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Dissertations / Theses on the topic 'Chlorofluorocarbons'
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1
Bateman, Alison Sian. "Chlorofluorocarbons in groundwater." Thesis, University of East Anglia, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.285224.
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Berrey, Christopher Lee. "Catalytic reactions involving chlorofluorocarbons : a review /." Master's thesis, This resource online, 1995. http://scholar.lib.vt.edu/theses/available/etd-10242009-020132/.
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Jeansson, Emil. "Chemical tracers in the Nordic Seas : studies on water masses and anthropogenic carbon /." Göteborg : Göteborg University, Department of Chemistry, 2005. http://www.loc.gov/catdir/toc/fy0801/2006421403.html.
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4
Dalamagas, Demetra G. "The effects of varying concentration and duration of CFC-113 exposure on end-exhaled breath CFC-113 concentration." Morgantown, W. Va. : [West Virginia University Libraries], 1999. http://etd.wvu.edu/templates/showETD.cfm?recnum=411.
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Thesis (M.S.)--West Virginia University, 1999.Title from document title page. Document formatted into pages; contains viii, 105 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 68-69).
5
Frantzen, Michelle E. Gunn. "Abatement of perfluorocompounds and chlorofluorocarbons using surface wave plasma technology." Texas A&M University, 2005. http://hdl.handle.net/1969.1/4734.
Full textAbstract:
Application of surface wave plasma technology for effective abatement of
environmentally harmful gases such as perfluorocompounds and chlorofluorocarbons is
investigated. Perfluorocompounds (PFCs) are gases that contribute to forced global
warming and have been favored for wafer etch and chamber clean applications in the
semiconductor industry. Chlorofluorocarbons (CFCs) are ozone depleting gases that
were used as refrigerants for commercial and domestic condensers and air conditioners,
but current reserves still pose threats to environmental sustainability. Increased average
global temperatures and further destruction of the ozone layer have prompted proposal
of international initiatives such as the Montreal Protocols and the Kyoto Agreement to
curtail emissions of such fugitive gases into the environment. These have increased the
need for effective abatement technologies to control such emissions and include surface
wave plasma abatement, the subject of this dissertation. Surface wave plasmas are
considered high frequency non-equilibrium traveling wave discharges in contrast to the
more frequently used standing wave discharges. The use of surface wave plasmas have
the advantages of a variety of discharge vessel shapes, reproducibility of application, numerous operating conditions and large plasma volumes which ultimately produce low,
molecular weight byproducts that are associated with high effective electron
temperatures but low heavy particle temperatures. For these reasons, surface wave
plasma abatement technology was developed for the destruction and removal of PFCs
and CFCs.
Results include final destruction and removal efficiencies (DREs) for
octafluorocyclobutane greater than 99.8%, dichlorodifluoromethane greater than
99.995% and trichlorofluoromethane greater than 99.999% using moderate applied
microwave powers of less than 2000 watts with the production of low molecular weight
byproducts, such as CO2, CO, HF and HCl, that prevent environmentally harmful
process emissions from entering the atmosphere. Characterizations of the initial and
final products were accomplished by the use of Fourier transform infrared spectroscopy
and quadrupole mass spectrometry to provide independent quantitative analyses of
plasma processes. In addition to these analytical methods, Global_Kin a kinetic model,
of plasma reactions were conducted and compared to all the experimental data
determined in order to facilitate understanding of the chemistry involved in the surface
wave plasma abatement applications studied. Basic plasma reaction mechanisms were
determined for the abatement of octafluorocyclobutane and dichlorodifluoromethane.
6
Conqueror, Martin Robert. "Reactions of silicon intermediates relevant to the dechlorination of chlorofluorocarbons." Thesis, University of Leicester, 1994. http://hdl.handle.net/2381/34058.
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The threat to the Earth's ozone layer posed by chlorofluorocarbons (CFCs) arises because of the photolytic generation of chlorine atoms in the stratosphere. New methods of rendering CFCs less harmful by dechlorinating them, are therefore of environmental importance. Preliminary investigations have suggested that silylene chemistry may be useful in this respect. Silylenes have also been shown to be formed as gas-phase intermediates during the Direct Synthesis of methylchlorosilanes. This work reports on a study of the possibility of using these silylenes for the dechlorination of CFCs using the technology of the Direct Synthesis, and the effect that CFCs would have upon methylchlorosilane product distribution. The gas-phase reactions of silylenes with chlorofluorocarbons were studied. Silylenes (:SiMe2, :SiMeCl and :SiCl2), were generated thermally from appropriate disilane precursors in the presence of halomethanes (CF2Cl2 and CFCl3). The reactions proceeded via radical mechanisms, initiated by the decomposition of an adduct formed between the CFC and silylene, resulting in chlorine abstraction to yield chlorosilyl and halomethyl radicals. Abstraction proceeded most efficiently with :SiMe2. The mechanisms were propagated by the resultant halomethyl radicals which acted as chain carriers. Although silylene insertion reactions were observed, radical reactions were dominant. The reactions of silylenes with methyl chloride were also studied but were found to be less extensive, with die greater strength of the C-Cl bond allowing insertion reactions to become competitive. All reactions were found to proceed much more efficiently in the presence of a relatively weak Si-H bond. To understand further the role of radical reactions in the dehalogenation of CFCs, silyl radicals were generated directly using mercury photosensitisation. Similar mechanisms were indicated, although reaction was more extensive as a result of the increased number of gas-phase radical species. A laboratory scale reactor was used to simulate the addition of CFCs to the Direct Synthesis, and to study their effect on product distribution. Surface reactions dominated, with the adsorption of CFCs leading to greater chlorination of the methylchlorosilane products.
