Judul: Dampak Keberadaan Tempat Pembuangan Akhir Sampah (TPAS) “Namo Bintang” terhadap Masyarakat (Studi Kasus: Desa Namo Bintang, Kecamatan Pancur Batu, Kabupaten Deli Serdang)
Abstrak: “Namo Bintang” landfill is located in Pancur Batu sub-district, Deli Serdang Regency. “Namo Bintang” landfill is one of the landfill in Medan that use the "open dumping" system. The open dumping waste management system usually affect more negative externalities such as reducing the level of health care and environmental deterioration. At the other side, it could also provides positive impact for the society such as a source of income and added value gathered from waste processing. Based on that problems, thus it’s important to identify society and labor perceptions, the estimation of positive impact and negative externalities, and factors that affect the environmental deterioration due to the existence of the “Namo Bintang” landfill. The result showed that respondents have good perceptions about the condition of natural resources and environmental. The positive impact that arising from the existence of the landfill are the absorption of labor and value added of trash into compost which is analyzed using Hayami Analysis Added Value Method. The added value of fertilizer compost is IDR 100,546 which is 43,251% per kilogram of raw material and produce a big profit IDR 15,477 per kilogram raw material that processed of 15,369%. The estimation of the negative externalities seen from the society expense for health care costs with approach of the cost of illness and clean water consumption with replacement cost approach. Based on the calculations, total calculation for health care IDR 56.249.600 per month and clean water consumption cost IDR 108.350.792 per month, so the negative externalities value are IDR 164.600.392 per month. The factors that affect the environmental deterioration cost measured from the cost of clean water consumption by using Multiple Linear Regression Analysis. Based on regression analysis, there are five variables that affect the expense which is income level, occupation, number of dependents, distance to “Namo Bintang” landfill, and the environmental clean. Therefore, the result of this research can be used as a consideration material for the government in Medan for the management development and for better cultivation in “Namo Bintang” landfill.
Keyword: Open Dumping, “Namo Bintang” Landfill, Landfill, Environmental Deterioration, Compost Fertilizer

Judul: Public Perception Analysis and Willingness To Pay (WTP) Estimation on TPS 3R as Alternative of Waste Management System (Case Study: Kelurahan Pondok Karya, Kecamatan Pondok Aren, South Tangerang City)
Abstrak: Keterbatasan lahan Tempat Pemrosesan Akhir (TPA) Cipeucang untuk menampung timbulan sampah akan berimplikasi pada timbulnya Tempat Penampungan Sementara (TPS) secara liar di Kota Tangerang Selatan. TPS liar menggunakan sistem konvensional yang akan menimbulkan dampak negatif pada lingkungan pemukiman, salah satunya di Kelurahan Pondok Karya. Paradigma sistem konvensional harus ditinggalkan dan diperbaharui dengan pola pendekatan berbasis masyarakat seperti TPS 3R (reduce, reuse, recycle). Tujuan penelitian ini adalah: (1) mengidentifikasi upaya pemerintah terhadap rencana penyelenggaraan TPS 3R, (2) mengidentifikasi persepsi masyarakat terhadap pengelolaan sampah saat ini dan tingkat partisipasi terhadap rencana penyelenggaraan TPS 3R, (3) mengestimasi nilai Willingness to Pay (WTP) masyarakat, dan (4) menganalisis faktor-faktor yang mempengaruhi besarnya nilai WTP masyarakat. Penelitian ini menggunakan metode analis deskriptif, analisis skala likert, Contingent Valuation Methode (CVM), dan analisis regresi logistik ordinal. Hasil penelitian menunjukan adanya upaya pemerintah berupa peningkatan kegiatan sosialisasi serta pemberian bantuan dana pada pembangunan TPS 3R. Masyarakat sangat setuju bahwa pengelolaan sampah saat ini tidak layak baik dari aspek sosial, lingkungan, maupun ekonomi. Tingkat partisipasi masyarakat sangat tinggi untuk mendapat pengelolaan sampah yang lebih baik. Rataan nilai WTP sebesar Rp 40.100/KK/bulan akan digunakan untuk pembiayaan operasional TPS 3R. Faktor yang mempengaruhi besaran nilai WTP adalah lama tinggal, tingkat pendapatan, status tempat tinggal, dan pendidikan., The problem of limited capacity of Cipeucang landfill (TPA) to accommodate the urban waste cause the emergence of illegal temporary landfill (TPS) in South Tangerang. The illegal TPS is using the conventional waste management system which creates negative effects for the surrounding residential areas, including Kelurahan Pondok Karya. The conventional waste management system must be replaced with the new community-based approach , such as TPS 3R (reduce, reuse, recycle). The aims of this study are; (1) identifying the government plan to execute TPS 3R; (2) identifying people’s perception regarding to the current waste management and people’s participation level to TPS 3R execution plan; (3) estimating people’s Willingness to pay, and; (4) analyzing the factors that influence people’s WTP. This study used a descriptive analytical method, likert scale, Contingent Valuation Method (CVM), and ordinal logistic regression. The result of this study shows that government has conducted socialization on TPS 3R and provide budget for TPS 3R establishements. People strongly agree that the current waste management is not feasible in social, environmental and economic aspects. People's level of participation to get a better waste management was high. Mean of WTP value was Rp 40.100,00/household/month and would be used to finance the TPS 3R operational costs. Factors that influenced the WTP are period of stay, level of income, residence status, and level of education.
Keyword: biaya operasional, persepsi masyarakat, regresi logistik ordinal, TPS liar

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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