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: Ketahanan Oriented Strand Board Bambu terhadap Serangan Rayap dan Kumbang
Abstrak: INTRODUCTION. Bamboo is very promising to be used as OSB raw materials due to its excellent physical and mechanical properties. Unfortunately, naturally bamboo is also very susceptible to termite and beetles attack. In order to complete the information regarding the feasibility of using bamboo OSB for building component, the research associate with the resistance of OSB made from mixing bamboo against termite and powder post beetle attacked were observed. MATERIALS AND METHOD. Three layered OSBs were produced with the size of 30 cm x 30 cm x 1.0 cm. Three (3) bamboo species were used in this experiment ie., Betung bamboo (Dendr ocalamus asper Schult.F) Backer ex. Heyne), Andong bamboo (Gigantochloa verticillata (Willd.) Munro), and Ampel bamboo (Bambusa vulgaris Schrad. Ex Wendl.). Nine (9) c ombination of bamboo OSBs were prepared from these bamboos, namely 1) Betung/Betung/Betung; 2) Betung/Andong/Betung; 3) Betung/Ampel/Betung; 4) Andong/Andong/Andong; 5) Andong/Betung/Andong; 6) Andong/Ampel/Andong; 7) Ampel/Ampel/Ampel; 8) Ampel/Betung/Ampel; and 9) Ampel/Andong/Ampel. The density of OSB was around 0.7 g/cm3. Commercial MDI adhesive was used to bond the strands to OSB in amount of 5%. Four OSBs were prepared for each treatment. The resistances of bamboo OSBs against subterranean and dry wood termites were evaluated in accordance to Indonesia standard (SNI 01. 7207-2006). Meanwhile, the resistance of bamboo OSBs against powder post beetles was evaluated using semi-field test. RESULTS AND DISCUSSION. The results indicated that the resistance of bamboo OSBs against subterranean termite (Coptotermes curvignathus Holmgren) increased 2 times compared to the solid bamboo. All the bamboo solid used belongs to “poor” (level 4) and after converted into OSBs the resistance of bamboo OSBs increased to become “resistance” (level 2). Conversely, the resistance of bamboo OSBs against dry wood termite (Cryptotermes cynocephalus Light) attacked decreased 2 times compared to the solid bamboo. All the bamboo solid used belongs to “very resistance” (level 1) and after converted into OSBs the resistance of bamboo OSBs lowered to become “moderately resistance” (level 3). Based on the values of weight loss obtained, whether OSBs prepared from single species bamboo or mixing bamboos had similar resistance to C. curvignathus and C. cynocephalus attacked. It was observed that the species of powder post beetle attacked the bamboo OSBs was Anobium sp. The resistance of solid bamboo against Anobium sp was varied. The average weight loss of Betung bamboo, Andong bamboo and Ampel bamboo were 3.19%, 17.39% and 25.36%, respectively. The average weight losses of bamboo OSBs prepared in this experiment were in the range of 2.85- 3.87%. Andong bamboo and Ampel bamboo belong to very susceptible to Anobium sp attacked. After converted into bamboo OSBs their resistances were increased around 5 times. Whether OSBs prepared from single species bamboo or mixing bamboos had similar resistance to Anobium sp.
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Judul: Approximation of the Median of Poisson Distribution Using the Relation of Poisson-Gamma Distribution
Abstrak: A major drawback of median is that median cannot usually be defined in closed form, even in the cases where their distribution functions are known. This study gives an approximation of the closed form for the median of the Poisson distribution by using the relation of Poisson-Gamma distribution. The approximation uses elementary techniques based on the monotonicity of certain sequences involving tail probabilities of the Poisson distribution and the Central Limit Theorem. Furthermore, a closed form expression for the mean absolute deviation 􀜧|􀜰􀰒 􀵆 􀜯􀝁􀝀􁈺􀜰􀰒􁈻| is also studied. The median is relevant because of the fact that it minimizes the mean absolute deviation of a Poisson random variable (􀜰􀰒􁈻 by considering median as central tendency.
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