Search Results (38,042)

Reducing the carbon footprint of cement based materials requires approaches beyond replacing cement alone. Mineral carbonation of aggregates offers a simple route to store carbon dioxide permanently while improving material performance. In this study, four steel slag aggregates were evaluated as sand replacements in mortar after pre carbonation, including basic oxygen furnace slag, blast furnace slag, skim slag, and Rockport slag. The aggregates were treated using moisture assisted carbonation with carbon dioxide and then used in mortar made under the same mix design and curing conditions. Bulk chemistry was determined by X-ray fluorescence, carbon uptake was quantified by thermogravimetric analysis, and performance was evaluated using compressive strength, ultrasonic pulse velocity, chemical soundness, freeze thaw resistance, and scanning electron microscopy. Pre-carbonation stored approximately 14–19 wt% CO₂ relative to the dry mass of the slag aggregates, depending on slag type. Mortars with carbonated basic oxygen furnace slag and carbonated blast furnace slag showed clear strength gains at 28 days, along with higher ultrasonic pulse velocity and improved chemical durability. Rockport slag showed modest improvement, while skim slag showed a reduction in strength after carbonation. Microstructural observations indicate that carbonate precipitation filled pores and densified the aggregate paste interface, which explains the strength and durability improvements in the more responsive slags. These laboratory-scale results show that, under the specific moisture-assisted pre-carbonation conditions investigated, pre-carbonation of slag aggregates can combine permanent CO₂ storage with improved mortar performance. However, the magnitude of these benefits depends strongly on slag chemistry and particle structure, highlighting the need for slag-specific carbonation design and further validation under practical conditions. Full article

In this study, shale samples with diverse lithofacies from the Lower Silurian Longmaxi Formation in the Fuling Field were investigated to evaluate the variations in pore characteristics and methane adsorption capacity (MAC) of different shale lithofacies. A set of experiments were performed, such as total organic carbon (TOC) content, X-ray diffraction (XRD), field emission–scanning electron microscopy (FE-SEM), low-pressure gas (CO₂/N₂) adsorption, and high-pressure methane adsorption. Combined with TOC content and mineral composition, three types of shale lithofacies were identified, including organic-rich (OR) argillaceous-rich siliceous (S-3) shale lithofacies, organic-moderate (OM) argillaceous/siliceous mixed (M-2) shale lithofacies, and organic-lean (OL) siliceous-rich argillaceous (CM-1) shale lithofacies. Through detailed comparative analyses, we found that OR S-3 shales possess the maximum TOC content, the most developed heterogeneous organic micro-mesopores, the largest pore volume (PV), and the highest pore surface area (PSA); consequently, they display the strongest MAC. Conversely, OL CM-1 shales have the lowest TOC content and the highest clay content, and thus the smallest PSA and the poorest methane adsorption performance. In conclusion, considering the excellent gas storage potential, sustained shale gas production, and brittle response to hydraulic fracturing, OR S-3 shales are superior to shale gas exploration and exploitation compared with OM M-2 and OL CM-1 shales. Full article

Background/Objectives: Primary ciliary dyskinesia (PCD) is a rare inherited disorder caused by dysfunction of motile cilia, leading to chronic respiratory disease. Diagnosis is challenging due to heterogeneous and non-specific clinical manifestations and the absence of a single definitive diagnostic test. Current diagnostic strategies rely on a combination of functional, ultrastructural, and genetic analyses. The objective of this study was to evaluate whether ciliary beat frequency (CBF), combined with ciliary beat pattern (CBP) assessment using digital high-speed video microscopy (DHSV), could serve as an effective first-line screening tool to identify patients requiring further diagnostic investigations. Methods: This single-center retrospective study included 65 patients (52 children and 13 adults) with clinical suspicion of PCD. Ciliary beat analysis was performed on nasal or bronchial samples using DHSV and Sisson–Ammons Video Analysis software. CBF and CBP were assessed and compared between patients with confirmed PCD and those in whom PCD was excluded based on transmission electron microscopy (TEM) and/or molecular genetic analysis. Results: Fifteen patients were diagnosed with PCD. Mean CBF was significantly lower in the PCD group compared with the non-PCD group (3.3 Hz vs. 8.1 Hz; p < 0.001). A CBF cut-off value of 5.25 Hz yielded a sensitivity of 78.6% and a specificity of 95.7%. Three patients with PCD had CBF values above this threshold; however, two of them exhibited abnormal CBP. Sample type, patient age, and the presence of airway pathogens did not significantly influence CBF measurements. Conclusions: CBF and CBP analysis using DHSV represents a useful first-line screening tool within a multifaceted diagnostic approach for PCD, allowing rapid identification of patients who should undergo further confirmatory testing. Full article

