Search Results (403)

The Qingshan lead–zinc (Pb–Zn) deposit in northwestern Guizhou Province is a structurally controlled, carbonate-hosted system formed from basin-derived hydrothermal processes. Geology, fluid inclusion, and isotopic data reveal a multi-stage hydrothermal circulation after Emeishan Large Igneous Province (ELIP, ~260 Ma) tectono-thermal reactivation within the Sichuan–Yunnan–Guizhu triangle (SYGT) area. Fluid inclusion microthermometry indicates that ore-forming fluids were derived from deep sources influenced by enhanced crustal heat flow linked with possible thermal input from Indo-Caledonian tectonic activity after ELIP. Ore-stage calcite records mixed carbon derived from marine carbonates with additional inputs from organic matter and deep-sourced fluids, reflecting carbonate dissolution and fluid–rock interaction. Sulfide, together with fluid inclusion temperatures > 120 °C, indicates sulfur derived from evaporitic sulfate reduced by thermochemical sulfate reduction (TSR); the heavy sulfur signature and partial isotopic disequilibrium among coexisting sulfides reflect dynamic fluid mixing during ore deposition. Lead isotopes indicate metallogenic metals were leached mainly from Devonian–Permian carbonates with subordinate basement input. Ore precipitated by cooling, depressurization, and mixing of metal-rich, H₂S-bearing fluids in structurally confined zones where the carbonate–clastic interface effectively trapped ore-forming fluids, producing high-grade sphalerite–galena mineralization. Collectively, these data support a Huize-type (HZT) carbonate-hosted Pb–Zn genetic model for the Qingshan deposit. Full article

The growing use of reclaimed asphalt pavement (RAP) in warm-mix asphalt (WMA) presents significant challenges when RAP originates from aged polymer-modified binder (PMB) pavements, where severe oxidation and polymer degradation lead to excessive stiffness and poor cracking resistance. This study presents a multi-scale evaluation of a hybrid modification strategy combining recycled engine oil waste (REOW, 3 wt.%) and styrene–butadiene–styrene (SBS, 1–4 wt.%) to restore aged PMB-containing RAP systems under controlled binder conditions. Three binders (control, REOW-modified, and REOW–SBS hybrid) were prepared using a fixed 70/30 virgin-to-RAP binder blend and characterized through rheological analysis, and multiple stress creep recovery (MSCR). The findings show that REOW softened the binder but reduced elastic recovery, whereas SBS modification restored elastic response. Corresponding WMA mixtures with 30 wt.% RAP and 5.0 wt.% total binder content were evaluated for moisture damage, raveling, rutting, and cracking resistance. At the mixture scale, the hybrid system achieved a TSR of 83%, reduced Hamburg rut depth by ~20%, and increased SCB fracture energy by ~30% compared with the control. These findings demonstrate that combined rejuvenation–reinforcement effectively re-mobilizes aged PMB chemistry and restores polymer elasticity, enabling high-performance WMA production with RAP derived from polymer-modified pavements. Full article

This paper presents a numerical study of fluid–structure interaction (FSI) applied to wind turbines, combining computational fluid dynamics (CFD) and finite element analysis (FEA). The study focuses on a 3D wind turbine blade inspired by the GE 1.5XLE model. The blade features a twisted geometry with S818, S825, and S826 aerodynamic profiles, and is made of an orthotropic composite material with variable thickness and an internal spar. The fluid domain is defined by two circular sections upstream and downstream, aligned along the Z-axis. Simulations are performed under a wind speed of 12 m/s and a rotational speed of −2.22 rad/s (Tip Speed Ratio (TSR) = 8), with air modeled as an incompressible fluid at ambient temperature. On the CFD side, a periodic and symmetric modeling approach is applied, reducing the fluid domain to one-third of the full configuration by simulating flow around a single blade and extrapolating results to the remaining ones. This method achieves a 47% reduction in computation time while maintaining high accuracy in aerodynamic results. On the FEA side, spar condensation is performed by creating a superelement using the substructuring method. This strategy reduces structural computation time by 45% while preserving reliable predictions of displacements, stresses, and natural frequencies. These results confirm the effectiveness of the proposed techniques for accurate and computationally efficient aeroelastic simulations. Full article

