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: Estimation of the Value of Externalities from the Existence of Landfills (Case Study: Maju Hamlet, Durian Village, Aceh Tamiang District)
Abstrak: Salah satu kota di Indonesia yang juga tidak lepas terkait masalah persampahan adalah Aceh Tamiang. Bertambahnya jumlah penduduk diiringi dengan pengelolaan yang belum memadai membuat volume sampah di Kabupaten Aceh Tamiang terus meningkat. Tempat Pembuangan Akhir (TPA) memiliki manfaat sebagai tempat pembuangan akhir sampah masyarakat. Pengelolaan sampah di Kabupaten Aceh Tamiang saat ini dinilai masih kurang ramah lingkungan yang menimbulkan dampak bagi masyarakat sekitar. Dampak yang ditimbulkan berupa eksternalitas positif maupun eksternalitas negatif. Eksternalitas positif dari keberadaan TPA Desa Durian yaitu adanya pendapatan masyarakat yang bersumber dari TPA, sedangkan Eksternalitas negatifnya yaitu adanya bau tidak sedap di sekitaran jalanan tempat tinggal masyarakat, air sampah yang jatuh dari truk pengangkutan, dan lalat yang berada di rumah masyarakat. Berdasarkan hal tersebut tujuan dari penelitian ini yaitu (1) Menganalisis persepsi masyarakat mengenai kondisi lingkungan sekitar TPA. (2) Mengestimasi nilai eksternalitas dari keberadaan TPA. Metode yang yang digunakan dalam penelitian ini adalah analisis pendapatan, rating scale, cost of illness, dan preverentif cost. Hasil penelitian menunjukan bahwa masyarakat menilai keberadaan TPA Desa Durian berdampak terhadap kualitas lingkungan. Estimasi nilai eksternalitas positif dari keberadaan TPA Desa Durian lebih besar dibandingkan dengan nilai eksternalitas negatif yang dirasakan masyarakat sekitar TPA Desa Durian., One of the cities in Indonesia that is also related to waste problems is Aceh Tamiang. The increase in population accompanied by inadequate management makes the volume of waste in Aceh Tamiang Regency continue to increase. Landfills have the benefit og being the final disposal site for community waste. Waste management in Aceh Tamiang Regency is currently considered less environmentally friendly which has an impact on the surrounding community. The impacts can be in the form of positive externalities and negative externalities. The postivie externality of the existence of the Durian Village Landfill is the community income that comes from the landfill, while the negative externality is the unpleasant odor around the streets where people live, garbage water that falls from the transportation truck, and flies in people’s homes. Based on this, the objectives of this study are (1) Analyzing community perceptions of environmental conditions around the landfill. (2) To estimate the ecternality value of the landfill. The methods used in this research are income analysis, rating scale, cost of illness, and preventive cost. The result showed that the community considered the presence of the Durian Village landfill to have an impact on environmental quality. The estimated value of positive externalities from the existence of the Durian Village Landfill is greater than the value of negative externalities felt by the community around the Durian Village Landfill.
Keyword: Kerugian ekonomi, persepsi masyarakat, cost of illness, Manfaat Ekonomi, Rating Scale

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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