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.
Results
Showing 1 to 20 of 23 for “"ozone depleting"”.
-
An Investigation of the Distribution of Ozone-depleting Substances in the Upper Troposphere and Lower Stratosphere
… 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 required to resolve uncertainties related to the mechanisms driving the circulation. This work …
-
Impact of two potential policy options on atmospheric chemistry and climate: hydrogen economy and low-GWP alternatives to ozone depleting substances
… of the environment, e.g., attenuation of the ozone layer due to emissions of ozone-depleting substances, climate change due to greenhouse gas emissions, and air pollution due to fossil fuel combustion. This research analyzes the impacts of two potential future policy options, (1) hydrogen …
-
Analysis of aqueous matrices using supercritical fluid extraction in conjunction with chromatographic spectroscopic and mass spectrometric techniques
… legislation now prevents the supply of "ozone depleting" solvents for laboratory purposes. Consequently alternative analytical methods to those which had previously relied upon the use of a range of organic solvents need to be developed. Supercritical fluids exhibit some properties …
-
Natural variability in eastern tropical Pacific nitrous oxide emissions
… oxide (N2O) is a powerful greenhouse gas and ozone depleting substance, but its natural sources remain poorly constrained. Marine emissions are likely much higher than IPCC estimates predict, due to unusually high emissions from the oxygen minimum zones (OMZs) in the eastern tropical Pacific …
-
Globalization and standards : the liberalization of trade and the potential for a regulatory race to the top
… of a race to the top: the Montreal Protocol on Ozone Depleting Substances, dolphin-safe tuna, and fair trade coffee. Many of the concerns of a race to the bottom pertain to process and production methods (PPMs) in global supply chains. One of the themes in this research is the distinction …
-
The Montreal Protocol’s multilateral fund: an environmental and economic success
Although the ozone layer is vital to life on Earth, as a common resource it has been the subject of rational exploitation. With ozone depletion a global (rather than merely regional) problem, measures to address it have necessarily been international efforts. The international treaty that addressed …
-
Solid Waste Biodegradation Enhancements and the Evaluation of Analytical Methods Used to Predict Waste Stability
… waste pose little threat to the environment from ozone depleting gases and groundwater contamination. Limited research has been done to determine the importance of biodegradation enhancement techniques and the analytical methods that are used to characterize waste stability. The purpose of this …
-
Stratospheric ozone in the Earth system
Ozone in the stratosphere protects life on Earth by absorbing much of the ultraviolet solar radiation, as well as being a major source of ozone to the troposphere. A number of factors can influence stratospheric ozone levels and explain past, present and future changes. While there is a large …
-
Nitrous oxide from denitrification: Influence of field management, environmental conditions, and nutrient availability
… (N2O), a potent greenhouse gas and important ozone-depleting substance. To alleviate this environmental issue, there is a need to explore managements and conditions that minimize N2O emissions from agricultural systems. My work combined field, lab, and modeling techniques to decrease …
-
Rheology of molten polystyrene with dissolved gases
… acceptable for replacing previous ozone-depleting hydrochlorocarbon (HFC) refrigerants. A modified pressurized capillary rheometer was employed for the viscosity measurement of molten polystyrene with dissolved gases under elevated pressures and at various temperatures. Experimental …
-
Investigating Tropospheric Hydrogen Peroxide Trends from 1950-2014
… troposphere, is determined by oxidants including ozone (O₃), HOx radicals (OH and HO₂) and hydrogen peroxide (H₂O₂). O₃ is the primary source for HOx radicals, while H₂O₂ is a key sink for HOx radicals that terminates the rapid cycling between OH and HO₂. The concentrations of the HOx radicals and …
-
Attribution of stratospheric ozone change and associated climate impacts
Recognition of stratospheric ozone depletion as a significant global danger sparked the landmark international agreement of the Montreal Protocol to control the production of ozone depleting substances (ODSs). There are now signs of stratospheric ozone recovery, and it is essential to understand …
-
Age of air and the circulation of the stratosphere
… of radiatively important trace gases, such as ozone and water vapor, and other 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 …
-
The Downward Influence of Ozone Depletion in the Arctic Lower Stratosphere
Severe ozone depletion in the polar lower stratosphere has been linked to significant changes in tropospheric circulation patterns in the both hemispheres. Observed Southern Hemisphere circulation changes are easily reproduced in climate models and may be achieved by either increasing ozone …
-
Age of air and the circulation of the stratosphere
… of radiatively-important trace gases, such as ozone and water vapor, and other 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 …
-
Soil solarization and soil additives as alternatives to preplant fumigation in annual plasticulture strawberry production
… for growers until it was classified as an ozone-depleting substance and its use was gradually restricted and legally phased in 2015. Fumigant use has constraints and thus research on other preplant alternatives for soil sterilization of strawberry annual plasticulture production is …
-
Transport and Distribution of the Short-Lived Halocarbons in the Tropical Tropopause Layer in the Pacific Ocean: the Role of Convection
… halocarbons are one of the major groups of the ozone depleting substances as they provide a source for the active halogens which decrease ozone in the atmosphere. The TTL serves as the primary gateway of tropospheric air to enter the stratosphere. The air which enters the stratosphere is …
-
Characterizing biological nitrification inhibition using native Nitrosomonas europaea: mechanism studies and maize cultivar screening
… greenhouse gas (GHG) and is also the leading ozone-depleting substance. Therefore, mitigating nitrification is crucial for reducing the environmental impact of agriculture. Recent research has demonstrated that certain plants release phytochemicals through their roots to suppress …
-
Urea fertilizer placement effects on soil greenhouse gas emissions and corn growth
… atmosphere for at least 100 years. It is also an ozone-depleting gas. Carbon dioxide is problematic due to its abundance in the atmosphere. These GHGs, along with methane, have had a significant impact on climate change. Claypan soils are characterized as having a significantly higher clay content …
-
Long term trends of halogenated trace gases, hydrocarbons, alkyl nitrates and of the oxidative capacity of the atmosphere
Atmospheric trends of a series of ozone depleting substances (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 …
Page 1 of 2