[en] Measurement of curvature and twist is an important aspect in the study of object deformation. In recent years, several methods have been proposed to determine curvature and twist of a deformed object using digital shearography. Here we propose a novel method to determine the curvature and twist of a deformed object using digital holography and a complex phasor. A sine/cosine transformation method and two-dimensional short time Fourier transform are proposed subsequently to process the wrapped phase maps. It is shown that high-quality phase maps corresponding to curvature and twist can be obtained. An experiment is conducted to demonstrate the validity of the proposed method

[en] Based on analytical theory of anisotropy, distributions of thermal distortion and temperature field within a diode-end-pumped rectangular Nd:YVO4 laser crystal are investigated. A thermal model that matches the actual working state of the laser crystal is established by analyzing the working characteristics of the Nd:YVO4 laser crystal. A novel method, to the best of our knowledge, is adopted to solve the heat conduction equation of the anisotropic medium. General solutions of the temperature field, thermal strain field, and thermal distortion field of the Nd:YVO4 crystal are obtained. The effect of anisotropic thermal parameters on the thermal strain field of the Nd:YVO4 laser crystal is also analyzed quantitatively. Research results show that a maximum temperature rise of 244.9 deg. C and a maximum thermal distortion of 1.99 μm can be obtained in the center of the pump face when the Nd:YVO4 laser crystal doped with 0.5 at. % Nd3+ isdiode end pumped in the center of the front end face with 15 W output power. This method can be applied to other thermal analyses of laser crystals and offers a theoretical basis to solve thermal problems effectively in the laser system

[en] The effects of temperature on the discharge and hydrogen evolution of lithium anode in 4 M (mol L⁻¹) LiOH solutions were investigated via hydrogen collection, polarization and SEM (scanning electron microscope). It was found that the hydrogen evolution rate is low below 30 °C with low discharge current density and the discharge current density is high over 30 with high hydrogen evolution rate. The lithium anode shows the better electrochemical performance with high discharge current density, low hydrogen evolution, and less porous film at 30 °C at 0.94 m s⁻¹ in 4 M LiOH solutions

[en] This paper develops a relative entropy method to measure non-exponential random data in conjunction with fractional order moment, logarithmic moment and tail statistics of Mittag–Leffler distribution. The distribution of non-exponential random data follows neither the exponential distribution nor exponential decay. The proposed strategy is validated by analyzing the experiment data, which are generated by Monte Carlo method using Mittag–Leffler distribution. Compared with the traditional Shannon entropy, the relative entropy method is simple to be implemented, and its corresponding relative entropies approximated by the fractional order moment, logarithmic moment and tail statistics can easily and accurately detect the non-exponential random data. - Highlights: • A relative entropy method is developed to measure non-exponential random data. • The fractional order moment, logarithmic moment and tail statistics are employed. • The three strategies of Mittag–Leffler distribution can be accurately established. • Compared with Shannon entropy, the relative entropy method is easy to be implemented

[en] Based on the theory of semianalytical thermal analysis, the temperature field and thermal lens effects within a diode-end-pumped Nd:YAG rods were investigated. A general expression of the temperature field within Nd:YAG rods was obtained through the analysis of a diode-end-pumped Nd:YAG rod, using what we believe to be a new method to solve a heat conduction equation of isotropic material. Calculating the thermal focal length within the diode-end-pumped Nd:YAG rods was done by an analysis of the additional optical path differences caused by heat, which was in good agreement with experimental results. These results show that the maximum temperature on the pump face of Nd:YAG rods is51.9 degree sign C and the thermal focal length is22.4 cmwhen the output power of the diode laser is 10 W. Under the same conditions, the experimental value of the thermal focal length is21.0 cm. The difference between the theoretical analysis and the experimental result is only 6.7%. Results from this work can provide the theoretical basis for the optimized design of diode-end-pumped all-solid-state lasers

