Guobing Xiong¹, Lu Hong², Zehui Ju³, Xiaoning Lu^3,*, Juwan Jin^3,*

Journal of Renewable Materials, Vol.11, No.9, pp. 3447-3461, 2023, DOI:10.32604/jrm.2023.027430

Abstract The study characterized the curing behaviors of phenol formaldehyde (PF) resin under different vacuum degrees and explored the properties of 9-ply plywood panels hot-pressed under both vacuum and atmospheric conditions. The changes in core temperature and moisture content of the plywood mats during hot pressing were investigated as well. It was found that the gel times and gel temperatures of PF resin decreased with the increase of vacuum degree using a self-made device. FTIR spectra indicated the degree of polycondensation of hydroxymethyl gradually increased with the increase in temperature. It was also observed that a higher degree of vacuum led… More >

Wenwei Li¹, Xinjie Zhan^2,*, Baotian Wang¹, Jinyu Zuo¹

Journal of Renewable Materials, Vol.11, No.1, pp. 363-378, 2023, DOI:10.32604/jrm.2022.022254

Abstract Municipal sludge is a sedimentation waste produced during the wastewater process in sewage treatment plants. Among recent studies, pilot and field tests showed that chemical conditioning combined with vacuum preloading can effectively treat municipal sludge. To further understand the drainage and consolidation characteristics of the conditioning sludge during vacuum preloading, a large deformation nonlinear numerical simulation model based on the equal strain condition was developed to simulate and analyze the pilot and field tests, whereas the simulation results were not satisfactory. The results of the numerical analysis of the pilot test showed that the predicted consolidation degree was greater than… More >

Pengfei Guan¹, Ping Li², Yiqiang Wu¹, Xingong Li¹, Guangming Yuan¹, Yingfeng Zuo^1,*

Journal of Renewable Materials, Vol.10, No.9, pp. 2451-2463, 2022, DOI:10.32604/jrm.2022.020459

Abstract To enhance mechanical properties and improve flame retardancy and smoke suppression of fast-growing poplar wood in wood applications, the wood was impregnated and modified. An organic phenolic prepolymer and inorganic sodium silicate was used as contrasting impregnation modifiers and wood samples were impregnated by a bionic “respiration” method with alternating positive and negative pressure. The weight percentage gain, density increase ratio, mechanical properties (bending and compressive strength and hardness), and water absorption rate of inorganic and organic-impregnated modified poplar wood (IIMPW and OIMPW, respectively) were compared and these properties in IIMPW were found to be higher than those of OIMPW… More >

Lu Hong¹, Biqing Shu^1,2, Qian He¹, Zehui Ju¹, Haiyang Zhang¹, Xiaoning Lu^1,*

Journal of Renewable Materials, Vol.9, No.1, pp. 49-59, 2021, DOI:10.32604/jrm.2021.013833

Abstract Chinese fir was compressed by vacuum hot pressing and conventional hot pressing at different temperatures (180°C, 200°C and 220°C), respectively. The color parameters of the heat-compressed sample were measured, the relative mechanical properties of the material were tested and changes in the chemistry of fir were investigated using Fourier transform infrared spectroscopy (FTIR) and Xray photoelectron spectroscopy (XPS). The results indicated that the color difference between compressed and untreated wood increased gradually with the increase of temperature. Compared with the conventional hot pressing treatment, the color difference (ΔE*) of the Chinese fir treated by vacuum hot pressing decreased by 43.73%,… More >

A.B. Mahmud Hasan^1,2, M A Wahab¹, S.M. Guo¹

Structural Durability & Health Monitoring, Vol.4, No.4, pp. 231-240, 2008, DOI:10.3970/sdhm.2008.004.231

Abstract This paper presents details analysis of Heat Affected Zone (HAZ) in High Temperature Vacuum Tube Furnace (HTVTF) to predict fracture region in tube wall due to thermal stress from temperature variation across its thickness. A simple mathematical model is used to illustrate stress concentration arising due to thermal stresses in tube wall and HAZs. Finite element model and analysis were carried out utilizing finite element analysis commercial codes. Combination of thermal stress due to temperature difference determine fracture region. Experimental and simulation results of inside temperature of tube are observed and similar relation have been found. Observation of heat affected… More >

Tao Yang, Zhaohui Meng, Hailong Ge, Xiangchen Fang*

The International Conference on Computational & Experimental Engineering and Sciences, Vol.22, No.2, pp. 140-140, 2019, DOI:10.32604/icces.2019.04917

Abstract Vacuum residue (VR) is the heaviest distillation cuts of crude oil. Being very intractable, VR contains high amount of sulfur, metal and asphaltene. Conventional VR conversion technologies, including delayed coker and residue fluidized catalytic cracking, cannot remove those impurities efficiently, or have to employ strict pretreatments for feed stock to meet the equipment and catalyst requirements. Hydroprocessing and hydrocracking process can convert VR into lighter oils, and remove sulfur and metal content at high efficiency; the refining nature of hydrogenation reactions could also improve the molecular structures of product cuts, increasing the commercial values. According to the fluidization state of… More >

Haojun Peng^1,*, Ping Zhang²

CMES-Computer Modeling in Engineering & Sciences, Vol.114, No.1, pp. 59-73, 2018, DOI:10.3970/cmes.2018.114.059

Abstract In this paper, a three dimension model is built according to real surface cleaner in airport runway rubber mark cleaning vehicle and numerical simulation of this model is carried out using Ansys Fluent software. After comparison and analysis the flow field between high speed rotating waterjet and static waterjet formerly studied by other researchers, the influences of different standoff distance from nozzle outlet to runway surface and rotation speed on rubber mark cleaning effect is simulated and analyzed. Results show the optimal operation parameters for the simulated model and quantitative advices are given for design, manufacture and operation of the… More >

K. Kakuda¹, Y. Ushiyama¹, S. Obara¹, J. Toyotani¹, S. Matsuda², H.Tanaka², K. Katagiri²

CMES-Computer Modeling in Engineering & Sciences, Vol.66, No.3, pp. 215-226, 2010, DOI:10.3970/cmes.2010.066.215

Abstract The application of the MPS (Moving Particle Semi-implicit) scheme to incompressible viscous fluid flow problem in the liquid ring vacuum pump with rotating impeller is presented. The rotating impeller in the pump is attached to a center hub and located in off-set from the center of a cylindrical body. For such flow problem there are some interesting phenomena including the formation of the liquid ring by rotating impeller, the interface dynamics between gas and liquid, and so forth. The MPS scheme is widely utilized as a particle strategy for the free surface flow, the problem of moving boundary, and multi-physics/multi-scale… More >

Yuan Chen¹, Honggang Duan¹, Fei Yu¹, Xingyu Zhao¹, Han Xu¹, Jun Gao^1,2

FDMP-Fluid Dynamics & Materials Processing, Vol.11, No.2, pp. 127-142, 2015, DOI:10.3970/fdmp.2015.011.127

Abstract The dynamics of dispersed bubbles in a centrifugal separator are investigated with the aim to improve the efficiency of the system. The prototype separator consists of a rotor, a base, a diverting disc, a shaft, an oil trapping impeller, a central pipe, an inlet section for contaminated oil, an outlet section for purified oil and an air outlet. A hydrodynamic model is developed to predict the complex influence of parameters such as the centrifugal force and vacuum pressure. In particular, three different force models are selected to analyze the effect of the added mass and Basset forces (also including inertia,… More >