7
Lee, Julia Margaret. "Determination of stratospheric lifetimes of HCFCs and other halogenated hydrocarbons from balloon-borne profile measurements." Thesis, University of East Anglia, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.238852.
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Zhang, Hongxia. "Study of the effect of gold, platinum and vanadium oxide additives on the activity of TiO₂-ZrO₂ mixed oxide for the decomposition of CFC-22." HKBU Institutional Repository, 2002. http://repository.hkbu.edu.hk/etd_ra/367.
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Beegle, Cynthia Juyne. "Modelling the chlorofluorocarbon transient in the north Pacific : comparison with observations and model dynamics /." Thesis, Connect to this title online; UW restricted, 1995. http://hdl.handle.net/1773/11059.
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Hu, Chengjiu. "Investigation of factors influencing the development of pressurized metered dose inhalers /." Digital version accessible at:, 1999. http://wwwlib.umi.com/cr/utexas/main.
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11
Sohn, Alexander H. 2173675. "Field Emissions of (Hydro)Chlorofluorocarbons and Methane from a California Landfill." DigitalCommons@CalPoly, 2016. https://digitalcommons.calpoly.edu/theses/1686.
Full textAbstract:
A comprehensive field investigation was conducted at Potrero Hills Landfill (PHL) located in Suisun City, California to quantify emissions of twelve (hydro)chlorofluorocarbons (i.e. F-gases). The specific target constituents for this study included CFC-11, CFC-12, CFC-113, CFC-114, HCFC-21, HCFC-22, HCFC-141b, HCFC-142b, HCFC-151a, HFC-134a, HFC-152a, and HFC-245fa. The majority of the F-gas emission studies have been conducted outside of the United States and very limited field landfill emission data are available in the United States. Because of historical usage of blowing agents in insulation foams including CFC-11, HCFC-142b, HFC-134a, and HFC-245fa, models reported in literature predicted high F-gas emissions from a landfill environment, but very limited field data are available to verify such predictions.
In this investigation, the surface flux of the twelve F-gases, methane, and carbon dioxide was quantified from various landfill cover systems and in areas with different waste ages, waste heights, and cover thicknesses at Potrero Hills Landfill. In addition, destruction efficiencies for the twelve F-gases were determined based on inlet and outlet concentrations of the onsite flare system. Lastly, the surface flux values were scaled up to a facility-wide emission value to estimate the total fugitive emissions from the landfill.
The F-gas flux values for the daily covers were in the 10 -8 to 10-1 g m-2 day -1 range and 10-7 to 10-2 g m-2 day-1 range for the wet and dry season, respectively. The F-gas flux values for the intermediate covers in the -10-6 to 10-4 g m-2 day-1 range and -10-6 to 10-4 g m-2 day-1 range for the wet and dry season, respectively. The F-gas flux values for the final covers were in the 10-7 to 10-5 g m-2 day-1 range and -10-7 to 10-6 g m-2 day-1 range for the wet and dry season, respectively. F-gas fluxes for the final covers had the highest number of below detection limit cases as well as lower than R2 threshold cases. Thest F-gas fluxes were measured from daily cover system constructed with auto shredder residue (i.e. auto fluff) for the both the wet and dry seasons. The highest fluxes were measured for CFC-11, HCFC-21, and HCFC-141b in the wet season and for CFC-11, HCFC-141b, and HFC-134a in the dry season across the seven cover locations.
Lower level of variation was observed for methane and carbon dioxide with flux values ranging over five orders of magnitude for the seven tested locations. The methane flux values for the daily covers were in the 10-2 to 10+1 g m-2 d-1 range and 1 to 10+1 g m-2 day-1 range for the wet and dry season, respectively. The carbon dioxide flux values for the daily covers were in the -10+1 to 10+2 g m-2 day-1 range and -10+1 to 10+1 g m-2 day-1 range for the wet and dry season, respectively. The methane flux values for the intermediate covers were in the -10-2 to 10+1 g m-2 d-1 range and -10-3 to 10+1 g m-2 day-1 range for the wet and dry season, respectively. The carbon dioxide flux values for the intermediate covers were in the 1 to 10+2 g m-2 day-1 range for both seasons. The methane fluxes for the final cover were -10 -3 g m-2 day-1 and 10-4 g m-2 day-1 for the wet and dry season, respectively. The carbon dioxide flux values for the final cover were in the 10+1 g m-2 d-1 range and 1 to 10+1 g m-2 day-1 range for the wet and dry season, respectively. Negative flux values were typically observed during the wet season and at the intermediate and final covers.
