Search

Costa Rica produces a considerable, important quantity of wood residues. This waste can be pyrolyzed to produce charcoals as main products that can be effectively used as an energy source or to immobilize carbon for soil treatment. However, there is a lack of information about the pyrogenic carbonaceous materials (PCMs), such as charcoal or biochar, obtained at different pyrolysis temperatures. Hence, this study aimed to evaluate the quality of PCMs (physical, mechanical, ultimate analysis, and FTIR analysis) and charcoal characteristics (energetic properties and thermogravimetric analysis—TGA) and biochar characteristics (conductivity, pH, initial contact angle, and wetting rates) for four tropical wood residues produced in five temperatures (300 °C, 350 °C, 400 °C, 450 °C, and 500 °C). In general, pyrolysis temperature between 450 °C and 500 °C produced charcoals with lower values of density, moisture content, compression strength, volatiles, H and O content, and higher values of C and ash contents, conductivity, pH, initial contact angle, and wetting rates. FTIR and TGA analyses show that celluloses and lignin are pyrolyzed at these temperatures, so these temperatures are recommended. The range of 300–350 °C is not recommended, as these parameters were inverse. Multivariate analysis shows that (i) PCMs obtained at lower temperatures (300–350 °C) from Dipteryx panamensis, Hieronyma alchorneoides, and Tectona grandis belong to a cluster with poorer properties, indicating that these temperatures are not adequate for pyrolysis of these species; (ii) all the PCMs obtained from Gmelina arborea were grouped into one cluster, suggesting different PCM quality; and (iii) the PCMs produced from D. panamensis, H. alchorneoides, and T. grandis at 400–500 °C were grouped into another cluster with better properties, suggesting this pyrolysis temperature range as the best for these species. [ABSTRACT FROM AUTHOR]

Costa Rica produces a considerable, important quantity of wood residues. This waste can be pyrolyzed to produce charcoals as main products that can be effectively used as an energy source or to immobilize carbon for soil treatment. However, there is a lack of information about the pyrogenic carbonaceous materials (PCMs), such as charcoal or biochar, obtained at different pyrolysis temperatures. Hence, this study aimed to evaluate the quality of PCMs (physical, mechanical, ultimate analysis, and FTIR analysis) and charcoal characteristics (energetic properties and thermogravimetric analysis—TGA) and biochar characteristics (conductivity, pH, initial contact angle, and wetting rates) for four tropical wood residues produced in five temperatures (300 °C, 350 °C, 400 °C, 450 °C, and 500 °C). In general, pyrolysis temperature between 450 °C and 500 °C produced charcoals with lower values of density, moisture content, compression strength, volatiles, H and O content, and higher values of C and ash contents, conductivity, pH, initial contact angle, and wetting rates. FTIR and TGA analyses show that celluloses and lignin are pyrolyzed at these temperatures, so these temperatures are recommended. The range of 300–350 °C is not recommended, as these parameters were inverse. Multivariate analysis shows that (i) PCMs obtained at lower temperatures (300–350 °C) from Dipteryx panamensis, Hieronyma alchorneoides, and Tectona grandis belong to a cluster with poorer properties, indicating that these temperatures are not adequate for pyrolysis of these species; (ii) all the PCMs obtained from Gmelina arborea were grouped into one cluster, suggesting different PCM quality; and (iii) the PCMs produced from D. panamensis, H. alchorneoides, and T. grandis at 400–500 °C were grouped into another cluster with better properties, suggesting this pyrolysis temperature range as the best for these species.

Magnetic wood is a composite material that achieves harmony between both woody and magnetic functions through the active addition of magnetic characteristics to the wood itself. In addition to showing magnetic characteristics, magnetic wood offers low specific gravity, humidity control and acoustic absorption ability. It has potential for broad applications in the fields of electromagnetic wave absorption, electromagnetic interference shielding, furniture, etc. This work reports on the synthesis of Fe3O4 nanoparticles (NPs) in wood from three tropical species (Pinus oocarpa, Vochysia ferruginea and Vochysia guatemalensis) using a solution of iron (III) hexahydrate and iron (II) chloride tetrahydrate with a molar ratio of 1.6:1 at a concentration of 1.2 mol/L ferric chlorate under 700 kPa pressure for 2 h. Afterward, the wood samples were impregnated with an ammonia solution with three different immersion times. The treated wood (wood composites) was evaluated for the weight gain percentage (WPG), density, ash content and Fe3O4 content by the Fourier transform infrared spectroscopy (FTIR) spectrum, X-ray diffraction (XRD) and vibrating sample magnetometry (VSM). The results show that the species P. oocarpa had the lowest values of WPG, and its density decreased in relation to the untreated wood, with lower ash and Fe3O4 NP content. The XRD and some FTIR signals associated with changes in the wood component showed small differences from the untreated wood. Fe3O4 NPs presented nanoparticles with the smallest diameter of (approx. 7.3 to 8.5 nm), and its saturation magnetization (Ms) parameters were the lowest. On the other hand, V. guatemalensis was the species with the best Ms values, but the wood composite had the lowest density. In relation to the different immersion times, the magnetic properties were not statistically affected. Finally, the magnetization values of the studied species were lower than those of the pure Fe3O4 nanoparticles, since the species only have a certain amount of these nanoparticles (NPs), and this was reflected proportionally in the magnetization of saturation. [ABSTRACT FROM AUTHOR]

