Search Results (736)

This study examines the marble resources of the Mani peninsula, southern Greece, a region that has long been known for its white, gray-black (bigio antico), green (cipollino verde Tenario), and particularly red (rosso antico or lapis Taenarium) and dark (nero antico) marbles. Based on extensive fieldwork, more than 90 quarrying sites were documented, several of which were recorded for the first time. This study provides a systematic characterization of these stones through combined mineralogical, petrographic, and stable isotopic (δ¹⁸O, δ¹³C) analyses of 27 representative samples. The results confirm the presence of calcitic marbles, which vary in color due to hematite in the red varieties, graphite and organic matter in the gray-black and black types, and chlorite in the green marbles. The isotopic results demonstrate a generally high degree of homogeneity, although the red marbles display greater variability, complicating their distinction from analogous stones in Asia Minor, such as those from Iasos and Milas. Quarrying of Mani marbles began in the Bronze Age and reached its peak during Roman times. It continued into the Byzantine period, with renewed exploitation in the 19th and 20th centuries. This study highlights the significant role of Mani in the ancient marble trade and contributes to ongoing debates about the provenance of famous red, white, and black marbles across the Mediterranean. Furthermore, it establishes a strong reference framework, integrating new analytical results with the existing literature, providing an updated mineralogical, petrographic, and isotopic database for provenance studies of marble artifacts. Full article

This study presents the results of an archaeometric investigation of white marble votive reliefs from the Roman city of Pautalia (modern Kyustendil, Bulgaria), with the aim of clarifying patterns of material selection, production, and connectivity within the eastern provinces of the Roman Empire. Although these votive monuments, primarily dated to the 2nd and 3rd centuries AD, have long been examined from stylistic, iconographic, and epigraphic perspectives, the provenance of the marble used in their manufacture has remained largely unexplored. A total of 27 votive reliefs from urban and extra-urban sanctuary contexts were analysed using a multi-method approach combining petrographic analysis, stable isotope ratios (δ¹³C and δ¹⁸O), and trace element analysis by ICP-MS, and compared against an extensive geological reference database of ancient marble quarries. The results indicate a clear predominance of local and regional marble sources, alongside a limited but meaningful presence of imported material. This distribution pattern supports the existence of local workshops operating in or near Pautalia, which relied primarily on nearby quarry sources while selectively incorporating imported marble, likely through the reuse of pre-existing blocks or workshop offcuts rather than through systematic long-distance supply. These findings underscore Pautalia’s role as a regional production centre and as a nodal point within wider networks connecting the Aegean world and the Balkan hinterland. Full article

Work-related musculoskeletal disorders (MSDs) are leading causes of disability and productivity loss globally, yet registry-based evidence from low- and middle-income countries remains limited. The study analyzed compensated work-related MSDs claims reported to the Workers’ Compensation Fund (WCF) in Tanzania between 2016 and 2022 to identify patterns and associated risk factors. A registry-based cross-sectional design was conducted using de-identified WCF data on demographics, occupation, industry, diagnosis, and recorded workplace exposures. Modified Poisson regression was used to estimate associations between work-related MSDs and risk factors. Among the 243 workers with work-related MSDs whose claims were accepted and compensated, 84% had low back pain (LBP), predominantly males (90%) and middle-aged workers (mean age 41.6 years). Mining and quarrying accounted for 50% of the cases, with drivers and mobile plant operators being the most affected. Whole-body vibration (WBV) exposure and work in mining and quarrying were significant predictors of LBP (adjusted PR = 1.25; 95% CI: 1.061.49 and PR = 1.21; 95% CI: 1.01–1.44, respectively). These findings highlight WBV and mining work as significant risk factors of work-related MSDs and underscore the need for targeted interventions alongside enhanced health surveillance systems for exposure documentation. Full article