The destruction efficiencies for the twelve F-gases were above 99.5% for the onsite flare. Highest F-gas raw gas concentrations were measured for HFC-134a while the lowest F-gas concentration was measured for CFC-113. The F-gas concentrations in the raw gas ranged from 103 to 106 pptv. Similar to what has been reported in the literature, the landfill gas flare system was an efficient abatement device in controlling F-gas emissions.
The surface emission measurement values from the field investigation were scaled up to estimate facility-wide fugitive emission values using the relative surface areas of the daily, intermediate, and final cover distributions in the landfill. The total fugitive emissions from the landfill including twelve F-gases, methane, and carbon dioxide ranged from 6,900 to 94,000 CO2E tonnes per year during the wet season, from 21,000 to 47,000 CO2E tonnes per year during the dry season, and from 13,000 to 75,000 CO2E tonnes per year during the year, prorated by the season (representing weighted average of 58% wet season emission rate and 42% dry season emission rate in a 12-month calendar year). The total fugitive F-gas emissions ranged from 1,600 to 4,800 CO2E tonnes per year during the wet season, from 140 to 600 CO2E tonnes per year during the dry season, and from 1,000 to 3,000 CO2E tonnes per year, prorated by the season. The total fugitive methane emissions ranged from 530 to 75,000 CO2E tonnes per year during the wet season, 17,000 to 35,000 CO2E tonnes per year during the dry season, and from 7,500 to 58,000 CO2E tonnes per year, prorated by the season. The total fugitive carbon dioxide emissions ranged from 5,000 to 14,000 CO2E tonnes per year during the wet season, 4,200 to 12,000 CO2E tonnes per year during the dry season, and from 4,500 to 13,000 CO2E tonnes per year, prorated by the season. In comparison to the total fugitive emission value derived from the first-order decay (FOD) model reported by USEPA and the total fugitive emission values calculated using waste-in-place (WIP) – landfill gas correlation equation presented in Spokas et al. (2015), the field-derived methane emission values were one to three orders of magnitude lower.
12
Gunnare, Sara. "Fluorinated hydrocarbons used as refrigerants : toxicokinetics and effects in humans /." Stockholm, 2007. http://diss.kib.ki.se/2007/978-91-7357-231-6/.
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Gurney, Kevin Robert. "The model lifetimes, band intensities, growth scenarios and atmospheric implications of substitute chlorofluorocarbons." Thesis, Massachusetts Institute of Technology, 1990. http://hdl.handle.net/1721.1/52912.
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Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 1990.Includes bibliographical references (leaves 31-32).
by Kevin Robert Gurney.
M.S.
14
Jachim, Jenny Ann. "The examination of the effect of three water soluble fluxes on biased comb patterns exposed to high humidity or condensing environments." Thesis, Georgia Institute of Technology, 1994. http://hdl.handle.net/1853/19573.
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15
Lee, Bing-Sun. "Uses of chlorofluorocarbons as ocean tracers and for estimating the removal rates of CFC-11 and carbon tetrachloride in certain marine environments /." Thesis, Connect to this title online; UW restricted, 1998. http://hdl.handle.net/1773/11048.
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16
Morgan, Geraint Huw. "The role of silicon intermediates in the pyrolysis of oligosilanes and the dehalogenation of chlorofluorocarbons." Thesis, University of Leicester, 1992. http://hdl.handle.net/2381/33822.
