Search

As an important oil crop in China and the world, the harvesting problem of Camellia oleifera has attracted much attention. Research is needed on mechanical characteristics of harvesting equipment. Explicit dynamics was used to establish a finite element model under a simulated load response to the branch-pedicel-fruit system of C. oleifera to predict the fracture process at the pedicel junction. The separation mechanism of C. oleifera fruit was determined by measuring the constitutive parameters of fruit branches and pedicels and conducting separation experiments and explicit dynamics simulations on different hanging fruits. The maximum stress at the fruit pedicel was 1.14 MPa, and the goodness of fit between the simulation and experiment was approximately 89.5%, indicating that the branch-pedicel-fruit finite element model could accurately reflect the fruit shedding process and that the pedicel diameter was correlated positively with the separation force. This study provides technical parameters for the optimized design of existing C. oleifera harvesting equipment. [ABSTRACT FROM AUTHOR]

High-frequency electromagnetic fields refer to electromagnetic waves with frequencies ranging from 100 kHz to 300 MHz. High-frequency medium heating has the advantages of uniform heating, rapid energy consumption, and environmental protection. While it has a wide range of applications, the use of high-frequency dielectric heating in the bamboo industry is rare. Understanding the influence of bamboo temperature rise rate in highfrequency heating could promote bamboo industry development. In this work, curved bamboo was tested with high-temperature energy for continuous heating. The influence of moisture content of bamboo, sample thickness, and high-frequency processing power on temperature rise rate were studied. The results showed that the water content of bamboo affected the temperature rise rate. The effect of high-frequency heating was highest when the moisture content of bamboo was close to 11%. The thickness of sample had little effect on the temperature rise rate, but the high-frequency power had a significant effect on the temperature rise rate. The temperature rise rate of the lower and higher frequency power levels increased slowly and was close to constant. The heating power was 11 kW, and the temperature rise rate was the highest. [ABSTRACT FROM AUTHOR]

Using bamboo to replace wood has great significance for the protection of forests. This work presents the concept of the reorganization of arc bamboo sheet to produce recombined arc-segment bamboo lumber (RABL). Several key preparation technology parameters were investigated. Results showed that when the phenol resin (PF) doublesided adhesive quantity was 250 g/m², unit pressure was 2.0 MPa, screen voltage was 4200 V, screen current was 1.5 A, and hot pressing time was 30 s/mm, the modulus of rupture (MOR) of the RABL was 105 MPa and the modulus of elasticity (MOE) was 5000 MPa. These parameters mean that RABL could be used as the structural material for load-bearing situations. If ignoring the machining allowance, the bamboo utilization rate of the RABL was 1.72 times that of the rectangular element recombinant bamboo and the adhesive level of the RABL was 0.6 times that of the rectangular element recombinant bamboo. When considering the machining allowance, the bamboo utilization rate of the RABL was 1.8 times that of the rectangular element recombinant bamboo, and the adhesive volume of the RABL was 0.56 times that of the rectangular element recombinant bamboo, so RABL has obvious advantages. [ABSTRACT FROM AUTHOR]

With the increasing scarcity of wood as a natural resource, bamboo has become a popular substitute for wood. The present work developed a high-strength original state multi-reorganization material (GPEHB), without the use of a hot press or traditional assembly. The original bamboo units were polygonized into outer contours and milled into finger-joints on each ending. The GPEHB was organized and assembled under an external press, using industrial adhesives. The mechanical properties and thermal insulation of GPEHB were characterized. Moreover, the overall GPEHB unit bending strength was 73.15 MPa, and the parallel-to-grain compression was 55.22 MPa (higher than that of Pinus sylvestris lumber, though less than that of glued laminated bamboo). The GPEHB unit overall density was 0.24 g/cm³, 76% lower than that of glued laminated bamboo, and 50% lower than Pinus sylvestris lumber. The compressive strength of GPEHB (7 units) was 170.5 kN, while the compressive strength of GPEHB for 14 units was 493.5 kN, which meet the requirements of GB 50005 (2003). The bending strength of GPEHB 7 units was 12 kN, while that of 14 units was 37 kN. The heat conductivity coefficient for GPEHB was 0.25 W/mK, which is better than concrete and steel. The GPEHB has taken full advantage of its honeycomb-structured material, which allows it to avoid stress concentration in the regular polygonal corners. [ABSTRACT FROM AUTHOR]