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In order to reduce the dependency of resin synthesis on petroleum resources, vanillyl alcohol which is a renewable material that can be produced from lignin has been used to synthesize bioepoxy resin. Although it has been widely reported that the curing reaction and properties of the cured epoxies can be greatly affected by the molecular structure of the curing agents, the exact influence remains unknown for bioepoxies. In this study, four aliphatic amines with different molecular structures and amine functionalities, namely triethylenetetramine (TETA), Tris(2-aminoethyl)amine (TREN), diethylenetriamine (DETA), and ethylenediamine (EDA), were used to cure the synthesized vanillyl alcohol–based bioepoxy resin (VE). The curing reaction of VE and the physicochemical properties, especially the thermomechanical performance of the cured bioepoxies with different amine functionalities, were systematically investigated and compared using different characterization methods, such as DSC, ATR–FTIR, TGA, DMA, and tensile testing, etc. Despite a higher curing temperature needed in the VE–TETA resin system, the cured VE–TETA epoxy showed a better chemical resistance, particularly acidic resistance, as well as a lower swelling ratio than the others. The higher thermal decomposition temperature, storage modulus, and relaxation temperature of VE–TETA epoxy indicated its superior thermal stability and thermomechanical properties. Moreover, the tensile strength of VE cured by TETA was 1.4~2.6 times higher than those of other curing systems. In conclusion, TETA was shown to be the optimum epoxy curing agent for vanillyl alcohol–based bioepoxy resin.
Zhenyu Wang; Pitchaimari Gnanasekar; Sandeep Sudhakaran Nair; Songlin Yi; Ning Yan. Curing Behavior and Thermomechanical Performance of Bioepoxy Resin Synthesized from Vanillyl Alcohol: Effects of the Curing Agent. Polymers 2021, 13, 2891 .
AMA StyleZhenyu Wang, Pitchaimari Gnanasekar, Sandeep Sudhakaran Nair, Songlin Yi, Ning Yan. Curing Behavior and Thermomechanical Performance of Bioepoxy Resin Synthesized from Vanillyl Alcohol: Effects of the Curing Agent. Polymers. 2021; 13 (17):2891.
Chicago/Turabian StyleZhenyu Wang; Pitchaimari Gnanasekar; Sandeep Sudhakaran Nair; Songlin Yi; Ning Yan. 2021. "Curing Behavior and Thermomechanical Performance of Bioepoxy Resin Synthesized from Vanillyl Alcohol: Effects of the Curing Agent." Polymers 13, no. 17: 2891.
It is well-known that ultrasound has been studied for its cavitation, mechanical and thermal effects. As a pretreatment technology, ultrasonic alkali treatment has attracted much attention in the field of biomass biochemical transformation. In this study, the structural and dynamic changes of wood cell walls during ultrasound-water, alkali, and ultrasound-alkali treatments were investigated by stereoscopic microscopy, confocal Raman microscopy, Fourier-transform infrared spectroscopy, and X-ray diffraction. The results indicated that the ultrasound-water, alkali, and ultrasound-alkali treatments had the effect of removing extractives from conduits. The uniform self-shrinking samples with shrinkage conduits were obtained by the alkali and ultrasound-alkali treatments. All of the treatments affected the relative content, structure and distribution of the chemical components in the wood cell walls. Compared with water-immersion samples, the relative content of hemicellulose of the treated samples reduced from 32.31% to 7.02% for ultrasound-8% NaOH treated samples. For the signal intensity of lignin, ultrasound-water treated and ultrasound-alkali treated samples displayed a more significant reductions than the alkali treated samples in the cell wall region. The crystal zone and amorphous zone of cellulose coexisted before and after the treatment, for all of the treated samples, and particularly for the ultrasound-assisted treated samples, the crystallinity increased from 38.15% for water-immersion samples to 57.42% for ultrasound-8% NaOH treated samples.
Jing Qian; Fengbin Zhao; Jingjing Gao; Lijie Qu; Zhengbin He; Songlin Yi. Characterization of the structural and dynamic changes of cell wall obtained by ultrasound-water and ultrasound-alkali treatments. Ultrasonics Sonochemistry 2021, 77, 105672 .
