Applied Mechanics and Materials Vol. 472

Abstract: The anti-plane crack problem is studied in functionally graded piezoelectric materials (FGPMs). The material properties of the FGPMs are assumed to be the exponential function of y. The crack is electrically impermeable and loaded by anti-plane shear tractions and in-plane electric displacements. Similar to the Williams solution of homogeneous material, the high order asymptotic fields are obtained by the method of asymptotic expansion. This investigation possesses fundamental significance as Williams solution.

Abstract: In this present study, the gasification kinetics of rubber seed shell, high density polyethylene, and their mixtures (20/80 and 40/60 weight ratio of HDPE/RSS) are investigated using a non-isothermal thermogravimetric analysis (TGA) system at heating rate of 10 K/min in the temperature range of 323-1173 K. The argon gas is supplied at a flowrate of 100 ml/min and the steam is generated from superheater at 383 K. The steam is injected at flowrate of 300 μL/hour into the TGA system. The Criado and Coats-Redfern methods are used to investigate the reliability of the determined value of the activation energy, E_A from the experimental data of TGA. The interaction of solid-phase components based on the mentioned experimental conditions is also studied.

Abstract: Cassava dregs contain nearly 38.41% of starch, which has a similar structure to that of a starch. It was found that the cassava dregs would have the same function as the cationic starch if cationic groups were introduced. In this study, cationic cassava dregs were synthesized with the laboratory methods and characterized by FT-IR. The factors affect the retention and drainage was investigated. The result showed that, at a dosage of 1.0% of the cationic cassava dregs, the retention of fines was higher than 90%, best flocculation efficiency occurred at pH 8.5 when the dosage of cationic cassava dregs was 1.5%. Cationic cassava dregs had good resistance against moderate shear force, less affected by the conductivity, and it also showed a good strength properties.

Abstract: Er³⁺ doped SrMoO₄ (SrMoO₄:Er³⁺) and Er³⁺/Yb³⁺ co-doped SrMoO₄ (SrMoO₄:Er³⁺/Yb³⁺) particles were successfully synthesized by a cyclic microwave-assisted metathetic (MAM) route followed by heat treatment. The microstructures exhibited well-defined and homogeneous morphology with particles sizes of 100500 nm. With excitation at 980 nm, SrMoO₄:Er³⁺ and SrMoO₄:Er³⁺/Yb³⁺ particles exhibited a strong 525-nm emission band and a weak 550-nm emission band in the green region and a weak 655-nm emission band in the red region. The Raman spectra of SrMoO₄:Er³⁺ and SrMoO₄:Er³⁺/Yb³⁺ particles indicated the detection of additional strong peaks at both higher frequencies (564, 524, 456, and 403 cm^-1) and lower frequencies (294, 251, and 220 cm^-1).

Abstract: The co-precipitation method synthesized LiFePO₄/C composite cathode material combined with high temperature carbonization, the amount of carbon source added was characterized by XRD, SEM and other physical tests, as well as its electrochemical properties. The results show that the amount of carbon-coated has a certain influence on the properties of the materials. Which carbon-coated contents of 60% from the first discharge the specific capacity can reach 150.77mAh/g in the discharge rate of 0.1C, and has a retention rate of 90.74% in the discharge of 1C, which has to meet the needs of practical application .

Abstract: For a distributed PEMFC power station utilizing biogas as a source to produce hydrogen, deep desulfurization of the biogas is important. ZnO/γ-Al₂O₃ and CuO/γ-Al₂O₃ were prepared by an impregnation method, and their performances on CH₃SH removal in the biogas have been studied. Results showed that CuO/γ-Al₂O₃ is able to remove CH₃SH to below 10 ppb at 250-400 °C and has a sulfur capacity of 0.056 mmol g^-1 at 300 °C. Regarding to the desulfurization mechanism, it has been confirmed that the removal of CH₃SH with CuO/γ-Al₂O₃ is based on chemical adsorption. In the desulfurization, CH₄s dry reforming took place at above 250 °C, and the generated H₂ and CO reduced CuO to Cu₂O and Cu. Further, it was supposed that H₂S generates through the hydrogenation of CH₃SH at the presence of H₂.

Abstract: Resin concrete is a new material which can be made into machine bed instead of the traditional pieces of gray cast iron as the machine base, it can improve the dynamic stiffness of machine tools and the quality of machined parts, and extend the campaign life, reduce noise and improve efficiency. However, due to the long-term effect of load of the resin concrete, the elastic deformation occurs in its component, and the strain will increase over time. Thus it can affect the resin concretes service life, and the calculation of creep has become an urgent task in structure design and use, which should be taken seriously. In this paper, the bending creep properties of resin concrete beam were studied and analyzed by using four-point bending test method. The creep curve under different load levels were obtained, and the viscoelastic properties were analyzed.

Abstract: The wide range of applications of fiber-reinforced composites in numbers of engineering fields is demanding better understanding on its hydrothermal properties. Especially for those are applied under complex hydrothermal environment such as aircraft industry. However, most methods we used at the present are either complicated or demand high-cost. In this paper, a novel approach based on finite element method (FEM) is proposed to calculate the hydrothermal factor by supposing an original decrease in the laminates stiffness. The integrated strains, consisting of Room Temperature Dry (RTD) strain and FEM simulated strain with the Elevated Temperature Wet (ETW) strain, are used to make an estimate for the hydrothermal factor. Hence, this FEM approach with low cost can be used to calculate the hydrothermal factor without doing full-scale structural ETW experiments. Compared with experimental results of the notched compression and single-bolted joints, it can be concluded that the approach introduced in the present paper can predict excellently the determination scope of the hydrothermal factor reasonably even in structural scale.

Abstract: Based on the micro-structure, a mosaic model was established to obtain the stresses distribution of the C/C composite beam subjected to bending load. Then a subroutine for failure analysis was introduced to calculate the failure index of the composite beam. A corresponding laminate model was used to validate the calculation of the mosaic model. The results indicated that the method combining micro stresses and macro failure criterion was suitable for strength analysis of composite structure, which could be used in guiding the design of composite.

Abstract: Employing Metalorganic frameworks (MOFs) as precursor, a series of CuO/CeO₂ catalysts with welldispersed copper species were synthesized and applied for preferential CO oxidation in H₂rich stream. The high activity of the CuO/CeO₂ catalysts indicated that MOFs precursor played a key role in improving the dispersion of metal active sites.