Judul: Pengaruh Penggunaan Adsorben  Dan Penggunaan Ulang Adsorben Hasil  Recycling Pada Proses Pemurnian Biodiesel  Minyak Jarak Pagar (Jatropha Curcas L.)
Abstrak: Biodiesel is an alkyl esther which potentially as renewable alternative energy. It could be produced from plant oil derivates such as jathropa pagar oil. Jathropha biodiesel is produced by estrans (esterification-transesterification) reaction. But, in the end of its making, there would be produced dirty biodiesel and another contaminants such as; residue of glycerol, non-reacted methanol, KOH residue and soap produced from the reaction between alkali and free fatty acid during the transesterification. That contaminant will impact the quality of its fuel and has been loosen from the product. Because of that, biodiesel has to be purified in order to have standardized quality that approximately with SNI 04- 7182-2006. The biodiesel purification is commonly used water (water washing method), but this washing method is still having so many weakness that in this research was done the biodiesel purification using adsorbent (dry washing method). This research was aimed to know the impact of adsorbent using and regenerated adsorbent reusing in jathropa biodiesel purification. This research is divided into two stage; introduction and main research. The introduction research was done to know the best adsorbent formulation between silica alumina and silica magnesium. The adsorbent formulation decision was done by some biodiesel characteristic analysis such as acid value, catalyst percentage, soap percentage, free glycerol, total glycerol and bounded glycerol. The experimental designed used in this stage was completely randomized design with one factor, that is adsorbent formulation (Z). The factor (Z) consisted of 8 treatment level, include silica alumina 100%, silica magnesium 100%, and the combination of those two with various comparation; that was 1:1, 1:2, 1:3, 2:3, 2:1, 3:1, and 3:2. In the main research, variety and adsorbent comparation that chose in the former research used for several times and looked the impact of quality characteristic of biodiesel. Before reused, the chosen adsorbent regenerated with water in the temperature of 65-70oC and recovery methanol. The characteristic biodiesel parameter that tested includes acid value, soap value, free glycerol, total glycerol and bounded glycerol. The process of adsorbent activation in biodiesel was significantly reduced the impurities of biodiesel. Based on previous research, best performance was the variety and comparation of 100% silica alumina. The characteristic of purified biodiesel which has been purified by the 100% silica alumina was having the acid value 0.4373 mg KOH/g biodiesel, undetected catalyst, soap contain 53,37 ppm, free glycerol 0,0054%, bounded glycerol 0.2490%, total glycerol 0.2544% and water contain. The result of the main research showed that silica alumina could be used for several times but there was reduction to the quality of the biodiesel. The reduction of biodiesel was significant until the third reuse but it still accomplish the SNI standards. The regeneration process of silica alumina with water 65-70oC produced better methanol compared with recovery methanol. The characteristic of purified biodiesel using first regenerated silica alumina with water in the temperature of 65-70oC was acid value 0.4211 mg KOH/ g biodiesel, undetected catalyst contain, soap contain 1034.5 ppm, free glycerol 0,0079%, bounded glycerol 0.0842%, and total glycerol 0.0921%. The characteristic of the biodiesel in second stage was having the acid
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Judul: Studi Pengaruh Ukuran Pori Filter terhadap Kualitas Biodiesel Jarak Pagar (Jatropha curcas Linn.) yang Dimurnikan Menggunakan Adsorben.
Abstrak: Biodiesel is one of infamous renewable fuel nowadays. Biodiesel is produced from vegetable oils and animal fats. For further usage, biodiesel needs to be purified. The purification method that usually practiced is commonly waterwashing based purification or ‘wet washing’. This method has several weakness and is considered inefficient for removing impurities from biodiesel. The effluent from washing process also cause problems for environmental issues. The actual method which is developed for substituting the waterwashing method is adsorbent-based purification or commonly called ‘dry washing’ method. This method uses adsorbent for removing impurities from biodiesel, which is considered more efficient and less investment than wet ashing method. Filtration becomes one of choices for separating mixture of pure biodiesel and adsorbent. For efficiently separating the mixture, pore size of filter media has to be determined. This research is conducted to determine the best and most efficient filter for filtration purpose, based on the characteristics of both jatropha biodiesel and adsorbent. This research is divided into three steps, which are base material preparation, preliminary research, and main research. At base material preparation, manufacturing of crude jatropha biodiesel and activation of hydrate aluminium silicate and hydrate magnesium silicate as adsorbent are conducted. Preliminary research is conducted to determine the types and comparison between hydrate aluminium silicate and hydrate magnesium silicate as adsorbent. Determination of types and comparison of these adsorbents are conducted using biodiesel characteristics analysis such as acid value, catalys value, soap value, free gyserol value, bound glyserol value, and total glyserol value. Analysis of variance which is used in this step is one-way-ANOVA with one factor, which is the type and composition ratio of the adsorbent (Z). The Z factor is consisted of 11 degrees, i.e. crude biodiesel (without adsorbent), waterwasehd biodiesel (using warm water as purifier replacing adsorbent), and biodiesel which is purified using adsorbent namely hydrate aluminium sylicate 100%, hydrate magnesium silicate 100% and the combination between these two with various ratio: 1:1, 1:2, 1:3, 2:3, 2:1, 3:1, and 3:2. Adsorbent activation process is significant to reduce impurities within biodiesel. According to preliminary research, the best result is obtained when using hydrate aluminium silicate 100%. The characteristics of biodiesel that has been purified using hydrate aluminium silicate 100% are listed such: acid value 0.4373 mg KOH/g biodiesel, undetected catalyst value, soap concentration 53.37 ppm, free-glycerol value 0.0054 %-w, bound-glycerol value 0.2490 %-w, totalglycerol value 0.2490 %-w, dan water and sediment concentration 0.01 %. In main research, the adsorbent used is hydrate aluminium silicate 100% with the concentrate ratio 1.8% from total mass of biodiesel used. The filters which are used have varied pore sizes, range from 2.5, 8, and 20 μm. Filtration that is conducted include one-phase filtration with only one kind of filter used, and multiple-phases of filtration with 2 or 3 layers of filters used. Biodiesel characteristics’ analysis which is conducted include physical analysis, i.e. filtrate yields, transmission-percentage value, and water and sediment concentration. Variety test used for this stage is a one-way ANOVA with one factor, which is type and size of filters with 7 degrees, i.e. single-layer filter vary
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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