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INDONESIA
MAKARA Journal of Technology Series
Published by Universitas Indonesia
ISSN : -     EISSN : -     DOI : -
Core Subject : Science,
Computer Science & IT
Arjuna Subject : -
Articles 243 Documents
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APPLICATION OF EMPIRICAL ORTHOGONAL FUNCTION MODELS TO ANALYZE SHORELINE CHANGE AT BANGKALAN MADURA Darius Arkwright; Suntoyo Suntoyo
MAKARA Journal of Technology Vol 15, No 2 (2011): November
Publisher : Directorate of Research and Community Engagement, Universitas Indonesia

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Abstract

Bangkalan’s shoreline, especially on the opposite side of Surabaya, has been evaluated to determine the morphological changes due to wave attack, near-shore current, long-shore sediment transport and coastal configuration. This research aims to determine the dominant patterns of variation of Bangkalan’s shoreline change, expressed by Eigen-function in empirical orthogonal function (EOF) models. That was started with data collection such as oceanographic data (wave and tidal), bathymetry and topographic map and sediment data. All data was used for forecasting two-monthly shoreline. Coordinate of two-monthly shoreline was used as input of EOF model. The first Eigen mode is a profile of shoreline equilibrium. The second Eigen mode shows pivot point that separates the different behaviors, which indicates a positive balance of shoreline from the direction of the dominant force. The models execution based on 1986’s shoreline show the shoreline change significantly at some cells e.g. around Suramadu bridge (cell 1-40), Batuporon (cell 70-100), Jungdima (cell 142-170) and at Kamal port (cell 230-250). The model of shoreline change using EOF was validated with the One-line model and data of 1995’s map’s shoreline. The E.O.F. value of model RMSE, 0.02, is less than the root mean square error (RMSE) value of One-line model, 0.04, which shows that the EOF model performance better than One-line models.Keywords: Bangkalan, Eigen-function, EOF, one-line model, shoreline change
FORMATION OF CaCO3 PARTICLE AND CONDUCTIVITY OF Na2CO3 AND CaCl2 SOLUTION UNDER MAGNETIC FIELD ON DYNAMIC FLUID SYSTEM Nelson Saksono; Setijo Bismo; Roekmijati Widaningroem; Azwar Manaf
MAKARA Journal of Technology Vol 15, No 1 (2011): April
Publisher : Directorate of Research and Community Engagement, Universitas Indonesia

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Abstract

Hard water causes the CaCO3 scale formation on the pipe walls and heat exchanger equipments in industrial or domestic water processes. A great number of experimental researches on the prevention of the CaCO3 precipitation process by magnetic field have been carried out. In this research, Na2CO3 and CaCl2 solutions was magnetized in the circulated flow condition (dynamic fluid system). The velocity of fluid and the circulation time was modified to examine its influences to the magnetization process. CaCO3 content was measured by titration method of EDTA complexometry. Conductivity test was conducted to find out hydrate ion bonding. The results showed that magnetization increased the CaCO3 formation and the optimum process reaches for 10 minutes circulation on 0.554 m/s of flow rate. Magnetic field decreases the conductivities of Na2CO3 and CaCl2 solution, hence reduced the ion hydrate bonding. These results showed that magnetization on Na2CO3 and CaCl2 ionic solution was effective in controlling the CaCO3 formation by increasing CaCO3 precipitation. Keywords: CaCO3 conductivity, magnetic carbonate solution, precipitation
THE SYNERGY OF RECOMBINANT XYLANOLYTIC ENZYME ON XYLAN HYDROLYSIS One Asmarani; Bambang Wardojo; Ni Nyoman Puspaningsih
MAKARA Journal of Technology Vol 15, No 1 (2011): April
Publisher : Directorate of Research and Community Engagement, Universitas Indonesia

