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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 7 Documents
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Search results for , issue "Vol. 24, No. 1" : 7 Documents clear
Effects of Collision Damage on the Ultimate Strength of FPSO Vessels Alie, Muhammad Zubair Muis; Ramasari, Dian; Rachman, Taufiqur; Adiputra, Ristiyanto
Makara Journal of Technology Vol. 24, No. 1
Publisher : UI Scholars Hub

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Abstract

Floating production storage offloading (FPSO) vessels are movable offshore structures. These structures are designed with large dimensions, and their decks are loaded with several types of equipment. During collision damage, the hull and deck parts loaded with equipment are severely affected. Therefore, the ultimate strength of FPSO vessels should be thoroughly checked and evaluated. The objective of the present study is to analyze the ultimate strength of FPSO vessels against collision damage characterized by hogging and sagging under longitudinal bending. The cross section of an FPSO vessel is modeled with elements composed of stiffened and unstiffened plates. The vessel length is assumed to occupy one frame space. The ultimate strength of FPSO vessels against collision damage is determined by performing a numerical analysis under hogging and sagging conditions. Multipoint constraint is applied to both sides of the cross section, and the material properties are set to be constant. Collision damage is represented by the loss of element stiffness, and it represents the percentage of the ship’s depth. For the extent of transversal damage, B/16 is set to be constant. The minimum and maximum collision damages are taken as 10% and 60% of the ship’s depth, respectively. Numerical results show that the ultimate strength of FPSO vessels and their bending stiffness decrease under collision.
Ionic Conductivity and Electrochemical Properties of Alginate–NN4NO3-Based Biopolymer Electrolytes for EDLC Application Mazuki, Norfatihah binti; Rasali, Nur Muhitul Jalilah; Sahraoui, Bouchta; Samsudin, Ahmad Salihin
Makara Journal of Technology Vol. 24, No. 1
Publisher : UI Scholars Hub

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Abstract

In this work, alginate doped with various contents of ammonium nitrate (NH4NO3) as a solid biopolymer electrolyte (SBE) was prepared via casting by using distilled water as a solvent. Impedance studies on alginate–NH4NO3 SBE films were conducted via impedance spectroscopy. The lowest bulk resistance (Rb) showed that the maximum ionic conductivity of the sample containing 25 wt.% NH4NO3 at ambient temperature (303 K) was 5.56 × 10−5 S cm−1. The temperature dependence of ionic conductivity was evaluated, and results confirmed that electrolytes followed an Arrhenius behavior. The highest conducting sample was fabricated into an electrical double-layer capacitor and characterized in terms of its electrochemical properties through cyclic voltammetry (CV) and galvanostatic charge–discharge (GCD) measurement. CV analysis indicated that specific capacitance decreased as the scan rate increased. Conversely, GCD analysis showed that specific capacitance almost remained unchanged for up to 5000 cycles.
Ethylene Carbonate and Polyethylene Glycol as Efficient Plasticizers in CMC-PVA-NH4NO3-Based Polymer Electrolyte Mohd Ali, Noor Saadiah; Nagao, Yuki; Samsudin, Ahmad Salihin
Makara Journal of Technology Vol. 24, No. 1
Publisher : UI Scholars Hub

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Abstract

This study investigated the influence of plasticizers (polyethylene glycol [PEG] and ethylene carbonate [EC]) on the ionic conduction of CMC-PVA-NH4NO3. Blended biopolymer electrolytes (BBEs) based on carboxymethyl cellulose–polyvinyl alcohol (CMC-PVA) doped with ammonium nitrate (NH4NO3) were obtained via casting solution technique incorporated with PEG and EC, which acted as plasticizers. Electrical impedance spectroscopy (EIS) was conducted to evaluate the effect of plasticization on the ionic conduction properties. The ionic conductivity improved from 1.70 × 10−3 S/cm for un-plasticized BBEs to 3.92 × 10−3 S/cm for plasticized BBEs with EC and 3.00 × 10−3 S/cm for plasticized BBEs with PEG. The improvement indicated that the plasticizers weakened the Coulombic force and promoted further dissociation in the ionic dopant. The highest ionic conductivity was achieved for BBEs plasticized with EC, thereby suggesting the suitability of EC as plasticizer in this present system. The BBE system showed the Arrhenius characteristic at elevated temperatures and demonstrated increasing ionic conductivity. Dielectric properties of all BBE systems were found to improve upon the addition of EC and PEG, demonstrating their correlation with ionic conductivity.
Synthesis of Epoxy Monoethanolamide from Bauhinia monandra Seed Oil Adewuyi, Adewale; Oderinde, Rotimi A.
Makara Journal of Technology Vol. 24, No. 1
Publisher : UI Scholars Hub

