Judul: Surface Characteristics of Pinus merkusii and Pinus sylvestris Treated with Enborer After Graveyard Test
Abstrak: Kayu Pinus merkusii dan Pinus sylvestris banyak digunakan sebagai bahan baku produk interior maupun eksterior, namun kedua jenis pinus tersebut memiliki keawetan yang rendah. Pengawetan dengan enborer merupakan salah satu cara meningkatkan keawetan serta kualitas permukaan kayu. Penelitian ini bertujuan untuk menganalisis pengaruh bahan pengawet enborer terhadap karakteristik permukaan kayu Pinus merkusii dan Pinus sylvestris sebelum dan setelah uji kubur. Uji karakteristik permukaan kayu meliputi kekasaran permukaan, energi bebas permukaan (surface free energy-SFE), keterbasahan dan daya lekat cat. Hasil penelitian menunjukkan bahwa nilai kekasaran permukaan, SFE, dan keterbasahan kayu meningkat seiring dengan lamanya waktu uji kubur. Cat alkid memiliki daya lekat yang lebih baik dibandingkan dengan cat akrilik untuk semua perlakuan. Kayu Pinus merkusii terawetkan enborer memiliki nilai kekasaran permukaan, SFE, dan keterbasahan paling rendah. Pinus merkusii terawetkan enborer juga menunjukkan daya lekat yang kurang baik dibandingkan perlakuan kontrol., Pinus merkusii and Pinus sylvestris are widely used as raw materials for interior and exterior products, however both species of pine have low durability. Enborer preservation is one of the methods to improve the durability and surface quality of wood. This study aimed to analyze the effect of enborer preservative on the surface characteristics of P.merkusii and P.sylvestris before and after the graveyard test. The wood surface characteristics studied were surface roughness, surface free energy (SFE), wettability and bonding quality of paint. The results show that the values of surface roughness, SFE, and wood wettability increased as the longer of the graveyard test. Alkyd paint had better bonding quality than acrylic paint for all treatments. P.merkusii treated with enborer had the lowest surface roughness, SFE, and wettability values. P.merkusii treated with enborer also presented the lowest bonding quality.
Keyword: bonding quality, enborer preservative, Pinus merkusii, Pinus sylvestris, wettability

Judul: Surface Characteristics of Modified Scots Pine by DMDHEU (Dimethylol Dihydroxy Ethylene Urea) and Phenol Formaldehyde
Abstrak: Karakteristik permukaan kayu merupakan salah satu sifat yang mempengaruhi kualitas permukaan kayu terutama pada proses finishing. Kualitas kayu scots pine dapat ditingkatkan dengan teknik modifikasi kimia menggunakan Dimetilol Dihidroksi Etilen Urea (DMDHEU) dan Fenol Formaldehida (PF). Penelitian ini bertujuan mengevaluasi karakteristik permukaan kayu scots pine hasil modifikasi (PF resin, PF resin dengan bio-oil (PFO), DMDHEU resin (D), turunan DMDHEU resin bebas formaldehida (DE), DMDHEU resin dengan softener (DS), dan DMDHEU resin termodifikasi (MD)) setelah uji kubur selama 4, 8, dan 12 bulan. Modifikasi kayu menggunakan metode impregnasi. Hasil penelitian menunjukkan bahwa modifikasi kimia dan lama uji kubur berpengaruh terhadap karakteristik permukaan kayu. Nilai kekasaran permukaan, energi bebas permukaan (Surface Free Energy-SFE), keterbasahan, dan daya lekat cat meningkat seiring lama waktu uji kubur. Hasil uji SFE sebelum uji kubur memiliki nilai komponen polar yang lebih rendah, sedangkan setelah uji kubur nilai komponen polar meningkat dan lebih tinggi dibandingkan komponen dispersi. Nilai keterbasahan paling tinggi pada perlakuan DE dan nilai terendah pada perlakuan PF. Daya lekat cat alkid memiliki kualitas yang lebih baik dibandingkan dengan daya lekat cat akrilik., Wood surface characteristics are one of the properties that affect the surface quality, especially the finishing process. The quality of scots pine wood can be improved by chemical modification of using Dimethylol Dihydroxy Ethylene Urea (DMDHEU) and Phenol Formaldehyde (PF). This study aimed to evaluate the surface characteristics of scots pine chemically modified by PF, PF with bio-oil (PFO), DMDHEU (D), DMDHEU derivative of formaldehyde-free resin (DE), DMDHEU with softener (DS), and modified-DMDHEU (MD) after 4, 8, and 12 months graveyard tests. The wood modification method was impregnation. The results showed that chemical modification treatment and graveyard test affected the wood surface characteristic. The values of roughness, surface free energy (SFE), wettability, and bonding quality increased as longer period of the graveyard test. The SFE value before the graveyard test was a lower polar component, while after the graveyard test increased to be higher than the dispersion component. The wettability value of the DE treatment was higher than the other treatments, meanwhile the wettability of the PF treatment was the lowest. Alkyd paint had better bonding quality than acrylic paint.
Keyword: DMDHEU, graveyard test, PF, scots pine, surface characteristics

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