Browsing by Author "Savitri, Kesni"

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    Pemodelan Dinamik dan Simulasi Siklus Nitrogen pada Kolam Pembesaran Lele
    (2013-06-24) Savitri, Kesni; Zulfansyah; Asmura Jecky
    Nitrogen is an important element in aquatic environments. Utilization of nitrogen contained in the feed as a source of energy and simultaneously toxic to aquatic systems, especially in catfish ponds. The nitrogen concentration in the form ammonia is toxic to catfish if it higher than lethal dose 0,6 mg N/l, so the nitrogen concentration in the form of ammonia has to be kept at low value, below 0.6 mg N/l. The interactions between various nitrogen are complex and difficult to analysis. However, it can be described by a mathematical model. So the dynamic modeling and simulation aimed to predicting the nitrogen dynamics and study the effect of variations in eviromental management is a % protein in feed, feed rate, and water exchange rate on nitrogen dynamics. In this research variation % protein feed used were 20%,30% and 40%. Variations feed rate based on fish weight were 2,9%, 3,9% and 4,9% and water exchange rate used were 5%, 10% and 15%. The data conditions of catfish pond and initial value of nitrogen concentration were obtained from literature. Nitrogen dynamics model which formed a system of ordinary differential equation 1 was solved by Runge-Kutta order 4 method. Models was implemented using Matlab. The result accumation N-NH3 of All variations of pond management below of N-NH3 toxicity limit for catfish is < 0.6 mg N/l. However, the concentration of N-NH3 should be kept from 0,02 to 0,08 mg N / l. So the recomended management treatment is giving 20% protein, 2,9% feed rate and 15% rate of water exchange.
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    Penyelesaian Numerik Metode Distilasi Biner McCabe-Thiele
    (2013-05-07) Vhiwendro, Guntur; Savitri, Kesni; Satria, Rendy; Rionaldo, Hari; Zulfansyah
    The Graphical McCabe-Thiele is a method to calculate the theoretical stage of biner distillation. Generally, that’s still used to analyze the biner distillation because a simple formulation and mostly used in chemical engineering course. The equilibrium curve, operation line and equilibrium stages are constructed, sothatthe number of theoretical stages can be calculated. Furthermore, drawing an equilibrium curve, operation line, and equilibrium stages must be accurate. It will be complicated to observe the impact of input difference, because the curve should be re-constructed and need more time. This article use matlab for solving the distillation biner’s equation (ethanol and water). The numerical calculation for R = 3 acquired the ideal stage = 11,5313, actual stage = 16,6682 and overall efficiency = 0,6918. Furthermore, the calculation with R = 2 get the ideal stage = 16,7885, actual stage = 24,6271and overall efficiency = 0,6817. Numerical method can solve this problem without change the equilibrium curve, operation line and equilibrium stages.