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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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Role of K3-xHxPW12O40 as a Catalyst in Selective Catalysis of Methylamine Synthesis from Ammonia and Methanol Nasikin, Mohammad
Makara Journal of Technology Vol. 7, No. 3
Publisher : UI Scholars Hub

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Abstract

Role of K3-xHxPW12O40 as a Catalyst in Selective Catalysis of Methylamine Synthesis from Ammonia and Methanol. Synthesize of methylamine from methanol and ammonia was studied in this research work using a partially potassium heteropoly salt (K3-xHxPW12O40 abbreviated as KPW) as a catalyst. KPW was prepared from heteropoly salt and potassium carbonate by using ion exchange method. The reaction was conducted at 600 ~ 800K and at the atmospheric pressure. Reactor used was a continue flow reactor with W/F=0,1~0,9g-kat.mnt./cc.Concentration of reactants and products were analyzed by gas chromathography while catalyst structure was observed by XRD (X-ray diffraction). Isothermal adsorption method was used for determining catalyst pore size. The result showed that ion exchange between H ion in zeolit with K ion produced potassium heteropoly salt that caused the change of interstitial space. The change of interstitial space was observed by the change of the lattice constant of the catalyst crystal. Trimethylamine(TMA) has molecule size smaller than catalyst pore size but bigger than molecular size of Dimethylamine (DMA) and Monimethylamine (MMA). This phenomenon caused the suppression of TMA formation. KPW has a rigid crystal structure and stabil during reaction. On the other hand, crystal structure of a non selective catalyst (NH4)3PW12O40 was not rigid and its pore size is easy to change depending on the product molecule size.
Study on Electrochromic Effect of Polyaniline Film Handojo, Lienda; Simangunsong, Junus
Makara Journal of Technology Vol. 7, No. 3
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Abstract

Study on Electrochromic Effect of Polyaniline Film. The light transmission factor of an electrochromic film changes reversibly with the application of an electrical voltage. Thereby the transparent film becomes reversibly opaque so that it may be used to control light transmission. In this paper the results of a study on polyaniline film as an electrochromic active material is reported. Polyaniline looks yellow transparent in the reduced state and turns to green-blue at its oxidized state. The electrochromic device considered in this paper was fabricated in planar configuration of ITO glass − polyaniline film − electrolyte − ITO glass which involved 1.0M H2SO4 solution. The measurement of the current density yields voltamograms for several values of the rate of voltage change, while the optical characteristics were measured with ultraviolet-visible spectroscopy. To inspect the light control properties, the intensity of solar radiation propagating through the device was derived. It is found that in its reduced state, the device transmits 70% of the incoming radiation, while in the oxidized state only 11% of the radiation is left. The result of recycling test indicated that film is stable over 5,000 cycles.
Application of Tabu Search Algorithm in Job Shop Scheduling Betrianis, Betrianis; Aryawan, Putu Teguh
Makara Journal of Technology Vol. 7, No. 3
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Abstract

Application of Tabu Search Algorithm in Job Shop Scheduling. Tabu Search is one of local search methods which is used to solve the combinatorial optimization problem. This method aimed is to make the searching process of the best solution in a complex combinatorial optimization problem(np hard), ex : job shop scheduling problem, became more effective, in a less computational time but with no guarantee to optimum solution.In this paper, tabu search is used to solve the job shop scheduling problem consists of 3 (three) cases, which is ordering package of September, October and November with objective of minimizing makespan (Cmax). For each ordering package, there is a combination for initial solution and tabu list length. These result then compared with 4 (four) other methods using basic dispatching rules such as Shortest Processing Time (SPT), Earliest Due Date (EDD), Most Work Remaining (MWKR) dan First Come First Served (FCFS). Scheduling used Tabu Search Algorithm is sensitive for variables changes and gives makespan shorter than scheduling used by other four methods.
The Selection of Materials for Roller Chains From The Perspective Of Manufacturing Process Saptono, Rahmat
Makara Journal of Technology Vol. 7, No. 3
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Abstract

