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: Economic Benefits and Sustainable Waste Management Strategies (Case Study: RW 08 Merbabu Waste Bank, Larangan Village, Harjamukti District, Cirebon City).
Abstrak: Pengelolaan sampah membutuhkan paradigma baru yang lebih banyak melibatkan partisipasi masyarakat dan lebih menekankan pengurangan sampah dari sumbernya. Bank sampah menjadi salah satu kegiatan yang bisa membantu pengurangan sampah. Pelaksanaan operasional bank sampah memiliki kendala internal maupun eksternal, salah satunya adalah wabah pandemi COVID-19. Penelitian ini bertujuan menghitung manfaat ekonomi bank sampah sebelum dan saat awal pandemi COVID-19 yaitu tahun 2019 dan 2020 menggunakan pendekatan analisis pendapatan, menganalisis pola perilaku nasabah menggunakan analisis deskriptif dan mengukur persepsi nasabah terhadap kinerja bank sampah dari aspek ekonomi, sosial dan lingkungan menggunakan skala likert, serta penyusunan strategi keberlanjutan bank sampah menggunakan Analytical Hierarchy Process (AHP). Hasil penelitian menunjukkan manfaat ekonomi yang diperoleh Bank Sampah RW 08 Merbabu dari tahun 2019 hingga 2020 mengalami penurunan yaitu Rp. Rp 547.200 per tahun menjadi Rp. Rp153.500 per tahun atau menurun sebesar 71,9%. Meskipun ada pandemi COVID-19, hanya sedikit nasabah yang mengalami perubahan motivasi dalam pemilahan sampah. Secara keseluruhan Bank sampah RW 08 Merbabu sudah memberikan dampak dari aspek ekonomi, sosial dan lingkungan kepada nasabah. Strategi pengelolaan bank sampah yang berkelanjutan dapat dicapai melalui peningkatan sosialisasi dan promosi keberadaan bank sampah lebih sering kepada masyarakat di RW sekitar., Waste management requires new paradigm that involves more communities participation and emphasizes reducing waste at source. Waste bank is one of the activities that can help waste reduction. The implementation of waste bank operations has internal and external constraints, one of them is COVID-19 pandemi. This study aims to calculate the economic benefits of waste banks before and at the beginning of the COVID-19 pandemi in 2019 and 2020 using an income analysis approach, to analyze behavior patterns and perceptions of waste banks customer using descriptive analysis, to measure the performance of waste banks from the economic, social and environmental aspect through Likert scale, to formulate strategies for waste bank sustainability using the Analytical Hierarchy Process (AHP). Based on the result, the economic benefits obtained in RW 08 Merbabu Waste Bank from 2019 to 2020 was decreased from Rp. IDR 547,200 per year to IDR. Rp153,500 per year (71.9%). Despite the COVID-19 pandemi, only a few customers experienced a motivation change in sorting waste. Overall, the Waste Bank RW 08 Merbabu has given impact on customers from economic, social and environmental aspects. Sustainable waste bank management strategy can be achieved through increasing socialization and promotion of the existence of waste banks more often to the surrounding area.
Keyword: Analytical Hierarchy Process, income analysis, perception, behavior pattern

Judul: Hamiltonian formulation for linear waves motion in two layers fluid
Abstrak: The surface wave could be considered as a wave that separates two fluids, namely water and air. Based on this assumption, it is introduced the interfacial wave, a wave between two layers of fluid with different density. The formulation of interfacial waves motion begins with deriving the base equation of irrotational ideal fluid. Furthermore, according to irrotational fluid assumption, the base equation can be stated in velocity potential. In this derivation, the fluids domain is assumed to be restricted by rigid lid boundary conditions, both at the upper and lower limit. Therefore, the interfacial waves motion can be explained in a hamiltonian formulation. In the hamiltonian formulation, total energy is defined as the sum of kinetic and potential energy. The hamiltonian system is obtained from reduction of kinetic energy by using the Dirichlet Neumann Operator. The resulted kinetic energy equation is nonlinear. Therefore, this form is linearized by first part of the Taylor expansion. This linearization gives a dispersion relation of linear wave. Based on this dispersion relation, the phase speed of the linear wave depends on the density ratio of the two layers fluid.
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