Your search resulted in 93 documents. Displaying 25 entries per page.
Implications for comparability of laboratory experiments revealed in studies on the effects of population density on the vigour in groups of Coptotermes lacteus (Froggatt) and Nasutitermes exitiosus(Hill) (Isoptera: Rhinotermitidae, Termitidae)
1983 - IRG/WP 1197
(Summary of paper 1194)
The vigour - survival and wood consumption - of groups of Coptotermes lacteus and Nasutitermes exitiosus was measured when termites were kept at different population densities (g termites/ mL) by changing group size and/or volume of the holding container. A characteristic pattern emerged. At low population densities (< 0,01 g/mL) performance of termites improved with an increase in group size; at higher population densities it tended to decline. The impact of altering group size and container volume on termite vigour was most pronounced at low densities; at higher population densities, performance tended to be more stable but declined markedly when termites became overcrowded. In most jar-type experiments on termites, especially those conducted in Europe and the U.S.A., small groups of termites are housed in disproportionately large jars, resulting in very low, sub-optimal population densities. Suggestions are made for improvements in experimental design that would lead to an enhancement of the comparability of results from different laboratories.
M Lenz, R A Barrett, E R Williams
Social and economocal impact of an extension of service life resulting of an adequate preventive treatment. Application to wooden components used in urban areas with a high density of population
1993 - IRG/WP 93-50001-15
Le document évalue les problèmes rencontrés en zone urbaine pour le sauvetage des constructions: coordination de la lutte, délimination des chantieres et des périmètres d'investigation, nuisances causées par les interventions, risques pour la santé, risques pour l'environnement. Coûts. Comparaison socio-économique du traitement préventif et des interventions à posteri...
A T De Lelis, G A C Lopez
Protection of a low-density mangrove timber species gewa (Excoecaria agallocha) through preparation of particleboard – An Assessment
2006 - IRG/WP 06-40348
It is now well established that the conversion of low-density and low-cost timbers into laminated, composite and densified form is an alternative of wood protection by means of wood preservatives. Once only the timber species gewa (Excoecaria agallocha) was used for manufacturing newsprint paper in Bangladesh, which is not continued today. The feasibility of commercial production of particleboard ...
A A Mahfuz, M O Hannan, M A Islam, M N Islam , M M Islam, A K Lahiry
Comparative studies on penetration and retention of CCA (C) and creosote in wood from APHID-killed and sound Kenyan-grown Mexican cypress (Cupressus lusitanica)
2006 - IRG/WP 06-40352
Properties of wood from Kenyan-grown Mexican cypress (Cupressus lusitanica), attacked and killed by the cypress aphid (Cinara cupressi), in terms of density and treatability, were investigated in comparison to the properties of wood from sound trees. Density in small wood samples from aphid-killed trees was found lower than density in samples from sound trees, and reduced with tree age in samples...
R Venkatasamy, F M Opar
The influence of wood density on the durabilities of three Ghanaian hardwoods (Nauclea diderrichii (de Wild.) Merr., Nesogordonia papaverifera (A. Chev.) R. Capuron and Corynanthe pachyceras Welw.) )
2007 - IRG/WP 07-10603
Review of factors that influence wood durability shows that although density varies depending on stem position, its role on decay resistance appears controversial. The role density plays in influencing the durability of three hardwoods from Ghana, namely Nauclea diderrichii (de Wild.) Merr., Nesogordonia papaverifera (A. Chev.) R. Capuron) and Corynanthe pachyceras Welw. is therefore investigated ...
C Antwi-Boasiako, A J Pitman, J R Barnett
Theory of Aesthetics – Charm in Furniture and an Aesthetic Evaluation of Bleaching of the Natural Color of Wood through the Application of Experimental Bleaching Process
2007 - IRG/WP 07-30424
This paper consists of mainly three sections: In the first section, brief information is given on the theory of aesthetics as a branch of philosophy, historical progress of the aesthetics theory is summarized within the context of the term “beautiful”, and aesthetic values as well as the color and aesthetic effects of color in preparing the designs are explained. In the second section, relatio...
I Usta
White Rot in Eucalyptus Wood: Anatomical Changes and Density Variation by X-Ray Densitometry
2007 - IRG/WP 07-10631
Wood samples of the hybrid Eucalyptus grandis x urophylla attacked by white rot fungi were characterized. Microscopically, the colonization of the fungi was observed in the vessels and radial parenchyma, however the cell walls of the some fibers were attacked, indicating susceptibility to this fungi. Zone lines were observed as a result of interaction and compartmentalization of the fungi. Microsc...
