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Abstrak :
The Fukushima accident resulted in the melting of the reactor core due to loss of supply of coolant when the reactor stopped from operating conditions. The earthquake and tsunami caused loss of electricity due to the flooding that occurred in the reactor. The absence of the coolant supply after reactor shutdown resulted in heat accumulation, causing the temperature of the fuel to rise beyond its melting point. In the early stages of the accident, operator could not determine the severity of the accident and the percentage of the reactor core damaged. The available data was based on the radiation exposure in the environment that was reported by the authorities. The aim of this paper is to determine the severity of the conditions in the reactor core based on the radiation doses measured in the environment. The method is performed by backward counting based on the measuring radiation exposure and radionuclides releases source term. The calculation was performed by using the PC-COSYMA code. The results showed that the core damage fraction at Dai-ichi Unit 1 was 70%, and the resulting individual effective dose in the exclusion area is 401 mSv, while the core damage fraction at Unit 2 was 30%, and the resulting individual effective dose was 99.1 mSv, while for Unit 3, the core damage fraction was 25% for an individual effective dose of 92.2 mSv. The differences between the results of the calculation for estimation of core damage proposed in this paper with the previously reported results is probably caused by the applied model for assessment, differences in postulations and assumptions, and the incompleteness of the input data. This difference could be reduced by performing calculations and simulations for more varied assumptions and postulations.

Abstrak :
Minyak nabati terozonasi (Oleozon) telah terbukti memiliki kemampuan anti bakteri. Oleozon belum diproduksi untuk umum karena penelitian selama ini hanya berfokus pada produk dan belum meninjau sisi efektivitas pada reaktor untuk mensintesis oleozon. Pada penelitian ini digunakan minyak kedelai sebagai bahan baku dan diozonasi dengan menggunakan reaktor berpengaduk turbin yang terbuat dari stainless steel sehingga dapat digunakan pada tekanan diatas 1 atm dan reaktor kaca yang digunakan untuk ozonolisis pada tekanan atmosferik. Ozonator yang digunakan memiliki produktivitas ozon sebesar 0.589 g/jam untuk atmosferik dan 0,754 mg/jam. Kondisi operasi yang paling efektif untuk membuat oleozon adalah pada tekanan diatas atmosferik (1,2 bar) yang memiliki nilai bilangan asam sebesar 3,005 𝒎𝒈 𝑲𝑶𝑯 𝒎𝒈 𝒔𝒂𝒎𝒑𝒆𝒍 dan bilangan peroksida 12,353 𝒎𝒆𝒒 𝒌𝒈 𝒍𝒆𝒎𝒂𝒌. Pada variasi suhu, suhu rendah (15 ° C -19 °C) memiliki kualitas minyak terbaik dengan bilangan asam sebesar 0,84 𝒎𝒈 𝑲𝑶𝑯 𝒎𝒈 𝒔𝒂𝒎𝒑𝒆𝒍 dan bilangan peroksida 0,748 𝒎𝒆𝒒 𝒌𝒈 𝒍𝒆𝒎𝒂𝒌 serta dengan kecapatan pengaduk 150 RPM.

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Ozonated vegetable oil (Oleozon) has proven having a function as anti bacteria. Oleozon has not produced to the public because the research about oleozon still focused on the products only and never research about the effectiveness of reactor for oleozon synthesize. On this research, soybean oil is used as raw material and been ozonized in two stirred reactor which using turbine impeller that can be used on pressure above 1 atm and the glass reactor that used for atmospheric pressure. Ozone productiom from ozonator are 0,589 mg/h for atmospheric condition and 0,754mg/r for pressurized condition. The most effective operating conditions to produce oleozon is on pressure above atmospheric (1,2 bar) that has acid value about 3,005 𝒎𝒈 𝑲𝑶𝑯 𝒎𝒈 𝒔𝒂𝒎𝒑𝒍𝒆 and peroxide value about 12,353 𝒎𝒆𝒒 𝒌𝒈 𝒇𝒂𝒕 ; low temperature (15 °C-19 °C) that has acid value about 0,84 𝒎𝒈 𝑲𝑶𝑯 𝒎𝒈 𝒔𝒂𝒎𝒑𝒍𝒆 and peroxide value about 0,748 𝒎𝒆𝒒 𝒌𝒈 𝒇𝒂𝒕 ; and speed of impeller is 150 RPM.

