Search Results (170)

This study develops workflows derived from the non-contact survey of small anthropic markers along the northern stretch of Pompeii’s urban walls. For valid reasons currently being verified, these indentations have been attributed to the impact of darts fired by Sulla’s artillery in 89 BC. Consistent with published findings, the morphometric data obtained from the casts of the impressions generated by the metal tips were used to obtain measurement modules suitable for measuring the reconstruction of SCORpiò-NIDI. To achieve this result, calibration formulas handed down directly from the Greeks and Romans were used. The method adopted reverses the usual sequence, starting from the effects and arriving at the causes. According to the principles handed down by ancient treatise writers, typical 2D-3D graphic modeling investigations guided the commensuration of parts. A family of dart-launcher prototypes was created based on the measurement module, to be tested and mechanically analyzed through reverse engineering processes. The creation of virtual models was not based on the dimensions of the findings, but rather on parameters that study the reaction of stone blocks to the impact of blunt objects. The results aim to raise operational criticism, contributing to the debate on “certified” typological families of reconstructions based on objective data and verifiable calculations. Full article

This study investigated the communication performance of ultrahigh-frequency radio-frequency identification (RFID) systems with embedded RFID tags on challenging roads. Surface-mounted RFID tags are used for vehicle guidance. However, in snowy regions, they are vulnerable to damage caused by snow removal. Accordingly, RFID tags were embedded beneath the road surface, and the influence of an installation angle of 30° on communication performance was evaluated. Using the appropriate installation angle for asphalt embedding, this study investigated unpaved roads, where tag stability is influenced by water flow and soil displacement. To improve durability, RFID tags were attached to geocell-based reinforcement structures using polyvinyl chloride (PVC) pipe holders. The communication performance was comparable to that of asphalt-embedded configurations. To further improve installation, a concrete-block-based embedding approach was investigated. Gravel concrete and mortar concrete block produce significant electromagnetic attenuation, which reduces the communication range. Therefore, a hybrid design using PVC pipes embedded in commercially available concrete blocks and holes filled with crushed stone was developed. This design achieves the communication range required for reliable vehicle navigation while simplifying installation and enabling application on natural soil unpaved roads without geocell reinforcement. Full article

This study aims to clarify the mesoscopic damage evolution mechanisms of concrete subjected to rigid projectile penetration and provide support for the optimal design of high-performance protective structures. Based on the ABAQUS/Explicit finite element framework, a three-phase mesoscopic numerical model of concrete considering aggregate, mortar matrix, and interfacial transition zone (ITZ) is constructed. By combining the random convex polygon algorithm with the background mesh mapping technique, the intrinsic geometric features of stochastic materials such as crushed stone and pebble are accurately characterized. The effects of aggregate geometric characteristics, volume fraction, and projectile motion/geometry parameters (velocity, length–diameter ratio, curvature radius of the warhead CRH) on the damage evolution of the target, penetration depth, and velocity attenuation law are systematically investigated. The results reveal that increased aggregate angularity substantially enlarges both tensile and compressive damage zones and promotes crack bifurcation, which collectively enhances kinetic energy dissipation, reduces penetration depth, and accelerates projectile deceleration. Increasing the aggregate volume fraction can significantly enhance the anti-penetration resistance of the target. A high proportion of aggregate grains effectively enhances the structural toughness by blocking the crack propagation path. Penetration velocity, length–diameter ratio, and CRH are the core elements determining the penetration efficiency, and the increase in their values will lead to a significant increase in penetration depth and induce a change in the damage mode from local failure to large-scale cracking. The mesoscopic model and related conclusions established in this study can provide a theoretical foundation and numerical benchmark for the impact resistance design, optimization, and damage assessment of high-strength concrete protective structures. Full article

Saimaluu-Tash I, located in a high-altitude glacial valley in Kyrgyzstan, preserves one of Central Asia’s largest and most culturally significant concentrations of rock engravings. Despite extensive archaeological research, the physical, mechanical, and chromatic properties of the sandstone substrates relevant for conservation assessment remain poorly characterized. This study integrates petrographic microscopy, scanning electron microscopy, colorimetry, and Vickers hardness testing with the digital documentation of twelve engraved blocks to evaluate weathering processes, engraving practices, and long-term preservation. The engravings are carved into arkosic sandstone with carbonate cement, characterized by a weathered surface enriched in clay minerals and covered by a dark surface coating (patina). Weathered surfaces exhibit significantly lower hardness (0.6 ± 0.2 GPa) than unweathered stone (2.8 ± 0.6 GPa), which facilitated the engraving of the petroglyphs by allowing tools to penetrate more deeply into the stone. Colorimetric analyses reveal a strong chromatic contrast between the surface patina and the lighter sandstone exposed by engraving (ΔE ≈ 22.7). This contrast would have enhanced the original visibility of the petroglyphs and highlights potential conservation issues associated with the progressive reformation of this surface layer. Iconographic analysis identifies recurrent themes related to hunting, herding, mobility, animal management, and symbolic spatial practices within a nomadic high-mountain landscape. Overall, the results demonstrate how an integrated material and interpretative approach contributes to understanding rock art production processes. They support preventive and sustainable conservation strategies for vulnerable engraving landscapes shaped by long-term interactions between geological processes and human activity. Full article