AMA StyleJing Qian, Fengbin Zhao, Jingjing Gao, Lijie Qu, Zhengbin He, Songlin Yi. Characterization of the structural and dynamic changes of cell wall obtained by ultrasound-water and ultrasound-alkali treatments. Ultrasonics Sonochemistry. 2021; 77 ():105672.
Chicago/Turabian StyleJing Qian; Fengbin Zhao; Jingjing Gao; Lijie Qu; Zhengbin He; Songlin Yi. 2021. "Characterization of the structural and dynamic changes of cell wall obtained by ultrasound-water and ultrasound-alkali treatments." Ultrasonics Sonochemistry 77, no. : 105672.
This study elucidates the mechanism of the influence of ultrasonic treatment on wood pyrolysis and the details of the thermal stability changes of samples treated with ultrasonic alkali are explained. Four groups of samples were designed to clarify this scientific question, including the control group, the ultrasonic water-treated group, the alkali-treated group and the ultrasonic alkali-treated group. The extractives contents (organic extractives and hot water extractives) were determined, the crystal region, the functional groups of chemical components, the distribution of chemical components, and the thermal stability of wood were investigated using X-ray diffraction, Fourier-transform infrared spectroscopy, confocal Raman microscopy, and thermogravimetric analysis, respectively. The results suggested that all the treatments reduced the extractives contents, increased the relative crystallinity, destroyed the structure of hemicellulose and lignin, and affected the thermal stability of wood, to different degrees. Ultrasonic time and alkali concentration were shown to be two important indexes. Ultrasound can enhance the treatment effects of low concentration alkali (0.1 %), but in a highly concentrated alkali environment, the auxiliary effect is not obvious. Ultrasonic treatment reduced the intensity of lignin in the whole cell wall region, while alkali treatment followed a more systematic process as the solvent permeated from the S layer to CCML. The initial degradation temperature T0 was not only related to the extractives content but also to the concentrations of hemicellulose and lignin in the sample. The hemicellulose degradation temperature T1 and cellulose degradation temperature T2 changed with changes in T0. A detailed understanding of the spatial and temporal variations of the major components in the rigid cell wall during the pretreatment process will help to develop more effective pretreatment strategies, which is crucial for the efficient optimization of the process.
Jing Qian; Jingjing Gao; Fengbin Zhao; Luxi He; Tianfang Zhang; Zhengbin He; Songlin Yi. How does ultrasound influence the thermal stability of wood? Industrial Crops and Products 2021, 170, 113761 .
AMA StyleJing Qian, Jingjing Gao, Fengbin Zhao, Luxi He, Tianfang Zhang, Zhengbin He, Songlin Yi. How does ultrasound influence the thermal stability of wood? Industrial Crops and Products. 2021; 170 ():113761.
Chicago/Turabian StyleJing Qian; Jingjing Gao; Fengbin Zhao; Luxi He; Tianfang Zhang; Zhengbin He; Songlin Yi. 2021. "How does ultrasound influence the thermal stability of wood?" Industrial Crops and Products 170, no. : 113761.
Samples were pretreated by ultrasound at 300 W and 28 kHz in three different solutions. The thermal degradation characteristics of the samples were then characterized via thermogravimetric, differential scanning calorimetry, and Fourier transform infrared analysis in a nitrogen environment. The characteristic of gas product release, the formation mechanisms of the main products, and the mechanistic basis for the effects of ultrasound on wood components were studied. The results showed that the gaseous products are the same with ultrasound pretreatment but the amounts are changed. The gaseous products mainly constitute of CO, H2O, CO2, CH4, and CH3COOH, and more gaseous products were produced at 361 °C than at 308 °C. The reaction rates for specimens pretreated in aqueous soda solution proceeded faster than specimens pretreated in aqueous acetic acid solution and distilled water. Moreover, the maximum FTIR spectra absorbance appeared around 341 °C for specimens pretreated in aqueous soda solution but appeared around 369 °C for the control sample and samples pretreated in distilled water or acetic acid solution. The heat flows for specimens pretreated in aqueous soda solution, compared to control group, was much lower. Additionally, hydroxyl and hydroperoxy radicals provided by ultrasound cavitation in alkaline conditions act to intensify the overall rates of reactions.
