Search Results (11,432)

This research investigates the feasibility of producing eco-friendly self-compacting concrete (SCC) by partially replacing both fine and coarse natural aggregates with waste marble sludge (WMS), a byproduct of the marble industry. The objective is to evaluate whether this substitution enhances or compromises the concrete’s performance while contributing to sustainability. A comprehensive experimental program was conducted to assess fresh and hardened properties of SCC with varying WMS content. Fresh-state tests—including slump flow, T₅₀ time, and V-funnel flow time—were used to evaluate workability, flowability, and viscosity. Hardened properties were measured through compressive, flexural, and Brazilian tensile strengths, along with water absorption after 28 days of curing. The mix with 10% replacement of both sand and coarse aggregate showed the most balanced performance, achieving a slump flow of 690 mm and a V-funnel time of 6 s, alongside enhanced mechanical properties—compressive strength 48.6 MPa, tensile strength 3.9 MPa, and flexural strength 4.5 MPa—and reduced water absorption (4.9%). A complementary cost model quantified direct material cost per cubic meter and a performance-normalized efficiency metric (compressive strength per cost). The cost decreased monotonically from 99.1 $/m³ for the base mix to $90.7 $/m³ at 20% + 20% WMS (−8.4% overall), while the strength-per-cost peaked at the 10% + 10% mix (0.51 MPa/USD; +12% vs. base). Results demonstrate that WMS can simultaneously improve rheology and mechanical performance and reduce material cost, offering a practical pathway for resource conservation and circular economy concrete production. Full article

Vanadium dioxide (VO₂) has become one of the most promising smart temperature-controlled thin-film materials due to its reversible phase transition between a metallic and an insulating state at approximately 68 °C, accompanied by negligible volume change and excellent optical modulation properties. However, the practical application of VO₂ is still limited by its relatively high phase transition temperature and susceptibility to oxidation. To address these two major shortcomings, this study employed a one-step hydrothermal method to prepare a VO₂ nanopowder, followed by a chemical precipitation method to form a VO₂@AlF₃ core–shell structure. The coated nanoparticles were then dispersed in a PVP ethanol solution, coated onto a glass substrate, and evaluated for performance. The experimental results indicate that when the molar ratio of VO₂ to AlF₃ reached 1:1, the phase transition temperature of VO₂@AlF₃ was effectively reduced to 50.3 °C, significantly lower than the original temperature of 68 °C. Additionally, the material exhibited favorable optical properties, with a solar modulation ability (ΔT_sol) of 17.2% and a luminous transmittance (T_lum) of 36.3%. After calcination in air at 300 °C for 3–6 h, the VO₂ core remained oxidation-resistant and maintained excellent phase-change thermal insulation properties. Full article

Hemp (Cannabis sativa L.) is a high-yielding crop cultivated for fiber and seed production, generating substantial lignocellulosic residues such as hurds. These byproducts can be valorized through pyro-gasification, a thermochemical process that offers a sustainable alternative to combustion and produces biochar—a promising soil amendment due to its ability to enhance soil quality and mitigate drought stress. This research explores the viability of utilizing industrial hemp hurds as a direct feedstock for biochar production within the context of agricultural exploitation. The study specifically focuses on assessing the feasibility of converting raw, unprocessed hemp hurds into biochar through pyrolysis. A comprehensive characterization of the resulting biochar is conducted to evaluate its properties and potential applications in agriculture, establishing a foundational understanding for future agronomic use. Specific analysis included proximate and ultimate analysis, thermogravimetric analysis (TGA), SEM-EDS, and phytotoxicity testing. The biochar exhibited an alkaline pH (≥9), a low H/C ratio (0.37), and suitable macro- and micronutrient levels. Microstructural analysis revealed a porous architecture favorable for nutrient retention and water absorption. Germination tests with corn (Zea mays L.) showed a germination index above 90% for substrates containing 0.5–1% biochar. These findings establish a foundation for future research aimed at thoroughly exploring the agricultural potential of this material. Full article

