Judul: Potential of Red Brick as Adsorbent of Methylene  Blue and Dark Blue Wantex
Abstrak: Batu bata merah merupakan salah satu jenis batu bata yang paling banyak digunakan di Indonesia. Proses pembuatannya meliputi persiapan, pengadukan, pencetakan, pengeringan, sisik, dan pembakaran. Batu bata merah di Desa Tegalombo, Kecamatan Dukuhseti, Kabupaten Pati, Provinsi Jawa Tengah terbuat dari campuran tanah liat, sekam padi, serbuk gergajian, dan air. Batu bata merah memiliki pori yang dihasilkan dari bahan pengisinya, yang dapat digunakan sebagai adsorben. Penelitian ini bertujuan membuat adsorben dari campuran adukan batu bata merah dan studi literatur kemampuannya dalam menjerap pewarna metilena biru dan wantex biru tua. Adsorben dibuat dengan metode yang sama dengan proses pembuatan batu bata merah. Penelitian pendahuluan terhadap kemampuan adsorpsi batu bata merah dilakukan dengan menggunakan pewarna metilena biru. Terdapat pengaruh terhadap ukuran adsorben yang digunakan, yakni bubuk batu bata mempunyai kemampuan adsorpsi yang lebih baik dibanding batu bata berukuran kelereng. Variasi komposisi tanah liat 75% dan arang sekam 25% menghasilkan kemampuan adsorpsi terbaik. Batu bata merah berpotensi sebagai adsorben wantex biru tua, namun kemampuan adsorpsinya tidak terlalu efektif bila dibandingkan sebagai adsorben metilena biru.
Keyword: Adsorption, adsorbent bricks, bricks, wantex dye

Judul: Adsorpsi Cibacron Red Menggunakan Campuran Kaolin Ampas Tebu dan Bentonit-Ampas Tebu
Abstrak: The use of agroindustrial waste and clay mineral have been studied as alternative adsorbents for dyes, such as Cibacron Red. Cibacron Red is one of reactive dyes which is widely used in textile industries In this research, the mixture of sugarcane bagasse and kaolinite or bentonite were used as adsorbents for cibacron red. Acid and base treatments were carried out to activate the adsorbents. Adsorption was carried out by varying adsorption times and adsorbent weights. The result showed that acid activated bagasse had the highest adsorption capacity. The optimum adsorption time and adsorbent weight were 120 minutes and 1 g with decrease of concentration from 50 mg/L to 7.99 mg/L. On the other hand, the optimum conditions for commercially activated carbon were 90 minutes and 1 g with decrease of concentration from 50 mg/L to 16.18 mg/L. The adsorption capacity and efficiency for acid activated bagasse was better than the commercially activated carbon. The adsorption capacity for acid activated bagasse and activated carbon were 2.10 mg/g and 1.69 mg/g adsorbent. The adsorption efficiency were 84.00% and 67.64%. Acid activated bagasse were followed Freundlich and Langmuir isotherm type, it was mean that adsorbent type is fisisorption and chemisorption.
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Judul: Analysis of Unequal Income Distribution with Cobb-Douglas Production Function
Abstrak: This paper studies the economic growth model by Moav (2002). Moav model shows the existence of unequal income distribution between low-income with high-income community. That kind of unequal income distribution is caused by uneven distribution of income. On this Moav model, there is one area called the threshold. Threshold becomes a benchmark to determining whether a society is categorized into low- or high- income community. The production function used in this paper is the Cobb-Douglas function. The dynamics of this model is described as difference equation of low-income, threshold, and high-income community. Simulation study on the model is carried out using Maple 13 and Mathematica 7.0 software. Overall, from the observed case, high-income community will reach a stable condition earlier, followed by the threshold, and then the low-income community.
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