Judul: The Effect of Using Zeolite as Catalyst in Esterification process of Jatropha Curcas Oil to Yield and Biodiesel Qualities
Abstrak: This research is divided in three steps: raw material preparation, introductary research and main research. In the first step, the process of activation is done in natural zeolite by using heating method and degumming process to Jatropha curcas oil with heating and acidic method. The purpose of introductary research is to find type and concentration of zeolite which gives the best result in esterification process. In this step the randomize complete factorial experiment with two factor is used as experimental design th etype of zeolite (Z) as the first factor and the concentration of zeolite (A) as the second one. The Z factor consist of two level natural zeolite and activated zeolite, whereas factor A consist of three level: 1%, 2% and 3%(b/b) to oil. In the main research, zeolite as a catalyst in esterification process is used for several times and the effects of reusing it was evaluated to yield and biodeisesl qualities. Every reused, zeolite firstly washed with water and alkohol. Biodiesel qualities is decided by yield measurement and analyzing the acid number, saponification number, esters number, visitory and density.
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Judul: Desain Esterifikasi menggunakan Katalis Zeolit pada Proses Pembuatan Biodiesel dari Crude Palm Oil (CPO) melalui Metode Dua Tahap Esterifikasi-Transesterifikasi
Abstrak: Oils with high amount of free fatty acid (FFA) such as crude palm oil are becoming one of the promosing alternatives to produce biodiesel;due, principipally, to it low cost. However, because of the presence of FFA, the conventional basic homogenous catalyst should not be the used with the aim to avoid the production of soaps. The use of activated of natural zeolit to perform the esterification reaction into biodiesel is studied in this work. Optimization of reaction condition such as molar ratio of alcohol to oil, reaction temperature and catalyst loading was performed to minimize FFA using response surface methodology (RSM). The RSM suggested that a catalyst of loading 1.59 %; molar ratio of alcohol to oil 23.41:1 and time of reaction 170 minutes were optimum for minimizing FFA. The esterification of FFA using this heterogeneous catalyst appears as a great alternative to esterify oils with high amount of FFA; in this case, the final conversion of FFA achieved was around 64.23 %.
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Judul: Closed Knight’s Tour pada Papan Catur Berbentuk Persegi Panjang dengan Ukuran Maksimal 8 × 8
Abstrak: Closed Knight’s Tour merupakan langkah kuda yang mengunjungi setiap kotak pada papan catur tepat satu kali dengan langkah kuda berawal dan berakhir pada kotak yang sama. Graf yang terbentuk dari closed knight’s tour dinotasikan sebagai graf G(m,n), dengan m adalah banyaknya baris dan n adalah banyaknya kolom. Graf tersebut memuat Hamiltonian cycle. Sebuah graf terhubung G adalah graf bipartite jika dan hanya jika graf tersebut tidak memiliki cycle dengan panjang ganjil. Papan catur yang memenuhi syarat cukup untuk memiliki closed knight’s tour adalah papan catur berukuran 5 × 6, 5 × 8, 6 × 6, 6 × 7, 6 × 8, 7 × 8, dan 8 × 8.
Keyword: bipartite, closed knight’s tour, hamiltonian cycle, knight’s tour, teori graf