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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 15 Documents
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Search results for , issue "Vol. 15, No. 1" : 15 Documents clear
The Solvent Effectiveness on Extraction Process of Seaweed Pigment Warkoyo, Warkoyo; Saati, Elfi Anis
Makara Journal of Technology Vol. 15, No. 1
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Abstract

Eucheuma cottonii seaweed is a species of seaweed cultured in Indonesian waters, because its cultivation is relatively easy and inexpensive. It has a wide variety of colors from green to yellow green, gray, red and brown, indicating photosynthetic pigments, such as chlorophyll and carotenoids. An important factor in the effectiveness of pigment extraction is the choice of solvent. The correct type of solvent in the extraction method of specific natural materials is important so that a pigment with optimum quality that is also benefical to the society can be produced. The target of this research is to obtain a high quality solvent type of carotenoid pigment. This research was conducted using a randomized block design with three (3) replications involving two factors namely solvent type (4 levels: aceton, ethanol, petroleum benzene, hexan & petroleum benzene) and seaweed color (3 levels: brown, green and red). Research results indicated that each solvent reached a peak of maximal absorbance at λ 410-472 nm, namely carotenoids. The usage of acetone solvent gave the best pigment quality. Brown, green and red seaweed have pigment content of 1,28 mg/100 g; 0,98 mg/100 g; 1,35 mg/100 g and rendement of 6,24%; 4,85% and 6,65% respectively.
Cradle to Gate Simple Life Cycle Assessment of Biodiesel Production in Indonesi Hidayatno, Akhmad; M. Zagloel, Teuku Yuri; Purwanto, Widodo Wahyu; Carissa, Carissa; Anggraini, Lindi
Makara Journal of Technology Vol. 15, No. 1
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The focus of this research is to analyze potential environmental impact in the supply chain of palm oil biodiesel industries. Simple Life Cycle Assessment (LCA) is applied to analyze impacts, produced by the three main units in the supply chain of Palm-Oil-based Biodiesel, which are Palm Plantation, CPO mill, and Biodiesel Plant. We developed LCA calculation model using spreadsheet software, used to assess a number of input scenarios to evaluate the best scenario, in variation of: land quality, land area and the rate of clearing, land clearing technique and type of the original land. The biggest potential environmental impact is the contribution to global warming impact which emissions are produced mostly from unit plantation. Although plantation has biggest potential to contribute to environmental impact, it also gives biggest reduction to global warming impact. In general, the biggest environmental impact in the LCA category is climate change, followed by photo-oxidant formation and eutrophication. The biggest impacts in the supply chain are from the plantation, especially when choosing the right technique for land clearing. In addition, due to LCA linearity nature, the scenario that we tested does not change the total accumulative environmental impacts.
Characterization of Surface Active Shell Charcoal Nyamplung Seeds (Calophyllum inophyllum Linn) Wibowo, Santiyo; Syafi, Wasrin; Pari, Gustan
Makara Journal of Technology Vol. 15, No. 1
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Characterization of Surface Active Shell Charcoal Nyamplung Seeds (Calophyllum inophyllum Linn). Chemical and physical activation of nyamplung shell with 0%, 5%, and 10% H3PO4 for 60 and 120 minutes has been carried out to prepare activated charcoal. The purpose of this experiment was to look into the characteristic of nyamplung shell activated charcoal surface. Nyamplung shell was carbonized into charcoal, then activated by immersion in H3PO4 solution using 0%, 5% and 10%, for 24 hours, and heated in retort at two temperatures (700 and 800 oC) and two duration (60 and 120 minutes). The material were characterized by fourier transform infra red (FTIR), scaning electron microscope (SEM) and X-ray diffraction (XRD). The FTIR spectrum show that activated charcoal has OH, C-H, C-O and C=C bonds. The bonds of OH and C-O indicated that the treatment was produced polar activated charcoal. The porous texture was influenced by H3PO4 concentration. The porous with dimension <5 >μ being predominant at low concentration of H3PO4 (0% and 5%) but larger amount of H3PO4 (10%) produced wide pore with dimension >5 μ.