This study presents the development and experimental validation of a novel wind turbine emulator (WTE) based on a doubly fed induction generator (DFIG). The proposed architecture employs an induction motor (IM) driven by a variable frequency drive (VFD) to emulate wind turbine dynamics, offering a cost-effective and low-maintenance alternative to traditional DC motor-based systems. The contribution of this work lies, therefore, not in the hardware topology itself, but in the complete real-time software implementation of the control system using C language and RTLib, which enables higher sampling rates, faster PWM updates, and improved execution reliability compared with standard Simulink/RTI approaches. The proposed control structure integrates tip–speed ratio (TSR)-based maximum power point tracking (MPPT) with flux-oriented vector control of the DFIG, fully coded in C to provide optimized real-time performance. Experimental results confirm the emulator’s ability to accurately replicate real wind turbine behavior under varying wind conditions. The test bench demonstrates fast dynamic response, with rotor currents settling in 11–18 ms, and active/reactive powers stabilizing within 25–30 ms. Overshoots remain below 10%, and steady-state errors are limited to ±1 A for currents and ±100 W/±50 VAR for powers, ensuring precise power regulation. The speed tracking error is approximately 0.61 rad/s, validating the system’s ability to follow dynamic references with high accuracy. Additionally, effective decoupling between active and reactive loops is achieved, with minimal cross-coupling during step changes. Full article

This study investigates the relationship between investor sentiment (IS) and trust in sustainability reports (TSRs) in Egypt, which is an emerging market that has recently strengthened its sustainability disclosure practices. Drawing on behavioral finance and disclosure theory, this study also examines the moderating role of financial literacy (FL) in shaping this relationship. A quantitative, questionnaire-based survey was presented to 328 individual investors who are familiar with sustainability and ESG reporting. The data were analyzed using descriptive statistics, reliability tests, and both simple and hierarchical regression analysis. The results indicate that IS has a strong and significant positive effect on trust in sustainability reports, with market optimism and emotional influence emerging as the most influential dimensions. Furthermore, the hierarchical regression results reveal that FL significantly strengthens the relationship between IS and TSR, indicating that, within the present sample, more financially literate investors translate sentiment into more informed and rational trust judgments. These findings contribute to the accounting and sustainability reporting in the literature by demonstrating that trust in non-financial disclosures is not only shaped by reporting practices but is also heavily influenced by investor psychology and financial competence. This study highlights the importance of enhancing both disclosure quality and investor financial literacy to strengthen confidence in sustainability reporting in emerging markets. Full article

Climate change presents a major challenge of the Anthropocene, with construction activities contributing about 23% of global CO₂ emissions. Pavement engineering, particularly hot mix asphalt (HMA) production, generates roughly 350 million tons of CO₂ annually due to high-temperature processes. Cold mix asphalt (CMA) has emerged as a sustainable alternative, reducing energy use by 35–50% and emissions by 40–60% through ambient-temperature production with emulsified or cutback binders. Although early CMA formulations suffered from low mechanical strength, long curing times, and poor moisture resistance, recent innovations such as nano-modified binders, polymer and rubber additives, and optimized RAP utilization have greatly improved performance. Modern CMA now achieves enhanced rutting resistance (>4000 cycles/mm), moisture resistance (TSR > 85%), and rapid strength gain (24 h). This review synthesizes findings from over 160 studies to examine composition, property relationships, performance evaluation methods, life-cycle comparisons, and global field validations. Furthermore, it highlights gaps in predictive modeling, mix-design standardization, and circular economy integration to support the evolution of next-generation CMA technologies aligned with UN Sustainable Development Goals 9, 11, and 13. Full article

