Provided are magneto-cryogenic valves, methods and systems that extract thermal energy from a fluid within a conduit such that the temperature of at least a portion of the fluid is reduced to a temperature below which at least a portion of the fluid becomes a solid thereby forming a frozen plug of fluid and magnetically susceptible particles that reversibly plugs the conduit, preventing flow of fluid past the plug. Also provided are methods and systems for temporarily preventing the flow of fluid in a conduit.

Drag experienced by a vehicle traveling through an environmental media, such as air or water, may be modified by one or more energy beams which may increase or decrease drag. A control system may be used to actively modulate the drag of the vehicle by selectively transmitting energy beams. Energy beams may include electric pulse signals, pulsed air, piezoelectric, infrared, ultraviolet, laser, optical band, microwave, thermal other known acoustic, electric, optical, or other electromagnetic energy and any combination thereof. This could be a constant or pulsed energy beam and adjusted for the speed and/or vertical lift, frequency, density, angle, pulse and wavelengths experienced by the vehicle. Charged particles may be emitted from the vehicle itself and then utilized in front or behind the vehicle via electric current to improve the boundary layer, boundary flow.