Abstract: The current invention is a closed cycle heat engine that includes a plurality of variable volume movable working chambers, each chamber having a first volume of working fluid when disposed at an isentropic expansion zone leading edge, a second volume when disposed at an isentropic expansion zone trailing edge, a third volume when disposed at an isentropic compression zone leading edge and a fourth volume of working fluid when disposed at an isentropic compression zone trailing edge. The second volume of working fluid divided by the first volume of working fluid provides a first volume ratio. The third volume of working fluid divided by the fourth volume of working fluid provides a second volume ratio. The first volume ratio equals the second volume ratio. The working fluid efficiently performs work by traversing a cycle consisting of an isothermal expansion, an isentropic expansion, an isothermal compression, and an isentropic compression.

Abstract: The invention is a spherical dome consisting of continuous prismatic members in three layers, an outer layer, a middle layer, and an inner layer. The continuous prismatic members follow great circle arcs. The members of the three layers form a three-way grid, crossing at the vertices of contiguous spherical triangles. Three members, one from each layer, are connected together at each vertex with fasteners, such as bolts, rivets, or welds. The continuous prismatic members of each layer can be spaced as desired to provide structural integrity, economy, and simplicity of construction. A tension ring, when required structurally, is provided at the bottom periphery of the dome to resist the vertical and horizontal forces generated by the supported loads. The combined elements provide a simple and economical spherical dome.