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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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Development of Fiber-Optic Humidity Sensor Probe with Gelatin Cladding Maddu, Akhiruddin; Modjahidin, Kun; Sardy, Sar; Zain, Hamdani
Makara Journal of Technology Vol. 10, No. 1
Publisher : UI Scholars Hub

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Abstract

Development of Fiber-Optic Humidity Sensor Probe with Gelatin Cladding. Humidity sensor based on optical fiber with gelatin cladding has been developed. In this humidity sensor probe, the origin cladding of optical fiber is replaced by gelatin coating as humidity sensitive cladding. Testing of the optical fiber sensor probe was conducted by measuring of light intensity transmitted on the optical fiber probe for each variation of different humidity treatments. Response of the optical fiber sensor probe measured from 42%RH to 99%RH, the results show an optical transmission curve varied with relative humidity (RH). Optical transmission in the optical fiber probe increase with RH value at a specific wavelength range, that is from green to red spectrum bands (500 nm – 700 nm), where a significant variation from 600 nm to 650 nm in yellow to red spectrum bands. Wavelength where is a maximum intensity of optical transmission occurs at 610 nm. Therefore, the optical fiber humidity sensor probe could response humidity form 42%RH to 99%RH with the best response in humidity range of 60%RH to 72%RH that is have a good linearity and sensitivity.
Production of Medium Chain Length Polyhydroxyalkanoates From Oleic Acid Using Pseudomonas putida PGA1 by Fed Batch Culture Marsudi, Sidik; Tan, Irene K.P.; Gan, Seng Neon; Ramachandran, K. B.
Makara Journal of Technology Vol. 11, No. 1
Publisher : UI Scholars Hub

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Abstract

Bacterial polyhydroxyalkanoates (PHAs) are a class of polymers currently receiving much attention because of their potential as renewable and biodegradable plastics. A wide variety of bacteria has been reported to produce PHAs including Pseudomonas strains. These strains are known as versatile medium chain length PHAs (PHAs-mcl) producers using fatty acids as carbon source. Oleic acid was used to produce PHAs-mcl using Pseudomonas putida PGA 1 by continuous feeding of both nitrogen and carbon source, in a fed batch culture. During cell growth, PHAs also accumulated, indicating that PHA production in this organism is growth associated. Residual cell increased until the nitrogen source was depleted. At the end of fermentation, final cell concentration, PHA content, and productivity were 30.2 g/L, 44.8 % of cell dry weight, and 0.188 g/l/h, respectively.
Biodesulphurization Within Natural Gas in Oil and Gas Field Rahayu, Sri Astuti; Fierdaus, M.; Syafrizal, Syafrizal; Udiharto, M.
Makara Journal of Technology Vol. 11, No. 1
Publisher : UI Scholars Hub

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Abstract

The presence of sulphur compounds in natural gas can interfere to the quality of natural gas. The decline of combustion gas capacity, metal instrument corrosion in gas piping, and the environmental pollution from gas emission can affect by their presence. Bio-filter is one of the methods that selected to reduce sulphur content in natural gas. A lab scale study of hydrogen sulphide reduction in natural gas had conducted in oil and gas field using bio-filter method. The bio-filter system (±1 L volume) contains an active carbon and thiosulphide medium as a substrate, Thiobacillus thioparus as a single culture of sulphur bacteria, and Thiobacillus thioparus with sludge as a mixed culture of sulphur bacteria. The study of hydrogen sulphide reduction was conducted with continuous flow line process. The gas flow rate approximately 1.5 L/min with a fluctuate presence of Hydrogen sulphide (approximately 40 – 70 mg/L). The bio-filter system contains active carbon, thiosulphide medium, and single culture of T. thioparus appear as a good filter for hydrogen sulphide reduction. During 24 hours, the hydrogen sulphide reduction obtains 93% to 16%. When culture media added, the hydrogen sulphide reduction will increase almost 60% and then the reduction decrease to 4% after 20 hours. It is concluded that the bio-filter have potential to develop for sulphur reduction in natural gas.
SIMPLE: System Automatic Essay Assessment for Indonesian Language Subject Examination Ratna, Anak Agung Putri; Budiardjo, Bagio; Hartanto, Djoko
Makara Journal of Technology Vol. 11, No. 1
Publisher : UI Scholars Hub

