Judul: Effectiveness of Boron Compound and Vegetable Oil Treatment in Increasing the Resistance of Gombong Bamboo (Gigantochloa pseudoarundinaceae) from Termite Attack
Abstrak: Bambu merupakan bahan yang sangat potensial dalam industri furniture dan kerajinan, karena pertumbuhannya yang cepat serta sifat fisis dan mekanisnya yang baik. Namun, kerentanannya terhadap serangan organisme perusak, terutama rayap memerlukan pengawetan untuk meningkatkan masa pakainya. Penelitian ini bertujuan mengevaluasi ketahanan bambu gombong dari serangan rayap tanah dan rayap kayu kering setelah diberi perlakuan impregnasi boron acid equivalent (BAE), pemanasan, dan minyak nabati. Pemanasan dilakukan pada suhu 60 °C, 150 °C dan 180 °C. Pengujian ketahanan terhadap rayap tanah dan kayu kering dilakukan mengacu pada SNI 7207:2014. Perlakuan BAE, minyak mimba, dan kombinasi BAE dengan minyak nabati (rami dan mimba) mampu meningkatkan ketahanan bambu gombong dari serangan rayap tanah dan rayap kayu kering. Kombinasi minyak mimba dengan pemanasan suhu 180 °C menghasilkan peningkatan bambu gombong paling baik pada pengujian rayap tanah. Kombinasi BAE dan minyak mimba pada pemanasan 180 °C menghasilkan peningkatan ketahanan bambu gombong paling baik pada pengujian rayap kayu kering., Bamboo is a highly potential material in the furniture and handicraft industries, due to its rapid growth and good physical and mechanical properties. However, its susceptibility to attack by destructive organisms, especially termites, requires preservation to increase its service life. This study aimed to evaluate the resistance of gombong bamboo to subterranean and dry wood termites attacks after being treated with boric acid equivalent (BAE) impregnation, heating, and vegetable oil. Heating was carried out at 60 °C, 150 °C, and 180 °C. The resistance testing against subterranean and dry-wood termites were carried out following SNI 7207:2014 The treatment of BAE, neem oil, and the combination of BAE with vegetable oils (linseed and neem) increased the resistance of gombong bamboo from subterranean termites and dry-wood termites. The combination of neem oil with 180 °C heating resulted in the best improvement of gombong bamboo in subterranean termite testing. The combination of BAE and neem oil at 180 °C heating produced the best increase in gombong bamboo resistance in dry-wood termite testing.
Keyword: bambu, minyak nabati, pemanasan, pengawetan, senyawa boron

Judul: Ketahanan Oriented Strand Board Bambu dengan Perlakuan Steam dan Non Steam terhadap Serangan Rayap dan Kumbang Bubuk
Abstrak: The objectives of this research were to evaluate the resistance of bamboo oriented strand board (BOSB) made from several bamboo species with or without steam treatment against subterranean termite (Coptotermes curvignathus), dry wood termite (Cryptotermes cynocephalus) and powder post beetle attacked. Five (5) bamboo species namely betung, andong, ampel, hitam, and tali bamboos were obtained from Sukabumi. Prior to be mixed with adhesive, part of bamboo strands were steamed in autoclave at 126 °C, 1,4 kg/cm2 pressure for 1 h. Three layered OSBs were produced. The strand composition for face, core, and back was 25%, 50% and 25%, respectively. Commercial Phenol Formaldehyde (PF) adhesive in amount of 10% was used to bond the strands to BOSB. The results indicated that the resistance of solid bamboo was varied among species against C. curvignathus. The resistance of BOSB prepared both from steamed and non steamed bamboo strands were much higher compared to solid bamboo. The resistance of BOSB prepared from steamed bamboo strands was higher than non steamed bamboo strands. The resistance of solid bamboo against C. cynocephalus much depended on the presence of bark in the specimen tested. After converted into BOSBs, the resistances of all BOSBs with or without steamed treatment were much improved. The resistance of solid bamboo was varied among species against powder post beetle. After converted into BOSBs, the resistance of all BOSBs with or without steamed treatment were increased significantly compared to solid bamboo. It was observed that powder post beetle species attacked the specimen in this experiment is Anobium sp.
Keyword: subterranean termite, steam, powder post beetles, oriented strand board, drywood termite

Judul: Metrik Einstein (Anti-) Self-Dual Berdimensi Empat dengan Metode Cartan
Abstrak: Gravitational field equation can be formulated in differential forms (differential geometry), which describes gravity as a manifestation of the curvature of space-time. Curvature of space-time is characterized by a metric that satisfies the gravitational field equation. With differential forms it can be formulated the (anti-) self-dual Einstein equation, which is a modification of the Cartan structure in (anti-) self-dual basis. Calculation of (anti-) self-dual metric with (anti-) self-dual Einstein equation is simpler than the calculation using Christoffel symbols.
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