After describing Japanese slow but steady progress and Chinese very rapid progress of high-speed railways, comparison and analysis of ways of development and those of specific components are discussed. By adding descriptions of European developments which are much different to Japanese, comparisons are made between Japanese and Chinese strong and weak points in order to contribute to the improvement of worldwide rail passengers’ transport including inferior aspect of both countries systems.

The contact force distribution between the core member and the external member of a buckling-restrained brace (BRB) is closely related to its deformation mode, and it directly affects the working state of the extended core and external restraining member. This study focuses on a pinned BRB with extended core as a research object and investigates the stress state of a BRB. Based on the specified core deformation modes and contact force distributions, the contact force and the bending moment distribution in the external member are deduced. Lastly, by considering the mechanical characteristics of the external member and extended strengthened core region (ESCR), their strength design criteria are established. In the theoretical derivation of the design method, the influence of some parameters is considered, including the initial geometrical imperfection of the external member, the gap between the core and the external member, the rigidity reduction of the restrained strengthened core region (RSCR), and the change of contact position. Finite element numerical verification of the corresponding theoretical derivation is discussed in detail in another paper as Part II (Jiang et al., 2015).

The theoretical derivation from Part I (Jiang et al., 2015) has obtained the core contact force and the bending moment distribution of the external member in the single-wave core deformation mode. In addition, the design criteria of the external member and the strengthened core region (SCR) have also been obtained based on the understanding of the mechanical characteristics of the buckling-restrained brace (BRB). Based on the theoretical results from Part I, this study conducts the corresponding finite element (FE) numerical verification, and the BRB parameter analysis is also performed when the core deforms as a single-wave deformation. The influence of nine parameters on the core contact force and the external member stress is investigated. These parameters include the flexural rigidity of external member, the initial imperfection of external member, the core thickness and its width-to-thickness ratio, the pinned connector length, the external member length, the length of restrained strengthened core region with uniform section and the height of the wing-plate of the SCR, as well as the gap between the core and the external member. Lastly, the 12 examples of BRBs that are designed according to the proposed design criteria are analyzed using FE simulation, and the reliability of the theoretical derivation is also verified.

The plane stress problem of beams is a typical one in elasticity theory. In this paper a new set of boundary conditions for the fixed end is proposed to improve the accuracy of the plane elasticity solution for beams with fixed end(s). Plane elasticity solutions are then derived for the cantilever beam, propped cantilever beam, and fixed-fixed beam. The new set of boundary conditions is constructed by combining two conventional ones with a parameter. The parameters for different kinds of beams are determined by minimizing the square sum of the longitudinal displacements through the thickness of the fixed end. Comparison with the results obtained by the finite element method (FEM) shows the efficiency of the new type of boundary conditions. When the beam is a deep one, it is found that different boundary conditions yield different errors, and the elasticity solution obtained by the new boundary conditions best approaches the FEM results.

The indirect chemical effects of fuel dilution by CO₂ on NO formation were investigated numerically in this paper. CH₄ doped with NH₃ was used as fuel, while CO₂ and O₂ were mixed as oxidant. The dilution effect of CO₂ was then investigated through adding extra CO₂ to the reaction system. An isothermal plug flow reactor was used. An unbranched chain reaction mechanism is proposed to illustrate the chemical effects of CO₂ on the H/O/OH radical pool and NO_x. Due to the reaction between CO₂ and H, extra NO will be formed in fuel-rich conditions, while NO will be inhibited in fuel-lean conditions and high CO₂ dilution conditions. The reaction affected the radical pools of OH, H, and O of the branched chain reaction, and then the formation and reduction of NO. The pool of H had the greatest effect on NO reduction. The results suggest that the indirect chemical effects on NO formation differ between diluted fuel oxy-fuel combustion conditions and normal oxy-fuel conditions.

The combustion of gasoline-air mixtures in a constant-volume combustion chamber with an initial condition of 0.1 MPa pressure and 363 K temperature is experimentally investigated with laser ignition generated by a Q-switched Nd:YAG laser (wavelengths of 532 and 1064 nm). Spark ignition is also tested, and the results are used as the benchmark. Combustion chamber pressure is measured by a piezoelectric pressure transducer, and recorded using a digital oscilloscope. When the equivalence ratio is swept from 1.2 to 1.8, laser and spark ignition show marginal differences in pressure rise rate and peak pressure. The maximum pressure rise rate and the maximum peak pressure are obtained at equivalence ratios of 1.6 and 1.8 for laser ignition and spark ignition, which are 39.4 MPa/μs and 0.68 MPa for the laser wavelength of 532 nm, 38.8 MPa/μs and 0.67 MPa for the laser wavelength of 1064 nm, and 38.1 MPa/μs and 0.67 MPa for spark ignition, respectively. When the equivalence ratio is reduced below 1.2, the pressure rise rate and peak pressure of the laser ignition are significantly higher than those of spark ignition, and the lean limit for laser ignition is also wider than that of spark ignition; therefore, laser ignition is more favorable for lean combustion. For both the laser and spark ignitions, the ignition energy demonstrated a limited impact on both the pressure rise rate and peak pressure. Heat release rate in the combustion chamber is calculated, and the results show that variations of heat release are in accordance with variations of the pressure history.

Global coal mining activity is increasing due to demands for cheap energy and the availability of large coal deposits around the world; however, the risks associated with conventional coal mining activities remain relatively high. Underground coal gasification (UCG), also known as in-situ coal gasification (ISCG) is a promising alternative method of accessing energy resources derived from coal. UCG is a physical-chemical-geotechnical method of coal mining that has several advantages over traditional mining, for example, its applicability in areas where conventional mining methods are not suitable and the reduction of hazards associated with working underground. The main disadvantages of UCG are the possibility of underground water pollution and surface subsidence. This work is focused on the latter issue. A thorough understanding of subsidence issues is a crucial step to implement UCG on a wide scale. Scientists point out the scarce available data on strata deformations resulting from UCG. The former Soviet Union countries have a long history of developing the science related to UCG and experimenting with its application. However, the Soviet development occurred in relative isolation and this makes a modern review of the Soviet experience valuable. There are some literature sources dealing with Soviet UCG projects; however, they are neither up-to-date nor focus on aspects that are of particular importance to surface subsidence, including geological profiles, strata physical-mechanical properties, thermal properties of geomaterials, and temperature spreading. The goal of this work is to increase the knowledge on these aspects in the English-speaking science community.