Poliovirus (PV), a historically significant enterovirus responsible for severe paralytic diseases, has seen its incidence dramatically reduced through widespread vaccination efforts, propelling global eradication initiatives. Despite the success of traditional oral poliovirus vaccines (OPVs) and inactivated poliovirus vaccines (IPVs), challenges such as vaccine-derived virus reversion and biosafety concerns during vaccine production persist. Virus-like particle (VLP) vaccines, which mimic native viral structures without containing viral genomes, offer enhanced safety profiles and robust immunogenicity, positioning them as promising candidates for next-generation poliovirus vaccines, especially in the post-certification era. This review systematically summarizes current progress in poliovirus VLP vaccine research, including the diverse expression systems employed for VLP production, strategies for peptide assembly and stabilization, and evaluations of antigenicity and immunogenicity. Additionally, it highlights structural analyses utilizing cutting-edge cryo-electron microscopy. By integrating recent developments in genetic engineering, structural biology, and immunology, this article discusses the advantages and challenges associated with poliovirus VLP vaccines and explores future directions aimed at supporting the global goal of a poliovirus-free world. This comprehensive overview aims to provide a theoretical foundation and technical guidance to facilitate the development and deployment of safer and more effective poliovirus vaccines. Full article

This study investigates the gel characteristics of alkali-activated materials (AAMs) synthesized using wood ash (WA), and metakaolin (MK) as solid precursors. The research explores the influence of precursor type and sodium hydroxide (NaOH) concentrations in the alkali activator solution on the resulting physicochemical, microstructural, mechanical, and radiological properties of gels. The alkaline activators were prepared by mixing sodium hydroxide solutions (6 M and 12 M) with a sodium silicate (water glass) solution at a volume ratio of 1.5. The physicochemical characteristics of raw materials and AAMs were thoroughly analyzed using X-ray fluorescence (XRF), Diffuse Reflectance Infrared Fourier Transform (DRIFT) spectroscopy, X-ray diffraction (XRD), and scanning electron microscopy (SEM) with EDS elemental mapping. FTIR analysis confirmed the formation of an amorphous gels geopolymer network. XRD revealed the presence of characteristic crystalline phases (quartz, calcite) within an amorphous matrix. Mechanical properties, such as compressive strength, depended on precursor type and alkali molarity: metakaolin (12 M) reached ~14 MPa, while wood ash showed ~4 MPa (6 M) and ~0.5 MPa (12 M) due to high CaO, low Si and Al, and unfavorable SiO₂/Al₂O₃ (5.71) and Na₂O/Al₂O₃ (3.19) ratios. Furthermore, this research estimates radiological doses by quantifying radionuclide content via gamma-spectrometry. Alkali activation significantly reduced radiological hazard parameters, with radium equivalent activity (Ra_eq) decreasing to 238.0 Bq/kg and the external hazard index (H_ex) to 0.643 for A₁₂MK, while the annual effective dose rate for A₁₂WA was only 0.265 nSv/y-all values remaining well below the recommended safety limit of 370 Bq/kg (≤1 mSv/y). The decrease in activity concentration index (I_γ), Ra_eq, and H_ex with increasing NaOH concentration indicates effective radionuclide immobilization within the geopolymer matrix, confirming the suitability of these alkali-activated materials for safe use in construction from a radiation protection perspective. Full article

