Judul: Planning of Rainwater Reservoir as a Water Supply Alternative of Guest House Unit Bogor Barat Agrohills, Planning of Rainwater Reservoir as a Water Supply Alternative of Guest House Unit Bogor Barat Agrohills
Abstrak: Bogor Barat Agrohills terletak di Kabupaten Bogor dengan curah hujan 3619,34 mm/tahun. Kebutuhan air bersih di Bogor Barat Agrohills direncanakan bersumber dari sumur bor. Bogor Barat Agrohills yang direncanakan sebagai kawasan eduwisata memerlukan adanya alternatif lain yang ramah lingkungan untuk memenuhi kebutuhan air sehari-hari. Salah satu strategi yang dapat diterapkan adalah dengan menampung air hujan. Penelitian dari bulan Mei hingga Agustus 2022 ini bertujuan merencanakan sistem penampungan air hujan untuk alternatif penyediaan air bersih di Guest House Bogor Barat Agrohills. Analisis untuk perencanaan penampungan air hujan menggunakan data curah hujan tahun 2012 hingga 2021. Desain bak penampung menggunakan data curah hujan andalan maksimum pada bulan Maret sebagai batasan dalam perencanaan dengan curah hujan bulanan sebesar 705,3 mm. Total air yang dapat ditampung sebesar 4,40 m3 /hari. Ketersediaan air ini mampu memenuhi kebutuhan air bersih untuk dua unit Guest House yaitu sebesar 1,8 m3 /hari. Dimensi bak penampung air hujan berdasarkan perhitungan neraca air direncanakan memiliki panjang 5 m, lebar 5 m, dan tinggi 3,6 m dengan kapasitas tampungan sebesar 90 m3 . Total rencana anggaran biaya pembuatannya sebesar Rp110.814.500., Bogor Barat Agrohills is located in Bogor district with rainfall of 3619.34 mm/year. The need for clean water in the Bogor Barat Agrohills Guest House area is planned to be sourced from drilled wells. As an edutourism area, it is necessary to have other environmentally friendly alternatives to meet daily water needs. One of the strategy that can be applied is rainwater storage. This study, conducted in May until August 2022, aimed to plan a rainwater collecting system as an alternative to increase clean water availability at the Bogor Barat Agrohills Guest House. The design analysis of rainwater storage was conducted using rainfall data from 2012 to 2021. As a limitation in the design of the storage, the rainfall data used was the maximum reliable rainfall data in March with a monthly rainfall of 705.3 mm. The total water supply that could be accommodated was 4.40 m3 /day. The water availability of 1.8 m3 /day, is able to meet the clean water demand for two Guest House units. The dimensions of the rainwater storage based on the water balance calculation were planned with length of 5 m, width of 5 m, and height of 3.6 m with a storage capacity of 90 m3 . The total planned budget needed was IDR110,814,500.
Keyword: planned budget, rainwater storage, rainfall, water demand

Judul: Rainwater Harvesting System Design in International  Dormitory of IPB Dramaga Campus
Abstrak: Curah hujan yang tinggi di Bogor mencapai 3500 mm melebihi rata-rata curah hujan nasional antara 2000 – 3000 mm. Pemanenan air hujan cocok untuk dilakukan sebagai langkah konservatif yang dapat dilakukan IPB University dalam upaya pemeliharaan sumber daya air yang berkelanjutan. Penelitian ini bertujuan mengetahui banyaknya suplai air hujan yang dapat dipanen, menghasilkan desain sistem PAH serta RAB instalasinya, dan mengetahui penghematan air serta biaya yang dapat dicapai melalui sistem PAH. Penelitian dilakukan dari Februari – Mei 2024 dengan pengambilan data primer berupa luas atap bangunan dan informasi kebutuhan air bersih, serta data sekunder berupa curah hujan tahun 2000 – 2023 Stasiun BMKG Jawa Barat. Potensi volume air hujan yang dapat dipanen 1230 – 2134 m3 dengan rata-rata suplai 1603 m3 per tahun. Desain sistem pemanenan PAH yang dirancang menggunakan tangki FRP berkapasitas 28 m3 dengan dimensi 7 m x 2 m x 2 m. Talang dipasang dengan kemiringan seragam ½% dan pipa datar dengan kemiringan seragam 1%. Variasi ukuran pipa dan talang yang digunakan antara 1 – 10 inch. Besarnya biaya yang dibutuhkan untuk instalasi PAH sebesar Rp143.000.000,00. Penghematan air aktual yang dapat tercapai melalui sistem PAH sebanyak 44% – 75% dari kebutuhan air tahunan dan menghemat biaya lebih dari 120% dari investasi awal., High rainfall in Bogor reached 3500 mm, exceeding the national average rainfall between 2000 – 3000 mm. Rainwater harvesting is conservative step that IPB University can take to maintain sustainable water resources. This research aims to determine amount of rainwater supply that can be harvested, created PAH system design and installation RAB, and determine water and cost savings that can be achieved through PAH system. The research was conducted from February – May 2024 by collecting primary data of building roof area and information of clean water needs, and secondary data of rainfall from 2000 – 2023 from West Java BMKG Station. Potential harvested volume of rainwater is 1230 – 2134 m3 with average supply 1603 m3 a year. The harvesting system design uses a 28 m3 FRP tank with dimensions 7 m x 2 m x 2 m. The gutter is installed with slope of ½% and the flat pipe with slope of 1%. Variations in pipe and gutter sizes used are between 1 – 10 inches. The cost required for PAH installation is IDR143,000,000.00. Actual water savings that can be achieved through PAH system are 44% – 75% of annual water needs and cost savings of more than 120% of the initial investment.
Keyword: air hujan, ketersediaan air, konservasi air, pemanenan air hujan, rainwater, rainwater harvesting, water availability, water conservation

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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