Search Results (1,078)

Internal insulation plasters enable historic building renovation without altering the external appearance of the wall. However, the use of internal insulation must be verified case-by-case through dynamic hygrothermal simulation, and the influence of input parameters on the results is not always clear. This paper aims to (i) characterize a new lime-based insulating plaster with expanded recycled glass and aerogel through laboratory measurements, (ii) assess the damage criteria of the plaster under different boundary conditions through dynamic simulations, and (iii) identify the most impactful design conditions on the relative humidity behind insulation. This innovative plaster combines highly insulating properties (thermal conductivity of 0.0463 W/mK) with good capillary activity while also integrating recycled components without compromising performance. The relative humidity behind insulation remains below 95% in most simulated scenarios, with cases above this threshold found only in cold climates, particularly under high internal moisture loads. The parametric study shows that (i) in the analyzed stones, the thermal conductivity variation of the existing wall has a greater effect on the relative humidity behind insulation than the variation of the vapor resistance factor, (ii) the effect of insulation thickness on the relative humidity behind insulation depends on the difference in thermal resistance of the insulation and existing masonry layers, and (iii) internal moisture load and external climate directly impact the relative humidity behind insulation. Full article

Copper and iron species were co-deposited onto a hydroxyapatite surface to produce bimetallic catalysts. Characterization techniques (XRD, XPS, DR-UV spectroscopy and TEM-EDX) helped in unveiling the speciation, nuclearity, and electronic properties of copper and iron in samples with variable total metal loading (1–10 wt.%) and relative Cu-to-Fe ratios. The speciation of Cu was revealed to be not affected by Fe and vice versa. Conversely, the metal loading turned out to be a key factor ruling the aggregation state of Cu and Fe species. The samples were tested as catalysts in the Selective Catalytic Reduction of NO by NH₃ (NH₃-SCR) in dry and wet environments under quasi-real conditions (50,000 ppm O₂; 50,000 ppm H₂O, if present; 120,000 h⁻¹ GHSV) in the 200−500 °C interval. Although the combination of Cu and Fe affords a modest improvement in water resistance compared to their monometallic counterparts, no substantial enhancement in activity was observed for the bimetallic hydroxyapatite-based SCR catalysts. Full article

This study examines the mechanical properties of concrete in which natural aggregates are entirely replaced by modified basic oxygen furnace slag (MBOFS) and reinforced with chopped carbon fibers, under both dynamic and quasi-static loading conditions. The carbon fiber (CF) was subjected to heat treatment and pneumatic dispersion prior to mixing, and its performance was validated using thermogravimetric analysis (TGA) and single-fiber tensile tests. The experimental program included tests on workability, compressive strength, flexural strength, splitting tensile strength, impact resistance, and high strain rate behavior using the reverse split Hopkinson pressure bar (RSHPB) method. Thermogravimetric analysis (TGA) and scanning electron microscope (SEM) confirmed that heat treatment removed surface sizing from carbon fibers (CF) with minimal effect on tensile strength. Replacing natural aggregates with MBOFS reduced slump but enhanced compressive, flexural, and splitting tensile strength. Incorporating 1% chopped CF further improved mechanical performance: 6 mm CF increased compressive strength, while 12 mm CF enhanced flexural and splitting tensile strength. Impact resistance improved with CF addition, with 12 mm CF slightly outperforming 6 mm. RSHPB tests showed higher dynamic strength for 6 mm CF specimens, with both strength and dynamic increase factor rising with strain rate and gas pressure. Full article

The interaction between equine hooves and various ground surfaces is a critical factor for injury prevention and performance in modern equestrian sports. Accurate measurement of surface grip is essential for evaluating the effectiveness of different hoof protection systems. This study introduces the Vienna Grip Tester (VGT), a novel sensor-based device developed to quantify rotational resistance—an important parameter for assessing hoof–surface interaction. The VGT utilizes a torque wrench and spring-loaded mechanism to simulate lateral hoof movements under a standardized vertical load (~700 N), enabling objective grip measurements across different conditions. Twenty combinations of hoof protection (barefoot, traditional iron shoe, and two glue-on models) and surfaces (sand, sand with fiber at 25 °C and −18 °C, frozen sand, and turf) were tested, yielding 305 torque measurements. Statistical analysis (repeated-measures ANOVA with Bonferroni correction) revealed significant differences in grip among surface types and hoof protection systems. Frozen surfaces (SDAF (31 ± 8.9 Nm and SDF 33 ± 8.7 Nm, p < 0.001) exhibited the highest grip, while dry sand (SDA (18.3 ± 3.3 Nm, p < 0.001) showed the lowest. Glue-on shoes (glue-on grip, 26 ± 10 Nm; glue-on, 25 ± 10 Nm) consistently provided superior grip compared to traditional or unshod hooves (bare hoof, 21 ± 7 Nm). These results validate the VGT as a reliable and practical tool for measuring hoof–surface grip, with potential applications in injury prevention, hoof protection development, and surface optimization in equestrian sports. Full article