An Investigation Into the Resistance/Powering and Seakeeping Characteristics of River Catamaran and Trimarana Murdijanto, Murdijanto; Utama, I Ketut Aria Pria; Jamaluddin, Andi
Makara Journal of Technology Vol. 15, No. 1
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The increase of fuel price has caused fleet operational and shipping business to be in danger situation. The fuel consumption of a ship is influenced by ship volume or wetted area which contributes directly to the increase of ship resistance and the size of main engine. In order to find out the appropriate answers, a series of investigation into river transportation using monohull, catamaran and trimaran types of vessel was carried out. The work focused on the estimation of total resistance and powering as well as seakeeping characteristics and carried out experimentally using tank test and numerically using a ship design software (Maxsurf). It was found out that the catamaran and trimaran could have less resistance and hence power compared to monohull of similar displacement. The seakeeping characteristics of the multihull vessels were also comparable with those of the monohull. This is a good indication that river catamaran/trimaran is an efficient and comfortable vessel. If a prototype or real vessel is developed, it can be a very efficient ship as well as a ship with high safety standard.
Production of Lovastatin and Sulochrin by Aspergillus Terreus Using Solid State Fermentation Dewi, Rizna Triana; Artanti, Nina; Mulyani, Hani; Lotulung, Puspa Dewi Narrij; Minarti, Minarti
Makara Journal of Technology Vol. 15, No. 1
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Abstract

Lovastatin is an anti-cholesterol agent that was produced by Aspergillus terreus using solid state fermentation (SSF). During this fermentation process, sulochrin is also produced as an unwanted co-metabolite. However, our previous result showed that sulochrin had potential as antidiabetes because it is an inhibitor agent of α-glucosidase. In this paper, we reported our observation on lovastatin and sulochrin production pattern in relation with inhibitor α-glucosidase activity during eleven days fermentation of A. terreus koji (SSF) ethyl acetate extract. Koji obtained from solid state fermentation with rice as the substrate and incubated at room temperature, sample is taken daily for eleven day (D-1 to D-11). Lovastatin and sulochrin production was measured by Liquid Chromatography- Mass Spectrometer based on their molecular weight m/z 404.5 and 332.3 respectively. The inibitory activity is measured by inhibition model of koji extract against α-glucosidase (EC 3.2.1.20) from Saccharomyces cereviceae. The results show that lovastatin production was started on the day 2 (0.04 mg/g) and achieving the optimal production on day 7 (11.46 mg/g), while sulochrin production was started on day 4 (0.60 mg/g) and keep produced until the end of fermentation period at Day 11 (3.11 mg/g). Koji extract was started to show inhibitory to α-glucosidase activity on Day 5 (IC50= 23.34 μg/mL) and keep showed activity until Day 11 (IC50=3.33 μg/mL). These results suggest that inhibitory activity of koji extract to α- glucosidase activity have relation with sulochrin biosynthesis production.
Natural Gas as Petroleum Fuel Substitution: Analysis of Supply-Demand Projections, Infrastructures, Investments and End-User Prices Tjandranegara, Abdul Qoyum; Arsegianto, Arsegianto; Purwanto, Widodo Wahyu
Makara Journal of Technology Vol. 15, No. 1
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Abstract

The petroleum fuels (PF) subsidy has long burdens the government spending, and discourages less expensive energy usage such as natural gas (NG). Exporting NG and importing the more expensive PF products cause financial losses to Indonesia. The lack of NG infrastructure is the main hurdle in maximizing domestic NG usage and so does the perception of its high investment costs burdening government spending and pushing the NG transportation cost up. This study calculates the required NG infrastructure and its investments for several levels of PF substitutions up to 2030. To balance the NG demands, the supply from each field and its corresponding infrastructures needed was calculated and optimized using non-linear programming with generalized reduced gradient method to calculate the lowest transportation cost for the consumers. The study shows with a favorable return on investments attractive to private investors, the NG prices can still be put much lower than PF prices, allowing subsidy, import and production cost savings in many sectors. Furthermore, the highest level of substitution scenario needs only US$ 2.07 billion a year investment, very low compare to the current US$ 14.17 billion a year PF and electricity subsidy.
The Formation Design of Noise Reducers from Plywood, Foam, Tray, dan Coconut Fiber for Static Sources Fachrul, Melati Ferianita; Yulyanto, Wisnu Eka; Merya, Asharani
Makara Journal of Technology Vol. 15, No. 1
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The Formation Design of Noise Reducers from Plywood, Foam, Tray, dan Coconut Fiber for Static Sources. Research was conducted in a semi-anechoic room using a method referring to the ISO 3745. The design used is the Hemisphere in which the source of noise is analogous to engines in an industry. The value reduction in the rate of sound power is obtained by comparing the sound power level before and after control is given. The noise control test materials used consist of layers of plywood, foam, fiber and tray (egg box). The effectiveness of these materials is tested by measuring the sound transmission loss (STL). Test results reveal that the sound power level (Lw) of the source of noise produces a high Lw which is 99.6 dB. at a frequency of 8000 Hz. The measurement of Lw on the source of noise which is covered by plywood produces a total of 78.66 dB Lw with an Lw reduction of 21.02%. The measurement on the sound source covered by plywood and foam materials produces a total of 47.79 dB Lw with an Lw reduction of 52.02%. The measurement of Lw by combining plywood, foam, and tray produces a total of 33.02 dB Lw with an Lw reduction of 66.84%. The measurement of the total Lw after being covered by plywood, foam, fiber, and tray is a total of 31.94 Lw dB with an Lw reduction of 67.93%.
