The objectives of this research were to ?nd (1) the optimum boron dose for treating rhab- domyosarcoma in the head and neck regions and (2) the effective irradiation time to treat rhab- domyosarcoma in the head and neck regions. This research used the particle and heavy ions transport code system (PHITS) to simulate the neutron source and BNCT doses. The neutron source used was Kartini Reactor. The simulation was carried out by creating the geometry of cancer tissue in the head and neck regions. Boron concentration variance was 30, 35, 40, 45, and 50 µg/g tissue. The output of PHITS was a neutron ?ux and neutron dose. The neutron ?ux value was used to acquire the alpha dose, proton dose, and gamma dose inside the tissue. The results showed that (1) the optimum boron dose for treating rhabdomyosarcoma in the head and neck regions was 50 µg/g tissue and (2) the effective irradiation time was 7 hours and 4 minutes, which was acquired with a boron concentration of 50 µg/g tissue. The higher the boron concentration level, the higher the dose rate, the quicker the irradiation time, and the lower the radiation dose received by healthy tissues.

Relocation and freezing of molten core materials mixed with solid phases are among the important thermal-hydraulic phenomena in core disruptive accidents of a liquid-metal-cooled reactor (LMR). To simulate such behavior of molten metal mixed with solid particles flowing onto cold structures, a computational framework was investigated using two moving particle methods, namely, the finite volume particle (FVP) method and the distinct element method (DEM). In FVP, the fluid movement and phase changes are modeled through neighboring fluid particle interactions. For mixed-flow calculations, FVP was coupled with DEM to represent interactions between solid particles and between solid particles and the wall. A 3D computer code developed for solid-liquid mixture flows was validated by a series of pureand mixed-melt freezing experiments using a low-melting-point alloy. A comparison between the results of experiments and simulations demonstrates that the present computational framework based on FVP and DEM is applicable to numerical simulations of solid-liquid mixture flows with freezing process under solid particle influences.KEYWORDS: moving particle methods, finite volume particle (FVP) method, distinct element method (DEM), multiphase flow with phase change

Relocation and freezing of molten core materials mixed with solid phases are among the important thermal-hydraulic phenomena in core disruptive accidents of a liquid-metal-cooled reactor (LMR). To simulate such behavior of molten metal mixed with solid particles flowing onto cold structures, a computational framework was investigated using two moving particle methods, namely, the finite volume particle (FVP) method and the distinct element method (DEM). In FVP, the fluid movement and phase changes are modeled through neighboring fluid particle interactions. For mixed-flow calculations, FVP was coupled with DEM to represent interactions between solid particles and between solid particles and the wall. A 3D computer code developed for solid-liquid mixture flows was validated by a series of pureand mixed-melt freezing experiments using a low-melting-point alloy. A comparison between the results of experiments and simulations demonstrates that the present computational framework based on FVP and DEM is applicable to numerical simulations of solid-liquid mixture flows with freezing process under solid particle influences.KEYWORDS: moving particle methods, finite volume particle (FVP) method, distinct element method (DEM), multiphase flow with phase change

Measurement instruments of physics, especially those dedicated as teaching aids in physics classroom are improving. These measuring instruments are not only used for measurement purposes, but also to apply theoretical concept into the real world, thus making it easier for students to comprehend. Therefore, this study aims to design, construct, and test a distance-measuring instrument based on the law of light reflection, especially for teaching physics. The method used in this study is quantitative-descriptive method, with the stages of designing, constructing, developing, and testing the distance-measuring instrument. The measuring instrument is constructed from simple, inexpensive, and easily obtained tools and materials, and it is an improvement version of a similar instrument previously developed. The testing stage of this instrument shows that the distance measurement results using the instrument is in good agreement with the results using a ruler depending upon the fixed flat mirror angle of the instrument.

Konsep dinamika fluida sering diaplikasikan dalam penyelesaian masalah di kehidupan sehari-hari, salah satunya gerakan sloshing pada kontainer yang berisi cairan. Penelitian ini bertujuan untuk menyusun sebuah code simulasi sloshing pada kontainer segi empat dengan menggunakan persamaan Navier-Stokes dua dimensi. Persamaan Navier-Stokes digridesaikan dengan ACM (Artificial Compressibility Method) dan  metode beda hingga berbasis staggered grid. ACM digunakan untuk memperoleh nilai dari komponen kecepatan dan tekanan sedangkan metode beda hingga digunakan dalam proses diskritisasi untuk melakukan pendekatan secara numerik. Karena dalam kasus ini melibatkan aliran multifase, maka metode lain seperti VOF (Volume of Fluid) juga digunakan untuk menentukan permukaan bebas fluida. Hasil penelitian ini divalidasi dengan simulasi pembanding menggunakan Ansys, dan menunjukkan kesesuaian yang cukup baik secara kuantitatif maupun kualitatif. Secara kuantitatif, nilai RMSE (Root Mean Square Error) relatif sangat kecil dengan RMSE maksimum adalah 0,235 dan RMSE minimum adalah 0,030. Sedangkan secara kualitatif, fase gerak antara kedua simulasi menunjukkan kesamaan. Dengan mengubah beberapa parameter simulasi, diketahui bahwa RMSE paling minimum diperoleh saat nilai dx=0,08 dan dy=0,0143.