The growing demand for higher-energy lithium-ion batteries, encompassing consumer electronics, stationary grid storage, and electric mobility to specialized sectors like aerospace, medical devices, and industrial robotics, requires cathode materials that offer higher capacity while remaining cost-effective. This trend has intensified the development of nickel-rich LiNi_1−x−yMn_xCo_yO₂ (NMC) systems. However, high-Ni NMCs such as LiNi_0.9Mn_0.05Co_0.05O₂ (NMC90) suffer from limited thermal and cycling stability. Core–shell architectures using LiNi_0.6Mn_0.2Co_0.2O₂ (NMC622) as a shell can partially alleviate these drawbacks, but structural degradation caused by interdiffusion between the core and shell persists as a major challenge. This study investigates whether a tungsten oxide interlayer can act as a protective barrier that suppresses interdiffusion, stabilizes the crystal structure, and improves long-term electrochemical performance. In this work, NMC cathode powders were synthesized via a one-pot oxalate co-precipitation route, followed by structural characterization using X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and ion scattering spectroscopy (ISS). Electrochemical performance, including capacity retention, cycling stability, and internal resistance, was evaluated through galvanostatic charge–discharge (GCD) testing and electrochemical impedance spectroscopy (EIS). The core–shell configuration delivered higher specific discharge capacity compared to the individually synthesized core-only and shell-only reference materials, and the incorporation of a tungsten oxide interlayer resulted in a twofold increase in cycle life. These results demonstrate that tungsten oxide effectively enhances cycling stability by inhibiting core–shell interdiffusion, offering a promising pathway toward more durable high-Ni NMC cathodes. Full article

This study examined the geopolymerization behavior of granite waste powder and reactive silica powder (GWS), utilizing granite waste powder as a sustainable precursor material, to develop an environmentally friendly substitute for Ordinary Portland cement. To obtain this objective, a total of three different mixes of calcined granite waste with reactive silica (1:1, 3:2, 7:3) were cast to evaluate the aim of this study. Due to low inherent reactivity of granite waste powder, the alkali activation was achieved using a combined solution of alkali activators consisting of 8 mol/L concentration of NaOH and Na₂SiO₃ solution at mass ratio of 1:1.2 prepared 24 h in advance to ensure complete dissolution and stabilization prior to pouring it into the GWS paste. The finest particle size distribution for optimal reactivity performance was achieved by choosing lowest median particles size from 4.0 μm–4.2 μm among all mixtures. ICP-MS analysis of granite waste and reactive silica showed the presence of silica (0.11% and 0.26% respectively) and calcium (49.61% and 38.92% respectively) content adequate for effective geopolymerization of the paste. The elemental composition, new phase formation and microstructural analysis were examined using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR) techniques and Scanning Electron Microscopy (SEM) analysis. XRD analysis revealed that all GWS mixes were predominantly amorphous, with crystalline quartz, feldspar and minor α-cristobalite peaks diminishing from GWS50 to GWS70 confirming increased reactivity due to enormous reactive silica content. FTIR spectra of GWS mixes displayed characteristics of O-H (3375 cm⁻¹), H-O-H (1645 cm⁻¹), and Si-O-T (982–1000 cm⁻¹) bands, with the main Si-O-T peak shifting to higher wavenumbers from GWS50 to GWS70 due to increased GW content, indicating reduced geopolymerization effect in GWS50. SEM analysis revealed that among all mixes, GWS70 exhibited the most ideal dense matrix with increasing content of granite waste along with strong N-A-S-H gel formation. Compressive strength at 28 days increased from 11.2 MPa for GWS50 to 14.2 MPa for GWS60 and 13.8 MPa for GWS70, demonstrating that higher reactive silica powder content significantly enhanced the mechanical performance of the alkali-activated paste. These findings demonstrated that alkali-activated geopolymers of GSW offer a viable alternative to Ordinary Portland cement with optimized mixes by valorizing industrial waste and reducing reliance on high-carbon cement production. Full article