M Tomazello Fo, S Brazolin, M P Chagas
Effect of fiber type and content on the natural durability of wood flour/high density polyethylene composites against rainbow fungus (Coriolus versicolor)
2007 - IRG/WP 07-40387
In order to evaluate the effect of fiber type and content on the natural durability of wood flour/high density polyethylene (HDPE) composites against Coriolus versicolor, samples containing 25% and 50% by weight of various natural fibers and HDPE were selected. Natural fibers included in the study were wood flour, rice hulls, hemp fibers and newsprint. Samples containing 25% and 50% natural fiber ...
A Karimi, M Tajvidi, S Pourabbasi
Effect of Compatibilizer on the Natural Durability of Wood Flour/High Density Polyethylene Composites Against Rainbow Fungus (Coriolus versicolor)
2007 - IRG/WP 07-40388
To evaluate the effect of compatibilizer on the natural durability of wood flour/high density polyethylene composites against Coriolus versicolor, composites containing 25% and 50% by weight maple wood flour and 1% and 2% compatibilizer (Maleic anhydride polyethylene (MAPE)), respectively, were sampled. Identical specimens of the same composites without the compatibilizer were also prepared. ...
Sara Pourabbasi, A Karimi, D Parsapajouh, M Tajvidi, M Soleymani
Influence of ring width and wood density on durability of oak heartwood
2008 - IRG/WP 08-10639
Oak (Quercus sp.) is considered as one of the most durable European wood species. The most important factor influencing oak durability was extractive content. In our work, we were interested in if oak-wood durability is affected by ring-width and related density. Therefore, oak heartwood specimens made of boards with different ring widths were exposed to five different fungal species Daedelea quer...
M Humar, P Oven, F Pohleven
Natural durability of fast growth plantation Eucalyptus grandis Hill, ex Maiden
2008 - IRG/WP 08-10660
One of the fast growing species cultivated in Uruguay of mayor economical importance is Eucalyptus grandis. Physical and mechanical properties of juvenile and mature wood from different regions have been deeply studied. However, since no scientific data of natural durability of this specie has been reported, natural durability of E. grandis from two sites (Rivera and Rio Negro) was evaluated. Two ...
S Böthig, A Sánchez, J Doldán
Surface color and roughness characteristics of medium density fiberboard (MDF) panels treated with fire retardants
2008 - IRG/WP 08-40420
The objective of this study was to determine surface characteristics and color change properties of Medium Density Fiberboard (MDF) treated by fire retardants (FR) with 10% concentration. Experimental panels were made using by melamine ureaformaldehyde (MUF) adhesive having 10%, 15%, 20% of melamine. The surface properties of the samples were determined using a fine stylus technique. Three roughn...
D Ustaömer, M Usta, S Hiziroglu
Categorization of 300 timber, bamboo and cane grown in Bangladesh based on their families, origins, growths, physical and mechanical properties
2009 - IRG/WP 09-10684
In this study the 300 timber, bamboo and cane plants grown in Bangladesh have been classified into various categories based on their taxonomic families, origin of species, rate of growth, color of wood, texture of wood, shrinkage of wood, equilibrium moisture content (EMC) of wood, flammability of wood, cutting and sawing properties of timber, finishing and polishing qualities of wood, machining p...
A K Lahiry
Dimensional Stability of Nine Tropical Hardwoods from Cameroon
2009 - IRG/WP 09-10687
This study investigated the swelling behavior, rate of swelling and dimensional stability of nine tropical hardwood species from Cameroon, namely ayous (T. scleroxylon), bilinga (N. diderrichii), bubinga (G. tessmannii), iroko (C. excelsa), Makore (M. heckelii), moabi (B. toxisperma), movingui (D. benthamianus), teak (T. grandis) and zingana (M. brazzavillensis). Continuous swelling was monitored ...
S R Shukla, D P Kamdem
Barefoot-heat-impact of oil-heat-treated wood: An important thermal property of decking boards
2009 - IRG/WP 09-40458
In this study the phenomenon of sensual heat impression was examined, when walking with bare feet on sun exposed wood based decking boards. A suitable method for measuring the heat flux from decking boards into an artificial foot was developed. The method and measuring device is described as well as results from measuring three different decking board materials: Oil-heat-treated spruce (OHT), untr...
A O Rapp, C R Welzbacher, C Brischke
Glutathione transferases as functional biomarkers of wood degradation?
2010 - IRG/WP 10-10735
The recent release of several fungal genome sequences allows the report of an overview of fungal glutathione transferases (GSTs) focused on their function in the wood-degrading basidiomycete Phanerochaete chrysosporium. A genomic and phylogenetic analysis of GST classes in various sequenced fungi –zygomycetes, ascomycetes and basidiomycetes- revealed some specificity in GSTs distribution, in com...