Epoxy–granite (EG) composites, comprising granite quarry waste and low-cost epoxy, present a sustainable alternative to cast iron for machine tool foundations. This study develops a data-driven simulation framework to enhance the mechanical properties of epoxy–granite systems by integrating published experimental data with Gaussian Process Regression (GPR) surrogate modeling and Bayesian optimization (BO). The objective is to maximize compressive strength and vibration damping—both critical factors for machining accuracy and dynamic stability. Experimental results from composites with 12–25 wt% epoxy and varied aggregate gradations demonstrate compressive strengths up to 76.8 MPa and flexural strengths reaching 35.4 MPa. The peak damping ratio of 0.0202 was observed at intermediate epoxy content. Mixtures enriched with fine particles also exhibited enhanced fracture toughness and low water absorption, outperforming cementitious concretes, polymer concretes, and natural granite. To address the limitations of experimental coverage, a GPR-based simulation model was employed to explore the four-dimensional design space defined by epoxy content and aggregate fractions. Integrated with BO under realistic manufacturing constraints, the framework identifies optimal formulations comprising 22–26 wt% epoxy and 55–70% fine aggregates. These compositions yield predicted compressive strengths of 78–85 MPa and damping ratios approaching 0.022, indicating significant improvement in overall mechanical properties. Bayesian Weibull analysis further quantifies reliability, revealing shape parameters α ≈ 2.4–2.9, which indicate consistent performance with moderate variability. This work presents the first reported application of an integrated GPR-BO-Bayesian Weibull simulation framework to epoxy–granite composites, enabling simultaneous optimization of conflicting objectives and probabilistic reliability assessment of key mechanical properties. The approach reduces experimental effort by over 70% and supports the circular economy through valorization of granite waste in high-value manufacturing. Nonetheless, predictive uncertainty remains high in under-sampled regions (e.g., damping with n = 2). Future experimental validation—comprising at least 10–15 data points across varied epoxy ratios and gradations—is essential to corroborate the predicted optimum. Full article

The marble extractive industry heavily depends on diesel-powered equipment, particularly wheel loaders and excavators used for block handling, resulting in high energy consumption and operating costs. In this study, the potential for fuel reduction through managerial and technological transitions was evaluated using the example of the marble quarry located in the Carrara basin. The energy demand of excavators, wheel loaders, and dumpers was characterized using telemetry data gathered through an Industry 4.0 methodology. A standard elementary cycle was modeled via the program evaluation and review technique (PERT) to map productive tasks and idling periods. To ensure comparability, a specific consumption coefficient (SCC) was defined. Subsequently, a novel fuel handling index (FHI) is proposed to prioritize investments by accounting for the uncertainties and production variables typical of quarry projects. Results demonstrate that while idle management offers a 4% fuel reduction, transitioning to hybrid wheel loaders represents a more significant strategy, achieving a 12% saving among the scenarios analyzed. The full-hybrid scenario leads to a cumulative 17% reduction. This framework supports decision-making for energy efficiency in high-yield extraction sectors, mitigating the economic risk associated with technological transitions. Full article

This study investigates how natural fillers of different origins and morphologies influence the structural, thermal, rheological, and mechanical properties of thermoplastic elastomers (TPEs). Two series of materials were prepared: one based on a biobased matrix, poly(butylene 2,5-furandicarboxylate)-block-poly(tetramethylene oxide) (PBF-PTMO), and one based on a petroleum-derived matrix, poly(butylene terephthalate)-block-poly(tetramethylene oxide) (PBT-PTMO). Both series incorporated a range of natural modifiers, i.e., lignocellulosic fibers and ground fractions of Arundo donax L., cyanobacterial biomass (Spirulina platensis), and silica-rich mineral dust originating from volcanic stone quarries. The materials were obtained via melt blending, while the reference matrices (neat block copolymers) were synthesized through melt polycondensation. The chemical structure and limiting viscosity number (LVN) of the neat matrices were confirmed, while differential scanning calorimetry (DSC) provided insight into their morphology and phase composition. Scanning electron microscopy (SEM) was employed to evaluate the morphology and distribution of the modifiers within the polymer matrices. To assess how the fillers influenced processing windows and performance, thermogravimetric analysis (TGA), oscillatory rheological measurements, and tensile testing were performed. The results provide insight into structure–property relationships governing natural filler–TPE interactions and support the development of more sustainable elastomeric composites with tailored performance. Full article

