MAKARA Journal of Technology
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SINTESIS DIBENZIL TEREFTALAT MELALUI DEPOLIMERISASI PLASTIK POLI(ETILENA TEREFTALATE) SEBAGAI ALTERNATIF DAUR ULANG PLASTIK BEKAS
Get PDFSynthesis Dibenzyl Terephthalate Through Depolimerization of Poly(ethylene terephthalate) as Alternative ofWaste Plastics Recycling. Synthesis dibenzyl terephathalate were done through PET degradation by refluxing inbenzyl alcohol at 145oC temperature for 20, 24, and 28 hours in the presence of zinc acetate catalyst. The result ofdegradation was purified by recristalization in methanol and then melting point (mp), FTIR, 1H NMR spectra, and TLCspot were determined. The melting point of product degradation for 28 hours was 98-99 oC. Based FTIR spectra knownthat compunds of product degradation have OH, C=O, C-O, CH, monosubstituted benzene, disubstituted benzenegroups, while on 1H NMR spectra showed chemical shift at 8.2 ppm (s, 10 H of monosubtituted benzene), 7.5 ppm (s, 9H consist of 4 H disubstituted benzene and 5 H of aromatic benzyl alcohol), 5.4 ppm (s, 1 H from OH benzyl alcohol),4.8 ppm (s, 4 H of methylene), and 2.9 ppm (s, 7 H of other traces). The single spot of TLC plate indicated that productdegradation for 28 hours might be a single compund. Based these characterization concluded that compound of productdegradation was dibenzyl terephthalate contains benzyl alcohol and other traces.Keywords: degradation, poly(ethylene terephthalate), dibenzyl terephthalate, softdrink bottle
PRODUCTION HYDROGEN AND NANOCARBON VIA METHANE DECOMPOSITION USING Ni-BASED CATALYSTS. EFFECT OF ACIDITY AND CATALYST DIAMETER
Get PDFObjectives of this research are mainly to study impacts of acidity strength (by varying amount of precipitant and loadingAl-Si) and the effect of nickel particle size (by varying calcinations temperature) on decomposition reactionperformances. In this research, high-nickel-loaded catalyst is prepared with two methods. Ni-Cu/Al catalysts wereprepared with co-precipitation method. While the Ni-Cu/Al-Si catalyst were prepared by combined co-precipitation andsol-gel method. The direct cracking of methane was performed in 8mm quartz fixed bed reactor at atmospheric pressureand 500-700°C. The main results showed that the Al content of catalyst increases with the increasing amount ofprecipitant. The activity of catalyst increases with the increasing of catalyst's acidity to the best possible point, and thenincreasing of acidity will reduce the activity of catalyst. Ni-Cu/4Al and Ni-Cu/11Al deactivated in a very short timehence produced fewer amount of nanocarbon, while Ni-Cu/15Al was active in a very long period. The most effectivecatalyst is Ni-Cu/22Al, which produced the biggest amount of nanocarbon (4.15 g C/g catalyst). Ni catalyst diameterhas significant effect on reaction performances mainly methane conversion and product yield. A small Ni crystal sizegave a high methane conversion, a fast deactivation and a low carbon yield. Large Ni particle diameter yielded a slowdecomposition and low methane conversion. The highest methane conversion was produced by catalyst diameter of 4nm and maximum yield of carbon of 4.08 g C/ g catalyst was achieved by 15.5 nm diameter of Ni catalyst.Keywords: carbon nanotube, hydrogen, methane decomposition, nickel based catalys
MODIFIKASI PENGUJIAN KEKUATAN LEKAT LAPISAN HVOF THERMAL SPRAY DENGAN SERBUK WC PADA NOSEL ROKET
Get PDFModification of Bonding Strength Test of WC HVOF Thermal Spray Coating on Rocket Nozzle. One way toreduce structural weight of RX-100 rocket is by modifying the nozzle material and processing. Nozzle is the main targetin weight reduction due to the fact that it contributes 30 % to the total weight of the structur. An alternative for this is bysubstitution of massive graphite, which is currently used as thermal protector in the nozzle, with thin layer of HVOF(High Velocity Oxy-Fuel) thermal spray layer. This paper presents the characterization of nozzle base material as wellas the modification of bonding strength test, by designing additional jig to facilitate testing processes while maintaininglevel of test accuracy. The results showed that the material used for RX-100 rocket nozzle is confirmed to be S45Csteel. Modification of the bonding strength test was conducted by utilizing chains, which improve test flexibility andmaintains level of accuracy of the test.Keywords: thermal spray, WC, bonding strength test
PERANCANGAN PUTARAN MOTOR INDUKSI TIGA PHASA TANPA SENSOR KECEPATAN DENGAN PENGENDALI VEKTOR ARUS DAN FULL DAN REDUCED OBSERVER BERADA PADA SUMBU DQ
