Abstract: Regular tetrahedral lattices (RTL's) can be used as building blocks in continuous one, two, and three-dimensional structures of superior lightness, strength, and rigidity. Such lattice structure can be thought of as consisting of at least 3 imaginary, edgeless cubic cells, wherein each cell contains a pair of RTL's and each RTL pair is formed entirely from six right-angle crossing elements of equal arm length and joined at eight vertices. Each of the eight vertices corresponds to a corner of one imaginary cubic cell and each of said cubic cells, together with each of said RTL pairs, shares an interface with at least one other cubic cell and RTL pair of said lattice structure. These structures can be formed into straight-line chains, make ninety-degree turns and three-dimensional right-angle crosses, thereby lending themselves to conventional construction with simple fabrication methods and rapid repairs in place.

Abstract: A working fluid in the gaseous state at some initial temperature and pressure is expanded polytropically to a resulting exhaust fluid having some lower temperature and pressure in order to produce useful work. Large quantities of a pressured motive liquid are then employed as the vehicle for approximating an isenthalpic compression of the working fluid. The preferred method for effecting this recompression is to provide an overall adiabatic environment within which the two fluids are placed in thermal but not physical communication. The working fluid is then energized by direct compression during which partial condensation of the working fluid is accompanied by heat transfer to the motive liquid. Thereafter the two fluids are mixed, with the resulting two phases permitting separation and reconstitution of the motive and working fluids to their initial states to complete the thermodynamic cycle which, depending upon the fluids selected, can be located in a broad range of the temperature spectrum.

Abstract: A working fluid in the gaseous state at some initial temperature and pressure is expanded polytropically to a resulting exhaust fluid (vapor and liquid) having some lower pressure at some lower temperature in order to produce useful work. The exhaust fluid is then, in a manner approaching constant enthalpy, compressed to the working fluid's nominal original high pressure. Thereafter, the fluid undergoes constant pressure heating to restore its initial state. Of the several methods described for achieving isenthalpic compression, the preferred method uses an isenthalpic compression apparatus which educts the exhaust fluid vapors into a throat located between a motive fluid inlet nozzle and a wider recompression outlet. After eduction, and entrainment into the motive fluid, the exhaust vapors are recompressed by the deceleration produced at the recompression outlet. Thereafter the working fluid and motive fluid are separated.