Judul: Synthesis of Apatite - Chitosan Composite Using Duck Eggshell and Chitosan with Temperature and pH Control
Abstrak: Composite of apatite-chitosan was prepared by using chitosan as polymer matrix. Calcium phosphate was prepared from CaO and (NH4)2HPO4, which the ratio Ca : P had to be 1.67. Chitosan is produced by deacetilase from biopolymer chitin. Duck eggshell (95% CaCO3) as starting material was converted to be calcium oxide (CaO) through calcinations with temperature 1000oC for 5 hours. In-situ and ex-situ methods were prepared from apatite and chitosan (dissolved with acetate acid 2%). Calcium phosphate prepared for bone implantation, but it is too fragile and brittle to be implant into the body. So addition of chitosan can decrease crystalinity and increase mechanic characteristic (tougher). Composite apatite-chitosan was resulted by fast precipitation. Fast precipitation was held in a breaker glass with nitrogen atmosphere, under controlled temperature at 37oC and pH 7, in order to increase amount of hydroxyapatite. Precipitation with CaO which was dropped by (NH4)2HPO4. Hydroxyapatite and chitosan were appearing at samples with in-situ and ex-situ methods which indicating by peak matching of XRD (closed lattice parameter, crystal size), overlapping at FTIR spectra and supporting by SEM picture (homogenous and agglomerated particle). However, it still needs further research to examine biocompatibility osteoconductive degree of sample by in-vivo and in-vitro test.
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Judul: Sintesis Komposit Hidroksiapatit dengan Variasi 10-50% Kitosan
Abstrak: In medical cases, HAp/chitosan composite can be used as a synthetic implantation in bone. Addition of chitosan on HAp seems produce good composite. Chitosan can reduce the properties of brittle HAp. XRD characterization on all samples showed that pattern has formed apatite dominated by the peak of HAp. The peak of chitosan on the results of XRD was not visible. It is due to chitosan has spread all over the samples. On FTIR characterization, the appearance of phosphate group and hydroxyl group show that HAp was identified in samples, while chitosan was indicated by the appearance of a group of NH, CO and CH. The results of observations with an optic stereo microscope, samples morphology showed that HAp was well distributed in chitosan. Test results of shore A test showed the addition of chitosan on HAp proved able to eliminate brittle properties of HAp. A lot of chitosan in the samples will reduce the hardness of the composition of the HAp / chitosan
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Judul: Memahami Kemacetan Kota Bogor Menggunakan Analisis Jalur
Abstrak: Kemacetan masih menjadi momok yang menakutkan bagi pengendara mobil di perkotaan, salah satunya adalah di Kota Bogor. Menurut survei yang dilakukan Waze (aplikasi navigasi dan lalu lintas) pada tahun 2016, Kota Bogor adalah kota paling tidak ramah kedua di dunia untuk pengemudi kendaraan. Penulis menggunakan aplikasi yang sama mencoba memahami lebih dalam apa yang menyebabkan kemacetan di Kota Bogor, dibantu dengan analisis jalur dapat terlihat bahwa Jalan Padjajaran (Lippo Plaza Kebun Raya – Tugu Kujang) memberikan kontribusi kemacetan secara langsung terbesar untuk Jalan Jalak Harupat. Jalan Otto Iskandardinata memberikan kontribusi kemacetan secara langsung terbesar pada rute Jalan Padjajaran (Lippo Plaza Kebun Raya – Tugu Kujang). Jalan Surya Kencana dan Jalan R. Saleh S. Bustaman memberikan kontribusi kemacetan secara langsung terbesar untuk Jalan Otto Iskandardinata. Jalan Jalak Harupat memberikan kontribusi kemacetan secara langsung terbesar untuk rute Jalan Ir H Juanda. Selain pengaruh langsung terdapat juga pengaruh tidak langsung dan faktor lain diluar model yang memengaruhi kepadatan lalu lintas di rute jalan primer di lingkar Kebun Raya Bogor. Faktor lain tersebut bisa jadi disebabkan oleh kendaraan yang masuk atau keluar melalui rute-rute jalan lain yang tidak terobservasi.
Keyword: analisis jalur, kemacetan, kota Bogor