Search Results (298)

Natural carbonate stones such as limestones and marbles are widely used in heritage and contemporary architecture, yet their durability is increasingly threatened by wildfire-related thermal stress. Since water transport plays a key role in stone deterioration, understanding how high temperatures affect hydric behavior is critical for conservation. This study investigates thirteen Portuguese carbonate lithotypes (including marbles, limestones, a travertine, and a breccia) exposed to temperatures of 300 °C and 600 °C. Capillary absorption and open porosity were measured, alongside Leeb hardness (HL) and ultrasonic pulse velocity (UPV), to evaluate their predictive capacity for post-fire moisture behavior. Results show that thermal exposure increases porosity and capillary uptake while reducing mechanical cohesion. Strong correlations between UPV and hydric parameters across temperature ranges highlight its reliability as a non-invasive diagnostic tool. HL performed well in compact stones but was less consistent in porous or heterogeneous lithologies. The findings support the use of NDT tests, like UPV and HL, for rapid post-fire assessments and emphasize the need for lithology-specific conservation strategies. Full article

The Korteweg–de Vries (KdV) equation is a nonlinear evolution equation that reflects a wide variety of dispersive wave occurrences with limited amplitude. It has also been used to describe a range of major physical phenomena, such as shallow water waves that interact weakly and nonlinearly, acoustic waves on a crystal lattice, lengthy internal waves in density-graded oceans, and ion acoustic waves in plasma. The KdV equation is one of the most well-known soliton models, and it provides a good platform for further research into other equations. The KdV equation has several forms. The aim of this study is to introduce and investigate a (2+1)-dimensional generalized fifth-order KdV equation with power law nonlinearity (gFKdVp). The research methodology employed is the Lie group analysis. Using the point symmetries of the gFKdVp equation, we transform this equation into several nonlinear ordinary differential equations (ODEs), which we solve by employing different strategies that include Kudryashov’s method, the $(G^{\prime }/G)$ expansion method, and the power series expansion method. To demonstrate the physical behavior of the equation, 3D, density, and 2D graphs of the obtained solutions are presented. Finally, utilizing the multiplier technique and Ibragimov’s method, we derive conserved vectors of the gFKdVp equation. These include the conservation of energy and momentum. Thus, the major conclusion of the study is that analytic solutions and conservation laws of the gFKdVp equation are determined. Full article

Water infiltration into soil is a key process in regulating the hydrological cycle and sustaining ecosystem services in high-Andean environments. However, limited information is available regarding its dynamics in these ecosystems. This study evaluated the influence of three types of vegetation cover and soil properties on water infiltration in a high-Andean environment. A double-ring infiltrometer, the Water Drop Penetration Time (WDPT, s) method, and laboratory physicochemical characterization were employed. Soils under forest cover exhibited significantly higher quasi-steady infiltration rates (i_s, 0.248 ± 0.028 cm·min⁻¹) compared to grazing areas (0.051 ± 0.016 cm·min⁻¹) and agricultural lands (0.032 ± 0.013 cm·min⁻¹). Soil organic matter content was positively correlated with i_s. The modified Kostiakov infiltration model provided the best overall fit, while the Horton model better described infiltration rates approaching i_s. Sand and clay fractions, along with K⁺, Ca²⁺, and Mg²⁺, were particularly significant during the soil’s wet stages. In drier stages, increased Na⁺ concentrations and decreased silt content were associated with higher water repellency. Based on WDPT, agricultural soils exhibited persistent hydrophilic behavior even after drying (median [IQR] from 0.61 [0.38] s to 1.24 [0.46] s), whereas forest (from 2.84 [3.73] s to 3.53 [24.17] s) and grazing soils (from 4.37 [1.95] s to 19.83 [109.33] s) transitioned to weakly or moderately hydrophobic patterns. These findings demonstrate that native Andean forest soils exhibit a higher infiltration capacity than soils under anthropogenic management (agriculture and grazing), highlighting the need to conserve and restore native vegetation cover to strengthen water resilience and mitigate the impacts of land-use change. Full article

