Search Results (2,520)

It is known that approximately 8% of atmospheric carbon dioxide (CO₂) emissions originate from cement production. Consequently, there is ongoing rapid research into environmentally friendly and alternative materials that could substitute for cement. Olivine [(Mg, Fe)₂SiO₄] is an abundant mineral in the Earth’s crust that facilitates CO₂ sequestration due to its high solubility. This study investigates the effects of hydration mechanisms in olivine-substituted cement mortars on their compressive strength, microstructural characteristics, and physical properties. For this purpose, standard cement mortars were produced using CEM IV 32.5 N-type cement with olivine substitution rates of 0%, 10%, and 20%. The compressive strength of the specimens was initially determined at 7, 28, and 90 days. Subsequently, the hydration mechanisms at 7, 28, and 90 days were characterized using X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FT-IR), Differential Thermal Analysis/Thermogravimetric Analysis (DTA/TG), and Scanning Electron Microscopy-Energy Dispersive Spectroscopy (SEM-EDS). The results demonstrated that the 10% substitution rate complies with the BS EN 196-1 standard, and olivine can be substituted for CEM IV type cement up to 10% without requiring calcination. Full article

Phosphogypsum represents a gypsum-based solid waste originating from phosphoric acid production, which can be exploited for road filling after cement modification. This study delved into the composition design of high-volume phosphogypsum road base materials, aiming to ascertain their feasibility for subgrade filling, and refine the mix ratio. The main content of phosphogypsum was set at three high-proportion intervals of 86%, 88% and 90%, while the total content of inorganic curing agent was fixed at 0.5% of the total material. Within such a total amount, the proportion of bentonite was preserved at 20%, whereas the proportion of waterproofing agent was configured at three gradients of 20%, 25% and 30%, with the remaining part supplemented by powdered sodium silicate. Merged with trace amounts of inorganic curing agents, particularly the waterproofing agent component, the composite cementitious system comprising cement and ground granulated blast-furnace slag (GGBS) was leveraged to augment the key road performance and water stability of high-volume phosphogypsum-based materials. Material strengths were observed to be distinguishable under an array of phosphogypsum contents, which could be explained by the varying proportions of cement, GGBS and waterproofing agent. The test samples and microscopic products were dissected via XRD and SEM, demonstrating that the hydration products of the materials were predominantly C-S-H gel and ettringite crystals. Full article

Cold denaturation of gluten proteins during prolonged frozen storage or repeated freeze–thaw cycles can severely affect the quality of frozen cereal products. While both processes have been studied individually, their combined effects and underlying mechanisms remain unclear. This study systematically evaluated the hydration properties and conformational changes in gluten proteins stored at −73 °C and −23 °C, with or without freeze–thaw cycling. Compared to continuous storage, freeze–thaw cycles reduced water-holding capacity by 9.1–12.2% and increased oil-holding capacity by 5.3–10.3%, indicating aggravated structural damage. Ultra-low temperature storage (−73 °C) suppressed ice crystal growth, preserved hydration, and limited hydrophobic residue exposure. Spectroscopic analyses revealed a temperature-dependent shift from α-helices to β-sheets and β-turns, which was accelerated by freeze–thaw cycles. Enhanced hydrophobic interactions and tryptophan exposure further indicated destabilization. Molecular dynamics simulations showed that increased hydrogen bonding between proteins and water contributed to unfolding at low temperatures, while temperature fluctuations intensified denaturation through repeated hydrogen bond breakage and reformation. These results underscore the critical role of thermal instability in cold denaturation and offer mechanistic insights for improving cryoprotection strategies in frozen food systems. Full article