ABSTRACT Agroforestry systems (AFSs) integrate, through sustainable practices, agricultural and forest crops for the production of wood and food, providing environmental services, and conserving biodiversity. The freijó (Cordia goeldiana) has potential for cultivation in the Amazon for timber purposes, but data on the characteristics of its wood produced in AFSs are scarce. Our objective was to determine the physical-mechanical properties and suggest technological applications of freijó wood produced in a multi-stratified AFS established in the state of Rondônia, Brazil in 1996. Agricultural and forest species were established in the AFS in double rows with 5.0-m x 2.5-m spacing. Three 19-year-old freijó trees were harvested for chemical, physical (density and dimensional stability), and mechanical (compression, static bending, Janka hardness, and shear strength) characterization of the wood. The wood presented a chemical composition similar to tropical hardwoods, was moderately heavy (582.63 kg m-3), and had high dimensional stability in comparison with other consecrated woods on the market (longitudinal, radial, and tangential retraction = 0.25, 4.27, and 6.83%, respectively). The values determined for parallel (32.32 MPa) and perpendicular compression (8.02 MPa), specific strength (55.32 MPa kg-1 m-3), parallel (2373.33 N) and perpendicular Janka hardness (2326.67 N), strength to static bending (63.5 MPa), and shear (5.94 MPa) were similar to the values observed in other high-density tropical woods grown in either monoculture plantations or natural forests. The wood under study is suitable for manufacture of high-value-added products, such as fine furniture, residential floors, musical instruments and structural pieces.

ABSTRACT The recent interest in constructing high and robust wooden structures has stimulated the investigation of physical and mechanical properties as well as their correlation with other important parameters of the material of tropical species like the Vatairea sp., whose popular name is angelim-amargoso, used especially in roof structures with large spans. The Brazilian Standard for wood constructions recommends using linear models to correct or estimate the strength and/or stiffness of wood correlated with moisture content and also provides the classification of hardwoods according to their characteristic strength. However, because wood is a natural, heterogeneous, and anisotropic material, certain properties may not be affected by significant differences in moisture content. Therefore, in this study, the influence of moisture content on fifteen physical and mechanical properties of Vatairea sp. wood was investigated through its characterization. The tests were carried out on 12 specimens for each property and two groups: with the moisture content of 12% and at the fiber saturation point. The Anderson-Darling test was performed to verify the results’ normality and the analysis of variance (ANOVA) to analyze the influence of moisture content on these properties. In addition, the wood was classified according to the strength classes of the Brazilian Standard, and the strength and stiffness were estimated according to the linear models proposed by the same norm. The estimated results were compared with the experimental ones through the difference calculation and percentual error of the values. It was concluded that most properties were not affected by the moisture content, and the most significant errors obtained in the estimates were for properties that were significantly influenced by the moisture content.

Clarinets are made with a variety of materials, e.g., plastic, graphite, porcelain, or even metal. However, the most commonly used material to make clarinets is wood. Today, African granadilla or African blackwood (Dalbergia melanoxylon) is the most popular and most widely used species by leading international companies in terms of clarinet production, because of its high density, color, fine texture, and exceptional durability. This species is also used to manufacture flutes, oboes, and bagpipes, making African blackwood one of the most valuable tree species in the world. However, the focus on the usage of a single species puts considerable pressure on a rare and endangered wood species. Therefore, this work aims to identify viable alternatives to African blackwood in terms of manufacturing clarinets as well as providing a similar combination of instrument characteristics that musicians and companies believe contribute to the value of the instrument, e.g., acoustics, aesthetics, and price. [ABSTRACT FROM AUTHOR]