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The pyrolysis mechanisms of the oligosilanes, octamethyltrisilane, n-decamethyltetrasilane, i-decamethyltetrasilane and 2,2-diethylhexamethyltrisilane were studied using the batch stirred flow technique. Product analysis by GC/MS-SFR and kinetic studies on the major products revealed that the thermolysis mechanisms were primarily radical in nature with product formation being dependent on the balance between bimolecular and unimolecular reactions. Detailed mechanisms are proposed for major product formation and their feasibilty is assessed by computer simulation by numerical integration. Numerical integration is also used to rationalise previous discrepancies between computer modelling and experiment. Recent developments in the thermochemistry of organosilicon compounds have been successfully applied to the isomerisation mechanisms of tetramethyldisilene and methyltrimethylsilylsilylene. The use of silicon intermediates to dehalogenate CFCs is studied in detail. Thermal sources of silylenes, silyl radicals and silenes are utilised to study their affect on Freon-11, Freon-12 and Freon-13. The Mercury photosensitisation of trimethylsilane is used to generate low temperature silyl radicals which react with the Freons in a radical chain reaction. A study into the possible applications of this chemistry to the Direct Synthesis, the industrial process for methylchlorosilane production, is discussed. The gas phase pyrolyses of the methylchlorosilanes Me2SiCl2 and MeSiCl3 are investigated. GC/MS product identification was supplemented by detailed kinetic experiments and simulation of the proposed thermolysis mechanisms by numerical integration. These suggested that the thermal decomposition was initiated by a radical mechanism though silylene insertions played a role in product composition. The kinetics for the major products formed in the pyrolysis of Tetraethoxysilane are studied. These are discussed along with previously proposed mechanisms for pyrolysis. The formation of the major product ethene is believed to be formed by a number of routes including molecular and b-elimination. The Arrhenius parameters for ethanol and acetaldehyde formation suggest a heterogeneous reaction mechanism at the lower end of the temperature range studied.
17
Allin, Samuel. "Trace gases in Antarctic and Greenland firn and ice : a record of carbonyl sulphide and the isotopologues of chlorofluorocarbons." Thesis, University of East Anglia, 2015. https://ueaeprints.uea.ac.uk/57214/.
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Through the industrial revolution of the last 250 years, trace gases have had a significant impact on the climate. Of particular relevance to this work are species which facilitate the destruction of stratospheric ozone. In this thesis, I focus on four of these species. Understanding the release, 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 can be used to better constrain the interaction of these gases with the atmosphere. Atmospheric histories of δ(37Cl) and δ(13C) in CFC-11, CFC-12 and CFC-113 are presented, covering the last 20 – 60 years. Air samples came from Greenland (NEEM) and Antarctic (Fletcher Promontory) polar firn, with additional samples taken from an archive of Southern Hemispheric background air (Cape Grim, Tasmania). This study extends the novel approach to measuring trace gas isotope ratios in small air volumes (200 – 600 ml), using a single-collector gas chromatography-mass spectrometry system. Carbonyl sulphide (COS) is the principal source of sulphur in the stratosphere, where it breaks down into sulphate aerosol which catalyses the destruction of ozone. Air was extracted from Greenland (NEEM) and Antarctic (DE08, DML (BAS) and DSS) ice core samples and analysed for COS and a range of other trace gas mole fractions. The COS measurements were affected by a previously unknown post-extraction growth effect, leading to higher than expected values. This study also presents new COS measurements in firn air from NEEM and the Southern Hemisphere (EDML, Antarctica). The observed increase and subsequent decrease largely reflects changes in anthropogenic emissions during the 20th century. These measurements also indicate that regional and site-specific effects have a significant influence on the recorded atmospheric history of COS.
18
Min, Dong-Ha. "Studies of large-scale intermediate and deep water circulation and ventilation in the North Atlantic, South Indian and Northeast Pacific Oceans, and in the East Sea (Sea of Japan), using chlorofluorocarbons as tracers /." Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 1999. http://wwwlib.umi.com/cr/ucsd/fullcit?p3035926.
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LAUFFER, FRIANT ARMELLE. "De l'ozone aux c. F. C. : approche industrielle." Nancy 1, 1993. http://www.theses.fr/1993NAN1P073.
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Evans, Richard M. "Solubilization of drugs within chlorofluorocarbon based pressurized aerosols." Thesis, Cardiff University, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.308655.
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Assunção, João Vicente de. "Viabilidade e importância da redução da emissão de clorofluorcarbonos (CFCS) por reciclagem e controle no uso." Universidade de São Paulo, 1993. http://www.teses.usp.br/teses/disponiveis/6/6134/tde-19072016-173236/.
