Judul: Studi Metode Infiltrasi Falling Head dan Constant Head pada Beberapa Variasi Ketinggian Genangan Air
Abstrak: Field measurement of infiltration rate using both of falling head and constant head method has an opportunity to generate different infiltration capacity values due to the different of hydraulic head and the way of water being added to infiltrometer. The purpose of this study was to compare the infiltration capacity based on falling head and constant head method and to see the effect of various hydraulic head in the infiltrometer on the infiltration capacity. Infiltration field measurement was done in Latosol Darmaga, Bogor. Falling head method was done in two different ways, namely within a certain time interval and within a certain water drop interval. Hydraulic head used during measurement were 10 cm, 15 cm, and 20 cm. The falling head and constant head method generated different infiltration capacity values. The falling head method based on time interval generated different values of infiltration capacity at 10 cm, 15 cm, and 20 cm hydraulic head of respectively 5.07 cm/hour, 6.13 cm/hour, and 4.67 cm/hour. The falling head method based on water drop interval at 10 cm, 15 cm, and 20 cm hydraulic head generated infiltration capacity values of respectively 17.47 cm/hour, 17.18 cm/hour, and 20.60 cm/hour. The constant head method at 10 cm, 15 cm, and 20 cm hydraulic head generated infiltration capacity values of respectively 15.77 cm/hour, 24.17 cm/hour, and 25.90 cm/hour. Infiltration field measurement using the falling head method either based on time interval or water drop interval did not show an increasing trend of infiltration capacity values due to the increase of hydraulic head. However, the infiltration field measurement using constant head showed an increasing trend of the infiltration capacity values due to the increase of hydraulic head.
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Judul: Evaluation of Infiltration and Permeability Values in Various Land Uses
Abstrak: Infitrasi dan permeabilitas tanah merupakan dua hal yang saling berkaitan. Permeabilitas tanah mempengaruhi infiltrasi tanah. Laju infiltrasi konstan pada dasarnya ditentukan oleh nilai permeabilitas. Meskipun demikian, terdapat beberapa kasus bahwa nilai infiltrasi jauh lebih tinggi daripada nilai permeabilitas. Hal itu mengindikasikan adanya ketidakselarasan pada kedua parameter tersebut sehingga perlu diteliti. Penelitian ini bertujuan untuk mengevaluasi ketidakselarasan nilai infiltrasi dan permeabilitas tanah serta mengindentifikasi faktor-faktor penyebab ketidakselarasan tersebut. Metode yang digunakan dalam penelitian ini adalah dengan menduplikasi penetapan permeabilitas dan infiltrasi dari penelitian sebelumnya dan melakukan pengukuran di lapang untuk mengidentifikasi faktor-faktor penyebab ketidakselarasan tersebut. Hasil penelitian menunjukkan konsistensi nilai infiltrasi konstan yang lebih tinggi dari permeabilitas seperti halnya pada penelitian sebelumnya. Hasil analisis menunjukkan bahwa ketidaselarasan terjadi akibat adanya sebaran air secara horizontal pada penetepan infiltrasi dan adanya penyumbatan pori tanah pada saat persiapan tanah untuk pengukuran permeabilitas., Infiltration and soil permeability are two things that are interrelated. Soil permeability affects soil infiltration. The constant infiltration rate is determined by the permeability. Even so, there are some cases where the infiltration value is much higher than the permeability value. This indicates that there is an inconsistency in the two parameters so that it needs to be investigated. This research aims to evaluate the inconsistency of infiltration value and permeability of the field and to identify the factors that cause the discrepancy. The method used in this research is to duplicate the determination of the permeability and infiltration from the previous research and conduct field observations to identify the factors causing the incompatibility. The results showed the consistency of the infiltration value which were higher than the permeability value with the previous research. This further strengthens that the misalignment is caused by the horizontal distribution of water in infiltration measuremen and the blockage of soil pores during soil preparation for permeability measurements.
Keyword: double ring infiltrometer, infiltrasi, metode pewarnaan, model infiltrasi, permeabilitas, double ring infiltrometer, infiltration, dye method, infiltration model, permeability

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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