Magnetic wood is a composite material that achieves harmony between both woody and magnetic functions through the active addition of magnetic characteristics to the wood itself. In addition to showing magnetic characteristics, magnetic wood offers low specific gravity, humidity control and acoustic absorption ability. It has potential for broad applications in the fields of electromagnetic wave absorption, electromagnetic interference shielding, furniture, etc. This work reports on the synthesis of Fe3O4 nanoparticles (NPs) in wood from three tropical species (Pinus oocarpa, Vochysia ferruginea and Vochysia guatemalensis) using a solution of iron (III) hexahydrate and iron (II) chloride tetrahydrate with a molar ratio of 1.6:1 at a concentration of 1.2 mol/L ferric chlorate under 700 kPa pressure for 2 h. Afterward, the wood samples were impregnated with an ammonia solution with three different immersion times. The treated wood (wood composites) was evaluated for the weight gain percentage (WPG), density, ash content and Fe3O4 content by the Fourier transform infrared spectroscopy (FTIR) spectrum, X-ray diffraction (XRD) and vibrating sample magnetometry (VSM). The results show that the species P. oocarpa had the lowest values of WPG, and its density decreased in relation to the untreated wood, with lower ash and Fe3O4 NP content. The XRD and some FTIR signals associated with changes in the wood component showed small differences from the untreated wood. Fe3O4 NPs presented nanoparticles with the smallest diameter of (approx. 7.3 to 8.5 nm), and its saturation magnetization (Ms) parameters were the lowest. On the other hand, V. guatemalensis was the species with the best Ms values, but the wood composite had the lowest density. In relation to the different immersion times, the magnetic properties were not statistically affected. Finally, the magnetization values of the studied species were lower than those of the pure Fe3O4 nanoparticles, since the species only have a certain amount of these nanoparticles (NPs), and this was reflected proportionally in the magnetization of saturation.

Ghana has a long history as a major supplier of high-value hardwood timber and wood products to many countries. The research seeks to assess the effects of tropical wood leachates to aquatic organisms. Hence, five wood samples were selected; Mahogany (Khaya ivorensis), Cedrela (Cedrela odorata), Emire (Terminalia ivorensis), Wawa (Triplochiton scleroxylon) and Ceiba (Ceiba pendandra) from Oboyow forest reserve in Eastern Region- Ghana to assess their toxicity to aquatic organisms. Toxicity tests: Algal (Desmodesmus subspicatus) Duckweed (Lemna minor) and crustacean (Daphnia magna) were carried out using exposures to concentrations of 20, 30, 45, 67 and 100% v/v wood leachate in control media. The high levels of phenols measured in the various wood leachates was the main cause of toxicity. The percentage median Inhibition Concentration (%IC50) of the various wood leachate, ranged from 21.5 - 55.6% with mahogany exhibiting the highest toxicity and wawa the lowest. All the wood leachates were toxic to the aquatic organisms. The %IC50 showed both confirmed and potential toxicity among the various wood leachates and established that there was significant difference between various wood leachate toxicity.

Hyperspectral and colorimetric patterns were determined from anatomical and physical aspects for the characterization of dry Peltogyne purpurea Pittier wood from natural forest trees. A sample of 24 P. purpurea wood discs was taken and anatomical characteristics (density and diameter of vessels, percentage of solitary vessels), wood density, colour (CIELab) and hyperspectral reflectance in the range of 310 to 1 100 nm in the dry wood, both in sapwood and heartwood section, were determined. Significant anatomical differences were found between sapwood and heartwood; a higher presence of solitary vessels was found in sapwood (34.28%) but with a vessel density of 27.07 pores mm'2 and diameter of 148.53 im In the colorimetry analysis, brightness and b* (yellowing) were higher in sapwood, but with significantly lower values in a* (redness), thus generating a total color difference (higher than 14.55). As regards reflectance, three significant differentiation points were found between both sections, which were at 460, 580 and 1 020 nm; when correlating these three segments, no correlation was found with the anatomical aspects, but with the density of the wood (higher than 0.69), at the color level no relationship was found with the color parameter L* (brightness), while a* only showed inverse correlations at 580 nm and linear ones with b* at 580 nm. In this study no colorimetric relationships with anatomical aspects were found. [ABSTRACT FROM AUTHOR]

The fiber saturation point (FSP) is an important parameter of wood material, related to dimensional stability and variations of mechanical performance. This paper investigated the FSP values of 15 tropical Brazilian wood species covering all strength classes of the Brazilian standard code. An additional goal was to estimate FSP value based on the wood's apparent density. The FSP values were determined by measuring the wood specimen dimensions during moisture content reduction from the saturated state. Wood densities at 0% and 12% moisture contents and basic density were determined according to the Brazilian standard code. The average FSP for all wood species was 21.6% moisture content. Among density values, good correlations were observed, and a multivariate regression model for FSP estimation based on wood densities presented a coefficient of determination equal to 13.07%. There was no correlation between FSP and wood densities, suggesting that this parameter is almost constant regardless of the wood species. [ABSTRACT FROM AUTHOR]

The aims of this work were to determine the color change and physical–mechanical properties of polystyrene glulam from three tropical wood species. Wood laminas were cut from logs harvested from a young plantation forest of manii (Maesopsis eminii), mangium (Acacia mangium), and rubber-wood (Hevea brasiliensis). The laminas were impregnated with monomer styrene that was polymerized using potassium peroxy-disulfate as a catalyst and heat. Three-layer glulam was constructed from the polystyrene laminas, using isocyanate glue and cold press. For comparison purposes, three-layer untreated glulam and solid wood samples were prepared. The results showed that the color change of polystyrene glulam was very small compared with untreated glulam. Polystyrene glulam had the highest density, while the density of untreated glulam did not differ from that of the solid wood. The moisture content of all products was matched to the environment, and fulfilled the Japanese standard. Compared with both types of glulams, solid wood had lower values for modulus of rupture (MOR), modulus of elasticity (MOE), and hardness, but higher shear strength. Meanwhile, polystyrene glulam had lower values for MOR and MOE, equal shear strength and wood failure, and higher hardness than the untreated glulam. All glulams had very little delamination in the hot water test. Only rubber-wood glulams fulfilled JAS 234-2003 for MOR, MOE, shear strength, and delamination. To obtain adequate physical–mechanical properties of glulams, medium-density wood is recommended for glulam manufacturing.