The growing need for a cleaner, sustainable environment has increased interest in reusing waste materials that cause pollution. In this research, the mechanical (dry density, compressive, and tensile strength) and also durability properties (sorptivity, rate of water absorption, chloride ion resistance, and resistance to freeze–thaw) of concrete were studied by partially substituting cement with brick powder (BP) and sand with quarry dust (QD). The proportions of brick powder replacement with cement were in the range of 5%, 10%, 15%, and 20% by weight. Likewise, QD was used in the range of 15%, 30%, 45%, and 60% by weight of natural sand. Both materials were used separately as well as simultaneously in concrete. Concrete mixtures were prepared, tested after curing, and then compared with conventional concrete. The water–cement (w/c) ratio was kept constant at 0.55 for all the mixes. According to experimental results, the concrete made with brick powder and quarry dust resulted in improved dry density. After curing for 28 and 56 days, the compressive and splitting tensile strengths increased by substituting cement with brick powder up to 15%. Brick powder showed a higher strength activity index than required according to the standard. Also, compressive and splitting tensile strengths significantly increased by replacing natural sand with quarry dust up to 60% at all curing ages. Combined mixes with partial replacements of cement and sand with brick powder and quarry dust, respectively, also showed improvements in the compressive and splitting tensile strength at all ages. Sorptivity and rate of water absorption decreased with the addition of BP and QD. Moreover, brick powder and quarry dust mixes showed higher resistance to chloride ion penetrability and higher resistance to freeze–thaw as the replacement level increased. Microstructural analysis of hard concrete samples also confirmed the enhanced mechanical strength and durability due to brick powder and quarry dust. Full article

This study presents a statistical modeling approach for predicting the operational reliability of induction motors used in dump truck drives. The proposed method uses censored data, including both time to failure and data on properly operating engines, to assess reliability indicators, such as uptime based on Weibull and lognormal distributions. A generalized “life curve” of the stator and bearing unit is constructed, which makes it possible to determine interval estimates of the service life and residual service life. The model is implemented as software for calculating distribution parameters and visualizing reliability dependencies. Approbation based on the operational data of quarry transport confirmed the applicability of the proposed approach for diagnosing and optimizing the maintenance system of induction motors of heavy equipment. Full article

This study introduces a Blasting Safety Index (BSI), a composite analytical framework for quantifying the cumulative mechanical, environmental, and geotechnical effects of quarry blasting operations. The index integrates ground vibration expressed as Peak Particle Velocity (PPV), noise, dust concentration, and slope stability, each normalized and weighted according to its operational relevance, to provide a unified measure of blasting-related risk. Field application in a pyroxenic andesite quarry is presented as a demonstrative pilot case illustrating the internal coherence and operational feasibility of the proposed framework and resulted in a BSI value of 0.91, classifying the operation as high risk despite full compliance with individual regulatory thresholds. Within the applied weighting structure, PPV represented the dominant contribution to the composite index, reflecting its widely documented influence on blast-induced safety outcomes. The proposed methodology offers a transparent, measurement-based decision-support tool for operational control, regulatory communication, and environmental impact assessment. Owing to its compatibility with digital monitoring ecosystems, the BSI supports the advancement of sustainable, risk-aware, and technically optimized blasting practices within modern quarry operations. Full article

Rockfall hazard assessment and mitigation design relies heavily on three-dimensional trajectory modeling, in which the coefficient of restitution (COR) is a governing parameter controlling rebound, energy dissipation, and runout distance. In practice, COR values are commonly selected from generalized tables based on slope material type, introducing significant epistemic uncertainty and limiting predictive accuracy. This study presents a comparative evaluation of large-scale field rockfall experiments and 3-D numerical simulations conducted at a former aggregate quarry in Boise, Idaho, to assess the performance of tabulated restitution coefficients. Concrete blocks of controlled shape (spheres, cubes, and rectangular prisms) and mass (17–68 kg) were instrumented with inertial sensors and released from two slope configurations. High-resolution UAV-based LiDAR was used to reconstruct slope geometry, while dynamic cone penetrometer and friction tests were performed to characterize spatial variability in slope material stiffness. These data were incorporated into RocFall3 to simulate block trajectories using spatially varying COR values. Initial models assuming zero rotational velocity and tabulated COR ranges failed to reproduce observed runout distances, dispersion patterns, and modes of motion, particularly for non-spherical blocks. Incorporating field-measured initial rotational velocities significantly improved agreement between modeled and observed trajectories, by correcting the unrealistic sliding mode of motion previously observed. However, quantitative discrepancies in deposition and dispersion persisted, highlighting limitations associated with simplified slope geometry and the loss of small-scale surface features during LiDAR surface reconstruction. The results demonstrate that restitution behavior is strongly shape-dependent and that realistic initial conditions are essential for physically meaningful simulations. The findings underscore the need for site-specific, material-informed approaches to COR estimation and for improved integration of high-fidelity field data into physics-based rockfall models. Full article

