Luciano Donizeti Varanda

Tenacidade da madeira como função da densidade aparente

The knowledge on the behavior of wood in situations of short load contributes to the development of a safer structural design. However, toughness is not part of the mechanical properties commonly investigated in the characterization of this material. Therefore, the present study aimed to evaluate, the possibility to estimate the toughness with the knowledge of the apparent density of 6 Brazilian tropical wooden species (Angico, Eucalyptus, Jatoba, Parica, Pine and Teak), by using linear, quadratic and cubic polynomial regression models. The results highlighted the significance and representation of all adjustments investigated, and the cubic polynomial was the most efficient for estimating the wood toughness.

Oat hulls as addition to high density panels production

Wood panels manufacture show advantages of possibility to use alternative raw materials, as agro-industrial waste. Such products have increasing their importance, representativeness and use around the world, including Brazil, stimulated by the economic and environmental benefits of natural and renewable raw materials.Considering wood-based panels from reconstituted wood, particleboard can be highlighted because it is the most consumed and produced worldwide (Brazilian Association of Wood Panels Industry – ABIPA)

Life Cycle Assessment of Urea Formaldehyde Resin: Comparison by CML (2001), EDIP (1997) and USEtox (2008) Methods for Toxicological Impact Categories

This paper presents a Life Cycle Assessment comparison using CML (2001), EDIP (1997) and USETox (2008) methods for the impact assessment of urea formaldehyde resin (UF) used in the production of wood panels in Brazil. The impact results were focused just on toxicological categories like human toxicity and ecotoxicity. The main hotspots of UF resin were free formaldehyde air emissions to aquatic and terrestrial ecotoxicity and for human toxicity category, the results showed that emissions to air of nitrogen oxides from urea (raw material) are also very important and not just free formaldehyde air emissions like previously checked in literature.

Particleboard Produced with Sawmill Waste of Different Wood Species

This study aimed to investigate physical performance of particleboards produced with waste from sawmills, containing different wood species, and two adhesives: urea-formaldehyde (UF) based resin and castor-oil (PU) based bi-component polyurethane resin. Panels were produced with nominal density 0.8gcm-3; pressing temperature 110°C; pressing time 10 min; specific pressure 5 MPa. Water absorption (2 and 24h); thickness swelling (2 and 24h); density; and moisture content were investigated. Results confirmed that the produced panels presented compatible physical properties in comparison with other researches referred in literature, proving the feasibility of inputs employed. Panels produced PU showed better performance than those produced with UF.

Comparação entre valores de ensaios experimentais e calculados da resistência ao embutimento da madeira de Pinus taeda L.

To design connections between timber parts with metal dowels (nails or bolts), two phenomena must be considered: bending of the metal dowel and the embedment strength in the wood. The Brazilian Standard ABNT NBR 7190:1997 proposes the methods used in the laboratory tests to determine the embedment strength with the metal dowell and, in the absence of testing, specifies relations to calculate the embedment strength from the compression strength. The aim of this research was to compare the embedment strength values obtained by experimental tests and calculated by the relationships established by the Brazilian Standard ABNT NBR 7190:1997. By the results of the hypothesis tests, it was possible to conclude that the estimate of the embedment strength parallel to the grain proposed by the Brazilian standard ABNT NBR 7190:1997, establishing equivalence with the strength compression results in the same direction, must be effective to the wood species Pinus taeda L., however, the same was not found in the perpendicular direction with respect to the grain, possibly explained by the αe values in the equation to calculed fe90.