A pneumatic regenerative system for a railway vehicle equipped with a plurality of axles includes a plurality of pneumatic drive mechanisms coupled to each of the plurality of axles. Each pneumatic drive mechanism includes an accumulator and a pneumatic device. The pneumatic device may in some examples be a reversible air motor device. The accumulator is operable to receive and store pressurized air. The reversible air motor device is coupled to the accumulator and one of the plurality of axles of the vehicle. The reversible air motor device is operable in a first configuration and a second configuration. During a braking operation of the railway vehicle, the reversible air motor device in the first configuration is driven by rotation of the one of the plurality of axles to generate and store pressurized air in the accumulator. During an acceleration operation, of the railway vehicle the reversible air motor device receives pressurized air from the accumulator to drive rotation of the one of the plurality of axles.

Methods of laser powering unmanned aerial vehicles (UAV) with heat engines are disclosed. The laser powered heat engines are used in conjunction with devices for absorbing laser optical radiation, turning the laser optical radiation into heat, supplying the heat to a working fluid of the heat engine and harvesting mechanical work from expanding working fluid in the heat engine.

This invention presents methods and system for conversion of heat to electrical power through absorption of heat from any types of fluids with temperatures both higher and lower than 0 C. Heat can be absorbed from fossil or renewable energy resources. The mechanism in this invention uses a fluid or fluids' enthalpy and internal energy difference to generate power, where a reciprocating piston-cylinder system provides the required force to rotate a turbine for power generation.

Filter assemblies and components therefor, are described. In an example arrangement, the filter assembly is configured to be serviced from either the top or the bottom. A rotational indexing arrangement is to ensure appropriate orientation of an internally received filter cartridge, and other components of the arrangement are provided. Methods of assembly, servicing and use are described.

An inlet-valve arrangement is for an external-heat engine, which includes at least one working chamber, each one having a cooperating piston. The working chamber is supplied with a working fluid via at least one controlled poppet valve. The poppet valve is arranged to open in the opposite direction to the flow direction of the working fluid. The center axis of the poppet valve is arranged perpendicularly within a deviation of 45 degrees relative to the center axis of the piston.