This paper aims to characterize the wood anatomy of Croton piptocalyx. To carry out an investigation of axial variation, discussing it in a functional context, helping to increase knowledge about the species. Five randomly selected 32-year-old trees were felled at the Luiz Antonio Experimental Station, located in Luiz Antonio City, São Paulo state, Brazil. From stems, discs were cut from six different stem heights (stem base, 1 m, 2 m, 3 m, 4 m, and 5 m). For each disc, samples close to the bark were removed for wood anatomy studies and specific gravity calculation. Wood anatomy of C. piptocalyx generally agrees with that of other species of the genus as described in the literature. However, variation in both quantitative and qualitative data could be related to tree age and species differences. Axial variations found in vessel element length, vessel diameter and ray height can be respectively related to the hypothesized Typical Radial Pattern based on the occurrence of shorter and narrower cells in younger parts of the wood, involving vessel element length and diameter, and mechanical requirement in the case of higher rays at the trunk base.Nosso objetivo foi caracterizar anatomicamente a madeira de Croton piptocalyx, investigando a variação axial e discutindo-a em um contexto funcional, contribuindo para aumentar o conhecimento sobre a espécie. Cortamos aleatoriamente cinco árvores com 32 anos de idade na Estação Experimental de Luiz Antonio, na cidade de Luiz Antonio, São Paulo, Brasil. Dos troncos retiramos discos em seis alturas diferentes (base do tronco, 1 m, 2 m, 3 m, 4 m e 5 m). Em cada um dos discos, retiramos amostras próximas à casca para estudos anatômicos e determinação da densidade aparente. A anatomia da madeira de C. piptocalyx em geral é similar com o que já está descrito na literatura para outras espécies do gênero. No entanto, há variações quantitativas e qualitativas, que em parte podem estar relacionadas às diferenças na idade de árvores e, obviamente, à diferença entre espécies. As variações axiais no comprimento dos elementos de vaso, diâmetro do vaso e altura do raio, devem estar relacionadas, respectivamente, ao Típico Padrão Radial, caracterizado pela ocorrência de células menores e mais estreitas em partes mais jovens da madeira (comprimento do elemento de vaso e diâmetro do vaso) e aos requerimentos mecânicos, no caso dos raios mais altos na base do tronco.

The main objective of this research was to investigate tropical wood sorptive properties. For selected tropical wood species (courbaril, ipe, light red meranti, merbau, tatajuba, and teak), the equilibrium moisture content was determined at 20 °C and 9, 30, 55, 70, and 97% relative humidity. The experimentally determined values were analysed using the Hailwood-Horrobin sorption model to compute the fibre saturation point and mono- and multi-layer sorption. There were significant differences in the sorption behaviour of different wood species. Generally, the fibre saturation point of tropical wood species is lower than in wood species from moderate climate zones. The lowest values of fibre saturation point were found for ipe (18.7%), courbaril (20.4%), and tatajuba (20.5%). Furthermore, chloroform-ethanol extractives content was correlated with multilayer sorption and the fibre saturation point, such that a higher content of chloroform-ethanol extractives was associated with a lower equilibrium moisture content. Therefore, chemisorption was not influenced by chloroform-ethanol extractives. Ethanol extracts showed an influence on monomolecular-bound water.

ABSTRACT The lack of use of the residues generated by the mechanical processing of wood and their inadequate disposal are challenges for the timber industry. They have potential for products with higher value. The purpose of this research was to evaluate the use of residues generated by the mechanical processing of Amazonian woods Caryocar villosum, Hymenolobium excelsum, Mezilaurus lindaviana, Erisma uncinatum, Tachigali myrmecophyla and Qualea paraensis in the high-density particleboard production. The panels produced had nominal density of 850 kg.m-3, nominal thickness of 15.7 mm and 8% of phenol formaldehyde adhesive. The physical-mechanical properties of the panels produced from each species and with a mixture of all of them in equal parts were evaluated. The specimens from the panels were prepared for physical tests (apparent density, moisture content, water absorption and thickness swelling) and mechanical tests (static bending - modulus of elasticity and modulus of rupture, and internal bond) according to the standard ABNT NBR 14810-3. The mechanical properties of the particleboards manufactured with the C. villosum, H. excelsum and T. myrmecophyla residues were generally superior than those of the other species and met one or more of the minimum requirements indicated by the ANSI A208.1 standard for (H-1 classification) and for floors production (PBU classification).