The synergistic development of low-permeability reservoirs such as deep coalbed methane (CBM) and tight gas has emerged as a key technology to reduce development costs, enhance single-well productivity, and improve gas recovery. However, due to fundamental differences between coal seams and tight sandstones in their pore structure, permeability, water saturation, and pressure sensitivity, significant variations exist in their flow capacities and fluid production behaviors. To address the challenges of production allocation and main reservoir identification in the co-development of CBM and tight gas within deep gas-bearing basins, this study employs the transient multiphase flow simulation software OLGA to construct a representative dual-gas co-production well model. The regulatory mechanisms of the gas–liquid distribution, deliquification efficiency, and interlayer interference under two typical vertical stacking relationships—“coal over sand” and “sand over coal”—are systematically analyzed with respect to different tubing setting depths. A high-precision dynamic production allocation method is proposed, which couples the wellbore structure with real-time monitoring parameters. The results demonstrate that positioning the tubing near the bottom of both reservoirs significantly enhances the deliquification efficiency and bottomhole pressure differential, reduces the liquid holdup in the wellbore, and improves the synergistic productivity of the dual-reservoirs, achieving optimal drainage and production performance. Building upon this, a physically constrained model integrating real-time monitoring data—such as the gas and liquid production from tubing and casing, wellhead pressures, and other parameters—is established. Specifically, the model is built upon fundamental physical constraints, including mass conservation and the pressure equilibrium, to logically model the flow paths and phase distribution behaviors of the gas–liquid two-phase flow. This enables the accurate derivation of the respective contributions of each reservoir interval and dynamic production allocation without the need for downhole logging. Validation results show that the proposed method reliably reconstructs reservoir contribution rates under various operational conditions and wellbore configurations. Through a comparison of calculated and simulated results, the maximum relative error occurs during abrupt changes in the production capacity, approximately 6.37%, while for most time periods, the error remains within 1%, with an average error of 0.49% throughout the process. These results substantially improve the timeliness and accuracy of the reservoir identification. This study offers a novel approach for the co-optimization of complex multi-reservoir gas fields, enriching the theoretical framework of dual-gas co-production and providing technically adaptive solutions and engineering guidance for multilayer unconventional gas exploitation. Full article

Over 40% of freshwater fish species in Europe are currently at risk of extinction, highlighting the need for improved conservation planning. This study examines whether the threat status is associated with life-history and ecological traits across 580 autochthonous (native and endemic) freshwater fish species in European inland waters. Using data from FishBase and the IUCN Red List, we assessed associations between threat level and both categorical (e.g., migratory behavior, commercial importance, reproductive guild, and body shape) and numerical traits (e.g., maximum length, weight, age, growth parameters, and maturity traits). Significant, though modest, associations were identified between species threat level and migratory behavior and reproductive guild. Non-migratory species exhibited higher median threat levels, while amphidromous species showed a non-significant trend toward higher threat, suggesting that limited dispersal ability and dependence on fragmented freshwater networks may increase extinction vulnerability. Species with unclassified reproductive strategies also showed elevated threat levels, possibly reflecting both actual risk and underlying data gaps. In contrast, body shape and trophic level were not significantly associated with threat status. Critically Endangered species tend to be larger, heavier, and mature later—traits characteristic of slow life history strategies that limit population recovery. Although length at maturity and maximum age did not differ significantly among IUCN categories, age at maturity was significantly higher in more threatened species, and growth rate (K) was negatively correlated with threat level. Together, these patterns suggest that slower-growing, later-maturing species face elevated extinction risk. Overall, the findings underscore that the threat level in European freshwater fish is shaped by complex interactions between intrinsic biological traits and external pressures. Trait-based approaches can enhance extinction risk assessments and conservation prioritization, especially in data-deficient freshwater ecosystems facing multifaceted environmental challenges. Full article

