Judul: Penentuan waktu retensi sistem akuaponik untuk mereduksi limbah budidaya ikan nila Oreochromis sp.
Abstrak: The availability of land and water for aquaculture process has become more limited as the population growth and development progress. Technological innovations needed to anticipate the decline of aquaculture production as a result of depreciation of land cultivation and decreased water quality. One of the technological innovations that can be applied to the fish farming integrated with crop through aquaponic system. This study aims to determine the optimal 8 retention time aquaponic system so as to reduce waste and support the productivity of cultured tilapia Oreochromis sp. The research was conducted from June 13th to July 23th 2011, at the Environment of Aquaculture Research Installation and Toxicology, Cibalagung, Bogor. This study using Randomized Complete Design with treatment retention time 30 minutes, 60 minutes, and 120 minutes. Water flowed to the principle of recirculation, so that waste water from fish farming process that goes into the container kale plant maintenance will then be reused as a water source in the process of fish farming. The results showed the determination of retention time aquaponic systems that do not influence significantly different on the 95% confidence interval to survival rate and specific growth rate of tilapia BEST. However, effected to reduction of ammonia, nitrite, and nitrate culture media. The longer retention time will be increase the percentage reduction of ammonia, nitrites, and nitrates, but not inversely proportional to the concentration of ammonia, nitrite, and nitrate in culture media. Retention time 60 minutes show the lowest range concentrations of ammonia, nitrite, and nitrate at 0.029-0.615 ppm, 0.045-0.162 ppm, and 0.227-0.658 ppm.
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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: Metrik Einstein (Anti-) Self-Dual Berdimensi Empat dengan Metode Cartan
Abstrak: Gravitational field equation can be formulated in differential forms (differential geometry), which describes gravity as a manifestation of the curvature of space-time. Curvature of space-time is characterized by a metric that satisfies the gravitational field equation. With differential forms it can be formulated the (anti-) self-dual Einstein equation, which is a modification of the Cartan structure in (anti-) self-dual basis. Calculation of (anti-) self-dual metric with (anti-) self-dual Einstein equation is simpler than the calculation using Christoffel symbols.
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