Ground contact speeds up timber decay because of the large number of microorganisms in soil. This study, we assessed the natural durability of seven tropical species using the European standard EN 807 (2001). We embedded samples of Dalbergia granadillo, Cordia elaeagnoides, Swietenia humillis, Tabebuia donell-smithii, Hura polyandra, Enterolobium cyclocarpum and Tabebuia rosea and temperate species Fagus sylvatica (as a control) in sandy, clay-sandy-loam and clay-loam for 8, 16, 24 and 32 weeks. We evaluated durability of the samples by determining the mass loss and modulus of elasticity (MOE) loss. The results varied significantly (p < 0.001) depending on timber species and soil type considered. The D. granadillo and C. elaeagnoides were the most durable, with mass losses of 4.5%, 6.5% and MOE losses of 4.5%, 20.5%, respectively. F. sylvatica, T. rosea and E. cyclocarpum samples were the least durable, with mass losses of 22.3-25% and MOE losses of 35.8-59.8%, respectively. Decay was most aggressive in sandy-clay-loam soil followed by the clay-loam soil and finally the sandy soil.

ABSTRACT The objective of this study was to evaluate the volumetric lumber yield of four native species of the Amazon Region: Cedrinho (Erisma uncinatum Warm), Cumaru ( Dipteryx odorata Aublet), Garapeira (Apuleia leiocarpa Voguel), and Cambará (Qualea paraensis Ducke). Twelve logs of each species with different diameters were randomly selected from different sawmills in northern Mato Grosso state, Brazil. Additionally, the influence of diameter on the yield of each species was evaluated through regression analysis. Among the evaluated species, Cedrinho obtained the highest yield values, followed by Garapeira. Cumaru and Cambará showed the lowest yields, and did not differ statistically. Log diameter negatively influenced lumber yield, except for Cumaru wood, which did not present a clear relation between these parameters.

For selected tropical woods (Cumaru, Garapa, Ipe, Kempas, Merbau), a relationship was established between non-isothermal thermogravimetry runs and the wood weight loss under flame during cone calorimetry flammability testing. A correlation was found for the rate constants for decomposition of wood in air at 250 and 300 °C found from thermogravimetry and the total time of sample burning related to the initial mass. Non-isothermal thermogravimetry runs were assumed to be composed from 3 theoretical runs such as decomposition of wood into volatiles itself, oxidation of carbon residue, and the formation of ash. A fitting equation of three processes was proposed and the resulting theoretical lines match experimental lines.

Ground contact speeds up timber decay because of the large number of microorganisms in soil. This study, we assessed the natural durability of seven tropical species using the European standard EN-807 (2001). We embedded samples of Dalbergia granadillo, Cordia elaeagnoides, Swietenia humillis, Tabebuia donell-smithii, Hura polyandra, Enterolobium cyclocarpum and Tabebuia rosea and temperate species Fagus sylvatica (as a control) in sandy, clay-sandy-loam and clay-loam for 8, 16, 24 and 32 weeks. We evaluated durability of the samples by determining the mass loss and modulus of elasticity (MOE) loss. The results varied significantly (p < 0,001) depending on timber species and soil type considered. The D. granadillo and C. elaeagnoides were the most durable, with mass losses of 4,5%; 6,5% and MOE losses of 4,5%; 20,5%; respectively. F. sylvatica, T. rosea and E. cyclocarpum samples were the least durable, with mass losses of 22,3-25% and MOE losses of 35,8-59,8% respectively. Decay was most aggressive in sandy-clay-loam soil followed by the clay-loam soil and finally the sandy soil. [ABSTRACT FROM AUTHOR]

The aim of this research was to determine the influence of exposure time at 60 °C in the compression strength parallel to the grain (fc0) and modulus of elasticity in compression parallel to the grain (Ec0) for cupiúba (Goupia glabra), eucalypt (Eucalyptus saligna), garapeira (Apuleia leiocarpa) and jatobá tamarindo (Hymeneae sp.) wood species. The factor investigated in this research was the residence time in kiln (exposure at controlled temperature 60 °C) of specimens: 0 (wood tested at room temperature and moisture content around to 12%), 168, 456, 720, and 2160 hours, simulating the reaction of the material in confined roof structures. Compression parallel to the grain tests were conducted according to the methods of the Brazilian Standard Code ABNT NBR 7190 (1997). ANOVA results indicated that the temperature (60 °C) had a significant influence in the five exposure times. All studied wood species showed an increase in the fc0 value with increasing time of exposure at 60 °C. For Ec0, this phenomenon occurred only for the jatobá tamarindo and cupiúba wood species. [ABSTRACT FROM AUTHOR]

