Search Results (125)

Pavement macrotexture, quantified by mean texture depth (MTD) and mean profile depth (MPD), is a critical parameter for road safety and performance. The traditional sand patch test is labor-intensive and slow, creating a bottleneck for modern pavement management systems. Accurately translating the rich point cloud data into reliable MTD values using the 3D scanning method remains a challenge, with current methods often relying on oversimplified correlations. This research addresses this gap by developing and validating a novel machine learning framework to predict MTD and MPD directly from high-resolution 3D laser scans. A comprehensive dataset of 127 pavement samples was created, combining traditional sand patch measurements with detailed 3D point clouds. From these point clouds, 27 distinct surface features spanning statistical, spatial, spectral, and geometric domains were developed. Six machine learning algorithms, consisting of Random Forest, Gradient Boosting, Support Vector Regression, k-Nearest Neighbor, Artificial Neural Networks, and Linear Regression, were implemented. The results demonstrate that the ensemble-based Random Forest model achieved superior performance, predicting MTD with an R² of 0.941 and a mean absolute error (MAE) of 0.067 mm, representing a 56% improvement in accuracy over traditional digital correlation methods. Model interpretation via SHAP analysis identified root mean square height (Sq) and surface skewness (Ssk) as the most influential features. Full article

The fluctuating nature of renewable energy sources such as wind and solar power poses significant challenges to the stability of power grids, while pumped-storage hydropower, with its advantages in peak regulation and frequency control, has become an essential component of modern energy strategies. However, sediment in rivers adversely affects the operational efficiency and stability of PSH units, leading to accelerated wear and shortened service life. In this study, the low-pressure stage of a two-stage pump turbine was selected as the research object, and the Euler–Euler numerical method was employed to investigate the solid–liquid two-phase flow characteristics of the pump turbine in pump mode. The results show that, compared with the clear-water condition, the head and efficiency decrease by up to 7.9% and 15%, respectively, after the addition of sand particles. The average pressure within the flow-passage components increases, while the streamlines become more non-uniform, accompanied by the formation of vortices and backflow in the guide and return vanes. The total entropy generation increases with rising particle concentration but decreases with larger particle size. Among the components, the high-entropy regions are mainly located on the suction surface and trailing edges of the impeller blades, the inlet and blade surfaces of the guide vanes, and the inlet and trailing edges of the return vanes. Moreover, the pressure pulsation amplitudes at monitoring points in the vaneless region, guide vane–return vane interaction region, and leading edge of the return vane increase progressively with both particle size and concentration. The dominant and secondary frequencies at all monitoring points correspond to the blade-passing frequency (BPF) and its harmonics, indicating that rotor–stator interaction is the principal cause of pressure pulsations under pump operating conditions. Full article

The research empirically evaluates ancient earth construction techniques through the analysis of archaeological adobe samples from Tell Zurghul/Nigin, south-eastern Iraq, dating from the mid-5th to mid-3rd millennium BCE. Simple, non-standardised empirical field tests were employed to obtain preliminary material characterisations, valuable for pilot assessments and gaining further significance when compared with quantitative analytical results. Their application evaluates the functionality of these tests while integrating archaeological insights with material science, underscoring the importance of multidisciplinary collaboration in earthen heritage conservation. Sixteen samples—fifteen archaeological and one modern—were analysed to assess raw material composition, grain size, clay behaviour, organic content, cohesion in wet and dry states, and surface adhesion. Results demonstrate notable homogeneity in material composition across the time span, primarily fine sands with minimal clay or silt. This suggests favourable drainage, minimal shrinkage, and reduced cracking but limited cohesion, implying a potential need for stabilisers such as plastic clays or fibres in construction. These findings inform conservative strategies for the preservation and restoration of earthen structures at the site. Full article

This study presents a forensic investigation of the catastrophic failure of the La Luciana Tailings Storage Facility (TSF) in Reocín, Spain, in 1960. The collapse released approximately 300,000 m³ of tailings, causing 18 fatalities, extensive flooding of farmland and lakes, and the contamination of the Besaya River, leading to long-term environmental degradation. The analysis integrates historical documentation, cartographic evidence, in situ testing, laboratory analyses, and numerical modelling to reconstruct the failure sequence and identify its causes. Geotechnical characterization based on cone penetration tests (CPTs), shear wave velocity profiles, and laboratory testing revealed pronounced heterogeneity, with alternating contractive and dilative layers. Hydraulic analyses indicate permeabilities from 10⁻⁵ m/s in sand dam materials to 10⁻⁹ m/s in fine-grained pond deposits, with evidence of capillary saturation exceeding 20 m, favouring excess pore-pressure accumulation. Limited equilibrium and finite element analyses show that when the decant pond was within ~20 m of the dam, the factor of safety dropped to unity, triggering retrogressive flowslides consistent with field evidence. The results underline critical lessons for TSF governance: maintaining unsaturated tailings, ensuring efficient drainage and decant systems, and monitoring pond proximity to the dam. These are essential to prevent flow failures. This research also demonstrates a replicable forensic methodology applicable to other historical TSF failures, enhancing predictive models and informing modern frameworks such as the EU Directive 2006/21/EC and the Global Industry Standard on Tailings Management (GISTM). Full article

