In this work, naturally available moringa oleifera leaves are chosen as a heterogeneous catalyst for biodiesel production from palm oil. The dry moringa oleifera leaves are calcinated up to 700 °C for 3 hours to improve their adsorbing property. The calcinated catalyst characterization analysis from XRD and EDX highlights the presence of calcium, potassium, and other elements. Response surface method (RSM) optimization and artificial neural network (ANN) modeling were carried out to elucidate the interaction effect of significant process variables on biodiesel yield. The results show that a maximum biodiesel yield of 92.82% was achieved at optimum conditions of catalyst usage (9 wt.%), molar ratio (7:1), temperature (50 °C) and reaction time (120 min). The catalyst usage (wt.%) was identified as a significant process variable followed by molar ratio. Furthermore, the significant fuel properties of the biodiesel related to thermal, physical, chemical, and elemental match with the established standards of ASTM. The reutilization analysis of the catalyst reveals that more than 50% of the biodiesel yield was achieved after five cycles of reuse.
Solar radiation causes excessive temperatures in the cabin of a car parked in direct sunlight. Excess temperatures can accelerate damage to interior compartments, increase the evaporation of benzene from interior components, and increase the AC load when the vehicle starts. Therefore, this article presents the results of an investigation on the energy conversion of solar cells mounted on the car roof to activate electric blowers (mini air cooler). Two Nissan Grand Livina with and without mini air cooler is placed in areas exposed under direct sunlight. Then, the temperature data is sent and processed with DAQ master. The results showed the mini air cooler was able to reduce the cabin temperature to 6°C.
The emergence of Corona Virus Disease 19 (Covid-19) required a new method to control its spread. During this time, controlling COVID-19 was carried out by implementation of a sterilization chamber using a liquid-based disinfectant. However, the use of liquid-based disinfectants has been evaluated to be less effective because it allows disrupting the respiratory tract. Therefore, this work presents a negative pressure sterilization chamber using Ozone and UV-C lamp. Ozone has been recommended by the Indonesian Institute of Sciences (LIPI) as a substitute for liquid-based disinfectants. In addition, to maximize performance, the chambers are added with UV-C lamps. The negative pressure sterilization chamber with Ozone and ultraviolet lamps was successfully created with the main parts of the cubicle chamber, an Ozone generator, at least one ultraviolet lamp, exhaust fan, switch, and a timer. The negative pressure sterilization chamber with Ozone and ultraviolet lamps according to this work, where the Ozone supply from the Ozone generator is made automatically to the door opening and closing. The duration of the Ozone supply was regulated by a timer. Then, the ultraviolet lamp can be activated together with Ozone or independently. With the implementation of this sterilization chamber, the spread of the Covid-19 virus is expected to be suppressed in a safer way than using liquid-based disinfectants.
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