Background: The management of triple-negative breast cancer (TNBC) remains a therapeutic challenge due to the presence of multidrug resistance (MDR) and hypoxia-induced chemoresistance, both of which substantially reduce the efficacy of conventional chemotherapy. Although certain natural compounds have shown the ability to modulate these resistance mechanisms, their clinical application is hindered by poor solubility and limited bioavailability. Among such phenolic compounds, 7-hydroxytyrosol (HTyr)—a phenolic compound from olive oil and olive leaves—has been reported to modulate hypoxia-inducible factor-1 (HIF-1). Methods: In this study, we developed hyaluronic acid (HA)-decorated solid lipid nanoparticles (SLNs) and nanostructured lipid carriers (NLCs) for the targeted and synergistic co-delivery of paclitaxel (PTX) and hydroxytyrosol carboxylic acid esters (C_n-HTyrCA), precursors that share the antioxidant biphenolic moiety with HTyr. Results: Among the formulations tested, SLNs of trilaurin (TL) exhibited the highest entrapment efficiency (EE%), optimal average particle size, Zeta potential, and good colloidal stability. Of the synthesized C_n-HTyrCA derivatives, C₈- and C₁₀-HTyrCA showed superior loading capacity. In vitro release profiles indicated a sustained drug release pattern for both nanoparticles. HA decoration led to a marked increase in particle size and induced a shift in surface charge, confirming successful decoration and suggesting enhanced targeting potential via HA-CD44 interaction. Cytotoxicity assays conducted on MDA-MB-231 cells showed that PTX-loaded TL-SLNs exerted enhanced antitumor activity, particularly when HA-decorated, and a synergistic effect was observed upon co-administration with SLNs loaded with C₈-HTyrCA. Conclusions: Overall, our findings support the potential of SLN as a promising strategy to overcome key resistance mechanisms in TNBC, enabling reduced chemotherapeutic dosing and improving therapeutic outcomes. Full article

The main goal of this work is to analyse the thermo-mechanical effect in single shear dowelled timber connections under fire conditions. This research includes the development of numerical models using the finite element method. The numerical methodology was validated using previously published experimental and numerical data. New models were developed to evaluate the temperature evolution, charring rate, and load-bearing capacity of the connections throughout exposure to fire. The calculations based on Eurocode 5 are conservative in the dimensioning of connections at room temperature but have less impact on the design of fire resistance, as they do not consider factors such as geometric parameters or passive protection influence on structural performance. Finally, based on the results obtained, two useful design equations are proposed, allowing the calculation of the load-bearing capacity of single shear timber connections, with or without protection, as a function of fire exposure. Full article

Background: HIV drug resistance (DR) mutations can compromise antiretroviral therapy (ART) success among children living with HIV (CLHIV). We conducted a secondary analysis using data from a randomized control trial for ART monitoring among CLHIV in Kisumu County, Kenya from 2019 to 2023, to assess clinical, psychosocial, and structural factors associated with HIV DR. Methods: 704 CLHIV were followed for 12+ months, with characteristics captured at enrollment and follow-up visits in the “parent” randomized-controlled-trial (of point-of-care plasma viral load testing and for viremias ≥ 1000 copies/mL HIV genotyping for DR vs. standard-of-care) and an observational “extension” substudy (of participants on a dolutegravir-containing ART with genotyping performed on viremic specimens ≥ 200 copies/mL). A multivariate modified Poisson regression model was used to analyze factors associated with sequences yielding a Stanford HIVDR database DR penalty score (DR-PS) ≥ 30 to a nucleos(t)ides and/or non-nucleoside reverse transcriptase inhibitor, protease inhibitor (PI), and/or integrase inhibitor (INSTI). Results: Among 113 (16.1%) participants who underwent genotyping, 93 (82.3%) had a DR-PS ≥ 30. DR-PS ≥ 30 were associated with age 1–5 years (adjusted risk ratio (ARR) = 1.84; 95% confidence interval (CI): 1.07, 3.14), history of viremia ≥ 1000 copies/mL (ARR = 4.18; 95% CI: 2.77, 6.31), prescription of a PI- (ARR = 6.05; 95% CI: 3.43, 10.68) or INSTI-containing regimen (ARR = 1.83; 95% CI: 1.08, 3.11), poor adherence to ART (ARR = 1.91; 95% CI: 1.32, 2.76), lack of caregiver confidence in ART administration (ARR = 1.89; 95% CI: 1.11, 3.22), and mid-sized clinic populations (ARR = 0.55; 95% CI: 0.33, 0.92). Conclusion: Addressing social factors associated with DR-PS ≥ 30 may improve ART success among CLHIV. Full article

