Judul: Physical, Mechanical, and Surface Quality of Oriented Flattened Bamboo Boards made from  Betung Bamboo (Dendrocalamus asper) with Alkali Treatment
Abstrak: Salah satu produk komposit dari bambu adalah papan pelupuh. Tujuan dari penelitian ini adalah untuk menganalisis pengaruh perlakuan alkali (NaOH konsentrasi 2% dan 5%) terhadap sifat fisis, mekanis, dan kualitas permukaan papan pelupuh orientasi dari bambu betung. Tujuan perlakuan alkali adalah untuk mengatasi komponen kimia minor yang ada pada permukaan bambu. Evaluasi karakteristik fisis dilakukan untuk kerapatan, kadar air, pengembangan tebal, daya serap air dan uji siklik. Modulus of Elasticity (MOE), Modulus of Rupture (MOR), keteguhan tekan, dan keteguhan rekat internal (IB) dievaluasi untuk sifat mekanis. Selain itu dilakukan juga pengujian kekasaran permukaan. Hasil penelitian menunjukkan bahwa nilai rata-rata kerapatan, kadar air, pengembangan tebal, dan daya serap air masing-masing berkisar 0,62 – 0,64 g cm-3; 8,94 – 13,53%; 12,21 – 17,94%; dan 71,32 – 83,04%. Nilai MOE, MOR, keteguhan tekan dan IB masing – masing papan pelupuh berkisar antara 1187,03 – 3267,70 MPa; 8,75 – 21,53 MPa; 7,11 – 15,10 MPa; dan 0,06 – 0,28 MPa. Papan dengan perlakuan NaOH memiliki karakteristik sifat fisis mekanis yang lebih rendah dibandingkan dengan papan tanpa perlakuan NaOH (kontrol). Semakin tinggi konsentrasi perlakuan NaOH, semakin rendah sifat fisis dan mekanisnya. Kualitas produk yang kurang baik diduga karena masih adanya kulit bambu pada bahan baku bambu., One of the composite products made from bamboo is the flanttened board. The objective of this research was to analyze the effect of alkali treatment (NaOH concentration 2% and 5%) on the physical, mechanical, and surface quality of the orientated flattened board of betung bamboo. The purpose of alkali treatment is to overcome the minor chemical components present on the bamboo surface. The evaluation of physical characteristics was carried out for density, moisture content, thickness swelling, water absorption and cyclic test. Modulus of Elasticity (MOE), Modulus of Rupture (MOR), compressive strength, and internal bond strength (IB) were evaluated for mechanical properties. In addition, the surface roughness test was carried out. The results showed that the average values of density, moisture content, thickness swelling, and water absorption were in the range of 0,62 – 0,64 g cm-3; 8,94 – 13,53%; 12,21 – 17,94%; 71,32 – 83,04%. Meanwhile, the MOE, MOR, compressive strength and IB ranged from 1187,03 – 3267,70 MPa; 8,75 – 21,53 MPa; 7,11 – 15,10 MPa; dan 0,06 – 0,28 MPa, respectively. The boards with NaOH treatment had lower physical and mechanical characteristics compared to the board without NaOH treatment (control). The higher the concentration of NaOH treatment, the lower the physical and mechanical properties. The poor quality product was presumably the presence of bamboo skinned in the material’s bamboo.
Keyword: alkali treatments, betung bamboo, flanttened board, isocyanate, NaOH

Judul: Physical, Mechanical and Surface Quality Properties of Ater Bamboo Fiberboard (Gigantochloa atter Kurz.)
