Judul: Optimalisasi Alat Pemanenan Kayu pada Hutan Alam di IUPHHK-HA PT Intrado Jaya Intiga Provinsi Kalimantan Tengah
Abstrak: Penggunaan jumlah alat pemanenan kayu yang tepat perlu dilakukan agar waktu dan biaya produksi pemanenan kayu menjadi efisien. Penelitian dilaksanakan di areal kerja hutan alam PT Intrado Jaya Intiga, Provinsi Kalimantan Tengah. Penelitian ini bertujuan menganalisis kebutuhan jumlah alat pemanenan kayu berdasarkan kepada produktivitas kerja, target produksi dan biaya peralatan pemanenan. Hasil penelitian menunjukan bahwa jumlah alat pemanenan kayu dari tahapan penebangan sampai pengangkutan terdapat kelebihan atau kekurangan alat. Alat pemanenan kayu yang efisien berdasarkan target produksi terdiri atas 1 unit chainsaw untuk penebangan, 2 unit track skidder dan 2 unit bulldozer untuk kegiatan penyaradan, 1 unit wheel loader untuk kegiatan pemuatan, 1 unit logging truck Mercy dan 1 unit logging truck Nissan untuk kegiatan pengangkutan, serta 1 unit wheel loader untuk kegiatan pembongkaran. Jumlah alat pemanenan kayu berpengaruh terhadap biaya produksi pemanenan kayu. Biaya produksi yang dikeluarkan perusahaan pada skenario jumlah alat ideal lebih efisien dibanding dengan biaya produksi pada skenario jumlah alat aktual, sehingga skenario jumlah alat ideal lebih menguntungkan perusahaan.
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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