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Biofouling and bioresistance of bamboo in marine environment
2003 - IRG/WP 03-10482
Proudly known as “green gold” and popularly called as “poor man’s timber”, bamboo is closely interwoven with the life of scores of people around the globe because of its versatile qualities and desirable strength properties as a structural material. It is used for innumerable purposes both on land and in water including seas and brackishwater bodies. "Presently, bamboos constitute an important raw material, and are vital to the economy of many countries" (John et al, 1995). In the words of Hanke (1990), "it is difficult to exaggerate the importance of bamboo as a structural raw material for most of human kind". "The 500-plus species are scattered throughout the warmer parts of the world, but the family achieves greatest abundance and most impressive luxuriance around the southern and southeastern edge of Asia, from the Indian monsoon region through China and Japan to Korea". Annually, about 4.56 million tons of bamboo from 30 genera comprising of 136 species is exploited in India alone (Anonymous, 1989). A vast quantity of it is used in the marine sector as fishing rods, sail masts, stakenet poles, mariculture cages and poles, fishing screens, fishing net supports, fish traps, fish baskets, floats for nets, floating rafts, floating fenders, floating platforms, etc., right from conventional capture fisheries to the most modern mariculture operations (Purushotham, 1963, Suri and Chauhan, 1984 and Santhakumaran and Sawant, 1993). Use of 30 lakh culms of bamboo per year for strikingly large screens of up to 10 Km and several other devices was reported by Satyanarayana Rao et al (1992) from Kolleru Lake in Andhra Pradesh, India, where brackishwater conditions prevail during certain seasons/in certain pockets. Similarly, bamboo cages of varying dimensions from 4 x 4 x 5 m to 50 x 5 x 5 m are reported to be employed for open ocean culture of fishes in Kampuchea, Indonesia and Thailand (Nayak, 2001). In all these utilities, bamboo is mostly used in untreated form. Yet, precise data on biofouling and bioresistance of different species of bamboo under marine conditions are not available except for isolated reports like that of Santhakumaran and Sawant (1993). Therefore, studies in this direction were taken up. Initially three widely used commercial Indian species of bamboo were tested and their performance is presented in this paper.
M V Rao, M Balaji, V Kuppusamy, K S Rao


Assessing the bioresistance conferred to solid wood by chemical modification
1997 - IRG/WP 97-40099
The chemical modification of wood using straight chain alkyl anhydrides can considerably enhance its durability. This paper presents an assessment of the effectiveness of these modifiers in improving the biological resistance of a susceptible softwood when exposed to four different basidiomycete fungi, soft rots and the larvae of the house longhorn beetle (Hylotrupes bajulus). It was clear that some of the standard tests were inappropriate for the testing of chemically modified timber products because the procedures relied upon the wood achieving relatively high moisture contents. Nevertheless, the data overall did indicate that resistance to biological attack could be enhanced through chemical modification. Suggestions are made for the development of test methods that can be applied to chemically modified wood and wood polymer composites of low hygroscopicity.
E D Suttie, C A S Hill, D Jones, R J Orsler


Bioresistance of Poplar Wood Compressed by Combined-Hydro-Thermo-Mechanical Wood Modification (CHTM) Process
2010 - IRG/WP 10-40532
Bioresistance of treated Poplar wood by CHTM process (Combined-Hydro-Thermo-Mechanical Wood Modification) was studied in the current research work. Resistance against brown rot fungus Gloeophyllum trabeum as well as the soft rot decay was the main concern of this work. Poplar wood blocks were hydrothermally treated at temperatures of 120,150 and 180°C for holding time of 0, 30 and 90 min. afterwards, the blocks were compressed at temperatures of 160 and 180°C for 20 min. The treated blocks were oven dried for 24 hours at 103±2°C. Small specimens were cut from the blocks and exposed to the brown rot fungus according to EN 113. Also, mini-stakes were prepared and exposed to soil according to ENV 807. Results revealed that the bioresistance of the CHTM treated poplar wood increased due to the hydrothermal modification. Increase of the holding time as well as the press temperature reduced the fungal activity in the CHTM treated wood. According to the results of previous and the current works, the treated wood at temperature of 150°C for a holding time of 30min and compressed at press temperature of 180°C was selected as the best treatment.
L Khademi-Bami, B Mohebby


Biological resistance of acetylated particleboards exposed to white (Trametes versicolor (and brown (Coniophora puteana) rot fungi
2010 - IRG/WP 10-40534
This research was conducted to investigate the effect of acetylation on bioresistance of particleboard produced from acetylated wood chips of Fagus orientalis exposed to white (Trametes versicolor (and brown (Coniophora puteana) rot fungi. After 12 hours soaking in acetic anhydride, in order to achieve three level of weight gains, 5, 9 and 16%, acetylated particles were heated in an oven at 120 c˚ for 30, 90 and 240 minutes, respectively. Acetylated and nonacetylated (control) boards were produced with 10% melamine urea formaldehyde (based on the oven-dry weight of particles) and pressed. These boards were tested for decay according to EN113 standard method. Results showed that by increasing level of acetylation, bioresistance of boards increases for both white and brown rot. But, this effect is more obvious for white rot. In fact, by increasing the level of acetylation from zero to 16%, the weight loss of white rotted samples was altered from 21.8% to 0.97% and from 36.3% to 1.78% and for brown rotted samples was altered from 32.6% to 11.3% and from 42.9% to 12.8% after 12 and 16 weeks, respectively.
M Ghorbani kokandeh, K Doosthoseini, A N Karimi, B Mohebby, H Asghari