Judul: Analysis of water balance and aridity index in catchment and irrigation area of Jatiluhur Reservoir
Abstrak: One of the functions of Jatiluhur Reservoir is to supply irrigation water for 264.000 ha of agricultural land in Pantura, West Java. Most of the farmlands in these area had water deficit during dry season. The purpose of this study were to analyze the water balance and aridity index in catchment and irrigation area of Jatiluhur reservoir, to calculate crop water requirements, irrigation water requirements and efficiency of irrigation channels on farms in the region Pantura West Java, and also to identify and mapping the areas that should receive high priority irrigation water supply. Water balance analysis using Thornthwaite- Mather method was done to obtain water resource potential representation of upstream Citarum watersheed, that hystorically had higher rainfall than its downstream. Irrigation water requirement was calculated by Penman – Monteith method of water balance analysis, using CropWat for Windows version 8.0 software. The result of rainfall analysis showed that dry season in Pantura was occured from April until November (eight months), and wet season was occured from December until March (four months). The result of water balance analysis showed that soils in this region experienced water deficit during April to December. Analysis of aridity index showed that the coastal region Pantura experienced severe drought from June to October, with August as the peak. Water balance of Citarum river and Jatiluhur reservoir indicated that irrigation water demand for agricultural land in Pantura could not fulfilled only by Citarum River, so it need subvention from local resource. Moreover, calculation using CropWat for Windows showed that water requirement for all agricultural land in Pantura was 3.797,7 million m3/year, while data from PJT II showed that the average of irrigation water supply for this area was 5.519,6 million m3/year. It indicated that efficiency of the irrigation Jatiluhur channels was about 68,8%.
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Judul: Perubahan penggunaan lahan DAS Citarum dan dampaknya terhadap suplai air irigasi (studi kasus : periode tahun 2002-2009)
Abstrak: The research used secondary data between 2002 to 2009 in PJT II Jatiluhur and Citarum-Ciliwung watershed Management Agency. Generally, this research was done in Citarum watershed area, West Java province, from August to October 2010.The research aims to investigate: 1). Land use change in Citarum watershed area; 2). Effect of land use change on water yield; 3). Changes in water yield and its impact on irrigation needs; and 4). Effect of irrigation water supply to changes in rice acreage. According to the digital citra analysis, Citarum watershed area that located above Jatiluhur dams has changed land use (450.649 ha) between 2002 and 2008. In agriculture areas land use change significantly increased from 59.76% in 2002 to 70.52% in 2008. Changes in water results continue to demonstrate the value decreases with increasing area of agriculture following the equation ym = 2987.74-0.00766887x2 (x2 is an extensive agricultural area in ha; ym is the result of water in million m3/th). Decrease in water yield has not been an adverse impact on irrigation needs, seen from an index value of the use of water in the reservoir continues to decline, resulting in increased efficiency of reservoirs. Index decreased use of water reservoirs affected by the increase in annual precipitation, so as to reduce the effects of the decline that occurred in the water. Changes in area of rice fields terjadididuga because of land conversion to non-agricultural activities that are not triggered by lack of water.
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Judul: Grup dan Homomorfisma Grup pada Rubik Revenge
Abstrak: Rubik cube is a kind of puzzle game. A player must arrange rubik sides, which have been disordered, back to the position where every side has the same colour. This paper does not focus on the settlement solution, but instead on proving the existence of a group homomorphism between rubik movement group and S96 symmetric permutation group in rubik revenge. Firstly, it has been proved that rubik movement set is a group. Then, it also has been proved that the M set, which contains numeric labels of 1 until 96 in cubinos sides, is S96 symmetric permutation group.
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