Judul: Karakteristik Papan Partikel Fungsional Sabut Kelapa Dengan Penambahan Arang Aktif Sebagai Penjerap Gelombang Elektromagnetik
Abstrak: Particle board is a substitute material that can meet national wood needs. Indonesia, a country with the largest coconut plantations, has abundant coconut coir waste which has not been utilized optimally. As the lignocellulose-containing material, coconut coir can potentially be processed into particle board. Due to technological developments, particle board is not only used for construction but also has additional functions. The objective of the research is to determine the physical and mechanical properties of coconut coir particle board and the effect of adding activated charcoal to partcile board in absorbing electromagnetic wave radiation. Activation of coconut coir-activated charcoal was carried out at a temperature of 750 oC by comparing two activators, namely H3PO4 10% and KOH 10%. The activation process took place for 60, 90 and 120 minutes. The best activated charcoal would be used as a particle board mixture. Particle board was made with three factors, namely particle size, board thickness and amount of adhesive. The particle sizes used were coarse (passed 40 mesh, retain 60 mesh) and fine (passed 60 mesh, retain 80 mesh). The thickness treatment used a thickness of 0.5 and 1 cm while the amount of adhesive used a concentration of 0, 5 and 10%. The board's production used a hot press at a temperature of 170 oC for 20 minutes. Based on physical and mechanical properties testing, the best particle board was produced from the coarse particle size treatment (40 mesh passed, 60 mesh retained), 0.5 cm board thickness and 5% adhesive content. The best activated charcoal was then added to the particle board with the amount of 0, 5, 10, 15 and 20%. Based on the physical and mechanical test results, functional particle board does not meet the standards. However, the addition of 15% activated charcoal to the particle board was able to absorb electromagnetic waves by 74.88%. This best adsorption produces a reflection loss value of -12 dB at a frequency of 10.53 GHz.
Keyword: activated carbon, adsorption, coconut coir, electromagnetic wave, particle board

Judul: Eco-Friendly Particle Board from Coco Fiber with Starch-Based Adhesives
Abstrak: Serat sabut kelapa merupakan serat alami yang memiliki potensi untuk dimanfaatkan sebagai bahan baku pembuatan papan partikel, karena mengandung lignoselulosa dan memiliki sifat ramah lingkungan. Penggunaan perekat maltodekstrin dengan asam sitrat sebagai perekat ramah lingkungan cukup baik dalam mengikat serat kayu sehingga pada penelitian ini mencoba menggunakan maltodekstrin-asam sitrat. Penelitian ini bertujuan untuk mengetahui ukuran partikel yang optimum untuk menghasilkan produk papan partikel. Penelitian ini menggunakan ukuran partikel sebesar 40-50 mesh, 50-60 mesh, dan lolos 60 mesh. Sifat fisis yang diuji dalam penelitian ini antara lain kerapatan, kadar air, daya serap air dan pengembangan tebal. Sifat mekanis yang diuji yaitu Modulus of Elasticity (MOE) dan Modulus of Rupture (MOR). Hasil penelitian menunjukkan ukuran partikel ukuran partikel tidak memberikan pengaruh yang nyata pada kerapatan, kadar air, daya serap air, pengembangan tebal, MOE dan MOR. Nilai sifat fisis yang diuji telah mencapai standar JIS A 5908-2003. Ukuran partikel optimum seratsabut kelapa untuk menghasilkan papan partikel cukup baik yaitu lolos 60 mesh., Coconut fiber is a natural fiber that has the potential to be used as a raw material for making particleboard, because it contains lignocellulose and has environmentally friendly properties. The use of maltodextrin adhesive with citric acid as an environmentally friendly adhesive is quite good in binding woodfibers, so in this study we tried to use maltodextrin-citric acid. This study aims to determine the optimum particle size to produce particleboard products. This study used a particle size of 40-50 mesh, 50-60 mesh, and passed 60 mesh. The physical properties tested in this study include density, moisture content, water absorption and thickness expansion. The mechanical properties tested were the Modulus of Elasticity and the Modulus of Rupture. The results showed that the particle size didn’t have a significant effect on density, moisture content, water absorption, thickness swelling, MOE and MOR. The value of the tested physical properties has reached the JIS A 5908-2003 standard.The optimum particle size of coco fiber to produce particleboard is quite good, which is passed 60 mesh.
Keyword: Coco fiber, Mechanical properties, Particle board, Particle size, Physical properties

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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