Judul: The Influence of Ultrasonication and Stirring in Synthesis of Nanohydroxyapatite Based Chicken Eggshell
Abstrak: Hidroksiapatit pada tulang alami manusia berbentuk jarum yang mempunyai struktur nano, sehingga diperlukan hidroksiapatit yang sesuai dengan ukuran pada struktur tulang tersebut. Penelitian ini menggunakan tiga metode untuk menghasilkan nanohidroksiapatit yaitu sintesis hidroksiapatit dengan ultrasonikasi kalsium oksida terlebih dahulu, ultrasonikasi dilakukan pada saat presipitasi dan ultrasonikasi dilakukan setelah serbuk hidroksiapatit diperoleh. Hasil uji x-ray diffractometer dan particle size analyzer menunjukkan bahwa metode kedua merupakan metode yang optimum untuk menghasilkan nanohidroksiapatit. Metode ini menghasilkan fasa hidroksiapatit dan beberapa fasa lain seperti octacalcium phosphate dan tricalcium phosphate serta menghasilkan distribusi ukuran partikel paling kecil yaitu ±15 nm. Hasil uji x-ray diffractometer dan particle size analyzer pada metode pertama menunjukkan bahwa selain mayoritas fasa yang terbentuk adalah hidroksiapatit juga terdapat fasa lain berupa octacalcium phosphate dan tricalcium phosphate serta mempunyai distribusi ukuran partikel ±130 nm. Hasil uji x-ray diffractometer dan particle size analyzer pada metode ketiga menunjukkan mayoritas fasa yang terbentuk adalah hidroksiapatit disamping terdapat beberapa fasa lain berupa octacalcium phosphate dan tricalcium phosphate serta menghasilkan distribusi ukuran partikel ±150 nm.
Keyword: Bogor Agricultural University, Institut Pertanian Bogor, IPB, hydroxyapatite, PSA, ultrasonication, XRD, hidrosiapatit, pengadukan, bone groft

Judul: Pemanfaatan cangkang kerang darah dalam Sintesis Nanohidroksiapatit
Abstrak: Research on the synthesis and characterization of nanohydroxyapatite, by using the source of calcium from the shells of mussles blood has been conducted. This research used ultrasonic waves through ultrasonication and precipitation methods for the shyntesis. Nanohydroxyapatite obtained was based on two treatmens which were CaO powder ultrasonication and hydroxyapatite powder ultrasonication. Ultrasonication process aims to minimize the spread and average particel size by using cavitation effect of ultrasonic waves propagating in a liquid medium. Ultrasonication in this research was counducted in three variation of time which were 30, 60 and 120 minutes with three replications for each treatment. The results of XRD characterization showed that for HA from CaO ultrasonication, appeared other phases whice are TCP and OCP. The result of optimum time for ultrasonication was 60 minutes. This is because at the time of ultrasonication 30 and 120 minutes, the distribution and average particle size were very large.
Keyword: XRD, ultrasonication, PSA, Hydroxyapatite

Judul: Construction of Strongly Optimal Binary Linear Code with Minimum Distance 9 and 11
Abstrak: A binary linear code of length n over q F is a subspace of n q F . A code has three parameters that attached to it, namely length, dimension, and minimum distance. A code with length n, dimension k and minimum distance d is often called [n, k, d ]-code. Usually, when two parameters are given, then we want to find a code that has the best value for the last parameter. Based on Gilbert- Varshamov bound, if a [n, k, d ]-code exists and can not be expanded, we call it a strongly optimal code. In this paper, we construct strongly optimal code with minimum distance 9 and 11. In constructing the code, we created a theorem and algorithm based on Gilbert-Varshamov bound before we implement the algorithm to MAPLE programming language. Because of computational limitations, the program can only construct up to k = 10 for d = 9 and k = 12 for d = 11.
Keyword: