Search Results (6,951)

Supersulfated cement (SSC) is an environmentally friendly cementitious material with a low clinker content, in which industrial byproduct gypsum serves as the sulfate source, thereby enabling the valorization of solid waste. The hydration process, pore structure, microstructure, and hydration products were investigated using paste samples by means of isothermal calorimetry, X-ray diffraction (XRD), thermogravimetric analysis (TG–DTG), Fourier transform–infrared spectroscopy (FT-IR), mercury intrusion porosimetry (MIP), and scanning electron microscopy (SEM), while compressive strength was evaluated using mortar specimens. Compared with ordinary Portland cement (OPC), SSC offers clear advantages in reducing energy consumption and greenhouse gas emissions. In this study, the effects of titanium gypsum (TG) and flue gas desulfurization gypsum (FGD) on the hydration behavior, fluidity, mechanical properties, and microstructural evolution of an anhydrite (AH)–phosphogypsum (PG)-based SSC were systematically investigated. The results indicate that the incorporation of 11% TG and FGD mitigates the strong sulfate environment caused by the rapid dissolution of soluble AH, thereby regulating the hydration process. As the proportion of TG and FGD increased, the cumulative heat release within 72 h gradually decreased. When AH was completely replaced, the cumulative heat release of TG4 and FG4 decreased by approximately 19.7% and 28.6%, respectively. TG and FGD exhibited opposite effects on the fluidity of SSC while both promoting strength development. Among all mixtures, TG2 and FG2 showed the best performance, with the highest 28-day compressive strengths of 50.15 MPa and 51.95 MPa, respectively. Microstructural analysis reveals that differences in particle size distribution and dissolution kinetics among gypsums governed the sulfate release characteristics and slag activation mechanisms, thus leading to distinct hydration pathways, pore structure evolution, and microstructural densification. This study provides a theoretical basis for the efficient utilization of various industrial byproduct gypsums and offers important guidance for the controllable design of SSC performance. Full article

This study quantitatively evaluates the effect of solid-phase pre-reduction of chromite concentrate on the energy efficiency and techno-economic performance of high-carbon ferrochrome (HC FeCr) smelting. Laboratory pre-reduction experiments were conducted at 1200–1400 °C using Shubarkol coal, metallurgical coke, and special coke as carbonaceous reducing agents. Structural and phase transformations were characterized by X-ray diffraction (XRD) and scanning electron microscopy with energy-dispersive spectroscopy (SEM-EDS). At 1200 °C, the degree of metallization remained low (<5%), whereas at 1400 °C it increased to 41.3% under laboratory conditions and up to 65% in pilot-scale tests due to the decomposition of the spinel matrix and the formation of metallic and carbide phases. The application of pre-reduced feedstock in a submerged arc furnace reduced specific electricity consumption by up to 33.5% compared with conventional smelting and increased chromium recovery to 89.71%. Industrial-scale extrapolation indicates the potential to decrease power consumption to approximately 3190 kWh/t of alloy. Techno-economic analysis demonstrates that the use of pre-reduced feedstock reduces the production cost by approximately 10–23%, depending on the type of carbonaceous reducing agent (Shubarkol coal, metallurgical coke, or special coke). Special coke provided the highest energy efficiency, whereas Shubarkol coal ensured the greatest direct economic benefit. The integrated microstructural, energetic, and economic assessment confirms the industrial applicability of the proposed pre-reduction approach. Full article

