversity loss can benefit from well planned and implemented local and global agreements. Furthermore, the benefits of using raptors as …
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Constraining the North Atlantic circulation with transient tracer observations
The capability of transient tracers to constrain the ocean circulation in the North Atlantic is explored. Study of an idealized tracer shows that inferences of circulation properties from transient state distributions are impacted by uncertainties in the time-varying boundary conditions and sparse …