Pneumatic motor low engine temperatures. The Pneumatic Quasiturbine engine is a compressed air pistonless rotary engine using a rhomboidal-shaped rotor whose sides are hinged at the vertices. The Quasiturbine has demonstrated as a pneumatic engine using stored compressed air It can also take advantage of the energy amplification possible from using available external heat, such as solar energy. The Quasiturbine rotates from pressure as low as 0.1 atm (1.47psi). Since the Quasiturbine is a pure expansion engine, while the Wankel and most other rotary engines are not, it is well-suited as a compressed fluid engine, air engine or air motor. Armando Regusci's
Electric potential energy time-invariant electric fields. The electric potential energy of a system of point charges is defined as the work required assembling this system of charges by bringing them close together, as in the system from an infinite distance. ^\mathbf{r} q\mathbf{E}(\mathbf{r'}) \cdot \mathrm{d} \mathbf{r'}</math>, The electrostatic potential energy can also be defined from the electric potential as follows: The SI unit of electric potential energy is the joule (named after the English physicist James Prescott Joule). In the CGS system the erg is the unit of energy, being equal to 10 J. Also electronvolts may be used, 1 eV = 1.602×10 J.