Abstrak: Penelitian ini bertujuan untuk menganalisis sifat fisis dan mekanis papan serat bambu ater (Gigantochloa atter Kurz.) akibat adanya perlakuan alkali (NaOH) dengan konsentrasi 2% dan 5%. Papan serat dibuat menggunakan perekat urea formaldehide (UF) dengan kadar perekat 10% dan target kerapatan sebesar 0.6 g cm-3. Pengujian dilakukan merujuk pada JIS A 5905 (2003). Berdasarkan hasil pengujian diperoleh nilai rata-rata kerapatan papan serat yaitu sekitar 0,60 sampai 0,62 g cm-3. Nilai rata-rata kadar air sekitar 9,36 sampai 9,58%. Nilai rata-rata pengembangan tebal selama 2 jam dan 24 jam berkisar antara 19,20 sampai 37,89% dan 30,02 sampai 53,80%. Nilai rata-rata daya serap air selama 2 jam dan 24 jam berkisar antara 99,98 sampai 131,77% dan 106,47 sampai 142,29%. Nilai rata-rata Modulus of Elastisity (MOE) berkisar antara 765,19 sampai 1069,54 MPa. Nilai rata-rata Modulus of Rupture (MOR) berkisar antara 6,69 sampai 10,40 MPa. Nilai rata-rata Internal Bond (IB) berkisar antara 0,09 sampai 0,14 MPa. Nilai rata-rata KPS berkisar 909,91 sampai 932,78 N. Nilai rata-rata kekasaran permukaan berkisar antara 3,82 sampai 4,35 µm. Pemberian perlakuan alkali konsentrasi 2% dan 5% dalam pembuatan papan serat bambu ater menurunkan nilai sifat fisis dan mekanis papan serat bambu ater. Hasil penelitian menunjukan nilai sifat fisis dan mekanis yang diperoleh umumnya belum memenuhi standar JIS A 5905 (2003) tipe 15, namun masih memenuhi tipe 5., The purpose of this study is to analyze the physical and mechanical properties of ater bamboo fiberboard (Gigantochloa atter Kurz.) concentrations of 2% and 5%. Fiberboard is made using urea formaldehyde (UF) adhesive with 10% adhesive content and density target was 0.6 g cm-3. The test was carried out referring to JIS A 5905 (2003). Based on the test, the average value of fiberboard density is around 0,60 to 0,62 g cm-3. The average value of water content is around 9,36 to 9,58%. The average value of thickness swelling for 2 hours and 24 hours ranged from 19,20 to 37,89% and 30,02 to 53,80%. The average value of water absorption for 2 hours and 24 hours ranged from 99,98 to 131,77% and 106,47 to 142,29%. The average value of the Modulus of Elasticity (MOE) ranged from 765,19 to 1069,54 MPa. The average value of the Modulus of Rupture (MOR) ranged from 6,69 to 10,40 MPa. The average value of Internal Bond (IB) ranges from 0,09 to 0,14 MPa. The average value of the KPS test ranged from 909,91 to 932,78 N. The average surface roughness value ranged from 3,82 to 4,35 µm. Alkali treatment with concentrations of 2% and 5% in the manufacture of ater bamboo fiberboard decreased the value of physical and mechanical properties of bamboo ater board. The results showed that the value of physical and mechanical properties generally did not meet the standards of JIS A 5905 (2003) type 15, but still fullfillment for type 5.
Keyword: bambu ater, papan serat, perlakuan alkali, urea formaldehyde, bamboo ater, fiberboard, alkali treatment, urea formaldehyde

Judul: Pengaruh vaksinasi terhadap dinamika populasi pada model SIR (Susceptible-Infected-Recovered)
Abstrak: SIR model can be used to model the spread of diseases in a closed population based on certain assumptions. In this research, the SIR model is formulated by including the factor of vaccination. As the result, the model has been shown to have two equilibrium points, i.e. disease free and endemic equilibrium. A simulation study is carried out to illustrate the model. The results show that some equilibrium points are asymptotically stable. Moreover, a minimum level of vaccination has been defined. For the vaccination level less than the minimum level, increase in the vaccination level results in decrease of the proportion of infected individuals in the corresponding equilibrium point. On the other hand, for the vaccination level greater than the minimum level, increase in the vaccination level results in decrease the proportion of susceptible individuals in the corresponding equilibrium point. Furthermore, when vaccination level is greater than the minimum level, it is found that the time needed for the disease to extinct is shorter.
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