In this paper, a novel venturi jet reactor is innovatively proposed for the process of hydrazine hydrate production using the urea method. In order to investigate the performance of this reactor in depth, we used the computational fluid dynamics method to optimize the design of the structure of the new venturi jet reactor based on the flow field condition, the degree of mixing uniformity, and the efficiency of the reactor using the component transport model. The results showed that the moderate increase of the distance of mixing tube to nozzle and nozzle diameter seven could help to improve the efficiency of the jet reactor; however, in terms of the mixing effect, the increase of the distance of mixing tube to nozzle led to the mixing effect to be enhanced and then weakened, while the increase in the nozzle diameter was not conducive to the full mixing of the two fluids. In addition, the effects of ratio of throat length to diameter and constriction angle on the efficiency of the jet reactor showed nonlinear characteristics, and the optimal values existed in the study range. Based on the above analysis, this paper determines the optimal range of structural parameters, i.e., the distance of mixing tube to nozzle of 7–13 mm, the nozzle outlet diameter of 5–7 mm, the ratio of throat length to diameter of 3–5, and the constriction angle of 30–40°, and the study provides guidance for the industrial application of the venturi jet reactor. Full article

Aeolian sand is the primary geological material for construction in desert regions, and its stabilization with industrial solid wastes-based geopolymer (ISWG) provides an eco-friendly treatment replacing cement. This study comparatively investigated the enhancement effects of chemical activators and expansive agents on compressive strength of aeolian sand stabilized by ISWG (ASIG). Three chemical activators—NaOH, Ca(OH)₂, and CaCl₂—along with two expansive agents—desulfurized gypsum and bentonite—were considered. Through X-ray diffraction, thermogravimetric analysis, scanning electron microscopy, mercury intrusion porosimetry and pH values tests, the enhancement mechanisms of the additives on ASIG were elucidated. Results demonstrate that the expansive agent exhibits significantly superior strengthening effects on ASIG compared to the widely applied chemical activators. Chemical activators promoted ISWs dissolution and hydration product synthesis, thereby densifying the hydration product matrix but concurrently enlarged interparticle pores. Desulfurized gypsum incorporation induced morphological changes in ettringite, and excessive desulfurized gypsum generated substantial ettringite that disrupted gel matrix. In contrast, bentonite demonstrated superior pore-filling efficacy while densifying gel matrix through a compaction effect. These findings highlight bentonite superior compatibility with the unique microstructure of aeolian sand compared to conventional alkaline activators or expansive agents, and better effectiveness in enhancing the strength of ASIG. Full article

Background: Niacinamide exhibits a wide range of beneficial properties that support its use in skincare and the treatment of various dermatological conditions. This study aimed to evaluate skin hydration and to assess participants’ subjective perceptions of skin tone and overall skin condition following the use of a commercial niacinamide-containing preparation compared to usual skin care and a ceramide-containing preparation. Methods: Young adult women were enrolled and assigned to one of three groups: continued use of their usual skincare, application of a ceramide-containing cream, or application of a niacinamide-containing cream. The study period lasted three weeks. Skin hydration was measured using corneometry, and changes in skin appearance were documented through standardized photography and participant self-assessments. Results: Of the 50 participants enrolled, 46 completed the study. The niacinamide-containing cream significantly improved skin hydration (32.15 ± 12.61 vs. 39.09 ± 14.12; p = 0.0365) and reduced skin discoloration, with 81.2% of participants reporting improvement (p = 0.0407). The ceramide-containing cream was most effective in reducing redness, with 68.8% of participants noting visible improvement (p = 0.0017). No significant changes were observed in skin texture or the appearance of skin lesions across the tested groups. Conclusions: Use of a niacinamide-containing commercial cream resulted in measurable improvements in skin hydration and tone. A key strength of this study is its focus on real-life product application, offering practical insights into the performance of commercial skincare products under typical user conditions. Future studies should include additional objective measurements and larger, more diverse populations to enhance the reliability and generalizability of the results. Full article

As mining operations extend deeper underground, support structures are increasingly subjected to severe impact loads. The dynamic mechanical performance of column-type support systems has, therefore, become a pressing concern. In the present research, a Split Hopkinson Pressure Bar (SHPB) apparatus, combined with Scanning Electron Microscopy (SEM), is used to systematically examine how the water-to-cement ratio, number of carbon-fiber reinforced polymer (CFRP) layers, and strain rate influence the dynamic compressive behavior and microstructural evolution of CFRP-confined high-water material. The results indicate that unconfined specimens are strongly strain rate-dependent, with peak strength following a rise–fall trend. A lower water–cement ratio results in a denser internal structure and improved strength. Additionally, CFRP confinement markedly enhances peak strength and impact resistance, refines failure modes, and promotes the formation of denser hydration products by limiting lateral deformation. This confinement effect effectively mitigates microstructural damage under high strain rates. These findings clarify the reinforcement mechanism of CFRP from both macroscopic and microscopic perspectives, offering theoretical insights and engineering references for the design of impact-resistant support systems in deep mining applications. Full article

