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GEMA TEKNOLOGI
Published by Universitas Diponegoro
ISSN : 08520232     EISSN : 2656582X     DOI : -
Core Subject : Science,
Gema Teknologi Journal (pISSN : 0852-0232, eISSN : 2656-582X) is an open access journal published by Vocational School, Diponegoro University, Indonesia. Gema Teknologi publishes articles from various engineering disciplines (the results of original scientific research or new scientific studies of literature). Editor receives articles both in English and Indonesian. Gema Teknologi Journal is published 2 (two) times a year, on April and October.
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Articles 7 Documents
Search results for , issue " Vol 16, No 4 (2012): Periode Oktober 2011 - April 2012" : 7 Documents clear
SIMULASI SISTEM EKSITASI UNTUK KONDENSATOR SINKRON PADA PEMBANGKIT LISTRIK TENAGA ANGIN Sukmadi, Tejo
GEMA TEKNOLOGI Vol 16, No 4 (2012): Periode Oktober 2011 - April 2012
Publisher : GEMA TEKNOLOGI

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Abstract

Tejo Sukmadi, in paper a model of  wind energy power generation excitation system will be simulated. The  focuse was on the modelling and parameters optimization of the DC1A type excitation systems for synchronous condenser as voltage regulation on the power plant. Excitation system optimization is made by using genetic algorithms method. The parameters optimization should have the optimal combination and the voltage regulation of wind energy power plants model find the best vale when there is a change in the wind speed. The simulation and analysis found that systems with excitation system parameterized combination of genetic algorithms experiment using crossovers opportunities 0.6 and mutations opportunities 0.032, which Ka = 297.2350, Ke = 0.6162, Kf = 0.01, Ta = 0.01, Te = 0.01 and Tf = 0.6278 is the best combination of excitation parameters obtained. By generating the 115.6604 ITAE value, over shoot 1,54%, steady state 0,44 s, the smallest voltage value after wind speed change is 0.9957 pu and the largest voltage value after wind speed change is 1.0025 pu. Keywords : wind energy power generation, excitation system, synchronous condenser, genetic algorithms.
ANALISA KERETAKAN PADA KONSTRUKSI GELADAK UTAMA KM. ADRI XLIV Djazuli Sa’id, Solichin
GEMA TEKNOLOGI Vol 16, No 4 (2012): Periode Oktober 2011 - April 2012
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Abstract

Solichin Djazuli Sa’id, in this paper explain that ship KM. XLIV Adri is the kind of cargo ship (General Cargo). The ship has been designed in accordance with the rules and regulations of the class (Bureau of Classification Indonesia). From the results of the survey method of research vessel, discovered the damage to construction on the main deck, the cracks on the fulcrum side deck fit the front room and deck beams are broken the back of the main deck. Thus causing the curvature of the floor deck and it needs to be a replacement / repair of components damaged by construction ensuring shipping safety. From the calculation results and field studies, construction damage caused by welding is not good, cutting the material that is not true and the use of payload on the main deck in excess of the permitted capacity. Key words: Cargo Ship , Construction Damages, Main Deck
ANALISA KARAKTERISTIK BIODIESEL NYAMPLUNG Darmanto, Seno; Sediono, Windu; Sarwoko, Sarwoko; Triyatno, Triyatno
GEMA TEKNOLOGI Vol 16, No 4 (2012): Periode Oktober 2011 - April 2012
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Abstract

Seno Darmanto, Windu Sediono, Sarwoko, Triyatno, in this paper explain that making of callophylum inophylum biodiesel fuel is done alkaly transesterification methode. Alkaly transesterification methode use methanol and basa (NaOH) of catalist. Procedur and setting of research that is consisted in material selection, treatment and setting of composition of methanol and catalist, operational temperature, reaction time, speed and mixer technical will effect quality and conversion level of callophylum inophylum biodiesel. And based data analyzer show that conversion of callophylum inophylum biodiesel can reach 90%. Properties of callophylum inophylum biodiesel show viscosity and flash point of callophylum inophylum biodiesel is ligthly higher than diesel fuel. And caloric value of callophylum inophylum biodiesel is slightly lower than diesel fuel. Key words: callophylum inophylum, biodiesel, properties, transesterification.
EKSTRAKSI ASAM LEMAK BEBAS DARI MINYAK NABATI DENGAN METANOL KAJIAN PERPINDAHAN MASSA Wahyuningsih, Wahyuningsih; Endy Yulianto, Moh
GEMA TEKNOLOGI Vol 16, No 4 (2012): Periode Oktober 2011 - April 2012
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Abstract

