Judul: The Jatropha Hulls (Jatropha curcas L.) as an Alternative Raw Material of Particle Board
Abstrak: Jarak pagar (Jatropha curcas Linn) selain dikenal oleh masyarakat sebagai tanaman obat ternyata juga merupakan tanaman potensial penghasil BBM alternatif pengganti solar, atau disebut biodiesel. Berkaitan dengan pengembangan jarak pagar sebagai bahan baku BBN (Bahan Bakar Nabati), maka potensi pemanfaatan hasil ikutan (by-product) pada pengolahan jarak pagar perlu mendapat perhatian karena berpotensi menghasilkan produk-produk yang bermanfaat bagi manusia. Kulit buah jarak pagar merupakan salah satu hasil ikutan (by-product) pada pengolahan jarak pagar yang tidak dimanfaatkan lagi dalam proses pengolahan minyak, sehingga perlu diolah lebih lanjut menjadi produk yang memiliki nilai guna. Kulit buah jarak pagar (Jatropha curcas Linn) merupakan salah satu bahan berlignoselulosa yang memiliki potensi sebagai bahan baku papan partikel. Penelitian ini bertujuan untuk mengetahui sifat fisis dan mekanis papan partikel kulit buah jarak pagar dan pengaruh perlakuan variasi kadar perekat terhadap kualitas papan partikel. Bahan yang digunakan adalah kulit buah jarak pagar, adapun jenis perekat yang digunakan adalah perekat phenol formaldehida (12%, 14% dan 16%) dengan kerapatan target adalah 0,7 g/cm3. Pada penelitian pendahuluan perekat yang digunakan adalah perekat urea formaldehida (10%, 12% dan 14%) dan Standar pengujian yang digunakan adalah standar JIS A 5908 (2003). Hasil penelitian menunjukkan bahwa papan partikel yang menggunakan perekat phenol formaldehida mampu meningkatkan kestabilan dimensi dan sifat mekanis papan apabila dibandingkan dengan papan partikel yang menggunakan perekat urea formaldehida. Berdasarkan hasil pengujian secara keseluruhan, maka sifat fisis dan mekanis papan partikel kulit buah jarak pagar belum sesuai dalam pemanfaatannya sebagai bahan baku konstruksi. Sehingga masih perlu dilakukan upaya peningkatan sifat-sifat papan partikel tersebut. Semakin tinggi kadar perekat yang ditambahkan pada papan partikel maka sifat mekanis yaitu kekuatan lentur, keteguhan patah, keteguhan rekat dan kuat pegang sekrup akan semakin meningkat, sedangkan untuk sifat fisis kadar air, daya serap air dan pengembangan tebal cenderung menurun.
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Judul: Pemanfaatan Ampas Biji Jarak Pagar (Jatropha curcas L.) Hasil Samping Pengepresan Minyak Sebagai Bahan Baku Pembuatan Papan Partikel
Abstrak: Jatropha press cake (Jatropha curcas L) has high crude fiber which is potential to be utilized as raw material for particle board production. This study aims to assess the physical and mechanical properties of jatropha press cake particle board and effect of addition of paraffin and sago starch to improve the quality of particle board. The parafin were added at 0, 1, 3%, and the sago starch were at 6, 8, and 10%, respectively. The physical and mechanical properties of particle board product were evaluated. The density of particle board ranged at 0,84 - 0,95 g/cm3, moisture content 4,56 - 6,19%, the thickness-swelling for 2 and 24 hours water soaking were 11,6 7- 20,12% and 16,22-25,70%, respectively. The water absorption of particle board for 2 and 24 hours water soaking were 48,74-62,20% and 63,10-72,75%. The Modulus of Rufture (MoR) and Modulus of Elasticity (MoE) of particleboard were 19,70 - 97,44 kgf/cm2 and 1552,26-7234,66 kgf/cm2. The addition of paraffin and sago starch have positive effect for physical and mechanical properties of particle board. The particle board with addition of 3% paraffin and 10% sago starch achieves to pass of MoR that accordance with JIS A 5908:2003 standard.
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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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