The conservation and restoration of water-gilded wooden cultural heritage, such as polychrome sculptures, frames, panels, altarpieces, etc., requires the use of fillers that guarantee structural stability, physicochemical and mechanical compatibility with the original support, and the ability to adapt to dimensional movements induced by thermo-hygrometric variations. This study, conducted as part of the DorART Project, analyzed the behavior of nine formulations, both commercial and non-commercial, selected through a review of the state-of-the-art specialized literature, along with the use of participatory science, which focused on the practices and materials most commonly used by professionals in the field. The experimental design was based on three types of specimens: two with wooden supports, selected for evaluating their interaction with the original material and with the traditional water gilding technique, and a third type for analyzing the individual behavior of the tested materials. Analyses of adhesion, tensile strength, Shore C hardness, gloss, abrasion test results, wettability, pH changes, and chemical composition were performed using ATR-FTIR spectroscopy. The results showed significant differences depending on the type of curing used and the composition and aging behavior of the specimen. Some of the fillers demonstrated improved compatibility with water-based gilding, facilitating workability and providing structural strength. M3 and M9 demonstrated an optimal balance of workability and aging stability. The results of this study can help restorers select materials based on their specific needs, considering the requirements of mechanical adaptation to the substrate, compatibility, and durability. Full article

Postharvest losses and limited physiological knowledge restrict the conservation and year-round availability of underutilized crops such as Dioscorea trifida. This study characterized the postharvest behavior of Colombian purple D. trifida tubers and evaluated low-cost, GRAS-status technologies to improve storage performance in smallholder production systems. Tubers were stored for 34 days at ambient conditions (20 °C, 90% RH) and compared with treatments including cold storage, calcium pretreatments combined with Aloe vera-based coatings, and short-duration hot water immersion. Over storage, total carbohydrates increased, while potassium remained at substantial levels until the final day. Weight loss and respiration declined steadily, and sprouting was absent, suggesting extended endodormancy in this genotype. Major deterioration causes observed upon reception included fragmentation, insect damage, and surface molds, highlighting the importance of improved sanitation and mechanical protection during harvest, early postharvest stages, and transportation. Edible coatings enhanced antioxidant activity and increased malic and succinic acid concentrations. Cold storage at 3 °C reduced weight loss more effectively than storage at 12 or 20 °C, although citric acid accumulation was greater at the latter temperature. Among all treatments, immersion at 55 °C for 5 min was the most promising, offering a scalable, low-input option to extend shelf life in neglected yam species. Full article

Wetlands are critically important ecosystems, but their dynamics, especially in complex regions such as the Ukrainian Polissya, remain poorly understood. This study focuses on the Cheremsky Nature Reserve, an internationally important wetland, to assess long-term (2017–2024) seasonal (spring-summer) trends in water surface conditions. Using Sentinel-2 data and the Google Earth Engine platform, 14 spectral water indices were calculated. Their temporal trends were analyzed using Sen’s method, mutual correlations, and principal component analysis (PCA) to identify the main patterns of variability. Based on the normalized trends and weights obtained from the first two principal components, an integral composite index (CI) for spring and summer seasons was developed. The results revealed seasonal differences in the behavior of the indices and their contribution to the principal components, as well as spatial differentiation of water regime trends within the reserve. The proposed CI allows for an integrated assessment of the long-term dynamics of the wetlands, which is important for the development of conservation and management strategies. Full article

