Evaluation of the stress singularities of plane V-notches in bonded dissimilar materials

According to the linear theory of elasticity, there exists a combination of different orders of stress singularity at a V-notch tip of bonded dissimilar materials. The singularity reflects a strong stress concentration near the sharp V-notches. In this paper, a new way is proposed in order to determine the orders of singularity for two-dimensional V-notch problems. Firstly, on the basis of an asymptotic stress field in terms of radial coordinates at the V-notch tip, the governing equations of the elastic theory are transformed into an eigenvalue problem of ordinary differential equations (ODEs) with respect to the circumferential coordinate h around the notch tip. Then the interpolating matrix method established by the first author is further developed to solve the general eigenvalue problem. Hence, the singularity orders of the V-notch problem are determined through solving the corresponding ODEs by means of the interpolating matrix method. Meanwhile, the associated eigenvectors of the displacement and stress fields near the V-notches are also obtained. These functions are essential in calculating the amplitude of the stress field described as generalized stress intensity factors of the V-notches. The present method is also available to deal with the plane V-notch problems in bonded orthotropic multi-material. Finally, numerical examples are presented to illustrate the accuracy and the effectiveness of the method

Solid lipid dispersion of calcitriol with enhanced dissolution and stability

AbstractSolid dispersion of calcitriol with lipophilic surfactants and triglycerides was developed by melt-mixing method to modify the release and enhance stability of the drug. The solid dispersions were characterized by differential scanning calorimetry (DSC), hot stage polarized optical microscopy (HSPM), infrared spectroscopy (FTIR) and stability studies. The solid dispersion significantly enhanced the stability of calcitriol, which could be attributed to the high antioxidant activity of the solid lipid dispersion. The rapid dissolution rate from the solid dispersion was attributed to the amorphous or solid solution state of drug with improved specific surface area and wettability than the drug crystals. Therefore, solid dispersion of calcitriol with d-a-tocopheryl polyethylene glycol 1000 succinate (TPGS) offers a good approach to modify the release and enhance stability of calcitriol. The influence of lipophilic solid dispersion on drug bioavailability needs further investigation

Technique of quantum state transfer for a double Lambda atomic beam

The transfer technique of quantum states from light to collective atomic excitations in a double $\Lambda$ type system is extended to matter waves in this paper, as a novel scheme towards making a continuous atom laser. The intensity of the output matter waves is found to be determined by the initial relative phase of the two independent coherent probe lights, which may indicate an interesting method for the measurement of initial relative phase of two independent light sources.Comment: 5 pages, 2 figure