Judul: Study of Deroulability in 14 Cultivars of Poplar: Analysis Cutting Force and Lathe Checks of Veneer in Micro-Lathe
Abstrak: Poplar is well known for its large wood production. Through this work, the objective of this study seeks to identify the qualities of new cultivars of poplar and classify these new cultivars in a reference quality poplar wood (by evaluating the lathe check phenomenon and measurement of cutting forces in micro-lathe). The 42 disks of 14 cultivars and three stations were conducted in 3 mm for two types of veneer, "heartwood" and "sapwood". The 14 cultivars are concerned from cultivars currently on the market of plant poplar. The micro-lathe was used to measure cutting forces. Veneer of peeling process in micro-lathe was observed using a device called SMOF for systematic and objective analysis of lathe check in the veneer. The result is shown that there no significant effect of the radial position (heartwood and sapwood) and cultivar on the cutting force (Xc/force knife vertical, Yc/force knife horizontal, Xb/force bar vertical, and Yb/force bar horizontal), depth and percentage of lathe check.
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Judul: Analisis Gaya Pemotongan dan Kualitas Permukaan Vinir Kayu Poplar (Populus spp.)
Abstrak: Fourteen new Poplar (Populus spp.) cultivars were studied in order to create the referential of Poplar quality. This report presents the results of their ability to peeling and an analysis of the quality of its products, veneers. The logs were peeling into veneers. Peeling process was differentiated by radial position, sapwood and false heartwood. Analyses of variances were used to interpret the data obtained by moisture content, percentage of fuzzy grain, the number of wave veneer, radius of wave veneer, area of wave veneer, and the cutting force consisting of Xc (vertical knife), Yc (horizontal knife), Xb (vertical bar), and Yb (horizontal bar). All of Poplar cultivar have a low specific gravity (0.30-0.38) so they were easy to peeling and have a low cutting effort. It also has sufficient moisture content. Among those cultivars, the Dvina shows a poor ability to peeling and surface quality of veneer. The radial position is significantly affected to moisture content, cutting forces, and fuzzy grain. But the values between two radial positions were not significantly different since the anatomical of Poplar was less heterogen.
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Judul: Hidrogel Poli(Asam akrilat-ko-Akrilamida)-Kitosan Hasil Iradiasi Gamma sebagai Penjerap Ion Cu(II).
Abstrak: Kitosan merupakan senyawa turunan kitin yang dapat dimodifikasi menjadi hidrogel. Hidrogel ini dapat digunakan sebagai adsorben untuk menjerap ion Cu(II). Hidrogel poli(asam akrilat-ko-akrilamida)-kitosan dapat disintesis dari asam akrilat, akrilamida, dan kitosan menggunakan teknik iradiasi gamma. Dosis yang digunakan dalam iradiasi ini sebesar 10 kGy. Komposisi kitosan yang digunakan dalam hidrogel ini sebesar 0.25 g, 0.5 g, 1.0 g, dan 1.5 g. Hidrogel terbaik yang digunakan dalam menjerap ion Cu(II) adalah hidrogel dengan komposisi kitosan terbanyak, yaitu 1.5 g. Nilai equilibrium degree of swelling (EDS) yang diperoleh sebesar 11.33 g/g dan fraksi gel mencapai 93.18%. Nilai kapasitas adsorpsi yang diperoleh dari kitosan beads dan hidrogel relatif sama, hanya berbeda pada waktu kontaknya. Adsorpsi isotermal yang terjadi pada kedua adsorben mengikuti model isotermal Freundlich.
Keyword: adsorpsi, EDS, fraksi gel, hidrogel, kitosan