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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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Design and Implementation of 1-2 GHz Stepped Frequency GPR for Buried Metal Detection Suryana, Joko; Suksmono, Andriyan B.; Mengko, Tati R.
Makara Journal of Technology Vol. 9, No. 2
Publisher : UI Scholars Hub

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Abstract

Design and Implementation of 1-2 GHz Stepped Frequency GPR for Buried Metal Detection. In this paper, we describe the design and realization steps of 1 – 2 GHz SFGPR (Stepped Frequency Ground Penetrating Radar) transceiver for metal detection under the ground. Before using prototyped GPR for detecting the metal under the ground, several of calibration processes must be performed, namely phase calibration and monocycle pulse waveform calibration. After completing the calibrations, this prototyped GPR would be ready for detecting a hidden object such as a metal plate 5 cm under the ground in our small test range size 25 cm x 75 cm x 10 cm. From the calibration and detection results, we concluded that the prototyped SFGPR passed the technical specifications of the design and could perform the metal detection under the ground with high SNR.
Simultaneous Treatment of Organic (Phenol) and Heavy Metal (Cr6+ or Pt4+) Wastes over TiO2, ZnO-TiO2 and CdS-TiO2 Photocatalysts Slamet, Slamet; Arbianti, R.; Daryanto, Daryanto
Makara Journal of Technology Vol. 9, No. 2
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Simultaneous Treatment of Organic (Phenol) and Heavy Metal (Cr6+ or Pt4+) Wastes over TiO2, ZnO-TiO2 and CdS-TiO2 Photocatalysts. Treatment of heavy metal (Cr6+ and Pt4+) and organic (phenol) wastes has been studied using the relatively new method, i.e. simultaneous photocatalytic process over TiO2 photocatalysts in the batch photoreactor. Following the photocatalytic reduction of the heavy metal wastes, recovery of Cr and Pt was carried out by precipitation and leaching method, respectively. The experimental results show that in the simultaneous photocatalytic system, there is a synergism effect between the photocatalytic reduction of heavy metal waste (Cr6+ or Pt4+) and the oxidation of organic waste (phenol), so that increasing the conversion of each other. Dopant of ZnO with the optimum loading (0.5 wt%) could slightly increase the performance of TiO2 photocatalyst in photocatalytic treatment of the wastes. Whereas CdS dopant with the optimum loading of 1 wt% could significantly enhance the performance of TiO2 photocatalyst in simultaneous Cr(VI) reduction and phenol oxidation with the highest conversion of ≥ 97 % and 93 %, respectively. Photocatalytic reduction of Pt(IV) under 0.5%ZnO-TiO2 and 1%CdS-TiO2 photocatalysts effectively occurred with a high conversion (> 99 %) in 2 hours irradiation of UV. The optimum precipitation condition of Cr(III) recovery was achieved at pH = 9, with the efficiency of recovery was 91 %. Optimum temperature of leaching process in Pt recovery was 100 oC, with the efficiency of recovery was 86 %.
Design of Generating Dual Frequency Operation for Triangular Microstrip Antenna Using Electromagnetic Coupling Surjati, Indra; Rahardjo, Eko Tjipto; Hartanto, Djoko
Makara Journal of Technology Vol. 9, No. 2
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Abstract

Design of Generating Dual Frequency Operation for Triangular Microstrip Antenna Using Electromagnetic Coupling. A new design is proposed in this paper by applying a pair of slits using a microstrip feed line. Therefore the microstrip line feeding system is electromagnetically coupled to the patch. The antenna works at two different frequencies in the range from 2 GHz to 4 GHz (S band frequency). The results of the simulation shows that the dual frequency operation can be created when the slit width is 1 mm and the height of the slits ranges from 10 mm to 14 mm with inter slit distance of 3 mm, 5 mm and 7 mm as well.
On The Performance of Imt-2000 Communication Link Based on Stratospheric Platforms Iskandar, Iskandar; Shimamoto, Shigeru
Makara Journal of Technology Vol. 10, No. 1
Publisher : UI Scholars Hub

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Abstract

A new means for providing wireless communication has been currently proposed. It is based on aerial vehicle known as High Altitude Platform or Stratospheric Platforms (SPF). The SPF will be operated at an altitude of 17-22 km above the ground. Therefore, the channel condition may be different compared with those of the conventional terrestrial or satellite wireless channel. In this paper, the channel propagation characteristic of such a system is firstly investigated by means of ray tracing algorithm. We emphasize our investigation in a typical urban environment, in which the mobile users mostly exist. We developed building block model for simulation based on building height distribution, which is obtained from measurement inside Tokyo. As a result, propagation loss model and Ricean channel parameter for the SPF channel is reported in different scenarios. By using this result we then estimate the required transmitted power of SPF to serve the mobile users in a several transmission rate that is used in IMT-2000 services. Finally, an evaluation of BER of IMT-2000 link is performed in order to estimate the system level performance. From this evaluation, the main contribution of this paper is to clearly show the critical limitations of both power requirement as well as system level performance of mobile communication IMT-2000 by using the concept of the SPF.
Effect of Firing Temperature and Holding Time on Characterization of Al/SiC Metal Matrix Composites Produced by Pressureless Infiltration. Zulfia, Anne; Ariati, Myrna
Makara Journal of Technology Vol. 10, No. 1
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Effect of Firing Temperature and Holding Time on Characterization of Al/SiC Metal Matrix Composites Produced by Pressureless Infiltration. The production of Al-SiC metal matrix composite can be carried out by pressureless metal infiltration processs (PRIMEX). The experiment was conducted using aluminium AC2B ingot as a matrix and 50%Vf SiC powder as a reinforcement which is mixed with 10% Mg powder for wetting agent. The variables of this experiment are holding time and firing temperature to investigate the effect of these conditions on mechanical properties of Al-SiC metal matrix composites. Holding time was conducted for 2,5,8,10,12 hours and firing temperatures was 750, 800, 900, 1000, 1100°C respectively.. The composites produced are analysed both mechanical properties and metalography such as densities, porosities, hardness, as well as wear rate. The results showed that the longer holding time and increasing firing temperature will increase mechanical properties of Al-SiC metal matrix composites, and it is found that the optimum mechanical properties at 1000°C for 10 hour.
Analysis of Technical Energy Losses By Using Simulation Betrianis, Betrianis; Herawan, Randite
Makara Journal of Technology Vol. 10, No. 1
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Abstract

