Judul: Surface Characteristics of Short Rotation Teak  Wood Chemical and Heat Modified and Weathering Tests
Abstrak: Modifikasi kimia dan panas merupakan alternatif untuk mengembangkan teknik peningkatan mutu kayu. Modifikasi kayu dengan bahan furfuril alkohol (FA) dan gliserol-maleat anhidrida (GMA) pada suhu 150 °C dan 220 °C terbukti dapat meningkatkan mutu kayu. Penelitian ini bertujuan menganalisis pengaruh modifikasi kimia dan panas terhadap karakteristik permukaan kayu jati rotasi pendek sebelum dan setelah weathering. Perlakuan yang dipakai dalam penelitian ini ialah impregnasi FA; impregnasi GMA diikuti dengan panas pada suhu 150 °C dan 220 °C; dan perlakuan panas suhu 220 °C. Hasil penelitian menunjukkan kayu yang diberi perlakuan panas menjadikan permukaan kayu yang lebih halus. Modifikasi kimia dan panas menyebabkan penurunan terhadap nilai energi bebas permukaan (Surface Free Energy-SFE). Nilai sudut kontak kayu jati perlakuan panas dan GMA suhu 220 °C lebih tinggi dibanding GMA suhu 150 °C. Cat alkid memiliki keterbasahan yang lebih baik daripada cat akrilik. Daya lekat cat alkid lebih baik dibanding dengan cat akrilik. Kayu jati rotasi pendek pada semua perlakuan mengalami peningkatan nilai keterbasahan setelah uji weathering selama 3 bulan., Chemical and heat modification are alternatives to develop wood quality improvement techniques. Modification of wood with furfuryl alcohol (FA) and glycerol-maleic anhydride (GMA) at 150 °C and 220 °C has been shown to improve wood quality. This study aims to analyze the effect of chemical and heat modification on the surface characteristics of short rotation teak before and after weathering. The treatments used in this study were impregnation with FA; impregnation with GMA followed by heat modification at 150 °C and 220 °C; and heat treatment at 220 °C. The results showed that heat treated wood made the surface of the wood smoother. Chemical and heat modifications caused the decrease in the value of surface free energy (SFE). The contact angle value of heat treated and GMA at 220 °C was higher than the GMA at 150 °C. Alkyd paints had a better wettability than acrylic paints. The bonding quality of alkyd paint also had a better than acrylic paint. Short rotation teak wood for all treatments increased in wettability value after 3 months of weathering.
Keyword: glycerol-maleic anhydride, heat modification, short rotation teak wood weathering, wood surface characteristics

Judul: Quality Improvement of Short Rotation Teak by Non-biocide Chemical and Thermal Modification
Abstrak: Jati rotasi pendek memiliki potensi besar untuk pemenuhan kebutuhan kayu bagi industri karena memiliki siklus tebang yang pendek (kurang lebih 15-20 tahun). Kayu yang dihasilkan dari pertumbuhan yang cepat umumnya memiliki mutu yang rendah sehingga membatasi pemanfaatannya. Upaya untuk mengatasi kelemahan pada kayu jati rotasi pendek dapat dilakukan melalui modifikasi kimia dan panas. Modifikasi kayu ramah lingkungan saat ini mulai dicobakan dan dikembangkan. Bahan kimia ramah lingkungan yang dapat meningkatkan mutu kayu yaitu asam sitrat (CA) dan benzophenone tetracarboxylic acid (BPTCA). Tujuan dari penelitian ini adalah menganalisa pengaruh modifikasi kimia dan panas terhadap sifat fisis, sifat mekanis, keawetan alami dan karakteristik permukaan kayu jati rotasi pendek. Kayu diimpregnasi menggunakan larutan CA dan BPTCA dengan konsentrasi 20% dan 40%. Proses impregnasi dimulai dengan pemberian tekanan 700 kPa selama 4 jam yang dilanjutkan dengan pemberian panas dengan suhu 150 °C selama 2 jam. Parameter yang diuji yaitu sifat fisis (retensi, weight percent gain (WPG), leaching, kadar air, kerapatan, anti swelling efficiency (ASE), dan water uptake (WU)), sifat mekanis (Modulus of Elasticity (MOE) dan Modulus of Rupture (MOR)), keawetan, kekasaran permukaan, sudut kontak kesetimbangan, surface free energy (SFE), keterbasahan