MAKARA Journal of Technology
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PRODUCTION OF MEDIUM CHAIN LENGTH POLYHYDROXYALKANOATES FROM OLEIC ACID USING Pseudomonas putida PGA1 BY FED BATCH CULTURE
Get PDFBacterial polyhydroxyalkanoates (PHAs) are a class of polymers currently receiving much attention because of theirpotential as renewable and biodegradable plastics. A wide variety of bacteria has been reported to produce PHAsincluding Pseudomonas strains. These strains are known as versatile medium chain length PHAs (PHAs-mcl) producersusing fatty acids as carbon source. Oleic acid was used to produce PHAs-mcl using Pseudomonas putida PGA 1 bycontinuous feeding of both nitrogen and carbon source, in a fed batch culture. During cell growth, PHAs alsoaccumulated, indicating that PHA production in this organism is growth associated. Residual cell increased until thenitrogen source was depleted. At the end of fermentation, final cell concentration, PHA content, and productivity were30.2 g/L, 44.8 % of cell dry weight, and 0.188 g/l/h, respectively.Keywords: Biodegradable plastics, medium-chain-length polyhydroxyalkanoates (PHAs-mcl), oleic acid, Pseudomonasputida PGA 1, fed batch fermentatio
STABILITAS TERMAL GALERI CLAY PADA KOMPOSIT NANO POLIPROPILENA-CLAY MONTMORILLONIT DENGAN PENGKOMPATIBEL POLIPROPILENA-g-MALEIK ANHIDIRIDA
Get PDFThermal Stability of Clay's Galleries in Polypropylene - Clay (montmorillonite) Nanocomposites using Polypropylene-g-Maleic Anhydride as Compatibilizer. Superior properties of food packaging can be achieved using nanocompositetechnology. However, fabrication of this materials are complex and expensive. Long term objectives of this research isthe synthesis of low cost polypropylene clay nanocomposites (PPCN) via a short-cut method known as ‘cascadeengineering’. Cascade engineering principle in PPCN fabrication is performed by using compatibilizer (to enable themixing of PP and clay) masterbatch, and PPCN in one pot process using melt mixer. This paper present theexperimental results using small-angle x-ray diffraction (XRD) on the thermal stability of the PPCN. Results from theXRD analysis showed that the clay was intercalated, however no significant changes were observed as a result ofvariation in mixing time. XRD patterns of the annealed PPCN showed reduction of MMT’s gallery (deintercalation)These phenomenon was probably caused by insufficient bonding and lack of compatibility between PP-g-MA andMMT.Keywords: cascade engineering, polypropylene clay nanocomposite, PP-g-MA, thermal stabilit
DEKOMPOSISI VOLATILE MATTER DARI BATUBARA TANJUNG ENIM DENGAN MENGGUNAKAN ALAT THERMOGRAVIMETRY ANALYZER (TGA)
Get PDFThe Decompositioning of Volatile-Matter of Tanjung Enim Coal by using Thermogravimetry Analyzer (TGA).Coal is a nature material which a kind of energy source. The decompotition of coal could analyze by heat treated usingthermogravimetry analyzer. The decomposition of the volatile matter for three kinds of Tanjung Enim coal could beknown. The value of activation energy that be found diference, then for Semi Anthracite, Bitumonius and SubBituminous Coal, the initial temperatures are 60.8 oC, 70.7 oC, 97.8oC, and the last temperatures are 893.8 oC, 832 oC,584.6oC.Keywords: devolatisation, coal, thermogravimetry, activation energ
TRAJECTORY SHAPING OF SURFACE-TO-SURFACE MISSILE WITH TERMINAL IMPACT ANGLE CONSTRAINT
Get PDFThis paper presents trajectory shaping of a surface-to-surface missile attacking a fixed with terminal impact angleconstraint. The missile must hit the target from above, subject to the missile dynamics and path constraints. Theproblem is reinterpreted using optimal control theory resulting in the formulation of minimum integrated altitude. Theformulation entails nonlinear, two-dimensional missile flight dynamics, boundary conditions and path constraints. Thegeneric shape of optimal trajectory is: level flight, climbing, diving; this combination of the three flight phases is calledthe bunt manoeuvre. The numerical solution of optimal control problem is solved by a direct collocation method. Thecomputational results is used to reveal the structure of optimal solution which is composed of several arcs, each ofwhich can be identified by the corresponding manoeuvre executed and constraints active.Keywords: trajectory shaping, direct collocation, optimal control, minimum integrated altitud
PEMBUATAN PADUAN (Ti1-xAlx)N DENGAN TEKNIK PLASMA CVD DARI BUBUK AlCl3, GAS N2 DAN H2, SERTA LARUTAN TiCl4
Get PDF The substitution of Ti atoms by Al atoms in TiN lattice sites to form (Ti1-xAlx)N is clearly demonstrated by the coatings which were deposited on steel substrate and using plasma CVD technique. The presence of Al atoms in TiN lattice site is shown by means of XRD and EDX techniques: lattice parameters decreasing of TiN as the fraction of Al increases (XRD) and precipitation of hexagonal AlN phase (XRD) as the fraction of Al exceeding 0.8 (EDX). The hardness of these coating are just around 30 GPa, which is beyond the values reported in literatures.Keywords: (Ti1-xAlx)N, plasma CV
STUDI PENGARUH PROSES PENCUCIAN GARAM TERHADAP KOMPOSISI DAN STABILITAS YODIUM GARAM KONSUMSI
