Judul: Mechanical Properties and Durability of Impregnated Ganitri and Jabon Wood by Melamine Formaldehyde Furfuril Alcohol and Nano-SiO2
Abstrak: Ganitri (Elaeocarpus sphaericus (Gaertn.) K. Schum.) dan Jabon (Anthocephalus cadamba) adalah jenis kayu cepat tumbuh yang memiliki kelas kuat dan keawetan yang rendah. Salah satu metode untuk meningkatkan sifat mekanis dan keawetan dari kayu cepat tumbuh yaitu impregnasi. Penelitian ini bertujuan untuk menganalisis pengaruh impregnasi dengan campuran kopolimer Melamin Formaldehida Furfuril Alkohol (MFFA) dengan Nano-SiO2 0,5% terhadap sifat mekanis dan keawetan pada kayu ganitri dan jabon. Proses impregnasi secara menyeluruh dilakukan selama 3 jam dengan pemberian tekanan 0,5 bar pada 1 jam pertama dan dilanjutkan dengan pemberian tekanan 2 bar selama 2 jam. Hasil penelitian menunjukkan impregnasi dengan MFFA dan Nano-SiO2 dapat meningkatkan sifat mekanis dan keawetan secara optimum pada kayu ganitri dan jabon.
Keyword: ganitri, impregnation, jabon, MFFA, Nano-SiO2

Judul: The Improvement of Fast-Growing Wood Species Physical Properties through Impregnation of nano-SiO2
Abstrak: Nano-SiO2 based wood polymer composites are from impregnation of nano-SiO2 and melamine formaldehyde-furfuryl alcohol (MFFA) copolymers. This study aimed at analyzing the impregnation of a mixture of nano-SiO2 and MFFA copolymers on the properties of jabon and ganitri wood and explaining characteristics of jabon and ganitri wood after the process. The result showed that impregnation process could increase the physical parameters of jabon and ganitri wood. The wood density of jabon has risen from 0.32 to 0.56 g /cm3 , and that of ganitri wood has increased from 0.41 to 0.62 g /cm3 . Both weigt percen gaint of jabon and ganitri wood has risen by 68.34%, and 65.73%. The anti swelling efficiency jabon and ganitri has also increased by 46.66% and 70.19%.In addition, the bulking effect of jabon and ganitri wood was risen by 7.55% and 7.74%. The water uptake Jabon was decreased from 219.79% to 75.49%, and ganitri has also reduce from 86.4% to 45.32%. Wood characteristics identification after the impregnation process with nano-SiO2 and MFFA was using FTIR and XRD. The FTIR study showed that the peak of absorption shifted to a higher wave number on wood impregnated with nano-SiO2. The XRD study verified that there was a decrease in the crystallinity of wood cellulose. The presence of MFFA and nano-SiO2 polymers in the wood cell walls and cell lumen was detected using the Scanning Electron Microscopy (SEM). The results of physical properties and characterization tests with FTIR, XRD and SEM showed that jabon and ganitri impregnated with nano-SiO2 0.5% and MFFA are the optimal combinations.
Keyword: impregnation, fast-growing species, MFFA copolymer, nano-SiO2, physical properties

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