Judul: Wettability and Bonding Quality of Paints on Ten Tropical Woods Species
Abstrak: Surface properties of wood such as surface roughness, wettability and surface free energy (SFE) are important properties influencing further manufacturing process such as finishing or adhesive strength characteristics. The aim of this research was to determine surface properties such as surface roughness, SFE, and wettability of ten tropical woods and its effect to their bonding quality of paints. The woods tested in this study were fast-growing teak Biotrop variation, afrika, sungkai, mindi, merbau, durian, lamtoro, pulai, acacia and kempas. Wood surfaces were divided into unsanded and sanded using abrasive paper of 120 grits. SFE values were calculated based on the Rabel method. Wettability were measured by based on the contact angle between liquid paint and wood surface using sessile drop method and (S/G) model was used to evaluate the wettability of the surface coatings on the wood. Bonding quality of paints were measured using cross-cut test based on the ASTM 3359-02 standard. The results indicated that sanding decrease the surface roughness presented by Ra (arithmetical mean roughness), wettability and SFE of wood but produce higher equilibrium contact angle. Higher K-Value indicates higher wettability and bonding quality of paints. Afrika had greater wettability of acrylic and alkyd paints than the other wood species. Cross-cut tests showed that bonding quality of paints on ten wood species tend to decreased as the surface became smoother. The oil-based alkyd paint was more wettable and generates better bonding quality compared to the water-based acrylic paint.
Keyword: cat akrilik dan alkid, daya lekat, energi bebas permukaan, kekasaran permukaan, keterbasahan

Judul: Daya Tahan Lapisan Finishing Interior Pelarut Air pada Kayu Jati, Kamper, dan Pinus.
Abstrak: The limited supply of wood from natural forests makes markets interest to wood from plantation forest increase. However, the wood comes from plantation forests considered to be low in quality, including durability. Finishing is one of the solutions to overcome these problems. In this present day there has been developing water based finishing materials (waterbased finishes) that is safe for the environment and does not contain harmful chemicals that can threaten human health. A study has been conducted to determine the durability of the water based finishing layer (Impra Aqua and Sayerlack Waterborne) on Teak (Tectona grandis), Camphor (Dryobalanops aromatica), and Pine (Pinus merkusii). The type of testing conducted covers on the hot and cold test, resistance to household chemical materials, and cross-cut test. The test results showed that the finishing layer is resistant to the hot and cold test, thus can be classified into class 10 (with a completely unblemished surface). The Layer formed by Impra Aqua finishing material is also resistant to all household chemicals tested, so it is classified into class 10. Meanwhile the layer resistance of Sayerlack Waterborne finishing against ballpoint ink tend to be less powerful, so it is classified into class 9, but the finishing materials is resistant to chemicals such as Povidone-iodine. In the test results of paint adhesion (cross cut test), teak wood in wet conditions coated with both types of finishing materials has the weakest adhesion strength, so it is classified into class 3B. Meanwhile, finishing layer for all the wood samples under dry conditions have very strong adhesion, so it is classified in class 5B.
Keyword: Bogor Agricultural University (IPB), Sayerlack Waterborne, Impra Aqua, Hot and cold test, Cross cut test, Finishing, Waterbased

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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