Judul: Dampak ekonomi sosial dan Lingkungan pemanfaatan limbah ternak sapi perah di Kampung Areng Desa Cibodas Kecamatan Lembang Kabupaten Bandung Barat
Abstrak: Indonesia has great beef cattle population potentially cause pollution from livestock waste. Utilization of livestock waste into biogas as an alternative energy is a solution. This study analyzed the perception of the respondents about the use of livestock waste into biogas, analyzed the factors that influence the decision of breeders in use livestock waste into biogas, to analyze the changes of energy consumption before and after the use of biogas and energy consumption cost difference between the farmers types I and II, and analyzed the impact of social and environment from the use livestock waste into biogas. The research results show that the majority of respondents have that utilization of livestock waste into biogas have direct and indirect benefit for breeders and community around location. Significant factors that influence th breeders decision to use biogas is long of cattle business, the number of livestock, the level of education , and the participation of the group of cattle. The results showed that the rate of dairy cattle business income type I is higher than type II with the the total value income of Rp 200.970 /month . The difference in the cost of energy consumption between the two types of cattle business Rp 22.050. The social and environment impact from the utilization of livestock waste into biogas are improve cultural cooperation communities, improve the performance of the group of cattle, changes in environmental conditions around the cage cleaner, and reduced air pollution due to a heap of livestock waste.
Keyword: Bogor Agricultural University, the impact of economicsocial and environment, logistic regression, livestock waste, biogas

Judul: Analisis Pendapatan Dan Faktor Yang Memengaruhi Pemanfaatan Limbah Ternak Sapi Perah (Kampung Areng, Desa Cibodas, Kecamatan Lembang, Kabupaten Bandung Barat)
Abstrak: Sub sektor peternakan memiliki peran yang strategis dari sisi pembangunan ekonomi nasional, di antaranya berkontribusi terhadap Produk Domestik Bruto sebesar Rp 145 720 milyar pada tahun 2012, serta sebagai sumber energi alternatif terbarukan dari pemanfaatan kotoran ternak menjadi biogas. Biogas menjadi salah satu solusi untuk mencukupi kebutuhan energi sektor rumah tangga yang semakin meningkat dengan laju pertumbuhan sekitar 0.88% per tahun. Penelitian ini menganalisis pendapatan usahaternak sapi perah tipe I dan II, menganalisis perubahan konsumsi energi sebelum dan sesudah penggunaan biogas dan selisih biaya konsumsi energi antara peternak tipe I dan II, serta mengidentifikasi faktor-faktor yang memengaruhi keputusan pemanfaatan biogas. Metode yang digunakan adalah analisis pendapatan dan analisis regresi logistik. Hasil penelitian menunjukkan bahwa tingkat pendapatan usahaternak sapi perah tipe I lebih besar dibandingkan tipe II dengan nilai selisih pendapatan sebesar Rp 146 273/bulan/ST. Konsumsi energi berkurang sebanyak dua kali lipat, dan selisih biaya konsumsi energi diantara kedua tipe usahaternak sebesar Rp 182 560. Faktor-faktor yang berpengaruh signifikan terhadap keputusan peternak untuk menggunakan biogas di antaranya jumlah ternak, pengeluaran untuk membeli gas elpiji, jenis kelamin, dan tingkat pendidikan responden. Nilai R/C rasio yang dihasilkan lebih besar dari satu, sehingga usahaternak menguntungkan.
Keyword: biogas, pendapatan usahaternak, penghematan energi, regresi logistik

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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