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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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Corrosion Rate of Carbon Steel For Flowline and Pipeline as Transmission Pipe in Natural Gas Production with Co2 Content Rustandi, Andi; Adyutatama, Muhammad; Fadly, Enriko; Subekti, Norman
Makara Journal of Technology Vol. 16, No. 1
Publisher : UI Scholars Hub

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Abstract

The purpose of this research is to investigate the corrosion rate of carbon steel as flowline and pipeline in natural gas production with CO2 content. The influence of variety of conditions that represent the actual conditions in practice such as CO2 partial pressure and solution composition, particularly NaCl percentage were performed. Research conducted by polarization test and simulation methods using PREDICTTM software. The result of this research is used to illustrate the level of corrosion rate of typical carbon steel i.e. API 5L X-52 occurred in natural gas pipelines due to the effect of dissolved CO2. From the experiments obtained that corrosion rate of steel in environments containing CO2 ranged between 15-28 mpy. This high corrosion rate observed could severely damage natural gas transmission flowline and pipeline. The result of this research is the first step, as an input for prevention efforts, to prevent leakage of flowline and pipeline due to corrosion of CO2 which appropriate with the lifetime that has been designed.
Pineapple Liquid Waste as Nata De Pina Raw Material Sutanto, Agus
Makara Journal of Technology Vol. 16, No. 1
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Abstract

This research aims to study the quantity, quality, ecological and economic feasibility of nata de pina production (NP) from pineapple liquid waste (PLW). The design of the study employs complete random design (CRD) with three treatments: PLW without nutrients addition (A), PLW nutrients addition (B), and PLW stored for six months with nutrients addition (C). The nata de pina’s production factors measured were weight, thickness, fiber content, color, brightness, and residual waste. The highest weight was reached in treatment B (899 grams), followed by treatment A (616.4 grams), and C (477.8 grams). The thickness of NP of the height and low as in treatment B (1.58 cm) followed by treatment A (1.24 cm) and C (0.88 cm), respectively. The highest fiber content was found in treatment C (9.3%) followed by treatment B (7.6%) and A (6.9%), respectively. The fiber content, along with color quality and brightness fit with food standards. The production of NP may reduce the volume of the PLW from 46.2% to 89.1% (p =0.001). Based on the standard value of biological oxygen demand (BOD), chemical oxygen demand (COD), total suspended solid (TSS) below to the required threshold except pH. The production of NP is economically feasible to 4.7 BC ratio. The overal manufacture of nata de pina from PLW produces better and feasible product ecologically and economically
Circularly Polarized Microstrip Array Antenna for Ground Segment in Quasi-Zenith Satellite System Zulkifli, Fitri Yuli; Rahardjo, Eko Tjipto
Makara Journal of Technology Vol. 16, No. 1
Publisher : UI Scholars Hub

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Abstract

In satellite communication system, antenna plays an important role. Therefore, the antenna must meet some requirements, such as high gain, circular polarization, and good directivity. In this paper, a four element linear array triangular patch microstrip antenna with cross slot is designed to be used for Quasi-Zenith satellite system. A simulation study as well as experimental study was carried out. The simulation showed that the 3 dB axial ratio bandwidth of 87 MHz (2.569-2.656 GHz) is achieved while the measured results showed 96 MHz (2.556-2.652 GHz). The linear array of 4 element antenna has a gain of 13.73 dB and maximum radiation pattern at 40° and -40°. Simulation and experiment results show that this antenna has met the characteristic requirements of Quasi-Zenith satellite.
Modeling of a New Structure of Precision Air Conditioning System Using Secondary Condenser for Rh Regulation Subiantoro, Aries; Nasruddin, Nasruddin; Yusivar, Feri; Al-Hamid, Muhammad Idrus; Budiardjo, Bagio
Makara Journal of Technology Vol. 16, No. 1
Publisher : UI Scholars Hub

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Abstract

A dynamic mathematical model for a new structure of precision air conditioning (PAC) has been developed. The proposed PAC uses an additional secondary condenser for relative humidity regulation compared to a basic refrigeration system. The work mechanism for this system and a vapour-compression cycle process of the system are illustrated using psychrometric chart and pressure-enthalpy diagram. A non-linear system model is derived based on the conservation of mass and energy balance principles and then linearized at steady state operating point for developing a 8th-order state space model suited for multivariable controller design. The quality of linearized model is analyzed in terms of transient response, controllability, observability, and interaction between input-output variables. The developed model is verified through simulation showing its ability for imitating the nonlinear behavior and the interaction of input-output variables.
Optimizing Fermentation Medium to Produce Cyclosporin a Using Response Surface Methodology Sunaryanto, Rofiq
Makara Journal of Technology Vol. 16, No. 1
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Abstract

