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Makara Journal of Technology
Published by Universitas Indonesia
ISSN : 23552786     EISSN : 23564539     DOI : https://doi.org/10.7454/mjt
Core Subject : Science, Engineering,
Chemical Engineering, Chemistry & Bioengineering Civil Engineering, Building, Construction & Architecture Electrical & Electronics Engineering Engineering Materials Science & Nanotechnology Mechanical Engineering
MAKARA Journal of Technology is a peer-reviewed multidisciplinary journal committed to the advancement of scholarly knowledge and research findings of the several branches of Engineering and Technology. The Journal publishes new results, original articles, reviews, and research notes whose content and approach are of interest to a wide range of scholars. It also offers rapid dissemination. MAKARA Journal of Technology covers the recent research in several branches of engineering and technology include Electrical & Electronics Engineering, Computer Engineering, Mechanical Engineering, Chemical & Bioprocess Engineering, Material & Metallurgical Engineering, Industrial Engineering, Civil & Architecture Engineering, and Marine Engineering. Criteria used in determining acceptability of contributions include newsworthiness to a substantial part of the engineering & technology and the effect of rapid publication on the research of others. This journal, published three times each year, is where readers look for the advancement of discoveries in engineering and technology.
Arjuna Subject : Teknik (semua kategori) - Teknik (Lain-Lain)
Articles 6 Documents
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Search results for , issue "Vol. 26, No. 3" : 6 Documents clear
Ultrasound Application for Oil Extraction of Lemongrass Parts Yuniarto, Kurniawan, Mr; Welt, Bruce Ari, Prof; Muvianto, Cahyo Mustiko Okta, Dr; Muiz, Abdul, Mr
Makara Journal of Technology Vol. 26, No. 3
Publisher : UI Scholars Hub

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Abstract

Power ultrasound creates acoustic cavitation bubbles that encourage shears within food substances. Applying ultrasound improves solvent diffusion into the matrix plant cellular and hence breaks down bioactive substances. This research aims to extract lemongrass oil using ultrasound-assisted extraction (UAE). The essential oil was extracted from different lemongrass parts, such as corm, stalk, and leaf. Then, a 37 kHz UAE was applied below the solvent vapor pressure temperature under different periods, i.e., 15, 30, and 60 min. The solvent temperature logarithmically increased from 28 ℃ to 53 ℃ during 20 min of the ultrasound treatment. Acoustic power was obtained from a graphic plot by approximately 35.68 kJ for the initial 20 min and by 31.14 kJ for the remaining UAE period. The lemongrass oil obtained a higher yield from the corm section about 3 and 1.4 times compared to stalk and leaf components. The extracted lemongrass oil produced a yellowish color from the leaf and stalk and a yellow-red color from the corm. The refractive index varied between 1.389 and 1.422, and the specific gravity was from 0.89 to 0.97 g/cm3 . The lemongrass leaf produced the highest citral content and more saturated lipid acids than unsaturated in the lemongrass essential oil.
Utilization of Biopertalite for Fuel Efficiency and Reduction in CO and CO2 Gas Emissions in Four-Wheel Motor Vehicles Iskandar, Ridwan; Hadiyanto, Hadiyanto; Suherman, Suherman; Zakaria, Zainul Akmar
Makara Journal of Technology Vol. 26, No. 3
Publisher : UI Scholars Hub

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Abstract

Emissions of carbon monoxide (CO) and carbon dioxide (CO2) gases are the main problem that must be rectified as they are harmful and contribute to global warming through the greenhouse gas effect. In Indonesia, motor vehicles, especially four wheelers, are one of the biggest contributors with up to 71 million tons of CO2 emissions and energy consumption of 179 million barrel of oil equivalent. Bioethanol has octane rating >100, which is higher than that of gasoline; and emission contribution of only 0.02 kg/L, which is lower than that from gasoline (2.23 kg/L). Accordingly, a mixture of gasoline and bioethanol is the solution proposed in this study to solve the issues of CO and CO2 emissions. Gasoline and bioethanol mixture consists of six products, namely E-0, E-5, E-10, E-15, E-20, and E-25, which have different percentage values of bioethanol mixture (0%–25%). This study was conducted through engine testing with different rpm values (500–2500 rpm) to identify the concentration and mass of CO2 emissions, fuel efficiency, and cost efficiency. Based on the test results, this product succeeded in reducing CO emissions by up to 86% and CO2 emissions up to 30.6% from Pertalite (E-0) and increasing the fuel efficiency up to 51.76% for 1 L and cost efficiency up to 33.6% after considering the actual price of Pertalite. Therefore, the proposed product can be a solution to the existing problems.
Design and Prototyping of a Low-Cost High Frequency Antenna for Vicinity Coupling Devices Kommey, Benjamin; Addo, Ernest Ofosu; Tamakloe, Elvis
Makara Journal of Technology Vol. 26, No. 3
Publisher : UI Scholars Hub