Wahyuningsih, Moh Endy Yulianto, in this paper explain that extraction of free fatty acids from vegetable oils with methanol performed in batch stirred tank, in a variety of conditions. Variables experiments in liquid-liquid extraction including temperature, solvent ratio and rotational speed stirrer. This study aims to develop a correlation coefficient of mass transfer in extraction of free fatty acids from vegetable oils methanol. Rresearch was conducted in two phases. Was the first stage liquid-liquid extraction experiments in laboratory. Second step is the development of an empirical correlation for the mass transfer coefficients in the form of numbers not berdemensi results showed that the greater the temperature, turn the mixer speed and solvent-feed ratio of the mass transfer koffisien gained greater. Mass transfer coefficient expressed in Sherwood number and correlated against the Reynolds number, Schmitd, (dP / dT) and (L / S), the results obtained: Sh = 4,669 x 10-5 Re 0,462 Sc0,5 (dP/dT)0,308 (L/S)0,187 If used to calculate the mass transfer coefficients, have an average error of 8.79% for the regression line. This equation was developed in the Re number range 3169 to 11 750; numbers Sc 6321 to 9896, (dp / dT) from 0.0007 to 0.0013 and (L / S) of 0.333 to 1. Keywords: nabati oil extraction
APLIKASI TAPIS PELEWAT RENDAH LC (LOW PASS LC FILTER) UNTUK MEREDUKSI DISTORSI HARMONISA PADA LAMPU HEMAT ENERGI Sasmoko, Priyo; Subali, Subali; Yuwono, Teguh
GEMA TEKNOLOGI Vol 16, No 4 (2012): Periode Oktober 2011 - April 2012
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Abstract

Priyo Sasmoko, Subali, Teguh Yuwono, in this paper explain that harmonic (current or voltage) is one of the problems that has to be solved in electric power system, especially that caused by non-linear loads. Harmonic could cause bad impacts for the electric components that sensed it. It is almost certain that using of fluorescent lamp with electronic ballast or it is called energy saving lamp can cause harmonic in electric power system. Considering of the using of energy saving lamp is increased fairly fast as residence and office lighting, so it is important to analyze and solve the harmonic that caused by energy saving lamp. From the harmonic analysis, we can know the harmonic distortion caused by energy saving lamp. And there are some efforts to reduce such harmonic distortion by using a Low Pass Filter. Keyword: power quality, harmonic, low pass filter.
PENGARUH TEMPERATUR TERHADAP PEMBENTUKAN KERAK GIPSUM DALAM PIPA Sutrisno, Sutrisno; S. Muryanto, S. Muryanto; Bayuseno, AP
GEMA TEKNOLOGI Vol 16, No 4 (2012): Periode Oktober 2011 - April 2012
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Abstract

Sutrisno, S. Muryanto, AP Bayuseno, in this paper explain that gypsum crust (CaSO4.2H2O) that occurs in the pipe very detrimental to the industry because it resulted in narrowing of the cross-section, reinforcing walls, inhibit heat transfer and slow processing time. Therefore, gypsum crust should be prevented or inhibited growth. Gypsum crust growth is affected by the concentration, temperature and flow rate as well as impurities. This study aimed to determine the effect of temperature on the formation of gypsum crust. Gypsum scaling experiments carried out by reacting a NaSO4 with CaCl2 in a test tool that has been designed. The experiments were performed at a temperature of 27oC-50oC with Ca2 + concentration of 3500 ppm, flow rate 30 ml / min and stainless steel test pipes. Results from this study showed a rise in temperature by lowering the induction time and increase mass scale and make a longer crystal sizes. Test results morphology, composition and purity of the results of the experiment showed that the crust was beanr gypsum. Keywords : gypsum, scale, temperature
MENGGAGAS SUATU KAWASAN INDUSTRI Sutanto, Sutanto
GEMA TEKNOLOGI Vol 16, No 4 (2012): Periode Oktober 2011 - April 2012
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Abstract

Sutanto, in this paper explain that industrial area is the area where the concentration of industrial activities whose existence the ideal should be integrated with other areas such as residential, office, education, economic activity and other agricultural green belt - the other. This industrial area should be equipped with infrastructure and other support facilities so as to serve the upstream to downstream processes. The necessary infrastructure and facilities such as office managers, environmental facilities, the network - a network of roads, electricity, telecommunications, sewage, water, fire and reforestation. For industrial buildings must meet the requirements of building height, building area coefficient referring to the City Master Plan. Keywords: city master plan

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