Due to their high strength-to-weight ratio and corrosion resistance, glass fiber reinforced polymer (GFRP) composites have been used in various civil structures. However, the GFRP profiles may be perforated to allow bolting, wiring, and pipelining, causing stress concentration and safety concerns in load-carrying scenarios. A fundamental understanding of the stress concentration mechanisms and the efficacy of mitigation techniques in such anisotropic materials remains limited, particularly for the complex stress states introduced by perforations and mechanical fasteners. This study investigates the effectiveness of three techniques, adhesive filling, bolt reinforcement, and elliptical perforation design, in mitigating stress concentration and enhancing the strength of perforated GFRP plates. The effects of perforation geometry, filler modulus, bolt types, and applied preloads on the stress concentration and bearing capacity are investigated through experimental and finite element analysis. The results reveal that steel bolt reinforcement significantly improves load-bearing capacity, achieving a 13.9% increase in the pultrusion direction and restoring nearly full strength in the transverse direction (4.91 kN vs. unperforated 4.89 kN). Adhesive filling shows limited effectiveness, with minimal load improvement, while elliptical perforations exhibit the lowest performance, reducing strength by 38% compared to circular holes. Stress concentration factors (SCF) vary with hole diameter, peaking at 5.13 for 8 mm holes in the pultrusion direction, and demonstrate distinct sensitivity to filler modulus, with optimal SCF reduction observed at 30–40 GPa. The findings highlight the anisotropic nature of GFRP, emphasizing the importance of reinforcement selection based on loading direction and structural requirements. This study provides critical insights for optimizing perforated GFRP components in modular construction and other civil engineering applications. Full article

As traffic load continuously rises and climatic conditions increasingly vary, the performance of conventional base asphalt can no longer satisfy the needs of modern road engineering in low-temperature cracking resistance, high-temperature stability, and long-term durability. Therefore, the development of novel and efficient asphalt modifiers holds significant engineering value and practical importance. In this study, modified asphalt was prepared using varying dosages of ZM modifier (direct-injection asphalt mixture modified polymer additive). A series of experiments was executed to assess its influence on asphalt properties. First, fundamental property tests were implemented to determine the regulating effect of the ZM modifier on basic physical performances, like the softening point and penetration of the base asphalt. Penetration tests at different temperatures were performed to calculate the penetration index, thereby assessing the material’s temperature sensitivity. Subsequently, focusing on temperature as a key factor, tests on temperature sweep, and multiple stress creep recovery (MSCR) were implemented to delve into the deformation resistance and creep recovery behavior of the modified asphalt under high-temperature conditions. In addition, bending beam rheometer (BBR) experiments were introduced to attain stiffness modulus and creep rate indices, which were applied to appraise the low-temperature rheological performance. Aside from Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FTIR) was utilized to explore the mechanism by which the ZM modifier influences the asphalt’s functional group composition and microstructure. Our findings reveal that the ZM modifier significantly increases the asphalt’s softening point and penetration index, reduces penetration and temperature sensitivity, and enhances high-temperature stability. Under high-temperature conditions, the ZM modifier adjusts the viscoelastic balance of asphalt, hence enhancing its resistance to flow deformation and its capacity for creep recovery. In low-temperature environments, the modifier increases the stiffness modulus of asphalt and improves its crack resistance. FTIR analyses reveal that the ZM modifier does not introduce new functional groups, indicating a physical modification process. However, by enhancing the cross-linked structure and increasing the hydrocarbon content within the asphalt, it strengthens the adhesion between the asphalt and aggregates. Overall, the asphalt’s performance improvement positively relates to the dosage of the ZM modifier, providing both theoretical basis and experimental support for its application in road engineering. Full article

