The purpose of this study was to investigate preservice science teachers&rsquo / mental models about the role and distribution of ozone layer and ozone layer depletion regarding their ontological orientation. This study was conducted with twenty four preservice science teachers who were enrolled in Elementary Science Education Program of Education Faculty of one public university located in Central Anatolia. From each grade level six preservice science teachers were selected / two from low achiever, two from middle achiever and two from high achiever. Moreover, in the study, data were collected by using semi structured interview and interview consists of eleven questions and with five questions having multiple parts. Interview recordings were transcribed and analyzed qualitatively. In the following steps of the analysis, researcher proceeded with the already formed and described codes in an easygoing way. The results revealed that preservice science teachers&rsquo / responses were mostly seen as skin cancer and sunburn as harmful effects of ultraviolet rays and preservice science teachers&rsquo / responses were mostly seen as activation vitamin D and photosynthesis of plants as beneficial effects of Sun&rsquo / s rays. Half of preservice science teachers thought that ozone layer exists in the atmosphere. Moreover, preservice science teachers&rsquo / responses were mostly seen as perfume, deodorant, car, and spray as harmful materials to ozone layer. Chlorofluorocarbon, carbon monoxide, and carbon-dioxide were the most seen responses as harmful chemicals to ozone layer. Similar misconceptions were identified when compared with past studies. Also, different misconceptions were found in the study. Ten distinct models were formed regarding role and distribution of ozone layer and five distinct models were formed regarding ozone layer depletion. Moreover, absorbing and reflecting surface was mostly seen ontological belief regarding role and distribution of ozone layer. Hole was mostly seen ontological belief regarding ozone layer depletion. Generally, achievement and grade level did not make difference among preservice science teachers forming which type of mental models and having ontological beliefs.

Measurements by the TOMS instrument aboard the Nimbus 7 satellite, of total column ozone over polar regions have been studied to determine the effects of solar induced natural ozone modulation. Two different analysis methods were employed to ascertain short term (days to months) and long term (months to years) solar influences on polar ozone. Bursts of intense solar activity can result in solar proton events (SPE's). The high energy protons, originating in solar flares, produce secondary electrons which can generate large concentrations of odd nitrogen in the middle atmosphere. These reactive species can catalytically destroy ozone. Three case studies are presented in an attempt to quantify the effect of SPE's on ozone mass over a latitude region 90 to 70°. In order to monitor the ozone response following a SPE over both hemispheres simultaneously, the SPE must occur during the equinox period when both poles are irradiated. Fortuitously, a SPE was recorded in March 1989, the analysis of which forms a case study in this thesis. Ozone depletions of 7.4 x 10 to the power of 9 kg for the south polar cap and 8.0 x 10 to the power of 9 kg for the north polar cap indicate the degree of symmetry for this event. Longer term effects of solar variability are investigated by Fourier techniques. A Fourier transform of eleven years of total ozone mass values, over the region 90 to 70° S, was performed. Inspection of the Fourier spectrum reveals peaks associated with solar cycle, annual and semi-annual oscillations, that may be attributed directly to solar variation. Other peaks, corresponding to QBO and ENSO periodicities, may be ascribed to indirect solar influences i.e. thermally driven dynamics. Finally, a comparison between the phase of the solar cycle peak in this spectrum with that in a spectrum of daily values of solar radio flux, reveals that the austral polar ozone solar cycle periodicity lags solar forcing by 2.8 years. Portions of chapters have been reported at the 1990 South African Institute of Physics Annual Conference, University of Port Elizabeth, South Africa and as a poster at the 1992 Quadrennial Ozone Symposium, Charlottesville, United States of America, 4-13 June 1992. In addition, various parts of this work has been submitted for publication, viz: Stephenson, J. A. E. and M. W. J. Scourfield, Importance of energetic solar protons in ozone depletion, Nature, 352, 137: 1991. / Thesis (Ph.D.)-University of Natal, Durban, 1994.

