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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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Electron Emission Characteristics of Multi-gated Field Emitters Mimura, Hidenori; Neo, Yoichiro; Aoki, Toru; Yoshida, Tomoya; Nagao, Masayoshi
Makara Journal of Technology Vol. 18, No. 2
Publisher : UI Scholars Hub

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Abstract

We have developed a multi-gated field emitter (FE) such as a quadruple-gated FE with a three-stacked electrode lens and a quintuple-gated FE with a four-stacked electrode lens. Both the FEs can focus the electron beam. However, the quintuple-gated FE has a stronger electron convergence than the quadruple-gated FE, and a beam crossover is clearly observed for the quintuple-gated FE.
The Gaussian Orthogonal Laplacianfaces Modelling in Feature Space for Facial Image Recognition Muntasa, Arif
Makara Journal of Technology Vol. 18, No. 2
Publisher : UI Scholars Hub

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Abstract

Dimensionality reduction based on appearance has been interesting issue on the face image research fields. Eigenface and Fisherface are linear techniques based on full spectral features, for both Eigenface and Fisherface produce global manifold structure. Inability of them in yielding local manifold structure have been solved by Laplacianfaces and further improved by Orthogonal Laplacianfaces, so it can yield orthogonal feature vectors. However, they have also a weakness, when training set samples have non-linear distribution. To overcome this weakness, feature extraction through data mapping from input to feature space using Gaussian kernel function is proposed. To avoid singularity, the Eigenface decomposition is conducted, followed by feature extraction using Orthogonal Laplacianfaces on the feature space, this proposed method is called Kernel Gaussian Orthogonal Laplacianfaces method. Experimental results on the Olivetty Research Laboratory (ORL) and the YALE face image databases show that, the more image feature and training set used, the higher recognition rate achieved. The comparison results show that Kernel Gaussian Orthogonal Laplacianfaces outperformed the other method such as the Eigenface, the Laplacianfaces and the Orthogonal Laplacianfaces.
Observation of Tunneling Effects in Lateral Nanowire pn Junctions Purwiyanti, Sri; Udhiarto, Arief; Moraru, Daniel; Mizuno, Takeshi; Hartanto, Djoko; Tabe, Michiharu
Makara Journal of Technology Vol. 18, No. 2
Publisher : UI Scholars Hub

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Abstract

As electronic device dimensions are continuously reduced, applied bias conditions significantly change and the transport mechanisms must be reconsidered. Tunneling devices are promising for scaled-down electronics because of expected high-speed operation and relatively low bias. In this work, we investigated the tunneling features in silicon-oninsulator lateral nanowire pn junction and pin junction devices. By controlling the substrate voltage, tunneling features can be observed in the electrical characteristics. We found that the minimum substrate voltage required for tunneling to occur in pn junctions is higher as compared with pin junctions. The main cause of these effects relies in the difference between the doping profiles, since the pn junctions contain a co-doped region, while the pin junctions contain an i-layer.
Series-Interconnected Plastic Dye-Sensitized Solar Cells Prepared by Low- Temperature Binder-Free Titania Paste Rosa, Erlyta Septa; Muliani, Lia; Shobih, Shobih; Hidayat, Jojo; Yuliarto, Brian
Makara Journal of Technology Vol. 18, No. 2
Publisher : UI Scholars Hub

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Abstract

The aim of this research is to study dye-sensitized solar cells (DSSC). This was implemented on a flexible polyethylene terephthalate (PET) substrate using a mixture of transparent and scattered mesoporous anatase-titania as the electron transport layer for the photoelectrode. This mixture of anatase titania performed a dual function of light scattering and efficient dye absorption. In this study, a porous nano-TiO2 film was prepared on indium tin oxide (ITO) coated polyethylene terephthalate (PET) by using a binder-free titania paste; on it, a DSSC was fabricated. The paste which contained a mixture of TiO2 nanoparticles, acid chloride, and ethanol was printed on two patterns of 1x6 cm2 active areas followed by sintered at 120 ºC to form TiO2 films. A commercial dye, N719, was adsorbed on the surface of TiO2 films and assembled to two platinized conductive plastic patterns to form a counter electrode and thus a sandwich-type dye cell. Finally, a solution of KI/I2 electrolytes was injected into the cell in which a couple of sandwich-type dye cells with an active area of 6 cm2 for each cell were series interconnected with a z-type interconnection between the photoelectrode of one cell and the counter electrode of another cell. The cell performance was characterized by employing simulated solar light at an intensity of 50 mW/cm2. The results showed interconnected cells generating a short-circuit photocurrent density of 2.34 mA/cm2, an open-circuit voltage of 1.10 volt, and overall 0.172% power conversion efficiency.
Design of GaN-Based Low-Loss Y-Branch Power Splitter Purnamaningsih, Retno Wigajatri; Saraswati, Irma; Poespawati, Nji Raden; Dogheche, Elhadj
Makara Journal of Technology Vol. 18, No. 3
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Abstract

We present a Y-branch power splitter design with a multimode section using GaN on Sapphire at telecommunication wavelength. The GaN sample optical properties were also investigated, resulting in a refractive index for the GaN layers nTE=2.289±0.001 and nTM=2.324±0.00. Optimization of the structure parameters for this structure was conducted accurately using BPM methods. The results demonstrated the possibility of realizing a GaN-based Y-branch power splitter for various applications.
Ultra-Wideband Notched Characteristic Fed by Coplanar Waveguide Hadinegoro, Rastanto; Ningsih, Yuli Kurnia; Surjati, Indra
Makara Journal of Technology Vol. 18, No. 3
Publisher : UI Scholars Hub

