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: Sintesis dan Karakterisasi Nanohidroksiapatit dari Cangkang Telur Ayam dengan Metode Ultrasonikasi
Abstrak: In this research synthesis and characterization of nanohidoxyapatite from chicken eggshell has been done using ultrasonication method and precipitation. To obtain nanohydroxyapatite, two treatments were applied which areCaO powder ultrasonication and HA powder ultrasonication. The aim of ultrasonication is toreduce particle size. This research was carried out by using two variation of ultrasonication time which are 1.5 and 2 hours each with three repetitions. The results of XRD characterization show that HA still contains impurities like OCP and TCP. The optimum ultrasonication time is 1.5 hours due to its smaller particle size and few impurities obtained.
Keyword: precipitation method, PSA, XRD, ultrasonication method, 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: