Judul: Kandungan nitrogen dan fosfor pupuk organik cair dari sludge instalasi gas bio dengan penambahan tepung tulang ayam dan tepung darah sapi
Abstrak: Composting is not a new thing in the public and so many methods in composting which implemented to support composting technology. Composting is defined as biochemical process to transform organic material to manure by microorganism integrated or separated. Motivated by expanded of rumour continuing farming in safe environment, pollution, and reduction land fertility content consequence of chemical fertilizer, also about the higher of artificial fertilizer price, cause the interest of farmer and society increase to use organic fertilizer as soil nutrition in agriculture development system.
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Judul: Nitrogen Content (N) of liquid Organic Fertilizer from Urine Addition in Liquid Sludge of Bio Gas Digester with Cow Feces as Influent.
Abstrak: Animal processing plant has resulted mainly product like milk, meat and egg. Beside that, animal processing plant was produced waste which could be demage to environment and human life. Dairy processing plant is one of animal processing plant and milk as a main product and faeces, urine and slurry as animal waste. Use of animal waste as influent in bio gas digester to product source of energy (methane) and sludge which of still fertilizer content and need to be continous processing in order to get a good quality of fertilizer content trough out liquid composting wich added dairy cow urine as nitrogen (N) source. This research was held in October 2002 until November 2002 in Kebon Pedes, Tanah Sareal, Bogor City, in Biotrop and in Laboratorium Animal production, in Sub. Lab. Animal Waste Treatment and Animal By-product, Facuity of Animal Science, Bogor Agriculture. This research was used urine 0, 2, 4, 6 litter as a treatment, in 20 littes sludge from bio gas digester and then composted for ten days. The paramter was measured nitrogen (%) and with commposite of carbon (%), phosphor (%), potasium (%), nitrate (ppm), Cation Exchange Capacity (CEC) meq/100g, C/N ratio dan pH at five first days composting. The design analitycal methode in this research was used Randomized Block Design (RBD) and four digesters as group.
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Judul: Pemodelan Nilai Tukar Rupiah terhadap Dollar Amerika Menggunakan Deret Waktu Hidden Markov Empat Waktu Sebelumnya
Abstrak: The exchange rate of Rupiah to US Dollar fluctuates according to time in a long period. An existing exchange rate might happen again in the future. Assume that the causes of the fluctuation are not observed directly and form a Markov chain, then the exchange rate of Rupiah to US Dollar can be modeled by the hidden Markov time series. In this research, the model used to describe the exchange rate of Rupiah to US Dollar is the four previous time in hidden Markov time series. This model assumes that the exchange rate of Rupiah to US Dollar depends on Markov chain explained by the cause of occurence and the four previous exchange rates of Rupiah to US Dollar. The model parameter is estimated by using the maximum likelihood method, while the estimation itself is calculated using the expectation maximization algorithm, which is implemented using Mathematica. After estimating the parameter, the exchange rate of Rupiah to US Dollar are calculated. The results are as follows. The symmetric mean absolute percentage error (SMAPE) is 2,1%, the maximum absolute error is 19,16%, the minimum absolute error is 0,0036%, and only 1,95% of the whole absolute percentage error that is bigger than 10%. These results show that the four previous time in hidden Markov time series can describe the exchange rate of Rupiah to US Dollar very well.
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