Your search resulted in 14 documents.
Environmental impact of PCP and NaPCP in the aquatic and atmospheric compartment
1995 - IRG/WP 95-50040-06
PCP and NaPCP were studied for their aquatic toxicity on bacteria, microalgae and daphnids and for their behaviour in the atmospheric compartment with a climatic chamber. Results of aquatic toxicity bioassays showed that toxicity was higher at low pH. This can be explained by the pKa value of 4.7 of PCP and the higher concentration of the non dissociated form of the pesticide at more acidic pH. Volatilization of pentachlorophenol was studied with wood samples treated with PCP in organic solvent or aqueous solution of NaPCP. Test procedures were investigated in a first step. It appears that a period of three weeks minimum after impregnation must be respected before sampling the wood specimens and that the ratio m²/m³ has to be in good agreement with the saturated vapor pressure concentration. These recommandations would imply improvement of some conditions of the French norm NF X 41-566. The release of pentachlorophenol from wood samples treated with PCP was much higher than with wood treated with NaPCP. The different behaviours of PCP and NaPCP suggest that these substances should be considered distinctly.
P Marchal, P Vasseur, G Ozanne
A technique for the quantitative isolation of Actinomycetes from decayed wood
1980 - IRG/WP 1116
A technique combining comminution and high-speed homogenisation has been developed for the preparation of suspensions of micro-organisms in colonised wood. When standard inocula of Streptomyces spores were applied to wood, constant proportions of the inocula were recovered. This method was used in conjunction with selective culture media to isolate actinomycetes from wood which had been buried in soil for varying time-periods. It was found that numbers isolated rose from 6x102/g colonised wood after 1 week's burial in soil to 9x108/g colonised wood after 21 weeks experience suggesting that a considerable proportion of the microbial population at the end of succession in decaying wood are actinomycetes.
A A W Baecker, B King
The degradation of wood surfaces by water
1984 - IRG/WP 3289
Thin radial/longitudinal sections (~100 µ) of Scots Pine (Pinus sylvestris) and lime (Tilia vulgaris), were exposed to deionised water over the temperature range 25-65°C. Losses in wet tensile strength and toughness occurred rapidly at temperatures from about 50°C upwards. After about 2 months' exposure pine lost some 10-30% of its tensile strength and 20-60% of its toughness. For lime the losses were somewhat greater, being about 20-60% for tensile strength and up to about 80% for toughness. Further prolonged exposure for about 18 months led to about 60% tensile strength loss in pine and 80% in lime. For both species some 90% loss in toughness occurred after this period of exposure. Dry tested specimens and those tested wet but at "zero span" retained a much higher proportion of their original strength. These specimens failed mainly by simple intra-fibre fracture, whereas the lime specimens tested wet at finite span, showed marked inter-fibre shear failure. No such clear cut distinction in failure mode could be observed with pine, although in this species also, scanning electron micrography showed marked degradation in the middle lamella region. It is believed that the phenomena reported are due purely to physicochemical processes and that they may contribute significantly to detachment of paints and other finishes from wood surfaces.
W B Banks, P D Evans
Soluble nutrient influences on toxicity and permanence of CCA preservatives in wood
1980 - IRG/WP 3144
The influence of soluble carbohydrate and nitrogenous components concentrated at evaporative surfaces of wood on the toxicity and permanence of CCA preservatives has been examined using soil-burial techniques. Nutrient concentrations in lime (Tilia vulgaris Hayne) have been shown to be associated with reduction of toxic limits of preservatives to an extent in which a 100% increase in preservative loading is required to provide adequate protection in the presence of soluble nutrient gradients. Toxic limit reduction was seen to be accompanied by nitrogen increases. The latter were attributed to microbial biomass which suggests a significant involvement of sacrificial colonisation by micro organisms. Preliminary analyses of elemental copper and chrome indicate an associated preservative instability.
