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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 485 Documents
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Improving Renewable Energy Transition Acceptance: A Simulation Gaming Approach on a Multi Actor Setting in the Netherlands Sutrisno, Aziiz; Vennix, Jac A. M.; Syaifudin, Noor
Makara Journal of Technology Vol. 19, No. 3
Publisher : UI Scholars Hub

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Abstract

The Netherlands have tried very hard to increase their renewable energy sources (RES) shares to fulfill the European Union target in 2050. However, RES performance did not show the expected result as the performance declined in 2009 producing even wider gap compare to the target. The Dutch government’s tried to incorporate all interested stakeholders by forming the Dutch energy transition task force. Nevertheless, the task force’s result is also not showing a desirable trend. Key reasons behind the Dutch low RES performance are the lack of shared understanding and positive attitude toward RES development among interested actors. This research uses a role-playing game to increase shared understanding and positive attitude within the actors. The game set players in a competing role as the government, an energy company and the end user. Players were given the ability to make decisions on their respective area. A pilot study was then conducted to measure the effectiveness of the game. The pilot study showed the game increased actor’s individual understanding and shared understanding. Moreover, it also showed that the game increases actor’s positive attitude toward RES development in the Netherlands.
Calibration of Numerical Model for Shoreline Change Prediction Using Satellite Imagery Data Sutikno, Sigit; Murakami, Keisuke; Handoyo, Dwi Puspo; Fauzi, Manyuk
Makara Journal of Technology Vol. 19, No. 3
Publisher : UI Scholars Hub

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Abstract

This paper presents a method for calibration of numerical model for shoreline change prediction using satellite imagery data in muddy beach. Tanjung Motong beach, a muddy beach that is suffered high abrasion in Rangsang Island, Riau province, Indonesia was picked as study area. The primary numerical modeling tool used in this research was GENESIS (GENEralized Model for Simulating Shoreline change), which has been successfully applied in many case studies of shoreline change phenomena on a sandy beach.The model was calibrated using two extracted coastlines satellite imagery data, such as Landsat-5 TM and Landsat-8 OLI/TIRS. The extracted coastline data were analyzed by using DSAS (Digital Shoreline Analysis System) tool to get the rate of shoreline change from 1990 to 2014. The main purpose of the calibration process was to find out the appropriate value for K1 and K2 coefficients so that the predicted shoreline change had an acceptable correlation with the output of the satellite data processing. The result of this research showed that the shoreline change prediction had a good correlation with the historical evidence data in Tanjung Motong coast. It means that the GENESIS tool is not only applicable for shoreline prediction in sandy beach but also in muddy beach.
Uplift of Shoreline Regions on Pagai Island due to the September 12, 2007 Mw 8.4 Earthquake Captured by SAR Image Lubis, Ashar Muda
Makara Journal of Technology Vol. 19, No. 3
Publisher : UI Scholars Hub

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Abstract

At least 25 people were killed by the September 12, 2007 Mw 8.4 Bengkulu earthquake, and many buildings were destroyed in Bengkulu and West Sumatra provinces. It is very important to estimate the earth surface deformation due to the earthquake to understand the rupture size and its process. The aim of this research is to estimate the shoreline change and vertical displacement on Pagai Island associated with the September 12, 2007 Mw 8.4 Bengkulu earthquake. The intensity of ALOS-PALSAR satellite images is used to access the pattern of displacement. The result shows that Pagai Island demonstrated huge uplift due to the earthquake. In general, the result of uplift in the shoreline regions derived from Synthetic Aperture Radar (SAR) image has a good agreement with other methods, such as in situ measurements, InSAR, and Global Positioning System (GPS) observations. This result implies that the earthquake fault location was very close to/around Pagai Island. Using this method, we can easily estimate the pattern of deformation in very remote and very wide areas without any equipment on the ground. The only limitation is the method cannot provide quantitative displacement.
Effect of Fly Ash Fortification in the Manufacture Process of Making Concrete towards Characteristics of Concrete in Sulfuric Acid Solution Saputra, Asep Handaya; Shohibi, Muhammad; Kubouchi, Masatoshi
Makara Journal of Technology Vol. 19, No. 3
Publisher : UI Scholars Hub

