Study On Density And Moisture Detection Of Wood And Bamboo Based On X-ray Imaging Technology

Wood and bamboo resources are the important resources in the production and living of society. As a result of over-logging, wood and bamboo resources have dropped precipitously for years. The supply far cannot meet people’actual needs. Therefore, to improve resources utilization efficiency of wood and bamboo is an effective way to alleviate the contradiction. The non-destructive testing technology is one of effective methods to improve resources utilization efficiency of wood and bamboo. With the promotion of industrial production efficiency, the non-destructive testing technology has developed quickly. Because of its unique advantages, X-ray imaging technology was widely concerned by people. Based on these, Chinese white poplar, Masson pine and Moso bamboo were used as experimental materials to study the density and moisture content of wood and bamboo materials on the macroscopic and mesoscopic scale by using X-ray computed tomography technology and synchrotron radiation X-ray phase contrast microscopy imaging technology. We expect to provide the scientific basis and the data references to further research the industrial application about X-ray computed tomography technology and basic data to explain the mechanism of moisture transfer on the mesoscopic scale by using synchrotron radiation X-ray phase contrast microscopy imaging technology.In this paper the primary research results are as follows:(1)The heartwood and sapwood of Chinese white poplar and Masson pine were used as experimental materials to establish that (1)the’Density-CT value’fitting model is: D=kxH+b; (2)and the’Moisture content-CT value’fitting model is by combining physical measurement with X-ray computed tomography technology. Through validation test, the relative error was less than 5% which proves that the’Density-CT value’and’Moisture content-CT value’fitting models can predict accurately the density and moisture content of the heartwood and sapwood.(2)The differently aged Moso bamboo of were used as experimental materials to establish that (1)the’Density-CT value’fitting model is:DB= k x HB+b; (2)and the ’Moisture content-CT value’fitting model is:MB= k×HB+b by combining physical measurement with X-ray computed tomography technology. Through validation test, the relative error was less than 5% which proves that the’Density-CT value’and the ’Moisture content-CT value’fitting models can predict accurately the density and moisture content of the differently aged Moso bamboo.(3)The slices of Chinese white poplar and Masson pine were used as experimental materials to observe and analyze the free-absorbing and heat-losing moisture process on the mesoscopic scale by using synchrotron radiation X-ray phase contrast microscopy imaging technology:①Thtough observation and analysis, the capillary tube tension of the vessel of Chinese white poplar was larger than the tracheid of Masson pine. And this made that the free-absorbing moisture rate along the vessel direction of Chinese white poplar was larger than along the tracheid direction of Masson pine.②Because the types of cells on Chinese white poplar and Masson pine and the number and types of pits on the cell wall are different, the free-absorbing moisture rate across the vessel direction of Chinese white poplar was larger than across the tracheid direction of Masson pine.③The moisture permeability velocity along the capillary tube direction of Chinese white poplar and Masson pine was consistent with along the pits on the cell, which was affected by factors of the capillary tube tension, the air resistance, etc.④Because the specific surface area of the slices is larger, the copious amounts of water was evaporated from the surfaces. And the capillary tube tension of the vessel and he tracheid was not obvious, so the heat-losing moisture rate was basically consistent.⑤Because the capillary tube tension played a stimulating role in heat-losing moisture process to promote the moisture loss, the heat-losing moisture rate along the capillary tube direction of Chinese white poplar and Masson pine was larger than across the capillary tube direction.