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(1 - 6 of 6)
- Title
- Examination of observed hydroxyl column abundance behaviors using a mesospheric model.
- Creator
- Liu, Yan, Florida Atlantic University, Burnett, Elizabeth B., Burnett, Clyde R.
- Abstract/Description
-
OH vertical column abundances have been measured since 1977. Based on this long-term data base, the terrestrial OH abundance trends, such as the high-sun (secX = 1) enhancement of the zenith angle dependence, seasonal variations, and diurnal behaviors, have been observed. Current atmospheric models do not predict these features. In this thesis, a one dimensional photochemical model of the mesosphere has been constructed in order to examine the possibility that these observed effects might...
Show moreOH vertical column abundances have been measured since 1977. Based on this long-term data base, the terrestrial OH abundance trends, such as the high-sun (secX = 1) enhancement of the zenith angle dependence, seasonal variations, and diurnal behaviors, have been observed. Current atmospheric models do not predict these features. In this thesis, a one dimensional photochemical model of the mesosphere has been constructed in order to examine the possibility that these observed effects might originate in this region of the atmosphere. Transport effects are not considered. The model result demonstrates that the observed OH behaviors are not caused by known photochemical reactions in the mesosphere.
Show less - Date Issued
- 1990
- PURL
- http://purl.flvc.org/fcla/dt/14579
- Subject Headings
- Atmospheric ozone, Photochemistry
- Format
- Document (PDF)
- Title
- OBSERVATIONS OF ATMOSPHERIC HYDROXYL AND THEIR SIGNIFICANCE TO MIDDLE ATMOSPHERIC PHOTOCHEMISTRY.
- Creator
- MINSCHWANER, KENNETH ROBERT, Florida Atlantic University
- Abstract/Description
-
Observations of the vertical column abundance of atmospheric hydroxyl (OH) have been made using a Pepsios (polyetalon pressure-scanned interferometric optical spectrometer). The measurements were taken at both Fritz Peak, Colorado (40°N) and Boca Raton, Florida (26° N) during the period 1985-86. These are high resolution measurements of the resonance absorption of sunlight by OH in the P1(1) A^2 sigma - x^2 pi (0,0) transition at 3081.66 A. The observations are of relevance to the problem of...
Show moreObservations of the vertical column abundance of atmospheric hydroxyl (OH) have been made using a Pepsios (polyetalon pressure-scanned interferometric optical spectrometer). The measurements were taken at both Fritz Peak, Colorado (40°N) and Boca Raton, Florida (26° N) during the period 1985-86. These are high resolution measurements of the resonance absorption of sunlight by OH in the P1(1) A^2 sigma - x^2 pi (0,0) transition at 3081.66 A. The observations are of relevance to the problem of stratospheric ozone reduction by man-made pollution. Attempts to model the photochemistry of the middle atmosphere and to predict its response to these pollutants depend heavily on an accurate observational data base of many middle atmospheric constituents. This OH data base contributes information which is of critical importance to theories describing middle atmospheric processes. The author's measurements are discussed within the context of the ten-year data base accumulated by Dr. Clyde Burnett. Observed geographic and seasonal regularities, as well as short-period excursions in the OH abundances, have not been fully explained by current photochemical theory.
Show less - Date Issued
- 1987
- PURL
- http://purl.flvc.org/fcla/dt/14357
- Subject Headings
- Atmospheric ozone, Photochemistry
- Format
- Document (PDF)
- Title
- Photodegradation of propiconazole fungicide by ultraviolet radiation.
- Creator
- Martinez, Omar R., Florida Atlantic University, Parkanyi, Cyril
- Abstract/Description
-
The photodegradation of propiconazole (1-{[2-(2,4-dichlorophenyl)-4-propyl-1,3-dioxolan-2-yl]methyl}-1 H-1,2,4-triazole), a systemic fungicide, by ultraviolet radiation has been studied. After 12 hours of continuous irradiation, propiconazole undergoes degradation in aqueous solution. The process requires the presence of oxygen and continuous agitation. Similarly, propiconazole undergoes degradation in organic solvents as well (methanol, hexane)., Four photoproducts were detected and...
Show moreThe photodegradation of propiconazole (1-{[2-(2,4-dichlorophenyl)-4-propyl-1,3-dioxolan-2-yl]methyl}-1 H-1,2,4-triazole), a systemic fungicide, by ultraviolet radiation has been studied. After 12 hours of continuous irradiation, propiconazole undergoes degradation in aqueous solution. The process requires the presence of oxygen and continuous agitation. Similarly, propiconazole undergoes degradation in organic solvents as well (methanol, hexane)., Four photoproducts were detected and identified and one of them was isolated. The dioxolan ring is the structure susceptible to the cleavage in the irradiation process.*, *Please refer to dissertation for diagram.
Show less - Date Issued
- 2001
- PURL
- http://purl.flvc.org/fcla/dt/12841
- Subject Headings
- Photochemistry, Fungicides, Ultraviolet radiation
- Format
- Document (PDF)
- Title
- Photodegradation of 2-substituted benzimidazole fungicides by ultraviolet radiation.