Background and Objectives: Conventional methods for removing cemented fixed prosthetic restorations (FPRs) are unreliable and lead to unsatisfactory outcomes. At their best, they allow the tooth to be saved at the expense of a laborious process that also wears down rotating tools and handpieces and occasionally results in abutment fractures. Restorations are nearly never reusable in any of these situations. Erbium-doped yttrium-aluminum-garnet (Er:YAG) and erbium-chromium yttrium-scandium-gallium-garnet (Er,Cr:YSGG) lasers casafely and effectively remove FPRs, according to scientific studiesre. This study sets out to examine the impact of Er:YAG laser radiation on the debonding of different ceramic restorations, comparing the behavior of various ceramic prosthetic restoration types under laser radiation action and evaluating the integrity of prosthetic restorations and dental surfaces exposed to laser radiation. Materials and Methods: The study included a total of 16 removed teeth, each prepared on opposite surfaces as abutments.y. Based on the previously defined groups, four types of ceramic restorations were included in the study: feldspathic (F), lithium disilicates (LD), layered zirconia (LZ), and monolithic zirconia (MZ). The thickness of the prosthetic restorations was measured at three points, and two different materials were used for cementation. The Er:YAG Fotona StarWalker MaQX laser was used to debond the ceramic FPR at a distance of 10 mm using an R14 sapphire tip with 275 mJ, 20 Hz, 5.5 W, with air cooling (setting 1 of 9) and water. After debonding, the debonded surface was visualized under electron microscopy. Results: A total of 23 ceramic FPRs were debonded, of which 12 were intact and the others fractured into two or three pieces. The electron microscopy images showed that debonding took place without causing any harm to the tooth structure. The various restoration types had the following success rates: 100% for the LZ and F groups, 87% for the LD group, and 0% for the MZ group. In terms of cement type, debonding ceramic FPRs cemented with RELYX was successful 75% of the time, compared to Variolink DC’s 69% success rate. Conclusions: In summary, the majority of ceramic prosthetic restorations can be successfully and conservatively debonded with Er:YAG radiation. Full article

The crystallization of soluble salts is one of the most significant agents of deterioration affecting porous building materials in historical architecture. This process not only compromises the physical integrity of the materials but also results in considerable aesthetic, structural, and economic consequences. Soluble salts involved in these processes may originate from geogenic sources—including soil leachate, marine aerosols, and the natural weathering of parent rocks—or from anthropogenic factors such as air pollution, wastewater infiltration, and the use of incompatible restoration materials. This study examines the role of capillary rise as a primary mechanism responsible for the vertical migration of saline solutions from the soil profile into historic masonry structures, especially those constructed with calcareous stones. It describes how water retained or sustained within the soil matrix ascends via capillarity, carrying dissolved salts that eventually crystallize within the pore network of the stone. This phenomenon leads to a variety of damage types, ranging from superficial staining and efflorescence to more severe forms such as subflorescence, microfracturing, and progressive mass loss. By adopting a multidisciplinary approach that integrates concepts and methods from soil physics, hydrology, petrophysics, and conservation science, this paper examines the mechanisms that govern saline water movement, salt precipitation patterns, and their cumulative effects on stone durability. It highlights the influence of key variables such as soil texture and structure, matric potential, hydraulic conductivity, climatic conditions, and stone porosity on the severity and progression of deterioration. This paper also addresses regional considerations by focusing on the context of Spain, which holds one of the highest concentrations of World Heritage Sites globally and where many monuments are constructed from vulnerable calcareous materials such as fossiliferous calcarenites and marly limestones. Special attention is given to the types of salts most commonly encountered in Spanish soils—particularly chlorides and sulfates—and their thermodynamic behavior under fluctuating environmental conditions. Ultimately, this study underscores the pressing need for integrated, preventive conservation strategies. These include the implementation of drainage systems, capillary barriers, and the use of compatible materials in restoration, as well as the application of non-destructive diagnostic techniques such as electrical resistivity tomography and hyperspectral imaging. Understanding the interplay between soil moisture dynamics, salt crystallization, and material degradation is essential for safeguarding the cultural and structural value of historic buildings in the face of ongoing environmental challenges and climate variability. Full article