Hydrogen plasma heating, a unique method for heating and reducing iron ore, is distinguished by its high heat, rapid reduction, and high efficiency, making it a promising technique in the metallurgy field. In this study, a non-transferred arc plasma heating system was used with Ar-H₂ as the working gas and acidic pellets as the raw material. The microstructures and elemental distributions of the slag and iron phases during the reduction process were examined using electron microscopy and energy-dispersive X-ray. The variation patterns of Fe-containing phases in the reduction products were found using X-ray diffraction and full-spectrum fitting refinement. The conversion rate of the oxidized pellets and the deoxidation conversion rate per area were estimated for various gas flow rates and reduction times. A reaction kinetics model was also used to study the reaction controlling step. The results showed that during the reduction process, with an H₂ flow rate of 4.5 L min⁻¹ and a 40 min reduction, the conversion(α) reached 99.89% and the purity of the reduced metallic iron reached 99.9%, achieving the industrial-grade 3N standard. Si and Al in the melt bath generated fayalite (Fe₂SiO₄) and hercynite (FeAl₂O₄) with Fe_xO. The deoxidation conversion rate per unit area was 1.11 g (cm² min)⁻¹. A three-dimensional diffusion-controlled model was used to describe the reduction process, and the mechanism function was 2/3(1 + α)^3/2[(1 + α)^1/3]⁻¹. The values of the reduction reaction rate constant (K) were 12.6 × 10⁻² s⁻¹ and 12.8 × 10⁻² s⁻¹ when the flow rates of H₂ gas were 3 and 4.5 L min⁻¹, respectively. The apparent activation energy was 21.9 kJ mol⁻¹. The empirical equation for the specific reduction rate was calculated as ln r = −2637.5/T − 0.407. Full article

Additively manufactured stainless steels are gaining considerable attention in the production of complex components, especially in the aerospace, food production, energy, and biomedical industries. Machining and achieving the desired surface properties of such materials remains a challenge. Abrasive waterjet machining technology appears to be one of the options due to the advantages it brings. Removing support structures and separating individual parts is also one of the possible applications of this technology. This study investigates the effects of process parameters for individual cut qualities (Q1–Q5) of abrasive waterjet on the surface properties of additively manufactured stainless steel (SS 316L) specimens, considering the different mechanical properties of the material due to the direction of layering of the material during its production. Experimental specimens were prepared by selective laser melting technology with parameters ensuring the best possible quality of the resulting part. The results of the study showed changes in the topography of the machined surface, especially in the roughness parameters. Scanning Electron Microscopy and Energy Dispersive X-ray Spectroscopy analysis proved the presence of fragmented abrasive particles in the cut areas. Full article

The present work aims to investigate the microstructure and mechanical properties of laser beam spot welds in the superalloy Nimonic 80 A. Considering the importance of this innovative process in the manufacturing of engineering components for high-security industries, it is necessary to study the influence of the welding thermal cycle on the microstructure and mechanical properties of welded joints. The rapid heating/cooling, melting, and re-solidification phenomena that occur during welding modify the metallurgical characteristics of the weld compared with the microstructure of the base metal. Because the energy density is high and the process duration is very short, the microstructure obtained after solidification is fine dendritic in the central area of the joint and columnar in the weld–base metal transition zone. For the same reasons, the heat-affected zone (HAZ) is slightly extended. The increase in the size of the crystalline grains in the HAZ is negligible due to the low diffusivity of the nickel-based γ solid solution matrix, which inhibits the rapid migration of grain boundaries during the welding process. Metallographic analyses were performed using optical microscopy and scanning electron microscopy. The microhardness values, 152–168 HV0.05 in the weld and 180–190 HV0.05 in the base metal, together with the tensile–shear strength values (760–780 N/mm²) obtained at room temperature, demonstrate that the proposed welding process is appropriate and feasible for engineering applications involving Nimonic 80A superalloys. Full article

The yellow peach moth, Conogethes punctiferalis, is a destructive polyphagous pest and poses a severe threat to the fruit industry and field crops worldwide with its continuously increasing population and expanding host range in recent years. Despite the severe damage caused by C. punctiferalis larvae, their antennae and mouthparts, equipped with abundant sensilla responsible for feeding behavior, have not been investigated in detail. In our study, the antennae, mouthparts, and associated sensilla of first-instar and mature larvae of C. punctiferalis were examined with light and scanning electron microscopy. Our results revealed no obvious morphological differences between the two instars in the basic composition of the antennae and mouthparts, or in the types, distribution, and numbers of sensilla. The antenna is three-segmented, with no sensilla on the scape, three sensilla basiconica and two sensilla chaetica on the pedicel, and three sensilla basiconica and one sensillum styloconicum on the flagellum. The mouthparts of C. punctiferalis are typically mandibulate and consist of a labrum-epipharynx, paired mandibles, a pair of maxillae, a labium, and a hypopharynx. Six types of sensilla were primarily concentrated on the labrum-epipharynx, maxilla, and labial palp, including sensilla chaetica, sensilla basiconica, sensilla styloconica, sensilla digitiformia, sensilla epipharyngea, and sensilla placodea. We conducted a systematic analysis of the characteristics of sensilla and discussed their variation in the context of Lepidoptera phylogeny. The potential functions of the sensilla have also been inferred. The study could advance our understanding of the behavioral ecology of C. punctiferalis and provide potentially useful information on the development of pest control technologies. Full article

