Judul: Synthesis of N-alkylchitosan and its potency as paper coating
Abstrak: N-Alkilkitosan merupakan turunan kitosan yang bersifat ampifilik. Rantai samping alkilnya yang hidrofobik akan menurunkan kapasitas penyerapan air dari kitosan yang hidrofilik sehingga turunan ini dapat diaplikasikan sebagai penyalut kertas kedap air pada kertas pembungkus makanan. Pada penelitian ini, N-alkilkitosan disintesis dari kitosan komersial yang memiliki derajat deasetilasi 86%. Dua metode diujikan, yaitu sintesis dalam sistem heterogen dengan kitosan hanya disuspensikan dalam metanol dan sistem homogen dengan kitosan terlebih dulu dilarutkan dalam asam asetat 1%. Spektrum inframerah menunjukkan bahwa metode sintesis dalam sistem homogen berhasil menyintesis N-oktilkitosan, dibuktikan dengan munculnya serapan ulur C−N di 1540 cm-1. Nilai derajat substitusi (DS) N-oktilkitosan sebesar 0.16 berdasarkan analisis spektrum resonans magnet inti proton. Turunan dengan rantai samping alkil yang lebih panjang (N-desil dan N-dodesilkitosan) memiliki nilai DS jauh lebih kecil, yaitu 0.02, agaknya karena halangan sterik yang lebih besar. Oleh karena itu, berdasarkan penelitian ini, N-oktilkitosan paling berpotensi sebagai penyalut kertas kedap air karena memiliki nilai DS tertinggi. Kata kunci: derajat substitusi, kitosan, N-oktilkitosan, penyalut kertas., N-Alkylchitosan is an amphiphilic chitosan’s derivative. Its alkyl side chain is hydrophobic and will reduce the water absorbing capacity of the hydrophilic chitosan. Therefore, it can be applied as water-resist paper coating in food packaging paper. In this study, N-alkylchitosan was synthesized from commercial chitosan which has 86% deacetylation degree. Two synthetic methods were compared, in heterogenous system using suspended chitosan in methanol and homogenous system where chitosan was dissolved chitosan in 1% acetic acid at the first stage. The infrared spectra showed that synthesis in homogenous system successfully synthesized N-octylchitosan. The degree of substitution (DS) value of the N-octylchitosan was 0.16, based on proton nuclear magnetic resonance analysis. Derivatives with longer alkyl side chain (N-decyl and N-dodecylchitosan) exhibited much lower DS, that is 0.02, which is predicted as the effect of increased steric hindrance. Therefore, based on this study, N-octylchitosan is the most potential as a water resist paper coating because it has the highest value of DS. Key words: chitosan, degree of substitution, N-octylchitosan, paper coating.
Keyword: derajat substitusi, kitosan, N-oktilkitosan, penyalut kertas

Judul: Sintesis Gel Kitosan - Hialuronat
Abstrak: As a polycation, chitosan can form macromolecular complexes with polianions such as hyaluronate. However, the film produced are unstable in acidic and basic conditions that modification is needed to improve the rheological properties. Modification was done in this study by adding glutaraldehyde as chitosan crosslinker.The rheological properties measured ware gel strength, break point, rigidity, swelling, and shrinking. The hyaluronate solutions ware made with consentrations of 0; 0.5; and 1.0% in lactic acid 18% (v/v). Chitosan was then added into each solution until its concentration reached 2.0%. Afterwards, glutaraldehyde 1.0; 2.0; and 3.0% (v/v) was added, to form gel. Chitosan used in this reseach had molecular wight of 7.53 × 105 g mol-1 with moisture content of 11.56% and deacetylation of degree 88.48%. Hyaluronate had molecular wight of 6.33 × 105 g mol-1with moisture content of 13.11%. The optimum chitosan-hyaluronate gel was at 2.0% of chitosan, 0.3 % of hyaluronate and 1.4% (v/v) of glutaraldehyde with gel strength, break point, rigidity, swelling, and shrinking 678.4 g cm-2, 1.294 cm, 5.033 g cm-1, 2.634 g, and 0.148 g, respectively.
Keyword: 

Judul: Penggunaan Trie dalam Membangun Frequent ltemset Menggunakan Algoritmc FPGrowth
Abstrak: FP-growth algorithm search for frequent itemset using the FP-tree data structure which is a prefix tree structure based on pattern growth algorithm. Prefix tree in FP-Growth uses the trie structure in the relationship pattern among the items in the database. Trie is a tree structure that uses strings as key, where each descendant represents a character or prefix. To find frequent itemset, FP-growth algorithm build prefix tree recursively. However, recursive function may need longer time than the Iterative (Manolopoulos 2003). Goal of this research is to create alternatives iteratively to the development of frequent iternset using trie on the FP-Growth. Research was conducted on several stages for the development of the frequent itcmset using a trie, stage through pruning and without pruning. In the last stages of testing is done using the input parameters, enter the difference in support, the number of transactions, and the items involved. Testing stage compare the execution time in the computing process through the stage with pruning and without pruning. Thing that affects the execution time is the number of items involved in development process of the frequent itemset. Frequent itemset development with the pruning process will he faster than without pruning, hecause at the time to build a combination of frequent itemset, infrequent items are not in the development process.
Keyword: