Judul: Characteristics of Particle Board from Oil Palm Fronds and Water Soluble Chitosan Adhesive using Three-step Press Method
Abstrak: Mengurangi ketergantungan akan kayu dan emisi formaldehida yang berbahaya menjadi alasan utama dilakukannya studi papan partikel berperekat organik. Pelepah sawit dan kitosan larut air telah diketahui dapat dimanfaatkan sebagai bahan baku papan partikel yang ramah lingkungan. Tujuan penelitian ini adalah menganalisis pengaruh metode kempa three-step press terhadap sifat fisis, mekanis, dan akustik dari papan partikel pelepah sawit berperekat kitosan larut air. Papan partikel disintesis pada variasi suhu 180 oC dan 200 oC. Total waktu pengempaan selama 15 menit dengan breathing stage diletakkan di menit 5 dan menit 10 untuk perlakuan three-step press. Hasil penelitian menunjukkan peletakan fase breathing stage yang semakin mendekati akhir dari total waktu pengempaan meningkatkan sifat fisis dan mekanis papan. Berdasarkan hasil penelitian ini dan merujuk penelitian terdahulu, ada faktor jenis perekat yang berpengaruh pada efektifitas metode three-step press. Secara keseluruhan, variasi suhu 180 oC menghasilkan sifat papan yang lebih baik daripada suhu 200 oC. Pengujian sifat akustik menunjukkan papan yang dikempa dengan metode three-step press termasuk kedalam kategori penyerap suara kelas C menurut standar ISO 11654:1997 dengan nilai NRC sebesar 0,60., Reducing both dependence on wood and harmful formaldehyde emissions are the main reasons for the study of green adhesive particleboard. Palm fronds and water-soluble chitosan have been known to be utilized as raw materials for environmentally friendly particleboard. The purpose of this study was to analyze the effect of the three-step press method on the physical, mechanical, and acoustic properties of water-soluble chitosan-adhesive palm frond particleboard. The particleboard was synthesized at temperature variations of 180 oC and 200 oC. The total pressing time was 15 minutes with the breathing stage placed at 5 minutes and 10 minutes for the three-step press treatment. The results showed that placing the breathing stage closer to the end of the total pressing time improved the physical and mechanical properties of the board. Based on the results of this study and referring to previous research, there is a factor of adhesive type that affects the effectiveness of the three-step press method. Overall, the 180 oC temperature variation produced better board properties than the 200 oC temperature. Tests of acoustic properties show that the board forged with the three-step press method is included in the class C sound-absorbing category according to ISO 11654: 1997 standard with an NRC value of 0.60.
Keyword: Papan Partikel, Sifat Akustik, Kitosan larut air, Pelepah sawit, three-step press, acoustical properties, oil palm fronds, particleboard, water-soluble chitosan

Judul: Papan Partikel Dari Pelepah Kelapa Sawit Menggunakan Perekat Asam Sitrat dan Molase
Abstrak: Pelepah kelapa sawit merupakan biomassa kelapa sawit yang biasanya tidak dimanfaatkan secara optimal, pelepah kelapa sawit memiliki kandungan lignoselulosa yang berpotensi untuk dijadikan papan partikel dan ketersediannya yang cukup melimpah.Penelitian ini bertujuan menghasilkan papan partikel yang ramah lingkungan tanpa menggunakan bahan kimia berbahaya. Selain itu, menganalisis pengaruh kadar perekat dengan menggunakan asam sitrat dan molase terhadap karakteristik sifat fisis dan mekanis papan partikel. Papan dibuat dengan kerapatan target 0,8 g/cm³ dan ukuran 30 x 30x 0,6 cm menggunakan kempa panas suhu 200°C selama 10 menit dengan tekanan 5 Mpa. Pengujian sifat fisis dan mekanis papan partikel mengacu pada standar SNI 03-2105-2006 (kerapatan, kadar air, daya serap air, pengembangan tebal, MOE, MOR, dan keteguhan rekat). Hasil penelitian ini menunjukan kadar perekat berpengaruh nyata terhadap karakteristik sifat fisis dan mekanis papan partikel Semakin tinggi kadar perekat yang ditambahkan mampu meningkatkan sifat fisis dan mekanis pada papan plafon yang dibuat., Palm fronds are palm biomass that is usually not used optimally, palm fronds have lignocellulose content that has the potential to be used as a particleboard and its availability is quite abundant. This study aims to produce environmentally friendly particle boards without the use of harmful chemicals. In addition, it analyzes the effect of adhesive levels using citric acid and molasses on the characteristics of the physical and mechanical properties of particle boards. The board was made with a target density of 0,8 g/cm³ and a size of 30 x 30x 0,6 cm using a heat felt of 200°C for 10 minutes with a pressure of 5 Mpa. Testing of the physical and mechanical properties of particle boards refers to the standard SNI 03-2105-2006 (density, moisture content, water absorption, thickness swelling, MOE, MOR, and internal bounding). The results of this research show that the adhesive content has a significant effect on the characteristics of the physical and mechanical properties of composite ceiling boards. The higher the adhesive content added is able to improve the physical and mechanical properties of the ceiling board made.
Keyword: adhesive content, citric acid, molasses, palm fronds, particle board

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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