Engineering phase-selective gel composites presents a promising route to enhance both CO₂ adsorption and conversion efficiency in photocatalytic systems. In this work, Cu₉S₅/TiO₂ gel composites were synthesized via a hydrazine-hydrate-assisted hydrothermal method, using TiO₂ derived from a microwave-assisted sol–gel process. The resulting materials exhibit a porous gel-derived morphology with highly dispersed Cu₉S₅ nanocrystals, as confirmed by XRD, TEM, and XPS analyses. These structural features promote abundant surface-active sites and interfacial contact, enabling efficient CO₂ adsorption. Among all samples, the optimized 0.36Cu₉S₅/TiO₂ composite achieved a methane production rate of 34 μmol·g⁻¹·h⁻¹, with 64.76% CH₄ selectivity and 88.02% electron-based selectivity, significantly outperforming Cu₉S₈/TiO₂ synthesized without hydrazine hydrate. This enhancement is attributed to the dual role of hydrazine: facilitating phase transformation from Cu₉S₈ to Cu₉S₅ and modulating the interfacial electronic environment to favor CO₂ capture and activation. DFT calculations reveal that Cu₉S₅/TiO₂ effectively lowers the energy barriers of critical intermediates (*COOH, *CO, and *CHO), enhancing both CO₂ adsorption strength and subsequent conversion to methane. This work demonstrates a gel-derived composite strategy that couples efficient CO₂ adsorption with selective photocatalytic reduction, offering new design principles for adsorption–conversion hybrid materials. Full article

Small ruminant production is a significant sector of agricultural industry in Texas, USA. Heat stress has a negative effect on productivity and animal health. Cholecalciferol, a form of vitamin D₃, may enhance the function of immune cells and help ensure healthy immune function in farm animals exposed to heat stress. Practical applications of vitamin D₃ against infectious diseases can benefit from the protective effects of a delivery system comprised of soy protein isolate and stachyose in emulsion gel. The prebiotic oligosaccharide stachyose has shown to have a great potential as a substrate for beneficial intestinal bacteria, which are thought to modulate the immune system. Cellular and humoral immunity are both impaired in dairy animals under heat stress. The delivery of vitamin D₃ embedded within the soy protein isolate-stachyose emulsion gel resulted in a marked increase in 25-hydroxyvitamin D₃ [25-(OH)-D₃] concentration in blood serum. Chicken egg albumin (OVA)-immunized goats produced low anti-OVA immunoglobulin G (IgG) responses. In contrast, OVA-immunized goats fed vitamin D₃ within the soy protein isolate-stachyose emulsion gel diet strongly stimulated antibody production. These results show that anti-OVA IgG responses can be modulated in dairy goats using vitamin D₃, particularly if this vitamin is delivered in the form of emulsion gel. The results seem to depend on the highly hydrated gel matrix of soy protein isolate-stachyose at the low pH of the stomach as monitored by oxygen-17 (¹⁷O) and proton (¹H) nuclear magnetic resonance (NMR). In addition, the prebiotic nature of stachyose may boost beneficial gut bacteria, most notably for immune health and reducing the risk of infectious diseases. Full article

