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INDONESIA
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 5 Documents
Search results for , issue " Vol 15, No 1 (2006): Periode April - Oktober 2006" : 5 Documents clear
MOMEN SEKUNDER PADA STRUKTUR TRUSS Purba, Parhimpunan
GEMA TEKNOLOGI Vol 15, No 1 (2006): Periode April - Oktober 2006
Publisher : GEMA TEKNOLOGI

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Abstract

Parhimpunan Purba, in paper truss struktur at secondary momen explain that analyse structure of truss conducted with a scription that extension or joint behavioral hinges. This matter own feebleness since joint weared by the appliance joint bolt, rivet and welded. So that the extension become stiff.In this handing out studied by problem of joint behavioral stiff that make the secondary moment. To know how about of the secondary moment, conducted by determining secondary stresses. Secondary stresses compare by the stress that happened or primary stresses.The result of calculation shows that ratio of secondary stresses and primary stresses expressed in long (L) and high (h) of the bar. For L/h equal 1/10 ratio of secondary and primary stresses about 6,2% if one of the joint is hinges and become 8,3% if all of the joint are stiff. Matter this need to get attention in design and also research.
ANALISA WAKTU PELEPASAN KARAT TERHADAP BERAT KARAT YANG MENGELUPAS DALAM LARUTAN HF DAN ABS Rahmat, Rahmat
GEMA TEKNOLOGI Vol 15, No 1 (2006): Periode April - Oktober 2006
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Abstract

Rahmat, in paper analise the time of rust release to rust weight flacking in condensation of HF ans ABS explain that maintenance and cleaning spare part of production engine are the main preventive to increase the efficiency of system. Rust and corrosion are the main problem of all engines. It is caused by chemical, oil, water, soil, ash or oxidation. Natural cleaning will take a long time and it isn’t effective. Base on this reason, research would like to know the time to clean the high corrosion of nail or spare parts with HF and ABS liquid. The result of this research give indication that increasing of time will produce increasing of weight of corrosion. The optimum of the corrosion’s speed cleaning is after 6 up to 9 minutes. Maximum corrosion’s speed cleaning is after 18 minutes, because the HF and ABS fluid will give effective reaction to attack the porosity of corrosion. After 27 minutes the corrosion’s speed cleaning decline, because the HF and ABS fluid will attack the base metal.Key words : corrosion, rust, HF, ABS.
MODEL PERPINDAHAN MASSA SISTEM CAIR-CAIR DALAM TANGKI BERPENGADUK DENGAN PENDEKATAN TEORI LAPISAN FILM Abidin, Zainal; Wahyuningsih, Wahyuningsih; Endy Yulianto, Mohamad
GEMA TEKNOLOGI Vol 15, No 1 (2006): Periode April - Oktober 2006
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Abstract

Zainal Abidin, Wahyuningsih, Mohamad Endy Yulianto, in paper model of mass transfer system of liquid in churn tank with coat film theory approach explain that Mass transfer in the liquid-liquid phase is an important phenomena in the extraction process. Mass transfer coefficient is one of the factors that influence the rate of mass transfer. Nowadays, in the extraction process of free fatty acid from palm oil with methanol, there’s no data of mass transfer coefficient. The goal of this research was todetermine and develop correlation of mass transfer coefficient on the extraction process of palm oil’s free fatty acid with methanol, as the solvent. Therefore, the research was held in two major steps. The first step was held a liquid-liquid extraction in the laboratory, and the second step was develop an empirical correlation for mass transfer coefficient in the term of dimensionless groups. Batch extraction was conducted in an agitated vessel. The variables that is studied in the process include temperature process, solvent to feed weight ratio, and impeller speed. Based on the data that was obtained from the experiment, the correlation equation that can be used to calculate the mass transfer coefficient was expressed by Sherwood number and could be correlated turbine Reynolds number, Schmidt number, (dp/dT) and (L/S). The result by of Sh = 6,648x10-4 Re0,194 Sc0,333 (dp/dT)0,140 (L/S)0,183The averege deviation of the equation is 9,67 % if it is intended to account for mass transfer coefficient. These dimensionless groups are developed in the range of 3169 to 11750, 6321 to 9897, 0,0007 to 0,0013, and 0,333 to 1 in the Reynolds number, Schmidt number, (dp/dT), and (L/S), respectively.Key words : extraction, mass transfer
MODEL PERPINDAHAN MASSA PROSES STEAMING INAKTIVASI ENZIM POLIFENOL OKSIDASE DALAM PENGOLAHAN TEH HIJAU Endy Yulianto, Mohamad; Ariwibowo, Didik; Arifan, Fahmi; Kusumayanti, Heni; Nugraheni, F.S.; Senin, Senin
GEMA TEKNOLOGI Vol 15, No 1 (2006): Periode April - Oktober 2006
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Abstract

Mohamad EndyYulianto, Didik Ariwibowo, Fahmi Arifan, Heni Kusumayanti, F.S. Nugraheni, Senin, in paper mass transfer model in inactivation steaming process of ocsidase polifenol enzim at green tea processing explain that tea is natural herbs for freshner and maintain body’s heart drinking because it contains catechin the bioactives agent that can prevent cancer, heart failure, myocardial infarction, eases the bowel movement, prevent infection of mouth, gum and so on. Because of it’s the high catechin is needed. The get high catechin the enzymatic oxidation of polifenol must be undergone. For the reason its needed to study an inactivated process of polifenol oxsidase enzyme by steaming. However, this process will depend on mass transfer behavior and pattern of steam penetration into tea leaves. It is effident because of its properties will influence catechin contain in fresh tea leaves. Mass transfer model of inactivation for polifenol oxsidase enzyme in high catechin green tea processing by steamingKey word : mass transfer, steaming, green tea
DIESEL ELECTRIC PROPULSION SEBAGAI ALTERNATIF POWER PLANT PADA KAPAL-KAPAL KOMERSIAL Suyadi, Suyadi
GEMA TEKNOLOGI Vol 15, No 1 (2006): Periode April - Oktober 2006
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Abstract

Suyadi, in paper diesel electric propulsion as alternative power plant at commercial boats explain that the rapid technology development in the field of electronics and computer has recently increased the popularity of Diesel-Electric Propulsion use as the main activator in the ship. The electric-propulsion offers some beneficial aspects compared to Mechanical-Propulsion. Therefore, it is a task for a Marine-engineer to minimize any harm aspects from Diesel-Electric Propulsion through design and operational as well as possible. Technical and economical aspects will be discussed in this paper as the consideration material for choosing this alternative as the power plant in the ship.Key Word : Diesel electric propulsion

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