Greater fuel efficiency is potentially preferable to reducing NOx emissions for aviation’s climate impacts

Aviation emissions of nitrogen oxides (NOx) alter the composition of the atmosphere, perturbing the greenhouse gases ozone and methane, resulting in positive and negative radiative forcing effects, respectively. In 1981, the International Civil Aviation Organization adopted a first certification standard for the regulation of aircraft engine NOx emissions with subsequent increases in stringency in 1992, 1998, 2004 and 2010 to offset the growth of the environmental impact of air transport, the main motivation being to improve local air quality with the assumed co-benefit of reducing NOx emissions at altitude and therefore their climate impacts. Increased stringency is an ongoing topic of discussion and more stringent standards are usually associated with their beneficial environmental impact. Here we show that this is not necessarily the right direction with respect to reducing the climate impacts of aviation (as opposed to local air quality impacts) because of the tradeoff effects between reducing NOx emissions and increased fuel usage, along with a revised understanding of the radiative forcing effects of methane. Moreover, the predicted lower surface air pollution levels in the future will be beneficial for reducing the climate impact of aviation NOx emissions. Thus, further efforts leading to greater fuel efficiency, and therefore lower CO2 emissions, may be preferable to reducing NOx emissions in terms of aviation’s climate impacts

Technology Review of Sustainable Aircraft Design

Since the beginning of the aviation industry, fossil fuel is being used as the only source of fuel to power airplanes. Each year the popularity of aviation industry among the passengers is increasing dramatically because of its short journey time. Therefore, the demand of fossil fuel is also increasing to support the additional need. However, the stock of fossil fuel is reducing and will all be consumed within a couple of decades. In addition to this, the increment of greenhouse gas has become another issue, which should be dealt with urgently in order to not contribute to global warming. Because of these upcoming problems, another source of fuel and a significant development in aircraft design are a must for the future of aviation industry. Some new sources of fuels are being tested as alternative fuels. Solar power, biofuels, and hydrogen fuel are some of them. New techniques for aircraft design have also been developed within the last couple of years. To make these new ideas available, all the aircraft manufacturing companies and engineers should work collectively

The DNA sequence and biological annotation of human chromosome 1.

The reference sequence for each human chromosome provides the framework for understanding genome function, variation and evolution. Here we report the finished sequence and biological annotation of human chromosome 1. Chromosome 1 is gene-dense, with 3,141 genes and 991 pseudogenes, and many coding sequences overlap. Rearrangements and mutations of chromosome 1 are prevalent in cancer and many other diseases. Patterns of sequence variation reveal signals of recent selection in specific genes that may contribute to human fitness, and also in regions where no function is evident. Fine-scale recombination occurs in hotspots of varying intensity along the sequence, and is enriched near genes. These and other studies of human biology and disease encoded within chromosome 1 are made possible with the highly accurate annotated sequence, as part of the completed set of chromosome sequences that comprise the reference human genome