The work aimed to evaluated the effect of heat treatment on physical and mechanical properties of Hymenolobium petraeum Ducke wood. For this, were manufactured samples with 25.0 × 9.0 × 1.7 cm which were submitted to different heat treatments, with two temperatures (180 and 200 °C) and two exposure times (2 and 4 hours), besides the control samples (without the heat treatment). After the treatments, each sample were submitted to the assays with withdrawal of subsamples for the physical (density, mass loss, equilibrium moisture content and dimensional stability) and mechanical properties (static bending and compression parallel to grain). The heat treatment provided a weight loss of wood, with the higher temperature treatments displayed the greatest losses. However, it proved effective to decrease the equilibrium moisture content and the dimensional stability. The mechanical properties were not affected to the heat treatment. [ABSTRACT FROM AUTHOR]

Copyright of Ciência Florestal (01039954) is the property of Ciencia Florestal and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This study aimed to verify the behavior of wood Angelim stone (Hymenolobium petraeum Ducke) submitted to the machining process. The study was developed in a carpentry shop in the city of Alta Floresta-MT. 36 boards with dimensions of 150 cm x 13.5 cm x 2.5 cm, length, width and thickness were randomly selected respectively for machining tests. The tests were developed according to the machinability of equipment used by the furniture industry, planing, sanding, drill and split by nail. 8 boards of wood in the stack were selected randomly to determine the moisture, according to 7190 (ABNT, 1997). The notes used for evaluation of defects resulting in the wood during the machining processes were assigned according to ASTM D 1666 (1987). It was observed that the type of angelim stone showed excellent performance in grinding tests, no scratch on the surface piece a of the burring parts and the parts free from defects, with the burning of wood. In cracking test for nail had a good performance, because it showed cracks with the insertion of the nail and planing test a regular performance, with pullout grain, surface arrepiamento and pullout chip. Wood Angelim stone responds with quality to the machining processes in planing, sanding, drill and split by nail.

The purpose of the study was to determine the influence of artificial weathering on selected properties of wood. This paper presents the changes of incompressive strength of wood along fi bers. The study involved wood of different density and anatomy - 17 species of tropical wood commercially available in Europe and Scots pine and European oak. The specimens were exposed to artificial weathering consisting of soaking wood in water, drying at 70 °C and exposure to UV radiation. Three-step aging cycle was repeated 140 times. In general, the tested wood species changed their compressive strength differently under the influence of artificial weathering. The process of artificial weathering caused a loss of strength of all tested wood species. The extent of changes depended on initial properties of wood (especially density) and anatomy. The changes were most pronounced at the beginning of the artificial weathering process.

ABSTRACT The aim of this research was to evaluate the effects of removing fines on the physical and mechanical properties of high-density particleboard produced by mechanical processing of Caryocar villosum (pequiá), Tachigali myrmecophyla (tachi-preto) and Hymenolobium excelsum (angelim-da-mata) Amazonian woods. The panels were produced with nominal density of 850 kg.m-3, thickness of 15.7 mm and phenol formaldehyde adhesive. The experimental design was arranged in a factorial design, with the assessment of the effects of three species (pequiá, tachi-preto and angelim-da-mata) and two particle classifications (with and without fines). Their performance was evaluated with respect to their physical (apparent density, moisture content, water absorption and thickness swelling) and mechanical (static bending – modulus of elasticity and modulus of rupture and internal bond) properties, realized according to ABNT NBR 14810-3. The removal of fines in the production of panels generated a tendency towards increased MoR, MoE and internal bond values and contributed to reductions in AAw2h, AAw24h and ST2h.

Timber from the second cutting cycle may make up the majority of future crop volumetric. However, there are few studies of the physical and mechanical properties of this timber, which are important to support the consolidation of new species. This study aimed to use Artificial Neural Networks to estimate the physical and mechanical properties of wood from the Amazon, based on basic density. The properties were: shrinkage (tangential, radial and volumetric), static bending, parallel and perpendicular to the fiber compression, parallel and transverse to the fibers, Janka hardness, traction, splitting and shear. The estimate followed the tendency of the data observed for the tangential, radial and volumetric shrinkage. The network estimated the mechanical properties with significant accuracy. Distribution of errors, static bending, parallel compression and perpendicular to the fiber compression also showed significant accuracy. Artificial Neural Networks can be used to estimate the physical and mechanical properties of wood from Amazon species.

