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INDONESIA
Makara Journal of Technology
Published by Universitas Indonesia
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Core Subject : Science,
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Articles 8 Documents
Search results for , issue " Vol 19, No 1 (2015)" : 8 Documents clear
Fiber Optic Ring Resonator Sensor Detection Technique Based on Spectral Intensity Integration Sidi Priambodo, Purnomo; Raharjo, Sasono; Witjaksono, Gunawan; Hartanto, Djoko
Makara Journal of Technology Vol 19, No 1 (2015)
Publisher : Directorate of Research and Community Services, Universitas Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.7454/mst.v19i1.3027

Abstract

Resonant field phenomenon in optical ring resonator has been a major theme for various studies and can be used for various sensor applications. The spectral response shape changes are subjects to be discussed and analyzed for detection in optical sensor system. The spectral response changes are caused by various factors ranging from refractive index of the surrounding medium, medium loss due to absorption and scattering, and coupling variation between waveguides. These optical phenomena are mostly used for bio-sensor applications, since it is free from electromagnetic interference (EMI) and non-physically destructive. In this paper, we discuss our current research in developing optical bio-sensor in the form of a fiber optic ring resonator with monochromatic laser source based on spectral integration detection method, which is sufficiently sensitive and accurate.
Hazard-Driven Drivers’ Behaviours towards Vehicle-to-Median Safe Distances Siregar, Martha Leni
Makara Journal of Technology Vol 19, No 1 (2015)
Publisher : Directorate of Research and Community Services, Universitas Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.7454/mst.v19i1.3023

Abstract

A median is required for a two-way road to separate traffic from opposing lanes and to prevent head-on collisions. However, studies indicate that medians are also perceived as hazards which need to be avoided during driving. This hazard perception is manifested in drivers’ changing behavior towards various types of medians along the driving lanes inform of their tendency to allow various safe distances to the medians. The Indonesian Highway Capacity Manual (IHCM) does not differentiate between types of medians and the influence on the drivers’ choice of safe margin to the medians. Therefore, this study looks into how the existence and types of medians influence the safety distances of different categories of vehicles from different types of medians as the manifestation of their perception of hazard potentials of medians. Traffic recordings on different categories of vehicles are used to obtain movement margins of vehicles along various medians during near-saturated traffic. Using the smallest values of 10 and 90 percentile of distances, the results show that drivers shy from 0.27 m to 0.82 m from medians. The result of this study will contribute to the change of applied assumptions used in determining the effective lane capacity to road safety-based assumptions.
The Effects of the Types of Milk (Cow, Goat, Soya) and Enzymes (Rennet, Papain, Bromelain) Toward Cheddar Cheese Production Arlene, Ariestya; Prima Kristijarti, Anastasia; Ardelia, Ivana
Makara Journal of Technology Vol 19, No 1 (2015)
Publisher : Directorate of Research and Community Services, Universitas Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.7454/mst.v19i1.3028

Abstract

The objectives of this research are to study the effects of different types of milk and enzymes toward the yield and quality (moisture, ash, protein, fat content, and texture) of cheddar cheese and the interaction between those two variables during the process. The types of milk are cow, goat, and soya milk, while the types of enzymes are rennet, papain, and bromelain enzymes. Regarding the procedure, the milk is first pasteurized before CaCl2 and Lactobacillus lactis that acts as the acidifier starter as much as 0.2% (w/v) and 0.5% of the milk volume are added respectively. The amount of enzyme added is appropriate for the determination of enzyme dose. The curd is separated from the whey and then 2.5 grams of salt is added to 100 grams of curd. Afterwards, the curd is pressed until the water content decreases (cheese), then ripened for 1 month. The analyses conducted are moisture, ash, protein, fat content, and texture (hardness). The conclusion is the goat milk and the rennet enzyme are the suitable raw material for cheddar cheese production. Furthermore, different types of milk and enzymes affect the yield. However, there is no interaction between the types of milk and enzymes to the yield.
Construction of a Novel Method of Measuring Thermal Conductivity for Nanostructures Ikeda, Hiroya; Yoshida, Shoma; Suzuki, Yuhei; Manimuthu, Veerappan; Salleh, Faiz; Kuwahara, Fujio; Shimomura, Masaru; Murakami, Kenji
Makara Journal of Technology Vol 19, No 1 (2015)
Publisher : Directorate of Research and Community Services, Universitas Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.7454/mst.v19i1.3024

Abstract

With the aim of characterizing the thermal conduction in a nanometer-scaled materials, we have constructed a novel method on the basis of an ac calorimetric method. In this method, periodic sample heating is performed by light irradiation and the corresponding periodic temperature is detected by infrared irradiative thermometer. This makes us measure the thermal diffusivity out of contact with the objective sample. In the present study, we confirm to measure the thermal diffusivity of bulk Si and Cu by this non-contact method with halogen-lamp irradiation. In determining the thermal diffusivity from the relationship between distance deviation and delay time, the simplest wave equation is used, and the obtained values of thermal diffusivity for Si and Cu are close to those reported. Therefore, this non-contact method is useful for evaluating the thermal conduction and applicable for nanometer-scaled materials by improving local heating and local detecting systems.
Energy and Exergy Analysis of Kalina Cycle for the Utilization of Waste Heat in Brine Water for Indonesian Geothermal Field Nasruddin, Nasruddin; Noor Sidiq, Agus; Mohamad, Abdulmajeed; Usvika, Rama
Makara Journal of Technology Vol 19, No 1 (2015)
Publisher : Directorate of Research and Community Services, Universitas Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.7454/mst.v19i1.3032