Zhengbin He; Jing Qian; Zhenyu Wang; Songlin Yi; Jun Mu. Effects of Ultrasound Pretreatment on Eucalyptus Thermal Decomposition Characteristics As Determined by Thermogravimetric, Differential Scanning Calorimetry, and Fourier Transform Infrared Analysis. ACS Omega 2018, 3, 6611 -6616.
AMA StyleZhengbin He, Jing Qian, Zhenyu Wang, Songlin Yi, Jun Mu. Effects of Ultrasound Pretreatment on Eucalyptus Thermal Decomposition Characteristics As Determined by Thermogravimetric, Differential Scanning Calorimetry, and Fourier Transform Infrared Analysis. ACS Omega. 2018; 3 (6):6611-6616.
Chicago/Turabian StyleZhengbin He; Jing Qian; Zhenyu Wang; Songlin Yi; Jun Mu. 2018. "Effects of Ultrasound Pretreatment on Eucalyptus Thermal Decomposition Characteristics As Determined by Thermogravimetric, Differential Scanning Calorimetry, and Fourier Transform Infrared Analysis." ACS Omega 3, no. 6: 6611-6616.
In this study, the influence of ultrasound-assisted extraction on eucalyptus samples with special focus on pyrolysis characteristics and kinetic parameters was explored. Ultrasound and Soxhlet extraction were used to pretreat samples respectively, then samples were assayed by component analysis, TG-FTIR, and kinetic analysis. Ultrasound-assisted extraction did change the physiochemical characteristics of eucalyptus samples, particularly in regards to the quantity of extractives obtained. In TG and DTG curves, ultrasound-extracted samples reflected lower residual weight ratio (17.77%) and higher maximum weight loss rate (-22.92%/min), and were accompanied by a slight shift in the weight loss rate peak to lower temperature (366°C). The volatiles produced during pyrolysis and the discrepancies of product distribution between experimental and controlled groups were explored based on TG-FTIR spectra. According to kinetic analysis results, ultrasound-treated samples showed higher activation energy at the primary portion of thermal degradation with an average of 206.09kJ/mol.
Zhenyu Wang; Zhengbin He; Zijian Zhao; Songlin Yi; Jun Mu. Influence of ultrasound-assisted extraction on the pyrolysis characteristics and kinetic parameters of eucalyptus. Ultrasonics Sonochemistry 2017, 37, 47 -55.
AMA StyleZhenyu Wang, Zhengbin He, Zijian Zhao, Songlin Yi, Jun Mu. Influence of ultrasound-assisted extraction on the pyrolysis characteristics and kinetic parameters of eucalyptus. Ultrasonics Sonochemistry. 2017; 37 ():47-55.
Chicago/Turabian StyleZhenyu Wang; Zhengbin He; Zijian Zhao; Songlin Yi; Jun Mu. 2017. "Influence of ultrasound-assisted extraction on the pyrolysis characteristics and kinetic parameters of eucalyptus." Ultrasonics Sonochemistry 37, no. : 47-55.
To investigate the influence of moisture content (MC) and steaming temperature on defects developing during steaming prior to kiln drying, mass loss, heat transfer, microstructures, extractives, and chemical transformation of Eucalyptus grandis × E. urophylla specimens (with moisture content of 120, 70, 60, 50, 40, 30, 20%) were observed in this study. Specimens of each experimental moisture content were steamed at 80, 100, and 120 °C for 4 h after pre-heating at atmospheric pressure, respectively. Results revealed that it was most beneficial to conduct steaming at 100 °C when the moisture content was approximately 50% after air drying when stagewise heating-up and continuous steaming schedule were adopted. Under this condition, there was a notable decrease in defects including edge bends, surface splits, and inner splits. Steaming was also a drying period characterized by various extents of mass loss. Changes in microstructures and extractive contents proved the increasing permeability of steamed wood. Deacetylation and crosslinking reactions happened in the hemicellulose of the sample materials, which contributed to the loss of hemicellulose after treatment.