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Uma pesquisa de campo foi conduzida para verificar as condições reais de utilização de clorofluorcarbonos em sistemas de refrigeração e de condicionamento de ar. A pesquisa cobriu os setores de refrigeração de supermercados, ar condicionado de edifícios e oficinas de reparação e de manutenção de geladeiras, \"Freezers\" e condicionadores de ar compactos e automotivos. A região escolhida para a pesquisa está localizada no município de São Paulo, tendo uma superfície de 12,504 Km2. As seguintes conclusões principais resultaram deste estudo: Predomina o consumo do HCFC 22 nos usuários pesquisados; a reciclagem e a recuperação ocorrem em pequena escala na região estudada; os sistemas de condicionamento de ar automotivos são a fonte mais significativa de substâncias agressivas à camada de ozônio, nos usuários pesquisados; vazamentos ocorrem por práticas de serviço não adequadas; a utilização do CFC 11 para limpeza de circuitos reduz o ganho obtido em sistemas que empregam o HCFC 22; a manutenção preventiva mostrou ser eficaz tanto para reduzir o consumo de gás refrigerante, como para reduzir a substituição de peças e componentes; a reciclagem e a recuperação do gás refrigerante tem efeito positivo em relação à camada de ozônio, economiza recursos naturais, reduz o consumo de energia, os riscos ao meio ambiente e à saúde da comunidade em geral. Finalmente, são feitas recomendações para o estabelecimento de um programa efetivo de reciclagem e recuperação de gases refrigerantes.A field study was performed for verifying the actual conditions of the use of chlorofluorcarbons in refrigeration and air conditioning systems. The study has covered the sectors of supermarket refrigeration, building air conditioning systems, and refrigerators freezers and compact and automobile air conditioning systems repair shops. The region chosen for this study is located in the city of Sao Paulo and it has an area of 12.504 km2. The following conclusions resulted from the study: There is a predominance of the of HCFC 22 in the systems surveyied; recycling and recuperation are used in small scale in the region of the study; in the users covered by the study, the automobile air conditioning sector is the most important source of emission of ozone depleting substances; leaks occur because of bad service practices; the use of CFC 11 for circuit cleaning decreases the the gain obtained with the use of HCFC 22; the preventive maintenance has proved to be very efficient both for reducing the consum of refrigeration gases and for reducing the consum of parts and components of the refrigeration system; recycling and recuperation of refrigeration gases have positive effects in relation to the ozone layer, it saves natural resources, and reduces the risk to the enviromnent and to the public health. Finally, recommendations are made for the establishment of an effective refrigerant conservation program.
22
Bocquet, Christophe. "Les aérosols : problèmes toxicologiques posés par les chlorofluorocarbones et les produits de remplacement." Paris 5, 1990. http://www.theses.fr/1990PA05P127.
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Auffhammer, Maximilian. "Essays in environmental and regional economics /." Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 2003. http://www.gbv.de/dms/zbw/557733669.pdf.
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DEBEAUVAIS, ISABELLE. "Etude comparee de l'action de sprays refrigerants, avec ou sans chloro-fluoro-carbones, employes en traumatologie du sport et en cosmetologie : effet refrigerant et hyperemie reactionnelle." Amiens, 1989. http://www.theses.fr/1989AMIEM079.
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Lancelin, H. "Developpement d'une methode instrumentale d'analyse de composes chlorofluorocarbones sous forme vapeur dans l'air par spectroscopie resolue dans le temps de plasma induit par laser." Paris 6, 1995. http://www.theses.fr/1995PA066133.
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L'objectif principal de l'etude est de determiner les parametres essentiels conduisant a l'identification des toxiques de guerre et de definir les limites de sensibilite pour tous les atomes susceptibles de permettre leur identification (soufre, phosphore, fluor, chlore, arsenic) par spectrometrie resolue dans le temps de plasma induit par laser. Notre demarche nous a conduit a mettre en place un outil metrologique autour d'un reacteur a l'interieur duquel est simulee une pollution atmospherique sous la forme de molecules chlorofluorocarbonees. Nous avons montre que les transitions spectrales du fluor et du chlore qui offrent la plus grande sensibilite sont respectivement la 3s#4p#5#/#2-3p#4d#0#7#/#2 (1#f: 685,604 nm) et la 4s#4p#5#/#2-4p#4d#0#7#/#2 (1#c#l: 837,594 nm). Apres avoir determine l'intervalle energetique de reproductibilite de la formation du plasma (50-250 mj), nous avons montre que la mesure spectrale sur le plasma presente une excellente reproductibilite. A forte concentration ainsi qu'a faible concentration en cf#4, l'augmentation de l'energie laser permet d'exalter les raies d'emission. Cependant on montre que pour l'analyse quantitative du fluor ou du chlore, le rapport signal sur bruit le plus favorable necessite les plus faibles energies. L'etude spatiale du plasma a revele que la distribution des etats excites est, quel que soit la molecule introduite dans la chambre de mesure, identique aux energies d'excitation pres. Ainsi nous avons demontre que l'optimisation sur une raie d'emission suffit pour determiner la fibre la plus sensible et que la distribution des etats excites au sein du plasma est independante de la molecule etudiee. La resolution temporelle fine montre que la duree de vie des etats excites atomiques ne depasse pas 20 s apres la fin de l'impulsion laser ; la raie principale du fluor etant la moins persistante (8 s) et celle du chlore la plus durable (20 s). En optimisant tous les parametres participant a la formation du plasma et a l'analyse de son spectre pour obtenir le rapport du signal sur le bruit le plus important, nous avons montre que nous pouvions mesurer en moins de 10 secondes jusqu'a 24 ppm de cf#4. D'autre part, sans optimisation temporelle, nous avons trouve une limite de detection pour cf#2cl#2 d'environ 80 ppm sur la raie principale du chlore ; ce qui correspond aux valeurs recherchees pour la detection de l'yperite
26
Saloum, Saker. "Diagnostic par spectroscopie d'émission de plasmas RF quasi-thermiques à base d'air dans le domaine 2500-6000 K : application a la pyrolyse de molécules chlorofluorocarbonées (CFCs) et à la calibration d'un dispositif de contrôle en temps réel des concentrations de polluants métalliques dans l'atmosphère." Toulouse 3, 2002. http://www.theses.fr/2002TOU30068.
