Judul: The Characteristics of Types of Plastic Packaging Waste in the Upstream Segment of the Citarum River, Bandung, West Java
Abstrak: Sungai Citarum merupakan salah satu sungai terbesar di Jawa Barat yang memiliki banyak fungsi, namun memiliki permasalahan baik dalam kualitas air, pencemaran logam berat, juga pencemaran sampah. Tujuan penelitian ini untuk mengidentifikasi dan menganalisis karakteristik jenis sampah plastik kemasan di segmen hulu Sungai Citarum (hilir Sungai Cikapundung dan Nanjung), Bandung, Jawa Barat serta dampaknya ke perairan. Pengambilan contoh dilakukan di hilir Sungai Cikapundung, Kecamatan Bojongsoang dan Jembatan Nanjung, Desa Nanjung, pada bulan April hingga November 2021. Sampel sampah plastik kemasan dianalisis berdasarkan bobot dan kelimpahannya berdasarkan jenis plastiknya. Uji statistik Mann-Whitney digunakan untuk mengetahui beda nyata sampah kemasan yang ditemukan antara kedua stasiun dan Uji Kruskal Wallis untuk mengetahui pengaruh waktu pengambilan contoh. Hasil yang diperoleh menunjukkan jenis sampah plastik kemasan pada kedua stasiun didominasi oleh jenis PP (Polypropylene) dan jenis lainnya. Selain itu, jenis PET (Polyethylene Terephthalate) juga dominan ditemukan pada Stasiun Cikapundung, serta jenis PS (Polystyrene) pada Stasiun Nanjung. Sampah plastik tersebut bersifat toksik dan karsinogenik yang akan menurunkan kualitas perairan serta berbahaya bagi biota perairan., Citarum River is one of the largest rivers in West Java which has many functions, but has problems both in water quality, heavy metal pollution, and garbage pollution. The purpose of this study was to identify and analyze the characteristics of the types of plastic packaging waste in the upstream segment of the Citarum River (downstream of the Cikapundung and Nanjung Rivers), Bandung, West Java and their impact on the waters. Sampling was carried out in the downstream of the Cikapundung River, Bojongsoang District and Nanjung Bridge, Nanjung Village, from April to November 2021. Samples of plastic packaging waste were analyzed based on their weight and abundance based on the type of plastic. The Mann-Whitney statistical test was used to determine the significant difference in packaging waste found between the two stations and the Kruskal Wallis test to determine the effect of sampling time. The results obtained show that the type of plastic packaging waste at both stations is dominated by PP (Polypropylene) other types. Furthermore, the type of PET (Polyethylene Terephthalate) is also dominantly found at Cikapundung Station, and PS (Polystyrene) at Nanjung Station. The plastic waste is toxic and carcinogenic which will reduce water quality and be harmful to aquatic biota.
Keyword: plastic packaging waste, rivers pollution, toxic compounds, types of plastic

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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