MAKARA Journal of Technology
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STUDI LAPISAN INTERMETALIK Cu3Sn PADA UJUNG ELEKTRODA DALAM PENGELASAN TITIK BAJA GALVANIS
Get PDFIntermetallic Cu3Sn Phase Layer on Electrode’s Tip of Galvanized Resistance Spot Welding. A resistance spotwelding method is commonly used in automotive industries application. In a resistance spot welding method, the copperelectrode has a significant role as an electric current carrier for joining thin metal sheet. This research was focused onstudying the effect of tin layer at the electrode tip for joining galvanized steel sheet. The main variable of this researchis in the thickness of the intermetallic Cu3Sn layer. The result showed that the introduction of tin layer less than 1 μm inthickness on the electrode tip gives a comparable shear strength and nugget diameter distribution with the unplatedelectrode tip.Keywords: intermetallic Cu3Sn, shear strength and nugget diameter, spot weldin
IMPROVED PREDICTIVE POWER CONTROL OF CDMA SYSTEM IN RAYLEIGH FADING CHANNEL
Get PDFIn this paper an improved prediction-based power control is proposed for code division multiple access (CDMA)systems in Rayleigh fading channel environments. One of the most serious problems which degrades the performanceof power control algorithm is the effect of feedback delay. To overcome the effect of feedback delay, power controlneeds to employ prediction algorithm which utilises the correlation property of the past channel samples measurementsto predict the future sample values. In CDMA power control, however, the correlation property of channelmeasurements is destroyed because the transmit power is continuously updated for each power control interval. Theprediction algorithm in this paper uses the recursive least square (RLS) technique and an improved predictor algorithmis proposed to compensate for the channel correlation. The result shows that the performance of improved predictivepower control proposed in this paper evaluated in terms of bit error rate (BER) as a function of bit energy-tointerferencepower density ratio Eb/Io improved significantly from that of the conventional predictor.Keywords: CDMA, least mean square, power control, prediction, rayleigh fadin
ENVIRONMENTAL REMEDIATION FULL-SCALE IMPLEMENTATION: BACK TO SIMPLE MICROBIAL MASSIVE CULTURE APPROACHES
Get PDFUsing bioaugmentation and biostimulation approach for contaminated soil bioremediation were investigated andimplemented on field scale. We combine those approaches by culturing massively the petrophilic indigenousmicroorganisms from chronically contaminated soil enriched by mixed manure. Through these methods, bioremediationperformance revealed promising results in removing the petroleum hydrocarbons comparatively using metabolite byproduct such as biosurfactant, specific enzymes and other extra-cellular product which are considered as a difficult taskand will impact on cost increase.Keywords: bioremediation, environmental biotechnology, oil and gas industr
PENETAPAN RUTE DAN PERHITUNGAN KEEKONOMIAN PIPA TRANSMISI GAS MUARA BEKASI – MUARA TAWAR MELALUI JALUR LEPAS PANTAI
Get PDFMuara Bekasi – Muara Tawar Offshore Transmission Pipeline Routing and Economic Analysis. Power plantMuara Tawar will substitute the need of oil fuel to gas as form of economizing and energy conservation. The nearestsupply point to fulfill natural gas needed on Muara Bekasi. So that Power Plant Company needed to develop gaspipeline infrastructure to joining the point.The purpose of this study is to create a system of gas transmission pipelinefrom gas supply point at Muara Bekasi to Power Plant Muara Tawar trough to offshore area. Design of gas transmissionpipeline is started with technical data collection and supply-demand analyzing, continued with data analysis, ruteconstruction and result of condition operation. The standard design of this design is DnV 2000. Gas demand in PowerPlant Muara Tawar is 400 MMSCFD. From secondary data had been obtained total length of alternative route 3.7 km.Carbon Steel pipe diameter which had been used 22 inch nominal diameter. Gas supply pressure is 350 psig withpressure of demand point is setted on 500 psig. On pipeline system design the preesure before put in to compressor isaround 321.7 psig. The design on bottom stability factor is the main concern. From the design calculation the totalminimum pipe weight is 793.16 ton, whereas the design around 932.6 ton. Therefore, the pipe will be stable on bottomof sea.Keywords: gas transmission, offshore, pipe stabilit
INTEGRATING PASSENGER AND MODULO AS LEARNING TOOLS FOR COLLABORATIVE ENGINEERING EDUCATION
Get PDFoai:journal.ui.ac.id:article/5The University of Indonesia (UI), Gerhard Mercator University (GMU), the Universiti Kebangsaan Malaysia (UKM) have agreed to cooperate as partners to develop a joint bachelor (3+1) and masters (1+1) degree, and collaborate in the research fi elds of multimedia- and internet-based learning and application level active networks. This paper describes the introduction of the Offshore Project and the extending of information technology applications to the partner institutions in this international cooperation which would very much enhance the operations of the new initiative in engineering education, which could provide students in far distance with more fl exible learning environment.Keywords: Groupware in education, multimedia-and Internet-based education concep
PENGARUH KECEPATAN DAN TEMPERATUR UJI TARIK TERHADAP SIFAT MEKANIK BAJA S48C
