CSA/GFRC is an advanced composite material possessed with great ductility and durability. However, its bending performance and fibre condition, as well as intrinsic microstructural changes, under elevated temperature have not been understood so far. XRD was applied in this study to investigate the hydration mechanism of CSA cement under 50°C, 70°C, and 80°C. Bending performance was carried out to test the toughness of CSA/GFRC. SEM was applied to observe the underlying microstructural changes of CSA/GFRC under different curing regimes. It was found out that there was a gradual degradation of both ultimate tensile strength and ultimate strain of CSA/GFRC with elevated curing temperature and curing age, but glass fibre still shows considerable ability to carry stress alone by bridging cracks. Microstructural studies showed that, at accelerated temperatures of 50°C and 70°C, the space between fibres remained empty in general only with some hydration products adhering to the fibre surface occasionally. At a higher accelerated curing temperature of 80°C, densification of the interfilamentary spaces by larger and clustered hydration products can be observed at longer curing ages, causing the fibres to lose parts of the flexibility. Therefore, it can be concluded that densification of interfilamentary spaces may have a greater role to play in the strength degradation of CSA/GFRC than mechanisms associated with fibre weakening caused by chemical corrosion.

A reduced-order dynamic model, based on three-dimensional (3D) finite element model (FEM) and component modal synthesis technique (CMS), was presented for simulating the dynamic behavior of the spur gear system. The gear shaft and gear body were established via 3D elements to simulate bending and torsion of the gear system. The CMS technique was used to generate a reduced-order model of a spur gear system. A pair of mating teeth was assimilated to two different foundations (one for the pinion tooth and the other one for the gear tooth) linked in series by some independent springs, which was used to simulate the contact stiffness. The validity of the proposed model was verified by static analysis, dynamic analysis, and experimental analysis. The results show that the proposed model is an effective model. In addition, the proposed model has also been applied to analyze spur gear spalling faults. The results show that the dynamic response of the gear system is periodic vibration shock response due to the alternate meshing of single and double teeth. When the spalling fault occurs, some shock responses with significantly enhanced amplitude will be generated as the result of contact loss.

A phenomenological model for single particle erosion (SPE) of plastic materials was constructed based on the Hertzian contact theory and conservation of momentum to solve the particle impact erosion. The extrusion deformation and contact time of materials in three processes of wall elastic extrusion, elastic-plastic extrusion, and elastic recovery were discussed. Later, the critical angle for sliding contact between the particle and metal surface was calculated according to the impact angle of a particle and the corresponding critical sliding friction force of the particle. The wall indentation depths under sliding contact and no sliding contact were compared. Finally, the erosion volume of materials by impact of a single particle was gained. Moreover, a contrastive analysis on calculation results was carried out by using the gas-solid jet erosion experiment. Contact time, normal and tangential deformations of materials, as well as material erosion under sliding contact and no sliding contact in two processes of particle extrusion and rebound were gained from calculation and experiment. The constructed model showed a good agreement without involving too many empirical coefficients.

A swirling burner with a variable inner secondary air (ISA) flaring angle β is proposed and a laboratory scale opposed-firing furnace is built. Temperature distribution and NO_x emission are designedly measured. The combustion characteristics affected by variable β are experimentally evaluated from ignition and burnout data. Meanwhile, NO_x reduction by the variable β is analyzed through emissions measurements. Different inner/outer primary coal-air concentration ratios γ, thermal loads and coal types are considered in this study. Results indicate that β variation provides a new approach to promote ignition and burnout, as well as NO_x emission reduction under conditions of fuel rich/lean combustion and load variation. The recommended β of a swirling burner under different conditions is not always constant. The optimal β_opt of the swirling burner under all conditions for different burning performance are summarized in the form of curves, which could provide reference for exquisite combustion adjustment.

Aiming at obtaining the application characteristics of more nanofluidic stuffing to enrich the database of nanofluidic packer rubber, three zeolite-based nanofluidic types of stuffing with water, glycerin, and a saturated aqueous solution of KCl (hereinafter referred to as saturated KCl solution) as the functional liquids were studied using experiments. The results showed that all the three zeolite-based nanofluidic stuffing types could be applied as stuffing for nanofluidic packer rubber. The setting pressure ranges for zeolite/water, zeolite/glycerin, and zeolite/saturated KCl solution stuffing were 21.71 to 30.62 MPa, 15.31 to 23.57 MPa, and 27.50 to 38.83 MPa, and the specific deformation quantities of the three stuffing types were 72.76, 102.07, and 77.54 mm³∙g⁻¹, respectively. In zeolite/saturated KCl solution stuffing, the number of liquid molecules retained in the nanochannels was the minimum; thus, this stuffing type was the most stable during application. The order of the equivalent surface tensions of the three zeolite-based stuffing types in the confined nanochannels was consistent with the order of the gas–liquid surface tensions in the bulk phase. The equivalent surface tension, which reflected the interaction between liquid–solid phases, dominated the pressure threshold, the deformation capacity, and the stability of nanofluidic stuffing. This research study provided data support for the application of nanofluidic packer rubber.

Gaseous phase plays roles in a liquid/nanoporous system during application that adequate attention should be paid to the gaseous effects and the nanoscale gas-liquid interaction. In the present study, two glycerol/ZSM-5 zeolite systems with different amount of residual gas are compared by performing a series of experiments. Influences of loading rate, as well as system temperature on the gas-liquid interactions, are studied. Results show that vacuum degassing pretreatment is required to obtain a reversible and stable energy absorption system. Moreover, the influence of gas on a liquid/nanoporous system is found to mainly act on the liquid outflow. After the routine vacuum degassing pretreatment, the residual air that is left in the nanopores is around 0.9014 nm^–3 per unit specific pore volume, as presented in the current study. During compression, the existing gas left in the nanochannel tends to gather into the gas cluster, which further promotes the liquid outflow during unloading. However, excessively dissolved gas may reduce the driving force for liquid outflow by breaking the continuity of the liquid molecular chain in nanochannel. Consequently, small bubbles as a labile factor in the system must be excluded for the steady use of the system. This work sheds some light on the effect of the amount of residual gas on the liquid/nanoporous system and gives guidance on the pretreatment of the liquid/nanoporous material mixture before encapsulating.