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This study aims to know the effect of resin and hardener ratio of epoxy matrix on the manufacture of carbon fiber composite materials using the VARTM printing method on the mechanical properties of carbon fiber composites and to know the best formulation between resin and hardener used in the VARTM printing methods. This research is an experimental study, with the subject being a carbon fiber composite test sample made using the composition of resin and hardener epoxy matrix ratios that were varied and printed using the VARTM method. The resin and hardener ratios of an epoxy matrix are 60%:40%, 70%:30%, and 80%:20%. Processing and analysis of test data using descriptive statistical methods. The results of this study indicate carbon fiber composites printed by the VARTM method, the 70%:30% ratio, in higher tensile and flexural strengths of 10.8% and 35. 7% respectively, compared to the ratio of 60%:40%, while the 80%:20% resin and hardener ratio, a decrease in tensile and flexural strength respectively by 21% and 45.3% when compared to the 60%:40 % ratio. In addition, the 60%:40% ratio is the lowest density compared to 70%:30% and 80%:20% ratios. Next, the best formulation of resin and hardener ratio to increase the strength of carbon fiber composites printing using the VARTM method is 70%:30%. In contrast, for the density value, the best formulation is 60%:40%. [ABSTRACT FROM AUTHOR]

Wheelchairs are a basic need for people with disabilities, especially people with physical disabilities. Although conventional wheelchairs have helped the mobility of people with disabilities, they are in short range due to biological fatigue factors. In the concept of inclusion, there is equality in various aspects of life so that everyone can live together and equally without exception, including people with disabilities. Thus, technology development is needed to help people with disabilities to achieve equality in mobility, especially when using wheelchairs. This can be achieved by developing manual wheelchairs into electric wheelchairs (Electric wheelchairs), with the addition of electric motors for drive and other supporting features. The study aimed to establish the features and specifications of IoT-based electric motors in wheelchairs for the convenience and comfort of mobility of people with disabilities—development based on the results of last year's research. The research method used is the Research &Development method. The research and development results show that the power transfer mechanism for wheelchair electric motors uses two pulleys. The drive mechanism using Pulley and Belt is suitable for low torque and speed use. Because the speed of the electric motor for this wheelchair will be limited to a maximum of 6-12 km/hour, with the aim of safety. The pulleys used use Aluminum material. The drive pulley that gets power from the motor is made smaller than the driven pulley that is placed on the wheel axle of the wheelchair. With the comparison of these sizes, the resulting rotation will be smoother. [ABSTRACT FROM AUTHOR]

This study aims to find the effect of changes in the compression ratio on performance and fuel consumption on the Yamaha Vega Force Fi engine with ethanol fuel (E100) and find the most optimal compression ratio for the Yamaha Vega Force engine with ethanol fuel (E100). The type of research is experimental research with three variations of compression ratio as the research object in the Yamaha Vega Force Fi engine. The test was carried out with a dynojet 250i chassis dynamometer and burette to measure torque, power, and fuel consumption. The data analysis technique used to process data from the test result used descriptive analysis. The result of this study indicates that a compression ratio of 13,5:1 produces the most optimal performance and is the most efficient fuel consumption for the Yamaha Vega Force Fi engine with ethanol (E100) fuel. Increasing the compression ratio from 12:1 to 13,5:1 has an impact on increasing the torque achievement by 14%, increasing achievement engine power by 9%, and improving the brake-specific fuel consumption (BSFC) by up to 11%. [ABSTRACT FROM AUTHOR]

Goal of this research were: (1) produced front wing aerodynamic design; (2) generated downforce coefficient which produced by the front wing; (3) generated aerodynamic efficiency level of front wing device which is used by Formula Garuda to compete in Student Formula Japan. This research is a type of research and development (Research and Development) using the 4D development model, including define, design, develop, and disseminate. The research object was front wing aerodynamic design of formula car which compete in SFJ. Software SolidWorks was used as data collection tool, with Computational Fluid Dynamic (CFD) data analysis technique. CFD result data showed as number and image based on the shape of the front wing design and angle of attack changes. Result of this research showed: (1) there were three variants of front wing design according to the FSAE Rules, namely a single element wing, multi element wing with 1 winglet, and multi element wing with 2 winglet equipped with endplates and footplates; (2) the maximum downforce coefficient was 3,29 which produced by multi element with 1 winglet of wing at AoA 160; (3) highest efficiency level of front wing was 5,19 on single element wing at AoA 90. Based on the conditions of the SFJ competition track, the front wing with a high downforce coefficient is suitable for use in formula cars. [ABSTRACT FROM AUTHOR]

The MY1016 DC motor is a popular choice among hobbyist for electrification of bicycle and scooter. With frequent acceleration and deceleration, the fluctuating current drawn from the power supply increases the motor temperature. In this study, we develop a temperature-integrated motor controller that allows us to control the speed profile of the motor and evaluate several motor components' temperature when it is operated in several standard electric motorcycles, IEC. It was shown that the highest temperature inside the motor is the brush, followed by the bearing and the permanent magnet. SI which is the steady state IEC cycles generates the highest temperature on the brush at 81°C, while S5 which is an intermittent periodic with electric braking cycle generates the lowest temperature at 45°C. Any abrupt acceleration with a duration less than 10 seconds has no consequence on the temperature of the machine. [ABSTRACT FROM AUTHOR]