B King, G M Smith, A Bruce
Étude de l'impact d'un xénobiotique sur le milieu aquatique: Approche méthodologique
1990 - IRG/WP 3586
L'action de xénobiotiques sur les communautés vivantes des écosystèmes lénitiques a été abordée à des échelles spatiotemporelles différentes. Dépassant le niveau des tests monospécifiques, nous avons effectué des essais en laboratoire sur des microcosmes contenant des végétaux ( Lemna minor ) et des bactéries et également sur des bassins de quelque m³ contenant une grande variété d'organismes. Les essais ont porté jusqu'à présent sur le Pentachlorophénol; ils seront poursuivis prochainement sur d'autres composés. Les résultats obtenus au laboratoire se sont avérés être transposables aux effets obtenus dans les bassins: le développement de souches bactériennes résistantes au PCP et l'inhibition de l'activité photosynthétique des différents groupes de végétaux constituent les principaux résultats de la contamination par le fongicide. Ces effets reposent sur les caractéristiques de dispersion et d'accumulation du produit étudiées par ailleurs. Il s'avère que l'approche méthodologique multidimensionnelle utilisé içi est très efficace et elle sera utilisée pour vérifier les effets d'autres xénobiotiques sur la structure et le fonctionnement des écosystème aquatiques.
G Blake, G Merlin
Main problems of Turkish wooden boat manufacturers
1982 - IRG/WP 485
The best transportation system to the eastern Black Sea region of Turkey has been since the earliest history sea transportation. As is well known the historical 'silk road' from Europe to the Far East and China was over the Black Sea and via Trabzon. During the last five years also this same connecting route has become very important for the transportation of food and industrial products from the West to the Middle East. Two other factors that are influencing the building of boats in this region are the local rich forest resources and fishing facilities. It can be pointed out that 80% of the Turkish sea food is produced in the Black Sea region, which amounts to 380,000 tons per year. Therefore the main purpose of boat building in this area can be attributed to the needs of the fishing industry
The effect of aqueous leaching on moisture uptake by CCA-treated blocks during soil burial
1987 - IRG/WP 2283
Mass loss, moisture content and nitrogen data from two soil burial experiments with untreated and CCA-treated Scots pine (Pinus sylvestris L.), Sitka spruce (Picea sitchensis Carr) and lime (Tilia vulgaris Hayne) are presented. These show that aqueous leaching of CCA-treated wood prior to burial significantly reduces its subsequent moisture uptake from soil. In the case of lime, a reduction in the rate of microbial invasion and decay of leached, treated blocks, when compared with their unleached counterparts, was demonstrated. The implications of these observations with regard to accelerated testing methods are discussed.
C A Green, G M Smith, B King
The degradation of wood surfaces by dilute acids
1985 - IRG/WP 3326
Thin radial/longitudinal sections(~100 µ) of Corsican Pine (Pinus nigra) and Lime (Tilia vulgaris), were exposed to Sulphuric, Sulphurous, nitric, acetic, and formic acid at 40°C in the pH range 2-6. After about 3 months exposure to Sulphuric, nitric, acetic and formic acid at pH 2.0 Pine lost some 20-25% of its tensile strength. Losses in tensile strength due to sulphurous acid were greater being about 60-70%. Further prolonged exposure to sulphurous acid for 12 months led to some 90% tensile strength loss in Pine and 95% in Lime. Tensile strength losses also occurred at pH 2.5 and 3.0. For Pine strength losses of some 40% and 20% occurred at pH 2.5 and 3.0 after 12 months exposure. For Lime the losses were somewhat greater being about 70% at pH 2.5 and 50% at pH 3.0. For both species even greater losses in toughness occurred after this period of exposure in the pH range 2-3. Signficant but more erratic losses in toughness also occurred at pH 3.5. The strength losses noted above are over and above those resulting due to exposure of the controls to deionized water alone. During a similar time period exposure to deionized water led to losses in tensile strength for both species of some 15-20%. Losses in toughness were even greater being in the range 20-40%. Lime specimens tested wet showed a tendency to fail by inter-fibre shear in the middle lamella region. Scanning electron micrography also showed degradation of the middle lamella in Pine. It is believed that the degradational phenomena reported here are due to physico-chemical processes and that they may contribute to the degradation of paints and other finishes from wood surfaces.
