Judul: Pemanfaatan Kiambang (Salvinia molesta) dalam Mereduksi Bahan Pencemar pada Limbah Cair Tapioka.
Abstrak: Tapioca wastewater may cause unbalance aquatic ecosystem. It contains cyanide, high organic matter, and acid water. Free floating aquatic plants such as kiambang (Salvinia molesta) can be applied as biological treatment for tapioka wastewater. Kiambang can utilize organic matter from water and from sediment. Therefore, water height could affect utilization of organic matter by kiambang. This research aimed to study the utilization of kiambang to reduce contaminant material in tapioca wastewater with different water height. Result showed that treatment with 10 cm water height decreased cyanide concentration and organic matter more than 20 cm. Wastewater treatment of 10 cm without aquatic plants decreased cyanide and organic matter the most, i.e 70% and 50%, respectively. This was because oxygen diffusion from atmosphere into water was blocked by the plant, causing organic material reduction was blocked as well. Aquatic plants acclimatization in wastewater should be done in a particular time span, so that aquatic plants ability to reduce cyanide and organic matter could be more visible.
Keyword: water height, tapioca wastewater, Salvinia molesta, kiambang

Judul: Kajian Pemanfaatan Tanaman Eceng Gondok (Eichornia crassipes (Mart) Solms) dan Kiambang (Salvinia molesta) Untuk Menurunkan Kadar Nutrien Pada Limbah Cair Tahu.
Abstrak: Tofu industry is producing waste water in large volume and being disposed to natural water. Biological treatment using aquatic plants can be used to remove tofu waste water. Aquatic plants such as Water Hyacinth and Kariba-Weed have rapid growth and resistance to any critical condition. The objective of this research was to determine effectiveness of nutrients removal by Water Hyacinth (Eichornia crassipes (Mart) Solms) and Kariba-Weed (Salvinia molesta) and as a result the effluent of tofu industrial waste water can be disposed safety to the environment. Experiment was divided into two stages. In the beginning of experiment, Water Hyacinth and Kariba-Weed were cultivated with several dilutions. There were 1:0, 1:1, 1:2, 1:3, 1:4, 1:5, and 1:6 in every pond. The best result covered visual research and DO (Dissolve Oxygen) will be used for the main experiment where their nutrient will be analyzed. The nutrients cover total nitrogen, phosphate, nitrate, ammonia, TSS (Total Suspended Solid), COD (Chemical Oxygen Demand), and pH. The result showed that Water Hyacinth with dilution 1:2 has the highest ammonia (NH3) removal that was from 10,4 mg/l becomes 1,45 mg/l with the percentage was amount of 38,52%. Reducing nitrate (NO3) was from 0,339 mg/l becomes 0,178 mg/l with the percentage was amount of 37,19 %, total nitrogen was from 24,6 mg/l becomes 9,8 mg/l with the percentage was amount of 35,58 %, and phosphate (PO4 3-) was from 0,259 mg/l becomes 0,015 mg/l with the percentage was amount of 78,11%. In Kariba-Weed with the dilution 1:2 has removed total nitrogen from 24,6 mg/l becomes 12,55 mg/l and percentage 23,10 %, ammonia removal was from 10,4 mg/l becomes 2,4 mg/l and percentage 31,68 %, nitrate removal was from 0,339 mg/l becomes 0,191 mg/l and percentage 36,29 %, also the phosphate removal was from 0,259 mg/l becomes 0,026 mg/l and the percentage 76,38 %. The effectiveness of nutrient absorption happens until the twelfth day, after it the effectiveness of nutrient is not significant anymore. Along with the amount of nutrient removal by Water Hyacinth and Kariba-Weed, it also happens to TSS and COD removal while the increasing of DO value and pH also happens. The highest TSS and COD removal received by Water Hyacinth with dilution 1:2 which removed TSS from 37 mg/l becomes 10,5 mg/l and removed COD from 670 mg/l becomes 96,52 mg/l. The highest increasing of pH value received by Kariba-Weed with dilution 1:2 which increased pH from 6 becomes 9,3 while Water Hyacinth increased DO from 0,505 mg/l becomes 0,471 mg/l. Designing of tofu processing waste water with the combination of Water Hyacinth and Kariba-Weed in laboratory plant removed high nutrient contents with 8 day of hydraulic retention time. Industrial plant design with 8 day of hydraulic retention time used anaerobic digester and Water Hyacinth and Kariba-Weed pond with 18,3 m x 3,7 m x 0,6 m of dimension to accommodate the amount of waste water as much as 5000 liters. Anaerobic digester was designed with 5 m3 holding capacity of tofu waste water, 0,75 m of digester radius, and 2,8 m of height. After treatments, the
Keyword: 

Judul: Determinan dan Invers Matriks Leslie Ganda dengan Formula Schur
Abstrak: Matriks Leslie ganda merupakan bentuk umum dari matriks Leslie, matriks companion, dan matriks companion ganda. Bentuk khusus komplemen Schur dapat digunakan pada formula Schur untuk mendapatkan rumus determinan dan invers. Tujuan dari penulisan karya ilmiah ini adalah mengkaji secara teoritis pembuktian formulasi determinan dan invers matriks Leslie ganda berdasarkan formula Schur. Pembuktian formula determinan dan invers matriks Leslie ganda dilakukan dengan mensubstitusi formula determinan dan invers matriks persegi menggunakan komplemen Schur., The doubly Leslie matrix is generalized of the Leslie matrix, the double companion matrix, and the companion matrix. The unique form of Schur complement can be used in Schur’s formula to obtain a formula of the determinant and inverse of doubly Leslie matrix. In this article, the proof of those formulation are discussed theoretically based on Schur’s formula. Proof of the determinant and inverse formulation perform by substitute the determinant and inverse of square matrix with Schur Complement.
Keyword: Komplemen Schur, Formula Schur, Determinan, Invers, Matriks Leslie Ganda