Photocatalytic CO₂ reduction to high-value-added C₂+ products is a practical route from an economic viewpoint for advancing the industrialization of CO₂ conversion. Despite significant progress in catalyst modification in recent years (such as defect engineering, heterostructure construction, and single-atom modification), the generation of C₂+ products still faces challenges due to the slow kinetics of multi-electron reactions and the high thermodynamic barrier for C-C coupling. Moreover, the severely imbalanced molar ratio of CO₂ to H₂O in the traditional liquid-phase reaction systems exacerbated the challenge to the unfavorable situation. This article summarizes various strategies to improve the yield of C₂+ products through the regulation of reaction environments, including: (1) increasing the partial pressure of CO₂ to enhance its solubility; (2) using alternative solvents like ionic liquids to reduce water content; (3) transitioning the reaction system from liquid phase to gas phase; (4) designing a three-phase (gas–liquid–solid) interface or floating photocatalysts to optimize reactant transfer and local concentration; (5) utilizing photothermal synergistic effects to enhance the reaction temperature and efficiency under concentrated light. It also discusses the role of different reactor designs in improving the reaction environment. Finally, it emphasizes that future research should pay more attention to the optimization of the reaction environment engineering in addition to catalyst design, providing new perspectives for achieving efficient and highly selective C₂+ products in CO₂ photoreduction. Full article

To promote the high-value utilization of fly ash (FA) and address the prolonged setting time and limited strength associated with conventional single-alkali activation, this study proposes a synergistic dual-alkali activation strategy using Ca(OH)₂ and Na₂SiO₃ in combination with microwave-assisted curing for low-calcium fly ash. Samples containing varying amounts of Ca(OH)₂ were systematically characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), compressive strength testing, and pore structure analysis. The results show that Ca(OH)₂ facilitates the formation of calcium aluminosilicate hydrate (C-A-S-H) gel, while Na₂SiO₃ sustains the alkaline environment and enhances the dissolution of SiO₂ and Al₂O₃ from FA. The dual-alkali synergistic system, when coupled with microwave treatment, markedly refines the pore structure, increases the degree of polymerization, and improves compressive strength from 0.5 MPa to 1.7 MPa with increasing Ca(OH)₂ content. In addition, the prepared fly ash-based geopolymer (FABG) demonstrates pronounced pH-buffering capacity in acidic environments and exhibits antibacterial activity, primarily attributable to its sustained release of alkalinity. This work highlights that integrating dual-alkali activation with microwave curing can simultaneously enhance microstructural development, chemical stability, and functional performance in low-calcium FA systems, thereby offering a viable route for the development of sustainable and multifunctional green building materials derived from industrial solid waste. Full article

Effluents from industries, manufacturing companies, textile looms, and floodwater contaminate the surface water reservoirs. This endangers the quality of water for use by humans. Wastewater remediation is one of the ways to recycle the dirty water and make it suitable for use. Photocatalysis is the most common method for wastewater remediation, especially using Titanium dioxide (TiO₂) nanoparticles. However, chemical synthesis and direct addition of nanoparticles may cause toxicity to the flora and fauna present in the water body. To address this limitation, we have green-synthesized TiO₂ nanoparticles using a horticulture waste, Calendula officinalis dried flower extract and entrapped them in a natural polymer, chitosan (CTS-TiO₂-CO nanocomposite). The polymer entrapment ensures biocompatibility as well as reduced aggregation of nanoparticles. The synthesized CTS-TiO₂-CO nanocomposite was characterized using UV-visible spectrophotometry, dynamic light scattering, zeta potential, Fourier Transformed Infrared Spectroscopy (FTIR), X-ray diffractometry (XRD), scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDAX) analysis. The absorption peak was found at 302 nm, and the hydrodynamic diameter at 490 nm. SEM images show flower-like morphology with 326 nm average particle diameter. The non-toxic dose of the nanoparticles was estimated by MTT assay and zebrafish embryo developmental studies. More than 82% fibroblast cells were viable after treatment with 100 μg/mL of CTS-TiO₂-CO nanocomposite. 85% embryos hatched after treatment with 50 μg/mL of CTS-TiO₂-CO nanocomposite. Further, the textile dye remediation assessment was done using the dye crystal violet, exhibiting 69.19% dye degradation after 4 h of sunlight exposure. Altogether, the results demonstrate that the CTS-TiO₂-CO nanocomposite was effective in the remediation of crystal violet without causing any toxicity up to a dose of 100 μg/mL. Full article

