Discontinuous Galerkin finite element approximation of quasilinear elliptic boundary value problems I: The scalar case

We develop a one--parameter family of hp-version discontinuous Galerkin finite element methods for the numerical solution of quasilinear elliptic equations in divergence-form in a bounded Lipschitz domain. Using Brouwer's Fixed Point Theorem, we show existence and uniqueness of the solution. In addition, we derive an error bound in a broken energy norm which is optimal in h and mildly suboptimal in p

Environmental Effects of Stratospheric Ozone Depletion, UV Radiation, and interactions with Climate Change: 2022 Assessment Report

The Montreal Protocol on Substances that Deplete the Ozone Layer was established 35 years ago following the 1985 Vienna Convention for protection of the environment and human health against excessive amounts of harmful ultraviolet-B (UV-B, 280-315 nm) radiation reaching the Earth’s surface due to a reduced UV-B-absorbing ozone layer. The Montreal Protocol, ratified globally by all 198 Parties (countries), controls ca 100 ozone-depleting substances (ODS). These substances have been used in many applications, such as in refrigerants, air conditioners, aerosol propellants, fumigants against pests, fire extinguishers, and foam materials. The Montreal Protocol has phased out nearly 99% of ODS, including ODS with high global warming potentials such as chlorofluorocarbons (CFC), thus serving a dual purpose. However, some of the replacements for ODS also have high global warming potentials, for example, the hydrofluorocarbons (HFCs). Several of these replacements have been added to the substances controlled by the Montreal Protocol. The HFCs are now being phased down under the Kigali Amendment. As of December 2022, 145 countries have signed the Kigali Amendment, exemplifying key additional outcomes of the Montreal Protocol, namely, that of also curbing climate warming and stimulating innovations to increase energy efficiency of cooling equipment used industrially as well as domestically. As the concentrations of ODS decline in the upper atmosphere, the stratospheric ozone layer is projected to recover to pre-1980 levels by the middle of the 21st century, assuming full compliance with the control measures of the Montreal Protocol. However, in the coming decades, the ozone layer will be increasingly influenced by emissions of greenhouse gases and ensuing global warming. These trends are highly likely to modify the amount of UV radiation reaching the Earth\u27s surface with implications for the effects on ecosystems and human health. Against this background, four Panels of experts were established in 1988 to support and advise the Parties to the Montreal Protocol with up-to-date information to facilitate decisions for protecting the stratospheric ozone layer. In 1990 the four Panels were consolidated into three, the Scientific Assessment Panel, the Environmental Effects Assessment Panel, and the Technology and Economic Assessment Panel. Every four years, each of the Panels provides their Quadrennial Assessments as well as a Synthesis Report that summarises the key findings of all the Panels. In the in-between years leading up to the quadrennial, the Panels continue to inform the Parties to the Montreal Protocol of new scientific information

Ozone depletion, ultraviolet radiation, climate change and prospects for a sustainable future

Changes in stratospheric ozone and climate over the past 40-plus years have altered the solar ultraviolet (UV) radiation conditions at the Earth's surface. Ozone depletion has also contributed to climate change across the Southern Hemisphere. These changes are interacting in complex ways to affect human health, food and water security, and ecosystem services. Many adverse effects of high UV exposure have been avoided thanks to the Montreal Protocol with its Amendments and Adjustments, which have effectively controlled the production and use of ozone-depleting substances. This international treaty has also played an important role in mitigating climate change. Climate change is modifying UV exposure and affecting how people and ecosystems respond to UV; these effects will become more pronounced in the future. The interactions between stratospheric ozone, climate and UV radiation will therefore shift over time; however, the Montreal Protocol will continue to have far-reaching benefits for human well-being and environmental sustainability.Peer reviewe

A posteriori error analysis of mixed finite element approximations to quasi-Newtonian incompressible flows

We develop the a posteriori error analysis of mixed finite element approximations of a general family of steady, viscous, incompressible quasi-Newtonian fluids in a bounded Lipschitz domain; the family includes degenerate models such as the power-law model, as well as non-degenerate ones such as the Carreau model. The unified theoretical framework developed herein yields residual-based a posteriori bounds which measure the error in the approximations of the velocity and the pressure

Effect of Water and Solvent Selection on the SAFA Purification Times for Metallic Nitride Fullerenes

This paper addresses two key parameters in the SAFA purification method for isolating endohedral metallofullerenes. The percent water content in the reactive aminosilica significantly affects the time needed to isolate Sc3N@Ih-C80 metallic nitride fullerene (MNF). The role of solvent selection in the SAFA process is also discussed. The SAFA purification time needed for isolating Sc3N@Ih-C80 metallofullerene is influenced by the identity of the electron donating/accepting group on the aromatic solvent

Environmental Effects and Interactions of Stratospheric Ozone Depletion, UV Radiation, and Climate Change. 2018 Assessment Report

Executive Summary: Thirty-four years ago, an unprecedented thinning of stratospheric ozone was reported over Antarctica.The risk of a consequent increase in exposure to solar UV-B radiation (UV-B; wavelengths 280-315 nm) raised concerns about potentially disastrous effects on human health and the Earth\u27s environment. In response, the international community mobilised and worked together to understand the causes and find a solution to this dramatic change in the Earth\u27s atmosphere. In 1985, the Vienna Convention for the Protection of the Ozone Layer was signed, which provided the framework for the Montreal Protocol on Substances that Deplete the Ozone Layer, signed in 1987. In these international agreements, the United Nations recognised the fundamental importance of stopping and reversing ozone depletion and preventing its damaging effects. The Montreal Protocol, with its subsequent Amendments and Adjustments, was negotiated to control the consumption and production of anthropogenic ozone-depleting substances. The Parties to the Montreal Protocol base their decisions on scientific, environmental, technical, and economic information provided by three Assessment Panels ..