Abstrak :
[Dalam penelitian ini dilakukan sintesis minyak terozonasi dari minyak bunga matahari dengan reaksi ozonolisis secara semi-kontinu selama 12 – 72 jam. Ozonolisis dilakukan pada tiga variasi tekanan operasi (atmosferik, bertekanan, dan vakum) menggunakan reaktor semi-batch khusus berbahan stainless steel berpengaduk turbin dan berjaket pendingin. Ozonator yang digunakan adalah rancangan sendiri dengan laju alir udara masukan sebesar 540 L/jam dan konsentrasi ozon keluaran sebesar 520 mg/jam. Kondisi reaksi dijaga pada suhu 15 – 22 °C. Pengujian kualitas hasil ozonasi dilakukan dengan metode bilangan asam, bilangan peroksida, bilangan iod, analisis viskositas, dan analisis FT-IR. Berdasarkan hasil penelitian, kecepatan pengadukan terbaik adalah 150 RPM dengan pola aliran transisi dan tekanan operasi terbaik untuk sintesis minyak terozonasi dari minyak bunga matahari adalah tekanan atmosferik (1 atm)., In this study, synthesis of ozonated vegetable oil was made ftom sunflower oil with semi-continue ozonolysis for 12 – 72 hours. Ozonolysis was done in three variation of operation pressure (atmospheric, pressurized, and vacuum) by using particular strirred semi-batch reactor from stainless steel with cooling jacket. Ozonator used was self-designed with input air flowrate of 540 L/h and ozone concentration output of 520 mg/h. The reaction condition maintained at temperature of 15 – 22 oC. Minyak terozonasi product testing was done with several methods such as analysis of acidic value, peroxide value, iodin value, viscosity, and FT-IR. Based on this research, the best stirrer speed is 150 RPM and the best pressure condition for minyak terozonasi synthesis from sunflower oil is atmospheric pressure (1 atm).]

Abstrak :
Gamma Valerolactone (GVL) merupakan senyawa organik turunan dari asam levulinat yang memiliki banyak kegunaan, salah satunya adalah sebagai aditif bahan bakar. Penelitian ini difokuskan pada perancangan reaktor unggkun trickle skala komersial untuk sintesis GVL dari asam levulinat pada katalis Ru/C. Pemodelan matematis yang digunakan adalah model reaktor unggun trickle aksisimetri dua dimensi untuk perpindahan massa dan momentum di celah unggun, aksisimetri dua dimensi untuk perpindahan energi di dalam unggun, dan satu dimensi untuk perpindahan massa dan di partikel katalis. Tujuan dari penelitian ini adalah mendapatkan desain reaktor dengan volume paling kecil untuk produksi GVL sebanyak 1.239 ton. Desain reaktor dilakukan melalui simulasi pada COMSOL Multiphysics 5.5, dengan mengubah parameter operasi berupa suhu, tekanan, GHSV, LHSV, dan diameter katalis, sehingga didapatkan kondisi optimal pada masing-masing parameter. Hasilnya, didapatkan parameter operasi optimal dengan suhu 423 K, tekanan 25 bar, GHSV 0.065 s-1, LHSV 0.00117 s-1, diameter katalis 3 mm, diameter reaktor 5 cm, dan panjang reaktor 5 m. Laju alir yang dihasilkan dari reaktor skala komersial dengan kondisi optimal adalah 7.06 kg/hari, sehingga diperlukan 536 buah tube untuk memperoleh kapasitas produksi sebanyak 1.239 ton. ...... Gamma Valerolactone (GVL) is an organic compound derived from levulinic acid that has many uses, one of which is as a fuel additive. This research is focused on designing a commercial scale trickle bed reactor for the synthesis of GVL from levulinic acid on a Ru/C catalyst. The mathematical modelling used is a two-dimensional axisymmetric trickle bed reactor model for mass and momentum transfer in the bed gap, two-dimensional axisymmetric for energy transfer in the bed, and one-dimensional for mass transfer and in the catalyst particles. The objective of this research is to obtain a reactor design with the smallest volume to produce 1,239 tons of GVL. The reactor design was carried out through simulations on COMSOL Multiphysics 5.5, by changing the operating parameters such as temperature, pressure, GHSV, LHSV, and catalyst diameter, so that optimal conditions were obtained for each parameter. As a result, the optimal operating parameters were obtained with temperature 423 K, pressure 25 bar, GHSV 0.065 s-1, LHSV 0.00117 s-1, catalyst diameter 3 mm, reactor diameter 5 cm, and reactor length 5 m. The flow rate produced from a commercial scale reactor with optimal conditions is 7,06 kg/day, so 536 tubes are needed to obtain a production capacity of 1,239 tons.