This study reports the development and characterization of chitosan–poly(vinyl alcohol) (CH/PVA) nanofibers (NFs), functionalized with bioactive compounds (ACs) relevant for wound healing and tissue regeneration. CH/PVA NFs loaded with L-arginine (ARG), allantoin (ALA), royal jelly (RJ) and curcumin (CUR), either as single or co-loaded systems, were prepared by electrospinning. The polymer solutions were characterized in terms of key physicochemical properties relevant to electrospinning. The CH/PVA@ACs NFs were characterized morphologically and structurally through scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). Additionally, surface-related, physical, and functional properties such as wettability, swelling behavior, and in vitro release profiles were examined. The NFs were successfully produced in a uniform and continuous manner, with the fiber diameter and morphology being influenced by the type of ACs. FTIR analysis validated the characteristic functional groups linked to both the polymeric matrix and ACs. The nanofibrous systems demonstrated a high swelling capacity and a release behavior that is dependent on pH. Analyses of surface free energy and wettability revealed favorable interfacial interactions between solid and liquid, indicating compatibility with aqueous biological environments. In summary, the developed CH/PVA@ACs NFs exhibited appropriate morphological, structural, surface, and functional properties, underscoring their potential as effective materials for wound dressings. Full article

Ultrathin two-dimensional (2D) coatings exhibit functional properties that are strongly defined by morphological features such as sheet edges, fracture sites, overlaps, folds, and local thickness variations, which are often difficult to resolve using conventional scanning electron microscopy (SEM) configurations. Here, we introduce a grazing-incidence SEM approach based on controlled sample tilting close to 90° for enhancing surface sensitivity and morphological feature detectability in ultrathin coatings. The method is proved on colloidal MoS₂ nanosheet coatings prepared by liquid-phase exfoliation. Optical absorption spectroscopy confirms the presence of mono- and few-layer MoS₂ nanosheets in the dispersion, confirming the ultrathin nature of the deposited coating. Compared to standard 0° imaging, grazing-incidence SEM reveals clearer boundaries and discontinuities. Quantitative Sobel-based image analysis supports these observations, showing an increase in edge density from 5.9% to 7.6% and in average gradient magnitude from 0.151 to 0.172 a.u. under grazing incidence, indicating a higher amount of retrievable morphological information. The proposed approach relies only on standard stage tilting and provides a broadly applicable framework for the surface-sensitive morphological characterization of ultrathin 2D coatings and thin films. Full article

The construction sector faces increasing pressure to reduce the embodied energy of building materials while valorizing industrial waste streams. This study evaluates the direct incorporation of post-industrial textile waste (100% cotton and cotton–polyester blends) in its native form to develop high-performance cementitious ceiling sheets. Composites were fabricated under a controlled hydraulic compaction pressure of 2.0 MPa, optimized to achieve matrix densification while preserving the integrity of the fibrous network. Viscoelastic recovery of the compressed fibers induced a hierarchical double-porosity architecture characterized by macro-voids and hollow fiber lumens. This microstructural evolution reduced thermal conductivity to 0.091 W/m·K, approximately 50% lower than commercial cement–fiber benchmarks—without compromising mechanical compliance. Scanning Electron Microscopy (SEM) revealed a mechanistic decoupling between water absorption and dimensional stability. Although the CP15 formulation (15 wt.% cotton–polyester) exhibited high moisture uptake (~21%), thickness swelling remained limited to 1.35%. This dimensional stability is attributed to the hydrophobic polyester framework, which bridges microcracks and constrains hygroscopic expansion within the cellulosic phase. The optimized CP15 composite achieved a Modulus of Rupture (MOR) of 8.75 MPa, exceeding ISO 8336 Category C, Class 2 requirements. Despite increased thickness, the areal density (10.84 kg/m²) remains compatible with standard gypsum-grade suspension systems, eliminating the need for structural modification. These findings establish a scalable, direct-valorization strategy for circular construction materials delivering enhanced thermal insulation and robust performance under tropical climatic conditions. Full article