Stone Mastic Asphalt (SMA) mixtures exhibit superior performance under traffic loads due to the high content of coarse aggregates; however, the high bitumen content also leads to the problem of bitumen drainage from the mixture. Several studies have been conducted on the use of stabilizing additives such as fibers, polymers, or mineral fillers to reduce binder drainage in SMA mixtures. In this study, however, an innovative and sustainable solution was developed to address the bitumen drainage problem encountered in SMA pavements and to improve the long-term performance of the mixture. In this context, the feasibility of using cellulose acetate (SG) material recycled from cigarette butts as an alternative fiber additive to the traditionally used cellulose fiber (SL) was investigated. This method aims to achieve both environmental benefits in terms of waste management and economic advantages in terms of additive materials. Additionally, the effect of using different SL contents (0.1%, 0.2%, 0.3%, 0.4%, 0.5%) on mixture performance was examined. Within this scope, both pure bitumen (B) and Elvaloy RET + PPA (E)-modified bitumen (1.6%, 1.7%, and 1.8% Elvaloy RET + 0.2% PPA) were used to produce both fiber-reinforced and non-fiber-reinforced SMA mixtures. Traditional and Superpave tests were conducted to determine the rheological and physical properties of the pure and modified binders. All SMA specimens were tested for Marshall stability and flow, Marshall quotient, indirect tensile strength (ITS), tensile strength ratio (TSR), Schellenberg bitumen drainage, sand patch, and Cantabro particle loss. Furthermore, a cost analysis was carried out to evaluate the economic effect of different fiber types and proportions. Among the SMA mixtures, the highest stability and resistance to moisture damage were achieved in the mixtures containing 1.6% Elvaloy RET + 0.2% PPA with 0.3–0.4% SG and 1.7% Elvaloy RET + 0.2% PPA with 0.3–0.4% SL, while the optimum surface texture depth was obtained in the mixtures containing 1.6–1.7% Elvaloy RET + 0.2% PPA with 0.3% SG. In conclusion, the Elvaloy RET + PPA modification enhanced the aging resistance of the bitumen, while the SG fibers used at 0.3–0.4% fiber content in the 1.6–1.7% Elvaloy RET + 0.2% PPA-modified series were identified as a promising mechanical and economic alternative to conventional SL fibers. Full article

We present a coupled large-eddy simulation (LES) and bed morpho-dynamics study to investigate the influence of sediment dynamics on the performance of a utility-scale marine hydrokinetic vertical-axis turbine (VAT) parametrized by an actuator surface model. By resolving the interactions between turbine-induced flow structures and bed evolution, this study offers insights into the environmental implications of VAT deployment in riverine and marine settings. A range of tip speed ratios is examined to evaluate wake recovery, power production, and bed response. The actuator surface method (ASM) is implemented to capture the effects of rotating vertical blades on the flow, while the immersed boundary method accounts for fluid interactions with the channel walls and sediment layer. The results show that higher TSRs intensify turbulence, accelerate wake recovery over rigid beds, and enhance erosion and deposition patterns beneath and downstream of the turbine under live-bed conditions. Bed deformation under live-bed conditions induces asymmetrical wake structures through jet flows, further accelerating wake recovery and decreasing turbine performance by about 2%, compared to rigid-bed conditions. Considering the computational cost of the ASM framework, which is nearly 4% of the turbine-resolving approach, it provides an efficient yet robust tool for assessing flow–sediment–turbine interactions. Full article

Flexible pavements using conventional bitumen are prone to suffering severe distress in hot climates, particularly rutting and moisture-induced damage. This study explores synergistic effects of waste-derived High-Density Polyethylene (HDPE) and Bakelite as dual modifiers for asphalt mixtures under Pakistan’s extreme climate, where summer temperatures exceed 45 °C. Modified mixtures were prepared via wet process using HDPE (3%, 6%, 9% by weight of optimum bitumen content) combined with 6% Bakelite, evaluated against control mixtures (60/70 bitumen, NHA Class-B gradation). Performance assessment included indirect tensile strength, moisture susceptibility (TSR), resilient modulus, and Hamburg wheel tracking tests. The optimal 6%HDPE + 6%Bakelite formulation achieved remarkable improvements over control: 24.7% higher dry ITS (0.647 MPa), 48.7% higher conditioned ITS (0.617 MPa), 95.36% TSR (19% above specifications), 43.7% greater resilient modulus (4866 MPa), and 27.4% lower rutting depth (2.38 mm). These enhancements are likely associated with the development of a stiffer polymer resin network between HDPE and rigid Bakelite particles, which appears to provide a favorable balance between mixture flexibility and stiffness. At 9% HDPE, performance degradation in strength and moisture-related properties suggests possible phase separation, although rutting resistance continued improving. This dual-modification strategy provides sustainable, cost-effective enhancement of pavement durability in hot climates while addressing waste management challenges, offering significant potential for reducing maintenance costs and extending service life. Full article