Low block recovery in dimensional stone quarrying is commonly associated with complex fracture systems and inconsistent decision-making across the extraction chain. An integrated decision-support workflow is presented, linking rock-mass characterization and extraction planning. It combines discrete fracture network (DFN) modelling with block usability assessment and staged decision gates to reduce structural uncertainty. Application of the framework across seven-dimensional stone quarries indicated relative improvements ranging from approximately 8–12% in commercial block recovery compared with conventional quarrying approaches. These improvements were associated with enhanced fracture characterization, improved selection of extraction orientations, more effective assessment of block usability, and NDT-supported quality control. Full article

In the surface protection of stone and brick cultural heritage, a primary challenge is that traditional polymeric coatings are prone to photooxidative degradation under ultraviolet (UV) irradiation, and the resulting aged fragments readily block the substrate micropores, leading to a loss of “breathability”. To address the performance conflict among waterproofing, breathability, and weather resistance, this study prepared few-layer Ti₃C₂T_X MXene using a minimally intensive layer delamination (MILD) method. The poor compatibility between MXene and the fluorosilicone (FPS) resin matrix was effectively resolved through covalent modification with a silane coupling agent (KH-550). Results demonstrate that at an ultralow loading (0.5 wt%), the functionalized f-MXene is uniformly dispersed within the resin. This structure not only spontaneously constructs a hierarchical rough architecture on the surface that imparts high hydrophobicity (water contact angle of 131.6°), but its internal “labyrinth effect” also effectively blocks corrosive media. Simultaneously, the intrinsic water vapor transmission rate of the substrate is effectively maintained (with a reduction of less than 3%), and no visually perceptible color difference is generated (∆E = 1.2). Mechanically, f-MXene relies on interfacial interactions to act as a “nano-skeleton” for stress transfer, thereby increasing the uniaxial compressive strength of fragile limestone by 32.4%. Optical and spectroscopic characterizations further elucidate its anti-aging mechanism: f-MXene not only provides broadband UV shielding but also exhibits highly efficient radical scavenging activity during long-term UV aging. After 400 h of aging, the concentrations of hydroxyl and superoxide anion radicals within the system are significantly reduced, blocking the photooxidative chain reaction from the source. This work develops a composite protective material system for stone cultural heritage that simultaneously integrates high moisture permeability, minimal visual intervention, and long-term antioxidant performance. Full article

The city of Veracruz preserves buildings mainly constructed during the 16th and 17th centuries, where carved madreporic coral was used as ashlar and as a component in mortars. These historic structures, now part of Mexico’s built heritage, show various degrees of deterioration caused by erosion and prolonged exposure to environmental elements. Restoration using original materials is currently nearly impossible due to ecological restrictions protecting coral reefs. In this context, and under the principles of the tailor-made technique, the present research revisits physico-mechanical and chemical studies conducted on the corals used in the construction of one of the most representative buildings in the city. The results were compared with those obtained from the formulation of experimental mortars using readily available materials—such as air lime, siliceous aggregates, and calcium carbonate—with the aim of reproducing the physical, mechanical, and chemical properties observed in the original corals. Laboratory tests allowed evaluation of their compatibility and performance, seeking to develop alternative materials that enable conservation interventions without compromising the integrity of the base material or the historic structures. The design of mortars is intended to be used in the restoration processes of buildings that are part of the built historical heritage. This is the starting point for understanding the characteristics of the mortar and its compatibility with the substrate, which could be used for repairing stone blocks and for preparing new mortars for masonry and plastering, since research on restoration mortars has largely overlooked this type of building with coral masonry due to its rarity. Therefore, this research is of particular interest. The mixtures formulated with calcareous sand were the most compatible with the reference coral material, while those made with silica sand exhibited properties superior to the corals, and marine sands showed very poor behavior, potentially compromising the integrity of the buildings. In physical–mechanical tests, formulations that include calcareous sand and silica sand (2 mm) demonstrated behavior closest to that of coral, consistent with chemical analysis results, where mortars formulated with calcareous sand registered the highest contents of CaO and portlandite. Mercury intrusion porosimetry indicated that the mortar formulated with silica sand (2 mm) has a porosity only 4.07% lower than that of the coral, while mortars formulated with calcareous sand and lime paste are between 11.17% and 16.87% lower. Therefore, one of the mixtures that stands out as the best option due to its similarity in physical–mechanical and chemical results is the composite that is not found at the extremes of the results obtained in the various tests carried out. The use of calcareous sand, as previously mentioned, enhances its behavior and affinity with the coral masonry, as demonstrated in the tests. Full article

