Applied Mechanics and Materials Vols. 148-149

Abstract: Bone material is very complex in nature due to its anisotropic and hierarchical structure. Bone is weaker in shear as compared to tension and compression therefore shear properties of bone material are important to find out. Many researchers have applied different techniques to find out shear properties of bone material but these techniques either require such type of bone specimens which are difficult to prepare or provides limited information about the shear properties. Iosipescu shear test method has been applied in the present work to find out locational variation in shear properties of cortical bone. This technique seems to be very effective for the case of bone material and require less effort as compared to the other techniques applied by the other researchers in the previous reports.

Abstract: Along with the rapid development of electronic communication technology and the widely application of mobile phones, it is required to shorten the production period ,to lower production cost and to increase the competitive power. The traditional design method obviously cannot satisfy the requirement of production, but the application of Moldflow software can solve it ,which can analysis the product structure reasonably, to realize the optimization design of the parts; which can formulate rational production process parameters, such as the filling time and the holding time etc; which can analyze the warping ,bubble, lack of material common defects ,to optimize mold design; which can design the die structure, such as reasonable pouring system,to shorten the cycle of mold design ,to reduce production cost and enhance the competitiveness of enterprises.

Abstract: A simple integration scheme is presented for numerical integration in the extended finite element method(XFEM). In this scheme, the integral domain of common triangular mesh is converted to that of standard triangular mesh and the integral domain of standard triangular mesh is converted to that of quadrilateral mesh. By this transformation of integral domain, the strength intensity factors for straight crack are worked out. Finally, the accuracy of this method is analyzed by a typical example. It is concluded that the results obtained by new integral scheme are more accurate and simple than common Gaussian integration scheme.

Abstract: In order to improve the gaseous hydrogen storage kinetics of the Mg2Ni-type alloys, Ni in the alloy was partially substituted by M (M=Cu, Co). Melt-spinning technology was used for the preparation of the Mg20Ni10-xMx (M=Cu, Co; x=0, 1, 2, 3, 4) hydrogen storage alloys. The structures of the as-cast and spun alloys are characterized by XRD, SEM and TEM. The gaseous hydrogen absorption and desorption kinetics of the alloys were measured by an automatically controlled Sieverts apparatus. The results show that the as-spun (M=Cu) alloys hold a typical nanocrystalline structure, whereas the as-spun (M=Co) alloys display a nanocrystalline and amorphous structure, confirming that the substitution of Co for Ni facilitates the glass formation in the Mg2Ni-type alloy. The substitution of M (M=Cu, Co) for Ni engenders an insignificant effect on the hydrogen absorption kinetics of the alloys, but it markedly ameliorates the hydrogen desorption kinetics of the alloys. As the M (M=Cu, Co) content increase from 0 to 4, the hydrogen desorption ratio ( ) is enhanced from 27.7% to 58.9% for the as-spun (30 m/s) alloy (M=Cu), and from 27.7% to 70.2% for the as-spun (30 m/s) alloy (M=Co).

Abstract: In order to obtain flow rule and separation mechanism of garbage mixture particle in pneumatic separator, under the conditions of certain parameters and boundary, gas-solid two-phase flow mathematic model of garbage mixture particle was set up, FLUENT software was used to simulation and analyze the flow field of improved pneumatic separator, the separate track of particle in improved pneumatic separator was gained and performance of improved pneumatic separator was forecasted. Numerical simulation results show that the improved pneumatic separator has stable variation of pressure and velocity field. There not exist internal turbulence and back-mixing phenomenon and three particles with different qualities can be separated effectively. The numerical methods can be further optimized pneumatic separator and important theoretical foundation and technology method are provided for improving the structure and performance of pneumatic separator.

Abstract: Employing unique advantage of giant magnetostrictive strain of giant magnetostrictive material (GMM) for improving reference vibration amplitude, a novel bulk GMM solid MEMS gyroscope, which has small and simple structure and is capable of detecting 2-axis angular rate with improved sensitivity, is proposed. The device structure and operation principle of the gyroscope are presented. Using finite element method (FEM), modal analyses, for whole solid GMM cube and for bulk GMM cube composed of multilayer GMM plates, are conducted. The results show that the fourth order vibration mode for the former and the first order vibration mode with lower frequency of dozens of KHz for the latter were found to meet the working vibratory mode of the gyro sensor. This work of the paper provides theory foundation for structural optimization design and fabrication of the microgyroscope.

Abstract: Ternstroemia gymnnanthera is an important plant for industrial raw material of tanning. The systematic artificial breeding techniques are studied. The seeds and the cutting propagation had been carried out in our lab for two years,There is dormancy period of 3 to 4 months for the mature seeds.we found the dormancy is related to its seed coat and red aril. The seed’s nutrients are stored in the cotyledons. The seed coat artificially broken and GA3 (700mg/L) or NAA (100mg/L) treatment can promote seed germination rate. The seed germination is a good way for seedling nursery. The different treatments had done for cuttings to make the seedling nursery and the treatment with NAA (100mg/L) and ABT can significantly improve the cuttings survival rate of two years.Three wild populations of this species were studied in field. We found it adapted to sun environment better than the half shade or shade environment, as in the shade environment, it can not be normally flowering and bearing fruit.

Abstract: The paper proposed a de-noising method for non-stationary signals received by a small-size antenna array. By taking into consideration of the correlation of signals received by antennae which compose the antenna array, we could improve greatly the discovery probability of signal coefficients in time-frequency domain through taking advantage of the method of integration for signal detection. Meanwhile, under the assumption of Gaussian noise environment, the probability density functions of noise and signal after integration were also presented. In order to extract the coefficients for signal and reduce the Type I error further, an algorithm based False Discovery Rate (FDR) was put forward. Finally, a comparison between the detection performances before and after integration was made: under same rate of Type I error, the detection performance of signal after integration is improved significantly. And the effectiveness of the method was showed by experimental results as well.

Abstract: In this paper, research was focused on the carbide lime decomposition mechanism in pure N2 atmosphere by using thermo-gravimetric analysis with multi-heating rate method. Appling equal conversion rate method, activity energy E was calculated which was equal to 84.79 kJ/mol without proposing decomposition mechanism. A more accurate and reliable method based on multi-heating rate methods was put forward to deduce the mechanism function of above reaction, which was called “master plot methods”. Comparison was done between the theoretical master plots drawn by assuming various kinetic models and the experimental master plot, which allows us to select the probably appropriate kinetic model of the process under investigation. And the further detailed kinetic analysis was achieved as the knowledge of the kinetic model. The results are as follows: the reaction mechanism function f(α)=2.95(1-α)0.661 or G(α)=1-(1-α)0.339, the pre-exponential factor lnA=15.95. And the decomposition mechanism of carbide lime turned out to be the phase boundary shrinking sphere reaction.

Abstract: This article presents the approach of quasi LPV (Linear Parameter-Varying) modeling techniques for an air conditioning system of an electric vehicle. Vehicle air conditioning systems are strongly non-linear systems and it is a challenging task to get a precise real time model for control purposes. Therefore, an LPV method is first introduced to estimate the air conditioning system. Experimental results show that the LPV model delivers a very high accuracy for the COP (Coefficient Of Performance) estimation, that can’t be reached by traditional identification methods. Some discussion about the model structure and its application are presented and a non-linear LPV model structure similar to the Hammerstein structure is proposed.