Judul: Pemanfaatan Tanin dari Kulit Kayu Acacia Mangium sebagai Pewarna Alami dengan Sifat Antibakteri
Abstrak: Tanin merupakan kelompok senyawa polifenol yang banyak terdapat pada kulit kayu. Hasil ekstraksi dari tanin dapat memberikan warna sehingga dapat dimanfaatkan sebagai pewarna alami. Sebagai agen pewarna alami, tanin memiliki aktivitas antioksidan dan antibakteri. Penelitian ini bertujuan untuk memanfaatkan tanin dari limbah kulit kayu untuk dijadikan pewarna alami dengan sifat antibakterti yang dapat mengurangi dampak buruk dari pewarna sintetis terhadap pencemaran air. Tanin dilarutkan menggunakan air dengan variasi suhu. Beberapa pengujian komponen kimia tanin diantaranya: fenolik dan analisis lanjut fenolik berupa Py-GCMS, antioksidan, dan antibakteri. Ekstraksi tanin diperbanyak pada suhu optimal berdasarkan pertimbangan pengujian. Pengaplikasian tanin ke kain dengan ditambahkan mordan tawas, lalu kain diuji aktivitas antibakteri. Kerusakan struktur bakteri dianalisis di bawah FESEM. Suhu 90 ᵒC merupakan suhu terbaik utnuk melakukan perbanyakan ekstrak tanin. Kain yang sudah diaplikasikan dengan tawas dan tanin menunjukkan aktivitas antibakteri yang kuat dengan diameter (1–2) cm., Tannins are a group of polyphenolic compounds that are widely found in bark. The extraction of tannins can provide color so that it can be used as a natural dye. As a natural coloring agent, tannins have antioxidant and antibacterial activities. This study aims to utilize tannins from bark waste to be used as natural dyes with antibacterial properties that can reduce the adverse effects of synthetic dyes on water pollution. Tannins are dissolved using water with temperature variations. Some tests of tannin chemical components include: phenolic and further analysis of phenolic in the form of Py-GCMS, antioxidant, and antibacterial. Tannin extraction was propagated at the optimal temperature based on testing considerations. Application of tannin to fabric by adding alum mordant, then the fabric was tested for antibacterial activity. Bacterial structure damage was analyzed under FESEM. The temperature of 90 ᵒC was the best temperature to propagate the tannin extract. The fabric applied with alum and tannin showed strong antibacterial activity with a diameter of (1-2) cm.
Keyword: antibakteri, ekstraksi, mordan, tanin

Judul: Karbohidrat Dalam Ekstrak Tanin Kulit Kayu Akasia (Acacia Mangium Willd)
Abstrak: Pemanfaatan tanin sebagai bahan perekat beberapa produk kayu komposit seperti kayu lapis atau papan serat dau papan partikel di Indonesia pada masa mendataug mempunyai peranan penting seimbungan dengan pemanfaatan limbah hutan tanaman industri yang berupa kulit kayu, khususnya kayu akasia. Tanin pada umumnya diekstraksi dari kulit akasia dengan menggunakan pelarut air panas atau larutan basa encer karena cara ini adalah yang termurah. Ekstraksi tanin yang dilakukan pada penelitian ini menggunakan metode multistage dengan pelamt NaOH (0.5, l.0. 2.0, dan 3.0) %(b/v), dan ekstraksi dengan pelarut air dengan cara refluks pada suhu 80°C selama 3 jam. Kedua cara ekstraksi ini selain mengekstrak tanin juga menyebabkan terekstraksinya karbohidrat yang dapat mengakibatkan penurunan daya rekat. Ekstraksi menggunakan NaOH (0.5, l.0, 2.0, dan 3.0) %(b/v), menghasilkan rendemen tanin berturut-turut rata-rata (13.9, 23.9, 45.2. dan 53.3) %. Bilangan Stiasnynya berturut-turut rata-rata (61.1, 75.8, 76.9, dau 68.4) %. Ekstraksi menggunakan pelarut air panas mengbasilkan rendemen tanin rata-rata 15.9% dan bilangan Stiasnynya 10 l.8%.
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Judul: The Construction of Greedy SVP LLL Algorithm
Abstrak: A lattice is a set of all integer linear combination of a set of linearly independent vectors in ℝ𝑛���. The independent vectors are called bases of lattice. Any lattice can be generated from many bases, and these bases have the same cardinality. In the lattice, the most fundamental and renowned problem is the Shortest Vector Problem (SVP). SVP is a tracking problem of the shortest nonzero vector in a lattice with equivalent bases. In two dimensions, SVP problem has resolved exactly by Gauss’ algorithm. When the lattice dimension is higher than two, A.K. Lenstra, H.W. Lenstra and L. Lovasz gave a LLL algorithm to compute approximation of nonzero shortest vector in the lattice. Reduced bases solution obtained from LLL algorithm still be an approximation and has polynomial running time of arbitrary dimension which large enough. In 1994, Schnoor and Euchner modified this LLL algorithm as a new variant which later was named deep insertion LLL algorithm. This algorithm is a modified version of the LLL algorithm to the terms of the exchange step to improve the accuracy of output of LLL reduced bases and applying it to the subset sum problem. The purpose of this research are: (1) Reconstruct the LLL algorithm and deep insertion LLL algorithm using a geometric approach. (2) Construct a greedy SVP LLL algorithm. (3) Implement the three algorithms in a symbolic programming language, and evaluate them experimentally. A bases ℬ=[𝐛���1,𝐛���2,…,𝐛���𝑛���] in ℝ𝑚��� is called reduced LLL with parameter 𝛿��� if satisfies: (a) |𝜇���𝑗���𝑖���|≤12, for every integer 𝑖���,𝑗��� with 1≤𝑖���<𝑗���<𝑛���. (b)𝛿���‖𝜋���𝑗���(𝐛���𝑗���)‖2≤‖𝜋���𝑗���(𝐛���𝑗���+1)‖2, for 𝑗���=1,2,…,𝑛���−1,where 𝛿��� is a reduced parameter of real numbers with 14<𝛿���<1. The first requirement is the reduced basis 𝛿��� must “nearly orthogonal” and in its computation case, this requirement can be reached out by using the Gram-Schmidt’s orthogonalization. While the second requirement is called exchange step, or used to called as Lovasz condition. By using both of these requirements, then they establish the LLL algorithm. Then, Schnoor and Euchner modify the LLL algorithm based on the requirements of the exchange step called the deep insertion LLL algorithm, where the exchange step is based on the comparison of the projected vector in orthogonal complement [𝐛���1,𝐛���2,…,𝐛���𝑘���−1]⊥ after j-th reduction. To construct greedy SVP LLL algorithm, the requirements of the exchange step is based on purely by comparing norm of lattice 𝐛���𝑗��� with norm lattice 𝐛���𝑖��� for 𝑖���=1,2,3…,𝑗���−1. The process of insertion reduced vector after the exchange step also has done greedily. Then, we calculate the number of arithmetic operation in greedy SVP LLL algorithm for further analysis. The result of our exprimentation for three algorithms on the certain matrix size shows that the running time of the three algorithms increases propotional to the size of the matrix. The result also shows that by using 𝛿���=34 for the LLL algorithm and the deep insertion LLL algorithm, and the greedy SVP LLL algorithm which is a new variant made by using no parameter of 𝛿���, outperform of the other of two previous algorithm in terms of speed with the same output.
Keyword: LLL algorithm, LLL deep insertion algorithm, greedy SVP LLL algorithm