- Creator
- Chen, Dong., Florida Atlantic University, Parkanyi, Cyril
- Abstract/Description
-
The photodegradation of benzimidazole-based fungicides: benomyl ({1- [(butylamino) carbonyl)-1H-benzimidazol-2-yl} carbamic acid methyl ester), thiabendazole (2-(4-thiazolyl)-1H-benzimidazole) and fuberidazole (2-(2-furyl)-1H-benzimidazole) by ultraviolet radiation has been studied. Benomyl in an organic solvent (chloroform) undergoes a rapid degradation even without any UV radiation; UV radiation and air agitation will increase the rate of the reaction. The degradation product was found to...
Show moreThe photodegradation of benzimidazole-based fungicides: benomyl ({1- [(butylamino) carbonyl)-1H-benzimidazol-2-yl} carbamic acid methyl ester), thiabendazole (2-(4-thiazolyl)-1H-benzimidazole) and fuberidazole (2-(2-furyl)-1H-benzimidazole) by ultraviolet radiation has been studied. Benomyl in an organic solvent (chloroform) undergoes a rapid degradation even without any UV radiation; UV radiation and air agitation will increase the rate of the reaction. The degradation product was found to be methyl 2-benzimidazolecarbamate (MBC) in all cases. The degradation of thiabendazole and fuberidazole in methanol was also studied under different conditions but degradation was observed only under UV radiation and in the presence of oxygen, 7-8 Photodegradation products were found in the mixture after irradiation of thiabendazole but only 2 of them were separated from the mixture and identified. Benzimidazole-2-carboxamide and dimethyl oxalate were two of the final photodegradation products of thiabendazole in methanol. It is clear that the thiazole ring is the most vulnerable part of the molecule and suffers ring cleavage. No photodegradation products of fuberidazole were identified so far.
Show less - Date Issued
- 1994
- PURL
- http://purl.flvc.org/fcla/dt/15061
- Subject Headings
- Benomyl, Ultraviolet radiation, Photochemistry, Fungicides
- Format
- Document (PDF)
- Title
- Photodegradation of bromacil and terbacil by ultraviolet radiation.
- Creator
- Johnson, Hannah Kalyani, Florida Atlantic University, Parkanyi, Cyril, Charles E. Schmidt College of Science, Department of Chemistry and Biochemistry
- Abstract/Description
-
The photodegradation of bromacil (5-bromo-3-sec-butyl-6-methyluracil) and terbacil (5-chloro-3-tert-butyl-6-methyluracil) by ultraviolet radiation has been investigated. Irradiation of aerated aqueous solutions of the title compounds (25 ppm), led to fast degradation of both. The reactions were found to follow first order kinetics with rate constants 5.77x10^-1 hr^-1 in the case of bromacil and 8.45x10^-2 hr^-1 in the case of terbacil. Degradation in ethanol and cyclohexane was also studied,...
Show moreThe photodegradation of bromacil (5-bromo-3-sec-butyl-6-methyluracil) and terbacil (5-chloro-3-tert-butyl-6-methyluracil) by ultraviolet radiation has been investigated. Irradiation of aerated aqueous solutions of the title compounds (25 ppm), led to fast degradation of both. The reactions were found to follow first order kinetics with rate constants 5.77x10^-1 hr^-1 in the case of bromacil and 8.45x10^-2 hr^-1 in the case of terbacil. Degradation in ethanol and cyclohexane was also studied, but the solutions were not analyzed for photoproducts. The photoreaction mixture of both the herbicides in water showed four peaks on GC, indicating four photoproducts. Loss of halogens from the heterocyclic ring has been observed as shown by the presence of Br- in the case of bromacil and Cl- in the case of terbacil in the photoreaction solution. 6-Methyluracil which was isolated from the aqueous fraction of the photoreaction mixture was the common photoproduct from both bromacil and terbacil. From the organic fractions 3-sec-butyl-5-acetyl-5-hydroxyhydantoin was identified in the case of bromacil and 3-tert-butyl-5-acetyl-5-hydroxyhydantoin in the case of terbacil. The other two photoproducts were left unidentified.
Show less - Date Issued
- 1993
- PURL
- http://purl.flvc.org/fcla/dt/14929
- Subject Headings
- Ultraviolet radiation, Photochemistry--Deterioration, Herbicides, Uracil
- Format
- Document (PDF)
- Title
- Synthesis and characterization of ruthenium-containing polymers derived from diamine-containing dyes.
- Creator
- Murphy, Amanda Taylor, Florida Atlantic University, Carraher, Charles E.
- Abstract/Description
-
Ruthenium-containing polymers derived from cis-dichloro-bis(2-2'-bipyridine) ruthenium and selected diamine-containing dyes have been synthesized. These polymeric products were characterized using FTIR, UV-Vis spectroscopy, light scattering photometry, and mass spectral analysis. Thermal degradation studies of these products are also presented.
- Date Issued
- 1996
- PURL
- http://purl.flvc.org/fcla/dt/15244
- Subject Headings
- Polymers, Ruthenium compounds, Photochemistry, Dyes and dyeing--Chemistry, Solar energy
- Format
- Document (PDF)