Response surface methodology (RSM) is a three factorial model which illustrates the relationship between one or more independent variables. RSM can be used to optimize the fermentation medium for the production of Cyclosporin A from the isolate Tolypocladium inflatum. The optimal point of the response surface area is predicted by using a seconddegree polynomial model and applying the statistic model obtained from the central composite design (CCD). The results of optimizing the fermentation medium for Cyclopsorin using the three independent variables of glucose, casein, and KH2PO4 show that all three of the independent variables affect the production of Cyclosporin A. There is a positive interaction between the independent variables of glucose and casein, however, there is no visible interaction between glucose with KH2PO4 and casein with KH2PO4. By using the mathematical model the total optimum result obtained is 1230.5 mg L-1, glucose concentrate 28.5 g L-1, KH2PO4 concentrate 0.74 gL-1, and casein concentrate 9.8 g L-1. Laboratory validation shows that Cyclosporin A productivity is 1197.285 mg L-1. There is a value difference of 2.7% between the expected productivity of Cyclosporin A using the mathematical model and the actual production in laboratory tests.
Earthquake Damage Intensity Relationship for Residential Houses in West Sumatra Ismail, Febrin Anas; Hakam, Abdul; Fauzan, Fauzan
Makara Journal of Technology Vol. 16, No. 1
Publisher : UI Scholars Hub

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Abstract

The Sumatra 30 September 2009 earthquake has damaged hundred thousand buildings in West Sumatra Province. The earthquake is located in 100 km offshore of Padang City, the Capital City of the province. Survey has been conducted to assess the damage of the building in few days after the earthquake. In this survey, the damage of buildings are categorised into 3 level that are heavily, moderate and slightly damages. This paper explores the level damage of building and then the intensity of the shaking in the affected area. Then based on the coordinate of every building location, the buildings are scattered in a map together with the intensity level. The relationship between the damage level and intensity for West Sumatra then is developed. This special damage-intensity relation is very important to be used for predicting the damage level due to a specified earthquake. The damage level is needed by The Government to develop an emergency and reconstruction budget plan for earthquake disaster in future.
Tolerance Limit for Trucks with Excess Load in Transport Regulation in Indonesia Hadiwardoyo, Sigit Pranowo; Sumabrata, Raden Jachrizal; Berawi, Mohammed Ali
Makara Journal of Technology Vol. 16, No. 1
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Abstract

Reliability of a road is mandatory since damaged will impede the traffic. Destruction is caused by various factors; one of the most important factors is excess load. Overload may give the load of each axle of a vehicle exceeds the determined standard. This condition occurs in trucks exceeding the load limit. In designing the structure of a road based on the method of Directorate General of Highways Ministry of Public Works of the Republic of Indonesia, axle load calculated in equivalent-number, or known as equivalent axle load (EAL), of 8.16 tons of standard axle. Total equivalent-number over the service life is defined as cumulative equivalent standard axle load (CESA). Due to traffic volume exceeding the volume forecast or, in other words there is an excessive load of traffic, it will make CESA achieved faster than planned. This excessive load in Indonesia, however, has been considered as a factor of environmental condition, so there is a need to introduce a correction factor for EAL as high as 20-25% in the process of designing flexible and rigid pavement so as to reduce early damage.
Small Scale Experiment: Thermal Performance Comparison Between Fiber-Cement Roof and Photovoltaic Roof In Malang, Indonesia Bonifacius, Nurhamdoko; Ekasiwi, Sri Nastiti Nugrahani
Makara Journal of Technology
Publisher : UI Scholars Hub

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Irradiation on the surface of photovoltaic module heats up the photovoltaic module itself and the room underneath the roof of integrated photovoltaic building in the tropics area. Room heating reduces thermal condition and photovoltaic module surface heating reduces its performance in generating electricity. This paper discusses an experiment of measuring the surface temperature of photovoltaic modules and fiber-cement roof surface as a comparison. This experiment also measures the impact of rising temperatures in each space underneath. It used small-scale mock-ups exposed to direct sunlight. The result of the experiment shows that photovoltaic roof surface temperature is lower than fiber-cement roof temperature. The temperature of room under photovoltaic roof is also lower than the one under fibercement roof. Empirical calculation shows that loss of electrical power found is only up to 1.7%.
Effects of Deposition Parameters and Oxygen Addition on Properties of Sputtered Indium Tin Oxide Films Munir, Badrul; Wibowo, Rachmat Adhi; Ho, Kim Kyoo
Makara Journal of Technology Vol. 16, No. 2
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Indium tin oxide (ITO) films were sputtered on corning glass substrate. Oxygen admixture and sputtering deposition parameters were optimized to obtain the highest transparency as well as lowest resistivity. Structural, electrical and optical properties of the films were then examined. Increasing deposition rate and film thickness changed the crystallographic orientation from (222) to (400) and (440), as well as higher surface roughness. It was necessary to apply substrate heating during reposition to get films with better crystallinity. The lowest resistivity of 5.36 x 10-4 Ω•cm was obtained at 750 nm film thickness. The films’ resistivity was increased by addition of oxygen up to 2% in the argon sputtering gas. All films showed over 85% transmittance in the visible wavelength range, possible for applications in photovoltaic and display devices.
Improved Optical Probe for Measuring Phytoplankton Suspension Concentrations Based on Optical Fluoresensce and Absorption Purnamaningsih, Retno Wigajatri; Prihantini, Nining Betawati
Makara Journal of Technology Vol. 16, No. 2
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Abstract

This paper discusses the results of improved optical probe that works according to optical fluorescence and absorption phenomena for measuring the phytoplankton suspension concentrations. Measurements are made on the Scenedesmus sp. culture. The laboratory test has shown that range of concentration from 104 up to around 1 x 106 cells/mL; fluorescence intensity at λ = 685 nm; and logarithmic of transmission intensity at λ = 405 nm are proportional to the cell concentration linear with proportional constant γ = 4 × 10-5 and β = –2 × 10-7 mL/cell respectively.

Page 21 of 49 | Total Record : 485

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