The ongoing launch of high-resolution satellites has led to a significant increase in the volume of synthetic aperture radar data, resulting in a high-resolution and high-revisit Earth observation that efficiently supports subsequent high-resolution SAR change detection. To address the issues of speckle noise interference, insufficient integrity of change targets and blurred boundary location of high-resolution SAR change detection, we propose a coarse-to-fine framework based on the multi-scale segmentation and hybrid structure graph (HSG), which consists of three modules: multi-scale segmentation, difference measurement, and change refinement. First, we propose a graph-based multi-resolution co-segmentation (GMRCS) in the multi-scale segmentation module to generate hierarchically nested superpixel masks. And, a two-stage ranking (TSR) strategy is designed to help GMRCS better approximate the target edges and preserve the spatio-temporal structure of changed regions. Then, we introduce a graph model and measuring difference level based on the HSG. The multi-scale difference image (DI) is generated by constructing the HSG for bi-temporal SAR images and comparing the consistency of the HSGs to reduce the effect of speckle noise. Finally, the coarse-scale change information is gradually mapped to the fine-scale based on the multi-scale fusion refinement (FR) strategy, and we can get the binary change map (BCM). Experimental results on three high-resolution SAR change detection datasets demonstrates the superiority of our proposed algorithm in preserving the integrity and structural precision of change targets compared with several state-of-the-art methods. Full article

This study presents a comprehensive numerical and theoretical analysis comparing the aerodynamic performance of a racetrack trajectory vertical axis wind turbine with a baseline VAWT. The racetrack trajectory comprises two parallel straight segments connected by semicircular arcs. However, two critical research gaps remain: the aerodynamic performance of this non-axisymmetric rotor, especially its sensitivity to inflow direction, is not well understood, and a computationally efficient theoretical model for its rapid design is lacking. Using unsteady Reynolds-Averaged Navier–Stokes (URANS) simulations to systematically quantify this sensitivity, and developing an adapted double multiple streamtube (DMST) model, the performance of both turbines is evaluated across tip speed ratios (TSRs) of 1.5–4 and inflow angles β = 0–90°. Results indicate that the racetrack turbine achieves a peak power coefficient of 0.49 at TSR = 2.5 and β = 90°, 16.7% higher than the baseline VAWT. Its performance is highly sensitive to inflow direction, whereas the baseline operates more uniformly across angles. Flow field and wake analyses reveal that the racetrack turbine exhibits faster wake recovery and lower turbulence intensity downstream under optimal inflow. This study demonstrates the potential of racetrack turbines for enhanced directional efficiency in marine wind conditions and validates the adapted DMST model as a reliable tool for preliminary design. Full article

Sustainable management of Construction and Demolition Waste (CDW) is key to the Circular Economy. Reusing crushed concrete as recycled concrete aggregates (RCAs) in hot-mix asphalt (HMA) is a viable CDW solution, although RCA’s high absorption can affect performance. This study evaluates the effect of partially replacing 0%, 10%, and 30% of virgin aggregate with RCA in a dense-graded HMA, assessing its moisture susceptibility and cracking resistance. Specimens were subjected to long-term water-immersion aging (3 and 6 months at 25 °C) and tested for Indirect Tensile Strength (ITS), Tensile Strength Ratio (TSR), and Cracking Tolerance Index (CT-index). RCA incorporation consistently increased ITS at all aging levels. In particular, the 30% RCA mixtures exhibited the highest strength, exceeding the absolute ITS thresholds required by various U.S. transportation agencies to ensure structural capacity. While TSR values remained below the 80% AASHTO T 283 threshold, 10% and 30% RCA mixes had higher TSR than the control, indicating a comparative improvement in moisture resistance. Conversely, the CT-index decreased with more RCA and longer immersion, particularly at 30% RCA, revealing a trade-off between strength gain and cracking tolerance under prolonged wet exposure. Overall, a 10% RCA replacement level provided the most balanced performance, supporting its technical feasibility for sustainable, performance-based mixture design. Full article