The selection of materials for an engineering component is not only requested by its design function and shape, but also the sequence through which it is manufactured. The manufacturing operation of roller chains involves drawing and trimming processes aimed at producing semi-finished chain drives component with a well-standardized dimension. In addition to final combination of properties required by design constraints, the ability of materials to be formed into a desired shape and geometry without failure is also critical. The objective of materials selection should therefore involve additional attributes that are not typically accommodated by the standard procedure of materials selection. The present paper deals with the selection of materials for roller chains from the perspective of manufacturing process. Ears and un-uniform wall thickness have been identified as a key problem in the mass production of component. Provided all process parameters were established, the anisotropy factor of materials is critical. Simulative test can be reasonably used to obtain material performance indices that can be added up to the standard procedure of material selection. Of three commercially available steel grades evaluated with regard to the criteria defined, one grade is more suitable for the present objective.
Adoption of Variable Rate Technology Surjandari, Isti; Batte, Marvin T.
Makara Journal of Technology Vol. 7, No. 3
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Abstract

Site Specific Management (SSM), which also variously referred to as Variable Rate Technology (VRT), is an emerging technology that enables producers to make more precise input application decisions based on soil and field characteristics. This study analyzes factors influencing the adoption of VRT for fertilizer application for cash grain production in Ohio. Results show that producer and field characteristics might influence the adoption decision on various SSM components differently. It also provides insight as to the sequence of adoption of SSM component technologies and how this sequence might differ for producers of differing characteristics.
An Economic Analysis of Variable Rate Technology Surjandari, Isti; Batte, Marvin T.; Miranda, Mario J.
Makara Journal of Technology Vol. 7, No. 3
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Abstract

Variable Rate Technology (VRT) offers an opportunity to improve production efficiency by allowing input applications to fluctuate in response to spatial variations in soil characteristics and nutrient levels. Society may also benefit from reduced negative externalities, such as surface and groundwater contamination, from input applications. Using a dynamic spatial model, this study examines how the interaction among variability, spatial autocorrelation, and mean level of soil fertility affects optimal sampling density and the economic gains from VRT. VRT was found to be profitable under selected conditions, and the optimal grid size will vary with these conditions. In the case where variability and mean fertility levels are significantly high associated with low spatial autocorrelation, VRT produces greater net returns than Uniform Rate Technology (URT), even with the smallest grid size to base the input application decisions. Results also demonstrate that optimal grid size increases with increased spatial autocorrelation.
Quarternair CuGaSeTe and CuGa0.5In 0.5Te2 Thin Films Fabrication Using Flash Evaporation Soepardjo, A. Harsono
Makara Journal of Technology Vol. 8, No. 1
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Quarternair CuGaSeTe and CuGa0.5In 0.5Te2 Thin Films Fabrication Using Flash Evaporation. Quarternair materials CuGaSeTe and CuGa0.5In 0.5Te2 are the basic materials to solar cell fabrication. These materials have high absorption coefficients around 103 – 105 cm-1 and band gap energy in the range of 1-5 eV. In this research, the films were made by flash evaporation method using quarternair powder materials of CuGaSeTe and CuGa0.5In 0.5Te2 to adhere in a glass substrate. After the films were obtained, the properties of these films will be characterized optically and electrically. The lattice parameter of the films and the crystalline film structure were obtained using X-Ray Diffraction (XRD) spectroscopy. The XRD results show that the quarternair CuGaSeTe and CuGa0.5In 0.5Te2 films have a chalcopyrite structure. The absorption coefficient and the band gap energy of the films were calculated using transmittance and reflectance patterns that measured using UV-VIS Difractometer. The films composition can be detected by using the Energy Dispersive Spectroscopy (EDS), while the films resistivity, mobility and the majority carrier of the films were obtained from Hall Effect experiments.
Construction of Depth-Structure Shelf-edge Map for Case Study of Kujung Formation, East Java Sea Rusli, Saifatur; Suparto, Suparto
Makara Journal of Technology Vol. 8, No. 1
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Construction of Depth-Structure Shelf-edge Map for Case Study of Kujung Formation, East Java Sea. In general, reflection seismic method has capability to represent sub-surface in time domain. Seismic cross-section that depicts the formation of sub-surface usually use time domain in the format of TWT (Two Way Times). This due to in the process of seismic data acquisition, seismic wave propagates in down-going and up-going manner so that the obtained results from data processing are in the format of TWT seismic vs. shot points. This paper will describe the construction of depth-structure map for case study of Kujung Formation, East Java Sea, as exploration activities of oil companies in Indonesia. Manual data is peaked from seismic cross section and crossed with Vrms data of 3 wells in exploration location. TWT Shelf-edge map of Kujung Formation is divided into 2 parts and the results is crossed with velocitystructure map using Geoframe software CPS-3 so that depth-structure of shelf-edge of Kujung Formation, East Java Sea, is obtained. One of the objectives of this map construction is to get more real visualization of sub surface by using depth domain approach and as sustainable exploration activities of oil companies in Indonesia.
PID Fuzzy Logic Controller System for DC Motor Speed Control M., H. Samsul Bachri
Makara Journal of Technology Vol. 8, No. 1
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Abstract

