Judul: Performance test of lapindo pitcher irrigation system on papper plant (Piper Ningrum L)
Abstrak: Nowadays, water crisis has been threathening agricultural activities in fulfilling sustainable food production expecially in dryland area. On the other side, there are a potentiality of using Lapindo mud for making irrigation pitcher which can be used for irrigate dryland agricultures effeciently. This study aims at testing the performance of the Lapindo pitcher irrigation system used to irrigate papper plant in a greenhouse. Two types of irrigation pitchers were used for the experiment. One has higher permeability 6.715 x 10-7 cm/s than the other 5.256 x 10-7 cm/s. After one month experiment, papper plants growed well but faster when using the higher permeable pitcher. From this study, Lapindo mud is very potential to be used as row material to make irrigation pitcher. It is hoped that this study will ease to handle Lapindo mudflow problem by utilizing it into a useful material.
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Judul: Perencanaan Sistem Jaringan Perpipaan Bertekanan untuk Irigasi Padi Sawah di Balai Besar Penelitian Tanaman Padi (Subang, Jawa Barat).
Abstrak: Indonesian Center for Rice Research (ICRR) is a research institute that need precision and high accuracy to strengthen the analysis of research at the institute. One of those research is water balance analysis that need infrastructure such as irrigation. The objective of this research was to design burried pressure pipeline network system for paddy irrigation which starts from the determination of the diameter to the structural analysis. Diameter determination is done by combining the Bernoulli and Darcy-Colebrook-White equation, whereas the structure analysis following the standard of American Water Works Association (AWWA) M41 for pipes made of ductile iron. The results of design indicated that the water from the inlet could not flow by gravity, thus requiring the pump with head difference between the inlet to the outlet was 2.73 m. The main pipe diameters were respectively 36, 30, 24, and 18 in the pipeline while the branch was uniformed with 8 in. Hydraulic gradient along the flow was positive and exceeded the minimum operating pressure at each node, making sure the water can flow throughout both the main and branch pipes. Results of the analysis of the structure of the pipeline due to external loading indicated that the total pressure was still below the maximum bending stress. Total pressure also remained under maximum pressure deflection. Therefore, the pipe can withstand a design load and secure from buckling factor and ring deflection.
Keyword: ductile iron, hydraulic gradient, Indonesian Center for Rice Research, irrigation, pressurized pipe

Judul: Penentuan Nilai Eigen dan Vektor Eigen dari Matriks Tridiagonal 2-Toeplitz dengan Pendekatan Polinomial Chebyshev
Abstrak: The eigenvalues and eigenvectors of a matrix can be determined by finding its characteristic polynomials. The characteristic polynomials of a tridiagonal 2-Toeplitz matrix is shown to be closely connected to polynomials which satisfy the Chebyshev recurrence relationship. If the order of the matrix is odd, then the eigenvalues are found explicitly in terms of the Chebyshev zeros and the eigenvectors are found in terms of the polynomials satisfying the recurrence relationship. For even ordered matrices, the situation is more complicated. The problem in these cases is that although the Chebyshev recurrence formula is still applied, its initial values are not generating Chebyshev polynomials
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