The influence of the moisture content on the ignition and combustion characteristics of lignite single particles was studied using an ignition model of single coal particles with moisture and experimental investigations in a visual drop tube furnace under the temperature of 1300 K. The moisture content and the lignite particle size were varied within the ranges of 0-20% and 75-250 μm, respectively. The images of the combustion process illustrated that higher moisture content caused a significant ignition delay. The probability of homogeneous ignition was greatest when the particle size was 125-150 μm and the moisture content was 5%. An ignition model was employed to explain the mechanism of the influence of moisture content on the ignition and combustion characteristics, which embedded the chemical percolation devolatilization model to increase the accuracy of predictions. The predicted results show that there was an overlap in the release of moisture and volatile matter from the lignite particle during the combustion at a high heating rate. The devolatilization rate increases with the increase of moisture, which explains the increase in the probability of homogeneous ignition and fragmentation. Both particle size and moisture content have two-sided effects on the ignition mode, which causes the complexity and irregularity of the ignition mode of particles with moisture.

An investigation into the evolution of temperature and stress fields, as well as the phase transformation in marine steel EH36 during multi-pass welding, and their subsequent effects on Charpy impact toughness, remains in great lack. In this study, submerged arc welding (SAW) was employed to carry out multi-pass welding on EH36 steel plates, followed by the low-temperature toughness test of weldments. Comsol software version 6.2 and finite element analysis are utilized to simulate the evolution of the microstructure, temperature, and residual stress fields throughout the multi-pass welding process. As welding progressed, the heat absorption along the vertical direction was enhanced; in contrast, a decrease is observed in the horizontal direction away from the heat source. This complicated temperature history favors the bainite transformation in the vicinity to the heat source, whereas areas more remote from the weld zone exhibit a higher prevalence of acicular ferrite due to the reduced cooling rate. The concentration of residual stress is predicted to occur at the boundary of the melt pool and at the interface between the weld and the heat-affected zone, with the greatest deformation observed near the fusion line at the top surface of the model. Furthermore, multi-pass welding may alleviate the residual stress, especially when coupled with the formation of acicular ferrite upon cooling, leading to improved low-temperature impact toughness in regions remote from the heat source. These findings offer valuable insights for the design and optimization of multi-pass welding in future applications.

In this work, the aim is to predict biomass combustion characteristics based on the semiquantitative analysis of biomass functional group structural parameters. The structural parameters of biomass were calculated by Fourier transform infrared (FT-IR) spectroscopy. Then, a chemical percolation devolatilization model suitable for biomass was used to predict the pyrolysis process of biomass, and the influence of functional group structural parameters on the pyrolysis behavior was analyzed. The combustion characteristics of biomass were investigated by using a thermogravimetric analyzer and visual drop tube furnace. Finally, correlations between functional group structural parameters and combustion characteristics were established. The results show that biomass with a high content of hydroxyl groups (I _a1) preferentially generates H₂O at 150 °C, leading to a delay in ignition time. Long-chain aliphatic hydrocarbons (I _b1) exhibit lower thermal stability, and CH₄ and tar are released in 200–400 °C. This accelerates the reaction combustion rate and increases the likelihood of homogeneous ignition. The release rates of CO and CO₂ are related to the types of carbon–oxygen functional groups. The content of difficult-to-decompose ether bonds in corn stalks is as high as 33.97%, which does not easily decompose at low temperatures, leading to a long ignition delay time and a reduced probability of homogeneous ignition.

Thermosensitive nanogels are highly sensitive to temperature fluctuations, making precise thermal control critical for uniform particle formation and consistent product quality. This study introduces a TRIZ-guided reactor design that integrates material-level self-feedback heating with structurally homogenized heat transfer, shifting temperature regulation from conventional multi-point feedback to intrinsic physical adaptation. Experimental evaluation demonstrated that the optimized system reduced the maximum temperature difference from 6.5 °C to 3.2 °C and decreased the standard deviation from 3.9 °C to 1.8 °C, resulting in improved reaction stability. Correspondingly, monomer conversion increased from 90% to 95%, and the particle size distribution narrowed, with PDI decreasing from 0.32 to 0.18. The energy consumption per unit mass of reactant also decreased from 3.6 kJ·g⁻¹ to 2.5 kJ·g⁻¹. These results indicate that the TRIZ-based self-feedback approach effectively enhances temperature uniformity, reaction control, and energy efficiency, providing a transferable strategy for temperature-sensitive polymerization and nanomaterial synthesis.

Copper-containing steel is widely used in ship plates and other marine engineering fields due to its excellent mechanical properties and good weldability. However, in hydrogen-containing media environments, ship plate steel is prone to hydrogen embrittlement during service. Existing research primarily focuses on steel grades with copper content below 3 wt.%, while the diffusion and trapping behavior of hydrogen in ultra-high copper steel with copper content exceeding 3 wt.% remains unclear. Therefore, this study designed an ultra-high copper content steel with a copper content of 6.01%, and investigated the diffusion behavior of hydrogen in the test steel under different hydrogen charging current densities through microstructure characterization, slow strain rate tensile testing, electrochemical hydrogen permeation, and internal friction tests. The results indicate that with an increase in hydrogen charging current density, the anti hydrogen embrittlement performance of the test steel is significantly improved without deteriorating its mechanical properties. At the same time, the hydrogen trap density increased by 167%, with the irreversible hydrogen trap density increasing by 76.3%, and the reversible hydrogen trap density increased significantly by 537.9%. A large number of microstructures, such as phase boundaries, grain boundaries, and dislocations, have formed inside the material, which have reversible trapping effects on hydrogen, effectively suppressing the migration of hydrogen in the crystal structure and reducing the embrittlement phenomenon caused by hydrogen. This study expands the application potential of copper containing steel in the field of ocean engineering, providing important reference for the future development of high-strength hydrogen embrittlement resistant copper steel with ultra-high copper content.