Judul: Optimalisasi Peralatan Pemanenan Kayu pada Hutan Tanaman Industri di IUPHHK-HT PT Musi Hutan Persada, Provinsi Sumatera Selatan.
Abstrak: Untuk mencapai efisiensi waktu dan biaya produksi pemanenan kayu diperlukan pengoptimalan dalam penggunaan jumlah alat pemanenan kayu yang tepat. Penelitian dilaksanakan di areal kerja hutan tanaman PT Musi Hutan Persada, Provinsi Sumatera Selatan. Penelitian ini bertujuan untuk menentukan penggunaan jumlah peralatan pemanenan kayu yang optimal berdasarkan produktivitas alat dan target produksi. Hasil penelitian menunjukan bahwa jumlah alat pemanenan kayu dari tahapan penebangan sampai pengangkutan terdapat kelebihan dan kekurangan alat. Alat pemanenan kayu yang ideal berdasarkan target produksi terdiri atas 2 unit Shearhead dan 10 unit Harvester untuk kegiatan penebangan, 9 unit Forwarder dan 1 unit Wheel Skidder untuk kegiatan penyaradan, 3 unit Excavator Grapple untuk kegiatan pemuatan, serta 69 unit Logging Truck untuk kegiatan pengangkutan. Skenario jumlah alat ideal ini lebih menguntungkan perusahaan karena mengurangi biaya produksi alat yang tidak diperlukan.
Keyword: jumlah alat, optimalisasi, pemanenan kayu

Judul: Optimalisasi Peralatan Pemanenan Kayu pada Hutan Tanaman Industri di IUPHHK-HT PTWirakarya Sakti, Provinsi Jambi
Abstrak: Harvesting of forest products is one of the principal activities of forest management. Optimization of timber harvesting equipments is needed to produce output that can cover the production costs. This study aimed to determine the amount of the optimal timber harvesting equipments based on work productivity, production realization and production targets. This study designed five scenarios of harvesting equipments user. The two scenarios used to achieve the production realization while the others used to achieve the production targets. Scenarios are used to achieve the production realization are (1) the actual equipments amount (AEA) with production costs IDR349 245/m3 or IDR29.77 billion/year and (2) the realization equipments amount (REA) with production costs IDR349 245/m3 or IDR29.21 billion/year. The others scenarios used to achieve production targets are (1) the target equipments amount (TEA) with production costs IDR349 245/m3 or IDR40.65 billion/year, (2) the combinations equipments amount (CEA) with production costs IDR281 975/m3 or IDR29.41 billion/year, and (3) the new equipments amount (NEA) with production costs IDR208 110/m3 or IDR16.84 billion/year.
Keyword: timber harvesting, production costs, optimization

Judul: Metrik Einstein (Anti-) Self-Dual Berdimensi Empat dengan Metode Cartan
Abstrak: Gravitational field equation can be formulated in differential forms (differential geometry), which describes gravity as a manifestation of the curvature of space-time. Curvature of space-time is characterized by a metric that satisfies the gravitational field equation. With differential forms it can be formulated the (anti-) self-dual Einstein equation, which is a modification of the Cartan structure in (anti-) self-dual basis. Calculation of (anti-) self-dual metric with (anti-) self-dual Einstein equation is simpler than the calculation using Christoffel symbols.
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