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Abstract

SIMPLE: System Automatic Essay Assessment for Indonesian Language Subject Examination. Evaluation of study of a student is a very important aspect of an educational process. Evaluation is aimed at measuring the level of student understanding of the given lecture materials. Measuring student understanding of the course material, using essay-type exam, is generally used as the evaluation tool. In this essay-type exam, the student has to answer questions using sentences, whereby choices of possible answers are not indicated. The student has to answer the questions with his/her sentences. The answers may vary, since it reflects the student’s best thoughts of the materials. One of the weaknesses of essay-type exam is the difficulty to grade the answers and it tends to be time consuming. Currently, automatic grading systems that may speed up the grading process, are being developed in many research institutions. The method used to grade, varies form one system to another, and one of the popular system is the Latent Semantic Analysis (LSA). LSA is a method of grading essay by extracting words and representing the sentence in the form of mathematical or statistical formulation, from a text with a relatively large number of words. The grade of the essay is determined, by matching the important words to a group of words prepared by the human rater. This paper describes an effort to developed LSA, enhanced with word weighting, word order and the word synonym to improve the accuracy of grading. This system is called SIMPLE. SIMPLE is used to grade answers using bahasa Indonesia. The exam is carried out on-line through the Web. From the experiments conducted, for small classes, the conformity of grade compared to the grade of human rater lies between 69.80 % – 94.64 %, and for medium size classes the conformity lies between 77.18 % - 98.42 % with the human rater. These results are roughly proportional with the result of LSA system, which grade essay given in English.
Utilization of Bagasse Cellulose for Ethanol Production through Simultaneous Saccharification and Fermentation by Xylanase Samsuri, M.; Gozan, Misri; Mardias, R.; Baiquni, M.; Hermansyah, Heri; Wijanarko, Anondho; Prasetya, Bambang; Nasikin, M.
Makara Journal of Technology Vol. 11, No. 1
Publisher : UI Scholars Hub

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Abstract

Utilization of Bagasse Cellulose for Ethanol Production through Simultaneous Saccharification and Fermentation by Xylanase. Bagasse is a solid residue from sugar cane process, which is not many use it for some product which have more added value. Bagasse, which is a lignosellulosic material, be able to be use for alternative energy resources like bioethanol or biogas. With renewable energy resources a crisis of energy in Republic of Indonesia could be solved, especially in oil and gas. This research has done the conversion of bagasse to bioethanol with xylanase enzyme. The result show that bagasse contains of 52,7% cellulose, 20% hemicelluloses, and 24,2% lignin. Xylanase enzyme and Saccharomyces cerevisiae was used to hydrolyse and fermentation in SSF process. Variation in this research use pH (4, 4,5, and 5), for increasing ethanol quantity, SSF process was done by added chloride acid (HCl) with concentration 0.5% and 1% (v/v) and also pre-treatment with white rot fungi such as Lentinus edodes (L.edodes) as long 4 weeks. The SSF process was done with 24, 48, 72, and 96 hour’s incubation time for fermentation. Variation of pH 4, 4,5, and 5 can produce ethanol with concentrations 2,357 g/L, 2,451 g/L, 2,709 g/L. The added chloride acid (HCl) with concentration 0.5% and 1% (v/v) and L. edodes can increase ethanol yield, The highest ethanol concentration with added chloride acid (HCl) concentration 0.5% and 1% consecutively is 2,967 g/L, 3,249 g/L. The highest ethanol concentration with pre-treatment by L. edodes is 3,202 g/L.
Construction of Short-Length High-Rates LDPC Codes Using Difference Families Hamdani, Deny; Safrianti, Ery
Makara Journal of Technology Vol. 11, No. 1
Publisher : UI Scholars Hub

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Abstract

Low-density parity-check (LDPC) code is linear-block error-correcting code defined by sparse parity-check matrix. It is decoded using the massage-passing algorithm, and in many cases, capable of outperforming turbo code. This paper presents a class of low-density parity-check (LDPC) codes showing good performance with low encoding complexity. The code is constructed using difference families from combinatorial design. The resulting code, which is designed to have short code length and high code rate, can be encoded with low complexity due to its quasi-cyclic structure, and performs well when it is iteratively decoded with the sum-product algorithm. These properties of LDPC code are quite suitable for applications in future wireless local area network.
Kinetic Model For Triglyceride Hydrolysis Using Lipase:Review Hermansyah, Heri; Wijanarko, A.; Dianursanti, Dianursanti; Gozan, Misri; Wulan, Praswasti P. D.K; Arbianti, Rita; Soemantojo, Roekmijati W.; Utami, Tania Surya; Yuliusman, Yuliusman; Kubo, Momoji; Kitakawa, Naomi Shibasaki; Yonemoto, Toshiy
Makara Journal of Technology Vol. 11, No. 1
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Abstract