Stirling engines are widely applied due to their high thermal efficiency and ability to operate with diverse heat sources. An accurate thermodynamic model is essential for optimising engine design parameters and evaluating the thermal performance of Stirling engines. Despite the fact that the Schmidt model and the ideal adiabatic model quite commonly approximate the performance, they frequently neglect critical loss mechanisms such as regenerator inefficiency, flow resistance, and mechanical friction. In order to address the limitations identified, this study proposes a numerical performance analysis of the GENOA 03 α-type Stirling engine under real operating conditions. The analysis is conducted using an extended second-order Simple Model and Finite Speed approach. The model incorporates significant irreversibilities, including the effectiveness of the regenerator, pressure losses, the shuttle effect, and mechanical friction. A novel aspect of this study is the experimental determination of mechanical friction losses under no-load conditions at various rotational speeds, which are then integrated into the numerical model. The findings of the study indicate that regenerator imperfection and friction losses are significant factors affecting the performance of Stirling engines, and contribute approximately 23% and 14% of the total engine inefficiency, respectively. The model also identifies 1.25 MPa as the minimum operational pressure threshold. The proposed approach integrates experimental data with modified analytical modelling providing more accurate performance predictions for Stirling engines. Full article

Ensuring the long-term electro-mechanical reliability of high-voltage alternating current (HVAC) insulator strings requires a detailed understanding of how multiple environmental and electrical stressors influence the corrosion behavior of hot-dip galvanized steel fittings. In this study, a three-factor, three-level L9(3³) orthogonal accelerated corrosion test was conducted to systematically evaluate the individual and interactive effects of marine salt deposition (0–10 g m⁻² day⁻¹), acetic acid pollution (0–8 µg m⁻³), and 50 Hz AC leakage current (0–10 mA) on miniature pin-type assemblies. A comprehensive post-corrosion characterization approach was employed. The results revealed that chloride loading from salt deposition was the dominant contributor to corrosion. However, the synergistic interaction between salt and leakage current led to an acceleration in zinc depletion compared to the additive effect of the individual factors. A quadratic regression model with a high correlation coefficient was developed to predict corrosion volume per unit area. The findings offer a mechanistic explanation for field-reported failures in coastal power grids and provide actionable guidance for optimizing corrosion-resistant coatings and implementing electrical mitigation strategies. Full article

The mechanical and structural design of railway vehicles is heavily influenced by their lifetime. Because fatigue is a significant factor that impacts the longevity of railway components, it is imperative that the fatigue resistance properties of crucial components, like leaf springs, be thoroughly investigated. This research investigates the fatigue resistance of 51CrV4 steel under bending and axial tension, considering different stress ratios across low-cycle fatigue (LCF), high-cycle fatigue (HCF), and very-high-cycle fatigue (VHCF) regimes, using experimental data collected from this work and prior research. Data included fractographic analyses aiming to help in understanding some of failures for different loads. The presence of geometric discontinuities, such as notches, amplifies stress concentrations, requiring a probabilistic approach to fatigue assessment. To address notch effects, the theory of critical distances (TCD) was employed to evaluate fatigue strength. TCD model was integrated in fatigue statistical models, such as the Walker model (WSN) and the Castillo–Fernández-Cantelli model adapted for mean stress effects (ACFC). Extending the application of the TCD theory, this research provides an improved probabilistic fatigue model that integrates notch sensitivity, mean stress effects, and fatigue regimes, contributing to more reliable design approaches of railway leaf springs or other components produced in 51CrV4 steel. Full article

Complete dentures (CD) are prone to biofilm formation, particularly by Candida species, which may lead to denture stomatitis (DS). As edentulism remains highly prevalent among the global ageing population, denture-related infections represent a significant public health concern. The novelty of this study lies in integrating the clinical severity of DS with the prevalence, microbial load, and antifungal susceptibility profile of Candida spp., providing new insights into the pathogenesis and therapeutic management of this condition. Biofilm from the CD and palate was seeded for prevalence and microbial load. The identification of strains was confirmed molecularly, and susceptibility to micafungin, nystatin, fluconazole, and miconazole was assessed by the broth microdilution method. Prevalence was shown in percentage, microbial load was analyzed using a generalized linear model test, and susceptibility was assessed using Pearson’s Chi-square test (p < 0.05). Candida albicans was the most prevalent regardless of DS. However, a higher microbial load of C. albicans was observed with increased severity of DS (p = 0.038). Except for Candida tropicalis, the microbial load of the CD was higher than that of the palate. C. tropicalis showed resistance to fluconazole with increased severity of DS (p = 0.004). All strains were susceptible to nystatin and miconazole, and three were resistant to micafungin. The findings suggest that the prevalence of Candida spp. is not a determining factor in the variation in DS severity. Nevertheless, patients with severe inflammation harbor an increased load of C. albicans on both sites. Nystatin and miconazole appear to be effective treatments for DS. Full article

