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: Sifat Fisis, Mekanis dan Kualitas Permukaan Papan Serat Bambu Betung (Dendrocalamus asper)
Abstrak: Bambu betung (Dendrocalamus asper) dapat digunakan untuk material papan serat. Penelitian ini bertujuan untuk menganalisis sifat fisis, mekanis dan kualitas permukaan papan serat bambu betung (Dendrocalamus asper) akibat adanya perlakuan alkali NaOH dengan konsentrasi 2% dan 5%. Papan serat dibuat dengan menggunakan perekat urea formaldehida. Analisis sifat fisis dan mekanis mengacu pada standar pengujian JIS A 5905: 2003. Nilai kerapatan papan serat berkisar antara 0,56 g.cm-3 – 0,59 g.cm-3, kadar air berkisar antara 10,20% - 12,92%, pengembangan tebal setelah perendaman 24 jam berkisar antara 17,69% - 16,02%, daya serap air setelah perendaman 24 jam berkisar antara 67,11% - 103,72%, modulus of elasticity berkisar antara 455,32 MPa – 928,83 MPa, modulus of rupture berkisar antara 4,82 MPa – 7,67 MPa, keteguhan rekat berkisar antara 0,08 MPa – 0.12 MPa, kuat pegang skrup berkisar antara 348,93 N – 634,51 N, kekasaran permukaan berkisar antara 4,63 µm – 4,87 µm. Papan serat yang memenuhi JIS A 5905: 2003 tipe 5 untuk kadar air, pengembangan tebal, modulus of rupture dan kuat pegang skrup adalah papan serat dengan perlakuan NaOH 2%. Sedangkan papan serat bambu betung dengan perlakukan NaOH 5%, memenuhi standar JIS A 5905 tahun 2003 tipe 5 hanya dalam hal kadar air dan kuat pegang skrup. Kata kunci: Bambu betung, papan serat, perlakuan alkali, urea formaldehida.
Keyword: alkali treatment, betung bamboo, fiberboard, 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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