Judul: Karakteristik Hasil Fumigasi Amonia Dan Daya Tahan Lapisan Finishing Pelarut Air (Waterbased Lacquer) Pada Beberapa Jenis Kayu Rakyat.
Abstrak: Wood species from community forests have a high chance to be developed of a high value-added products, particularly furniture. However, these timber forest have a less attractive appearance (pale colors and ununiforms, as well as less attractive fibers). Therefore efforts to improve the quality of its natural appearance are needed. One of the proposed method to improve the quality is ammonia fumigation method can change the color and appearance of wood becomes more attractive naturally. Therefore this method can be used for wood staining. The use of fumigation method in wood finishing process will also help in improving the effectiveness and efficiency of the finishing process. Finishing materials used should be safe for humans also having strength and good film layers. One of which is waterbased lacquer. This study aims to determine the applicability of natural wood staining by ammonia fumigation method and its effectiveness against dry wood termites (Cryptotermes cynocephalus Light). The durability of the finishing layer of waterbased lacquer to household chemicals, hot and cold test, and cross cut tests were also tested. Wood species studied were A. mangium, A. parviflorum, M. kemanga, V. pubescens, L. glauca, M. glauca, S. wallichii, and H. tiliaceus. One of most popular wood species for American and Europe consumers was also tested (the oak wood). The test results showed that ammonia fumigation method increases the aesthetic value of wood (color and pattern look natural) and increases durability of wood. In addition, visual observations on the condition of the finishing lacquer against household chemicals with intervals of 1 hour and 24 hours, and hot and cold tests indicate that the layer of waterbased lacquer have a strong resistance layer, and classified in class 10. Whereas the cross-cut test resistance showed that A. parviflorum wood of fumigation and non-fumigation classified into Grade 4B and eight other species were classified Grade 5B.
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Judul: Karakteristik Hasil Fumigasi Amonia dan Daya Tahan Lapisan Finishing Berpelarut Air Pada Beberapa Jenis Kayu dari Hutan Rakyat
Abstrak: Wood from community forest in general have a pale color, not durable, and has a less attractive appearance. Wood finishing was one of the ways to solve these problem. Ammonia fumigation was one method to change the natural wood’s color. Before marketed, furniture usually coated in order to make the better appearance and reduce the surface erosion. Waterbased wood finish used in this study did not containe toxic and ecofriendly. The purpose of study is to determine color change and durability of wood from community forest after the fumigation of dry wood termites (Cryptotermes cynocephallus Light), determine the cross cut of finishing waterbased, and to determine the durability of finishing waterbased layer for chemical household, hot, and cold. Result of this study showed that jackfriut wood, mahogany wood, teak wood, manilkara wood, and vi rasamala wood occur significant color changes while angsana wood, manii wood, and kaboril wood didn’t occur significant color change. Ammonia fumigation can increase the resistance of wood to dry wood termite attack, where the weight loss of ammonia fumigated wood was smaller than weight loss sample of unfumigated wood. Waterbased wood finished have good resistance to chemical household at one hour and 24 hours intervals and have good resistance to heat and cold. Cross cut result showed that waterbased wood finished have good adhesion at wood surface.
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Judul: Metric Solution and Electromagnetic Field Tensor of Black Hole in 4+1 Dimensional Kerr-Newman Space-Time
Abstrak: Solusi metrik Kerr-Newman merupakan solusi paling umum untuk black hole. Konstruksi metrik pada dimensi 4+1 didasarkan pada asumsi bahwa hukum-hukum fisika berlaku di semua dimensi. Tujuan penelitian ini adalah untuk mengonstruksi solusi metrik Kerr-Newman 4+1 dimensi beserta tensor medan elektromagnetiknya. Dilakukan pengambilan tebakan, reverse engineering, analisis persamaan medan Einstein, manipulasi aljabar, dan pengambilan limitasi untuk mengonstruksi dan membuktikan solusi metrik dan tensor medan elektromagnetik. Terdapat komponen-komponen off-diagonal pada tensor metrik yang diperoleh. Hal ini berkaitan dengan keberadaan parameter momentum angular a. Keberadaan parameter muatan Q dan parameter momentum angular a pada black hole Kerr-Newman mengindikasikan keberadaan parameter magnetik yang muncul pada black hole Kerr-Newman. Keberadaan parameter magnetik berkontribusi dalam membentuk medan potensial yang diajukan, dimana medan potensial tersebut terbukti benar dengan menganalisis komponen-komponen tensor medan elektromagnetik yang diperoleh., Kerr-Newman metric solution is the most common solution of black hole. Metric construction on 4+1 dimensions based on the assumption that physics law valid in all dimension. The aims of this research is to construct Kerr-Newman metric solution in 4+1 dimension and it’s electromagnetic field tensor. Guesswork, reverse engineering, analysis of Einstein’s field equation, algebraic manipulation, and limitation taking are carried out to construct and prove metric solution and electromagnetic field tensor. There is off-diagonal components in metric tensor obtained. It is related to the existence of angular momentum parameter a. The existence of charge parameter Q and angular momentum parameter a in Kerr-Newman black hole indicates the existence of magnetic parameter which appear in Kerr-Newman black hole. Magnetic parameter existence is contribute in the forming of potential field which submitted, whereby this potential field is proven correct by analyzing electromagnetic field tensor components obtained.
Keyword: Einstein field equation, Electromagnetic field tensor, Kerr-Newman metric solution, Magnetic parameter