Judul: Crystallographic and Nanostructural Studies of Sr/Se Co-substituted Hydroxyapatite for Applications in Bone Graft and Anticancer Therapy
Abstrak: Sintesis berbagai biokeramik untuk aplikasi biomedis telah banyak dilakukan karena tingginya kasus cacat tulang. Salah satu sintesis yang sering dilakukan adalah sintesis hidroksiapatit (HA). Penelitian ini bertujuan menyintesis HA dengan memodifikasinya untuk mendapatkan sifat dan fungsi lain yang tidak terdapat dalam HA, seperti antikanker, dengan menambahkan ion Sr2+ dan SeO32- menggunakan metode presipitasi kimia basah. Hasil XRD menunjukkan bahwa puncak karakteristik konsisten dengan HA tanpa fase pengotor. Penambahan ion Sr2+ dan SeO32- menyebabkan penurunan ukuran kristal, kecuali pada sampel yang dikalsinasi pada suhu 1000 ?. Hasil FTIR menunjukkan keberadaan gugus OH- dan PO43- yang mengindikasikan komponen HA. Analisa EDS juga mengonfirmasi keberadaan unsur Sr dan Se dalam HA. Pengamatan TEM pada sampel yang dikalsinasi pada 1000 ? menunjukkan bentuk spherical dan peningkatan ukuran partikel seiring bertambahnya ion substitusi akibat peningkatan pertumbuhan kristal pada suhu tinggi. Analisa struktur kristal melalui TEM juga dilakukan untuk mengonfirmasi hasil XRD. Kata kunci: hidroksiapatit, kristal, partikel
Keyword: hidroksiapatit

Judul: Kajian Komposisi Hidroksiapatit yang Disintesis dengan Metode Hidrotermal
Abstrak: Accidents are the biggest factors causing injuries all over the world, and generally resulted is the form of stress fracture. The increase in the study on the handling procedures of this issue, the healing processes of bone injury are getting better one of the procedures used by many people’s by using biomaterials. Bone biomaterials commonly used are bioceramics. One of the types of bioceramics is hydroxyapatite. In this research, the synthesis of hydroxyapatite is reported. Synthesis of hydroxyapatite was done by hydrothermal method at a temperature of 150, 200, 250, and 300 oC for 3 hours and sintered at a temperature of 900 oC. At 200 oC synthesized hydroxyapatite was given a further treatment. At a temperature of 200 oC synthesizing procedure was back to the time variation, i.e. 1 hour and 5 hours. The results of the characterization of Fourier Transform Infrared Spectroscopy (FTIR) for all the samples showed hydroxyapatite phase at a temperature of 200 oC. The results of the characterization of Atomic Absorption Spectroscopy (AAS) for all samples showed hydroxyapatite formed is not pure because there are also some other phases.
Keyword: Hydrothermal, Hydroxyapatite, Fourier Transform Infrared Spectroscopy, Atomic Absorption Spectroscopy

Judul: Model Input-output dalam Masalah Network Flow
Abstrak: Production process is a process, which is done by industry, to transform input into output. According to the type of output and its activity, industry can be classified into various sectors, which are connected to each other. Therefore, a model to analyze the connection among sections is needed. The model is known as input-output model (IO model). IO model presents an IO table, which shows informations about the transaction between goods and services in each economic sector. Furthermore, the IO model also shows that the amount of all input is the same as the amount of all output. In this paper, the transaction of each economic sector in IO table is analyzed using network flow theory. The formulated network flow problem implies that each sector represents partly as a producer and also as a consumer. This paper also solves a minimum cost circulation problem.
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