P D Evans, W B Banks
Chapter 12 - Treatment Groups of Bamboo
2007 - IRG/WP 07-10635-12
Study on distribution of CCA in three major bamboo species in Bangladesh, full-cell pressure treated at green and dry conditions revealed two treatment groups and some treating principles. Higher adequate treatment for ground and water contact use is only possible by treating problematic bamboo species pre-kiln dried up to half of its FSP and non-problematic species pre-dried up to FSP (20% MC). The non-problematic species can be treated in green conditions for indoor and overhead outdoor uses. Two smallest holes made before treatment in each internode will give split-free bamboo.
A K Lahiry
Chapter 13 - Slow fixation of CCA-treated bamboo
2007 - IRG/WP 07-10635-13
Chromated copper arsenate (CCA) leachability tests on full-cell pressure impregnated (with 2-3% CCA solution) and slow dried (six months air-drying under cover) bamboo block of three major bamboo species of Bangladesh revealed initial insignificant leaching of CCA within first week and no leaching in next week. Use of low concentration of CCA, release of particle form of CCA due to exposure of bamboo blocks by cutting and presence of watersoluble extractives in bamboo might be the causes for initial leaching of CCA.
A K Lahiry
Treating Bambusa vulgaris with neem seed oil against basidiomycetic biodegradation
2012 - IRG/WP 12-30608
Realising maximum benefits from bamboo stems/culms in Nigeria are presently constrained by their almost non-acceptance for applications in most structural and construction purposes, except in comparatively low quality and some temporary applications, such as scaffolding, owing to their susceptibility to easy destruction by agents of biodegradation as a result of their poor inherent natural durability. Therefore, there is the need for value-addition to this lignocellulosic material using low cost preservatives, particularly the environmentally benign ones, in order to encourage sustainable utilisation for higher valued products and contribute to poverty alleviation in this part of the world. This report is an outcome of an investigation on the efficacy of neem (Azadirachta indica A. Juss) seed oil-treatment for bamboo (Bambusa vulgaris Schrad. ex J.C. Wendl.) against a fungus, also a basidiomycete, known as Pycnoporus sanguineus (L. ex Fr.) Murr. Oven-dried split-bamboo samples conditioned to 11.76% mean moisture content were converted to test specimens for percentage weight loss (PWL) and treated with mechanically extracted neem seed oil (NSO) at two different treatment temperature regimes by completely soaking a set in NSO at ambient room temperature of 25 ± 2oC for 24 hours and soaking the other in NSO at 60oC for 4 hours with untreated samples serving as control. The oil-treated and control samples were initially weighed and subsequently inoculated with cultured P. sanguineus and monitored in an incubating room maintained at ambient temperature of 25 ± 2oC and 65 ± 5% relative humidity for 12 weeks (84 days). After the 84 days incubation period, the test specimens were then reweighed and the PWL determined. Results showed that mean values for PWL was highest for those obtained for control samples (18.21%), comparatively lower for samples soaked in NSO at 25 ± 2oC for 24 hours (5.88%) and lowest for samples soaked in NSO at 60oC for 4 hours (2.21%). Implications of these values were discussed while conclusions and recommendations were based on the outcome of the study.
A A Erakhrumen
Development of composite furniture using bamboo strips, bamboo mat and rubber wood veneer
2014 - IRG/WP 14-40679
Bamboo offers cost-effective component in panel form is well suited to wood substitute can be used as furniture components. In the present study, borak (Bambusa balcooa ) bamboo were used for manufacturing bamboo panel. Mitinga (B. tulda) bamboo were used for making mat and rubber wood veneers were used for manufacturing mat overlaid veneer board. Borax-boric acid (BB) treatments were given to enhance the durability of mat, strips and veneer. The treatments were carried out using borax-boric acid (1:1) aqueous solution of different concentrations at different time schedule by soaking process. The optimum retention of preservative chemicals through mat, strips and veneer were determined. Using 5% BB solution, the average retention was found 21.90 kg/m3 in A (1.22 m X 0.91m) size mat and 24.39 kg/m3 in the B (0.61 m X 0.91m) size mat after 3 days soaking. Using 7% solution, retention of 25.17 kg/m3 A size mat and 28.44 kg/m3 were obtained in B size mat after 3 days treatment. In the case of bamboo strips, highest retention of 26.22 Kg/m3 was found when treated with 7% solution for 3 days. Highest retention 24.53 kg/m3 was obtained in 7% BB treated rubber wood veneers after 3 days soaking. Average retention of 22.07 kg/m3 was found when veneers were treated with 5% BB solution for 3 days. It was observed that, veneers were treated with 7% BB solution attained average retention of 19.20 to 24.53 kg/m3 after 1 to 3 days treatment. It was found that the retention were gradually increased with increasing concentration and time period. After preservative treatment, the materials were used in making composite products for chair.