Drought stress severely limits agricultural productivity, with atmospheric and soil water deficits often occurring simultaneously in field conditions. While plant responses to individual drought factors are well-documented, recovery mechanisms following combined atmospheric–soil drought remain poorly understood, hindering drought resistance strategies and irrigation optimization. We set up two VPD treatments (low and high vapor pressure deficit) and two soil moisture treatments (CK: control soil moisture with sufficient irrigation, 85–95% field capacity; drought: soil moisture with deficit irrigation, 50–60% field capacity) in the pot experiment. We investigated wheat’s hydraulic transport (leaf hydraulic conductance, K_leaf) and gas exchange (stomatal conductance, g_s; photosynthetic rate, A_n) responses to combined drought stress from atmospheric and soil conditions at the heading stage, as well as rewatering 55 days after treatment initiation. The results revealed that: (1) high VPD and soil drought significantly reduced leaf hydraulic conductance (K_leaf), with a high VPD decreasing K_leaf by 31.6% and soil drought reducing K_leaf by 33.2%; The high VPD decreased stomatal conductance (g_s) by 43.6% but the photosynthetic rate (A_n) by only 12.3%; (2) After rewatering, g_s and A_n of atmospheric and soil drought recovered relatively rapidly, while K_leaf did not; (3) Atmospheric and soil drought stress led to adaptive changes in wheat’s stomatal regulation strategies, with an increasing severity of drought stress characterized by a shift from non-conservative to conservative water regulation behavior. These findings elucidate wheat’s hydraulic–stomatal coordination mechanisms under drought stress and their differential recovery patterns, providing theoretical foundation for improved irrigation management practices. Full article

Comprehending the alterations in wintering grounds of migratory birds amid global change and anthropogenic influences is pivotal for advancing wetland sustainability and ensuring avian conservation. Frequent extreme droughts in the middle and lower Yangtze River region of China have posed severe ecological and socio-economic dilemmas. The integration of internet-derived, crowdsourced geographic data with remote-sensing imagery now facilitates assessments of these avian habitats. Poyang Lake, China’s largest freshwater body, suffered an unprecedented drought in 2022, offering a unique case study on avian habitat responses to climate extremes. By harnessing social and online platforms’ media reports, we analyzed the types, attributes and proportions of migratory bird habitats. This crowdsourced geographic information, corroborated by Sentinel-2 optical remote-sensing imagery, elucidated the suitability and transformations of these habitats under drought stress. Our findings revealed marked variations in habitat preferences among bird species, largely attributable to divergent feeding ecologies and behavioral patterns. Dominantly, shallow waters emerged as the most favored habitat, succeeded by mudflats and grasslands. Remote-sensing analyses disclosed a stark 60% reduction in optimal habitat area during the drought phase, paralleled by a 1.5-fold increase in unsuitable habitat areas compared to baseline periods. These prime habitats were chiefly localized in Poyang Lake’s western sub-lakes. The extreme drought precipitated a drastic contraction in suitable habitat extent and heightened fragmentation. Our study underscores the value of crowdsourced geographic information in assessing habitat suitability for migratory birds. Retaining sub-lake water surfaces within large river or lake floodplains during extreme droughts emerges as a key strategy to buffer the impacts of hydrological extremes on avian habitats. This research contributes to refining conservation strategies and promoting adaptive management practices of wetlands in the face of climate change. Full article

