Publications

Pretreatment before biomass combustion is significant for its efficient utilization and that combined water washing and carbonization can be efficient. An agricultural processing residues sesame stalk was selected and carried out two pretreatments separately, i.e., water washing-torrefaction (W-T) and torrefaction-water washing (T-W), to explore the effect on the fuel properties, combustion characteristics and particulate matter (PM) emission. The obtained biochar was also combusted under air and oxy50 (CO2:O2 = 50:50) conditions for the sake of investigating the effect of pretreatment and combustion atmosphere. The results indicate that, W-T and T-W both not only have great effect on the improvement of fuel properties but also reduce the content of water-soluble elements like K, Cl, etc. Due to the difference in hydrophobicity, the biochar obtained by W-T have the optimal fuel properties. At the same time, the pretreatment also hinder the combustion in a certain extent in which the comprehensive combustion characteristics (SN) show a downward trend. Furthermore, both two pretreatments have obvious benefit on the reduction of PM1 emission and W-T have the best effect related to the higher removal efficiency of inorganic elements (especially K + Na + Cl + S). Under oxy50 condition, the oxygen concentration and combustion temperature is higher, improving the sulfation of K and vaporization of Ca, P and Mg which result in weakening in the pretreatment reduction effect on PM1 emission.

Abstract Vanadium‐based cathodes for aqueous zinc‐ion batteries (AZIBs) face critical challenges in practical capacity and low‐current‐density cycling stability. Herein, a synergistic strategy is introduced that overcomes these limitations through the co‐engineering of an activatable bulk precursor and a dynamic in situ‐formed interface. A porous, V 3+ ‐rich 0.3CaV 2 O 4 ‐0.7V 2 O 3 heterostructure (CaVO‐4) specifically designed to undergo a profound in situ electrochemical activation into highly active phases is first constructed. Concurrently, by leveraging supplemental SO 4 2− in the electrolyte, a stable CaSO 4 ·2H 2 O cathode‐electrolyte interphase (CEI) layer is formed in situ via reaction with Ca 2+ released during cycling. By serving a dual role, the CEI ensures structural durability and simultaneously enables the intrinsic kinetics of the bulk. This “bulk‐to‐interface” synergy manifests in electrochemical performance, including 89.3% capacity retention over 300 cycles at 0.5 A g −1 , an extraordinary rate capability of 424.4 mAh g −1 at 20 A g −1 , and a high specific capacity of 479.2 mAh g −1 at 0.2 A g −1 . Advanced characterizations, including in situ XRD and ex situ XPS/XAFS, combined with DFT calculations, unravel the synergistic mechanisms underpinning the enhanced Zn 2+ storage. This work pioneers a paradigm that unites rational bulk activation with interfacial self‐optimization, providing a strategy for durable, high‐performance cathodes in advanced energy storage.

The devolatilization process has important influence on the formation of PM10 (particulate matter with an aerodynamic diameter of ≤10.0 μm) in oxy-fuel combustion of pulverized coal but has been explored little. A bituminous coal was devolatilized in either CO2 or N2 at 1573 K on a drop-tube furnace (DTF) to produce CO2-char and N2-char. Coal and its char samples were burned at 1573 K and in 29 vol % O2/71 vol % CO2. PM10 was collected and segregated into 13 size fractions, which were subjected to subsequent analysis. The results show that the particle mass size distributions of PM10 from coal and chars have similar peak and trough sizes, suggesting that the devolatilization process has insignificant influence on the major pathways of PM10 formation. Three particle modes can be identified, i.e., ultrafine mode (<0.5 μm, PM0.5), central mode (0.5–2.5 μm, PM0.5–2.5), and coarse mode (2.5–10 μm, PM2.5–10). Coal combustion produces more PM0.5 and PM0.5–2.5 than char combustion, suggesting that the devolatilization process has important influence on the production of PM0.5 and PM0.5–2.5. In contrast, the PM2.5–10 yield is insignificantly affected by the devolatilization process under the investigated conditions. In addition, the combustion of CO2-char generates more PM0.5 and PM0.5–2.5 than that of N2-char, indicating that the devolatilization in CO2 favors the formation of PM0.5 and PM0.5–2.5.

Near-surface mounted (NSM) fiber-reinforced polymer (FRP) technique is known as a promising alternative to the externally bonded (EB) FRP technique for strengthening reinforced concrete (RC) members, on account of its many advantages such as high bond efficiency with concrete and good durability. Shear strengthening of RC beams by near-surface mounting the FRP bars/strips into the concrete cover on beam sides is one of the most prevalent applications of NSM FRP. Abundant experimental studies have been conducted to investigate the behaviour of NSM FRP shear strengthened beams, and many strength models for predicting the contribution of NSM FRPs to the shear capacity of the beam have been proposed. The present paper presents a comprehensive review of these strength models, in which all the models collected from the existing literature are first classified into three categories based on their used approach and then summarized and discussed. This paper not only aims to bring a deep understanding of the existing strength models for NSM FRP shear strengthened RC beams, but also provides a background and basis for the assessment of these models by using the newly-generated experimental database in the companion paper.

The use of fiber-reinforced polymer (FRP) jackets or tubes as confining devices can significantly improve the compressive performance of ultra-high-performance concrete (UHPC). For FRP-confined UHPC, an analysis-oriented stress–strain model is essential for a comprehensive understanding of its compressive behavior and the development of design models. Although several analysis-oriented stress–strain models have been developed for FRP-confined normal-strength concrete (NSC), such models for FRP-confined UHPC are still lacking. In this study, an experiment is conducted to investigate the failure mechanism of UHPC confined with FRP under concentric compression, and the stress–strain behavior of the FRP-confined UHPC is analyzed using the stress–strain models of actively-confined UHPC. Results showed that the stress-path-independency assumption, which has been proven to apply to FRP-confined NSC, was inapplicable to FRP-confined UHPC. By modifying the confining pressure to consider the influence of stress-path dependency, an analysis-oriented model was proposed. The proposed model was verified using a collected test database. The results show that the proposed model accurately predicted the stress–strain behavior of FRP-confined UHPC.