Judul: Pengembangan model pengelolaan sungai berbasis pada konsep ekohidrolik (studi kasus Sungai Lawo Kabupaten Soppeng Provinsi Sulawesi Selatan)
Abstrak: managing river environment. The ecological issues in this research is the vegetation grown in the river bank as flood retention, while hydraulical aspect refers to the flows of water in river bank to reduce flooding. The aims of the research were : 1) to develop a river management model based on ecohydraulic concept; to characterize the optimal width of riverbank and appropriate vegetation; 2) to develop government policies to support river management based on ecohydraulic concept, and 3) to study the implementation of the model at Lawo River of Soppeng Regency. The output of river management model can be used as the recommendation of demarcation line of the river, while the policies can be used as a basis of policies of local government. As the implementation of the models, the data were collected from the Lawo River South Sulawesi between May 2010 to December 2010. River management model is based on ecohydraulic concept, it uses six variables were rainfall intensity, channel roughness, water level (without management), land use score, flooding and the height of inundation. The policies model were developed in four steps : community participation level, study of social economic condition of community, study of effect social economic condition to the participation and study of policies of river management. The policies model can be used to determine scenarios and strategic activities which can effect the implementation of river management model. The optimal width of riverbanks at Lawo River varies between 100 m and 150 m with vegetation diameter between 10 cm and 20 cm. This implies to the flooding water level less then 2.5 m and velocity of flow can be reduced to 76%. The best scenario found in this research suggests the improvement of infrastructure in order to increase the value of land. The best government program is increasing the population of vegetation in the river bank.
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Judul: Modeling of Flood for Land Use Management (Case Study of Ciliwung Watershed)
Abstrak: Floods are one of the major disasters affecting many countries in the world year after year. It is an inevitable natural phenomenon occurring from time to time in all rivers and natural drainage systems. It causes damage to lives, natural resources and environment as well as the loss of economy and health. Floods represent complex problems because of its variety. Therefore, this variety cannot be studied or controlled only by one or two specific methods. The objectives of this research are to understand the process of flood events and its interaction with hydrometeorological components, to develop flood model for watershed management and to determine the effect of land use change to watershed discharge which indicates flood event. The research consists of four processes those are 1) Data Preparation, 2) Model Development, 3) Model Simulation and 4) Model Calibration and Validation. Data preparation was conducted for two kinds of data namely spatial data and tabular data. Model developed as numerical model of the hydrology of a river basin system. This model includes the response of watershed to precipitation, the actions of the river network as water flows through the river, the effect of land use changes, and the effect of engineering structures to the watershed. Model simulated by change land use as an input. Model calibrated by using water level data of field measurement in year 1996 and model validated by using water level data of field measurement in year 2000. The result of this reseach showed how the process based modeling is useful to model hidrological processes over the watershed. Precipitation is the main input for hidrology simulation and land use change gives the effect of water level in the watershed. The model which is built in this research can be used to evaluate runoff from different land use areas. For assessing the hydrological effects of land use changes on floods, three hypothetical scenarios, namely urbanization, deforestation and afforestation scenario, were considered made. It was found from the model simulation that the urbanization scenario has the higest negative impact on increasing water level. Deforestation has the second largest negative impact, while afforestation causes positive impact shown by decreasing water level. The result indicated that the urbanization produce the highest peak flow, followed by the deforestation and afforestation scenario. The simulated water level for the present land use is 84 cm, for the urbanization scenario 135 cm, deforestation scenario 92 cm, and afforestation scenario 59 cm. Accordingly, the urbanization scenario increases the peak discharge by 61%, the deforestation scenario increase 15%, and afforestation decrease by 19%.
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Judul: Transisi Fasa Materi Hadronik ke Materi Kuark pada Inti Bintang Neutron.
Abstrak: Bintang neutron terdiri dari beberapa lapisan yang disusun oleh materi nuklir yang berbeda dengan kerapatan yang semakin tinggi ketika mendekati pusat bintang. Inti luar bintang neutron disusun oleh materi hadronik (nukleon, lepton, dan hyperon), sedangkan inti dalam bintang neutron disusun oleh kuark-kuark bebas (up, down, strange) yang saling berinteraksi. Tujuan penelitian ini adalah mempelajari bagaimana transisi dari inti luar ke inti dalam bintang neutron dengan menggunakan pendekatan RMF (Relativistic Mean Field) untuk materi hadronik dan CIDDM (Confined Isospin Density Dependent Mass) untuk materi kuark. Tekanan transisi diperoleh ketika potensial kimia barion materi hadronik dan materi kuark bernilai sama. Nilai tekanan transisi dengan parameter SU6-TM1 sekitar 87 MeV/fm3 dan diperoleh massa maksimum bintang neutron yaitu 1.92M dengan jari-jari sekitar 8.62 km. Nilai tekanan transisi dengan parameter SU6-G2 sekitar 53 MeV/fm3 dan massa maksimum bintang neutron yaitu 1.88M dengan jari-jari sekitar 8.16 km. Jenis transisi fasa adalah orde satu ditandai dengan diskontinuitas dalam kerapatan energi (adanya mixed phase). Parameter-parameter pada model nuklir yang digunakan menyebabkan perbedaan kekakuan persamaan keadaan (EOS) dari materi hadronik dan materi kuark sehingga nilai tekanan transisi dari fasa hadronik ke fasa kuark juga berbeda.
Keyword: bintang neutron, persamaan keadaan, transisi fasa