Timber from the second cutting cycle may make up the majority of future crop volumetric. However, there are few studies of the physical and mechanical properties of this timber, which are important to support the consolidation of new species. This study aimed to use Artificial Neural Networks to estimate the physical and mechanical properties of wood from the Amazon, based on basic density. The properties were: shrinkage (tangential, radial and volumetric), static bending, parallel and perpendicular to the fiber compression, parallel and transverse to the fibers, Janka hardness, traction, splitting and shear. The estimate followed the tendency of the data observed for the tangential, radial and volumetric shrinkage. The network estimated the mechanical properties with significant accuracy. Distribution of errors, static bending, parallel compression and perpendicular to the fiber compression also showed significant accuracy. Artificial Neural Networks can be used to estimate the physical and mechanical properties of wood from Amazon species. [ABSTRACT FROM AUTHOR]

The main goal of this paper was to clarify to what extent extractives and wood structure determine the surface properties of hardwoods, mainly tropical. The role of wood extractives relative to properties, such as wettability and free surface energy, has been confirmed. The most significant seemed to be cyclohexane extractives. It was further found that in the case of tested tropical wood species, the extractives contents were high. Moreover the important role of axial parenchyma in wood wettability was established. It was established that multiple regression analysis could be useful in understanding wood properties as the result of the complex structure of wood. The obtained data is crucial from a practical point of view for its disclosure of those wood species that require surface modification prior to varnish coating. [ABSTRACT FROM AUTHOR]

Copyright of Wood Industry / Drvna Industrija is the property of Drvna Industrija and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Wood is a material widely used in various sectors of construction, such as in structures and building components. The volume of wood extracted from tropical forests has reached a considerable amount, and this wood is marketed with popular names without prior characterization. Wood density is an easy property to measure, and its use as an estimator of other properties is very common in this sector. This study investigated the possibility of the estimation of important quantities in dimensional stability of Brazilian tropical woods by using the density at 12% moisture content, anhydrous density, and basic density. Testing the ability to estimate radial, axial, tangential, and volumetric shrinkage, anisotropy coefficient, coefficient of volumetric rate of volumetric shrinkage, as well as the rate of volumetric swelling using the densities above, with linear, exponential, geometric, and logarithmic models, the best determination coefficient was: R2 = 19.58%. The results were, in summary, that the variable density was not a good estimator of the dimensional stability of the wood. [ABSTRACT FROM AUTHOR]

Bent trees have been observed during the early years in juvenile plantations (less than 5 years-old) of Tectona grandis in Costa Rica. The relationship between bending and the morphological characteristics of the trees was explored. An evaluation of bent trees was conducted in six juvenile plantations (8, 17, 27, 28, 31, and 54 months old) of Tectona grandis. Site 1 with 8-month-old plantations did not display any relationship with any tree morphological variable (diameter, height, and crown weight of tree), whereas for the sites 2, 3, and 4 with 17-, 27-, and 28-month-old plantations, respectively, all the tree morphological variables were statistically correlated with the bent trees. A multiple regression analysis showed that the most influential variables were height to crown base, crown weight, diameter, and total height of the tree. An evaluation of the bending risk factor (RF) was correlated with the height to crown base, crown weight, and form factor. The modulus of elasticity and chemical compositions of bent trees differed from those of straight trees. The causes of tree bending are complex, involving, among other factors, the morphology of the trees, plantation conditions, and other factors specific to the xylem, such as the specific gravity, modulus of elasticity, and presence of calcium and magnesium in the wood. [ABSTRACT FROM AUTHOR]

The main objective of this research was to investigate tropical wood sorptive properties. For selected tropical wood species (courbaril, ipe, light red meranti, merbau, tatajuba, and teak), the equilibrium moisture content was determined at 20 °C and 9, 30, 55, 70, and 97% relative humidity. The experimentally determined values were analysed using the Hailwood-Horrobin sorption model to compute the fibre saturation point and mono- and multi-layer sorption. There were significant differences in the sorption behaviour of different wood species. Generally, the fibre saturation point of tropical wood species is lower than in wood species from moderate climate zones. The lowest values of fibre saturation point were found for ipe (18.7%), courbaril (20.4%), and tatajuba (20.5%). Furthermore, chloroform-ethanol extractives content was correlated with multilayer sorption and the fibre saturation point, such that a higher content of chloroform-ethanol extractives was associated with a lower equilibrium moisture content. Therefore, chemisorption was not influenced by chloroform-ethanol extractives. Ethanol extracts showed an influence on monomolecular-bound water. [ABSTRACT FROM AUTHOR]

This paper aims to study the mechanical behavior and surface chemistry in relationship with moisture content of Iroko ( Milicia excelsa ), Bilinga (N auclea diderrichii ), and Tali ( Erythrophleum suaveolens ). Mechanical characterization was done experimentally using tensile and bending tests. Chemical semi quantitative analysis of the wood at 10%, 15%, 20% and 30% of moisture content was investigated using attenuated total reflectance Fourier transform infrared spectroscopy. The main chemical functions involved by the presence of water were identified as well as the other functional groups. The ratio between lignin and carbohydrates was estimated for all the wood species. The results indicated a negative correlation in the relation between moisture content and mechanical properties. Tali had the higher bending strength while Iroko had the lowest value. The average percentage change rate of the Young’s moduli induced by 1% of moisture content changes, especially between 10% and 20%, varied with the wood species: 1.69% in Tali, 1.65% in Bilinga and 2.54% in Iroko approximately. The infrared spectra obtained differed among species. The results also showed that Iroko contained higher lignin and were the least sustainable according to mechanical properties. The bands at 3340 cm −1 and 1635 cm −1 were more impacted by moisture content. [ABSTRACT FROM AUTHOR]