Understanding the feeding ecology and habitat use of vulnerable shark species is crucial for effective conservation. This study focuses on two large filter-feeding sharks, the megamouth shark (Megachasma pelagios) and whale shark (Rhincodon typus), in Northwestern Pacific waters. Stable isotope analysis (δ¹³C and δ¹⁵N) was conducted on white muscle samples (n = 91) of M. pelagios and fin clips (n = 90) of R. typus, collected via large-mesh drift nets and set nets in Taiwanese waters. In this study, we investigated feeding strategies, ontogenetic dietary shifts, habitat use, and isotopic niche variation in both species. For R. typus, the observed positive correlation between δ¹³C and δ¹⁵N supports the previously proposed active suction filter feeding, as well as implying both a diet with an increasing proportion of higher trophic level prey and an ontogenetic shift. In contrast, M. pelagios displayed a negative correlation, consistent with a previous study associating such patterns with primary or secondary consumers, further aligning with its reported planktonic prey dominance. Both species had increasing δ¹³C with growth, signifying a shift to nutrient-rich habitats. Only R. typus exhibited ontogenetic diet changes (δ¹⁵N). SIBER (Stable Isotope Bayesian Ellipses in R) analysis revealed distinct feeding strategies and habitat use between the two species, potential sexual segregation, and wider isotopic niche widths for males in both species. The findings underscore the importance of considering species-specific behaviors and sex-based differences in conservation strategies. Full article

The conservation of biodiversity and the balance between ecological and societal needs are critical but often contested global issues. Wildlife-vehicle collision (WVC) on vital infrastructure, especially linear infrastructure, remains a persistent challenge from policy to practice and poses a serious life-threatening implication to humans and other non-human lives. Addressing this issue effectively requires solutions that provide win-win outcomes from both ecological and societal perspectives. This study critically analyzes a decade of roadkill incidents along Nepal’s longest East-West national highway, which passes through a biologically diverse national park in the western Terai Arc Landscape Area (TAL). Findings are drawn from field-based primary data collection of the period 2012–2022, secondary literature review, key informant interviews, and spatial analysis. The study reveals significant variations in roadkill incidence across areas and years. Despite Bardia National Park being larger and having a higher wildlife density, Banke National Park recorded higher roadkill rates. This is attributed to insufficient mitigation measures and law enforcement, more straight highway segments, and the absence of buffer zones between the core park and adjacent forest areas—only a road separates them. Wild boars (Sus scrofa) and spotted deer (Axis axis), the primary prey of Bengal tigers (Panthera tigris tigris), were the most frequently road-killed species. This may contribute to human-tiger conflicts, as observed in the study areas. Seasonal trends showed that reptiles were at higher risk during the wet season and mammals during winter. Hotspots were often located near checkpoints and water bodies, highlighting the need for targeted mitigation efforts such as wildlife crossings and provisioning wildlife requirements such as water, grassland, and shelter away from the regular traffic roads. Roadkill frequency was also influenced by forest cover and time of day, with more incidents occurring at dawn and dusk when most of the herbivores become more active in search of food, shelter, water, and their herds. The findings underscore the importance of road characteristics, animal behavior, and landscape features in roadkill occurrences. Effective mitigation strategies include wildlife crossings, speed limits, warning signs, and public education campaigns. Further research is needed to understand the factors in driving variations between parks and to assess the effectiveness of mitigation measures. Full article

Latent heat thermal energy storage systems play a crucial role in aligning energy supply with demand, enhancing the efficiency of energy usage, thereby aiding in energy conservation and emissions reduction, and promoting the efficient use of renewable energy. Therefore, we constructed an experimental apparatus for a shell-and-tube latent heat storage. This apparatus was utilized to investigate how varying the inclination angle of the heat storage device, the inlet temperature of the heat transfer fluid (HTF), and water flow direction affect both the heat transfer behavior and the thermal efficiency of the system. The findings indicate that as the inlet temperature rises, the melting rate of the phase-change material (PCM) increases; when the inclination angle is 0°, for every 5 °C increase in water temperature, the time required to reach thermal equilibrium is shortened by 2 h, and the time needed for the PCM to transition from a solid to a liquid state is correspondingly reduced by 2 h. Additionally, the temperature variation trend of the phase-change material remains fundamentally consistent at different inclination angles. However, as the angle increases from 0° to 90°, there is a gradual reduction in the melting rate. Whether the water enters from the top or bottom, the melting rate of the PCM remains almost unchanged, and the stabilized temperature of the PCM is also nearly the same. Full article