Judul: Physical and Mechanical Properties of Polystyrene Impregnated Glulam in Manii
Abstrak: Glulam (glued laminated timber) merupakan salah satu produk biokomposit yang dapat digunakan untuk mengatasi penggunaan kayu cepat tumbuh pada hutan tanaman. Kayu manii (Maesopsis eminii) merupakan salah satu jenis kayu cepat tumbuh yang dapat dimanfaatkan sebagai bahan baku glulam. Glulam dengan bahan baku kayu cepat tumbuh memiliki sifat fisis dan mekanis yang rendah. Untuk memperbaiki sifat fisis dan mekanis glulam kayu manii dapat dilakukan dengan impregnasi polistirena. Tujuan dalam penelitian ini adalah untuk mengetahui pengaruh proses impregnasi polistirena terhadap sifat fisis dan mekanis glulam dari kayu manii. Parameter sifat fisis dan mekanis yang diukur pada penelitian ini adalah kadar air, kerapatan, MOE, MOR, keteguhan geser, dan kekerasan. Nilai polymer loading yang terpolimerisasi dalam kayu sebesar 9,19%. Nilai kadar air berkisar antara 8,76 - 12,9%. Nilai kerapatan berkisar antara 0,42 - 0,47 g·cm-3. Nilai MOE berkisar antara 46607 - 66216 kg·cm-2. Nilai MOR berkisar antara 457 - 604 kg·cm- 2. Nilai keteguhan geser berkisar antara 67,91-46,08 kg·cm2. Nilai kekerasan berkisar antara 185 - 309 kg·cm-2. Nilai delaminasi glulam terimpregnasi polistirena lebih rendah dibanding glulam kontrol sebesar 6,22%. Secara keseluruhan hasil perlakuan impregnasi polistirena dapat meningkatkan sifat fisis dan mekanis glulam kayu manii., Glulam (glued laminated timber) is one of the biocomposite products that can be used to overcome the use of fast-growing wood in plantation forests. Manii (Maesopsis eminii) is a fast-growing species that can be used as raw material for glulam. Glulam with fast-growing species as raw material has low physical and mechanical properties. To improve the physical and mechanical properties of manii glulam can be done with polystyrene impregnation. The purpose of this study was to determine the effect of the polystyrene impregnation process on the physical and mechanical properties of glulam from manii wood. Parameters of physical and mechanical properties measured were moisture content, density, MOE, MOR, shear strength, and hardness. The polymer loading value in wood is 9.19%. The value of moisture content ranges from 8.76 - 12.9%. Density values ranged from 0.42 - 0.47 g·cm-3. MOE values ranged from 46607 - 66216 kg·cm-2. MOR values ranged from 457 - 604 kg·cm-2. The value of shear strength ranged from 67.91 - 46.08 kg·cm-2. Hardness values ranged from 185 - 309 kg·cm-2. The delamination value of polystyrene impregnated glulam was lower than that of control glulam by 6.22%. Overall the results of polystyrene impregnation treatment can improve the physical and mechanical properties of manii glulam.
Keyword: glulam, impregnation, isocyanate, manii wood, polystyrene

Judul: Physical and Mechanical Properties of Jabon Wood Glulam (Anthocephalus cadamba Miq.) Impregnated with Polystyrene
Abstrak: Kondisi pohon cepat tumbuh memiliki sifat dan mutu yang rendah. Penelitian ini bertujuan meningkatkan kualitas sifat fisis dan mekanis glulam kayu jabon dengan perlakuan impregnasi polistirena. Impregnasi dilakukan dengan metode vakum sebesar 60 cmHg dan ditekan sebesar 10 kg.cm-2 masing-masing selama 30 menit. Glulam dibuat berukuran 1,6 x 5 x 80 cm3 (tebal x lebar x panjang) dan direkatkan menggunakan perekat isosianat dengan berat labur sebesar 280 g.m-2. Setelah itu dikempa dengan tekanan spesifik 67,8 J selama 3 jam. Pengujian sifat fisis, mekanis dan delaminasi mengacu pada JAS 234: 2003. Hasil pengujian kadar air dan kerapatan berturutturut berkisar antara (11,43-12,70) % dan (0,31-0,37) g.cm-3, sedangkan Modulus of Elasticity (MOE), Modulus of Rupture (MOR), keteguhan rekat, dan kekerasan (Hardness) berturut-turut sebesar (45.211-93.378) kg.cm-2, (372-389) kg.cm-2, (42-53) kg.cm-2, (172-253) kg.cm-2 dan pengujian delaminasi berkisar (2,52-3,00) %. Perlakuan impregnasi polistirena dapat meningkatkan sifat fisis glulam tetapi tidak sifat mekanisnya, sehingga glulam terimpregnasi polistirena tidak cocok untuk konstruksi berat melainkan untuk konstruksi ringan. Glulam perlakuan kontrol memiliki sifat mekanis yang lebih baik jika dibandingkan dengan glulam terimpregnasi polistirena dan kayu solid., The condition of fast-growing trees has low quality and character. The objective of this research was to improve the quality of the physical and mechanical properties of jabon wood glulam with polystyrene impregnation treatment. Impregnation was carried out using a vacuum method of 60 cmHg and pressed by 10 kg.cm-2 for 30 minutes each. Glulam was made with a size 1.6 x 5 x 80 cm3 (thickness x width x length) and glued using isocyanate adhesive with a weight of 280 g.m-2. Then compressed with a specific pressure of 67.8 J for 3 hours. Testing of physical, mechanical and delamination properties refers to JAS 234: 2003. The results of the moisture content and density tests ranged from (11,43-12,70) % and (0,31-0,37) g.cm-3. Meanwhile, the Modulus of Elasticity (MOE), Modulus of Rupture (MOR), adhesive strength, and Hardness are (45.211-93.378) kg.cm-2, (372-389) kg.cm-2, (42-53) kg.cm-2, (172-253) kg.cm-2 and the delamination test ranges from (2,52-3,00) %. Polystyrene impregnation treatment can improve the physical properties of glulam but not its mechanical properties, so polystyrene impregnated glulam is not suitable for heavy construction but for light construction. Control treated glulam had better mechanical properties when compared to polystyrene impregnated glulam and solid wood.
Keyword: fast growing wood, glulam, jabon, impregnation, polystyrene

Judul: Dynamical System of Hepatitis B in Three Groups with Vaccination
Abstrak: The aim of this study is to modify the hepatitis B transmission model in three age groups involving vaccination from the model conducted by Zhoe and Zhang.The method used is to analyze the stability of the fixed point and its basic reproduction number (R_0). Performed stability analysis and numerical simulation to see population dynamics. Next, a sensitivity analysis of the parameters was carried out to see its effect on R_0. From the analysis obtained two fixed points, namely non-endemic and endemic fixed points. Non-endemic fixed points are locally asymptotically stable if R_0 <1 Meanwhile, the endemic fixed point is locally asymptotically stable if R_0 > 1. Hepatitis vaccination affects the number of susceptible population, because the more successful the vaccination, the smaller the number of susceptible populations so that the smaller the population will be infected.
Keyword: Dynamic, Hepatitis B, Vaccine, Mathematical model