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Abstract

In this study, we synthesized epoxidised monoethanolamide (EMA) from Bauhinia monandra seed oil (BMO) via a simple reaction route. In this process, BMO was transesterified to obtain a mixture of methyl esters, which was subjected to a urea adduct complexation reaction. The unsaturated methyl esters (BME) from the urea adduct complexation reaction were then epoxidised using performic acid produced in situ in a one-pot reaction system. The epoxidised methyl esters were converted to EMA by reacting them with monoethanolamine (1:10). The progression of the reaction was monitored using Fourier transform infrared spectroscopy and proton nuclear magnetic resonance spectroscopy, and the fatty acid composition was determined by gas chromatography. The results indicate that the most abundant fatty acid in BMO is C18:1 (25.70% ± 0.20%), with a degree of unsaturation of 49.00% ± 0.50%. After the urea adduct complexation reaction, the degree of unsaturation increased to 95.20% ± 0.10% with C18:2 (75.00% ± 0.10%) becoming the most dominant fatty acid. The oxirane oxygen content was found to be 5.50% ± 0.50%. The results of this study suggest that the urea adduct complexation reaction offers a potential means for increasing the unsaturation of fatty methyl esters. In addition, our findings show that EMA can be produced at low or room temperature.
Liquefaction Potential Analysis Based on Nonlinear Ground Response on the Coastline of Bengkulu City, Indonesia Mase, Lindung Zalbuin
Makara Journal of Technology Vol. 24, No. 1
Publisher : UI Scholars Hub

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Abstract

This paper presents the study of the seismic response and liquefaction potential of the coastal area of Bengkulu City during the September 2007 Sumatra earthquake. The study is conducted by collecting site investigation data (standard penetration test) and applying input motion to observe soil response. Synthetic ground motion is generated by considering the important aspects of earthquakes, including focal depth, epicenter, earthquake source, and site classification. The synthetized ground motion is then used as the input motion in the seismic response analysis. The results of this analysis are spectral acceleration and peak ground acceleration at each depth. The resulting spectral acceleration is compared with that specified in the seismic design code of Indonesia (SNI 03-1726-2012). Liquefaction potential analysis is performed on the basis of the results of the seismic response analysis. Results show that spectral acceleration depends on soil type. A high soil density equates to a low spectral response. The designed spectral acceleration may still be considered for each borehole, especially for T (period) < 1. However, for T > 1, spectral acceleration should be prioritized, especially for high-rise building construction. The liquefaction analysis reveals that a shallow depth is vulnerable to liquefaction. In general, this study could give a better understanding on the implementation of seismic ground response for liquefaction potential analysis.
Current Status of Hydrothermal Treatment for Energy and Material Recovery Toward a Sustainable Post-consumer Material Cycle Lokahita, Baskoro; Aziz, Muhammad; Takahashi, Fumitake
Makara Journal of Technology Vol. 24, No. 1
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Abstract

The demand for energy-efficient and environmentally friendly municipal solid waste (MSW) processing has increased in developing countries. The thermochemical process offers a fast and reliable solution to reutilize or reduce the volume of MSW. Hydrothermal treatment is a novel MSW treatment technology that is compatible with high-moisture-content feedstock. It involves the thermal degradation of MSW in pressurized water or steam, which promotes the disintegration of cellulosic and polymer materials. Recent advances have shown effective MSW conversion into homogenous solid hydrochar with higher energy density. Alkali and chlorine content, which causes issues in combustors, was successfully removed due to the washing effect of hydrothermal treatment. The possibility of activated carbon production also exists because the surface area is significantly increased after the treatment. This paper presents an overview of the latest development of hydrothermal treatment in the field of post-consumer waste and MSW treatment, with particular focus on the operating conditions and physicochemical characteristics of the hydrochar. Several experimental results from post-consumer waste feedstock were compiled and interpreted using principal component analysis to observe the effect of different operating conditions and feedstock during the hydrothermal process.
Comparison of Phytoremediation and Filtration for Diamond-mine-tailings Water Treatment Noor, M. Hafidhuddin; Rahman, Mijani; Gazali, Akhmad; Kania, Nia; Rahma, Aulia; Rampun, Erdina L.A.; Pratiwi, Amalia E.; Elma, Muthia
Makara Journal of Technology Vol. 24, No. 1
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Abstract

The water pollution caused by diamond mine activities can kill aquatic life. In this work, we used phytoremediation and filtration to treat pond water polluted by the tailings of a diamond mine located in South Kalimantan, Indonesia. Einchhornia crassipes (water hyacinth) was utilized as the biomass for the phytoremediation process. Gravel (10–15 mm) and sand (0.1–1 mm) were used as filter media in the simple filtration setup, using an up-flow system (bottom to top). In the experiment, 16 L of diamond tailing water was poured into five phytoremediation reactors (each 60 L in volume), which were then tested over seven days. A pretreatment analysis of the tailings water showed that its biochemical oxygen demand (BOD) of 8.9 mg L−1 and chemical oxygen demand (COD) of 22 mg L−1 exceeded the national maximum standards of 2 mg L−1 and 10 mg L−1, respectively. The experimental results demonstrate that both phytoremediation and filtration could increase the dissolved oxygen concentration (4.7 mg.L−1) and reduce the BOD (3.2 mg.L−1), COD (6.5 mg.L−1), Fe (0.6 mg.L−1), Mn (0.16 mg.L−1), and ammonia (0.63 mg.L−1) concentrations from those measured in the raw diamond-mine-tailings water. The phytoremediation performance was better than that of filtration. The COD values were successfully reduced to the permissible limit, although the other parameters still failed to meet the government water quality regulation requirements.

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