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Drill feed speed significantly affects the measurement accuracy and efficiency of the micro drill resistance instrument. Generally, different speeds are set according to the density of the wood to be drilled. It is necessary to convert the resistance data measured at different drill feed speeds into resistance data at a uniform speed to properly analyze resistance data. In this study, drill resistance data for a Paulownia wood block was measured with a self-made micro drill resistance instrument at different drill feed speeds. We found that the drill resistance is positively correlated with changes in its feed speed and the natural logarithm of change times for feed speed. We developed a conversion algorithm for the micro drill resistance instrument measurements at different feed speeds. The accuracy of the conversion algorithm is up to 95%. The algorithm can be used to convert the drill resistance of Paulownia wood measured at different drill feed speeds; it has reference value for the mutual conversion of other tree species' drill resistance data measured at different feed speeds. This work may provide a feasible solution to improving micro drill resistance instrument accuracy when drill feed speed error is high. [ABSTRACT FROM AUTHOR]

Wood sponges obtained by structure-retaining delignification of natural wood sheets are promising for CO2 storage. Herein, lignin in balsa wood is selectively removed through chemical treatment, leading to a highly porous structure. To boost the CO2 adsorption capacity, amine agents are grafted on the delignified wood via a condensation reaction. The resulting amine-grafted wood sponges exhibit hierarchical porosity and are mechanically resilient. A relatively high CO2 uptake of 1.22 mmol g−1 (25 °C, 1 bar) is achieved due to the physisorption of hierarchical pores and chemisorption of high amine group loading. Such amine-grafted wood sponges fabricated from top-down strategy hold great potential to serve as renewable CO2 capture materials. [ABSTRACT FROM AUTHOR]