Atmospheric and Oceanic Sciences

The thermal-mechanical coupling effects induced by thermal injection during coalbed methane extraction can readily lead to coal seam instability. To investigate the influence of real-time temperature on the damage characteristics of coal, uniaxial compression tests were conducted on coal specimens under real-time temperature conditions using the MTS 815 testing system equipped with high-temperature accessories. Combined with the PFC3D discrete element numerical model, a cross-scale analysis was performed to examine the mechanical degradation patterns and fracture evolution characteristics of the coal. Based on a temperature-load coupled damage variable approach, a segmented damage model under combined thermal-mechanical effects was developed. The results show that the peak strain of coal is positively correlated with temperature, whereas compressive strength and elastic modulus exhibit a negative correlation. Thermal damage degree is positively correlated with temperature, with thermal cracks being predominantly tensile. During loading, as temperature increases, the macroscopic failure mode gradually shifts from axial splitting to mixed tensile-shear failure. Microdamage observed in PFC simulations similarly evolves from a predominance of tensile cracks to a mixed pattern, accompanied by a significant increase in the strain range between the initiation point and the peak point, indicating enhanced ductility. To account for the thermal sensitivity and the influence of temperature on failure mechanism, a Gaussian decay function based on a Gaussian kernel function was constructed to reconstruct the post-peak curve of the traditional Weibull model, substantially improving the model's descriptive capability. The proposed damage constitutive model is applicable to thermomechanically coupled uniaxial compression tests on coal and accurately captures the damage evolution process. The findings provide theoretical support for assessing coal seam stability during thermal injection mining.

This study investigated indoor environmental air quality (IEAQ) across university workspaces at a higher education institution in Sharjah, United Arab Emirates (UAE), assessing environmental conditions that may influence occupant health, the surrounding environment, and sustainability. Physical parameters (temperature, relative humidity, noise, and illuminance), chemical parameters (indoor gases and particulate matter), and biological contaminants (airborne bacteria and fungi) were measured in semi-occupied indoor environments with a total of 68 random samples collected and analyzed. Perceived heat discomfort and environmental variability were assessed using the Thom Discomfort Index (TDI), Humidex Index, ANOVA, Kruskal–Wallis, Mann–Whitney U, and one-sample t-tests. Average measurements of relative humidity, temperature, noise, and illuminance were 60.7%, 21.6 °C, 57.5 dB, and 440 lux, respectively. Average concentrations of PM2.5, PM10, CO, and CO2 were 1223 ppm, 104 ppm, 1 ppm, and 623 ppm, respectively. Microbial contamination was generally insignificant across most investigated workspaces. While most measured parameters remained within recommended threshold limit values (TLVs), elevated levels of noise, illuminance, and particulate matter were observed in selected workspaces. These findings demonstrate that university indoor environments generally maintain acceptable air quality conditions; however, targeted interventions, including improved HVAC maintenance and indoor pollutant management, are required to enhance sustainable university indoor environments and optimize occupant comfort.