The utilization of high-volume fly ash (HVFA, ≥50% cement replacement) in concrete is pivotal for sustainable construction but hindered by low early-age strength. This study investigates the individual and combined effects of hydrated lime (HL) and calcium formate (CF) on the strength development, hydration kinetics, and microstructure of HVFA pastes (60% and 70% FA). Individual additions of 11% HL (HVFA60) or 14% HL (HVFA70) raised 28-day compressive strength by 18% and 22%, respectively, and shortened final setting from 10.0 h to 3.8 h. Similarly, 3% CF increased 28-day strength by 15% (HVFA60) and 12% (HVFA70) while cutting final setting to 2.1 h and 3.3 h. In contrast, combining HL and CF suppressed strength by 15–22% despite accelerating final setting to less than 1 h. Isothermal calorimetry showed a 40% reduction in cumulative heat release at 44 h for the combined system. XRD, TGA and SEM confirmed 20–30% lower C-S-H content, 25% less CH, and a rise in porosity when HL and CF were used together. These findings demonstrate that HL and CF act as competing accelerators, where rapid heat release compromises microstructural integrity. For practical applications using HVFA materials, individual use of HL or CF is recommended to enhance early-age performance, while combined application should be avoided to prevent strength reduction. Full article

Extracellular vesicles (EVs) have gained attention in the cosmetics industry for their role in intercellular communication and tissue regeneration. They transfer bioactive molecules such as proteins, lipids, and nucleic acids, promoting skin repair, rejuvenation, and anti-aging effects. Human mesenchymal stem cell-derived EVs are particularly valued for their ability to enhance collagen production, reduce inflammation, and improve skin texture and hydration. However, their use is prohibited by regulatory agencies. Plant- and bacterial-derived EVs are being explored to meet the demand for innovative cosmetics. Despite their potential, challenges such as regulatory approval, high production costs, and product stability need to be addressed to fully realize the benefits of EV-based cosmetics. This paper examines the mechanisms, benefits, market trends, and prospects of EV-based skincare products, highlighting their transformative impact on the cosmetic industry. Full article

Objectives: Skin aging, often accelerated by dietary advanced glycation end products (AGEs), poses both cosmetic and health challenges. This study explores the protective effects of hydroxytyrosol (HT), a potent antioxidant found in olives, against AGEs-induced skin aging in mice. Methods: A total of forty-eight 8-month-old specific pathogen-free (SPF) male C57BL/6J mice were randomly assigned to one of four groups: control, model, low-dose hydroxytyrosol (HT25), and high-dose hydroxytyrosol (HT50). An additional group of six 6-week-old SPF male C57BL/6J mice served as the youth group. The experimental period lasted 16 weeks. Following the intervention, skin, serum, and ileum samples were collected. Results: The results demonstrated that HT50 significantly increased skin moisture, epidermal thickness, and dermal thickness (p < 0.05). HT50 also significantly elevated hydroxyproline levels as well as superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activities in the skin while reducing malondialdehyde (MDA) content (p < 0.05). Furthermore, HT50 significantly reduced the levels of interleukin-6 (IL-6), interleukin-1β (IL-1β), and tumor necrosis factor-α (TNF-α) (p < 0.05). Regarding intestinal integrity, hydroxytyrosol intervention (either HT25 or HT50) significantly increased the positive staining ratios of zonula occludens-1 (ZO-1) and occludin in the ileum (p < 0.05). Conclusions: HT improves skin hydration, thickness, and collagen levels while reducing oxidative stress and inflammation. Notably, HT also enhances intestinal barrier function, suggesting a role for the gut–skin axis. These findings highlight HT’s potential as a natural intervention for skin aging. Full article