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Abstract

Microbial xylanases or xylanolytic enzyme have received considerable attention over the last years owing to a multitude of possible applications. These enzymes have potential in the biodegradation of lignocellulosic biomass to fuels, chemicals, fruit juice, animal feed and in improving rumen digestion. More recently, the use of xylanases as bleaching agent in the pulp and paper industry has been suggested to replace of some of the chemicals presently used for this purpose. Such applications could have an important positive impact on the environment. The purpose of this research was determining the synergy of 3 recombinant xylanolytic enzymes (β-xylosidase, exo-xylanase and α-L-arabinofuranosidase) from recombinant Eschericia coli BL21 (DE-star) in xylan hydrolysis by analysis the reduction sugar product. Purified of recombinant xylanolytic enzyme β-xylosidase (Xyl), exo-xylanase (Exo-Xyl) and α-L-arabinofuranosidase (Abfa) with Ni-NTA resin. Seven samples of enzyme (each and enzyme mixture) used to hydrolyze xylan substrate (oat-spelt xylan). Analysis of hydrolysis product was done by HPLC. The xylanolytic activities of this enzyme before and after purification were 0,91 and 9,94 U/mL (Exo-Xyl); 1,65 and 14,2 U/mL (Xyl); 0,65 and 5,6 U/mL (Abfa). The xylosidase activity were 2,37 and 14,3 U/mL (Xyl); 1,49 and 10,5 U/mL (Exo-Xyl); 2,54 and 18,6 U/mL (Abfa). The highest hydrolysis product of xylan (xylose) shown in enzyme mixture of exo-xylanase and β-xylosidase was 1,084 mg/mL. Keywords: α-L-arabinofuranosidase, β-xylosidase, exo-xylanase, xylan, xylose
KARAKTERISTIK MEKANIK KOMPOSIT LAMINA SERAT RAMI EPOKSI SEBAGAI BAHAN ALTERNATIF SOKET PROSTESIS Tresna Soemardi; Widjajalaksmi Kusumaningsih; Agustinus Irawan
MAKARA Journal of Technology Vol 13, No 2 (2009): November
Publisher : Directorate of Research and Community Engagement, Universitas Indonesia

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Abstract

Mechanical properties of ramie fiber reinforced epoxy lamina composite for socket prosthesis. This paper presentsan investigation into the application of natural fiber composite especially ramie fiber reinforced epoxy laminacomposite for socket prosthesis. The research focuses on the tensile and shear strength from ramie fiber reinforcedepoxy lamina composite which will be applied as alternative material for socket prosthesis. The research based onAmerican Society for Testing Material (ASTM) standard D 3039/D 3039M for tensile strength and ASTM D 4255/D4255M-83 for shear strength. The ramie fiber applied is a fiber continue 100 % Ne14'S with Epoxy Resin Bakelite EPR174 as matrix and Epoxy Hardener V-140 as hardener. The sample composite test made by hand lay up method.Multiaxial characteristic from ramie fiber reinforced epoxy composite will be compared with ISO standard forplastic/polymer for health application and refers strength of material application at Prosthetics and Orthotics. Theanalysis was completed with the mode of the failure and the failure criterion observation by using Scanning ElectronMicroscope (SEM). Based on results of the research could be concluded that ramie fiber reinforced epoxy compositecould be developed further as the alternative material for socket prosthesis on Vf 40-50%. Results of the research willbe discussed in more detail in this paper.Keywords: mechanical properties, ramie fiber reinforced epoxy lamina composite, socket prosthesis
STUDI LAPISAN INTERMETALIK Cu3Sn PADA UJUNG ELEKTRODA DALAM PENGELASAN TITIK BAJA GALVANIS Muhammad Anis; Aulia Irsyadi; Deni Ferdian
MAKARA Journal of Technology Vol 13, No 2 (2009): November
Publisher : Directorate of Research and Community Engagement, Universitas Indonesia

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Abstract

Intermetallic 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 welding
PERFORMANCE OF HOLLOW FIBER MEMBRANE GAS-LIQUID CONTACTORS TO ABSORB CO2 USING DIETHANOLAMINE (DEA) AS A SOLVENT Sutrasno Kartohardjono; Pan Nata; Eko Prasetio; Yuliusman Yuliusman
MAKARA Journal of Technology Vol 13, No 2 (2009): November
Publisher : Directorate of Research and Community Engagement, Universitas Indonesia

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Abstract

This 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 contactor
PEMODELAN DAN SIMULASI KATALITIK KONVERTER PACKED BED UNTUK MENGOKSIDASI JELAGA PADA GAS BUANG KENDARAAN BERMESIN DIESEL Mohammad Nasikin; Praswasti Wulan; Vita Andrianty
MAKARA Journal of Technology Vol 8, No 3 (2004): Desember
Publisher : Directorate of Research and Community Engagement, Universitas Indonesia