Get PDFDesign of Induction Motor Drive Without Velocity Sensor Using Current Vector Controller with Full andReduced Observer Moving to DQ Axis. The observer is used in estimation velocity sensor usually in α-β axis,therefore this situation will need an extra transformation when we want to add compensator because the flux model is indirect and quadrature-axis dq. Every used the transformation to make possible emerge an error. So in this simulation isused a method to estimate the velocity of induction motor drive with observer that is moved to dq-axis. The model ofactual motor used is in alfa-beta axis, but the observer use the motor models in rotor flux oriented control (RFOC).Thismatter, also to prove that the different models of motor drives can be used between the actual and estimated one. Thesimulation results with C-MEX S-function Matlab/Simulink 6.5 to show that the full order observer in dq axis gives better performance than the reduced order observer.Keywords: current vector, induction motor, controlle
DETERMINATION OF OPERATION CONDITION AND PRODUCT DIMENSION ACCURACY OPTIMIZATION OF FILAMENT DEPOSITION MODELLING ON LAYER MANUFACTURING APPLICATION
Get PDFLayer manufacturing process has proven as a process that can produce a high complexity mechanical part.Now, Improvement of LM methods continuously conduct that is aimed to increase precessions and efficiency of theseprocesses. Pressure filament deposition modelling is a form of layer manufacturing process that is designed to produce aplastic part with controlling its semisolid phase. In this research, the equipment of filament depositor is designed andtested to make the product filament deposition. With operation condition observation, the optimal temperature andpressure of deposition process was determined. These experiments used PVC as crystalline material and polypropyleneas amorphous material. To optimize this process, the tensile strength and density test were conducted. The shape oftensile test specimens is based on ASTM 638 standard and made in 3 orientations deposition path, namely: in 0 degree,45 degree and 90 degree from load force axis. To found the most accurate dimension, controlling the time delay,temperature of build part, feeding speed and variation deposition path was conducted. The results of experiments showthat the filament deposition method can only be applied for amorphous material in which it has a semisolid phase. Fromthe tensile strength test, the binding strength among filaments is 0.5 kg/mm2, 20% of the tensile strength of filament.And the density of a sample product, which used the filament diameter of 0.8 mm, is 0.7668 g/cm3. Accuracy of productdimension can be increased by: controlling time delay in location where the motion orientation of hopper filament ischanged and controlling temperature of build part surface.Keywords: semi solid phase, deposition, filament flow-rat
A SIMPLE TECHNIQUE FOR SURFACE AREA DETERMINATION THROUGH SUPERCRITICAL CO2 ADSORPTION
Get PDFThe measurement of specific surface area of porous materials has long been important in physical sciences and iscurrently growing in importance in applied and environmental science. Numerous systems have been developed forsurface area measurement by gas adsorption. Commercial systems are available which can measure a wide range ofabsolute surface area with relative ease. However, their cost is often prohibitive. In this study, an inexpensive apparatusfor surface area measurement has been set up to be used for measuring supercritical adsorption of CO2. The Ono-KondoLattice model was used to represent the adsorption isotherm and to determine the surface area. The results of surfacearea determination using CO2 adsorption combined with OK model have been compared to the numbers obtained fromnitrogen BET method. For surface area determination of zeolites and activated carbons, the new method give reasonableagreement results (within 10% deviation) compared to the results obtained from nitrogen BET method. In addition, thenew method also gives more reasonable results for surface area determination of coals. As known, the nitrogen BETmethod gives almost zero of coals’ surface area. This might due to the characteristic of the coals’ structure that might bechange (the pores are closed) during the cooling process in nitrogen BET method. Moreover, the new method can alsobe used to determine the surface area of porous materials using CO2 adsorption data at various temperatures withoutsacrificing their accuracy.Keywords: adsorption, carbondioxide, surface are