The mechanical properties of stone masonry and its behavior under monotonic and cyclic loading depend significantly on the local properties of the masonry and the wall typology. This paper presents preliminary results from in situ inspection of stone masonry typologies at several locations in the Kvarner Littoral of Croatia, which revealed the use of earth mortar in a building over 200 years old instead of the commonly used lime mortar. This finding prompted the selection of this building as a case study, for which a detailed visual survey was conducted and laboratory testing employed to characterize the masonry components. The visual inspection showed that the walls of the case study building are constructed from non-degraded stones, with wedges between the blocks and larger corner blocks. The earth mortar is degraded on the wall surface, so non-destructive testing was unsuccessful. Laboratory tests on stone specimens confirmed high compressive strength (over 135 MPa), while laboratory tests on earth mortar specimens indicated compressive strength between 2.22 and 2.65 MPa. The stone compressive strength is comparable to that of high-quality Croatian limestones, while the compressive strength of the earth mortar is comparable to that of historic lime mortars. Microscopic analysis and FTIR spectroscopy of the earth mortar revealed that it does not contain sand or gravel, what distinguishes it from commonly used historic earth mortars, where clay minerals serve as a binder for sand and silt particles. This study presents the first comprehensive research on the material properties of an earth mortar in Croatia. Full article

Radon is a significant indoor air pollutant and a leading cause of lung cancer in non-smokers. While geogenic radon potential is well-documented, the specific contribution of building materials—particularly historic stones and those containing industrial by-products—requires precise in situ characterization to ensure public safety. This study investigates radon activity concentrations and surface exhalation rates across three distinct case studies in Slovakia: a mid-20th-century structure with cinder blocks, a UNESCO-protected Gothic building featuring volcanic andesite, and a historic stone plinth. Continuous radon monitoring and accumulation chamber measurements were employed, integrated with the tracking of meteorological parameters. The results revealed the highest surface exhalation rate in cinder block masonry (8.98 Bq m⁻² h⁻¹), followed by andesite ashlars (7.9 Bq m⁻² h⁻¹) and stone (1.87 Bq m⁻² h⁻¹). A clear correlation was observed between indoor radon levels and barometric pressure, whereas the influence of outdoor temperature appeared negligible. An estimated Activity Concentration Index of 0.30 suggests that the volcanic rock is likely radiologically safe for use as a bulk building material. The study concludes that while specific materials contribute to exhalation, indoor radon stability is primarily governed by barometric variations and the effectiveness of floor barriers against geogenic ingress rather than the masonry itself. Full article

Mountainous areas are prone to extreme climatic conditions, and the lack of modern infrastructure makes it difficult to achieve sustainable construction. To overcome the challenges of thermal comfort, robustness, and post-occupancy performance in hazard zones like the Neelum Valley in Pakistan, this research proposes a Digital–Vernacular Integration Model (DVIM), which integrates traditional architectural expertise with modern digital technology. The research design was based on mixed-methods research with the integration of qualitative information obtained through interviews and household surveys (n = 120), and quantitative measures of indoor thermal environments and hazards-based spatial analysis. Vernacular buildings made of wood, stone, and mud were digitally reconstructed using geometric modeling with SketchUp and Autodesk Revit with building information (BIM)-based modeling for assigning materials’ properties. Simulations were carried out using DesignBuilder software with EnergyPlus engines for assessing thermal environment, snow resistance, and seismic resistance to local hazards. The incorporation of the double-layered wall resulted in the improvement of heat retention by 12 to 15%. Moreover, the optimized roof and walls of the hybrid model resulted in the reduction of the sensible heating demand by 42% when compared to the conventional log houses and nearly 80% when compared to the conventional concrete block houses of the modern era. The proposed hybrid model resulted in R-values ranging from 33 to 40 m²·K/W, which are significantly higher when compared to the R-values for conventional timber walls (R = 15 m²·K/W) and concrete block walls (R = 1.0 to 1.3 m²·K/W). These results show the effectiveness of the digitally optimized hybrid model in improving the thermal performance in severe climatic conditions. The results clearly show that the integration of traditional architecture with digital simulation can ensure that modern comfort and safety standards are met without affecting the cultural identity of the region. The proposed framework will be implemented in pilot projects to ensure that the hybrid architectural models are incorporated into regional building regulations. Full article

