Judul: Effect of Strand Pretreatment on Physical and Mechanical Properties of Oriented Strand Board from Sengon Wood (Paraserianthes falcataria (L.) Nielsen)
Abstrak: Penelitian ini bertujuan mengevaluasi karakteristik OSB kayu sengon dengan perlakuan pendahuluan steam dan steam bilas NaOH 1%. Strand kayu sengon diberi perlakuan steam pada suhu 126 ℃ dengan tekanan 0,14 MPa selama 1 jam dan dilanjutkan dengan pembilasan NaOH 1%. Strand dicampur dengan perekat Phenol Formaldehyde (PF) pada konsentrasi 10%. Papan berukuran (30x30x0,9) cm3 disusun 3 lapis dengan kerapatan target 0,55 g.cm-3 dan nisbah lapisan 25:50:25. Pengujian sifat fisis dan mekanis mengacu pada standar JIS A 5908 (2003) yang hasilnya dibandingkan dengan standar CSA 0437.0 (Grade O-1). Hasil penelitian menunjukkan bahwa perlakuan pendahuluan strand memberikan pengaruh terhadap stabilitas dimensi OSB. Perlakuan steam bilas NaOH 1% menghasilkan OSB dengan sifat fisis yang lebih baik dari perlakuan steam tanpa perlakuan lanjutan. Namun, perlakuan steam dan steam bilas NaOH 1% tidak berpengaruh terhadap sifat mekanis OSB. Secara keseluruhan, karakeristik OSB pada setiap perlakuan pendahuluan mampu memenuhi standar CSA 0437.0 (Grade O-1), terkecuali pada beberapa parameter sifat mekanis., The objectives of this research were to evaluated the characteristics of OSB from sengon wood with steam treatment and steam-treated followed by washing 1% NaOH. The sengon wood strand was treated with steam at a temperature of 126 ℃ with a pressure of 0,14 MPa for 1 hour and followed by washing with 1% NaOH. Strands were mixed with phenol formaldehyde (PF) adhesive at a concentration of 10%. Three layered of OSB was made with the size of (30x30x0,9) cm3, target density of 0,55 g.cm-3, and shelling ratio of 25:50:25. Testing of physical and mechanical properties of OSB refers to the JIS A 5908 (2003) standard and the results are compared with the CSA 0437.0 (Grade O-1) standard. The results show that the pretreatment of strand has an effect on the dimensional stability of OSB. The steam-treated follow by washing with 1% NaOH produce OSB with better physical properties than the steam without further treatment. However, the steam and steam-treated follow by washing with 1% NaOH has no effect on the mechanical properties of the OSB. Overall, the characteristics of OSB in each pretreatment met the CSA 0437.0 (Grade O-1) standard, prefix on some parameters of mechanical properties.
Keyword: kayu sengon, perlakuan pendahuluan, PF, OSB, pretreatment, sengon wood

Judul: Effect of Pre-treatment Technique on the Physical and  Mechanical Properties of Oriented Strand Board Made from Gmelina Wood  (Gmelina arborea Roxb) on Two Types of Adhesives
Abstrak: Tujuan dari penelitian ini adalah untuk mengevaluasi pengaruh steam pada strand terhadap sifat fisis dan mekanis OSB kayu gmelina pada dua tipe perekat. Strand kayu gmelina diberi perlakuan steam selama 1 jam pada suhu 126 °C dan tekanan 0,14 MPa. Oriented Strand Board kayu gmelina dibuat dengan kerapatan target 0,6 g.cm-3 dan menggunakan dua tipe perekat yaitu Methylene di-phenil di Isocyanate (MDI) dan Phenol Formaldehyde (PF). Kadar perekat yang digunakan sebesar 5% untuk MDI dan 10% untuk PF. Pengujian sifat fisis dan mekanis OSB mengacu pada standar JIS A 5908-2003 dan dibandingkan dengan standar CSA 0437.0 (Grade O-1). Hasil penelitian ini menunjukkan bahwa perlakuan steam pada strand dapat meningkatkan stabilisasi dimensi (menurunkan daya serap air dan pengembangan tebal) dan meningkatkan sifat mekanis (modulus of elasticity, modulus of rupture, internal bond, dan kuat pegang sekrup) OSB kayu gmelina. Oriented Strand Board kayu gmelina yang direkat oleh perekat MDI menghasilkan OSB yang lebih baik dibandingkan yang direkat oleh perekat PF., The objective of this study was to evaluated effect of steam on the strand on the physical and mechanical properties of oriented strand board made from gmelina Wood (Gmelina arborea Roxb) on two types of adhesives. Strand of gmelina wood were steamed at 126 °C and pressure of 0,14 MPa for 1 h. Gmelina wood OSBs were prepared with 0,6 g/cm3 target density and using two types of adhesives, namely Methylene di-phenil di-Isocyanate (MDI) and Phenol Formaldehyde (PF). The resin content used were 5% for MDI and 10% for PF. The physical and mechanical properties of the OSB were evaluated referring to the JIS A 5908-2003 standard and the values were compared with CSA 0437.0 (Grade O-1) standard. The result of this study indicate that the steam treatment on the strand can improve dimensional stabilization (reduce water absorption and thickness swelling) and increase the mechanical properties (modulus of elasticity, modulus of rupture, internal bond, and screw holding power) of gmelina wood OSBs. Gmelina wood OSBs bonded with MDI adhesives produced better OSB than bonded with PF adhesives.
Keyword: gmelina, Methylene di-phenil di-Isocyanate, OSB, phenol  formaldehyde, steam

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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