Model is a representation of a system. Through model, it can be easier to forecast and control the changing of each element system. Electricity distribution is also a system. Losses are general problem that exist in a distribution network system. But with the right methods, specifically technical energy losses can be reduced in order to increase the efficiency. By making model of the distribution network, the value of technical energy losses in the whole network as well as in every line can be observed. Simulation can also be used to see all losses reduction alternatives. By comparing results from each alternatives, the best alternative, which gives best result can be decided and implemented.
Modification of Bonding Strength Test of WC HVOF Thermal Spray Coating on Rocket Nozzle Sofyan, Bondan T.; Pardede, Haposan J.; Stefano, Marizki; Sofyan, Edi
Makara Journal of Technology Vol. 10, No. 1
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Modification of Bonding Strength Test of WC HVOF Thermal Spray Coating on Rocket Nozzle. One way to reduce structural weight of RX-100 rocket is by modifying the nozzle material and processing. Nozzle is the main target in weight reduction due to the fact that it contributes 30 % to the total weight of the structur. An alternative for this is by substitution of massive graphite, which is currently used as thermal protector in the nozzle, with thin layer of HVOF (High Velocity Oxy-Fuel) thermal spray layer. This paper presents the characterization of nozzle base material as well as the modification of bonding strength test, by designing additional jig to facilitate testing processes while maintaining level of test accuracy. The results showed that the material used for RX-100 rocket nozzle is confirmed to be S45C steel. Modification of the bonding strength test was conducted by utilizing chains, which improve test flexibility and maintains level of accuracy of the test.
Modeling of Coupled-Tank System Using Fuzzy Takagi-Sugeno Model Subiantoro, Aries
Makara Journal of Technology Vol. 10, No. 1
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Modeling of Coupled-Tank System Using Fuzzy Takagi-Sugeno Model. This paper describes modeling of coupledtank system based on data measurement using fuzzy Takagi-Sugeno model. The fuzzy clustering method of Gustafson- Kessel algorithm is used to classify input-output data into several clusters based on distance similarity of a member of input-output data from center of cluster. The formed clusters are projected orthonormally into each linguistic variables of premise part to determine membership function of fuzzy Takagi-Sugeno model. By estimating data in each cluster, the consequent parameters of fuzzy Takagi-Sugeno model are calculated using weighted least-squares method. The resulted fuzzy Takagi-Sugeno model is validated by using model performance parameters variance-accounted-for (VAF) and root mean square (RMS) as performance indicators. The simulation results show that the fuzzy Takagi-Sugeno model is able to mimic nonlinear characteristic of coupled-tank system with good value of model performance indicators.
Design of Induction Motor Drive Without Velocity Sensor Using Current Vector Controller with Full and Reduced Observer Moving to DQ Axis Gunawan, Ridwan; Yusivar, Feri; Wahab, Wahidin; Kadir, Zuhal A.
Makara Journal of Technology Vol. 10, No. 1
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Design of Induction Motor Drive Without Velocity Sensor Using Current Vector Controller with Full and Reduced Observer Moving to DQ Axis. The observer is used in estimation velocity sensor usually in α-β axis, therefore this situation will need an extra transformation when we want to add compensator because the flux model is in direct and quadrature-axis dq. Every used the transformation to make possible emerge an error. So in this simulation is used a method to estimate the velocity of induction motor drive with observer that is moved to dq-axis. The model of actual motor used is in alfa-beta axis, but the observer use the motor models in rotor flux oriented control (RFOC).This matter, also to prove that the different models of motor drives can be used between the actual and estimated one. The simulation results with C-MEX S-function Matlab/Simulink 6.5 to show that the full order observer in dq axis gives better performance than the reduced order observer.
Hybrid Identification System with ARX and Fast Fourier Transform in Application of a Quarter of Vehicle Half Active Suspension M, Noveri Lysbetti; R., Antonius
Makara Journal of Technology Vol. 10, No. 1
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Hybrid Identification System with ARX and Fast Fourier Transform in Application of a Quarter of Vehicle Half Active Suspension. In a control system problem, identification system mechanism is a absolute thing, especially in adaptation controlling to disturbance changing. For that case, is needed an identification method which can identify the changing of disturbance in that system. The aim of this research is to give an alternative in system/plant identification which is a combination (hybrid) of ARX and Fast Fourier Transform. So, it is needed an algorithm design for identification process. In this case, the designed algorithm will be implemented in software that works based on Matlab. The result of car mass 500Kg in seventh second with first way disturbance is the biggest frequency at this time. Operation frequency produced is 27.4889Hz, estimation model magnitude is 1.3431E-006 and estimation model phase is -86.8307. The result of car mass 1000Kg in 15th-second, with second way disturbance is the biggest frequency at this time. Operation frequency produced is 3.9270Hz, estimation model magnitude is 1.1780E-006 and estimation model phase is 131,5950. These results show that as lighter car mass when disturbance happened by road surface, as bigger the operation frequency happen.

Page 8 of 49 | Total Record : 485

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