To address limitations such as cleaning difficulties or secondary contamination/damage of cultural relics caused by the uncontrollable diffusion of water/cleaning agent/dirty liquids during the cleaning process in traditional cleaning methods, this study, using cotton textiles as an example, systematically investigated the cleaning efficacy of four in situ methods (blank gel, cleaning gel, ultrasonic emulsification, and gel + ultrasonic emulsification synergistic cleaning) on eight types of stains, including sand, clay, rust, blood, ink, oil, and mixed solid/liquid stains. Building upon this, this study proposed an efficient, targeted, in situ, and controllable cleaning strategy tailored for fragile, stained textile relics. Results demonstrated that, regardless of the stain type, the synergistic cleaning method of G+U (gel poultice + ultrasonic emulsification) consistently outperformed the cleaning methods of blank gel poultice, cleaning gel poultice, and ultrasonic emulsification. Furthermore, the gel loaded with cleaning agents was always more effective than the blank gel (unloaded cleaning agents). The poultice methods of blank gel and cleaning gel were better suited for solid stains, while the ultrasonic emulsification cleaning method was more effective for liquid stains. Meanwhile, it was also found that the optimal cleaning method proposed in this study (the G+U synergistic cleaning method) was a cleaning method that restricted the cleaning agent within the gel network/emulsion system, and utilized the porous network physical structure of gel, the chemical action of emulsion’s wetting/dissolving dirt, and the cavitation synergistic effect of ultrasound to achieve the targeted removal of contaminants from relics’ surfaces. Crucially, the cleaning process of G+U also had the characteristics of controlling the cleaning area at the designated position and effectively regulating the diffusion rate of the cleaning solution within the treatment zone, as well as the reaction intensity. Therefore, the proposed optimal (the synergistic cleaning method of G+U) cleaning method conforms to the significant implementation of the “minimal intervention and maximal preservation” principle in modern cultural heritage conservation. Consequently, the synergistic cleaning method of G+U holds promise for practical application in artifact cleaning work. Full article

To address the challenges of characterizing commingled production from multiple channel sand layers with varying boundaries and shapes in tight gas reservoirs, a novel Rate Transient Analysis (RTA) model was established based on the principle of equivalent seepage volume (ESV). This model enables the determination of boundary sizes and permeabilities of individual channel sand layers within commingled tight reservoirs using modern production decline analysis theory. The production decline behavior under different channel sizes, numbers, and configurations was systematically investigated through type curve analysis. The results reveal the existence of five distinct stages in the production decline curves for unequal-width channel sands. The intermediate transient flow stage serves as a diagnostic indicator for identifying boundary disparities among layers. Furthermore, reservoirs with smaller boundary distances, fewer wide channel sand layers, and lower thickness proportions of wider channels exhibit poorer productivity and tend to experience accelerated production decline during early and middle transient flow stages. The proposed method provides an effective approach for characterizing boundary parameters of commingled tight reservoirs and offers a theoretical foundation for evaluating individual layer contributions and productivity. 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

Sand is the backbone of modern civilization and faces heightened demand in the Anthropocene. The uncontrolled extraction of sand raises concerns regarding its irreversible ecological impact. The sand industry is not well understood, especially from the perspective of sustainability. To address this knowledge gap, this systematic review combines policy analysis with the use of material flow analysis (MFA) indicators, environmental externalities, and geopolitics to assess the overall sustainability of the sand industry. By utilizing trade data, this study identified the primary importers and exporters of sand within each continent and selected the top 3–4 countries for analysis. Based on these countries, relevant studies in the literature on the trade and domestic extraction of sand and that used the principles of MFA were found to assess the patterns of its consumption. Illicit sand mining adds a further challenge regarding data accuracy and verification. This study revealed that China’s consumption of sand surpasses that of all the other countries studied, at 17,700 million tonnes, and China has the highest mass of recycled aggregates in use. Using gross domestic product as a proxy for size of the economy, it was found that China consumed 0.001251 million tonnes of sand per million USD. European nations showed a striking balance in their sand industries by placing equal importance on using virgin sand and recycled aggregates, thus contributing to a circular economy. The use of MFA for future research can reveal hidden flows by positioning itself as a science–policy interface, enabling greater circularity within the lock-ins of the construction sector. Full article