Ergonomic Analysis of Garment Industry using Posture Evaluation Index (PEI) in Virtual Environment Muslim, Erlinda; Nurtjahyo, Boy; Ardi, Romadhani
Makara Journal of Technology Vol. 15, No. 1
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Ergonomic Analysis of Garment Industry using Posture Evaluation Index (PEI) in Virtual Environment. This research tried to study, in a virtual environment, the ergonomics of four divisions in garment industry: cutting division, sewing division, button division, and finishing division. Variables that influence the working conditions in each division are different; depend on the real situations that happened. The purpose is to assess the real working conditions based on ergonomics study using Posture Evaluation Index (PEI). PEI integrates the scores of low back analysis (LBA), ovako working posture (OWAS), and rapid upper limb assessment (RULA). Analysis phase was done using digital human model in virtual environment that available on Jack 6.0. The results show that the working conditions in garment industry had enough amount of risk that can injured the musculoskeletal system of the workers. This research enriches the body of ergonomics knowledge in Indonesia because it is the first research in Indonesia that applied virtual environment approach to ergonomics analysis in industry.
The Zonation of Abration Speed Characteristics and its Handling Technique of Jalinbar of North Bengkulu as Vital Band Transportation Suwarsono, Suwarsono; Supiyati, Supiyati; Suwardi, Suwardi
Makara Journal of Technology Vol. 15, No. 1
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The Zonation of Abration Speed Characteristics and its Handling Technique of Jalinbar of North Bengkulu as Vital Band Transportation. Jalinbar Bengkulu is a vital infrastructure for traffic service, goods, agriculture products, mining, plantation and oils distribution. Abration due to scour of seawater often make these roads jammed and discrupts the peoples economy movement. The aims of this research was to investigate the abration speed of all segment of Jalinbar. The research method was a combination of two methods: A determination of swash energy of sea water using photometer and determination of rocks binding energy using douche method. The result shows that the maximum abration speed was in north area of Bengkulu beach, occurred in Air Dikit I, Urai I, and Urai II. The abration speed was 2-2,5 m/year. The other abration speed occurred in Air Petai, Palik, Pekik Nyaring in 0,5-1 m/year. On the other hand, Pasar Ketahun, Selolong, Air Serangai I, Air Serangai II, Kota Agung, Ulu Danau and Harapan was 1-2 m/year. The handling technique of all abration location of Jalinbar Bengkulu, north area using groin and jetty, except for Air Dikit and Urai I using jetty. Beside that, the handling technique for Air Serangai II using a combination of groin, jetty, and gabions.
Circuit Design for Sensor Detection Signal Conditioner Nitrate Content Manurung, Robeth Viktoria; Debataraja, Aminuddin; Hiskia, Hiskia
Makara Journal of Technology Vol. 15, No. 1
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Circuit Design for Sensor Detection Signal Conditioner Nitrate Content. Nitrate is one of macro nutrients very important for agriculture. The availability of nitrate in soil is limited because it is very easy to leaching by rain, therefore nitrate could be contaminated ground water by over-process of fertilizer. This process could also produce inefficiency in agriculture if it happened continuesly without pre-analysis of farm field. The answer those problems, it is need to develop the ion sensor system to measure concentrations of nitrat in soil. The system is consist of nitrate ion sensor device, signal conditioning and data acquisition circuit. The design and fabrications of signal conditioning circuit which integrated into ion nitrate sensor system and will apply for agriculture. This sensor has been used amperometric with three electrodes configuration: working, reference and auxiliarry; the ion senstive membrane has use conductive polymer. The screen printing technique has been choosen to fabricate electrodes and deposition technique for ion sensitive membrane is electropolymerization. The characterization of sensor has been conducted using nitrate standard solution with range of concentration between 1 μM–1 mM. The characterization has shown that sensor has a good response with cureent output between 2.8–4.71 μA, liniearity factor is 99.65% and time response 250 second.

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