The composite board industry in Iran is obliged to use residues from forest operation as well as wood industry for competing with paper industry because of shortage of wood. In the present study we investigated the re...The composite board industry in Iran is obliged to use residues from forest operation as well as wood industry for competing with paper industry because of shortage of wood. In the present study we investigated the residues from poplar plantation used for particleboard production. Three kinds of wood materials, poplar branches, small di- ameter poplar wood （3-8 cm） and beech wood, were used in the experiment of particleboard production. The results demonstrated that the characteristic of particleboard made from poplar branches and small diameter wood is comparable to that made from mature beech wood. To avoid too much residual acid in the final board, the properties of boards produced with 1.5% hardener at 175℃ press temperature are acceptable, although the properties of particleboard produced with 2% hardener were higher than were higher than that of the board produced with lower hardener （1% or 1.5%）.. The MOR, MOE and IB of particleboard made from branches were measured as 14.57, 2015, and 1.32 MPa, respectively, while The MOR, MOE and IB of particleboard produced from small diameter poplar wood were 19.90, 2199, and 1.86 MPa, respectively. The thickness swelling of boards made from branches after 2 and 24 h im- mersion in water was 20.14% and 31.26%. The utilization of branches and very small diameter wood of poplar is recommended for the survival and developments of particleboard industry in Iran.展开更多
This paper focuses on the results of experimental work on workability and compressive strength of self-compacting concrete （SCC）. The work concentrated on concrete mixes having water/binder ratios of 0.45 and 0.35, ...This paper focuses on the results of experimental work on workability and compressive strength of self-compacting concrete （SCC）. The work concentrated on concrete mixes having water/binder ratios of 0.45 and 0.35, which contained constant total binder contents of 400 kg/m^3 and 500 kg/m^3, respectively. Based on the experimental results, the existing suggestions for anticipating the long-term compressive strength of SCC according to its compressive strength at the age of 7 days were not exact enough. Therefore, it is decided to use artificial neural networks （ANN） for predicting the long-term compressive strength of SCC from its workability and short-term compressive strength. For predicting the long-term compressive strength of SCC utilizing ANN, multi layer perceptron （MLP） networks and radial basis function （RBF） networks were chosen. The conclusion was that the MLP networks could properly predict the long-term compressive strength in all conditions, but RBF networks were not exact enough in some circumstances. On the other hand, RBF networks were more users friendly and they converged to the final networks quicker.展开更多
文摘The composite board industry in Iran is obliged to use residues from forest operation as well as wood industry for competing with paper industry because of shortage of wood. In the present study we investigated the residues from poplar plantation used for particleboard production. Three kinds of wood materials, poplar branches, small di- ameter poplar wood （3-8 cm） and beech wood, were used in the experiment of particleboard production. The results demonstrated that the characteristic of particleboard made from poplar branches and small diameter wood is comparable to that made from mature beech wood. To avoid too much residual acid in the final board, the properties of boards produced with 1.5% hardener at 175℃ press temperature are acceptable, although the properties of particleboard produced with 2% hardener were higher than were higher than that of the board produced with lower hardener （1% or 1.5%）.. The MOR, MOE and IB of particleboard made from branches were measured as 14.57, 2015, and 1.32 MPa, respectively, while The MOR, MOE and IB of particleboard produced from small diameter poplar wood were 19.90, 2199, and 1.86 MPa, respectively. The thickness swelling of boards made from branches after 2 and 24 h im- mersion in water was 20.14% and 31.26%. The utilization of branches and very small diameter wood of poplar is recommended for the survival and developments of particleboard industry in Iran.
文摘This paper focuses on the results of experimental work on workability and compressive strength of self-compacting concrete （SCC）. The work concentrated on concrete mixes having water/binder ratios of 0.45 and 0.35, which contained constant total binder contents of 400 kg/m^3 and 500 kg/m^3, respectively. Based on the experimental results, the existing suggestions for anticipating the long-term compressive strength of SCC according to its compressive strength at the age of 7 days were not exact enough. Therefore, it is decided to use artificial neural networks （ANN） for predicting the long-term compressive strength of SCC from its workability and short-term compressive strength. For predicting the long-term compressive strength of SCC utilizing ANN, multi layer perceptron （MLP） networks and radial basis function （RBF） networks were chosen. The conclusion was that the MLP networks could properly predict the long-term compressive strength in all conditions, but RBF networks were not exact enough in some circumstances. On the other hand, RBF networks were more users friendly and they converged to the final networks quicker.