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Abstract

In this paper, a novel Ultra-Wide Band (UWB) notch patch antenna with co-planar waveguide (CPW) fed is presented. This antenna only used one layer and the patch antenna is constructed on the first layer and back to back with CPW fed and bottom part is ground plane. The width notch is used to achieve the UWB characteristic. The results shown that the impedance bandwidth is 1130 MHz (1.662–2.792 GHz) or about 50.7% for VSWR <2.
Development of the Soekarno–Hatta International Airport Rail Link Project Using the Value Engineering Method: Creating Value for Money Berawi, Mohammed Ali; Susantono, Bambang; Dikun, Suyono; Ilyas, Tommy; Rahman, Herawati Zetha; Berawi, Abdur Rohim Boy; Zagloel, Teuku Yuri; Miraj, Perdana; Petroceany, Jade Sjafrecia
Makara Journal of Technology Vol. 18, No. 3
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Abstract

Soekarno–Hatta Airport is the main gateway for international flights to Greater Jakarta. Its accessibility depends on the inter-city and Sedyatmo toll roads, which causes congestion in peak hours, leading to uncertainty about travel times. The Soekarno–Hatta International Airport Rail Link (SHIARL) is proposed as an alternative mass transportation project, which is expected to provide accessibility and mobility for people and goods to and from the airport. Previously, the project was unattractive to private investors as it was technically and financially unfeasible. Therefore, this research aims to improve the feasibility of the Soekarno-Hatta International Airport Rail Link (SHIARL) by using a value-engineering approach to create maximum value for money for the project. This research combines quantitative and qualitative methods. Questionnaire surveys are distributed to various stakeholders in the project, and a focus-group discussion (FGD) is conducted. The results identified additional, innovative functions through the integration of the Mass Rapid Transit (MRT), flood control, telecommunications, and development in the downtown area around the station. The life-cycle cost analysis confirmed the increased value for money because of the project’s additional functions, including a positive Net Present Value (NPV). Moreover, the findings showed that the internal rate of return (IRR) was 3% higher than the original single-function project.
Analysis of Vibration Generated by the Rubbing of Flat Surfaces Fuadi, Zahrul
Makara Journal of Technology Vol. 18, No. 3
Publisher : UI Scholars Hub

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Abstract

Among the phenomena that occur as a result of contact between two surfaces is friction sound, in which surface roughness is of great importance. In this study, the parameter of contact stiffness is used to explain the frequency characteristic of vibration generated by the rubbing of flat surfaces under a small load. A 3-disk configuration rubbing method was used, which provides a unique characteristic of the system's frequency response function containing specific information about the rubbing vibrations. It is shown that the peak frequency of the rubbing vibration can be explained by using a two-degrees-of-freedom model incorporating the parameter of contact stiffness. A quantitative relationship between the surface roughness and the peak frequency of the rubbing vibrations was established.
The Mechanical and Tribology Properties of Sputtered Titanium Aluminum Nitride Coating on the Tungsten Carbide Insert Tool in the Dry Turning of Tool Steel Budi, Esmar; bin Muhamad, Mohd. Razali; Rahman, Md. Nizam bin Abdul
Makara Journal of Technology Vol. 18, No. 3
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Abstract

The effect of the sputtering parameters on the mechanical tribology properties of Titanium Aluminum Nitride coating on the tungsten cabide insert tool in the dry turning of tool steel has been investigated. The coating was deposited using a Direct Current magnetron sputtering system with various substrate biases (-79 to -221 V) and nitrogen flow rates (30 to 72 sccm). The dry turning test was carried out on a Computer Numeric Code machine using an optimum cutting parameter setting. The results show that the lowest flank wear (~0.4 mm) was achieved using a Titanium Aluminum Nitride-coated tool that was deposited at a high substrate bias (-200 V) and a high nitrogen flow rate (70 sccm). The lowest flank wear was attributed to high coating hardness.
Modified Design of Pin-on-Ring Tribometer for Hip Joint Prostheses Measurement; Case Study on Salat Activity Khafidh, Muhammad; Jamari, Jamari; Sulardjaka, Sulardjaka; Tauviqirrahman, Mohamad; Heide, Emile van der
Makara Journal of Technology Vol. 18, No. 3
Publisher : UI Scholars Hub

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Abstract

Total hip replacement (THR) is one of the most successful orthopedic surgical procedures for replacing a broken hip joint. In THR, wear may occur at the articulating surface of the acetabular cup and the femoral head. In Indonesia, the country with the largest Muslim population in the world, most of the inhabitants do salat (praying) every day. THR users are banned from doing salat for fear it will damage the hip joint prostheses. The previous wear calculation methods on the hip joint prostheses use the gravimetric, coordinate measuring machine (CMM), profiler, and geometric method. The disadvantages of the previous methods are that the geometry of the wear patch and the wear volume are only known at the end of the experiment, so they cannot be used to calculate the specific wear rate values in real time. So far, in every modeling of the hip joint prostheses, the values of the specific wear rate are assumed to be constant. This paper reports on the design modification of a pin-on-ring tribometer that is used to measure the wear volumes in hip joint prostheses. The result shows that modifications of the femoral head holder, reciprocating motion, elastic joint, and extra displacement transducer is needed to get the specific wear rate value. The calculation method to find the delta volume that is the value of displacement less than the displacement minimum (δmin) is based on a graph, while the calculation method to find the delta volume that is the value of displacement that is more than the displacement minimum (δmin) is based on an equation. In the salat test protocol, the longest test time was during the sujud (prostration) motion, which took 1034.17 minutes in the experiment.

Page 27 of 49 | Total Record : 485

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