Judul: Karakteristik Balok Laminasi (Glulam) Kayu Ekaliptus (Eucalyptus urophylla ST. Blake)
Abstrak: The use of wood for structural purposes requires a large dimension and long span as well as specific requirements of high strength. On the other hand, a lot of wood available today is wood from plantations with fast growing species of small diameter and generally have inferior properties such as defects content, natural durability and strength compared to wood from natural forests. One common way to get the wood to the desired dimension is the lamination technique. One of the laminate product used as a structural material is laminated timber. The aim of the study was glulam composed by three laminas thickness from eucalyptus wood. Three laminas 1cm, 1.5cm, 2cm thickness, were prepared in this study. Each laminae was tested by non destructive evaluation of deflection method to determine Modulusof Elasticity (MOE). The highest MOE of laminae was placed at the outside of glulam, then between laminas were glued by isocyanate resin. The dimension of glulam was (8 x 6 x 110) cm in thick, width, and length. The physical and mechanical properties of glulam were evaluated refering to standard JAS 234:2003. The physical properties of glulam timber of moisture content was in average value of 13.37%. The density mean of glulam timber were 0,65g/cm³ to glulam A composed by 1cm thickness of laminae, 0,63g/cm³ to glulam B composed by 1.5cm thickness of laminae, 0,56g/cm³ to glulam C composed by 2cm thickness of laminae. Delamination properties of hot and cold water were 25.2% and 4.99% for glulam A, 45.9% and 8.03% for glulam B, 73.86% and 0% for glulam C. The average value of mechanical properties Modulus of Elasticity (MOE) were 10.06x10⁴ kgf/cm² for glulam A, 7.42x10⁴ kgf/cm² for glulam B, and 5.63x10⁴ kgf/cm² for glulam C. The Modulus of Rupture (MOR) of glulam beams were 561 kgf/cm², 424 kgf/cm², and 327 kgf/cm² for glulam A, glulam B, and glulam C, respectively. Average value of shear strength properties were 98.42 kg/cm² for glulam A, 90.23 kg/cm² for glulam B, 79.01 kg/cm² for glulam C. Moisture content and delamination on cold water glulam timber were in compliance with JAS standards 234: 2003 while the delamination on heat water not fullfill to meet the standards. The MOE and MOR values the glulam timber (except MOE laminated timber with a thickness of 1.5 cm and 2 cm) were in compliance with JAS standards 234: 2003.
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Judul: Verifikasi Empiris Persamaan Lentur Statis Glued Laminated Timber (Glulam)
Abstrak: INTRODUCTION. Wood in construction is often loaded by bending moment. Since the development of wood engineering increasing, the solid wood tends to be substituted by wood’s engineering such as glulam. Glulam is usually made from some laminas. A Transformed Cross Section method has widely used to calculate the mechanical properties of glulam if each lamina’s properties are known. The method transforms each lamina based on its MOE. The longitudinal width is decreased if the MOE is lower, and increased if the MOE is higher. However MOE is a material property which is independent from the geometric property, calculated MOE based on geometric properties is not accurate. Bahtiar (2008) was developed a new methods to calculate the bending properties of glulam. The method is mathematically proven. However it would be better if empirical experiment is conducted to prove it. METHOD. Materials used in this research are 2x10x170 cm3 boards from 4 wood species, namely : Nangka (Artocarpus heterophyllus), Kapuk (Ceiba pentandra), Afrika (Maesopsis eminii), and Sengon (Paraserianthes falcataria), noted by N, R, A, and S respectively, and isosyanate adhesive to bond three layers glulam. Face and back of glulam are N and core is R, A, or S. Test of wood small clear specimen and glulam bending properties is conducted with center point loading configuration based on ASTM D143. Then the equation of load-deformation curve is built on two ways. The first way is only linier regression for data below proportional (elastic) limit; the second way is dummy variable regression which allows both linier regression for data bellow proportional limit and continued by quadratic regression for data upper proportional limit until maximum load. The empirical MOE and MOR are calculated by and equation respectively. The theoretical MOE and MOR are calculated by Bahtiar’s methods (2008). RESULTS AND DISCUSSION. The results of this research show that the average value of MOE calculated by first method for Nangka is 6,3x104 Kg/cm2, Afrika 5,9x104 Kg/cm2, Sengon 5,3x104 Kg/cm2, and Kapuk 2,7x104 Kg/cm2. Average value of MOE calculated by second method for Nangka 6,0x104 Kg/cm2, Afrika 5,6x104 Kg/cm2, Sengon 5,0x104 Kg/cm2, Kapuk 2,6x104 Kg/cm2. The MOE calculated by second method is similar with the first methods for Kapuk but lower for three other species. Average value of MOR of Nangka is 680 Kg/cm2, Afrika 490 Kg/cm2, Sengon 460 Kg/cm2, Kapuk 273 Kg/cm2. The average value of theoretical MOE for glulam N-A-N formation is 6,2x104 Kg/cm2, N-S-N is 5,8x104 Kg/cm2, and N-R-N is 5,9x104 Kg/cm2. The average value of theoretical MOR for glulam N-A-N is 617 Kg/cm2, N-S-N is 584 Kg/cm2, and N-R-N is 675 Kg /cm2. The average value of empirical MOE for glulam N-A-N is 4,6x104 Kg/cm2, N-S-N is 4,9x104 Kg/cm2, and N-R-N is 4,5x104 Kg/cm2. Meanwhile the average value of empiric MOR for glulam N-A-N is 256 Kg/cm2, N-S-N 261 Kg/cm2, N-R-N is 223 Kg/cm2. Theoretical calculation of MOE and MOR of glulam are significantly different with empiric testing result of glulam. Empirical testing shows that the average value of MOE and MOR lower than theoretic calculation. The adhesion of glulam is weaker than the
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Judul: Infeksin virus rota pada anak babi
Abstrak: Virus Rota sudah lama diduga sebagai salah satu penyebab diare pada anak babi yang baru dilahirkan. Hal ini diperkuat dengan berhasilnya Mebus dan kawan-kawan mengidentifikasi virus Rota pada kejadian diare yang ter jadi pada anak sapi yang baru dilahirkan. Infeksi virus Rota merupakan hal yang serius, kejadian yang mewabah pernah dilaporkan di Amerika Serikat, Inggris, Kanada dan Australia. Sedangkan kejadian di Indonesia yang dihubungkan dengan infeksi virus Rota belum dilaporkan. Virus Rota termasuk keluarga Reo viridea. Sesuai dengan namanya, virus Rota menyerupai roda (Rota = Wheel), mengandung asam nukleat (nucleid acid) yang berupa asam nukleat ribo (ribo nucleid acid, RNA) dan berserabut ganda (double stranded), tidak mempunyai selubung (envelop atau peplos). Hewan rentan adalah hewan yang berumur sangat muda. Selain menyerang babi, dapat pula menyerang sapi, domba, rusa, anjing, kucing, tikus, kelinci, unggas dan manusia. ...
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