Your search resulted in 11 documents.
The present status of wooden catamarans of the Indian Coast
1997 - IRG/WP 97-10231
Catamarans (a.k.a. kattumarams) are the most widely used fishing craft in India, and hundreds of thousands of poor, traditional fishermen depend on these vessels for their livelihood that are almost made entirely of wood. In recent years, acute shortages and phenomenal increases in prices of timber species used in catamaran fabrication have been reported, causing great hardship to the user community. Further, the patterns of usage are based on age-old practices and not on scientific lines, resulting in significant waste of timber during fabrication and use. This paper, while highlighting the importance and benefit of usage of catamarans in the Indian context, stresses the need for introduction of steps to ameliorate the current losses, and outlines the various research and development efforts undertaken in this direction. Of special importance in this context is the on-going World Bank-aided program on catamarans, being handled at the Institute of Wood Science and Technology, Bangalore.
K S Rao
Some recent studies on the marine wood-borers of the west coast of India
1982 - IRG/WP 486
Occurrence and distribution of marine wood-borers along the west coast of India from Mangalore to Kandla are presented together with the distribution pattern of all the molluscan and crustacean wood-borers so far reported from India coasts. The survey, conducted for the first time along this coast, revealed the presence of 14 species of Teredinidae, 2 species of Pholadidae, 3 species and one variety of Sphaeromati and 1 species of Limnoriidae. It includes 3 new records (Bankia nordi Moll, Nototeredo edax (Hedley) and Teredothyra smithi (Bartsch) from the west coast and 3 new records (Teredothyra matocotana (Bartsch), Lyrodus massa (Lamy) and Martesia sp.) from Indian waters. Distribution of several species like Nausitora hedlevi Schepman, Teredo clappi Bartsch, Sphaeroma terebrans Bate, Sphaeroma annandalei Stebbing and Sphaeroma annandalei travancorensis Pillai has been considerably extended further north along the west coast of India.
L N Santhakumaran
Leaching of CCA from Bombax ceiba catamarans in operation for 15 years
2002 - IRG/WP 02-50191
Core samples of wood at random were collected from all the timber pieces of each of the three catamarans made of CCA treated logs of Bombax ceiba put to continuous service for the last 15 years at the Lawson's Bay fishing village, Visakhapatnam. The samples were dried to constant weight, powdered, digested and analyzed for the residual salts of the preservative. The residual content of CCA was found to be 6.90, 6.24 and 7.43 kg/m3 in CAT I, II and III, respectively. The values for individual components of arsenic, copper and chrome were 0.24 to 0.34 kg/m3, 3.34 to 4.37 kg/m3 and 2.66 to 3.03 kg/m3, respectively. Making use of the initial absorptions of the preservative determined at the time of treatment and the residual contents estimated now, the leaching rates of CCA and it's components were calculated. While the annual leaching rate of CCA was observed to be 1.22 kg/m3 (CAT I), 0.81 kg/m3 (CAT II) and 0.83 kg/m3 (CAT III), at elemental level, it was found to be 0.05, 0.04 and 0.05 kg/m3 in the case of arsenic, 0.15, 0.10 and 0.09 kg/m3 in the case of copper and 0.20, 0.12 and 0.14 kg/m3 in the case of chromium for CAT I, II and III, respectively. The results thus indicate that while about 2/3rd the initial amount of CCA had been leached out of the catamarans during the last 15 years, still 1/3rd the amount is present in the logs. Thus, the preservative left out in the catamarans appears to be sufficient to offer protection to the craft for a good number of years to come.