Abstract

The utilization of waste heat in a power plant system—which would otherwise be released back to the environment—in order to produce additional power increases the efficiency of the system itself. The purpose of this study is to present an energy and exergy analysis of Kalina Cycle System (KCS) 11, which is proposed to be utilized to generate additional electric power from the waste heat contained in geothermal brine water available in the Lahendong Geothermal power plant site in North Sulawesi, Indonesia. A modeling application on energy and exergy system is used to study the design of thermal system which uses KCS 11. To obtain the maximum power output and maximum efficiency, the system is optimized based on the mass fraction of working fluid (ammonia-water), as well as based on the turbine exhaust pressure. The result of the simulation is the optimum theoretical performance of KCS 11, which has the highest possible power output and efficiency. The energy flow diagram and exergy diagram (Grassman diagram) was also presented for KCS 11 optimum system to give quantitative information regarding energy flow from the heat source to system components and the proportion of the exergy input dissipated in the various system components.
Group Decisions in Value Management Utomo, Christiono; Murti, Farida; Idrus, Arazi
Makara Journal of Technology Vol 19, No 1 (2015)
Publisher : Directorate of Research and Community Services, Universitas Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.7454/mst.v19i1.3025

Abstract

This research deals with a technique to expedite group decision making during the selection of technical solutions for value management process. Selection of a solution from a set of alternatives is facilitated by evaluating using multicriteria decision making techniques. During the process, every possible solution is rated on criteria of function and cost. Function deals more with quality than with quantity, and cost can be calculated based on the theoretical time value of money. Decision-making techniques based on satisfying games are applied to determine the relative function and cost of solutions and hence their relative value. The functions were determined by function analysis system technique. Analytical hierarchy process was applied to decision making and life-cycle cost analysis were used to calculate cost. Cooperative decision making was shown to consist of identifying agreement options, analyzing, and forming coalitions. The objective was attained using the satisfying game model as a basis for two main preferences. The model will improve the value of decision regarding design. It further emphasizes the importance of performance evaluation in the design process and value analysis. The result of the implementation, when applied to the selection of a building wall system, demonstrates a process of selecting the most valuable technical solution as the best-fit option for all decision makers. This work is relevant to group decision making and negotiation, as it aims to provide a framework to support negotiation in design activity.
Phonon-drag Contribution to Seebeck Coefficient of Ge-on-insulator Substrate Fabricated by Wafer Bonding Process Manimuthu, Veerappan; Yoshida, Shoma; Suzuki, Yuhei; Salleh, Faiz; Arivanandhan, Mukannan; Kamakura, Yoshinari; Hayakawa, Yasuhiro; Ikeda, Hiroya
Makara Journal of Technology Vol 19, No 1 (2015)
Publisher : Directorate of Research and Community Services, Universitas Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.7454/mst.v19i1.3026

Abstract

In order to build high-sensitivity infrared photodetectors using SiGe nanowires, we investigate the thermoelectric characteristics of Ge-on-insulator (GOI) layers as a reference for SiGe. We fabricate p-type GOI substrates with an impurity concentration of 1016-1018cm-3 by a wafer-bonding process using Ge and oxidized Si wafers. Annealing treatment is performed in order to further increase the bonding strength of Ge/SiO2 interface. We measure the Seebeck coefficient in the temperature range of 290-350 K. The Seebeck coefficient of the GOI layers is very close to the theoretical value for Ge, calculated on the basis of carrier transport. Hence, there is a small phonon-drag effect in GOI. On the other hand, the effect of phonon drag on the Seebeck coefficient of Si is usually significant. These results likely stem from the differences between phonon velocity, phonon mean-free-path, and hole mobility between Ge and Si.
Seebeck Coefficient of SOI Layer Induced by Phonon Transport Salleh, Faiz; Oda, Takuro; Suzuki, Yuhei; Kamakura, Yoshinari; Ikeda, Hiroya
Makara Journal of Technology Vol 19, No 1 (2015)
Publisher : Directorate of Research and Community Services, Universitas Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.7454/mst.v19i1.3022

Abstract

The Seebeck coefficient of a patterned Si wire on P-doped SOI (Si-on-insulator) layer with a carrier concentration of 1018 cm-3 was measured near room temperature. The Seebeck coefficient is found to be smaller than that in the SOI layer and to be closer to the calculated Seebeck coefficient including the electronic contribution. The decrease in the Seebeck coefficient of Si wire is likely to occur due to the elimination of the contribution of phonon drag part. From the theoretical calculation of scattering rates by considering the scattering processes in phonon system, it is considered that an increase in phonon-boundary scattering and simultaneously a decrease at the cross section of SOI layer are likely responsible for eliminating the phonon drag effect.

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