Triglyceride hydrolysis using lipase has been proposed as a novel method to produce raw materials in food and cosmetic industries such as diacylglycerol, monoacylglycerol, glycerol and fatty acid. In order to design a reactor for utilizing this reaction on industrial scale, constructing a kinetic model is important. Since the substrates are oil and water, the hydrolysis takes place at oil-water interface. Furthermore, the triglyceride has three ester bonds, so that the hydrolysis stepwise proceeds. Thus, the reaction mechanism is very complicated. The difference between the interfacial and bulk concentrations of the enzyme, substrates and products, and the interfacial enzymatic reaction mechanism should be considered in the model.
Sulfonation of cPTFE Film grafted Styrene for Proton Exchange Membrane Fuel Cell Yohan, Yohan
Makara Journal of Technology Vol. 11, No. 1
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Sulfonation of cPTFE Film grafted Styrene for Proton Exchange Membrane Fuel Cell. Sulfonation of γ-ray iradiated and styrene-grafted crosslinked polytetrafluoroethylene film (cPTFE-g-S film) have been done. The aim of the research is to make hydropyl membrane as proton exchange membrane fuel cell. Sulfonation was prepared with chlorosulfonic acid in chloroethane under various conditions. The impact of the percent of grafting, the concentration of chlorosulfonic acid, the reaction time,and the reaction temperature on the properties of sulfonated film is examinated. The results show that sulfonation of surface-grafted films is incomplete at room temperature. The increasing of concentration of chlorosulfonic acid and reaction temperature accelerates the reaction but they also add favor side reactions. These will lead to decreasing of the ion-exchange capacity, water uptake, and proton conductivity but increasing the resistance to oxidation in a perhidrol solution. The cPTFE-g-SS membrane which is resulted has stability in a H2O2 30% solution for 20 hours.
Mechanical Study on using of ACCR Thermal Conductor at 500 kV SUTET Prasetyono, Suprihadi
Makara Journal of Technology Vol. 11, No. 1
Publisher : UI Scholars Hub

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Abstract

Mechanical Study on using of ACCR Thermal Conductor at 500 kV SUTET. At the height of electricity demand increasing recently, circumstance of environment more limited and also expense of high investment, making thermal conductor (conductor thermal resistance) considered to be one of alternative in the electricity transmission bottlenecks. These days it has been developed thermal conductor ACCR (Aluminium Conductor Composite Reinforced) which can operate with temperature up to 240oC, so that making the current carrying capacity being higher than conventional conductor. This research aimed to study load current leading to mechanical characteristic ACCR conductor included tension, length of elongation and sag of conductor. Its expected to be good for develop in construction structure of transmission line which is appropriate to ACCR conductor characteristic. Based on this research it can be concluded that application of ACCR conductor improves transmission line capacities by 100 % on existing ROW and tower.
Segmental Sinusoidal Model for Speech Signal Coding Setiawan, Florentinus Budi; Soegijoko, Soegijardjo; Sugihartono, Sugihartono; Tjondronegoro, Suhartono
Makara Journal of Technology Vol. 10, No. 2
Publisher : UI Scholars Hub

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Abstract

Segmental Sinusoidal Model for Speech Signal Coding. Periodic signal can be decomposed by sinusoidal component with Fourier series. With this characteristic, it can be modeled referring by sinusoidal form. By the sinusoidal model, signal can be quantized in order to encode the speech signal at the lower rate. The recent sinusoidal method is implemented in speech coding. By using this method, a block of the speech signal with 20 ms to 30 ms width is coded based on Fourier series coefficients. The new method proposed is quantization and reconstruction of speech signal by the segmental sinusoidal model. A segment is defined as a block of the speech signal from certain peak to consecutive peak. The length of the segment is variable, instead of the fixed block like the recent sinusoidal method. Coder consists of the encoder and the decoder. Encoder works to code speech signal at variable rate. Then coded signal will be transmitted to receiver. On the receiver, coded signal will be reconstructed, so that the reconstruction signal has the near quality compared with the original signal. The experimental results show that the average of segmental SNR is more than 20 dB.

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