Judul: Pengaruh Penambahan TiO2 pada Ciri Zeolit yang Disintesis dari Kaolin Alam.
Abstrak: Penelitian terdahulu menunjukkan bahwa sintesis nanokomposit zeolit/TiO2 secara hidrotermal dengan penambahan TiO2 sebelum kristal zeolit terbentuk, menghasilkan jenis zeolit sintetik yang berbeda-beda. Penelitian ini bertujuan mengamati pengaruh penambahan TiO2 pada ciri zeolit. Bahan dasar sintesis zeolit adalah kaolin alam dari Bangka Belitung. Nanokomposit zeolit/TiO2 disiapkan dengan nisbah metakaolin:TiO2 95:5%, 90:10%, 85:15%, dan 80:20% b/b pada suhu 100 ºC selama 24 jam dengan ragam konsentrasi NaOH 1.5, 2, dan 2.5N. Zeolit dan nanokomposit zeolit/TiO2 yang diperoleh dicirikan menggunakan difraksi sinar-X, spektrometer inframerah transformasi Fourier, dan mikroskop elektron payaran. Sintesis zeolit tanpa tambahan TiO2 menghasilkan zeolit A, sementara tambahan TiO2 menghasilkan zeolit tipe sodalit. Diamati juga bahwa NaOH memengaruhi derajat kristalinitas, dengan konsentrasi NaOH terbaik dalam sintesis zeolit dan nanokomposit zeolit/TiO2 sebesar 2N.
Keyword: hidrotermal, kaolin alam, nanokomposit, TiO2, zeolit

Judul: Sintesis Zeolit X Dan Nanokomposit Zeolit/TiO2 Dari Kaolin Dengan Sekam Padi Sebagai Sumber Silika
Abstrak: Zeolite X was synthesized from kaolin originated from Bangka Belitung and was added with silica from rice husk ash. Zeolite X was synthesized because it has many benefits, including as an adsorbent. Kaolin was used as raw material due to its high content of silica and alumina, which were 48.03% and 35.50% respectively. Meanwhile, silica from rice husk ash was used in the form of sodium silicate. Zeolite was synthesized through hydrothermal process inside a polypropylene bottles, by mixing metakaolin, the calcined form of kaolin heated at 700 °C for 6 hours, with sodium silicate and NaOH to activate the major components of Si and Al in the kaolin. Hydrothermal processes were carried out at 100 °C for 24 hours with NaOH concentrations of 1.5 N and 2.5 N. The concentration of NaOH used was resulted in certain type of zeolite obtained. Zeolite X was obtained when the addition 2.5 N NaOH with NaP1 and Faujasite as impurities. On the other hand, NaOH 1.5 N gave NaP1 zeolite. Modification of zeolite to nanocomposite zeolit/TiO2 was shown to have better capability, that was adsorption-photocatalytic property due to its ability to degrade methylene blue under ultraviolet light.
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Judul: Penyelesaian Stacker Crane Problem dengan Algoritme Largearcs dan Smallarcs
Abstrak: In graph theory, the Rural Postman Problem (RPP) aims to determine the shortest route with minimum cost, in which only certain edges or arcs are necessarily traversed. One type of RPP is Stacker Crane Problem (SCP) which deals with a mixed graph but only arcs are necessarily traversed. SCP can be solved by using two heuristic algorithms, i.e. Largearcs and Smallarcs algorithms, which include other algorithms in their steps, such as: Dijkstra algorithm to determine shortest route, Hungaria method to determine minimum bipartite matching, Prim algorithm to determine minimum spanning tree, and van Aardenne-Ehrenfest & de-Bruijn algorithm and Fleury algorithm to determine Euler circuits. The shortest Euler circuit resulted from two heuristic algorithms can be used to find a solution of SCP. The application of SCP is illustrated in establishing the minimum distance route of catering delivery.
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