Get PDFInfluence of Strain Rate and Temperature of Hot Tension Testing on Mechanical Properties of Medium Carbon Steel S48C. The characterization of S48C by hot tension testing was done to understanding the influence of temperature and strain rate for S48C flow stress, that close relationship with its forge ability. The hot tension testing was performed on temperatures and strain rates variation (T 850, 900, 950 0C and έ 0,01;1 s-1). The result of hot tension testing showed that increasing temperature decreases ultimate tensile strength (UTS) and flow stress of S48C. The higher decreasing of UTS is on 950 0C about 85% from room temperature condition, while the higher decreasing of flow stress has occurred on 950 0C about 31 % compare to conditions of temperature 850 0C, strain 0,23 & strain rate (έ)1 second-1 and about 27% compare to the same conditions but έ= 0,01 second-1 . For increasing strain rate from 0,01 to 1second-1 on the temperature range (850-950 0C) increases UTS about 33 - 50 % and flow stress about 46-53%.Keywords : forgeability, flowstress, temperature, strain rate, hot tensile testin
PENERAPAN METODE PENGINDERAAN JAUH DAN SISTEM INFORMASI GEOGRAFIS UNTUK ANALISA PERUBAHAN PENGGUNAAN LAHAN (Studi Kasus: Wilayah Kali Surabaya)
Get PDFApplication of Remote Sensing and Geographic Information System Methods for Land Using Difference. Landusing difference analysis has been done using remote sensing and Geographic Information System (GIS) methods.Identification of land using difference was conducted using map overlaying process of 1990s (digitized scalling1:50.000) and 1997s land using map (interpreted from Landsat TM (Thematic Mapper) Image 1997) with UTM(Universal Transverse Mercator) coordinate. Image enhancement was done through histogram equalization withsupervised classification devided into 7 classes: rice field, settlement, dry field, industry, pond, sport field and bush.Land using difference and river pollution BOD (Biological Oxygen Demand), COD (Chemical Oxygen Demand) andTSS (Total Suspended Solid) analysis were done through GIS to get database in spasial link and tabular format. Landusing difference was done based on division segment of Kali Surabaya contour as reference. The result shows thatthere were changes on land using from 1990 until 1997 that rice field reduced by 5.72 %; settlement increased by15,16 %; dry field increased by 0.54 %; industry increased by 36.67 % and bush reduced by 26.67 %. Waterpollution analysis results which was done using multiple linier regression show both BOD (determinant coefficient 56%) and TSS (determinant coefficient 65 %) are affected by difference in land using, but COD (determinant coefficient24 %) is not affected.Keywords: land use, water pollution, Landsat TM, supervised classificatio
KARAKTERISASI DOMAIN WAKTU ANTENA BOWTIE UJUNG SIRKULER 1- 2 GHZ DENGAN RESPON IMPULS TERNORMALISASI
Get PDFTime Domain Characterization of 1-2 GHz Circular-ended Bowtie Antenna Using Normalizad ImpulseResponse. Frequency domain analysis is a powerful and compact tool for characterizing the antenna parameters such asgain, radiation pattern and the impedance as a function of frequency. However, if time or space is a major concern,such as in the GPR appication, the time domain analysis would be a very important tool due to their unique capabilityfor determining the echo delay and range profile of target image. In this paper, we will describe the classical theory ofsystem characterization in time domain, and then also propose the mathematical model for characterizing the 1 - 2 GHzcircular-ended Bowtie antenna. From the measurement results, we concluded that the implemented Bowtie antenna hasgood normalized impulse response with very small ringing, so it is suitable for GPR applications.Keywords: time domain analysis, circuar ended bowtie, normalized impulse respons
PETROLEUM DEGRADATION IN SOIL BY THERMOPHILIC BACTERIA WITH BIOPILE REACTOR
Get PDFCrude oil degradation has been carried out using biopile reactor in TPH concentration of 5%, 10% and 15%. Thethermophilic microorganism used from isolation result and identification are Aeromonas salmonicida, Bacilluspantothenticus, and Stenotrophomonas maltophilia. Biodegrade of biopile reactor done by various concentration TotalPetroleum Hydrocarbon (TPH), Total Plate Count (TPC), and Volatile Suspended Solid (VSS) per day during 30 day.Biodegrade kinetic parameter calculated are m, mm, Y, Yt, Yobs, Kd, Ks from TPH concentration decision, TPC andVSS in every microorganism with t (observation time) that is 0 hour to 168 hour. Crude oil separation efficiency in abiople reactor shows that the largest separation occurs on a starting TPH concentrate of 15% which was 61.8% later onfollowed on a starting TPH concentrate of 10% and 5% which was as much as 61% and 48.4%.Keywords: biopile, crude oil, degradation, kinetic, thermophili
PERFORMANCE OF HOLLOW FIBER MEMBRANE GAS-LIQUID CONTACTORS TO ABSORB CO2 USING DIETHANOLAMINE (DEA) AS A SOLVENT
Get PDFThis study uses DEA solution to absorb CO2 from the gas flow through the hollow fiber membrane contactors. Thisstudy aims to evaluate the performance of hollow fiber membrane contactors to absorb CO2 gas using DEA solution assolvent through mass transfer and hydrodynamics studies. The use of DEA solution is to reduce the mass transferresistance in the liquid phase, and on the other side, the large contact area of the membrane surface can cover thedisadvantage of membrane contactors; additional mass transfer resistance in the membrane phase. During experiments,CO2 feed flows through the fiber lumens, while the 0.01 M DEA solution flows in the shell side of membranecontactors. Experimental results show that the mass transfer coefficients and fluxes of CO2 increase with an increase inboth water and DEA solution flow rates. Increasing the amount of fibers in the contactors will decrease the masstransfer and fluxes at the same DEA solution flow rate. Mass transfer coefficients and CO2 fluxes using DEA solutioncan achieve 28,000 and 7.6 million times greater than using water as solvent, respectively. Hydrodynamics studiesshow that the liquid pressure drops in the contactors increase with increasing liquid flow rate and number of fibers inthe contactors. The friction between water and the fibers in the contactor was more pronounced at lower velocities, andtherefore, the value of the friction factor is also higher at lower velocities.Keywords: hydrodynamics, mass transfer, membrane contacto