Objetivou-se avaliar o emprego de ensaios de dureza Rockwell na caracterização da biodeterioração das madeiras de Simarouba amara (marupá), Cariniana micrantha (jequitibá) e Dipteryx odorata (cumaru), submetidas ao ataque dos fungos apodrecedores Trametes versicolor (podridão branca) e Gloeophyllum trabeum (podridão parda). Para tanto, corpos de prova de cada espécie amazônica foram submetidos a ensaios de apodrecimento acelerado, de acordo com a ASTM D2017 (2005), durante 20 semanas. A caracterização da dureza Rockwell foi realizada semanalmente até a 4ª semana e, posteriormente, a cada duas semanas, até a 20ª semana. Adicionalmente, foram determinadas as perdas de massa, conforme critérios estabelecidos pela ASTM D2017 (2005). Quanto aos resultados, destaca-se que a dureza Rockwell pode ser empregada como ferramenta principal na caracterização da biodeterioração da madeira, sendo sensível na predição dos estágios iniciais. Dentre as madeiras amazônicas, o cumaru apresentou a maior resistência natural aos fungos apodrecedores. Com relação aos fungos, a podridão parda atacou mais intensamente as três madeiras amazônicas.This study aimed to evaluate the use of Rockwell hardness in the characterization of the biodeterioration of Simarouba amara (marupá), Cariniana micrantha (jequitibá) e Dipteryx odorata (cumaru) woods, which were submitted to decay fungi Trametes versicolor (white rot) and Gloeophyllum trabeum (brown rot). For this purpose, specimens of each Amazon species were submitted to decay fungi, according to ASTM D2017 (2005). The characterization of the Rockwell hardness was performed weekly until the fourth week, and then every two weeks until the twentieth week. Additionally, it was determined the mass loss, according to criteria established by ASTM D2017 (2005). The results indicated that the Rockwell hardness can be used as a primary tool in the characterization of the biodeterioration of wood, being sensitive in predicting the early stages. Among the Amazon woods, cumaru wood showed a greater natural resistance to decay fungi. With respect to decay fungi, brown rot more intensely attacked the three Amazon woods.

The objective of this paper was to evaluate the wood from Angelim Vermelho (Dinizia excelsa Duck) by means of nondestructive methods (transverse vibration, ultrasound and static bending) and also to determine the most suitable method to estimate static bendingmodulus of elasticity. Fifty structural beams from angelim vermelho were nondestructively evaluated and static bending modulus of elasticity (EM), transverse vibration (Edvt) and ultrasound stiffness coefficient (CLL) were calculated. Data was analyzed through linearsimple regression using Edvt and CLL as predictors of Em. The results pointed out that Edvt was the most suitable variable to estimate EM in comparison to CLL. It could be concluded that transverse vibration is recommended to grade wood from Dinizia excelsa Ducke, which presented good values of stiffness.

This paper aims to characterize the wood anatomy of Croton piptocalyx. To carry out an investigation of axial variation, discussing it in a functional context, helping to increase knowledge about the species. Five randomly selected 32-year-old trees were felled at the Luiz Antonio Experimental Station, located in Luiz Antonio City, São Paulo state, Brazil. From stems, discs were cut from six different stem heights (stem base, 1 m, 2 m, 3 m, 4 m, and 5 m). For each disc, samples close to the bark were removed for wood anatomy studies and specific gravity calculation. Wood anatomy of C. piptocalyx generally agrees with that of other species of the genus as described in the literature. However, variation in both quantitative and qualitative data could be related to tree age and species differences. Axial variations found in vessel element length, vessel diameter and ray height can be respectively related to the hypothesized Typical Radial Pattern based on the occurrence of shorter and narrower cells in younger parts of the wood, involving vessel element length and diameter, and mechanical requirement in the case of higher rays at the trunk base.

The heterogeneity of color distribution between sapwood and heartwood limits the market for wood from fast-growth plantations of tropical species. Wood color is associated with wood extractives contents. This study presents the relationship between wood color parameters measured by the CIELab color system and total amount of extractives and phenolic-type extractives in ethanol-toluene and hot water extracts of wood from two fast-growth plantation species. The results demonstrated that the difference in sapwood and hardwood color in Vochysia guatemalensis and Acacia mangium is caused by lower concentrations of extractives in sapwood of both species. Additionally, variations in total extractive and phenolic content have different effects on the color parameters (L*, a* and b*) of both species studied. In Vochysia guatemalensis wood, parameter L* decreases as total extractive and phenolic content increases; however, parameter a* increases as the content of extractives and phenols increases. In Acacia mangium, the amount of phenols showed no relationship with the color parameters. The ethanol-toluene total extractive content, however, shows a relationship with several color parameters. An increase in the content of total extractives in water and ethanol-toluene increases parameter a*, but decreases parameter L*.