Papers by Keyword: Poplar

Abstract: This study, by means of GC-MS and HPLC, investigated the characteristics of volatile organic compounds (VOCs) released from fiber hot-pressing in a medium density fiberboard (MDF) production line with a production capacity of 80,000 m3/a. The quantity of total volatile organic compounds (TVOC), aldehydes and ketones were calculated. The results showed that the concentration of TVOC reached 1.8940 mg/m3. The main components include terpenes, acrolein and acetone, benzenes series and saturated hydrocarbons. The concentration of the mixture of aldehydes and ketones was 5.1136 mg/m3.

Abstract: In order to stimulate growth model of poplar and achieve the visualization of poplar growth, the growth model is investigated from the perspective of computer simulation technology. The paper first presents physiological changes of poplar, discusses the changing rules of the space-time state of poplar growth, proposes the growth model of poplar based on state machine and predicts the growth of poplar authentically. Based on this model, the visualization algorithm of poplar growth is constructed; the data of poplar growth is properly organized; a simulation prototype system is developed to verify the validity of the model. Practice has shown that this growth model can simulate growth process of poplar and has high correctness and efficiency in the application of poplar visualization.

Abstract: Xylanase is effective and specificity to xylose catalytic degradation, and has strong adaptability. In this paper, effect of xylanase treatment on the drainge and physical properties of high yield pulp was studied. The results showed that, compared with the untreated high yield pulp .The brightness of the treated pulp increased 1.84 %ISO, light scattering coefficient alse increased, opacity coefficient decreased. Tearing index, breaking length and bursting index respectively increased by 15.7%,9.07% and 14.85%.

Abstract: Many studies have successfully applied near infrared (NIR) spectroscopy to estimate important wood properties. In this paper, the use of NIR (350–2500 nm) spectroscopy to predict the cellulose crystallinity of Poplar (Populus nigra var.) was investigated. The calibration and test models were constructed using partial least squares regression (PLS). The correlations were significant both the calibration and the test samples using six factors, and the correlation coefficients (R2) were 0.9367, 0.9472 respectively. The results suggest that NIR spectroscope may provide a useful tool for rapid and accurate prediction of the cellulose crystallinity of Poplar.

Abstract: Through impregnating with UF resin, the modification technology of Poplar was experimented and studied. The study results proved that the laminated veneer lumber (LVL), impregnated with UF resin, reached fine quality when the bumping vacuum time, the solid content of UF resin, the impregnation temperature and time were respectively 40min, 30%, 25-30°C and 3 hours. The picture of electron microscope showed that in LVL impregnated with UF resin, the wood vessels and cells near the veneer junction sections occurred mostly deformation, but the wood cells depart farther from the veneer junction sections occurred rarely deformation. The cell lumens and middle lamella near the veneer junction sections were almost filled by the resin，but the scarcely any resin filled in the wood cell lumens depart farther from the veneer junction sections.

Abstract: This study, by means of GC-MS and HPLC, investiagted the characteristics of volatile organic compounds (VOCs) released from fiber dryer in a high density fiberboard (HDF) production line with a production capacity of 100,000 m³/a. The quantity of total volatile organic compounds (TVOC), aldehydes and ketones were calculated. The results showed that the concentration of VOCs reached 0.5275 mg/m³. The main components include benzenes series (42.7%), terpenes (11.0% alpha pinene), alkanes (11.2%), anhydrides (4.7%) and aldehydes (3.1%). The concentration of the mixture of aldehydes and ketones was 8.8594 mg/m³. The annual emission of TVOC and the mixture of aldehydes and ketones from HDF fiber dryer were 836 kg/a and 14033 kg/a, respectively.

Abstract: The poplar is important part of shelterbelt trees, so the farmland shelterbelts based on poplar play an important part in the plain, in recent years the research on structure and efficiency mode of farmland shelterbelt are more, while the prediction models of the yield and quality of the polar are much less. The growth model is main material base of poplar growth, the development of information technology provides new methods for the quantitative study of poplar growth model and evaluation. The information technology is used to extract growth character parameters of poplar, and the neural networks is used to establish the relational model of the character parameters and wood materials and wood production of poplar, these models are used to monitor and analyze growth situation and materials of poplar and potential utilization value, so can correctly assess the reasonable use of the poplar, meanwhile provide the basis for the oriented cultivation of poplar management, which have important theory value and practical significance.

Abstract: The aims of prehydrolysis are mainly removing pentose and decreasing viscosity in the preparation process of dissolving pulp. In this paper, the effect of prehydrolysis in the preparation process of poplar and bamboo dissolving pulp were investigated under different prehydrolysis conditions. The optimum prehydrolysis process conditions of poplar were obtained as followings: the liquid ratio of 1:6, the highest temperature of 160±2°C, heating time of 90min, holding time of 120min, H₂SO₄ of 1.0%, the P-factor was 1537. Under this condition, the results showed that the content of pentosan decreased from 24.10% to 7.85%. The optimum prehydrolysis process conditions of bamboo were obtained as followings: the liquid ratio of 1:8, the highest temperature of 160±2°C, heating time of 90min, holding time of 120min, H₂SO₄ of 1.0%, the P-factor was 1549.And the content of pentosan was also decreased from 19.64% to 6.76% by the prehydrolysis process.

Abstract: Paper properties, including physical properties and optical properties, fiber quality analysis and COD in the pulp effluent were used to investigate the effects of substituting Mg (OH)₂ for NaOH on the properties of poplar APMP in this paper. The results from fiber quality analysis showed that increasing the substitution levels of Mg (OH)₂ for NaOH in the poplar APMP could increase the content of fiber fines,the pulp had shorter average length,and levels of kinking and curl reduced.The results of paper properties analysis ,including physical properties and optical properties ,showed that the bulk and light scattering coefficient of handsheets could be improved,while the physical strength and brightness couled be decreased after using Mg (OH)₂.The research for COD in the pulp effluent showed that it could reduce content of COD in the pulp effluent after substituting Mg (OH)₂ for NaOH on the properties of poplar APMP,so that clean production can come true easierly,while it could retrench the cost of production and yield good economic returns.

Abstract: The testing experiments to healthy poplar and larch logs samplings were conducted by using hydraulic machine. The relationships among compression and bending strength, modulus of elasticity in compression and bending were studied in the two logs samplings. The results indicated that, in the both species, the compression strength had certain linear correlation with bending strength, and so did the modulus of elasticity in compression and bending. Meanwhile there were remarkable linear correlations with the compression strength and the modulus of elasticity in compression as well as the bending strength and the modulus of elasticity in bending.