PENGEMBANGAN ANTENA MIKROSTRIP SUSUN DUA ELEMEN DENGAN PENERAPAN DEFECTED GROUND STRUCTURE BERBENTUK TRAPESIUM
Get PDFTwo Element Microstrip Antenna Array with Defected Ground Structure. This paper presents a two elementmicrostrip antenna array using trapezium shape defected ground structure (DGS). The DGS is inserted in the groundplane between two elements of antenna array. Insertion of the DGS is intended to suppress the mutual coupling effectproduced by antenna array. Simulation and measurement results were taken and compared between antenna array withand without DGS. Measurement results show that the antenna with DGS compared to antenna without DGS cansuppress mutual coupling effect to 7.9 dB, improve the return loss to 33.29% from -30.188 dB to -40.24 dB and axialratio bandwidth enhancement to 10 MHz. This bandwidth enhancement is achieved from frequency 2.63 GHz – 2.67GHz for antenna without DGS and from frequency 2.63 GHz – 2.68 GHz for antenna with DGS. In addition, the DGSantenna also improved the antenna gain to 0.6 dB. The results show that the implementation of the trapezium DGS canimprove the radiation properties of the antenna without DGS.Keywords: defected ground structure, microstrip antenna array, trapezium, mutual couplin
POTENSI BAHAYA KEBAKARAN DAN LEDAKAN PADA TANGKI TIMBUN BAHAN BAKAR MINYAK (BBM) JENIS PREMIUM DI DEPOT X TAHUN 2007
Get PDFThe Potency of Fire and Explosion Hazard on Premium Oil Storage Tank at Depot X 2007. Premium oil storagetanks have fire and explosion risk because Premium oil is flammable liquid. Because of that, fire and explosion riskassessment on Premium oil storage tank at Depot X is needed as foundation to fire and explosion risk management, andcomply with regulations. Method of this research is Dow’s Fire and Explosion Index. This research indicate that F&EIvalue for Premium oil storage tank is 118,82. Based on that F&EI value, level of risk at Premium oil storage tank isintermediate risk.Keywords: fire, explosion, Dow’s Index, storage tank, Premiu
SISTEM KENDALI HYBRID PID - LOGIKA FUZZY PADA PENGATURAN KECEPATAN MOTOR DC
Get PDFPID Fuzzy Logic Controller System for DC Motor Speed Control. A good controller system must have resilience todisturbance and must be able to response quickly and accurately. Problem usually appears when PID controller systemwas built sensitively hence the system's respon to the disturbance will yield big overshot/undershot then the possibilityof oscillation to be happened is excelsior. When the controller system was built insensitively, the overshot/undershotwill be small but the recovery time will be longer. Hybrid controller system could overcome those problems bycombining PID control system with fuzzy logic. The main control of this system is PID controller while the fuzzy logicacts to reduce an overshot/undershot and a recovery time. The fuzzy logic controller is designed with two input errorand delta error and one output of the motor speed. The output of fuzzy logic controller should be only half of the PIDcontroller for limiting entirely fuzzy output. This hybrid system design has a better respon time controller system thanPID controller without fuzzy logic.Keywords: hybrid PID - fuzzy, disturbanc
PEMBUATAN PETA STRUKTUR-KEDALAMAN SHELF-EDGE FORMASI KUJUNG, LAUT JAWA TIMUR
Get PDFConstruction of Depth-Structure Shelf-edge Map for Case Study of Kujung Formation, East Java Sea. In general,reflection seismic method has capability to represent sub-surface in time domain. Seismic cross-section that depicts theformation of sub-surface usually use time domain in the format of TWT (Two Way Times). This due to in the processof seismic data acquisition, seismic wave propagates in down-going and up-going manner so that the obtained resultsfrom data processing are in the format of TWT seismic vs. shot points. This paper will describe the construction ofdepth-structure map for case study of Kujung Formation, East Java Sea, as exploration activities of oil companies inIndonesia. Manual data is peaked from seismic cross section and crossed with Vrms data of 3 wells in explorationlocation. TWT Shelf-edge map of Kujung Formation is divided into 2 parts and the results is crossed with velocitystructuremap using Geoframe software CPS-3 so that depth-structure of shelf-edge of Kujung Formation, East JavaSea, is obtained. One of the objectives of this map construction is to get more real visualization of sub surface by usingdepth domain approach and as sustainable exploration activities of oil companies in Indonesia.Keywords: shelf-edge, peak, seismic cross