An innovative preparation route for iron-based soft magnetic materials is presented, focusing on the influence of the mechanical surface treatment of powder particles on their structural and magnetic properties. High-purity Fe (99.98% purity) and FeNiMo (supermalloy) powders were mechanically milled (ball-to-powder ratio of 6:1; 120 min), surface-treated by controlled milling, coated with an inorganic SiO₂ insulating layer, and subsequently compacted into ring-shaped specimens. Structural characterization was carried out using optical microscopy and scanning electron microscopy. Magnetic properties were evaluated by hysteresis loop measurements, initial magnetization curves, and coercivity analysis at 200 K. The results demonstrate that mechanical surface treatment improves the homogeneity and continuity of the SiO₂ insulating layer. This improvement leads to reduced coercivity from 2100 to 1980 A·m⁻¹ for Fe powders, while FeNiMo powders showed a decrease from 1990 to 1910 A·m⁻¹, along with lower energy losses. The proposed method provides a laboratory-scale approach for studying the influence of powder surface treatment on the magnetic behavior of Fe-based soft magnetic composites. Full article

Delamination is a major failure Mode in laminated composites, typically triggered by premature interlaminar matrix cracking and leading to severe structural degradation. To address this, various through-thickness reinforcement strategies have been explored, including three-dimensional woven architecture. Although these designs significantly improve delamination resistance, their industrial adoption stays limited due to reproducibility challenges and the high cost and operational complexity of advanced manufacturing systems needed for controlled through-thickness reinforcement. This study investigates an alternative interlaminar reinforcement method, through-thickness stitching, aimed at enhancing Mode-I delamination resistance of a commercial fiberglass laminate without changing its native architecture. Composites were manufactured using a low-viscosity epoxy infusion system (MAX 1618 A/B) and a [0/90] biaxial fiberglass fabric. An eight-filament polyethylene thread (Ø = 0.12 mm) was introduced in predefined stitch architectures consisting of three longitudinal patterns having two, three, and five continuous stitch lines, referred to as AV, BV and CV samples, respectively. Results show that stitching highly increases Mode-I interlaminar fracture toughness G_IC by 0.3808, 0.4152 and 0.5192 kJ/m² for AV, BV and CV respectively, compared to 0.0265 kJ/m² for the unstitched composite O, highlighting the strong influence of stitch orientation and spacing on interlaminar performance. But scanning electron microscopy revealed added failure mechanisms in stitched specimens, including localized fiber misalignment of up to 33° and resin-rich regions approximately 0.6 mm in length, suggesting that while stitching enhances delamination resistance, it may also influence other mechanical properties. Full article

This study presents the fabrication and optimization of eco-efficient epoxy composites reinforced with ground natural stone fillers, namely pebble, sandstone, and marble, at loadings of up to 15.6 wt.%. Low content of a bio-based modifier, modified castor oil (MCO ≈ 0.5 wt.%), is incorporated to improve filler dispersion, processing behavior, and matrix–filler interfacial compatibility. The composites are designed to enhance mechanical, thermal, and dielectric performance using low-cost, abundant, and environmentally sustainable constituents. An experimental optimization approach is employed to evaluate and optimize bulk density, Shore D hardness, thermal conductivity, dielectric constant, and tensile strength. The results demonstrate that pebble-reinforced composites exhibit the highest tensile strength (≈30 MPa) and surface hardness (≈82 Shore D), which are attributed to the angular morphology and high intrinsic rigidity of pebble particles. Marble-filled systems show superior thermal stability, with residual mass increasing from approximately 2.5 wt.% for neat epoxy to over 11 wt.% at 550 °C, owing to the thermally stable calcium carbonate phase. In contrast, sandstone-reinforced composites exhibit the lowest dielectric constant (≈3.2), indicating enhanced electrical insulation capability. Fourier–transform infrared spectroscopy (FTIR) results confirm that the epoxy network structure is preserved upon filler incorporation, while MCO promotes improved interfacial interactions through physical interactions. Thermogravimetric analysis (TGA) and scanning electron microscopy (SEM) reveal enhanced thermal resistance, reduced microvoid formation, and improved filler–matrix adhesion at optimal filler contents of approximately 3.5 wt.%. Full article

