Judul: Pencemaran Sampah Padat di Sungai Citarum, Provinsi Jawa Barat
Abstrak: Sungai Citarum merupakan salah satu sungai besar yang melintas di Provinsi Jawa Barat yang dimanfaatkan oleh masyarakat untuk berbagai keperluan, namun kondisi sungai pada beberapa lokasi mengalami pencemaran sampah padat. Tujuan penelitian ini untuk menganalisis kelimpahan dan komposisi sampah padat yang ditemukan di permukaan perairan serta menentukan hubungan antara sebaran sampah padat, curah hujan, dan debit air pada Sungai Citarum, Jawa Barat. Pengambilan contoh dilakukan pada lima titik stasiun pada bulan April hingga Juni dan bulan Agustus hingga November 2021. Sampah padat yang ditemukan pada Sungai Citarum adalah tipe sampah organik dan anorganik. Sampah organik merupakan tipe sampah yang mendominasi pada setiap lokasi. Kelimpahan sampah padat tertinggi di Sungai Citarum berasal dari bagian hulu, terutama wilayah perkotaan. Kelimpahan sampah padat relatif sama pada pagi, siang, dan sore hari. Curah hujan tidak berpengaruh terhadap kelimpahan sampah padat, sementara debit memiliki pengaruh yang lemah., The Citarum River is one of the major rivers that crosses West Java Province which is used by the community for various purposes, however, the condition of the river in several locations is polluted by solid waste. The purpose of this study was to analyze the abundance and composition of solid waste found on the surface of the waters and to determine the relationship between the distribution of solid waste, rainfall and water discharge in the Citarum River, West Java. Sampling was carried out at five station points from April to June and August to November 2021. The solid waste found in the Citarum River is a type of organic and inorganic waste. Organic waste is a type of waste that dominates at each location. The highest abundance of solid waste in the Citarum River comes from the upstream, especially urban areas. The abundance of solid waste is relatively the same in the morning, afternoon and evening. Rainfall has no effect on the abundance of solid waste, while discharge has a weak effect.
Keyword: kelimpahan, komposisi, sampah padat, Sungai Citarum

Judul: Komposisi dan Kelimpahan Makroplastik di Sungai Citarum (Sebelum dan Sesudah Waduk Saguling), Jawa Barat
Abstrak: Sungai Citarum merupakan sungai yang mengaliri tiga bendungan besar dan banyak dimanfaatkan oleh manusia dalam menjalankan aktivitasnya yang menghasilkan makroplastik sehingga terganggunya fungsi ekosistem. Tujuan penelitian ini untuk mengidentifikasi jenis dan jumlah makroplastik yang ada di Sungai Citarum, khususnya di lokasi sungai sebelum memasuki dan setelah outlet Waduk Saguling, berdasarkan perbedaan waktu, yaitu pagi, siang, dan sore. Pengambilan contoh dilakukan di Jembatan Nanjung, Desa Nanjung dan Jembatan Citarum Lama, Kecamatan Cipatat, pada bulan April hingga Juni 2021 dan bulan Agustus hingga November 2021. Sampel sampah plastik dianalisis kelimpahan dan komposisi jenis makroplastiknya. Uji statistik Kruskal Wallis, RLS, RLB, dan Korelasi digunakan untuk mengetahui beda nyata kelimpahan pada waktu pengamatan, dan pengaruh curah hujan terhadap kelimpahan. Hasil yang diperoleh menunjukkan kelimpahan makroplastik relatif sama antara waktu pengamatan, yaitu pagi, siang, dan sore hari. Curah hujan tidak berpengaruh terhadap kelimpahan makroplastik. Kelimpahan makroplastik paling tinggi ditemukan di Stasiun Nanjung pada sore hari. Sementara itu, komposisi jenis yang paling dominan ditemukan ialah kantung plastik bening, styrofoam, sachets, dan kemasan allumunium. Perbedaan kelimpahan pada kedua stasiun dipengaruhi oleh keberadaan Waduk Saguling di antara kedua stasiun., The Citarum River is a river that flows through three large dams and is widely used by humans in carrying out their activities that produce macroplastics so that ecosystem functions are disrupted. The purpose of this study was to identify the type and amount of macroplastic present in the Citarum River, especially at the location of the river before entering and after the outlet of the Saguling Reservoir, based on time differences, namely morning, afternoon, and evening. Sampling was carried out at Nanjung Bridge, Nanjung Village and Citarum Lama Bridge, Cipatat District, from April to June 2021 and August to November 2021. Plastic waste samples were analyzed for abundance and composition of macroplastic types. Kruskal Wallis, RLS, RLB, and Correlation statistical tests were used to determine the significant difference in abundance at the time of observation, and the effect of rainfall on abundance. The results obtained showed that the abundance of macroplastics was relatively the same between the time of observation, namely morning, afternoon, and evening. Rainfall has no effect on the abundance of macroplastics. The highest abundance of macroplastics was found at Nanjung Station in the afternoon. Meanwhile, the composition of the most dominant species found were clear plastic bags, Styrofoam, sachets, and aluminum packaging. The difference in abundance at the two stations is influenced by the presence of the Saguling Reservoir between the two stations.
Keyword: macroplastic, river, river discharge, species composition

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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