Judul: Suatu penilaian terhadap caran pendugaan isi dolok rimba Indonesia
Abstrak: Tujuan penelitian ini ialah mencari cara-cara pendugaan isi dolok rimba yang mudah tetapi cukup cermat. Juga dari penelitian ini diharapkan keterangan tentang keberlakuan suatu tabel isi untuk berbagai jenis kayu. Jenis kayu yang diteliti adalah Meranti (Shorea spp.), Jelutung (Dyera spp.), dan Pulai (Alstonia spp.). Penelitian dilakukan di Unit Sawmill PT Way Hitam di dalam wilayah Kesatuan Pemangkuan Hutan Palembang, Sumatera Selatan. dst ...
Keyword: Rumus frustum, Benda putar, Dolok, Koefisien regresi

Judul: Perbandingan ketepatan hasil pendugaan volume sortimen kelompok meranti merah (Shorea spp.) berdasarkan beberapa rumus empiris volume sortimen : Studi kasus di areal Hak Pengusahaan Hutan PT. Inhutani III Sampit, Kalimantan Tengah
Abstrak: Penggunaan kayu dalan bentuk dolok terus meningkat, sehingga keakuratan dalam menduga volumenya menjadi bertambah penting. Mengingat pengukuran volume secara langsung dengan xylometer untuk kepentingan praktis di lapangan tidak memungkinkan, maka penggunaan rumus-rumus empiris sangat penting. Tujuan penelitian ini adalah mendapatkan rumus empiris yang paling baik untuk menduga volume dolok jenis Meranti Merah (Shorea spp.) dipandang dari segi ketelitian hasil dan kepraktisan dalam penggunaannya. Pengambilan data di lapangan dilakukan dengan cara purpossive pada sortimen-sortimen tertentu dari berbagai ukuran dan kualita tertentu, yang meliputi pengukuran diameter, panjang dan waktu kerja. Sedangkan data penunjang yang mencakup data dasar kualitas diambil dari industri di lingkungan PT. INHUTANI III Sampit, Kalimantan Tengah. Dalam penentuan rumus terpilih, digunakan kriteria tingkat ketepatan, ketelitian dan kepraktisan dalam peng- gunaannya. Tingkat ketepatan setiap rumus penduga volume sortimen diukur oleh simpangan rata-rata (SR), simpangan agregat (SA) dan bias, sedangkan tingkat ketelitian diukur oleh Galat baku (Se) dan selang toleransi. Untuk mengetahui hubungan antara kualitas sortimen dengan ketepatan dipergunakan rancangan percobaan faktorial, sedangkan rancangan acak lengkap dipakai untuk menganalisis waktu kerja dari setiap rumus.
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Judul: Bioelectricity Production from Citrobacter freundii GBH253 and Chlorella pyrenoidosa on Microbial Fuel Cell Anode with Different Carbon Sources
Abstrak: Microbial Fuel Cell (MFC) development has significantly increased from various aspects to get higher and more stable electricity. Developing MFC on microorganism aspect is very important because it plays a crucial role in the MFC system. C. freundii GBH253 is one of the potential exoelectrogen bacterium that could be developed for the MFC system. Integrating C. freundii GBH253 and electricity-producing microalgae, such as C. pyrenoidosa, in the anode of MFC could get more stable and higher electricity. In this study, C. freundii GBH253 and C. pyrenoidosa were coupled to produce electricity from different substrates. C. freundii GBH253 and C. pyrenoidosa were tested on three different media types before being tested on MFC. They were also examined for the co-cultivation test to determine the symbiotic relationship between the two microorganisms. The MFC test was conducted using the Randomized Block Design Factorial and the Tukey test to see significant differences from each treatment. The parameters observed in this study were voltage, power density, Chemical Oxygen Demand (COD), Coulombic Efficiency (CE), pH, and volatile fatty acid (VFA). C. freundii GBH253 cannot grow on microalgae medium, while C. pyrenoidosa could grow on bacterial medium and a mixture of bacterium and microalgae media. The bacterium gained benefit from co-culture with microalgae. In the MFC test, electricity was generated in all treatments, which bacterium + microalgae with acetate treatment could generate power density up to 211,97 mW/m2 and the most stable compared to others. Production of electricity in bacterium-microalgae combination dominated by the bacterium; hence, microalgae still help bacterium by producing electricity and raised the COD value. The pH value of all treatments was higher than the initial pH. Acetate and phenol were VFA produced in all treatments, whereas butyric acid and propionic acid were found in some treatments. Pearson correlation showed that some VFA highly correlated with power density.
Keyword: Chlorella pyrenoidosa, Substrate, Microbial Fuel Cell, Electricity Producing Microalgae, Volatile Fatty Acid, Citrobacter freundii