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Review of Sequences and Infinite Series
Published in Russell L. Herman, An Introduction to Fourier Analysis, 2016
The average speed of a large commercial jet airliner is about 500 mph. If you flew for an hour (measured from the ground), then how much younger would you be than if you had not taken the flight, assuming these reference frames obeyed the postulates of special relativity?
Effects of vertical vibration on sitting comfort in civil aviation during the cruising flight
Published in Ergonomics, 2023
We assigned vibration accelerometers to the seats and floor of the cockpit and the front, middle, and rear areas of the passenger cabin, respectively, during a flight of a large commercial airliner (Figure 1a). The aeroplane was a narrow-body jet powered by two engines with a capacity of 150–186 passengers. The airliner flight from Xi’an to Dunhuang and a simplified schematic diagram is shown in Figure 1c. The cruising speed was kept at around 800 km/h. This flight was explicitly organised for vibration measurement with only a group of the flight crew and vibration testing personnel (less than seven) during the flight. The vibration signals in the x-, y- and z-axis on the seat pan and seat-back behind a 75 kg dummy were acquired using seat pad accelerometers (PCB 356B41, 4# and 5# in Figure 1b) with a sensitivity of 10 mv/g, and on the floor were acquired using triaxial accelerometers (PCB 356B18, 7# in Figure 1b) with a sensitivity of 50 mv/g. An LMS SCADAS (120 channels) data acquisition system recorded all vibration signals at a sampling rate of 5120 Hz.
A CFD–CSD coupling method for simulating the dynamic impact and expulsion of fragile foreign objects from the ‘inlet–bypass duct’ junction of a turboprop aircraft
Published in Engineering Applications of Computational Fluid Mechanics, 2022
Turboprop aircraft have good environmental adaptability (Ashenden & Marwitz, 1997). They can take off and land normally on airstrips such as clay runways, sand runways and runways covered by grass and snow, and they can also adapt to bad weather. That is to say, this kind of aircraft ought to have enough tolerance to foreign objects that may appear on the runway or during flight, since these foreign objects may cause serious consequences when entering the inlet. In addition to affecting the efficiency of the inlet and reducing the performance of the engine, foreign objects may also damage the internal structure of the inlet or the engine and threaten flight safety. For this reason, in recent years, a kind of inlet with a bypass duct is gradually emerging and has been applied in a variety of advanced turboprop aircraft (Mi & Zhan, 2019) such as the DHC-8 turboprop aircraft and MA700 turboprop regional airliner in China. The bypass duct refers to a section of pipe connected to the outside of the engine at the end of the intake port of turboprop aircraft, which is mainly used to remove large foreign objects that cannot be swallowed by the engine. The application of this type of inlet–bypass duct is of great significance for improving the performance of advanced turboprop aircraft.
Innovation, transport security and supply chains: a review
Published in Transport Reviews, 2022
Nicola De Liso, Luca Zamparini
The first item is related to the intrinsic vulnerability (Mattsson & Jenelius, 2015) of each specific means of transport considered in itself, that is the individual aircraft, train, vessel, truck, etc. (Yap, van Oort, van Nes, & van Arem, 2018). For example, cabin pressurisation is fundamental for aircrafts, and any alteration of the pressure control system or a hole in the fuselage of the aircraft can be fatal to the crew – and the passengers, in case of a passenger airliner. Creating the conditions for the blowing out of a tyre of a truck carrying hazardous materials may be a low-tech, very effective – from the terrorists’ point of view – means to achieve the end. An exercise in order to make a list of intrinsic vulnerabilities for each means of transport can easily be carried out.