Introduction Ground-based timber extraction is one of the most important harvesting methods used around the world, but it also causes negative effects on forest soils, to a degree that depends on machine mass, soil condition, and operational decisions. Skidding, in particular, may cause compaction in the deeper soil layers and soil mixing at the surface due to the way timber is extracted. Although several studies have examined soil compaction following timber extraction, few have been conducted under controlled measurement and comparison conditions; in addition, the heterogeneity of soil conditions makes it unlikely that existing results can be applied to the wide variety of conditions encountered in regular forest operations. Methods In this study, a controlled experiment was set up to evaluate the effect of successive machine passes on soil compaction, measured as resistance to penetration, specifically accounting for loads typical to selective, final harvests. Measurements of resistance to penetration were taken at 10 control points and then at 10 points located on the wheel footprints after the first, third, fifth, and tenth loaded machine passes, while the machine payload remained constant and there was no ground slope. Variation in resistance to penetration from 0 to 80 cm depth was visually assessed, and the data were partitioned for comparison into 5 cm soil layers from the surface downward. Results and discussion While the first three passes caused significant but small changes in the upper soil layer, more important changes were found after the fifth and tenth machine passes. Five passes caused an increase in resistance to penetration of about 1.0 MPa, particularly in the first 15 cm of soil. After 10 machine passes, resistance to penetration increased further, particularly in the soil layer between 5 and 15 cm depth, although not statistically significant, increases in mean resistance to penetration were also found below the first 15–20 cm of soil. Under the specific conditions of this study (flat terrain, luvisol, full payload, autumn soil moisture), three loaded machine passes did not appear to cause persistent severe soil compaction. This finding should not be generalized without accounting for differences in soil moisture, terrain slope, and machine type. The results of this study are useful for planning, since the number of passes over the same skid trail may be controlled through a well-developed trail network and careful operational planning so as to avoid irreversible soil compaction.

ABSTRACT An attempt has been made to understand the subsurface lithologic information and to delineate the ground water potential zones in the hard Rock Terrene of Malwa Plateau, Madhya Pradesh, using the Geophysical methods. The area exhibits highly variable groundwater availability. Vertical Electrical soundings (VES) were carried out in the study area at thirty-two locations, in which resistivity values range from 3.7 to 3500 Ωm. The area is characterised by the topsoil followed by weathered basalts, vesicular basalt, fractured basalt, and massive basalts. The entire area is covered by Deccan basalts and forms the major aquifer. In the VES, two main types of aquifers, Aquifer I and II, were identified. The thickness of Aquifer I range from 1.3 to 22.3 m, while Aquifer II varies from 2.7 to 21.5 m. The variation in thickness of these aquifers indicates heterogeneous subsurface conditions, typical of hard-rock terranes where groundwater occurs mainly in weathered and fractured zones. Delineating groundwater potential zones, therefore, provides critical insight into the spatial distribution of these aquifer characteristics, enabling more informed decisions for sustainable groundwater management and long-term development in the study area.

Abstract Exhumed metamorphic rocks yield critical insights into the mechanical, chemical, and thermal structure of the plate interface that can be used to infer exhumation pathways and their evolution throughout a subduction zone's lifetime. Metamorphosed oceanic rocks often record exhumation and underplating over relatively punctuated time periods, which appear to be linked to specific stages of subduction. Although plate velocities also vary from one stage of subduction to the next, the influence of this time dependence on exhumation and underplating remains unclear. We therefore use 2‐D time‐dependent subduction models to investigate how evolving plate velocities affect the timing and distribution of exhumation and underplating. By extracting plate velocities from a freely evolving subduction model and imposing them on kinematically driven models, we isolate the effects of realistic velocity variations on interface processes without the complexity of a dynamically evolving slab. We also explore the role of interface strength by varying its rheology and composition. In our models, exhumation consistently initiates during a punctuated detachment event following decreases in subduction velocity. Shallow exhumation (<50 km) occurs through corner flow within the accretionary prism, while deeper underplating (<140 km) involves crustal slicing and detachment along the whole interface. Weak interfaces favor continuous and voluminous exhumation, whereas strong interfaces restrict it to brief, punctuated episodes. Underplating is discontinuous throughout but increases in volume as convergence slows. These findings demonstrate that time‐dependent plate velocity variations exert significant control on interface processes and naturally generate punctuated exhumation and underplating consistent with the rock record.

The evolutionary assembly of the flight-adapted bird body plan encompasses some of the most profound morphological changes in terrestrial vertebrate history. Beyond feathered wings, the short pygostyle-bearing tail has been pivotal to the clade’s ecological success. However, transition from the long bony tail to the short pygostyle-bearing tail remains a mystery, hindered by the scarcity of early branching avialans with transitional morphologies. Here, we report on a new avialan, Zhengheornis buyu , gen. et sp. nov., from the Upper Jurassic of southeastern China, suggesting that the vertebral reduction and shortening preceded pygostyle fusion in early avialan evolution, providing critical evidence for the stepwise evolution of the bird tail. Z. buyu is smaller than all known non-pygostylian paravians, expanding the species and body size diversity of stemward taxa.

