Judul: Characterization of CoCrMo alloy with titanium nitride and hydroxyapatite-chitosan coating
Abstrak: Endoprosthetic is moving tool for implant in the body, made of metals or polymers. Stainless steel, Co-based alloys, and Ti materials are widely used for implant materials. Co alloy used is CoCrMo which has excellent properties such as good biocompatibility, corrosion resistant, good mechanical properties such as hardness, strength, and high wear resistance, supporting its utilization as an implant material. CoCrMo alloy was synthesized using tri arc furnace with heating temperature of 3000 °C. TiN coating using plasma sputtering and nitriding method, characterized by a layer of gold. The content of Ti in the layer was 3.85% (w/w), whereas the content N was difficult to determine. Hydroxyapatite (HAp) was synthesized using wet method with Ca source of chicken eggshell and P source of H3PO4 80%. HAp-chitosan composite coating aimed at improving the biocompatibility and corrosion resistance of CoCrMo. In vitro test showed that CoCrMo with TiN and HAp-chitosan coating had excellent corrosion resistance in liquid medium infusion, whereas samples HAp and CoCrMo with TiN coatings and HAp-chitosan had high level of toxicity in endothelial cell culture tests.
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Judul: Optimisasi Penyalutan Hidroksiapatit pada Paduan CoCrMo denganMetode Elektroforesis Deposisi
Abstrak: CoCrMo alloy has good biocompatibility and so it can be used as a substitute for bone damage (implant). However, other material isneeded to improve the biocompatibility of the CoCrMo. Hydroxyapatite can be used to coat the CoCrMo alloys to improve the biocompatibility of the CoCrMo. Hydroxyapatite can stimulate the growth of bone tissue surrounding the implant. Coating hydroxyapatite on the CoCrMo alloys was carried out using electrophoreticdeposition method by varying a number of variables, i.e. ratio of solution volume (ethanol-triethanolamine), pH, voltage, and time. The use of such variables was intended to get an optimum condition of the CoCrMo alloy coating. Test on the strength of hydroxyapatite layer in NaCl 0.9% infusion solutionshowed an optimum coating at pH 7, voltage 120V, for 30 minutes with a ratio of ethanol:TEA (50:2) mL.The test was done by soaking the hydroxyapatite-coated metal in 0.9% NaCl for 5 hours.Identification in phase diffraction conformedthe diffraction pattern as JCPDS hydroxyapatite.
Keyword: hydroxyapatite., CoCrMo alloy, electrophoretic deposition

Judul: Komparasi Distribusi Spasial Pemetaan Gambut Tahun 1970-an dengan KHG di Wilayah Sumatera Selatan
Abstrak: Perlindungan dan pengelolaan ekosistem gambut termasuk luas dan sebaran gambut diatur dalam Peraturan Pemerintah No. 71 Tahun 2014 juncto PP No. 57 Tahun 2016. Kemudian dari pada itu Kesatuan Hidrologis Gambut (KHG) diatur oleh Menteri Lingkungan Hidup dan Kehutanan (LHK) dalam Permen LHK No. 14 Tahun 2017. Melalui SK MENLHK No. 129 Tahun 2017, Peta Kawasan Hidrologis Gambut (KHG) Nasional dengan skala 1:250.000 ditetapkan. Meskipun luasan dan batas-batas KHG diatur oleh pemerintah, namun dianggap masih kurang akurat. Luasan sebaran gambut yang tercantum dalam lampiran Peraturan Pemerintah tersebut memiliki perbedaan yang signifikan dengan kondisi sebenarnya di lapang. Oleh karena itu, perlu dilakukan perbandingan luasan dengan peta-peta terdahulu salah satunya dengan peta hasil survei dan pemetaan tanah Proyek Pembukaan Persawahan Pasang Surut (P4S) yang dilakukan oleh Tim Survei IPB tahun 1970- an skala pemetaan semi detail yaitu 1:50.000. Area studi penelitian ini berfokus pada lahan gambut yang terletak di Provinsi Sumatera Selatan. Hasil penelitian menunjukan bahwa distribusi KHG pada area studi memiliki luas 445.676 Ha (73,42%) dengan Fungsi Lindung Ekosistem Gambut (FLEG) seluas 268.939 Ha (44,29%) dan Fungsi Budidaya Ekosistem Gambut (FBEG) 176,737 Ha (29,13%). Sedangkan distribusi gambut berdasarkan hasil survei dan pemetaan P4S hanya memiliki luas 137.670 Ha (22,6%). Hasil komparasi antara kedua peta menunjukkan bahwa terdapat perbedaan luas, peta KHG lebih luas 3 kali lipat dari peta distribusi gambut hasil P4S. Hal ini menunjukkan bahwa adanya kelemahan dan ketidakakuratan penarikan batas-batas KHG pada area studi.
Keyword: ambut, KHG, hasil survei P4S, perbedaan luas, satuan peta