This study investigates the hydrophobic properties of hexamethyldisiloxane (HMDSO)-based coatings deposited by atmospheric pressure plasma-enhanced chemical vapor deposition (AP-PECVD). The objective of this procedure is to enable the extraction of molded components from the mold cavity. The test specimen geometry employed in the present investigation were made of tool steel 1.2311, a material that is frequently utilized in industrial applications. A series of experiments was conducted to assess the coating performance. Initially, surface energy measurements based on contact angle analysis were performed to determine the polar and dispersive surface components. Finally, energy-dispersive X-ray spectroscopy (EDX) and scanning electron microscope (SEM) images are used to perform an exact measurement of the elemental composition and an optical comparison of the surface. The results of the work indicate that the material composition on the surface of silicon and oxygen is of particular importance. In addition, the results indicate that the use of argon as a carrier gas has a positive effect on reducing surface energy and increasing the contact angle to water drops. Full article

Autotrophic denitrification using sulfur compounds is considered an alternative to heterotrophic denitrification for the treatment of organic carbon-deficient wastewaters. However, the stoichiometric characteristics of denitrification using different sulfur species, particularly thiocyanate (SCN⁻) and sulfite (SO₃²⁻), remain poorly understood. Here, partial autotrophic denitrification driven by thiocyanate or sulfite was studied in two batch reactors. The stoichiometry of thiocyanate-oxidizing denitrification was assessed based on valence and ultimate product analysis. No nitrate removal was observed in the sulfite-fed system, indicating that sulfite could not serve as an effective electron donor for autotrophic denitrification under the tested conditions. In contrast, simultaneous removal of SCN⁻ and NO₃⁻ was achieved in the thiocyanate-fed system, with removal efficiencies of 100% and 92.5 ± 3.6%, respectively. After 36 h, total nitrogen removal reached 63.3%, with nitrite identified as the dominant intermediate product (26.7%). NO₂⁻ and NH₄⁺ accumulated during the process could be further removed through anaerobic ammonium oxidation. Thiocyanate sulfur was primarily oxidized to sulfate via elemental sulfur as a transient intermediate. These findings provide a theoretical basis for applying thiocyanate-driven partial autotrophic denitrification to nitrogen removal from industrial wastewaters, particularly those generated via coal gasification and cyanide-utilizing gold mining processes. Full article

To address the high-salinity and hyper-humid thermal environment of tropical oceans and meet industrial demands for high strength and lightweight, austenitic low-density steel was developed as a novel corrosion-resistant steel. A 3.5 wt.% NaCl solution was used to simulate the marine environment to study the effect of Si on the corrosion behavior of this steel. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and electron probe microanalysis (EPMA) were employed to characterize the microstructures and corrosion behaviors of two test steels, as well as the phase compositions and element distributions of corrosion products after polarization and cyclic immersion accelerated corrosion tests. The results show that a dense oxide film initially forms on the steel surface in 3.5 wt.% NaCl solution at the early corrosion stage. Si addition induces SiO₂ formation and promotes Al conversion to Al₂O₃, enhancing oxide film compactness and inhibiting matrix atom outward diffusion and Cl⁻ inward penetration. With prolonged corrosion, the oxide film is dissolved or broken, forming a dense rust layer dominated by Fe₃O₄, Fe₂O₃ and FeOOH. Si enriches in the inner rust layer adjacent to the matrix and pitting cavities, inhibiting pitting deepening and promoting γ-FeOOH to α-FeOOH transformation, thus improving the steel’s corrosion resistance. Full article