Stone-built cultural heritage sites face significant threats from weathering and environmental stress, leading to structural damage or even total collapse. Consequently, robust monitoring and conservation strategies are essential. This study introduces the Monument Rockfall Risk Assessment (MRRA), a heuristic prioritization framework designed for the rapid ranking of detachment risks in monumental contexts. The MRRA was tested on the Piazzale Michelangelo Ramps in Florence (Italy), which are prone to rockfall hazard due to the presence of unstable blocks made of Pietraforte sandstone. The methodology employs a qualitative-heuristic risk rating approach, considering factors such as joint characteristics, centre of gravity location, and estimated kinetic energy of falling blocks. Susceptibility, vulnerability, and elements at risk were evaluated for each unstable block to calculate a relative risk index, which was then aggregated to determine the overall risk of each coping. The methodology was applied to a recent rockfall event that occurred in 2020 and compared with expert judgement to evaluate the model’s performance in identifying criticalities. Since decisions on defence and restoration works depend on geomechanical, social, and economic factors, this study explores an approach to establish optimal risk rating thresholds for the MRRA methodology, balancing false and missed alarms. Full article

Dry stone structures, especially in the Mediterranean area, are often represented as cultural heritage buildings. The strategic goal is to preserve significant structures; therefore, it is necessary to know as well as possible what their behaviour is as a result of the expected actions. On the basis of this, appropriate decisions can be made in case of necessary retrofitting. One of the most destructive actions on structures is an earthquake. Therefore, this paper assessed the behaviour of three dry stone historical structures under seismic loading in the historic centre of the city of Split in Croatia. The bell tower of St. Domnius Cathedral, the Eastern colonnade, and the Prothyron in Diocletian’s Palace were analysed. The presented numerical analyses were processed using the Y-2D computer programme, based on the combined finite-discrete element method. The structures were modelled with plane models in which stone blocks were modelled as discrete elements. This numerical model, in addition to allowing the estimation of seismic resistance, provides a very realistic expected failure mechanism, which is its significant advantage. Namely, this information is crucial for determining appropriate measures in case structural repairs become necessary for these types of structures. In the framework of this paper, this is exactly what was used to determine the place where the structure needs to be strengthened. By incrementally increasing the ground acceleration, the seismic resistance of the structures with the original geometry for all three earthquakes were first analysed. After the mode of the failure mechanism was obtained, structures were strengthened with clamps and the influence of retrofitting on the seismic resistance and failure mechanism was analysed for the case of the most unfavourable earthquake load. 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

Habitat loss and fragmentation threaten forest-dependent ungulates in subtropical mountain systems, yet integrative assessments linking habitat quality and landscape configuration remain limited. Here, we evaluated habitat suitability and identified core habitat patches for the endangered black muntjac (Muntiacus crinifrons) in Tongboshan National Nature Reserve using an Analytic Hierarchy Process–Habitat Suitability Index (AHP–HSI) framework integrated with camera-trap validation and landscape pattern analysis. Vegetation-related indicators (NDVI and vegetation type) were the dominant suitability drivers, and highly suitable habitats accounted for 62.9% of the reserve (8646.97 ha), forming three major forest blocks with low disturbance levels. Camera-trap detections (n = 58) showed strong concordance with model predictions (98.28% within moderately suitable or higher classes). Landscape metrics revealed contrasting spatial configurations between overall high-suitability habitats and optimal core patches, indicating that demographic source areas are embedded within fragmented peripheral mosaics. Medium patches and forested ridges may function as potential stepping stones and corridors facilitating movement across habitat clusters. These findings highlight the importance of maintaining functional connectivity and mitigating edge disturbances in buffer and experimental zones to ensure long-term population persistence and effective protected-area management for forest ungulates. Full article

This paper explores the feasibility of using acoustic wave propagation, particularly in the ultrasonic range, as a solution for data transmission in environments where traditional radio frequency (RF) communication is ineffective due to signal attenuation—such as in liquids or dense media like metal or stone. Leveraging GNU Radio and commercially available audio hardware, a low-cost, SDR (Software Defined Radio) system was developed to transmit data blocks (e.g., images, text, and audio) through various substances. The system employs BFSK (Binary Frequency Shift Keying) and BPSK (Binary Phase Shift Keying), operates at ultrasonic frequencies (typically 40 kHz), and has performance validated under real-world conditions, including water, viscous substances, and flammable liquids such as hydrocarbon fuels. Experimental results demonstrate reliable, continuous communication at Nyquist–Shannon sampling rates, with effective demodulation and file reconstruction. The methodology builds on concepts originally developed for Ad Hoc Sensor Networks in shipping containers, extending their applicability to submerged and RF-hostile environments. The modularity and flexibility of the GNU Radio platform allow for rapid adaptation across different media and deployment contexts. This work provides a reproducible and scalable communication solution for scenarios where RF transmission is impractical, offering potential applications in underwater sensing, industrial monitoring, railways, and enclosed infrastructure diagnostics. Across controlled laboratory experiments, the system achieved 100% successful reconstruction of transmitted image files up to 100 kB and sustained packet delivery success exceeding 98% under stable coupling conditions. Full article