Judul: Persamaan Matematika Struktur Tegakan Horizontal Hutan Rakyat (Studi Kasus di Desa Parakanlima, Kecamatan Cikembar, Kabupaten Sukabumi, Jawa Barat).
Abstrak: Struktur tegakan horizontal adalah sebaran jumlah pohon persatuan luas (hektar) dalam berbagai kelas diameter. Pengelolaan hutan rakyat di Desa Parakanlima umumnya dilakukan dengan menggunakan sistem agroforestry. Penelitian ini bertujuan untuk memperoleh informasi bentuk persamaan matematika untuk struktur tegakan horizontal pada masing masing pemilik lahan hutan rakyat di Desa Parakanlima. Informasi ini diperlukan untuk memperoleh gambaran menggenai tingkat keteraturan pemanenan dengan pembinaan tegakan pohon pada setiap pemilik lahan hutan rakyat. Penelitian dilakukan di Desa Parakanlima, Kabupaten Sukabumi pada bulan Januari 2017 selama dua minggu. Hasil penelitian menunjukkan bahwa persamaan matematika yang dapat menggambarkan struktur tegakan horizontal pada hutan rakyat untuk setiap pemilik lahan di Desa Parakanlima adalah bentuk persamaan eksponensial negatif dan polinomial.
Keyword: hutan rakyat, persamaan matematika, struktur tegakan

Judul: Komposisi Jenis dan Persamaan Matematika untuk Struktur Tegakan Horizontal Hutan Rakyat di Desa Kalimendong
Abstrak: Stand structure can be used to identify the plantation characteristic. That is important for determining treatment of silviculture. This research purpose is to find out the information of mathematic equation in every private community forest in Kalimendong Village. This research was conducted in Kalimendong Village, Wonosobo Distrct in May 2014 (2 weeks). Data was collected using census method, where the measurement was done in every stands on private lands. Processed data was confined to dominating stands which is Sengon with 519 Sengon trees. Sengon’s variables is diameter and basal area presented in histogram. In order to explain more about stands distribution, data analyzed using normal distribution function. The result showed that the mathematic equation in every private land can be accepted with coefficient of determination (R²) more than 0.5 and p-value less than 0.05. Distribution form obtained from this research is polynomial function and negative exponential. Plantation characteristic specifically known from inverted bell curve but Sutarman and Waluyo land has inverted ‘’J’’ c
Keyword: Bogor Agricultural University (IPB), stands structure, mathematic equation

Judul: Hydroxyapatite-Chitosan Composite Coating on Stainless Steel 316 to Improve Corrosion Resistance
Abstrak: Metals that were used in bone implantation should have good corrosion resistance that were not easily corroded when implanted into the body. Metal corrosion resistance of stainless steel 316 can be enhanced through the metal coating by hydroxyapatite-chitosan composite with composition ratio of hydroxyapatite (gram) and chitosan 3% (mL) 0.2:0, 0.2:0.1, 0.2:0.5, 0.2:1.0, and 0.2:1.5. Besides improving the corrosion resistance of metal, the presence of chitosan also maintain the position of hydroxyapatite on metal surfaces. Corrosion resistance increases with increasing amount of chitosan added and the best composition of hydroxyapatite-chitosan composite was 0.2:1.0.
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