The free-piston Stirling engine is a closed-cycle regenerative heat that converts energy into mechanical work, and requires spring element for vibratory operations of the displacer power pistons. In this study, geometry flexural design was optimized through structural finite analyses fatigue test evaluations. First, we constructed target space considering required natural frequency assembly und...

Gas leakage is one of the main sources inefficiencies in low-capacity reciprocating compressors, undermining compressor performance by reducing mass flow rate and increasing energy consumption. In piston–cylinder clearance driven piston motion pressure difference between compression chamber internal environment shell. This paper reports a parametric numerical analysis compressor. A simulation m...

This controlled study compared the strength and porosity of 48 polymethylmethacrylate cement-implant constructs prepared with open bowl versus vacuum mix technique. Forty-eight blast finished stainless steel rods of 13 mm diameter were implanted with centralizers into 17-mm inner diameter tubes that had been retrograde filled with polymethylmethacrylate cement. The eight cement preparations use...

Free-piston diesel engines are characterized by freely moving pistons without any crankshaft or camshaft connected to the pistons. This allows a compact and efficient engine design, but requires automatic control of the piston motion. This paper present a dynamic mathematical model of a free-piston diesel engine, and a control oriented dynamic analysis leading to a piston motion control structu...

A bowl-shaped nitrogen-doped nanographene composed of a pyrrolo[3,2-b]pyrrole core substituted with six arene rings circularly bonded one another undergoes bowl-to-bowl inversion low barrier. This resembles that an umbrella flipped by the strong wind. The transition state is not planar, but possesses rather twisted, S-shaped conformation Ci symmetry. bowl-inversion mechanism follows quadruple-w...

Bowl-in-bowl stacking of buckybowls on a copper surface is observed via scanning tunneling microscopy (STM) at low temperatures and characterized by density functional theory (DFT) calculations.

The synthesis and characterization of two direct platinum (1 and 6a/b) and three ethynyl-platinum corannulene derivatives (2, 8 and 9), bearing 2, 4, or 5 square planar platinum centers, are presented. The structure of the bowl bearing substituents remains comparable to corannulene and the dynamic behavior of the bowl inversion as assessed by VT NMR supports a persistent bowl structure in solut...

Free-piston engines are under investigation by a number of research groups worldwide, as an alternative to conventional technology in applications such as electric and hydraulic power generation. The piston dynamics of the freepiston engine differ significantly from those of conventional engines, and this may influence in-cylinder gas motion, combustion and emissions formation. Due to the compl...