In this study, a gamma type Stirling engine was produced and tested for the micro-CHP system with a swept volume of compression 106 cc. The engine is tested by air and uses LPG fuel as a heat source. Air pressure at the beginning of the compression process is considered to be the ideal gas pressure of 0.987 bar. The best working characteristics of the machine were obtained in the first test with a temperature difference on the hot and cold side of an average of 74.7°C. Maximum output and power output were obtained at 1.82 bar charge pressure of 242.6 rpm and 12.9 W. The results found were encouraging to begin the prototype gamma type Stirling engine for micro-CHP applications.

The aim of the study to investigate the effect of welding current on the microstructure and mechanical properties of gas tungsten arc welding (GTAW) for dissimilar austenite Stainless steel (AISI 309 and 201). Three models of welding currents have been used and their effect on microstructure and mechanical properties investigated. The results reveal that increase of welding currents improved the ultimate tensile strength (UTS) however, the hardness of the weld zone and Heat Affected Zone (HAZ) are similar. On the other hand, the microstructure of base metal AISI 309 and 201of austenite, ferrite structure, and ẟ ferrite of AISI 309 stainless steel were observed.