Only with the high exit velocities possible with pulsed laser ablation propulsion is it possible to overcome this problem.
The gradient in muscle tension created along the intestine (increased in jejunum and decreased in ileum) may promote propulsion of worms in the lumen.
Propulsion obtains the dimensions it requires from hull, determines the ver tical center of gravity for stability, and provides total thrust to resistance.
This hopper included a translational offset mass in order to cause the tipping action that helped in forward propulsion.
This is a useful generalized account, serving as an introduction to the short discussion of hypersonic propulsion that is given later.
Also, carangiform propulsion is more convenient for engineering realization.
Calculated efficiencies are found to be insufficient for propulsion applications that require short periods of acceleration but ion-beam propulsion shows some potential for prolonged flights.
Here, the selective pressures for efficient maintenance of high-speed propulsion appear to be responsible for the convergent evolution of caudal fins of high aspect ratio.
