Judul: Pengaruh Kenaikan Harga Kedelai Terhadap Struktur Biaya dan Keuntungan Usaha Tempe (Studi Kasus: Rumah Tempe Indonesia di Bogor)
Abstrak: Tempe is a processed product which has a high nutritional value. Tempe businesses are generally run by household and small industries. Tempe produced by RTI consist of genetic modifier organism and Non-genetic modifier organism soybean. This research had only analyzed GMO tempe produced of 450gr and 700gr package. The increase in soybean prices are expected to give effect to the business craftsmen tempe in this case the business RTI. This study aims to analyze the cost structure of the soybean business in RTI before rising soybean prices and the impact of price rise of soybean in terms of the feasibility analysis (R/C ratio and break-even point (BEP). The results showed that the increase in soybean prices affect revenue of RTI. But R/C ratio was rising after the price rise of soybean. Based on these conditions, RTI is advised to improve the amount of their market because of RTI’s market which are segmented.
Keyword: the break-even, R/C ratio, sales revenue, GMO

Judul: Factors Affecting Production and Profit of Tempe Business in Pejaten Village, Kramatwatu District, Serang Regency
Abstrak: Konsumsi olahan kedelai seperti tempe cukup tinggi di Indonesia, dimana salah satu sentra produksi tempe berada di Desa Pejaten, Kecamatan Kramatwatu. Kedelai yang digunakan dalam pembuatan tempe adalah kedelai impor yang sering mengalami kenaikan harga. Maka menjadi penting apakah dengan harga bahan baku kedelai yang semakin naik, usaha tempe masih menguntungkan. Penelitian ini bertujuan untuk menganalisis faktor-faktor yang memengaruhi produksi, menganalisis struktur biaya usaha, dan menganalisis keuntungan usaha tempe di Desa Pejaten. Responden yang digunakan adalah keseluruhan perajin tempe di Desa Pejaten yakni sebanyak 25 orang. Metode analisis menggunakan analisis fungsi produksi, perhitungan keuntungan usaha, dan rasio R/C. Pengolahan data dibantu dengan program SPSS 26 dan Microsoft Excel. Hasil penelitian menunjukkan bahwa secara parsial, hanya variabel kedelai (X_1) yang berpengaruh nyata dan poisitif terhadap produksi tempe. Adapun komponen biaya terbesar dalam usaha tempe adalah biaya pembelian kedelai (80,53%), upah tenaga kerja (9,06%), dan biaya pembelian kemasan plastik (3,53%). Sedangkan rata-rata keuntungan usaha tempe yang diperoleh dalam sebulan adalah sebesar Rp. 4,308,824.71 dengan R/C rasio sebesar 1.14, maka usaha tempe sudah menguntungkan., Consumption of processed soybeans such as tempeh is quite high in Indonesia, where one of the centers for tempeh production is in Pejaten Village, Kramatwatu District. Soybeans that used in making tempeh are imported soybeans, which often had price increases. So it becomes important whether the price of soybean is increasing, the tempe business is still profitable. This study aims to analyze the factors that influence production, analyze the cost structure of the business, and analyze the profits of the tempeh business in Pejaten Village. Respondents used were all tempe craftsmen in Pejaten Village, as many as 25 people. The method of analysis uses the analysis of the production function, the calculation of operating profits, and the R/C ratio. Data processing is assisted by SPSS 26 and Microsoft Excel programs. The results showed that partially, only soybean variable (X_1) had a significant and positive effect on tempe production. The largest cost components in the tempe business are the cost of purchasing soybeans (80.53%), labor wages (9.06%), and the cost of purchasing plastic packaging (3.53%). Meanwhile, the average profit of tempeh business in a month is Rp. 4,308,824.71 with an R/C ratio of 1.14, then the tempe business is already profitable.
Keyword: cost structure, production function, R/C ratio

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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