[en] The triple differential cross section for the electron-impact ionization of atomic hydrogen is analysed in a coplanar geometry by using the Coulomb-projected-eikonal approximation, where the two outgoing electrons are considered to be in uncorrelated Coulomb-continuum states. The scattering amplitude for the ionization is expressed as a three-dimensional integral in real space. A comparison is made with the experimental data and with results of other approximation methods. It is found that the method proposed here has some advantage over the conventional partial-wave technique and provides a better description both for the binary recoil collisions in the small momentum transfer condition. (author)

[en] Highlights: • The combined Rankine power and the absorption cooling cycles is investigated. • EES software is utilized to perform the parametric analyses. • The results represent the detailed major effects on the exergy efficiency. • The Genetic algorithm has been used to optimized the combined cycle. - Abstract: This study investigates the combined Rankine power and the absorption cooling cycles. The working fluid used in this cycle is the binary liquid mixture of water and ammonia. It produces both refrigeration and power simultaneously via a single heat source. Parametric analysis has been adopted to evaluate the thermodynamic parameters effects on the operation of the combined cycle where the Engineering Equation Solver (EES) is utilized. The obtained results show that environmental temperatures, heat source, refrigeration, inlet pressure, and temperature, and the density of the ammonia-water dilution have major effects on the exergy efficiency, the refrigeration output, and the net power of the system. In order to obtain the maximum exergy and thermal efficiencies, the optimization of the combined cycle has been performed via the genetic algorithm.

[en] Phase space cuts are implemented by inserting Heaviside theta functions in the integrands of momentum-space Feynman integrals. By directly parametrizing theta functions and constructing integration-by-parts (IBP) identities in the parametric representation, we provide a systematic method to reduce integrals with cuts. Since the IBP method is available, it becomes possible to evaluate integrals with cuts by constructing and solving differential equations.

[en] The Compound Strip Method is applied to the buckling analysis of ring-stiffened cylindrical shells under hydrostatic pressure. The eccentricity of stiffeners is taken into account. Numerical examples are given to illustrate the high accuracy of this method. Comparisons are made between buckling loads of shells stiffened by traditional T-shaped stiffeners and the hat-shaped stiffeners. (author)

[en] This paper surveys the latest advances of the first author's group on the three new methodologies of fractional and fractal derivatives modeling to meet the increasing and challenging demands in scientific and engineering communities. Firstly, the structural fractal was proposed as a generalization of the Euclidean distance. Using the structural metric, the structural derivative approach was derived as a significant extension of the global fractional calculus and the local fractional derivative approaches to tackle the perplexing modeling problems. The classical derivative describes the change rate of a certain physical variable with respect to time or space, which rarely takes into account the significant influence of mesoscopic time-space metric of a complex system on its physical behaviors. The structural function plays a central role in this new strategy as a kernel transform of underlying time-space structural metric of physical systems. Secondly, we employed the fundamental solution or probability density function of statistical distribution which can describe the problem of interest to construct the implicit calculus governing equation. The ‘implicit’ suggests that the explicit calculus expression of this governing equation is difficult to derive and not required. The fundamental solution or potential function of calculus governing equation and corresponding boundary conditions are sufficient to do numerical simulation. We call this strategy the implicit calculus equation modeling. Thirdly, based on the implicit calculus equation modeling approach, we introduced the concept of fundamental solution on fractal and consequently defined the fractal differential operator to describe various mechanical behaviors of fractal materials. Fractal calculus operator significantly extends the application scope of the classical calculus modeling approach under the framework of continuum mechanics. This is also a step-forward advance of the fractal derivative proposed earlier by the first author. To demonstrate the structural derivative application, we applied the inverse Mittag-Leffler function as the structural function to model ultraslow diffusion of a random system of two interacting particles. On the other hand, this paper uses the fractional Riesz potential as the fundamental solution to establish the implicit calculus equation of fractional Laplacian modeling the power law behaviors of steady heat conduction in multiple phase material. Finally, by using the singular boundary method, we made numerical simulation of the fractal Laplacian equation for phenomenological modeling potential problems in fractal media. Numerical experiments show that all the three new methodologies are feasible mathematical tools to describe complex physical behaviors.