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Zhao W.,Beijing University of Chemical Technology | Wang Y.,Beijing University of Chemical Technology | Wang Y.,Kailuan Group Ltd Liability Corporation | Wang X.,Beijing University of Chemical Technology | Wu D.,Beijing University of Chemical Technology
Ceramics International | Year: 2015

A type of new fiber-reinforced geopolymeric composites was developed by combining metakaolin and polyacetal (POM) fibers. High-strength POM fibers were first prepared through melt spinning followed by a hot-drawing procedure, and then a series of metakaolin-based geopolymeric composites with different contents of POM fibers were synthesized. The mechanical and tribological properties of the resulting composites were evaluated, and the morphology and microstructure were investigated. The POM fibers provided significant mechanical reinforcement for the metakaolin-based geopolymer. The composites were optimized for flexural and compressive strength with respect to fiber content and fiber length. Compared to unreinforced geopolymer, the composites obtained an optimum improvement by approximate 150% in flexural strength and by almost 26% in compressive strength. Moreover, the longer POM fibers exhibit a better reinforcement effect on the geopolymer, resulting in a lower optimal fiber content for the composites to achieve the maximum mechanical data. The reinforcing mechanisms were discussed on the basis of morphological investigation and considered as a cumulative energy-dissipating effect by fiber pullout and orientation, fiber rupture, fiber debonding from the matrix, and fiber bridging within cracks. The geopolymeric composites also achieved a considerable reduction in friction coefficient and abrasion loss rate in the presence of POM fibers. Such an enhancement of tribological performance is ascribed to the formation of self-lubricating transfer films between the contact surfaces of composites against the steel counterpart. © 2016 Elsevier Ltd and Techna Group S.r.l.

Bao Y.,Handan College | Gao R.,Handan College | Guo D.,Handan College | Bai S.,Handan College | Xin X.,Kailuan Group Ltd Liability Company
Chemical Engineering Transactions | Year: 2015

Ground penetrating radar is a high-resolution engineering geophysical method which has better detection effect to disengaging, cavities and leakiness in urban road base. This paper is based on the principle of ray tracing through the forward modelling of urban road base hollow, empty and not dense disease, analyses waveform, frequency, wave propagation characteristics of primary disease forward image simulation. The paper summarizes the urban road base diseases in ground penetrating radar profile feature of signal, and analyses field exploration radar profile and further research on primary diseases of urban road ground penetrating radar fingerprint for urban road base disease detection of ground penetrating radar data interpretation to provide the reference. Copyright © 2015, AIDIC Servizi S.r.l.

Wang Y.,Hebei Polytechnic University | Qin Y.,China University of Mining and Technology | Zhang J.,Hebei Polytechnic University | Zhang J.,Kai Luan group Ltd Liability Company
ICMHPC - 2010 International Conference on Mine Hazards Prevention and Control | Year: 2010

The coupling mathematical model is established including velocity field, oxygen concentration field and temperature field in goaf according to the theory of Finite Volume Method (FVM) and the flowing field safety theory to reveal the characteristics of spontaneous combustion. What's more, the moving coordinates is introduced based on the character of the moving workface, so the visual graphic program is also developed to calculate and simulate the velocity field, the oxygen concentration distribution in goaf by VB program and tecplot software. The simulation result is satisfied with the fact of goaf. At the same time, the program can describe distinctly the dynamic change situation and the influence of various conditions on spontaneous combustion in goaf. And the result can provide the detailed data information and the theoretical basis for preventing from spontaneous combustion in goaf. © Atlantis Press, 2010.

Wang Y.,Beijing University of Chemical Technology | Wang Y.,Kailuan Group Ltd Liability Corporation | Zhao W.,Beijing University of Chemical Technology | Wang X.,Beijing University of Chemical Technology | Wu D.,Beijing University of Chemical Technology
Fibers and Polymers | Year: 2016

The polyoxymethylene (POM) fiber was melt spun by use of different commercial grades of POM resin, and the effect of post-drawing on mechanical properties and microstructures was investigated extensively. The fiber obtained from the POM resin with a higher melt flow index (MFI) exhibits a better hot-drawing capability and also achieves a greater ultimate draw ratio. The mechanical evaluation reveals that the tensile strength and elastic modulus of POM fiber are improved significantly after post-drawing compared to the as-spun fibers. Although the greater draw ratios result in higher mechanical strength and modulus for the POM fiber, the fiber obtained from the POM resin with an MFI of 13.0 g/10 min achieves the optimal mechanical performance at the ultimate draw ratio. The morphologic and structural developments of POM fiber were studied by scanning electronic microscopy and X-ray powder diffraction. The results indicate that the POM fiber spun by the resin with an MFI of 13.0 g/10 min has a smooth lateral surface and a compact cross section after post-drawing. The fiber samples spun by the POM resins with low MFIs show some hollow disfigurements as well as a rough surface at the ultimate draw ratio, whereas the fiber obtained from the resin with a high MFI of 27.0 g/10 min presents the ununiformity of diameter after post-drawing. The POM fibers achieve a crystalline orientation during the hot-drawing process, which results in a transformation from the spherulitic crystals to the lamellar structure in the drawing direction. The level of crystalline orientation can be improved with an increase of draw ratio and thus results in a high modulus and strength for the resulting POM fiber samples. In addition, the thermal analysis indicates that the crystallinity of the as-spun fibers can be enhanced by post-drawing due to the orientation-induced crystallization. © 2016, The Korean Fiber Society and Springer Science+Business Media Dordrecht.

