Judul: Kualitas air pada pemeliharaan ikan nila Oreochromis sp intensif di kolam Departemen Budidaya Perairan Institut Pertanian Bogor
Abstrak: Tilapia Oreochromis sp. is one of the most importants freshwater fish that have a high potential of economic value to be an intensive culture. Water quality management is the major component that must be considered in increasing production. The application of a paddle wheel on aquaculture is used in order to be able to maintain the supply of oxygen, which required for the growth of fish. This study aimed to analyze the effect of water quality parameters on decreased in appetite and body resistance in an intensive culture of tilapia. The study was conducted by taking samples of water at depth ranged from 10 to 30 cm with different distances in pond culture. The samples were taken at 06.00 am and at 02.00 pm. Water quality parameters observed in this study were dissolved of oxygen (DO), temperature, pH, ammonia, and organic matter content. The results of study showed that dissolved of oxygen ranged from 5.5 to 7.6 mg/l; water temperatur ranged from 26.9 to 28.3 °C; pH ranged from 6.85 to 7.68; ammonia ranged from 0.0012 to 0.017 mg/l; and the organic matter content ranged from 11.16 to 38.44 mg/l KMnO4. The values of water quality parameters measured in the range of optimal. Decreased appetite in fish caused by the concentration level of ammonia (NH3) that have almost reached its upper limit and the high concentration of the total organic matter in the water, so that fish are more susceptible to disease. The operation of the paddle wheel was supplied enough of oxygen for aquatic organisms, so that the concentration of dissolved oxygen did not reduced.
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Judul: Pertumbuhan ikan nila BEST Oreochromis sp. dalam budidaya sistem akuaponik dengan waktu tinggal aliran air yang berbeda
Abstrak: Intensive culture of BEST tilapia does not only produce fish biomass but also waste. The waste are usually managed to avoid its toxic which can hamper fish growth, and even, cause death of fish. One of the management activity is application aquaponic as a culture system. The purpose of the study was to determine water flow detention time in the hydroponic chamber to achieve optimal growth and production of the fish in the aquaponic culturing system. The water flow treatment consisted of 3 level of detention time, is 30, 60, and 120 minutes. Another treatment was culturing the tilapia in a flow through culturing system as a control. During 40 days culturing periode, the highest daily individual, biomass and length growth rate up to 0.54 g/day, 369.58 g/day and 5.58 cm respectively (P<0.05). While survival rate of the fish was at the range of 64.50-80.80%, feed conversion rate was 1.24-1.33 (P>0.05). The result showed that the detention time affected individual, biomass and length growth rate of the fish, in which the highest value reached by the detention time of 120 minutes. While survival rate and feed conversion rate were not affected by the different detention time treatments. The aquaponic system could remove total N and P up to 10.69 % and 38.10% respectively. The 120 minutes detention time treatment resulted in the highest economic benefit.
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Judul: Invers dari Matriks Tridiagonal Jacobi
Abstrak: Suatu matriks berukuran n×n dinamakan matriks tridiagonal jika untuk . Karya ilmiah ini memberikan algoritma yang mudah untuk menemukan invers ( dari matriks tridiagonal Jacobi yang simetrik dan nonsimetrik. Setiap elemen pada matriks tridiagonal ini adalah bilangan real. Terdapat 3 lema dan 2 teorema untuk menentukan . Lema pertama menunjukkan persamaan utama dalam membuktikan lema-lema dan teorema-teorema selanjutnya. Invers dari matriks yang simetrik dibuktikan oleh lema kedua yang menunjukkan elemen-elemen baris ke- dari . Selanjutnya, lema kedua dilengkapi dengan teorema pertama yang menunjukkan elemen-elemen dengan . Invers dari matriks yang nonsimetrik dibuktikan oleh lema ketiga yang menunjukkan elemen-elemen dengan dan elemen-elemen dengan dibuktikankan oleh teorema kedua.
Keyword: symmetric, nonsymmetric, matrix