Advanced Materials Research Vols. 652-654

Abstract: In order to find the change characteristics of wheat stem lodging under the rectangle wind load, wheat stem models were set up which include 5 inter-nodes, and then the process of wheat stem lodging were simulated by finite element software ANSYS/LS-DYNA. The simulation results show that the lodging is related to impulse of the rectangle wind load. The smaller the impulse is, the more difficultly the stem lodging happen. Along the entire stem axis, the maximum stress value occurs in the ovalization area, the stress values are smaller in the other area. The study results provide some references for the research on high yield cultivation and lodging resistance of wheat and plant stem processing.

Abstract: The validated finite element method (FEM) was applied to the calculation of local impedance of viscoelastic sample in the acoustic tube. The acoustic impedance of viscoelastic material was calculated by three methods on the basis of numerical acoustic field computed by fluid-structure coupling method and the structure itself. The comparisons of calculation results illustrate that acoustic impedance is the inherent attribute of material.

Abstract: FeS solid lubrication duplex layer was prepared on the surface of 45 steel by ion nitrocarburizing and ion sulphurizing process. The sulphide grains in micron and nano scale and holes distributing equably on the duplex layer. The duplex layer is composed of FeS, FeS2 and Fe3N. Under liquid paraffin oil with 0.2wt%n-Fe3O4 lubricating, the synergistic effect between n-Fe3O4 and the duplex layer is produced, and the chemical reaction films including sulphide, sulphate and nitride is formed, which makes the friction factor of the duplex layer keep being the lowest and about 0.075, and the volume loss is reduced by 91% than that of the plain surface, and reduced by 89% and 21% than that of the sulphurized surface and the nitrocarburized surface, respectively.

Abstract: The crevice corrosion behaviors of X52 carbon steel in two typical Cl--containing solutions were investigated by electrochemical noise and electrochemical impedance spectroscopy. Results show that oxygen concentration difference leads to the coupled current in NaCl + NaHCO3 solution while HAc concentration difference causes the coupled current in NaCl solution saturated with CO2 in the presence of HAc. There exists an apparent incubation stage during the crevice corrosion process of X52 carbon steel in the former. However, no obvious incubation period of crevice corrosion can be observed in the latter. Micrography shows that the crevice corrosion occurs indeed and the corrosion inside the crevice is not uniform.

Abstract: This paper firstly introduced the stress dispersion mechanism of the warp knitted space fabric, and then tested the stress dispersion effect of the warp knitted space fabric and sponge (PU foam) with the same thickness. The results show that the warp knitted space fabric can effectively disperse the compression, and the dispersion effect can be increased with the increase of the thickness in a specified limit.

Abstract: Using Near-infrared Spectroscopy developed a complete set of method of qualitative analysis for far-infrared fiber.It is able to do a qualitative analysis for the far-infrared fiber quickly and accurately. Experiments using Near-infrared Spectroscopy, a total of 10 samples were collected from different varieties of polypropylene, polyester, far-infrared polypropylene and far-infrared polyester. This experiment created the far-infrared polypropylene qualitative model and the far-infrared polyester qualitative model.They can correctly identify the polypropylene and far-infrared polypropylene, polyester and far-infrared polyester.

Abstract: Inductively coupled plasma atomic emission spectroscopy was applied to the determination of boric anhydride in ascharite ores. Pretreatment method, reagents used for acid decomposition and the interferences from matrix and coexistent elements were discussed in details respectively. The analytical spectral lines were selected while experimental parameters were optimized. The results indicated that after the samples were completely dissolved and collected with hydrochloric acid (1+1) in a sealed container with a reflux condenser by the low-temperature heating method, they could be directly analyzed and determined with ICP-AES at optimized operating parameters. The relative standard deviation of the method is less than 1.4% within the measurement range of 0.1% ~ 40% and the recovery rate is in the range of 98.1% ~ 101.0%. The method was proved satisfactory with wide linear range, low detection limit and also high sensitivity and accuracy.

Abstract: Cationic Gemini surfactant concentration, the inorganic salts added and the pH value of surface tension obtained cationic gemini surfactant critical micelle concentration is 0.4mmol / L;by adding three kinds of inorganic salts NaCl, MgCl2, and Na2SO4 ,which Na2SO4 has the greatest impact on surface tension, followed by MgCl2.The surface minimum tension of the pH ranged from 9 to 11 , indicating that the surface activity of cationic gemini surfactants achieved the highest.

Abstract: Concrete is usually described as a three-phase material, where matrix, aggregate and interface zones are distinguished. The beam lattice model has been applied widely by many investigators to simulate fracture processes in concrete. Due to the extremely large computational effort, however, the beam lattice model faces practical difficulties. Moreover, real fracture processes are 3D and not 2D. In our investigation, a new 3D lattice called generalized beam (GB) lattice is developed to reduce computational effort. Numerical results obtained by the model are in agreement to what are observed in tests. The 3D effects of the particle content on the peak load and ductility are discussed as well as the 3D fracturing phenomenon.

Abstract: This paper describes an analytical formulation and a numerical solution of the elastic dynamic problems of non-homogeneous poroelastic moderately thick shells of revolution saturated in viscous fluid. The porosity and porous diameter of the material are assumed to be continuously varied along the shell thickness. The equations of motion and the relations between strains and displacements are derived from the Reissner-Naghdi shell theory. As the constitutive relations, the consolidation theory of Biot for models of fluid-solid mixtures is employed. The flow of viscous fluid through a porous elastic solid is governed by Darcy's law. In the numerical analysis of the fundamental equations an usual finite difference form is employed for the spatial derivatives and the inertia terms are treated with the backward difference formula proposed by Houbolt. As a numerical example, the simply supported cylindrical shell under a semi-sinusoidal internal load with respect to time is analyzed. Numerical computations are carried out by changing porosity and mean void radius along the shell thickness, and the variations of pore pressure, displacements and internal forces with time are analyzed.