Thesis Ph.D. ((Applied Mathematics)) -- University of Limpopo, 2022 / The world is under threat from the devastating effects of the continued depletion of the Ozone layer. Increased global warming is causing catastrophic ecological damage and imbalance due to accelerated melting of glaciers, rampant runaway veld res, widespread floods and other extreme events. The delegates to the Cop26 Climate Change Summit were reminded that the continued burning of fossil fuels is releasing carbon into the atmosphere at an unprecedented pace and scale and that the world is already in trouble. Complete substitution of fossil fuels with clean energy sources is the only solution through which the world can be saved from the deleterious effects of global warming. However, total dependence on renewable energy sources can only be possible through novel technology that enables efficient energy utilization and conservation. For instance, the evolution of advanced techniques in manufacturing processes has led to the reduction in the size of various industrial and engineering designs that consume reduced amounts of energy. Efficient energy utilization in thermo-fluid flow systems can be achieved through entropy generation minimization. Entropy is a thermodynamic quantity that represents the unavailability of a system's thermal energy for conversion into mechanical work. In this study, thermodynamic analysis of reactive variable properties third-grade fluid flow in channels with varied geometries and subjected to different physical effects was investigated with the second law of thermodynamics as the area of focus. Entropy generation and inherent irreversibility analysis were the main focus of the study where the sensitivities of these quantities to the embedded parameters were numerically and graphically described and analysed. The semi-analytic Adomian decomposition method, the semi-implicit fi nite difference scheme and the spectral quasilinearisation method were employed to solve the nonlinear differential equations modelling the flow systems. The results reveal that the effects of the parameters on flow velocity, fluid temperature, entropy generation and inherent irreversibility cannot be neglected. In particular, conditions for entropy generation minimization were successfully established and documented. / University of Limpopo

Surface deposition is an important sink for tropospheric ozone. The rate of ozone deposition may be measured by measuring the downward flux of ozone in the atmospheric surface-layer. This thesis presents eddy correlation measurements of ozone fluxes, taken on eight days in August, 1994, at a grassland site located in the Lower Fraser Valley of British Columbia. Surface resistances to ozone deposition were calculated from the flux measurements. Much of the variability in measured surface resistances was found to be attributable to variations in ambient light levels and in the degree of moisture stress at the site. Measurements of surface resistance from this site agreed quite well with other measurements of ozone deposition to grassland surfaces. Measured surface resistances were compared to surface resistances calculated using the Wesely (1989) parameterization (W89) for surface resistance. W89 underestimated surface resistance, particularly in the mid afternoon and early evening. This was attributed to the model's neglect of the effects of water stress on stomatal resistance, as well as to a low value for resistance to ground surface deposition in the model. The eddy correlation fluxes were compared to ozone fluxes derived using an assumption of cospectral similarity between ozone and heat flux and to ozone fluxes measured using the variance method and the gradient method. The cospectral similarity method worked well and allowed a considerable relaxation of the sampling speed requirements of the eddy correlation method. The variance method produced biased flux measurements due to high frequency noise from the ozone sensor. Flux measurements using the gradient method had a great deal of scatter, due to inaccuracies in the measurement of gradients.

Surface deposition is an important sink for tropospheric ozone. The rate of ozone deposition may be measured by measuring the downward flux of ozone in the atmospheric surface-layer. This thesis presents eddy correlation measurements of ozone fluxes, taken on eight days in August, 1994, at a grassland site located in the Lower Fraser Valley of British Columbia. Surface resistances to ozone deposition were calculated from the flux measurements. Much of the variability in measured surface resistances was found to be attributable to variations in ambient light levels and in the degree of moisture stress at the site. Measurements of surface resistance from this site agreed quite well with other measurements of ozone deposition to grassland surfaces. Measured surface resistances were compared to surface resistances calculated using the Wesely (1989) parameterization (W89) for surface resistance. W89 underestimated surface resistance, particularly in the mid afternoon and early evening. This was attributed to the model's neglect of the effects of water stress on stomatal resistance, as well as to a low value for resistance to ground surface deposition in the model. The eddy correlation fluxes were compared to ozone fluxes derived using an assumption of cospectral similarity between ozone and heat flux and to ozone fluxes measured using the variance method and the gradient method. The cospectral similarity method worked well and allowed a considerable relaxation of the sampling speed requirements of the eddy correlation method. The variance method produced biased flux measurements due to high frequency noise from the ozone sensor. Flux measurements using the gradient method had a great deal of scatter, due to inaccuracies in the measurement of gradients. / Arts, Faculty of / Geography, Department of / Graduate