Background: Medicago ruthenica, a perennial legume forage valuable for ecological restoration and improved breeding, suffers significant harvest losses due to pod shattering. Pod shattering is a trait not only linked to not only pod ventral suture, but also pericarp properties. In this study, we aimed to (1) elucidate the role of pericarp in explosive pod shattering by comparing shattering-susceptible (SPD) and shattering-resistant (RPD) M. ruthenica genotypes, and (2) identify key regulatory genes and pathways underlying this mechanism. Methods: We conducted comparative analyses of pericarp anatomy and physiological traits (pericarp components such as water content, cellulose, hemicellulose, pectin, and lignin; and the activities of enzymes such as cellulose synthase A (CesA), phenylalanine ammonia-lyase (PAL), 4-coumarate: CoA ligase (4CL), cinnamyl alcohol dehydrogenase (CAD), and peroxidase (POD) in SPD and RPD pods). Transcriptome of pod pericarps identified differentially expressed genes (DEGs) for the selection of candidates functional genes. Promoter analysis was performed on candidate functional genes to identify specific regulated factors. The functional role of auxin signaling was validated through exogenous auxin application and the assessment of pod shattering rates and gene expression. Results: SPD pod pericarps exhibited significantly higher lignification of endocarp, lignin, cellulose, hemicellulose and pectin content, but lower water content than RPD. Principal component analysis identified that lignin contributes the highest loading value (0.727) contributor to pod shattering. The activities of five cell wall biosynthesis enzymes were higher in SPD pod pericarps than RPD. Transcriptome analysis identified more than 3419 DEGs in SPD pericarps. KEGG enrichment highlighted “phenylpropanoid biosynthesis” as the most significant pathway. A total of 57 lignin-biosynthesis-related DEGs were upregulated in SPD, including 15 PODs. Promoters of 11 POD genes contained MYB-binding motifs and 8 contained auxin-responsive elements, a total of 76 MYB transcription factors (mostly upregulated) and 9 auxin biosynthesis genes (mostly downregulated) were differentially expressed in SPD. Exogenous auxin application significantly reduced SPD pod shattering to 23.6% and concurrently downregulated PODs expression. Conclusions: This study establishes that enhanced lignification within the pericarp endocarp by the upregulation of lignin biosynthetic genes (particularly PODs), coupled with upregulation by MYB transcription factors and downregulation by auxin, is a core mechanism of explosive pod shattering in M. ruthenica. The identified DEGs, especially MYBs, PODs, and auxin pathway genes, provide gene information for breeding shattering-resistant M. ruthenica varieties through molecular design or marker-assisted selection. Full article

Laminated glass (LG) composite systems are increasingly being utilized in architectural and security applications due to their enhanced strength and safety features. Understanding the structural response of LG systems is crucial for optimizing their performance under blast loads. This paper presents a comprehensive study of an analytical model for predicting the static and dynamic resistance functions of various LG systems used in blast-resistant designs to advance engineering analysis and design methods. The proposed analytical model integrates the strain-rate-dependent interlayer behavior with the glass dynamic increase factors to generate a physically consistent post-fracture membrane resistance, offering a unified framework for deriving the static and dynamic resistance functions directly applicable to single-degree-of-freedom (SDOF) analyses across different LG layups. The developed models were validated statistically using full-scale water chamber results and dynamically against experimental blast field data and the results from shock tube testing. We validated the model’s accuracy for various LG layup configurations, including variations in the glass and interlayer sizes, types, and thicknesses. The established dynamic resistance model was developed by incorporating a strain-rate-dependent interlayer material model. The energy absorption of LG panels, influenced by factors like interlayer thickness and type, is critical for blast design, as it determines the panels’ ability to withstand and dissipate energy, thereby reducing the transmitted forces and deformations to a building’s structure. The dynamic model closely matched the dynamic deflection time histories, with a maximum difference of 6% for all the blast experiments. The static resistance validations across the various LG configurations consistently demonstrated reliable prediction results. The energy absorption comparisons between the analytical and quasi-static LG panel responses ranged from 1% to 17%. These advancements provide higher-fidelity SDOF predictions and clear guidance for selecting the interlayer type and thickness to optimize energy absorption. This will result in enhanced blast resistance and contribute to more effective blast mitigation in glazing system design. Full article