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: Studi pengaruh ukuran pori-pori filter terhadap kualitas biodiesel jarak pagar (Jatropha curcas Linn.) yang dimurnikan menggunakan adsorben
Abstrak: Biodiesel merupakan salah satu bahan bakar terbarukan yang marak dibicarakan akhir-akhir ini. Biodiesel dibuat dari bahan-bahan berupa minyak nabati dan lemak hewani. Untuk keperluan penggunaan selanjutnya, biodiesel kasar harus dimurnikan terlebih dahulu. Metode pemurnian yang biasa digunakan adalah metode wet washing atau pencucian biodiesel menggunakan air hangat. Metode ini disinyalir memiliki beberapa kelemahan dan tidak terlalu efisien dalam menghilangkan pengotor dari biodiesel. Limbah hasil cuci biodiesel juga menjadi masalah tersendiri dalam konteks lingkungan. Metode yang akhir-akhir ini dikembangkan sebagai substituen dari metode water washing adalah metode dry washing atau pemurnian dengan adsorben. Metode ini memanfaatkan adsorben sebagai bahan pemurni biodiesel, yang diyakini lebih efisien dan murah dalam penggunaannya. Filtrasi merupakan salah satu cara yang digunakan untuk memisahkan antara biodiesel yang telah murni dan adsorben. Untuk lebih mengefisienkan hasil pemisahan antara biodiesel murni dan adsorbennya, maka ukuran pori dari media filter harus ditentukan. Penelitian ini dikembangkan untuk menentukan ukuran pori filter yang paling efisien dalam proses filtrasi, tergantung dari karakteristik biodiesel jarak pagar dan jenis adsorben yang digunakan. Penelitian ini terbagi menjadi tiga tahapan, yaitu persiapan bahan baku, penelitian pendahuluan dan penelitian utama. Pada tahapan persiapan bahan baku dilakukan proses pembuatan biodiesel kasar jarak pagar dan proses aktivasi hidrat alumunium silikat dan hidrat magnesium silikat sebagai adsorben. Penelitian pendahuluan dilakukan untuk mencari jenis dan perbandingan antara hidrat alumunium silikat dan hidrat magnesium silikat sebagai adsorben. Penentuan jenis dan perbandingan adsorben dilakukan melalui analisis karakteristik biodiesel seperti bilangan asam, kadar katalis, kadar sabun, kadar gliserol bebas, gliserol total dan gliserol terikat.…
Keyword: Biodiesel, Jatropha, Filtration, Filter, Pores

Judul: Grup dan Homomorfisma Grup pada Rubik Revenge
Abstrak: Rubik cube is a kind of puzzle game. A player must arrange rubik sides, which have been disordered, back to the position where every side has the same colour. This paper does not focus on the settlement solution, but instead on proving the existence of a group homomorphism between rubik movement group and S96 symmetric permutation group in rubik revenge. Firstly, it has been proved that rubik movement set is a group. Then, it also has been proved that the M set, which contains numeric labels of 1 until 96 in cubinos sides, is S96 symmetric permutation group.
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