V Kuppusamy, M Balaji, M V Rao, K S Rao
Performance of Copper-Chrome-Arsenic (CCA) and Copper-Chrome-Boric (CCB) treated panels of Bombax ceiba and Paraserianthus falcataria against bio-deterioration at Krishnapatnam harbour, east coast of India
2003 - IRG/WP 03-30310
Results of investigations on the durability of light weight timber species (Specific gravity below 0.4) i.e., Bombax ceiba and Paraserianthus falcataria in treated and untreated condition conducted at Krishnapatnam harbour (Lat 13o28’ to 13o59’ N; Long: 80o10’ to 80o16’E) along the east coast of India are reported in the paper. Exposure trails were conducted with panels (Size: 30 x 3.8 x 3.8 cm.) treated with CCA (Copper–Chrome–Arsenic) and CCB (Copper-Chrome-Borate) at four retention levels (8, 16, 24, and 32 kg/m3), for a period 3 years from August, 1997 to July, 2000. Control panels of both the species were heavily attacked by shipworms and pholads and rejected in a period of 3 months. On these, panels, shipworms attained maximum growth of 2.3 cm. and pholads 1.4 cm. On these panels. borer species identified were: Martesia striata, M. nairi, Teredo furcifera, T. fulleri, Lyrodus pedicellatus, and Bankia campanellata. Timber panels treated with CCA at lower loadings (8 and 16 kg/3) had greater number of shipworms (>200) than pholads. Shipworms and Pholads attained maximum growth of 2.6 and 1.8 cm respectively. Panels treated with higher loadings (24 and 32 Kg/m3) had more pholads (>150) than shipworms. Pholads and shipworms attained maximum growth of 3.1 and 6.8 cm respectively on these panels. The CCB treated panels of lower loadings also had heavier shipworms (>300) that attained maximum growth of 16 cm, whereas, pholads attained a maximum of 2.2 cm. On higher loadings of CCB treated panels, pholads intensity was observed to be greater and attained a growth of 3.4 cm while shipworm attained 1.9 cm. Overall, shipworm intensity was found to be greater on CCA and CCB panels with lower retentions (8 and 16 Kg/m3), whereas penetration was not deep on higher loadings (24 and 32 Kg/m3). CCA treated panels with lower loadings (8 and 16 Kg/m3) were found to be better than those of lower loadings of CCB. However, at higher loadings (24 and 32 Kg/m3) variations were not significant.
B Tarakanadha, N R Raveendra Prasad, K S Rao
Heat treatment of less-valuable Nigerian-grown Ceiba pentandra wood for improved properties
2006 - IRG/WP 06-40332
The hardwood Ceiba pentandra locally known as “ araba “ in Nigeria is rarely used for structural and construction works due to its high dimensional instability, low strength and durability values. Samples (10 x 10 x 150mm) were removed from four green boards (25 x 200 x 3000mm) of this species originating from a natural forest stand in Nigeria and subjected to 2-hour heat treatment at 160°C and 220°C. Heat treatment reduced swelling, hygroscopicity and swelling intensity of Ceiba pentandra wood with the reductions being generally higher in the 220°C treatment than the 160°C treatment. The reductions constitute improvements in these properties. These improvement in properties have the potential to increase the market value of this species through wider acceptability for various purposes hitherto considered impossible. This however is subject to further investigations on the effects on durability and strength properties which are other key features in the choice of wood for various purposes.
Non-pressure preservation technique of five less durable timber species – Kadam (Anthocephalus cadamba), Shimul (Bombax ceiba), Pithalu (Trewia nudiflora), Am (Mangifera indica) and Boroi (Ziziphus jujube) of Bangladesh
2006 - IRG/WP 06-40322
Wood is a versatile renewable resource, which has been extensively used as a reliable construction material as well in furniture ever since the beginning of civilization. The Major disadvantage of wood is its susceptibility to biodeterioration by fungi, insects and bacteria. In tropical countries like Bangladesh, fungi is the most significant of these biodeterioration agents. Kadam (Anthocephalus cadamba), Shimul (Bombax ceiba), Pithalu (Trewia nudiflora), Am (Magnifera indica), and Boroi (Ziziphus jujube) are five, local and available, useful but less durable timber species of Bangladesh. The heartwood of these timber species is more or less resistant to decay and insects, but sapwood faces quick deterioration while exposed to moisture and wood enemies. On the other hand, wood can be protected from attacks from these enemies with the appropriate preservative treatment, by reducing or changing the form of its food toxic to wood enemies. So, appropriate preservative treatment is required to increase the durability of these timber species. The study of chemical preservative treatment of these five timber species has been undertaken using a mixture of Chromate-copper-boron (CCB) at 2:2:1 ratio with four different concentrations of 4, 6, 8 and 10% and different treatment durations of 8, 16 and 24 hours by non-pressure dipping method. It has been observed that Pithalu showed comparatively higher preservative retention than other four species, which indicates that Pithalu is a permeable and diffuse specie for dipping method. A preservative penetration test provided the information that air dried wood samples using 10% preservative concentration with 8 hour and 24 hours duration of dipping gave the best result for copper, while 10% preservative concentration with 24 hours duration used on green wood has shown the best result for boron penetration. The major physical properties of wood viz., moisture content, density and shrinkage have also been studied. Anthocephalus cadamba showed a lower density, while Ziziphus jujube had a higher density. Bombax ceiba and Trewia nudiflora are very close to Anthocephalus cadamba and Magnifera indica is very close to Ziziphus jujube with respect to the moisture content. Bombax ceiba, Trewia nudiflora and Magnifera indica showed all moderate positions with respect to density.
