The effect of T-stress on crack–inclusion interaction under mode I loading

A closed-form solution has been developed to predict the effect of T-stress on the crack–inclusion interaction. As validated by several numerical examples, the approximate solution has satisfactory accuracy for different inclusion shapes and modulus ratios between inclusion and matrix under different T-stress levels. Thus the role of T-stress in crack–inclusion interaction can be predicted quantitatively.     

Reconstruction of velocity fields from wall pressure measurements in a shock wave/turbulent boundary layer interaction

We present here experimental results in a shock wave/turbulent boundary layer interaction at Mach number of 2.3 impinged by an oblique shock wave, with a deflection angle of 9.5°, as installed in the supersonic wind tunnel of the IUSTI laboratory, France. For such a shock intensity, strong unsteadiness are developing inside the separated zone involving very low frequencies associated with reflected shock motions.The present work consists in simultaneous PIV velocity fields and unsteady wall pressure measurements. The wall pressure and PIV measurements were used to characterize the pressure distribution at the wall in an axial direction, and the flow field associated. These results give access for the first time to the spatial-time correlation between wall pressure and velocity in a shock wave turbulent boundary layer interaction and show the feasibility of such coupling techniques in compressible flows. Linear Stochastic Estimation (LSE) coupled with Proper Orthogonal Decomposition (POD) has been applied to these measurements, and first results are presented here, showing the ability of these techniques to reproduce both the unsteady breathing of the recirculating bubble at low frequency and the Kelvin–Helmholtz instabilities developing at moderate frequency.     

A visual reference direction approach to solving discrete multiple criteria problems

In this paper, we propose a new visual interactive method for solving discrete multiple criteria problems. The method is based on the use of a reference direction, which is determined by the aspiration levels for the criteria specified by the decision maker. The reference direction is projected onto the set of efficient alternatives. A subset found in this way is presented to a decision maker in a visual form using computer graphics. He can choose any efficient alternatives he pleases.We need notmake any assumptions about the properties of the utility function.The method has been implemented on an IBM/PC1 microcomputer. The name of the program is Vimda (a Visual Interactive Method for Discrete Alternatives).     

Constructing Modular Forms from Harmonic Maass Jacobi Forms

Czechoslovak Mathematical Journal - We construct a family of modular forms from harmonic Maass Jacobi forms by considering their Taylor expansion and using the method of holomorphic projection. As...     

Separation and Sensitive Analysis of Chlorophenols by MEEKC

A new microemulsion electrokinetic chromatographic method has been established for separation and sensitive analysis of the three chlorophenols 2-chlorophenol, 4-chlorophenol, and 2,4-dichlorophenol. The optimum microemulsion system was 15 mM SDS, 112 mM n-butanol, and 10 mM n-octane in 20 mM sodium tetraborate (pH 9.0). Under the optimum conditions, baseline separation was achieved within 8 min. The method was used for analysis of a real water sample previously pretreated by SPE. The linear ranges, precision of migration time and peak area, and limits of detection (LOD) were in the ranges of 0.5–50 μg L^?1, 4.85–9.75%, 0.49–0.706% (n = 6), and 0.6–1 μg L^?1, respectively, for the three chlorophenols.     

Abnormal upconversion luminescence from Yb3+ doped and Tb3+/Yb3+ codoped high silica glasses induced by intrinsic optical bistability

Upconversion luminescence (UCL) properties from Yb³⁺ doped and Tb³⁺/Yb³⁺ codoped high silica glasses excited by a 980 nm laser diode are investigated. The ln–ln plots of the UCL intensity versus laser power show abnormal relations: the slopes are larger than those reported in other papers. When tuning the laser power up and down successively, intrinsic optical bistability of Yb³⁺ ions is observed at room temperature in the visible and infrared range without external cavity. And this nonlinear effect induces the abnormal UCL phenomena.     

Versal unfoldings of predator-prey systems with ratio-dependent functional response

In this paper we study the versal unfolding of a predator-prey system with ratio-dependent functional response near a degenerate equilibrium in order to obtain all possible phase portraits for its perturbations. We first construct the unfolding and prove its versality and degeneracy of codimension 2. Then we discuss all its possible bifurcations, including transcritical bifurcation, Hopf bifurcation, and heteroclinic bifurcation, give conditions of parameters for the appearance of closed orbits and heteroclinic loops, and describe the bifurcation curves. Phase portraits for all possible cases are presented.     

The lowest order solution of the crack–inhomogeneity interaction for mode I crack

The lowest order solution to crack–inhomogeneity interaction is derived for mode I crack. The basic solution evaluates the variation of near-tip stress intensity factors induced by an inhomogeneity of arbitrary shape. A set of simplified forms of the basic solution is also obtained for several special inhomogeneity shapes. As validated by numerical examples, the approximate solutions have good accuracy.     

3D lower bound bearing capacity of smooth rectangular surface footings

This paper describes a technique for computing lower bound limit bearing capacity of rectangular surface footings. A perfectly rigid plastic model is adopted to describe the property of soil materials. The bearing capacity of footing is regarded as the objective function in this method, subject to the stress boundary condition, stress discontinuity equilibrium condition, stress equilibrium condition and yield condition. By solving a non-linear optimization problem, i.e., searching the maximum value of objective function, the bearing capacity of smooth surface rectangular footing and the corresponding 3D stress field are obtained.