Foam concrete is well-appreciated for its thermal and acoustic benefits and is prepared by introducing foam into cement slurry/mortar. The current research examines the feasibility of Quarry Micro Fines (QMF), a waste generated from the quarries during sand manufacturing, as a substitute for fine aggregate in the preparation of foam concrete. During the preparation of concrete, a portion of cement is replaced with sugarcane bagasse ash (SCBA), while polypropylene (PP) fibers are added to improve the shrinkage resistance and tensile strength of the resulting concrete. A three-factor, three-level Box–Behnken Design (BBD) in Response Surface Methodology (RSM) was used to optimize the compressive strength of foam concrete, considering QMF (0%, 50%, 100%) by weight of fine aggregate, SCBA (0%, 10%, 20%) by weight of cement, and PP fiber (0.2%, 0.4%, 0.6%) by volume of foam concrete as variables. The three mixtures, including control (FC), mix with 50% QMF, 10% SCBA, and 0.4% PP fiber (F50S10F0.4), and mix with 100% QMF, 10% SCBA, and 0.4% PP fiber (F100S10F0.4), were chosen for a more in-depth investigation based on the test results. While Q50S10F0.4 achieved the highest compressive strength (6.18 MPa), Q100S10F0.4 showed the best overall performance, with low water absorption of 14.10%, porosity of 20.17%, UPV 2388 m/s, and RCPT values of 1407.96 Coulombs. The modified mixtures exhibited enhanced bonding and pore enhancement as demonstrated by scanning electron microscopy and mercury intrusion porosimetry analyses. The study highlights the effective use of QMF, SCBA, and PP fibers in producing high-performance, sustainable foam concrete. Full article

Particulate Matter (PM) is a type of air pollution that poses risks to human health, the environment, and property. Among the various PM types, PM₁₀ is particularly significant, as it acts as a vector for numerous hazardous trace elements that can negatively impact human health and the ecosystem. Identifying potential sources of PM₁₀ and quantifying their impact on ambient concentrations is crucial for developing efficient control strategies to meet threshold values. Receptor modeling, which identifies sources using chemical species information derived from PM samples, has been widely used for source apportionment. In this study, PM₁₀ samples were collected over three periods (April, May, and June 2021), each lasting 16 days, using semi-automatic dust sampling systems at two sites in Biga, Canakkale, Turkiye. The relative contributions of different source types were quantified using EPA PMF (Positive Matrix Factorization) based on 35 elements comprising PM₁₀. As a result of the analysis, five source types were identified: crustal elements/limestone/calcite quarry (64.9%), coal-fired power plants (11.2%), metal industry (9%), sea salt and ship emissions (8.5%), and road traffic emissions and road dust (6.3%). The distribution of source contributions aligned with the locations of identified sources in the region. Full article

Approximately 50% of individuals diagnosed with Stage I liver cancer live beyond four years; however, a small subset of Stage I patients die within the first year. A prognostic biomarker panel that can identify high-risk Stage I patients may be extremely valuable. In this study, we used the Long–Evans Cinnamon (LEC) rat model of Wilson’s Disease and hepatocellular carcinoma (HCC), along with data from The Cancer Genome Atlas (TCGA) human database, to create a novel biomarker panel. We generated and analyzed a rat microarray gene expression profile by comparing liver tumor tissues with adjacent normal tissues from the same animals, covering approximately 30,000 genes. The microarray results were translated into a five-gene panel associated with 1-year survival in Stage I liver cancer patients based on TCGA data, in combination with machine learning and bioinformatics approaches. The panel was internally validated following the “REporting recommendations for Tumor MARKer prognostic studies (REMARK)” guidelines. With no existing Stage-I-specific prognostic tools, a biomarker panel associated with 1-year survival in patients with Stage I liver cancer is a potential candidate for rigorous external validation. Full article

