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Official Journal of the Japan Wood Research Society

Journal of Wood Science Cover Image

Table 1 Density profile characteristics of sandwich compressed wood formed under different preheating conditions

From: Effects of preheating temperature, preheating time and their interaction on the sandwich structure formation and density profile of sandwich compressed wood

Preheating parameters Mean density of wood (g/cm3) Mean density of sandwich compressed wood (g/cm3) The characteristic parameters of compressed layer
Time (min) Temperature (°C) Number Thickness (mm) Mean density (g/cm3) Maximum density (g/cm3)
4 75 0.439 (0.028) 0.537 (0.030) 2 7.52 (0.48) 0.666 (0.026) 0.771 (0.232)
90 0.432 (0.026) 0.550 (0.038) 2 8.56 (0.97) 0.674 (0.032) 0.773 (0.056)
105 0.423 (0.022) 0.531 (0.032) 2 8.68 (1.18) 0.658 (0.037) 0.768 (0.061)
120 0.434 (0.021) 0.564 (0.043) 2 7.86 (0.66) 0.685 (0.038) 0.802 (0.053)
135 0.452 (0.020) 0.549 (0.026) 2 7.78 (0.66) 0.664 (0.027) 0.747 (0.036)
150 0.442 (0.024) 0.539 (0.029) 2 7.45 (0.44) 0.653 (0.017) 0.751 (0.025)
165 0.457 (0.027) 0.539 (0.016) 1 10.30 (0.09) 0.609 (0.036) 0.688 (0.030)
180 0.423 (0.027) 0.516 (0.035) 1 10.21 (0.46) 0.613 (0.038) 0.702 (0.056)
195 0.439 (0.030) 0.536 (0.043) 1 9.70 (0.72) 0.627 (0.043) 0.713 (0.031)
210 0.417 (0.021) 0.511 (0.025) 1 9.36 (0.58) 0.575 (0.043) 0.689 (0.017)
8 75 0.422 (0.023) 0.554 (0.034) 2 8.99 (0.83) 0.665 (0.028) 0.760 (0.033)
90 0.435 (0.009) 0.556 (0.025) 2 9.23 (0.78) 0.660 (0.023) 0.761 (0.033)
105 0.441 (0.008) 0.567 (0.033) 2 8.61 (1.10) 0.684 (0.025) 0.782 (0.043)
120 0.426 (0.024) 0.537 (0.035) 2 9.23 (0.83) 0.642 (0.020) 0.741 (0.032)
135 0.431 (0.026) 0.538 (0.032) 2 8.22 (0.36) 0.619 (0.030) 0.695 (0.035)
150 0.426 (0.017) 0.519 (0.024) 1 8.06 (1.20) 0.618 (0.017) 0.688 (0.040)
165 0.442 (0.035) 0.531 (0.026) 1 8.11 (1.16) 0.64 (0.027) 0.689 (0.034)
180 0.427 (0.011) 0.517 (0.026) 1 7.51 (0.96) 0.652 (0.016) 0.718 (0.023)
195 0.436 (0.022) 0.515 (0.024) 1 5.25 (1.04) 0.632 (0.029) 0.718 (0.043)
210 0.454 (0.041) 0.542 (0.038) 3 4.67 (0.79) 0.627 (0.044) 0.703 (0.035)
12 75 0.423 (0.026) 0.537 (0.049) 2 9.28 (0.82) 0.640 (0.026) 0.725 (0.051)
90 0.427 (0.016) 0.557 (0.018) 2 10.21 (0.43) 0.654 (0.020) 0.758 (0.026)
105 0.443 (0.029) 0.554 (0.033) 2 9.17 (0.64) 0.661 (0.030) 0.760 (0.045)
120 0.432 (0.015) 0.547 (0.034) 2 10.75 (1.44) 0.626 (0.017) 0.695 (0.038)
135 0.439 (0.025) 0.530 (0.025) 1 8.83 (0.41) 0.610 (0.034) 0.697 (0.034)
150 0.451 (0.039) 0.543 (0.043) 1 7.97 (0.72) 0.647 (0.047) 0.687 (0.047)
165 0.438 (0.025) 0.516 (0.023) 1 5.56 (0.94) 0.628 (0.028) 0.707 (0.033)
180 0.433 (0.021) 0.518 (0.028) 1 5.18 (0.72) 0.600 (0.071) 0.666 (0.071)
195 0.448 (0.026) 0.534 (0.040) 3 3.76 (1.27) 0.599 (0.021) 0.669 (0.024)
210 0.447 (0.047) 0.511 (0.051) 3 3.12 (0.15) 0.565 (0.043) 0.588 (0.035)
  1. Each value in parenthesis is standard deviation of six specimens; italic emphasizes preheating at 135 °C for 12 min, 150 °C for 8 min, and 165 °C for 4 min are conditions for the convergence of the compressed layers; when there are three compressed layers, the thickness, mean density, and maximum density of the compressed layer are the results of the central compressed layer