Lulu Kong; Zijian Zhao; Zhengbin He; Songlin Yi. Development of schedule to steaming prior to drying and its effects on Eucalyptus grandis × E. urophylla wood. European Journal of Wood and Wood Products 2017, 76, 591 -600.
AMA StyleLulu Kong, Zijian Zhao, Zhengbin He, Songlin Yi. Development of schedule to steaming prior to drying and its effects on Eucalyptus grandis × E. urophylla wood. European Journal of Wood and Wood Products. 2017; 76 (2):591-600.
Chicago/Turabian StyleLulu Kong; Zijian Zhao; Zhengbin He; Songlin Yi. 2017. "Development of schedule to steaming prior to drying and its effects on Eucalyptus grandis × E. urophylla wood." European Journal of Wood and Wood Products 76, no. 2: 591-600.
As an initial step to increase the use of renewable biomass resources, this study was aimed at investigating the effects of ultrasound pretreatment on structural changes of wood. Samples were pretreated by ultrasound with the power of 300W and frequency of 28kHz in aqueous soda solution, aqueous acetic acid, or distilled water, then pretreated and control samples were characterized via X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA). The results shown that ultrasound pretreatment is indeed effective in modifying the physiochemical structure of eucalyptus wood; the pretreatment decreased the quantity of alkali metals (e.g., potassium, calcium and magnesium) in the resulting material. Compared to the control group, the residual char content of samples pretreated in aqueous soda solution increased by 10.08%-20.12% and the reaction temperature decreased from 361°C to 341°C, however, in samples pretreated by ultrasound in acetic solution or distilled water, the residual char content decreased by 12.40%-21.45% and there were no significant differences in reactivity apart from a slightly higher maximum reaction rate. Ultrasound pretreatment increased the samples' crystallinity up to 35.5% and successfully removed cellulose, hemicellulose, and lignin from the samples; the pretreatment also increased the exposure of the sample to the treatment solutions, broke down sample pits, and generated collapses and microchannels on sample pits, and removed attachments in the samples.
Zhengbin He; Zhenyu Wang; Zijian Zhao; Songlin Yi; Jun Mu; Xiaoxu Wang. Influence of ultrasound pretreatment on wood physiochemical structure. Ultrasonics Sonochemistry 2017, 34, 136 -141.
AMA StyleZhengbin He, Zhenyu Wang, Zijian Zhao, Songlin Yi, Jun Mu, Xiaoxu Wang. Influence of ultrasound pretreatment on wood physiochemical structure. Ultrasonics Sonochemistry. 2017; 34 ():136-141.
Chicago/Turabian StyleZhengbin He; Zhenyu Wang; Zijian Zhao; Songlin Yi; Jun Mu; Xiaoxu Wang. 2017. "Influence of ultrasound pretreatment on wood physiochemical structure." Ultrasonics Sonochemistry 34, no. : 136-141.
Superheated steam vacuum drying shows major advantages in terms of reducing the boiling point of water and speeding up the drying process, but to our knowledge, no researcher has addressed the effects of drying conditions on heat transfer characteristics during superheated steam vacuum drying of wood. In this study, we did so using fast-growing poplar. Temperatures inside the wood were measured and the convective heat transfer coefficients calculated under temperature conditions of 35°C, 55°C, and 70°C and absolute pressures of 0.03, 0.06, and 0.1 MPa. The results of our subsequent analysis showed that the ultimate temperatures inside wood increase alongside increasing absolute pressure at the set temperature conditions and are lower than that of the drying medium. In addition, we found that convective heat transfer coefficients increase as absolute pressure increases at the set temperatures and also increase as temperature increases at set absolute pressure conditions. We then established a convective heat transfer coefficient model based on the experimental results. The findings presented here may provide theoretical guidance for maximizing the available advantages of superheated steam vacuum drying and choosing appropriate drying schedules for poplar in future applications.
