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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 439 Documents
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Improvement of Electrical Properties of CMC-PVA Doped with Various Contents of LiNO3 as an Application for Hybrid Polymer Electrolytes Zulkifli, Amalia; Mazuki, Norfatihah; Samsudin, Ahmad Salihin
Makara Journal of Technology Vol. 25, No. 2
Publisher : UI Scholars Hub

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Abstract

The present work was carried out with the development of hybrid polymer electrolytes (HPEs) by using carboxymethyl cellulose (CMC)–polyvinyl alcohol (PVA) doped with different contents of lithium nitrate (LiNO3) for the determination of their structural and conduction properties. The structural analysis was conducted by using Fourier transform infra-red spectroscopy and showed the interaction between the blend host polymer and ionic dopant, which formed via the coordinating site of CMC-PVA and Li+-NO3−. The complexes of CMC-PVA doped LiNO3 led to an increment in ionic conductivity, as observed by electrical impedance spectroscopy, and the sample containing 20 wt% LiNO3 obtained the highest ionic conductivity of 3.54 × 10−3 S cm−1 at room temperature. The ionic conductivity at different temperatures (from 303 K to 343 K) was measured and found to obey the Arrhenius rule. The activation energies of the HPEs were computed based on the Arrhenius equation and were inversely proportional to the ionic conductivity. The highest ionic conducting sample was fabricated into an electrical double layer capacitor (EDLC). Cyclic voltammetry (CV) was used to study the electrochemical performance of the EDLC. A high value of Cs was obtained at 2 mVs−1 due to the utilization of ions in the vacant sites of the electrode material.
Comparison of Concrete and Steel Jacket Methods for Reinforcing A Concrete Bridge Pier by Numerical and Experimental Studies Faghihmaleki, Hadi
Makara Journal of Technology Vol. 25, No. 2
Publisher : UI Scholars Hub

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Abstract

Various rehabilitation and strengthening procedures have been developed in recent decades. A study to determine which methods can be implemented to increase the useful life of the bridge before strengthening must be performed. In this study, the seismic behavior of a reinforced concrete bridge pier with dimension 3.5 × 3.5 m, which was reinforced by two steel and a concrete jacket, was investigated. Nonlinear geometric models and materials were analyzed to estimate the seismic parameters of the pier. Results show an increase in energy absorption, ultimate strength, and ductility for the steel jacket, as well as a greater increase in the concrete jacket. Using a box concrete jacket with a dimension of 3.5 × 3.5 m, the increase in percentages of energy absorption, ultimate strength, and ductility were 38, 14, and 13, respectively. Therefore, the concrete jacket enhances the mentioned parameters.
Effect of Arc Plasma Sintering on the Structural and Microstructural Properties of Fe-Cr-Ni Austenitic Stainless Steels Parikin, Parikin; Dani, M.; Dimyati, A.; Purnamasari, N. D.; Sugeng, B.; Panitra, M.; Insani, A.; Priyanto, T. H.; Mustofa, S.; Syahbuddin, Syahbuddin; Huang, A.
Makara Journal of Technology Vol. 25, No. 2
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Abstract

X-ray diffraction techniques were performed to determine the actual crystal structure of A2 austenitic stainless steel (ASS) as-cast and A2 ASS after arc plasma sintering (APS) for 2 s. Computations were conducted on the basis of the Bragg arithmetic formula by comparing the S2 arithmetic with the interplanar spacing. The Bragg arithmetic formula is a simple series for the determination of the crystalline phase of materials based on the Miller indices of cubic shapes or other shapes. A2 ASS as-cast was identified to have a crystal structure of face-centered cubic with lattice parameter a = 3.58 Å. A similar crystal structure can still be detected in A2 ASS after APS for 2 s with lattice parameter a = 3.60 Å. This finding was confirmed by neutron diffraction measurements and optical–electron microscopy observations. Under the same conditions, both A2 ASS as-cast and A2 ASS after APS for 2 s have similar cast structures. The grain boundary formed in A2 ASS as-cast is thinner than that in A2 ASS after APS for 2 s, which is visible in its boundaries. Moreover, the grain structure of A2 ASS after APS for 2 s, which was originally elongated particles, became globular particles. Similarly, granular precipitates became concentrated and encompassed the steel matrix along the grain boundaries. Furthermore, scanning electron microscopy with energy-dispersive X-ray analysis showed that particles and islands in steel are distributed in the grains and at the grain boundaries, respectively. Precipitates are composed of C, Cr, Fe, and Ni. The elemental contents of Cr and C are dominant; thus, Cr23C6 precipitate is formed at the grain boundaries.
Trend Significance Levels of Rain Onset and Cessation and Lengths of the Wet and Dry Seasons in Epe, Lagos State, Nigeria Alli, Adekunle Adedeji; Omofunmi, Olorunwa Eric
Makara Journal of Technology Vol. 25, No. 2
Publisher : UI Scholars Hub