A new approach for optimizing the blade profile of a horizontal axis wind turbine is proposed in this paper, based on the combination of the Blade Element Momentum (BEM) method and Proper Generalized Decomposition (PGD). The resulting algorithm was implemented in MATLAB (R2010A). To investigate the applicability of the proposed BEM-PGD method, simulations were conducted using the NREL phase VI turbine. By focusing on the tangential force coefficient as a parametrized solution, the study demonstrated a 21.7% improvement in the power coefficient relative to the baseline blade corresponding to a 20 kW turbine, while the tip speed ratio (TSR) ranged from 1 to 12, as assessed through a quantitative metric comparing the optimized and reference curves. These advancements are attributed to the algorithm’s capability to parameterize the solution and to select the appropriate airfoil type, thickness, chord, and twist, allowing for an optimized and realistic blade design. Full article

Protein kinase CK2 is an important regulator of cell, embryo, and organism function whose transcript levels are often dysregulated in disease. Previous studies have primarily focused on the regulation of CK2 gene expression via the proximal promoter. Here, we analyzed the core promoter of the CK2 genes and pseudogene to assess the structure and potential regulatory elements. Our analysis showed that CSNK2A1 contained 14 exons, rather than 13 exons as previously reported. Using FANTOM5 and DBTTS data, we found that transcription start sites were broadly distributed across a 100-nucleotide region in the CK2 gene core promoters, consistent with “broad” class promoter architecture. Using these databases, we found a dissimilar transcription start site usage between adult and cancer tissues compared to fetal tissues for each of the CK2 gene promoters. A further analysis of the CK2 gene core promoter subregions showed instances of core promoter subregion switching. All CK2 gene core promoters contained canonical and non-canonical initiator motifs, suggesting their potential as dual-initiator core promoters, while CSNK2A3 only had canonical initiator motifs. Additionally, all CK2 gene core promoters contain DCE motifs and pause buttons. In contrast, Wnt/β-catenin target genes c-MYC and CCND1 had DPEs, which can be regulated by protein kinase CK2. Collectively, our data provides new insights into the transcriptional regulation of CK2 genes and opens new avenues for research. Full article

To investigate the long-term water stability of graphene-modified permeable asphalt mixtures, in this study, we analysed the effects of single factors and multi-factor coupling. The single-factor water stability was investigated through the free thawing splitting test, standard Cantabro test, and immersion Cantabro test; the experimental indicators were the freeze–thaw cracking ratio (TSR), mass loss rate, and immersion mass loss rate, respectively. The multi-factor water stability was studied through immersion operation tests of mixtures with different degrees of ageing. The dispersion of graphene was examined through Raman mapping, the formation of three-dimensional network structures of graphene and SBS was evaluated via the dynamic shear rheometer test (DSR), and the elemental distribution was quantitatively analysed using energy-dispersive spectroscopy (EDS) and an image pixel algorithm (RGB). The results indicate that an unaged graphene-composite- and SBS-modified permeable asphalt mixture with an optimal graphene content of 0.05% demonstrated a 4.5% improvement in the TSR, alongside reductions in the mass loss rate and water immersion mass loss rate of 25.64% and 23.52%, respectively. Even after prolonged thermal oxygen ageing, its TSR, mass loss rate, and water immersion mass loss rate improved by 5.1%, 23.04%, and 20.70%, respectively. Multi-factor coupling tests confirmed that the water stability met requirements under severe conditions, with better performance at high temperatures. Graphene was uniformly dispersed in the modified asphalt. The appearance of a plateau region at low frequencies in graphene-composite- and SBS-modified asphalt verified the formation of a three-dimensional network structure, and the oxygen content was positively correlated with deepening thermal oxidative ageing. Full article