Thesis (M. Sc. (Statistics)) -- University of Limpopo, 2021 / The effects of ozone depletion on climate change has, in recent years, become a reality, impacting on changes in rainfall patterns and severity of extreme floods or extreme droughts. The majority of people across the entire African continent live in semi-arid and drought-prone areas. Extreme droughts are prevalent in Somalia and eastern Africa, while life-threatening floods are common in Mozambique and some parts of other SADC (Southern African Development Community) countries. Research has cautioned that climate change in South Africa might lead to increased temperatures and reduced amounts of rainfall, thereby altering their timing and putting more pressure on the country’s scarce water resources, with implications for agriculture, employment and food security. The average annual rainfall for South Africa is about 464mm, falling far below the average annual global rainfall of 860mm. The Limpopo Province, which is one of the nine provinces in South Africa, and of interest to this study, is predominantly agrarian, basically relying on availability of water, with rainfall being the major source for water supply. It is, therefore, pertinent that the rainfall pattern in the province be monitored effectively to ascertain the rainy period for farming activities and other uses. Modelling and forecasting rainfall have been studied for a long time worldwide. However, from time to time, researchers are always looking for new models that can predict rainfall more accurately in the midst of climate change and capture the underlying dynamics such as seasonality and the trend, attributed to rainfall. This study employed Exponetial Smoothing (ETS) State Space and Seasonal Autoregressive Integrated Moving Average (SARIMA) models and compared their forecasting ability using root mean square error (RMSE). Both models were used to capture the sporadic behaviour of rainfall. These two models have been widely applied to climatic data by many scholars and adjudged to perform creditably well. In an attempt to find a suitable prediction model for monthly rainfall patterns in Limpopo Province, data ranging from January 1900 to December 2015, for seven weather stations: Macuville Agriculture, Mara Agriculture, Marnits, Groendraal, Letaba, Pietersburg Hospital and Nebo, were analysed. The results showed that the two models were adequate in predicting rainfall patterns for the different stations in the Limpopo Province. / National Research Foundation (NRF)

Methyl halides are trace gases with both natural and anthropogenic origins. Once generated, these gases transport chlorine and bromine into the stratosphere, where they play an important role in ozone depleting catalytic cycles. The Florida Everglades is one location where methyl halide emissions have been proposed to be elevated due to high primary production and ionic halogens. This region also provides a unique study environment due to salt water intrusions, which occur during storm or low marsh water level-high tide events. The purpose of this research was twofold. First, quantification of methyl chloride (CH3Cl) and methyl bromide (CH3Br) production from periphyton mats on a temporal scale was needed. Secondly, to determine how varying concentrations of salinity affect CH3Cl and CH3Br production originating from calcareous periphyton mats within the Everglades. Periphyton was exposed to continuous 12 hour dark/light cycles in varying concentrations of salt water (0, 0.1, 1, 5, and 10 parts per thousand). All water samples were analyzed to determine the production rate of CH3Cl and CH3Br in periphyton samples using a gas chromatograph coupled with an electron capture detector (GC-ECD). Periphyton mats were found to be a producer of CH3Cl in all freshwater (0 parts per thousand) trials and sampling times; however, results from CH3Br analysis found production rates that suggest consumption occurred in the majority of the 0 parts per thousand trials. Production rates for CH3Cl ranged from 0.077 to 0.109 g-1hr-1 after 24 hours, 0.027 to 0.073 pM g-1hr-1 after 48 hours, and 0.034 to 0.047 pM g-1hr-1 after 72 hours. Production rates for the CH3Br freshwater experiments ranged from -0.00025 to 0.00185 pM g-1hr-1 after 24 hours, -0.00022 to -0.00078 pM g-1hr-1 after 48 hours, and -0.00042 to -0.00061 pM g-1hr-1 after 72 hours. This research has also shown that increased salinity does have a significant positive effect on the production of CH3Cl and CH3Br from calcareous periphyton mats, which is important in areas that could be prone to salt water intrusions or rising sea levels due to global climate change.