As wearable electronic products have been integrated into daily life, flexible pressure sensors, which convert pressure into electrical signals, have become a research focus because of their cross-industry application potential. Despite an increasing number of related studies, the systematic integration of discussions on sensing mechanisms, performance regulation, and multiscenario adaptability remains to be explored. In this paper, core sensing mechanisms such as piezoresistive, capacitive, piezoelectric, and triboelectric mechanisms are systematically reviewed; key performance indicators, including sensitivity, response time, and linearity, are analyzed; construction strategies for diverse substrates and conductive functional materials are explored; and applications in healthcare, human–computer interaction, and electronic skin are elaborated on. The aim of these analyses is to provide practical insights into the development and design of flexible pressure sensors, thus providing a useful reference for advancing these technologies and expanding their cross-domain use. Full article

This study examines the carbonation behavior and CO₂ storage potential of a Ca-rich alkali-activated binder produced entirely from industrial residues-ladle furnace slag (LFS), coal ash (CA), and cement kiln dust (CKD). The system was designed as a one-part alkali-activated material (AAM), with CKD acting as an internal activator, and subjected to ambient curing, water curing, and accelerated CO₂ curing at ambient pressure. Phase evolution, microstructural development, and pore-structure characteristics were investigated using X-ray diffraction, FTIR spectroscopy, DSC–TG analysis, scanning electron microscopy, and X-ray micro-computed tomography, together with measurements of density, water absorption, and compressive strength. Loss-on-ignition measurements combined with chemical analysis were further used to quantify CO₂ uptake and evaluate the degree of carbonation of the binder system. CO₂ curing fundamentally altered the reaction pathway of the binder, shifting it from hydration-dominated to carbonation-controlled phase evolution, leading to the decomposition of calcium-bearing hydrates and complete carbonation of non-hydraulic γ-belite with the formation of vaterite, aragonite, and calcite. These transformations induced pronounced microstructural densification, reflected in a near-doubling of compressive strength (>48 MPa), increased apparent density, reduced water absorption, and simplified pore-network topology. A preliminary carbon footprint assessment indicates that the production of 1 m³ of the developed LFS–CA–CKD concrete generates about 14.36 kg CO₂-eq, while the carbonation process enables significant CO₂ sequestration, resulting in a net negative carbon balance. The results demonstrate that controlled carbonation is an effective post-treatment strategy for waste-derived alkali-activated binders, enabling simultaneous performance enhancement and permanent CO₂ sequestration. Full article

Textile materials represent a versatile class of engineering substrates widely used in apparel, domestic products, and medical protective systems. Despite their extensive application, large-scale textile production has seen limited integration of fundamentally new functionalization strategies. In recent years, however, advances in materials science have enabled the development of textiles with tailored electrical, adaptive, and biological functionalities. This review summarizes recent progress in the functionalization of textile materials with a focus on approaches relevant to engineering and industrial implementation. Particular attention is given to conductive textiles designed for operation under extreme environmental conditions, including low-temperature climates. Methods for integrating electrically conductive elements into fibrous structures are discussed, highlighting their potential for sensing, thermal regulation, and energy-related applications such as powering portable electronic devices. Inkjet printing is presented as a scalable technique for high-resolution deposition of conductive patterns while preserving the mechanical integrity and aesthetic properties of textile substrates. In addition, adaptive and stimuli-responsive textile systems are reviewed, including materials capable of responding to thermal, optical, or chemical stimuli, with applications in camouflage, wearable systems, and multifunctional surfaces. The review further addresses the development of bioactive textiles, emphasizing antibacterial functionalization using organic and inorganic agents to mitigate the spread of pathogenic microorganisms. The relevance of such materials has been underscored by recent global viral outbreaks. Overall, this work aims to provide a materials science perspective on emerging textile functionalization strategies and to facilitate the transition of these technologies from laboratory-scale research to practical engineering applications. Full article