The core structure of modern power systems reflects a fundamental symmetry between electricity supply and demand, and accurate load forecasting is essential for maintaining this dynamic balance. To improve the accuracy of short-term load forecasting in power systems, this paper proposes a novel model that combines a Multi-Strategy Improved Sand Cat Swarm Optimization algorithm (MSCSO) with a Self-Attention Temporal Convolutional Network (SA TCN). The model constructs efficient input features through data denoising, correlation filtering, and dimensionality reduction using UMAP. MSCSO integrates Uniform Tent Chaos Mapping, a sensitivity enhancement mechanism, and Lévy flight to optimize key parameters of the SA TCN, ensuring symmetrical exploration and stable convergence in the solution space. The self-attention mechanism exhibits structural symmetry when processing each position in the input sequence and does not rely on fixed positional order, enabling the model to more effectively capture long-term dependencies and preserve the symmetry of the sequence structure—demonstrating its advantage in symmetry-based modeling. Experimental results on historical load data from Panama show that the proposed model achieves excellent forecasting accuracy (RMSE = 24.7072, MAE = 17.5225, R² = 0.9830), highlighting its innovation and applicability in symmetrical system environments. Full article

The durability and fire resilience of concrete structures are increasingly critical in modern construction, particularly under elevated-temperature exposure. With this context, the current study explores the thermal and microstructural characteristics of geopolymer-based ultra-high-performance concrete (G-UHPC) incorporating quartz powder (QP) and silica fume (SF) after exposure to elevated temperatures. SF was used at 15% and 30% to partially replace the precursor material, while QP was used at 25%, 30%, and 35% as a partial replacement for fine sand. The prepared specimens were exposed to 200 °C, 400 °C, and 800 °C, followed by air cooling. Mechanical strength tests were conducted to evaluate compressive and flexural strengths, as well as failure patterns. Microstructural changes due to thermal exposure were assessed using scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS). Among the prepared mixtures, the 30SF35QP mixture exhibited the highest compressive strength (156.0 MPa), followed by the 15SF35QP mix (146.83 MPa). The experimental results demonstrated that G-UHPC underwent varying levels of thermal degradation across the 200–800 °C range yet displayed excellent resistance to thermal spalling. At 200 °C, compressive strength increased due to enhanced geopolymerization, with the control mix showing a 29.8% increase. However, significant strength reductions were observed at 800 °C, where the control mix retained only 30.8% (32.0 MPa) and the 30SF25QP mixture retained 28% (38.0 MPa) of their original strengths. Despite increased porosity and cracking at 800 °C, the 30SF35QP mixture exhibited superior strength retention due to its denser matrix and reduced voids. The EDS results confirmed improved gel stability in the 30% SF mixtures, as evidenced by higher silicon content. These findings suggest that optimizing SF and QP content significantly enhances the fire resistance and structural integrity of G-UHPC, providing practical insights for the design of sustainable, high-performance concrete structures in fire-prone environments. Full article

This paper presents a modern spectroscopic characterization of the synthetic oil from oil sands of Beke, Munaily-Mola, and Dongeleksor. The pyrolysis process was carried out at temperatures up to 580 °C with a controlled heating rate, and the products obtained were analyzed using Fourier transform infrared spectroscopy (FTIR), gas chromatography–mass spectrometry (GC–MSD), and nuclear magnetic resonance (NMR) spectroscopy. The FTIR spectra showed a predominance of aliphatic hydrocarbons in the sample from Munaily-Mola synthetic oil, while the content of aromatic compounds was higher in the sample from Beke. GC–MSD analysis revealed significant differences in the distribution of hydrocarbons between the samples, with the Munaily-Mola sample containing a higher proportion of heavy hydrocarbons. NMR spectroscopy provided additional information about the structural composition of the extracted oil. The results indicate the potential of pyrolysis as an effective method for processing oil sands, while the composition of the product varies depending on the geological origin of the raw materials. These findings provide valuable information for optimizing oil sands processing technologies and improving the efficiency of synthetic oil production. Full article

Traditional sand casting is limited by mold fabrication, cost control, and data collection, which restrict its further advancement. However, 3D sand printing technology represents a sophisticated rapid prototyping approach that directly utilizes three-dimensional models to fabricate complex sand molds and cores, thereby bypassing the traditional mold-making steps. This technology significantly enhances production efficiency and design flexibility, thereby advancing the modernization of casting processes. In the context of wind tunnel testing, the application of 3D-printed sand shell additive manufacturing has successfully produced sand molds and cores for the non-axisymmetric intake duct structures. This demonstrates the feasibility of this technology for complex casting applications and its capability to meet experimental requirements. Full article