Zhengbin He; Shu Qiu; Yu Zhang; Zijian Zhao; Songlin Yi. Heat Transfer Characteristics during Superheated Steam Vacuum Drying of Poplar. Forest Products Journal 2016, 66, 308 -312.
AMA StyleZhengbin He, Shu Qiu, Yu Zhang, Zijian Zhao, Songlin Yi. Heat Transfer Characteristics during Superheated Steam Vacuum Drying of Poplar. Forest Products Journal. 2016; 66 (5-6):308-312.
Chicago/Turabian StyleZhengbin He; Shu Qiu; Yu Zhang; Zijian Zhao; Songlin Yi. 2016. "Heat Transfer Characteristics during Superheated Steam Vacuum Drying of Poplar." Forest Products Journal 66, no. 5-6: 308-312.
Large quantities of volatile organic compounds (VOCs) are released from heat-treated bamboo during the manufacturing process of recombinant bamboo, which affects the environment and human health. In this study, bamboo was treated at 150 °C, 180 °C, and 210 °C for 3 h, and VOCs were collected every hour using a Tenax tube. The VOCs were analyzed with gas chromatography-mass spectrometry (GC-MS) to explore the effect of temperature and time on weight loss ratio, main components, and their relative proportions. The results showed that temperature considerably influenced weight loss ratio, and weight loss ratio increased rapidly at high temperature. Massive quantities of VOC were emitted during the first hour of treatment, and emissions decreased as the time and temperature increased. Terpenes were the primary component of the VOC emissions. Temperature and time exhibited minimal effects on the type of primary components, and the relative proportion of some components exhibited negligible changes over a range of temperatures and times.
Wenjuan Huang; Yafeng Wu; Zijian Zhao; Songlin Yi; Zhengbin He. Influence of Thermal Treatment Conditions on the Release of Volatile Organic Compounds from Bamboo. BioResources 2016, 11, 1 .
AMA StyleWenjuan Huang, Yafeng Wu, Zijian Zhao, Songlin Yi, Zhengbin He. Influence of Thermal Treatment Conditions on the Release of Volatile Organic Compounds from Bamboo. BioResources. 2016; 11 (3):1.
Chicago/Turabian StyleWenjuan Huang; Yafeng Wu; Zijian Zhao; Songlin Yi; Zhengbin He. 2016. "Influence of Thermal Treatment Conditions on the Release of Volatile Organic Compounds from Bamboo." BioResources 11, no. 3: 1.
Impregnating wood, assisted with ultrasound technology, could improve the impregnation efficiency by improving the permeability of wood, thus affecting the subsequent drying process. Poplar lumber and phenolic resin were applied to investigate the influence of ultrasound-assisted impregnation on the wood drying process. The ultrasonic frequency and processing time were analyzed and correlated. The results indicated that the average drying rate of impregnated wood was generally faster in the earlier stage and slower in the later period than the blank group. At the earlier drying stage, the drying rate exhibited a decreasing tendency with increasing ultrasonic time, as the frequency remained constant. However, with an unaltered processing time, a contrary trend was detected as the frequency was increased. The ultrasonic frequency and time caused an complex effect on the average drying rate during the later drying course. These findings could be applied to the impregnated wood drying industry to strike a balance between ultrasound-assisted performance and the related drying effectiveness.
Zijian Zhao; Qing Ma; Zhengbin He; Songlin Yi. Effects of Frequency and Processing Time on the Drying Course of Ultrasound-assisted Impregnated Wood. BioResources 2015, 11, 1 .
AMA StyleZijian Zhao, Qing Ma, Zhengbin He, Songlin Yi. Effects of Frequency and Processing Time on the Drying Course of Ultrasound-assisted Impregnated Wood. BioResources. 2015; 11 (1):1.
Chicago/Turabian StyleZijian Zhao; Qing Ma; Zhengbin He; Songlin Yi. 2015. "Effects of Frequency and Processing Time on the Drying Course of Ultrasound-assisted Impregnated Wood." BioResources 11, no. 1: 1.