E Gelhaye, M Morel
The Effects of Some Fire Retardant Chemicals on the Decay Resistance of Medium Density Fiberboard (MDF)
2010 - IRG/WP 10-30536
The objective of this study was to determine the decay resistance of Medium Density Fiberboard (MDF) treated with 5% and 10% concentration of various fire retardant (FR) chemicals. Experimental panels were produced using by melamine-urea-formaldehyde (MUF) resins having 10%, 15% and 20% of melamine content. MDF specimens were subjected to decay resistance test performed according to modified EN 11...
D Ustaömer, M Usta, Ü C Yildiz, S Yildiz, E D Tomak
Lignin blocking effects on weathering process of wood plastic composites
2010 - IRG/WP 10-40529
The weathering of wood–plastic composites (WPC) causes discoloration which affects their aesthetic aspects. It has been proved that these discolorations are due to lignin degradation. Effects of blocking the susceptible structure of lignin assessed by chemical treatment such as acetylation and methylation are reported in this study. Surface chemical change of wood plastic composite (WPC) formula...
P Darabi, A Naghi karimi, S Ahmade Mirshokraie, M-F Thévenon
Comparative Study of Heat Treatment of Beech Wood in Hot Water and Steam Medium
2010 - IRG/WP 10-40536
Heat treatment of wood is an effective method to improve the dimensional stability and durability against biodegradation. Heat treatments of beech wood in 2 different mediums (hot water and steam) in 180ºC were compared in physical, mechanical and anatomical properties. Mass loss in hydrothermally treated wood was higher than hygrothermally treated samples. Mechanical properties (MOR, MOE and CS)...
A Talaei, K Yaghoobi, A N Karimi
Thermally modified timber (TMT) for decking applications – determination of relevant surface properties
2011 - IRG/WP 11-40544
In recent years thermally modified timber (TMT) entered various market segments. It is used for facades, horticultural equipment, garden furniture, and also for kitchen and bathroom cabinets. However, flooring turned out to be the most important application for TMT, either as interior parquet or as exterior decking. Besides durability and dimensional stability, which had been the initial target pr...
L Meyer, C Brischke, C R Welzbacher
Effects of Nano-Wollastonite on Ignition Time Reduction in MDF
2012 - IRG/WP 12-40576
Effects of wollastonite nano-fibers on ignition time reduction in medium density fiberboard were studied. Nanowollastonite was applied at 5, 10, 15, and 20 g/kg dry weight basis of wood fibers and compared with control specimens. Two application methods of nanowollastonite were used: surface application, and internal application. Specimens of 150×130×9 mm were prepared and the ignition times wer...
H Reza Taghiyari, H Rangavar, P Noori, A Karimi
Effects Of Wood Preservative On Mechanical Properties Of Glulam Manufactured From Lower Density Malaysian Tropical Timber
2012 - IRG/WP 12-40590
This study is to investigate the effect of wood preservative on the mechanical properties of glulam timbers made from low density Malaysian hardwood timbers. Utilization of lower density Malaysian tropical timber for structural applications have not exploited extensively due to their inferior strength. By converting into treated glued laminated (glulam) timbers it could offer the possibility of th...
L Francis, Z Ahmad
Liquefaction - a functional way to manage CCB containing post-consumed wood?
2012 - IRG/WP 12-50288
The need for increased use of renewable resources put quite some attention to liquefaction of biomass, including wood. Several possible applications of liquefied wood as an alternative to petroleum based derivatives have been considered in recent years. In this paper, possibilities of wood liquefaction to manage post-consumed CCB (copper, chromium, boron) containing wood are considered, with a foc...
M Petrič, F Budija, D Hrastnik, M Humar, B Lesar
Statistical analysis of durability tests - Part 1: Principles of distribution fitting and application on laboratory tests
2013 - IRG/WP 13-20504
Service life prediction is an important topic in wood research, especially with regard to the Construction Products Regulation (CPR). Both laboratory tests as well as in-service performance testing are therefore essential in combination with proper monitoring and analysis tools. A crucial concept is variability in testing and analysis, especially for a biological material such as wood. The larger ...
I De Windt, J Van den Bulcke, C Brischke, C R Welzbacher, A Gellerich, S Bollmus, M Humar,
Statistical analysis of durability tests - Part 2: Principles of time-to-failure and application on field test data
2013 - IRG/WP 13-20512
Service life prediction is an important topic in wood research, especially with regard to the Construction Products Regulation (CPR). Both laboratory tests as well as in-service performance testing is therefore essential, in combination with proper monitoring and analysis tools. A crucial concept is variability and the incorporation of variability in tests and analysis. In this paper we focus on t...
J Van den Bulcke, I De Windt, C Brischke, C R Welzbacher, A O Rapp, J Van Acker