Applied Mechanics and Materials Vols. 368-370

Abstract: The geometric and electronic structures of bornite (Cu₅FeS₄) were studied using the first-principle calculation based on density function theory. By analyzing the results, a mixed bonding state is found in bornite, which is a strong covalent bond with much weaker ionic bonds. The interaction between S and Fe is stronger than that between S and Cu. The main bonding orbitals are as follows: Cu: 3d¹⁰4s¹, S: 3s²3p⁴, and Fe: 3d⁶4s². Fe center is to be reduced receiving electrons in its 3d orbitals and the S center is mostly to be oxidized.

Abstract: The gelation behaviors and self-assembly of organogels composed of benzimidazole/benzothiazole derivatives and benzoic acid with single/multi-alkyl substituent chain in various organic solvents were investigated. Their gelation behaviors in 20 solvents were tested as new organic gelators. It showed that the number and length of alkyl substituent chains, and benzimidazole/benzothiazole segment, have played a crucial role in the gelation behavior of all gelator mixtures in various organic solvents. More alkyl chains in molecular skeletons in present gelators are favorable for the gelation of organic solvents. The length of alkyl substituent chains has also played an important role in changing the gelation behaviors and assembly states. Morphological studies revealed that the gelator molecules self-assemble into different aggregates from wrinkle, lamella, belt, to fiber with change of solvents.

Abstract: Based on the Finite Element Method ,a model has been built to study the impact of rigid pile composite foundation with lateral unloading,then obtained a conclusion about the horizontal displacement during excavating.

Abstract: (Na0.5K0.5)NbO3 with Bi0.5(Na0.97K0.03)0.5TiO3 with x≤0.05 has been prepared by the conventional mixed oxide process. X-ray diffraction analysis revealed that, during sintering, all the Bi(Na0.97K0.03)TiO3 diffuses into the lattice of (Na0.5K0.5)NbO3 to form a solid solution with a perovskite structure. A morphotropic phase boundary (MPB) between orthorhombic (O) and rhombohedral (R) was found at the composition 0.98(Na0.5K0.5)NbO3-0.02Bi0.5(Na0.97K0.03)0.5TiO3 [abbreviated as 0.98NKN-0.02BNKT] with correspondingly enhanced dielectric and piezoelectric properties. For 0.98NKN-0.02BNKT ceramics, the electromechanical coupling coefficients of the planar mode kp and the thickness mode kt reach 0.33 and 0.49, respectively, after sintering at 1100 oC for 3 h. The ratio of the thickness coupling coefficient to the planar coupling coefficient is 1.48. With suitable Bi0.5(Na0.97K0.03)0.5TiO3 concentration, a dense microstructure and good electrical properties are obtained.

Abstract: Pure crumb rubber asphalt mixture using dry process has certain requirement of mineral gradation with the potential disadvantage of uneven mixing under the traditional temperature. In this paper the gradation design of asphalt mixture Sup-13 mixed with TOR and crumb rubber using dry process was studied with the Superpave design method, pavement performance of asphalt mixture including high temperature stability, cracking resistance at low temperature and water stability was tested in the experiment. Results show that Superpave design method is suitable for the research on the asphalt mixture of TOR and rubber, with getting moving stability 3682 times/mm, failure strain 2573.8με, residual stability 84.8% and the ratio of freeze-thaw splitting 80.1%. The performance is so good to meet the requirements for asphalt pavement performance.

Abstract: Multi-material ALE method combines the advantages of Lagrangian and Eulerian methods, avoids mesh distortion of the Lagrangian method, and eliminates moving boundary problems of the Euler method. A numerical simulation of blast-induced craters in geotechnical medium was performed within the frame of LS-DYNA by multi-material ALE method. The simulated crater which coincides with the empirical data from CONWEP was observed in post processing by the flow of material. This demonstrates that the multi-material ALE method is an effective way to simulate blast-induced craters in geotechnical medium.

Abstract: The probability distribution of the filament number of each cocoon layer (FNCL) in the raw silk by fixed number of cocoons reeling process was discussed. The probability distribution and statistic characteristic in stable reeling state were given. Computer simulation of reeling process was undertaken to verify the applicability and theoretical results. The model of stochastic process and the analysis results possess universality.

Abstract: Flue gas desulfurization gypsum (FGD gypsum) was irradiated with microwave, it could be changed calcined gypsum from flue gas desulfurization (CGD). The microwave respectively irradiated five groups FGD gypsum at 100-110°C, 110-120°C, 120-130°C, 130-140°C and 140-150°C, then the fineness and setting time were respectively measured, and compressive/flexural strength were also determined after 2 hours. Experiments show that, CaSO4·0.5H2O crystal of CGD would be more quantity and bigger volume with irradiation temperature increasing. The reason was considered that there were special effect of microwave irradiation to calcium sulfate crystalsthat by scanning electron microscope, and found the Ca, S, O and other elements in cylindrical crystal by Edax. The formation mechanism of CaSO4·0.5H2O crystal by microwave irradiation is different from traditional CaSO4·0.5H2O crystal formation theories.

Abstract: Mixture experimental design was applied to determine the optimal mixture for composites between rubberwood flour (RWF) and recycled polypropylene (rPP). Experiments were conducted based on a D-optimal mixture design and analyzed using response surface methodology. Analysis of variance revealed that compositions including rPP, RWF, maleic anhydride grafted polypropylene (MAPP), and ultraviolet (UV) stabilizer significantly affected hardness property. Contour plots of the response surface demonstrated that an increase of RWF content steadily enhanced hardness value, but hardness property sharply decreased with an increase of rPP loading. An addition of the UV stabilizer in the composites showed a slight decrease of the hardness value. This result recommends that amount of UV stabilizer used should be minimized. With this experimental design, the optimal formulation of rPP/RWF composites found was 50.0 wt% rPP, 45.0 wt% RWF, 3.9 wt% MAPP, 0.1 wt% UV stabilizer, and 1.0 wt% Lubricant.

Abstract: The extensive use of plastic film has caused serious environmental pollution. In this paper, the fully degradable cotton mulching film was produced from waste cotton fiber by wet papermaking process. The breaking strength, tearing strength, degradation rate, transparency, air and moisture permeability of the cotton film samples were tested and analyzed. The results show that the cotton mulching film has better mechanical properties, light transmittance, and excellent degradation characteristics.