Alternate path (AP) method is the most widely used method for the progressive collapse analysis, and its application in frame structures has been well proved. However, the application of AP method for other structures, especially for cable-stayed structures, should be further developed. The four analytical procedures, i.e., linear static, nonlinear static, linear dynamic, and nonlinear dynamic were firstly improved by taking into account the initial state. Then a cable-stayed structure was studied using the four improved methods. Furthermore, the losses of both one cable and two cables were discussed. The results show that for static and dynamic analyses of the cable-stayed bridges, there is large difference between the results obtained from simulations starting with either a deformed or a nondeformed configuration at the time of cable loss. The static results are conservative in the vicinity of the ruptured cable, but the dynamic effect of the cable loss in the area farther away from the loss-cable cannot be considered. Moreover, the dynamic amplification factor of 2.0 is found to be a good estimate for static analysis procedures, since linear static and linear dynamic procedures yield approximately the same maximum vertical deflection. The results of the comprehensive evaluation of the cable failure show that the tread of the progressive failure of the cable-stayed bridges decreases when the location of the failed cables is closer to the pylon.

This paper presents the explosion cratering effects and their propagation laws of blast waves in dry standard sands using a 450 g-t geotechnical centrifuge apparatus. Ten centrifuge model tests were completed with various ranges of explosive mass, burial depth and centrifuge accelerations. Eleven accelerometers were installed to record the acceleration response in sand. The dimensions of the explosion craters were measured after the tests. The results demonstrated that the relationship between the dimensionless parameters of cratering efficiency and gravity scaled yield is a power regression function. Three specific function equations were obtained. The results are in general agreement with those obtained by other studies. A scaling law based on the combination of the π terms was used to fit the results of the ten model tests with a correlation coefficient of 0.931. The relationship can be conveniently used to predict the cratering effects in sand. The results also showed that the peak acceleration is a power increasing function of the acceleration level. An empirical exponent relation between the proportional peak acceleration and distance is proposed. The propagation velocity of blast waves is found to be ranged between 200 and 714 m/s.

Combustion kinetic parameters (i.e., activation energy and frequency factor) of coal have been proven to relate closely to coal properties; however, the quantitative relationship between them still requires further study. This paper adopts a support vector regression machine (SVR) to generate the models of the non-linear relationship between combustion kinetic parameters and coal quality. Kinetic analyses on the thermo-gravimetry (TG) data of 80 coal samples were performed to prepare training data and testing data for the SVR. The models developed were used in the estimation of the combustion kinetic parameters of ten testing samples. The predicted results showed that the root mean square errors (RMSEs) were 2.571 for the activation energy and 0.565 for the frequency factor in logarithmic form, respectively. TG curves defined by predicted kinetic parameters were fitted to the experimental data with a high degree of precision.

Staggered pattern perforations are introduced to isolated isothermal plates, vertical parallel isothermal plates, and vertical rectangular isothermal fins under natural convection conditions. The performance of perforations was evaluated theoretically based on existing correlations by considering effects of ratios of open area, inclined angles, and other geometric parameters. It was found that staggered pattern perforations can increase the total heat transfer rate for isolated isothermal plates and vertical parallel plates, with low ratios of plate height to wall-to-wall spacing (H/s), by a factor of 1.07 to 1.21, while only by a factor of 1.03 to 1.07 for vertical rectangular isothermal fins, and the magnitude of enhancement is proportional to the ratio of open area. However, staggered pattern perforations are detrimental to heat transfer enhancement of vertical parallel plates with large H/s ratios.

The volume of fluid (VOF) formulation is applied to model the combustion process of a single droplet in a high-temperature convective air free stream environment. The calculations solve the flow field for both phases, and consider the droplet deformation based on an axisymmetrical model. The chemical reaction is modeled with one-step finite-rate mechanism and the thermo-physical properties for the gas mixture are species and temperature dependence. A mass transfer model applicable to the VOF calculations due to vaporization of the liquid phases is developed in consideration with the fluctuation of the liquid surface. The model is validated by examining the burning rate constants at different convective air temperatures, which accord well with experimental data of previous studies. Other phenomena from the simulations, such as the transient history of droplet deformation and flame structure, are also qualitatively accordant with the descriptions of other numerical results. However, a different droplet deformation mechanism for the low Reynolds number is explained compared with that for the high Reynolds number. The calculations verified the feasibility of the VOF computational fluid dynamics (CFD) formulation as well as the mass transfer model due to vaporization.

In this study, an experimental setup is designed and built to investigate the feasibility and performance of the proposed dual-mode cascade refrigeration cycle. The apparatus can be operated in two modes: dual-stage mode and single-stage mode such that the low temperature cycle (LTC) can be operated together with the high temperature cycle (HTC) or can run independently. Experimental results validate the feasibility of independent operation of LTC. The performance of the independent operation of LTC mode is theoretically investigated using experimental data as bases. Detailed suggestions are made for the improvement of the coefficient of performance (COP) of the experimental system. Theoretically, high COP of the cycle provides excellent application for the presented refrigeration cycle.

This paper deals with a multi-objective parameter optimization framework for energy saving in injection molding process. It combines an experimental design by Taguchi’s method, a process analysis by analysis of variance (ANOVA), a process modeling algorithm by artificial neural network (ANN), and a multi-objective parameter optimization algorithm by genetic algorithm (GA)-based lexicographic method. Local and global Pareto analyses show the trade-off between product quality and energy consumption. The implementation of the proposed framework can reduce the energy consumption significantly in laboratory scale tests, and at the same time, the product quality can meet the pre-determined requirements.

The synthesis of methanol and dimethyl ether (DME) from CO hydrogenation has been investigated on Cu-based catalysts. A series of Cu/ZnO/Al₂O₃ catalysts were prepared using a solvent-free routine which involved a direct blend of copper/zinc/aluminum salts and citric acid, followed by calcination at 450 °C. The calcination processes were monitored using thermogravimetry differential scanning calorimetry (TG-DSC). Catalysts were further characterized using N₂ adsorption, scanning electronic microscopy (SEM), X-ray diffraction (XRD), N₂O oxidation followed by H₂ titration, and temperature-programmed reduction with H₂ (H₂-TPR). The reduction processes were also monitored with in-situ XRD. The physicochemical properties of catalysts depended strongly on the types of precursor salts, and catalysts prepared using Al acetate and Cu nitrate as starting materials had a larger surface area, larger exposed metallic copper surface area, and lower reduction temperature. The CO hydrogenation performances of these catalysts were compared and discussed in terms of their structures. Catalysts prepared with copper nitrate, zinc and aluminum acetates exhibited the highest catalytic activity.