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: Physical Properties and Color Changes in Polystyrene Impregnated Rubber Wood Glulam (Hevea brasiliensis)
Abstrak: ABSTRAK AZMAL ICHSANUL JOHAN. Sifat Fisis dan Perubahan Warna pada Glulam Kayu Karet (Hevea brasiliensis) Terimpregnasi Polistirena. Dibimbing oleh YUSUF SUDO HADI. Kayu merupakan bahan utama pada konstruksi bangunan perumahan, terutama untuk perumahan sederhana, Kayu karet merupakan salah satu kayu bermutu rendah yang berpotensi dan bisa dimanfaatkan untuk bahan baku glulam. Tujuan penelitian ini adalah untuk mengetahui pengaruh proses impregnasi polistirena terhadap sifat fisis dan perubahan warna glulam dari kayu karet (Hevea brasiliensis). Perlakuan impregnasi merupakan salah satu teknologi peningkatan mutu kayu yang dapat mengatasi atau memperbaiki kelemahan karakteristik kayu. Glulam dibuat menggunakan perekat isosianat dengan berat labur 280 g·m-2. Penilaian karakteristik yang dilakukan antara lain polymer loading, kerapatan, kadar air, delaminasi, dan perubahan warna. Nilai rata – rata polymer loading, kerapatan, kadar air, delaminasi dan perubahan warna masing – masing yaitu 6,89 %; 0,67 – 0,74 g·cm-3; 8,19 – 11,25 %; 29,13 – 32,36 %; dan 2,04 ± 1,20. Glulam terimpregnasi polistirena memiliki nilai sifat fisis yang lebih baik dibandingkan dengan kayu tanpa impregnasi polistirena. Nilai kerapatan tertinggi dan kadar air yang memenuhi standar JAS 234 didapatkan oleh glulam terimpregnasi polistirena. Glulam terimpregnasi polistirena memiliki nilai sifat fisis yang lebih baik dibandingkan tanpa impregnasi polistirena. Nilai delaminasi glulam impregnasi stirena memiliki standar deviasi yang tinggi. Perubahan warna kayu karet setelah impregnasi berubah menjadi lebih cerah setelah terimpregnasi polistirena. Kata kunci: glulam, impregnasi, isosianat. kayu karet, polistirena, ABSTRACT AZMAL ICHSANUL JOHAN. Physical Properties and Color Changes in Polystyrene Impregnated Rubber Wood Glulam (Hevea brasiliensis). Supervised by YUSUF SUDO HADI. Wood is the main material in the construction of residential buildings, especially for simple housing, rubber wood is one of the low-quality wood that has the potential and can be used as raw material for glulam. The purpose of this study was to determine the effect of the polystyrene impregnation process on the physical properties and color changes of glulam from rubber wood (Hevea brasiliensis). Impregnation treatment is one of the wood quality improvement technologies that can overcome or improve the weakness of wood characteristics. Glulam was made using isocyanate adhesive with a bulk weight of 280 g·m-2. Characteristics assessment carried out included polymer loading, density, moisture content, delamination, and color change. The average value of polymer loading, density, moisture content, delamination and color change are 6.89 %; 0.67 – 0.74 g·cm-3; 8.19 – 11.25 %; 29.13 – 32.36 %; and 2.04 ± 1.20. Glulam impregnated with polystyrene has better physical properties than wood without impregnated polystyrene. The highest density values and water content that met the JAS 234 standard were obtained by polystyrene impregnated glulam. Glulam impregnated with polystyrene has better physical properties than without impregnated polystyrene. The delamination value of styrene impregnated glulam has a high standard deviation. The color change of rubber wood after impregnation changes to a brighter color after impregnation with polystyrene.
Keyword: glulam, impregnation, isocyanate, polystyrene, rubber wood

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