Widespread forest degradation poses a serious threat to ecological balance and long-term sustainability. Many forest conservation policies have shown limited effectiveness because they overlook the governance role of indigenous communities and the local wisdom embedded in customary institutions. This study examines how local wisdom functions as a form of community-based forest governance and explores its implications for environmental education policy. The research aims to identify and analyze the forms of local wisdom still practiced by indigenous communities in Indonesia, in regulating and protecting forest resources. Using a qualitative approach, data were collected through participatory observation, in-depth interviews with indigenous leaders and community members, and documentation of customary laws, traditional manuscripts, and everyday practices. Thematic analysis was employed to identify patterns of values, norms, and governance mechanisms related to forest conservation. The findings reveal that local wisdom operates not merely as cultural heritage but as a living socio-ecological governance system that regulates access, enforces customary prohibitions, structures spatial management, and sustains biodiversity. These customary governance mechanisms demonstrate effectiveness in preventing overexploitation and maintaining ecological balance. The study further argues that recognizing such local governance systems should inform environmental education policy, particularly by integrating indigenous conservation principles into formal curricula to strengthen ecological awareness and sustainability values in primary education.

ABSTRACT This synthesis integrates five decades of regional and local structural mapping, geochemistry, geochronology, and geophysical data to propose a unified tectono-metallogenic model for Neoarchaean orogenic gold mineralisation in the Dharwar Craton (DC). The paper advocates a working hypothesis that the Craton evolved within a Phanerozoic-style convergent plate tectonic regime, characterised by westward low-angle subduction of oceanic lithosphere beneath an extant Mesoarchaean continental fragment. This process drove the inversion of Neoarchaean ensialic half-graben volcano-sedimentary basins into west-verging fold-thrust belts, emplacement of tabular plutons of granitoids, followed by craton-scale sinistral shearing. These structural events provided the necessary architecture for vertical, channelised fluid flow, resulting in a craton-wide gold depositional event within a short pulse between 2.54-2.52 Ga. The proposed framework unifies diverse geological datasets and offers critical insights for future gold exploration strategies within the Craton.

ABSTRACT The Vempalle Formation of Papaghni sub-basin in the southwestern margin of Cuddapah Basin (CB) hosts low-grade, large tonnage uranium deposits collectively called ‘Tummalapalle Group Uranium Deposits’ and has been recognised as a major uranium province in India. These uranium deposits are hosted by uraniferous phosphatic siliceous dolostone (UPSD). UPSD has several enigmatic characters, such as regional dolomicrite blanketing, laminated structure, signatures of gas seep structures, negative δ13C values (~0 to −2.9‰), contrasting primary sedimentary structures indicating shallow and deep marine conditions, contrasting marine and continental sediments like alternate carbonate-rich and phosphate-rich layers mixed with quartz and felspar clasts. Geochemically, it has higher SiO2 (22.62%), Al2O3 (2.64 %), FeO (0.74%), and P2O5 (0.75%) with lesser CaO (22.58%) than common dolostones. Interestingly, UPSD sediments are unusually enriched in redox-sensitive elements like Mo, Cu and V. Signatures of the Supercontinent cycle are observed across the Archaean-Proterozoic boundary in the Papaghni sub-basin at the base of the Cuddapah basin, in the Eastern Dharwar Craton. Glaciation is inferred to be associated with the Supercontinent cycle. UPSD is identified as a Cap Carbonate Rock (CCR), deposited during glacial melting. Methane released during the glacial melting appears to have reduced uranium derived from the surrounding provenance. This new perspective is proposed for the uranium mineralisation.