EFFECT OF ARTIFICIAL WEATHERING ON PHYSICAL AND MECHANICAL PROPERTIES OF WOOD

André Luis Christoforo,Tiago Hendrigo Almeida,Diego Henrique Almeida,Cesar Augusto Galvão De Morais,Francisco Antonio Rocco Lahr,Vinicius Borges De Moura Aquino,Marilia Silva Bertolini

doi:10.1590/1806-908820210000034

Abstract

ABSTRACT When wood is exposed outdoors, a combination of chemical and mechanical factors and solar radiation contribute to what is described as weathering, being the main degradation agent in this environment. This paper aims to investigate the effect of artificial weathering on mechanical and physical properties of Eucalyptus sp. and Cupiúba (Goupia glabra) woods simulating natural weathering effects. Samples were aged in UV radiation chamber with humidity and temperature control for 100, 200, 300 and 400 hours, considering aging cycles according to ASTM G154 (2006). Wood properties investigated were Conventional value of strength in static bending (fM), Modulus of elasticity in static bending (EM), strength in compression parallel to grain (fc0) and Janka Hardness (fH) according to ABNT NBT 7190 (1997). Effects of artificial weathering on wood properties were evaluated by statistical analysis at 5% significance level. Most of the wood properties investigated did not present significant changes with the aging performed, however, it was noted a decrease in the absolute values of the wood properties absolute values during the aging process. Only fH of Cupiúba wood aged for 100 and 200 hours presented significative performance loss at the significance level considered, which can be related to changes on the wood surface due to weathering exposure.

Highlights

Substrate formulation in seedlings production must ensure their physical and chemical quality
The present study aims to assess the quality of moringa grown in substrate produced from sugarcane bagasse associated with compost or vermicompost in different-volume tubes
The study followed a randomized blocks design, at 2x7 factorial arrangement, namely: tubes’ volumes (50 and 240 mL) x seven substrates (commercial substrate; sugarcane bagasse associated with urban waste compost at three different ratios (1:3; 1:1 and 3:1) and sugarcane bagasse associated with vermicompost at ratios 1:3; 1:1 and 3:1)

Summary

Introduction

Substrate formulation in seedlings production must ensure their physical and chemical quality. Besides providing the necessary nutrients for seedlings’ development, substrate must be wellaggregated by the root at the time to remove the seedling from the container, before its planting to protect it from impacts or from drying. Moringa leaves can be offered in the diet of milk cattle as protein supplementation, mainly during drought periods throughout the year, to replace part of the sugarcane (Lisita et al, 2018). Cultivation in arid and semiarid regions is recommended, since moringa’s tuberous roots are highly capable of absorbing and accumulating groundwater and underground mineral salts. This process allows plants to remain green all year long and survive in times of drought (Ndubuaku et al, 2014)

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