The aim of this study is an interdisciplinary assessment of the potential of cement pastes to permanently bind carbon dioxide (CO₂) under anaerobic digestion conditions, considering technological, microstructural, environmental, and economic aspects. The research focused on three types of Portland cement: CEM I 52.5N, CEM I 42.5R-1, and CEM I 42.5R-2, differing in phase composition and reactivity, which were evaluated in terms of their carbonation potential and resistance to chemically aggressive environments. The cement pastes were prepared with a water-to-cement ratio of 0.5 and subjected to 90-day exposure in two environments: a reference environment (tap water) and a fermentation environment (aqueous suspension of poultry manure simulating biogas reactor conditions). XRD, TG/DTA, SEM/EDS, and mercury intrusion porosimetry were applied to analyze CO₂ mineralization, phase changes, and microstructural evolution. XRD results revealed a significant increase in calcite content (e.g., for CEM I 52.5N from 5.9% to 41.1%) and the presence of vaterite (19.3%), indicating intense carbonation under organic conditions. TG/DTA analysis confirmed a reduction in portlandite and C-S-H phases, suggesting their transformation into stable carbonate forms. SEM observations and EDS analysis revealed well-developed calcite crystals and the dominance of Ca, C, and O, confirming effective CO₂ binding. In control samples, hydration products predominated without signs of mineralization. The highest sequestration potential was observed for CEM I 52.5N, while cements with higher C₃A content (e.g., CEM I 42.5R-2) exhibited lower chemical resistance. The results confirm that carbonation under fermentation conditions may serve as an effective tool for CO₂ emission management, contributing to improved durability of construction materials and generating measurable economic benefits in the context of climate policy and the EU ETS. The article highlights the need to integrate CO₂ sequestration technologies with emission management systems and life cycle assessment (LCA) of biogas infrastructure, supporting the transition toward a low-carbon economy. Full article

This paper reviews various emerging alternative SCMs derived from minerals and biomass sources, industrial byproducts, and underutilized waste streams. The paper compiles and evaluates physicochemical properties, reaction mechanisms in cementitious systems, resource availability, supply chain dynamics, technology readiness, the impact on concrete performance, and environmental and cost factors for each candidate SCM. Specifically, the review examines wood ash from bioenergy plants, volcanic and sedimentary natural pozzolans, and construction and demolition waste. This includes recycled concrete fines, asphalt plants’ rock dust (baghouse fines), aggregate production fines, and post-consumer waste, particularly municipal solid waste incinerator ash and wastewater sludge ash. Additionally, the paper explores innovative additives such as cellulose and chitin nanomaterials and calcium–silicate–hydrate nanoseeds to address challenges of slower strength development and rheological changes. The key contribution of this review is a multifactor framework for assessing alternative SCMs, emphasizing availability, supply chain, market readiness, and environmental performance, combined with an engineering performance review. Full article

Hydrate-based CO₂ sequestration is considered one of the most promising methods in the field of carbon capture, utilization, and storage. The abundant fractured environments in marine sediments provide an ideal setting for the sequestration of CO₂ hydrate. Investigating the kinetics and morphological characteristics of CO₂ hydrate formation within fractures is a critical prerequisite for achieving efficient and safe CO₂ sequestration using hydrate technology in subsea environments. Based on the aforementioned considerations, the kinetic experiments on the formation, dissociation, and reformation of CO₂ hydrates were conducted using a high-pressure visualization experimental system in this study. The kinetic behaviors and morphological characteristics of CO₂ hydrates within sandstone fractures were comprehensively investigated. Particular emphasis was placed on analyzing the effects of fracture width, type, and surface roughness on the processes of hydrate formation, dissociation, and reformation. The experimental results indicate the following: (1) At a formation pressure of 2.9 MPa, the 10 mm width fracture exhibited the shortest induction time, the longest formation duration, and the highest hydrate yield (approximately 0.52 mol) compared to the other two fracture widths. The formed CO₂ hydrates exhibited a smooth, thin-walled morphology. (2) In X-type fractures, the formation of CO₂ hydrates was characterized by concurrent induction and dissolution processes. Compared to I-type fractures, the hydrate formation process in X-type fractures exhibited shorter formation durations and generally lower hydrate yields. (3) An increase in fracture roughness enhances the number of nucleation sites for the formation of hydrates. In both fracture types (I-type and X-type), the induction time for CO₂ hydrate formation was nearly negligible. However, a significant difference in the trend of formation duration was observed under varying roughness conditions. (4) Hydrate dissociation follows a diffusion-controlled mechanism, progressing from the fracture walls towards the interior. The maximum gas production was achieved in the 10 mm-width fracture, reaching 0.24 mol, indicating optimal heat and mass transfer conditions under this configuration. (5) During the reformation process, the induction time was significantly shortened due to the “memory effect.” However, the hydrate yield after the reformation process remained consistently lower than that of the first formation, which is primarily attributed to the high solubility of CO₂ in the aqueous phase. Full article