To modify the acoustic properties of dawn redwood (Metasequoia glyptostroboides Hu et Cheng), thermal, ultrasonic, and combined thermal-ultrasound treatments were employed in this work. The changes in the logarithmic decrement (δ), specific Young’s modulus (E’/ρ), and extractives content were examined. The results showed that thermal and ultrasonic treatments were both essential for a decrease in the logarithmic decrement (δ) and an increase in the specific Young’s modulus (E’/ρ) of dawn redwood (Metasequoia glyptostroboides Hu et Cheng). A superposition effect on decreasing of the logarithmic decrement (δ) was discovered after thermal-ultrasound combined treatment. The amounts of extractives, extracted by 95 °C distilled water, 1% NaOH solution, and benzene-ethanol solution, decreased after thermal and ultrasonic treatments. Moreover, there was a linear correlation between logarithmic decrement (δ) and extractives, in which extractives from 1% NaOH solution and 95 °C distilled water had a significant effect. Finally, dawn redwood samples treated with ultrasonic power at 340 W for 9 min at a thermal temperature of 200 °C were chosen as the optimal method in this research.
Yafeng Wu; Tingou Sha; Zijian Zhao; Zhengbin He; Songlin Yi. Influence of Different Pretreatments on the Acoustic Properties of Dawn Redwood (Metasequoia glyptostroboides Hu et Cheng). BioResources 2015, 11, 1 .
AMA StyleYafeng Wu, Tingou Sha, Zijian Zhao, Zhengbin He, Songlin Yi. Influence of Different Pretreatments on the Acoustic Properties of Dawn Redwood (Metasequoia glyptostroboides Hu et Cheng). BioResources. 2015; 11 (1):1.
Chicago/Turabian StyleYafeng Wu; Tingou Sha; Zijian Zhao; Zhengbin He; Songlin Yi. 2015. "Influence of Different Pretreatments on the Acoustic Properties of Dawn Redwood (Metasequoia glyptostroboides Hu et Cheng)." BioResources 11, no. 1: 1.
Zhengbin He; Yu Zhang; Zhenyu Wang; Zijian Zhao; Songlin Yi. Reducing wood drying time by application of ultrasound pretreatment. Drying Technology 2015, 34, 1141 -1146.
AMA StyleZhengbin He, Yu Zhang, Zhenyu Wang, Zijian Zhao, Songlin Yi. Reducing wood drying time by application of ultrasound pretreatment. Drying Technology. 2015; 34 (10):1141-1146.
Chicago/Turabian StyleZhengbin He; Yu Zhang; Zhenyu Wang; Zijian Zhao; Songlin Yi. 2015. "Reducing wood drying time by application of ultrasound pretreatment." Drying Technology 34, no. 10: 1141-1146.
Ultrasound was applied to enhance mass transfer within the boundary layer during wood vacuum drying. Fast growing poplar (Populus tomentosa) was used as the specimen in this work. The water migration rates and the mass transfer coefficients were studied at temperatures of 35 and 50 °C, absolute pressures of 0.03, 0.06, and 0.1 MPa, and ultrasound power-frequency groups of 60 W-28 kHz, 100 W-28 kHz, and 100 W-20 kHz, respectively. The results indicated that ultrasound could markedly increase the water migration rates within the boundary layer. The water migration rates increased with increasing ultrasound power and frequency. The mass transfer coefficients within the boundary layer for specimens treated with ultrasound were much higher than those of the control group, and the mass transfer coefficients increased with decreasing absolute pressure. Ultrasound could be applied in the wood drying industry as a means of saving time and energy.
Zhengbin He; Zhenyu Wang; Huan Lv; Zhenyu Zhang; Songlin Yi. Effects of Ultrasound on Mass Transfer within the Boundary Layer during Wood Vacuum Drying. BioResources 2015, 10, 1 .
AMA StyleZhengbin He, Zhenyu Wang, Huan Lv, Zhenyu Zhang, Songlin Yi. Effects of Ultrasound on Mass Transfer within the Boundary Layer during Wood Vacuum Drying. BioResources. 2015; 10 (3):1.