The rapid and sensitive detection of regulatory elements within transgenic constructs of genetically modified organisms (GMOs) is essential for effective monitoring and control of their distribution. In this study, we present several innovative electrochemical biosensing platforms for the detection of regulatory sequences in genetically modified (GM) plants, combining the loop-mediated isothermal amplification (LAMP) method with electrodes functionalized by two-dimensional (2D) nanomaterials. The sensor design exploits the high surface area and excellent conductivity of reduced graphene oxide, Ti₃C₂T_x, and molybdenum disulfide (MoS₂) to enhance signal transduction. Furthermore, we used a “green synthesis” method for Ti₃C₂T_x preparation that eliminates the use of hazardous hydrofluoric acid (HF) and hydrochloric acid (HCl), providing a safer and more sustainable approach for nanomaterial production. Within this framework, the performance of various custom-fabricated electrodes, including laser-patterned gold leaf films, physical vapor deposition (PVD)-deposited gold electrodes, and screen-printed gold electrodes, is evaluated and compared with commercial screen-printed gold electrodes. Additionally, gold and carbon electrodes were electrochemically covered by gold nanoparticles (AuNPs), and their properties were compared. Several electrochemical methods were used during the DNA detection, and their importance and differences in excitation signal were highlighted. Electrochemical properties, sensitivity, selectivity, and reproducibility are characterized for each electrode type to assess the influence of fabrication methods and material composition on sensor performance. The developed biosensing systems exhibit high sensitivity, specificity, and rapid response, highlighting their potential as practical tools for on-site GMO screening and regulatory compliance monitoring. This work advances electrochemical nucleic acid detection by integrating environmentally-friendly nanomaterial synthesis with robust biosensing technology. Full article

The processing of freshly cut fruits and vegetables represents an important niche for implementing circular economy principles, particularly through the reuse of washing water. This is especially relevant as post-wash water is often treated as wastewater and discarded without reuse. One promising research avenue is the use of plant-derived extracts in water sanitation processes. Their antimicrobial properties offer a natural alternative to conventional disinfectants while reducing the formation of harmful disinfection by-products. The aim of this study was to evaluate the effectiveness of different filter bed configurations in removing pathogens from water. These configurations included a hydrogel saturated with natural plant extracts, an ion exchange resin layer, and an activated carbon layer. The most effective composite was also tested using real process water from a fruit washing line. The test materials included concentrated extracts from oak bark (Quercus robur), willow (Salix alba), birch (Betula pendula), raspberry shoots (Rubus idaeus), tea leaves (Camellia sinensis), and linden flowers (Tilia cordata), all immobilized in hydrogel, along with activated carbon and ion-exchange resin. Water samples were artificially inoculated with six opportunistic pathogens and collected process water was also used. Samples were analyzed microbiologically at six time intervals. The composite filter (hydrogel–resin–carbon) achieved a reduction of over 2 log₁₀ in heavily inoculated water (~10⁸ CFU mL⁻¹) and maintained at least a 1 log₁₀ reduction in real process effluents. The proposed solution supports blue water footprint reduction strategies (as the system aims to decrease the demand for freshwater resources through the reuse of treated wastewater) and aligns with the principles of green processing. Full article

This study investigates the effects of welding parameters and the addition of a buffer layer on the morphology, microstructure, mechanical properties, and corrosion resistance of the overlay layer during overlay welding. This paper uses Q235 steel as the base material, ER309L as the buffer layer, and ER347 as the overlay layer to conduct process experiments on overlay welding component, aiming to obtain optimal process parameters. The effects of welding line energy and weld bead overlap rate on the morphology, dimensions, and dilution rate of the overlay layer were analyzed. Furthermore, the influence of the presence or absence of the buffer layer on the microstructure, mechanical properties, and corrosion resistance of the overlay layer was investigated. The microstructure and morphology of the overlay layer were characterized by optical microscopy (OM), scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS). Mechanical and electrochemical tests were also performed to evaluate the mechanical and corrosion resistance properties of ER347 stainless steel weld overlays. The results showed that the optimal process parameters were successfully obtained, which ensured sound weld bead formation while minimizing dilution. The addition of the buffer layer (ER309L) improved the bonding quality of the overlay welding component interface, reduced element dilution in the overlay layer, significantly improved hardness distribution, and reduced sudden changes in hardness in the fusion zone, thereby optimizing the mechanical properties of the ER347 stainless steel overlay layer. After adding the buffer layer, the corrosion current density decreased from 6.23 × 10⁻⁵ A·cm⁻² to 2.21 × 10⁻⁵ A·cm⁻², and the corrosion potential increased from −1.049 V to −0.973 V, effectively reducing the corrosion risk of the overlay component. This study innovatively introduced a buffer layer in the process of overlay welding austenitic stainless steel on low-carbon steel and investigated the impact of the overlay welding process on the overlay layer, thereby contributing to a comprehensive understanding of the overlay welding process from multiple perspectives. Full article