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Almeziny, Mohammed A. N. "Performance of two different types of inhalers. Influence of flow and spacer on emitted dose and aerodynamic characterisation." Thesis, University of Bradford, 2009. http://hdl.handle.net/10454/4299.
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This thesis is based around examination of three mainstream inhaled drugs
Formoterol, Budesonide and Beclomethasone for treatment of asthma and
COPD.
The areas investigated are these which have been raised in reports and
studies, where there are concern, for drug use and assessment of their use.
In reporting this work the literature study sets out a brief summary of the
background and anatomy and physiology of the respiratory system and then
discuses the mechanism of drug deposition in the lung, as well as the
methods of studying deposition and pulmonary delivery devices. This section
includes the basis of asthma and COPD and its treatment. In addition, a short
section is presented on the role of the pharmacist in improving asthma and
COPD patient¿s care.
Therefore the thesis is divided into 3 parts based around formoterol,
budesonide and beclomethasone.
In the first case the research determines the in-vitro performance of
formoterol and budesonide in combination therapy. In the initial stage a new
rapid, robust and sensitive HPLC method was developed and validated for
the simultaneous assay of formoterol and the two epimers of budesonide
which are pharmacologically active.
In the second section, the purpose was to evaluate the aerodynamic
characteristics for a combination of formoterol and the two epimers of
budesonide at inhalation flow rates of 28.3 and 60 L/min. The aerodynamic
characteristics of the emitted dose were measured by an Anderson cascade
impactor (ACI) and the next generation cascade impactor (NGI). In all
aerodynamic characterisations, the differences between flow rates 28.3 and
60 were statistically significant in formoterol, budesonide R and budesonide
S, while the differences between ACI and NGI at 60 were not statistically
significant.
Spacers are commonly used especially for paediatric and elderly patients.
However, there is considerable discussion about their use and operation. In
addition, the introduction of the HFAs propellants has led to many changes in
the drug formulation characteristics. The purpose of the last section is to
examine t h e performance of different types of spacers with different
beclomethasone pMDIs. Also, it was to examine the hypothesis of whether
the result of a specific spacer with a given drug/ brand name can be
extrapolated to other pMDIs or brand names for the same drug.
The results show that there are different effects on aerodynamic
characterisation and there are significant differences in the amount of drug
available for inhalation when different spacers are used as inhalation aids.
Thus, the study shows that the result from experiments with a combination of
a spacer and a device cannot be extrapolated to other combination.
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Almeziny, Mohammed Abdullah N. "Performance of two different types of inhalers : influence of flow and spacer on emitted dose and aerodynamic characterisation." Thesis, University of Bradford, 2009. http://hdl.handle.net/10454/4299.
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This thesis is based around examination of three mainstream inhaled drugs Formoterol, Budesonide and Beclomethasone for treatment of asthma and COPD. The areas investigated are these which have been raised in reports and studies, where there are concern, for drug use and assessment of their use. In reporting this work the literature study sets out a brief summary of the background and anatomy and physiology of the respiratory system and then discuses the mechanism of drug deposition in the lung, as well as the methods of studying deposition and pulmonary delivery devices. This section includes the basis of asthma and COPD and its treatment. In addition, a short section is presented on the role of the pharmacist in improving asthma and COPD patient's care. Therefore the thesis is divided into 3 parts based around formoterol, budesonide and beclomethasone. In the first case the research determines the in-vitro performance of formoterol and budesonide in combination therapy. In the initial stage a new rapid, robust and sensitive HPLC method was developed and validated for the simultaneous assay of formoterol and the two epimers of budesonide which are pharmacologically active. In the second section, the purpose was to evaluate the aerodynamic characteristics for a combination of formoterol and the two epimers of budesonide at inhalation flow rates of 28.3 and 60 L/min. The aerodynamic characteristics of the emitted dose were measured by an Anderson cascade impactor (ACI) and the next generation cascade impactor (NGI). In all aerodynamic characterisations, the differences between flow rates 28.3 and 60 were statistically significant in formoterol, budesonide R and budesonide S, while the differences between ACI and NGI at 60 were not statistically significant. Spacers are commonly used especially for paediatric and elderly patients. However, there is considerable discussion about their use and operation. In addition, the introduction of the HFAs propellants has led to many changes in the drug formulation characteristics. The purpose of the last section is to examine t h e performance of different types of spacers with different beclomethasone pMDIs. Also, it was to examine the hypothesis of whether the result of a specific spacer with a given drug/ brand name can be extrapolated to other pMDIs or brand names for the same drug. The results show that there are different effects on aerodynamic characterisation and there are significant differences in the amount of drug available for inhalation when different spacers are used as inhalation aids. Thus, the study shows that the result from experiments with a combination of a spacer and a device cannot be extrapolated to other combination.