Chicago/Turabian StyleZhengbin He; Zhenyu Wang; Huan Lv; Zhenyu Zhang; Songlin Yi. 2015. "Effects of Ultrasound on Mass Transfer within the Boundary Layer during Wood Vacuum Drying." BioResources 10, no. 3: 1.
Zhengbin He; Zijian Zhao; Fei Yang; Songlin Yi. Effect of ultrasound pretreatment on wood prior to vacuum drying. Maderas. Ciencia y tecnología 2014, 16, 395 -402.
AMA StyleZhengbin He, Zijian Zhao, Fei Yang, Songlin Yi. Effect of ultrasound pretreatment on wood prior to vacuum drying. Maderas. Ciencia y tecnología. 2014; 16 (4):395-402.
Chicago/Turabian StyleZhengbin He; Zijian Zhao; Fei Yang; Songlin Yi. 2014. "Effect of ultrasound pretreatment on wood prior to vacuum drying." Maderas. Ciencia y tecnología 16, no. 4: 395-402.
Ultrasound pretreatment of wood prior to drying was examined as a method to increase the effective water diffusivity, reduce drying time, and improve product quality of Chinese Catalpa wood. Pretreatment tests were carried out at three pretreatment durations, three absolute pressure levels, and three ultrasonic intensities. All specimens were then dried at 60°C and the absolute pressure level of 0.02 MPa to determine the effects of pretreatment parameters on vacuum drying characteristics. A microscopic analysis was carried out to visualize the formation of microchannels and view any other changes to wood tissue structure that occurred. Results showed that ultrasound pretreatment prior to vacuum drying enhances the effective water diffusivity; the higher the ultrasound power level, the longer the pretreatment time, and the lower the absolute pressure, the shorter is the drying time. Ultrasound creates micro channels within the tissue of wood during pretreatment. However, the pretreatment time should not be too long when the ultrasound is high.
Zhengbin He; Fei Yang; Songlin Yi; Jianmin Gao. Effect of Ultrasound Pretreatment on Vacuum Drying of Chinese Catalpa Wood. Drying Technology 2012, 30, 1750 -1755.
AMA StyleZhengbin He, Fei Yang, Songlin Yi, Jianmin Gao. Effect of Ultrasound Pretreatment on Vacuum Drying of Chinese Catalpa Wood. Drying Technology. 2012; 30 (15):1750-1755.
Chicago/Turabian StyleZhengbin He; Fei Yang; Songlin Yi; Jianmin Gao. 2012. "Effect of Ultrasound Pretreatment on Vacuum Drying of Chinese Catalpa Wood." Drying Technology 30, no. 15: 1750-1755.
Ultrasonic energy was applied to assist the wood vacuum drying process. At a drying temperature of 60°C, the absolute pressure was either 0.05 MPa or 0.08 MPa; the ultrasonic power and frequency were 100 W and 28 kHz, respectively. The results showed that the effective water diffusivity of the specimens dried by the ultrasonic assisted vacuum drying at 0.05 MPa or 0.08 MPa were higher than that of the samples dried without ultrasound. The ultrasound-vacuum drying rate was much faster than that of drying without ultrasound, especially for wood with a moisture content above the fiber saturation point. Drying at the absolute pressure of 0.05 MPa was faster than that of 0.08 MPa. Ultrasound-assisted drying was especially more beneficial when removing free water. The ultrasound-vacuum drying method could be applied in the wood drying industry as a means of saving energy and minimizing product quality damage.
Zhengbin He; Yang Fei; Yiqing Peng; Songlin Yi. Ultrasound-Assisted Vacuum Drying of Wood: Effects on Drying Time and Product Quality. BioResources 2012, 8, 855-863 .
AMA StyleZhengbin He, Yang Fei, Yiqing Peng, Songlin Yi. Ultrasound-Assisted Vacuum Drying of Wood: Effects on Drying Time and Product Quality. BioResources. 2012; 8 (1):855-863.
Chicago/Turabian StyleZhengbin He; Yang Fei; Yiqing Peng; Songlin Yi. 2012. "Ultrasound-Assisted Vacuum Drying of Wood: Effects on Drying Time and Product Quality." BioResources 8, no. 1: 855-863.