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Abstract

This study aims to reduce crop failure resulting from a dry spell, which is the first occurrence of unsustainable rainfall that deceives farmers into planting. Thus, trends need to be tested using hypothesis, kurtosis, and other statistics to analyze the risks associated with unstable planting calendars and their possible mitigation strategies. The daily rainfall data from 1982 to 2018 were obtained from the archive of NASA/POWER SRB/FLASH, and the research location is Epe, Lagos State, Nigeria, which lies at latitude 6.585° N and longitude 3.962° E. Microsoft Excel was used to perform the tests. Results show that the null hypothesis of no trend in the distribution was rejected on the basis of the fact that the probability value (p = 0.00) is less than the significance level (α = 0.05). The mean onset and cessation dates are March 27 and October 18, with skewness values of −0.63 and 11.02, respectively. Rain onset and cessation that occur from February 12 to April 27 and from September 28 to November 28, respectively, are safe with low risks of dry spell. Moreover, drought and dry spell were most probable in years that experienced a shorter length of wet season than dry season.
Music Information Retrieval Based on Active Frequency Wibowo, Hardianto; Suharso, Wildan; Azhar, Yufis; Wicaksono, Galih Wasis; Minarno, Agus Eko; Harmanto, Dani
Makara Journal of Technology Vol. 25, No. 2
Publisher : UI Scholars Hub

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Abstract

Music is the art of combining frequencies. A balance of frequencies gives rise to a harmonious tone. Several features of music can be analyzed, and they include sociocultural background, lyrics, mood, tempo, rhythm, harmony, melody, timbre, and instrumentation. In this study, we use the frequency of instrumentation as a feature for classification because each instrument has a frequency range. To test this frequency range, we use five music genres and one music playing skill. The five genres are dangdut, electronic dance music (EDM), metal, pop/rock, and reggae. The music playing skill is acoustic. Active frequencies are tested using the k-nearest neighbor method, and the results serve as basis of the accuracy of music classification. The classification accuracy for EDM, metal, and acoustic is over 70%, whereas that for dangdut, pop/rock, and reggae is less than 60%. In sum, the accuracy of music classification is influenced by the similarities in the music instruments used and the tempo.
Kinetic Modeling Study of Laminar Burning Velocity of Gasoline–Ethanol–Methanol Blends at Elevated Temperature and Pressure Auzani, Ahmad Syihan; Wibowo, Cahyo Setyo; Anggarani, Riesta; Nugroho, Yulianto Sulistyo; Sugiarto, Bambang
Makara Journal of Technology Vol. 25, No. 2
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Abstract

Gasoline–ethanol–methanol (GEM) blends have been considered to replace pure gasoline as spark ignition engine fuel. Their physical and chemical properties and performance and emission measurements from real engines have been reported previously. However, a fundamental study that can explain the unique results of GEM compared with those of pure gasoline is lacking. This study aims to compare the laminar burning velocity of GEM blends at different mixtures, equivalence ratios, temperatures, and pressures with that of pure gasoline. A laminar flame propagation model and reaction mechanisms from the literature were were for a numerical simulation. In this study, the chemical components of real gasoline are simplified using a binary surrogate mixture. Results show that the laminar burning velocity of the GEM increased with the increase in temperature, ethanol, and methanol concentration, and it decreased with the increase in pressure. Sensitive reactions to laminar burning velocity are presented through a sensitivity analysis.
Predictive Delivery Man Assignment Problem using Deep Learning Juarsa, Rahmadini Payla; Djatna, Taufik
Makara Journal of Technology Vol. 25, No. 2
Publisher : UI Scholars Hub