G N M Ilias, A H Kabir, F Begum, M F Alam
Assessment of the ease of preservative treatment in the less-valuable Nigerian-grown Ceiba pentandra wood
2006 - IRG/WP 06-40330
The hardwood Ceiba pentandra locally known as “araba“ in Nigeria is rarely used for structural and construction works due to its high dimensional instability, low strength and durability values. Samples (25 x 50 x 600mm) were removed from four green boards (25 x 200 x 3000mm) of this species originating from a natural forest stand in Nigeria. The sapwood and heartwood were differentiated by means of colour. Samples were dried at 60oC in a kiln for five days to a final moisture content of 12%. Specimens were then machined and planed to final dimensions of 20 x 20 x 305mm and 20 x 20 x 50mm. Five faces in each specimen were sealed using an epoxy resin (West Systems, UK) to allow treatment in the axial, radial and tangential directions to be assessed. After sealing, the samples were conditioned at a temperature of 20oC and 65% relative humidity and weighed to the nearest milligram. Preservative treatment was carried out by the pressure treatment method using 5% copper sulphate solution. After preservative impregnation, the specimens were conditioned at a temperature of 20°C and 65% relative humidity and were thereafter sprayed with chromazurol. The dark blue colour shown by all the specimens after the chromazurol spraying indicates the presence of copper and hence confirming that impregnation took place in all the specimens. The photographs of the sections cut through the specimens showed that the preservative had penetrated along the lengths of the sapwood and heartwood stakes with penetration exceeding 300mm. Radial and tangential penetrations were also complete for both the heartwood and sapwood. The results of the T-test analysis of differences in mean preservative uptake show that there are no significant differences in the rate of uptake between heartwood and sapwood in all the three directions. Using the degree of preservative penetration, both the heartwood and sapwood were found to be in 2+ treatability classes according to prCEN/TR 14734, the ease of preservative treatment in this species indicates the possibility of improving its durability rating and thus invariably increases in market value expected.
L Awoyemi, A J Pitman
Effect of borax-boric acid Treatment of simul (Bombax ceiba) Veneers on Glue-Bond Quality of Plywood
2010 - IRG/WP 10-40525
The glue-bond quality of plywood made of treated simul (Bombax ceiba) veneers was investigated. The veneers were treated with cold and hot water solution of borax-boric acid (BB) of different concentrations and treatment durations. The plywoods were made at three different pressures in hot press using urea formaldehyde glue. The glue-bond strength of untreated plywood in dry shear-test was found to be 2.17 and 2.29 N/mm2 made at 1.05 and 1.40 N/mm2 pressure respectively. It was observed that the values of load at failure of treated plywood in dry shear-test gradually decreased with the increasing treatment duration and concentration of solution. Comparison of the bond strength of untreated plywood with the treated ones made with urea formaldehyde glue showed that all the treatment combinations lowered the bond quality. It was also found that 10% BB solution and highest treatment duration (3 for cold water days and 60 minutes for hot water) lowered the bond strength of the plywood which met ‘B-grading’ requirement. However, the values of glue bond strength in all other BB treated plywood met ‘A-grading’ requirement for gluing. It may be due to the highest percentage of chemical deposition within the cell wall structure lowered the bond quality. For all the treatments, low values of shear strength were observed in plywood made of hot water-treated veneer compared to that of cold water.
