Analisis Laju Pencucian Tanah Salin dengan Menggunakan Drainase Bawah Permukaan

Leaching process with subsurface drainage is needed to solve the salinity problem. This research was conducted to determine the leaching rate of saline soil by contaminants flow in the soil experiments, and determine the accuracy of ILRI's formula (1994) that used in the calculation. Data was collected in some experiments, the experimental of soil physical properties, salt contamination, and soil leaching. The experiments showed the different leaching time to reduce concentration to the desired level, 0.07, 0.13, and 0.08 days, respectively for the percolation rate 1035.73, 1614.12, and 1888.52 mm/day. It is influenced by concentration of dissolved salts (Ct), rate of percolation (q), water storage in field capacity (Wfc), and permeability (K). However there is has a differentation between an experiment and calculating result, so for this condition needs a development of formula that issued by ILRI (1994) with adding a correction coefficient for Wfc value, 0.076, 0.078, and 0.042 for experiments 1, 2, and 3, so the calculation results may approach by the real condition

Penentuan Awal dan Durasi Musim Kemarau Menggunakan Fungsi Polynomial dengan Aplikasi Visual Basic For Applications (VBA)

Forecasting the occurrence of the onset of dry season and its length is important in determining the availability of water for irrigation, domestic and industrial uses. The length of dry season is used for reference in calculating water demand. Prediction of drought can be studied based on the rainfall patterns that have occurred. This is possible because there is a tendency that the rain will repeat a certain pattern at a certain time. The purpose of this study was to predict the onset of dry and rainy seasons as well as their length. Determination of the onset of dry season and its length was conducted using polynomial function of the cumulative amount of rain every single day based on the rain data. The research was conducted using rainfall data from Climate Station III in Serang from 1989 to 2010. The sum of daily rainfall could form a polynomial function. If the magnitude of daily rainfall in a certain period of time is less than the slope of the cumulative annual rainfall, then at that time the dry season is occurred. Determination of the dry season peak can be done by finding the maximum (extreme) point from the polynomial function by getting the second derivative which value is close or equal to zero. In average, the dry season occurred in Serang city started on the 132nd until 300th day. Deviation value for the onset of dry and rainy seasons were 23 and 38 days, respectively, with an average of length of 168 days. The average of R2 value for polynomial function was 0.9937

Groundwater Level Control with a Simple Fuzzy Control System

This paper proposes a method for controlling groundwater level in order to maintain a certain desired height by using a simple fuzzy control system. The control signal is determined by evaluating the state of water surface height deviatioh from the desired height on a 4 quadrant phase plane. The control signal is then used to determine the number of drainage or irrigation pumps, which must be operated. Simulation using actual datafrom the jield shows that the proposed method is very effective to maintain the desired height of water surface. This method is very simple, therefore it can be easily implemented using a personal computer or a microcontrol/er, or up-loaded to a P LC (Programmable Logic Controller)

Pemodelan Lahan Basah Potensial Berdasarkan Indeks Topografi di Bretagne, Prancis

Wetlands represent an important natural resource which supports natural biodiversity. In France, in mentioned wetlands, it called potential wetlands, which have potential in its use.Topography and geomorphology play a major role for the development of wetlands and are decisive factors for modeling wetlands extension.The importance of identifying wetlands, can be used as a basis for determining the development priorities that will be based on technical and socioeconomic aspects The objective of this research was to predict the spatial extent of potential wetlands in Brittany, France from a topographic index calibrated on a set of 10 detailed soil maps. In identifying potential wetlands, it based on soil hydromorphwhich conducted by method 4 criteria. The following four stages of analysis were respectively categorized: (a) identification hidromorphy, (b) calculation topographic index, (c) calculation of threshold, (d) validation.A threshold method was conducted between soil maps and topographic index to indicate the similarity condition. We use for threshold and validation a new way using 120 combination of soil maps. The result oftopographic index was 4.7 and it was applied for all Brittany

Analisis Ventilasi Alamiah Pada Greenhouse Tipe Standard Peak Menggunakan Computational Fluid Dynamics

Standard peak greenhouse is an adapted design for the humid tropical regions. Analysis of the greenhouse natural ventilation had been conducted using 3D Computational Fluid Dynamics (CFD). The objective of this research was to investigate the greenhouse natural ventilation performance on zero and low windspeed conditions. Solidworks® CFD software was used in this study. Climate data and greenhouse characteristics were used as inputs for the simulation. The results of CFD simulation were presented in 3D of airflow vectors in x, y, and z directions. Results of this study showed the importance of roof vents and sidewalls openings for efficient thermally driven ventilation

Algoritma Filter Kalman untuk Menghaluskan Data Pengukuran

The objective of this paper is to apply a simple algorithm of Kalman Filter, wich is know as noise data filtering. The computer program was written in Macro Visual Basic in MS Exel. Testings were carried out on available temperature, Water level and force data and then were comared with the mooving average method. The result shows that the algorithm performed better and lesser deviation than the mooving average

Error Analysis on the Estimation of Cumulative Infiltration Soil Using Green and Ampt Model

Green and Ampt infiltration model is still useful for the infiltration process because of a clear physical basis of the model and of the existence of the model parameter values for a wide range of soil. The objective of thise study was to analyze error on the esimation of cumulative infiltration in sooil using Green and Ampt model and to design laboratory experiment in measuring cumulative infiltration. Parameter of the model was determined based on soil physical properties from laboratory experiment. Newton –Raphson method was esed to estimate wetting front during calculation using visual Basic for Application (VBA) in MS Word. The result showed that Dq contributed the highest error in estimation of cumulative infiltration and was followed by K, H0, H1, and t respectively. It also showed that the calculated cumulative infiltration is always lower than both measured cumulative infiltration and volumetric soil water content