Judul: Ekstraktif Kulit Kayu Samak (Syzygium inophyllum DC.) sebagai Pewarna Alami Kayu.
Abstrak: Natural color of the wood is one of the characteristics that make certain types of wood very attractive aesthetically and has a high economic value. Staining is one of the finishing processes on wooden products, to obtain more attractive colors. Nowadays, the use of natural dyes in the handicraft and furniture industry is increasing. The aim of this research is to produce natural dyes from samak bark and to test the quality of the color, the physical properties, the mechanical properties, and the resistance to wood destroying organism of stained jabon wood. Natural dyes was obtained by extracting samak bark (S. inophyllum) using water , ethanol and water-ethanol mixture (3:1, 1:1 and 1:3 v/v) solvent. The staining process was applied to jabon wood by hot soaking for 3 hours and cold soaking for 72 hours, respectively.. The stained jabon wood performance were evaluated including the color leaching test in hot water, cold water, teepol soap solution, and the color change by acid solution. The color leaching assessed by determination of color changes using the CIELab method, FTIR analysis. Staining of jabon wood with samak bark extract obtained from water - ethanol ( (3:1 v/v) extraction showed a good coloring performance and high color stability (less leaching ability) . In addition, the resistance of stained jabon wood to biodegradation (termites and fungi) increases significantly. . The catechol as the main component in the extract seems to be compound played, not only, as a natural dye but also as an antitermite and fungi’s growth inhibitor. However, there was not effect of extracts to the physical properties (specific gravity and density) and mechanicals properties (MOE, MOR and hardness) of the stained wood.
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Judul: Color and Wettability of Impregnated Jabon and Ganitri Wood by MFFA with Nano-SiO2
Abstrak: Kayu cepat tumbuh memiliki siklus tebang yang pendek sekitar 6-7 tahun, namun memiliki karakteristik kayu yang inferior, yaitu berat jenis, kekuatan dan keawetan yang rendah. Penelitian ini bertujuan untuk menganalisis pengaruh impregnasi MFFA dan nano-SiO2 terhadap perubahan warna dan nilai keterbasahan pada kayu jabon (Anthocephalus cadamba) dan ganitri (Elaeocarpus sphaericus). Perlakuan terdiri dari 2 faktor yaitu larutan impregnasi dan jenis kayu. Perlakuan larutan impregnasi terdiri dari 3 taraf yaitu kontrol (tanpa perlakuan), MFFA, dan MFFA nano-SiO2 0,5%. Proses impregnasi dilakukan dengan memberikan vakum 0,5 bar selama 60 menit, dilanjutkan dengan memberikan tekanan 2 bar selama 120 menit. Hasil penelitian menunjukkan bahwa perubahan warna (ΔE) yang besar terjadi pada kayu jabon dan ganitri akibat perlakuan MFFA dan MFFA nano-SiO2 0,5% jika dibandingkan dengan kontrol. Penambahan nano-SiO2 pada larutan MFFA dapat meningkatkan kecerahan warna (menurunkan ΔE) pada kedua jenis kayu. Perlakuan MFFA dan MFFA nano-SiO2 0,5% juga memberikan pengaruh yang nyata terhadap nilai sudut kontak dan nilai K. Perlakuan paling optimum untuk keterbasahan kayu jabon dan ganitri diperoleh dengan pemberian perlakuan MFFA nano-SiO2., Fast-growing wood which has a short cutting cycle of about 6-7 years, usually has inferior wood characteristics, namely low density, strength and durability. This study aim was to analyze the effect of MFFA and nano-SiO2 impregnation on discoloration and wettability values of jabon (Anthocephalus cadamba) and ganitri (Elaeocarpus sphaericus) wood. The treatments were the impregnation solution and the wood species. The impregnation solution treatments were consisted of 3 levels, namely control (water treated), MFFA, and MFFA nano-SiO2 0.5%. The impregnation process was initiated by applying a vacuum of 0.5 bar for 60 minutes, followed by applying a pressure of 2 bars for 120 minutes. The results showed that large discoloration (ΔE) occurred in jabon wood and ganitri after being treated by 0.5% MFFA and MFFA nano-SiO2. The addition of nano-SiO2 to the MFFA solution can increase the color brightness (decrease ΔE) in both wood species. The treatment of MFFA and MFFA nano-SiO2 0.5% also had a significant effect on the contact angle and the K values. The optimum treatment for the wettability of jabon and ganitri wood was MFFA nano-SiO2.
Keyword: Discoloration, Impregnation, MFFA, Nano-SiO2, Wettability

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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