Judul: Angka bentuk dan model volume Kayu afrika (Maesopsis eminii Engl) di Hutan Pendidikan Gunung Walat, Sukabumi, Jawa Barat^
Abstrak: Some volume models and form factors have been developed for several trees species in Gunung Walat University Forest (GWUF), but no volume model and form factor are available yet for Maesopsis eminii. The objective of this study was to determine form factor and to develop volume model for M. eminii in GWUF. Eighty seven sample trees were used to develop volume models and 37 sample trees were used to validate the volume models, which were purpossively selected from the M. eminii stands with diameters ranging from 5.7 to 73.5 cm. The measurements of sample trees were conducted by using a Laser Criterion (for measuring tree diameter) and Laser Rangefinder (for measuring tree height). The results showed that M. eminii had an absolute form factor of 0.562 and an artificial form factor of 0.699, while the best model for estimating its volume was V = 0.000264D2.35. This volume model provided better precision (with a bias of 0.032) than the use of form factors.
Keyword: Bogor Agricultural University (IPB), Gunung Walat University Forest, volume model, Maesopsis eminii, form factor

Judul: Model Penduga Volume Pohon Mahoni Daun Besar (Swietenia macrophylla, King) di Hutan Pendidikan Gunung Walat, Sukabumi, Jawa Barat
Abstrak: Tree volume is one of the important data to determine the potential of wood in Gunung Walat Educational Forest. This research aims to obtain estimator model for the commercial volumes of the big leaf mahogany (Swietenia macrophylla King), either volume estimator model for the commercial unbranched tree or volume estimator model for the commercial branched tree. The largest correlation coefficient value between the breast height diameter and tree volume was in the commercial unbranched tree category, that was 0.981. The conditions of big leaf mahogany trees caused many differences of derived volume estimator models. From the results of the validation test, it obtained two volume estimator models with the same good level of reliability, those were V = 0.00010992D2.319 to estimate stem volume in the commercial unbranched of big leaf mahogany tree and V = 0.00015792 D2.314 to estimate the total volume in the branched commercial of large leaf mahogany tree. Both volume estimator models can be used to estimate the volume of big leaf mahogany trees in Gunung Walat Educational Forest.
Keyword: Bogor Agricultural University (IPB), volume estimation models, big leaf mahogany

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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