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Teng, Ming-Kai, and 鄧明凱. "Comprehensive two-dimensional gas chromatography (GCxGC) for atmospheric chlorofluorocarbons." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/90513370881690109656.
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碩士國立中央大學
化學研究所
98
Abstract Comprehensive two-dimensional chromatography (GCxGC) opened a new era in improving separation resolution for very complex samples. It uses two columns of different polarity to provide orthogonal separation on a 2-D surface, which considerably increases the peak capacity and hence resolution compared to conventional 1-D chromatography. A typical commercial GCxGC system often uses a cryogenic modulator whose cost is high, and the consumption of cryogen creates additional financial burden. In contrast, many studies focused on developing valve-based types of modulators, which are simple in design and construction. Moreover, cryogen is not required. In our study we used a Deans’ switch to construct the modulator for GCxGC. When combined with a self-constructed thermal desorption unit, this system was able to analyze atmospheric chlorofluorocarbons (CFCs) at pptv level. The volatile sample peaks eluted from the first column (DB-1 60 m) were sliced into sample pulses by the Deans’ switch and sent to the second column (PLOT 0.2 m) for the second dimensional separation. For optimal GCxGC separation of CFCs the modulation pulse and period were set at 0.2 s and 3 s, respectively.By varying the sample size of a pressurized air sample, the linearity of the method was better than 0.990. The precision at atmospheric concentrations was better than 4.74% (RSD). The Deans’ switch-GCxGC method was further tested by continuous measuring outdoor ambient air, and compared the atmospheric variability of CCl2F2 (CFC-12) and CClF2CCl2F (CFC-113) with that from the corresponding 1D GC results. The variability of CFC-12 and CFC-113 denoted by RSD was 3.85% and 3.49%, respectively, for GCxGC versus 2.63% and 3.34%, respectively, for 1D GC. The comparable results suggest that our Deans’ switch-GCxGC method is sufficiently robust to analyze atmospheric CFCs.
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Hwang, Hsing Chih, and 黃行志. "Distribution and Modeling of Chlorofluorocarbons in the Northwestern Pacific Ocean." Thesis, 2002. http://ndltd.ncl.edu.tw/handle/66044979424205417020.
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碩士國立中山大學
海洋地質及化學研究所
90
Because CFC-11 and CFC-12 are extremely stable and purely anthropogenic and the CFCs enter the ocean through air-sea exchange at the sea surface, they serve as good tracers for studying the oceans. Since CFCs and tritium share similar characteristics such as their anthropogenic production, inertness to biological activities, a tritium box model applied to the North Atlantic Ocean by J. L. Sarmiento in 1983 is used to study the distribution of CFCs in the Northwest Pacific. This thesis attempts to use this model to calculate the past concentrations of CFCs in the atmosphere assuming equilibrium distribution between the surface ocean waters and the atmosphere in the source region of the oceans. The results may allow us to check the history of CFCs in the atmosphere. The data used in this thesis are those reported by NOAA from three cruises: CO2-87 and CGC92 along 165oE and CO2-88 along 170oW, all from 40o to 10oN. This latitude range avoids the complex gyres and the sea-ice which may limit the air-sea exchange in the North, and also avoids the upwelling in the equatorial region. The outcrop of the 26.0 sq water is located at longitude about 52o-53oN along 165oE, but is located at about 40oN along 170oW. The outcrop will move southward in winter. The vertical distribution pattern of CFCs is similar to that of oxygen. Concentrations of CFCs in ocean water increase as potential temperature and salinity decrease. High latitudes of low temperature and salinity have high CFC solubility and high air-sea exchange rates, and are presumably the major areas for input of CFCs into the seawater. As the CFCs in the air increase over the years the concentrations of CFCs in the surface ocean water also increase but decrease with water depth. The solubility, F, of CFCs is a function of both temperature and salinity, but temperature prevails. The F values for CFC-11 and CFC-12 from 10o to 50oN along 165oE are 5.86-16.0 and 1.70-4.15 mmole/kg/ atm, respectively. The values along 170oW are, respectively, 6.60-22.2 and 1.89-5.55 mmole/kg/atm. The solubility of CFC-11 is about four times as large as that of CFC-12. The solubility of CFCs along 170oW is about 1.4 times along 165oE because of temperature and salinity differences. The exchange rate in the time scale for =1 year ranges 0.85-1.3 yr-1, CFC-11 has a mean of 0.99 yr-1, CFC-12 has a mean of about 1.04 yr-1. Along the isopycnal surface of sq=26.0, the highest exchange rate between two boxes is 2.34 yr-1, the lowest 0.06 yr-1. Based on the calculated concentrations of CFCs in the surface seawater from the atmospheric value in the past, apparent ages of the Mode Waters are similar for both CFC-11 and CFC-12. The apparent age along 165oE at 10oN is about 17 years on the defined isocypnal surface, and it is about 15 years along 170oW at 10oN. The spreading rate of CFCs in the Northwest Pacific is thus about 172-221 km/yr. During the 17 years, the annual increase in influx to the seawater is about 0.12 pM/kg/yr for CFC-11, and about 0.059 pM/kg/yr for CFC-12. The error in calculating atmosphere CFCs in the past is about 11 % for CFC-11, and 6 % for CFC-12.
