Judul: Kinerja Antikorosi Mangan Bis(Dioktilditiofosfat) Dengan Teknik Polarisasi Potensiodinamik
Abstrak: Senyawa kompleks mangan bis(dioktilditiofosfat) atau MDTP8 merupakan senyawa yang berpotensi sebagai antikorosi dan antibakteri. Kinerja MDTP8 sebagai antikorosi yang dikaji dalam penelitian ini diukur menggunakan teknik polarisasi potensiodinamik. Rendemen MDTP8 hasil sintesis yang diperoleh sebesar 91%. Pengukuran menunjukkan bahwa MDTP8 ini memiliki efektivitas inhibisi (EI) korosi yang tinggi, nilai optimum %EI terdapat pada konsentrasi larutan inhibitor 2%, yaitu 71% dengan derajat penutupan permukaannya 0.71. Parameter termodinamika pada keadaan transisi menunjukkan spontanitas reaksi korosi berkurang dengan kehadiran inhibitor yang dicirikan dengan meningkatnya nilai ΔG* dari 85 ke 90 kJ mol-1. Nilai energi aktivasi pada proses korosi logam Cu dengan adanya MDTP8 sebesar 60 kJ mol-1 lebih tinggi dibandingkan tanpa tambahan inhibitor, yaitu 12 kJ mol-1. Hal ini menunjukkan energi aktivasi meningkat setelah penambahan inhibitor karena meningkatnya energi minimum terjadinya korosi.
Keyword: efektivitas inhibisi, energi aktivasi, mangan bis(dioktilditiofosfat), termodinamika

Judul: Kinerja Antikorosi dan Model Isoterm Adsorpsi Mangan Diisoamilditiofosfat dengan Teknik Polarisasi Potensiodinamik.
Abstrak: Mangan diisoamilditiofosfat (MDTPi) merupakan senyawa kompleks yang dapat berfungsi sebagai antikorosi dan antioksidan. Fungsi yang dikaji dalam penelitian ini adalah sebagai antikorosi yang diukur menggunakan teknik polarisasi potensiodinamik. MDTPi dapat disintesis dari isoamil alkohol, P2S5, dan MnCl2. Randemen MDTPi adalah 38%. Efektivitas inhibisi korosi MDTPi optimum pada konsentrasi 1% (b/v) dengan suhu 26 ᵒC adalah 92%. Parameter termodinamika dapat dilihat dari nilai energi bebas Gibbs keadaan transisi (ΔG*) yang menunjukkan spontanitas reaksi korosi berkurang dengan kehadiran inhibitor. Energi aktivasi meningkat setelah penambahan inhibitor karena meningkatnya energi minimum reaksi. Interaksi yang terjadi antara permukaan logam dan molekul inhibitor adalah secara fisisorpsi dengan ΔGads sebesar –33 kJ/mol mengikuti isoterm adsorpsi Langmuir.
Keyword: isoterm adsorpsi, efektivitas inhibisi, energi aktivasi, MDTPi, termodinamika termodinamika

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