Wang Y.,Beijing University of Chemical Technology | Wang Y.,Kailuan Group Ltd Liability Corporation | Wang X.,Beijing University of Chemical Technology | Wu D.,Beijing University of Chemical Technology
Composite Interfaces | Year: 2016

The polyoxymethylene (POM)/basalt fiber composites were prepared by use of long fiber-reinforced thermoplastic technology through melt pultrusion. The mechanical and tribological properties, morphology, and thermal stability of the resulting composites were investigated. The composites exhibit significant improvements in tensile, flexural, and notched impact strength. These mechanical strength and toughness are dependent on the fiber content over the full range of the study. The residual fiber length and distribution in the injection-molded specimens were characterized. The prominent reinforcement effect of basalt fiber on POM is derived from the supercritical fiber length, which is much longer than that of the short fiber-reinforced ones and thus makes the composites take full advantage of the strength of the reinforcing fibers. The Kelly–Tyson model was used to predict the ultimate tensile strength of POM composites using the measured values of residual fiber length in the matrix, but the deviations were observed at the high contents of basalt fiber. The morphologic investigation indicates that the fiber pullout and fiber breakage both contribute energy dissipation to the tensile fracture of the composites. The tribological characterization indicates that the friction coefficients and specific wear rates of POM composites also decrease remarkably. Such an improvement of tribological performance is due to the presence of the high wear-resistant basalt fibers on the top of the worn surface bearing the dynamic loadings under sliding. Moreover, the dynamic mechanical analysis reveals that the storage moduli of the composites increase with increasing the fiber content, whereas the loss factors present an opposite trend. © 2016 Informa UK Limited, trading as Taylor & Francis Group

Zhang J.,China University of Mining and Technology | Zhang J.,KaiLuan group Ltd Liability Company | Zhou X.,China University of Mining and Technology | Gong W.,China University of Mining and Technology | Wang Y.,Hebei Polytechnic University
Communications in Computer and Information Science | Year: 2010

To provide a theoretical basis for application of inert gas injection measures on the mine fire disaster relief, the paper establish mathematical model for the influence of inert gas injection to fire zone's flow field, and the FLUENT software is used to carry out numerical simulation, at last, the simulation results are compared with the experimental results. The result shows that, while the velocity of inert gas is in low, the gas layer of closed fire zone is still existing; its verified the effect that inert gas can promote the front gas layer and dilution the back mixed gas layer; what's more, the numerical simulation of experiments verify the reliability of the results inert gas injection. The results have great significance on mastering the fire zone's state change when injecting the inert gas, forecasting the explosion suppression effects and giving a good guide on using the inert gas to suppress the fire zone's explosion. © Springer-Verlag 2010.

Wang Y.,Hebei Polytechnic University | Qin Y.,China University of Mining and Technology | Zhang J.,KaiLuan Group Ltd Liability Company
Communications in Computer and Information Science | Year: 2010

The new arithmetic of Finite Volume Method (FVM) is created according to the conservation principle in evey control volume, which has great effect on the calculation accuracy of equation. In order to prove the method, the temperature field of transient heat transfer is taken as example in paper to deduced equation, and the result shows that it is same to the result of FEM which is created by variational principle with high precision, except the coefficient of time change. So the new arithmetic of FVM explains successfully the actual physical meaning of triangular element in the variation formula, and can simplify the modeling process while improving the accuracy of finite volume method. In addition, the actual problem of three-dimensional temperature field of thermal calculations is resolved by the new arithmetic of FVM and the FEM, comparing FVM results with the theoretical solution, FEM result shows that the FVM is more similar with the theory than the FEM. As a word, the he new arithmetic of FVM not only can simply the process of establish equation but also can make sure of the calculation accuracy. What's more, it can extend widely the applied range of the FEM on the problem of temperature field, and has great application value on hard technology. © Springer-Verlag Berlin Heidelberg 2010.

Han J.,LIAONING Technical University | Han J.,Kailuan Group Ltd Liability Corporation | Zhang H.-W.,LIAONING Technical University
Meitan Xuebao/Journal of the China Coal Society | Year: 2010

Based on the analysis of spatial distribution of China's coal and gas outburst, the tectonic evolution and coal structure, tectonic, gas coal structure, and tectonic stress were analyzed in northeastern China, northern China and southern China coal accumulation area from the dynamic and historical perspective. Clarified the controlling of tectonic evolution to coal and gas outburst. At the last discussed the command pattern of coal and gas outburst of the northeastern China, northern China and southern China coal accumulation. Coal and gas outburst is closely related to active fault in northeastern China, but to coal structure in northern China and southern China.

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