Abstract To explore the resource utilization potential of industrial waste lithium slag (LS) in the ferroaluminate cement (FAC) system, this study conducted tests on the workability, mechanical strength, hydration, and microstructure of LS-FAC composite cement pastes, revealing the influence mechanism of LS on the physical-mechanical properties and hydration process of FAC. The results show that the electrical resistivity at 24 h initially decreased and then increased, whereas the fluidity, setting time, and cumulative exothermic at 72 h decreased with the increase in LS from 0% to 30%. In addition, LS had a promoting effect on the early hydration of the FAC, which could accelerate the hydration exothermic rate, shorten the hydration induction period, and accelerate the hydration process; this effect was due to the active mineral gypsum ( CaSO 4 · 2 H 2 O ) in LS, which could directly participate in the early hydration of FAC and preferentially react with C 4 A 3 S ¯ to form ettringite (AFt), greatly promoting its nucleation and growth. An interesting phenomenon could also be seen: although the incorporation of LS significantly increased the early formation rate and number of AFt, it was hardly helpful for the early strength development of the sample. According to SEM and MIP tests, the addition of LS changed the crystal morphology of AFt. The AFt crystals formed in the early stage were not only short and slender but also mostly disorderly stacked on the surface of cement particles, which cannot be effectively lapped to form a network structure. Although the excessive and rapidly generated AFt filled and refined the large pore size to a certain extent, it led to an increase in porosity and total pore volume and a loose paste structure. This may not be conducive to the development of early strength. However, the compressive strength of mortar samples with 5% and 10% LS at 90 d exceeded that of the control sample, which increased by 6.9% and 3.8%, respectively, mainly because that the volcanic ash activity of LS was sufficiently exerted in the later stage, and an appropriate amount of LS ( ≤ 10 % ) could effectively improve the pore structure of FAC and enhance the later strength. This study demonstrated the feasibility of LS mixed with FAC, which provided a new solution for the high-value utilization of bulk industrial solid waste and the low-carbon development of the building materials industry.
Abstract Understanding the relationship between the built environment and bike-sharing demand is crucial for developing effective transport policies and promoting sustainable urban mobility. Numerous analytical models have been applied to this problem, including generalized linear regression (GLR), spatial econometric models, and machine learning (ML) methods. However, differences in model assumptions and learning mechanisms often yield divergent findings. Relying solely on a single modeling approach therefore risks introducing bias into interpretation and may lead to ineffective policy decisions. Using Shenzhen, China, as a case study, this research investigates the built environmental determinants of bike-sharing demand through negative binomial regression (NBR), geographically weighted regression, random forest, and gradient boosted decision trees. We develop a comprehensive workflow to compare, select, and implement these modeling approaches and to translate model outputs into planning-relevant evidence on the relative importance of environmental factors, the presence of spatial heterogeneity, and the emergence of nonlinear, threshold, or saturation effects. Our results show partial consistency in identifying key environmental factors and general agreement in the direction of associations. GLR and spatial models are particularly useful for early-stage planning and exploratory analysis with limited data, providing clear identification of significant variables and overall directionality. ML models, when supported by larger data sets, reveal nuanced nonlinear patterns and thresholds that are valuable for designing more targeted policy interventions. The study underscores that model selection is not merely a technical choice but a critical decision that shapes the evidence base for bike-sharing planning and built environment interventions.
The development of unfired high-alumina bricks (UHABs) is of great economic and environmental significance, where bonding performance governs mechanical properties and application. A surprising reinforcement of UHABs bonded by merely 6 wt% rectorite via wet milling process was obtained. The effect of wet milling on the slurry rheological behavior, phase composition and microstructure evolution were investigated to understand the reinforcement mechanism. The results indicated that wet milling could promote the exfoliation of rectorite, increase the dispersity and stability of slurry binders. Reducing the solid content of slurry from 35 wt% to 25 wt% achieved a better refinement and exfoliation effect. Exfoliated sheet-like rectorite formed a face-to-face mechanically interlocked network among bauxite particles, while in-situ gismondine (CaAl2Si2O8 & centerdot;4 H2O) formed after heating at 750 degrees C bridged rectorite, increasing cold crushing strength by 67% (similar to 70 MPa). This study aims to provide theoretical assistance for the development of UHABs with satisfied mechanical strength.
Abstract To achieve the synergistic optimization of the performance of ferroaluminate cement–based grouting materials using a borax retarder and calcium nitrite accelerator, this study investigated the effects of different calcium nitrite contents on the physical properties and hydration characteristics at a fixed borax dosage (0.28%) through various testing methods. The testing methods included fluidity, setting time, electrical resistivity, internal temperature, compressive strength, drying shrinkage, X-ray diffractometer (XRD), scanning electron microscope (SEM), and mercury intrusion porosimetry (MIP). The results revealed that calcium nitrite retarded the initial hydration of this system at low contents (0.3% and 0.6%), resulting in a delay in the acceleration period and setting time. Conversely, the hydration was promoted at higher calcium nitrite contents (0.9% and 1.2%), causing an advance in the acceleration period and setting time. The incorporation of calcium nitrite significantly improved the compressive strength from 6 h to 28 days, and reduced the drying shrinkage and mass-loss rates. Microscopic test results showed that calcium nitrite promoted the dissolution of C 4 A 3 S ¯ and the generation of AFt, optimizing the pore structure of the cement pastes. In addition, different calcium nitrite (CN) contents altered the crystal morphology of AFt and contributed to compressive strength by enhancing structural stability and compactness. These results are expected to provide guidance for improving the performance of ferroaluminate cement–based grouting materials by adding calcium nitrite and borax in practical engineering applications.
Bladder cancer intravesical therapy remains limited by rapid urinary washout, insufficient penetration across the bladder mucosal barrier, and an immunosuppressive tumor microenvironment. Here, we developed a bladder microenvironment-adaptive chemo-immunotherapy system, Gel/UCeNZ/Gem/CpG, to improve local bladder cancer treatment. In this system, urease-modified CeO2 nanozymes (UCeNZ), gemcitabine (Gem), and CpG oligodeoxynucleotide (CpG ODN) were incorporated into an injectable thermosensitive adhesive hydrogel. After intravesical administration, the hydrogel rapidly formed a mucosa-adherent depot, thereby prolonging bladder residence and enabling sustained therapeutic release. Meanwhile, UCeNZ responded to endogenous urinary urea to enhance particle transport and mucosal penetration, improving local drug exposure beyond passive instillation. Functionally, CeO2-mediated redox regulation amplified Gem-induced oxidative stress, mitochondrial dysfunction, apoptosis, and immunogenic cell death-associated signaling, as evidenced by HMGB1 translocation/release, calreticulin exposure, and intracellular ATP dysregulation. CpG ODN further promoted dendritic cell maturation and strengthened T cell-mediated antitumor immunity. In an orthotopic bladder cancer model, Gel/UCeNZ/Gem/CpG significantly suppressed tumor progression, prolonged survival, increased CD8+ T cell infiltration, reduced regulatory T cells and M2-like macrophages, and enhanced memory/effector-like T cell activation without obvious systemic toxicity. Transcriptomic analysis further revealed coordinated regulation of oxidative stress, apoptosis, antigen presentation, cytokine signaling, T cell activation, PD-1/PD-L1 checkpoint signaling, and p53-related tumor-suppressive pathways. Overall, this study presents a bladder-adaptive intravesical chemo-immunotherapy strategy that integrates mucosal retention, urea-responsive penetration, redox-amplified immunogenic chemotherapy, and immune microenvironment remodeling for bladder cancer treatment.
