Judul: Characteristics of Impregnated Fast Growing Woods by Nano Silica Orignated from Betung Bamboo Leaves and  Monoethylen Glycol.
Abstrak: Sengon (Paraserianthes falcataria L. Nielsen.) dan Jabon (Anthocephalus cadamba Miq.) merupakan jenis pohon cepat tumbuh yang memiliki nilai kekuatan, keawetan, kerapatan, dan stabilitas dimensi yang rendah. Salah satu metode untuk meningkatkan nilai dari kayu cepat tumbuh yaitu dengan cara impregnasi. Proses impregnasi dimulai dengan pemberian vakum 0,5 bar selama 60 menit dan dilanjutkan dengan pemberian tekanan 2,5 bar selama 120 menit. Perlakuan MEG dan nano silika mampu meningkatkan nilai persentase weight percent gain, kerapatan, perubahan warna, modulus of elasticity, modulus of rupture, kekerasan, meningkatkan nilai mortalitas serta menurunkan persentase kehilangan berat pada pengujian rayap kayu kering, rayap tanah dan uji lapangan kayu sengon serta kayu jabon. Perlakuan MEG dan nano silika juga dapat meningkatkan kelas kuat kayu sengon yang semula berada pada kelas kuat III-IV menjadi kelas kuat III dan kelas kuat kayu jabon yang semula berada pada kelas kuat IV-V menjadi kelas kuat V. Kelas awet kayu sengon yang semula berada pada kelas awet V menjadi II dan untuk kayu jabon yang semula berada pada kelas awet V menjadi kelas awet II., Sengon (Paraserianthes falcataria L. Nielsen.) and Jabon (Anthocephalus cadamba Miq.) are fast-growing tree species that have low strength, durability, density, and dimensional stability values. One method to increase the value of fast growing wood is by impregnation. The impregnation process was started by applying a vacuum of 0,5 bar for 60 minutes and continued by applying a pressure of 2,5 bar for 120 minutes. In drywood termites, subterranean termites, and field tests of sengon wood and jabon wood, MEG and nano silica treatments were able to increase the values of weight percent gain, density, color change, modulus of elasticity, modulus of rupture, hardness, increase the mortality value, and reduce the percentage of weight loss in drywood termites and subterranean termites. MEG and nano silica treatment can also increase the strength class of sengon wood, which was originally in strong class III-IV to be strong class III, and the strong class of jabon wood, which was originally in strong class IV-V to be strong class V. Sengon wood, which was originally in durable classes V to II, and jabon wood, which was originally in durable classes V to durable class II.
Keyword: daun bambu betung, impregnasi, jabon, nano silika, sengon, bamboo betung leaves, impregnation, nano silica

Judul: Physical and Mechanical Properties and Durability of Impregnated Fast-Growing Wood by Nano Silica from Bamboo Betung Sticks
Abstrak: Sengon (Paraserianthes falcataria L. Nielsen.) dan Jabon (Anthocephalus cadamba Miq.) merupakan jenis pohon cepat tumbuh yang memiliki kualitas kayu yang rendah dalam hal kekuatan, keawetan, kerapatan, stabilitas dimensi serta memiliki porsi kayu juvenile yang tinggi. Tujuan penelitian, menganalisis pengaruh perlakuan impregnasi MEG (Monoethylene Glycol) dan nano silika batang bambu terhadap sifat fisis, sifat mekanis dan keawetan kayu cepat tumbuh. Larutan impregnan yang digunakan terdiri dari kontrol (tanpa perlakuan), MEG, MEGSilika 0,5%, MEGSilika 0,75% dan MEGSilika 1%. Proses impregnasi dimulai dengan pemberian vakum 0,5 bar selama 60 menit dan dilanjutkan dengan pemberian tekanan 2,5 bar selama 120 menit. Hasil penelitian menunjukan bahwa perlakuan impregnasi MEG dan nano silika mampu meningkatkan kerapatan, Modulus of Elasticity (MOE), Modulus of Rupture (MOR), kekerasan, perubahan warna (ΔΕ), dan mortalitas rayap kayu kering kayu cepat tumbuh. Perlakuan MEG dan nano silika juga mampu menurunkan persentase kehilangan berat pada pengujian rayap kayu kering dan uji kubur kayu sengon serta kayu jabon. Hasil pengujian berbanding lurus dengan nilai weight percent gain (WPG). Perlakuan MEGSilika 1% menunjukan nilai yang paling optimum untuk kayu sengon dan kayu jabon., Sengon (Paraserianthes falcataria L. Nielsen.) and Jabon (Anthocephalus cadamba Miq.) are fast growing tree species that have low wood qualities in terms of strength, durability, specific gravity, dimensional stability and high portion of juvenile wood. The purpose of this study was to analyze MEG (Monoethylene Glycol) and nano silica of bamboo betung sticks impregnation treatments on physical and mechanical properties and durability of fast-growing wood. The solutions were consisted of control (water treated), MEG, MEGSilica 0.5%, MEGSilica 0.75% and MEGSilica 1%. The impregnation process was initiated by applying a vacuum of 0.5 bar for 60 minutes and continued by 2,5 bar pressure for 120 minutes. The results showed that MEG and nano silica impregnation increased the specific gravity, Modulus of Elasticity, Modulus of Rupture, hardness, color change (ΔΕ), and drywood termite mortality of treated fast growing wood. MEG and nano silica treatments also reduced weight loss percentage in the dry wood termite test and graveyard test of treated sengon and jabon wood. The test results are directly proportional to the weight percent gain (WPG) value. MEGSilica 1% treatment was the most optimal treatment for sengon wood and jabon wood.
Keyword: batang bambu betung, impregnasi, jabon, nano silika, sengon, bamboo betung sticks, impregnation, nano silica

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