Judul: Simulasi Sebaran Panas Tungku Sekam Berbentuk Kerucut Dalam Sistem Koordinat Konikal
Abstrak: Tungku sekam merupakan rangka bakar dengan berbahan bakar sekam padi. Secara umum, tungku sekam memiliki dua komponen geometri utama yaitu geometri silinder dan geometri kerucut. Geometri silinder digunakan sebagai sumber panas sedangkan kerucut sebagai tandon panas yang menyampaikan panas ke bagian lainnya. Transfer panas dan sebaran panas merupakan kejadian penting yang berhubungan dengan besar temperatur, kecepatan fluida, serta besar energi yang dihasilkan. Semakin besar temperatur, kecepatan fluida, dan energi yang angka dihasilkan suatu tungku maka sebaran panas pada tungku tersebut semakin baik. Sebaran panas tungku juga dipengaruhi oleh bentuk desain tungku. Profil sebaran panas tungku dapat diketahui dengan bantuan komputasi. Salah satu metode komputasi yang digunakan untuk mengetahui profil sebaran panas tungku adalah FDM (Finite Difference Method). FDM merupakan salah satu teknik numerik untuk menyelesaikan persamaan diferensial. Berdasarkan metode yang digunakan, telah dilakukan simulasi sebaran panas tungku sekam berbentuk kerucut dalam sistem koordinat konikal. Simulasi ini bertujuan mempelajari mekanisme transfer panas konduksi dan konveksi yang terjadi pada kerucut tungku. Simulasi dilakukan dengan cara menganalisis fenomena konduksi dan konveksi yang terjadi pada kerucut tungku sekam dengan temperatur awal diseluruh kerucut adalah temperatur ruang, temperatur bawah kerucut sebesar 700oC, dengan selang waktu 45 dan 60 detik. Melalui persamaan hantaran kalor yang dihitung secara numerik dengan metode FDM dihasilkan kecepatan aliran fluida konveksi selama 45 detik dan 60 detik adalah 13.69 m/s dan 11.90 m/s.
Keyword: Konduksi, konveksi, sebaran panas, FDM, sistem konikal koordinat

Judul: Simulasi Sebaran Panas pada Silinder Tungku Sekam dengan Berbantuan FDM(Finite Difference Method)
Abstrak: Simulation of heat distribution on cylinder furnace husks with FDM (Finite Difference Method) has been performed. These simulations is aimed to study the relationship between the velocity of fluid and the temperature at cylindrical furnace chaff. The simulations was done by analyzing the phenomena of the conduction and convection that occur in cylinder furnace husks with initial temperatures throughout cylindrical set at room temperature, and temperature under the cylinder is 491 oC for one minute. By calculating the numeric equation of heat transfer with FDM, fluid flow velocity convection with constant temperature in blanket cylinder during 1 minute is ranged between 3.32 to 13.75 m/s. In the same time, fluid flow velocity of convection with not constant temperature in blanket cylinder is ranged between 2.00 – 13.75 m/s.
Keyword: silinder tungku sekam, FDM, konveksi, konduksi, Sebaran panas

Judul: Inhibitory Control of Former Drug Users.
Abstrak: Inhibitory control is one of the characteristic functions of the prefrontal cortex by which inappropriate responses to extrinsic stimuli are avoided. On the other hand, poor inhibitory control and perseveration are the common symptoms among drug users. A little known study related to the inhibitory control, including the perseveration among former drug users in Indonesia. The Go/ NoGo task was used during the research. Seventeen former drug users and seventeen controls with no record in drug abuse were asked to do the Go/ NoGo task. Former drug users show the same ability to recognize the meaning of the cue, i.e Go cue and NoGo cue, as well as in controls. However, we found the difficulty to stop Go response in NoGo trials in former drug users, which means the failure of inhibitory response. The perseveration to the old meaning of cue was also found during the reversal phase of the task. Our study suggests that less inhibitory control and perseveration behavior occurred in former drug users. These findings suggest that even the former drug users already finished or in progress of rehabilitation program, they may still have the tendency to initiate the drug abuse. Keyword: former drug users, Go/ NoGo task, inhibitory control, perseveration
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