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: Analisis Karakteristik Permukaan Kayu Jati (Tectona grandis L.) dengan Aplikasi Nanocoating Titanium Dioksida terhadap Weathering
Abstrak: Kayu jati (Tectona grandis L.) cepat tumbuh memiliki karakteristik yang inferior dibandingkan dengan jati rotasi panjang seperti stabilitas dimensi dan keawetan yang rendah sehingga dapat membatasi penggunaannya terutama untuk aplikasi eksterior. Teknologi pelapisan (coating) menggunakan bahan yang bersifat melindungi dari paparan UV seperti nano titanium dioksida (TiO2) perlu dilakukan. Penelitian ini bertujuan untuk menganalisis pengaruh perlakuan coating (jenis dan konsentrasi nano TiO2) dan periode weathering terhadap kekasaran permukaan dan keterbasahan kayu jati (Tectona grandis L.). Bahan coating yang digunakan yaitu varnish berpelarut air dan varnish berpelarut minyak. Adapun nanocoating terbuat dari campuran nano TiO2 dan varnish dengan konsentrasi masing-masing 1%, 5%, dan 10%. Parameter yang diuji meliputi kekasaran permukaan dan keterbasahan. Hasil penelitian menunjukkan kayu yang diberi perlakuan coating varnish air menyebabkan permukaan kayu lebih halus. Penambahan nano TiO2 pada varnish air menurunkan keterbasahan kayu lebih baik dibandingkan varnish minyak. Kekasaran permukaan dan keterbasahan seluruh kayu jati mengalami peningkatan setelah weathering 2 dan 4 bulan., Fast growing Teak wood (Tectona grandis L.) has inferior wood characteristics compare to long rotation teak wood, such as poor dimensional stability and durability, which can limit its use especially for exterior aplications. This requires the use of coatings technology with substances like titanium dioxide nanoparticles (TiO2) that are made specifically to block UV radiation. This study aims to analyze the effects of coating treatment (coating type and consentration of nano TiO2) and weathering period on the surface roughness and wettability of teak wood. Both oil-based and water-based varnish are utilized as coating materials. Any nanocoating is formed of varnish and nano-sized TiO2 particles, and each is applied separately at concentrations of 1%, 5%, and 10%. Parameters studied consisted of surface roughness and wettability. The results shows that wood treated with a water-based varnish makes the wood surface smoother than oil-based varnish. The wettability of wood is improved more by the addition of nano TiO2 to a water-based varnish than oil-based varnish. After 2 and 4 months of weathering, the surface roughness and wettability of all treated wood increased.
Keyword: nanocoating, surface roughness, teak, TiO2, wettability

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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