Judul: Utilization of Sago Bark into Paper Products
Abstrak: Rumah produksi pati sagu Pak Ropi merupakan rumah produksi skala kecil yang menghasilkan pati sagu. Permasalahan yang diidentifikasi dari rumah produksi sagu tersebut antara lain limbah padat dan limbah cair dari proses produksi belum diolah dan dimanfaatkan secara optimal. Pada penelitian ini limbah yang dimanfaatkan adalah limbah padat berupa kulit batang sagu dari kulit batang sagu baru dan kulit batang sagu lama (dibiarkan selama 4 minggu). Proses diawali dengan delignifikasi menggunakan NaOH dan pemucatan dengan akali H2O2. Ide solusi dari permasalahan tersebut yaitu memanfaatkan limbah kulit batang sagu hasil produksi sagu menjadi produk kertas dan kemudian dilakukan uji fisis untuk mengetahui kualitas kertas yang dihasilkan. Kertas yang dihasilkan memiliki karakteristik yang unik dan menarik yang dapat dimanfaatkan sebagai kertas seni. Dengan massa yang digunakan 35 g dihasilkan dimensi kertas 14 x 7 cm2 dengan gramatur kertas 90-120 g/m2, densitas kertas 0.12-0.16 g/cm3, ketebalan kertas 0.60-0.70 mm, ketahanan tarik 0.127-0.279 kgf/mm2, serta ketahanan sobek 0.09-0.35 Nm2/kg. Penyimpanan kulit batang sagu selama 4 minggu menghasilkan kertas kulit batang sagu yang telah terjadi delignifikasi secara spontan. Hal ini memperbaiki karakteristik kertas yang dihasilkan. Kata kunci: Delignifikasi, kertas, kulit batang sagu, limbah, Pak Ropi's sago starch production house is a small-scale production house that produces sago starch. Problems identified from the sago production house include solid waste and liquid waste from the production process that have not been processed and utilized optimally. This study, the waste is used solid waste in the form of sago bark from new sago bark and old sago bark (left for 4 weeks). The process begins with delignification using NaOH and bleaching with alkaline H2O2. The idea for the solution to this problem is to utilize waste sago bark from sago production into paper products and then do a physical test to determine the quality of the paper produced. The resulting paper has unique and interesting characteristics that can be used as art paper. With the mass use of 35 g, paper dimensions of 14 x7 cm2 were produced with paper grammage of 90-120 g/m2, paper density 0.12-0.16 g/cm3, paper thickness 0.60-0.70 mm, tensile resistance 0.127-0.279 kgf/mm2, and resistance tear 0.09-0.35 Nm2/kg. Storage of sago bark for 4 weeks resulted in sago bark paper which had been spontaneously delignified. This improves the characteristics of the resulting paper. Keywords: Delignification, paper, sago bark, waste
Keyword: Delignification, paper, sago bark, waste

Judul: Manufacture and Characterization of Nonwood Paper from Dry Sugarcane Leaves and Rice Straw Waste as Paper Bags
Abstrak: Bahan nonkayu menjadi alternatif untuk mengatasi kebergantungan akan kayu dalam industri kertas. Daun kering tebu dan jerami padi merupakan dua contoh limbah pertanian pascapanen yang belum banyak dimanfaatkan. Penelitian ini bertujuan membuat kertas yang dapat digunakan sebagai kantong kertas dengan memanfaatkan limbah daun kering tebu dan jerami padi. Daun kering tebu dan jerami padi dicampurkan dalam tiga perlakuan (%b/b), T1 (50:50), T2 (75:25), dan T3 (25:75). Pulp dibuat secara kimiawi menggunakan NaOH 10% pada suhu ±100 °C selama 120 menit. Pulp lalu dicampurkan dengan perekat PVAc 5% sebelum dicetak menjadi lembaran berukuran A4. Hasil uji ANOVA menunjukkan pengaruh yang nyata (P<0,05) antara perbedaan nisbah bahan baku dengan nilai gramatur, ketahanan tarik, dan ketahanan sobek kertas. Perlakuan T3 menghasilkan kertas terbaik, memenuhi standar mutu kertas, dan dapat digunakan sebagai kantong kertas., Nonwood materials are an alternative to overcome dependence on wood in the paper industry. Dried leaves of sugarcane and rice straw are two examples of postharvest agricultural waste that has not been widely utilized. This research aims to prepare a paper that can be used as paper bags by utilizing dry leaf waste of sugarcane and rice straw. Dried leaves of sugarcane and rice straw were mixed in three treatments (%w/w), T1 (50:50), T2 (75:25), and T3 (25:75). The pulp was chemically prepared using 10% NaOH at ±100°C for 120 min. The pulp was mixed with 5% PVAc adhesive before molding into A4-sized sheets. The ANOVA test results showed a significant effect (P<0.05) between the various ratios of raw materials to grammage, tensile strength, and tear resistance of the paper. T3 treatment produced the best paper, complies with paper quality standards, and can be used as paper bags.
Keyword: agricultural waste, dry sugarcane leaves, paper, paper bags, rice straw

Judul: Penentuan Nilai Eigen dan Vektor Eigen dari Matriks Tridiagonal 2-Toeplitz dengan Pendekatan Polinomial Chebyshev
Abstrak: The eigenvalues and eigenvectors of a matrix can be determined by finding its characteristic polynomials. The characteristic polynomials of a tridiagonal 2-Toeplitz matrix is shown to be closely connected to polynomials which satisfy the Chebyshev recurrence relationship. If the order of the matrix is odd, then the eigenvalues are found explicitly in terms of the Chebyshev zeros and the eigenvectors are found in terms of the polynomials satisfying the recurrence relationship. For even ordered matrices, the situation is more complicated. The problem in these cases is that although the Chebyshev recurrence formula is still applied, its initial values are not generating Chebyshev polynomials
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