Fabric-reinforced hybrid polymer composites are present in almost every sector of modern life, and most essential areas of research in recent years have focused on glass–carbon fabric with filler material composites. Fabric and fillers are employed in strengthening polymer composites with the aim of improving their mechanical and tribological properties. The primary objective of this investigation was to investigate thetribological and mechanical properties of unfilled and cenosphere-filled carbon–glass-reinforced polyester composite systems, utilizing two types of fabric (glass and carbon) with cenosphere filler in varying weight fractions (0, 2.5, 5, 7.5, 10, and 12.5 wt.%) for both carbon fabric and the cenosphere. The abrasive wear characteristics were evaluated using a stainlesssteel wheel abrasion tester, utilizing silica sand as the abrasive material. Tests were performed at various distances (360–1800 m) and loads (12 N and 24 N). The results show that the wear rate of carbon–glass fabric-reinforced polyester composites differs significantly, with and without cenosphere fillers. Notably, the unfilled composites exhibit the highest wear volume loss, indicating a substantial improvement in wear resistance with the addition of cenospheres. The results reveal that in carbon–glass fabric-reinforced polyester composites, specific wear rate decreases when more cenospheres are loaded. The wear rate was successfully reduced by cenospheresunder silica sand as an abrasive. Compared to unfilled composites, the mechanical properties of filled composites exhibit superior performance. These variations were explained by examining the worn-out surfaces under an SEM and correlating the features observed with the mechanical properties. Full article

Earth–Air Heat Exchange (EAHE) systems are an eco-friendly and energy-efficient technology as pre-heating or pre-cooling systems in civil buildings. Technically, the performance of the EAHE system is influenced by properties associated with the technology. In this paper, the focus is placed on the properties covered by the published literature to understand how they impact the efficiency of these systems. The review scrutinizes the implication of pipe properties such as the material type (steel, Polyvinyl Chloride [PVC], concrete, or high-density polyethylene), diameter and length, and depth in the context of modern building design and energy conservation. Other properties considered in this work are air velocity and the bonding of pipes with the soil. The EAHE systems’ performance is not significantly influenced by the pipe material, unlike the pipe length and diameter. It is reported that longer pipes enhance the cooling output in the EAHE system. The pipe length positively correlates with the in-pipe air temperature. An increment in the pipe diameter led to a drop in the in-pipe air temperature. An indicative report states that an increasing air flow velocity can lead to thermal losses from pipes to their surrounding soil. The addition of sand below and above the pipe enhances the thermal conductivity, just as an increase in the moisture content of the soil will contribute. There are attempts to use additives, construction waste, graphite, and fly ash as a backfill material, but with opposing economic feasibility. Construction waste could help the EAHE system to improve by 80%. A combination of graphite and fly ash as a backfill material is cost-effective. Research on the pipe material type and standards development are limited. Overall, the pipe material type and length to adopt for an EAHE system are based on the funds’ availability for the construction. Full article

Background/Objectives: Cataract surgery has evolved into a refractive procedure aimed at optimizing both vision quality and quantity. Modern patients, particularly “baby boomers”, expect superior outcomes, increasing demand for premium intraocular lenses (IOLs). However, ocular surface dysfunction (OSD), especially dry eye disease (DED), compromises postoperative satisfaction, with up to 35% of patients dissatisfied despite achieving 20/20 visual acuity. This study aimed to characterize postsurgical ocular surface system failure (OSSF) and explore strategies to improve perioperative management. Methods: An open observational study was conducted at the Ophthalmology Complex Operative Unit, University Campus Bio-Medico, Rome, Italy, enrolling 20 patients with stage N2–3 and C1–2 lens opacities. Patients with diabetes, prior surgeries, or ocular inflammatory diseases were excluded. Preoperative and postoperative assessments included OSDI, SANDE scores, Schirmer test, TBUT, and fluorescein staining. Follow-ups occurred at 1 week, 1 month, and 3 months postoperatively. Statistical analysis used two-way ANOVA (p < 0.05). Results: Despite achieving a BCVA of 20/20, 44% of patients reported OSSF symptoms. Postoperative evaluations revealed significant worsening in OSDI and SANDE scores (p < 0.001), Schirmer test (preoperative mean 19.92 ± 10.06; p < 0.001), and TBUT (preoperative mean 5.88 ± 2.64 s; p < 0.001). Meibomian gland dysfunction and conjunctival hyperemia also worsened. Conclusions: Postsurgical OSSF results from neurogenic inflammation, tear film instability, and meibomian gland dysfunction, exacerbated by surgical trauma. Preoperative and postoperative management, including artificial tears, lid hygiene, and preservative-free regimens, are essential to improve outcomes and patient satisfaction. Comprehensive strategies can mitigate symptoms and enhance the benefits of cataract surgery. Full article