Get PDFEffect of Salt Washing Process on Content and Iodium Stability of Salt. Salt washing process should increase the saltquality. It should clean the salt from sludge or clay and also reduce the impurity compound such as Mg, Ca and the reductorcontent. The objective of these reseach is to assess the effect of washing process on the content og hygroscopic impuritiescompound (Ca and Mg), and reductor content of salt. The research also investigate the water absorbing, pH, KIO3 contentas function of time to obtain effect of washing process on KIO3 stability in salt. The experiment result shows that the lowestcontent of Mg and reductor compound 0.016 % wt and 2.65 ppm respectively which is reached at the fi ne salt washingprocess using 27 % wt brine. The analysis of water content indicates an increase the Ca and Mg content, causing an waterabsorbtion in salt , However the effect on pH the is not clear.Keywords: Washing salt food, salt quality, iodium stabilit
PEMODELAN DAN SIMULASI KATALITIK KONVERTER PACKED BED UNTUK MENGOKSIDASI JELAGA PADA GAS BUANG KENDARAAN BERMESIN DIESEL
Get PDFModelling 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 engin
SIMPLE: SISTIM PENILAI ESEI OTOMATIS UNTUK MENILAI UJIAN DALAM BAHASA INDONESIA
Get PDFSIMPLE: System Automatic Essay Assessment for Indonesian Language Subject Examination. Evaluation ofstudy of a student is a very important aspect of an educational process. Evaluation is aimed at measuring the level ofstudent understanding of the given lecture materials. Measuring student understanding of the course material, usingessay-type exam, is generally used as the evaluation tool. In this essay-type exam, the student has to answer questionsusing sentences, whereby choices of possible answers are not indicated. The student has to answer the questions withhis/her sentences. The answers may vary, since it reflects the student's best thoughts of the materials. One of theweaknesses of essay-type exam is the difficulty to grade the answers and it tends to be time consuming. Currently,automatic grading systems that may speed up the grading process, are being developed in many research institutions.The method used to grade, varies form one system to another, and one of the popular system is the Latent SemanticAnalysis (LSA). LSA is a method of grading essay by extracting words and representing the sentence in the form ofmathematical or statistical formulation, from a text with a relatively large number of words. The grade of the essay isdetermined, by matching the important words to a group of words prepared by the human rater. This paper describes aneffort to developed LSA, enhanced with word weighting, word order and the word synonym to improve the accuracy ofgrading. This system is called SIMPLE. SIMPLE is used to grade answers using bahasa Indonesia. The exam is carriedout on-line through the Web. From the experiments conducted, for small classes, the conformity of grade compared tothe grade of human rater lies between 69.80 % - 94.64 %, and for medium size classes the conformity lies between77.18 % - 98.42 % with the human rater. These results are roughly proportional with the result of LSA system, whichgrade essay given in English.Keywords: SIMPLE, latent semantic analysis, on-line examination, we
CONSTRUCTION OF SHORT-LENGTH HIGH-RATES LDPC CODES USING DIFFERENCE FAMILIES
Get PDFLow-density parity-check (LDPC) code is linear-block error-correcting code defined by sparse parity-check matrix. It isdecoded using the massage-passing algorithm, and in many cases, capable of outperforming turbo code. This paperpresents a class of low-density parity-check (LDPC) codes showing good performance with low encoding complexity.The code is constructed using difference families from combinatorial design. The resulting code, which is designed tohave short code length and high code rate, can be encoded with low complexity due to its quasi-cyclic structure, andperforms well when it is iteratively decoded with the sum-product algorithm. These properties of LDPC code are quitesuitable for applications in future wireless local area network.Keywords: low-density parity-check codes, quasi-cyclic codes, difference families, combinatorial design, iterativedecoding, wireless local area networ
KINETIC MODEL FOR TRIGLYCERIDE HYDROLYSIS USING LIPASE: REVIEW
Get PDFTriglyceride hydrolysis using lipase has been proposed as a novel method to produce raw materials in food andcosmetic industries such as diacylglycerol, monoacylglycerol, glycerol and fatty acid. In order to design a reactor forutilizing this reaction on industrial scale, constructing a kinetic model is important. Since the substrates are oil andwater, the hydrolysis takes place at oil-water interface. Furthermore, the triglyceride has three ester bonds, so that thehydrolysis stepwise proceeds. Thus, the reaction mechanism is very complicated. The difference between theinterfacial and bulk concentrations of the enzyme, substrates and products, and the interfacial enzymatic reactionmechanism should be considered in the model.Keywords: Lipase, kinetic model, enzymatic reaction mechanism, hydrolysis, triglycerid