Judul: Timber Hauling Productivity of Rasamala and Puspa Wood with Trailered Off-road Car in RPH Takokak KPH Sukabumi
Abstrak: Pengangkutan kayu bertujuan untuk memunculkan nilai ekonomis dari kayu karena telah diterima oleh industri, konsumen ataupun distributor. Kayu di Resort Pemangkuan Hutan (RPH) Takokak diangkut dengan menggunakan mobil off-road modifikasi dan diberi tambahan trailer. Penelitian ini bertujuan menganalisis produktivitas dari kegiatan pengangkutan menggunakan mobil off-road yang telah dimodifikasi dan diberi tambahan trailer, serta menganalisis tingkat risiko kecelakaan kerja dalam kegiatan pengangkutan kayu rasamala dan puspa di RPH Takokak, Kesatuan Pemangkuan Hutan (KPH) Sukabumi. Hasil penelitian menunjukkan penggunaan mobil off-road ber-trailer di RPH Takokak menghasilkan produktivitas efektif sebesar 2,39 m3/jam dan produktivitas aktual sebesar 1,72 m3/jam. Persentase tingkat risiko keselamatan kerja pengangkutan di RPH Takokak menunjukkan 26,1% dari 23 sub-aktivitas termasuk kategori low risk, 65,2% moderate risk, 8,7% high risk dan 4,3% extreme. Manajemen risiko dilaksanakan dengan penaatan penggunaan Alat Pelindung Diri (APD), kontrol administratif, mengisolasi para pekerja dari sumber bahaya, serta menyubstitusi sumber bahaya., Timber hauling is aimed at bringing out the economic value of wood, as it has been accepted by industries, consumers, or distributors. The logs at the Takokak Forest Management Resort (RPH) are carried out using modified off-road vehicles with additional trailers. This research aims to analyze the productivity of timber hauling activities using modified off-road vehicles with additional trailers and to assess the level of safety hazards in the hauling activities of Rasamala and Puspa wood in the Takokak RPH, Sukabumi Forest Management Unit (KPH). The research results indicate that the use of off-road vehicles with trailers at RPH Takokak yields effective productivity of 2.39 m3/hour and actual productivity of 1.72 m3/hour. The percentage of safety risk in timber hauling at RPH Takokak shows 26.1% of the 23 sub-activities falling into the low-risk category, 65.2% moderate risk, 8.7% high risk, and 4.3% extreme risk. Risk management is implemented through the compliance with Personal Protective Equipment (PPE) usage, administrative controls, isolating workers from hazards, and substituting hazards.
Keyword: pengangkutan, produktivitas, mobil off-road, rasamala, puspa, job safety analysis, hauling, productivity, off-road cars

Judul: Productivity of Skidding Firewood Using a Motor Engkrek In KPH Bandung Utara
Abstrak: Salah satu kegiatan penting dalam pemanenan kayu adalah kegiatan memindahkan kayu dari tempat penebangan ke tempat pengumpulan kayu (TPn) atau biasa disebut penyaradan. Penyaradan kayu bakar di KPH Bandung Utara dilakukan secara mekanis menggunakan bantuan motor engkrek. Tujuan penelitian ini adalah mengetahui produktivitas, biaya penyardan kayu bakar menggunakan motor engkrek serta pengaruh kemiringan lereng, jarak sarad, dan volume kayu yang disarad terhadap biaya dan produktivitas dan tingkat risiko kecelakaan kerja pada kegiatan penyaradan. Data primer didapatkan dari pengamatan langsung serta data sekunder didapatkan melalui studi pustaka. Hasil produktivitas pada topografi landai berdasarkan waktu efektif dan aktual sebesar 0,77 m3/jam dan 0,52 m3/jam, sedangkan pada topografi agak curam sebesar 0,56 m3/jam dan 0,37 m3/jam. Biaya penyardan pada topografi landai sebesar Rp 16.936/m3, sedangkan pada topografi agak curam sebesar Rp 20.680/m3. Produktivitas dan biaya penyaradan dipengaruhi oleh kemiringan lereng, jarak, dan volume kayu yang disarad. Analisis risiko menunjukkan pada kegiatan penyaradan terdapat 1 risiko tinggi, 3 risiko sedang, dan 2 risiko rendah., One of the important activities in timber harvesting is the activity of moving wood from the logging site to the wood collection point (TPn) or commonly called skidding. Skidding of firewood at KPH Bandung Utara was carried out mechanically using the help of a motor engkrek. The purpose of this study was to determine the productivity, the cost of extracting firewood using a motor engkrek and the effect of slope, skidding distance, and the volume of skidded wood on the cost and productivity and the risk assesment in skidding activities. Primary data obtained from direct observation and secondary data obtained through interviews. Productivity results on sloping topography based on effective and actual time are 0,77 m3/hour and 0,52 m3/hour, while on steep topography are 0,56 m3/hour and 0,37 m3/hour. The cost of dredging on a sloping topography is Rp 16.936/m3, while on a steep topography it is Rp 20.680/m3. The productivity and cost of skidding are affected by the slope, distance, and volume of skidded wood. The risk analysis shows that in the skidding activity there is 1 high risk, 3 moderate risk, and 2 low risk.
Keyword: cost, productivity, risk, skidding

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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