K Akhter, Md Abul Hashem, S Akhter
Preservative Treatment of simul (Bombax ceiba) Veneers with Hot and Cold Water Solution of borax-boric acid by Soaking Process
2010 - IRG/WP 10-40528
Veneers of simul (Bombax ceiba) were treated with different concentrations of water- borne preservatives borax-boric acid (BB) by soaking process for different time periods. In the case of hot water treatment, it was found that the average retention of preservative chemicals increased gradually with the increasing treatment period from 20 minutes to 60 minutes. Similar trend was observed in the case of cold water treatment when treatment period was increased from 1 day to 3 days. The maximum retention (20.37 kg/m3) was observed from the samples treated with 10% BB solution for 60 minutes and in 2.5% BB treated samples, the average retention gradually increased from 5.35 kg/m3 to 7.16 kg/m3 when treatment duration was varied from 20 to 60 minutes. In the case of cold water treatment, maximum retention (22.97kg/m3) was observed from the veneers treated with 10% BB solution for 3 days and 7.35 kg/m3 retention was obtained when treated with 2.5% Borax-boric acid solution for 1 day. According to the Indian Standard (IS-1902), the retention of 4 kg/m3 boron compounds are sufficient to offer protection for non-structural purposes.
K Akhter, Md Abul Hashem, S Akhter
Effect of preservative treatment on dimensional stability of plywood made of treated simul (Bombax ceiba) veneer
2012 - IRG/WP 12-40575
The dimensional stability such as thickness swelling and water absorption of plywood made of treated simul (Bombax ceiba) veneers were investigated after 2 hours and 24 hours soaking under water. The veneers were treated with hot water and cold water solution of borax-boric acid (1:1), neem leaves and mahogany seeds of different concentration (1:10, 1:20, and 1:40) at different treatment duration. It was observed that the values of swelling were increased with the increase of soaking time from 2 hours to 24 hours. In the case of plywood made of borax-boric acid treated veneers, the percentage of swelling were increased with the increase of borax-boric acid concentration. The values of thickness swelling were also increased with the increase of treatment duration from 20 minutes to 60 minutes and 1 to 3 days. The values of swelling obtained in plywood made of neem leaves and mahogany seeds treated veneers were higher than that of borax-boric acid treated veneers and near to the untreated samples. The mean values of percentage of water absorption in plywood after 2hrs and 24 hours water soaking were determined. It was found that after 24 hours soaking, plywood made of mahogany seeds treated veneers absorbed more water than that of neem leaves treated veneers. All the values obtained from treated samples after 2 hours and 24 hours soaking were lower than the control samples. But it was observed that higher amount of water was absorbed in neem leaves and mahogany seeds treated board in comparison with borax-boric acid treated board. It was also noted that the values of water absorption in leaves and seeds treated board were near the values of untreated samples.
K Akhter, M Mahabubur Rahaman, A Ara
Glue-bond strength of simul (Bombax ceiba) plywood made of Neem (Azadiracta indica) leaves treated veneers
2013 - IRG/WP 13-40647
The glue-bond qualities of plywood made of treated simul (Bombax ceiba) veneers were investigated. The veneers were treated with cold and hot water solution of neem (Azadiracta indica, A. Juss.) leaves of different concentrations and treatment durations. The plywoods were made at three different pressures in hot press using urea formaldehyde glue. The glue-bond strength of untreated simul plywood in dry shear-test were found to be 2.17 and 2.29 N/mm2 made at 1.05 and 1.40 N/mm2 pressure respectively. It was observed that the glue-bond strength of neem leaves cold water treated (1:10) simul plywood in dry shear-test were 2.01 to 2.29 N/mm2 made at 1.05, 1.40 and 1.76 N/mm2 pressure. It was found that the values of load at failure of treated simul plywood in dry shear-test were gradually decreased with the increasing treatment duration and concentration of solution. For maximum treatments, lower values of shear strength were observed in plywood made of hot water-treated veneer compared to that of cold water-treated veneer. However, the values of glue bond strength in all Neem Leaves (NL) treated plywood met ‘A-grading’ requirement for gluing.
K Akhter, M A Hashem, S Akhter