K Akhter, M Mahabubur Rahaman, M H Chowdhury, M Zahirul Alam
Natural resistance of Bambusa vulgaris to termite and powder-post beetle attack in laboratory and graveyard tests
2018 - IRG/WP 18-10925
Deterioration is the major setback to the utilisation of bamboo products. To enhance bamboo utilization, an understanding of the level of resistance to degradation is important. In this study, level at which Bambusa vulgaris will naturally resistant attack by subterranean termites and powder-post beetles were evaluated. B. vulgaris aged 2, 3 and 4 years were subjected to attack by subterranean termites and powder-post beetles for six month in a short span field tests. After the exposure period, the weight loss due to attack were determined in order to evaluate the level of natural resistance to the selected degrading insects. There was significant variation in the termite resistance among the three age classes while no variation occurred along the culm length. In contrast to termite resistivity, resistance to powder-post beetles infestation varied significantly along the culm length from base to the top while the resistance among the three age classes were similar. The bamboo was grouped into resistant classes based on the age and the portion of the culm from which samples were extracted. Bamboo aged 4 exhibited highest resistance to termites and were therefore placed in “Resistant” class while bamboo from age 3, basal and middle portion were placed in “Moderately resistant” class. The resistance of B. vulgaris from all the age classes and culm portion against powder-post attack was poor and were placed in class IV. B. vulgaris resistivity to termite and powder-post attack had significant negative correlation with culm age and portion respectively. Generally, the findings of this work showed B. vulgaris natural resistant to termite depend on culm age while that of powder-post is indifferent to age or the culm portion.
N A Sadiku, S O Bada
Hydrolytic stabilization of chemically modified Bambusa vulgaris Shrad ex JC Wendl
2018 - IRG/WP 18-40830
The main drawback which greatly limit the utilisation of bamboos is their high moisture intake, biodegradation and physical properties changes with environmental variations. To prevent excessive dimensional changes and improve moisture properties of bamboo, Bambusa vulgaris was chemically treated with acetic-anhydride without co-solvent. To evaluate the influence of acetylation on the moisture properties. The weight gain (WPG), Bulking coefficient (BC), Rate of reaction (RR), Volumetric Swelling (VS) and Anti-swelling Efficiency as well as changes in VS and ASE upon long term water soaking and weight loss to leaching (WL) were determined. The results indicated no significant effect of reaction temperature and time on the WPG, BC, VS and ASE of the acetylated bamboo while reaction time had significant influence on RR and WL. None of the bamboo samples had more than 3.67% WPG and 54.69 % ASE. The maximum values of ASE of acetylated bamboo was 54.69% at 2.785 WPG while the lowest 13.08% was recorded at 2.89% WPG. However, at the lowest WPG of 1.61 %, ASE of 35.88% was recorded while the highest WPG of 3.67% gave ASE of 32.84 %. ASE varied from 13.08 % to 54.69% the lowest being recorded at 140oC, 30 mins reaction time while the highest (54.69%) was recorded at 100oC, 90 minutes reaction time. Temperature had no influence on the initial and final volumetric swelling and final anti-swelling efficiency of the modified bamboo samples but reaction time had significant effect on initial ASE. Volumetric swelling of modified samples increased from 8.47 to 18.58% while the unmodified samples swelled from 9.42% to 43.22% within 7 days water soaking period. Acetic anhydride form chemical bonds that are stable to solvent extraction in B. vulgaris. Acetylating at 120°C for 30 and 60 minutes is suitable for B. vulgaris to positively influence its sorption properties.
N A Sadiku, S M Akintayo