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Abstract

Fly ash is a silica or alumino silica material that can be used as a constituent of cement in the concrete manufacturing process. Utilization of fly ash aims to improve durability and minimize the reduction of concrete’s compressive strength exposed to an acidic environment, which can be achieved through the pozzolanic reaction of fly ash with Ca(OH)2 within concrete. The reduced content of Ca(OH)2 through pozzolanic reaction will minimize the tendency of ettringite formation (compounds that cause deterioration and decrease the compressive strength of concrete). In order to determine the relation between fly ash replenishment into concrete with concrete’s characteristics (compressive strength and durability) under acidic environment, the research is conducted by varying the fly ash composition ranging from 0%, 5%, 25%, 50%, up to 75%, and the concentration of H2SO4 solution as an immersion medium ranging from 0%, 5%, 10%, up to 15% (v/v). The research is carried out by immersing the concrete samples for 4 days in H2SO4 solution with various concentrations. Characterization of concrete’s durability and compressive strength is reviewed from the concrete’s weight loss percentage and reduction of concrete’s compressive strength percentage after immersion. Based on the research results, for each variation of H2SO4 concentration used, the minimum concrete’s weight loss percentage (maximum durability) and the minimum reduction of concrete’s compressive strength percentage is found in the use of fly ash by 75%. For each concentration variations of H2SO4 solution as an immersion medium ranging from 5%, 10%, up to 15% (v/v), the minimum concrete’s weight loss percentage was 0.47%, 0.87%, 1.28% (respectively), whilst the minimum reduction of concrete’s compressive strength percentage was 5.71%, 14.29%, 17.14% (respectively). It was concluded that the use of fly ash can improve the durability and minimize the reduction of compressive strength of concrete exposed to an acidic environment.
Improvement of Quality of Carica papaya L. with Clove Oil as Preservative in Edible Coating Technology Kusrini, Eny; Usman, Anwar; Wisakanti, Chrispine Deksita; Arbianti, Rita; Nasution, Dedy Alharis
Makara Journal of Technology Vol. 19, No. 3
Publisher : UI Scholars Hub

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Abstract

We have studied utilization of essential clove oil, extracted from clove buds by hydrodistillation, as preservative in edible packaging technology. Preservative of essential clove oil was applied on chopped papaya fruits by using two methods, namely spray and brush. The effects of concentration of clove oil from 0.05 to 0.20% on the preservation of papaya fruits (Carica papaya L.) at room temperature (25 °C) were also evaluated. Physicochemical and in vitro microbiological activities on the papaya fruits that were stored at 25 oC and 85-90% relative humidity were investigated in details. The results indicate that the clove oil at concentration ≥0.10% suppressed the decay time, 10% weight loss, 0.03 g citric acid/100 g in acidity titration test, and 20% pH value from those of control sample of papaya fruits kept in a storage. The population of fungi and bacteria were efficiently reduced by 90% when the clove oil at concentration ≥0.10% was applied as preservative on papaya fruits. This finding suggested that the extracted essential clove oil acted as effective antifungal and antibacterial agents. Preservative by essential clove oil improved the quality of fruits to extend the product shelf life and to reduce the risk of microbial growth on fruits surface.
Dual-Band Singly-Fed Proximity-Coupled Tip-Truncated Triangular Patch Array for Land Vehicle Mobile System Basari, Basari; Sumantyo, Josaphat Tetuko Sri
Makara Journal of Technology Vol. 19, No. 3
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Abstract

This paper proposes a dual-band left-handed circularly polarized triangular-patch array that is developed for land vehicle mobile system aimed at mobile satellite communications. The array consists of six tip-truncated triangular patches, which the first three patches are used for reception and the second three patches are used for transmission purpose. Each of three-patches has a beam pattern that can be switched in three different 120°-coverage beam in azimuth-cut plane at a minimum targeted gain at a desired elevation angle. The targeted minimum gain of the array is 5 dBic, in order for data communications with a large geostationary satellite can be achieved. The array is able to operate in two different frequency bands i.e. 2.50 GHz band for reception (down-link) and 2.65 GHz band for transmission (uplink). The array is simulated using the Method of Moments-based software (Ansoft Maxwell), fabricated and measured to confirm the simulated results. The measurement results show that the 5dBic-gain and the 3dB-axial ratio of the reception elements cover all of 360° azimuth direction. In the case of transmission elements, 4.3dBic-gain and the 3dBaxial ratio can be obtained.
Residual Strength Analysisof Asymmetrically Damaged Ship Hull GirderUsing Beam Finite Element Method Alie, Muhammad Zubair Muis
Makara Journal of Technology Vol. 20, No. 1
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Abstract

