Judul: Pengkajian kemoreaksi CaO untuk pengeringan kayu lunak (Paraserianthes falcataria)
Abstrak: The objective of this experiment were to measure how many moisture can be absorbed by CaO on some interval time, and to observe the physical change of the woods. Each six logs of softwood (Paraserianthes falcataria) were put in drum which fill by quikclime, then drums are closed. Wood and quicklime taken from the wood in 10 days for first wood, in 20 days for second wood, in 30 days for third wood, and in 40 days for fourth wood, fifth wood, and sixth wood. The results from this experiment were the loss of moisture of wood from 10th days was 13.9%, from 20th days was 21.9%, from 30th days was 20.5%, and from 40th days was 24.2%. The loss of moisture content from radial section bigger than cross section. The physical change from the wood happened in cross section, where there were crack in the middle. The gravitational force also influence the distribution of moisture content that absorbed by quicklime, where the bottom part have the bigger moisture content than the up part of radial section.
Keyword: Wood, Quicklime, Moisture conten, Bogor Agricultural University, Institut Pertanian Bogor, IPB

Judul: The Fire Resistance and Biodeterioration of Maesopsis eminii Wood Impregnated With Boric Acid and Vegetable Oils
Abstrak: Kayu cepat tumbuh saat ini banyak dibudidayakan masyarakat dan dimanfaatkan sebagai bahan furniture, bahan bangunan, atau penggunaan lainnya. Kayu manii (Maesopsiss eminii Engl.) merupakan jenis cepat tumbuh yang memiliki kelas awet rendah (IV) sehingga memerlukan teknologi peningkatan ketahan dari organisme perusak terutama yang ramah lingkungan. Penelitian ini bertujuan untuk menguji efektivitas perlakuan kombinasi asam borat dengan minyak nabati dan pemanasan dalam ketahanan kayu Maesopsis eminii dari api, rayap, dan jamur di lapangan. Proses impregnasi asam borat dan minyak nabati (mimba, nyamplung, dan kemiri) dilakukan secara bertingkat dalam tangki dengan tekanan 7 kg cm-2 selama 4 jam. Selanjutnya dilakukan pemanasan dalam oven Memmert pada suhu 60 ºC, 120 ºC dan 180 ºC selama 4 jam. Pengujian yang dilakukan meliputi uji ketahanan api, uji lapang biodeteriorasi menyentuh dan tidak menyentuh tanah. Perlakuan asam borat pada umumnya meningkatkan ketahanan kayu dari pembakaran terutama yang dikombinasikan dengan minyak kemiri dan pemanasan 60 °C. Perlakuan minyak nabati (mimba, nyamplung, dan kemiri) meningkatkan ketahanan kayu dari biodeteriorasi di dalam dan di atas permukaan tanah. Pada umumnya kayu mengalami penurunan nilai kecerahan (L) (menjadi lebih gelap) setelah pemaparan alami., Fast-growing species are widely cultivated by the community and used for furniture, building materials, or other uses. Manii wood (Maesopsiss eminii Engl.) is a fast growing species that has a low durability, class IV. So it requires technology to increase its resistance from, degrading organisms, especially that is environmentally friendly. This study aimed to examine the effectiveness of boric acid, vegetable oil and heating on the resistance of Maesopsis eminii wood against fire, termites and fungi in the field. The impregnation of boric acid and vegetable oils (neem, tamanu, and candlenut) were carried out in a tank with a pressure of 7 kg cm-2 for 4 hours. Then the wood samples were heated in a Memmert oven at 60 ºC, 120 ºC and 180 ºC for 4 hours. The following tests included fire resistance, above-ground and ground-contact biodeterioration field tests were carried out. Boric acid treatment generally increased the resistance of wood against fire, especially in combination with candlenut oil and heating at 60 °C. Treatment of vegetable oils (neem, tamanu, and candlenut) increased the resistance of wood against biodeterioration in above-ground and ground-contact field tests. In general, brightness value (L) of wood decreased (becoming darker) after natural exposure.
Keyword: color, fast growing wood, heating, modification, weight loss

Judul: igenvalues and Eigenvectors of Tridiagonal Matrix with Non Constant and Recurrent Diagonal Entries.
Abstrak: Matriks tridiagonal adalah suatu matriks yang mempunyai entri-entri bernilai nol kecuali pada diagonal utama, di bawah diagonal utama (subdiagonal) dan di atas diagonal utama (superdiagonal). Entri pada diagonal utama tidak konstan dan berulang. Setiap entri pada matriks tridiagonal ini adalah bilangan kompleks. Dalam karya ilmiah ini, akan dibuktikan 3 teorema untuk menentukan nilai eigen dengan 2 kasus dan 1 teorema untuk menentukan vektor eigen. Teorema pertama menentukan polinomial karakteristik dari matriks tridiagonal. Polinomial karakteristik dari matriks tridiagonal tersebut digunakan untuk menentukan nilai eigen pada teorema kedua dan ketiga serta menentukan vektor eigen pada teorema keempat
Keyword: