Asian Science Citation Index is committed to provide an authoritative, trusted and significant information by the coverage of the most important and influential journals to meet the needs of the global scientific community.  
ASCI Database
308-Lasani Town,
Sargodha Road,
Faisalabad, Pakistan
Fax: +92-41-8815544
Contact Via Web
Suggest a Journal
 
Articles by Atmawi Darwis
Total Records ( 5 ) for Atmawi Darwis
  Atmawi Darwis , Dodik Ridho Nurrochmat , Muh. Yusram Massijaya , Naresworo Nugroho , Eka Mulya Alamsyah , Effendi Tri Bahtiar and Rahmat Safe`i
  Palm oil tree (Elaeis guineensis Jacq.) is a plant species which belong to monocotyledons. The Oil Palm Trunk (OPT) is composed of vascular bundles and parenchyma as ground tissue which determine the properties of the wood. This study was conducted to find out the effect of the vascular bundles toward the density and mechanical properties of OPT in vertical and horizontal direction. The results showed that in horizontal position (outer to the center zone of OPT), the greater number of the vascular bundles contained in trunk made the density value and the mechanical properties greater but in vertical position showed otherwise. The number of vascular bundles is not the only factor that determines the density and mechanical properties of OPT. The top section of OPT has a lower density and mechanical properties than the bottom even though the number of vascular bundles can be greater. This happens because the vascular bundles in the top are composed by the younger cells than the bottom.
  Atmawi Darwis , Ihak Sumardi , Yoyo Suhaya and Sopandi Sunarya
  Background and Objective: Bamboo culm was composed of internodes and nodes. Anatomically, bamboo culm was composed of vascular bundles (VB) and parenchymal base tissue. The purpose of this study was to determine the morphology features of culm and VB of bamboo Gigantochloa apus. Materials and Methods: The sample was taken from each internode of bamboo. The morphology of bamboo culm was determined by measuring the length, diameter and wall thickness. VB characterization was obtained through observation on each internode of bamboo culm. Results: The results showed that bamboo culm had internode length and inner diameter that varied from the bottom, increased at a certain height then decreased toward the top. The size of outer diameter and wall thickness of bamboo culm tended to decrease from bottom to top. VB on each internode was spread unevenly where the distance between VB looked more widened from the outer layer to the inner layer. VB distribution in the cross section had a crossing pattern (alternate). VB varied in shape and size from outer layer to inner layer of bamboo culm. The VB type on an internode of G. apus bamboo culm also showed variations where there was VB in type III only and some also were in type (III and IV) in each internode. Conclusion: The morphology of the bamboo culm was influenced by the morphology of young shoot. VB of bamboo G. apus spread unevenly with varying sizes, shapes and type from the outer layer to the inner layer.
  Effendi Tri Bahtiar and Atmawi Darwis
  Sigmoid curve was well known as a general curve to fit the growth behavior of cell, organism, or population in accordance with limitation of genetic, environmental capacity and density in their habitat. Unfortunately, many growth behaviors did not follow the basic sigmoid curve because the prerequisite assumptions were not fulfilled by actual condition. In this study, linear and nonlinear function were used to modify the exponential curve become a new growth curve which could be used in more general cases than available model nowadays. Linear modification developed basic sigmoid curve. Nonlinear functions were proposed to modify the exponential curve in this study were named after: Second order polynomial (quadratic), logarithm and second order logarithm. Basic sigmoid curve and logarithm modification on exponential curve resulted curve which always had one asymptote line so it was suitable for fitting the fiber length data at every growth ring if the samples were completely made from juvenile and mature period. If the samples came from the juvenile period alone or the researcher had not certainly sure yet, quadratic or second order logarithm modification were highly recommended to be used because those equations could result two, one, or none asymptote line. Second order logarithm was generally become the best one among others. Mathematical curve fitting on fiber length growth in this study was successfully pointed the transitional age of juvenile/mature period of Teakwood with high coefficient of determination and low standard deviation. Based on recommended mathematical method, the transitional age of Teakwood was 9-12 years old. It was more precise than visual assessment conducted by 30 undergraduate students in wood science and technology class in Bogor Agricultural University which resulted 7-15 years old. The mathematical method reduced the subjectivity and variability compared to visual assessment.
  Eka Mulya Alamsyah , Ihak Sumardi , Sutrisno , Atmawi Darwis and Yoyo Suhaya
  Background and Objectives: Facing the increasing of wood demand from community forest for timber industries has been urged some Indonesian wood researcher to handle and investigate the suitability of wood species with adequate adhesive to produce the best quality of wood bonded products that could increased the value of the wood from those community forest. The purpose of this study was to utilize and find out the best bond quality of surian wood as a new raw material for laminated wood compared to the commonly wood species used, namely sengon. Material and Methods: Two-ply lamination was produced under room temperature condition. Each lamination were bonded by urea formaldehyde (UF), polyvinyl acetate (PVAc), resorcinol formaldehyde (RF) and aqueous polymer isocyanate (API) resin adhesives at spread rate of 300, 200, 250 and 250 g m–2, respectively, then pressurized at 10 kgf m–2 for 24 h. After conditioned for a week at room temperature of 20°C and 65% humidity, it was immediately followed by physical and mechanical test under JAS standard. Results: The highest bond shear strength with the highest wood failure percentage was the laminated wood of surian bonded with API adhesive rather than PVAc, UF and RF adhesives. It showed that the best bond quality of laminated wood of surian was obtained for laminated wood bonded with API adhesive. Conclusion: Surian wood with the good bond quality than sengon wood has the high opportunity to utilize in Indonesian timber industries for the future, especially for producing the laminated wood bonded with API adhesive.
  Tati Karliati , Ihak Sumardi , Atmawi Darwis and Alfi Rumidatul
  Background and Objectives: Adhesives are one of the most important ingredients in plywood industry. Black liquor (BL), a liquid comprising waste from the pulping process, was used to reduce adhesive consumption in plywood production. The characteristics of BL and properties of phenol-formaldehyde-based black liquor as an adhesive on the performance of jabon (Anthocephalus cadamba Miq.) plywood were investigated. Materials and Methods: Adhesive mixes were prepared using phenol-formaldehyde (PF) with the seven kraft BL-based adhesive added (0, 5, 10, 15, 20, 25 and 30% (w/w). Three-ply panels were produced at glue spread of 180 g cm–2 , then pressurized at 10 kg f cm–2 at a temperature of 140°C for four minutes (PF-BL plywood). The physical and mechanical properties of PF-BL plywood were analyzed according to Standard Nasional Indonesia (SNI) and Japanese Agricultural Standard (JAS). Results: The crystallinity of BL was 25.88%, mean while methanethiol (CAS) mercaptomethane, ethanedioic acid (CAS) oxalic acid, methanethiobis-(CAS) 2-thiapropane, phenol 2-methoxy-CAS guaiacol, phenol 2,6-dimethoxy-CAS 2,6 dimethoxy phenol were the dominant of chemical components in BL. Jabon plywood bonding with PF-BLadhesiveup to 30% of BL addition, met the SNI and JAS standards. The best treatment for PF-BL plywood was reached at 15% of BL addition. Conclusion: Up to 30% BL addition can be used to reduce PF resin in order to produce PF based plywood. BL was a potential material for decreasing the use of PF-based adhesive for plywood.
 
 
 
Copyright   |   Desclaimer   |    Privacy Policy   |   Browsers   |   Accessibility