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Abstract

Dispatching is a critical part in current online shopping. It relates to how the delivery man assignment should minimize cost along with the service from a source to an end customer with an appropriate scheduled time. The problem arises as neither enough products to deliver nor delivery men are available for dispatch, resulting in suboptimal service and a waste of money. The study aimed to formulate the cost of restaurant dispatching for inducing a deep learning-based solution with the gated recurrent unit recurrent neural network to receive hourly order data and to engage the result for near feature delivery man schedule with minimum cost. The result showed that cost formulation minimized the number of delivery men times the wage per hour with the constraints of each delivery man carrying a maximum of five orders in one way and 11 work hours/day. The deep learning input model used 1078 historical data which were filtered using the Savitzky-Golay method. The root mean square errors of training and testing were 2.35 and 2.41, respectively. Moreover, the number of delivery men every hour was found in a range from one to four people. Furthermore, the deep learning approach saved costs of up to 43.8%.
Effects Of 0.25 % Mo (Molybdenum) Which Is Contained In The Ductile Cast Iron On Mechanical Properties Of Austempered Ductile Iron (ADI). Nukman, Nukman; Arifin, Bustanul; Sugiarto, Bambang
Makara Journal of Technology Vol. 6, No. 1
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Abstract

The aim of this research is to investigate the effects of 0.25 % Mo (Molybdenum) which is contained in the ductile cast iron on mechanical properties of Austempered Ductile Iron (ADI). The various temperatures and the holding times are used in the heat treatment processes. Using a given 0.25 % Mo in the ductile iron, ADI's alloyed developes a higher ultimate tensile stress value and decreases the elongation if we compare with the as cast (non alloy ductile iron). The higher impact energy value obtained at 9000 C austenization and 375o C austempering temperatures during 60 minutes holding times. The structure changes into ausferrit.
Study Effect of Salt Washing Process on Content and Iodium Stability of Salt Saksono, Nelson
Makara Journal of Technology Vol. 6, No. 1
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Abstract

Effect of Salt Washing Process on Content and Iodium Stability of Salt. Salt washing process should increase the salt quality. It should clean the salt from sludge or clay and also reduce the impurity compound such as Mg, Ca and the reductor content. The objective of these reseach is to assess the effect of washing process on the content og hygroscopic impurities compound (Ca and Mg), and reductor content of salt. The research also investigate the water absorbing, pH, KIO3 content as function of time to obtain effect of washing process on KIO3 stability in salt. The experiment result shows that the lowest content of Mg and reductor compound 0.016 % wt and 2.65 ppm respectively which is reached at the fi ne salt washing process using 27 % wt brine. The analysis of water content indicates an increase the Ca and Mg content, causing an water absorbtion in salt , However the effect on pH the is not clear.
Develops The Software of DSP Processor for the CDMA circuitry D., Arman Djohan
Makara Journal of Technology Vol. 6, No. 1
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Abstract

This research develops the software of DSP Processor type TMS320C54X for the CDMA circuitry. This research apply two algorithms namely Mathematic Algorithm and table lookup Algorithm. From both algorithms, the research examine what algorithm have the fasted processing time and the smallest memory occupation. From the examination results the Mathematic Algorithm have 20.62 milliseconds processing time and the Table lookup algorithm have 14.08 milliseconds processing time. The Table lookup algorithm have the fastest processing time because the Matematic algorithm need the rounding process of the fi gure. Eventhough such processing time is not exceed from the 125 millisecond of delay time, in real condition, the total processing time are include the error correction processing time and voice compression processing time such as ADPCM or QCELP voice compression techniques.

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