The First International Nitrogen Conference provided an opportunity for researchers and decision-makers to exchange information on environmental pollution by nitrogen compounds on three scales: global, continental/regional and local. The main topics were air, ground water and surface water pollution; emission sources, atmospheric chemistry, deposition processes and effects; disturbance of nitrogen cycles, critical loads and levels; assessments, policy development and evaluation; target groups and abatement techniques; and new approaches leading to an integrated abatement strategy.The peer-reviewed papers from the Conference presented in this volume will provide readers with a comprehensive review of the transport, deposition and impact on ecosystems of nitrogen.

The completion of the initial phase of the U.S. National Acid Precipitation Assessment Program (NAPAP) in 1990 marked the end of the largest environmental research and assessment effort to that time. The resulting series of 27 State of Science and Technology (SOS/T) Reports and the NAPAP Integrated Assessment represent a decade of work by hundreds

Discusses a different approach to addressing environmental problems, aimed at a broad interdisciplinary audience.

Unconventional heavy crude oils are replacing the conventional light crude oils slowly but steadily as a major energy source. Heavy crude oils are cheaper and present an opportunity to the refiners to process them with higher profit margins. However, the unfavourable characteristics of heavy crude oils such as high viscosity, low API gravity, low H/C ratio, chemical complexity with high asphaltenes content, high acidity, high sulfur and increased level of metal and heteroatom impurities impede extraction, pumping, transportation and processing. Very poor mobility of the heavy oils, due to very high viscosities, significantly affects production and transportation. Techniques for viscosity reduction, drag reduction and in-situ upgrading of the crude oil to improve the flow characteristics in pipelines are presented in this book. The heavier and complex molecules of asphaltenes with low H/C ratios present many technological challenges during the refining of the crude oil, such as heavy coking on catalysts. Hydrogen addition and carbon removal are the two approaches used to improve the recovery of value-added products such as gasoline and diesel. In addition, the heavy crude oil needs pre-treatment to remove the high levels of impurities before the crude oil can be refined. This book introduces the major challenges and some of the methods to overcome them.