Microbial Induced Carbonate Precipitation (MICP) is regarded as a promising eco-friendly alternative to traditional Portland cement for soil stabilization. However, the feasibility of applying bio-cemented soil as a road base material remains inadequately studied, particularly in terms of the relationships between MICP treatment parameters—such as solution content, curing age, and the ratio of bacterial solution (BS) to cementation solution (CS) —and key mechanical and durability properties under realistic road conditions. In this study, an optimal curing condition for bio-cemented sand was first determined through unconfined compression strength (UCS) tests and calcium carbonate content (CCC) determination. Subsequently, dynamic triaxial tests were conducted to evaluate its resistance to cyclic loading. Further road performance tests, including splitting tensile strength, freeze-thaw resistance, temperature shrinkage, and arch expansion assessments, were carried out to comprehensively evaluate the material’s applicability. Scanning electron microscopy (SEM) was employed to elucidate the microstructural mechanisms underlying strength development. The results show that the strength (4.28 MPa) of bio-cemented sand cured under optimal conditions (12% bio-cured solution content, a BS-to-CS ratio of 1:4 and 7-d curing age) satisfies the criteria for road base applications. MICP treatment significantly improved the dynamic properties of aeolian sand (AS), reducing the cumulative plastic axial strain (ε_p) by nearly 11–46% and increasing the dynamic elastic modulus (E_d) by approximately 7–31% compared to untreated sand. The material also demonstrates satisfactory performance across all four road performance metrics. Microstructural analysis reveals enhanced interparticle bonding due to calcium carbonate precipitation, with samples prepared near the optimum moisture content exhibiting superior integrity and strength. Overall, bio-cemented sand demonstrates excellent potential as a sustainable road base material. These findings provide a theoretical foundation for practical applications of similar bio-cemented soils in road engineering. Full article

The growing interest in sustainable materials has encouraged the valorization of agro-industrial byproducts for pharmaceutical, nutraceutical, and food applications. This study evaluated yellow pitaya peel powder, obtained via convective and refractance window drying, as a diluent in immediate-release quercetin tablets. The powders were characterized by physicochemical, granulometric, morphological, and surface properties, and compared with conventional excipients, including partially pregelatinized corn starch and spray-dried lactose monohydrate. Refractance window drying improved solubility, flowability, and structural integrity, while convective drying produced finer, more porous particles with lower water activity. Tablets formulated with both powders showed adequate hardness, low friability, and disintegration times under five minutes. All systems achieved complete quercetin release. Kinetic modeling revealed anomalous, matrix-regulated transport, with Weibull and Modified Hill models providing the best fit. Based on these results, pitaya peel powder could be considered a suitable diluent for the development of immediate-release tablets, offering functional performance aligned with sustainable formulation strategies. Full article

This study aimed to evaluate how acidic and alkaline staining solutions affect the optical properties (mean color change, ΔE*), geometric characteristics (surface roughness, Ra), and bacterial adhesion of zirconia Ceramill Zolid PS computer-aided design/computer-aided manufacture (CAD/CAM) material after 21 days of immersion. Ninety-six zirconia CAD/CAM Ceramill Zolid multilayer PS specimens were prepared and allocated to eight groups based on the pH values of the immersion solutions; the acidic solutions included Mirinda Citrus, CodeRed, yerba mate tea, Saudi coffee, and Nescafe (A–E), and the alkaline solutions included artificial saliva, DZRT (tobacco-free nicotine pouches), and smokeless tobacco (F–H). The specimens were immersed for 21 days at 37 °C, with the solutions replaced every 12 h to ensure consistency. Color changes were measured using a VITA Easyshade V spectrophotometer, and Ra was evaluated via white-light interferometric microscopy. The bacterial adhesion of Streptococcus mutans was quantified by counting colony-forming units (CFUs, CFU/mm²). Statistical analyses included the Shapiro–Wilk test for normality, one-way ANOVA with Tukey’s HSD post hoc test for group comparisons, and paired t-tests, with significance set at <0.05. The recorded pH values of the staining materials ranged from acidic (Mirinda Citrus: 3.23) to alkaline (smokeless tobacco: 8.54). Smokeless tobacco caused the most unacceptable mean color change (ΔE* = 6.84), followed by DZRT (ΔE* = 6.46), whereas artificial saliva produced the least discoloration (ΔE* = 2.15), with statistically significant differences among the solutions (p < 0.001). The Ra measurements varied significantly (p < 0.001), with Nescafe demonstrating the lowest value (0.486 µm) and DZRT the highest (0.748 µm). S. mutans adhesion was the highest for CodeRed (546.75 CFU) and the lowest for smokeless tobacco (283.92 CFU), demonstrating significant variation across groups (ANOVA, p < 0.001). The acidic and alkaline solutions significantly altered the optical properties, Ra, and bacterial adhesion of zirconia Ceramill Zolid PS CAD/CAM, with acidic solutions leading to higher bacterial adhesion. Full article