PID Fuzzy Logic Controller System for DC Motor Speed Control. A good controller system must have resilience to disturbance and must be able to response quickly and accurately. Problem usually appears when PID controller system was built sensitively hence the system’s respon to the disturbance will yield big overshot/undershot then the possibility of oscillation to be happened is excelsior. When the controller system was built insensitively, the overshot/undershot will be small but the recovery time will be longer. Hybrid controller system could overcome those problems by combining PID control system with fuzzy logic. The main control of this system is PID controller while the fuzzy logic acts to reduce an overshot/undershot and a recovery time. The fuzzy logic controller is designed with two input error and delta error and one output of the motor speed. The output of fuzzy logic controller should be only half of the PID controller for limiting entirely fuzzy output. This hybrid system design has a better respon time controller system than PID controller without fuzzy logic.
Graded Channel MOSFET simulation with S-Pisces 2B Siswono, Hartono
Makara Journal of Technology Vol. 8, No. 1
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Graded Channel MOSFET simulation with S-Pisces 2B. Graded-Channel Metal-Oxide-Semiconductor Field-effect- Transistor or GCMOSFET is being discussed in this paper. GCMOSFET technology has been developed to meet the growing demand for low power and high performance application. In this paper, it will be shown that, compared to ungraded MOSFET, the GCMOSFET device offers the advantage of significantly higher drive current. The higher drive current is achieved because the effecctive channel length of GCMOSFET is shorter than the ungraded MOSFET’s. From the simulation result with S-PISCES 2B and MATLAB, it can been shown that the ID from GCMOSFET is higher than the ID from ungraded MOSFET. As an example, with VG = 4 V and VD = 4 V, ID from MOSFET is equal with 9.78 e-06 A and ID from GCMOSFET is equal with 16.56 e-06 A. Beside that, as an example, to get ID = 1.13 e-05 A with MOSFET will need VG = 4 V and VD = 4.7 V, and with GCMOSFET VG = 4 V and VD = 1.2 V will be needed. This result has shown that GCMOSFET needs lower supply voltage than the ungraded MOSFET which means that GCMOSFET needs lower power consumption than ungraded MOSFET. From the simulation results, it can be proved that GCMOSFETwith shorter LGC (graded channel region length) will give larger ID than ID from GCMOSFET with longer LGC. As we can see that for VGS = 4 V and VDS = 2 V, GCMOSFET with LGC = 4 μm will give ID = 16,56E-06 A, GCMOSFET with LGC = 3,5 μm will give ID = 17,51E-06 A, and GCMOSFET with LGC = 3 μm will give ID = 18,49E-06

Page 5 of 44 | Total Record : 439

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