Judul: Finite-Difference Approximations to The Heat And Diffusion Equation
Abstrak: Penelitian ini mengkaji dua model persamaan difusi konveksi panas, Zero-Order model dan First-Order model yang diturunkan dari persamaan adveksi dan dikombinasikan dengan variabel sumber atau penyusutan panas (S). Nilai S pada Zero-Order model tidak bergantung suhu , sehingga memiliki karakteristik linear yang menjadikan suhu sistem berubah secara konstan untuk setiap selang waktu. Nilai S pada First-Order model bergantung terhadap suhu, sehingga suhu sistem berubah secara eksponensial untuk setiap selang waktu. Kondisi aliran yang bersifat incompressible diasumsikan pada penelitian ini. Kedua model tersebut diselesaikan dengan menggunakan dua metoda Beda Hingga. Forward Time Centered Space (FTCS) and Crank-Nicolson (CN). Kondisi aliran yang incompressible menyebabkan kecepatan konveksi dengan nilai dibawah 0.3 Mach tidak akan mempengaruhi proses transfer panas menjadi konveksi secara signifikan. Kecepatan konveksi akan mempengaruhi proses transfer panas jika memiliki nilai diatas 0.3 Mach. Hasil yang tidak stabil akan muncul dalam beberapa kondisi simulasi, khususnya pada metoda FTCS. Hal ini dikarenakan metoda FTCS merupakan metoda eksplisit yang secara tanpa syarat tidak stabil dan sangat sensitif terhadap nilai iterasi, ukuran step, dan beberapa nilai konstanta tambahan di dalam persamaan.
Keyword: Bogor Agricultural University (IPB), konveksi, difusi, Crank-Nicolson, Beda-Hingga, adveksi

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: Posisi Filogenetik Kura-Kura Carettochelys Insculpta  (Reptillia: Testudinata)
Abstrak: Carettochelys insculpta is an endemic freshwater turtle of southern Papua and northern Australia. Phylogenetic position of this turtle is remain unresolved until now. Most of the research conducted show close relationships of C. insculpta and members of Trionychidae family. However, some of the research show distance between C. insculpta and members of Trionychidae family. This research is conducted to analyze phylogenetic relationship between C. insculpta and other members of Testudinata using 12S rRNA, 16S rRNA, and both gene as markers. DNA samples were obtained from three different organisms of C. insculpta. Two species used as outgroups were Alligator mississippiensis and Iguana iguana. Phylogenetic analysis was carried out using Neighbor-Joining method with Felsenstein 1981 (F81) modeltest. A polytomy tree of Testudinata was produced by using 12S rRNA gene. However, analysis using 16S rRNA and both genes as markers confirmed that C. insculpta was located between the Chelonidae and the Trionychidae family.
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