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Chern, Jong-Yuan, and 陳中元. "Kinetics Study of Hydrogenolysis of Chlorofluorocarbons over La1-xSrxNiO3(x=0.3,0.5) Catalysts." Thesis, 1996. http://ndltd.ncl.edu.tw/handle/61559524667299764289.
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Lin, Jenq Hwang, and 林正煌. "Study of the Hydrogenolysis of Chlorofluorocarbons over Nickel- Containing Mixed Metal Oxide Catalysts." Thesis, 1995. http://ndltd.ncl.edu.tw/handle/46529446714135971846.
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碩士逢甲大學
土木及水利工程研究所
83
This thesis is for the purpose of studying the hydrogeno- lysis of the chlorofluorocarbons over some nickle-containing mixed oxide catalysts. Their structures and micrographs were characterized by XRD and SEM. The result indicates that substitution of La by Sr affects activity due to the La2NiO4-, NiO-, and SrO2-phases in the catalytic structure, while the amount of each phases increases with increasing x. But, the activity does not increase with increasing amounts of these phases; the highest activity occur- ring at x=0.3 or 0.5. It is believed that the catalysts are poisoned by the chlo- rine and/ or fluorine, which are the products of the hydrogeno- lysis of CFC-12 or CFC-113. The behavior of the Cl- and/or F-poisoned catalysts can be well explained by the aids of ESCA and SEM/WDS spectra. It is found that the behavior of these catalysts depend on the amount of chemisorbed chlorine and/or fluorine. When the B site (Ni cation) is occupied by chlorine and/or fluorine the catalyst is deactivated and no further reaction occurs. However , when chlorine and/or fluorine atoms are adsorbed on the A sites (La or Sr cation), the activity will not be affected because the A cation are in general catalystic- ally inactive. For LaNiO3, La0.7Sr0.3NiO3, and La0.5Sr0.5NiO3 catalysts, the chlorine and fluorine are adsorbed on the B cation at low temperature, but desorbed at the temperature over 260℃ then the activity increasing quickly. The activity of La0.3Sr0.7NiO3 and SrNiO3 catalysts is lower as chlorine and fluorine atoms adsorbed on the B cation until reaction tempe- rature over 400℃. The mechanisms of the hydrogenolysis of CFC-12 and CFC-113 over these nickle-containing mixed oxide catalysts are proposed by the aids of GC/MS analysis for the products.
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Ohi, James M. "Science and global environmental pollution issues a case study of stratospheric ozone depletion by chlorofluorocarbons /." 1985. http://catalog.hathitrust.org/api/volumes/oclc/30791600.html.
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Alcock, Deborah. "The realization of an issue on the government decision agenda : the case of chlorofluorocarbons and ozone layer depletion." Thesis, 1990. http://spectrum.library.concordia.ca/5285/1/ML56039.pdf.
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Žujová, Magdaléna. "Ochrana ozónové vrstvy Země z pohledu práva." Master's thesis, 2015. http://www.nusl.cz/ntk/nusl-335371.
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107 Summary The Ozone layer of the Earth located in the stratosphere in an altitude of 20 to 50 kilometres is the important part of the gases surrounding the planet Earth. Its purpose is to absorb UV radiation that otherwise very negatively affects life on the Earth. During the twentieth century, this ability was weakened by the emission of substances proven much later to be very dangerous in this way. Until 1987, by various chemical reactions, in particular of chlorine atoms, the ozone hole has been formed over the South Pole of the Earth, not fully healed yet. In 1985, risk to human life led using the precautionary principle to the adoption of the Vienna Convention and subsequently of its implementing protocol including specific obligations especially the control measures of the production and consumption of ozone depleting substances and of the trade with them in 1987. The protocol was later modified by amendments and adjustments. This diploma thesis describes these acts with respect to their evolution and actual state of knowledge. At European level, it shows the evolution of the European environmental law in focus on the protection of the ozone layer and on the process of incorporation of international instruments in this area of environmental law. It describes these European acts and compares the...
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柴田, 英治, 康浩 竹内, and 学. 市原. "フロン代替有機溶剤の生物学的モニタリング." 2000. http://hdl.handle.net/2237/13092.
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