Judul: Analisis Persepsi Nasabah dan Manfaat Ekonomi Pengelolaan Bank Sampah (Studi Kasus : Bank Sampah Malaka Sari, Jakarta Timur)
Abstrak: Salah satu alternatif dari pengelolaan sampah berbasis masyarakat yang dilakukan pemerintah adalah program bank sampah. Program ini diharapkan dapat meningkatkan kesadaran masyarakat akan pentingnya lingkungan hidup yang bersih dan sehat serta dapat membuat sampah menjadi barang yang memiliki nilai ekonomi. Bank Sampah Malaka Sari merupakan Bank Sampah pertama yang terdapat di DKI Jakarta dan merupakan bank sampah yang mengalami penutupan sementara untuk mengurangi penyebaran virus COVID-19 pada tahun 2020. Penelitian ini bertujuan untuk menganalisis persepsi nasabah aktif menggunakan analisis skala likert, mengestimasi manfaat ekonomi menggunakan analisis pendapatan, mengestimasi besaran share pendapatan nasabah aktif dengan analisis deskriptif. Hasil penelitian menunjukan bahwa persepsi nasabah aktif terhadap pengelolaan Bank Sampah Malaka Sari sangat baik. Manfaat ekonomi yang dihasilkan dari pengelolaan Bank Sampah Malaka Sari bernilai positif, yaitu pada tahun 2019 sebesar Rp 5.421.303 dan tahun 2020 sebesar Rp 2.762.758. Besaran share pendapatan yang dihasilkan nasabah dari menabung di bank sampah setiap bulan pada tahun 2019 1,33% dan tahun 2020 sebesar 1,11%, persentase ini menurun karena operasional Bank Sampah Malaka Sari berhenti sementara karena pandemi COVID-19., Waste bank program is one of the communit based waste management system. This program is expected to increase public awareness of the importance of a clean and healthy environment and can turn waste into goods that have economic value. The Malaka Sari Waste Bank is the first Waste Bank in DKI Jakarta and is a waste bank that is temporarily closed to reduce the spread of the COVID-19 virus in 2020. This study aims to analyze the perception of active customers using Likert scale analysis, estimate the economic benefits using analysis income, estimating the size of the share of active customers' income with descriptive analysis. The results showed that the perception of active customers on the management of the Malaka Sari Waste Bank was very good. The economic benefits generated from the management of the Malaka Sari Waste Bank are positive, amounted in 2019 is Rp. 5.421.303 and in 2020 is Rp. 2.762.758. The amount of revenue sharing generated by customers from savings in waste banks every month in 2019 was 1,33% and in 2020 by 1,11%, this percentage decreased because the operations of the Malaka Sari Waste Bank were temporarily suspended due to the COVID-19 pandemic.
Keyword: income analysis, likert scale analysis, share income, waste management

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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