Applied Mechanics and Materials Vols. 303-306

Abstract: When the characteristic sizes of materials and elements reduce to nanometers, the influence of surface energy becomes prominent in its mechanical behavior. In the frame of surface elasticity, the scattering of of plane compressional waves (P-waves) by a semi-cylindrical cavity embedded in an elastic half-plane is investigated in this paper. By using the wave function expansion method, we obtain the analytical solutions of elastci fields. The results show that surface energy has a significant effect on the diffractions of P-waves as the radius of the semi-cylindrical cavity shrinks to nanoscale. For incident waves with different frequencies, radius of semi-cylindrical cavity, the effects of surface elasticity on the dynamic stress concentration around the semi-cylindrical cavity are discussed in detail.

Abstract: The scattering of plane P waves by a nanosized semi-cylindrical inclusion embedded in an elastic half-plan has been studied in this paper. To account for the surface effect at nanoscale, the surface elasticity is also adopted. When the boundary condition at the straight edge of the half-plane is traction free, the analytical solutions of stress fields of the half plan with semi-cylindrical inclusion are expressed by employing a wave function expansion method. The results show that surface energy has a significant effect on the scattering of plane P waves as the radius of the semi-cylindrical inclusion shrinks to nanoscale. For incident waves with different frequencies, radius of semi-cylindrical inclusion, the effects of surface energy on the dynamic stress concentration near the semi-cylindrical inclusion are discussed in detail.

Abstract: This paper describes a one-step hydrothermal synthesis of rod-shaped HgTe nanocrystals (NCs). X-ray powder diffraction (XRD), field scanning electron microscopy (FE-SEM), transition electron microscopy (TEM) and energy-dispersive X-ray analysis (EDX) have been used to characterize the HgTe NCs. The length, diameter, surface roughness and the aspect ratio of the HgTe nanorods are well controlled through Te precursor, reaction time and reductant.

Abstract: Compared to other topological indices, molecular connectivity index has good structural selectivity and correlation.According to the molecule’s 2D and 3D topology file, we conducted research on the mol2 format file to consider how to convert the ASCII file into the adjacency matrix. Based on the adjacency matrix, we analyzed the relevant algorithm to calculate the molecules’ molecular connectivity index through adjacency matrix. As a molecular descriptor, the molecular connectivity index can be used in QSAR.

Abstract: 1-methyl-3-butyl Imidazole chloride is prepared by 1–methyl imidazole and chlorinated n-butane. The synthesis reaction of 1-methyl-3-butyl imidazole tetrafluoroborate is in the acetone. The solubility of NaNO₃ and BMIC in acetone is not large, but due to the insolubility in acetone of reaction product NaCl and continuous precipitation from the liquid phase in the reaction process, so as to promote the reaction continuously towards forward direction. The colorless transparent and odorless BMINO₃ are gotten. We use infrared spectrometer for the structure characterization, it is proved that we have gotten BMINO₃ room temperature ionic liquids. BMIC and BMINO₃ ionic liquids have better solubility in H₂O, ethanol, ethyl acetate, acetone, acetonitrile, and methanol, and is insoluble in the ether and cyclohexane.

Abstract: Gas dispersion and solid suspension in industrial size slurry bubble column reactors for producing sodium dichromate are simulated numerically by using of computational fluid dynamics (CFD). The Eulerian multi-fluid model and standard k-ε turbulence model are used to describe the flow behavior in bubble columns. The simulated results show that gas is easy to flow toward the centre of the bubble column and in relatively high local gas holdup there. Installing gas-re-distributors in the bubble column is favorable for gas dispersion. Solid suspension in the bubble columns under the operating condition we investigated is relatively uniform.

Abstract: The nutritional parameters of methamidophos degrading enzyme, which is isolated from soil from Daqing and identified as Staphylococcus Rosehbach, were studied by response surface methodology (RSM). Glucose, peptone and culture time were analyzed by Box-Behnken design for optimizing their concentrations in the medium and the effect of their mutual interaction on methamidophos degrading enzyme activity. Glucose and soybean protein were found in influencing the methamidophos degrading enzyme activity highly significant. Glucose and soybean protein also showed an effect on the methamidophos degrading enzyme activity in interaction with other variables. The optima values of the parameters obtained through RSM, 0.31% glucose, 0.09% peptone and culture time 72h were applied. Actual value of verifiable experimentation was that the degradation ratio of methamidophos degrading enzyme to methamidophos was 39.8% at the optima conditions.

Abstract: Cut tobacco was thermodynamics analyzed as infinitesimal volume, and the equation of energy conservation was built. The process of the burn front moving forward for 1 second(s) could be thermodynamics analyzed and another energy equation was also built. Then, the two equations were combined to get the smoldering velocity, which would be added into the mass, momentum, energy equation which was used to describe the whole burning process. The mass, momentum, energy equation was solved by the CFX software, and the results showed that: 1) After a cigarette ignited, the combustion process was accelerated firstly, then the process became slow and at last be at steady state. 2) Paper diffusivity play a critical role in determining the temperature of the smoldering cone, and the results were in good agreement with the experiment results.

Abstract: Submitted article deals with the impact of the cutting fluid´s pressure on the deviation from circularity. In submitted article an experiment is described when the pressure was changing from 15 to 25 bar in drilling of Al2O3 with ultrasound among other variables, feed and rotational speed. The aim of experiments was to define how the value of circularity of the hole is changing in different depths of machined hole. There is a dependence in USM process where the hole´s perimeter is rising with the depth of hole, however there was no knowledge in this problematics in RUM process. According to results from experiments it can be concluded, that the deviation from circularity is rising with the depth of a hole. The parameter influencing the deviation the most is cutting fluid´s pressure as was expected.

Abstract: A laboratory study was conducted to measure the coefficient of friction between the foot and the floor under three surface and two foot sliding speed conditions. A force platform was adopted to measure the ground reaction force (GRF) of the foot on the floor. The coefficient of friction was calculated as the ratio of vertical and horizontal GRF. Five male subjects were recruited. They were requested to slide their right foot on the tested floor which was mounted on the force platform. The results indicated that floor material, surface condition, and foot sliding speed were all significant factor affecting the COF. Ceramic tile had lower COF under all surface and sliding speed conditions as compared to steel, wood, and vinyl tiles.