Judul: Financial Feasibility Analysis of Waste Management Through Waste Bank (Case Study of the Waste Bank of Warung Jambu Bersih, Bogor City)
Abstrak: Sampah yang sudah tidak dapat dipergunakan, kadaluwarsa, rusak, tidak memiliki nilai dan menjadi timbunan barang, masih bisa memiliki nilai ekonomis yang dapat dijual kembali dengan adanya bank sampah. Pada tahun 2021 rata-rata timbulan limbah Kota Bogor sebesar 245.9 ribu ton dan rata-rata timbulan limbah perharinya sebesar 673 ton. Pengelolaan sampah melalui bank sampah dapat memperbaiki perekonomian masyarakat, menambah lapangan pekerjaan, dan meningkatkan kesadaran masyarakat untuk selalu menjaga lingkungan. Penelitian ini mempunyai tujuan yaitu: (1) menganalisis kelayakan investasi mendirikan bank sampah dari aspek kriteria kelayakan investasi di Bank Sampah Warung Jambu Bersih, dan (2) menganalisis bagaimana kondisi kelayakan investasi bank sampah ketika terjadi adanya perubahan pada harga, produksi output, dan jumlah nasabah di Bank Sampah Warung Jambu Bersih. Metode yang digunakan dalam penelitian ini yaitu analisis biaya manfaat untuk menganalisis kelayakan finansial dan analisis nilai pengganti. Hasil penelitian ini menunjukkan bahwa : (1) Berdasarkan analisis kelayakan finansial dengan umur proyek selama 10 tahun, proyek pengelolaan sampah Bank Sampah Warung Jambu Bersih layak untuk dijalankan. Masing-masing nilai NPV Rp 30.362.792,97; BCR 4,17; IRR 38,4%, dan PP 3,17 Tahun. (2) Jumlah minimum agar bank sampah layak untuk dijalankan yaitu dengan produksi sampah minimum sebesar 469,8 kg/minggu, maksimum penurunan harga plastik sebesar Rp 492,5 /kg, dan minimum jumlah nasabah sebanyak 39 rumah tangga., Waste that is no longer usable, expired, damaged, has no value and becomes a pile of goods, but still have economic value that can be resold with a waste bank. In 2021 the average waste generation of Bogor City is 245.9 thousand tons and the average daily waste generation is 673 tons. Waste management through waste banks can improve the community's economy, increase job opportunities, and increase public awareness to always protect the environment. This study aims to: (1) analyze the investment feasibility of establishing a waste bank from the aspect of the investment feasibility criteria at the Bank Sampah Warung Jambu Bersih, and (2) analyze the condition of the investment feasibility of a waste bank when there are changes in prices, output production, and the number of customers at the Bank Sampah Warung Jambu Bersih. The method used in this research is cost benefit analysis to analyze financial feasibility and switching value analysis. The results of this study indicate that: (1) Based on a financial feasibility analysis with a project v 5 life of 10 years, the waste management project of the Warung Jambu Bersih Waste Bank is feasible to run. Each NPV value is IDR 28,925,048.33; BCR 5.37; IRR 38,4%, and PP 3.17 Years. (2) The minimum amount so that the waste bank is feasible to run is with a minimum waste production of 453.9 kg/week, a maximum reduction in plastic prices of Rp 472.5/kg, and a minimum number of customers as many as 39 households.
Keyword: cost benefit analysis, economical, environment, investment

Judul: The Impact of COVID-19 Pandemic on Warung Jambu Bersih Waste Bank Bogor City
Abstrak: Peningkatan timbulan sampah masih menjadi masalah di Kota Bogor sebagai dampak dari tingginya pertumbuhan penduduk dan kurangnya kesadaran masyarakat. Bank Sampah Warung Jambu Bersih telah mencoba mengambil peran dalam upaya mereduksi sampah di Kota Bogor, namun aktivitasnya harus berhenti akibat mewabahnya virus COVID-19. Tujuan umum penelitian adalah menganalisis dampak pandemi COVID-19 terhadap Bank Sampah Warung Jambu Bersih. Tujuan khusus penelitian yaitu untuk menganalisis persepsi nasabah terhadap dampak pengelolaan sampah di bank sampah, mengidentifikasi dampak pandemi terhadap bank sampah, mengestimasi perubahan nilai ekonomi sampah akibat pandemi, menganalisis keberlanjutan bank sampah, serta mengidentifikasi alternatif pengembangan bank sampah. Tujuan-tujuan tersebut dikaji dengan metode analisis deskriptif kualitatif dan kuantitatif, analisis skala Likert, dan RAPFISH-MDS. Hasil penelitian menunjukkan nasabah sangat setuju bahwa aktivitas bank sampah memberikan pengaruh positif dalam aspek sosial, ekonomi, dan lingkungan. Dampak pandemi COVID-19 terhadap keberlangsungan operasional bank sampah membawa implikasi sosial, ekonomi, dan ekologi. Nilai ekonomi sampah yang dikumpulkan nasabah pada bank sampah menurun hingga 84% akibat pandemi. Lebih jauh lagi, hasil analisis RAPFISH-MDS menunjukkan bahwa bank sampah kurang berkelanjutan. Dukungan pembinaan dan finansial dari pihak eksternal akan membantu keberlanjutan bank sampah., The increasing of waste generation is problematic in Bogor city due to high population growth and lack of public awareness. Warung Jambu Bersih Waste Bank was established to play a role in reducing the waste generation in Bogor city. However, its operation has been suspended due to COVID-19 pandemic. The general objective of this study is to analyze the COVID-19 pandemic’s impact on Warung Jambu Bersih Waste Bank. Furthermore, the specific objectives are: 1) to examine customers perceptions of waste bank; 2) to identify the pandemic’s impact on waste bank; 3) to estimate changes in economic value of waste due to pandemic; 4) to assess waste bank’s sustainability, and; 5) to identify alternatives strategy for waste bank development. Analytical methods used in this study are qualitative and quantitative descriptive analysis, Likert scale analysis, and RAPFISH-MDS. The results show that the customers strongly acknowledge that waste bank has positive impacts in social, economic, and environmental aspect, while the impact of pandemic on waste bank operation brings social, economic, and ecological implications. The economic value of waste collected at waste bank has declined by 84%, while the RAPFISH-MDS analysis reveals that waste bank is less sustainable. Development and financial support from external parties may help the waste bank’s sustainability.
Keyword: development, economic value, perception, sustainability

Judul: Metrik Einstein (Anti-) Self-Dual Berdimensi Empat dengan Metode Cartan
Abstrak: Gravitational field equation can be formulated in differential forms (differential geometry), which describes gravity as a manifestation of the curvature of space-time. Curvature of space-time is characterized by a metric that satisfies the gravitational field equation. With differential forms it can be formulated the (anti-) self-dual Einstein equation, which is a modification of the Cartan structure in (anti-) self-dual basis. Calculation of (anti-) self-dual metric with (anti-) self-dual Einstein equation is simpler than the calculation using Christoffel symbols.
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