The use of supplementary cementitious materials and the CO₂ uptake capacity of cementitious materials—including recycled concrete aggregates—not only promotes the circular economy but may also present an opportunity to increase their ecoefficiency, thus improving the shrinkage and durability properties of concretes. This study analyses the impact of carbonated recycled aggregates and CO₂ curing on improving the properties of commercial structural self-compacting concrete. Recycled aggregate concretes (RACs) were produced using 50% and 60% coarse recycled concrete aggregate (RCA), in carbonated and uncarbonated forms, and two types of cement—ordinary Portland cement (CEM I) and CEM II/B-M Portland composite cement containing 24% less clinker than CEM I—all with similar compressive strengths. After evaluating the CO₂ curing process, the physical, mechanical, shrinkage, and durability properties (including suction and carbonation resistance) of the concretes were assessed. The properties of the RACs were compared with those achieved by conventional concrete, to generate insights for developing a highly sustainable concrete manufacturing process. Taking all the assessed properties into account, the CO₂ curing process improved concrete’s properties. In addition, RAC-C50-I concrete (using CEM I with carbonated RCA) and RAC50-II (using CEM IIB and uncarbonated RCA) exhibited the greatest durability, resulting in reductions in sorptivity values of 40% and 45%, and decreases in the carbonation coefficient of 16% and 21%, respectively, compared to concrete without CO₂ curing. Full article

The development of adaptive and comfortable sports bras is essential for adolescents, who experience rapid changes in body morphology during growth. Traditional bras, often made with molded polyurethane bra pads, frequently fail to accommodate these variations, leading to discomfort and poor fit. This study investigates the design of a flexible-fit bra utilizing advanced knitting technology and bio-based materials, including organic cotton and renewable acetate, to enhance comfort and adaptability. The bra, crafted from bio-based yarns, offers stretchability, breathability, and fit, allowing it to adapt to various breast shapes and sizes. Such a bra design is particularly suitable for adolescents undergoing rapid growth. This study includes assessments of material properties and user feedback to evaluate the effectiveness of the design and identify areas for improvement. Positive results were reported from both material tests and subjective evaluations, confirming the effectiveness of the design. The seamless knitting minimizes irritation, while the inlay spacer fabric absorbs impact, and the pointelle structure improves moisture management. Adjustable components enhance adaptability and ensure a flexible fit. This study highlights the potential of knitted biomaterials for creating adaptive intimate apparel, offering a scalable solution for size-inclusive fashion. Full article

Hybrid fiber-reinforced concrete (HFRC), renowned for its significantly enhanced mechanical properties and structural integrity, is widely used in infrastructure construction and has become a key avenue of modern high-performance concrete development. The hybrid application of basalt fiber (BF) and polypropylene fiber (PPF) at optimized ratios generates synergistic effects, improving both mechanical performance and material service reliability. To explore and evaluate the synergistic mechanism of BF-PPF hybrid fibers on concrete’s mechanical properties and performance, this study employs an orthogonal experimental design and mechanical testing methods, measuring the materials’ static compressive strength (loading rate: 0.6 mm/min), splitting tensile strength (loading rate: 0.12–0.14 MPa/s), dynamic elastic modulus (measured by the ultrasonic method), and dynamic compressive strength (loading rates: 0.6 mm/min, 6 mm/min, and 60 mm/min). For these tests, we prepared 100 mm × 100 mm × 100 mm cubic specimens (for static compressive, dynamic compressive, and splitting tensile tests) and 400 mm × 100 mm × 100 mm prismatic specimens (for dynamic elastic modulus tests), with three parallel specimens in each test group. In addition, the microstructure was characterized by scanning electron microscopy (SEM) to observe the fiber-matrix interaction. The results show that when the BF/PPF volume ratio is 1:2 (BF0.05PPF0.1), the concrete’s compressive strength, splitting tensile strength, and elastic modulus increase by 13.7%, 76.3%, and 116.0%, respectively, with corresponding synergistic effect indices (Q) of 0.057, 0.213, and 0.241, indicating obvious positive synergy. Under dynamic loading, hybrid combinations with higher PPF content (e.g., BF0.05PPF0.1) exhibit strain-rate-dependent enhancements in compressive strength and better impact resistance. SEM analysis reveals that fibers inhibit microcrack propagation through fiber bridging, network distribution, and pull-out resistance, while also improving the interfacial transition zone’s structure. These findings provide theoretical support for the engineering application of composite fiber-reinforced concrete materials. Full article

