Fabricio Gomes Gonçalves

Estudo de algumas propriedades mecânicas da madeira de um híbrido clonal de Eucalyptus urophylla X Eucalyptus grandis

The search for wood originated from reforestations destined to sawmill has been observed for many years, mainly for the Eucalyptus species. Searching for information to assist this market, the aim of this study was to determine some mechanical properties of the wood from a Eucalyptus urophylla x Eucalyptus grandis clonal hybrid, at two different ages and coming from coppice and reform. The results show that the wood of this clonal hybrid presents good technological characteristics and is the second best log (starting from 3,0 m), as to static bending properties (Module of Elasticity - MOE and Module of Rupture - MOR). The oldest trees (166 months - E2) which suffered two thinning presented the best results for the property of static bending and axial crushing (CA).

Influência da composição da resina tanino-uréia-formaldeído nas propriedades físicas e macânicas de chapas aglomeradas

In the production of the wood base particleboards, synthetic adhesives are used as melamina-formaldehyde (MF), phenol-formaldehyde (FF), urea-formaldehyde (UF), among others. Due to the high cost of these adhesives, researches that a seek the introduction of alterations in their formulations are important for the reduction of costs in the productive system. This work had as objective verify the influence of the several levels of Acacia mearnsii tannin in a commercial resin of urea-formaldehyde an the physical and mechanical properties of the particleboard. The particleboard was produced with Eucalyptus urophylla wood. They were four treatments: T1 - 100% of resin UF (control); (T2) 90% of the resin UF + 10% of the tannin 50%; (T3) 85% of the resin UF + 15% of the tannin 50% and (T4) 70% of the resin UF + 30% of the tannin 50%. The results showed that it is possible to add tannin to the resin urea-formaldehyde without to alter the physical and mechanical properties of the boards.

Densidade básica e variação dimensional de um híbrido clonal de Eucalyptus urophylla x Eucalyptus grandis

Fast growing species as those belonging to the gender Eucalyptus present serious problems during the various phases of sawing, drying and processing. Thus, this work aimed to study the physical wood properties of a clonal hybrid of Eucalyptus urophylla x Eucalyptus grandis at two ages originated from coppice and replacement regeneration at different thinning intensities, with diameters between 28.0 and 30.0 cm. The results showed that the extract of older aged wood with two thinning interventions (E2) presented the highest mean values for specific gravity along the stem and in the position pith to bark, as well as lower average volumetric contractions and lower average anisotropic factor (1.66). Although extract E1, with coppice at the age of 70 months and anisotropic factor equal to 1.92, was close to extract E3, with only one replacement at the age of 70 months and anisotropic factor equal to 2.04 along the stem, it presented the lowest specific gravity and average shrinkage values for log 1 in relation to log 2. The same behavior was verified for volumetric contraction. The anisotropy factor in log 1 was lower in relation to log 2 in extracts E1 and E3.

Comportamento de adesão da madeira de um híbrido clonal de Eucalyptus urophylla × Eucalyptus grandis proveniente de três condições de manejo

Univ Estadual Paulista, Programa Posgrad Ciencias Florestais, Fac Ciencias Agr, BR-18610307 Botucatu, SP, Brazil

Efeito da Concentração na Ascensão de Soluções Preservativas Preparadas com CCB em Moirões de Eucalyptus

The aim of this study was to verify the influence of concentration on ascension of preservative solutions in the treatment time of Eucalyptus urophylla x Eucalyptus grandis fence posts. The solutions were prepared with four concentrations of chromated copper borate - CCB, with 0.5; 1.0; 2.0; and 3.0% active ingredients. The sap displacement method by radial transpiration was employed, and five fence posts were treated for each concentration. The ascension times of the respective concentrations were of 8, 7, 5, and 3 days. Penetration was analyzed at four positions on fence posts and retention was analyzed at the position corresponding to the ground zone of installed fence posts. Boron and copper penetrations were satisfactory for the fence posts treated with 3.0% solution, and fence posts treated with 2.0% solution reached values close to those recommended by the Brazilian legislation. Retention in the samples of external disks reached the recommended values, except for the fence posts treated with 0.5% solution. Increased solution concentration caused a reduction in the treatment time of fence posts.

Efeito da Concentração na Ascensão de Soluções Preservativas Preparadas com CCB em Moirões de Eucalyptus / Effect of Concentration on Ascension of Preservative Solutions Prepared with CCB in Eucalyptus Fence Posts

The aim of this study was to verify the influence of concentration on ascension of preservative solutions in the treatment time of Eucalyptus urophylla x Eucalyptus grandis fence posts. The solutions were prepared with four concentrations of chromated copper borate - CCB, with 0.5; 1.0; 2.0; and 3.0% active ingredients. The sap displacement method by radial transpiration was employed, and five fence posts were treated for each concentration. The ascension times of the respective concentrations were of 8, 7, 5, and 3 days. Penetration was analyzed at four positions on fence posts and retention was analyzed at the position corresponding to the ground zone of installed fence posts. Boron and copper penetrations were satisfactory for the fence posts treated with 3.0% solution, and fence posts treated with 2.0% solution reached values close to those recommended by the Brazilian legislation. Retention in the samples of external disks reached the recommended values, except for the fence posts treated with 0.5% solution. Increased solution concentration caused a reduction in the treatment time of fence posts.