The objective of the present study is to analyze the residual strength of asymmetrically damaged ship hull girder under longitudinal bending. Beam Finite Element Method is used for the assessment of the residual strength of two single hull bulk carriers (Ship B1 and Ship B4) and a three-cargo-hold model of a single-side Panamax Bulk Carrier in hogging and sagging conditions. The Smith’s method is adopted and implemented into Beam Finite Element Method. An efficient solution procedure is applied; i.e. by assuming the cross section remains plane, the vertical bending moment is applied to the cross section and three-cargo-hold model. As a fundamental case, the damage is simply created by removing the elements from the cross section, neglecting any welding residual stress and initial imperfection. Also no crack extension is considered. The result obtained by Beam Finite Element Method so-called Beam-HULLST is compared to the progressive collapse analysis obtained by HULLST for the validation of the present work. Then, for the three-hold-model, the Beam-HULLST is used to investigate the effect of the rotation of the netral axis both intact and damage condition taking the one and five frame spaces into account.
Multi-Project Scheduling Cost Optimization in a Machine Manufacturer Engineer-to-Order Farizal, Farizal; Rachman, Amar; Tandean, Tifani; Sudarto, Sumarsono; Takahashi, Katsuhiko
Makara Journal of Technology Vol. 20, No. 1
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Abstract

This paper discusses the utilization of mixed integer linear programming (MILP) model to optimize cost for multiproject scheduling in a machine maker company. The objective is to minimize total project’s penalty cost and labor cost. The model formulated shows how to achieve the objective i.e. whether to use outsourcing or overtime to finish all projects. The model of multi-project scheduling was solved by Branch & Bound algorithm coded in Lingo 14.0 software. The case study shows that if a company wants to minimize lateness, it should use overtime instead of outsourcing, which minimize total lateness of projects by 144 days or 73.5%. Whereas, if a company wants to optimize cost, they should use outsourcing instead of overtime, which reduces total cost of about 10,873,000 IDR or 28.5%. These results indicate that the model developed is applicable for optimizing multi-project scheduling.
Thermal Properties, Crystallinity, and Oxygen Permeability of Na-montmorillonite Reinforced Plasticized Poly(lactic acid) Film Yuniarto, Kurniawan; Purwanto, Yohanes Aris; Purwanto, Setyo; Welt, Bruce A.; Purwadaria, Hadi Karia; Sunarti, Titi Candra
Makara Journal of Technology Vol. 20, No. 1
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Abstract

Introducing unmodified organically clay/Na-montmorillonite (Na-MMT) was applied into plasticized poly(lactic acid) PLA to produce film composites by direct casting. Film composite structure, the crystallinity degree and form, and thermal properties were carried out using X-ray diffraction and differential scanning calorimetry. The effect of Na- MMT to the tortuous path and the crystallinity degree in the plasticized film composites were calculated in oxygen barrier properties. Chromatogram film composites resulted in an intercalated structure that showed peak diffraction angle shift at about 0.2o. Then, a peak diffraction pattern was indicated in α-form crystal structure. Plasticized PLA has a crystallinity degree at 34%, and the addition of Na-MMT increased to 52%. Glass transition temperature improved from 53 °C to 57 °C, and melting temperature remained stable at 167 °C. Filling Na-MMT into plasticized PLA caused to enhance a tortuous path about 28% and improved the oxygen permeability to 80%. As a result, the addition of Na- MMT of 3% into plasticized PLA during film composite preparation using the mixing method resulted in balancing properties related to the crystallinity degree, thermal properties, and oxygen barrier properties.
Maneuverability of Ships with small Draught in Steady Wind Paroka, Daeng; Muhammad, Andi Haris; Asri, Syamsul
Makara Journal of Technology Vol. 20, No. 1
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Abstract

Wind force and moment may force a ship to drastically decrease its speed and use a large drift angle as well as a large rudder angle in order to maintain its course. Ships with a small draught might have more risk in maneuvering to its point of view compared with a ship with a larger draught. This paper discusses maneuverability of a ship with a small draught in steady wind. The effect of wind on ship speed, drift angle, and rudder angle are investigated in a steady state condition. Five different ratios of wind velocity to ship speed from 1.0 to 20.0 are used in the simulation. The variation in wind direction is examined from 0° to 180°. Results of the numerical simulation show that the wind has a significant effect on the reduction in ship speed with a wind direction less than 100°. The drift angle increases due to increasing wind velocity in the same wind direction. Wind direction also has a significant effect on the drift angle especially when the wind direction is less than 140°. The same phenomenon was found for the rudder angle. The necessary rudder angle is greater than the maximum rudder angle of the ship when the wind direction is 60° with a wind velocity to ship speed ratio of 20 or more.

Page 30 of 49 | Total Record : 485

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