The relict bedding and slaty cleavage structure in slate directly influences the crushing characteristics and strength properties of slate aggregates. When slate aggregates are used in asphalt concrete, it may have risks of insufficient resistance to crushing and uncertain long-term durability. In order to investigate the crushing behavior of slate coarse aggregates in asphalt mixtures, a comparative study was conducted using limestone and basalt aggregates as reference. Various tests were carried out including crushing value tests, single-particle compression crushing tests, Marshall compaction resistance tests, and gyratory compaction resistance tests. The crushing patterns, crushing strength, and gradation changes of slate aggregates after crushing were systematically examined. Based on the Weibull distribution function, the statistical distribution of single-particle crushing strength was analyzed. Additionally, the particle distribution patterns were studied for single-sized aggregates, blended aggregates, and asphalt mixtures after these were subjected to crushing under Marshall compaction and gyratory compaction. The test results indicated that the crushing value of slate coarse aggregates was 9.2%, which indicates superior crushing resistance compared to traditional limestone and basalt. After long-term exposure to water immersion at 60 °C, high-pressure steam treatment, and heating at 220 °C, the increase in crushing value of slate coarse aggregates was less than 1.5%, indicating excellent water and heat resistance. The two-point and four-point crushing strengths of single particles of slate coarse aggregates were higher than those of limestone and basalt coarse aggregates, and the single-particle compression crushing strength followed the Weibull distribution pattern. Both single-sized and blended slate aggregates exhibited lower proportions of crushing during Marshall and gyratory compaction compared to basalt and limestone aggregates. Asphalt mixtures prepared with slate coarse aggregates also demonstrated better crushing resistance than those made with basalt and limestone, confirming that the bedding structure of slate does not cause excessive crushing in asphalt mixture. The obtained findings were limited to the tested slate aggregates from a single quarry and thus necessary performance verification should be conducted on slate aggregates from other sources before practical engineering applications. Full article

The sustainability of resources and ecological integrity are significantly influenced by land use and land cover change (LULCC) dynamics, particularly in ecotonal semi-arid regions where biome transitions are highly sensitive to anthropogenic disturbance and climatic variability. This study aims to assess historical LULCC dynamics and spatial reconfiguration across nine classes (grassland, shrubland, wetlands, forestland, waterbodies, farmed land, built-up land, bare land, and mines/quarries) in the C5 Secondary Drainage Region of South Africa over the three periods 1990–2014, 2014–2022, and 1990–2022. Using the South African National Land Cover datasets and the TerrSet liberaGIS v20.03 Land Change Modeller, this research applied post-classification comparison, transition matrices, asymmetric gain–loss metrics, and patch-based landscape analysis to quantify the magnitude, direction, source–sink dynamics, and spatial reconfiguration of LULCC. Results showed that between 1990 and 2014, Shrubland expanded markedly (+49.1%), primarily at the expense of Grassland, Wetlands, and Bare land, indicating bush encroachment and hydrological stress. From 2014 to 2022, the trend reversed as Grassland increased substantially (+261.2%) while Shrubland declined sharply (−99.3%). Forestland also regenerated extensively (+186%) along riparian corridors, and Waterbodies expanded more than fivefold (+384.6 km²). Over the long period between 1990 and 2022, Built-up land (+30.6%), Cultivated land (+16%), Forestland (+140%), Grassland (+94.4%), and Waterbodies (+25.6%) increased, while Bare land (−58.1%), Mines and Quarries (−56.1%), Shrubland (−98.9%), and Wetlands (−82.5%) decreased. Asymmetric analysis revealed strongly directional transitions, with early Grassland-to-Shrubland conversion likely driven by grazing pressure, fire suppression, and climate variability, followed by a later Shrubland-to-Grassland reversal consistent with fire, herbivory, and ecotonal climate sensitivity. LULC dynamics in the C5 catchment show class-specific spatial reconfiguration, declining landscape diversity (SHDI 1.3 → 0.9; SIDI 0.7 → 0.43), and patch metrics indicating urban and cultivated fragmentation, shrubland loss, and grassland consolidation. Based on these quantified trajectories, we recommend targeted catchment-scale land management, shrubland restoration, and monitoring of anthropogenic hotspots to support ecosystem services, hydrological stability, and sustainable land use in ecotonal regions. Full article