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Abstract

Modelling and Simulation of Packed Bed Catalytic Converter for Oxidation of Soot in Diesel Powered VehiclesFlue Gas. Diesel vehicle is used in Indonesia in very big number. This vehicle exhausts pollutants especially diesel sootthat can be reduces by using a catalytic converter to convert the soot to CO2. To obtain the optimal dimension ofcatalytic converter it is needed a model that can represent the profile of soot weight, temperature and pressure along thecatalytic converter. In this study, a model is developed for packed bed catalytic converter in an adiabatic conditionbased on a kinetic study that has been reported previously. Calculation of developed equations in this model usesPolymath 5.X solver with Range Kutta Method. The simulation result shows that temperature profile along catalyticconverter increases with the decrease of soot weight, while pressure profile decreases. The increase of soot weight inentering gas increases the needed converter length. On the other hand, the increase of catalyst diameter does not affectto soot weight along converter and temperature profile, but results a less pressure drop. For 2.500 c diesel engine,packed bed catalytic converter with ellipse's cross sectional of 14,5X7,5 cm diagonal and 0,8 cm catalyst particlediameter, needs 4,1 cm length.Keywords: catalytic converter, soot, diesel engine
SISTEM INJEKSI BAHAN BAKAR SEPEDA MOTOR SATU SILINDER EMPAT LANGKAH Bambang Sugiarto
MAKARA Journal of Technology Vol 8, No 3 (2004): Desember
Publisher : Directorate of Research and Community Engagement, Universitas Indonesia

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Abstract

Fuel Injection System for One Cylinder Motor Cycle Engine. Fuel injection has been developed for many years. Butits common application is limited on car's engine. With many reason fuel injection systems in motorcycle one cylinderengine has not been widely used yet. Fuel Injection System allows the amount of fuel, injected to be controlledappropriate to engine parameters such as engine speed, amount of air inducted to cylinder, temperature, for each cycle,over the entire engine operating conditions. This fuel injection research is done to find out the Volumetric Efficiency ofthe intake manifold system, the amount of fuel need to be injected for each engine cycle, and the engine characteristicsover variation of test conditions. This research based on Honda CB100 engine, at applied thermodynamic Laboratory ofMechanical Engineering Department, Faculty of Engineering University of Indonesia. Experiment data from thisresearch shows the characteristics of injector duration as functions of engine speed, intake pressure, on one cylinderengine and the results of this research shows a good Volumetric Efficiency of the intake manifold designed using CFD(Computational Fluid Dynamic).Keywords: fuel injection system for motor cycle,intake manifold, computational fluid dynamic
PENGARUH DEBIT INFLUEN TERHADAP KARAKTERISTIK HIDRODINAMIKA KOLAM FAKULTATIF BOJONGSOANG: TANPA PENGARUH ANGIN Rositayanti Hadisoebroto; Suprihanto Notodarmojo
MAKARA Journal of Technology Vol 8, No 3 (2004): Desember
Publisher : Directorate of Research and Community Engagement, Universitas Indonesia

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Abstract

The Effects of Influent Debit on Hydrodynamic Characteristic of Bojongsoang Facultative Pond: Without WindEffects. The performance of facultative pond in Bojongsoang WWTP have reported to be unstable. One of the cause ofthe unstable performance is the hydrodynamic characteristics that not met the criterion. The improper hydrodynamiccharacteristics are included the existence of dead-zone, the short-circuiting, and the turbulence due to eddy current. Thestudy was to analyze the effect of the influent debit variation on the hydrodynamic characteristics of the pond usingmathematical model. The two-dimensional hydrodynamic model was built from two hydrodynamic equations which arecontinuity and momentum equations. The equations were solved by finite-difference numerical method of semi-implicit(Crank-Nicolson). From the simulation results, the Froude number of the water flow was analyzed. Beside that, theeffective residence time and the effective area were calculated. All of them were done to analyzed the existence of thedead-zone in the pond. The simulation results show that the dead-zone was exist in the center of the pond. when theinfluent debit was larger, the effective residence time and the effective area become larger. The distribution of theFroude number value shows that the area with the value of 10-10 become reduced in the larger influent debit. Theexistence of the dead-zone was reduced since the influent debit become larger. It can be said that the larger influentdebit can improve the hydrodynamic characteristics of the pond.Keywords: dead-zone, facultative pond, Froude number, hydrodynamic characteristics, influent debit
PENGARUH PENEMPATAN PENYAMBUNGAN PADA PERILAKU RANGKAIAN BALOK-KOLOM BETON PRACETAK BAGIAN SISI LUAR Elly Tjahjono; Heru Purnomo
MAKARA Journal of Technology Vol 8, No 3 (2004): Desember
Publisher : Directorate of Research and Community Engagement, Universitas Indonesia

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Abstract

Influence of Connection Placement to the Behavior of Precast Concrete Exterior Beam-Column Joint. This paperpresents an experimental study on the influence of connection placement to the behaviour of exterior beamcolumnjoint of precast concrete structure under semi cyclic loading. Four half-scale beam-column specimens wereinvestigated. Three beam-columns were jointed through connection that are placed in beam-column joint region and theforth is connected at the plastic hinge potensial region of the beam. Crack patterns, strength, stiffness and ductility ofthe test specimens have been evaluated. The test result indicated that all beam-column specimens show good ductilitybehavior.Keywords: precast concrete, beam-column joint, reinforced concrete

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