Judul: Management of Sugarcane (Saccharum officinarum  L.) in the Operational Area of Madukismo Sugar Mill, PT Madubaru Yogyakarta,  with Specific Focus on March Assessment Accuracy and Production Realization
Abstrak: Tebu (Saccharum officinarum L.) termasuk komoditas tanaman yang banyak dibutuhkan dalam rumah tangga dan industri, sehingga produksi diperlukan untuk memenuhi permintaan. Tuntutan produksi yang tinggi mendorong perusahaan tebu agar teliti dalam memperkirakan total produksi mendatang. Metode untuk memperkirakan total produksi panen adalah taksasi produksi. Taksasi digunakan sebagai acuan dalam perencanaan panen agar dapat menghitung kebutuhan tenaga kerja, peralatan panen, serta kapasitas giling. Magang ini bertujuan mempelajari pengelolaan tebu secara aspek budidaya dan aspek manajerial. Aspek khusus yang dipelajari adalah ketepatan taksasi tebu pada bulan Maret dengan realisasi produksi di kebun tebu PG Madukismo, PT Madubaru, Yogyakarta di wilayah Sleman dan Bantul. Analisis data menggunakan uji homogenitas t-student dengan taraf kesalahan 5%. Nilai taksasi produksi di PG Madukismo secara umum belum mencapai ketepatan yang baik karena perbedaan taksasi-produksi di luar batas yang ditentukan yakni 95%. Nilai ketepatan taksasi tahun 2023 pada Rayon Bantul yakni 100,25% dan Rayon Sleman 106,46%. Mayoritas kebun di Rayon Bantul dan Rayon Sleman belum memenuhi standar ketepatan taksasi-produksi PG Madukismo meskipun secara rata-rata selisihnya tidak lebih dari 5%. Upaya yang dapat dilakukan untuk meningkatkan ketepatan taksasi-produksi yakni dengan memperhitungkan kemungkinan adanya kehilangan hasil tebu yang disebabkan oleh beberapa faktor seperti panen dengan tunggul tinggi, serangan hama dan penyakit, kerusakan akibat cuaca buruk, serta ketelitian pengamatan dalam perhitungan taksasi., Sugarcane (Saccharum officinarum L.) is a commodity plant highly demanded in households and industries, making its production essential to meet the demand. The high demand for production drives sugarcane companies to be meticulous in estimating future total output. One method used for this is production appraisal. Appraisal is used as a reference in harvest planning to calculate labor requirements, harvest equipment, and milling capacity. This internship aims to study sugarcane management from both cultivation and managerial perspectives. The specific aspect under study is the accuracy of sugarcane appraisal in March compared to the realized production in the sugarcane plantations of PG Madukismo, PT Madubaru, Yogyakarta, in the Sleman and Bantul regions. Data analysis employs the t-student homogeneity test with a 5% error margin. The overall production appraisal values at PG Madukismo have not yet reached a good accuracy level due to differences between appraisal and production beyond the specified threshold of 95%. The accuracy values for the year 2023 in the Bantul Region were 100,25%, and in the Sleman Region were 106,46%. The majority of plantations in the Bantul and Sleman Regions have not met the accuracy standard of PG Madukismo's appraisal-production, although the average difference is not more than 5%. Efforts to improve the accuracy of appraisal-production include considering the possibility of sugarcane yield losses caused by factors such as harvest with tall stakes, pest and disease attacks, damage due to adverse weather conditions, and the precision of observation in appraisal calculations.
Keyword: harvest, losses, planning, region, standard

Judul: Pengelolaan Tanaman Tebu (Saccharum officinarum L.) di Pabrik Gula Madukismo, PT. Madubaru, Yogyakarta: dengan Aspek Khusus Mempelajari Produktivitas Tiap Kategori Tanaman
Abstrak: The study of the productivity of the various categories of sugarcane held in the Madukismo Millsworking area, Madubaru Company, Yogyakarta. This activity began in February 13 to May 14, 2012. The sample is taken at Sleman and Bantul district. The method used is the direct field observation, data from the division of plant productivity, as well as interviews with farmers. The results obtained on the productivity of down land is higher than up land. Differences in land characteristics influence the productivity of sugarcane. In addition, the downland productivity tended to decrease from the plant cane (PC) to ratoon crop (RC) in each subsequent season. For up land, there is higher productivity at ratoon cane I (RC 1) increase from low productivity in the plant cane (PC) and then back on every ratoon crop the following season. To overcome the low productivity of ratoon sugarcane needed to do the loading or replanting, or ratoon intensif nurse.
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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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