Retrofits for ultra-low emissions couple residual energy recovery with pollution control because treatment units alter flue gas states and downstream recovery pathways. This study develops an exergy–cost optimization framework that jointly configures flue gas treatment, by-product gas conversion, multi-grade waste heat recovery, terminal energy services, and in-plant transport. Mechanism-constrained grey-box modules propagate stream states through reconfigurable treatment chains, and NSGA-II searches Pareto solutions under emission, operating-window, acid-dew-point safeguard, sulfur-tolerance, capacity, and topology constraints. For the synthetic reference steelworks, recoverable source exergy was 341.13 MW, 72.2% of which originated from by-product gases. The balanced solution selected an ESP–WFGD–reheater–WHPG–SCR route, with 238.06 MW augmented system exergy loss, a 30.21% recoverable source exergy utilization index, a 6.29% unused-source ratio, and a net system cost of − 57.63 × 103 CNY/h. Across twelve scenarios, pollutant loading altered treatment-chain selection, gas availability strongly affected power generation and economic response, and seasonal demand redistributed low-grade heat. Removing the unused source opportunity term increased unused recoverable exergy by 67.97 MW. Under high NOx loading, 10% tighter pollutant set points removed the WHPG branch with only a 0.038% increase in augmented loss. Plant application requires site-specific recalibration and independent validation.
We investigate phonon localization in one-dimensional quasiperiodic dimerized chains, by considering the presence of Aubry-André-Harper (AAH) disorder on the spring mass. It shows that in this system, three phases come into being, i.e., the extended, mixed, and localized phases, respectively, during the localization process. Furthermore, such a disorder promotes several bulk states to transform into edge states before the occurrence of global localization. For a floating chain, this phenomenon mainly exists in the optical branch, with the edge states localized at one end of the chain. Instead, if each site is grounded with a spring, such edge states can be observed in the acoustic and optical branches, with their localization directions being opposite. Regarding the topological states, their degenerate energy splits into two with the enhancement of disorder, and the resultant two states also show the opposite localization directions. We believe that the findings in this work provide a new understanding of the phonon localization in one-dimensional dimerized chains.
The ZGH452 alloy possesses outstanding high-temperature strength, corrosion resistance, and fatigue durability, offering strong potential for aerospace and energy applications. However, its high crack sensitivity limits widespread use. To address this issue, the present work examines the effects of annealing temperature from 500 to 1300 degrees C on the microstructural evolution and residual stress relaxation of the alloy fabricated by selective laser melting. The results reveal that no gamma ' precipitates form below 800 degrees C, while fine coherent gamma ' particles with an average size of about 115 nm emerge at 900 degrees C and coarsen to approximately 300 nm at 1000 degrees C, where crack density reaches its maximum. Further heating promotes gamma ' coarsening, partial dissolution, and reprecipitation, producing a uniform equiaxed morphology of around 198 nm and pronounced crack healing at 1300 degrees C. Residual stresses decrease sharply with increasing temperature and nearly vanish above 1200 degrees C due to diffusion- and recrystallization-assisted relaxation. Electron backscatter diffraction analysis confirms a transition from partial recrystallization of about 25 % to nearly complete recrystallization of approximately 90 % between 1100 and 1300 degrees C. The hardness evolution follows three distinct regimes: stress-relaxation softening, gamma '-strengthening, and recrystallization recovery. These findings provide important references for optimizing post-annealing treatments and enhancing the structural integrity of selective laser melted ZGH452 alloy.
Given the pressing global energy crisis, developing high-performance, stable electrocatalysts for hydrogen production through water electrolysis is of paramount significance. In this work, a nickel-cobalt (Ni-Co) precursor is first synthesized on a nickel foam (NF) substrate via a hydrothermal approach, the layered structure of the precursor enables the atomic-scale dispersion of Co2+ and Ni2+ ions, ensuring that the two metal elements are uniformly distributed in the selenide at a 1:1 ratio after subsequent selenization. Additionally, it can act as a template to guide the selenization and composite reactions, allowing the final product to retain a certain layered derived structure. followed by the in-situ growth of a Co0.5Ni0.5Se2@NiFe-LDH(Nickel-Iron Layered Double Hydroxide) heterostructured catalyst on its surface. Electrochemical tests in a 1 M KOH electrolyte reveal that the as-prepared catalyst exhibits exceptional hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) activities: at a current density of 50 mA cm(-2), the required overpotentials are merely 219 mV and 247 mV, respectively. More notably, when tested in an alkaline seawater electrolysis system-an environment closer to practical application scenarios-the catalyst retains its high catalytic efficiency, with the HER and OER over-potentials increasing only slightly to 223 mV and 249 mV (at 50 mA cm(-2)). These results underscore the catalyst's promising potential for real-world applications and provide a novel strategy for the design of high-efficiency bifunctional electrocatalysts for water electrolysis.
Aqueous calcium-ion batteries (ACIBs) are a prospective solution for electrochemical energy storage. The scarcity of cathode materials with high capacity and long cycling lifespan making CIBs' development still in infancy. Vanadium-based compounds have long been considered promising cathode materials due to their low cost, abundance and high theoretical capacity. However, the low conductivity of vanadium-based materials and the lattice volume expansion during charging and discharging processes have been limiting their development and potential applications. Herein, to tackle these fundamental challenges, we designed and synthesized core-shell calcium vanadate cathode nanoparticles that feature rich oxygen defects and carbon encapsulation (denoted as d-CaV2O5-X@C). Compared with the pure phase vanadium trioxide without calcium ions, calcium vanadate materials incorporating calcium ions exhibit enriched defect structures that provide additional active sites, thereby enhancing the reaction kinetics. The further carbon encapsulation protects of structural integrity and increases conductivity. The d-CaV2O5-X@C cathode material exhibits a high specific capacity of 188.4 mAh center dot g- 1 at a current density of 200 mA center dot g- 1 and long cycle stability with 96.6 mAh center dot g- 1 retention after 4500 cycles at a current density of 5000 mA center dot g- 1 for aqueous calcium ion storage. This work provides a novel design approach for the advancement of cathode materials for advanced CIBs.