CHAPAS AGLOMERADAS CONFECCIONADAS COM UREIA-FORMALDEÍDO SOB ADIÇÃO DE TANINO EM PÓ

This work aimed to evaluate the technological properties of particleboards manufactured with particles of Acacia mangium and urea-formaldehyde adhesive by addition of powder form commercial tannin of Acacia mearnsii to their particles. The boards manufactured under different compaction ratio and the effect of these in the properties of the boards evaluated. It used a completely randomized design in the factorial outline 4 x 4 as follows: four percentages of substitution of powder form tannin to the adhesive urea-formaldehyde - 0, 10, 20 and 30%; and four nominal compaction ratios: 1.39, 1.55, 1.73, and 2.00. The pressing cycle used was 3.92 specific pressure with temperature of 140oC by 8 minutes. The addition of powder tannin to particles with urea-formaldehyde provided some improvements in the physical and mechanical properties. The results indicate that the addition of tannin powder is a viable alternative of use in particleboards, with no need for dilution.

EMERGÊNCIA E QUALIDADE DE MUDAS DE Enterolobium contortisiliquum (Vell.) Morong (Fabaceae) EM DIFERENTES SUBSTRATOS

The present study aimed to evaluate the influence of different materials in the emergency and growth of Enterolobium contortisiliquum seedlings. Distinct substrates were formulated using vermiculite, charcoal wastes, subsoil, organic compost and wood sawdust, consisting of 16 treatments. The variables emergency, speed index and average time of emergency, total height of the plant, length of the root, length of the stem, root collar diameter, number of nodules, root and stem dry mass, root volume, and the Dickson Quality Index, were analyzed during 120 days. Almost all the substrates provided satisfactory results, especially the treatments with 50% of vermiculite, 50% of organic compost and the treatment with 33% vermiculite, 33% charcoal wastes and 33% organic compost.

DENSITOMETRIA DE RAIOS X NA AVALIAÇÃO DA DENSIDADE EM PAINÉIS DE PARTÍCULAS

This study aimed to determine the apparent density, by gravimetric technique and X-ray microdensitometry of particleboard produced with Acacia mangium wood and search existence of correlation between both methods. It was used urea formaldehyde adhesive and commercial tannin Acacia mearnsii applied in powder form directly to the previously glued particles. The panels manufactured using four compression ratios (1.39, 1.55, 1.73, and 2.00) combined four levels of powdered tannin (0, 10, 20 and 30%), making up 16 treatments (4 panels by treatment). The particleboard apparent density parameters (mean, maximum and minimum) and gravimetric density were determined, analyzed and compared. The density profile presented graphically and interpreted by analysis of variance and multiple linear regression. The apparent density, medium, maximum and minimum for particleboard obtained by microdensitometry X-ray ranged 357-697 kg/m 3 , 386-824 kg/m 3 , and 334-634 kg/m 3 , respectively, and gravimetric method 369-742 kg/m 3 . The technique was effective in determining variations in the density profile in the thickness of the particleboards in all treatments, as well as direct obtain the apparent density. These variations could be reduced if the tannin used was previously hydrated in water. Was found strong correlation (R 2 = 0.99) between the mean apparent density obtained by X-ray microdensitometer and gravimetric method.

VARIAÇÃO DOS MÓDULOS DE ELASTICIDADE E RUPTURA EM MADEIRA DE CEDRO-AUSTRALIANO POR MEIO DE ENSAIOS NÃO DESTRUTIVO E DESTRUTIVO

The elastic of modulus is an important mechanical property in the design of timber structures, so obtaining it through several methods needs to be evaluated. This study aimed to evaluate the use of an efficient technique for determining the apparent longitudinal modulus taking into account the relationship range/height ( L/h ) and the influence of the shear modulus by comparing non-destructive tests with static bending tests. The wood used in paper was Toona ciliata M. Roemer (Australian cedar). Non-destructive tests were performed with the techniques of longitudinal and transverse vibration. It was concluded that the assay of longitudinal vibration is most suitable method to obtain the apparent longitudinal elasticity modulus, because the shear forces that occur due to the shear stresses are not significantly influenced by the variations of the ratio L/h . It was also possible to conclude that the relationship range/height, currently 21 in ABNT’s standards, may be replaced by 20, when determining apparent longitudinal elasticity modules and modulus of rupture, through the static bending and free transverse vibration tests.