Les Québécois sont de plus en plus conscients de l’environnement qui les entoure et de l’importance d’en assurer la qualité et la pérennité. Certains phénomènes, tels les changements climatiques, l’accumulation de polluants organiques persistants et l’amincissement de la couche d’ozone, que nous qualifierons de phénomènes environnementaux diffus, sont engendrés par de multiples émetteurs de polluants et ont des effets globaux qui ne peuvent être liés à un événement précis et dont les impacts sont difficiles à identifier et à quantifier pour le moment. En l’absence de preuve quant aux effets qu’auront ces phénomènes diffus sur les citoyens et les difficultés liées à la preuve scientifique du lien causal entre ce dommage et un émetteur de polluant donné, les recours classiques en responsabilité civile et pour troubles de voisinage, prévus aux articles 1457 et 976 C.c.Q., apparaissent inopérants. Nous nous interrogeons donc sur l’existence d’un droit à l’environnement qui conférerait aux citoyens le droit de vivre dans un environnement sain et leur permettrait ainsi de réclamer que cesse toute atteinte environnementale engendrée par ces phénomènes, même si elle n’a pas d’effet directement sur eux. Considérant l’importance de l’efficacité des recours qui pourraient permettre une mise en œuvre de ce droit, nous procéderons à l’analyse de trois sources potentielles d’un droit à l’environnement sous cet angle. À cet effet, nous étudierons les recours constitutionnels et quasi-constitutionnels liés à la Charte canadienne des droits et libertés, à la Charte des droits et libertés de la personne et au recours institutionnel prévu dans la Loi sur la qualité de l’environnement. Considérant l’absence de reconnaissance suffisante d’un droit à l’environnement et de recours efficaces pour en assurer la mise en œuvre, nous proposerons ensuite des pistes de solution afin que puisse être développé un mécanisme permettant une réponse judiciaire aux phénomènes environnementaux diffus. / The quality of the environment has become a growing concern in the recent years for Quebec citizens. Phenomena such as climate change, persistent organic pollutants and the depletion of the ozone layer are caused by several sources, the effects of which cannot be distinguished one from the other and/or linked to a specific event. Furthermore, these phenomena have yet to create damage to Quebec residents in order to create the necessary standing for the introduction of legal proceedings. Also, the scientific uncertainty related to the source of potential damage and to the proof of said damage makes it impossible to legally attack the emitters of the pollutant contributing to this type of environmental phenomena under 1457 C.C.Q. or 976 C.C.Q. We have identified the 3 potential sources of a right to a clean environment which could entitle Quebec citizens to go before the courts in environmental matters, even in the absence of specific damages to their person or property. We have analysed the Canadian Charter of Rights and Freedoms, the Charter of Human Rights and Freedoms and the Environmental Quality Act and looked at the potential right to a clean environment possibly contained therein and the legal actions that could be taken to ensure their respect. Considering the weakness of what our legal system had to propose, we have developed solutions that could be put forward in order to allow the war against climate change and other environmental phenomena of the same nature to become legally actionable.

Les Québécois sont de plus en plus conscients de l’environnement qui les entoure et de l’importance d’en assurer la qualité et la pérennité. Certains phénomènes, tels les changements climatiques, l’accumulation de polluants organiques persistants et l’amincissement de la couche d’ozone, que nous qualifierons de phénomènes environnementaux diffus, sont engendrés par de multiples émetteurs de polluants et ont des effets globaux qui ne peuvent être liés à un événement précis et dont les impacts sont difficiles à identifier et à quantifier pour le moment. En l’absence de preuve quant aux effets qu’auront ces phénomènes diffus sur les citoyens et les difficultés liées à la preuve scientifique du lien causal entre ce dommage et un émetteur de polluant donné, les recours classiques en responsabilité civile et pour troubles de voisinage, prévus aux articles 1457 et 976 C.c.Q., apparaissent inopérants. Nous nous interrogeons donc sur l’existence d’un droit à l’environnement qui conférerait aux citoyens le droit de vivre dans un environnement sain et leur permettrait ainsi de réclamer que cesse toute atteinte environnementale engendrée par ces phénomènes, même si elle n’a pas d’effet directement sur eux. Considérant l’importance de l’efficacité des recours qui pourraient permettre une mise en œuvre de ce droit, nous procéderons à l’analyse de trois sources potentielles d’un droit à l’environnement sous cet angle. À cet effet, nous étudierons les recours constitutionnels et quasi-constitutionnels liés à la Charte canadienne des droits et libertés, à la Charte des droits et libertés de la personne et au recours institutionnel prévu dans la Loi sur la qualité de l’environnement. Considérant l’absence de reconnaissance suffisante d’un droit à l’environnement et de recours efficaces pour en assurer la mise en œuvre, nous proposerons ensuite des pistes de solution afin que puisse être développé un mécanisme permettant une réponse judiciaire aux phénomènes environnementaux diffus. / The quality of the environment has become a growing concern in the recent years for Quebec citizens. Phenomena such as climate change, persistent organic pollutants and the depletion of the ozone layer are caused by several sources, the effects of which cannot be distinguished one from the other and/or linked to a specific event. Furthermore, these phenomena have yet to create damage to Quebec residents in order to create the necessary standing for the introduction of legal proceedings. Also, the scientific uncertainty related to the source of potential damage and to the proof of said damage makes it impossible to legally attack the emitters of the pollutant contributing to this type of environmental phenomena under 1457 C.C.Q. or 976 C.C.Q. We have identified the 3 potential sources of a right to a clean environment which could entitle Quebec citizens to go before the courts in environmental matters, even in the absence of specific damages to their person or property. We have analysed the Canadian Charter of Rights and Freedoms, the Charter of Human Rights and Freedoms and the Environmental Quality Act and looked at the potential right to a clean environment possibly contained therein and the legal actions that could be taken to ensure their respect. Considering the weakness of what our legal system had to propose, we have developed solutions that could be put forward in order to allow the war against climate change and other environmental phenomena of the same nature to become legally actionable.