Zeppelins and airplanes went into a commercial competition during the 1920s and 1930s. The Zeppelin was a very costly and high-scale technology which operated with a number of devices less than fingers a hand has. Air...Zeppelins and airplanes went into a commercial competition during the 1920s and 1930s. The Zeppelin was a very costly and high-scale technology which operated with a number of devices less than fingers a hand has. Airplanes, however, were cheap both in investment and operation and improved their cost-effectiveness rapidly during the times. Therefore, it was clear from an economic point of view to develop a fast growing net of commercial airports serving an even fast growing number of passengers. This was self-energizing. Zeppelins, however, focused on one, later two point-to-point services only, justified by a lack of capital and permanent economic losses.展开更多
Ten of thousands of aircraft are expected to retire in the next 20 years.Aircraft manufacturers are gearing up for a new wave of recycling challenges as these aircrafts contain significant higher amount of carbon fibr...Ten of thousands of aircraft are expected to retire in the next 20 years.Aircraft manufacturers are gearing up for a new wave of recycling challenges as these aircrafts contain significant higher amount of carbon fibre reinforced polymer composite,which cannot be recycled by the conventional processes designed for metallic alloys.Aircraft manufacturers have been working with the recycling industry to limit unsustainable dismantling that is harmful to the environment and the potential liability risk of re-entry of un-certified salvaged parts back to the aviation market.An organised recycling network and procedures have already been set up for the conventional metallic alloys and will soon be required to include the composite waste.This paper reports the existing aircraft recycling practice and reviews the key recycling technologies for thermoset composites.Energy consumptions of these technologies are sought from the literature and are reported in this paper.Progress in development of reuse options for the recycled fibre is also included with discussion of their advantages and drawbacks.The challenge of working with the fluffy fibre is considered and the benefit of fibre alignment is highlighted for encouraging a widespread use of the fibre.展开更多
文摘Zeppelins and airplanes went into a commercial competition during the 1920s and 1930s. The Zeppelin was a very costly and high-scale technology which operated with a number of devices less than fingers a hand has. Airplanes, however, were cheap both in investment and operation and improved their cost-effectiveness rapidly during the times. Therefore, it was clear from an economic point of view to develop a fast growing net of commercial airports serving an even fast growing number of passengers. This was self-energizing. Zeppelins, however, focused on one, later two point-to-point services only, justified by a lack of capital and permanent economic losses.
文摘Ten of thousands of aircraft are expected to retire in the next 20 years.Aircraft manufacturers are gearing up for a new wave of recycling challenges as these aircrafts contain significant higher amount of carbon fibre reinforced polymer composite,which cannot be recycled by the conventional processes designed for metallic alloys.Aircraft manufacturers have been working with the recycling industry to limit unsustainable dismantling that is harmful to the environment and the potential liability risk of re-entry of un-certified salvaged parts back to the aviation market.An organised recycling network and procedures have already been set up for the conventional metallic alloys and will soon be required to include the composite waste.This paper reports the existing aircraft recycling practice and reviews the key recycling technologies for thermoset composites.Energy consumptions of these technologies are sought from the literature and are reported in this paper.Progress in development of reuse options for the recycled fibre is also included with discussion of their advantages and drawbacks.The challenge of working with the fluffy fibre is considered and the benefit of fibre alignment is highlighted for encouraging a widespread use of the fibre.