Indoor climbing gyms are high-occupancy settings, yet integrated indoor air quality (IAQ) studies that analyze objective exposure and occupant perception remain scarce. The novelty consists of combining user perception with multi-zone, high-resolution IAQ measurements. We investigated a climbing gym in Romania to (i) quantify particulate matter (PM₁, PM_2.5, PM₁₀) and carbon dioxide (CO₂), (ii) compare natural and mechanical ventilation under real operating conditions with per capita normalization, (iii) relate exposure to occupancy and user perception, and (iv) coupling continuous optical monitoring with 24 h gravimetric and morphological/chemical analyses (scanning electron microscopy, confocal microscopy, X-ray fluorescence, and inductively coupled plasma mass spectrometry). The gravimetric 24 h reference measurements (EN 12341:2014) showed that daily means for PM_2.5 and PM₁₀ were 1.9–2.0× and 2.3–2.8× higher than the WHO guideline values, which confirms persistent daily particulate loads. Mechanical ventilation reduced coarse PM and CO₂, but absolute PM remained elevated and fine fractions persisted. CO₂ revealed a near-uniform vertical mixing, confirming dilution but indicating that CO₂ is not a surrogate for particulate exposure. Survey responses from occupants revealed a gap between perception and reality: most of the users rated IAQ as good despite high PM. This study is among the few integrations of perception of IAQ for climbing gyms and the first comprehensive assessment in Romania, providing evidence-based recommendations on ventilation and filtration upgrades, chalk use management, and dust-reservoir control, thus creating sparkling interest for IAQ researchers, building services engineers, sports facilities operators, and policymakers. Full article

The generic delimitation of the two closely related Rosaceae genera, Eriobotrya and Rhaphiolepis, has not yet been investigated by a detailed study of their pollen morphology using scanning electron microscopy. To provide novel diagnostic features and insights into their relationships, we examined the pollen grains of thirty-one species of Eriobotrya and Rhaphiolepis, analyzing five quantitative and two qualitative morphological variables. The findings revealed that Eriobotrya and Rhaphiolepis pollen grains are tricolpate monads that are small to medium in size and vary in shape from prolate to perprolate, predominantly featuring striate ornamentation. Notably, striate-perforate and psilate exine sculptures were found only in Eriobotrya species, while scabrate ornamentation was unique to Rhaphiolepis. The rugulate pattern appeared in both genera. Eriobotrya (E. malipoensis K.C.Kuan) had the smallest pollen grains and the shortest distance between the apices of two ectocolpi, while Rhaphiolepis (R. integerrima Hook. & Arn.) had the largest. Multivariate cluster analysis separated all species from both genera into two distinct clusters. Cluster I contained all Eriobotrya species, whereas Cluster II included all Rhaphiolepis species, demonstrating their morphological distinctness and alignment with recent micro-morphological and molecular evidence. Furthermore, the pollen profile of E. seguinii Cardot ex Guillaumin affirms its taxonomic placement within Eriobotrya. We conclude that pollen morphology offers diagnostic information for delimiting these genera. The observed ornamentation pattern of a shared striate background, with distinct derived ornamentation in each genus, provides a clear morphological foundation for evolutionary investigations within the Maleae tribe. To further clarify generic boundaries and evolutionary processes, future research should integrate these palynological data with micromorphological analyses of other plant parts and genomic information. Full article