Recovery Of Set Research Articles

Densified wood anatomical structure and the effect of heat treatment on the recovery of set

Densification of wood is a method to improve wood quality. However, its product namely densified wood, tends to return to the initial shape and size (spring back) if the fixation had not completed. This method will also result in the changes on wood anatomy structure. The aim of this research was to assess effect of various densification degrees at radial direction on recovery of set (RS) and anatomical structure of wood of Agathis loranthifolia Salisb and Gmelina Arborea Roxb. The result showed that heating at 180 °C resulted in the decreasing of RS wood densified. Cell woods namely tracheid, fiber and ray parenchyma on the surface became more flat and buckle compared to those at the center. Flat and buckle produced an S-shape in cell wall structure. Densified wood perfectly fixed yet after being given a heat treatment at a temperature of 180 °C up to 24 h.

Fixation of Soft-inner Part of Oil Palm Trunk by Close System Compression Method

Compression by closes system compression (CSC) improved quality of the soft-inner part of oil palm trunk (S-OPT). The problem of compressed-wood was spring back or recovery of set, if it was exposed to moisture content. The objective of these study were to evaluate the recovery of set (RS) and weight loss (WL) of S-OPT by CSC. These methods were compared with heat treatment (HT) and steam treatment (ST). Density of S-OPT was 0.3 g/cm3. All samples were compressed to compression ratio of 50%. The compression of HT method used the temperatur of 120, 140, 160, 180 and 200 °C for 0, 10, 30, 60 and 180 minutes; and ST method used temperature of 120, 140, 160, 170 and 180 °C for 0, 5, 10 and 30 minute; while CSC method used temperature of 120, 140, 160, 180 and 200 °C for 0, 10, 20, 30 and 40 minutes. The results showed that the temperature and compression time contributed to the RS and WL value for all methods. Increasing compression temperature and time leads to decreased the RS value and to increased the WL value. The lower RS value indicated that S-OPT fixation would be better or high dimensional stability. Fixation of S-OPT by ST method was achieved at temperature of 170 °C for 30 min, CSC at temperature of 180 °C for 30 min, while HT method has not fixated until 200 °C for 180 min.

Quality Improvement of Oil Palm Trunk Properties by Close System Compression Method

ABSTRACT Densification of the inner part of oil palm trunk (OPT) by the close system compression (CSC) method was performed in this study. The effects of the compression temperature and time on the anatomical, physical and mechanical properties of OPT were evaluated. The inner part of OPT with an initial average density of 0.3 g/cm 3 was used as samples. Oven-dried samples were immersed in water and vacuumed until fully saturated andthen compressed by CSC at 120, 140, 160 or 180℃ for 10, 20, 30 or 40 min. The anatomical characteristics of transverse and radial sections before and after compression were compared by optical microscopy. The phys-ical and mechanical properties, including the density, recovery of set (RS), modulus of elasticity (MOE), mod-ulus of rupture (MOR), and compression parallel to grain were examined. It was observed that the anatomical characteristic of the inner part of OPT (i.e., vascular bundles, vessels, and parenchyma tissue) became flattened,fractured, and collapsed after compression by CSC. The RS decreased with increasing compression temperatureand time. The lower RS indicated high dimensional stability. The physical and mechanical properties (i.e., den-sity, MOR, MOE, and compressive strength) of the inner part of OPT increased with increasing compression temperature and time. Compression by the CSC method at 160℃ for 40 min was the optimum treatment. Keywords : close system compression, compressed wood, oil palm trunk, physical and mechanical properties, recovery of set