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: Konversi sampah organik pasar dengan sistem fermentasi media padat menjadi biogas dan pupuk organik.
Abstrak: In 2010 Indonesia produced 200 thousand tons of waste everyday. It causes problems for the society and for environment. The purposes of this research are to design and get an optimal process condition for solid medium fermentation to convert organic waste from traditional market into bioenergy and organic fertilizer, to characterize biogas, digestate, and leachate. The experiments were conducted with 1.5 L and 10 L reactors . Composition of organic waste from traditonal market that gave higest volume of biogas are banana leaf 7.5%, cornhusk 24.2%, bitter melon 14.8%, cabbage 19.9%, chicory 6.2%, water spinach 8.0%, mustard 8.0%, carrots 11.5% (w/w). It produced 4500 ml biogas/kg biomass and the maximum production was reached within 17 days. This equal to biogas production of 37.63 ml biogas/gram VS. Fermentation process in 10 liter reactor with adition of 75% feed, 50% of feed, and 100% feed produced 12378 ml, 10908 ml, and 16707 ml biogas, respectively leachate consists nitrogen 473-4500 ppm, phosphat 47-150 ppm, and COD 8333-12500 mg/l, while the digestate consists of carbon 28-49%, nitrogen 0.7-1.7%, phosphat 0.2-0.4%, and COD 16000-18000 mg/kg. Concentration of methane in biogas is still low and hence futher experiments needed to increase methane concentration. Keywords : organic waste, biogas, digestate, leachate, solid state fermentation
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Judul: Aproksimasi Fungsi Sinus dan Kosinus sebagai Kombinasi Linear dari Fungsi Eksponensial
Abstrak: Salah satu gagasan yang menarik dalam matematika adalah aproksimasi suatu fungsi oleh fungsi lain. Sebagai contoh, fungsi polinom dapat diaproksimasi menggunakan deret Taylor atau fungsi persamaan diferensial dapat diaproksimasi menggunakan deret Fourier. Adapun fungsi yang dapat mengaproksimasi fungsi lain salah satunya adalah fungsi eksponensial. Kemungkinan mengaproksimasi fungsi dengan kombinasi linear dari fungsi eksponensial dari bentuk eˣ, e²ˣ, ... dianggap sebagai perkembangan sejajar dengan gagasan Deret Taylor yang mengaproksimasi fungsi dengan kombinasi linear dari segi fungsi kuadrat. Fungsi sin x dan cos x digunakan sebagai target untuk menilai seberapa baik aproksimasi yang dilakukan oleh fungsi yang diberikan. Aproksimasi fungsi sinus dan kosinus menggunakan hampiran Taylor lebih akurat dibandingkan dengan aproksimasi menggunakan fungsi eksponensial.
Keyword: Aprosimaksi eksponensial, aproksimasi fungsi, aprosimaksi Taylor, fungsi eksponensial