Pyrolyzed waste plastic-based green fuel has been reported to be used as an alternate fuel for diesel engines. Some of the main challenges for implementing this in current automotive technology include evaluating engine performance, emission, noise vibration harshness (NVH), and knock characteristics of this fuel. This study focuses on the engine performance of poly-ethylene terephthalate (PET)-based waste plastic oil (WPO) at varying engine speed conditions. The pyrolysis of mixed-waste plastic was carried out at 300 °C in a fixed-bed reactor. Physicochemical properties such as viscosity, density, calorific value, sulfur, and research octane number (RON) of the plastic fuel and its blends with gasoline were analyzed using ASTM standard test methods. The WPO was blended with two different types of gasoline (RON88 and RON90) at 10, 20, and 30%, and was tested in a spark-ignition (SI) engine. The experimental results showed that different WPO–gasoline blends can be used in an SI engine without any engine modifications, and the performance indicators for different blends were found to be close to that of pure gasoline. The brake power and brake specific fuel consumption (BSFC) were found to be 4.1 kW and 0.309 kg/kW h, respectively. The 10% WPO and 90% RON90 blend produced optimal engine performance at 3500 rpm.

Steel construction is mostly connected by using a welding technique. The result of the welding process can cause the change of mechanical properties of the welding zone. Therefore, it needs to be reviewed to guarantee the quality of the welding zone. This research aims to assess the effect of welding on the change of microstructure and the mechanic characteristic of welded connection. Low carbon steel was welded by using Shield Metal Arc Welding method (SMAW) with electrode E7016, diameter 2,6 mm. Type of notch used was single V with angle 70° and welding position was 1G. Then, the Charpy impact test, Rockwell hardness and micro-macro structure monitoring on the welding zone including base metal, Heat Affected Zone (HAZ) and weld metal, are conducted. The results show that the highest impact toughness value at metal welding area is 251 joule/mm², and lowest impact toughness is at the heat affected area (HAZ) is 119 joule/mm². Hardness values of welding zones are found of about 87,6 HR_B for weld metal, 73,9 HR_B for HAZ zone and 67,1 HR_B for the base metal. The microstructure of weld metal zone, HAZ and base metal are included on ferrite and pearlite formed by welding on low carbon steel AISI 1010 observer by using an optic microscope.

Tube-type compact heat exchangers are one of the most commonly used heat exchangers in the industry. Compact heat exchangers are known for their large surface area to volume ratios allowing more optimal heat transfer rate. This study examines both the coefficient and the rate of convective heat transfer on the outer surface of a tube-type compact heat exchanger. The heat exchanger was configured in the sharp turns and spiral fin which is varied in pitch. The Fin pitches were 1 cm, 2 cm, 3 cm, 5 cm, and 7 cm. The length of the heat exchanger pass was 30 cm with a turn length was 8.2 cm and the total length of the heat exchanger was 6 m. Heat exchangers were made using galvanized pipes with an inside diameter (Di) 20 mm and an outside diameter (Do) of 22 mm, fins are made using aluminium with a thickness of 0.3 mm. Water was maintained at a constant temperature of 80 °C and circulated into the heat exchanger with a flow rate of 0.4 L/s. The air was blown using a fan with varying speeds of 2.4 m/s, 2.8 m/s and 3.4 m/s (the ambient air temperature was 28 °C). The results showed that the highest convection heat transfer coefficient and heat transfer rate occurred in the heat exchanger with a fin pitch of 2 cm, because the turbulence was more optimal and fewer airflow losses. In the heat exchanger with a fin pitch of 3 cm, 5 cm and 7 cm has a large gap between the fins so that turbulence is not optimal while in the heat exchanger with a fin pitch of 1 cm the gap between the fins is too small so that it inhibits the rate of airflow.