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Abstract

This paper describes the development of a high frequency (HF) antenna for high output power vicinity coupling devices (VCDs) operating at 13.56 MHz. Key design parameters, such as RF power level, antenna size, and communication protocol, and their link to the antenna features and requirements, have been discussed. For efficient reader interrogation, detection, and recovery of transponder responses, a tuning circuit necessary to adjust the antenna power matching and resonance characteristics was designed and prototyped. The antenna was fed to an industry standard reader and evaluated for read range performance with vicinity cards. The designed antenna on the reader achieved a good read range, which demonstrated fair agreement with the calculated theoretical results.
Investigation of the Characteristic Thermal Retention Behaviour of Sandwich Glass-Fibre-Reinforced Composite Panels in Electric Oven Designs Agbo, Cornelius Ogbodo Anayo
Makara Journal of Technology Vol. 26, No. 3
Publisher : UI Scholars Hub

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Abstract

The focus of this paper is to experimentally investigate the characteristic heating and cooling behaviours of a sandwich glass fibre reinforced composite panel electric ovens. A portable conventional electric oven with two stack trays for product placement was designed and fabricated for the evaluation. The oven box consists of sidewalls and a ceiling made of glass-reinforced plastic (GRP) with sandwich glass wool insulation. The oven floor has, in addition to the sandwich panel, a ceramic tile plate placed on the chamber floor to separate the electric heating element. The oven characteristic thermal behaviour was obtained as different product load conditions were being simulated. The heat retention ability of the oven is quite impressive making it possible for the water simulated product to remain warm for up to 13 hours with the testing stockpot open and more than 27 hours with the pot covered. Energy is therefore conserved as the oven can be switched off while the product continues to process. The oven cooking efficiency of approximately 39% was obtained under standard stockpot water test. The oven is therefore suitable for both culinary activities and laboratory experiments requiring moderate temperatures.
Supermarket and Water Spider Concept for Improving Door Sub-Assembly Productivity Barnas, Andreas; Pratama, Aditya T.; Awibowo, Setijo
Makara Journal of Technology Vol. 26, No. 3
Publisher : UI Scholars Hub

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Abstract

This research is based on a case study at the door sub-assembly area of a German car manufacturer in Indonesia. The door sub-assembly area is responsible for assembling doors to be supplied to the specific station in assembly line that will assemble the finished doors to the car. The area had a problem in supplying the doors to the main assembly line on time. This means, the cycle time of door sub-assembly is higher than that of the assembly line. After observation, the factor that greatly contributes to the high cycle time can be identified, which is motion waste. Therefore, a unique approach is offered to overcome the situation, which involves re-designing work system and work area. The approach is to implement new working system by adopting lean tool water spider to significantly reduce motion waste. In the end, the initial and after condition will be contrasted to see the improvement made by this research. The results of this study could give the company several benefits: improved working efficiency of workers, reduced cycle time in door assembly and reduced fatigue of workers.
Damage Stability Study of A 500 DW Ro-Ro Ferry Vessel Ariany, Zulfaidah; Santoso, Budhi; Sarwoko, Sarwoko; Prasetyo, Nauval Abdurrahman
Makara Journal of Technology Vol. 26, No. 3
Publisher : UI Scholars Hub

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Abstract

The development of the crossing transportation industry is currently increasing in the island areas. The use of Ro-Ro type ferry boats is extremely efficient in moving people, goods, and vehicles. The current research focuses on the damage stability of the 500 DWT Ro-Ro ferry, which aims to meet the needs of the Ro-Ro ferry in the archipelago area. The previously existing initial design of a barge hull with a main size Lpp = 40.15 m, B = 12 m, H = 3.2 m, and T = 2.15 m was used to analyze the damage stability condition further. First, the drawings were redrawn. Then, 3D modeling was performed and the tanks were inspected. The processing of the input data design was finally tested under several criteria based on damage stability in SOLAS 2009. This study concluded whether the 500 DWT Ro-Ro ferry design is acceptable considering damage stability. The GZ value is standardized in the scenario of calcge stability of the Ro-Ro ferry as a whole. Attention should be provided to the range of positive stability in intermediate stages considering the forward damage case, wherein the ship departs and the full load experiences failure.

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