Local variations in mechanical properties are commonly observed in engineering structures, driven by complex manufacturing histories and harsh service environments. The evaluation of mechanical properties accurately constitutes a fundamental requirement for structural integrity assessment. The Instrumented Indentation Technique (IIT) can play a critical role in the in-site testing of local properties. However, it could be often a challenge to correlate indentation characteristics with uniaxial stress–strain relationships. In this study, we investigated quantitatively the connection between the indentation responses of commonly used metals and their plastic properties using the finite element inversion method. Materials typically exhibit plastic deformation mechanisms characterized by either linear or power-law hardening behaviors. Consequently, conventional prediction methods based on a single constitutive model may no longer be universally applicable. Hence, this study developed methods for acquiring mechanical properties suitable for either the power-law and linear hardening model, or combined, respectively, based on analyses of microstructures of materials exhibiting different hardening behaviors. We proposed a novel integrated IIT incorporating microstructures and material-specific constitutive models. Moreover, the inter-dependency between microstructural evolution and hardening behaviors was systematically investigated. The proposed method was validated on representative engineering steels, including austenitic stainless steel, structural steel, and low-alloy steel. The predicted deviations in yield strength and strain hardening exponent are broadly within 10%, with the maximum error at 12%. This study is expected to provide a fundamental framework for the advancement of IIT and structural integrity assessment. Full article

Spot melting is an emerging alternative to traditional line melting in electron beam powder bed fusion, dividing a layer into thousands of individual spots. This method allows for an almost infinite number of spot arrangements and spot melting sequences to tailor material and part properties. To enhance the productivity of spot melting, the number of spots can be reduced by increasing the beam diameter. However, this results in rough surfaces due to the staircase effect. The classical approach to counteract these effects is to melt a contour that surrounds the infill area. Creating effective contours is challenging because the melted area ought to cover the artifacts from the staircase effect and avoid porosity in the transition area between the infill and contour, all while minimizing additional energy and melt time. In this work, we propose an algorithm for generating a spot melting sequence for contour lines surrounding the infill area. Additionally, we compare three different approaches for combining the spot melting of infill and contour areas, each utilizing a combination of large infill spots and small contour spots. The quality of the contours is evaluated based on optical inspection as well as the porosity between infill and contour using electron optical images, balanced against the additional energy input. The most suitable approach is used to build a complex brake caliper. Full article

Gold nanoparticles (AuNPs) are promising materials for the development of novel anticancer agents, and their green synthesis has become essential because of their numerous advantages. This study aimed to synthesize AuNPs using an ethanolic extract of Scabiosa palaestina, characterize their physicochemical properties, and evaluate their anticancer properties and antioxidant potential. AuNPs were successfully synthesized and characterized using UV–visible spectroscopy, scanning electron microscopy (SEM), zeta potential analysis, thermogravimetric analysis (TGA), X-ray diffraction (XRD), and attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR). The results indicated that the biosynthesized AuNPs were spherical and well-dispersed, exhibiting an absorption peak at 560 nm and an average size of 9.9 nm. Cytotoxicity assays demonstrated dose- and time-dependent inhibitory effects on MDA-MB-231, Capan-2, HCT116, and 22Rv1 cancer cell lines, with 22Rv1 and MDA-MB-231 cells showing the most potent responses. At the highest concentration tested (100 µg/mL), after 72 h, cell viability was reduced to 16.04  ±  1.8% for 22Rv1 and 17.48  ±  8.3% for MDA-MB-231 cells. Additionally, the AuNPs exhibited concentration-dependent antioxidant activity in both 2,2-diphenyl-1-picrylhydrazyl (DPPH) and hydrogen peroxide (H₂O₂) scavenging assays. In summary, the synthesized AuNPs demonstrated multifunctional properties that make them suitable for a wide range of biomedical and biotechnological applications. Full article