dan daya lekat cat. Hasil penelitian menunjukkan bahwa nilai retensi dan WPG untuk CA dan BPTCA sudah memenuhi standar untuk penggunaan kayu interior maupun eksterior. Peningkatan kerapatan kayu jati termodifikasi berbanding lurus dengan peningkatan WPG. Modifikasi kimia dan panas dapat meningkatkan stabilitas dimensi dan menurunkan nilai kadar air. Namun, perlakuan modifikasi kimia dan panas ini dapat menurunkan nilai MOE dan MOR. Kayu termodifikasi CA dan BPTCA tahan terhadap serangan rayap. Modifikasi kimia dan panas berpengaruh pada karakteristik permukaan dan sudut kontak kesetimbangan. Nilai kekasaran permukaan semakin menurun setelah dimodifikasi sehingga mempengaruhi nilai keterbasahan dan SFE. Nilai keterbasahan kayu termodifikasi terhadap cat akrilik lebih rendah dibandingkan dengan cat alkid. Nilai SFE kayu jati menurun setelah perlakuan modifikasi. Kayu jati termodifikasi memiliki nilai SFE dengan komponen polar lebih rendah jika dibandingkan dengan dispersi. Daya lekat kayu termodifikasi menggunakan cat alkid menghasilkan kualitas lebih baik dibandingkan cat akrilik., Short rotation teak has a great potential to fulfill the need of industry due to its short cutting cycle (approximately 15-20 years). Woods coming from short rotation edge tend to produce low quality, which limite their utilization. An innovation technology to improve the quality of fast-growing teak wood is wood modification by chemical and thermal modification. Environmentally friendly wood modification is currently in great demand. Non-biocide chemicals used to improve the quality of short rotation teaks are citric acid (CA) and benzophenone tetracarboxylic acid (BPTCA). The purpose of this study was to analyze the effect of chemical and thermal modification on physical, modulus of elasticity, modulus of rupture, durability and surface characteristics of short rotation teak. Short rotation teak wood was impregnated by using 20% and 40% of CA and BPTCA solution. The impregnation process was initiated by applying 700 kPa pressure for 4 hours and followed by thermal modification at 150 °C for 2 hours. Parameters studied consisted of physical properties (retention, weight percent grain (WPG), leaching, moisture content, density, anti swelling efficiency (ASE) and water uptake (WU), mechanical properties
Keyword: chemical and thermal modification, dimensional stability, short rotation teak, surface characteristics, wood durability

Judul: A Continuous Vaccination Strategy in the SVIR Epidemic Model
Abstrak: Vaccination is conducted to minimize the spread of a disease. The vaccination is usually done several times within a fixed time interval. In the SVIR model, it is assumed that individuals do not get immediate immunity following a vaccination program. So according to process of vaccination on SVIR model, there are two strategies, i.e. the continuous vaccination strategy (CVS) and the pulse vaccination strategy (PVS). In this study, only the CVS strategy in epidemic model SVIR is considered. Results of the study indicate that dynamics of the CVS system depends on the basic reproductive number. If the basic reproductive number is less than one, then the disease-free fixed point is asymptotically stable. It means that the disease will eventually disappear from the population. Conversely, if the basic reproductive number is greater than one, then the endemic fixed point is asymptotically stable, which means that the disease will remain exist in the population. Simulation result shows that the vaccination would minimize the spread of disease by reducing the basic reproductive number. If the time for the vaccinated recipients to obtain the immunity, as well as a possibility of vaccinated recipients to be infected are neglected, then the disease will be eradicated. This condition is called an over-evaluating effect of vaccination.
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