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    Changes in surface and mechanical properties of heat treated wood during natural weathering
    (Elsevier Sci Ltd, 2014) Dizman Tomak, Eylem; Ustaomer, Derya; Yildiz, Sibel; Pesman, Emrah
    In this study, it was aimed to investigate the changes in moisture content, color, surface roughness, compression strength parallel to grain, modulus of rupture and modulus of elasticity of heat treated ash, iroko, Scots pine and spruce wood species during natural weathering for two years. Samples were removed at 6-month intervals for performance evaluation, and test results were compared with the controls. Moisture content of heat treated samples was found to be lower than that of control samples for all exposure periods. Heat treatment significantly changed original wood color as well as weathering factors. Wood surfaces become rougher within longer weathering exposure period. Natural weathering factors caused a decrease for all strength properties. Reduction rate for strength properties of heat treated samples was relatively lower than that of control samples. Heat treatment also seemed to improve color stability and surface quality of samples after weathering. (C) 2014 Elsevier Ltd. All rights reserved.
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    Effects of Flotation Deinking on the Removal of Main Colors of Oil-Based Inks from Uncoated and Coated Office Papers
    (North Carolina State Univ Dept Wood & Paper Sci, 2013) İmamoğlu, Sami; Karademir, Arif; Pesman, Emrah; Aydemir, Cem; Atik, Celil
    This paper presents the results of trials to evaluate the color-stripping behaviour of offset printing colors and the effect of coating on deinking performance. Oil-based four-color inks were separately printed as base printing on coated and uncoated white poster paper, and then extensive pulping and deinking processes were carried out. Standard offset printings were conducted on paper samples using cyan, magenta, yellow, and black colors (CMYK), and the effects of deinking efficiency on the removal of each color were analysed. The pulps were made at Micro-Maelstrom Laboratory Pulper at specified conditions with and without bleaching agents. Formamidin sulfinic acid and hydrogen peroxide formulation were used as reductive and oxidative bleaching agents, respectively. Flotation deinking and thickening of pulp were practiced using Degussa flotation and thickening cell. The changes in the optical properties, such as brightness, whiteness, and color value (CIE L*, a*b*) of deinked pulp were determined. It was found that optical properties of color-stripped pulps from coated papers were better than that of uncoated office papers. However, yield was quite low in coated papers since fillers were lost during flotation process. Cyan color was found to be the most difficult one in four main color printing inks stripping out in deinking process.
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    SURFACE PROPERTIES OF BAMBOO AND SCOTS PINE IMPREGNATED WITH BORON AND COPPER BASED WOOD PRESERVATIVES AFTER ACCELERATED WEATHERING
    (Univ Bio-Bio, 2016) Baysal, Ergun; Dizman Tomak, Eylem; Topaloglu, Elif; Pesman, Emrah
    In this study, we investigated the color, gloss and surface roughness of bamboo (Phyllostachys bambusoides) and Scots pine (Pinus sylvestris) samples impregnated with boron and copper based preservatives during accelerated weathering from 168 h to 672 h. Tanalith-E, ACQ, wolmanit-CB were used as copper-based chemicals, while a mixture of boric acid and borax (7:3; w/w) was used as the boron compound. Results showed that retention values of bamboo samples were lower than the retention values of Scots pine samples probably due to the bamboo's anatomical structure and penetration characteristic. Bamboo surfaces became rougher and darker after impregnation and accelerated weathering compared to initial surfaces. Longer accelerated weathering periods seemed to have not a considerable effect on surface roughness of bamboo samples impregnated with copper based preservatives. Gloss of impregnated Scots pine samples increased with longer accelerated weathering period while gloss of bamboo samples decreased slightly with longer accelerated weathering period. Wolmanit-CB seemed to be most effective wood preservative for hindering color change and ensuring smooth surfaces after accelerated weathering. Color changes caused by accelerated weathering tended to be greater for impregnated bamboo samples than impregnated Scots pine samples.