Materials

Cu₂O nanoparticles (0–4 g/L) were incorporated into the electrolyte to fabricate coatings on TA2 pure titanium via micro-arc oxidation. The effects of different Cu₂O nanoparticle concentrations on the microstructure, antibacterial performance, formation, and antibacterial mechanisms of the coatings were investigated. Microstructural characterization indicated that Cu₂O nanoparticles were incorporated into the coating through the combined action of electrophoretic forces and micro-discharges. At 4 g/L Cu₂O, the incorporation of Cu₂O nanoparticles shifted from uniform incorporation to particle aggregation. Compared with coatings fabricated using 1 and 2 g/L Cu₂O nanoparticles, those fabricated using 3 and 4 g/L exhibited superior antibacterial efficacy. Copper ion release was the primary antibacterial mechanism. Micro-arc oxidation coatings modified with 3 g/L Cu₂O nanoparticles achieved the best compromise between microstructural uniformity and antibacterial performance among the tested concentrations.

Preliminary selection of bracing systems in high-rise steel buildings requires comparing many configurations, each demanding computationally intensive minimum-weight design. This study uses machine learning to estimate the best-observed feasible weight directly from building-level configuration parameters. A full factorial dataset of 45 configurations covered three storey numbers (17, 24, and 30), three bracing types (V, X, and K), and five brace-placement layouts. Each configuration was optimized in a coupled SAP2000–MATLAB procedure with Particle Swarm, Grey Wolf, Honey Badger, and Aquila optimization (180 runs in total); no single algorithm was best for every configuration. Mean weight increased from 2537 kN at 17 storeys to 7103 kN at 30 storeys. X-bracing gave the highest mean weight at all heights and K-bracing the lowest at 17 and 24 storeys, whereas V- and K-bracing differed by only 2.4% at 30 storeys. Bracing type changed the mean weight by up to about 30%, and brace placement by about 10–15%. Among six regression models, Ridge achieved the highest mean five-fold cross-validated R² (0.914; 0.904 over 1000 repeated partitions), while Random Forest gave the lowest RMSE (511.7 kN); in leave-one-out prediction, Ridge ordered 90.3% of configuration pairs correctly. The resulting Ridge equation offers an interpretable screening tool within the investigated design domain.

The cement and concrete industry now has access to a wider variety of cementitious material options than at any point in its history, yet only a subset of these materials are deployed at scale. Current construction practices are evolving from traditional cements towards Portland limestone cements and blended systems such as Limestone Calcined Clays (LC³), alongside expanded use of established and emerging supplementary cementitious materials (SCMs) and alternative SCMs (ASCMs). Industrial by-products, including changing fly ash and slag streams, electric arc furnace slag, reclaimed ash, waste glass, mine tailings, and recycled concrete fines for enhanced carbonation are emerging as feedstock options to supplement demand for SCMs. This review provides a materials-centric synthesis of cementitious material options that could contribute to the U.S. cement and concrete supply through approximately 2035–2040. The materials are organized into two broad readiness classes: readily available materials and blended systems with existing feedstock streams and credible near-term adoption pathways, and emerging material concepts for which processing, logistics, or qualification frameworks are not yet sufficiently mature for industry-wide deployment. Readily available options include calcined clays, limestone calcined clay cement (LC³) systems, ground lightweight aggregate fines, and reclaimed ash, while emerging options include mine tailings, recycled concrete fines, electric arc furnace slag, waste glass pozzolans, carbonation-cured binders, and biocementation approaches. For each material family, the review evaluates availability, technical performance, and standards and adoption status, including feedstock volumes and geographic distribution, processing requirements, reported strength and durability performance, and compatibility with existing production and construction practices. Across both readiness classes, broader deployment will require robust reactivity and performance test methods, long-term durability and field-performance evidence, supply-chain readiness, and staged qualification and specification pathways. The review concludes by identifying practical priorities for researchers, standards bodies, and major buyers seeking to advance next-generation cementitious materials from laboratory evaluation and demonstration toward routine use.